src/third-party/libpng/contrib/libtests/pngvalid.c (view raw)
1
2/* pngvalid.c - validate libpng by constructing then reading png files.
3 *
4 * Last changed in libpng 1.6.31 [July 27, 2017]
5 * Copyright (c) 2014-2017 John Cunningham Bowler
6 *
7 * This code is released under the libpng license.
8 * For conditions of distribution and use, see the disclaimer
9 * and license in png.h
10 *
11 * NOTES:
12 * This is a C program that is intended to be linked against libpng. It
13 * generates bitmaps internally, stores them as PNG files (using the
14 * sequential write code) then reads them back (using the sequential
15 * read code) and validates that the result has the correct data.
16 *
17 * The program can be modified and extended to test the correctness of
18 * transformations performed by libpng.
19 */
20
21#define _POSIX_SOURCE 1
22#define _ISOC99_SOURCE 1 /* For floating point */
23#define _GNU_SOURCE 1 /* For the floating point exception extension */
24
25#include <signal.h>
26#include <stdio.h>
27
28#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
29# include <config.h>
30#endif
31
32#ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */
33# include <fenv.h>
34#endif
35
36#ifndef FE_DIVBYZERO
37# define FE_DIVBYZERO 0
38#endif
39#ifndef FE_INVALID
40# define FE_INVALID 0
41#endif
42#ifndef FE_OVERFLOW
43# define FE_OVERFLOW 0
44#endif
45
46/* Define the following to use this test against your installed libpng, rather
47 * than the one being built here:
48 */
49#ifdef PNG_FREESTANDING_TESTS
50# include <png.h>
51#else
52# include "../../png.h"
53#endif
54
55#ifdef PNG_ZLIB_HEADER
56# include PNG_ZLIB_HEADER
57#else
58# include <zlib.h> /* For crc32 */
59#endif
60
61/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
62 * a skipped test, in earlier versions we need to succeed on a skipped test, so:
63 */
64#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
65# define SKIP 77
66#else
67# define SKIP 0
68#endif
69
70/* pngvalid requires write support and one of the fixed or floating point APIs.
71 */
72#if defined(PNG_WRITE_SUPPORTED) &&\
73 (defined(PNG_FIXED_POINT_SUPPORTED) || defined(PNG_FLOATING_POINT_SUPPORTED))
74
75#if PNG_LIBPNG_VER < 10500
76/* This deliberately lacks the const. */
77typedef png_byte *png_const_bytep;
78
79/* This is copied from 1.5.1 png.h: */
80#define PNG_INTERLACE_ADAM7_PASSES 7
81#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
82#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
83#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
84#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
85#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
86 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
87#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
88 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
89#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
90 (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
91#define PNG_COL_FROM_PASS_COL(xIn, pass) \
92 (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
93#define PNG_PASS_MASK(pass,off) ( \
94 ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
95 ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
96#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
97 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
98#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
99 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
100
101/* These are needed too for the default build: */
102#define PNG_WRITE_16BIT_SUPPORTED
103#define PNG_READ_16BIT_SUPPORTED
104
105/* This comes from pnglibconf.h afer 1.5: */
106#define PNG_FP_1 100000
107#define PNG_GAMMA_THRESHOLD_FIXED\
108 ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
109#endif
110
111#if PNG_LIBPNG_VER < 10600
112 /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
113 * compiled against earlier versions.
114 */
115# define png_const_structp png_structp
116#endif
117
118#ifndef RELEASE_BUILD
119 /* RELEASE_BUILD is true for releases and release candidates: */
120# define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
121#endif
122#if RELEASE_BUILD
123# define debugonly(something)
124#else /* !RELEASE_BUILD */
125# define debugonly(something) something
126#endif /* !RELEASE_BUILD */
127
128#include <float.h> /* For floating point constants */
129#include <stdlib.h> /* For malloc */
130#include <string.h> /* For memcpy, memset */
131#include <math.h> /* For floor */
132
133/* Convenience macros. */
134#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
135#define CHUNK_IHDR CHUNK(73,72,68,82)
136#define CHUNK_PLTE CHUNK(80,76,84,69)
137#define CHUNK_IDAT CHUNK(73,68,65,84)
138#define CHUNK_IEND CHUNK(73,69,78,68)
139#define CHUNK_cHRM CHUNK(99,72,82,77)
140#define CHUNK_gAMA CHUNK(103,65,77,65)
141#define CHUNK_sBIT CHUNK(115,66,73,84)
142#define CHUNK_sRGB CHUNK(115,82,71,66)
143
144/* Unused formal parameter errors are removed using the following macro which is
145 * expected to have no bad effects on performance.
146 */
147#ifndef UNUSED
148# if defined(__GNUC__) || defined(_MSC_VER)
149# define UNUSED(param) (void)param;
150# else
151# define UNUSED(param)
152# endif
153#endif
154
155/***************************** EXCEPTION HANDLING *****************************/
156#ifdef PNG_FREESTANDING_TESTS
157# include <cexcept.h>
158#else
159# include "../visupng/cexcept.h"
160#endif
161
162#ifdef __cplusplus
163# define this not_the_cpp_this
164# define new not_the_cpp_new
165# define voidcast(type, value) static_cast<type>(value)
166#else
167# define voidcast(type, value) (value)
168#endif /* __cplusplus */
169
170struct png_store;
171define_exception_type(struct png_store*);
172
173/* The following are macros to reduce typing everywhere where the well known
174 * name 'the_exception_context' must be defined.
175 */
176#define anon_context(ps) struct exception_context *the_exception_context = \
177 &(ps)->exception_context
178#define context(ps,fault) anon_context(ps); png_store *fault
179
180/* This macro returns the number of elements in an array as an (unsigned int),
181 * it is necessary to avoid the inability of certain versions of GCC to use
182 * the value of a compile-time constant when performing range checks. It must
183 * be passed an array name.
184 */
185#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
186
187/* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires
188 * some broken GCC versions to be fixed up to avoid invalid whining about auto
189 * variables that are *not* changed within the scope of a setjmp being changed.
190 *
191 * Feel free to extend the list of broken versions.
192 */
193#define is_gnu(major,minor)\
194 (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor)
195#define is_gnu_patch(major,minor,patch)\
196 is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0
197/* For the moment just do it always; all versions of GCC seem to be broken: */
198#ifdef __GNUC__
199 const void * volatile make_volatile_for_gnu;
200# define gnu_volatile(x) make_volatile_for_gnu = &x;
201#else /* !GNUC broken versions */
202# define gnu_volatile(x)
203#endif /* !GNUC broken versions */
204
205/******************************* UTILITIES ************************************/
206/* Error handling is particularly problematic in production code - error
207 * handlers often themselves have bugs which lead to programs that detect
208 * minor errors crashing. The following functions deal with one very
209 * common class of errors in error handlers - attempting to format error or
210 * warning messages into buffers that are too small.
211 */
212static size_t safecat(char *buffer, size_t bufsize, size_t pos,
213 const char *cat)
214{
215 while (pos < bufsize && cat != NULL && *cat != 0)
216 buffer[pos++] = *cat++;
217
218 if (pos >= bufsize)
219 pos = bufsize-1;
220
221 buffer[pos] = 0;
222 return pos;
223}
224
225static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
226{
227 char number[64];
228 sprintf(number, "%d", n);
229 return safecat(buffer, bufsize, pos, number);
230}
231
232#ifdef PNG_READ_TRANSFORMS_SUPPORTED
233static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
234 int precision)
235{
236 char number[64];
237 sprintf(number, "%.*f", precision, d);
238 return safecat(buffer, bufsize, pos, number);
239}
240#endif
241
242static const char invalid[] = "invalid";
243static const char sep[] = ": ";
244
245static const char *colour_types[8] =
246{
247 "grayscale", invalid, "truecolour", "indexed-colour",
248 "grayscale with alpha", invalid, "truecolour with alpha", invalid
249};
250
251#ifdef PNG_READ_TRANSFORMS_SUPPORTED
252/* Convert a double precision value to fixed point. */
253static png_fixed_point
254fix(double d)
255{
256 d = floor(d * PNG_FP_1 + .5);
257 return (png_fixed_point)d;
258}
259#endif /* PNG_READ_SUPPORTED */
260
261/* Generate random bytes. This uses a boring repeatable algorithm and it
262 * is implemented here so that it gives the same set of numbers on every
263 * architecture. It's a linear congruential generator (Knuth or Sedgewick
264 * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
265 * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
266 * Generation.)
267 */
268static void
269make_random_bytes(png_uint_32* seed, void* pv, size_t size)
270{
271 png_uint_32 u0 = seed[0], u1 = seed[1];
272 png_bytep bytes = voidcast(png_bytep, pv);
273
274 /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
275 * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
276 */
277 size_t i;
278 for (i=0; i<size; ++i)
279 {
280 /* First generate 8 new bits then shift them in at the end. */
281 png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
282 u1 <<= 8;
283 u1 |= u0 >> 24;
284 u0 <<= 8;
285 u0 |= u;
286 *bytes++ = (png_byte)u;
287 }
288
289 seed[0] = u0;
290 seed[1] = u1;
291}
292
293static void
294make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
295{
296 make_random_bytes(seed, bytes, 4);
297}
298
299#if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\
300 defined PNG_WRITE_FILTER_SUPPORTED
301static void
302randomize(void *pv, size_t size)
303{
304 static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
305 make_random_bytes(random_seed, pv, size);
306}
307
308#define R8(this) randomize(&(this), sizeof (this))
309
310#ifdef PNG_READ_SUPPORTED
311static png_byte
312random_byte(void)
313{
314 unsigned char b1[1];
315 randomize(b1, sizeof b1);
316 return b1[0];
317}
318#endif /* READ */
319
320static png_uint_16
321random_u16(void)
322{
323 unsigned char b2[2];
324 randomize(b2, sizeof b2);
325 return png_get_uint_16(b2);
326}
327
328#if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
329 defined PNG_READ_FILLER_SUPPORTED
330static png_uint_32
331random_u32(void)
332{
333 unsigned char b4[4];
334 randomize(b4, sizeof b4);
335 return png_get_uint_32(b4);
336}
337#endif /* READ_FILLER || READ_RGB_TO_GRAY */
338
339#endif /* READ || WRITE_tRNS || WRITE_FILTER */
340
341#if defined PNG_READ_TRANSFORMS_SUPPORTED ||\
342 defined PNG_WRITE_FILTER_SUPPORTED
343static unsigned int
344random_mod(unsigned int max)
345{
346 return random_u16() % max; /* 0 .. max-1 */
347}
348#endif /* READ_TRANSFORMS || WRITE_FILTER */
349
350#if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\
351 (defined PNG_READ_FILLER_SUPPORTED)
352static int
353random_choice(void)
354{
355 return random_byte() & 1;
356}
357#endif /* READ_RGB_TO_GRAY || READ_FILLER */
358
359/* A numeric ID based on PNG file characteristics. The 'do_interlace' field
360 * simply records whether pngvalid did the interlace itself or whether it
361 * was done by libpng. Width and height must be less than 256. 'palette' is an
362 * index of the palette to use for formats with a palette otherwise a boolean
363 * indicating if a tRNS chunk was generated.
364 */
365#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
366 ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
367 (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
368
369#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
370#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
371#define PALETTE_FROM_ID(id) (((id) >> 8) & 0x1f)
372#define INTERLACE_FROM_ID(id) ((png_byte)(((id) >> 13) & 0x3))
373#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
374#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
375#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
376
377/* Utility to construct a standard name for a standard image. */
378static size_t
379standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
380 int bit_depth, unsigned int npalette, int interlace_type,
381 png_uint_32 w, png_uint_32 h, int do_interlace)
382{
383 pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
384 if (colour_type == 3) /* must have a palette */
385 {
386 pos = safecat(buffer, bufsize, pos, "[");
387 pos = safecatn(buffer, bufsize, pos, npalette);
388 pos = safecat(buffer, bufsize, pos, "]");
389 }
390
391 else if (npalette != 0)
392 pos = safecat(buffer, bufsize, pos, "+tRNS");
393
394 pos = safecat(buffer, bufsize, pos, " ");
395 pos = safecatn(buffer, bufsize, pos, bit_depth);
396 pos = safecat(buffer, bufsize, pos, " bit");
397
398 if (interlace_type != PNG_INTERLACE_NONE)
399 {
400 pos = safecat(buffer, bufsize, pos, " interlaced");
401 if (do_interlace)
402 pos = safecat(buffer, bufsize, pos, "(pngvalid)");
403 else
404 pos = safecat(buffer, bufsize, pos, "(libpng)");
405 }
406
407 if (w > 0 || h > 0)
408 {
409 pos = safecat(buffer, bufsize, pos, " ");
410 pos = safecatn(buffer, bufsize, pos, w);
411 pos = safecat(buffer, bufsize, pos, "x");
412 pos = safecatn(buffer, bufsize, pos, h);
413 }
414
415 return pos;
416}
417
418static size_t
419standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
420{
421 return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
422 DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
423 WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
424}
425
426/* Convenience API and defines to list valid formats. Note that 16 bit read and
427 * write support is required to do 16 bit read tests (we must be able to make a
428 * 16 bit image to test!)
429 */
430#ifdef PNG_WRITE_16BIT_SUPPORTED
431# define WRITE_BDHI 4
432# ifdef PNG_READ_16BIT_SUPPORTED
433# define READ_BDHI 4
434# define DO_16BIT
435# endif
436#else
437# define WRITE_BDHI 3
438#endif
439#ifndef DO_16BIT
440# define READ_BDHI 3
441#endif
442
443/* The following defines the number of different palettes to generate for
444 * each log bit depth of a colour type 3 standard image.
445 */
446#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1U : 16U)
447
448static int
449next_format(png_bytep colour_type, png_bytep bit_depth,
450 unsigned int* palette_number, int low_depth_gray, int tRNS)
451{
452 if (*bit_depth == 0)
453 {
454 *colour_type = 0;
455 if (low_depth_gray)
456 *bit_depth = 1;
457 else
458 *bit_depth = 8;
459 *palette_number = 0;
460 return 1;
461 }
462
463 if (*colour_type < 4/*no alpha channel*/)
464 {
465 /* Add multiple palettes for colour type 3, one image with tRNS
466 * and one without for other non-alpha formats:
467 */
468 unsigned int pn = ++*palette_number;
469 png_byte ct = *colour_type;
470
471 if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) ||
472 (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth)))
473 return 1;
474
475 /* No: next bit depth */
476 *palette_number = 0;
477 }
478
479 *bit_depth = (png_byte)(*bit_depth << 1);
480
481 /* Palette images are restricted to 8 bit depth */
482 if (*bit_depth <= 8
483#ifdef DO_16BIT
484 || (*colour_type != 3 && *bit_depth <= 16)
485#endif
486 )
487 return 1;
488
489 /* Move to the next color type, or return 0 at the end. */
490 switch (*colour_type)
491 {
492 case 0:
493 *colour_type = 2;
494 *bit_depth = 8;
495 return 1;
496
497 case 2:
498 *colour_type = 3;
499 *bit_depth = 1;
500 return 1;
501
502 case 3:
503 *colour_type = 4;
504 *bit_depth = 8;
505 return 1;
506
507 case 4:
508 *colour_type = 6;
509 *bit_depth = 8;
510 return 1;
511
512 default:
513 return 0;
514 }
515}
516
517#ifdef PNG_READ_TRANSFORMS_SUPPORTED
518static unsigned int
519sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
520 png_uint_32 x, unsigned int sample_index, int swap16, int littleendian)
521{
522 png_uint_32 bit_index, result;
523
524 /* Find a sample index for the desired sample: */
525 x *= bit_depth;
526 bit_index = x;
527
528 if ((colour_type & 1) == 0) /* !palette */
529 {
530 if (colour_type & 2)
531 bit_index *= 3;
532
533 if (colour_type & 4)
534 bit_index += x; /* Alpha channel */
535
536 /* Multiple channels; select one: */
537 if (colour_type & (2+4))
538 bit_index += sample_index * bit_depth;
539 }
540
541 /* Return the sample from the row as an integer. */
542 row += bit_index >> 3;
543 result = *row;
544
545 if (bit_depth == 8)
546 return result;
547
548 else if (bit_depth > 8)
549 {
550 if (swap16)
551 return (*++row << 8) + result;
552 else
553 return (result << 8) + *++row;
554 }
555
556 /* Less than 8 bits per sample. By default PNG has the big end of
557 * the egg on the left of the screen, but if littleendian is set
558 * then the big end is on the right.
559 */
560 bit_index &= 7;
561
562 if (!littleendian)
563 bit_index = 8-bit_index-bit_depth;
564
565 return (result >> bit_index) & ((1U<<bit_depth)-1);
566}
567#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
568
569/* Copy a single pixel, of a given size, from one buffer to another -
570 * while this is basically bit addressed there is an implicit assumption
571 * that pixels 8 or more bits in size are byte aligned and that pixels
572 * do not otherwise cross byte boundaries. (This is, so far as I know,
573 * universally true in bitmap computer graphics. [JCB 20101212])
574 *
575 * NOTE: The to and from buffers may be the same.
576 */
577static void
578pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
579 png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize,
580 int littleendian)
581{
582 /* Assume we can multiply by 'size' without overflow because we are
583 * just working in a single buffer.
584 */
585 toIndex *= pixelSize;
586 fromIndex *= pixelSize;
587 if (pixelSize < 8) /* Sub-byte */
588 {
589 /* Mask to select the location of the copied pixel: */
590 unsigned int destMask = ((1U<<pixelSize)-1) <<
591 (littleendian ? toIndex&7 : 8-pixelSize-(toIndex&7));
592 /* The following read the entire pixels and clears the extra: */
593 unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
594 unsigned int sourceByte = fromBuffer[fromIndex >> 3];
595
596 /* Don't rely on << or >> supporting '0' here, just in case: */
597 fromIndex &= 7;
598 if (littleendian)
599 {
600 if (fromIndex > 0) sourceByte >>= fromIndex;
601 if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7;
602 }
603
604 else
605 {
606 if (fromIndex > 0) sourceByte <<= fromIndex;
607 if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
608 }
609
610 toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
611 }
612 else /* One or more bytes */
613 memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
614}
615
616#ifdef PNG_READ_SUPPORTED
617/* Copy a complete row of pixels, taking into account potential partial
618 * bytes at the end.
619 */
620static void
621row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth,
622 int littleendian)
623{
624 memcpy(toBuffer, fromBuffer, bitWidth >> 3);
625
626 if ((bitWidth & 7) != 0)
627 {
628 unsigned int mask;
629
630 toBuffer += bitWidth >> 3;
631 fromBuffer += bitWidth >> 3;
632 if (littleendian)
633 mask = 0xff << (bitWidth & 7);
634 else
635 mask = 0xff >> (bitWidth & 7);
636 *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
637 }
638}
639
640/* Compare pixels - they are assumed to start at the first byte in the
641 * given buffers.
642 */
643static int
644pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
645{
646#if PNG_LIBPNG_VER < 10506
647 if (memcmp(pa, pb, bit_width>>3) == 0)
648 {
649 png_uint_32 p;
650
651 if ((bit_width & 7) == 0) return 0;
652
653 /* Ok, any differences? */
654 p = pa[bit_width >> 3];
655 p ^= pb[bit_width >> 3];
656
657 if (p == 0) return 0;
658
659 /* There are, but they may not be significant, remove the bits
660 * after the end (the low order bits in PNG.)
661 */
662 bit_width &= 7;
663 p >>= 8-bit_width;
664
665 if (p == 0) return 0;
666 }
667#else
668 /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
669 * bits too:
670 */
671 if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
672 return 0;
673#endif
674
675 /* Return the index of the changed byte. */
676 {
677 png_uint_32 where = 0;
678
679 while (pa[where] == pb[where]) ++where;
680 return 1+where;
681 }
682}
683#endif /* PNG_READ_SUPPORTED */
684
685/*************************** BASIC PNG FILE WRITING ***************************/
686/* A png_store takes data from the sequential writer or provides data
687 * to the sequential reader. It can also store the result of a PNG
688 * write for later retrieval.
689 */
690#define STORE_BUFFER_SIZE 500 /* arbitrary */
691typedef struct png_store_buffer
692{
693 struct png_store_buffer* prev; /* NOTE: stored in reverse order */
694 png_byte buffer[STORE_BUFFER_SIZE];
695} png_store_buffer;
696
697#define FILE_NAME_SIZE 64
698
699typedef struct store_palette_entry /* record of a single palette entry */
700{
701 png_byte red;
702 png_byte green;
703 png_byte blue;
704 png_byte alpha;
705} store_palette_entry, store_palette[256];
706
707typedef struct png_store_file
708{
709 struct png_store_file* next; /* as many as you like... */
710 char name[FILE_NAME_SIZE];
711 unsigned int IDAT_bits; /* Number of bits in IDAT size */
712 png_uint_32 IDAT_size; /* Total size of IDAT data */
713 png_uint_32 id; /* must be correct (see FILEID) */
714 png_size_t datacount; /* In this (the last) buffer */
715 png_store_buffer data; /* Last buffer in file */
716 int npalette; /* Number of entries in palette */
717 store_palette_entry* palette; /* May be NULL */
718} png_store_file;
719
720/* The following is a pool of memory allocated by a single libpng read or write
721 * operation.
722 */
723typedef struct store_pool
724{
725 struct png_store *store; /* Back pointer */
726 struct store_memory *list; /* List of allocated memory */
727 png_byte mark[4]; /* Before and after data */
728
729 /* Statistics for this run. */
730 png_alloc_size_t max; /* Maximum single allocation */
731 png_alloc_size_t current; /* Current allocation */
732 png_alloc_size_t limit; /* Highest current allocation */
733 png_alloc_size_t total; /* Total allocation */
734
735 /* Overall statistics (retained across successive runs). */
736 png_alloc_size_t max_max;
737 png_alloc_size_t max_limit;
738 png_alloc_size_t max_total;
739} store_pool;
740
741typedef struct png_store
742{
743 /* For cexcept.h exception handling - simply store one of these;
744 * the context is a self pointer but it may point to a different
745 * png_store (in fact it never does in this program.)
746 */
747 struct exception_context
748 exception_context;
749
750 unsigned int verbose :1;
751 unsigned int treat_warnings_as_errors :1;
752 unsigned int expect_error :1;
753 unsigned int expect_warning :1;
754 unsigned int saw_warning :1;
755 unsigned int speed :1;
756 unsigned int progressive :1; /* use progressive read */
757 unsigned int validated :1; /* used as a temporary flag */
758 int nerrors;
759 int nwarnings;
760 int noptions; /* number of options below: */
761 struct {
762 unsigned char option; /* option number, 0..30 */
763 unsigned char setting; /* setting (unset,invalid,on,off) */
764 } options[16];
765 char test[128]; /* Name of test */
766 char error[256];
767
768 /* Share fields */
769 png_uint_32 chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
770 png_uint_32 chunktype;/* Type of chunk (valid if chunkpos >= 4) */
771 png_uint_32 chunkpos; /* Position in chunk */
772 png_uint_32 IDAT_size;/* Accumulated IDAT size in .new */
773 unsigned int IDAT_bits;/* Cache of the file store value */
774
775 /* Read fields */
776 png_structp pread; /* Used to read a saved file */
777 png_infop piread;
778 png_store_file* current; /* Set when reading */
779 png_store_buffer* next; /* Set when reading */
780 png_size_t readpos; /* Position in *next */
781 png_byte* image; /* Buffer for reading interlaced images */
782 png_size_t cb_image; /* Size of this buffer */
783 png_size_t cb_row; /* Row size of the image(s) */
784 uLong IDAT_crc;
785 png_uint_32 IDAT_len; /* Used when re-chunking IDAT chunks */
786 png_uint_32 IDAT_pos; /* Used when re-chunking IDAT chunks */
787 png_uint_32 image_h; /* Number of rows in a single image */
788 store_pool read_memory_pool;
789
790 /* Write fields */
791 png_store_file* saved;
792 png_structp pwrite; /* Used when writing a new file */
793 png_infop piwrite;
794 png_size_t writepos; /* Position in .new */
795 char wname[FILE_NAME_SIZE];
796 png_store_buffer new; /* The end of the new PNG file being written. */
797 store_pool write_memory_pool;
798 store_palette_entry* palette;
799 int npalette;
800} png_store;
801
802/* Initialization and cleanup */
803static void
804store_pool_mark(png_bytep mark)
805{
806 static png_uint_32 store_seed[2] = { 0x12345678, 1};
807
808 make_four_random_bytes(store_seed, mark);
809}
810
811#ifdef PNG_READ_TRANSFORMS_SUPPORTED
812/* Use this for random 32 bit values; this function makes sure the result is
813 * non-zero.
814 */
815static png_uint_32
816random_32(void)
817{
818
819 for (;;)
820 {
821 png_byte mark[4];
822 png_uint_32 result;
823
824 store_pool_mark(mark);
825 result = png_get_uint_32(mark);
826
827 if (result != 0)
828 return result;
829 }
830}
831#endif /* PNG_READ_SUPPORTED */
832
833static void
834store_pool_init(png_store *ps, store_pool *pool)
835{
836 memset(pool, 0, sizeof *pool);
837
838 pool->store = ps;
839 pool->list = NULL;
840 pool->max = pool->current = pool->limit = pool->total = 0;
841 pool->max_max = pool->max_limit = pool->max_total = 0;
842 store_pool_mark(pool->mark);
843}
844
845static void
846store_init(png_store* ps)
847{
848 memset(ps, 0, sizeof *ps);
849 init_exception_context(&ps->exception_context);
850 store_pool_init(ps, &ps->read_memory_pool);
851 store_pool_init(ps, &ps->write_memory_pool);
852 ps->verbose = 0;
853 ps->treat_warnings_as_errors = 0;
854 ps->expect_error = 0;
855 ps->expect_warning = 0;
856 ps->saw_warning = 0;
857 ps->speed = 0;
858 ps->progressive = 0;
859 ps->validated = 0;
860 ps->nerrors = ps->nwarnings = 0;
861 ps->pread = NULL;
862 ps->piread = NULL;
863 ps->saved = ps->current = NULL;
864 ps->next = NULL;
865 ps->readpos = 0;
866 ps->image = NULL;
867 ps->cb_image = 0;
868 ps->cb_row = 0;
869 ps->image_h = 0;
870 ps->pwrite = NULL;
871 ps->piwrite = NULL;
872 ps->writepos = 0;
873 ps->chunkpos = 8;
874 ps->chunktype = 0;
875 ps->chunklen = 16;
876 ps->IDAT_size = 0;
877 ps->IDAT_bits = 0;
878 ps->new.prev = NULL;
879 ps->palette = NULL;
880 ps->npalette = 0;
881 ps->noptions = 0;
882}
883
884static void
885store_freebuffer(png_store_buffer* psb)
886{
887 if (psb->prev)
888 {
889 store_freebuffer(psb->prev);
890 free(psb->prev);
891 psb->prev = NULL;
892 }
893}
894
895static void
896store_freenew(png_store *ps)
897{
898 store_freebuffer(&ps->new);
899 ps->writepos = 0;
900 ps->chunkpos = 8;
901 ps->chunktype = 0;
902 ps->chunklen = 16;
903 ps->IDAT_size = 0;
904 ps->IDAT_bits = 0;
905 if (ps->palette != NULL)
906 {
907 free(ps->palette);
908 ps->palette = NULL;
909 ps->npalette = 0;
910 }
911}
912
913static void
914store_storenew(png_store *ps)
915{
916 png_store_buffer *pb;
917
918 pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
919
920 if (pb == NULL)
921 png_error(ps->pwrite, "store new: OOM");
922
923 *pb = ps->new;
924 ps->new.prev = pb;
925 ps->writepos = 0;
926}
927
928static void
929store_freefile(png_store_file **ppf)
930{
931 if (*ppf != NULL)
932 {
933 store_freefile(&(*ppf)->next);
934
935 store_freebuffer(&(*ppf)->data);
936 (*ppf)->datacount = 0;
937 if ((*ppf)->palette != NULL)
938 {
939 free((*ppf)->palette);
940 (*ppf)->palette = NULL;
941 (*ppf)->npalette = 0;
942 }
943 free(*ppf);
944 *ppf = NULL;
945 }
946}
947
948static unsigned int
949bits_of(png_uint_32 num)
950{
951 /* Return the number of bits in 'num' */
952 unsigned int b = 0;
953
954 if (num & 0xffff0000U) b += 16U, num >>= 16;
955 if (num & 0xff00U) b += 8U, num >>= 8;
956 if (num & 0xf0U) b += 4U, num >>= 4;
957 if (num & 0xcU) b += 2U, num >>= 2;
958 if (num & 0x2U) ++b, num >>= 1;
959 if (num) ++b;
960
961 return b; /* 0..32 */
962}
963
964/* Main interface to file storeage, after writing a new PNG file (see the API
965 * below) call store_storefile to store the result with the given name and id.
966 */
967static void
968store_storefile(png_store *ps, png_uint_32 id)
969{
970 png_store_file *pf;
971
972 if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
973 ps->IDAT_size == 0)
974 png_error(ps->pwrite, "storefile: incomplete write");
975
976 pf = voidcast(png_store_file*, malloc(sizeof *pf));
977 if (pf == NULL)
978 png_error(ps->pwrite, "storefile: OOM");
979 safecat(pf->name, sizeof pf->name, 0, ps->wname);
980 pf->id = id;
981 pf->data = ps->new;
982 pf->datacount = ps->writepos;
983 pf->IDAT_size = ps->IDAT_size;
984 pf->IDAT_bits = bits_of(ps->IDAT_size);
985 /* Because the IDAT always has zlib header stuff this must be true: */
986 if (pf->IDAT_bits == 0U)
987 png_error(ps->pwrite, "storefile: 0 sized IDAT");
988 ps->new.prev = NULL;
989 ps->writepos = 0;
990 ps->chunkpos = 8;
991 ps->chunktype = 0;
992 ps->chunklen = 16;
993 ps->IDAT_size = 0;
994 pf->palette = ps->palette;
995 pf->npalette = ps->npalette;
996 ps->palette = 0;
997 ps->npalette = 0;
998
999 /* And save it. */
1000 pf->next = ps->saved;
1001 ps->saved = pf;
1002}
1003
1004/* Generate an error message (in the given buffer) */
1005static size_t
1006store_message(png_store *ps, png_const_structp pp, char *buffer, size_t bufsize,
1007 size_t pos, const char *msg)
1008{
1009 if (pp != NULL && pp == ps->pread)
1010 {
1011 /* Reading a file */
1012 pos = safecat(buffer, bufsize, pos, "read: ");
1013
1014 if (ps->current != NULL)
1015 {
1016 pos = safecat(buffer, bufsize, pos, ps->current->name);
1017 pos = safecat(buffer, bufsize, pos, sep);
1018 }
1019 }
1020
1021 else if (pp != NULL && pp == ps->pwrite)
1022 {
1023 /* Writing a file */
1024 pos = safecat(buffer, bufsize, pos, "write: ");
1025 pos = safecat(buffer, bufsize, pos, ps->wname);
1026 pos = safecat(buffer, bufsize, pos, sep);
1027 }
1028
1029 else
1030 {
1031 /* Neither reading nor writing (or a memory error in struct delete) */
1032 pos = safecat(buffer, bufsize, pos, "pngvalid: ");
1033 }
1034
1035 if (ps->test[0] != 0)
1036 {
1037 pos = safecat(buffer, bufsize, pos, ps->test);
1038 pos = safecat(buffer, bufsize, pos, sep);
1039 }
1040 pos = safecat(buffer, bufsize, pos, msg);
1041 return pos;
1042}
1043
1044/* Verbose output to the error stream: */
1045static void
1046store_verbose(png_store *ps, png_const_structp pp, png_const_charp prefix,
1047 png_const_charp message)
1048{
1049 char buffer[512];
1050
1051 if (prefix)
1052 fputs(prefix, stderr);
1053
1054 (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
1055 fputs(buffer, stderr);
1056 fputc('\n', stderr);
1057}
1058
1059/* Log an error or warning - the relevant count is always incremented. */
1060static void
1061store_log(png_store* ps, png_const_structp pp, png_const_charp message,
1062 int is_error)
1063{
1064 /* The warning is copied to the error buffer if there are no errors and it is
1065 * the first warning. The error is copied to the error buffer if it is the
1066 * first error (overwriting any prior warnings).
1067 */
1068 if (is_error ? (ps->nerrors)++ == 0 :
1069 (ps->nwarnings)++ == 0 && ps->nerrors == 0)
1070 store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
1071
1072 if (ps->verbose)
1073 store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
1074}
1075
1076#ifdef PNG_READ_SUPPORTED
1077/* Internal error function, called with a png_store but no libpng stuff. */
1078static void
1079internal_error(png_store *ps, png_const_charp message)
1080{
1081 store_log(ps, NULL, message, 1 /* error */);
1082
1083 /* And finally throw an exception. */
1084 {
1085 struct exception_context *the_exception_context = &ps->exception_context;
1086 Throw ps;
1087 }
1088}
1089#endif /* PNG_READ_SUPPORTED */
1090
1091/* Functions to use as PNG callbacks. */
1092static void PNGCBAPI
1093store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
1094{
1095 png_const_structp pp = ppIn;
1096 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1097
1098 if (!ps->expect_error)
1099 store_log(ps, pp, message, 1 /* error */);
1100
1101 /* And finally throw an exception. */
1102 {
1103 struct exception_context *the_exception_context = &ps->exception_context;
1104 Throw ps;
1105 }
1106}
1107
1108static void PNGCBAPI
1109store_warning(png_structp ppIn, png_const_charp message)
1110{
1111 png_const_structp pp = ppIn;
1112 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1113
1114 if (!ps->expect_warning)
1115 store_log(ps, pp, message, 0 /* warning */);
1116 else
1117 ps->saw_warning = 1;
1118}
1119
1120/* These somewhat odd functions are used when reading an image to ensure that
1121 * the buffer is big enough, the png_structp is for errors.
1122 */
1123/* Return a single row from the correct image. */
1124static png_bytep
1125store_image_row(const png_store* ps, png_const_structp pp, int nImage,
1126 png_uint_32 y)
1127{
1128 png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
1129
1130 if (ps->image == NULL)
1131 png_error(pp, "no allocated image");
1132
1133 if (coffset + ps->cb_row + 3 > ps->cb_image)
1134 png_error(pp, "image too small");
1135
1136 return ps->image + coffset;
1137}
1138
1139static void
1140store_image_free(png_store *ps, png_const_structp pp)
1141{
1142 if (ps->image != NULL)
1143 {
1144 png_bytep image = ps->image;
1145
1146 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1147 {
1148 if (pp != NULL)
1149 png_error(pp, "png_store image overwrite (1)");
1150 else
1151 store_log(ps, NULL, "png_store image overwrite (2)", 1);
1152 }
1153
1154 ps->image = NULL;
1155 ps->cb_image = 0;
1156 --image;
1157 free(image);
1158 }
1159}
1160
1161static void
1162store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
1163 png_size_t cbRow, png_uint_32 cRows)
1164{
1165 png_size_t cb = nImages * cRows * (cbRow + 5);
1166
1167 if (ps->cb_image < cb)
1168 {
1169 png_bytep image;
1170
1171 store_image_free(ps, pp);
1172
1173 /* The buffer is deliberately mis-aligned. */
1174 image = voidcast(png_bytep, malloc(cb+2));
1175 if (image == NULL)
1176 {
1177 /* Called from the startup - ignore the error for the moment. */
1178 if (pp == NULL)
1179 return;
1180
1181 png_error(pp, "OOM allocating image buffer");
1182 }
1183
1184 /* These magic tags are used to detect overwrites above. */
1185 ++image;
1186 image[-1] = 0xed;
1187 image[cb] = 0xfe;
1188
1189 ps->image = image;
1190 ps->cb_image = cb;
1191 }
1192
1193 /* We have an adequate sized image; lay out the rows. There are 2 bytes at
1194 * the start and three at the end of each (this ensures that the row
1195 * alignment starts out odd - 2+1 and changes for larger images on each row.)
1196 */
1197 ps->cb_row = cbRow;
1198 ps->image_h = cRows;
1199
1200 /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
1201 * This deliberately doesn't match the bits in the size test image which are
1202 * outside the image; these are set to 0xff (all 1). To make the row
1203 * comparison work in the 'size' test case the size rows are pre-initialized
1204 * to the same value prior to calling 'standard_row'.
1205 */
1206 memset(ps->image, 178, cb);
1207
1208 /* Then put in the marks. */
1209 while (--nImages >= 0)
1210 {
1211 png_uint_32 y;
1212
1213 for (y=0; y<cRows; ++y)
1214 {
1215 png_bytep row = store_image_row(ps, pp, nImages, y);
1216
1217 /* The markers: */
1218 row[-2] = 190;
1219 row[-1] = 239;
1220 row[cbRow] = 222;
1221 row[cbRow+1] = 173;
1222 row[cbRow+2] = 17;
1223 }
1224 }
1225}
1226
1227#ifdef PNG_READ_SUPPORTED
1228static void
1229store_image_check(const png_store* ps, png_const_structp pp, int iImage)
1230{
1231 png_const_bytep image = ps->image;
1232
1233 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1234 png_error(pp, "image overwrite");
1235 else
1236 {
1237 png_size_t cbRow = ps->cb_row;
1238 png_uint_32 rows = ps->image_h;
1239
1240 image += iImage * (cbRow+5) * ps->image_h;
1241
1242 image += 2; /* skip image first row markers */
1243
1244 for (; rows > 0; --rows)
1245 {
1246 if (image[-2] != 190 || image[-1] != 239)
1247 png_error(pp, "row start overwritten");
1248
1249 if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
1250 image[cbRow+2] != 17)
1251 png_error(pp, "row end overwritten");
1252
1253 image += cbRow+5;
1254 }
1255 }
1256}
1257#endif /* PNG_READ_SUPPORTED */
1258
1259static int
1260valid_chunktype(png_uint_32 chunktype)
1261{
1262 /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
1263 * (both inclusive), so:
1264 */
1265 unsigned int i;
1266
1267 for (i=0; i<4; ++i)
1268 {
1269 unsigned int c = chunktype & 0xffU;
1270
1271 if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
1272 return 0;
1273
1274 chunktype >>= 8;
1275 }
1276
1277 return 1; /* It's valid */
1278}
1279
1280static void PNGCBAPI
1281store_write(png_structp ppIn, png_bytep pb, png_size_t st)
1282{
1283 png_const_structp pp = ppIn;
1284 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1285 size_t writepos = ps->writepos;
1286 png_uint_32 chunkpos = ps->chunkpos;
1287 png_uint_32 chunktype = ps->chunktype;
1288 png_uint_32 chunklen = ps->chunklen;
1289
1290 if (ps->pwrite != pp)
1291 png_error(pp, "store state damaged");
1292
1293 /* Technically this is legal, but in practice libpng never writes more than
1294 * the maximum chunk size at once so if it happens something weird has
1295 * changed inside libpng (probably).
1296 */
1297 if (st > 0x7fffffffU)
1298 png_error(pp, "unexpected write size");
1299
1300 /* Now process the bytes to be written. Do this in units of the space in the
1301 * output (write) buffer or, at the start 4 bytes for the chunk type and
1302 * length limited in any case by the amount of data.
1303 */
1304 while (st > 0)
1305 {
1306 if (writepos >= STORE_BUFFER_SIZE)
1307 store_storenew(ps), writepos = 0;
1308
1309 if (chunkpos < 4)
1310 {
1311 png_byte b = *pb++;
1312 --st;
1313 chunklen = (chunklen << 8) + b;
1314 ps->new.buffer[writepos++] = b;
1315 ++chunkpos;
1316 }
1317
1318 else if (chunkpos < 8)
1319 {
1320 png_byte b = *pb++;
1321 --st;
1322 chunktype = (chunktype << 8) + b;
1323 ps->new.buffer[writepos++] = b;
1324
1325 if (++chunkpos == 8)
1326 {
1327 chunklen &= 0xffffffffU;
1328 if (chunklen > 0x7fffffffU)
1329 png_error(pp, "chunk length too great");
1330
1331 chunktype &= 0xffffffffU;
1332 if (chunktype == CHUNK_IDAT)
1333 {
1334 if (chunklen > ~ps->IDAT_size)
1335 png_error(pp, "pngvalid internal image too large");
1336
1337 ps->IDAT_size += chunklen;
1338 }
1339
1340 else if (!valid_chunktype(chunktype))
1341 png_error(pp, "invalid chunk type");
1342
1343 chunklen += 12; /* for header and CRC */
1344 }
1345 }
1346
1347 else /* chunkpos >= 8 */
1348 {
1349 png_size_t cb = st;
1350
1351 if (cb > STORE_BUFFER_SIZE - writepos)
1352 cb = STORE_BUFFER_SIZE - writepos;
1353
1354 if (cb > chunklen - chunkpos/* bytes left in chunk*/)
1355 cb = (png_size_t)/*SAFE*/(chunklen - chunkpos);
1356
1357 memcpy(ps->new.buffer + writepos, pb, cb);
1358 chunkpos += (png_uint_32)/*SAFE*/cb;
1359 pb += cb;
1360 writepos += cb;
1361 st -= cb;
1362
1363 if (chunkpos >= chunklen) /* must be equal */
1364 chunkpos = chunktype = chunklen = 0;
1365 }
1366 } /* while (st > 0) */
1367
1368 ps->writepos = writepos;
1369 ps->chunkpos = chunkpos;
1370 ps->chunktype = chunktype;
1371 ps->chunklen = chunklen;
1372}
1373
1374static void PNGCBAPI
1375store_flush(png_structp ppIn)
1376{
1377 UNUSED(ppIn) /*DOES NOTHING*/
1378}
1379
1380#ifdef PNG_READ_SUPPORTED
1381static size_t
1382store_read_buffer_size(png_store *ps)
1383{
1384 /* Return the bytes available for read in the current buffer. */
1385 if (ps->next != &ps->current->data)
1386 return STORE_BUFFER_SIZE;
1387
1388 return ps->current->datacount;
1389}
1390
1391/* Return total bytes available for read. */
1392static size_t
1393store_read_buffer_avail(png_store *ps)
1394{
1395 if (ps->current != NULL && ps->next != NULL)
1396 {
1397 png_store_buffer *next = &ps->current->data;
1398 size_t cbAvail = ps->current->datacount;
1399
1400 while (next != ps->next && next != NULL)
1401 {
1402 next = next->prev;
1403 cbAvail += STORE_BUFFER_SIZE;
1404 }
1405
1406 if (next != ps->next)
1407 png_error(ps->pread, "buffer read error");
1408
1409 if (cbAvail > ps->readpos)
1410 return cbAvail - ps->readpos;
1411 }
1412
1413 return 0;
1414}
1415
1416static int
1417store_read_buffer_next(png_store *ps)
1418{
1419 png_store_buffer *pbOld = ps->next;
1420 png_store_buffer *pbNew = &ps->current->data;
1421 if (pbOld != pbNew)
1422 {
1423 while (pbNew != NULL && pbNew->prev != pbOld)
1424 pbNew = pbNew->prev;
1425
1426 if (pbNew != NULL)
1427 {
1428 ps->next = pbNew;
1429 ps->readpos = 0;
1430 return 1;
1431 }
1432
1433 png_error(ps->pread, "buffer lost");
1434 }
1435
1436 return 0; /* EOF or error */
1437}
1438
1439/* Need separate implementation and callback to allow use of the same code
1440 * during progressive read, where the io_ptr is set internally by libpng.
1441 */
1442static void
1443store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
1444{
1445 if (ps->current == NULL || ps->next == NULL)
1446 png_error(ps->pread, "store state damaged");
1447
1448 while (st > 0)
1449 {
1450 size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
1451
1452 if (cbAvail > 0)
1453 {
1454 if (cbAvail > st) cbAvail = st;
1455 memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
1456 st -= cbAvail;
1457 pb += cbAvail;
1458 ps->readpos += cbAvail;
1459 }
1460
1461 else if (!store_read_buffer_next(ps))
1462 png_error(ps->pread, "read beyond end of file");
1463 }
1464}
1465
1466static png_size_t
1467store_read_chunk(png_store *ps, png_bytep pb, const png_size_t max,
1468 const png_size_t min)
1469{
1470 png_uint_32 chunklen = ps->chunklen;
1471 png_uint_32 chunktype = ps->chunktype;
1472 png_uint_32 chunkpos = ps->chunkpos;
1473 png_size_t st = max;
1474
1475 if (st > 0) do
1476 {
1477 if (chunkpos >= chunklen) /* end of last chunk */
1478 {
1479 png_byte buffer[8];
1480
1481 /* Read the header of the next chunk: */
1482 store_read_imp(ps, buffer, 8U);
1483 chunklen = png_get_uint_32(buffer) + 12U;
1484 chunktype = png_get_uint_32(buffer+4U);
1485 chunkpos = 0U; /* Position read so far */
1486 }
1487
1488 if (chunktype == CHUNK_IDAT)
1489 {
1490 png_uint_32 IDAT_pos = ps->IDAT_pos;
1491 png_uint_32 IDAT_len = ps->IDAT_len;
1492 png_uint_32 IDAT_size = ps->IDAT_size;
1493
1494 /* The IDAT headers are constructed here; skip the input header. */
1495 if (chunkpos < 8U)
1496 chunkpos = 8U;
1497
1498 if (IDAT_pos == IDAT_len)
1499 {
1500 png_byte random = random_byte();
1501
1502 /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
1503 * if IDAT_size is 0 this is the end. At present this is set up
1504 * using a random number so that there is a 25% chance before
1505 * the start of the first IDAT chunk being 0 length.
1506 */
1507 if (IDAT_len == 0U) /* First IDAT */
1508 {
1509 switch (random & 3U)
1510 {
1511 case 0U: IDAT_len = 12U; break; /* 0 bytes */
1512 case 1U: IDAT_len = 13U; break; /* 1 byte */
1513 default: IDAT_len = random_u32();
1514 IDAT_len %= IDAT_size;
1515 IDAT_len += 13U; /* 1..IDAT_size bytes */
1516 break;
1517 }
1518 }
1519
1520 else if (IDAT_size == 0U) /* all IDAT data read */
1521 {
1522 /* The last (IDAT) chunk should be positioned at the CRC now: */
1523 if (chunkpos != chunklen-4U)
1524 png_error(ps->pread, "internal: IDAT size mismatch");
1525
1526 /* The only option here is to add a zero length IDAT, this
1527 * happens 25% of the time. Because of the check above
1528 * chunklen-4U-chunkpos must be zero, we just need to skip the
1529 * CRC now.
1530 */
1531 if ((random & 3U) == 0U)
1532 IDAT_len = 12U; /* Output another 0 length IDAT */
1533
1534 else
1535 {
1536 /* End of IDATs, skip the CRC to make the code above load the
1537 * next chunk header next time round.
1538 */
1539 png_byte buffer[4];
1540
1541 store_read_imp(ps, buffer, 4U);
1542 chunkpos += 4U;
1543 ps->IDAT_pos = IDAT_pos;
1544 ps->IDAT_len = IDAT_len;
1545 ps->IDAT_size = 0U;
1546 continue; /* Read the next chunk */
1547 }
1548 }
1549
1550 else
1551 {
1552 /* Middle of IDATs, use 'random' to determine the number of bits
1553 * to use in the IDAT length.
1554 */
1555 IDAT_len = random_u32();
1556 IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
1557 if (IDAT_len > IDAT_size)
1558 IDAT_len = IDAT_size;
1559 IDAT_len += 12U; /* zero bytes may occur */
1560 }
1561
1562 IDAT_pos = 0U;
1563 ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
1564 } /* IDAT_pos == IDAT_len */
1565
1566 if (IDAT_pos < 8U) /* Return the header */ do
1567 {
1568 png_uint_32 b;
1569 unsigned int shift;
1570
1571 if (IDAT_pos < 4U)
1572 b = IDAT_len - 12U;
1573
1574 else
1575 b = CHUNK_IDAT;
1576
1577 shift = 3U & IDAT_pos;
1578 ++IDAT_pos;
1579
1580 if (shift < 3U)
1581 b >>= 8U*(3U-shift);
1582
1583 *pb++ = 0xffU & b;
1584 }
1585 while (--st > 0 && IDAT_pos < 8);
1586
1587 else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
1588 {
1589 if (chunkpos < chunklen-4U)
1590 {
1591 uInt avail = (uInt)-1;
1592
1593 if (avail > (IDAT_len-4U) - IDAT_pos)
1594 avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
1595
1596 if (avail > st)
1597 avail = (uInt)/*SAFE*/st;
1598
1599 if (avail > (chunklen-4U) - chunkpos)
1600 avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
1601
1602 store_read_imp(ps, pb, avail);
1603 ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
1604 pb += (png_size_t)/*SAFE*/avail;
1605 st -= (png_size_t)/*SAFE*/avail;
1606 chunkpos += (png_uint_32)/*SAFE*/avail;
1607 IDAT_size -= (png_uint_32)/*SAFE*/avail;
1608 IDAT_pos += (png_uint_32)/*SAFE*/avail;
1609 }
1610
1611 else /* skip the input CRC */
1612 {
1613 png_byte buffer[4];
1614
1615 store_read_imp(ps, buffer, 4U);
1616 chunkpos += 4U;
1617 }
1618 }
1619
1620 else /* IDAT crc */ do
1621 {
1622 uLong b = ps->IDAT_crc;
1623 unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
1624 ++IDAT_pos;
1625
1626 if (shift > 1U)
1627 b >>= 8U*(shift-1U);
1628
1629 *pb++ = 0xffU & b;
1630 }
1631 while (--st > 0 && IDAT_pos < IDAT_len);
1632
1633 ps->IDAT_pos = IDAT_pos;
1634 ps->IDAT_len = IDAT_len;
1635 ps->IDAT_size = IDAT_size;
1636 }
1637
1638 else /* !IDAT */
1639 {
1640 /* If there is still some pending IDAT data after the IDAT chunks have
1641 * been processed there is a problem:
1642 */
1643 if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
1644 png_error(ps->pread, "internal: missing IDAT data");
1645
1646 if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
1647 png_error(ps->pread, "internal: missing IDAT");
1648
1649 if (chunkpos < 8U) /* Return the header */ do
1650 {
1651 png_uint_32 b;
1652 unsigned int shift;
1653
1654 if (chunkpos < 4U)
1655 b = chunklen - 12U;
1656
1657 else
1658 b = chunktype;
1659
1660 shift = 3U & chunkpos;
1661 ++chunkpos;
1662
1663 if (shift < 3U)
1664 b >>= 8U*(3U-shift);
1665
1666 *pb++ = 0xffU & b;
1667 }
1668 while (--st > 0 && chunkpos < 8);
1669
1670 else /* Return chunk bytes, including the CRC */
1671 {
1672 png_size_t avail = st;
1673
1674 if (avail > chunklen - chunkpos)
1675 avail = (png_size_t)/*SAFE*/(chunklen - chunkpos);
1676
1677 store_read_imp(ps, pb, avail);
1678 pb += avail;
1679 st -= avail;
1680 chunkpos += (png_uint_32)/*SAFE*/avail;
1681
1682 /* Check for end of chunk and end-of-file; don't try to read a new
1683 * chunk header at this point unless instructed to do so by 'min'.
1684 */
1685 if (chunkpos >= chunklen && max-st >= min &&
1686 store_read_buffer_avail(ps) == 0)
1687 break;
1688 }
1689 } /* !IDAT */
1690 }
1691 while (st > 0);
1692
1693 ps->chunklen = chunklen;
1694 ps->chunktype = chunktype;
1695 ps->chunkpos = chunkpos;
1696
1697 return st; /* space left */
1698}
1699
1700static void PNGCBAPI
1701store_read(png_structp ppIn, png_bytep pb, png_size_t st)
1702{
1703 png_const_structp pp = ppIn;
1704 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1705
1706 if (ps == NULL || ps->pread != pp)
1707 png_error(pp, "bad store read call");
1708
1709 store_read_chunk(ps, pb, st, st);
1710}
1711
1712static void
1713store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
1714{
1715 if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
1716 png_error(pp, "store state damaged (progressive)");
1717
1718 /* This is another Horowitz and Hill random noise generator. In this case
1719 * the aim is to stress the progressive reader with truly horrible variable
1720 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
1721 * is generated. We could probably just count from 1 to 32767 and get as
1722 * good a result.
1723 */
1724 while (store_read_buffer_avail(ps) > 0)
1725 {
1726 static png_uint_32 noise = 2;
1727 png_size_t cb;
1728 png_byte buffer[512];
1729
1730 /* Generate 15 more bits of stuff: */
1731 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
1732 cb = noise & 0x1ff;
1733 cb -= store_read_chunk(ps, buffer, cb, 1);
1734 png_process_data(pp, pi, buffer, cb);
1735 }
1736}
1737#endif /* PNG_READ_SUPPORTED */
1738
1739/* The caller must fill this in: */
1740static store_palette_entry *
1741store_write_palette(png_store *ps, int npalette)
1742{
1743 if (ps->pwrite == NULL)
1744 store_log(ps, NULL, "attempt to write palette without write stream", 1);
1745
1746 if (ps->palette != NULL)
1747 png_error(ps->pwrite, "multiple store_write_palette calls");
1748
1749 /* This function can only return NULL if called with '0'! */
1750 if (npalette > 0)
1751 {
1752 ps->palette = voidcast(store_palette_entry*, malloc(npalette *
1753 sizeof *ps->palette));
1754
1755 if (ps->palette == NULL)
1756 png_error(ps->pwrite, "store new palette: OOM");
1757
1758 ps->npalette = npalette;
1759 }
1760
1761 return ps->palette;
1762}
1763
1764#ifdef PNG_READ_SUPPORTED
1765static store_palette_entry *
1766store_current_palette(png_store *ps, int *npalette)
1767{
1768 /* This is an internal error (the call has been made outside a read
1769 * operation.)
1770 */
1771 if (ps->current == NULL)
1772 {
1773 store_log(ps, ps->pread, "no current stream for palette", 1);
1774 return NULL;
1775 }
1776
1777 /* The result may be null if there is no palette. */
1778 *npalette = ps->current->npalette;
1779 return ps->current->palette;
1780}
1781#endif /* PNG_READ_SUPPORTED */
1782
1783/***************************** MEMORY MANAGEMENT*** ***************************/
1784#ifdef PNG_USER_MEM_SUPPORTED
1785/* A store_memory is simply the header for an allocated block of memory. The
1786 * pointer returned to libpng is just after the end of the header block, the
1787 * allocated memory is followed by a second copy of the 'mark'.
1788 */
1789typedef struct store_memory
1790{
1791 store_pool *pool; /* Originating pool */
1792 struct store_memory *next; /* Singly linked list */
1793 png_alloc_size_t size; /* Size of memory allocated */
1794 png_byte mark[4]; /* ID marker */
1795} store_memory;
1796
1797/* Handle a fatal error in memory allocation. This calls png_error if the
1798 * libpng struct is non-NULL, else it outputs a message and returns. This means
1799 * that a memory problem while libpng is running will abort (png_error) the
1800 * handling of particular file while one in cleanup (after the destroy of the
1801 * struct has returned) will simply keep going and free (or attempt to free)
1802 * all the memory.
1803 */
1804static void
1805store_pool_error(png_store *ps, png_const_structp pp, const char *msg)
1806{
1807 if (pp != NULL)
1808 png_error(pp, msg);
1809
1810 /* Else we have to do it ourselves. png_error eventually calls store_log,
1811 * above. store_log accepts a NULL png_structp - it just changes what gets
1812 * output by store_message.
1813 */
1814 store_log(ps, pp, msg, 1 /* error */);
1815}
1816
1817static void
1818store_memory_free(png_const_structp pp, store_pool *pool, store_memory *memory)
1819{
1820 /* Note that pp may be NULL (see store_pool_delete below), the caller has
1821 * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
1822 * pointer (for sure), but the contents may have been trashed.
1823 */
1824 if (memory->pool != pool)
1825 store_pool_error(pool->store, pp, "memory corrupted (pool)");
1826
1827 else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
1828 store_pool_error(pool->store, pp, "memory corrupted (start)");
1829
1830 /* It should be safe to read the size field now. */
1831 else
1832 {
1833 png_alloc_size_t cb = memory->size;
1834
1835 if (cb > pool->max)
1836 store_pool_error(pool->store, pp, "memory corrupted (size)");
1837
1838 else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
1839 != 0)
1840 store_pool_error(pool->store, pp, "memory corrupted (end)");
1841
1842 /* Finally give the library a chance to find problems too: */
1843 else
1844 {
1845 pool->current -= cb;
1846 free(memory);
1847 }
1848 }
1849}
1850
1851static void
1852store_pool_delete(png_store *ps, store_pool *pool)
1853{
1854 if (pool->list != NULL)
1855 {
1856 fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
1857 pool == &ps->read_memory_pool ? "read" : "write",
1858 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1859 ps->current->name : "unknown file") : ps->wname);
1860 ++ps->nerrors;
1861
1862 do
1863 {
1864 store_memory *next = pool->list;
1865 pool->list = next->next;
1866 next->next = NULL;
1867
1868 fprintf(stderr, "\t%lu bytes @ %p\n",
1869 (unsigned long)next->size, (const void*)(next+1));
1870 /* The NULL means this will always return, even if the memory is
1871 * corrupted.
1872 */
1873 store_memory_free(NULL, pool, next);
1874 }
1875 while (pool->list != NULL);
1876 }
1877
1878 /* And reset the other fields too for the next time. */
1879 if (pool->max > pool->max_max) pool->max_max = pool->max;
1880 pool->max = 0;
1881 if (pool->current != 0) /* unexpected internal error */
1882 fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
1883 ps->test, pool == &ps->read_memory_pool ? "read" : "write",
1884 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1885 ps->current->name : "unknown file") : ps->wname);
1886 pool->current = 0;
1887
1888 if (pool->limit > pool->max_limit)
1889 pool->max_limit = pool->limit;
1890
1891 pool->limit = 0;
1892
1893 if (pool->total > pool->max_total)
1894 pool->max_total = pool->total;
1895
1896 pool->total = 0;
1897
1898 /* Get a new mark too. */
1899 store_pool_mark(pool->mark);
1900}
1901
1902/* The memory callbacks: */
1903static png_voidp PNGCBAPI
1904store_malloc(png_structp ppIn, png_alloc_size_t cb)
1905{
1906 png_const_structp pp = ppIn;
1907 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1908 store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
1909 (sizeof pool->mark)));
1910
1911 if (new != NULL)
1912 {
1913 if (cb > pool->max)
1914 pool->max = cb;
1915
1916 pool->current += cb;
1917
1918 if (pool->current > pool->limit)
1919 pool->limit = pool->current;
1920
1921 pool->total += cb;
1922
1923 new->size = cb;
1924 memcpy(new->mark, pool->mark, sizeof new->mark);
1925 memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
1926 new->pool = pool;
1927 new->next = pool->list;
1928 pool->list = new;
1929 ++new;
1930 }
1931
1932 else
1933 {
1934 /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
1935 * other than to retrieve the allocation pointer! libpng calls the
1936 * store_malloc callback in two basic cases:
1937 *
1938 * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
1939 * returned.
1940 * 2) From png_struct or png_info structure creation; png_malloc is
1941 * to return so cleanup can be performed.
1942 *
1943 * To handle this store_malloc can log a message, but can't do anything
1944 * else.
1945 */
1946 store_log(pool->store, pp, "out of memory", 1 /* is_error */);
1947 }
1948
1949 return new;
1950}
1951
1952static void PNGCBAPI
1953store_free(png_structp ppIn, png_voidp memory)
1954{
1955 png_const_structp pp = ppIn;
1956 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1957 store_memory *this = voidcast(store_memory*, memory), **test;
1958
1959 /* Because libpng calls store_free with a dummy png_struct when deleting
1960 * png_struct or png_info via png_destroy_struct_2 it is necessary to check
1961 * the passed in png_structp to ensure it is valid, and not pass it to
1962 * png_error if it is not.
1963 */
1964 if (pp != pool->store->pread && pp != pool->store->pwrite)
1965 pp = NULL;
1966
1967 /* First check that this 'memory' really is valid memory - it must be in the
1968 * pool list. If it is, use the shared memory_free function to free it.
1969 */
1970 --this;
1971 for (test = &pool->list; *test != this; test = &(*test)->next)
1972 {
1973 if (*test == NULL)
1974 {
1975 store_pool_error(pool->store, pp, "bad pointer to free");
1976 return;
1977 }
1978 }
1979
1980 /* Unlink this entry, *test == this. */
1981 *test = this->next;
1982 this->next = NULL;
1983 store_memory_free(pp, pool, this);
1984}
1985#endif /* PNG_USER_MEM_SUPPORTED */
1986
1987/* Setup functions. */
1988/* Cleanup when aborting a write or after storing the new file. */
1989static void
1990store_write_reset(png_store *ps)
1991{
1992 if (ps->pwrite != NULL)
1993 {
1994 anon_context(ps);
1995
1996 Try
1997 png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
1998
1999 Catch_anonymous
2000 {
2001 /* memory corruption: continue. */
2002 }
2003
2004 ps->pwrite = NULL;
2005 ps->piwrite = NULL;
2006 }
2007
2008 /* And make sure that all the memory has been freed - this will output
2009 * spurious errors in the case of memory corruption above, but this is safe.
2010 */
2011# ifdef PNG_USER_MEM_SUPPORTED
2012 store_pool_delete(ps, &ps->write_memory_pool);
2013# endif
2014
2015 store_freenew(ps);
2016}
2017
2018/* The following is the main write function, it returns a png_struct and,
2019 * optionally, a png_info suitable for writiing a new PNG file. Use
2020 * store_storefile above to record this file after it has been written. The
2021 * returned libpng structures as destroyed by store_write_reset above.
2022 */
2023static png_structp
2024set_store_for_write(png_store *ps, png_infopp ppi, const char *name)
2025{
2026 anon_context(ps);
2027
2028 Try
2029 {
2030 if (ps->pwrite != NULL)
2031 png_error(ps->pwrite, "write store already in use");
2032
2033 store_write_reset(ps);
2034 safecat(ps->wname, sizeof ps->wname, 0, name);
2035
2036 /* Don't do the slow memory checks if doing a speed test, also if user
2037 * memory is not supported we can't do it anyway.
2038 */
2039# ifdef PNG_USER_MEM_SUPPORTED
2040 if (!ps->speed)
2041 ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
2042 ps, store_error, store_warning, &ps->write_memory_pool,
2043 store_malloc, store_free);
2044
2045 else
2046# endif
2047 ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
2048 ps, store_error, store_warning);
2049
2050 png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
2051
2052# ifdef PNG_SET_OPTION_SUPPORTED
2053 {
2054 int opt;
2055 for (opt=0; opt<ps->noptions; ++opt)
2056 if (png_set_option(ps->pwrite, ps->options[opt].option,
2057 ps->options[opt].setting) == PNG_OPTION_INVALID)
2058 png_error(ps->pwrite, "png option invalid");
2059 }
2060# endif
2061
2062 if (ppi != NULL)
2063 *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
2064 }
2065
2066 Catch_anonymous
2067 return NULL;
2068
2069 return ps->pwrite;
2070}
2071
2072/* Cleanup when finished reading (either due to error or in the success case).
2073 * This routine exists even when there is no read support to make the code
2074 * tidier (avoid a mass of ifdefs) and so easier to maintain.
2075 */
2076static void
2077store_read_reset(png_store *ps)
2078{
2079# ifdef PNG_READ_SUPPORTED
2080 if (ps->pread != NULL)
2081 {
2082 anon_context(ps);
2083
2084 Try
2085 png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
2086
2087 Catch_anonymous
2088 {
2089 /* error already output: continue */
2090 }
2091
2092 ps->pread = NULL;
2093 ps->piread = NULL;
2094 }
2095# endif
2096
2097# ifdef PNG_USER_MEM_SUPPORTED
2098 /* Always do this to be safe. */
2099 store_pool_delete(ps, &ps->read_memory_pool);
2100# endif
2101
2102 ps->current = NULL;
2103 ps->next = NULL;
2104 ps->readpos = 0;
2105 ps->validated = 0;
2106
2107 ps->chunkpos = 8;
2108 ps->chunktype = 0;
2109 ps->chunklen = 16;
2110 ps->IDAT_size = 0;
2111}
2112
2113#ifdef PNG_READ_SUPPORTED
2114static void
2115store_read_set(png_store *ps, png_uint_32 id)
2116{
2117 png_store_file *pf = ps->saved;
2118
2119 while (pf != NULL)
2120 {
2121 if (pf->id == id)
2122 {
2123 ps->current = pf;
2124 ps->next = NULL;
2125 ps->IDAT_size = pf->IDAT_size;
2126 ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
2127 ps->IDAT_len = 0;
2128 ps->IDAT_pos = 0;
2129 ps->IDAT_crc = 0UL;
2130 store_read_buffer_next(ps);
2131 return;
2132 }
2133
2134 pf = pf->next;
2135 }
2136
2137 {
2138 size_t pos;
2139 char msg[FILE_NAME_SIZE+64];
2140
2141 pos = standard_name_from_id(msg, sizeof msg, 0, id);
2142 pos = safecat(msg, sizeof msg, pos, ": file not found");
2143 png_error(ps->pread, msg);
2144 }
2145}
2146
2147/* The main interface for reading a saved file - pass the id number of the file
2148 * to retrieve. Ids must be unique or the earlier file will be hidden. The API
2149 * returns a png_struct and, optionally, a png_info. Both of these will be
2150 * destroyed by store_read_reset above.
2151 */
2152static png_structp
2153set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
2154 const char *name)
2155{
2156 /* Set the name for png_error */
2157 safecat(ps->test, sizeof ps->test, 0, name);
2158
2159 if (ps->pread != NULL)
2160 png_error(ps->pread, "read store already in use");
2161
2162 store_read_reset(ps);
2163
2164 /* Both the create APIs can return NULL if used in their default mode
2165 * (because there is no other way of handling an error because the jmp_buf
2166 * by default is stored in png_struct and that has not been allocated!)
2167 * However, given that store_error works correctly in these circumstances
2168 * we don't ever expect NULL in this program.
2169 */
2170# ifdef PNG_USER_MEM_SUPPORTED
2171 if (!ps->speed)
2172 ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
2173 store_error, store_warning, &ps->read_memory_pool, store_malloc,
2174 store_free);
2175
2176 else
2177# endif
2178 ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error,
2179 store_warning);
2180
2181 if (ps->pread == NULL)
2182 {
2183 struct exception_context *the_exception_context = &ps->exception_context;
2184
2185 store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
2186 1 /*error*/);
2187
2188 Throw ps;
2189 }
2190
2191# ifdef PNG_SET_OPTION_SUPPORTED
2192 {
2193 int opt;
2194 for (opt=0; opt<ps->noptions; ++opt)
2195 if (png_set_option(ps->pread, ps->options[opt].option,
2196 ps->options[opt].setting) == PNG_OPTION_INVALID)
2197 png_error(ps->pread, "png option invalid");
2198 }
2199# endif
2200
2201 store_read_set(ps, id);
2202
2203 if (ppi != NULL)
2204 *ppi = ps->piread = png_create_info_struct(ps->pread);
2205
2206 return ps->pread;
2207}
2208#endif /* PNG_READ_SUPPORTED */
2209
2210/* The overall cleanup of a store simply calls the above then removes all the
2211 * saved files. This does not delete the store itself.
2212 */
2213static void
2214store_delete(png_store *ps)
2215{
2216 store_write_reset(ps);
2217 store_read_reset(ps);
2218 store_freefile(&ps->saved);
2219 store_image_free(ps, NULL);
2220}
2221
2222/*********************** PNG FILE MODIFICATION ON READ ************************/
2223/* Files may be modified on read. The following structure contains a complete
2224 * png_store together with extra members to handle modification and a special
2225 * read callback for libpng. To use this the 'modifications' field must be set
2226 * to a list of png_modification structures that actually perform the
2227 * modification, otherwise a png_modifier is functionally equivalent to a
2228 * png_store. There is a special read function, set_modifier_for_read, which
2229 * replaces set_store_for_read.
2230 */
2231typedef enum modifier_state
2232{
2233 modifier_start, /* Initial value */
2234 modifier_signature, /* Have a signature */
2235 modifier_IHDR /* Have an IHDR */
2236} modifier_state;
2237
2238typedef struct CIE_color
2239{
2240 /* A single CIE tristimulus value, representing the unique response of a
2241 * standard observer to a variety of light spectra. The observer recognizes
2242 * all spectra that produce this response as the same color, therefore this
2243 * is effectively a description of a color.
2244 */
2245 double X, Y, Z;
2246} CIE_color;
2247
2248typedef struct color_encoding
2249{
2250 /* A description of an (R,G,B) encoding of color (as defined above); this
2251 * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
2252 * (0,0,1) plus an encoding value that is used to encode the linear
2253 * components R, G and B to give the actual values R^gamma, G^gamma and
2254 * B^gamma that are stored.
2255 */
2256 double gamma; /* Encoding (file) gamma of space */
2257 CIE_color red, green, blue; /* End points */
2258} color_encoding;
2259
2260#ifdef PNG_READ_SUPPORTED
2261#if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED
2262static double
2263chromaticity_x(CIE_color c)
2264{
2265 return c.X / (c.X + c.Y + c.Z);
2266}
2267
2268static double
2269chromaticity_y(CIE_color c)
2270{
2271 return c.Y / (c.X + c.Y + c.Z);
2272}
2273
2274static CIE_color
2275white_point(const color_encoding *encoding)
2276{
2277 CIE_color white;
2278
2279 white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
2280 white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
2281 white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
2282
2283 return white;
2284}
2285#endif /* READ_TRANSFORMS && READ_cHRM */
2286
2287#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2288static void
2289normalize_color_encoding(color_encoding *encoding)
2290{
2291 const double whiteY = encoding->red.Y + encoding->green.Y +
2292 encoding->blue.Y;
2293
2294 if (whiteY != 1)
2295 {
2296 encoding->red.X /= whiteY;
2297 encoding->red.Y /= whiteY;
2298 encoding->red.Z /= whiteY;
2299 encoding->green.X /= whiteY;
2300 encoding->green.Y /= whiteY;
2301 encoding->green.Z /= whiteY;
2302 encoding->blue.X /= whiteY;
2303 encoding->blue.Y /= whiteY;
2304 encoding->blue.Z /= whiteY;
2305 }
2306}
2307#endif
2308
2309#ifdef PNG_READ_TRANSFORMS_SUPPORTED
2310static size_t
2311safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
2312 const color_encoding *e, double encoding_gamma)
2313{
2314 if (e != 0)
2315 {
2316 if (encoding_gamma != 0)
2317 pos = safecat(buffer, bufsize, pos, "(");
2318 pos = safecat(buffer, bufsize, pos, "R(");
2319 pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
2320 pos = safecat(buffer, bufsize, pos, ",");
2321 pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
2322 pos = safecat(buffer, bufsize, pos, ",");
2323 pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
2324 pos = safecat(buffer, bufsize, pos, "),G(");
2325 pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
2326 pos = safecat(buffer, bufsize, pos, ",");
2327 pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
2328 pos = safecat(buffer, bufsize, pos, ",");
2329 pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
2330 pos = safecat(buffer, bufsize, pos, "),B(");
2331 pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
2332 pos = safecat(buffer, bufsize, pos, ",");
2333 pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
2334 pos = safecat(buffer, bufsize, pos, ",");
2335 pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
2336 pos = safecat(buffer, bufsize, pos, ")");
2337 if (encoding_gamma != 0)
2338 pos = safecat(buffer, bufsize, pos, ")");
2339 }
2340
2341 if (encoding_gamma != 0)
2342 {
2343 pos = safecat(buffer, bufsize, pos, "^");
2344 pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
2345 }
2346
2347 return pos;
2348}
2349#endif /* READ_TRANSFORMS */
2350#endif /* PNG_READ_SUPPORTED */
2351
2352typedef struct png_modifier
2353{
2354 png_store this; /* I am a png_store */
2355 struct png_modification *modifications; /* Changes to make */
2356
2357 modifier_state state; /* My state */
2358
2359 /* Information from IHDR: */
2360 png_byte bit_depth; /* From IHDR */
2361 png_byte colour_type; /* From IHDR */
2362
2363 /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
2364 * other chunks to be inserted.
2365 */
2366 png_uint_32 pending_len;
2367 png_uint_32 pending_chunk;
2368
2369 /* Test values */
2370 double *gammas;
2371 unsigned int ngammas;
2372 unsigned int ngamma_tests; /* Number of gamma tests to run*/
2373 double current_gamma; /* 0 if not set */
2374 const color_encoding *encodings;
2375 unsigned int nencodings;
2376 const color_encoding *current_encoding; /* If an encoding has been set */
2377 unsigned int encoding_counter; /* For iteration */
2378 int encoding_ignored; /* Something overwrote it */
2379
2380 /* Control variables used to iterate through possible encodings, the
2381 * following must be set to 0 and tested by the function that uses the
2382 * png_modifier because the modifier only sets it to 1 (true.)
2383 */
2384 unsigned int repeat :1; /* Repeat this transform test. */
2385 unsigned int test_uses_encoding :1;
2386
2387 /* Lowest sbit to test (pre-1.7 libpng fails for sbit < 8) */
2388 png_byte sbitlow;
2389
2390 /* Error control - these are the limits on errors accepted by the gamma tests
2391 * below.
2392 */
2393 double maxout8; /* Maximum output value error */
2394 double maxabs8; /* Absolute sample error 0..1 */
2395 double maxcalc8; /* Absolute sample error 0..1 */
2396 double maxpc8; /* Percentage sample error 0..100% */
2397 double maxout16; /* Maximum output value error */
2398 double maxabs16; /* Absolute sample error 0..1 */
2399 double maxcalc16;/* Absolute sample error 0..1 */
2400 double maxcalcG; /* Absolute sample error 0..1 */
2401 double maxpc16; /* Percentage sample error 0..100% */
2402
2403 /* This is set by transforms that need to allow a higher limit, it is an
2404 * internal check on pngvalid to ensure that the calculated error limits are
2405 * not ridiculous; without this it is too easy to make a mistake in pngvalid
2406 * that allows any value through.
2407 *
2408 * NOTE: this is not checked in release builds.
2409 */
2410 double limit; /* limit on error values, normally 4E-3 */
2411
2412 /* Log limits - values above this are logged, but not necessarily
2413 * warned.
2414 */
2415 double log8; /* Absolute error in 8 bits to log */
2416 double log16; /* Absolute error in 16 bits to log */
2417
2418 /* Logged 8 and 16 bit errors ('output' values): */
2419 double error_gray_2;
2420 double error_gray_4;
2421 double error_gray_8;
2422 double error_gray_16;
2423 double error_color_8;
2424 double error_color_16;
2425 double error_indexed;
2426
2427 /* Flags: */
2428 /* Whether to call png_read_update_info, not png_read_start_image, and how
2429 * many times to call it.
2430 */
2431 int use_update_info;
2432
2433 /* Whether or not to interlace. */
2434 int interlace_type :9; /* int, but must store '1' */
2435
2436 /* Run the standard tests? */
2437 unsigned int test_standard :1;
2438
2439 /* Run the odd-sized image and interlace read/write tests? */
2440 unsigned int test_size :1;
2441
2442 /* Run tests on reading with a combination of transforms, */
2443 unsigned int test_transform :1;
2444 unsigned int test_tRNS :1; /* Includes tRNS images */
2445
2446 /* When to use the use_input_precision option, this controls the gamma
2447 * validation code checks. If set any value that is within the transformed
2448 * range input-.5 to input+.5 will be accepted, otherwise the value must be
2449 * within the normal limits. It should not be necessary to set this; the
2450 * result should always be exact within the permitted error limits.
2451 */
2452 unsigned int use_input_precision :1;
2453 unsigned int use_input_precision_sbit :1;
2454 unsigned int use_input_precision_16to8 :1;
2455
2456 /* If set assume that the calculation bit depth is set by the input
2457 * precision, not the output precision.
2458 */
2459 unsigned int calculations_use_input_precision :1;
2460
2461 /* If set assume that the calculations are done in 16 bits even if the sample
2462 * depth is 8 bits.
2463 */
2464 unsigned int assume_16_bit_calculations :1;
2465
2466 /* Which gamma tests to run: */
2467 unsigned int test_gamma_threshold :1;
2468 unsigned int test_gamma_transform :1; /* main tests */
2469 unsigned int test_gamma_sbit :1;
2470 unsigned int test_gamma_scale16 :1;
2471 unsigned int test_gamma_background :1;
2472 unsigned int test_gamma_alpha_mode :1;
2473 unsigned int test_gamma_expand16 :1;
2474 unsigned int test_exhaustive :1;
2475
2476 /* Whether or not to run the low-bit-depth grayscale tests. This fails on
2477 * gamma images in some cases because of gross inaccuracies in the grayscale
2478 * gamma handling for low bit depth.
2479 */
2480 unsigned int test_lbg :1;
2481 unsigned int test_lbg_gamma_threshold :1;
2482 unsigned int test_lbg_gamma_transform :1;
2483 unsigned int test_lbg_gamma_sbit :1;
2484 unsigned int test_lbg_gamma_composition :1;
2485
2486 unsigned int log :1; /* Log max error */
2487
2488 /* Buffer information, the buffer size limits the size of the chunks that can
2489 * be modified - they must fit (including header and CRC) into the buffer!
2490 */
2491 size_t flush; /* Count of bytes to flush */
2492 size_t buffer_count; /* Bytes in buffer */
2493 size_t buffer_position; /* Position in buffer */
2494 png_byte buffer[1024];
2495} png_modifier;
2496
2497/* This returns true if the test should be stopped now because it has already
2498 * failed and it is running silently.
2499 */
2500static int fail(png_modifier *pm)
2501{
2502 return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
2503 (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
2504}
2505
2506static void
2507modifier_init(png_modifier *pm)
2508{
2509 memset(pm, 0, sizeof *pm);
2510 store_init(&pm->this);
2511 pm->modifications = NULL;
2512 pm->state = modifier_start;
2513 pm->sbitlow = 1U;
2514 pm->ngammas = 0;
2515 pm->ngamma_tests = 0;
2516 pm->gammas = 0;
2517 pm->current_gamma = 0;
2518 pm->encodings = 0;
2519 pm->nencodings = 0;
2520 pm->current_encoding = 0;
2521 pm->encoding_counter = 0;
2522 pm->encoding_ignored = 0;
2523 pm->repeat = 0;
2524 pm->test_uses_encoding = 0;
2525 pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
2526 pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
2527 pm->maxcalcG = 0;
2528 pm->limit = 4E-3;
2529 pm->log8 = pm->log16 = 0; /* Means 'off' */
2530 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
2531 pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
2532 pm->error_indexed = 0;
2533 pm->use_update_info = 0;
2534 pm->interlace_type = PNG_INTERLACE_NONE;
2535 pm->test_standard = 0;
2536 pm->test_size = 0;
2537 pm->test_transform = 0;
2538# ifdef PNG_WRITE_tRNS_SUPPORTED
2539 pm->test_tRNS = 1;
2540# else
2541 pm->test_tRNS = 0;
2542# endif
2543 pm->use_input_precision = 0;
2544 pm->use_input_precision_sbit = 0;
2545 pm->use_input_precision_16to8 = 0;
2546 pm->calculations_use_input_precision = 0;
2547 pm->assume_16_bit_calculations = 0;
2548 pm->test_gamma_threshold = 0;
2549 pm->test_gamma_transform = 0;
2550 pm->test_gamma_sbit = 0;
2551 pm->test_gamma_scale16 = 0;
2552 pm->test_gamma_background = 0;
2553 pm->test_gamma_alpha_mode = 0;
2554 pm->test_gamma_expand16 = 0;
2555 pm->test_lbg = 1;
2556 pm->test_lbg_gamma_threshold = 1;
2557 pm->test_lbg_gamma_transform = 1;
2558 pm->test_lbg_gamma_sbit = 1;
2559 pm->test_lbg_gamma_composition = 1;
2560 pm->test_exhaustive = 0;
2561 pm->log = 0;
2562
2563 /* Rely on the memset for all the other fields - there are no pointers */
2564}
2565
2566#ifdef PNG_READ_TRANSFORMS_SUPPORTED
2567
2568/* This controls use of checks that explicitly know how libpng digitizes the
2569 * samples in calculations; setting this circumvents simple error limit checking
2570 * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5
2571 * algorithm.
2572 */
2573#define DIGITIZE PNG_LIBPNG_VER < 10700
2574
2575/* If pm->calculations_use_input_precision is set then operations will happen
2576 * with the precision of the input, not the precision of the output depth.
2577 *
2578 * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
2579 * bit precision. This only affects those of the following limits that pertain
2580 * to a calculation - not a digitization operation - unless the following API is
2581 * called directly.
2582 */
2583#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2584#if DIGITIZE
2585static double digitize(double value, int depth, int do_round)
2586{
2587 /* 'value' is in the range 0 to 1, the result is the same value rounded to a
2588 * multiple of the digitization factor - 8 or 16 bits depending on both the
2589 * sample depth and the 'assume' setting. Digitization is normally by
2590 * rounding and 'do_round' should be 1, if it is 0 the digitized value will
2591 * be truncated.
2592 */
2593 const unsigned int digitization_factor = (1U << depth) -1;
2594
2595 /* Limiting the range is done as a convenience to the caller - it's easier to
2596 * do it once here than every time at the call site.
2597 */
2598 if (value <= 0)
2599 value = 0;
2600
2601 else if (value >= 1)
2602 value = 1;
2603
2604 value *= digitization_factor;
2605 if (do_round) value += .5;
2606 return floor(value)/digitization_factor;
2607}
2608#endif
2609#endif /* RGB_TO_GRAY */
2610
2611#ifdef PNG_READ_GAMMA_SUPPORTED
2612static double abserr(const png_modifier *pm, int in_depth, int out_depth)
2613{
2614 /* Absolute error permitted in linear values - affected by the bit depth of
2615 * the calculations.
2616 */
2617 if (pm->assume_16_bit_calculations ||
2618 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2619 return pm->maxabs16;
2620 else
2621 return pm->maxabs8;
2622}
2623
2624static double calcerr(const png_modifier *pm, int in_depth, int out_depth)
2625{
2626 /* Error in the linear composition arithmetic - only relevant when
2627 * composition actually happens (0 < alpha < 1).
2628 */
2629 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2630 return pm->maxcalc16;
2631 else if (pm->assume_16_bit_calculations)
2632 return pm->maxcalcG;
2633 else
2634 return pm->maxcalc8;
2635}
2636
2637static double pcerr(const png_modifier *pm, int in_depth, int out_depth)
2638{
2639 /* Percentage error permitted in the linear values. Note that the specified
2640 * value is a percentage but this routine returns a simple number.
2641 */
2642 if (pm->assume_16_bit_calculations ||
2643 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2644 return pm->maxpc16 * .01;
2645 else
2646 return pm->maxpc8 * .01;
2647}
2648
2649/* Output error - the error in the encoded value. This is determined by the
2650 * digitization of the output so can be +/-0.5 in the actual output value. In
2651 * the expand_16 case with the current code in libpng the expand happens after
2652 * all the calculations are done in 8 bit arithmetic, so even though the output
2653 * depth is 16 the output error is determined by the 8 bit calculation.
2654 *
2655 * This limit is not determined by the bit depth of internal calculations.
2656 *
2657 * The specified parameter does *not* include the base .5 digitization error but
2658 * it is added here.
2659 */
2660static double outerr(const png_modifier *pm, int in_depth, int out_depth)
2661{
2662 /* There is a serious error in the 2 and 4 bit grayscale transform because
2663 * the gamma table value (8 bits) is simply shifted, not rounded, so the
2664 * error in 4 bit grayscale gamma is up to the value below. This is a hack
2665 * to allow pngvalid to succeed:
2666 *
2667 * TODO: fix this in libpng
2668 */
2669 if (out_depth == 2)
2670 return .73182-.5;
2671
2672 if (out_depth == 4)
2673 return .90644-.5;
2674
2675 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2676 return pm->maxout16;
2677
2678 /* This is the case where the value was calculated at 8-bit precision then
2679 * scaled to 16 bits.
2680 */
2681 else if (out_depth == 16)
2682 return pm->maxout8 * 257;
2683
2684 else
2685 return pm->maxout8;
2686}
2687
2688/* This does the same thing as the above however it returns the value to log,
2689 * rather than raising a warning. This is useful for debugging to track down
2690 * exactly what set of parameters cause high error values.
2691 */
2692static double outlog(const png_modifier *pm, int in_depth, int out_depth)
2693{
2694 /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
2695 * and so must be adjusted for low bit depth grayscale:
2696 */
2697 if (out_depth <= 8)
2698 {
2699 if (pm->log8 == 0) /* switched off */
2700 return 256;
2701
2702 if (out_depth < 8)
2703 return pm->log8 / 255 * ((1<<out_depth)-1);
2704
2705 return pm->log8;
2706 }
2707
2708 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2709 {
2710 if (pm->log16 == 0)
2711 return 65536;
2712
2713 return pm->log16;
2714 }
2715
2716 /* This is the case where the value was calculated at 8-bit precision then
2717 * scaled to 16 bits.
2718 */
2719 if (pm->log8 == 0)
2720 return 65536;
2721
2722 return pm->log8 * 257;
2723}
2724
2725/* This complements the above by providing the appropriate quantization for the
2726 * final value. Normally this would just be quantization to an integral value,
2727 * but in the 8 bit calculation case it's actually quantization to a multiple of
2728 * 257!
2729 */
2730static int output_quantization_factor(const png_modifier *pm, int in_depth,
2731 int out_depth)
2732{
2733 if (out_depth == 16 && in_depth != 16 &&
2734 pm->calculations_use_input_precision)
2735 return 257;
2736 else
2737 return 1;
2738}
2739#endif /* PNG_READ_GAMMA_SUPPORTED */
2740
2741/* One modification structure must be provided for each chunk to be modified (in
2742 * fact more than one can be provided if multiple separate changes are desired
2743 * for a single chunk.) Modifications include adding a new chunk when a
2744 * suitable chunk does not exist.
2745 *
2746 * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
2747 * or 'added' as appropriate if the modify_fn returns 1 (true). If the
2748 * modify_fn is NULL the chunk is simply removed.
2749 */
2750typedef struct png_modification
2751{
2752 struct png_modification *next;
2753 png_uint_32 chunk;
2754
2755 /* If the following is NULL all matching chunks will be removed: */
2756 int (*modify_fn)(struct png_modifier *pm,
2757 struct png_modification *me, int add);
2758
2759 /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
2760 * found and modified (and there is a modify_fn) the modify_fn will be called
2761 * to add the chunk before the relevant chunk.
2762 */
2763 png_uint_32 add;
2764 unsigned int modified :1; /* Chunk was modified */
2765 unsigned int added :1; /* Chunk was added */
2766 unsigned int removed :1; /* Chunk was removed */
2767} png_modification;
2768
2769static void
2770modification_reset(png_modification *pmm)
2771{
2772 if (pmm != NULL)
2773 {
2774 pmm->modified = 0;
2775 pmm->added = 0;
2776 pmm->removed = 0;
2777 modification_reset(pmm->next);
2778 }
2779}
2780
2781static void
2782modification_init(png_modification *pmm)
2783{
2784 memset(pmm, 0, sizeof *pmm);
2785 pmm->next = NULL;
2786 pmm->chunk = 0;
2787 pmm->modify_fn = NULL;
2788 pmm->add = 0;
2789 modification_reset(pmm);
2790}
2791
2792#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2793static void
2794modifier_current_encoding(const png_modifier *pm, color_encoding *ce)
2795{
2796 if (pm->current_encoding != 0)
2797 *ce = *pm->current_encoding;
2798
2799 else
2800 memset(ce, 0, sizeof *ce);
2801
2802 ce->gamma = pm->current_gamma;
2803}
2804#endif
2805
2806#ifdef PNG_READ_TRANSFORMS_SUPPORTED
2807static size_t
2808safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
2809 const png_modifier *pm)
2810{
2811 pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
2812 pm->current_gamma);
2813
2814 if (pm->encoding_ignored)
2815 pos = safecat(buffer, bufsize, pos, "[overridden]");
2816
2817 return pos;
2818}
2819#endif
2820
2821/* Iterate through the usefully testable color encodings. An encoding is one
2822 * of:
2823 *
2824 * 1) Nothing (no color space, no gamma).
2825 * 2) Just a gamma value from the gamma array (including 1.0)
2826 * 3) A color space from the encodings array with the corresponding gamma.
2827 * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
2828 *
2829 * The iterator selects these in turn, the randomizer selects one at random,
2830 * which is used depends on the setting of the 'test_exhaustive' flag. Notice
2831 * that this function changes the colour space encoding so it must only be
2832 * called on completion of the previous test. This is what 'modifier_reset'
2833 * does, below.
2834 *
2835 * After the function has been called the 'repeat' flag will still be set; the
2836 * caller of modifier_reset must reset it at the start of each run of the test!
2837 */
2838static unsigned int
2839modifier_total_encodings(const png_modifier *pm)
2840{
2841 return 1 + /* (1) nothing */
2842 pm->ngammas + /* (2) gamma values to test */
2843 pm->nencodings + /* (3) total number of encodings */
2844 /* The following test only works after the first time through the
2845 * png_modifier code because 'bit_depth' is set when the IHDR is read.
2846 * modifier_reset, below, preserves the setting until after it has called
2847 * the iterate function (also below.)
2848 *
2849 * For this reason do not rely on this function outside a call to
2850 * modifier_reset.
2851 */
2852 ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
2853 pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
2854}
2855
2856static void
2857modifier_encoding_iterate(png_modifier *pm)
2858{
2859 if (!pm->repeat && /* Else something needs the current encoding again. */
2860 pm->test_uses_encoding) /* Some transform is encoding dependent */
2861 {
2862 if (pm->test_exhaustive)
2863 {
2864 if (++pm->encoding_counter >= modifier_total_encodings(pm))
2865 pm->encoding_counter = 0; /* This will stop the repeat */
2866 }
2867
2868 else
2869 {
2870 /* Not exhaustive - choose an encoding at random; generate a number in
2871 * the range 1..(max-1), so the result is always non-zero:
2872 */
2873 if (pm->encoding_counter == 0)
2874 pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
2875 else
2876 pm->encoding_counter = 0;
2877 }
2878
2879 if (pm->encoding_counter > 0)
2880 pm->repeat = 1;
2881 }
2882
2883 else if (!pm->repeat)
2884 pm->encoding_counter = 0;
2885}
2886
2887static void
2888modifier_reset(png_modifier *pm)
2889{
2890 store_read_reset(&pm->this);
2891 pm->limit = 4E-3;
2892 pm->pending_len = pm->pending_chunk = 0;
2893 pm->flush = pm->buffer_count = pm->buffer_position = 0;
2894 pm->modifications = NULL;
2895 pm->state = modifier_start;
2896 modifier_encoding_iterate(pm);
2897 /* The following must be set in the next run. In particular
2898 * test_uses_encodings must be set in the _ini function of each transform
2899 * that looks at the encodings. (Not the 'add' function!)
2900 */
2901 pm->test_uses_encoding = 0;
2902 pm->current_gamma = 0;
2903 pm->current_encoding = 0;
2904 pm->encoding_ignored = 0;
2905 /* These only become value after IHDR is read: */
2906 pm->bit_depth = pm->colour_type = 0;
2907}
2908
2909/* The following must be called before anything else to get the encoding set up
2910 * on the modifier. In particular it must be called before the transform init
2911 * functions are called.
2912 */
2913static void
2914modifier_set_encoding(png_modifier *pm)
2915{
2916 /* Set the encoding to the one specified by the current encoding counter,
2917 * first clear out all the settings - this corresponds to an encoding_counter
2918 * of 0.
2919 */
2920 pm->current_gamma = 0;
2921 pm->current_encoding = 0;
2922 pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
2923
2924 /* Now, if required, set the gamma and encoding fields. */
2925 if (pm->encoding_counter > 0)
2926 {
2927 /* The gammas[] array is an array of screen gammas, not encoding gammas,
2928 * so we need the inverse:
2929 */
2930 if (pm->encoding_counter <= pm->ngammas)
2931 pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
2932
2933 else
2934 {
2935 unsigned int i = pm->encoding_counter - pm->ngammas;
2936
2937 if (i >= pm->nencodings)
2938 {
2939 i %= pm->nencodings;
2940 pm->current_gamma = 1; /* Linear, only in the 16 bit case */
2941 }
2942
2943 else
2944 pm->current_gamma = pm->encodings[i].gamma;
2945
2946 pm->current_encoding = pm->encodings + i;
2947 }
2948 }
2949}
2950
2951/* Enquiry functions to find out what is set. Notice that there is an implicit
2952 * assumption below that the first encoding in the list is the one for sRGB.
2953 */
2954static int
2955modifier_color_encoding_is_sRGB(const png_modifier *pm)
2956{
2957 return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
2958 pm->current_encoding->gamma == pm->current_gamma;
2959}
2960
2961static int
2962modifier_color_encoding_is_set(const png_modifier *pm)
2963{
2964 return pm->current_gamma != 0;
2965}
2966
2967/* The guts of modification are performed during a read. */
2968static void
2969modifier_crc(png_bytep buffer)
2970{
2971 /* Recalculate the chunk CRC - a complete chunk must be in
2972 * the buffer, at the start.
2973 */
2974 uInt datalen = png_get_uint_32(buffer);
2975 uLong crc = crc32(0, buffer+4, datalen+4);
2976 /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
2977 */
2978 png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
2979}
2980
2981static void
2982modifier_setbuffer(png_modifier *pm)
2983{
2984 modifier_crc(pm->buffer);
2985 pm->buffer_count = png_get_uint_32(pm->buffer)+12;
2986 pm->buffer_position = 0;
2987}
2988
2989/* Separate the callback into the actual implementation (which is passed the
2990 * png_modifier explicitly) and the callback, which gets the modifier from the
2991 * png_struct.
2992 */
2993static void
2994modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
2995{
2996 while (st > 0)
2997 {
2998 size_t cb;
2999 png_uint_32 len, chunk;
3000 png_modification *mod;
3001
3002 if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
3003 {
3004 static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
3005 case modifier_start:
3006 store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
3007 pm->buffer_count = 8;
3008 pm->buffer_position = 0;
3009
3010 if (memcmp(pm->buffer, sign, 8) != 0)
3011 png_error(pm->this.pread, "invalid PNG file signature");
3012 pm->state = modifier_signature;
3013 break;
3014
3015 case modifier_signature:
3016 store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
3017 pm->buffer_count = 13+12;
3018 pm->buffer_position = 0;
3019
3020 if (png_get_uint_32(pm->buffer) != 13 ||
3021 png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
3022 png_error(pm->this.pread, "invalid IHDR");
3023
3024 /* Check the list of modifiers for modifications to the IHDR. */
3025 mod = pm->modifications;
3026 while (mod != NULL)
3027 {
3028 if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
3029 (*mod->modify_fn)(pm, mod, 0))
3030 {
3031 mod->modified = 1;
3032 modifier_setbuffer(pm);
3033 }
3034
3035 /* Ignore removal or add if IHDR! */
3036 mod = mod->next;
3037 }
3038
3039 /* Cache information from the IHDR (the modified one.) */
3040 pm->bit_depth = pm->buffer[8+8];
3041 pm->colour_type = pm->buffer[8+8+1];
3042
3043 pm->state = modifier_IHDR;
3044 pm->flush = 0;
3045 break;
3046
3047 case modifier_IHDR:
3048 default:
3049 /* Read a new chunk and process it until we see PLTE, IDAT or
3050 * IEND. 'flush' indicates that there is still some data to
3051 * output from the preceding chunk.
3052 */
3053 if ((cb = pm->flush) > 0)
3054 {
3055 if (cb > st) cb = st;
3056 pm->flush -= cb;
3057 store_read_chunk(&pm->this, pb, cb, cb);
3058 pb += cb;
3059 st -= cb;
3060 if (st == 0) return;
3061 }
3062
3063 /* No more bytes to flush, read a header, or handle a pending
3064 * chunk.
3065 */
3066 if (pm->pending_chunk != 0)
3067 {
3068 png_save_uint_32(pm->buffer, pm->pending_len);
3069 png_save_uint_32(pm->buffer+4, pm->pending_chunk);
3070 pm->pending_len = 0;
3071 pm->pending_chunk = 0;
3072 }
3073 else
3074 store_read_chunk(&pm->this, pm->buffer, 8, 8);
3075
3076 pm->buffer_count = 8;
3077 pm->buffer_position = 0;
3078
3079 /* Check for something to modify or a terminator chunk. */
3080 len = png_get_uint_32(pm->buffer);
3081 chunk = png_get_uint_32(pm->buffer+4);
3082
3083 /* Terminators first, they may have to be delayed for added
3084 * chunks
3085 */
3086 if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
3087 chunk == CHUNK_IEND)
3088 {
3089 mod = pm->modifications;
3090
3091 while (mod != NULL)
3092 {
3093 if ((mod->add == chunk ||
3094 (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
3095 mod->modify_fn != NULL && !mod->modified && !mod->added)
3096 {
3097 /* Regardless of what the modify function does do not run
3098 * this again.
3099 */
3100 mod->added = 1;
3101
3102 if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
3103 {
3104 /* Reset the CRC on a new chunk */
3105 if (pm->buffer_count > 0)
3106 modifier_setbuffer(pm);
3107
3108 else
3109 {
3110 pm->buffer_position = 0;
3111 mod->removed = 1;
3112 }
3113
3114 /* The buffer has been filled with something (we assume)
3115 * so output this. Pend the current chunk.
3116 */
3117 pm->pending_len = len;
3118 pm->pending_chunk = chunk;
3119 break; /* out of while */
3120 }
3121 }
3122
3123 mod = mod->next;
3124 }
3125
3126 /* Don't do any further processing if the buffer was modified -
3127 * otherwise the code will end up modifying a chunk that was
3128 * just added.
3129 */
3130 if (mod != NULL)
3131 break; /* out of switch */
3132 }
3133
3134 /* If we get to here then this chunk may need to be modified. To
3135 * do this it must be less than 1024 bytes in total size, otherwise
3136 * it just gets flushed.
3137 */
3138 if (len+12 <= sizeof pm->buffer)
3139 {
3140 png_size_t s = len+12-pm->buffer_count;
3141 store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
3142 pm->buffer_count = len+12;
3143
3144 /* Check for a modification, else leave it be. */
3145 mod = pm->modifications;
3146 while (mod != NULL)
3147 {
3148 if (mod->chunk == chunk)
3149 {
3150 if (mod->modify_fn == NULL)
3151 {
3152 /* Remove this chunk */
3153 pm->buffer_count = pm->buffer_position = 0;
3154 mod->removed = 1;
3155 break; /* Terminate the while loop */
3156 }
3157
3158 else if ((*mod->modify_fn)(pm, mod, 0))
3159 {
3160 mod->modified = 1;
3161 /* The chunk may have been removed: */
3162 if (pm->buffer_count == 0)
3163 {
3164 pm->buffer_position = 0;
3165 break;
3166 }
3167 modifier_setbuffer(pm);
3168 }
3169 }
3170
3171 mod = mod->next;
3172 }
3173 }
3174
3175 else
3176 pm->flush = len+12 - pm->buffer_count; /* data + crc */
3177
3178 /* Take the data from the buffer (if there is any). */
3179 break;
3180 }
3181
3182 /* Here to read from the modifier buffer (not directly from
3183 * the store, as in the flush case above.)
3184 */
3185 cb = pm->buffer_count - pm->buffer_position;
3186
3187 if (cb > st)
3188 cb = st;
3189
3190 memcpy(pb, pm->buffer + pm->buffer_position, cb);
3191 st -= cb;
3192 pb += cb;
3193 pm->buffer_position += cb;
3194 }
3195}
3196
3197/* The callback: */
3198static void PNGCBAPI
3199modifier_read(png_structp ppIn, png_bytep pb, png_size_t st)
3200{
3201 png_const_structp pp = ppIn;
3202 png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
3203
3204 if (pm == NULL || pm->this.pread != pp)
3205 png_error(pp, "bad modifier_read call");
3206
3207 modifier_read_imp(pm, pb, st);
3208}
3209
3210/* Like store_progressive_read but the data is getting changed as we go so we
3211 * need a local buffer.
3212 */
3213static void
3214modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
3215{
3216 if (pm->this.pread != pp || pm->this.current == NULL ||
3217 pm->this.next == NULL)
3218 png_error(pp, "store state damaged (progressive)");
3219
3220 /* This is another Horowitz and Hill random noise generator. In this case
3221 * the aim is to stress the progressive reader with truly horrible variable
3222 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
3223 * is generated. We could probably just count from 1 to 32767 and get as
3224 * good a result.
3225 */
3226 for (;;)
3227 {
3228 static png_uint_32 noise = 1;
3229 png_size_t cb, cbAvail;
3230 png_byte buffer[512];
3231
3232 /* Generate 15 more bits of stuff: */
3233 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
3234 cb = noise & 0x1ff;
3235
3236 /* Check that this number of bytes are available (in the current buffer.)
3237 * (This doesn't quite work - the modifier might delete a chunk; unlikely
3238 * but possible, it doesn't happen at present because the modifier only
3239 * adds chunks to standard images.)
3240 */
3241 cbAvail = store_read_buffer_avail(&pm->this);
3242 if (pm->buffer_count > pm->buffer_position)
3243 cbAvail += pm->buffer_count - pm->buffer_position;
3244
3245 if (cb > cbAvail)
3246 {
3247 /* Check for EOF: */
3248 if (cbAvail == 0)
3249 break;
3250
3251 cb = cbAvail;
3252 }
3253
3254 modifier_read_imp(pm, buffer, cb);
3255 png_process_data(pp, pi, buffer, cb);
3256 }
3257
3258 /* Check the invariants at the end (if this fails it's a problem in this
3259 * file!)
3260 */
3261 if (pm->buffer_count > pm->buffer_position ||
3262 pm->this.next != &pm->this.current->data ||
3263 pm->this.readpos < pm->this.current->datacount)
3264 png_error(pp, "progressive read implementation error");
3265}
3266
3267/* Set up a modifier. */
3268static png_structp
3269set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
3270 const char *name)
3271{
3272 /* Do this first so that the modifier fields are cleared even if an error
3273 * happens allocating the png_struct. No allocation is done here so no
3274 * cleanup is required.
3275 */
3276 pm->state = modifier_start;
3277 pm->bit_depth = 0;
3278 pm->colour_type = 255;
3279
3280 pm->pending_len = 0;
3281 pm->pending_chunk = 0;
3282 pm->flush = 0;
3283 pm->buffer_count = 0;
3284 pm->buffer_position = 0;
3285
3286 return set_store_for_read(&pm->this, ppi, id, name);
3287}
3288
3289
3290/******************************** MODIFICATIONS *******************************/
3291/* Standard modifications to add chunks. These do not require the _SUPPORTED
3292 * macros because the chunks can be there regardless of whether this specific
3293 * libpng supports them.
3294 */
3295typedef struct gama_modification
3296{
3297 png_modification this;
3298 png_fixed_point gamma;
3299} gama_modification;
3300
3301static int
3302gama_modify(png_modifier *pm, png_modification *me, int add)
3303{
3304 UNUSED(add)
3305 /* This simply dumps the given gamma value into the buffer. */
3306 png_save_uint_32(pm->buffer, 4);
3307 png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
3308 png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
3309 return 1;
3310}
3311
3312static void
3313gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
3314{
3315 double g;
3316
3317 modification_init(&me->this);
3318 me->this.chunk = CHUNK_gAMA;
3319 me->this.modify_fn = gama_modify;
3320 me->this.add = CHUNK_PLTE;
3321 g = fix(gammad);
3322 me->gamma = (png_fixed_point)g;
3323 me->this.next = pm->modifications;
3324 pm->modifications = &me->this;
3325}
3326
3327typedef struct chrm_modification
3328{
3329 png_modification this;
3330 const color_encoding *encoding;
3331 png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
3332} chrm_modification;
3333
3334static int
3335chrm_modify(png_modifier *pm, png_modification *me, int add)
3336{
3337 UNUSED(add)
3338 /* As with gAMA this just adds the required cHRM chunk to the buffer. */
3339 png_save_uint_32(pm->buffer , 32);
3340 png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
3341 png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
3342 png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
3343 png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
3344 png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
3345 png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
3346 png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
3347 png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
3348 png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
3349 return 1;
3350}
3351
3352static void
3353chrm_modification_init(chrm_modification *me, png_modifier *pm,
3354 const color_encoding *encoding)
3355{
3356 CIE_color white = white_point(encoding);
3357
3358 /* Original end points: */
3359 me->encoding = encoding;
3360
3361 /* Chromaticities (in fixed point): */
3362 me->wx = fix(chromaticity_x(white));
3363 me->wy = fix(chromaticity_y(white));
3364
3365 me->rx = fix(chromaticity_x(encoding->red));
3366 me->ry = fix(chromaticity_y(encoding->red));
3367 me->gx = fix(chromaticity_x(encoding->green));
3368 me->gy = fix(chromaticity_y(encoding->green));
3369 me->bx = fix(chromaticity_x(encoding->blue));
3370 me->by = fix(chromaticity_y(encoding->blue));
3371
3372 modification_init(&me->this);
3373 me->this.chunk = CHUNK_cHRM;
3374 me->this.modify_fn = chrm_modify;
3375 me->this.add = CHUNK_PLTE;
3376 me->this.next = pm->modifications;
3377 pm->modifications = &me->this;
3378}
3379
3380typedef struct srgb_modification
3381{
3382 png_modification this;
3383 png_byte intent;
3384} srgb_modification;
3385
3386static int
3387srgb_modify(png_modifier *pm, png_modification *me, int add)
3388{
3389 UNUSED(add)
3390 /* As above, ignore add and just make a new chunk */
3391 png_save_uint_32(pm->buffer, 1);
3392 png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
3393 pm->buffer[8] = ((srgb_modification*)me)->intent;
3394 return 1;
3395}
3396
3397static void
3398srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
3399{
3400 modification_init(&me->this);
3401 me->this.chunk = CHUNK_sBIT;
3402
3403 if (intent <= 3) /* if valid, else *delete* sRGB chunks */
3404 {
3405 me->this.modify_fn = srgb_modify;
3406 me->this.add = CHUNK_PLTE;
3407 me->intent = intent;
3408 }
3409
3410 else
3411 {
3412 me->this.modify_fn = 0;
3413 me->this.add = 0;
3414 me->intent = 0;
3415 }
3416
3417 me->this.next = pm->modifications;
3418 pm->modifications = &me->this;
3419}
3420
3421#ifdef PNG_READ_GAMMA_SUPPORTED
3422typedef struct sbit_modification
3423{
3424 png_modification this;
3425 png_byte sbit;
3426} sbit_modification;
3427
3428static int
3429sbit_modify(png_modifier *pm, png_modification *me, int add)
3430{
3431 png_byte sbit = ((sbit_modification*)me)->sbit;
3432 if (pm->bit_depth > sbit)
3433 {
3434 int cb = 0;
3435 switch (pm->colour_type)
3436 {
3437 case 0:
3438 cb = 1;
3439 break;
3440
3441 case 2:
3442 case 3:
3443 cb = 3;
3444 break;
3445
3446 case 4:
3447 cb = 2;
3448 break;
3449
3450 case 6:
3451 cb = 4;
3452 break;
3453
3454 default:
3455 png_error(pm->this.pread,
3456 "unexpected colour type in sBIT modification");
3457 }
3458
3459 png_save_uint_32(pm->buffer, cb);
3460 png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
3461
3462 while (cb > 0)
3463 (pm->buffer+8)[--cb] = sbit;
3464
3465 return 1;
3466 }
3467 else if (!add)
3468 {
3469 /* Remove the sBIT chunk */
3470 pm->buffer_count = pm->buffer_position = 0;
3471 return 1;
3472 }
3473 else
3474 return 0; /* do nothing */
3475}
3476
3477static void
3478sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
3479{
3480 modification_init(&me->this);
3481 me->this.chunk = CHUNK_sBIT;
3482 me->this.modify_fn = sbit_modify;
3483 me->this.add = CHUNK_PLTE;
3484 me->sbit = sbit;
3485 me->this.next = pm->modifications;
3486 pm->modifications = &me->this;
3487}
3488#endif /* PNG_READ_GAMMA_SUPPORTED */
3489#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
3490
3491/***************************** STANDARD PNG FILES *****************************/
3492/* Standard files - write and save standard files. */
3493/* There are two basic forms of standard images. Those which attempt to have
3494 * all the possible pixel values (not possible for 16bpp images, but a range of
3495 * values are produced) and those which have a range of image sizes. The former
3496 * are used for testing transforms, in particular gamma correction and bit
3497 * reduction and increase. The latter are reserved for testing the behavior of
3498 * libpng with respect to 'odd' image sizes - particularly small images where
3499 * rows become 1 byte and interlace passes disappear.
3500 *
3501 * The first, most useful, set are the 'transform' images, the second set of
3502 * small images are the 'size' images.
3503 *
3504 * The transform files are constructed with rows which fit into a 1024 byte row
3505 * buffer. This makes allocation easier below. Further regardless of the file
3506 * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
3507 *
3508 * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
3509 * and with an ID derived from the colour type, bit depth and interlace type
3510 * as above (FILEID). The width (128) and height (variable) are not stored in
3511 * the FILEID - instead the fields are set to 0, indicating a transform file.
3512 *
3513 * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
3514 * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
3515 * height of 16 rows. The width and height are stored in the FILEID and, being
3516 * non-zero, indicate a size file.
3517 *
3518 * Because the PNG filter code is typically the largest CPU consumer within
3519 * libpng itself there is a tendency to attempt to optimize it. This results in
3520 * special case code which needs to be validated. To cause this to happen the
3521 * 'size' images are made to use each possible filter, in so far as this is
3522 * possible for smaller images.
3523 *
3524 * For palette image (colour type 3) multiple transform images are stored with
3525 * the same bit depth to allow testing of more colour combinations -
3526 * particularly important for testing the gamma code because libpng uses a
3527 * different code path for palette images. For size images a single palette is
3528 * used.
3529 */
3530
3531/* Make a 'standard' palette. Because there are only 256 entries in a palette
3532 * (maximum) this actually makes a random palette in the hope that enough tests
3533 * will catch enough errors. (Note that the same palette isn't produced every
3534 * time for the same test - it depends on what previous tests have been run -
3535 * but a given set of arguments to pngvalid will always produce the same palette
3536 * at the same test! This is why pseudo-random number generators are useful for
3537 * testing.)
3538 *
3539 * The store must be open for write when this is called, otherwise an internal
3540 * error will occur. This routine contains its own magic number seed, so the
3541 * palettes generated don't change if there are intervening errors (changing the
3542 * calls to the store_mark seed.)
3543 */
3544static store_palette_entry *
3545make_standard_palette(png_store* ps, int npalette, int do_tRNS)
3546{
3547 static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
3548
3549 int i = 0;
3550 png_byte values[256][4];
3551
3552 /* Always put in black and white plus the six primary and secondary colors.
3553 */
3554 for (; i<8; ++i)
3555 {
3556 values[i][1] = (png_byte)((i&1) ? 255U : 0U);
3557 values[i][2] = (png_byte)((i&2) ? 255U : 0U);
3558 values[i][3] = (png_byte)((i&4) ? 255U : 0U);
3559 }
3560
3561 /* Then add 62 grays (one quarter of the remaining 256 slots). */
3562 {
3563 int j = 0;
3564 png_byte random_bytes[4];
3565 png_byte need[256];
3566
3567 need[0] = 0; /*got black*/
3568 memset(need+1, 1, (sizeof need)-2); /*need these*/
3569 need[255] = 0; /*but not white*/
3570
3571 while (i<70)
3572 {
3573 png_byte b;
3574
3575 if (j==0)
3576 {
3577 make_four_random_bytes(palette_seed, random_bytes);
3578 j = 4;
3579 }
3580
3581 b = random_bytes[--j];
3582 if (need[b])
3583 {
3584 values[i][1] = b;
3585 values[i][2] = b;
3586 values[i++][3] = b;
3587 }
3588 }
3589 }
3590
3591 /* Finally add 192 colors at random - don't worry about matches to things we
3592 * already have, chance is less than 1/65536. Don't worry about grays,
3593 * chance is the same, so we get a duplicate or extra gray less than 1 time
3594 * in 170.
3595 */
3596 for (; i<256; ++i)
3597 make_four_random_bytes(palette_seed, values[i]);
3598
3599 /* Fill in the alpha values in the first byte. Just use all possible values
3600 * (0..255) in an apparently random order:
3601 */
3602 {
3603 store_palette_entry *palette;
3604 png_byte selector[4];
3605
3606 make_four_random_bytes(palette_seed, selector);
3607
3608 if (do_tRNS)
3609 for (i=0; i<256; ++i)
3610 values[i][0] = (png_byte)(i ^ selector[0]);
3611
3612 else
3613 for (i=0; i<256; ++i)
3614 values[i][0] = 255; /* no transparency/tRNS chunk */
3615
3616 /* 'values' contains 256 ARGB values, but we only need 'npalette'.
3617 * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
3618 * bit depth cases select colors at random, else it is difficult to have
3619 * a set of low bit depth palette test with any chance of a reasonable
3620 * range of colors. Do this by randomly permuting values into the low
3621 * 'npalette' entries using an XOR mask generated here. This also
3622 * permutes the npalette == 256 case in a potentially useful way (there is
3623 * no relationship between palette index and the color value therein!)
3624 */
3625 palette = store_write_palette(ps, npalette);
3626
3627 for (i=0; i<npalette; ++i)
3628 {
3629 palette[i].alpha = values[i ^ selector[1]][0];
3630 palette[i].red = values[i ^ selector[1]][1];
3631 palette[i].green = values[i ^ selector[1]][2];
3632 palette[i].blue = values[i ^ selector[1]][3];
3633 }
3634
3635 return palette;
3636 }
3637}
3638
3639/* Initialize a standard palette on a write stream. The 'do_tRNS' argument
3640 * indicates whether or not to also set the tRNS chunk.
3641 */
3642/* TODO: the png_structp here can probably be 'const' in the future */
3643static void
3644init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
3645 int do_tRNS)
3646{
3647 store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
3648
3649 {
3650 int i;
3651 png_color palette[256];
3652
3653 /* Set all entries to detect overread errors. */
3654 for (i=0; i<npalette; ++i)
3655 {
3656 palette[i].red = ppal[i].red;
3657 palette[i].green = ppal[i].green;
3658 palette[i].blue = ppal[i].blue;
3659 }
3660
3661 /* Just in case fill in the rest with detectable values: */
3662 for (; i<256; ++i)
3663 palette[i].red = palette[i].green = palette[i].blue = 42;
3664
3665 png_set_PLTE(pp, pi, palette, npalette);
3666 }
3667
3668 if (do_tRNS)
3669 {
3670 int i, j;
3671 png_byte tRNS[256];
3672
3673 /* Set all the entries, but skip trailing opaque entries */
3674 for (i=j=0; i<npalette; ++i)
3675 if ((tRNS[i] = ppal[i].alpha) < 255)
3676 j = i+1;
3677
3678 /* Fill in the remainder with a detectable value: */
3679 for (; i<256; ++i)
3680 tRNS[i] = 24;
3681
3682#ifdef PNG_WRITE_tRNS_SUPPORTED
3683 if (j > 0)
3684 png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
3685#endif
3686 }
3687}
3688
3689#ifdef PNG_WRITE_tRNS_SUPPORTED
3690static void
3691set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type,
3692 const int bit_depth)
3693{
3694 /* To make this useful the tRNS color needs to match at least one pixel.
3695 * Random values are fine for gray, including the 16-bit case where we know
3696 * that the test image contains all the gray values. For RGB we need more
3697 * method as only 65536 different RGB values are generated.
3698 */
3699 png_color_16 tRNS;
3700 const png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1);
3701
3702 R8(tRNS); /* makes unset fields random */
3703
3704 if (colour_type & 2/*RGB*/)
3705 {
3706 if (bit_depth == 8)
3707 {
3708 tRNS.red = random_u16();
3709 tRNS.green = random_u16();
3710 tRNS.blue = tRNS.red ^ tRNS.green;
3711 tRNS.red &= mask;
3712 tRNS.green &= mask;
3713 tRNS.blue &= mask;
3714 }
3715
3716 else /* bit_depth == 16 */
3717 {
3718 tRNS.red = random_u16();
3719 tRNS.green = (png_uint_16)(tRNS.red * 257);
3720 tRNS.blue = (png_uint_16)(tRNS.green * 17);
3721 }
3722 }
3723
3724 else
3725 {
3726 tRNS.gray = random_u16();
3727 tRNS.gray &= mask;
3728 }
3729
3730 png_set_tRNS(pp, pi, NULL, 0, &tRNS);
3731}
3732#endif
3733
3734/* The number of passes is related to the interlace type. There was no libpng
3735 * API to determine this prior to 1.5, so we need an inquiry function:
3736 */
3737static int
3738npasses_from_interlace_type(png_const_structp pp, int interlace_type)
3739{
3740 switch (interlace_type)
3741 {
3742 default:
3743 png_error(pp, "invalid interlace type");
3744
3745 case PNG_INTERLACE_NONE:
3746 return 1;
3747
3748 case PNG_INTERLACE_ADAM7:
3749 return PNG_INTERLACE_ADAM7_PASSES;
3750 }
3751}
3752
3753static unsigned int
3754bit_size(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3755{
3756 switch (colour_type)
3757 {
3758 default: png_error(pp, "invalid color type");
3759
3760 case 0: return bit_depth;
3761
3762 case 2: return 3*bit_depth;
3763
3764 case 3: return bit_depth;
3765
3766 case 4: return 2*bit_depth;
3767
3768 case 6: return 4*bit_depth;
3769 }
3770}
3771
3772#define TRANSFORM_WIDTH 128U
3773#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
3774#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
3775#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
3776#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
3777
3778static size_t
3779transform_rowsize(png_const_structp pp, png_byte colour_type,
3780 png_byte bit_depth)
3781{
3782 return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
3783}
3784
3785/* transform_width(pp, colour_type, bit_depth) current returns the same number
3786 * every time, so just use a macro:
3787 */
3788#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
3789
3790static png_uint_32
3791transform_height(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3792{
3793 switch (bit_size(pp, colour_type, bit_depth))
3794 {
3795 case 1:
3796 case 2:
3797 case 4:
3798 return 1; /* Total of 128 pixels */
3799
3800 case 8:
3801 return 2; /* Total of 256 pixels/bytes */
3802
3803 case 16:
3804 return 512; /* Total of 65536 pixels */
3805
3806 case 24:
3807 case 32:
3808 return 512; /* 65536 pixels */
3809
3810 case 48:
3811 case 64:
3812 return 2048;/* 4 x 65536 pixels. */
3813# define TRANSFORM_HEIGHTMAX 2048
3814
3815 default:
3816 return 0; /* Error, will be caught later */
3817 }
3818}
3819
3820#ifdef PNG_READ_SUPPORTED
3821/* The following can only be defined here, now we have the definitions
3822 * of the transform image sizes.
3823 */
3824static png_uint_32
3825standard_width(png_const_structp pp, png_uint_32 id)
3826{
3827 png_uint_32 width = WIDTH_FROM_ID(id);
3828 UNUSED(pp)
3829
3830 if (width == 0)
3831 width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3832
3833 return width;
3834}
3835
3836static png_uint_32
3837standard_height(png_const_structp pp, png_uint_32 id)
3838{
3839 png_uint_32 height = HEIGHT_FROM_ID(id);
3840
3841 if (height == 0)
3842 height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3843
3844 return height;
3845}
3846
3847static png_uint_32
3848standard_rowsize(png_const_structp pp, png_uint_32 id)
3849{
3850 png_uint_32 width = standard_width(pp, id);
3851
3852 /* This won't overflow: */
3853 width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3854 return (width + 7) / 8;
3855}
3856#endif /* PNG_READ_SUPPORTED */
3857
3858static void
3859transform_row(png_const_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
3860 png_byte colour_type, png_byte bit_depth, png_uint_32 y)
3861{
3862 png_uint_32 v = y << 7;
3863 png_uint_32 i = 0;
3864
3865 switch (bit_size(pp, colour_type, bit_depth))
3866 {
3867 case 1:
3868 while (i<128/8) buffer[i] = (png_byte)(v & 0xff), v += 17, ++i;
3869 return;
3870
3871 case 2:
3872 while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i;
3873 return;
3874
3875 case 4:
3876 while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i;
3877 return;
3878
3879 case 8:
3880 /* 256 bytes total, 128 bytes in each row set as follows: */
3881 while (i<128) buffer[i] = (png_byte)(v & 0xff), ++v, ++i;
3882 return;
3883
3884 case 16:
3885 /* Generate all 65536 pixel values in order, which includes the 8 bit
3886 * GA case as well as the 16 bit G case.
3887 */
3888 while (i<128)
3889 {
3890 buffer[2*i] = (png_byte)((v>>8) & 0xff);
3891 buffer[2*i+1] = (png_byte)(v & 0xff);
3892 ++v;
3893 ++i;
3894 }
3895
3896 return;
3897
3898 case 24:
3899 /* 65535 pixels, but rotate the values. */
3900 while (i<128)
3901 {
3902 /* Three bytes per pixel, r, g, b, make b by r^g */
3903 buffer[3*i+0] = (png_byte)((v >> 8) & 0xff);
3904 buffer[3*i+1] = (png_byte)(v & 0xff);
3905 buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff);
3906 ++v;
3907 ++i;
3908 }
3909
3910 return;
3911
3912 case 32:
3913 /* 65535 pixels, r, g, b, a; just replicate */
3914 while (i<128)
3915 {
3916 buffer[4*i+0] = (png_byte)((v >> 8) & 0xff);
3917 buffer[4*i+1] = (png_byte)(v & 0xff);
3918 buffer[4*i+2] = (png_byte)((v >> 8) & 0xff);
3919 buffer[4*i+3] = (png_byte)(v & 0xff);
3920 ++v;
3921 ++i;
3922 }
3923
3924 return;
3925
3926 case 48:
3927 /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
3928 * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
3929 */
3930 while (i<128)
3931 {
3932 png_uint_32 t = v++;
3933 buffer[6*i+0] = (png_byte)((t >> 8) & 0xff);
3934 buffer[6*i+1] = (png_byte)(t & 0xff);
3935 t *= 257;
3936 buffer[6*i+2] = (png_byte)((t >> 8) & 0xff);
3937 buffer[6*i+3] = (png_byte)(t & 0xff);
3938 t *= 17;
3939 buffer[6*i+4] = (png_byte)((t >> 8) & 0xff);
3940 buffer[6*i+5] = (png_byte)(t & 0xff);
3941 ++i;
3942 }
3943
3944 return;
3945
3946 case 64:
3947 /* As above in the 32 bit case. */
3948 while (i<128)
3949 {
3950 png_uint_32 t = v++;
3951 buffer[8*i+0] = (png_byte)((t >> 8) & 0xff);
3952 buffer[8*i+1] = (png_byte)(t & 0xff);
3953 buffer[8*i+4] = (png_byte)((t >> 8) & 0xff);
3954 buffer[8*i+5] = (png_byte)(t & 0xff);
3955 t *= 257;
3956 buffer[8*i+2] = (png_byte)((t >> 8) & 0xff);
3957 buffer[8*i+3] = (png_byte)(t & 0xff);
3958 buffer[8*i+6] = (png_byte)((t >> 8) & 0xff);
3959 buffer[8*i+7] = (png_byte)(t & 0xff);
3960 ++i;
3961 }
3962 return;
3963
3964 default:
3965 break;
3966 }
3967
3968 png_error(pp, "internal error");
3969}
3970
3971/* This is just to do the right cast - could be changed to a function to check
3972 * 'bd' but there isn't much point.
3973 */
3974#define DEPTH(bd) ((png_byte)(1U << (bd)))
3975
3976/* This is just a helper for compiling on minimal systems with no write
3977 * interlacing support. If there is no write interlacing we can't generate test
3978 * cases with interlace:
3979 */
3980#ifdef PNG_WRITE_INTERLACING_SUPPORTED
3981# define INTERLACE_LAST PNG_INTERLACE_LAST
3982# define check_interlace_type(type) ((void)(type))
3983# define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp)
3984# define do_own_interlace 0
3985#elif PNG_LIBPNG_VER < 10700
3986# define set_write_interlace_handling(pp,type) (1)
3987static void
3988check_interlace_type(int const interlace_type)
3989{
3990 /* Prior to 1.7.0 libpng does not support the write of an interlaced image
3991 * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the
3992 * code here does the pixel interlace itself, so:
3993 */
3994 if (interlace_type != PNG_INTERLACE_NONE)
3995 {
3996 /* This is an internal error - --interlace tests should be skipped, not
3997 * attempted.
3998 */
3999 fprintf(stderr, "pngvalid: no interlace support\n");
4000 exit(99);
4001 }
4002}
4003# define INTERLACE_LAST (PNG_INTERLACE_NONE+1)
4004# define do_own_interlace 0
4005#else /* libpng 1.7+ */
4006# define set_write_interlace_handling(pp,type)\
4007 npasses_from_interlace_type(pp,type)
4008# define check_interlace_type(type) ((void)(type))
4009# define INTERLACE_LAST PNG_INTERLACE_LAST
4010# define do_own_interlace 1
4011#endif /* WRITE_INTERLACING tests */
4012
4013#if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
4014# define CAN_WRITE_INTERLACE 1
4015#else
4016# define CAN_WRITE_INTERLACE 0
4017#endif
4018
4019/* Do the same thing for read interlacing; this controls whether read tests do
4020 * their own de-interlace or use libpng.
4021 */
4022#ifdef PNG_READ_INTERLACING_SUPPORTED
4023# define do_read_interlace 0
4024#else /* no libpng read interlace support */
4025# define do_read_interlace 1
4026#endif
4027/* The following two routines use the PNG interlace support macros from
4028 * png.h to interlace or deinterlace rows.
4029 */
4030static void
4031interlace_row(png_bytep buffer, png_const_bytep imageRow,
4032 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4033{
4034 png_uint_32 xin, xout, xstep;
4035
4036 /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
4037 * code is presented this way to make it easier to understand. In practice
4038 * consult the code in the libpng source to see other ways of doing this.
4039 *
4040 * It is OK for buffer and imageRow to be identical, because 'xin' moves
4041 * faster than 'xout' and we copy up.
4042 */
4043 xin = PNG_PASS_START_COL(pass);
4044 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4045
4046 for (xout=0; xin<w; xin+=xstep)
4047 {
4048 pixel_copy(buffer, xout, imageRow, xin, pixel_size, littleendian);
4049 ++xout;
4050 }
4051}
4052
4053#ifdef PNG_READ_SUPPORTED
4054static void
4055deinterlace_row(png_bytep buffer, png_const_bytep row,
4056 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4057{
4058 /* The inverse of the above, 'row' is part of row 'y' of the output image,
4059 * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
4060 * the pixels of row into buffer and return the number written (to allow
4061 * this to be checked).
4062 */
4063 png_uint_32 xin, xout, xstep;
4064
4065 xout = PNG_PASS_START_COL(pass);
4066 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4067
4068 for (xin=0; xout<w; xout+=xstep)
4069 {
4070 pixel_copy(buffer, xout, row, xin, pixel_size, littleendian);
4071 ++xin;
4072 }
4073}
4074#endif /* PNG_READ_SUPPORTED */
4075
4076/* Make a standardized image given an image colour type, bit depth and
4077 * interlace type. The standard images have a very restricted range of
4078 * rows and heights and are used for testing transforms rather than image
4079 * layout details. See make_size_images below for a way to make images
4080 * that test odd sizes along with the libpng interlace handling.
4081 */
4082#ifdef PNG_WRITE_FILTER_SUPPORTED
4083static void
4084choose_random_filter(png_structp pp, int start)
4085{
4086 /* Choose filters randomly except that on the very first row ensure that
4087 * there is at least one previous row filter.
4088 */
4089 int filters = PNG_ALL_FILTERS & random_mod(256U);
4090
4091 /* There may be no filters; skip the setting. */
4092 if (filters != 0)
4093 {
4094 if (start && filters < PNG_FILTER_UP)
4095 filters |= PNG_FILTER_UP;
4096
4097 png_set_filter(pp, 0/*method*/, filters);
4098 }
4099}
4100#else /* !WRITE_FILTER */
4101# define choose_random_filter(pp, start) ((void)0)
4102#endif /* !WRITE_FILTER */
4103
4104static void
4105make_transform_image(png_store* const ps, png_byte const colour_type,
4106 png_byte const bit_depth, unsigned int palette_number,
4107 int interlace_type, png_const_charp name)
4108{
4109 context(ps, fault);
4110
4111 check_interlace_type(interlace_type);
4112
4113 Try
4114 {
4115 png_infop pi;
4116 png_structp pp = set_store_for_write(ps, &pi, name);
4117 png_uint_32 h, w;
4118
4119 /* In the event of a problem return control to the Catch statement below
4120 * to do the clean up - it is not possible to 'return' directly from a Try
4121 * block.
4122 */
4123 if (pp == NULL)
4124 Throw ps;
4125
4126 w = transform_width(pp, colour_type, bit_depth);
4127 h = transform_height(pp, colour_type, bit_depth);
4128
4129 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4130 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4131
4132#ifdef PNG_TEXT_SUPPORTED
4133# if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED)
4134# define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt
4135# else
4136# define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE
4137# endif
4138 {
4139 static char key[] = "image name"; /* must be writeable */
4140 size_t pos;
4141 png_text text;
4142 char copy[FILE_NAME_SIZE];
4143
4144 /* Use a compressed text string to test the correct interaction of text
4145 * compression and IDAT compression.
4146 */
4147 text.compression = TEXT_COMPRESSION;
4148 text.key = key;
4149 /* Yuck: the text must be writable! */
4150 pos = safecat(copy, sizeof copy, 0, ps->wname);
4151 text.text = copy;
4152 text.text_length = pos;
4153 text.itxt_length = 0;
4154 text.lang = 0;
4155 text.lang_key = 0;
4156
4157 png_set_text(pp, pi, &text, 1);
4158 }
4159#endif
4160
4161 if (colour_type == 3) /* palette */
4162 init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
4163
4164# ifdef PNG_WRITE_tRNS_SUPPORTED
4165 else if (palette_number)
4166 set_random_tRNS(pp, pi, colour_type, bit_depth);
4167# endif
4168
4169 png_write_info(pp, pi);
4170
4171 if (png_get_rowbytes(pp, pi) !=
4172 transform_rowsize(pp, colour_type, bit_depth))
4173 png_error(pp, "transform row size incorrect");
4174
4175 else
4176 {
4177 /* Somewhat confusingly this must be called *after* png_write_info
4178 * because if it is called before, the information in *pp has not been
4179 * updated to reflect the interlaced image.
4180 */
4181 int npasses = set_write_interlace_handling(pp, interlace_type);
4182 int pass;
4183
4184 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4185 png_error(pp, "write: png_set_interlace_handling failed");
4186
4187 for (pass=0; pass<npasses; ++pass)
4188 {
4189 png_uint_32 y;
4190
4191 /* do_own_interlace is a pre-defined boolean (a #define) which is
4192 * set if we have to work out the interlaced rows here.
4193 */
4194 for (y=0; y<h; ++y)
4195 {
4196 png_byte buffer[TRANSFORM_ROWMAX];
4197
4198 transform_row(pp, buffer, colour_type, bit_depth, y);
4199
4200# if do_own_interlace
4201 /* If do_own_interlace *and* the image is interlaced we need a
4202 * reduced interlace row; this may be reduced to empty.
4203 */
4204 if (interlace_type == PNG_INTERLACE_ADAM7)
4205 {
4206 /* The row must not be written if it doesn't exist, notice
4207 * that there are two conditions here, either the row isn't
4208 * ever in the pass or the row would be but isn't wide
4209 * enough to contribute any pixels. In fact the wPass test
4210 * can be used to skip the whole y loop in this case.
4211 */
4212 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4213 PNG_PASS_COLS(w, pass) > 0)
4214 interlace_row(buffer, buffer,
4215 bit_size(pp, colour_type, bit_depth), w, pass,
4216 0/*data always bigendian*/);
4217 else
4218 continue;
4219 }
4220# endif /* do_own_interlace */
4221
4222 choose_random_filter(pp, pass == 0 && y == 0);
4223 png_write_row(pp, buffer);
4224 }
4225 }
4226 }
4227
4228#ifdef PNG_TEXT_SUPPORTED
4229 {
4230 static char key[] = "end marker";
4231 static char comment[] = "end";
4232 png_text text;
4233
4234 /* Use a compressed text string to test the correct interaction of text
4235 * compression and IDAT compression.
4236 */
4237 text.compression = TEXT_COMPRESSION;
4238 text.key = key;
4239 text.text = comment;
4240 text.text_length = (sizeof comment)-1;
4241 text.itxt_length = 0;
4242 text.lang = 0;
4243 text.lang_key = 0;
4244
4245 png_set_text(pp, pi, &text, 1);
4246 }
4247#endif
4248
4249 png_write_end(pp, pi);
4250
4251 /* And store this under the appropriate id, then clean up. */
4252 store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
4253 interlace_type, 0, 0, 0));
4254
4255 store_write_reset(ps);
4256 }
4257
4258 Catch(fault)
4259 {
4260 /* Use the png_store returned by the exception. This may help the compiler
4261 * because 'ps' is not used in this branch of the setjmp. Note that fault
4262 * and ps will always be the same value.
4263 */
4264 store_write_reset(fault);
4265 }
4266}
4267
4268static void
4269make_transform_images(png_modifier *pm)
4270{
4271 png_byte colour_type = 0;
4272 png_byte bit_depth = 0;
4273 unsigned int palette_number = 0;
4274
4275 /* This is in case of errors. */
4276 safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images");
4277
4278 /* Use next_format to enumerate all the combinations we test, including
4279 * generating multiple low bit depth palette images. Non-A images (palette
4280 * and direct) are created with and without tRNS chunks.
4281 */
4282 while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1))
4283 {
4284 int interlace_type;
4285
4286 for (interlace_type = PNG_INTERLACE_NONE;
4287 interlace_type < INTERLACE_LAST; ++interlace_type)
4288 {
4289 char name[FILE_NAME_SIZE];
4290
4291 standard_name(name, sizeof name, 0, colour_type, bit_depth,
4292 palette_number, interlace_type, 0, 0, do_own_interlace);
4293 make_transform_image(&pm->this, colour_type, bit_depth, palette_number,
4294 interlace_type, name);
4295 }
4296 }
4297}
4298
4299/* Build a single row for the 'size' test images; this fills in only the
4300 * first bit_width bits of the sample row.
4301 */
4302static void
4303size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
4304{
4305 /* height is in the range 1 to 16, so: */
4306 y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
4307 /* the following ensures bits are set in small images: */
4308 y ^= 0xA5;
4309
4310 while (bit_width >= 8)
4311 *buffer++ = (png_byte)y++, bit_width -= 8;
4312
4313 /* There may be up to 7 remaining bits, these go in the most significant
4314 * bits of the byte.
4315 */
4316 if (bit_width > 0)
4317 {
4318 png_uint_32 mask = (1U<<(8-bit_width))-1;
4319 *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
4320 }
4321}
4322
4323static void
4324make_size_image(png_store* const ps, png_byte const colour_type,
4325 png_byte const bit_depth, int const interlace_type,
4326 png_uint_32 const w, png_uint_32 const h,
4327 int const do_interlace)
4328{
4329 context(ps, fault);
4330
4331 check_interlace_type(interlace_type);
4332
4333 Try
4334 {
4335 png_infop pi;
4336 png_structp pp;
4337 unsigned int pixel_size;
4338
4339 /* Make a name and get an appropriate id for the store: */
4340 char name[FILE_NAME_SIZE];
4341 const png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
4342 interlace_type, w, h, do_interlace);
4343
4344 standard_name_from_id(name, sizeof name, 0, id);
4345 pp = set_store_for_write(ps, &pi, name);
4346
4347 /* In the event of a problem return control to the Catch statement below
4348 * to do the clean up - it is not possible to 'return' directly from a Try
4349 * block.
4350 */
4351 if (pp == NULL)
4352 Throw ps;
4353
4354 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4355 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4356
4357#ifdef PNG_TEXT_SUPPORTED
4358 {
4359 static char key[] = "image name"; /* must be writeable */
4360 size_t pos;
4361 png_text text;
4362 char copy[FILE_NAME_SIZE];
4363
4364 /* Use a compressed text string to test the correct interaction of text
4365 * compression and IDAT compression.
4366 */
4367 text.compression = TEXT_COMPRESSION;
4368 text.key = key;
4369 /* Yuck: the text must be writable! */
4370 pos = safecat(copy, sizeof copy, 0, ps->wname);
4371 text.text = copy;
4372 text.text_length = pos;
4373 text.itxt_length = 0;
4374 text.lang = 0;
4375 text.lang_key = 0;
4376
4377 png_set_text(pp, pi, &text, 1);
4378 }
4379#endif
4380
4381 if (colour_type == 3) /* palette */
4382 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4383
4384 png_write_info(pp, pi);
4385
4386 /* Calculate the bit size, divide by 8 to get the byte size - this won't
4387 * overflow because we know the w values are all small enough even for
4388 * a system where 'unsigned int' is only 16 bits.
4389 */
4390 pixel_size = bit_size(pp, colour_type, bit_depth);
4391 if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
4392 png_error(pp, "size row size incorrect");
4393
4394 else
4395 {
4396 int npasses = npasses_from_interlace_type(pp, interlace_type);
4397 png_uint_32 y;
4398 int pass;
4399 png_byte image[16][SIZE_ROWMAX];
4400
4401 /* To help consistent error detection make the parts of this buffer
4402 * that aren't set below all '1':
4403 */
4404 memset(image, 0xff, sizeof image);
4405
4406 if (!do_interlace &&
4407 npasses != set_write_interlace_handling(pp, interlace_type))
4408 png_error(pp, "write: png_set_interlace_handling failed");
4409
4410 /* Prepare the whole image first to avoid making it 7 times: */
4411 for (y=0; y<h; ++y)
4412 size_row(image[y], w * pixel_size, y);
4413
4414 for (pass=0; pass<npasses; ++pass)
4415 {
4416 /* The following two are for checking the macros: */
4417 const png_uint_32 wPass = PNG_PASS_COLS(w, pass);
4418
4419 /* If do_interlace is set we don't call png_write_row for every
4420 * row because some of them are empty. In fact, for a 1x1 image,
4421 * most of them are empty!
4422 */
4423 for (y=0; y<h; ++y)
4424 {
4425 png_const_bytep row = image[y];
4426 png_byte tempRow[SIZE_ROWMAX];
4427
4428 /* If do_interlace *and* the image is interlaced we
4429 * need a reduced interlace row; this may be reduced
4430 * to empty.
4431 */
4432 if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
4433 {
4434 /* The row must not be written if it doesn't exist, notice
4435 * that there are two conditions here, either the row isn't
4436 * ever in the pass or the row would be but isn't wide
4437 * enough to contribute any pixels. In fact the wPass test
4438 * can be used to skip the whole y loop in this case.
4439 */
4440 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
4441 {
4442 /* Set to all 1's for error detection (libpng tends to
4443 * set unset things to 0).
4444 */
4445 memset(tempRow, 0xff, sizeof tempRow);
4446 interlace_row(tempRow, row, pixel_size, w, pass,
4447 0/*data always bigendian*/);
4448 row = tempRow;
4449 }
4450 else
4451 continue;
4452 }
4453
4454# ifdef PNG_WRITE_FILTER_SUPPORTED
4455 /* Only get to here if the row has some pixels in it, set the
4456 * filters to 'all' for the very first row and thereafter to a
4457 * single filter. It isn't well documented, but png_set_filter
4458 * does accept a filter number (per the spec) as well as a bit
4459 * mask.
4460 *
4461 * The code now uses filters at random, except that on the first
4462 * row of an image it ensures that a previous row filter is in
4463 * the set so that libpng allocates the row buffer.
4464 */
4465 {
4466 int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST);
4467
4468 if (pass == 0 && y == 0 &&
4469 (filters < PNG_FILTER_UP || w == 1U))
4470 filters |= PNG_FILTER_UP;
4471
4472 png_set_filter(pp, 0/*method*/, filters);
4473 }
4474# endif
4475
4476 png_write_row(pp, row);
4477 }
4478 }
4479 }
4480
4481#ifdef PNG_TEXT_SUPPORTED
4482 {
4483 static char key[] = "end marker";
4484 static char comment[] = "end";
4485 png_text text;
4486
4487 /* Use a compressed text string to test the correct interaction of text
4488 * compression and IDAT compression.
4489 */
4490 text.compression = TEXT_COMPRESSION;
4491 text.key = key;
4492 text.text = comment;
4493 text.text_length = (sizeof comment)-1;
4494 text.itxt_length = 0;
4495 text.lang = 0;
4496 text.lang_key = 0;
4497
4498 png_set_text(pp, pi, &text, 1);
4499 }
4500#endif
4501
4502 png_write_end(pp, pi);
4503
4504 /* And store this under the appropriate id, then clean up. */
4505 store_storefile(ps, id);
4506
4507 store_write_reset(ps);
4508 }
4509
4510 Catch(fault)
4511 {
4512 /* Use the png_store returned by the exception. This may help the compiler
4513 * because 'ps' is not used in this branch of the setjmp. Note that fault
4514 * and ps will always be the same value.
4515 */
4516 store_write_reset(fault);
4517 }
4518}
4519
4520static void
4521make_size(png_store* const ps, png_byte const colour_type, int bdlo,
4522 int const bdhi)
4523{
4524 for (; bdlo <= bdhi; ++bdlo)
4525 {
4526 png_uint_32 width;
4527
4528 for (width = 1; width <= 16; ++width)
4529 {
4530 png_uint_32 height;
4531
4532 for (height = 1; height <= 16; ++height)
4533 {
4534 /* The four combinations of DIY interlace and interlace or not -
4535 * no interlace + DIY should be identical to no interlace with
4536 * libpng doing it.
4537 */
4538 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4539 width, height, 0);
4540 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4541 width, height, 1);
4542# ifdef PNG_WRITE_INTERLACING_SUPPORTED
4543 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4544 width, height, 0);
4545# endif
4546# if CAN_WRITE_INTERLACE
4547 /* 1.7.0 removes the hack that prevented app write of an interlaced
4548 * image if WRITE_INTERLACE was not supported
4549 */
4550 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4551 width, height, 1);
4552# endif
4553 }
4554 }
4555 }
4556}
4557
4558static void
4559make_size_images(png_store *ps)
4560{
4561 /* This is in case of errors. */
4562 safecat(ps->test, sizeof ps->test, 0, "make size images");
4563
4564 /* Arguments are colour_type, low bit depth, high bit depth
4565 */
4566 make_size(ps, 0, 0, WRITE_BDHI);
4567 make_size(ps, 2, 3, WRITE_BDHI);
4568 make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
4569 make_size(ps, 4, 3, WRITE_BDHI);
4570 make_size(ps, 6, 3, WRITE_BDHI);
4571}
4572
4573#ifdef PNG_READ_SUPPORTED
4574/* Return a row based on image id and 'y' for checking: */
4575static void
4576standard_row(png_const_structp pp, png_byte std[STANDARD_ROWMAX],
4577 png_uint_32 id, png_uint_32 y)
4578{
4579 if (WIDTH_FROM_ID(id) == 0)
4580 transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
4581 else
4582 size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
4583 DEPTH_FROM_ID(id)), y);
4584}
4585#endif /* PNG_READ_SUPPORTED */
4586
4587/* Tests - individual test cases */
4588/* Like 'make_standard' but errors are deliberately introduced into the calls
4589 * to ensure that they get detected - it should not be possible to write an
4590 * invalid image with libpng!
4591 */
4592/* TODO: the 'set' functions can probably all be made to take a
4593 * png_const_structp rather than a modifiable one.
4594 */
4595#ifdef PNG_WARNINGS_SUPPORTED
4596static void
4597sBIT0_error_fn(png_structp pp, png_infop pi)
4598{
4599 /* 0 is invalid... */
4600 png_color_8 bad;
4601 bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
4602 png_set_sBIT(pp, pi, &bad);
4603}
4604
4605static void
4606sBIT_error_fn(png_structp pp, png_infop pi)
4607{
4608 png_byte bit_depth;
4609 png_color_8 bad;
4610
4611 if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
4612 bit_depth = 8;
4613
4614 else
4615 bit_depth = png_get_bit_depth(pp, pi);
4616
4617 /* Now we know the bit depth we can easily generate an invalid sBIT entry */
4618 bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
4619 (png_byte)(bit_depth+1);
4620 png_set_sBIT(pp, pi, &bad);
4621}
4622
4623static const struct
4624{
4625 void (*fn)(png_structp, png_infop);
4626 const char *msg;
4627 unsigned int warning :1; /* the error is a warning... */
4628} error_test[] =
4629 {
4630 /* no warnings makes these errors undetectable prior to 1.7.0 */
4631 { sBIT0_error_fn, "sBIT(0): failed to detect error",
4632 PNG_LIBPNG_VER < 10700 },
4633
4634 { sBIT_error_fn, "sBIT(too big): failed to detect error",
4635 PNG_LIBPNG_VER < 10700 },
4636 };
4637
4638static void
4639make_error(png_store* const ps, png_byte const colour_type,
4640 png_byte bit_depth, int interlace_type, int test, png_const_charp name)
4641{
4642 context(ps, fault);
4643
4644 check_interlace_type(interlace_type);
4645
4646 Try
4647 {
4648 png_infop pi;
4649 const png_structp pp = set_store_for_write(ps, &pi, name);
4650 png_uint_32 w, h;
4651 gnu_volatile(pp)
4652
4653 if (pp == NULL)
4654 Throw ps;
4655
4656 w = transform_width(pp, colour_type, bit_depth);
4657 gnu_volatile(w)
4658 h = transform_height(pp, colour_type, bit_depth);
4659 gnu_volatile(h)
4660 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4661 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4662
4663 if (colour_type == 3) /* palette */
4664 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4665
4666 /* Time for a few errors; these are in various optional chunks, the
4667 * standard tests test the standard chunks pretty well.
4668 */
4669# define exception__prev exception_prev_1
4670# define exception__env exception_env_1
4671 Try
4672 {
4673 gnu_volatile(exception__prev)
4674
4675 /* Expect this to throw: */
4676 ps->expect_error = !error_test[test].warning;
4677 ps->expect_warning = error_test[test].warning;
4678 ps->saw_warning = 0;
4679 error_test[test].fn(pp, pi);
4680
4681 /* Normally the error is only detected here: */
4682 png_write_info(pp, pi);
4683
4684 /* And handle the case where it was only a warning: */
4685 if (ps->expect_warning && ps->saw_warning)
4686 Throw ps;
4687
4688 /* If we get here there is a problem, we have success - no error or
4689 * no warning - when we shouldn't have success. Log an error.
4690 */
4691 store_log(ps, pp, error_test[test].msg, 1 /*error*/);
4692 }
4693
4694 Catch (fault)
4695 { /* expected exit */
4696 }
4697#undef exception__prev
4698#undef exception__env
4699
4700 /* And clear these flags */
4701 ps->expect_warning = 0;
4702
4703 if (ps->expect_error)
4704 ps->expect_error = 0;
4705
4706 else
4707 {
4708 /* Now write the whole image, just to make sure that the detected, or
4709 * undetected, errro has not created problems inside libpng. This
4710 * doesn't work if there was a png_error in png_write_info because that
4711 * can abort before PLTE was written.
4712 */
4713 if (png_get_rowbytes(pp, pi) !=
4714 transform_rowsize(pp, colour_type, bit_depth))
4715 png_error(pp, "row size incorrect");
4716
4717 else
4718 {
4719 int npasses = set_write_interlace_handling(pp, interlace_type);
4720 int pass;
4721
4722 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4723 png_error(pp, "write: png_set_interlace_handling failed");
4724
4725 for (pass=0; pass<npasses; ++pass)
4726 {
4727 png_uint_32 y;
4728
4729 for (y=0; y<h; ++y)
4730 {
4731 png_byte buffer[TRANSFORM_ROWMAX];
4732
4733 transform_row(pp, buffer, colour_type, bit_depth, y);
4734
4735# if do_own_interlace
4736 /* If do_own_interlace *and* the image is interlaced we
4737 * need a reduced interlace row; this may be reduced to
4738 * empty.
4739 */
4740 if (interlace_type == PNG_INTERLACE_ADAM7)
4741 {
4742 /* The row must not be written if it doesn't exist,
4743 * notice that there are two conditions here, either the
4744 * row isn't ever in the pass or the row would be but
4745 * isn't wide enough to contribute any pixels. In fact
4746 * the wPass test can be used to skip the whole y loop
4747 * in this case.
4748 */
4749 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4750 PNG_PASS_COLS(w, pass) > 0)
4751 interlace_row(buffer, buffer,
4752 bit_size(pp, colour_type, bit_depth), w, pass,
4753 0/*data always bigendian*/);
4754 else
4755 continue;
4756 }
4757# endif /* do_own_interlace */
4758
4759 png_write_row(pp, buffer);
4760 }
4761 }
4762 } /* image writing */
4763
4764 png_write_end(pp, pi);
4765 }
4766
4767 /* The following deletes the file that was just written. */
4768 store_write_reset(ps);
4769 }
4770
4771 Catch(fault)
4772 {
4773 store_write_reset(fault);
4774 }
4775}
4776
4777static int
4778make_errors(png_modifier* const pm, png_byte const colour_type,
4779 int bdlo, int const bdhi)
4780{
4781 for (; bdlo <= bdhi; ++bdlo)
4782 {
4783 int interlace_type;
4784
4785 for (interlace_type = PNG_INTERLACE_NONE;
4786 interlace_type < INTERLACE_LAST; ++interlace_type)
4787 {
4788 unsigned int test;
4789 char name[FILE_NAME_SIZE];
4790
4791 standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
4792 interlace_type, 0, 0, do_own_interlace);
4793
4794 for (test=0; test<ARRAY_SIZE(error_test); ++test)
4795 {
4796 make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
4797 test, name);
4798
4799 if (fail(pm))
4800 return 0;
4801 }
4802 }
4803 }
4804
4805 return 1; /* keep going */
4806}
4807#endif /* PNG_WARNINGS_SUPPORTED */
4808
4809static void
4810perform_error_test(png_modifier *pm)
4811{
4812#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
4813 /* Need to do this here because we just write in this test. */
4814 safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
4815
4816 if (!make_errors(pm, 0, 0, WRITE_BDHI))
4817 return;
4818
4819 if (!make_errors(pm, 2, 3, WRITE_BDHI))
4820 return;
4821
4822 if (!make_errors(pm, 3, 0, 3))
4823 return;
4824
4825 if (!make_errors(pm, 4, 3, WRITE_BDHI))
4826 return;
4827
4828 if (!make_errors(pm, 6, 3, WRITE_BDHI))
4829 return;
4830#else
4831 UNUSED(pm)
4832#endif
4833}
4834
4835/* This is just to validate the internal PNG formatting code - if this fails
4836 * then the warning messages the library outputs will probably be garbage.
4837 */
4838static void
4839perform_formatting_test(png_store *ps)
4840{
4841#ifdef PNG_TIME_RFC1123_SUPPORTED
4842 /* The handle into the formatting code is the RFC1123 support; this test does
4843 * nothing if that is compiled out.
4844 */
4845 context(ps, fault);
4846
4847 Try
4848 {
4849 png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
4850 png_const_charp result;
4851# if PNG_LIBPNG_VER >= 10600
4852 char timestring[29];
4853# endif
4854 png_structp pp;
4855 png_time pt;
4856
4857 pp = set_store_for_write(ps, NULL, "libpng formatting test");
4858
4859 if (pp == NULL)
4860 Throw ps;
4861
4862
4863 /* Arbitrary settings: */
4864 pt.year = 2079;
4865 pt.month = 8;
4866 pt.day = 29;
4867 pt.hour = 13;
4868 pt.minute = 53;
4869 pt.second = 60; /* a leap second */
4870
4871# if PNG_LIBPNG_VER < 10600
4872 result = png_convert_to_rfc1123(pp, &pt);
4873# else
4874 if (png_convert_to_rfc1123_buffer(timestring, &pt))
4875 result = timestring;
4876
4877 else
4878 result = NULL;
4879# endif
4880
4881 if (result == NULL)
4882 png_error(pp, "png_convert_to_rfc1123 failed");
4883
4884 if (strcmp(result, correct) != 0)
4885 {
4886 size_t pos = 0;
4887 char msg[128];
4888
4889 pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
4890 pos = safecat(msg, sizeof msg, pos, correct);
4891 pos = safecat(msg, sizeof msg, pos, ") returned: '");
4892 pos = safecat(msg, sizeof msg, pos, result);
4893 pos = safecat(msg, sizeof msg, pos, "'");
4894
4895 png_error(pp, msg);
4896 }
4897
4898 store_write_reset(ps);
4899 }
4900
4901 Catch(fault)
4902 {
4903 store_write_reset(fault);
4904 }
4905#else
4906 UNUSED(ps)
4907#endif
4908}
4909
4910#ifdef PNG_READ_SUPPORTED
4911/* Because we want to use the same code in both the progressive reader and the
4912 * sequential reader it is necessary to deal with the fact that the progressive
4913 * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
4914 * must contain all the test parameters and all the local variables directly
4915 * accessible to the sequential reader implementation.
4916 *
4917 * The technique adopted is to reinvent part of what Dijkstra termed a
4918 * 'display'; an array of pointers to the stack frames of enclosing functions so
4919 * that a nested function definition can access the local (C auto) variables of
4920 * the functions that contain its definition. In fact C provides the first
4921 * pointer (the local variables - the stack frame pointer) and the last (the
4922 * global variables - the BCPL global vector typically implemented as global
4923 * addresses), this code requires one more pointer to make the display - the
4924 * local variables (and function call parameters) of the function that actually
4925 * invokes either the progressive or sequential reader.
4926 *
4927 * Perhaps confusingly this technique is confounded with classes - the
4928 * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
4929 * A gamma_display is a standard_display, taking advantage of the ANSI-C
4930 * requirement that the pointer to the first member of a structure must be the
4931 * same as the pointer to the structure. This allows us to reuse standard_
4932 * functions in the gamma test code; something that could not be done with
4933 * nested functions!
4934 */
4935typedef struct standard_display
4936{
4937 png_store* ps; /* Test parameters (passed to the function) */
4938 png_byte colour_type;
4939 png_byte bit_depth;
4940 png_byte red_sBIT; /* Input data sBIT values. */
4941 png_byte green_sBIT;
4942 png_byte blue_sBIT;
4943 png_byte alpha_sBIT;
4944 png_byte interlace_type;
4945 png_byte filler; /* Output has a filler */
4946 png_uint_32 id; /* Calculated file ID */
4947 png_uint_32 w; /* Width of image */
4948 png_uint_32 h; /* Height of image */
4949 int npasses; /* Number of interlaced passes */
4950 png_uint_32 pixel_size; /* Width of one pixel in bits */
4951 png_uint_32 bit_width; /* Width of output row in bits */
4952 size_t cbRow; /* Bytes in a row of the output image */
4953 int do_interlace; /* Do interlacing internally */
4954 int littleendian; /* App (row) data is little endian */
4955 int is_transparent; /* Transparency information was present. */
4956 int has_tRNS; /* color type GRAY or RGB with a tRNS chunk. */
4957 int speed; /* Doing a speed test */
4958 int use_update_info;/* Call update_info, not start_image */
4959 struct
4960 {
4961 png_uint_16 red;
4962 png_uint_16 green;
4963 png_uint_16 blue;
4964 } transparent; /* The transparent color, if set. */
4965 int npalette; /* Number of entries in the palette. */
4966 store_palette
4967 palette;
4968} standard_display;
4969
4970static void
4971standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
4972 int do_interlace, int use_update_info)
4973{
4974 memset(dp, 0, sizeof *dp);
4975
4976 dp->ps = ps;
4977 dp->colour_type = COL_FROM_ID(id);
4978 dp->bit_depth = DEPTH_FROM_ID(id);
4979 if (dp->bit_depth < 1 || dp->bit_depth > 16)
4980 internal_error(ps, "internal: bad bit depth");
4981 if (dp->colour_type == 3)
4982 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
4983 else
4984 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
4985 dp->bit_depth;
4986 dp->interlace_type = INTERLACE_FROM_ID(id);
4987 check_interlace_type(dp->interlace_type);
4988 dp->id = id;
4989 /* All the rest are filled in after the read_info: */
4990 dp->w = 0;
4991 dp->h = 0;
4992 dp->npasses = 0;
4993 dp->pixel_size = 0;
4994 dp->bit_width = 0;
4995 dp->cbRow = 0;
4996 dp->do_interlace = do_interlace;
4997 dp->littleendian = 0;
4998 dp->is_transparent = 0;
4999 dp->speed = ps->speed;
5000 dp->use_update_info = use_update_info;
5001 dp->npalette = 0;
5002 /* Preset the transparent color to black: */
5003 memset(&dp->transparent, 0, sizeof dp->transparent);
5004 /* Preset the palette to full intensity/opaque througout: */
5005 memset(dp->palette, 0xff, sizeof dp->palette);
5006}
5007
5008/* Initialize the palette fields - this must be done later because the palette
5009 * comes from the particular png_store_file that is selected.
5010 */
5011static void
5012standard_palette_init(standard_display *dp)
5013{
5014 store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
5015
5016 /* The remaining entries remain white/opaque. */
5017 if (dp->npalette > 0)
5018 {
5019 int i = dp->npalette;
5020 memcpy(dp->palette, palette, i * sizeof *palette);
5021
5022 /* Check for a non-opaque palette entry: */
5023 while (--i >= 0)
5024 if (palette[i].alpha < 255)
5025 break;
5026
5027# ifdef __GNUC__
5028 /* GCC can't handle the more obviously optimizable version. */
5029 if (i >= 0)
5030 dp->is_transparent = 1;
5031 else
5032 dp->is_transparent = 0;
5033# else
5034 dp->is_transparent = (i >= 0);
5035# endif
5036 }
5037}
5038
5039/* Utility to read the palette from the PNG file and convert it into
5040 * store_palette format. This returns 1 if there is any transparency in the
5041 * palette (it does not check for a transparent colour in the non-palette case.)
5042 */
5043static int
5044read_palette(store_palette palette, int *npalette, png_const_structp pp,
5045 png_infop pi)
5046{
5047 png_colorp pal;
5048 png_bytep trans_alpha;
5049 int num;
5050
5051 pal = 0;
5052 *npalette = -1;
5053
5054 if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
5055 {
5056 int i = *npalette;
5057
5058 if (i <= 0 || i > 256)
5059 png_error(pp, "validate: invalid PLTE count");
5060
5061 while (--i >= 0)
5062 {
5063 palette[i].red = pal[i].red;
5064 palette[i].green = pal[i].green;
5065 palette[i].blue = pal[i].blue;
5066 }
5067
5068 /* Mark the remainder of the entries with a flag value (other than
5069 * white/opaque which is the flag value stored above.)
5070 */
5071 memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
5072 }
5073
5074 else /* !png_get_PLTE */
5075 {
5076 if (*npalette != (-1))
5077 png_error(pp, "validate: invalid PLTE result");
5078 /* But there is no palette, so record this: */
5079 *npalette = 0;
5080 memset(palette, 113, sizeof (store_palette));
5081 }
5082
5083 trans_alpha = 0;
5084 num = 2; /* force error below */
5085 if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
5086 (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
5087 /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
5088 * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
5089 * so in the above call we get a success, we get a pointer (who knows what
5090 * to) and we get num_trans == 0:
5091 */
5092 !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
5093 {
5094 int i;
5095
5096 /* Any of these are crash-worthy - given the implementation of
5097 * png_get_tRNS up to 1.5 an app won't crash if it just checks the
5098 * result above and fails to check that the variables it passed have
5099 * actually been filled in! Note that if the app were to pass the
5100 * last, png_color_16p, variable too it couldn't rely on this.
5101 */
5102 if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
5103 png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
5104
5105 for (i=0; i<num; ++i)
5106 palette[i].alpha = trans_alpha[i];
5107
5108 for (num=*npalette; i<num; ++i)
5109 palette[i].alpha = 255;
5110
5111 for (; i<256; ++i)
5112 palette[i].alpha = 33; /* flag value */
5113
5114 return 1; /* transparency */
5115 }
5116
5117 else
5118 {
5119 /* No palette transparency - just set the alpha channel to opaque. */
5120 int i;
5121
5122 for (i=0, num=*npalette; i<num; ++i)
5123 palette[i].alpha = 255;
5124
5125 for (; i<256; ++i)
5126 palette[i].alpha = 55; /* flag value */
5127
5128 return 0; /* no transparency */
5129 }
5130}
5131
5132/* Utility to validate the palette if it should not have changed (the
5133 * non-transform case).
5134 */
5135static void
5136standard_palette_validate(standard_display *dp, png_const_structp pp,
5137 png_infop pi)
5138{
5139 int npalette;
5140 store_palette palette;
5141
5142 if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
5143 png_error(pp, "validate: palette transparency changed");
5144
5145 if (npalette != dp->npalette)
5146 {
5147 size_t pos = 0;
5148 char msg[64];
5149
5150 pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
5151 pos = safecatn(msg, sizeof msg, pos, dp->npalette);
5152 pos = safecat(msg, sizeof msg, pos, " -> ");
5153 pos = safecatn(msg, sizeof msg, pos, npalette);
5154 png_error(pp, msg);
5155 }
5156
5157 {
5158 int i = npalette; /* npalette is aliased */
5159
5160 while (--i >= 0)
5161 if (palette[i].red != dp->palette[i].red ||
5162 palette[i].green != dp->palette[i].green ||
5163 palette[i].blue != dp->palette[i].blue ||
5164 palette[i].alpha != dp->palette[i].alpha)
5165 png_error(pp, "validate: PLTE or tRNS chunk changed");
5166 }
5167}
5168
5169/* By passing a 'standard_display' the progressive callbacks can be used
5170 * directly by the sequential code, the functions suffixed "_imp" are the
5171 * implementations, the functions without the suffix are the callbacks.
5172 *
5173 * The code for the info callback is split into two because this callback calls
5174 * png_read_update_info or png_start_read_image and what gets called depends on
5175 * whether the info needs updating (we want to test both calls in pngvalid.)
5176 */
5177static void
5178standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
5179{
5180 if (png_get_bit_depth(pp, pi) != dp->bit_depth)
5181 png_error(pp, "validate: bit depth changed");
5182
5183 if (png_get_color_type(pp, pi) != dp->colour_type)
5184 png_error(pp, "validate: color type changed");
5185
5186 if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
5187 png_error(pp, "validate: filter type changed");
5188
5189 if (png_get_interlace_type(pp, pi) != dp->interlace_type)
5190 png_error(pp, "validate: interlacing changed");
5191
5192 if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
5193 png_error(pp, "validate: compression type changed");
5194
5195 dp->w = png_get_image_width(pp, pi);
5196
5197 if (dp->w != standard_width(pp, dp->id))
5198 png_error(pp, "validate: image width changed");
5199
5200 dp->h = png_get_image_height(pp, pi);
5201
5202 if (dp->h != standard_height(pp, dp->id))
5203 png_error(pp, "validate: image height changed");
5204
5205 /* Record (but don't check at present) the input sBIT according to the colour
5206 * type information.
5207 */
5208 {
5209 png_color_8p sBIT = 0;
5210
5211 if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
5212 {
5213 int sBIT_invalid = 0;
5214
5215 if (sBIT == 0)
5216 png_error(pp, "validate: unexpected png_get_sBIT result");
5217
5218 if (dp->colour_type & PNG_COLOR_MASK_COLOR)
5219 {
5220 if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
5221 sBIT_invalid = 1;
5222 else
5223 dp->red_sBIT = sBIT->red;
5224
5225 if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
5226 sBIT_invalid = 1;
5227 else
5228 dp->green_sBIT = sBIT->green;
5229
5230 if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
5231 sBIT_invalid = 1;
5232 else
5233 dp->blue_sBIT = sBIT->blue;
5234 }
5235
5236 else /* !COLOR */
5237 {
5238 if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
5239 sBIT_invalid = 1;
5240 else
5241 dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
5242 }
5243
5244 /* All 8 bits in tRNS for a palette image are significant - see the
5245 * spec.
5246 */
5247 if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
5248 {
5249 if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
5250 sBIT_invalid = 1;
5251 else
5252 dp->alpha_sBIT = sBIT->alpha;
5253 }
5254
5255 if (sBIT_invalid)
5256 png_error(pp, "validate: sBIT value out of range");
5257 }
5258 }
5259
5260 /* Important: this is validating the value *before* any transforms have been
5261 * put in place. It doesn't matter for the standard tests, where there are
5262 * no transforms, but it does for other tests where rowbytes may change after
5263 * png_read_update_info.
5264 */
5265 if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
5266 png_error(pp, "validate: row size changed");
5267
5268 /* Validate the colour type 3 palette (this can be present on other color
5269 * types.)
5270 */
5271 standard_palette_validate(dp, pp, pi);
5272
5273 /* In any case always check for a tranparent color (notice that the
5274 * colour type 3 case must not give a successful return on the get_tRNS call
5275 * with these arguments!)
5276 */
5277 {
5278 png_color_16p trans_color = 0;
5279
5280 if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
5281 {
5282 if (trans_color == 0)
5283 png_error(pp, "validate: unexpected png_get_tRNS (color) result");
5284
5285 switch (dp->colour_type)
5286 {
5287 case 0:
5288 dp->transparent.red = dp->transparent.green = dp->transparent.blue =
5289 trans_color->gray;
5290 dp->has_tRNS = 1;
5291 break;
5292
5293 case 2:
5294 dp->transparent.red = trans_color->red;
5295 dp->transparent.green = trans_color->green;
5296 dp->transparent.blue = trans_color->blue;
5297 dp->has_tRNS = 1;
5298 break;
5299
5300 case 3:
5301 /* Not expected because it should result in the array case
5302 * above.
5303 */
5304 png_error(pp, "validate: unexpected png_get_tRNS result");
5305 break;
5306
5307 default:
5308 png_error(pp, "validate: invalid tRNS chunk with alpha image");
5309 }
5310 }
5311 }
5312
5313 /* Read the number of passes - expected to match the value used when
5314 * creating the image (interlaced or not). This has the side effect of
5315 * turning on interlace handling (if do_interlace is not set.)
5316 */
5317 dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
5318 if (!dp->do_interlace)
5319 {
5320# ifdef PNG_READ_INTERLACING_SUPPORTED
5321 if (dp->npasses != png_set_interlace_handling(pp))
5322 png_error(pp, "validate: file changed interlace type");
5323# else /* !READ_INTERLACING */
5324 /* This should never happen: the relevant tests (!do_interlace) should
5325 * not be run.
5326 */
5327 if (dp->npasses > 1)
5328 png_error(pp, "validate: no libpng interlace support");
5329# endif /* !READ_INTERLACING */
5330 }
5331
5332 /* Caller calls png_read_update_info or png_start_read_image now, then calls
5333 * part2.
5334 */
5335}
5336
5337/* This must be called *after* the png_read_update_info call to get the correct
5338 * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
5339 * image.
5340 */
5341static void
5342standard_info_part2(standard_display *dp, png_const_structp pp,
5343 png_const_infop pi, int nImages)
5344{
5345 /* Record cbRow now that it can be found. */
5346 {
5347 png_byte ct = png_get_color_type(pp, pi);
5348 png_byte bd = png_get_bit_depth(pp, pi);
5349
5350 if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) &&
5351 dp->filler)
5352 ct |= 4; /* handle filler as faked alpha channel */
5353
5354 dp->pixel_size = bit_size(pp, ct, bd);
5355 }
5356 dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
5357 dp->cbRow = png_get_rowbytes(pp, pi);
5358
5359 /* Validate the rowbytes here again. */
5360 if (dp->cbRow != (dp->bit_width+7)/8)
5361 png_error(pp, "bad png_get_rowbytes calculation");
5362
5363 /* Then ensure there is enough space for the output image(s). */
5364 store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
5365}
5366
5367static void
5368standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
5369 int nImages)
5370{
5371 /* Note that the validation routine has the side effect of turning on
5372 * interlace handling in the subsequent code.
5373 */
5374 standard_info_part1(dp, pp, pi);
5375
5376 /* And the info callback has to call this (or png_read_update_info - see
5377 * below in the png_modifier code for that variant.
5378 */
5379 if (dp->use_update_info)
5380 {
5381 /* For debugging the effect of multiple calls: */
5382 int i = dp->use_update_info;
5383 while (i-- > 0)
5384 png_read_update_info(pp, pi);
5385 }
5386
5387 else
5388 png_start_read_image(pp);
5389
5390 /* Validate the height, width and rowbytes plus ensure that sufficient buffer
5391 * exists for decoding the image.
5392 */
5393 standard_info_part2(dp, pp, pi, nImages);
5394}
5395
5396static void PNGCBAPI
5397standard_info(png_structp pp, png_infop pi)
5398{
5399 standard_display *dp = voidcast(standard_display*,
5400 png_get_progressive_ptr(pp));
5401
5402 /* Call with nImages==1 because the progressive reader can only produce one
5403 * image.
5404 */
5405 standard_info_imp(dp, pp, pi, 1 /*only one image*/);
5406}
5407
5408static void PNGCBAPI
5409progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
5410{
5411 png_const_structp pp = ppIn;
5412 const standard_display *dp = voidcast(standard_display*,
5413 png_get_progressive_ptr(pp));
5414
5415 /* When handling interlacing some rows will be absent in each pass, the
5416 * callback still gets called, but with a NULL pointer. This is checked
5417 * in the 'else' clause below. We need our own 'cbRow', but we can't call
5418 * png_get_rowbytes because we got no info structure.
5419 */
5420 if (new_row != NULL)
5421 {
5422 png_bytep row;
5423
5424 /* In the case where the reader doesn't do the interlace it gives
5425 * us the y in the sub-image:
5426 */
5427 if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
5428 {
5429#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
5430 /* Use this opportunity to validate the png 'current' APIs: */
5431 if (y != png_get_current_row_number(pp))
5432 png_error(pp, "png_get_current_row_number is broken");
5433
5434 if (pass != png_get_current_pass_number(pp))
5435 png_error(pp, "png_get_current_pass_number is broken");
5436#endif /* USER_TRANSFORM_INFO */
5437
5438 y = PNG_ROW_FROM_PASS_ROW(y, pass);
5439 }
5440
5441 /* Validate this just in case. */
5442 if (y >= dp->h)
5443 png_error(pp, "invalid y to progressive row callback");
5444
5445 row = store_image_row(dp->ps, pp, 0, y);
5446
5447 /* Combine the new row into the old: */
5448#ifdef PNG_READ_INTERLACING_SUPPORTED
5449 if (dp->do_interlace)
5450#endif /* READ_INTERLACING */
5451 {
5452 if (dp->interlace_type == PNG_INTERLACE_ADAM7)
5453 deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass,
5454 dp->littleendian);
5455 else
5456 row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian);
5457 }
5458#ifdef PNG_READ_INTERLACING_SUPPORTED
5459 else
5460 png_progressive_combine_row(pp, row, new_row);
5461#endif /* PNG_READ_INTERLACING_SUPPORTED */
5462 }
5463
5464 else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
5465 PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
5466 PNG_PASS_COLS(dp->w, pass) > 0)
5467 png_error(pp, "missing row in progressive de-interlacing");
5468}
5469
5470static void
5471sequential_row(standard_display *dp, png_structp pp, png_infop pi,
5472 const int iImage, const int iDisplay)
5473{
5474 const int npasses = dp->npasses;
5475 const int do_interlace = dp->do_interlace &&
5476 dp->interlace_type == PNG_INTERLACE_ADAM7;
5477 const png_uint_32 height = standard_height(pp, dp->id);
5478 const png_uint_32 width = standard_width(pp, dp->id);
5479 const png_store* ps = dp->ps;
5480 int pass;
5481
5482 for (pass=0; pass<npasses; ++pass)
5483 {
5484 png_uint_32 y;
5485 png_uint_32 wPass = PNG_PASS_COLS(width, pass);
5486
5487 for (y=0; y<height; ++y)
5488 {
5489 if (do_interlace)
5490 {
5491 /* wPass may be zero or this row may not be in this pass.
5492 * png_read_row must not be called in either case.
5493 */
5494 if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
5495 {
5496 /* Read the row into a pair of temporary buffers, then do the
5497 * merge here into the output rows.
5498 */
5499 png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
5500
5501 /* The following aids (to some extent) error detection - we can
5502 * see where png_read_row wrote. Use opposite values in row and
5503 * display to make this easier. Don't use 0xff (which is used in
5504 * the image write code to fill unused bits) or 0 (which is a
5505 * likely value to overwrite unused bits with).
5506 */
5507 memset(row, 0xc5, sizeof row);
5508 memset(display, 0x5c, sizeof display);
5509
5510 png_read_row(pp, row, display);
5511
5512 if (iImage >= 0)
5513 deinterlace_row(store_image_row(ps, pp, iImage, y), row,
5514 dp->pixel_size, dp->w, pass, dp->littleendian);
5515
5516 if (iDisplay >= 0)
5517 deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
5518 dp->pixel_size, dp->w, pass, dp->littleendian);
5519 }
5520 }
5521 else
5522 png_read_row(pp,
5523 iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
5524 iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
5525 }
5526 }
5527
5528 /* And finish the read operation (only really necessary if the caller wants
5529 * to find additional data in png_info from chunks after the last IDAT.)
5530 */
5531 png_read_end(pp, pi);
5532}
5533
5534#ifdef PNG_TEXT_SUPPORTED
5535static void
5536standard_check_text(png_const_structp pp, png_const_textp tp,
5537 png_const_charp keyword, png_const_charp text)
5538{
5539 char msg[1024];
5540 size_t pos = safecat(msg, sizeof msg, 0, "text: ");
5541 size_t ok;
5542
5543 pos = safecat(msg, sizeof msg, pos, keyword);
5544 pos = safecat(msg, sizeof msg, pos, ": ");
5545 ok = pos;
5546
5547 if (tp->compression != TEXT_COMPRESSION)
5548 {
5549 char buf[64];
5550
5551 sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION,
5552 tp->compression);
5553 pos = safecat(msg, sizeof msg, pos, buf);
5554 }
5555
5556 if (tp->key == NULL || strcmp(tp->key, keyword) != 0)
5557 {
5558 pos = safecat(msg, sizeof msg, pos, "keyword \"");
5559 if (tp->key != NULL)
5560 {
5561 pos = safecat(msg, sizeof msg, pos, tp->key);
5562 pos = safecat(msg, sizeof msg, pos, "\", ");
5563 }
5564
5565 else
5566 pos = safecat(msg, sizeof msg, pos, "null, ");
5567 }
5568
5569 if (tp->text == NULL)
5570 pos = safecat(msg, sizeof msg, pos, "text lost, ");
5571
5572 else
5573 {
5574 if (tp->text_length != strlen(text))
5575 {
5576 char buf[64];
5577 sprintf(buf, "text length changed[%lu->%lu], ",
5578 (unsigned long)strlen(text), (unsigned long)tp->text_length);
5579 pos = safecat(msg, sizeof msg, pos, buf);
5580 }
5581
5582 if (strcmp(tp->text, text) != 0)
5583 {
5584 pos = safecat(msg, sizeof msg, pos, "text becomes \"");
5585 pos = safecat(msg, sizeof msg, pos, tp->text);
5586 pos = safecat(msg, sizeof msg, pos, "\" (was \"");
5587 pos = safecat(msg, sizeof msg, pos, text);
5588 pos = safecat(msg, sizeof msg, pos, "\"), ");
5589 }
5590 }
5591
5592 if (tp->itxt_length != 0)
5593 pos = safecat(msg, sizeof msg, pos, "iTXt length set, ");
5594
5595 if (tp->lang != NULL)
5596 {
5597 pos = safecat(msg, sizeof msg, pos, "iTXt language \"");
5598 pos = safecat(msg, sizeof msg, pos, tp->lang);
5599 pos = safecat(msg, sizeof msg, pos, "\", ");
5600 }
5601
5602 if (tp->lang_key != NULL)
5603 {
5604 pos = safecat(msg, sizeof msg, pos, "iTXt keyword \"");
5605 pos = safecat(msg, sizeof msg, pos, tp->lang_key);
5606 pos = safecat(msg, sizeof msg, pos, "\", ");
5607 }
5608
5609 if (pos > ok)
5610 {
5611 msg[pos-2] = '\0'; /* Remove the ", " at the end */
5612 png_error(pp, msg);
5613 }
5614}
5615
5616static void
5617standard_text_validate(standard_display *dp, png_const_structp pp,
5618 png_infop pi, int check_end)
5619{
5620 png_textp tp = NULL;
5621 png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL);
5622
5623 if (num_text == 2 && tp != NULL)
5624 {
5625 standard_check_text(pp, tp, "image name", dp->ps->current->name);
5626
5627 /* This exists because prior to 1.5.18 the progressive reader left the
5628 * png_struct z_stream unreset at the end of the image, so subsequent
5629 * attempts to use it simply returns Z_STREAM_END.
5630 */
5631 if (check_end)
5632 standard_check_text(pp, tp+1, "end marker", "end");
5633 }
5634
5635 else
5636 {
5637 char msg[64];
5638
5639 sprintf(msg, "expected two text items, got %lu",
5640 (unsigned long)num_text);
5641 png_error(pp, msg);
5642 }
5643}
5644#else
5645# define standard_text_validate(dp,pp,pi,check_end) ((void)0)
5646#endif
5647
5648static void
5649standard_row_validate(standard_display *dp, png_const_structp pp,
5650 int iImage, int iDisplay, png_uint_32 y)
5651{
5652 int where;
5653 png_byte std[STANDARD_ROWMAX];
5654
5655 /* The row must be pre-initialized to the magic number here for the size
5656 * tests to pass:
5657 */
5658 memset(std, 178, sizeof std);
5659 standard_row(pp, std, dp->id, y);
5660
5661 /* At the end both the 'row' and 'display' arrays should end up identical.
5662 * In earlier passes 'row' will be partially filled in, with only the pixels
5663 * that have been read so far, but 'display' will have those pixels
5664 * replicated to fill the unread pixels while reading an interlaced image.
5665 */
5666 if (iImage >= 0 &&
5667 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
5668 dp->bit_width)) != 0)
5669 {
5670 char msg[64];
5671 sprintf(msg, "PNG image row[%lu][%d] changed from %.2x to %.2x",
5672 (unsigned long)y, where-1, std[where-1],
5673 store_image_row(dp->ps, pp, iImage, y)[where-1]);
5674 png_error(pp, msg);
5675 }
5676
5677 if (iDisplay >= 0 &&
5678 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
5679 dp->bit_width)) != 0)
5680 {
5681 char msg[64];
5682 sprintf(msg, "display row[%lu][%d] changed from %.2x to %.2x",
5683 (unsigned long)y, where-1, std[where-1],
5684 store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
5685 png_error(pp, msg);
5686 }
5687}
5688
5689static void
5690standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
5691 int iDisplay)
5692{
5693 png_uint_32 y;
5694
5695 if (iImage >= 0)
5696 store_image_check(dp->ps, pp, iImage);
5697
5698 if (iDisplay >= 0)
5699 store_image_check(dp->ps, pp, iDisplay);
5700
5701 for (y=0; y<dp->h; ++y)
5702 standard_row_validate(dp, pp, iImage, iDisplay, y);
5703
5704 /* This avoids false positives if the validation code is never called! */
5705 dp->ps->validated = 1;
5706}
5707
5708static void PNGCBAPI
5709standard_end(png_structp ppIn, png_infop pi)
5710{
5711 png_const_structp pp = ppIn;
5712 standard_display *dp = voidcast(standard_display*,
5713 png_get_progressive_ptr(pp));
5714
5715 UNUSED(pi)
5716
5717 /* Validate the image - progressive reading only produces one variant for
5718 * interlaced images.
5719 */
5720 standard_text_validate(dp, pp, pi,
5721 PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/);
5722 standard_image_validate(dp, pp, 0, -1);
5723}
5724
5725/* A single test run checking the standard image to ensure it is not damaged. */
5726static void
5727standard_test(png_store* const psIn, png_uint_32 const id,
5728 int do_interlace, int use_update_info)
5729{
5730 standard_display d;
5731 context(psIn, fault);
5732
5733 /* Set up the display (stack frame) variables from the arguments to the
5734 * function and initialize the locals that are filled in later.
5735 */
5736 standard_display_init(&d, psIn, id, do_interlace, use_update_info);
5737
5738 /* Everything is protected by a Try/Catch. The functions called also
5739 * typically have local Try/Catch blocks.
5740 */
5741 Try
5742 {
5743 png_structp pp;
5744 png_infop pi;
5745
5746 /* Get a png_struct for reading the image. This will throw an error if it
5747 * fails, so we don't need to check the result.
5748 */
5749 pp = set_store_for_read(d.ps, &pi, d.id,
5750 d.do_interlace ? (d.ps->progressive ?
5751 "pngvalid progressive deinterlacer" :
5752 "pngvalid sequential deinterlacer") : (d.ps->progressive ?
5753 "progressive reader" : "sequential reader"));
5754
5755 /* Initialize the palette correctly from the png_store_file. */
5756 standard_palette_init(&d);
5757
5758 /* Introduce the correct read function. */
5759 if (d.ps->progressive)
5760 {
5761 png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
5762 standard_end);
5763
5764 /* Now feed data into the reader until we reach the end: */
5765 store_progressive_read(d.ps, pp, pi);
5766 }
5767 else
5768 {
5769 /* Note that this takes the store, not the display. */
5770 png_set_read_fn(pp, d.ps, store_read);
5771
5772 /* Check the header values: */
5773 png_read_info(pp, pi);
5774
5775 /* The code tests both versions of the images that the sequential
5776 * reader can produce.
5777 */
5778 standard_info_imp(&d, pp, pi, 2 /*images*/);
5779
5780 /* Need the total bytes in the image below; we can't get to this point
5781 * unless the PNG file values have been checked against the expected
5782 * values.
5783 */
5784 {
5785 sequential_row(&d, pp, pi, 0, 1);
5786
5787 /* After the last pass loop over the rows again to check that the
5788 * image is correct.
5789 */
5790 if (!d.speed)
5791 {
5792 standard_text_validate(&d, pp, pi, 1/*check_end*/);
5793 standard_image_validate(&d, pp, 0, 1);
5794 }
5795 else
5796 d.ps->validated = 1;
5797 }
5798 }
5799
5800 /* Check for validation. */
5801 if (!d.ps->validated)
5802 png_error(pp, "image read failed silently");
5803
5804 /* Successful completion. */
5805 }
5806
5807 Catch(fault)
5808 d.ps = fault; /* make sure this hasn't been clobbered. */
5809
5810 /* In either case clean up the store. */
5811 store_read_reset(d.ps);
5812}
5813
5814static int
5815test_standard(png_modifier* const pm, png_byte const colour_type,
5816 int bdlo, int const bdhi)
5817{
5818 for (; bdlo <= bdhi; ++bdlo)
5819 {
5820 int interlace_type;
5821
5822 for (interlace_type = PNG_INTERLACE_NONE;
5823 interlace_type < INTERLACE_LAST; ++interlace_type)
5824 {
5825 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5826 interlace_type, 0, 0, 0), do_read_interlace, pm->use_update_info);
5827
5828 if (fail(pm))
5829 return 0;
5830 }
5831 }
5832
5833 return 1; /* keep going */
5834}
5835
5836static void
5837perform_standard_test(png_modifier *pm)
5838{
5839 /* Test each colour type over the valid range of bit depths (expressed as
5840 * log2(bit_depth) in turn, stop as soon as any error is detected.
5841 */
5842 if (!test_standard(pm, 0, 0, READ_BDHI))
5843 return;
5844
5845 if (!test_standard(pm, 2, 3, READ_BDHI))
5846 return;
5847
5848 if (!test_standard(pm, 3, 0, 3))
5849 return;
5850
5851 if (!test_standard(pm, 4, 3, READ_BDHI))
5852 return;
5853
5854 if (!test_standard(pm, 6, 3, READ_BDHI))
5855 return;
5856}
5857
5858
5859/********************************** SIZE TESTS ********************************/
5860static int
5861test_size(png_modifier* const pm, png_byte const colour_type,
5862 int bdlo, int const bdhi)
5863{
5864 /* Run the tests on each combination.
5865 *
5866 * NOTE: on my 32 bit x86 each of the following blocks takes
5867 * a total of 3.5 seconds if done across every combo of bit depth
5868 * width and height. This is a waste of time in practice, hence the
5869 * hinc and winc stuff:
5870 */
5871 static const png_byte hinc[] = {1, 3, 11, 1, 5};
5872 static const png_byte winc[] = {1, 9, 5, 7, 1};
5873 const int save_bdlo = bdlo;
5874
5875 for (; bdlo <= bdhi; ++bdlo)
5876 {
5877 png_uint_32 h, w;
5878
5879 for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
5880 {
5881 /* First test all the 'size' images against the sequential
5882 * reader using libpng to deinterlace (where required.) This
5883 * validates the write side of libpng. There are four possibilities
5884 * to validate.
5885 */
5886 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5887 PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
5888 pm->use_update_info);
5889
5890 if (fail(pm))
5891 return 0;
5892
5893 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5894 PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
5895 pm->use_update_info);
5896
5897 if (fail(pm))
5898 return 0;
5899
5900 /* Now validate the interlaced read side - do_interlace true,
5901 * in the progressive case this does actually make a difference
5902 * to the code used in the non-interlaced case too.
5903 */
5904 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5905 PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
5906 pm->use_update_info);
5907
5908 if (fail(pm))
5909 return 0;
5910
5911# if CAN_WRITE_INTERLACE
5912 /* Validate the pngvalid code itself: */
5913 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5914 PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/,
5915 pm->use_update_info);
5916
5917 if (fail(pm))
5918 return 0;
5919# endif
5920 }
5921 }
5922
5923 /* Now do the tests of libpng interlace handling, after we have made sure
5924 * that the pngvalid version works:
5925 */
5926 for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo)
5927 {
5928 png_uint_32 h, w;
5929
5930 for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
5931 {
5932# ifdef PNG_READ_INTERLACING_SUPPORTED
5933 /* Test with pngvalid generated interlaced images first; we have
5934 * already verify these are ok (unless pngvalid has self-consistent
5935 * read/write errors, which is unlikely), so this detects errors in the
5936 * read side first:
5937 */
5938# if CAN_WRITE_INTERLACE
5939 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5940 PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
5941 pm->use_update_info);
5942
5943 if (fail(pm))
5944 return 0;
5945# endif
5946# endif /* READ_INTERLACING */
5947
5948# ifdef PNG_WRITE_INTERLACING_SUPPORTED
5949 /* Test the libpng write side against the pngvalid read side: */
5950 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5951 PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
5952 pm->use_update_info);
5953
5954 if (fail(pm))
5955 return 0;
5956# endif
5957
5958# ifdef PNG_READ_INTERLACING_SUPPORTED
5959# ifdef PNG_WRITE_INTERLACING_SUPPORTED
5960 /* Test both together: */
5961 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5962 PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
5963 pm->use_update_info);
5964
5965 if (fail(pm))
5966 return 0;
5967# endif
5968# endif /* READ_INTERLACING */
5969 }
5970 }
5971
5972 return 1; /* keep going */
5973}
5974
5975static void
5976perform_size_test(png_modifier *pm)
5977{
5978 /* Test each colour type over the valid range of bit depths (expressed as
5979 * log2(bit_depth) in turn, stop as soon as any error is detected.
5980 */
5981 if (!test_size(pm, 0, 0, READ_BDHI))
5982 return;
5983
5984 if (!test_size(pm, 2, 3, READ_BDHI))
5985 return;
5986
5987 /* For the moment don't do the palette test - it's a waste of time when
5988 * compared to the grayscale test.
5989 */
5990#if 0
5991 if (!test_size(pm, 3, 0, 3))
5992 return;
5993#endif
5994
5995 if (!test_size(pm, 4, 3, READ_BDHI))
5996 return;
5997
5998 if (!test_size(pm, 6, 3, READ_BDHI))
5999 return;
6000}
6001
6002
6003/******************************* TRANSFORM TESTS ******************************/
6004#ifdef PNG_READ_TRANSFORMS_SUPPORTED
6005/* A set of tests to validate libpng image transforms. The possibilities here
6006 * are legion because the transforms can be combined in a combinatorial
6007 * fashion. To deal with this some measure of restraint is required, otherwise
6008 * the tests would take forever.
6009 */
6010typedef struct image_pixel
6011{
6012 /* A local (pngvalid) representation of a PNG pixel, in all its
6013 * various forms.
6014 */
6015 unsigned int red, green, blue, alpha; /* For non-palette images. */
6016 unsigned int palette_index; /* For a palette image. */
6017 png_byte colour_type; /* As in the spec. */
6018 png_byte bit_depth; /* Defines bit size in row */
6019 png_byte sample_depth; /* Scale of samples */
6020 unsigned int have_tRNS :1; /* tRNS chunk may need processing */
6021 unsigned int swap_rgb :1; /* RGB swapped to BGR */
6022 unsigned int alpha_first :1; /* Alpha at start, not end */
6023 unsigned int alpha_inverted :1; /* Alpha channel inverted */
6024 unsigned int mono_inverted :1; /* Gray channel inverted */
6025 unsigned int swap16 :1; /* Byte swap 16-bit components */
6026 unsigned int littleendian :1; /* High bits on right */
6027 unsigned int sig_bits :1; /* Pixel shifted (sig bits only) */
6028
6029 /* For checking the code calculates double precision floating point values
6030 * along with an error value, accumulated from the transforms. Because an
6031 * sBIT setting allows larger error bounds (indeed, by the spec, apparently
6032 * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
6033 * channel is stored. This sBIT value is folded in to the stored error value
6034 * at the end of the application of the transforms to the pixel.
6035 *
6036 * If sig_bits is set above the red, green, blue and alpha values have been
6037 * scaled so they only contain the significant bits of the component values.
6038 */
6039 double redf, greenf, bluef, alphaf;
6040 double rede, greene, bluee, alphae;
6041 png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
6042} image_pixel;
6043
6044/* Shared utility function, see below. */
6045static void
6046image_pixel_setf(image_pixel *this, unsigned int rMax, unsigned int gMax,
6047 unsigned int bMax, unsigned int aMax)
6048{
6049 this->redf = this->red / (double)rMax;
6050 this->greenf = this->green / (double)gMax;
6051 this->bluef = this->blue / (double)bMax;
6052 this->alphaf = this->alpha / (double)aMax;
6053
6054 if (this->red < rMax)
6055 this->rede = this->redf * DBL_EPSILON;
6056 else
6057 this->rede = 0;
6058 if (this->green < gMax)
6059 this->greene = this->greenf * DBL_EPSILON;
6060 else
6061 this->greene = 0;
6062 if (this->blue < bMax)
6063 this->bluee = this->bluef * DBL_EPSILON;
6064 else
6065 this->bluee = 0;
6066 if (this->alpha < aMax)
6067 this->alphae = this->alphaf * DBL_EPSILON;
6068 else
6069 this->alphae = 0;
6070}
6071
6072/* Initialize the structure for the next pixel - call this before doing any
6073 * transforms and call it for each pixel since all the fields may need to be
6074 * reset.
6075 */
6076static void
6077image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
6078 png_byte bit_depth, png_uint_32 x, store_palette palette,
6079 const image_pixel *format /*from pngvalid transform of input*/)
6080{
6081 const png_byte sample_depth = (png_byte)(colour_type ==
6082 PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
6083 const unsigned int max = (1U<<sample_depth)-1;
6084 const int swap16 = (format != 0 && format->swap16);
6085 const int littleendian = (format != 0 && format->littleendian);
6086 const int sig_bits = (format != 0 && format->sig_bits);
6087
6088 /* Initially just set everything to the same number and the alpha to opaque.
6089 * Note that this currently assumes a simple palette where entry x has colour
6090 * rgb(x,x,x)!
6091 */
6092 this->palette_index = this->red = this->green = this->blue =
6093 sample(row, colour_type, bit_depth, x, 0, swap16, littleendian);
6094 this->alpha = max;
6095 this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
6096 sample_depth;
6097
6098 /* Then override as appropriate: */
6099 if (colour_type == 3) /* palette */
6100 {
6101 /* This permits the caller to default to the sample value. */
6102 if (palette != 0)
6103 {
6104 const unsigned int i = this->palette_index;
6105
6106 this->red = palette[i].red;
6107 this->green = palette[i].green;
6108 this->blue = palette[i].blue;
6109 this->alpha = palette[i].alpha;
6110 }
6111 }
6112
6113 else /* not palette */
6114 {
6115 unsigned int i = 0;
6116
6117 if ((colour_type & 4) != 0 && format != 0 && format->alpha_first)
6118 {
6119 this->alpha = this->red;
6120 /* This handles the gray case for 'AG' pixels */
6121 this->palette_index = this->red = this->green = this->blue =
6122 sample(row, colour_type, bit_depth, x, 1, swap16, littleendian);
6123 i = 1;
6124 }
6125
6126 if (colour_type & 2)
6127 {
6128 /* Green is second for both BGR and RGB: */
6129 this->green = sample(row, colour_type, bit_depth, x, ++i, swap16,
6130 littleendian);
6131
6132 if (format != 0 && format->swap_rgb) /* BGR */
6133 this->red = sample(row, colour_type, bit_depth, x, ++i, swap16,
6134 littleendian);
6135 else
6136 this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16,
6137 littleendian);
6138 }
6139
6140 else /* grayscale */ if (format != 0 && format->mono_inverted)
6141 this->red = this->green = this->blue = this->red ^ max;
6142
6143 if ((colour_type & 4) != 0) /* alpha */
6144 {
6145 if (format == 0 || !format->alpha_first)
6146 this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16,
6147 littleendian);
6148
6149 if (format != 0 && format->alpha_inverted)
6150 this->alpha ^= max;
6151 }
6152 }
6153
6154 /* Calculate the scaled values, these are simply the values divided by
6155 * 'max' and the error is initialized to the double precision epsilon value
6156 * from the header file.
6157 */
6158 image_pixel_setf(this,
6159 sig_bits ? (1U << format->red_sBIT)-1 : max,
6160 sig_bits ? (1U << format->green_sBIT)-1 : max,
6161 sig_bits ? (1U << format->blue_sBIT)-1 : max,
6162 sig_bits ? (1U << format->alpha_sBIT)-1 : max);
6163
6164 /* Store the input information for use in the transforms - these will
6165 * modify the information.
6166 */
6167 this->colour_type = colour_type;
6168 this->bit_depth = bit_depth;
6169 this->sample_depth = sample_depth;
6170 this->have_tRNS = 0;
6171 this->swap_rgb = 0;
6172 this->alpha_first = 0;
6173 this->alpha_inverted = 0;
6174 this->mono_inverted = 0;
6175 this->swap16 = 0;
6176 this->littleendian = 0;
6177 this->sig_bits = 0;
6178}
6179
6180#if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\
6181 || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\
6182 || defined PNG_READ_BACKGROUND_SUPPORTED
6183/* Convert a palette image to an rgb image. This necessarily converts the tRNS
6184 * chunk at the same time, because the tRNS will be in palette form. The way
6185 * palette validation works means that the original palette is never updated,
6186 * instead the image_pixel value from the row contains the RGB of the
6187 * corresponding palette entry and *this* is updated. Consequently this routine
6188 * only needs to change the colour type information.
6189 */
6190static void
6191image_pixel_convert_PLTE(image_pixel *this)
6192{
6193 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6194 {
6195 if (this->have_tRNS)
6196 {
6197 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6198 this->have_tRNS = 0;
6199 }
6200 else
6201 this->colour_type = PNG_COLOR_TYPE_RGB;
6202
6203 /* The bit depth of the row changes at this point too (notice that this is
6204 * the row format, not the sample depth, which is separate.)
6205 */
6206 this->bit_depth = 8;
6207 }
6208}
6209
6210/* Add an alpha channel; this will import the tRNS information because tRNS is
6211 * not valid in an alpha image. The bit depth will invariably be set to at
6212 * least 8 prior to 1.7.0. Palette images will be converted to alpha (using
6213 * the above API). With png_set_background the alpha channel is never expanded
6214 * but this routine is used by pngvalid to simplify code; 'for_background'
6215 * records this.
6216 */
6217static void
6218image_pixel_add_alpha(image_pixel *this, const standard_display *display,
6219 int for_background)
6220{
6221 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6222 image_pixel_convert_PLTE(this);
6223
6224 if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
6225 {
6226 if (this->colour_type == PNG_COLOR_TYPE_GRAY)
6227 {
6228# if PNG_LIBPNG_VER < 10700
6229 if (!for_background && this->bit_depth < 8)
6230 this->bit_depth = this->sample_depth = 8;
6231# endif
6232
6233 if (this->have_tRNS)
6234 {
6235 /* After 1.7 the expansion of bit depth only happens if there is a
6236 * tRNS chunk to expand at this point.
6237 */
6238# if PNG_LIBPNG_VER >= 10700
6239 if (!for_background && this->bit_depth < 8)
6240 this->bit_depth = this->sample_depth = 8;
6241# endif
6242
6243 this->have_tRNS = 0;
6244
6245 /* Check the input, original, channel value here against the
6246 * original tRNS gray chunk valie.
6247 */
6248 if (this->red == display->transparent.red)
6249 this->alphaf = 0;
6250 else
6251 this->alphaf = 1;
6252 }
6253 else
6254 this->alphaf = 1;
6255
6256 this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
6257 }
6258
6259 else if (this->colour_type == PNG_COLOR_TYPE_RGB)
6260 {
6261 if (this->have_tRNS)
6262 {
6263 this->have_tRNS = 0;
6264
6265 /* Again, check the exact input values, not the current transformed
6266 * value!
6267 */
6268 if (this->red == display->transparent.red &&
6269 this->green == display->transparent.green &&
6270 this->blue == display->transparent.blue)
6271 this->alphaf = 0;
6272 else
6273 this->alphaf = 1;
6274 }
6275 else
6276 this->alphaf = 1;
6277
6278 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6279 }
6280
6281 /* The error in the alpha is zero and the sBIT value comes from the
6282 * original sBIT data (actually it will always be the original bit depth).
6283 */
6284 this->alphae = 0;
6285 this->alpha_sBIT = display->alpha_sBIT;
6286 }
6287}
6288#endif /* transforms that need image_pixel_add_alpha */
6289
6290struct transform_display;
6291typedef struct image_transform
6292{
6293 /* The name of this transform: a string. */
6294 const char *name;
6295
6296 /* Each transform can be disabled from the command line: */
6297 int enable;
6298
6299 /* The global list of transforms; read only. */
6300 struct image_transform *const list;
6301
6302 /* The global count of the number of times this transform has been set on an
6303 * image.
6304 */
6305 unsigned int global_use;
6306
6307 /* The local count of the number of times this transform has been set. */
6308 unsigned int local_use;
6309
6310 /* The next transform in the list, each transform must call its own next
6311 * transform after it has processed the pixel successfully.
6312 */
6313 const struct image_transform *next;
6314
6315 /* A single transform for the image, expressed as a series of function
6316 * callbacks and some space for values.
6317 *
6318 * First a callback to add any required modifications to the png_modifier;
6319 * this gets called just before the modifier is set up for read.
6320 */
6321 void (*ini)(const struct image_transform *this,
6322 struct transform_display *that);
6323
6324 /* And a callback to set the transform on the current png_read_struct:
6325 */
6326 void (*set)(const struct image_transform *this,
6327 struct transform_display *that, png_structp pp, png_infop pi);
6328
6329 /* Then a transform that takes an input pixel in one PNG format or another
6330 * and modifies it by a pngvalid implementation of the transform (thus
6331 * duplicating the libpng intent without, we hope, duplicating the bugs
6332 * in the libpng implementation!) The png_structp is solely to allow error
6333 * reporting via png_error and png_warning.
6334 */
6335 void (*mod)(const struct image_transform *this, image_pixel *that,
6336 png_const_structp pp, const struct transform_display *display);
6337
6338 /* Add this transform to the list and return true if the transform is
6339 * meaningful for this colour type and bit depth - if false then the
6340 * transform should have no effect on the image so there's not a lot of
6341 * point running it.
6342 */
6343 int (*add)(struct image_transform *this,
6344 const struct image_transform **that, png_byte colour_type,
6345 png_byte bit_depth);
6346} image_transform;
6347
6348typedef struct transform_display
6349{
6350 standard_display this;
6351
6352 /* Parameters */
6353 png_modifier* pm;
6354 const image_transform* transform_list;
6355 unsigned int max_gamma_8;
6356
6357 /* Local variables */
6358 png_byte output_colour_type;
6359 png_byte output_bit_depth;
6360 png_byte unpacked;
6361
6362 /* Modifications (not necessarily used.) */
6363 gama_modification gama_mod;
6364 chrm_modification chrm_mod;
6365 srgb_modification srgb_mod;
6366} transform_display;
6367
6368/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
6369static void
6370transform_set_encoding(transform_display *this)
6371{
6372 /* Set up the png_modifier '_current' fields then use these to determine how
6373 * to add appropriate chunks.
6374 */
6375 png_modifier *pm = this->pm;
6376
6377 modifier_set_encoding(pm);
6378
6379 if (modifier_color_encoding_is_set(pm))
6380 {
6381 if (modifier_color_encoding_is_sRGB(pm))
6382 srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
6383
6384 else
6385 {
6386 /* Set gAMA and cHRM separately. */
6387 gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
6388
6389 if (pm->current_encoding != 0)
6390 chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
6391 }
6392 }
6393}
6394
6395/* Three functions to end the list: */
6396static void
6397image_transform_ini_end(const image_transform *this,
6398 transform_display *that)
6399{
6400 UNUSED(this)
6401 UNUSED(that)
6402}
6403
6404static void
6405image_transform_set_end(const image_transform *this,
6406 transform_display *that, png_structp pp, png_infop pi)
6407{
6408 UNUSED(this)
6409 UNUSED(that)
6410 UNUSED(pp)
6411 UNUSED(pi)
6412}
6413
6414/* At the end of the list recalculate the output image pixel value from the
6415 * double precision values set up by the preceding 'mod' calls:
6416 */
6417static unsigned int
6418sample_scale(double sample_value, unsigned int scale)
6419{
6420 sample_value = floor(sample_value * scale + .5);
6421
6422 /* Return NaN as 0: */
6423 if (!(sample_value > 0))
6424 sample_value = 0;
6425 else if (sample_value > scale)
6426 sample_value = scale;
6427
6428 return (unsigned int)sample_value;
6429}
6430
6431static void
6432image_transform_mod_end(const image_transform *this, image_pixel *that,
6433 png_const_structp pp, const transform_display *display)
6434{
6435 const unsigned int scale = (1U<<that->sample_depth)-1;
6436 const int sig_bits = that->sig_bits;
6437
6438 UNUSED(this)
6439 UNUSED(pp)
6440 UNUSED(display)
6441
6442 /* At the end recalculate the digitized red green and blue values according
6443 * to the current sample_depth of the pixel.
6444 *
6445 * The sample value is simply scaled to the maximum, checking for over
6446 * and underflow (which can both happen for some image transforms,
6447 * including simple size scaling, though libpng doesn't do that at present.
6448 */
6449 that->red = sample_scale(that->redf, scale);
6450
6451 /* This is a bit bogus; really the above calculation should use the red_sBIT
6452 * value, not sample_depth, but because libpng does png_set_shift by just
6453 * shifting the bits we get errors if we don't do it the same way.
6454 */
6455 if (sig_bits && that->red_sBIT < that->sample_depth)
6456 that->red >>= that->sample_depth - that->red_sBIT;
6457
6458 /* The error value is increased, at the end, according to the lowest sBIT
6459 * value seen. Common sense tells us that the intermediate integer
6460 * representations are no more accurate than +/- 0.5 in the integral values,
6461 * the sBIT allows the implementation to be worse than this. In addition the
6462 * PNG specification actually permits any error within the range (-1..+1),
6463 * but that is ignored here. Instead the final digitized value is compared,
6464 * below to the digitized value of the error limits - this has the net effect
6465 * of allowing (almost) +/-1 in the output value. It's difficult to see how
6466 * any algorithm that digitizes intermediate results can be more accurate.
6467 */
6468 that->rede += 1./(2*((1U<<that->red_sBIT)-1));
6469
6470 if (that->colour_type & PNG_COLOR_MASK_COLOR)
6471 {
6472 that->green = sample_scale(that->greenf, scale);
6473 if (sig_bits && that->green_sBIT < that->sample_depth)
6474 that->green >>= that->sample_depth - that->green_sBIT;
6475
6476 that->blue = sample_scale(that->bluef, scale);
6477 if (sig_bits && that->blue_sBIT < that->sample_depth)
6478 that->blue >>= that->sample_depth - that->blue_sBIT;
6479
6480 that->greene += 1./(2*((1U<<that->green_sBIT)-1));
6481 that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
6482 }
6483 else
6484 {
6485 that->blue = that->green = that->red;
6486 that->bluef = that->greenf = that->redf;
6487 that->bluee = that->greene = that->rede;
6488 }
6489
6490 if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
6491 that->colour_type == PNG_COLOR_TYPE_PALETTE)
6492 {
6493 that->alpha = sample_scale(that->alphaf, scale);
6494 that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
6495 }
6496 else
6497 {
6498 that->alpha = scale; /* opaque */
6499 that->alphaf = 1; /* Override this. */
6500 that->alphae = 0; /* It's exact ;-) */
6501 }
6502
6503 if (sig_bits && that->alpha_sBIT < that->sample_depth)
6504 that->alpha >>= that->sample_depth - that->alpha_sBIT;
6505}
6506
6507/* Static 'end' structure: */
6508static image_transform image_transform_end =
6509{
6510 "(end)", /* name */
6511 1, /* enable */
6512 0, /* list */
6513 0, /* global_use */
6514 0, /* local_use */
6515 0, /* next */
6516 image_transform_ini_end,
6517 image_transform_set_end,
6518 image_transform_mod_end,
6519 0 /* never called, I want it to crash if it is! */
6520};
6521
6522/* Reader callbacks and implementations, where they differ from the standard
6523 * ones.
6524 */
6525static void
6526transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
6527 const image_transform *transform_list)
6528{
6529 memset(dp, 0, sizeof *dp);
6530
6531 /* Standard fields */
6532 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
6533 pm->use_update_info);
6534
6535 /* Parameter fields */
6536 dp->pm = pm;
6537 dp->transform_list = transform_list;
6538 dp->max_gamma_8 = 16;
6539
6540 /* Local variable fields */
6541 dp->output_colour_type = 255; /* invalid */
6542 dp->output_bit_depth = 255; /* invalid */
6543 dp->unpacked = 0; /* not unpacked */
6544}
6545
6546static void
6547transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
6548{
6549 /* Reuse the standard stuff as appropriate. */
6550 standard_info_part1(&dp->this, pp, pi);
6551
6552 /* Now set the list of transforms. */
6553 dp->transform_list->set(dp->transform_list, dp, pp, pi);
6554
6555 /* Update the info structure for these transforms: */
6556 {
6557 int i = dp->this.use_update_info;
6558 /* Always do one call, even if use_update_info is 0. */
6559 do
6560 png_read_update_info(pp, pi);
6561 while (--i > 0);
6562 }
6563
6564 /* And get the output information into the standard_display */
6565 standard_info_part2(&dp->this, pp, pi, 1/*images*/);
6566
6567 /* Plus the extra stuff we need for the transform tests: */
6568 dp->output_colour_type = png_get_color_type(pp, pi);
6569 dp->output_bit_depth = png_get_bit_depth(pp, pi);
6570
6571 /* If png_set_filler is in action then fake the output color type to include
6572 * an alpha channel where appropriate.
6573 */
6574 if (dp->output_bit_depth >= 8 &&
6575 (dp->output_colour_type == PNG_COLOR_TYPE_RGB ||
6576 dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler)
6577 dp->output_colour_type |= 4;
6578
6579 /* Validate the combination of colour type and bit depth that we are getting
6580 * out of libpng; the semantics of something not in the PNG spec are, at
6581 * best, unclear.
6582 */
6583 switch (dp->output_colour_type)
6584 {
6585 case PNG_COLOR_TYPE_PALETTE:
6586 if (dp->output_bit_depth > 8) goto error;
6587 /* FALLTHROUGH */
6588 case PNG_COLOR_TYPE_GRAY:
6589 if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
6590 dp->output_bit_depth == 4)
6591 break;
6592 /* FALLTHROUGH */
6593 default:
6594 if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
6595 break;
6596 /* FALLTHROUGH */
6597 error:
6598 {
6599 char message[128];
6600 size_t pos;
6601
6602 pos = safecat(message, sizeof message, 0,
6603 "invalid final bit depth: colour type(");
6604 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6605 pos = safecat(message, sizeof message, pos, ") with bit depth: ");
6606 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6607
6608 png_error(pp, message);
6609 }
6610 }
6611
6612 /* Use a test pixel to check that the output agrees with what we expect -
6613 * this avoids running the whole test if the output is unexpected. This also
6614 * checks for internal errors.
6615 */
6616 {
6617 image_pixel test_pixel;
6618
6619 memset(&test_pixel, 0, sizeof test_pixel);
6620 test_pixel.colour_type = dp->this.colour_type; /* input */
6621 test_pixel.bit_depth = dp->this.bit_depth;
6622 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
6623 test_pixel.sample_depth = 8;
6624 else
6625 test_pixel.sample_depth = test_pixel.bit_depth;
6626 /* Don't need sBIT here, but it must be set to non-zero to avoid
6627 * arithmetic overflows.
6628 */
6629 test_pixel.have_tRNS = dp->this.is_transparent != 0;
6630 test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
6631 test_pixel.alpha_sBIT = test_pixel.sample_depth;
6632
6633 dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
6634
6635 if (test_pixel.colour_type != dp->output_colour_type)
6636 {
6637 char message[128];
6638 size_t pos = safecat(message, sizeof message, 0, "colour type ");
6639
6640 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6641 pos = safecat(message, sizeof message, pos, " expected ");
6642 pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
6643
6644 png_error(pp, message);
6645 }
6646
6647 if (test_pixel.bit_depth != dp->output_bit_depth)
6648 {
6649 char message[128];
6650 size_t pos = safecat(message, sizeof message, 0, "bit depth ");
6651
6652 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6653 pos = safecat(message, sizeof message, pos, " expected ");
6654 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6655
6656 png_error(pp, message);
6657 }
6658
6659 /* If both bit depth and colour type are correct check the sample depth.
6660 */
6661 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE &&
6662 test_pixel.sample_depth != 8) /* oops - internal error! */
6663 png_error(pp, "pngvalid: internal: palette sample depth not 8");
6664 else if (dp->unpacked && test_pixel.bit_depth != 8)
6665 png_error(pp, "pngvalid: internal: bad unpacked pixel depth");
6666 else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE
6667 && test_pixel.bit_depth != test_pixel.sample_depth)
6668 {
6669 char message[128];
6670 size_t pos = safecat(message, sizeof message, 0,
6671 "internal: sample depth ");
6672
6673 /* Because unless something has set 'unpacked' or the image is palette
6674 * mapped we expect the transform to keep sample depth and bit depth
6675 * the same.
6676 */
6677 pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
6678 pos = safecat(message, sizeof message, pos, " expected ");
6679 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6680
6681 png_error(pp, message);
6682 }
6683 else if (test_pixel.bit_depth != dp->output_bit_depth)
6684 {
6685 /* This could be a libpng error too; libpng has not produced what we
6686 * expect for the output bit depth.
6687 */
6688 char message[128];
6689 size_t pos = safecat(message, sizeof message, 0,
6690 "internal: bit depth ");
6691
6692 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6693 pos = safecat(message, sizeof message, pos, " expected ");
6694 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6695
6696 png_error(pp, message);
6697 }
6698 }
6699}
6700
6701static void PNGCBAPI
6702transform_info(png_structp pp, png_infop pi)
6703{
6704 transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
6705 pp, pi);
6706}
6707
6708static void
6709transform_range_check(png_const_structp pp, unsigned int r, unsigned int g,
6710 unsigned int b, unsigned int a, unsigned int in_digitized, double in,
6711 unsigned int out, png_byte sample_depth, double err, double limit,
6712 const char *name, double digitization_error)
6713{
6714 /* Compare the scaled, digitzed, values of our local calculation (in+-err)
6715 * with the digitized values libpng produced; 'sample_depth' is the actual
6716 * digitization depth of the libpng output colors (the bit depth except for
6717 * palette images where it is always 8.) The check on 'err' is to detect
6718 * internal errors in pngvalid itself.
6719 */
6720 unsigned int max = (1U<<sample_depth)-1;
6721 double in_min = ceil((in-err)*max - digitization_error);
6722 double in_max = floor((in+err)*max + digitization_error);
6723 if (debugonly(err > limit ||) !(out >= in_min && out <= in_max))
6724 {
6725 char message[256];
6726 size_t pos;
6727
6728 pos = safecat(message, sizeof message, 0, name);
6729 pos = safecat(message, sizeof message, pos, " output value error: rgba(");
6730 pos = safecatn(message, sizeof message, pos, r);
6731 pos = safecat(message, sizeof message, pos, ",");
6732 pos = safecatn(message, sizeof message, pos, g);
6733 pos = safecat(message, sizeof message, pos, ",");
6734 pos = safecatn(message, sizeof message, pos, b);
6735 pos = safecat(message, sizeof message, pos, ",");
6736 pos = safecatn(message, sizeof message, pos, a);
6737 pos = safecat(message, sizeof message, pos, "): ");
6738 pos = safecatn(message, sizeof message, pos, out);
6739 pos = safecat(message, sizeof message, pos, " expected: ");
6740 pos = safecatn(message, sizeof message, pos, in_digitized);
6741 pos = safecat(message, sizeof message, pos, " (");
6742 pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
6743 pos = safecat(message, sizeof message, pos, "..");
6744 pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
6745 pos = safecat(message, sizeof message, pos, ")");
6746
6747 png_error(pp, message);
6748 }
6749
6750 UNUSED(limit)
6751}
6752
6753static void
6754transform_image_validate(transform_display *dp, png_const_structp pp,
6755 png_infop pi)
6756{
6757 /* Constants for the loop below: */
6758 const png_store* const ps = dp->this.ps;
6759 const png_byte in_ct = dp->this.colour_type;
6760 const png_byte in_bd = dp->this.bit_depth;
6761 const png_uint_32 w = dp->this.w;
6762 const png_uint_32 h = dp->this.h;
6763 const png_byte out_ct = dp->output_colour_type;
6764 const png_byte out_bd = dp->output_bit_depth;
6765 const png_byte sample_depth = (png_byte)(out_ct ==
6766 PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
6767 const png_byte red_sBIT = dp->this.red_sBIT;
6768 const png_byte green_sBIT = dp->this.green_sBIT;
6769 const png_byte blue_sBIT = dp->this.blue_sBIT;
6770 const png_byte alpha_sBIT = dp->this.alpha_sBIT;
6771 const int have_tRNS = dp->this.is_transparent;
6772 double digitization_error;
6773
6774 store_palette out_palette;
6775 png_uint_32 y;
6776
6777 UNUSED(pi)
6778
6779 /* Check for row overwrite errors */
6780 store_image_check(dp->this.ps, pp, 0);
6781
6782 /* Read the palette corresponding to the output if the output colour type
6783 * indicates a palette, othewise set out_palette to garbage.
6784 */
6785 if (out_ct == PNG_COLOR_TYPE_PALETTE)
6786 {
6787 /* Validate that the palette count itself has not changed - this is not
6788 * expected.
6789 */
6790 int npalette = (-1);
6791
6792 (void)read_palette(out_palette, &npalette, pp, pi);
6793 if (npalette != dp->this.npalette)
6794 png_error(pp, "unexpected change in palette size");
6795
6796 digitization_error = .5;
6797 }
6798 else
6799 {
6800 png_byte in_sample_depth;
6801
6802 memset(out_palette, 0x5e, sizeof out_palette);
6803
6804 /* use-input-precision means assume that if the input has 8 bit (or less)
6805 * samples and the output has 16 bit samples the calculations will be done
6806 * with 8 bit precision, not 16.
6807 */
6808 if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
6809 in_sample_depth = 8;
6810 else
6811 in_sample_depth = in_bd;
6812
6813 if (sample_depth != 16 || in_sample_depth > 8 ||
6814 !dp->pm->calculations_use_input_precision)
6815 digitization_error = .5;
6816
6817 /* Else calculations are at 8 bit precision, and the output actually
6818 * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits:
6819 */
6820 else
6821 digitization_error = .5 * 257;
6822 }
6823
6824 for (y=0; y<h; ++y)
6825 {
6826 png_const_bytep const pRow = store_image_row(ps, pp, 0, y);
6827 png_uint_32 x;
6828
6829 /* The original, standard, row pre-transforms. */
6830 png_byte std[STANDARD_ROWMAX];
6831
6832 transform_row(pp, std, in_ct, in_bd, y);
6833
6834 /* Go through each original pixel transforming it and comparing with what
6835 * libpng did to the same pixel.
6836 */
6837 for (x=0; x<w; ++x)
6838 {
6839 image_pixel in_pixel, out_pixel;
6840 unsigned int r, g, b, a;
6841
6842 /* Find out what we think the pixel should be: */
6843 image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette,
6844 NULL);
6845
6846 in_pixel.red_sBIT = red_sBIT;
6847 in_pixel.green_sBIT = green_sBIT;
6848 in_pixel.blue_sBIT = blue_sBIT;
6849 in_pixel.alpha_sBIT = alpha_sBIT;
6850 in_pixel.have_tRNS = have_tRNS != 0;
6851
6852 /* For error detection, below. */
6853 r = in_pixel.red;
6854 g = in_pixel.green;
6855 b = in_pixel.blue;
6856 a = in_pixel.alpha;
6857
6858 /* This applies the transforms to the input data, including output
6859 * format operations which must be used when reading the output
6860 * pixel that libpng produces.
6861 */
6862 dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
6863
6864 /* Read the output pixel and compare it to what we got, we don't
6865 * use the error field here, so no need to update sBIT. in_pixel
6866 * says whether we expect libpng to change the output format.
6867 */
6868 image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette,
6869 &in_pixel);
6870
6871 /* We don't expect changes to the index here even if the bit depth is
6872 * changed.
6873 */
6874 if (in_ct == PNG_COLOR_TYPE_PALETTE &&
6875 out_ct == PNG_COLOR_TYPE_PALETTE)
6876 {
6877 if (in_pixel.palette_index != out_pixel.palette_index)
6878 png_error(pp, "unexpected transformed palette index");
6879 }
6880
6881 /* Check the colours for palette images too - in fact the palette could
6882 * be separately verified itself in most cases.
6883 */
6884 if (in_pixel.red != out_pixel.red)
6885 transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
6886 out_pixel.red, sample_depth, in_pixel.rede,
6887 dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
6888 digitization_error);
6889
6890 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6891 in_pixel.green != out_pixel.green)
6892 transform_range_check(pp, r, g, b, a, in_pixel.green,
6893 in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
6894 dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
6895 digitization_error);
6896
6897 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6898 in_pixel.blue != out_pixel.blue)
6899 transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
6900 out_pixel.blue, sample_depth, in_pixel.bluee,
6901 dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
6902 digitization_error);
6903
6904 if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
6905 in_pixel.alpha != out_pixel.alpha)
6906 transform_range_check(pp, r, g, b, a, in_pixel.alpha,
6907 in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
6908 dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
6909 digitization_error);
6910 } /* pixel (x) loop */
6911 } /* row (y) loop */
6912
6913 /* Record that something was actually checked to avoid a false positive. */
6914 dp->this.ps->validated = 1;
6915}
6916
6917static void PNGCBAPI
6918transform_end(png_structp ppIn, png_infop pi)
6919{
6920 png_const_structp pp = ppIn;
6921 transform_display *dp = voidcast(transform_display*,
6922 png_get_progressive_ptr(pp));
6923
6924 if (!dp->this.speed)
6925 transform_image_validate(dp, pp, pi);
6926 else
6927 dp->this.ps->validated = 1;
6928}
6929
6930/* A single test run. */
6931static void
6932transform_test(png_modifier *pmIn, const png_uint_32 idIn,
6933 const image_transform* transform_listIn, const char * const name)
6934{
6935 transform_display d;
6936 context(&pmIn->this, fault);
6937
6938 transform_display_init(&d, pmIn, idIn, transform_listIn);
6939
6940 Try
6941 {
6942 size_t pos = 0;
6943 png_structp pp;
6944 png_infop pi;
6945 char full_name[256];
6946
6947 /* Make sure the encoding fields are correct and enter the required
6948 * modifications.
6949 */
6950 transform_set_encoding(&d);
6951
6952 /* Add any modifications required by the transform list. */
6953 d.transform_list->ini(d.transform_list, &d);
6954
6955 /* Add the color space information, if any, to the name. */
6956 pos = safecat(full_name, sizeof full_name, pos, name);
6957 pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
6958
6959 /* Get a png_struct for reading the image. */
6960 pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
6961 standard_palette_init(&d.this);
6962
6963# if 0
6964 /* Logging (debugging only) */
6965 {
6966 char buffer[256];
6967
6968 (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
6969 "running test");
6970
6971 fprintf(stderr, "%s\n", buffer);
6972 }
6973# endif
6974
6975 /* Introduce the correct read function. */
6976 if (d.pm->this.progressive)
6977 {
6978 /* Share the row function with the standard implementation. */
6979 png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
6980 transform_end);
6981
6982 /* Now feed data into the reader until we reach the end: */
6983 modifier_progressive_read(d.pm, pp, pi);
6984 }
6985 else
6986 {
6987 /* modifier_read expects a png_modifier* */
6988 png_set_read_fn(pp, d.pm, modifier_read);
6989
6990 /* Check the header values: */
6991 png_read_info(pp, pi);
6992
6993 /* Process the 'info' requirements. Only one image is generated */
6994 transform_info_imp(&d, pp, pi);
6995
6996 sequential_row(&d.this, pp, pi, -1, 0);
6997
6998 if (!d.this.speed)
6999 transform_image_validate(&d, pp, pi);
7000 else
7001 d.this.ps->validated = 1;
7002 }
7003
7004 modifier_reset(d.pm);
7005 }
7006
7007 Catch(fault)
7008 {
7009 modifier_reset(voidcast(png_modifier*,(void*)fault));
7010 }
7011}
7012
7013/* The transforms: */
7014#define ITSTRUCT(name) image_transform_##name
7015#define ITDATA(name) image_transform_data_##name
7016#define image_transform_ini image_transform_default_ini
7017#define IT(name)\
7018static image_transform ITSTRUCT(name) =\
7019{\
7020 #name,\
7021 1, /*enable*/\
7022 &PT, /*list*/\
7023 0, /*global_use*/\
7024 0, /*local_use*/\
7025 0, /*next*/\
7026 image_transform_ini,\
7027 image_transform_png_set_##name##_set,\
7028 image_transform_png_set_##name##_mod,\
7029 image_transform_png_set_##name##_add\
7030}
7031#define PT ITSTRUCT(end) /* stores the previous transform */
7032
7033/* To save code: */
7034extern void image_transform_default_ini(const image_transform *this,
7035 transform_display *that); /* silence GCC warnings */
7036
7037void /* private, but almost always needed */
7038image_transform_default_ini(const image_transform *this,
7039 transform_display *that)
7040{
7041 this->next->ini(this->next, that);
7042}
7043
7044#ifdef PNG_READ_BACKGROUND_SUPPORTED
7045static int
7046image_transform_default_add(image_transform *this,
7047 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7048{
7049 UNUSED(colour_type)
7050 UNUSED(bit_depth)
7051
7052 this->next = *that;
7053 *that = this;
7054
7055 return 1;
7056}
7057#endif
7058
7059#ifdef PNG_READ_EXPAND_SUPPORTED
7060/* png_set_palette_to_rgb */
7061static void
7062image_transform_png_set_palette_to_rgb_set(const image_transform *this,
7063 transform_display *that, png_structp pp, png_infop pi)
7064{
7065 png_set_palette_to_rgb(pp);
7066 this->next->set(this->next, that, pp, pi);
7067}
7068
7069static void
7070image_transform_png_set_palette_to_rgb_mod(const image_transform *this,
7071 image_pixel *that, png_const_structp pp,
7072 const transform_display *display)
7073{
7074 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7075 image_pixel_convert_PLTE(that);
7076
7077 this->next->mod(this->next, that, pp, display);
7078}
7079
7080static int
7081image_transform_png_set_palette_to_rgb_add(image_transform *this,
7082 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7083{
7084 UNUSED(bit_depth)
7085
7086 this->next = *that;
7087 *that = this;
7088
7089 return colour_type == PNG_COLOR_TYPE_PALETTE;
7090}
7091
7092IT(palette_to_rgb);
7093#undef PT
7094#define PT ITSTRUCT(palette_to_rgb)
7095#endif /* PNG_READ_EXPAND_SUPPORTED */
7096
7097#ifdef PNG_READ_EXPAND_SUPPORTED
7098/* png_set_tRNS_to_alpha */
7099static void
7100image_transform_png_set_tRNS_to_alpha_set(const image_transform *this,
7101 transform_display *that, png_structp pp, png_infop pi)
7102{
7103 png_set_tRNS_to_alpha(pp);
7104
7105 /* If there was a tRNS chunk that would get expanded and add an alpha
7106 * channel is_transparent must be updated:
7107 */
7108 if (that->this.has_tRNS)
7109 that->this.is_transparent = 1;
7110
7111 this->next->set(this->next, that, pp, pi);
7112}
7113
7114static void
7115image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this,
7116 image_pixel *that, png_const_structp pp,
7117 const transform_display *display)
7118{
7119#if PNG_LIBPNG_VER < 10700
7120 /* LIBPNG BUG: this always forces palette images to RGB. */
7121 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7122 image_pixel_convert_PLTE(that);
7123#endif
7124
7125 /* This effectively does an 'expand' only if there is some transparency to
7126 * convert to an alpha channel.
7127 */
7128 if (that->have_tRNS)
7129# if PNG_LIBPNG_VER >= 10700
7130 if (that->colour_type != PNG_COLOR_TYPE_PALETTE &&
7131 (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
7132# endif
7133 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7134
7135#if PNG_LIBPNG_VER < 10700
7136 /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
7137 else
7138 {
7139 if (that->bit_depth < 8)
7140 that->bit_depth =8;
7141 if (that->sample_depth < 8)
7142 that->sample_depth = 8;
7143 }
7144#endif
7145
7146 this->next->mod(this->next, that, pp, display);
7147}
7148
7149static int
7150image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
7151 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7152{
7153 UNUSED(bit_depth)
7154
7155 this->next = *that;
7156 *that = this;
7157
7158 /* We don't know yet whether there will be a tRNS chunk, but we know that
7159 * this transformation should do nothing if there already is an alpha
7160 * channel. In addition, after the bug fix in 1.7.0, there is no longer
7161 * any action on a palette image.
7162 */
7163 return
7164# if PNG_LIBPNG_VER >= 10700
7165 colour_type != PNG_COLOR_TYPE_PALETTE &&
7166# endif
7167 (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7168}
7169
7170IT(tRNS_to_alpha);
7171#undef PT
7172#define PT ITSTRUCT(tRNS_to_alpha)
7173#endif /* PNG_READ_EXPAND_SUPPORTED */
7174
7175#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
7176/* png_set_gray_to_rgb */
7177static void
7178image_transform_png_set_gray_to_rgb_set(const image_transform *this,
7179 transform_display *that, png_structp pp, png_infop pi)
7180{
7181 png_set_gray_to_rgb(pp);
7182 /* NOTE: this doesn't result in tRNS expansion. */
7183 this->next->set(this->next, that, pp, pi);
7184}
7185
7186static void
7187image_transform_png_set_gray_to_rgb_mod(const image_transform *this,
7188 image_pixel *that, png_const_structp pp,
7189 const transform_display *display)
7190{
7191 /* NOTE: we can actually pend the tRNS processing at this point because we
7192 * can correctly recognize the original pixel value even though we have
7193 * mapped the one gray channel to the three RGB ones, but in fact libpng
7194 * doesn't do this, so we don't either.
7195 */
7196 if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
7197 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7198
7199 /* Simply expand the bit depth and alter the colour type as required. */
7200 if (that->colour_type == PNG_COLOR_TYPE_GRAY)
7201 {
7202 /* RGB images have a bit depth at least equal to '8' */
7203 if (that->bit_depth < 8)
7204 that->sample_depth = that->bit_depth = 8;
7205
7206 /* And just changing the colour type works here because the green and blue
7207 * channels are being maintained in lock-step with the red/gray:
7208 */
7209 that->colour_type = PNG_COLOR_TYPE_RGB;
7210 }
7211
7212 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7213 that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
7214
7215 this->next->mod(this->next, that, pp, display);
7216}
7217
7218static int
7219image_transform_png_set_gray_to_rgb_add(image_transform *this,
7220 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7221{
7222 UNUSED(bit_depth)
7223
7224 this->next = *that;
7225 *that = this;
7226
7227 return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
7228}
7229
7230IT(gray_to_rgb);
7231#undef PT
7232#define PT ITSTRUCT(gray_to_rgb)
7233#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
7234
7235#ifdef PNG_READ_EXPAND_SUPPORTED
7236/* png_set_expand */
7237static void
7238image_transform_png_set_expand_set(const image_transform *this,
7239 transform_display *that, png_structp pp, png_infop pi)
7240{
7241 png_set_expand(pp);
7242
7243 if (that->this.has_tRNS)
7244 that->this.is_transparent = 1;
7245
7246 this->next->set(this->next, that, pp, pi);
7247}
7248
7249static void
7250image_transform_png_set_expand_mod(const image_transform *this,
7251 image_pixel *that, png_const_structp pp,
7252 const transform_display *display)
7253{
7254 /* The general expand case depends on what the colour type is: */
7255 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7256 image_pixel_convert_PLTE(that);
7257 else if (that->bit_depth < 8) /* grayscale */
7258 that->sample_depth = that->bit_depth = 8;
7259
7260 if (that->have_tRNS)
7261 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7262
7263 this->next->mod(this->next, that, pp, display);
7264}
7265
7266static int
7267image_transform_png_set_expand_add(image_transform *this,
7268 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7269{
7270 UNUSED(bit_depth)
7271
7272 this->next = *that;
7273 *that = this;
7274
7275 /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
7276 * depth is at least 8 already.
7277 */
7278 return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7279}
7280
7281IT(expand);
7282#undef PT
7283#define PT ITSTRUCT(expand)
7284#endif /* PNG_READ_EXPAND_SUPPORTED */
7285
7286#ifdef PNG_READ_EXPAND_SUPPORTED
7287/* png_set_expand_gray_1_2_4_to_8
7288 * Pre 1.7.0 LIBPNG BUG: this just does an 'expand'
7289 */
7290static void
7291image_transform_png_set_expand_gray_1_2_4_to_8_set(
7292 const image_transform *this, transform_display *that, png_structp pp,
7293 png_infop pi)
7294{
7295 png_set_expand_gray_1_2_4_to_8(pp);
7296 /* NOTE: don't expect this to expand tRNS */
7297 this->next->set(this->next, that, pp, pi);
7298}
7299
7300static void
7301image_transform_png_set_expand_gray_1_2_4_to_8_mod(
7302 const image_transform *this, image_pixel *that, png_const_structp pp,
7303 const transform_display *display)
7304{
7305#if PNG_LIBPNG_VER < 10700
7306 image_transform_png_set_expand_mod(this, that, pp, display);
7307#else
7308 /* Only expand grayscale of bit depth less than 8: */
7309 if (that->colour_type == PNG_COLOR_TYPE_GRAY &&
7310 that->bit_depth < 8)
7311 that->sample_depth = that->bit_depth = 8;
7312
7313 this->next->mod(this->next, that, pp, display);
7314#endif /* 1.7 or later */
7315}
7316
7317static int
7318image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
7319 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7320{
7321#if PNG_LIBPNG_VER < 10700
7322 return image_transform_png_set_expand_add(this, that, colour_type,
7323 bit_depth);
7324#else
7325 UNUSED(bit_depth)
7326
7327 this->next = *that;
7328 *that = this;
7329
7330 /* This should do nothing unless the color type is gray and the bit depth is
7331 * less than 8:
7332 */
7333 return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8;
7334#endif /* 1.7 or later */
7335}
7336
7337IT(expand_gray_1_2_4_to_8);
7338#undef PT
7339#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
7340#endif /* PNG_READ_EXPAND_SUPPORTED */
7341
7342#ifdef PNG_READ_EXPAND_16_SUPPORTED
7343/* png_set_expand_16 */
7344static void
7345image_transform_png_set_expand_16_set(const image_transform *this,
7346 transform_display *that, png_structp pp, png_infop pi)
7347{
7348 png_set_expand_16(pp);
7349
7350 /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */
7351# if PNG_LIBPNG_VER < 10700
7352 if (that->this.has_tRNS)
7353 that->this.is_transparent = 1;
7354# endif
7355
7356 this->next->set(this->next, that, pp, pi);
7357}
7358
7359static void
7360image_transform_png_set_expand_16_mod(const image_transform *this,
7361 image_pixel *that, png_const_structp pp,
7362 const transform_display *display)
7363{
7364 /* Expect expand_16 to expand everything to 16 bits as a result of also
7365 * causing 'expand' to happen.
7366 */
7367 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7368 image_pixel_convert_PLTE(that);
7369
7370 if (that->have_tRNS)
7371 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7372
7373 if (that->bit_depth < 16)
7374 that->sample_depth = that->bit_depth = 16;
7375
7376 this->next->mod(this->next, that, pp, display);
7377}
7378
7379static int
7380image_transform_png_set_expand_16_add(image_transform *this,
7381 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7382{
7383 UNUSED(colour_type)
7384
7385 this->next = *that;
7386 *that = this;
7387
7388 /* expand_16 does something unless the bit depth is already 16. */
7389 return bit_depth < 16;
7390}
7391
7392IT(expand_16);
7393#undef PT
7394#define PT ITSTRUCT(expand_16)
7395#endif /* PNG_READ_EXPAND_16_SUPPORTED */
7396
7397#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
7398/* png_set_scale_16 */
7399static void
7400image_transform_png_set_scale_16_set(const image_transform *this,
7401 transform_display *that, png_structp pp, png_infop pi)
7402{
7403 png_set_scale_16(pp);
7404# if PNG_LIBPNG_VER < 10700
7405 /* libpng will limit the gamma table size: */
7406 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7407# endif
7408 this->next->set(this->next, that, pp, pi);
7409}
7410
7411static void
7412image_transform_png_set_scale_16_mod(const image_transform *this,
7413 image_pixel *that, png_const_structp pp,
7414 const transform_display *display)
7415{
7416 if (that->bit_depth == 16)
7417 {
7418 that->sample_depth = that->bit_depth = 8;
7419 if (that->red_sBIT > 8) that->red_sBIT = 8;
7420 if (that->green_sBIT > 8) that->green_sBIT = 8;
7421 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7422 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7423 }
7424
7425 this->next->mod(this->next, that, pp, display);
7426}
7427
7428static int
7429image_transform_png_set_scale_16_add(image_transform *this,
7430 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7431{
7432 UNUSED(colour_type)
7433
7434 this->next = *that;
7435 *that = this;
7436
7437 return bit_depth > 8;
7438}
7439
7440IT(scale_16);
7441#undef PT
7442#define PT ITSTRUCT(scale_16)
7443#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
7444
7445#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
7446/* png_set_strip_16 */
7447static void
7448image_transform_png_set_strip_16_set(const image_transform *this,
7449 transform_display *that, png_structp pp, png_infop pi)
7450{
7451 png_set_strip_16(pp);
7452# if PNG_LIBPNG_VER < 10700
7453 /* libpng will limit the gamma table size: */
7454 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7455# endif
7456 this->next->set(this->next, that, pp, pi);
7457}
7458
7459static void
7460image_transform_png_set_strip_16_mod(const image_transform *this,
7461 image_pixel *that, png_const_structp pp,
7462 const transform_display *display)
7463{
7464 if (that->bit_depth == 16)
7465 {
7466 that->sample_depth = that->bit_depth = 8;
7467 if (that->red_sBIT > 8) that->red_sBIT = 8;
7468 if (that->green_sBIT > 8) that->green_sBIT = 8;
7469 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7470 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7471
7472 /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
7473 * configuration option is set. From 1.5.4 the flag is never set and the
7474 * 'scale' API (above) must be used.
7475 */
7476# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
7477# if PNG_LIBPNG_VER >= 10504
7478# error PNG_READ_ACCURATE_SCALE should not be set
7479# endif
7480
7481 /* The strip 16 algorithm drops the low 8 bits rather than calculating
7482 * 1/257, so we need to adjust the permitted errors appropriately:
7483 * Notice that this is only relevant prior to the addition of the
7484 * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
7485 */
7486 {
7487 const double d = (255-128.5)/65535;
7488 that->rede += d;
7489 that->greene += d;
7490 that->bluee += d;
7491 that->alphae += d;
7492 }
7493# endif
7494 }
7495
7496 this->next->mod(this->next, that, pp, display);
7497}
7498
7499static int
7500image_transform_png_set_strip_16_add(image_transform *this,
7501 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7502{
7503 UNUSED(colour_type)
7504
7505 this->next = *that;
7506 *that = this;
7507
7508 return bit_depth > 8;
7509}
7510
7511IT(strip_16);
7512#undef PT
7513#define PT ITSTRUCT(strip_16)
7514#endif /* PNG_READ_16_TO_8_SUPPORTED */
7515
7516#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
7517/* png_set_strip_alpha */
7518static void
7519image_transform_png_set_strip_alpha_set(const image_transform *this,
7520 transform_display *that, png_structp pp, png_infop pi)
7521{
7522 png_set_strip_alpha(pp);
7523 this->next->set(this->next, that, pp, pi);
7524}
7525
7526static void
7527image_transform_png_set_strip_alpha_mod(const image_transform *this,
7528 image_pixel *that, png_const_structp pp,
7529 const transform_display *display)
7530{
7531 if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7532 that->colour_type = PNG_COLOR_TYPE_GRAY;
7533 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
7534 that->colour_type = PNG_COLOR_TYPE_RGB;
7535
7536 that->have_tRNS = 0;
7537 that->alphaf = 1;
7538
7539 this->next->mod(this->next, that, pp, display);
7540}
7541
7542static int
7543image_transform_png_set_strip_alpha_add(image_transform *this,
7544 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7545{
7546 UNUSED(bit_depth)
7547
7548 this->next = *that;
7549 *that = this;
7550
7551 return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
7552}
7553
7554IT(strip_alpha);
7555#undef PT
7556#define PT ITSTRUCT(strip_alpha)
7557#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
7558
7559#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
7560/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
7561 * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
7562 * png_fixed_point green)
7563 * png_get_rgb_to_gray_status
7564 *
7565 * The 'default' test here uses values known to be used inside libpng prior to
7566 * 1.7.0:
7567 *
7568 * red: 6968
7569 * green: 23434
7570 * blue: 2366
7571 *
7572 * These values are being retained for compatibility, along with the somewhat
7573 * broken truncation calculation in the fast-and-inaccurate code path. Older
7574 * versions of libpng will fail the accuracy tests below because they use the
7575 * truncation algorithm everywhere.
7576 */
7577#define data ITDATA(rgb_to_gray)
7578static struct
7579{
7580 double gamma; /* File gamma to use in processing */
7581
7582 /* The following are the parameters for png_set_rgb_to_gray: */
7583# ifdef PNG_FLOATING_POINT_SUPPORTED
7584 double red_to_set;
7585 double green_to_set;
7586# else
7587 png_fixed_point red_to_set;
7588 png_fixed_point green_to_set;
7589# endif
7590
7591 /* The actual coefficients: */
7592 double red_coefficient;
7593 double green_coefficient;
7594 double blue_coefficient;
7595
7596 /* Set if the coeefficients have been overridden. */
7597 int coefficients_overridden;
7598} data;
7599
7600#undef image_transform_ini
7601#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
7602static void
7603image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
7604 transform_display *that)
7605{
7606 png_modifier *pm = that->pm;
7607 const color_encoding *e = pm->current_encoding;
7608
7609 UNUSED(this)
7610
7611 /* Since we check the encoding this flag must be set: */
7612 pm->test_uses_encoding = 1;
7613
7614 /* If 'e' is not NULL chromaticity information is present and either a cHRM
7615 * or an sRGB chunk will be inserted.
7616 */
7617 if (e != 0)
7618 {
7619 /* Coefficients come from the encoding, but may need to be normalized to a
7620 * white point Y of 1.0
7621 */
7622 const double whiteY = e->red.Y + e->green.Y + e->blue.Y;
7623
7624 data.red_coefficient = e->red.Y;
7625 data.green_coefficient = e->green.Y;
7626 data.blue_coefficient = e->blue.Y;
7627
7628 if (whiteY != 1)
7629 {
7630 data.red_coefficient /= whiteY;
7631 data.green_coefficient /= whiteY;
7632 data.blue_coefficient /= whiteY;
7633 }
7634 }
7635
7636 else
7637 {
7638 /* The default (built in) coeffcients, as above: */
7639# if PNG_LIBPNG_VER < 10700
7640 data.red_coefficient = 6968 / 32768.;
7641 data.green_coefficient = 23434 / 32768.;
7642 data.blue_coefficient = 2366 / 32768.;
7643# else
7644 data.red_coefficient = .2126;
7645 data.green_coefficient = .7152;
7646 data.blue_coefficient = .0722;
7647# endif
7648 }
7649
7650 data.gamma = pm->current_gamma;
7651
7652 /* If not set then the calculations assume linear encoding (implicitly): */
7653 if (data.gamma == 0)
7654 data.gamma = 1;
7655
7656 /* The arguments to png_set_rgb_to_gray can override the coefficients implied
7657 * by the color space encoding. If doing exhaustive checks do the override
7658 * in each case, otherwise do it randomly.
7659 */
7660 if (pm->test_exhaustive)
7661 {
7662 /* First time in coefficients_overridden is 0, the following sets it to 1,
7663 * so repeat if it is set. If a test fails this may mean we subsequently
7664 * skip a non-override test, ignore that.
7665 */
7666 data.coefficients_overridden = !data.coefficients_overridden;
7667 pm->repeat = data.coefficients_overridden != 0;
7668 }
7669
7670 else
7671 data.coefficients_overridden = random_choice();
7672
7673 if (data.coefficients_overridden)
7674 {
7675 /* These values override the color encoding defaults, simply use random
7676 * numbers.
7677 */
7678 png_uint_32 ru;
7679 double total;
7680
7681 ru = random_u32();
7682 data.green_coefficient = total = (ru & 0xffff) / 65535.;
7683 ru >>= 16;
7684 data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
7685 total += data.red_coefficient;
7686 data.blue_coefficient = 1 - total;
7687
7688# ifdef PNG_FLOATING_POINT_SUPPORTED
7689 data.red_to_set = data.red_coefficient;
7690 data.green_to_set = data.green_coefficient;
7691# else
7692 data.red_to_set = fix(data.red_coefficient);
7693 data.green_to_set = fix(data.green_coefficient);
7694# endif
7695
7696 /* The following just changes the error messages: */
7697 pm->encoding_ignored = 1;
7698 }
7699
7700 else
7701 {
7702 data.red_to_set = -1;
7703 data.green_to_set = -1;
7704 }
7705
7706 /* Adjust the error limit in the png_modifier because of the larger errors
7707 * produced in the digitization during the gamma handling.
7708 */
7709 if (data.gamma != 1) /* Use gamma tables */
7710 {
7711 if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
7712 {
7713 /* The computations have the form:
7714 *
7715 * r * rc + g * gc + b * bc
7716 *
7717 * Each component of which is +/-1/65535 from the gamma_to_1 table
7718 * lookup, resulting in a base error of +/-6. The gamma_from_1
7719 * conversion adds another +/-2 in the 16-bit case and
7720 * +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
7721 */
7722# if PNG_LIBPNG_VER < 10700
7723 if (that->this.bit_depth < 16)
7724 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7725# endif
7726 that->pm->limit += pow(
7727 (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ?
7728 8. :
7729 6. + (1<<(15-that->max_gamma_8))
7730 )/65535, data.gamma);
7731 }
7732
7733 else
7734 {
7735 /* Rounding to 8 bits in the linear space causes massive errors which
7736 * will trigger the error check in transform_range_check. Fix that
7737 * here by taking the gamma encoding into account.
7738 *
7739 * When DIGITIZE is set because a pre-1.7 version of libpng is being
7740 * tested allow a bigger slack.
7741 *
7742 * NOTE: this number only affects the internal limit check in pngvalid,
7743 * it has no effect on the limits applied to the libpng values.
7744 */
7745#if DIGITIZE
7746 that->pm->limit += pow( 2.0/255, data.gamma);
7747#else
7748 that->pm->limit += pow( 1.0/255, data.gamma);
7749#endif
7750 }
7751 }
7752
7753 else
7754 {
7755 /* With no gamma correction a large error comes from the truncation of the
7756 * calculation in the 8 bit case, allow for that here.
7757 */
7758 if (that->this.bit_depth != 16 && !pm->assume_16_bit_calculations)
7759 that->pm->limit += 4E-3;
7760 }
7761}
7762
7763static void
7764image_transform_png_set_rgb_to_gray_set(const image_transform *this,
7765 transform_display *that, png_structp pp, png_infop pi)
7766{
7767 const int error_action = 1; /* no error, no defines in png.h */
7768
7769# ifdef PNG_FLOATING_POINT_SUPPORTED
7770 png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
7771# else
7772 png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
7773 data.green_to_set);
7774# endif
7775
7776# ifdef PNG_READ_cHRM_SUPPORTED
7777 if (that->pm->current_encoding != 0)
7778 {
7779 /* We have an encoding so a cHRM chunk may have been set; if so then
7780 * check that the libpng APIs give the correct (X,Y,Z) values within
7781 * some margin of error for the round trip through the chromaticity
7782 * form.
7783 */
7784# ifdef PNG_FLOATING_POINT_SUPPORTED
7785# define API_function png_get_cHRM_XYZ
7786# define API_form "FP"
7787# define API_type double
7788# define API_cvt(x) (x)
7789# else
7790# define API_function png_get_cHRM_XYZ_fixed
7791# define API_form "fixed"
7792# define API_type png_fixed_point
7793# define API_cvt(x) ((double)(x)/PNG_FP_1)
7794# endif
7795
7796 API_type rX, gX, bX;
7797 API_type rY, gY, bY;
7798 API_type rZ, gZ, bZ;
7799
7800 if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
7801 & PNG_INFO_cHRM) != 0)
7802 {
7803 double maxe;
7804 const char *el;
7805 color_encoding e, o;
7806
7807 /* Expect libpng to return a normalized result, but the original
7808 * color space encoding may not be normalized.
7809 */
7810 modifier_current_encoding(that->pm, &o);
7811 normalize_color_encoding(&o);
7812
7813 /* Sanity check the pngvalid code - the coefficients should match
7814 * the normalized Y values of the encoding unless they were
7815 * overridden.
7816 */
7817 if (data.red_to_set == -1 && data.green_to_set == -1 &&
7818 (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
7819 fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
7820 fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
7821 png_error(pp, "internal pngvalid cHRM coefficient error");
7822
7823 /* Generate a colour space encoding. */
7824 e.gamma = o.gamma; /* not used */
7825 e.red.X = API_cvt(rX);
7826 e.red.Y = API_cvt(rY);
7827 e.red.Z = API_cvt(rZ);
7828 e.green.X = API_cvt(gX);
7829 e.green.Y = API_cvt(gY);
7830 e.green.Z = API_cvt(gZ);
7831 e.blue.X = API_cvt(bX);
7832 e.blue.Y = API_cvt(bY);
7833 e.blue.Z = API_cvt(bZ);
7834
7835 /* This should match the original one from the png_modifier, within
7836 * the range permitted by the libpng fixed point representation.
7837 */
7838 maxe = 0;
7839 el = "-"; /* Set to element name with error */
7840
7841# define CHECK(col,x)\
7842 {\
7843 double err = fabs(o.col.x - e.col.x);\
7844 if (err > maxe)\
7845 {\
7846 maxe = err;\
7847 el = #col "(" #x ")";\
7848 }\
7849 }
7850
7851 CHECK(red,X)
7852 CHECK(red,Y)
7853 CHECK(red,Z)
7854 CHECK(green,X)
7855 CHECK(green,Y)
7856 CHECK(green,Z)
7857 CHECK(blue,X)
7858 CHECK(blue,Y)
7859 CHECK(blue,Z)
7860
7861 /* Here in both fixed and floating cases to check the values read
7862 * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
7863 * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
7864 */
7865 if (maxe >= 1E-5)
7866 {
7867 size_t pos = 0;
7868 char buffer[256];
7869
7870 pos = safecat(buffer, sizeof buffer, pos, API_form);
7871 pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
7872 pos = safecat(buffer, sizeof buffer, pos, el);
7873 pos = safecat(buffer, sizeof buffer, pos, " error: ");
7874 pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
7875 pos = safecat(buffer, sizeof buffer, pos, " ");
7876 /* Print the color space without the gamma value: */
7877 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
7878 pos = safecat(buffer, sizeof buffer, pos, " -> ");
7879 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
7880
7881 png_error(pp, buffer);
7882 }
7883 }
7884 }
7885# endif /* READ_cHRM */
7886
7887 this->next->set(this->next, that, pp, pi);
7888}
7889
7890static void
7891image_transform_png_set_rgb_to_gray_mod(const image_transform *this,
7892 image_pixel *that, png_const_structp pp,
7893 const transform_display *display)
7894{
7895 if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
7896 {
7897 double gray, err;
7898
7899# if PNG_LIBPNG_VER < 10700
7900 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7901 image_pixel_convert_PLTE(that);
7902# endif
7903
7904 /* Image now has RGB channels... */
7905# if DIGITIZE
7906 {
7907 png_modifier *pm = display->pm;
7908 const unsigned int sample_depth = that->sample_depth;
7909 const unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 :
7910 sample_depth);
7911 const unsigned int gamma_depth =
7912 (sample_depth == 16 ?
7913 display->max_gamma_8 :
7914 (pm->assume_16_bit_calculations ?
7915 display->max_gamma_8 :
7916 sample_depth));
7917 int isgray;
7918 double r, g, b;
7919 double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
7920
7921 /* Do this using interval arithmetic, otherwise it is too difficult to
7922 * handle the errors correctly.
7923 *
7924 * To handle the gamma correction work out the upper and lower bounds
7925 * of the digitized value. Assume rounding here - normally the values
7926 * will be identical after this operation if there is only one
7927 * transform, feel free to delete the png_error checks on this below in
7928 * the future (this is just me trying to ensure it works!)
7929 *
7930 * Interval arithmetic is exact, but to implement it it must be
7931 * possible to control the floating point implementation rounding mode.
7932 * This cannot be done in ANSI-C, so instead I reduce the 'lo' values
7933 * by DBL_EPSILON and increase the 'hi' values by the same.
7934 */
7935# define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON))
7936# define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON))
7937
7938 r = rlo = rhi = that->redf;
7939 rlo -= that->rede;
7940 rlo = DD(rlo, calc_depth, 1/*round*/);
7941 rhi += that->rede;
7942 rhi = DU(rhi, calc_depth, 1/*round*/);
7943
7944 g = glo = ghi = that->greenf;
7945 glo -= that->greene;
7946 glo = DD(glo, calc_depth, 1/*round*/);
7947 ghi += that->greene;
7948 ghi = DU(ghi, calc_depth, 1/*round*/);
7949
7950 b = blo = bhi = that->bluef;
7951 blo -= that->bluee;
7952 blo = DD(blo, calc_depth, 1/*round*/);
7953 bhi += that->bluee;
7954 bhi = DU(bhi, calc_depth, 1/*round*/);
7955
7956 isgray = r==g && g==b;
7957
7958 if (data.gamma != 1)
7959 {
7960 const double power = 1/data.gamma;
7961 const double abse = .5/(sample_depth == 16 ? 65535 : 255);
7962
7963 /* If a gamma calculation is done it is done using lookup tables of
7964 * precision gamma_depth, so the already digitized value above may
7965 * need to be further digitized here.
7966 */
7967 if (gamma_depth != calc_depth)
7968 {
7969 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
7970 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
7971 glo = DD(glo, gamma_depth, 0/*truncate*/);
7972 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
7973 blo = DD(blo, gamma_depth, 0/*truncate*/);
7974 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
7975 }
7976
7977 /* 'abse' is the error in the gamma table calculation itself. */
7978 r = pow(r, power);
7979 rlo = DD(pow(rlo, power)-abse, calc_depth, 1);
7980 rhi = DU(pow(rhi, power)+abse, calc_depth, 1);
7981
7982 g = pow(g, power);
7983 glo = DD(pow(glo, power)-abse, calc_depth, 1);
7984 ghi = DU(pow(ghi, power)+abse, calc_depth, 1);
7985
7986 b = pow(b, power);
7987 blo = DD(pow(blo, power)-abse, calc_depth, 1);
7988 bhi = DU(pow(bhi, power)+abse, calc_depth, 1);
7989 }
7990
7991 /* Now calculate the actual gray values. Although the error in the
7992 * coefficients depends on whether they were specified on the command
7993 * line (in which case truncation to 15 bits happened) or not (rounding
7994 * was used) the maxium error in an individual coefficient is always
7995 * 2/32768, because even in the rounding case the requirement that
7996 * coefficients add up to 32768 can cause a larger rounding error.
7997 *
7998 * The only time when rounding doesn't occur in 1.5.5 and later is when
7999 * the non-gamma code path is used for less than 16 bit data.
8000 */
8001 gray = r * data.red_coefficient + g * data.green_coefficient +
8002 b * data.blue_coefficient;
8003
8004 {
8005 const int do_round = data.gamma != 1 || calc_depth == 16;
8006 const double ce = 2. / 32768;
8007
8008 graylo = DD(rlo * (data.red_coefficient-ce) +
8009 glo * (data.green_coefficient-ce) +
8010 blo * (data.blue_coefficient-ce), calc_depth, do_round);
8011 if (graylo > gray) /* always accept the right answer */
8012 graylo = gray;
8013
8014 grayhi = DU(rhi * (data.red_coefficient+ce) +
8015 ghi * (data.green_coefficient+ce) +
8016 bhi * (data.blue_coefficient+ce), calc_depth, do_round);
8017 if (grayhi < gray)
8018 grayhi = gray;
8019 }
8020
8021 /* And invert the gamma. */
8022 if (data.gamma != 1)
8023 {
8024 const double power = data.gamma;
8025
8026 /* And this happens yet again, shifting the values once more. */
8027 if (gamma_depth != sample_depth)
8028 {
8029 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
8030 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
8031 glo = DD(glo, gamma_depth, 0/*truncate*/);
8032 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
8033 blo = DD(blo, gamma_depth, 0/*truncate*/);
8034 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
8035 }
8036
8037 gray = pow(gray, power);
8038 graylo = DD(pow(graylo, power), sample_depth, 1);
8039 grayhi = DU(pow(grayhi, power), sample_depth, 1);
8040 }
8041
8042# undef DD
8043# undef DU
8044
8045 /* Now the error can be calculated.
8046 *
8047 * If r==g==b because there is no overall gamma correction libpng
8048 * currently preserves the original value.
8049 */
8050 if (isgray)
8051 err = (that->rede + that->greene + that->bluee)/3;
8052
8053 else
8054 {
8055 err = fabs(grayhi-gray);
8056
8057 if (fabs(gray - graylo) > err)
8058 err = fabs(graylo-gray);
8059
8060#if !RELEASE_BUILD
8061 /* Check that this worked: */
8062 if (err > pm->limit)
8063 {
8064 size_t pos = 0;
8065 char buffer[128];
8066
8067 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8068 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8069 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8070 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8071 png_warning(pp, buffer);
8072 pm->limit = err;
8073 }
8074#endif /* !RELEASE_BUILD */
8075 }
8076 }
8077# else /* !DIGITIZE */
8078 {
8079 double r = that->redf;
8080 double re = that->rede;
8081 double g = that->greenf;
8082 double ge = that->greene;
8083 double b = that->bluef;
8084 double be = that->bluee;
8085
8086# if PNG_LIBPNG_VER < 10700
8087 /* The true gray case involves no math in earlier versions (not
8088 * true, there was some if gamma correction was happening too.)
8089 */
8090 if (r == g && r == b)
8091 {
8092 gray = r;
8093 err = re;
8094 if (err < ge) err = ge;
8095 if (err < be) err = be;
8096 }
8097
8098 else
8099# endif /* before 1.7 */
8100 if (data.gamma == 1)
8101 {
8102 /* There is no need to do the conversions to and from linear space,
8103 * so the calculation should be a lot more accurate. There is a
8104 * built in error in the coefficients because they only have 15 bits
8105 * and are adjusted to make sure they add up to 32768. This
8106 * involves a integer calculation with truncation of the form:
8107 *
8108 * ((int)(coefficient * 100000) * 32768)/100000
8109 *
8110 * This is done to the red and green coefficients (the ones
8111 * provided to the API) then blue is calculated from them so the
8112 * result adds up to 32768. In the worst case this can result in
8113 * a -1 error in red and green and a +2 error in blue. Consequently
8114 * the worst case in the calculation below is 2/32768 error.
8115 *
8116 * TODO: consider fixing this in libpng by rounding the calculation
8117 * limiting the error to 1/32768.
8118 *
8119 * Handling this by adding 2/32768 here avoids needing to increase
8120 * the global error limits to take this into account.)
8121 */
8122 gray = r * data.red_coefficient + g * data.green_coefficient +
8123 b * data.blue_coefficient;
8124 err = re * data.red_coefficient + ge * data.green_coefficient +
8125 be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON;
8126 }
8127
8128 else
8129 {
8130 /* The calculation happens in linear space, and this produces much
8131 * wider errors in the encoded space. These are handled here by
8132 * factoring the errors in to the calculation. There are two table
8133 * lookups in the calculation and each introduces a quantization
8134 * error defined by the table size.
8135 */
8136 png_modifier *pm = display->pm;
8137 double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255);
8138 double out_qe = (that->sample_depth > 8 ? .5/65535 :
8139 (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) :
8140 .5/255));
8141 double rhi, ghi, bhi, grayhi;
8142 double g1 = 1/data.gamma;
8143
8144 rhi = r + re + in_qe; if (rhi > 1) rhi = 1;
8145 r -= re + in_qe; if (r < 0) r = 0;
8146 ghi = g + ge + in_qe; if (ghi > 1) ghi = 1;
8147 g -= ge + in_qe; if (g < 0) g = 0;
8148 bhi = b + be + in_qe; if (bhi > 1) bhi = 1;
8149 b -= be + in_qe; if (b < 0) b = 0;
8150
8151 r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON);
8152 g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON);
8153 b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON);
8154
8155 /* Work out the lower and upper bounds for the gray value in the
8156 * encoded space, then work out an average and error. Remove the
8157 * previously added input quantization error at this point.
8158 */
8159 gray = r * data.red_coefficient + g * data.green_coefficient +
8160 b * data.blue_coefficient - 2./32768 - out_qe;
8161 if (gray <= 0)
8162 gray = 0;
8163 else
8164 {
8165 gray *= (1 - 6 * DBL_EPSILON);
8166 gray = pow(gray, data.gamma) * (1-DBL_EPSILON);
8167 }
8168
8169 grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient +
8170 bhi * data.blue_coefficient + 2./32768 + out_qe;
8171 grayhi *= (1 + 6 * DBL_EPSILON);
8172 if (grayhi >= 1)
8173 grayhi = 1;
8174 else
8175 grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON);
8176
8177 err = (grayhi - gray) / 2;
8178 gray = (grayhi + gray) / 2;
8179
8180 if (err <= in_qe)
8181 err = gray * DBL_EPSILON;
8182
8183 else
8184 err -= in_qe;
8185
8186#if !RELEASE_BUILD
8187 /* Validate that the error is within limits (this has caused
8188 * problems before, it's much easier to detect them here.)
8189 */
8190 if (err > pm->limit)
8191 {
8192 size_t pos = 0;
8193 char buffer[128];
8194
8195 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8196 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8197 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8198 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8199 png_warning(pp, buffer);
8200 pm->limit = err;
8201 }
8202#endif /* !RELEASE_BUILD */
8203 }
8204 }
8205# endif /* !DIGITIZE */
8206
8207 that->bluef = that->greenf = that->redf = gray;
8208 that->bluee = that->greene = that->rede = err;
8209
8210 /* The sBIT is the minium of the three colour channel sBITs. */
8211 if (that->red_sBIT > that->green_sBIT)
8212 that->red_sBIT = that->green_sBIT;
8213 if (that->red_sBIT > that->blue_sBIT)
8214 that->red_sBIT = that->blue_sBIT;
8215 that->blue_sBIT = that->green_sBIT = that->red_sBIT;
8216
8217 /* And remove the colour bit in the type: */
8218 if (that->colour_type == PNG_COLOR_TYPE_RGB)
8219 that->colour_type = PNG_COLOR_TYPE_GRAY;
8220 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8221 that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
8222 }
8223
8224 this->next->mod(this->next, that, pp, display);
8225}
8226
8227static int
8228image_transform_png_set_rgb_to_gray_add(image_transform *this,
8229 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8230{
8231 UNUSED(bit_depth)
8232
8233 this->next = *that;
8234 *that = this;
8235
8236 return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
8237}
8238
8239#undef data
8240IT(rgb_to_gray);
8241#undef PT
8242#define PT ITSTRUCT(rgb_to_gray)
8243#undef image_transform_ini
8244#define image_transform_ini image_transform_default_ini
8245#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
8246
8247#ifdef PNG_READ_BACKGROUND_SUPPORTED
8248/* png_set_background(png_structp, png_const_color_16p background_color,
8249 * int background_gamma_code, int need_expand, double background_gamma)
8250 * png_set_background_fixed(png_structp, png_const_color_16p background_color,
8251 * int background_gamma_code, int need_expand,
8252 * png_fixed_point background_gamma)
8253 *
8254 * This ignores the gamma (at present.)
8255*/
8256#define data ITDATA(background)
8257static image_pixel data;
8258
8259static void
8260image_transform_png_set_background_set(const image_transform *this,
8261 transform_display *that, png_structp pp, png_infop pi)
8262{
8263 png_byte colour_type, bit_depth;
8264 png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
8265 int expand;
8266 png_color_16 back;
8267
8268 /* We need a background colour, because we don't know exactly what transforms
8269 * have been set we have to supply the colour in the original file format and
8270 * so we need to know what that is! The background colour is stored in the
8271 * transform_display.
8272 */
8273 R8(random_bytes);
8274
8275 /* Read the random value, for colour type 3 the background colour is actually
8276 * expressed as a 24bit rgb, not an index.
8277 */
8278 colour_type = that->this.colour_type;
8279 if (colour_type == 3)
8280 {
8281 colour_type = PNG_COLOR_TYPE_RGB;
8282 bit_depth = 8;
8283 expand = 0; /* passing in an RGB not a pixel index */
8284 }
8285
8286 else
8287 {
8288 if (that->this.has_tRNS)
8289 that->this.is_transparent = 1;
8290
8291 bit_depth = that->this.bit_depth;
8292 expand = 1;
8293 }
8294
8295 image_pixel_init(&data, random_bytes, colour_type,
8296 bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/);
8297
8298 /* Extract the background colour from this image_pixel, but make sure the
8299 * unused fields of 'back' are garbage.
8300 */
8301 R8(back);
8302
8303 if (colour_type & PNG_COLOR_MASK_COLOR)
8304 {
8305 back.red = (png_uint_16)data.red;
8306 back.green = (png_uint_16)data.green;
8307 back.blue = (png_uint_16)data.blue;
8308 }
8309
8310 else
8311 back.gray = (png_uint_16)data.red;
8312
8313#ifdef PNG_FLOATING_POINT_SUPPORTED
8314 png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8315#else
8316 png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8317#endif
8318
8319 this->next->set(this->next, that, pp, pi);
8320}
8321
8322static void
8323image_transform_png_set_background_mod(const image_transform *this,
8324 image_pixel *that, png_const_structp pp,
8325 const transform_display *display)
8326{
8327 /* Check for tRNS first: */
8328 if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
8329 image_pixel_add_alpha(that, &display->this, 1/*for background*/);
8330
8331 /* This is only necessary if the alpha value is less than 1. */
8332 if (that->alphaf < 1)
8333 {
8334 /* Now we do the background calculation without any gamma correction. */
8335 if (that->alphaf <= 0)
8336 {
8337 that->redf = data.redf;
8338 that->greenf = data.greenf;
8339 that->bluef = data.bluef;
8340
8341 that->rede = data.rede;
8342 that->greene = data.greene;
8343 that->bluee = data.bluee;
8344
8345 that->red_sBIT= data.red_sBIT;
8346 that->green_sBIT= data.green_sBIT;
8347 that->blue_sBIT= data.blue_sBIT;
8348 }
8349
8350 else /* 0 < alpha < 1 */
8351 {
8352 double alf = 1 - that->alphaf;
8353
8354 that->redf = that->redf * that->alphaf + data.redf * alf;
8355 that->rede = that->rede * that->alphaf + data.rede * alf +
8356 DBL_EPSILON;
8357 that->greenf = that->greenf * that->alphaf + data.greenf * alf;
8358 that->greene = that->greene * that->alphaf + data.greene * alf +
8359 DBL_EPSILON;
8360 that->bluef = that->bluef * that->alphaf + data.bluef * alf;
8361 that->bluee = that->bluee * that->alphaf + data.bluee * alf +
8362 DBL_EPSILON;
8363 }
8364
8365 /* Remove the alpha type and set the alpha (not in that order.) */
8366 that->alphaf = 1;
8367 that->alphae = 0;
8368 }
8369
8370 if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8371 that->colour_type = PNG_COLOR_TYPE_RGB;
8372 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
8373 that->colour_type = PNG_COLOR_TYPE_GRAY;
8374 /* PNG_COLOR_TYPE_PALETTE is not changed */
8375
8376 this->next->mod(this->next, that, pp, display);
8377}
8378
8379#define image_transform_png_set_background_add image_transform_default_add
8380
8381#undef data
8382IT(background);
8383#undef PT
8384#define PT ITSTRUCT(background)
8385#endif /* PNG_READ_BACKGROUND_SUPPORTED */
8386
8387/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
8388 * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
8389 *
8390 * Very difficult to validate this!
8391 */
8392/*NOTE: TBD NYI */
8393
8394/* The data layout transforms are handled by swapping our own channel data,
8395 * necessarily these need to happen at the end of the transform list because the
8396 * semantic of the channels changes after these are executed. Some of these,
8397 * like set_shift and set_packing, can't be done at present because they change
8398 * the layout of the data at the sub-sample level so sample() won't get the
8399 * right answer.
8400 */
8401/* png_set_invert_alpha */
8402#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
8403/* Invert the alpha channel
8404 *
8405 * png_set_invert_alpha(png_structrp png_ptr)
8406 */
8407static void
8408image_transform_png_set_invert_alpha_set(const image_transform *this,
8409 transform_display *that, png_structp pp, png_infop pi)
8410{
8411 png_set_invert_alpha(pp);
8412 this->next->set(this->next, that, pp, pi);
8413}
8414
8415static void
8416image_transform_png_set_invert_alpha_mod(const image_transform *this,
8417 image_pixel *that, png_const_structp pp,
8418 const transform_display *display)
8419{
8420 if (that->colour_type & 4)
8421 that->alpha_inverted = 1;
8422
8423 this->next->mod(this->next, that, pp, display);
8424}
8425
8426static int
8427image_transform_png_set_invert_alpha_add(image_transform *this,
8428 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8429{
8430 UNUSED(bit_depth)
8431
8432 this->next = *that;
8433 *that = this;
8434
8435 /* Only has an effect on pixels with alpha: */
8436 return (colour_type & 4) != 0;
8437}
8438
8439IT(invert_alpha);
8440#undef PT
8441#define PT ITSTRUCT(invert_alpha)
8442
8443#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
8444
8445/* png_set_bgr */
8446#ifdef PNG_READ_BGR_SUPPORTED
8447/* Swap R,G,B channels to order B,G,R.
8448 *
8449 * png_set_bgr(png_structrp png_ptr)
8450 *
8451 * This only has an effect on RGB and RGBA pixels.
8452 */
8453static void
8454image_transform_png_set_bgr_set(const image_transform *this,
8455 transform_display *that, png_structp pp, png_infop pi)
8456{
8457 png_set_bgr(pp);
8458 this->next->set(this->next, that, pp, pi);
8459}
8460
8461static void
8462image_transform_png_set_bgr_mod(const image_transform *this,
8463 image_pixel *that, png_const_structp pp,
8464 const transform_display *display)
8465{
8466 if (that->colour_type == PNG_COLOR_TYPE_RGB ||
8467 that->colour_type == PNG_COLOR_TYPE_RGBA)
8468 that->swap_rgb = 1;
8469
8470 this->next->mod(this->next, that, pp, display);
8471}
8472
8473static int
8474image_transform_png_set_bgr_add(image_transform *this,
8475 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8476{
8477 UNUSED(bit_depth)
8478
8479 this->next = *that;
8480 *that = this;
8481
8482 return colour_type == PNG_COLOR_TYPE_RGB ||
8483 colour_type == PNG_COLOR_TYPE_RGBA;
8484}
8485
8486IT(bgr);
8487#undef PT
8488#define PT ITSTRUCT(bgr)
8489
8490#endif /* PNG_READ_BGR_SUPPORTED */
8491
8492/* png_set_swap_alpha */
8493#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
8494/* Put the alpha channel first.
8495 *
8496 * png_set_swap_alpha(png_structrp png_ptr)
8497 *
8498 * This only has an effect on GA and RGBA pixels.
8499 */
8500static void
8501image_transform_png_set_swap_alpha_set(const image_transform *this,
8502 transform_display *that, png_structp pp, png_infop pi)
8503{
8504 png_set_swap_alpha(pp);
8505 this->next->set(this->next, that, pp, pi);
8506}
8507
8508static void
8509image_transform_png_set_swap_alpha_mod(const image_transform *this,
8510 image_pixel *that, png_const_structp pp,
8511 const transform_display *display)
8512{
8513 if (that->colour_type == PNG_COLOR_TYPE_GA ||
8514 that->colour_type == PNG_COLOR_TYPE_RGBA)
8515 that->alpha_first = 1;
8516
8517 this->next->mod(this->next, that, pp, display);
8518}
8519
8520static int
8521image_transform_png_set_swap_alpha_add(image_transform *this,
8522 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8523{
8524 UNUSED(bit_depth)
8525
8526 this->next = *that;
8527 *that = this;
8528
8529 return colour_type == PNG_COLOR_TYPE_GA ||
8530 colour_type == PNG_COLOR_TYPE_RGBA;
8531}
8532
8533IT(swap_alpha);
8534#undef PT
8535#define PT ITSTRUCT(swap_alpha)
8536
8537#endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */
8538
8539/* png_set_swap */
8540#ifdef PNG_READ_SWAP_SUPPORTED
8541/* Byte swap 16-bit components.
8542 *
8543 * png_set_swap(png_structrp png_ptr)
8544 */
8545static void
8546image_transform_png_set_swap_set(const image_transform *this,
8547 transform_display *that, png_structp pp, png_infop pi)
8548{
8549 png_set_swap(pp);
8550 this->next->set(this->next, that, pp, pi);
8551}
8552
8553static void
8554image_transform_png_set_swap_mod(const image_transform *this,
8555 image_pixel *that, png_const_structp pp,
8556 const transform_display *display)
8557{
8558 if (that->bit_depth == 16)
8559 that->swap16 = 1;
8560
8561 this->next->mod(this->next, that, pp, display);
8562}
8563
8564static int
8565image_transform_png_set_swap_add(image_transform *this,
8566 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8567{
8568 UNUSED(colour_type)
8569
8570 this->next = *that;
8571 *that = this;
8572
8573 return bit_depth == 16;
8574}
8575
8576IT(swap);
8577#undef PT
8578#define PT ITSTRUCT(swap)
8579
8580#endif /* PNG_READ_SWAP_SUPPORTED */
8581
8582#ifdef PNG_READ_FILLER_SUPPORTED
8583/* Add a filler byte to 8-bit Gray or 24-bit RGB images.
8584 *
8585 * png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags));
8586 *
8587 * Flags:
8588 *
8589 * PNG_FILLER_BEFORE
8590 * PNG_FILLER_AFTER
8591 */
8592#define data ITDATA(filler)
8593static struct
8594{
8595 png_uint_32 filler;
8596 int flags;
8597} data;
8598
8599static void
8600image_transform_png_set_filler_set(const image_transform *this,
8601 transform_display *that, png_structp pp, png_infop pi)
8602{
8603 /* Need a random choice for 'before' and 'after' as well as for the
8604 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8605 * will be used. At this point we don't know bit_depth.
8606 */
8607 data.filler = random_u32();
8608 data.flags = random_choice();
8609
8610 png_set_filler(pp, data.filler, data.flags);
8611
8612 /* The standard display handling stuff also needs to know that
8613 * there is a filler, so set that here.
8614 */
8615 that->this.filler = 1;
8616
8617 this->next->set(this->next, that, pp, pi);
8618}
8619
8620static void
8621image_transform_png_set_filler_mod(const image_transform *this,
8622 image_pixel *that, png_const_structp pp,
8623 const transform_display *display)
8624{
8625 if (that->bit_depth >= 8 &&
8626 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8627 that->colour_type == PNG_COLOR_TYPE_GRAY))
8628 {
8629 const unsigned int max = (1U << that->bit_depth)-1;
8630 that->alpha = data.filler & max;
8631 that->alphaf = ((double)that->alpha) / max;
8632 that->alphae = 0;
8633
8634 /* The filler has been stored in the alpha channel, we must record
8635 * that this has been done for the checking later on, the color
8636 * type is faked to have an alpha channel, but libpng won't report
8637 * this; the app has to know the extra channel is there and this
8638 * was recording in standard_display::filler above.
8639 */
8640 that->colour_type |= 4; /* alpha added */
8641 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8642 }
8643
8644 this->next->mod(this->next, that, pp, display);
8645}
8646
8647static int
8648image_transform_png_set_filler_add(image_transform *this,
8649 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8650{
8651 this->next = *that;
8652 *that = this;
8653
8654 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8655 colour_type == PNG_COLOR_TYPE_GRAY);
8656}
8657
8658#undef data
8659IT(filler);
8660#undef PT
8661#define PT ITSTRUCT(filler)
8662
8663/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
8664/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
8665#define data ITDATA(add_alpha)
8666static struct
8667{
8668 png_uint_32 filler;
8669 int flags;
8670} data;
8671
8672static void
8673image_transform_png_set_add_alpha_set(const image_transform *this,
8674 transform_display *that, png_structp pp, png_infop pi)
8675{
8676 /* Need a random choice for 'before' and 'after' as well as for the
8677 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8678 * will be used. At this point we don't know bit_depth.
8679 */
8680 data.filler = random_u32();
8681 data.flags = random_choice();
8682
8683 png_set_add_alpha(pp, data.filler, data.flags);
8684 this->next->set(this->next, that, pp, pi);
8685}
8686
8687static void
8688image_transform_png_set_add_alpha_mod(const image_transform *this,
8689 image_pixel *that, png_const_structp pp,
8690 const transform_display *display)
8691{
8692 if (that->bit_depth >= 8 &&
8693 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8694 that->colour_type == PNG_COLOR_TYPE_GRAY))
8695 {
8696 const unsigned int max = (1U << that->bit_depth)-1;
8697 that->alpha = data.filler & max;
8698 that->alphaf = ((double)that->alpha) / max;
8699 that->alphae = 0;
8700
8701 that->colour_type |= 4; /* alpha added */
8702 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8703 }
8704
8705 this->next->mod(this->next, that, pp, display);
8706}
8707
8708static int
8709image_transform_png_set_add_alpha_add(image_transform *this,
8710 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8711{
8712 this->next = *that;
8713 *that = this;
8714
8715 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8716 colour_type == PNG_COLOR_TYPE_GRAY);
8717}
8718
8719#undef data
8720IT(add_alpha);
8721#undef PT
8722#define PT ITSTRUCT(add_alpha)
8723
8724#endif /* PNG_READ_FILLER_SUPPORTED */
8725
8726/* png_set_packing */
8727#ifdef PNG_READ_PACK_SUPPORTED
8728/* Use 1 byte per pixel in 1, 2, or 4-bit depth files.
8729 *
8730 * png_set_packing(png_structrp png_ptr)
8731 *
8732 * This should only affect grayscale and palette images with less than 8 bits
8733 * per pixel.
8734 */
8735static void
8736image_transform_png_set_packing_set(const image_transform *this,
8737 transform_display *that, png_structp pp, png_infop pi)
8738{
8739 png_set_packing(pp);
8740 that->unpacked = 1;
8741 this->next->set(this->next, that, pp, pi);
8742}
8743
8744static void
8745image_transform_png_set_packing_mod(const image_transform *this,
8746 image_pixel *that, png_const_structp pp,
8747 const transform_display *display)
8748{
8749 /* The general expand case depends on what the colour type is,
8750 * low bit-depth pixel values are unpacked into bytes without
8751 * scaling, so sample_depth is not changed.
8752 */
8753 if (that->bit_depth < 8) /* grayscale or palette */
8754 that->bit_depth = 8;
8755
8756 this->next->mod(this->next, that, pp, display);
8757}
8758
8759static int
8760image_transform_png_set_packing_add(image_transform *this,
8761 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8762{
8763 UNUSED(colour_type)
8764
8765 this->next = *that;
8766 *that = this;
8767
8768 /* Nothing should happen unless the bit depth is less than 8: */
8769 return bit_depth < 8;
8770}
8771
8772IT(packing);
8773#undef PT
8774#define PT ITSTRUCT(packing)
8775
8776#endif /* PNG_READ_PACK_SUPPORTED */
8777
8778/* png_set_packswap */
8779#ifdef PNG_READ_PACKSWAP_SUPPORTED
8780/* Swap pixels packed into bytes; reverses the order on screen so that
8781 * the high order bits correspond to the rightmost pixels.
8782 *
8783 * png_set_packswap(png_structrp png_ptr)
8784 */
8785static void
8786image_transform_png_set_packswap_set(const image_transform *this,
8787 transform_display *that, png_structp pp, png_infop pi)
8788{
8789 png_set_packswap(pp);
8790 that->this.littleendian = 1;
8791 this->next->set(this->next, that, pp, pi);
8792}
8793
8794static void
8795image_transform_png_set_packswap_mod(const image_transform *this,
8796 image_pixel *that, png_const_structp pp,
8797 const transform_display *display)
8798{
8799 if (that->bit_depth < 8)
8800 that->littleendian = 1;
8801
8802 this->next->mod(this->next, that, pp, display);
8803}
8804
8805static int
8806image_transform_png_set_packswap_add(image_transform *this,
8807 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8808{
8809 UNUSED(colour_type)
8810
8811 this->next = *that;
8812 *that = this;
8813
8814 return bit_depth < 8;
8815}
8816
8817IT(packswap);
8818#undef PT
8819#define PT ITSTRUCT(packswap)
8820
8821#endif /* PNG_READ_PACKSWAP_SUPPORTED */
8822
8823
8824/* png_set_invert_mono */
8825#ifdef PNG_READ_INVERT_MONO_SUPPORTED
8826/* Invert the gray channel
8827 *
8828 * png_set_invert_mono(png_structrp png_ptr)
8829 */
8830static void
8831image_transform_png_set_invert_mono_set(const image_transform *this,
8832 transform_display *that, png_structp pp, png_infop pi)
8833{
8834 png_set_invert_mono(pp);
8835 this->next->set(this->next, that, pp, pi);
8836}
8837
8838static void
8839image_transform_png_set_invert_mono_mod(const image_transform *this,
8840 image_pixel *that, png_const_structp pp,
8841 const transform_display *display)
8842{
8843 if (that->colour_type & 4)
8844 that->mono_inverted = 1;
8845
8846 this->next->mod(this->next, that, pp, display);
8847}
8848
8849static int
8850image_transform_png_set_invert_mono_add(image_transform *this,
8851 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8852{
8853 UNUSED(bit_depth)
8854
8855 this->next = *that;
8856 *that = this;
8857
8858 /* Only has an effect on pixels with no colour: */
8859 return (colour_type & 2) == 0;
8860}
8861
8862IT(invert_mono);
8863#undef PT
8864#define PT ITSTRUCT(invert_mono)
8865
8866#endif /* PNG_READ_INVERT_MONO_SUPPORTED */
8867
8868#ifdef PNG_READ_SHIFT_SUPPORTED
8869/* png_set_shift(png_structp, png_const_color_8p true_bits)
8870 *
8871 * The output pixels will be shifted by the given true_bits
8872 * values.
8873 */
8874#define data ITDATA(shift)
8875static png_color_8 data;
8876
8877static void
8878image_transform_png_set_shift_set(const image_transform *this,
8879 transform_display *that, png_structp pp, png_infop pi)
8880{
8881 /* Get a random set of shifts. The shifts need to do something
8882 * to test the transform, so they are limited to the bit depth
8883 * of the input image. Notice that in the following the 'gray'
8884 * field is randomized independently. This acts as a check that
8885 * libpng does use the correct field.
8886 */
8887 const unsigned int depth = that->this.bit_depth;
8888
8889 data.red = (png_byte)/*SAFE*/(random_mod(depth)+1);
8890 data.green = (png_byte)/*SAFE*/(random_mod(depth)+1);
8891 data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1);
8892 data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1);
8893 data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1);
8894
8895 png_set_shift(pp, &data);
8896 this->next->set(this->next, that, pp, pi);
8897}
8898
8899static void
8900image_transform_png_set_shift_mod(const image_transform *this,
8901 image_pixel *that, png_const_structp pp,
8902 const transform_display *display)
8903{
8904 /* Copy the correct values into the sBIT fields, libpng does not do
8905 * anything to palette data:
8906 */
8907 if (that->colour_type != PNG_COLOR_TYPE_PALETTE)
8908 {
8909 that->sig_bits = 1;
8910
8911 /* The sBIT fields are reset to the values previously sent to
8912 * png_set_shift according to the colour type.
8913 * does.
8914 */
8915 if (that->colour_type & 2) /* RGB channels */
8916 {
8917 that->red_sBIT = data.red;
8918 that->green_sBIT = data.green;
8919 that->blue_sBIT = data.blue;
8920 }
8921
8922 else /* One grey channel */
8923 that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray;
8924
8925 that->alpha_sBIT = data.alpha;
8926 }
8927
8928 this->next->mod(this->next, that, pp, display);
8929}
8930
8931static int
8932image_transform_png_set_shift_add(image_transform *this,
8933 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8934{
8935 UNUSED(bit_depth)
8936
8937 this->next = *that;
8938 *that = this;
8939
8940 return colour_type != PNG_COLOR_TYPE_PALETTE;
8941}
8942
8943IT(shift);
8944#undef PT
8945#define PT ITSTRUCT(shift)
8946
8947#endif /* PNG_READ_SHIFT_SUPPORTED */
8948
8949#ifdef THIS_IS_THE_PROFORMA
8950static void
8951image_transform_png_set_@_set(const image_transform *this,
8952 transform_display *that, png_structp pp, png_infop pi)
8953{
8954 png_set_@(pp);
8955 this->next->set(this->next, that, pp, pi);
8956}
8957
8958static void
8959image_transform_png_set_@_mod(const image_transform *this,
8960 image_pixel *that, png_const_structp pp,
8961 const transform_display *display)
8962{
8963 this->next->mod(this->next, that, pp, display);
8964}
8965
8966static int
8967image_transform_png_set_@_add(image_transform *this,
8968 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8969{
8970 this->next = *that;
8971 *that = this;
8972
8973 return 1;
8974}
8975
8976IT(@);
8977#endif
8978
8979
8980/* This may just be 'end' if all the transforms are disabled! */
8981static image_transform *const image_transform_first = &PT;
8982
8983static void
8984transform_enable(const char *name)
8985{
8986 /* Everything starts out enabled, so if we see an 'enable' disabled
8987 * everything else the first time round.
8988 */
8989 static int all_disabled = 0;
8990 int found_it = 0;
8991 image_transform *list = image_transform_first;
8992
8993 while (list != &image_transform_end)
8994 {
8995 if (strcmp(list->name, name) == 0)
8996 {
8997 list->enable = 1;
8998 found_it = 1;
8999 }
9000 else if (!all_disabled)
9001 list->enable = 0;
9002
9003 list = list->list;
9004 }
9005
9006 all_disabled = 1;
9007
9008 if (!found_it)
9009 {
9010 fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
9011 name);
9012 exit(99);
9013 }
9014}
9015
9016static void
9017transform_disable(const char *name)
9018{
9019 image_transform *list = image_transform_first;
9020
9021 while (list != &image_transform_end)
9022 {
9023 if (strcmp(list->name, name) == 0)
9024 {
9025 list->enable = 0;
9026 return;
9027 }
9028
9029 list = list->list;
9030 }
9031
9032 fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
9033 name);
9034 exit(99);
9035}
9036
9037static void
9038image_transform_reset_count(void)
9039{
9040 image_transform *next = image_transform_first;
9041 int count = 0;
9042
9043 while (next != &image_transform_end)
9044 {
9045 next->local_use = 0;
9046 next->next = 0;
9047 next = next->list;
9048 ++count;
9049 }
9050
9051 /* This can only happen if we every have more than 32 transforms (excluding
9052 * the end) in the list.
9053 */
9054 if (count > 32) abort();
9055}
9056
9057static int
9058image_transform_test_counter(png_uint_32 counter, unsigned int max)
9059{
9060 /* Test the list to see if there is any point contining, given a current
9061 * counter and a 'max' value.
9062 */
9063 image_transform *next = image_transform_first;
9064
9065 while (next != &image_transform_end)
9066 {
9067 /* For max 0 or 1 continue until the counter overflows: */
9068 counter >>= 1;
9069
9070 /* Continue if any entry hasn't reacked the max. */
9071 if (max > 1 && next->local_use < max)
9072 return 1;
9073 next = next->list;
9074 }
9075
9076 return max <= 1 && counter == 0;
9077}
9078
9079static png_uint_32
9080image_transform_add(const image_transform **this, unsigned int max,
9081 png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
9082 png_byte colour_type, png_byte bit_depth)
9083{
9084 for (;;) /* until we manage to add something */
9085 {
9086 png_uint_32 mask;
9087 image_transform *list;
9088
9089 /* Find the next counter value, if the counter is zero this is the start
9090 * of the list. This routine always returns the current counter (not the
9091 * next) so it returns 0 at the end and expects 0 at the beginning.
9092 */
9093 if (counter == 0) /* first time */
9094 {
9095 image_transform_reset_count();
9096 if (max <= 1)
9097 counter = 1;
9098 else
9099 counter = random_32();
9100 }
9101 else /* advance the counter */
9102 {
9103 switch (max)
9104 {
9105 case 0: ++counter; break;
9106 case 1: counter <<= 1; break;
9107 default: counter = random_32(); break;
9108 }
9109 }
9110
9111 /* Now add all these items, if possible */
9112 *this = &image_transform_end;
9113 list = image_transform_first;
9114 mask = 1;
9115
9116 /* Go through the whole list adding anything that the counter selects: */
9117 while (list != &image_transform_end)
9118 {
9119 if ((counter & mask) != 0 && list->enable &&
9120 (max == 0 || list->local_use < max))
9121 {
9122 /* Candidate to add: */
9123 if (list->add(list, this, colour_type, bit_depth) || max == 0)
9124 {
9125 /* Added, so add to the name too. */
9126 *pos = safecat(name, sizeof_name, *pos, " +");
9127 *pos = safecat(name, sizeof_name, *pos, list->name);
9128 }
9129
9130 else
9131 {
9132 /* Not useful and max>0, so remove it from *this: */
9133 *this = list->next;
9134 list->next = 0;
9135
9136 /* And, since we know it isn't useful, stop it being added again
9137 * in this run:
9138 */
9139 list->local_use = max;
9140 }
9141 }
9142
9143 mask <<= 1;
9144 list = list->list;
9145 }
9146
9147 /* Now if anything was added we have something to do. */
9148 if (*this != &image_transform_end)
9149 return counter;
9150
9151 /* Nothing added, but was there anything in there to add? */
9152 if (!image_transform_test_counter(counter, max))
9153 return 0;
9154 }
9155}
9156
9157static void
9158perform_transform_test(png_modifier *pm)
9159{
9160 png_byte colour_type = 0;
9161 png_byte bit_depth = 0;
9162 unsigned int palette_number = 0;
9163
9164 while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg,
9165 pm->test_tRNS))
9166 {
9167 png_uint_32 counter = 0;
9168 size_t base_pos;
9169 char name[64];
9170
9171 base_pos = safecat(name, sizeof name, 0, "transform:");
9172
9173 for (;;)
9174 {
9175 size_t pos = base_pos;
9176 const image_transform *list = 0;
9177
9178 /* 'max' is currently hardwired to '1'; this should be settable on the
9179 * command line.
9180 */
9181 counter = image_transform_add(&list, 1/*max*/, counter,
9182 name, sizeof name, &pos, colour_type, bit_depth);
9183
9184 if (counter == 0)
9185 break;
9186
9187 /* The command line can change this to checking interlaced images. */
9188 do
9189 {
9190 pm->repeat = 0;
9191 transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
9192 pm->interlace_type, 0, 0, 0), list, name);
9193
9194 if (fail(pm))
9195 return;
9196 }
9197 while (pm->repeat);
9198 }
9199 }
9200}
9201#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
9202
9203/********************************* GAMMA TESTS ********************************/
9204#ifdef PNG_READ_GAMMA_SUPPORTED
9205/* Reader callbacks and implementations, where they differ from the standard
9206 * ones.
9207 */
9208typedef struct gamma_display
9209{
9210 standard_display this;
9211
9212 /* Parameters */
9213 png_modifier* pm;
9214 double file_gamma;
9215 double screen_gamma;
9216 double background_gamma;
9217 png_byte sbit;
9218 int threshold_test;
9219 int use_input_precision;
9220 int scale16;
9221 int expand16;
9222 int do_background;
9223 png_color_16 background_color;
9224
9225 /* Local variables */
9226 double maxerrout;
9227 double maxerrpc;
9228 double maxerrabs;
9229} gamma_display;
9230
9231#define ALPHA_MODE_OFFSET 4
9232
9233static void
9234gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
9235 double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
9236 int use_input_precision, int scale16, int expand16,
9237 int do_background, const png_color_16 *pointer_to_the_background_color,
9238 double background_gamma)
9239{
9240 /* Standard fields */
9241 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
9242 pm->use_update_info);
9243
9244 /* Parameter fields */
9245 dp->pm = pm;
9246 dp->file_gamma = file_gamma;
9247 dp->screen_gamma = screen_gamma;
9248 dp->background_gamma = background_gamma;
9249 dp->sbit = sbit;
9250 dp->threshold_test = threshold_test;
9251 dp->use_input_precision = use_input_precision;
9252 dp->scale16 = scale16;
9253 dp->expand16 = expand16;
9254 dp->do_background = do_background;
9255 if (do_background && pointer_to_the_background_color != 0)
9256 dp->background_color = *pointer_to_the_background_color;
9257 else
9258 memset(&dp->background_color, 0, sizeof dp->background_color);
9259
9260 /* Local variable fields */
9261 dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
9262}
9263
9264static void
9265gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
9266{
9267 /* Reuse the standard stuff as appropriate. */
9268 standard_info_part1(&dp->this, pp, pi);
9269
9270 /* If requested strip 16 to 8 bits - this is handled automagically below
9271 * because the output bit depth is read from the library. Note that there
9272 * are interactions with sBIT but, internally, libpng makes sbit at most
9273 * PNG_MAX_GAMMA_8 prior to 1.7 when doing the following.
9274 */
9275 if (dp->scale16)
9276# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
9277 png_set_scale_16(pp);
9278# else
9279 /* The following works both in 1.5.4 and earlier versions: */
9280# ifdef PNG_READ_16_TO_8_SUPPORTED
9281 png_set_strip_16(pp);
9282# else
9283 png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
9284# endif
9285# endif
9286
9287 if (dp->expand16)
9288# ifdef PNG_READ_EXPAND_16_SUPPORTED
9289 png_set_expand_16(pp);
9290# else
9291 png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
9292# endif
9293
9294 if (dp->do_background >= ALPHA_MODE_OFFSET)
9295 {
9296# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9297 {
9298 /* This tests the alpha mode handling, if supported. */
9299 int mode = dp->do_background - ALPHA_MODE_OFFSET;
9300
9301 /* The gamma value is the output gamma, and is in the standard,
9302 * non-inverted, represenation. It provides a default for the PNG file
9303 * gamma, but since the file has a gAMA chunk this does not matter.
9304 */
9305 const double sg = dp->screen_gamma;
9306# ifndef PNG_FLOATING_POINT_SUPPORTED
9307 const png_fixed_point g = fix(sg);
9308# endif
9309
9310# ifdef PNG_FLOATING_POINT_SUPPORTED
9311 png_set_alpha_mode(pp, mode, sg);
9312# else
9313 png_set_alpha_mode_fixed(pp, mode, g);
9314# endif
9315
9316 /* However, for the standard Porter-Duff algorithm the output defaults
9317 * to be linear, so if the test requires non-linear output it must be
9318 * corrected here.
9319 */
9320 if (mode == PNG_ALPHA_STANDARD && sg != 1)
9321 {
9322# ifdef PNG_FLOATING_POINT_SUPPORTED
9323 png_set_gamma(pp, sg, dp->file_gamma);
9324# else
9325 png_fixed_point f = fix(dp->file_gamma);
9326 png_set_gamma_fixed(pp, g, f);
9327# endif
9328 }
9329 }
9330# else
9331 png_error(pp, "alpha mode handling not supported");
9332# endif
9333 }
9334
9335 else
9336 {
9337 /* Set up gamma processing. */
9338# ifdef PNG_FLOATING_POINT_SUPPORTED
9339 png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
9340# else
9341 {
9342 png_fixed_point s = fix(dp->screen_gamma);
9343 png_fixed_point f = fix(dp->file_gamma);
9344 png_set_gamma_fixed(pp, s, f);
9345 }
9346# endif
9347
9348 if (dp->do_background)
9349 {
9350# ifdef PNG_READ_BACKGROUND_SUPPORTED
9351 /* NOTE: this assumes the caller provided the correct background gamma!
9352 */
9353 const double bg = dp->background_gamma;
9354# ifndef PNG_FLOATING_POINT_SUPPORTED
9355 const png_fixed_point g = fix(bg);
9356# endif
9357
9358# ifdef PNG_FLOATING_POINT_SUPPORTED
9359 png_set_background(pp, &dp->background_color, dp->do_background,
9360 0/*need_expand*/, bg);
9361# else
9362 png_set_background_fixed(pp, &dp->background_color,
9363 dp->do_background, 0/*need_expand*/, g);
9364# endif
9365# else
9366 png_error(pp, "png_set_background not supported");
9367# endif
9368 }
9369 }
9370
9371 {
9372 int i = dp->this.use_update_info;
9373 /* Always do one call, even if use_update_info is 0. */
9374 do
9375 png_read_update_info(pp, pi);
9376 while (--i > 0);
9377 }
9378
9379 /* Now we may get a different cbRow: */
9380 standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
9381}
9382
9383static void PNGCBAPI
9384gamma_info(png_structp pp, png_infop pi)
9385{
9386 gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
9387 pi);
9388}
9389
9390/* Validate a single component value - the routine gets the input and output
9391 * sample values as unscaled PNG component values along with a cache of all the
9392 * information required to validate the values.
9393 */
9394typedef struct validate_info
9395{
9396 png_const_structp pp;
9397 gamma_display *dp;
9398 png_byte sbit;
9399 int use_input_precision;
9400 int do_background;
9401 int scale16;
9402 unsigned int sbit_max;
9403 unsigned int isbit_shift;
9404 unsigned int outmax;
9405
9406 double gamma_correction; /* Overall correction required. */
9407 double file_inverse; /* Inverse of file gamma. */
9408 double screen_gamma;
9409 double screen_inverse; /* Inverse of screen gamma. */
9410
9411 double background_red; /* Linear background value, red or gray. */
9412 double background_green;
9413 double background_blue;
9414
9415 double maxabs;
9416 double maxpc;
9417 double maxcalc;
9418 double maxout;
9419 double maxout_total; /* Total including quantization error */
9420 double outlog;
9421 int outquant;
9422}
9423validate_info;
9424
9425static void
9426init_validate_info(validate_info *vi, gamma_display *dp, png_const_structp pp,
9427 int in_depth, int out_depth)
9428{
9429 const unsigned int outmax = (1U<<out_depth)-1;
9430
9431 vi->pp = pp;
9432 vi->dp = dp;
9433
9434 if (dp->sbit > 0 && dp->sbit < in_depth)
9435 {
9436 vi->sbit = dp->sbit;
9437 vi->isbit_shift = in_depth - dp->sbit;
9438 }
9439
9440 else
9441 {
9442 vi->sbit = (png_byte)in_depth;
9443 vi->isbit_shift = 0;
9444 }
9445
9446 vi->sbit_max = (1U << vi->sbit)-1;
9447
9448 /* This mimics the libpng threshold test, '0' is used to prevent gamma
9449 * correction in the validation test.
9450 */
9451 vi->screen_gamma = dp->screen_gamma;
9452 if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
9453 vi->screen_gamma = vi->screen_inverse = 0;
9454 else
9455 vi->screen_inverse = 1/vi->screen_gamma;
9456
9457 vi->use_input_precision = dp->use_input_precision;
9458 vi->outmax = outmax;
9459 vi->maxabs = abserr(dp->pm, in_depth, out_depth);
9460 vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
9461 vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
9462 vi->maxout = outerr(dp->pm, in_depth, out_depth);
9463 vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
9464 vi->maxout_total = vi->maxout + vi->outquant * .5;
9465 vi->outlog = outlog(dp->pm, in_depth, out_depth);
9466
9467 if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
9468 (dp->this.colour_type == 3 && dp->this.is_transparent) ||
9469 ((dp->this.colour_type == 0 || dp->this.colour_type == 2) &&
9470 dp->this.has_tRNS))
9471 {
9472 vi->do_background = dp->do_background;
9473
9474 if (vi->do_background != 0)
9475 {
9476 const double bg_inverse = 1/dp->background_gamma;
9477 double r, g, b;
9478
9479 /* Caller must at least put the gray value into the red channel */
9480 r = dp->background_color.red; r /= outmax;
9481 g = dp->background_color.green; g /= outmax;
9482 b = dp->background_color.blue; b /= outmax;
9483
9484# if 0
9485 /* libpng doesn't do this optimization, if we do pngvalid will fail.
9486 */
9487 if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
9488# endif
9489 {
9490 r = pow(r, bg_inverse);
9491 g = pow(g, bg_inverse);
9492 b = pow(b, bg_inverse);
9493 }
9494
9495 vi->background_red = r;
9496 vi->background_green = g;
9497 vi->background_blue = b;
9498 }
9499 }
9500 else /* Do not expect any background processing */
9501 vi->do_background = 0;
9502
9503 if (vi->do_background == 0)
9504 vi->background_red = vi->background_green = vi->background_blue = 0;
9505
9506 vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
9507 if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
9508 vi->gamma_correction = 0;
9509
9510 vi->file_inverse = 1/dp->file_gamma;
9511 if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
9512 vi->file_inverse = 0;
9513
9514 vi->scale16 = dp->scale16;
9515}
9516
9517/* This function handles composition of a single non-alpha component. The
9518 * argument is the input sample value, in the range 0..1, and the alpha value.
9519 * The result is the composed, linear, input sample. If alpha is less than zero
9520 * this is the alpha component and the function should not be called!
9521 */
9522static double
9523gamma_component_compose(int do_background, double input_sample, double alpha,
9524 double background, int *compose)
9525{
9526 switch (do_background)
9527 {
9528#ifdef PNG_READ_BACKGROUND_SUPPORTED
9529 case PNG_BACKGROUND_GAMMA_SCREEN:
9530 case PNG_BACKGROUND_GAMMA_FILE:
9531 case PNG_BACKGROUND_GAMMA_UNIQUE:
9532 /* Standard PNG background processing. */
9533 if (alpha < 1)
9534 {
9535 if (alpha > 0)
9536 {
9537 input_sample = input_sample * alpha + background * (1-alpha);
9538 if (compose != NULL)
9539 *compose = 1;
9540 }
9541
9542 else
9543 input_sample = background;
9544 }
9545 break;
9546#endif
9547
9548#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9549 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
9550 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
9551 /* The components are premultiplied in either case and the output is
9552 * gamma encoded (to get standard Porter-Duff we expect the output
9553 * gamma to be set to 1.0!)
9554 */
9555 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
9556 /* The optimization is that the partial-alpha entries are linear
9557 * while the opaque pixels are gamma encoded, but this only affects the
9558 * output encoding.
9559 */
9560 if (alpha < 1)
9561 {
9562 if (alpha > 0)
9563 {
9564 input_sample *= alpha;
9565 if (compose != NULL)
9566 *compose = 1;
9567 }
9568
9569 else
9570 input_sample = 0;
9571 }
9572 break;
9573#endif
9574
9575 default:
9576 /* Standard cases where no compositing is done (so the component
9577 * value is already correct.)
9578 */
9579 UNUSED(alpha)
9580 UNUSED(background)
9581 UNUSED(compose)
9582 break;
9583 }
9584
9585 return input_sample;
9586}
9587
9588/* This API returns the encoded *input* component, in the range 0..1 */
9589static double
9590gamma_component_validate(const char *name, const validate_info *vi,
9591 const unsigned int id, const unsigned int od,
9592 const double alpha /* <0 for the alpha channel itself */,
9593 const double background /* component background value */)
9594{
9595 const unsigned int isbit = id >> vi->isbit_shift;
9596 const unsigned int sbit_max = vi->sbit_max;
9597 const unsigned int outmax = vi->outmax;
9598 const int do_background = vi->do_background;
9599
9600 double i;
9601
9602 /* First check on the 'perfect' result obtained from the digitized input
9603 * value, id, and compare this against the actual digitized result, 'od'.
9604 * 'i' is the input result in the range 0..1:
9605 */
9606 i = isbit; i /= sbit_max;
9607
9608 /* Check for the fast route: if we don't do any background composition or if
9609 * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
9610 * just use the gamma_correction field to correct to the final output gamma.
9611 */
9612 if (alpha == 1 /* opaque pixel component */ || !do_background
9613#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9614 || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
9615#endif
9616 || (alpha < 0 /* alpha channel */
9617#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9618 && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
9619#endif
9620 ))
9621 {
9622 /* Then get the gamma corrected version of 'i' and compare to 'od', any
9623 * error less than .5 is insignificant - just quantization of the output
9624 * value to the nearest digital value (nevertheless the error is still
9625 * recorded - it's interesting ;-)
9626 */
9627 double encoded_sample = i;
9628 double encoded_error;
9629
9630 /* alpha less than 0 indicates the alpha channel, which is always linear
9631 */
9632 if (alpha >= 0 && vi->gamma_correction > 0)
9633 encoded_sample = pow(encoded_sample, vi->gamma_correction);
9634 encoded_sample *= outmax;
9635
9636 encoded_error = fabs(od-encoded_sample);
9637
9638 if (encoded_error > vi->dp->maxerrout)
9639 vi->dp->maxerrout = encoded_error;
9640
9641 if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
9642 return i;
9643 }
9644
9645 /* The slow route - attempt to do linear calculations. */
9646 /* There may be an error, or background processing is required, so calculate
9647 * the actual sample values - unencoded light intensity values. Note that in
9648 * practice these are not completely unencoded because they include a
9649 * 'viewing correction' to decrease or (normally) increase the perceptual
9650 * contrast of the image. There's nothing we can do about this - we don't
9651 * know what it is - so assume the unencoded value is perceptually linear.
9652 */
9653 {
9654 double input_sample = i; /* In range 0..1 */
9655 double output, error, encoded_sample, encoded_error;
9656 double es_lo, es_hi;
9657 int compose = 0; /* Set to one if composition done */
9658 int output_is_encoded; /* Set if encoded to screen gamma */
9659 int log_max_error = 1; /* Check maximum error values */
9660 png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
9661
9662 /* Convert to linear light (with the above caveat.) The alpha channel is
9663 * already linear.
9664 */
9665 if (alpha >= 0)
9666 {
9667 int tcompose;
9668
9669 if (vi->file_inverse > 0)
9670 input_sample = pow(input_sample, vi->file_inverse);
9671
9672 /* Handle the compose processing: */
9673 tcompose = 0;
9674 input_sample = gamma_component_compose(do_background, input_sample,
9675 alpha, background, &tcompose);
9676
9677 if (tcompose)
9678 compose = 1;
9679 }
9680
9681 /* And similarly for the output value, but we need to check the background
9682 * handling to linearize it correctly.
9683 */
9684 output = od;
9685 output /= outmax;
9686
9687 output_is_encoded = vi->screen_gamma > 0;
9688
9689 if (alpha < 0) /* The alpha channel */
9690 {
9691#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9692 if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
9693#endif
9694 {
9695 /* In all other cases the output alpha channel is linear already,
9696 * don't log errors here, they are much larger in linear data.
9697 */
9698 output_is_encoded = 0;
9699 log_max_error = 0;
9700 }
9701 }
9702
9703#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9704 else /* A component */
9705 {
9706 if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
9707 alpha < 1) /* the optimized case - linear output */
9708 {
9709 if (alpha > 0) log_max_error = 0;
9710 output_is_encoded = 0;
9711 }
9712 }
9713#endif
9714
9715 if (output_is_encoded)
9716 output = pow(output, vi->screen_gamma);
9717
9718 /* Calculate (or recalculate) the encoded_sample value and repeat the
9719 * check above (unnecessary if we took the fast route, but harmless.)
9720 */
9721 encoded_sample = input_sample;
9722 if (output_is_encoded)
9723 encoded_sample = pow(encoded_sample, vi->screen_inverse);
9724 encoded_sample *= outmax;
9725
9726 encoded_error = fabs(od-encoded_sample);
9727
9728 /* Don't log errors in the alpha channel, or the 'optimized' case,
9729 * neither are significant to the overall perception.
9730 */
9731 if (log_max_error && encoded_error > vi->dp->maxerrout)
9732 vi->dp->maxerrout = encoded_error;
9733
9734 if (encoded_error < vi->maxout_total)
9735 {
9736 if (encoded_error < vi->outlog)
9737 return i;
9738
9739 /* Test passed but error is bigger than the log limit, record why the
9740 * test passed:
9741 */
9742 pass = "less than maxout:\n";
9743 }
9744
9745 /* i: the original input value in the range 0..1
9746 *
9747 * pngvalid calculations:
9748 * input_sample: linear result; i linearized and composed, range 0..1
9749 * encoded_sample: encoded result; input_sample scaled to ouput bit depth
9750 *
9751 * libpng calculations:
9752 * output: linear result; od scaled to 0..1 and linearized
9753 * od: encoded result from libpng
9754 */
9755
9756 /* Now we have the numbers for real errors, both absolute values as as a
9757 * percentage of the correct value (output):
9758 */
9759 error = fabs(input_sample-output);
9760
9761 if (log_max_error && error > vi->dp->maxerrabs)
9762 vi->dp->maxerrabs = error;
9763
9764 /* The following is an attempt to ignore the tendency of quantization to
9765 * dominate the percentage errors for lower result values:
9766 */
9767 if (log_max_error && input_sample > .5)
9768 {
9769 double percentage_error = error/input_sample;
9770 if (percentage_error > vi->dp->maxerrpc)
9771 vi->dp->maxerrpc = percentage_error;
9772 }
9773
9774 /* Now calculate the digitization limits for 'encoded_sample' using the
9775 * 'max' values. Note that maxout is in the encoded space but maxpc and
9776 * maxabs are in linear light space.
9777 *
9778 * First find the maximum error in linear light space, range 0..1:
9779 */
9780 {
9781 double tmp = input_sample * vi->maxpc;
9782 if (tmp < vi->maxabs) tmp = vi->maxabs;
9783 /* If 'compose' is true the composition was done in linear space using
9784 * integer arithmetic. This introduces an extra error of +/- 0.5 (at
9785 * least) in the integer space used. 'maxcalc' records this, taking
9786 * into account the possibility that even for 16 bit output 8 bit space
9787 * may have been used.
9788 */
9789 if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
9790
9791 /* The 'maxout' value refers to the encoded result, to compare with
9792 * this encode input_sample adjusted by the maximum error (tmp) above.
9793 */
9794 es_lo = encoded_sample - vi->maxout;
9795
9796 if (es_lo > 0 && input_sample-tmp > 0)
9797 {
9798 double low_value = input_sample-tmp;
9799 if (output_is_encoded)
9800 low_value = pow(low_value, vi->screen_inverse);
9801 low_value *= outmax;
9802 if (low_value < es_lo) es_lo = low_value;
9803
9804 /* Quantize this appropriately: */
9805 es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
9806 }
9807
9808 else
9809 es_lo = 0;
9810
9811 es_hi = encoded_sample + vi->maxout;
9812
9813 if (es_hi < outmax && input_sample+tmp < 1)
9814 {
9815 double high_value = input_sample+tmp;
9816 if (output_is_encoded)
9817 high_value = pow(high_value, vi->screen_inverse);
9818 high_value *= outmax;
9819 if (high_value > es_hi) es_hi = high_value;
9820
9821 es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
9822 }
9823
9824 else
9825 es_hi = outmax;
9826 }
9827
9828 /* The primary test is that the final encoded value returned by the
9829 * library should be between the two limits (inclusive) that were
9830 * calculated above.
9831 */
9832 if (od >= es_lo && od <= es_hi)
9833 {
9834 /* The value passes, but we may need to log the information anyway. */
9835 if (encoded_error < vi->outlog)
9836 return i;
9837
9838 if (pass == 0)
9839 pass = "within digitization limits:\n";
9840 }
9841
9842 {
9843 /* There has been an error in processing, or we need to log this
9844 * value.
9845 */
9846 double is_lo, is_hi;
9847
9848 /* pass is set at this point if either of the tests above would have
9849 * passed. Don't do these additional tests here - just log the
9850 * original [es_lo..es_hi] values.
9851 */
9852 if (pass == 0 && vi->use_input_precision && vi->dp->sbit)
9853 {
9854 /* Ok, something is wrong - this actually happens in current libpng
9855 * 16-to-8 processing. Assume that the input value (id, adjusted
9856 * for sbit) can be anywhere between value-.5 and value+.5 - quite a
9857 * large range if sbit is low.
9858 *
9859 * NOTE: at present because the libpng gamma table stuff has been
9860 * changed to use a rounding algorithm to correct errors in 8-bit
9861 * calculations the precise sbit calculation (a shift) has been
9862 * lost. This can result in up to a +/-1 error in the presence of
9863 * an sbit less than the bit depth.
9864 */
9865# if PNG_LIBPNG_VER < 10700
9866# define SBIT_ERROR .5
9867# else
9868# define SBIT_ERROR 1.
9869# endif
9870 double tmp = (isbit - SBIT_ERROR)/sbit_max;
9871
9872 if (tmp <= 0)
9873 tmp = 0;
9874
9875 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9876 tmp = pow(tmp, vi->file_inverse);
9877
9878 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9879 NULL);
9880
9881 if (output_is_encoded && tmp > 0 && tmp < 1)
9882 tmp = pow(tmp, vi->screen_inverse);
9883
9884 is_lo = ceil(outmax * tmp - vi->maxout_total);
9885
9886 if (is_lo < 0)
9887 is_lo = 0;
9888
9889 tmp = (isbit + SBIT_ERROR)/sbit_max;
9890
9891 if (tmp >= 1)
9892 tmp = 1;
9893
9894 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9895 tmp = pow(tmp, vi->file_inverse);
9896
9897 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9898 NULL);
9899
9900 if (output_is_encoded && tmp > 0 && tmp < 1)
9901 tmp = pow(tmp, vi->screen_inverse);
9902
9903 is_hi = floor(outmax * tmp + vi->maxout_total);
9904
9905 if (is_hi > outmax)
9906 is_hi = outmax;
9907
9908 if (!(od < is_lo || od > is_hi))
9909 {
9910 if (encoded_error < vi->outlog)
9911 return i;
9912
9913 pass = "within input precision limits:\n";
9914 }
9915
9916 /* One last chance. If this is an alpha channel and the 16to8
9917 * option has been used and 'inaccurate' scaling is used then the
9918 * bit reduction is obtained by simply using the top 8 bits of the
9919 * value.
9920 *
9921 * This is only done for older libpng versions when the 'inaccurate'
9922 * (chop) method of scaling was used.
9923 */
9924# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
9925# if PNG_LIBPNG_VER < 10504
9926 /* This may be required for other components in the future,
9927 * but at present the presence of gamma correction effectively
9928 * prevents the errors in the component scaling (I don't quite
9929 * understand why, but since it's better this way I care not
9930 * to ask, JB 20110419.)
9931 */
9932 if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
9933 vi->sbit + vi->isbit_shift == 16)
9934 {
9935 tmp = ((id >> 8) - .5)/255;
9936
9937 if (tmp > 0)
9938 {
9939 is_lo = ceil(outmax * tmp - vi->maxout_total);
9940 if (is_lo < 0) is_lo = 0;
9941 }
9942
9943 else
9944 is_lo = 0;
9945
9946 tmp = ((id >> 8) + .5)/255;
9947
9948 if (tmp < 1)
9949 {
9950 is_hi = floor(outmax * tmp + vi->maxout_total);
9951 if (is_hi > outmax) is_hi = outmax;
9952 }
9953
9954 else
9955 is_hi = outmax;
9956
9957 if (!(od < is_lo || od > is_hi))
9958 {
9959 if (encoded_error < vi->outlog)
9960 return i;
9961
9962 pass = "within 8 bit limits:\n";
9963 }
9964 }
9965# endif
9966# endif
9967 }
9968 else /* !use_input_precision */
9969 is_lo = es_lo, is_hi = es_hi;
9970
9971 /* Attempt to output a meaningful error/warning message: the message
9972 * output depends on the background/composite operation being performed
9973 * because this changes what parameters were actually used above.
9974 */
9975 {
9976 size_t pos = 0;
9977 /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
9978 * places. Just use outmax to work out which.
9979 */
9980 int precision = (outmax >= 1000 ? 6 : 3);
9981 int use_input=1, use_background=0, do_compose=0;
9982 char msg[256];
9983
9984 if (pass != 0)
9985 pos = safecat(msg, sizeof msg, pos, "\n\t");
9986
9987 /* Set up the various flags, the output_is_encoded flag above
9988 * is also used below. do_compose is just a double check.
9989 */
9990 switch (do_background)
9991 {
9992# ifdef PNG_READ_BACKGROUND_SUPPORTED
9993 case PNG_BACKGROUND_GAMMA_SCREEN:
9994 case PNG_BACKGROUND_GAMMA_FILE:
9995 case PNG_BACKGROUND_GAMMA_UNIQUE:
9996 use_background = (alpha >= 0 && alpha < 1);
9997# endif
9998# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9999 /* FALLTHROUGH */
10000 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10001 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10002 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10003# endif /* ALPHA_MODE_SUPPORTED */
10004 do_compose = (alpha > 0 && alpha < 1);
10005 use_input = (alpha != 0);
10006 break;
10007
10008 default:
10009 break;
10010 }
10011
10012 /* Check the 'compose' flag */
10013 if (compose != do_compose)
10014 png_error(vi->pp, "internal error (compose)");
10015
10016 /* 'name' is the component name */
10017 pos = safecat(msg, sizeof msg, pos, name);
10018 pos = safecat(msg, sizeof msg, pos, "(");
10019 pos = safecatn(msg, sizeof msg, pos, id);
10020 if (use_input || pass != 0/*logging*/)
10021 {
10022 if (isbit != id)
10023 {
10024 /* sBIT has reduced the precision of the input: */
10025 pos = safecat(msg, sizeof msg, pos, ", sbit(");
10026 pos = safecatn(msg, sizeof msg, pos, vi->sbit);
10027 pos = safecat(msg, sizeof msg, pos, "): ");
10028 pos = safecatn(msg, sizeof msg, pos, isbit);
10029 }
10030 pos = safecat(msg, sizeof msg, pos, "/");
10031 /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
10032 pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
10033 }
10034 pos = safecat(msg, sizeof msg, pos, ")");
10035
10036 /* A component may have been multiplied (in linear space) by the
10037 * alpha value, 'compose' says whether this is relevant.
10038 */
10039 if (compose || pass != 0)
10040 {
10041 /* If any form of composition is being done report our
10042 * calculated linear value here (the code above doesn't record
10043 * the input value before composition is performed, so what
10044 * gets reported is the value after composition.)
10045 */
10046 if (use_input || pass != 0)
10047 {
10048 if (vi->file_inverse > 0)
10049 {
10050 pos = safecat(msg, sizeof msg, pos, "^");
10051 pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
10052 }
10053
10054 else
10055 pos = safecat(msg, sizeof msg, pos, "[linear]");
10056
10057 pos = safecat(msg, sizeof msg, pos, "*(alpha)");
10058 pos = safecatd(msg, sizeof msg, pos, alpha, precision);
10059 }
10060
10061 /* Now record the *linear* background value if it was used
10062 * (this function is not passed the original, non-linear,
10063 * value but it is contained in the test name.)
10064 */
10065 if (use_background)
10066 {
10067 pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
10068 pos = safecat(msg, sizeof msg, pos, "(background)");
10069 pos = safecatd(msg, sizeof msg, pos, background, precision);
10070 pos = safecat(msg, sizeof msg, pos, "*");
10071 pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
10072 }
10073 }
10074
10075 /* Report the calculated value (input_sample) and the linearized
10076 * libpng value (output) unless this is just a component gamma
10077 * correction.
10078 */
10079 if (compose || alpha < 0 || pass != 0)
10080 {
10081 pos = safecat(msg, sizeof msg, pos,
10082 pass != 0 ? " =\n\t" : " = ");
10083 pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
10084 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10085 pos = safecatd(msg, sizeof msg, pos, output, precision);
10086 pos = safecat(msg, sizeof msg, pos, ")");
10087
10088 /* Finally report the output gamma encoding, if any. */
10089 if (output_is_encoded)
10090 {
10091 pos = safecat(msg, sizeof msg, pos, " ^");
10092 pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
10093 pos = safecat(msg, sizeof msg, pos, "(to screen) =");
10094 }
10095
10096 else
10097 pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
10098 }
10099
10100 if ((!compose && alpha >= 0) || pass != 0)
10101 {
10102 if (pass != 0) /* logging */
10103 pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
10104
10105 /* This is the non-composition case, the internal linear
10106 * values are irrelevant (though the log below will reveal
10107 * them.) Output a much shorter warning/error message and report
10108 * the overall gamma correction.
10109 */
10110 if (vi->gamma_correction > 0)
10111 {
10112 pos = safecat(msg, sizeof msg, pos, " ^");
10113 pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
10114 pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
10115 }
10116
10117 else
10118 pos = safecat(msg, sizeof msg, pos,
10119 " [no gamma correction] =");
10120
10121 if (pass != 0)
10122 pos = safecat(msg, sizeof msg, pos, "]");
10123 }
10124
10125 /* This is our calculated encoded_sample which should (but does
10126 * not) match od:
10127 */
10128 pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
10129 pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
10130 pos = safecat(msg, sizeof msg, pos, " < ");
10131 pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
10132 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10133 pos = safecatn(msg, sizeof msg, pos, od);
10134 pos = safecat(msg, sizeof msg, pos, ")");
10135 pos = safecat(msg, sizeof msg, pos, "/");
10136 pos = safecatn(msg, sizeof msg, pos, outmax);
10137 pos = safecat(msg, sizeof msg, pos, " < ");
10138 pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
10139
10140 if (pass == 0) /* The error condition */
10141 {
10142# ifdef PNG_WARNINGS_SUPPORTED
10143 png_warning(vi->pp, msg);
10144# else
10145 store_warning(vi->pp, msg);
10146# endif
10147 }
10148
10149 else /* logging this value */
10150 store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
10151 }
10152 }
10153 }
10154
10155 return i;
10156}
10157
10158static void
10159gamma_image_validate(gamma_display *dp, png_const_structp pp,
10160 png_infop pi)
10161{
10162 /* Get some constants derived from the input and output file formats: */
10163 const png_store* const ps = dp->this.ps;
10164 const png_byte in_ct = dp->this.colour_type;
10165 const png_byte in_bd = dp->this.bit_depth;
10166 const png_uint_32 w = dp->this.w;
10167 const png_uint_32 h = dp->this.h;
10168 const size_t cbRow = dp->this.cbRow;
10169 const png_byte out_ct = png_get_color_type(pp, pi);
10170 const png_byte out_bd = png_get_bit_depth(pp, pi);
10171
10172 /* There are three sources of error, firstly the quantization in the
10173 * file encoding, determined by sbit and/or the file depth, secondly
10174 * the output (screen) gamma and thirdly the output file encoding.
10175 *
10176 * Since this API receives the screen and file gamma in double
10177 * precision it is possible to calculate an exact answer given an input
10178 * pixel value. Therefore we assume that the *input* value is exact -
10179 * sample/maxsample - calculate the corresponding gamma corrected
10180 * output to the limits of double precision arithmetic and compare with
10181 * what libpng returns.
10182 *
10183 * Since the library must quantize the output to 8 or 16 bits there is
10184 * a fundamental limit on the accuracy of the output of +/-.5 - this
10185 * quantization limit is included in addition to the other limits
10186 * specified by the paramaters to the API. (Effectively, add .5
10187 * everywhere.)
10188 *
10189 * The behavior of the 'sbit' paramter is defined by section 12.5
10190 * (sample depth scaling) of the PNG spec. That section forces the
10191 * decoder to assume that the PNG values have been scaled if sBIT is
10192 * present:
10193 *
10194 * png-sample = floor( input-sample * (max-out/max-in) + .5);
10195 *
10196 * This means that only a subset of the possible PNG values should
10197 * appear in the input. However, the spec allows the encoder to use a
10198 * variety of approximations to the above and doesn't require any
10199 * restriction of the values produced.
10200 *
10201 * Nevertheless the spec requires that the upper 'sBIT' bits of the
10202 * value stored in a PNG file be the original sample bits.
10203 * Consequently the code below simply scales the top sbit bits by
10204 * (1<<sbit)-1 to obtain an original sample value.
10205 *
10206 * Because there is limited precision in the input it is arguable that
10207 * an acceptable result is any valid result from input-.5 to input+.5.
10208 * The basic tests below do not do this, however if 'use_input_precision'
10209 * is set a subsequent test is performed above.
10210 */
10211 const unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
10212 int processing;
10213 png_uint_32 y;
10214 const store_palette_entry *in_palette = dp->this.palette;
10215 const int in_is_transparent = dp->this.is_transparent;
10216 int process_tRNS;
10217 int out_npalette = -1;
10218 int out_is_transparent = 0; /* Just refers to the palette case */
10219 store_palette out_palette;
10220 validate_info vi;
10221
10222 /* Check for row overwrite errors */
10223 store_image_check(dp->this.ps, pp, 0);
10224
10225 /* Supply the input and output sample depths here - 8 for an indexed image,
10226 * otherwise the bit depth.
10227 */
10228 init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
10229
10230 processing = (vi.gamma_correction > 0 && !dp->threshold_test)
10231 || in_bd != out_bd || in_ct != out_ct || vi.do_background;
10232 process_tRNS = dp->this.has_tRNS && vi.do_background;
10233
10234 /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
10235 * the palette there is no way of finding out, because libpng fails to
10236 * update the palette on png_read_update_info. Indeed, libpng doesn't
10237 * even do the required work until much later, when it doesn't have any
10238 * info pointer. Oops. For the moment 'processing' is turned off if
10239 * out_ct is palette.
10240 */
10241 if (in_ct == 3 && out_ct == 3)
10242 processing = 0;
10243
10244 if (processing && out_ct == 3)
10245 out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
10246
10247 for (y=0; y<h; ++y)
10248 {
10249 png_const_bytep pRow = store_image_row(ps, pp, 0, y);
10250 png_byte std[STANDARD_ROWMAX];
10251
10252 transform_row(pp, std, in_ct, in_bd, y);
10253
10254 if (processing)
10255 {
10256 unsigned int x;
10257
10258 for (x=0; x<w; ++x)
10259 {
10260 double alpha = 1; /* serves as a flag value */
10261
10262 /* Record the palette index for index images. */
10263 const unsigned int in_index =
10264 in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256;
10265 const unsigned int out_index =
10266 out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 0) : 256;
10267
10268 /* Handle input alpha - png_set_background will cause the output
10269 * alpha to disappear so there is nothing to check.
10270 */
10271 if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 ||
10272 (in_ct == 3 && in_is_transparent))
10273 {
10274 const unsigned int input_alpha = in_ct == 3 ?
10275 dp->this.palette[in_index].alpha :
10276 sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0);
10277
10278 unsigned int output_alpha = 65536 /* as a flag value */;
10279
10280 if (out_ct == 3)
10281 {
10282 if (out_is_transparent)
10283 output_alpha = out_palette[out_index].alpha;
10284 }
10285
10286 else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
10287 output_alpha = sample(pRow, out_ct, out_bd, x,
10288 samples_per_pixel, 0, 0);
10289
10290 if (output_alpha != 65536)
10291 alpha = gamma_component_validate("alpha", &vi, input_alpha,
10292 output_alpha, -1/*alpha*/, 0/*background*/);
10293
10294 else /* no alpha in output */
10295 {
10296 /* This is a copy of the calculation of 'i' above in order to
10297 * have the alpha value to use in the background calculation.
10298 */
10299 alpha = input_alpha >> vi.isbit_shift;
10300 alpha /= vi.sbit_max;
10301 }
10302 }
10303
10304 else if (process_tRNS)
10305 {
10306 /* alpha needs to be set appropriately for this pixel, it is
10307 * currently 1 and needs to be 0 for an input pixel which matches
10308 * the values in tRNS.
10309 */
10310 switch (in_ct)
10311 {
10312 case 0: /* gray */
10313 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10314 dp->this.transparent.red)
10315 alpha = 0;
10316 break;
10317
10318 case 2: /* RGB */
10319 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10320 dp->this.transparent.red &&
10321 sample(std, in_ct, in_bd, x, 1, 0, 0) ==
10322 dp->this.transparent.green &&
10323 sample(std, in_ct, in_bd, x, 2, 0, 0) ==
10324 dp->this.transparent.blue)
10325 alpha = 0;
10326 break;
10327
10328 default:
10329 break;
10330 }
10331 }
10332
10333 /* Handle grayscale or RGB components. */
10334 if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
10335 (void)gamma_component_validate("gray", &vi,
10336 sample(std, in_ct, in_bd, x, 0, 0, 0),
10337 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10338 alpha/*component*/, vi.background_red);
10339 else /* RGB or palette */
10340 {
10341 (void)gamma_component_validate("red", &vi,
10342 in_ct == 3 ? in_palette[in_index].red :
10343 sample(std, in_ct, in_bd, x, 0, 0, 0),
10344 out_ct == 3 ? out_palette[out_index].red :
10345 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10346 alpha/*component*/, vi.background_red);
10347
10348 (void)gamma_component_validate("green", &vi,
10349 in_ct == 3 ? in_palette[in_index].green :
10350 sample(std, in_ct, in_bd, x, 1, 0, 0),
10351 out_ct == 3 ? out_palette[out_index].green :
10352 sample(pRow, out_ct, out_bd, x, 1, 0, 0),
10353 alpha/*component*/, vi.background_green);
10354
10355 (void)gamma_component_validate("blue", &vi,
10356 in_ct == 3 ? in_palette[in_index].blue :
10357 sample(std, in_ct, in_bd, x, 2, 0, 0),
10358 out_ct == 3 ? out_palette[out_index].blue :
10359 sample(pRow, out_ct, out_bd, x, 2, 0, 0),
10360 alpha/*component*/, vi.background_blue);
10361 }
10362 }
10363 }
10364
10365 else if (memcmp(std, pRow, cbRow) != 0)
10366 {
10367 char msg[64];
10368
10369 /* No transform is expected on the threshold tests. */
10370 sprintf(msg, "gamma: below threshold row %lu changed",
10371 (unsigned long)y);
10372
10373 png_error(pp, msg);
10374 }
10375 } /* row (y) loop */
10376
10377 dp->this.ps->validated = 1;
10378}
10379
10380static void PNGCBAPI
10381gamma_end(png_structp ppIn, png_infop pi)
10382{
10383 png_const_structp pp = ppIn;
10384 gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
10385
10386 if (!dp->this.speed)
10387 gamma_image_validate(dp, pp, pi);
10388 else
10389 dp->this.ps->validated = 1;
10390}
10391
10392/* A single test run checking a gamma transformation.
10393 *
10394 * maxabs: maximum absolute error as a fraction
10395 * maxout: maximum output error in the output units
10396 * maxpc: maximum percentage error (as a percentage)
10397 */
10398static void
10399gamma_test(png_modifier *pmIn, const png_byte colour_typeIn,
10400 const png_byte bit_depthIn, const int palette_numberIn,
10401 const int interlace_typeIn,
10402 const double file_gammaIn, const double screen_gammaIn,
10403 const png_byte sbitIn, const int threshold_testIn,
10404 const char *name,
10405 const int use_input_precisionIn, const int scale16In,
10406 const int expand16In, const int do_backgroundIn,
10407 const png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
10408{
10409 gamma_display d;
10410 context(&pmIn->this, fault);
10411
10412 gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
10413 palette_numberIn, interlace_typeIn, 0, 0, 0),
10414 file_gammaIn, screen_gammaIn, sbitIn,
10415 threshold_testIn, use_input_precisionIn, scale16In,
10416 expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
10417
10418 Try
10419 {
10420 png_structp pp;
10421 png_infop pi;
10422 gama_modification gama_mod;
10423 srgb_modification srgb_mod;
10424 sbit_modification sbit_mod;
10425
10426 /* For the moment don't use the png_modifier support here. */
10427 d.pm->encoding_counter = 0;
10428 modifier_set_encoding(d.pm); /* Just resets everything */
10429 d.pm->current_gamma = d.file_gamma;
10430
10431 /* Make an appropriate modifier to set the PNG file gamma to the
10432 * given gamma value and the sBIT chunk to the given precision.
10433 */
10434 d.pm->modifications = NULL;
10435 gama_modification_init(&gama_mod, d.pm, d.file_gamma);
10436 srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
10437 if (d.sbit > 0)
10438 sbit_modification_init(&sbit_mod, d.pm, d.sbit);
10439
10440 modification_reset(d.pm->modifications);
10441
10442 /* Get a png_struct for reading the image. */
10443 pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
10444 standard_palette_init(&d.this);
10445
10446 /* Introduce the correct read function. */
10447 if (d.pm->this.progressive)
10448 {
10449 /* Share the row function with the standard implementation. */
10450 png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
10451 gamma_end);
10452
10453 /* Now feed data into the reader until we reach the end: */
10454 modifier_progressive_read(d.pm, pp, pi);
10455 }
10456 else
10457 {
10458 /* modifier_read expects a png_modifier* */
10459 png_set_read_fn(pp, d.pm, modifier_read);
10460
10461 /* Check the header values: */
10462 png_read_info(pp, pi);
10463
10464 /* Process the 'info' requirements. Only one image is generated */
10465 gamma_info_imp(&d, pp, pi);
10466
10467 sequential_row(&d.this, pp, pi, -1, 0);
10468
10469 if (!d.this.speed)
10470 gamma_image_validate(&d, pp, pi);
10471 else
10472 d.this.ps->validated = 1;
10473 }
10474
10475 modifier_reset(d.pm);
10476
10477 if (d.pm->log && !d.threshold_test && !d.this.speed)
10478 fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
10479 d.this.bit_depth, colour_types[d.this.colour_type], name,
10480 d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
10481
10482 /* Log the summary values too. */
10483 if (d.this.colour_type == 0 || d.this.colour_type == 4)
10484 {
10485 switch (d.this.bit_depth)
10486 {
10487 case 1:
10488 break;
10489
10490 case 2:
10491 if (d.maxerrout > d.pm->error_gray_2)
10492 d.pm->error_gray_2 = d.maxerrout;
10493
10494 break;
10495
10496 case 4:
10497 if (d.maxerrout > d.pm->error_gray_4)
10498 d.pm->error_gray_4 = d.maxerrout;
10499
10500 break;
10501
10502 case 8:
10503 if (d.maxerrout > d.pm->error_gray_8)
10504 d.pm->error_gray_8 = d.maxerrout;
10505
10506 break;
10507
10508 case 16:
10509 if (d.maxerrout > d.pm->error_gray_16)
10510 d.pm->error_gray_16 = d.maxerrout;
10511
10512 break;
10513
10514 default:
10515 png_error(pp, "bad bit depth (internal: 1)");
10516 }
10517 }
10518
10519 else if (d.this.colour_type == 2 || d.this.colour_type == 6)
10520 {
10521 switch (d.this.bit_depth)
10522 {
10523 case 8:
10524
10525 if (d.maxerrout > d.pm->error_color_8)
10526 d.pm->error_color_8 = d.maxerrout;
10527
10528 break;
10529
10530 case 16:
10531
10532 if (d.maxerrout > d.pm->error_color_16)
10533 d.pm->error_color_16 = d.maxerrout;
10534
10535 break;
10536
10537 default:
10538 png_error(pp, "bad bit depth (internal: 2)");
10539 }
10540 }
10541
10542 else if (d.this.colour_type == 3)
10543 {
10544 if (d.maxerrout > d.pm->error_indexed)
10545 d.pm->error_indexed = d.maxerrout;
10546 }
10547 }
10548
10549 Catch(fault)
10550 modifier_reset(voidcast(png_modifier*,(void*)fault));
10551}
10552
10553static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
10554 png_byte bit_depth, int interlace_type, double file_gamma,
10555 double screen_gamma)
10556{
10557 size_t pos = 0;
10558 char name[64];
10559 pos = safecat(name, sizeof name, pos, "threshold ");
10560 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10561 pos = safecat(name, sizeof name, pos, "/");
10562 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10563
10564 (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
10565 file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
10566 0 /*no input precision*/,
10567 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
10568 0 /*no background gamma*/);
10569}
10570
10571static void
10572perform_gamma_threshold_tests(png_modifier *pm)
10573{
10574 png_byte colour_type = 0;
10575 png_byte bit_depth = 0;
10576 unsigned int palette_number = 0;
10577
10578 /* Don't test more than one instance of each palette - it's pointless, in
10579 * fact this test is somewhat excessive since libpng doesn't make this
10580 * decision based on colour type or bit depth!
10581 *
10582 * CHANGED: now test two palettes and, as a side effect, images with and
10583 * without tRNS.
10584 */
10585 while (next_format(&colour_type, &bit_depth, &palette_number,
10586 pm->test_lbg_gamma_threshold, pm->test_tRNS))
10587 if (palette_number < 2)
10588 {
10589 double test_gamma = 1.0;
10590 while (test_gamma >= .4)
10591 {
10592 /* There's little point testing the interlacing vs non-interlacing,
10593 * but this can be set from the command line.
10594 */
10595 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10596 test_gamma, 1/test_gamma);
10597 test_gamma *= .95;
10598 }
10599
10600 /* And a special test for sRGB */
10601 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10602 .45455, 2.2);
10603
10604 if (fail(pm))
10605 return;
10606 }
10607}
10608
10609static void gamma_transform_test(png_modifier *pm,
10610 const png_byte colour_type, const png_byte bit_depth,
10611 const int palette_number,
10612 const int interlace_type, const double file_gamma,
10613 const double screen_gamma, const png_byte sbit,
10614 const int use_input_precision, const int scale16)
10615{
10616 size_t pos = 0;
10617 char name[64];
10618
10619 if (sbit != bit_depth && sbit != 0)
10620 {
10621 pos = safecat(name, sizeof name, pos, "sbit(");
10622 pos = safecatn(name, sizeof name, pos, sbit);
10623 pos = safecat(name, sizeof name, pos, ") ");
10624 }
10625
10626 else
10627 pos = safecat(name, sizeof name, pos, "gamma ");
10628
10629 if (scale16)
10630 pos = safecat(name, sizeof name, pos, "16to8 ");
10631
10632 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10633 pos = safecat(name, sizeof name, pos, "->");
10634 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10635
10636 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10637 file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
10638 scale16, pm->test_gamma_expand16, 0 , 0, 0);
10639}
10640
10641static void perform_gamma_transform_tests(png_modifier *pm)
10642{
10643 png_byte colour_type = 0;
10644 png_byte bit_depth = 0;
10645 unsigned int palette_number = 0;
10646
10647 while (next_format(&colour_type, &bit_depth, &palette_number,
10648 pm->test_lbg_gamma_transform, pm->test_tRNS))
10649 {
10650 unsigned int i, j;
10651
10652 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
10653 if (i != j)
10654 {
10655 gamma_transform_test(pm, colour_type, bit_depth, palette_number,
10656 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
10657 pm->use_input_precision, 0 /*do not scale16*/);
10658
10659 if (fail(pm))
10660 return;
10661 }
10662 }
10663}
10664
10665static void perform_gamma_sbit_tests(png_modifier *pm)
10666{
10667 png_byte sbit;
10668
10669 /* The only interesting cases are colour and grayscale, alpha is ignored here
10670 * for overall speed. Only bit depths where sbit is less than the bit depth
10671 * are tested.
10672 */
10673 for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
10674 {
10675 png_byte colour_type = 0, bit_depth = 0;
10676 unsigned int npalette = 0;
10677
10678 while (next_format(&colour_type, &bit_depth, &npalette,
10679 pm->test_lbg_gamma_sbit, pm->test_tRNS))
10680 if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
10681 ((colour_type == 3 && sbit < 8) ||
10682 (colour_type != 3 && sbit < bit_depth)))
10683 {
10684 unsigned int i;
10685
10686 for (i=0; i<pm->ngamma_tests; ++i)
10687 {
10688 unsigned int j;
10689
10690 for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
10691 {
10692 gamma_transform_test(pm, colour_type, bit_depth, npalette,
10693 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10694 sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
10695
10696 if (fail(pm))
10697 return;
10698 }
10699 }
10700 }
10701 }
10702}
10703
10704/* Note that this requires a 16 bit source image but produces 8 bit output, so
10705 * we only need the 16bit write support, but the 16 bit images are only
10706 * generated if DO_16BIT is defined.
10707 */
10708#ifdef DO_16BIT
10709static void perform_gamma_scale16_tests(png_modifier *pm)
10710{
10711# ifndef PNG_MAX_GAMMA_8
10712# define PNG_MAX_GAMMA_8 11
10713# endif
10714# if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700
10715# define SBIT_16_TO_8 PNG_MAX_GAMMA_8
10716# else
10717# define SBIT_16_TO_8 16
10718# endif
10719 /* Include the alpha cases here. Note that sbit matches the internal value
10720 * used by the library - otherwise we will get spurious errors from the
10721 * internal sbit style approximation.
10722 *
10723 * The threshold test is here because otherwise the 16 to 8 conversion will
10724 * proceed *without* gamma correction, and the tests above will fail (but not
10725 * by much) - this could be fixed, it only appears with the -g option.
10726 */
10727 unsigned int i, j;
10728 for (i=0; i<pm->ngamma_tests; ++i)
10729 {
10730 for (j=0; j<pm->ngamma_tests; ++j)
10731 {
10732 if (i != j &&
10733 fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
10734 {
10735 gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
10736 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10737 pm->use_input_precision_16to8, 1 /*scale16*/);
10738
10739 if (fail(pm))
10740 return;
10741
10742 gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
10743 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10744 pm->use_input_precision_16to8, 1 /*scale16*/);
10745
10746 if (fail(pm))
10747 return;
10748
10749 gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
10750 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10751 pm->use_input_precision_16to8, 1 /*scale16*/);
10752
10753 if (fail(pm))
10754 return;
10755
10756 gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
10757 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10758 pm->use_input_precision_16to8, 1 /*scale16*/);
10759
10760 if (fail(pm))
10761 return;
10762 }
10763 }
10764 }
10765}
10766#endif /* 16 to 8 bit conversion */
10767
10768#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
10769 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
10770static void gamma_composition_test(png_modifier *pm,
10771 const png_byte colour_type, const png_byte bit_depth,
10772 const int palette_number,
10773 const int interlace_type, const double file_gamma,
10774 const double screen_gamma,
10775 const int use_input_precision, const int do_background,
10776 const int expand_16)
10777{
10778 size_t pos = 0;
10779 png_const_charp base;
10780 double bg;
10781 char name[128];
10782 png_color_16 background;
10783
10784 /* Make up a name and get an appropriate background gamma value. */
10785 switch (do_background)
10786 {
10787 default:
10788 base = "";
10789 bg = 4; /* should not be used */
10790 break;
10791 case PNG_BACKGROUND_GAMMA_SCREEN:
10792 base = " bckg(Screen):";
10793 bg = 1/screen_gamma;
10794 break;
10795 case PNG_BACKGROUND_GAMMA_FILE:
10796 base = " bckg(File):";
10797 bg = file_gamma;
10798 break;
10799 case PNG_BACKGROUND_GAMMA_UNIQUE:
10800 base = " bckg(Unique):";
10801 /* This tests the handling of a unique value, the math is such that the
10802 * value tends to be <1, but is neither screen nor file (even if they
10803 * match!)
10804 */
10805 bg = (file_gamma + screen_gamma) / 3;
10806 break;
10807#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
10808 case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
10809 base = " alpha(PNG)";
10810 bg = 4; /* should not be used */
10811 break;
10812 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10813 base = " alpha(Porter-Duff)";
10814 bg = 4; /* should not be used */
10815 break;
10816 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10817 base = " alpha(Optimized)";
10818 bg = 4; /* should not be used */
10819 break;
10820 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10821 base = " alpha(Broken)";
10822 bg = 4; /* should not be used */
10823 break;
10824#endif
10825 }
10826
10827 /* Use random background values - the background is always presented in the
10828 * output space (8 or 16 bit components).
10829 */
10830 if (expand_16 || bit_depth == 16)
10831 {
10832 png_uint_32 r = random_32();
10833
10834 background.red = (png_uint_16)r;
10835 background.green = (png_uint_16)(r >> 16);
10836 r = random_32();
10837 background.blue = (png_uint_16)r;
10838 background.gray = (png_uint_16)(r >> 16);
10839
10840 /* In earlier libpng versions, those where DIGITIZE is set, any background
10841 * gamma correction in the expand16 case was done using 8-bit gamma
10842 * correction tables, resulting in larger errors. To cope with those
10843 * cases use a 16-bit background value which will handle this gamma
10844 * correction.
10845 */
10846# if DIGITIZE
10847 if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
10848 do_background == PNG_BACKGROUND_GAMMA_FILE) &&
10849 fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
10850 {
10851 /* The background values will be looked up in an 8-bit table to do
10852 * the gamma correction, so only select values which are an exact
10853 * match for the 8-bit table entries:
10854 */
10855 background.red = (png_uint_16)((background.red >> 8) * 257);
10856 background.green = (png_uint_16)((background.green >> 8) * 257);
10857 background.blue = (png_uint_16)((background.blue >> 8) * 257);
10858 background.gray = (png_uint_16)((background.gray >> 8) * 257);
10859 }
10860# endif
10861 }
10862
10863 else /* 8 bit colors */
10864 {
10865 png_uint_32 r = random_32();
10866
10867 background.red = (png_byte)r;
10868 background.green = (png_byte)(r >> 8);
10869 background.blue = (png_byte)(r >> 16);
10870 background.gray = (png_byte)(r >> 24);
10871 }
10872
10873 background.index = 193; /* rgb(193,193,193) to detect errors */
10874
10875 if (!(colour_type & PNG_COLOR_MASK_COLOR))
10876 {
10877 /* Because, currently, png_set_background is always called with
10878 * 'need_expand' false in this case and because the gamma test itself
10879 * doesn't cause an expand to 8-bit for lower bit depths the colour must
10880 * be reduced to the correct range.
10881 */
10882 if (bit_depth < 8)
10883 background.gray &= (png_uint_16)((1U << bit_depth)-1);
10884
10885 /* Grayscale input, we do not convert to RGB (TBD), so we must set the
10886 * background to gray - else libpng seems to fail.
10887 */
10888 background.red = background.green = background.blue = background.gray;
10889 }
10890
10891 pos = safecat(name, sizeof name, pos, "gamma ");
10892 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10893 pos = safecat(name, sizeof name, pos, "->");
10894 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10895
10896 pos = safecat(name, sizeof name, pos, base);
10897 if (do_background < ALPHA_MODE_OFFSET)
10898 {
10899 /* Include the background color and gamma in the name: */
10900 pos = safecat(name, sizeof name, pos, "(");
10901 /* This assumes no expand gray->rgb - the current code won't handle that!
10902 */
10903 if (colour_type & PNG_COLOR_MASK_COLOR)
10904 {
10905 pos = safecatn(name, sizeof name, pos, background.red);
10906 pos = safecat(name, sizeof name, pos, ",");
10907 pos = safecatn(name, sizeof name, pos, background.green);
10908 pos = safecat(name, sizeof name, pos, ",");
10909 pos = safecatn(name, sizeof name, pos, background.blue);
10910 }
10911 else
10912 pos = safecatn(name, sizeof name, pos, background.gray);
10913 pos = safecat(name, sizeof name, pos, ")^");
10914 pos = safecatd(name, sizeof name, pos, bg, 3);
10915 }
10916
10917 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10918 file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
10919 0/*strip 16*/, expand_16, do_background, &background, bg);
10920}
10921
10922
10923static void
10924perform_gamma_composition_tests(png_modifier *pm, int do_background,
10925 int expand_16)
10926{
10927 png_byte colour_type = 0;
10928 png_byte bit_depth = 0;
10929 unsigned int palette_number = 0;
10930
10931 /* Skip the non-alpha cases - there is no setting of a transparency colour at
10932 * present.
10933 *
10934 * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do,
10935 * however the palette case fails miserably so is commented out below.
10936 */
10937 while (next_format(&colour_type, &bit_depth, &palette_number,
10938 pm->test_lbg_gamma_composition, pm->test_tRNS))
10939 if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0
10940#if 0 /* TODO: FIXME */
10941 /*TODO: FIXME: this should work */
10942 || colour_type == 3
10943#endif
10944 || (colour_type != 3 && palette_number != 0))
10945 {
10946 unsigned int i, j;
10947
10948 /* Don't skip the i==j case here - it's relevant. */
10949 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
10950 {
10951 gamma_composition_test(pm, colour_type, bit_depth, palette_number,
10952 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10953 pm->use_input_precision, do_background, expand_16);
10954
10955 if (fail(pm))
10956 return;
10957 }
10958 }
10959}
10960#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
10961
10962static void
10963init_gamma_errors(png_modifier *pm)
10964{
10965 /* Use -1 to catch tests that were not actually run */
10966 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.;
10967 pm->error_color_8 = -1.;
10968 pm->error_indexed = -1.;
10969 pm->error_gray_16 = pm->error_color_16 = -1.;
10970}
10971
10972static void
10973print_one(const char *leader, double err)
10974{
10975 if (err != -1.)
10976 printf(" %s %.5f\n", leader, err);
10977}
10978
10979static void
10980summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth,
10981 int indexed)
10982{
10983 fflush(stderr);
10984
10985 if (who)
10986 printf("\nGamma correction with %s:\n", who);
10987
10988 else
10989 printf("\nBasic gamma correction:\n");
10990
10991 if (low_bit_depth)
10992 {
10993 print_one(" 2 bit gray: ", pm->error_gray_2);
10994 print_one(" 4 bit gray: ", pm->error_gray_4);
10995 print_one(" 8 bit gray: ", pm->error_gray_8);
10996 print_one(" 8 bit color:", pm->error_color_8);
10997 if (indexed)
10998 print_one(" indexed: ", pm->error_indexed);
10999 }
11000
11001 print_one("16 bit gray: ", pm->error_gray_16);
11002 print_one("16 bit color:", pm->error_color_16);
11003
11004 fflush(stdout);
11005}
11006
11007static void
11008perform_gamma_test(png_modifier *pm, int summary)
11009{
11010 /*TODO: remove this*/
11011 /* Save certain values for the temporary overrides below. */
11012 unsigned int calculations_use_input_precision =
11013 pm->calculations_use_input_precision;
11014# ifdef PNG_READ_BACKGROUND_SUPPORTED
11015 double maxout8 = pm->maxout8;
11016# endif
11017
11018 /* First some arbitrary no-transform tests: */
11019 if (!pm->this.speed && pm->test_gamma_threshold)
11020 {
11021 perform_gamma_threshold_tests(pm);
11022
11023 if (fail(pm))
11024 return;
11025 }
11026
11027 /* Now some real transforms. */
11028 if (pm->test_gamma_transform)
11029 {
11030 if (summary)
11031 {
11032 fflush(stderr);
11033 printf("Gamma correction error summary\n\n");
11034 printf("The printed value is the maximum error in the pixel values\n");
11035 printf("calculated by the libpng gamma correction code. The error\n");
11036 printf("is calculated as the difference between the output pixel\n");
11037 printf("value (always an integer) and the ideal value from the\n");
11038 printf("libpng specification (typically not an integer).\n\n");
11039
11040 printf("Expect this value to be less than .5 for 8 bit formats,\n");
11041 printf("less than 1 for formats with fewer than 8 bits and a small\n");
11042 printf("number (typically less than 5) for the 16 bit formats.\n");
11043 printf("For performance reasons the value for 16 bit formats\n");
11044 printf("increases when the image file includes an sBIT chunk.\n");
11045 fflush(stdout);
11046 }
11047
11048 init_gamma_errors(pm);
11049 /*TODO: remove this. Necessary because the current libpng
11050 * implementation works in 8 bits:
11051 */
11052 if (pm->test_gamma_expand16)
11053 pm->calculations_use_input_precision = 1;
11054 perform_gamma_transform_tests(pm);
11055 if (!calculations_use_input_precision)
11056 pm->calculations_use_input_precision = 0;
11057
11058 if (summary)
11059 summarize_gamma_errors(pm, 0/*who*/, 1/*low bit depth*/, 1/*indexed*/);
11060
11061 if (fail(pm))
11062 return;
11063 }
11064
11065 /* The sbit tests produce much larger errors: */
11066 if (pm->test_gamma_sbit)
11067 {
11068 init_gamma_errors(pm);
11069 perform_gamma_sbit_tests(pm);
11070
11071 if (summary)
11072 summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U, 1/*indexed*/);
11073
11074 if (fail(pm))
11075 return;
11076 }
11077
11078#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
11079 if (pm->test_gamma_scale16)
11080 {
11081 /* The 16 to 8 bit strip operations: */
11082 init_gamma_errors(pm);
11083 perform_gamma_scale16_tests(pm);
11084
11085 if (summary)
11086 {
11087 fflush(stderr);
11088 printf("\nGamma correction with 16 to 8 bit reduction:\n");
11089 printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
11090 printf(" 16 bit color: %.5f\n", pm->error_color_16);
11091 fflush(stdout);
11092 }
11093
11094 if (fail(pm))
11095 return;
11096 }
11097#endif
11098
11099#ifdef PNG_READ_BACKGROUND_SUPPORTED
11100 if (pm->test_gamma_background)
11101 {
11102 init_gamma_errors(pm);
11103
11104 /*TODO: remove this. Necessary because the current libpng
11105 * implementation works in 8 bits:
11106 */
11107 if (pm->test_gamma_expand16)
11108 {
11109 pm->calculations_use_input_precision = 1;
11110 pm->maxout8 = .499; /* because the 16 bit background is smashed */
11111 }
11112 perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
11113 pm->test_gamma_expand16);
11114 if (!calculations_use_input_precision)
11115 pm->calculations_use_input_precision = 0;
11116 pm->maxout8 = maxout8;
11117
11118 if (summary)
11119 summarize_gamma_errors(pm, "background", 1, 0/*indexed*/);
11120
11121 if (fail(pm))
11122 return;
11123 }
11124#endif
11125
11126#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
11127 if (pm->test_gamma_alpha_mode)
11128 {
11129 int do_background;
11130
11131 init_gamma_errors(pm);
11132
11133 /*TODO: remove this. Necessary because the current libpng
11134 * implementation works in 8 bits:
11135 */
11136 if (pm->test_gamma_expand16)
11137 pm->calculations_use_input_precision = 1;
11138 for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
11139 do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
11140 ++do_background)
11141 perform_gamma_composition_tests(pm, do_background,
11142 pm->test_gamma_expand16);
11143 if (!calculations_use_input_precision)
11144 pm->calculations_use_input_precision = 0;
11145
11146 if (summary)
11147 summarize_gamma_errors(pm, "alpha mode", 1, 0/*indexed*/);
11148
11149 if (fail(pm))
11150 return;
11151 }
11152#endif
11153}
11154#endif /* PNG_READ_GAMMA_SUPPORTED */
11155#endif /* PNG_READ_SUPPORTED */
11156
11157/* INTERLACE MACRO VALIDATION */
11158/* This is copied verbatim from the specification, it is simply the pass
11159 * number in which each pixel in each 8x8 tile appears. The array must
11160 * be indexed adam7[y][x] and notice that the pass numbers are based at
11161 * 1, not 0 - the base libpng uses.
11162 */
11163static const
11164png_byte adam7[8][8] =
11165{
11166 { 1,6,4,6,2,6,4,6 },
11167 { 7,7,7,7,7,7,7,7 },
11168 { 5,6,5,6,5,6,5,6 },
11169 { 7,7,7,7,7,7,7,7 },
11170 { 3,6,4,6,3,6,4,6 },
11171 { 7,7,7,7,7,7,7,7 },
11172 { 5,6,5,6,5,6,5,6 },
11173 { 7,7,7,7,7,7,7,7 }
11174};
11175
11176/* This routine validates all the interlace support macros in png.h for
11177 * a variety of valid PNG widths and heights. It uses a number of similarly
11178 * named internal routines that feed off the above array.
11179 */
11180static png_uint_32
11181png_pass_start_row(int pass)
11182{
11183 int x, y;
11184 ++pass;
11185 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11186 return y;
11187 return 0xf;
11188}
11189
11190static png_uint_32
11191png_pass_start_col(int pass)
11192{
11193 int x, y;
11194 ++pass;
11195 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11196 return x;
11197 return 0xf;
11198}
11199
11200static int
11201png_pass_row_shift(int pass)
11202{
11203 int x, y, base=(-1), inc=8;
11204 ++pass;
11205 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11206 {
11207 if (base == (-1))
11208 base = y;
11209 else if (base == y)
11210 {}
11211 else if (inc == y-base)
11212 base=y;
11213 else if (inc == 8)
11214 inc = y-base, base=y;
11215 else if (inc != y-base)
11216 return 0xff; /* error - more than one 'inc' value! */
11217 }
11218
11219 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11220
11221 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11222 switch (inc)
11223 {
11224case 2: return 1;
11225case 4: return 2;
11226case 8: return 3;
11227default: break;
11228 }
11229
11230 /* error - unrecognized 'inc' */
11231 return (inc << 8) + 0xfd;
11232}
11233
11234static int
11235png_pass_col_shift(int pass)
11236{
11237 int x, y, base=(-1), inc=8;
11238 ++pass;
11239 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11240 {
11241 if (base == (-1))
11242 base = x;
11243 else if (base == x)
11244 {}
11245 else if (inc == x-base)
11246 base=x;
11247 else if (inc == 8)
11248 inc = x-base, base=x;
11249 else if (inc != x-base)
11250 return 0xff; /* error - more than one 'inc' value! */
11251 }
11252
11253 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11254
11255 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11256 switch (inc)
11257 {
11258case 1: return 0; /* pass 7 has all the columns */
11259case 2: return 1;
11260case 4: return 2;
11261case 8: return 3;
11262default: break;
11263 }
11264
11265 /* error - unrecognized 'inc' */
11266 return (inc << 8) + 0xfd;
11267}
11268
11269static png_uint_32
11270png_row_from_pass_row(png_uint_32 yIn, int pass)
11271{
11272 /* By examination of the array: */
11273 switch (pass)
11274 {
11275case 0: return yIn * 8;
11276case 1: return yIn * 8;
11277case 2: return yIn * 8 + 4;
11278case 3: return yIn * 4;
11279case 4: return yIn * 4 + 2;
11280case 5: return yIn * 2;
11281case 6: return yIn * 2 + 1;
11282default: break;
11283 }
11284
11285 return 0xff; /* bad pass number */
11286}
11287
11288static png_uint_32
11289png_col_from_pass_col(png_uint_32 xIn, int pass)
11290{
11291 /* By examination of the array: */
11292 switch (pass)
11293 {
11294case 0: return xIn * 8;
11295case 1: return xIn * 8 + 4;
11296case 2: return xIn * 4;
11297case 3: return xIn * 4 + 2;
11298case 4: return xIn * 2;
11299case 5: return xIn * 2 + 1;
11300case 6: return xIn;
11301default: break;
11302 }
11303
11304 return 0xff; /* bad pass number */
11305}
11306
11307static int
11308png_row_in_interlace_pass(png_uint_32 y, int pass)
11309{
11310 /* Is row 'y' in pass 'pass'? */
11311 int x;
11312 y &= 7;
11313 ++pass;
11314 for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11315 return 1;
11316
11317 return 0;
11318}
11319
11320static int
11321png_col_in_interlace_pass(png_uint_32 x, int pass)
11322{
11323 /* Is column 'x' in pass 'pass'? */
11324 int y;
11325 x &= 7;
11326 ++pass;
11327 for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11328 return 1;
11329
11330 return 0;
11331}
11332
11333static png_uint_32
11334png_pass_rows(png_uint_32 height, int pass)
11335{
11336 png_uint_32 tiles = height>>3;
11337 png_uint_32 rows = 0;
11338 unsigned int x, y;
11339
11340 height &= 7;
11341 ++pass;
11342 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11343 {
11344 rows += tiles;
11345 if (y < height) ++rows;
11346 break; /* i.e. break the 'x', column, loop. */
11347 }
11348
11349 return rows;
11350}
11351
11352static png_uint_32
11353png_pass_cols(png_uint_32 width, int pass)
11354{
11355 png_uint_32 tiles = width>>3;
11356 png_uint_32 cols = 0;
11357 unsigned int x, y;
11358
11359 width &= 7;
11360 ++pass;
11361 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11362 {
11363 cols += tiles;
11364 if (x < width) ++cols;
11365 break; /* i.e. break the 'y', row, loop. */
11366 }
11367
11368 return cols;
11369}
11370
11371static void
11372perform_interlace_macro_validation(void)
11373{
11374 /* The macros to validate, first those that depend only on pass:
11375 *
11376 * PNG_PASS_START_ROW(pass)
11377 * PNG_PASS_START_COL(pass)
11378 * PNG_PASS_ROW_SHIFT(pass)
11379 * PNG_PASS_COL_SHIFT(pass)
11380 */
11381 int pass;
11382
11383 for (pass=0; pass<7; ++pass)
11384 {
11385 png_uint_32 m, f, v;
11386
11387 m = PNG_PASS_START_ROW(pass);
11388 f = png_pass_start_row(pass);
11389 if (m != f)
11390 {
11391 fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
11392 exit(99);
11393 }
11394
11395 m = PNG_PASS_START_COL(pass);
11396 f = png_pass_start_col(pass);
11397 if (m != f)
11398 {
11399 fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
11400 exit(99);
11401 }
11402
11403 m = PNG_PASS_ROW_SHIFT(pass);
11404 f = png_pass_row_shift(pass);
11405 if (m != f)
11406 {
11407 fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
11408 exit(99);
11409 }
11410
11411 m = PNG_PASS_COL_SHIFT(pass);
11412 f = png_pass_col_shift(pass);
11413 if (m != f)
11414 {
11415 fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
11416 exit(99);
11417 }
11418
11419 /* Macros that depend on the image or sub-image height too:
11420 *
11421 * PNG_PASS_ROWS(height, pass)
11422 * PNG_PASS_COLS(width, pass)
11423 * PNG_ROW_FROM_PASS_ROW(yIn, pass)
11424 * PNG_COL_FROM_PASS_COL(xIn, pass)
11425 * PNG_ROW_IN_INTERLACE_PASS(y, pass)
11426 * PNG_COL_IN_INTERLACE_PASS(x, pass)
11427 */
11428 for (v=0;;)
11429 {
11430 /* The first two tests overflow if the pass row or column is outside
11431 * the possible range for a 32-bit result. In fact the values should
11432 * never be outside the range for a 31-bit result, but checking for 32
11433 * bits here ensures that if an app uses a bogus pass row or column
11434 * (just so long as it fits in a 32 bit integer) it won't get a
11435 * possibly dangerous overflow.
11436 */
11437 /* First the base 0 stuff: */
11438 if (v < png_pass_rows(0xFFFFFFFFU, pass))
11439 {
11440 m = PNG_ROW_FROM_PASS_ROW(v, pass);
11441 f = png_row_from_pass_row(v, pass);
11442 if (m != f)
11443 {
11444 fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
11445 v, pass, m, f);
11446 exit(99);
11447 }
11448 }
11449
11450 if (v < png_pass_cols(0xFFFFFFFFU, pass))
11451 {
11452 m = PNG_COL_FROM_PASS_COL(v, pass);
11453 f = png_col_from_pass_col(v, pass);
11454 if (m != f)
11455 {
11456 fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
11457 v, pass, m, f);
11458 exit(99);
11459 }
11460 }
11461
11462 m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
11463 f = png_row_in_interlace_pass(v, pass);
11464 if (m != f)
11465 {
11466 fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11467 v, pass, m, f);
11468 exit(99);
11469 }
11470
11471 m = PNG_COL_IN_INTERLACE_PASS(v, pass);
11472 f = png_col_in_interlace_pass(v, pass);
11473 if (m != f)
11474 {
11475 fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11476 v, pass, m, f);
11477 exit(99);
11478 }
11479
11480 /* Then the base 1 stuff: */
11481 ++v;
11482 m = PNG_PASS_ROWS(v, pass);
11483 f = png_pass_rows(v, pass);
11484 if (m != f)
11485 {
11486 fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
11487 v, pass, m, f);
11488 exit(99);
11489 }
11490
11491 m = PNG_PASS_COLS(v, pass);
11492 f = png_pass_cols(v, pass);
11493 if (m != f)
11494 {
11495 fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
11496 v, pass, m, f);
11497 exit(99);
11498 }
11499
11500 /* Move to the next v - the stepping algorithm starts skipping
11501 * values above 1024.
11502 */
11503 if (v > 1024)
11504 {
11505 if (v == PNG_UINT_31_MAX)
11506 break;
11507
11508 v = (v << 1) ^ v;
11509 if (v >= PNG_UINT_31_MAX)
11510 v = PNG_UINT_31_MAX-1;
11511 }
11512 }
11513 }
11514}
11515
11516/* Test color encodings. These values are back-calculated from the published
11517 * chromaticities. The values are accurate to about 14 decimal places; 15 are
11518 * given. These values are much more accurate than the ones given in the spec,
11519 * which typically don't exceed 4 decimal places. This allows testing of the
11520 * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
11521 * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
11522 * more.)
11523 *
11524 * The png_modifier code assumes that encodings[0] is sRGB and treats it
11525 * specially: do not change the first entry in this list!
11526 */
11527static const color_encoding test_encodings[] =
11528{
11529/* sRGB: must be first in this list! */
11530/*gamma:*/ { 1/2.2,
11531/*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
11532/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
11533/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
11534/* Kodak ProPhoto (wide gamut) */
11535/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
11536/*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
11537/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
11538/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
11539/* Adobe RGB (1998) */
11540/*gamma:*/ { 1/(2+51./256),
11541/*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
11542/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
11543/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
11544/* Adobe Wide Gamut RGB */
11545/*gamma:*/ { 1/(2+51./256),
11546/*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
11547/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
11548/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
11549/* Fake encoding which selects just the green channel */
11550/*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
11551/*red: */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
11552/*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
11553/*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
11554};
11555
11556/* signal handler
11557 *
11558 * This attempts to trap signals and escape without crashing. It needs a
11559 * context pointer so that it can throw an exception (call longjmp) to recover
11560 * from the condition; this is handled by making the png_modifier used by 'main'
11561 * into a global variable.
11562 */
11563static png_modifier pm;
11564
11565static void signal_handler(int signum)
11566{
11567
11568 size_t pos = 0;
11569 char msg[64];
11570
11571 pos = safecat(msg, sizeof msg, pos, "caught signal: ");
11572
11573 switch (signum)
11574 {
11575 case SIGABRT:
11576 pos = safecat(msg, sizeof msg, pos, "abort");
11577 break;
11578
11579 case SIGFPE:
11580 pos = safecat(msg, sizeof msg, pos, "floating point exception");
11581 break;
11582
11583 case SIGILL:
11584 pos = safecat(msg, sizeof msg, pos, "illegal instruction");
11585 break;
11586
11587 case SIGINT:
11588 pos = safecat(msg, sizeof msg, pos, "interrupt");
11589 break;
11590
11591 case SIGSEGV:
11592 pos = safecat(msg, sizeof msg, pos, "invalid memory access");
11593 break;
11594
11595 case SIGTERM:
11596 pos = safecat(msg, sizeof msg, pos, "termination request");
11597 break;
11598
11599 default:
11600 pos = safecat(msg, sizeof msg, pos, "unknown ");
11601 pos = safecatn(msg, sizeof msg, pos, signum);
11602 break;
11603 }
11604
11605 store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
11606
11607 /* And finally throw an exception so we can keep going, unless this is
11608 * SIGTERM in which case stop now.
11609 */
11610 if (signum != SIGTERM)
11611 {
11612 struct exception_context *the_exception_context =
11613 &pm.this.exception_context;
11614
11615 Throw &pm.this;
11616 }
11617
11618 else
11619 exit(1);
11620}
11621
11622/* main program */
11623int main(int argc, char **argv)
11624{
11625 int summary = 1; /* Print the error summary at the end */
11626 int memstats = 0; /* Print memory statistics at the end */
11627
11628 /* Create the given output file on success: */
11629 const char *touch = NULL;
11630
11631 /* This is an array of standard gamma values (believe it or not I've seen
11632 * every one of these mentioned somewhere.)
11633 *
11634 * In the following list the most useful values are first!
11635 */
11636 static double
11637 gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
11638
11639 /* This records the command and arguments: */
11640 size_t cp = 0;
11641 char command[1024];
11642
11643 anon_context(&pm.this);
11644
11645 gnu_volatile(summary)
11646 gnu_volatile(memstats)
11647 gnu_volatile(touch)
11648
11649 /* Add appropriate signal handlers, just the ANSI specified ones: */
11650 signal(SIGABRT, signal_handler);
11651 signal(SIGFPE, signal_handler);
11652 signal(SIGILL, signal_handler);
11653 signal(SIGINT, signal_handler);
11654 signal(SIGSEGV, signal_handler);
11655 signal(SIGTERM, signal_handler);
11656
11657#ifdef HAVE_FEENABLEEXCEPT
11658 /* Only required to enable FP exceptions on platforms where they start off
11659 * disabled; this is not necessary but if it is not done pngvalid will likely
11660 * end up ignoring FP conditions that other platforms fault.
11661 */
11662 feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
11663#endif
11664
11665 modifier_init(&pm);
11666
11667 /* Preallocate the image buffer, because we know how big it needs to be,
11668 * note that, for testing purposes, it is deliberately mis-aligned by tag
11669 * bytes either side. All rows have an additional five bytes of padding for
11670 * overwrite checking.
11671 */
11672 store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
11673
11674 /* Don't give argv[0], it's normally some horrible libtool string: */
11675 cp = safecat(command, sizeof command, cp, "pngvalid");
11676
11677 /* Default to error on warning: */
11678 pm.this.treat_warnings_as_errors = 1;
11679
11680 /* Default assume_16_bit_calculations appropriately; this tells the checking
11681 * code that 16-bit arithmetic is used for 8-bit samples when it would make a
11682 * difference.
11683 */
11684 pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700;
11685
11686 /* Currently 16 bit expansion happens at the end of the pipeline, so the
11687 * calculations are done in the input bit depth not the output.
11688 *
11689 * TODO: fix this
11690 */
11691 pm.calculations_use_input_precision = 1U;
11692
11693 /* Store the test gammas */
11694 pm.gammas = gammas;
11695 pm.ngammas = ARRAY_SIZE(gammas);
11696 pm.ngamma_tests = 0; /* default to off */
11697
11698 /* Low bit depth gray images don't do well in the gamma tests, until
11699 * this is fixed turn them off for some gamma cases:
11700 */
11701# ifdef PNG_WRITE_tRNS_SUPPORTED
11702 pm.test_tRNS = 1;
11703# endif
11704 pm.test_lbg = PNG_LIBPNG_VER >= 10600;
11705 pm.test_lbg_gamma_threshold = 1;
11706 pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
11707 pm.test_lbg_gamma_sbit = 1;
11708 pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700;
11709
11710 /* And the test encodings */
11711 pm.encodings = test_encodings;
11712 pm.nencodings = ARRAY_SIZE(test_encodings);
11713
11714# if PNG_LIBPNG_VER < 10700
11715 pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
11716# else
11717 pm.sbitlow = 1U;
11718# endif
11719
11720 /* The following allows results to pass if they correspond to anything in the
11721 * transformed range [input-.5,input+.5]; this is is required because of the
11722 * way libpng treates the 16_TO_8 flag when building the gamma tables in
11723 * releases up to 1.6.0.
11724 *
11725 * TODO: review this
11726 */
11727 pm.use_input_precision_16to8 = 1U;
11728 pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */
11729
11730 /* Some default values (set the behavior for 'make check' here).
11731 * These values simply control the maximum error permitted in the gamma
11732 * transformations. The practial limits for human perception are described
11733 * below (the setting for maxpc16), however for 8 bit encodings it isn't
11734 * possible to meet the accepted capabilities of human vision - i.e. 8 bit
11735 * images can never be good enough, regardless of encoding.
11736 */
11737 pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
11738 pm.maxabs8 = .00005; /* 1/20000 */
11739 pm.maxcalc8 = 1./255; /* +/-1 in 8 bits for compose errors */
11740 pm.maxpc8 = .499; /* I.e., .499% fractional error */
11741 pm.maxout16 = .499; /* Error in *encoded* value */
11742 pm.maxabs16 = .00005;/* 1/20000 */
11743 pm.maxcalc16 =1./65535;/* +/-1 in 16 bits for compose errors */
11744# if PNG_LIBPNG_VER < 10700
11745 pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1);
11746# else
11747 pm.maxcalcG = 1./((1<<16)-1);
11748# endif
11749
11750 /* NOTE: this is a reasonable perceptual limit. We assume that humans can
11751 * perceive light level differences of 1% over a 100:1 range, so we need to
11752 * maintain 1 in 10000 accuracy (in linear light space), which is what the
11753 * following guarantees. It also allows significantly higher errors at
11754 * higher 16 bit values, which is important for performance. The actual
11755 * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
11756 * this is only allowed for values >38149 by the following:
11757 */
11758 pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
11759
11760 /* Now parse the command line options. */
11761 while (--argc >= 1)
11762 {
11763 int catmore = 0; /* Set if the argument has an argument. */
11764
11765 /* Record each argument for posterity: */
11766 cp = safecat(command, sizeof command, cp, " ");
11767 cp = safecat(command, sizeof command, cp, *++argv);
11768
11769 if (strcmp(*argv, "-v") == 0)
11770 pm.this.verbose = 1;
11771
11772 else if (strcmp(*argv, "-l") == 0)
11773 pm.log = 1;
11774
11775 else if (strcmp(*argv, "-q") == 0)
11776 summary = pm.this.verbose = pm.log = 0;
11777
11778 else if (strcmp(*argv, "-w") == 0 ||
11779 strcmp(*argv, "--strict") == 0)
11780 pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */
11781
11782 else if (strcmp(*argv, "--nostrict") == 0)
11783 pm.this.treat_warnings_as_errors = 0;
11784
11785 else if (strcmp(*argv, "--speed") == 0)
11786 pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
11787 summary = 0;
11788
11789 else if (strcmp(*argv, "--memory") == 0)
11790 memstats = 1;
11791
11792 else if (strcmp(*argv, "--size") == 0)
11793 pm.test_size = 1;
11794
11795 else if (strcmp(*argv, "--nosize") == 0)
11796 pm.test_size = 0;
11797
11798 else if (strcmp(*argv, "--standard") == 0)
11799 pm.test_standard = 1;
11800
11801 else if (strcmp(*argv, "--nostandard") == 0)
11802 pm.test_standard = 0;
11803
11804 else if (strcmp(*argv, "--transform") == 0)
11805 pm.test_transform = 1;
11806
11807 else if (strcmp(*argv, "--notransform") == 0)
11808 pm.test_transform = 0;
11809
11810#ifdef PNG_READ_TRANSFORMS_SUPPORTED
11811 else if (strncmp(*argv, "--transform-disable=",
11812 sizeof "--transform-disable") == 0)
11813 {
11814 pm.test_transform = 1;
11815 transform_disable(*argv + sizeof "--transform-disable");
11816 }
11817
11818 else if (strncmp(*argv, "--transform-enable=",
11819 sizeof "--transform-enable") == 0)
11820 {
11821 pm.test_transform = 1;
11822 transform_enable(*argv + sizeof "--transform-enable");
11823 }
11824#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
11825
11826 else if (strcmp(*argv, "--gamma") == 0)
11827 {
11828 /* Just do two gamma tests here (2.2 and linear) for speed: */
11829 pm.ngamma_tests = 2U;
11830 pm.test_gamma_threshold = 1;
11831 pm.test_gamma_transform = 1;
11832 pm.test_gamma_sbit = 1;
11833 pm.test_gamma_scale16 = 1;
11834 pm.test_gamma_background = 1; /* composition */
11835 pm.test_gamma_alpha_mode = 1;
11836 }
11837
11838 else if (strcmp(*argv, "--nogamma") == 0)
11839 pm.ngamma_tests = 0;
11840
11841 else if (strcmp(*argv, "--gamma-threshold") == 0)
11842 pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
11843
11844 else if (strcmp(*argv, "--nogamma-threshold") == 0)
11845 pm.test_gamma_threshold = 0;
11846
11847 else if (strcmp(*argv, "--gamma-transform") == 0)
11848 pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
11849
11850 else if (strcmp(*argv, "--nogamma-transform") == 0)
11851 pm.test_gamma_transform = 0;
11852
11853 else if (strcmp(*argv, "--gamma-sbit") == 0)
11854 pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
11855
11856 else if (strcmp(*argv, "--nogamma-sbit") == 0)
11857 pm.test_gamma_sbit = 0;
11858
11859 else if (strcmp(*argv, "--gamma-16-to-8") == 0)
11860 pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
11861
11862 else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
11863 pm.test_gamma_scale16 = 0;
11864
11865 else if (strcmp(*argv, "--gamma-background") == 0)
11866 pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
11867
11868 else if (strcmp(*argv, "--nogamma-background") == 0)
11869 pm.test_gamma_background = 0;
11870
11871 else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
11872 pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
11873
11874 else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
11875 pm.test_gamma_alpha_mode = 0;
11876
11877 else if (strcmp(*argv, "--expand16") == 0)
11878 pm.test_gamma_expand16 = 1;
11879
11880 else if (strcmp(*argv, "--noexpand16") == 0)
11881 pm.test_gamma_expand16 = 0;
11882
11883 else if (strcmp(*argv, "--low-depth-gray") == 0)
11884 pm.test_lbg = pm.test_lbg_gamma_threshold =
11885 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11886 pm.test_lbg_gamma_composition = 1;
11887
11888 else if (strcmp(*argv, "--nolow-depth-gray") == 0)
11889 pm.test_lbg = pm.test_lbg_gamma_threshold =
11890 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11891 pm.test_lbg_gamma_composition = 0;
11892
11893# ifdef PNG_WRITE_tRNS_SUPPORTED
11894 else if (strcmp(*argv, "--tRNS") == 0)
11895 pm.test_tRNS = 1;
11896# endif
11897
11898 else if (strcmp(*argv, "--notRNS") == 0)
11899 pm.test_tRNS = 0;
11900
11901 else if (strcmp(*argv, "--more-gammas") == 0)
11902 pm.ngamma_tests = 3U;
11903
11904 else if (strcmp(*argv, "--all-gammas") == 0)
11905 pm.ngamma_tests = pm.ngammas;
11906
11907 else if (strcmp(*argv, "--progressive-read") == 0)
11908 pm.this.progressive = 1;
11909
11910 else if (strcmp(*argv, "--use-update-info") == 0)
11911 ++pm.use_update_info; /* Can call multiple times */
11912
11913 else if (strcmp(*argv, "--interlace") == 0)
11914 {
11915# if CAN_WRITE_INTERLACE
11916 pm.interlace_type = PNG_INTERLACE_ADAM7;
11917# else /* !CAN_WRITE_INTERLACE */
11918 fprintf(stderr, "pngvalid: no write interlace support\n");
11919 return SKIP;
11920# endif /* !CAN_WRITE_INTERLACE */
11921 }
11922
11923 else if (strcmp(*argv, "--use-input-precision") == 0)
11924 pm.use_input_precision = 1U;
11925
11926 else if (strcmp(*argv, "--use-calculation-precision") == 0)
11927 pm.use_input_precision = 0;
11928
11929 else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
11930 pm.calculations_use_input_precision = 1U;
11931
11932 else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
11933 pm.assume_16_bit_calculations = 1U;
11934
11935 else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
11936 pm.calculations_use_input_precision =
11937 pm.assume_16_bit_calculations = 0;
11938
11939 else if (strcmp(*argv, "--exhaustive") == 0)
11940 pm.test_exhaustive = 1;
11941
11942 else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
11943 --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
11944
11945 else if (argc > 1 && strcmp(*argv, "--touch") == 0)
11946 --argc, touch = *++argv, catmore = 1;
11947
11948 else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
11949 {
11950 --argc;
11951
11952 if (strcmp(5+*argv, "abs8") == 0)
11953 pm.maxabs8 = atof(*++argv);
11954
11955 else if (strcmp(5+*argv, "abs16") == 0)
11956 pm.maxabs16 = atof(*++argv);
11957
11958 else if (strcmp(5+*argv, "calc8") == 0)
11959 pm.maxcalc8 = atof(*++argv);
11960
11961 else if (strcmp(5+*argv, "calc16") == 0)
11962 pm.maxcalc16 = atof(*++argv);
11963
11964 else if (strcmp(5+*argv, "out8") == 0)
11965 pm.maxout8 = atof(*++argv);
11966
11967 else if (strcmp(5+*argv, "out16") == 0)
11968 pm.maxout16 = atof(*++argv);
11969
11970 else if (strcmp(5+*argv, "pc8") == 0)
11971 pm.maxpc8 = atof(*++argv);
11972
11973 else if (strcmp(5+*argv, "pc16") == 0)
11974 pm.maxpc16 = atof(*++argv);
11975
11976 else
11977 {
11978 fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
11979 exit(99);
11980 }
11981
11982 catmore = 1;
11983 }
11984
11985 else if (strcmp(*argv, "--log8") == 0)
11986 --argc, pm.log8 = atof(*++argv), catmore = 1;
11987
11988 else if (strcmp(*argv, "--log16") == 0)
11989 --argc, pm.log16 = atof(*++argv), catmore = 1;
11990
11991#ifdef PNG_SET_OPTION_SUPPORTED
11992 else if (strncmp(*argv, "--option=", 9) == 0)
11993 {
11994 /* Syntax of the argument is <option>:{on|off} */
11995 const char *arg = 9+*argv;
11996 unsigned char option=0, setting=0;
11997
11998#ifdef PNG_ARM_NEON
11999 if (strncmp(arg, "arm-neon:", 9) == 0)
12000 option = PNG_ARM_NEON, arg += 9;
12001
12002 else
12003#endif
12004#ifdef PNG_EXTENSIONS
12005 if (strncmp(arg, "extensions:", 11) == 0)
12006 option = PNG_EXTENSIONS, arg += 11;
12007
12008 else
12009#endif
12010#ifdef PNG_MAXIMUM_INFLATE_WINDOW
12011 if (strncmp(arg, "max-inflate-window:", 19) == 0)
12012 option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19;
12013
12014 else
12015#endif
12016 {
12017 fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg);
12018 exit(99);
12019 }
12020
12021 if (strcmp(arg, "off") == 0)
12022 setting = PNG_OPTION_OFF;
12023
12024 else if (strcmp(arg, "on") == 0)
12025 setting = PNG_OPTION_ON;
12026
12027 else
12028 {
12029 fprintf(stderr,
12030 "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n",
12031 *argv, arg);
12032 exit(99);
12033 }
12034
12035 pm.this.options[pm.this.noptions].option = option;
12036 pm.this.options[pm.this.noptions++].setting = setting;
12037 }
12038#endif /* PNG_SET_OPTION_SUPPORTED */
12039
12040 else
12041 {
12042 fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
12043 exit(99);
12044 }
12045
12046 if (catmore) /* consumed an extra *argv */
12047 {
12048 cp = safecat(command, sizeof command, cp, " ");
12049 cp = safecat(command, sizeof command, cp, *argv);
12050 }
12051 }
12052
12053 /* If pngvalid is run with no arguments default to a reasonable set of the
12054 * tests.
12055 */
12056 if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
12057 pm.ngamma_tests == 0)
12058 {
12059 /* Make this do all the tests done in the test shell scripts with the same
12060 * parameters, where possible. The limitation is that all the progressive
12061 * read and interlace stuff has to be done in separate runs, so only the
12062 * basic 'standard' and 'size' tests are done.
12063 */
12064 pm.test_standard = 1;
12065 pm.test_size = 1;
12066 pm.test_transform = 1;
12067 pm.ngamma_tests = 2U;
12068 }
12069
12070 if (pm.ngamma_tests > 0 &&
12071 pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
12072 pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
12073 pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
12074 {
12075 pm.test_gamma_threshold = 1;
12076 pm.test_gamma_transform = 1;
12077 pm.test_gamma_sbit = 1;
12078 pm.test_gamma_scale16 = 1;
12079 pm.test_gamma_background = 1;
12080 pm.test_gamma_alpha_mode = 1;
12081 }
12082
12083 else if (pm.ngamma_tests == 0)
12084 {
12085 /* Nothing to test so turn everything off: */
12086 pm.test_gamma_threshold = 0;
12087 pm.test_gamma_transform = 0;
12088 pm.test_gamma_sbit = 0;
12089 pm.test_gamma_scale16 = 0;
12090 pm.test_gamma_background = 0;
12091 pm.test_gamma_alpha_mode = 0;
12092 }
12093
12094 Try
12095 {
12096 /* Make useful base images */
12097 make_transform_images(&pm);
12098
12099 /* Perform the standard and gamma tests. */
12100 if (pm.test_standard)
12101 {
12102 perform_interlace_macro_validation();
12103 perform_formatting_test(&pm.this);
12104# ifdef PNG_READ_SUPPORTED
12105 perform_standard_test(&pm);
12106# endif
12107 perform_error_test(&pm);
12108 }
12109
12110 /* Various oddly sized images: */
12111 if (pm.test_size)
12112 {
12113 make_size_images(&pm.this);
12114# ifdef PNG_READ_SUPPORTED
12115 perform_size_test(&pm);
12116# endif
12117 }
12118
12119#ifdef PNG_READ_TRANSFORMS_SUPPORTED
12120 /* Combinatorial transforms: */
12121 if (pm.test_transform)
12122 perform_transform_test(&pm);
12123#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
12124
12125#ifdef PNG_READ_GAMMA_SUPPORTED
12126 if (pm.ngamma_tests > 0)
12127 perform_gamma_test(&pm, summary);
12128#endif
12129 }
12130
12131 Catch_anonymous
12132 {
12133 fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
12134 if (!pm.this.verbose)
12135 {
12136 if (pm.this.error[0] != 0)
12137 fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
12138
12139 fprintf(stderr, "pngvalid: run with -v to see what happened\n");
12140 }
12141 exit(1);
12142 }
12143
12144 if (summary)
12145 {
12146 printf("%s: %s (%s point arithmetic)\n",
12147 (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12148 pm.this.nwarnings)) ? "FAIL" : "PASS",
12149 command,
12150#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
12151 "floating"
12152#else
12153 "fixed"
12154#endif
12155 );
12156 }
12157
12158 if (memstats)
12159 {
12160 printf("Allocated memory statistics (in bytes):\n"
12161 "\tread %lu maximum single, %lu peak, %lu total\n"
12162 "\twrite %lu maximum single, %lu peak, %lu total\n",
12163 (unsigned long)pm.this.read_memory_pool.max_max,
12164 (unsigned long)pm.this.read_memory_pool.max_limit,
12165 (unsigned long)pm.this.read_memory_pool.max_total,
12166 (unsigned long)pm.this.write_memory_pool.max_max,
12167 (unsigned long)pm.this.write_memory_pool.max_limit,
12168 (unsigned long)pm.this.write_memory_pool.max_total);
12169 }
12170
12171 /* Do this here to provoke memory corruption errors in memory not directly
12172 * allocated by libpng - not a complete test, but better than nothing.
12173 */
12174 store_delete(&pm.this);
12175
12176 /* Error exit if there are any errors, and maybe if there are any
12177 * warnings.
12178 */
12179 if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12180 pm.this.nwarnings))
12181 {
12182 if (!pm.this.verbose)
12183 fprintf(stderr, "pngvalid: %s\n", pm.this.error);
12184
12185 fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
12186 pm.this.nwarnings);
12187
12188 exit(1);
12189 }
12190
12191 /* Success case. */
12192 if (touch != NULL)
12193 {
12194 FILE *fsuccess = fopen(touch, "wt");
12195
12196 if (fsuccess != NULL)
12197 {
12198 int error = 0;
12199 fprintf(fsuccess, "PNG validation succeeded\n");
12200 fflush(fsuccess);
12201 error = ferror(fsuccess);
12202
12203 if (fclose(fsuccess) || error)
12204 {
12205 fprintf(stderr, "%s: write failed\n", touch);
12206 exit(1);
12207 }
12208 }
12209
12210 else
12211 {
12212 fprintf(stderr, "%s: open failed\n", touch);
12213 exit(1);
12214 }
12215 }
12216
12217 /* This is required because some very minimal configurations do not use it:
12218 */
12219 UNUSED(fail)
12220 return 0;
12221}
12222#else /* write or low level APIs not supported */
12223int main(void)
12224{
12225 fprintf(stderr,
12226 "pngvalid: no low level write support in libpng, all tests skipped\n");
12227 /* So the test is skipped: */
12228 return SKIP;
12229}
12230#endif