src/third-party/zlib/contrib/ada/zlib.ads (view raw)
1------------------------------------------------------------------------------
2-- ZLib for Ada thick binding. --
3-- --
4-- Copyright (C) 2002-2004 Dmitriy Anisimkov --
5-- --
6-- This library is free software; you can redistribute it and/or modify --
7-- it under the terms of the GNU General Public License as published by --
8-- the Free Software Foundation; either version 2 of the License, or (at --
9-- your option) any later version. --
10-- --
11-- This library is distributed in the hope that it will be useful, but --
12-- WITHOUT ANY WARRANTY; without even the implied warranty of --
13-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
14-- General Public License for more details. --
15-- --
16-- You should have received a copy of the GNU General Public License --
17-- along with this library; if not, write to the Free Software Foundation, --
18-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
19-- --
20-- As a special exception, if other files instantiate generics from this --
21-- unit, or you link this unit with other files to produce an executable, --
22-- this unit does not by itself cause the resulting executable to be --
23-- covered by the GNU General Public License. This exception does not --
24-- however invalidate any other reasons why the executable file might be --
25-- covered by the GNU Public License. --
26------------------------------------------------------------------------------
27
28-- $Id: zlib.ads,v 1.26 2004/09/06 06:53:19 vagul Exp $
29
30with Ada.Streams;
31
32with Interfaces;
33
34package ZLib is
35
36 ZLib_Error : exception;
37 Status_Error : exception;
38
39 type Compression_Level is new Integer range -1 .. 9;
40
41 type Flush_Mode is private;
42
43 type Compression_Method is private;
44
45 type Window_Bits_Type is new Integer range 8 .. 15;
46
47 type Memory_Level_Type is new Integer range 1 .. 9;
48
49 type Unsigned_32 is new Interfaces.Unsigned_32;
50
51 type Strategy_Type is private;
52
53 type Header_Type is (None, Auto, Default, GZip);
54 -- Header type usage have a some limitation for inflate.
55 -- See comment for Inflate_Init.
56
57 subtype Count is Ada.Streams.Stream_Element_Count;
58
59 Default_Memory_Level : constant Memory_Level_Type := 8;
60 Default_Window_Bits : constant Window_Bits_Type := 15;
61
62 ----------------------------------
63 -- Compression method constants --
64 ----------------------------------
65
66 Deflated : constant Compression_Method;
67 -- Only one method allowed in this ZLib version
68
69 ---------------------------------
70 -- Compression level constants --
71 ---------------------------------
72
73 No_Compression : constant Compression_Level := 0;
74 Best_Speed : constant Compression_Level := 1;
75 Best_Compression : constant Compression_Level := 9;
76 Default_Compression : constant Compression_Level := -1;
77
78 --------------------------
79 -- Flush mode constants --
80 --------------------------
81
82 No_Flush : constant Flush_Mode;
83 -- Regular way for compression, no flush
84
85 Partial_Flush : constant Flush_Mode;
86 -- Will be removed, use Z_SYNC_FLUSH instead
87
88 Sync_Flush : constant Flush_Mode;
89 -- All pending output is flushed to the output buffer and the output
90 -- is aligned on a byte boundary, so that the decompressor can get all
91 -- input data available so far. (In particular avail_in is zero after the
92 -- call if enough output space has been provided before the call.)
93 -- Flushing may degrade compression for some compression algorithms and so
94 -- it should be used only when necessary.
95
96 Block_Flush : constant Flush_Mode;
97 -- Z_BLOCK requests that inflate() stop
98 -- if and when it get to the next deflate block boundary. When decoding the
99 -- zlib or gzip format, this will cause inflate() to return immediately
100 -- after the header and before the first block. When doing a raw inflate,
101 -- inflate() will go ahead and process the first block, and will return
102 -- when it gets to the end of that block, or when it runs out of data.
103
104 Full_Flush : constant Flush_Mode;
105 -- All output is flushed as with SYNC_FLUSH, and the compression state
106 -- is reset so that decompression can restart from this point if previous
107 -- compressed data has been damaged or if random access is desired. Using
108 -- Full_Flush too often can seriously degrade the compression.
109
110 Finish : constant Flush_Mode;
111 -- Just for tell the compressor that input data is complete.
112
113 ------------------------------------
114 -- Compression strategy constants --
115 ------------------------------------
116
117 -- RLE stategy could be used only in version 1.2.0 and later.
118
119 Filtered : constant Strategy_Type;
120 Huffman_Only : constant Strategy_Type;
121 RLE : constant Strategy_Type;
122 Default_Strategy : constant Strategy_Type;
123
124 Default_Buffer_Size : constant := 4096;
125
126 type Filter_Type is tagged limited private;
127 -- The filter is for compression and for decompression.
128 -- The usage of the type is depend of its initialization.
129
130 function Version return String;
131 pragma Inline (Version);
132 -- Return string representation of the ZLib version.
133
134 procedure Deflate_Init
135 (Filter : in out Filter_Type;
136 Level : in Compression_Level := Default_Compression;
137 Strategy : in Strategy_Type := Default_Strategy;
138 Method : in Compression_Method := Deflated;
139 Window_Bits : in Window_Bits_Type := Default_Window_Bits;
140 Memory_Level : in Memory_Level_Type := Default_Memory_Level;
141 Header : in Header_Type := Default);
142 -- Compressor initialization.
143 -- When Header parameter is Auto or Default, then default zlib header
144 -- would be provided for compressed data.
145 -- When Header is GZip, then gzip header would be set instead of
146 -- default header.
147 -- When Header is None, no header would be set for compressed data.
148
149 procedure Inflate_Init
150 (Filter : in out Filter_Type;
151 Window_Bits : in Window_Bits_Type := Default_Window_Bits;
152 Header : in Header_Type := Default);
153 -- Decompressor initialization.
154 -- Default header type mean that ZLib default header is expecting in the
155 -- input compressed stream.
156 -- Header type None mean that no header is expecting in the input stream.
157 -- GZip header type mean that GZip header is expecting in the
158 -- input compressed stream.
159 -- Auto header type mean that header type (GZip or Native) would be
160 -- detected automatically in the input stream.
161 -- Note that header types parameter values None, GZip and Auto are
162 -- supported for inflate routine only in ZLib versions 1.2.0.2 and later.
163 -- Deflate_Init is supporting all header types.
164
165 function Is_Open (Filter : in Filter_Type) return Boolean;
166 pragma Inline (Is_Open);
167 -- Is the filter opened for compression or decompression.
168
169 procedure Close
170 (Filter : in out Filter_Type;
171 Ignore_Error : in Boolean := False);
172 -- Closing the compression or decompressor.
173 -- If stream is closing before the complete and Ignore_Error is False,
174 -- The exception would be raised.
175
176 generic
177 with procedure Data_In
178 (Item : out Ada.Streams.Stream_Element_Array;
179 Last : out Ada.Streams.Stream_Element_Offset);
180 with procedure Data_Out
181 (Item : in Ada.Streams.Stream_Element_Array);
182 procedure Generic_Translate
183 (Filter : in out Filter_Type;
184 In_Buffer_Size : in Integer := Default_Buffer_Size;
185 Out_Buffer_Size : in Integer := Default_Buffer_Size);
186 -- Compress/decompress data fetch from Data_In routine and pass the result
187 -- to the Data_Out routine. User should provide Data_In and Data_Out
188 -- for compression/decompression data flow.
189 -- Compression or decompression depend on Filter initialization.
190
191 function Total_In (Filter : in Filter_Type) return Count;
192 pragma Inline (Total_In);
193 -- Returns total number of input bytes read so far
194
195 function Total_Out (Filter : in Filter_Type) return Count;
196 pragma Inline (Total_Out);
197 -- Returns total number of bytes output so far
198
199 function CRC32
200 (CRC : in Unsigned_32;
201 Data : in Ada.Streams.Stream_Element_Array)
202 return Unsigned_32;
203 pragma Inline (CRC32);
204 -- Compute CRC32, it could be necessary for make gzip format
205
206 procedure CRC32
207 (CRC : in out Unsigned_32;
208 Data : in Ada.Streams.Stream_Element_Array);
209 pragma Inline (CRC32);
210 -- Compute CRC32, it could be necessary for make gzip format
211
212 -------------------------------------------------
213 -- Below is more complex low level routines. --
214 -------------------------------------------------
215
216 procedure Translate
217 (Filter : in out Filter_Type;
218 In_Data : in Ada.Streams.Stream_Element_Array;
219 In_Last : out Ada.Streams.Stream_Element_Offset;
220 Out_Data : out Ada.Streams.Stream_Element_Array;
221 Out_Last : out Ada.Streams.Stream_Element_Offset;
222 Flush : in Flush_Mode);
223 -- Compress/decompress the In_Data buffer and place the result into
224 -- Out_Data. In_Last is the index of last element from In_Data accepted by
225 -- the Filter. Out_Last is the last element of the received data from
226 -- Filter. To tell the filter that incoming data are complete put the
227 -- Flush parameter to Finish.
228
229 function Stream_End (Filter : in Filter_Type) return Boolean;
230 pragma Inline (Stream_End);
231 -- Return the true when the stream is complete.
232
233 procedure Flush
234 (Filter : in out Filter_Type;
235 Out_Data : out Ada.Streams.Stream_Element_Array;
236 Out_Last : out Ada.Streams.Stream_Element_Offset;
237 Flush : in Flush_Mode);
238 pragma Inline (Flush);
239 -- Flushing the data from the compressor.
240
241 generic
242 with procedure Write
243 (Item : in Ada.Streams.Stream_Element_Array);
244 -- User should provide this routine for accept
245 -- compressed/decompressed data.
246
247 Buffer_Size : in Ada.Streams.Stream_Element_Offset
248 := Default_Buffer_Size;
249 -- Buffer size for Write user routine.
250
251 procedure Write
252 (Filter : in out Filter_Type;
253 Item : in Ada.Streams.Stream_Element_Array;
254 Flush : in Flush_Mode := No_Flush);
255 -- Compress/Decompress data from Item to the generic parameter procedure
256 -- Write. Output buffer size could be set in Buffer_Size generic parameter.
257
258 generic
259 with procedure Read
260 (Item : out Ada.Streams.Stream_Element_Array;
261 Last : out Ada.Streams.Stream_Element_Offset);
262 -- User should provide data for compression/decompression
263 -- thru this routine.
264
265 Buffer : in out Ada.Streams.Stream_Element_Array;
266 -- Buffer for keep remaining data from the previous
267 -- back read.
268
269 Rest_First, Rest_Last : in out Ada.Streams.Stream_Element_Offset;
270 -- Rest_First have to be initialized to Buffer'Last + 1
271 -- Rest_Last have to be initialized to Buffer'Last
272 -- before usage.
273
274 Allow_Read_Some : in Boolean := False;
275 -- Is it allowed to return Last < Item'Last before end of data.
276
277 procedure Read
278 (Filter : in out Filter_Type;
279 Item : out Ada.Streams.Stream_Element_Array;
280 Last : out Ada.Streams.Stream_Element_Offset;
281 Flush : in Flush_Mode := No_Flush);
282 -- Compress/Decompress data from generic parameter procedure Read to the
283 -- Item. User should provide Buffer and initialized Rest_First, Rest_Last
284 -- indicators. If Allow_Read_Some is True, Read routines could return
285 -- Last < Item'Last only at end of stream.
286
287private
288
289 use Ada.Streams;
290
291 pragma Assert (Ada.Streams.Stream_Element'Size = 8);
292 pragma Assert (Ada.Streams.Stream_Element'Modulus = 2**8);
293
294 type Flush_Mode is new Integer range 0 .. 5;
295
296 type Compression_Method is new Integer range 8 .. 8;
297
298 type Strategy_Type is new Integer range 0 .. 3;
299
300 No_Flush : constant Flush_Mode := 0;
301 Partial_Flush : constant Flush_Mode := 1;
302 Sync_Flush : constant Flush_Mode := 2;
303 Full_Flush : constant Flush_Mode := 3;
304 Finish : constant Flush_Mode := 4;
305 Block_Flush : constant Flush_Mode := 5;
306
307 Filtered : constant Strategy_Type := 1;
308 Huffman_Only : constant Strategy_Type := 2;
309 RLE : constant Strategy_Type := 3;
310 Default_Strategy : constant Strategy_Type := 0;
311
312 Deflated : constant Compression_Method := 8;
313
314 type Z_Stream;
315
316 type Z_Stream_Access is access all Z_Stream;
317
318 type Filter_Type is tagged limited record
319 Strm : Z_Stream_Access;
320 Compression : Boolean;
321 Stream_End : Boolean;
322 Header : Header_Type;
323 CRC : Unsigned_32;
324 Offset : Stream_Element_Offset;
325 -- Offset for gzip header/footer output.
326 end record;
327
328end ZLib;