1#!/bin/awk -f
  2# scripts/dfn.awk - process a .dfn file
  3#
  4# last changed in libpng version 1.5.19 - August 21, 2014
  5#
  6# Copyright (c) 2013-2014 Glenn Randers-Pehrson
  7#
  8# This code is released under the libpng license.
  9# For conditions of distribution and use, see the disclaimer
 10# and license in png.h
 11
 12# The output of this script is written to the file given by
 13# the variable 'out', which should be set on the command line.
 14# Error messages are printed to stdout and if any are printed
 15# the script will exit with error code 1.
 16
 17BEGIN{
 18   out="/dev/null"       # as a flag
 19   out_count=0           # count of output lines
 20   err=0                 # set if an error occurred
 21   sort=0                # sort the output
 22   array[""]=""
 23}
 24
 25# The output file must be specified before any input:
 26NR==1 && out == "/dev/null" {
 27   print "out=output.file must be given on the command line"
 28   # but continue without setting the error code; this allows the
 29   # script to be checked easily
 30}
 31
 32# Output can be sorted; two lines are recognized
 33$1 == "PNG_DFN_START_SORT"{
 34   sort=0+$2
 35   next
 36}
 37
 38$1 ~ /^PNG_DFN_END_SORT/{
 39   # Do a very simple, slow, sort; notice that blank lines won't be
 40   # output by this
 41   for (entry in array) {
 42      while (array[entry] != "") {
 43         key = entry
 44         value = array[key]
 45         array[key] = ""
 46
 47         for (alt in array) {
 48            if (array[alt] != "" && alt < key) {
 49               array[key] = value
 50               value = array[alt]
 51               key = alt
 52               array[alt] = ""
 53            }
 54         }
 55
 56         print value >out
 57      }
 58   }
 59   sort=0
 60   next
 61}
 62
 63/^[^"]*PNG_DFN *".*"[^"]*$/{
 64   # A definition line, apparently correctly formatted; extract the
 65   # definition then replace any doubled "" that remain with a single
 66   # double quote.  Notice that the original doubled double quotes
 67   # may have been split by tokenization
 68   #
 69   # Sometimes GCC splits the PNG_DFN lines; we know this has happened
 70   # if the quotes aren't closed and must read another line.  In this
 71   # case it is essential to reject lines that start with '#' because those
 72   # are introduced #line directives.
 73   orig=$0
 74   line=$0
 75   lineno=FNR
 76   if (lineno == "") lineno=NR
 77
 78   if (sub(/^[^"]*PNG_DFN *"/,"",line) != 1) {
 79	print "line", lineno ": processing failed:"
 80	print orig
 81	err=1
 82       next
 83   } else {
 84	++out_count
 85   }
 86
 87   # Now examine quotes within the value:
 88   #
 89   #   @" - delete this and any following spaces
 90   #   "@ - delete this and any preceding spaces
 91   #   @' - replace this by a double quote
 92   #
 93   # This allows macro substitution by the C compiler thus:
 94   #
 95   #   #define first_name John
 96   #   #define last_name Smith
 97   #
 98   #	PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
 99   #
100   # Might get C preprocessed to:
101   #
102   #   PNG_DFN "#define foo @'@" John "@ @" Smith "@@'"
103   #
104   # Which this script reduces to:
105   #
106   #	#define name "John Smith"
107   #
108   while (1) {
109      # While there is an @" remove it and the next "@
110      if (line ~ /@"/) {
111         if (line ~ /@".*"@/) {
112            # Do this special case first to avoid swallowing extra spaces
113            # before or after the @ stuff:
114            if (!sub(/@" *"@/, "", line)) {
115               # Ok, do it in pieces - there has to be a non-space between the
116               # two.  NOTE: really weird things happen if a leading @" is
117               # lost - the code will error out below (I believe).
118               if (!sub(/@" */, "", line) || !sub(/ *"@/, "", line)) {
119                  print "line", lineno, ": internal error:", orig
120                  exit 1
121               }
122            }
123         }
124
125         # There is no matching "@.  Assume a split line
126         else while (1) {
127            if (getline nextline) {
128               # If the line starts with '#' it is a preprocesor line directive
129               # from cc -E; skip it:
130               if (nextline !~ /^#/) {
131                  line = line " " nextline
132                  break
133               }
134            } else {
135               # This is end-of-input - probably a missing "@ on the first line:
136               print "line", lineno ": unbalanced @\" ... \"@ pair"
137               err=1
138               next
139            }
140         }
141
142         # Keep going until all the @" have gone
143         continue
144      }
145
146      # Attempt to remove a trailing " (not preceded by '@') - if this can
147      # be done, stop now; if not assume a split line again
148      if (sub(/"[^"]*$/, "", line))
149         break
150
151      # Read another line
152      while (1) {
153         if (getline nextline) {
154            if (nextline !~ /^#/) {
155               line = line " " nextline
156               # Go back to stripping @" "@ pairs
157               break
158            }
159         } else {
160            print "line", lineno ": unterminated PNG_DFN string"
161            err=1
162            next
163         }
164      }
165   }
166
167   # Put any needed double quotes in (at the end, because these would otherwise
168   # interfere with the processing above.)
169   gsub(/@'/,"\"", line)
170
171   # Remove any trailing spaces (not really required, but for
172   # editorial consistency
173   sub(/ *$/, "", line)
174
175   # Remove trailing CR
176   sub(/
177$/, "", line)
178
179   if (sort) {
180      if (split(line, parts) < sort) {
181         print "line", lineno ": missing sort field:", line
182         err=1
183      } else
184         array[parts[sort]] = line
185   }
186
187   else
188      print line >out
189   next
190}
191
192/PNG_DFN/{
193   print "line", NR, "incorrectly formatted PNG_DFN line:"
194   print $0
195   err = 1
196}
197
198END{
199   if (out_count > 0 || err > 0)
200	exit err
201
202   print "no definition lines found"
203   exit 1
204}