workbench/libs/png/contrib/examples/iccfrompng.c

   1 /*- iccfrompng
   2  *
   3  * COPYRIGHT: Written by John Cunningham Bowler, 2011.
   4  * To the extent possible under law, the author has waived all copyright and
   5  * related or neighboring rights to this work.  This work is published from:
   6  * United States.
   7  *
   8  * Extract any icc profiles found in the given PNG files.  This is a simple
   9  * example of a program that extracts information from the header of a PNG file
  10  * without processing the image.  Notice that some header information may occur
  11  * after the image data. Textual data and comments are an example; the approach
  12  * in this file won't work reliably for such data because it only looks for the
  13  * information in the section of the file that precedes the image data.
  14  *
  15  * Compile and link against libpng and zlib, plus anything else required on the
  16  * system you use.
  17  *
  18  * To use supply a list of PNG files containing iCCP chunks, the chunks will be
  19  * extracted to a similarly named file with the extension replaced by 'icc',
  20  * which will be overwritten without warning.
  21  */
  22 #include <stdlib.h>
  23 #include <setjmp.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26
  27 #include <png.h>
  28
  29 #if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
  30     defined (PNG_iCCP_SUPPORTED)
  31
  32
  33 static int verbose = 1;
  34 static png_byte no_profile[] = "no profile";
  35
  36 static png_bytep
  37 extract(FILE *fp, png_uint_32 *proflen)
  38 {
  39    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
  40    png_infop info_ptr = NULL;
  41    png_bytep result = NULL;
  42
  43    /* Initialize for error or no profile: */
  44    *proflen = 0;
  45
  46    if (png_ptr == NULL)
  47    {
  48       fprintf(stderr, "iccfrompng: version library mismatch?\n");
  49       return 0;
  50    }
  51
  52    if (setjmp(png_jmpbuf(png_ptr)))
  53    {
  54       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
  55       return 0;
  56    }
  57
  58    png_init_io(png_ptr, fp);
  59
  60    info_ptr = png_create_info_struct(png_ptr);
  61    if (info_ptr == NULL)
  62       png_error(png_ptr, "OOM allocating info structure");
  63
  64    png_read_info(png_ptr, info_ptr);
  65
  66    {
  67       png_charp name;
  68       int compression_type;
  69       png_bytep profile;
  70
  71       if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
  72          proflen) & PNG_INFO_iCCP)
  73       {
  74          result = malloc(*proflen);
  75          if (result != NULL)
  76             memcpy(result, profile, *proflen);
  77
  78          else
  79             png_error(png_ptr, "OOM allocating profile buffer");
  80       }
  81
  82       else
  83         result = no_profile;
  84    }
  85
  86    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
  87    return result;
  88 }
  89
  90 static int
  91 extract_one_file(const char *filename)
  92 {
  93    int result = 0;
  94    FILE *fp = fopen(filename, "rb");
  95
  96    if (fp != NULL)
  97    {
  98       png_uint_32 proflen = 0;
  99       png_bytep profile = extract(fp, &proflen);
 100
 101       if (profile != NULL && profile != no_profile)
 102       {
 103          size_t len;
 104          char *output;
 105
 106          {
 107             const char *ep = strrchr(filename, '.');
 108
 109             if (ep != NULL)
 110                len = ep-filename;
 111
 112             else
 113                len = strlen(filename);
 114          }
 115
 116          output = malloc(len + 5);
 117          if (output != NULL)
 118          {
 119             FILE *of;
 120
 121             memcpy(output, filename, len);
 122             strcpy(output+len, ".icc");
 123
 124             of = fopen(output, "wb");
 125             if (of != NULL)
 126             {
 127                if (fwrite(profile, proflen, 1, of) == 1 &&
 128                   fflush(of) == 0 &&
 129                   fclose(of) == 0)
 130                {
 131                   if (verbose)
 132                      printf("%s -> %s\n", filename, output);
 133                   /* Success return */
 134                   result = 1;
 135                }
 136
 137                else
 138                {
 139                   fprintf(stderr, "%s: error writing profile\n", output);
 140                   if (remove(output))
 141                      fprintf(stderr, "%s: could not remove file\n", output);
 142                }
 143             }
 144
 145             else
 146                fprintf(stderr, "%s: failed to open output file\n", output);
 147
 148             free(output);
 149          }
 150
 151          else
 152             fprintf(stderr, "%s: OOM allocating string!\n", filename);
 153
 154          free(profile);
 155       }
 156
 157       else if (verbose && profile == no_profile)
 158         printf("%s has no profile\n", filename);
 159    }
 160
 161    else
 162       fprintf(stderr, "%s: could not open file\n", filename);
 163
 164    return result;
 165 }
 166
 167 int
 168 main(int argc, char **argv)
 169 {
 170    int i;
 171    int extracted = 0;
 172
 173    for (i=1; i<argc; ++i)
 174    {
 175       if (strcmp(argv[i], "-q") == 0)
 176          verbose = 0;
 177
 178       else if (extract_one_file(argv[i]))
 179          extracted = 1;
 180    }
 181
 182    /* Exit code is true if any extract succeeds */
 183    return extracted == 0;
 184 }
 185 #endif /* READ && STDIO && iCCP */