/*- iccfrompng

 *

 * COPYRIGHT: Written by John Cunningham Bowler, 2011.

 * To the extent possible under law, the author has waived all copyright and

 * related or neighboring rights to this work.  This work is published from:

 * United States.

 *

 * Extract any icc profiles found in the given PNG files.  This is a simple

 * example of a program that extracts information from the header of a PNG file

 * without processing the image.  Notice that some header information may occur

 * after the image data. Textual data and comments are an example; the approach

 * in this file won't work reliably for such data because it only looks for the

 * information in the section of the file that preceeds the image data.

 *

 * Compile and link against libpng and zlib, plus anything else required on the

 * system you use.

 *

 * To use supply a list of PNG files containing iCCP chunks, the chunks will be

 * extracted to a similarly named file with the extension replaced by 'icc',

 * which will be overwritten without warning.

 */

#include <stdlib.h></stdlib.h>

#include <setjmp.h></setjmp.h>

#include <string.h></string.h>

#include <stdio.h></stdio.h>

#include <png.h></png.h>

#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \

    defined (PNG_iCCP_SUPPORTED)

static int verbose = 1;

static png_byte no_profile[] = "no profile";

static png_bytep

extract(FILE *fp, png_uint_32 *proflen)

{

   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);

   png_infop info_ptr = NULL;

   png_bytep result = NULL;

   /* Initialize for error or no profile: */

   *proflen = 0;

   if (png_ptr == NULL)

   {

      fprintf(stderr, "iccfrompng: version library mismatch?\n");

      return 0;

   }

   if (setjmp(png_jmpbuf(png_ptr)))

   {

      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);

      return 0;

   }

   png_init_io(png_ptr, fp);

   info_ptr = png_create_info_struct(png_ptr);

   if (info_ptr == NULL)

      png_error(png_ptr, "OOM allocating info structure");

   png_read_info(png_ptr, info_ptr);

   {

      png_charp name;

      int compression_type;

      png_bytep profile;

      if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,

         proflen) & PNG_INFO_iCCP)

      {

         result = malloc(*proflen);

         if (result != NULL)

            memcpy(result, profile, *proflen);

         else

            png_error(png_ptr, "OOM allocating profile buffer");

      }

      else

	result = no_profile;

   }

   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);

   return result;

}

static int

extract_one_file(const char *filename)

{

   int result = 0;

   FILE *fp = fopen(filename, "rb");

   if (fp != NULL)

   {

      png_uint_32 proflen = 0;

      png_bytep profile = extract(fp, &proflen);

      if (profile != NULL && profile != no_profile)

      {

         size_t len;

         char *output;

         {

            const char *ep = strrchr(filename, '.');

            if (ep != NULL)

               len = ep-filename;

            else

               len = strlen(filename);

         }

         output = malloc(len + 5);

         if (output != NULL)

         {

            FILE *of;

            memcpy(output, filename, len);

            strcpy(output+len, ".icc");

            of = fopen(output, "wb");

            if (of != NULL)

            {

               if (fwrite(profile, proflen, 1, of) == 1 &&

                  fflush(of) == 0 &&

                  fclose(of) == 0)

               {

                  if (verbose)

                     printf("%s -> %s\n", filename, output);

                  /* Success return */

                  result = 1;

               }

               else

               {

                  fprintf(stderr, "%s: error writing profile\n", output);

                  if (remove(output))

                     fprintf(stderr, "%s: could not remove file\n", output);

               }

            }

            else

               fprintf(stderr, "%s: failed to open output file\n", output);

            free(output);

         }

         else

            fprintf(stderr, "%s: OOM allocating string!\n", filename);

         free(profile);

      }

      else if (verbose && profile == no_profile)

	printf("%s has no profile\n", filename);

   }

   else

      fprintf(stderr, "%s: could not open file\n", filename);

   return result;

}

int

main(int argc, char **argv)

{

   int i;

   int extracted = 0;

   for (i=1; i

   {

      if (strcmp(argv[i], "-q") == 0)

         verbose = 0;

      else if (extract_one_file(argv[i]))

         extracted = 1;

   }

   /* Exit code is true if any extract succeeds */

   return extracted == 0;

}

#endif /* READ && STDIO && iCCP */