add-profile.c

/*
 * add-profile.c ... paste an ICC profile into a JPG file, without
 * decompress/recompress.
 *
 * Adapted from wrjpgcom.c
 *
 * compile with:
 *
 * 	gcc -g -Wall add-profile.c `pkg-config glib-2.0 --cflags --libs`
 */

#include <glib.h>
#include <stdio.h>

/*
 * These macros are used to read the input file and write the output file.
 * To reuse this code in another application, you might need to change these.
 */

static FILE * infile;		/* input JPEG file */

/* Return next input byte, or EOF if no more */
#define NEXTBYTE()  getc(infile)

static FILE * outfile;		/* output JPEG file */

/* Emit an output byte */
#define PUTBYTE(x)  putc((x), outfile)


#define ERREXIT(msg)  (fprintf(stderr, "%s\n", msg), exit(1))


/* Read one byte, testing for EOF */
static int
read_1_byte (void)
{
  int c;

  c = NEXTBYTE();
  if (c == EOF)
    ERREXIT("Premature EOF in JPEG file");
  return c;
}

/* Read 2 bytes, convert to unsigned int */
/* All 2-byte quantities in JPEG markers are MSB first */
static unsigned int
read_2_bytes (void)
{
  int c1, c2;

  c1 = NEXTBYTE();
  if (c1 == EOF)
    ERREXIT("Premature EOF in JPEG file");
  c2 = NEXTBYTE();
  if (c2 == EOF)
    ERREXIT("Premature EOF in JPEG file");
  return (((unsigned int) c1) << 8) + ((unsigned int) c2);
}


/* Routines to write data to output file */

static void
write_1_byte (int c)
{
  PUTBYTE(c);
}

static void
write_2_bytes (unsigned int val)
{
  PUTBYTE((val >> 8) & 0xFF);
  PUTBYTE(val & 0xFF);
}

static void
write_marker (int marker)
{
  PUTBYTE(0xFF);
  PUTBYTE(marker);
}

static void
copy_rest_of_file (void)
{
  int c;
  printf("copy_rest_of_file:\n");

  while ((c = NEXTBYTE()) != EOF)
    PUTBYTE(c);
}


/*
 * JPEG markers consist of one or more 0xFF bytes, followed by a marker
 * code byte (which is not an FF).  Here are the marker codes of interest
 * in this program.  (See jdmarker.c for a more complete list.)
 */

#define M_SOF0  0xC0		/* Start Of Frame N */
#define M_SOF1  0xC1		/* N indicates which compression process */
#define M_SOF2  0xC2		/* Only SOF0-SOF2 are now in common use */
#define M_SOF3  0xC3
#define M_SOF5  0xC5		/* NB: codes C4 and CC are NOT SOF markers */
#define M_SOF6  0xC6
#define M_SOF7  0xC7
#define M_SOF9  0xC9
#define M_SOF10 0xCA
#define M_SOF11 0xCB
#define M_SOF13 0xCD
#define M_SOF14 0xCE
#define M_SOF15 0xCF
#define M_SOI   0xD8		/* Start Of Image (beginning of datastream) */
#define M_EOI   0xD9		/* End Of Image (end of datastream) */
#define M_DQT   0xDB		/* Quant tables */
#define M_SOS   0xDA		/* Start Of Scan (begins compressed data) */

#define JPEG_APP0       0xE0    /* JFIF header */

#define JPEG_APP1 (JPEG_APP0 + 1) 	/* XMP or EXIF */
#define JPEG_APP2 (JPEG_APP0 + 2) 	/* ICC profile */
#define JPEG_APP13 (JPEG_APP0 + 13) 	/* IPTC */
#define JPEG_APP14 (JPEG_APP0 + 14) 	/* adobe block */

#define M_COM   0xFE		/* COMment */


/*
 * Find the next JPEG marker and return its marker code.
 * We expect at least one FF byte, possibly more if the compressor used FFs
 * to pad the file.  (Padding FFs will NOT be replicated in the output file.)
 * There could also be non-FF garbage between markers.  The treatment of such
 * garbage is unspecified; we choose to skip over it but emit a warning msg.
 * NB: this routine must not be used after seeing SOS marker, since it will
 * not deal correctly with FF/00 sequences in the compressed image data...
 */

static int
next_marker (void)
{
  int c;
  int discarded_bytes = 0;

  /* Find 0xFF byte; count and skip any non-FFs. */
  c = read_1_byte();
  while (c != 0xFF) {
    discarded_bytes++;
    c = read_1_byte();
  }
  /* Get marker code byte, swallowing any duplicate FF bytes.  Extra FFs
   * are legal as pad bytes, so don't count them in discarded_bytes.
   */
  do {
    c = read_1_byte();
  } while (c == 0xFF);

  if (discarded_bytes != 0) {
    fprintf(stderr, "Warning: garbage data found in JPEG file\n");
  }

  return c;
}


/*
 * Read the initial marker, which should be SOI.
 * For a JFIF file, the first two bytes of the file should be literally
 * 0xFF M_SOI.  To be more general, we could use next_marker, but if the
 * input file weren't actually JPEG at all, next_marker might read the whole
 * file and then return a misleading error message...
 */

static int
first_marker (void)
{
  int c1, c2;

  c1 = NEXTBYTE();
  c2 = NEXTBYTE();
  if (c1 != 0xFF || c2 != M_SOI)
    ERREXIT("Not a JPEG file");
  return c2;
}


/*
 * Most types of marker are followed by a variable-length parameter segment.
 * This routine skips over the parameters for any marker we don't otherwise
 * want to process.
 * Note that we MUST skip the parameter segment explicitly in order not to
 * be fooled by 0xFF bytes that might appear within the parameter segment;
 * such bytes do NOT introduce new markers.
 */

static void
copy_variable (void)
/* Copy an unknown or uninteresting variable-length marker */
{
  unsigned int length;

  /* Get the marker parameter length count */
  length = read_2_bytes();
  printf( "copying %d bytes\n", length);
  write_2_bytes(length);
  /* Length includes itself, so must be at least 2 */
  if (length < 2)
    ERREXIT("Erroneous JPEG marker length");
  length -= 2;
  /* Copy the remaining bytes */
  while (length > 0) {
    write_1_byte(read_1_byte());
    length--;
  }
}

static void
skip_variable (void)
/* Skip over an unknown or uninteresting variable-length marker */
{
  unsigned int length;

  /* Get the marker parameter length count */
  length = read_2_bytes();
  printf( "skipping %d bytes\n", length);
  /* Length includes itself, so must be at least 2 */
  if (length < 2)
    ERREXIT("Erroneous JPEG marker length");
  length -= 2;
  /* Skip over the remaining bytes */
  while (length > 0) {
    (void) read_1_byte();
    length--;
  }
}


/*
 * Parse the marker stream until SOFn or EOI is seen;
 * copy data to output, but discard COM markers unless keep_COM is true.
 */

static int
copy_to_app2 (void)
{
  int marker;

  /* Expect SOI at start of file */
  if (first_marker() != M_SOI)
    ERREXIT("Expected SOI marker first");
  write_marker(M_SOI);

  for (;;) {
    marker = next_marker();
    printf( "marker = 0x%x\n", marker );
    switch (marker) {
	/* APP2 must come after APP0, APP1 and Adobe (APP14), but before
	 * everything else.
	 */
    	case JPEG_APP0:
    	case JPEG_APP0 + 1:
    	case JPEG_APP0 + 14:
		/* Copy and loop.
		 */
		write_marker(marker);
		copy_variable();
		break;

	case JPEG_APP0 + 2:		/* Existing app2, skip and don't copy */
		printf( "skipping existing APP2\n" );
		skip_variable();
		break;

	default:
		/* We've reached the first thing AFTER the spot where app2
		 * should go.
		 */
		return marker;
    }
  } /* end loop */
}


int
main (int argc, char **argv)
{
  char *profile;
  size_t profile_length;

  int marker;

  if (!(infile = fopen(argv[1], "rb"))) 
    ERREXIT("can't open input");

  if (!(outfile = fopen(argv[2], "wb"))) 
    ERREXIT("can't open output");

  if (!g_file_get_contents(argv[3], &profile, &profile_length, NULL))
    ERREXIT("can't open output");

  /* APP2 must be after the SOI and JFIF or Adobe markers, but before 
   * everything else.
   */


  /* Copy JPEG headers until SOFn marker, discarding any APP2 (icc profile).
   * we will insert the new APP2 just before SOFn.
   */
  marker = copy_to_app2();
  /* Insert the new APP2 marker */
  write_marker(JPEG_APP2);
  write_2_bytes(profile_length + 2 + 14);
  /* "ICC_PROFILE", null terminated */
  write_1_byte(0x49);
  write_1_byte(0x43);
  write_1_byte(0x43);
  write_1_byte(0x5F);
  write_1_byte(0x50);
  write_1_byte(0x52);
  write_1_byte(0x4F);
  write_1_byte(0x46);
  write_1_byte(0x49);
  write_1_byte(0x4C);
  write_1_byte(0x45);
  write_1_byte(0x0);
  /* profile marker number ... chunk 1 (numbering from 1) or 1 chunks in total
   */
  write_1_byte(0x1);
  write_1_byte(0x1);
  printf("inserting %ld bytes\n", profile_length);
  while (profile_length > 0) {
    write_1_byte(*profile++);
    profile_length--;
  }

  /* Duplicate the remainder of the source file.
   * Note that any COM markers occuring after SOF will not be touched.
   */
  write_marker(marker);
  copy_rest_of_file();

  return 0;
}