
/*

Little CMS
Copyright (c) 1998-2010 Marti Maria Saguer

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and as
sociated documentation files (the "Software"), to deal in the Software without restriction, includin
g without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subj
ect to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial
 portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NO
T LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABI
LITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WIT
H THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

*/

/*
 * iccjpeg.c
 *
 * This file provides code to read and write International Color Consortium
 * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
 * defined a standard format for including such data in JPEG "APP2" markers.
 * The code given here does not know anything about the internal structure
 * of the ICC profile data; it just knows how to put the profile data into
 * a JPEG file being written, or get it back out when reading.
 *
 * This code depends on new features added to the IJG JPEG library as of
 * IJG release 6b; it will not compile or work with older IJG versions.
 *
 * NOTE: this code would need surgery to work on 16-bit-int machines
 * with ICC profiles exceeding 64K bytes in size.  If you need to do that,
 * change all the "unsigned int" variables to "INT32".  You'll also need
 * to find a malloc() replacement that can allocate more than 64K.
 */

#include "iccjpeg.h"
#include <stdlib.h>			/* define malloc() */


/*
 * Since an ICC profile can be larger than the maximum size of a JPEG marker
 * (64K), we need provisions to split it into multiple markers.  The format
 * defined by the ICC specifies one or more APP2 markers containing the
 * following data:
 *	Identifying string	ASCII "ICC_PROFILE\0"  (12 bytes)
 *	Marker sequence number	1 for first APP2, 2 for next, etc (1 byte)
 *	Number of markers	Total number of APP2's used (1 byte)
 *      Profile data		(remainder of APP2 data)
 * Decoders should use the marker sequence numbers to reassemble the profile,
 * rather than assuming that the APP2 markers appear in the correct sequence.
 */

#define ICC_MARKER  (JPEG_APP0 + 2)	/* JPEG marker code for ICC */
#define ICC_OVERHEAD_LEN  14		/* size of non-profile data in APP2 */
#define MAX_BYTES_IN_MARKER  65533	/* maximum data len of a JPEG marker */
#define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)


/*
 * This routine writes the given ICC profile data into a JPEG file.
 * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
 * the first call to jpeg_write_scanlines().
 * (This ordering ensures that the APP2 marker(s) will appear after the
 * SOI and JFIF or Adobe markers, but before all else.)
 */

void
write_icc_profile (j_compress_ptr cinfo,
		   const JOCTET *icc_data_ptr,
		   unsigned int icc_data_len)
{
  unsigned int num_markers;	/* total number of markers we'll write */
  int cur_marker = 1;		/* per spec, counting starts at 1 */
  unsigned int length;		/* number of bytes to write in this marker */

  /* Calculate the number of markers we'll need, rounding up of course */
  num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER;
  if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len)
    num_markers++;

  while (icc_data_len > 0) {
    /* length of profile to put in this marker */
    length = icc_data_len;
    if (length > MAX_DATA_BYTES_IN_MARKER)
      length = MAX_DATA_BYTES_IN_MARKER;
    icc_data_len -= length;

    /* Write the JPEG marker header (APP2 code and marker length) */
    jpeg_write_m_header(cinfo, ICC_MARKER,
			(unsigned int) (length + ICC_OVERHEAD_LEN));

    /* Write the marker identifying string "ICC_PROFILE" (null-terminated).
     * We code it in this less-than-transparent way so that the code works
     * even if the local character set is not ASCII.
     */
    jpeg_write_m_byte(cinfo, 0x49);
    jpeg_write_m_byte(cinfo, 0x43);
    jpeg_write_m_byte(cinfo, 0x43);
    jpeg_write_m_byte(cinfo, 0x5F);
    jpeg_write_m_byte(cinfo, 0x50);
    jpeg_write_m_byte(cinfo, 0x52);
    jpeg_write_m_byte(cinfo, 0x4F);
    jpeg_write_m_byte(cinfo, 0x46);
    jpeg_write_m_byte(cinfo, 0x49);
    jpeg_write_m_byte(cinfo, 0x4C);
    jpeg_write_m_byte(cinfo, 0x45);
    jpeg_write_m_byte(cinfo, 0x0);

    /* Add the sequencing info */
    jpeg_write_m_byte(cinfo, cur_marker);
    jpeg_write_m_byte(cinfo, (int) num_markers);

    /* Add the profile data */
    while (length--) {
      jpeg_write_m_byte(cinfo, *icc_data_ptr);
      icc_data_ptr++;
    }
    cur_marker++;
  }
}


/*
 * Prepare for reading an ICC profile
 */

void
setup_read_icc_profile (j_decompress_ptr cinfo)
{
  /* Tell the library to keep any APP2 data it may find */
  jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
}


/*
 * Handy subroutine to test whether a saved marker is an ICC profile marker.
 */

static boolean
marker_is_icc (jpeg_saved_marker_ptr marker)
{
  return
    marker->marker == ICC_MARKER &&
    marker->data_length >= ICC_OVERHEAD_LEN &&
    /* verify the identifying string */
    GETJOCTET(marker->data[0]) == 0x49 &&
    GETJOCTET(marker->data[1]) == 0x43 &&
    GETJOCTET(marker->data[2]) == 0x43 &&
    GETJOCTET(marker->data[3]) == 0x5F &&
    GETJOCTET(marker->data[4]) == 0x50 &&
    GETJOCTET(marker->data[5]) == 0x52 &&
    GETJOCTET(marker->data[6]) == 0x4F &&
    GETJOCTET(marker->data[7]) == 0x46 &&
    GETJOCTET(marker->data[8]) == 0x49 &&
    GETJOCTET(marker->data[9]) == 0x4C &&
    GETJOCTET(marker->data[10]) == 0x45 &&
    GETJOCTET(marker->data[11]) == 0x0;
}


/*
 * See if there was an ICC profile in the JPEG file being read;
 * if so, reassemble and return the profile data.
 *
 * TRUE is returned if an ICC profile was found, FALSE if not.
 * If TRUE is returned, *icc_data_ptr is set to point to the
 * returned data, and *icc_data_len is set to its length.
 *
 * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
 * and must be freed by the caller with free() when the caller no longer
 * needs it.  (Alternatively, we could write this routine to use the
 * IJG library's memory allocator, so that the data would be freed implicitly
 * at jpeg_finish_decompress() time.  But it seems likely that many apps
 * will prefer to have the data stick around after decompression finishes.)
 *
 * NOTE: if the file contains invalid ICC APP2 markers, we just silently
 * return FALSE.  You might want to issue an error message instead.
 */

boolean
read_icc_profile (j_decompress_ptr cinfo,
		  JOCTET **icc_data_ptr,
		  unsigned int *icc_data_len)
{
  jpeg_saved_marker_ptr marker;
  int num_markers = 0;
  int seq_no;
  JOCTET *icc_data;
  unsigned int total_length;
#define MAX_SEQ_NO  255		/* sufficient since marker numbers are bytes */
  char marker_present[MAX_SEQ_NO+1];	  /* 1 if marker found */
  unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
  unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */

  *icc_data_ptr = NULL;		/* avoid confusion if FALSE return */
  *icc_data_len = 0;

  /* This first pass over the saved markers discovers whether there are
   * any ICC markers and verifies the consistency of the marker numbering.
   */

  for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
    marker_present[seq_no] = 0;

  for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
    if (marker_is_icc(marker)) {
      if (num_markers == 0)
	num_markers = GETJOCTET(marker->data[13]);
      else if (num_markers != GETJOCTET(marker->data[13]))
	return FALSE;		/* inconsistent num_markers fields */
      seq_no = GETJOCTET(marker->data[12]);
      if (seq_no <= 0 || seq_no > num_markers)
	return FALSE;		/* bogus sequence number */
      if (marker_present[seq_no])
	return FALSE;		/* duplicate sequence numbers */
      marker_present[seq_no] = 1;
      data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
    }
  }

  if (num_markers == 0)
    return FALSE;

  /* Check for missing markers, count total space needed,
   * compute offset of each marker's part of the data.
   */

  total_length = 0;
  for (seq_no = 1; seq_no <= num_markers; seq_no++) {
    if (marker_present[seq_no] == 0)
      return FALSE;		/* missing sequence number */
    data_offset[seq_no] = total_length;
    total_length += data_length[seq_no];
  }

  if (total_length <= 0)
    return FALSE;		/* found only empty markers? */

  /* Allocate space for assembled data */
  icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
  if (icc_data == NULL)
    return FALSE;		/* oops, out of memory */

  /* and fill it in */
  for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
    if (marker_is_icc(marker)) {
      JOCTET FAR *src_ptr;
      JOCTET *dst_ptr;
      unsigned int length;
      seq_no = GETJOCTET(marker->data[12]);
      dst_ptr = icc_data + data_offset[seq_no];
      src_ptr = marker->data + ICC_OVERHEAD_LEN;
      length = data_length[seq_no];
      while (length--) {
	*dst_ptr++ = *src_ptr++;
      }
    }
  }

  *icc_data_ptr = icc_data;
  *icc_data_len = total_length;

  return TRUE;
}
