DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * iccprofile.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)

/*
 * 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;
}