image/decoders/iccjpeg.c

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 /*
   6  * iccjpeg.c
   7  *
   8  * This file provides code to read and write International Color Consortium
   9  * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
  10  * defined a standard format for including such data in JPEG "APP2" markers.
  11  * The code given here does not know anything about the internal structure
  12  * of the ICC profile data; it just knows how to put the profile data into
  13  * a JPEG file being written, or get it back out when reading.
  14  *
  15  * This code depends on new features added to the IJG JPEG library as of
  16  * IJG release 6b; it will not compile or work with older IJG versions.
  17  *
  18  * NOTE: this code would need surgery to work on 16-bit-int machines
  19  * with ICC profiles exceeding 64K bytes in size.  If you need to do that,
  20  * change all the "unsigned int" variables to "INT32".  You'll also need
  21  * to find a malloc() replacement that can allocate more than 64K.
  22  */
  23
  24 #include "iccjpeg.h"
  25 #include <stdlib.h> /* define malloc() */
  26
  27 /*
  28  * Since an ICC profile can be larger than the maximum size of a JPEG marker
  29  * (64K), we need provisions to split it into multiple markers.  The format
  30  * defined by the ICC specifies one or more APP2 markers containing the
  31  * following data:
  32  *      Identifying string      ASCII "ICC_PROFILE\0"  (12 bytes)
  33  *      Marker sequence number  1 for first APP2, 2 for next, etc (1 byte)
  34  *      Number of markers       Total number of APP2's used (1 byte)
  35  *      Profile data            (remainder of APP2 data)
  36  * Decoders should use the marker sequence numbers to reassemble the profile,
  37  * rather than assuming that the APP2 markers appear in the correct sequence.
  38  */
  39
  40 #define ICC_MARKER (JPEG_APP0 + 2) /* JPEG marker code for ICC */
  41 #define ICC_OVERHEAD_LEN 14        /* size of non-profile data in APP2 */
  42 #define MAX_BYTES_IN_MARKER 65533  /* maximum data len of a JPEG marker */
  43 #define MAX_DATA_BYTES_IN_MARKER (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
  44
  45 /*
  46  * Prepare for reading an ICC profile
  47  */
  48
  49 void setup_read_icc_profile(j_decompress_ptr cinfo) {
  50   /* Tell the library to keep any APP2 data it may find */
  51   jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
  52 }
  53
  54 /*
  55  * Handy subroutine to test whether a saved marker is an ICC profile marker.
  56  */
  57
  58 static boolean marker_is_icc(jpeg_saved_marker_ptr marker) {
  59   return marker->marker == ICC_MARKER &&
  60          marker->data_length >= ICC_OVERHEAD_LEN &&
  61          /* verify the identifying string */
  62          GETJOCTET(marker->data[0]) == 0x49 &&
  63          GETJOCTET(marker->data[1]) == 0x43 &&
  64          GETJOCTET(marker->data[2]) == 0x43 &&
  65          GETJOCTET(marker->data[3]) == 0x5F &&
  66          GETJOCTET(marker->data[4]) == 0x50 &&
  67          GETJOCTET(marker->data[5]) == 0x52 &&
  68          GETJOCTET(marker->data[6]) == 0x4F &&
  69          GETJOCTET(marker->data[7]) == 0x46 &&
  70          GETJOCTET(marker->data[8]) == 0x49 &&
  71          GETJOCTET(marker->data[9]) == 0x4C &&
  72          GETJOCTET(marker->data[10]) == 0x45 &&
  73          GETJOCTET(marker->data[11]) == 0x0;
  74 }
  75
  76 /*
  77  * See if there was an ICC profile in the JPEG file being read;
  78  * if so, reassemble and return the profile data.
  79  *
  80  * TRUE is returned if an ICC profile was found, FALSE if not.
  81  * If TRUE is returned, *icc_data_ptr is set to point to the
  82  * returned data, and *icc_data_len is set to its length.
  83  *
  84  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
  85  * and must be freed by the caller with free() when the caller no longer
  86  * needs it.  (Alternatively, we could write this routine to use the
  87  * IJG library's memory allocator, so that the data would be freed implicitly
  88  * at jpeg_finish_decompress() time.  But it seems likely that many apps
  89  * will prefer to have the data stick around after decompression finishes.)
  90  *
  91  * NOTE: if the file contains invalid ICC APP2 markers, we just silently
  92  * return FALSE.  You might want to issue an error message instead.
  93  */
  94
  95 boolean read_icc_profile(j_decompress_ptr cinfo, JOCTET** icc_data_ptr,
  96                          unsigned int* icc_data_len) {
  97   jpeg_saved_marker_ptr marker;
  98   int num_markers = 0;
  99   int seq_no;
 100   JOCTET* icc_data;
 101   unsigned int total_length;
 102 #define MAX_SEQ_NO 255 /* sufficient since marker numbers are bytes */
 103   char marker_present[MAX_SEQ_NO + 1];      /* 1 if marker found */
 104   unsigned int data_length[MAX_SEQ_NO + 1]; /* size of profile data in marker */
 105   unsigned int data_offset[MAX_SEQ_NO + 1]; /* offset for data in marker */
 106
 107   *icc_data_ptr = NULL; /* avoid confusion if FALSE return */
 108   *icc_data_len = 0;
 109
 110   /* This first pass over the saved markers discovers whether there are
 111    * any ICC markers and verifies the consistency of the marker numbering.
 112    */
 113
 114   for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++) {
 115     marker_present[seq_no] = 0;
 116   }
 117
 118   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
 119     if (marker_is_icc(marker)) {
 120       if (num_markers == 0) {
 121         num_markers = GETJOCTET(marker->data[13]);
 122       } else if (num_markers != GETJOCTET(marker->data[13])) {
 123         return FALSE; /* inconsistent num_markers fields */
 124       }
 125       seq_no = GETJOCTET(marker->data[12]);
 126       if (seq_no <= 0 || seq_no > num_markers) {
 127         return FALSE; /* bogus sequence number */
 128       }
 129       if (marker_present[seq_no]) {
 130         return FALSE; /* duplicate sequence numbers */
 131       }
 132       marker_present[seq_no] = 1;
 133       data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
 134     }
 135   }
 136
 137   if (num_markers == 0) {
 138     return FALSE;
 139   }
 140
 141   /* Check for missing markers, count total space needed,
 142    * compute offset of each marker's part of the data.
 143    */
 144
 145   total_length = 0;
 146   for (seq_no = 1; seq_no <= num_markers; seq_no++) {
 147     if (marker_present[seq_no] == 0) {
 148       return FALSE; /* missing sequence number */
 149     }
 150     data_offset[seq_no] = total_length;
 151     total_length += data_length[seq_no];
 152   }
 153
 154   if (total_length <= 0) {
 155     return FALSE; /* found only empty markers? */
 156   }
 157
 158   /* Allocate space for assembled data */
 159   icc_data = (JOCTET*)malloc(total_length * sizeof(JOCTET));
 160   if (icc_data == NULL) {
 161     return FALSE; /* oops, out of memory */
 162   }
 163
 164   /* and fill it in */
 165   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
 166     if (marker_is_icc(marker)) {
 167       JOCTET FAR* src_ptr;
 168       JOCTET* dst_ptr;
 169       unsigned int length;
 170       seq_no = GETJOCTET(marker->data[12]);
 171       dst_ptr = icc_data + data_offset[seq_no];
 172       src_ptr = marker->data + ICC_OVERHEAD_LEN;
 173       length = data_length[seq_no];
 174       while (length--) {
 175         *dst_ptr++ = *src_ptr++;
 176       }
 177     }
 178   }
 179
 180   *icc_data_ptr = icc_data;
 181   *icc_data_len = total_length;
 182
 183   return TRUE;
 184 }