third_party/iccjpeg/iccjpeg.c

   1 /*
   2  * iccprofile.c
   3  *
   4  * This file provides code to read and write International Color Consortium
   5  * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
   6  * defined a standard format for including such data in JPEG "APP2" markers.
   7  * The code given here does not know anything about the internal structure
   8  * of the ICC profile data; it just knows how to put the profile data into
   9  * a JPEG file being written, or get it back out when reading.
  10  *
  11  * This code depends on new features added to the IJG JPEG library as of
  12  * IJG release 6b; it will not compile or work with older IJG versions.
  13  *
  14  * NOTE: this code would need surgery to work on 16-bit-int machines
  15  * with ICC profiles exceeding 64K bytes in size.  If you need to do that,
  16  * change all the "unsigned int" variables to "INT32".  You'll also need
  17  * to find a malloc() replacement that can allocate more than 64K.
  18  */
  19
  20 #include "iccjpeg.h"
  21 #include <stdlib.h>                     /* define malloc() */
  22
  23
  24 /*
  25  * Since an ICC profile can be larger than the maximum size of a JPEG marker
  26  * (64K), we need provisions to split it into multiple markers.  The format
  27  * defined by the ICC specifies one or more APP2 markers containing the
  28  * following data:
  29  *      Identifying string      ASCII "ICC_PROFILE\0"  (12 bytes)
  30  *      Marker sequence number  1 for first APP2, 2 for next, etc (1 byte)
  31  *      Number of markers       Total number of APP2's used (1 byte)
  32  *      Profile data            (remainder of APP2 data)
  33  * Decoders should use the marker sequence numbers to reassemble the profile,
  34  * rather than assuming that the APP2 markers appear in the correct sequence.
  35  */
  36
  37 #define ICC_MARKER  (JPEG_APP0 + 2)     /* JPEG marker code for ICC */
  38 #define ICC_OVERHEAD_LEN  14            /* size of non-profile data in APP2 */
  39 #define MAX_BYTES_IN_MARKER  65533      /* maximum data len of a JPEG marker */
  40 #define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
  41
  42
  43 /*
  44  * This routine writes the given ICC profile data into a JPEG file.
  45  * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
  46  * the first call to jpeg_write_scanlines().
  47  * (This ordering ensures that the APP2 marker(s) will appear after the
  48  * SOI and JFIF or Adobe markers, but before all else.)
  49  */
  50
  51 void
  52 write_icc_profile (j_compress_ptr cinfo,
  53                    const JOCTET *icc_data_ptr,
  54                    unsigned int icc_data_len)
  55 {
  56   unsigned int num_markers;     /* total number of markers we'll write */
  57   int cur_marker = 1;           /* per spec, counting starts at 1 */
  58   unsigned int length;          /* number of bytes to write in this marker */
  59
  60   /* Calculate the number of markers we'll need, rounding up of course */
  61   num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER;
  62   if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len)
  63     num_markers++;
  64
  65   while (icc_data_len > 0) {
  66     /* length of profile to put in this marker */
  67     length = icc_data_len;
  68     if (length > MAX_DATA_BYTES_IN_MARKER)
  69       length = MAX_DATA_BYTES_IN_MARKER;
  70     icc_data_len -= length;
  71
  72     /* Write the JPEG marker header (APP2 code and marker length) */
  73     jpeg_write_m_header(cinfo, ICC_MARKER,
  74                         (unsigned int) (length + ICC_OVERHEAD_LEN));
  75
  76     /* Write the marker identifying string "ICC_PROFILE" (null-terminated).
  77      * We code it in this less-than-transparent way so that the code works
  78      * even if the local character set is not ASCII.
  79      */
  80     jpeg_write_m_byte(cinfo, 0x49);
  81     jpeg_write_m_byte(cinfo, 0x43);
  82     jpeg_write_m_byte(cinfo, 0x43);
  83     jpeg_write_m_byte(cinfo, 0x5F);
  84     jpeg_write_m_byte(cinfo, 0x50);
  85     jpeg_write_m_byte(cinfo, 0x52);
  86     jpeg_write_m_byte(cinfo, 0x4F);
  87     jpeg_write_m_byte(cinfo, 0x46);
  88     jpeg_write_m_byte(cinfo, 0x49);
  89     jpeg_write_m_byte(cinfo, 0x4C);
  90     jpeg_write_m_byte(cinfo, 0x45);
  91     jpeg_write_m_byte(cinfo, 0x0);
  92
  93     /* Add the sequencing info */
  94     jpeg_write_m_byte(cinfo, cur_marker);
  95     jpeg_write_m_byte(cinfo, (int) num_markers);
  96
  97     /* Add the profile data */
  98     while (length--) {
  99       jpeg_write_m_byte(cinfo, *icc_data_ptr);
 100       icc_data_ptr++;
 101     }
 102     cur_marker++;
 103   }
 104 }
 105
 106
 107 /*
 108  * Prepare for reading an ICC profile
 109  */
 110
 111 void
 112 setup_read_icc_profile (j_decompress_ptr cinfo)
 113 {
 114   /* Tell the library to keep any APP2 data it may find */
 115   jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
 116 }
 117
 118
 119 /*
 120  * Handy subroutine to test whether a saved marker is an ICC profile marker.
 121  */
 122
 123 static boolean
 124 marker_is_icc (jpeg_saved_marker_ptr marker)
 125 {
 126   return
 127     marker->marker == ICC_MARKER &&
 128     marker->data_length >= ICC_OVERHEAD_LEN &&
 129     /* verify the identifying string */
 130     GETJOCTET(marker->data[0]) == 0x49 &&
 131     GETJOCTET(marker->data[1]) == 0x43 &&
 132     GETJOCTET(marker->data[2]) == 0x43 &&
 133     GETJOCTET(marker->data[3]) == 0x5F &&
 134     GETJOCTET(marker->data[4]) == 0x50 &&
 135     GETJOCTET(marker->data[5]) == 0x52 &&
 136     GETJOCTET(marker->data[6]) == 0x4F &&
 137     GETJOCTET(marker->data[7]) == 0x46 &&
 138     GETJOCTET(marker->data[8]) == 0x49 &&
 139     GETJOCTET(marker->data[9]) == 0x4C &&
 140     GETJOCTET(marker->data[10]) == 0x45 &&
 141     GETJOCTET(marker->data[11]) == 0x0;
 142 }
 143
 144
 145 /*
 146  * See if there was an ICC profile in the JPEG file being read;
 147  * if so, reassemble and return the profile data.
 148  *
 149  * TRUE is returned if an ICC profile was found, FALSE if not.
 150  * If TRUE is returned, *icc_data_ptr is set to point to the
 151  * returned data, and *icc_data_len is set to its length.
 152  *
 153  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
 154  * and must be freed by the caller with free() when the caller no longer
 155  * needs it.  (Alternatively, we could write this routine to use the
 156  * IJG library's memory allocator, so that the data would be freed implicitly
 157  * at jpeg_finish_decompress() time.  But it seems likely that many apps
 158  * will prefer to have the data stick around after decompression finishes.)
 159  *
 160  * NOTE: if the file contains invalid ICC APP2 markers, we just silently
 161  * return FALSE.  You might want to issue an error message instead.
 162  */
 163
 164 boolean
 165 read_icc_profile (j_decompress_ptr cinfo,
 166                   JOCTET **icc_data_ptr,
 167                   unsigned int *icc_data_len)
 168 {
 169   jpeg_saved_marker_ptr marker;
 170   int num_markers = 0;
 171   int seq_no;
 172   JOCTET *icc_data;
 173   unsigned int total_length;
 174 #define MAX_SEQ_NO  255         /* sufficient since marker numbers are bytes */
 175   char marker_present[MAX_SEQ_NO+1];      /* 1 if marker found */
 176   unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
 177   unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */
 178
 179   *icc_data_ptr = NULL;         /* avoid confusion if FALSE return */
 180   *icc_data_len = 0;
 181
 182   /* This first pass over the saved markers discovers whether there are
 183    * any ICC markers and verifies the consistency of the marker numbering.
 184    */
 185
 186   for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
 187     marker_present[seq_no] = 0;
 188
 189   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
 190     if (marker_is_icc(marker)) {
 191       if (num_markers == 0)
 192         num_markers = GETJOCTET(marker->data[13]);
 193       else if (num_markers != GETJOCTET(marker->data[13]))
 194         return FALSE;           /* inconsistent num_markers fields */
 195       seq_no = GETJOCTET(marker->data[12]);
 196       if (seq_no <= 0 || seq_no > num_markers)
 197         return FALSE;           /* bogus sequence number */
 198       if (marker_present[seq_no])
 199         return FALSE;           /* duplicate sequence numbers */
 200       marker_present[seq_no] = 1;
 201       data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
 202     }
 203   }
 204
 205   if (num_markers == 0)
 206     return FALSE;
 207
 208   /* Check for missing markers, count total space needed,
 209    * compute offset of each marker's part of the data.
 210    */
 211
 212   total_length = 0;
 213   for (seq_no = 1; seq_no <= num_markers; seq_no++) {
 214     if (marker_present[seq_no] == 0)
 215       return FALSE;             /* missing sequence number */
 216     data_offset[seq_no] = total_length;
 217     total_length += data_length[seq_no];
 218   }
 219
 220   if (total_length <= 0)
 221     return FALSE;               /* found only empty markers? */
 222
 223   /* Allocate space for assembled data */
 224   icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
 225   if (icc_data == NULL)
 226     return FALSE;               /* oops, out of memory */
 227
 228   /* and fill it in */
 229   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
 230     if (marker_is_icc(marker)) {
 231       JOCTET FAR *src_ptr;
 232       JOCTET *dst_ptr;
 233       unsigned int length;
 234       seq_no = GETJOCTET(marker->data[12]);
 235       dst_ptr = icc_data + data_offset[seq_no];
 236       src_ptr = marker->data + ICC_OVERHEAD_LEN;
 237       length = data_length[seq_no];
 238       while (length--) {
 239         *dst_ptr++ = *src_ptr++;
 240       }
 241     }
 242   }
 243
 244   *icc_data_ptr = icc_data;
 245   *icc_data_len = total_length;
 246
 247   return TRUE;
 248 }