media/libjpeg/jcicc.c

   1 /*
   2  * jcicc.c
   3  *
   4  * Copyright (C) 1997-1998, Thomas G. Lane, Todd Newman.
   5  * Copyright (C) 2017, D. R. Commander.
   6  * For conditions of distribution and use, see the accompanying README.ijg
   7  * file.
   8  *
   9  * This file provides code to write International Color Consortium (ICC) device
  10  * profiles embedded in JFIF JPEG image files.  The ICC has defined a standard
  11  * for including such data in JPEG "APP2" markers.  The code given here does
  12  * not know anything about the internal structure of the ICC profile data; it
  13  * just knows how to embed the profile data in a JPEG file while writing it.
  14  */
  15
  16 #define JPEG_INTERNALS
  17 #include "jinclude.h"
  18 #include "jpeglib.h"
  19 #include "jerror.h"
  20
  21
  22 /*
  23  * Since an ICC profile can be larger than the maximum size of a JPEG marker
  24  * (64K), we need provisions to split it into multiple markers.  The format
  25  * defined by the ICC specifies one or more APP2 markers containing the
  26  * following data:
  27  *      Identifying string      ASCII "ICC_PROFILE\0"  (12 bytes)
  28  *      Marker sequence number  1 for first APP2, 2 for next, etc (1 byte)
  29  *      Number of markers       Total number of APP2's used (1 byte)
  30  *      Profile data            (remainder of APP2 data)
  31  * Decoders should use the marker sequence numbers to reassemble the profile,
  32  * rather than assuming that the APP2 markers appear in the correct sequence.
  33  */
  34
  35 #define ICC_MARKER  (JPEG_APP0 + 2)     /* JPEG marker code for ICC */
  36 #define ICC_OVERHEAD_LEN  14            /* size of non-profile data in APP2 */
  37 #define MAX_BYTES_IN_MARKER  65533      /* maximum data len of a JPEG marker */
  38 #define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
  39
  40
  41 /*
  42  * This routine writes the given ICC profile data into a JPEG file.  It *must*
  43  * be called AFTER calling jpeg_start_compress() and BEFORE the first call to
  44  * jpeg_write_scanlines().  (This ordering ensures that the APP2 marker(s) will
  45  * appear after the SOI and JFIF or Adobe markers, but before all else.)
  46  */
  47
  48 GLOBAL(void)
  49 jpeg_write_icc_profile(j_compress_ptr cinfo, const JOCTET *icc_data_ptr,
  50                        unsigned int icc_data_len)
  51 {
  52   unsigned int num_markers;     /* total number of markers we'll write */
  53   int cur_marker = 1;           /* per spec, counting starts at 1 */
  54   unsigned int length;          /* number of bytes to write in this marker */
  55
  56   if (icc_data_ptr == NULL || icc_data_len == 0)
  57     ERREXIT(cinfo, JERR_BUFFER_SIZE);
  58   if (cinfo->global_state < CSTATE_SCANNING)
  59     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  60
  61   /* Calculate the number of markers we'll need, rounding up of course */
  62   num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER;
  63   if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len)
  64     num_markers++;
  65
  66   while (icc_data_len > 0) {
  67     /* length of profile to put in this marker */
  68     length = icc_data_len;
  69     if (length > MAX_DATA_BYTES_IN_MARKER)
  70       length = MAX_DATA_BYTES_IN_MARKER;
  71     icc_data_len -= length;
  72
  73     /* Write the JPEG marker header (APP2 code and marker length) */
  74     jpeg_write_m_header(cinfo, ICC_MARKER,
  75                         (unsigned int)(length + ICC_OVERHEAD_LEN));
  76
  77     /* Write the marker identifying string "ICC_PROFILE" (null-terminated).  We
  78      * code it in this less-than-transparent way so that the code works even if
  79      * the local character set is not ASCII.
  80      */
  81     jpeg_write_m_byte(cinfo, 0x49);
  82     jpeg_write_m_byte(cinfo, 0x43);
  83     jpeg_write_m_byte(cinfo, 0x43);
  84     jpeg_write_m_byte(cinfo, 0x5F);
  85     jpeg_write_m_byte(cinfo, 0x50);
  86     jpeg_write_m_byte(cinfo, 0x52);
  87     jpeg_write_m_byte(cinfo, 0x4F);
  88     jpeg_write_m_byte(cinfo, 0x46);
  89     jpeg_write_m_byte(cinfo, 0x49);
  90     jpeg_write_m_byte(cinfo, 0x4C);
  91     jpeg_write_m_byte(cinfo, 0x45);
  92     jpeg_write_m_byte(cinfo, 0x0);
  93
  94     /* Add the sequencing info */
  95     jpeg_write_m_byte(cinfo, cur_marker);
  96     jpeg_write_m_byte(cinfo, (int)num_markers);
  97
  98     /* Add the profile data */
  99     while (length--) {
 100       jpeg_write_m_byte(cinfo, *icc_data_ptr);
 101       icc_data_ptr++;
 102     }
 103     cur_marker++;
 104   }
 105 }