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 /* 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;

 }