michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0:  * iccprofile.c
michael@0:  *
michael@0:  * This file provides code to read and write International Color Consortium
michael@0:  * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
michael@0:  * defined a standard format for including such data in JPEG "APP2" markers.
michael@0:  * The code given here does not know anything about the internal structure
michael@0:  * of the ICC profile data; it just knows how to put the profile data into
michael@0:  * a JPEG file being written, or get it back out when reading.
michael@0:  *
michael@0:  * This code depends on new features added to the IJG JPEG library as of
michael@0:  * IJG release 6b; it will not compile or work with older IJG versions.
michael@0:  *
michael@0:  * NOTE: this code would need surgery to work on 16-bit-int machines
michael@0:  * with ICC profiles exceeding 64K bytes in size.  If you need to do that,
michael@0:  * change all the "unsigned int" variables to "INT32".  You'll also need
michael@0:  * to find a malloc() replacement that can allocate more than 64K.
michael@0:  */
michael@0: 
michael@0: #include "iccjpeg.h"
michael@0: #include <stdlib.h>			/* define malloc() */
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Since an ICC profile can be larger than the maximum size of a JPEG marker
michael@0:  * (64K), we need provisions to split it into multiple markers.  The format
michael@0:  * defined by the ICC specifies one or more APP2 markers containing the
michael@0:  * following data:
michael@0:  *	Identifying string	ASCII "ICC_PROFILE\0"  (12 bytes)
michael@0:  *	Marker sequence number	1 for first APP2, 2 for next, etc (1 byte)
michael@0:  *	Number of markers	Total number of APP2's used (1 byte)
michael@0:  *      Profile data		(remainder of APP2 data)
michael@0:  * Decoders should use the marker sequence numbers to reassemble the profile,
michael@0:  * rather than assuming that the APP2 markers appear in the correct sequence.
michael@0:  */
michael@0: 
michael@0: #define ICC_MARKER  (JPEG_APP0 + 2)	/* JPEG marker code for ICC */
michael@0: #define ICC_OVERHEAD_LEN  14		/* size of non-profile data in APP2 */
michael@0: #define MAX_BYTES_IN_MARKER  65533	/* maximum data len of a JPEG marker */
michael@0: #define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
michael@0: 
michael@0: /*
michael@0:  * Prepare for reading an ICC profile
michael@0:  */
michael@0: 
michael@0: void
michael@0: setup_read_icc_profile (j_decompress_ptr cinfo)
michael@0: {
michael@0:   /* Tell the library to keep any APP2 data it may find */
michael@0:   jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
michael@0: }
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Handy subroutine to test whether a saved marker is an ICC profile marker.
michael@0:  */
michael@0: 
michael@0: static boolean
michael@0: marker_is_icc (jpeg_saved_marker_ptr marker)
michael@0: {
michael@0:   return
michael@0:     marker->marker == ICC_MARKER &&
michael@0:     marker->data_length >= ICC_OVERHEAD_LEN &&
michael@0:     /* verify the identifying string */
michael@0:     GETJOCTET(marker->data[0]) == 0x49 &&
michael@0:     GETJOCTET(marker->data[1]) == 0x43 &&
michael@0:     GETJOCTET(marker->data[2]) == 0x43 &&
michael@0:     GETJOCTET(marker->data[3]) == 0x5F &&
michael@0:     GETJOCTET(marker->data[4]) == 0x50 &&
michael@0:     GETJOCTET(marker->data[5]) == 0x52 &&
michael@0:     GETJOCTET(marker->data[6]) == 0x4F &&
michael@0:     GETJOCTET(marker->data[7]) == 0x46 &&
michael@0:     GETJOCTET(marker->data[8]) == 0x49 &&
michael@0:     GETJOCTET(marker->data[9]) == 0x4C &&
michael@0:     GETJOCTET(marker->data[10]) == 0x45 &&
michael@0:     GETJOCTET(marker->data[11]) == 0x0;
michael@0: }
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * See if there was an ICC profile in the JPEG file being read;
michael@0:  * if so, reassemble and return the profile data.
michael@0:  *
michael@0:  * TRUE is returned if an ICC profile was found, FALSE if not.
michael@0:  * If TRUE is returned, *icc_data_ptr is set to point to the
michael@0:  * returned data, and *icc_data_len is set to its length.
michael@0:  *
michael@0:  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
michael@0:  * and must be freed by the caller with free() when the caller no longer
michael@0:  * needs it.  (Alternatively, we could write this routine to use the
michael@0:  * IJG library's memory allocator, so that the data would be freed implicitly
michael@0:  * at jpeg_finish_decompress() time.  But it seems likely that many apps
michael@0:  * will prefer to have the data stick around after decompression finishes.)
michael@0:  *
michael@0:  * NOTE: if the file contains invalid ICC APP2 markers, we just silently
michael@0:  * return FALSE.  You might want to issue an error message instead.
michael@0:  */
michael@0: 
michael@0: boolean
michael@0: read_icc_profile (j_decompress_ptr cinfo,
michael@0: 		  JOCTET **icc_data_ptr,
michael@0: 		  unsigned int *icc_data_len)
michael@0: {
michael@0:   jpeg_saved_marker_ptr marker;
michael@0:   int num_markers = 0;
michael@0:   int seq_no;
michael@0:   JOCTET *icc_data;
michael@0:   unsigned int total_length;
michael@0: #define MAX_SEQ_NO  255		/* sufficient since marker numbers are bytes */
michael@0:   char marker_present[MAX_SEQ_NO+1];	  /* 1 if marker found */
michael@0:   unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
michael@0:   unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */
michael@0: 
michael@0:   *icc_data_ptr = NULL;		/* avoid confusion if FALSE return */
michael@0:   *icc_data_len = 0;
michael@0: 
michael@0:   /* This first pass over the saved markers discovers whether there are
michael@0:    * any ICC markers and verifies the consistency of the marker numbering.
michael@0:    */
michael@0: 
michael@0:   for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
michael@0:     marker_present[seq_no] = 0;
michael@0: 
michael@0:   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
michael@0:     if (marker_is_icc(marker)) {
michael@0:       if (num_markers == 0)
michael@0: 	num_markers = GETJOCTET(marker->data[13]);
michael@0:       else if (num_markers != GETJOCTET(marker->data[13]))
michael@0: 	return FALSE;		/* inconsistent num_markers fields */
michael@0:       seq_no = GETJOCTET(marker->data[12]);
michael@0:       if (seq_no <= 0 || seq_no > num_markers)
michael@0: 	return FALSE;		/* bogus sequence number */
michael@0:       if (marker_present[seq_no])
michael@0: 	return FALSE;		/* duplicate sequence numbers */
michael@0:       marker_present[seq_no] = 1;
michael@0:       data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (num_markers == 0)
michael@0:     return FALSE;
michael@0: 
michael@0:   /* Check for missing markers, count total space needed,
michael@0:    * compute offset of each marker's part of the data.
michael@0:    */
michael@0: 
michael@0:   total_length = 0;
michael@0:   for (seq_no = 1; seq_no <= num_markers; seq_no++) {
michael@0:     if (marker_present[seq_no] == 0)
michael@0:       return FALSE;		/* missing sequence number */
michael@0:     data_offset[seq_no] = total_length;
michael@0:     total_length += data_length[seq_no];
michael@0:   }
michael@0: 
michael@0:   if (total_length <= 0)
michael@0:     return FALSE;		/* found only empty markers? */
michael@0: 
michael@0:   /* Allocate space for assembled data */
michael@0:   icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
michael@0:   if (icc_data == NULL)
michael@0:     return FALSE;		/* oops, out of memory */
michael@0: 
michael@0:   /* and fill it in */
michael@0:   for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
michael@0:     if (marker_is_icc(marker)) {
michael@0:       JOCTET FAR *src_ptr;
michael@0:       JOCTET *dst_ptr;
michael@0:       unsigned int length;
michael@0:       seq_no = GETJOCTET(marker->data[12]);
michael@0:       dst_ptr = icc_data + data_offset[seq_no];
michael@0:       src_ptr = marker->data + ICC_OVERHEAD_LEN;
michael@0:       length = data_length[seq_no];
michael@0:       while (length--) {
michael@0: 	*dst_ptr++ = *src_ptr++;
michael@0:       }
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   *icc_data_ptr = icc_data;
michael@0:   *icc_data_len = total_length;
michael@0: 
michael@0:   return TRUE;
michael@0: }