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
setup_read_icc_profile(j_decompress_ptr cinfo)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
marker_is_icc(jpeg_saved_marker_ptr marker)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
read_icc_profile(j_decompress_ptr cinfo,JOCTET ** icc_data_ptr,unsigned int * icc_data_len)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 }
185