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comparison: image/decoders/iccjpeg.c

image/decoders/iccjpeg.c

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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 * iccprofile.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 /*
29 * Since an ICC profile can be larger than the maximum size of a JPEG marker
30 * (64K), we need provisions to split it into multiple markers. The format
31 * defined by the ICC specifies one or more APP2 markers containing the
32 * following data:
33 * Identifying string ASCII "ICC_PROFILE\0" (12 bytes)
34 * Marker sequence number 1 for first APP2, 2 for next, etc (1 byte)
35 * Number of markers Total number of APP2's used (1 byte)
36 * Profile data (remainder of APP2 data)
37 * Decoders should use the marker sequence numbers to reassemble the profile,
38 * rather than assuming that the APP2 markers appear in the correct sequence.
39 */
40
41 #define ICC_MARKER (JPEG_APP0 + 2) /* JPEG marker code for ICC */
42 #define ICC_OVERHEAD_LEN 14 /* size of non-profile data in APP2 */
43 #define MAX_BYTES_IN_MARKER 65533 /* maximum data len of a JPEG marker */
44 #define MAX_DATA_BYTES_IN_MARKER (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
45
46 /*
47 * Prepare for reading an ICC profile
48 */
49
50 void
51 setup_read_icc_profile (j_decompress_ptr cinfo)
52 {
53 /* Tell the library to keep any APP2 data it may find */
54 jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
55 }
56
57
58 /*
59 * Handy subroutine to test whether a saved marker is an ICC profile marker.
60 */
61
62 static boolean
63 marker_is_icc (jpeg_saved_marker_ptr marker)
64 {
65 return
66 marker->marker == ICC_MARKER &&
67 marker->data_length >= ICC_OVERHEAD_LEN &&
68 /* verify the identifying string */
69 GETJOCTET(marker->data[0]) == 0x49 &&
70 GETJOCTET(marker->data[1]) == 0x43 &&
71 GETJOCTET(marker->data[2]) == 0x43 &&
72 GETJOCTET(marker->data[3]) == 0x5F &&
73 GETJOCTET(marker->data[4]) == 0x50 &&
74 GETJOCTET(marker->data[5]) == 0x52 &&
75 GETJOCTET(marker->data[6]) == 0x4F &&
76 GETJOCTET(marker->data[7]) == 0x46 &&
77 GETJOCTET(marker->data[8]) == 0x49 &&
78 GETJOCTET(marker->data[9]) == 0x4C &&
79 GETJOCTET(marker->data[10]) == 0x45 &&
80 GETJOCTET(marker->data[11]) == 0x0;
81 }
82
83
84 /*
85 * See if there was an ICC profile in the JPEG file being read;
86 * if so, reassemble and return the profile data.
87 *
88 * TRUE is returned if an ICC profile was found, FALSE if not.
89 * If TRUE is returned, *icc_data_ptr is set to point to the
90 * returned data, and *icc_data_len is set to its length.
91 *
92 * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
93 * and must be freed by the caller with free() when the caller no longer
94 * needs it. (Alternatively, we could write this routine to use the
95 * IJG library's memory allocator, so that the data would be freed implicitly
96 * at jpeg_finish_decompress() time. But it seems likely that many apps
97 * will prefer to have the data stick around after decompression finishes.)
98 *
99 * NOTE: if the file contains invalid ICC APP2 markers, we just silently
100 * return FALSE. You might want to issue an error message instead.
101 */
102
103 boolean
104 read_icc_profile (j_decompress_ptr cinfo,
105 JOCTET **icc_data_ptr,
106 unsigned int *icc_data_len)
107 {
108 jpeg_saved_marker_ptr marker;
109 int num_markers = 0;
110 int seq_no;
111 JOCTET *icc_data;
112 unsigned int total_length;
113 #define MAX_SEQ_NO 255 /* sufficient since marker numbers are bytes */
114 char marker_present[MAX_SEQ_NO+1]; /* 1 if marker found */
115 unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
116 unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */
117
118 *icc_data_ptr = NULL; /* avoid confusion if FALSE return */
119 *icc_data_len = 0;
120
121 /* This first pass over the saved markers discovers whether there are
122 * any ICC markers and verifies the consistency of the marker numbering.
123 */
124
125 for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
126 marker_present[seq_no] = 0;
127
128 for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
129 if (marker_is_icc(marker)) {
130 if (num_markers == 0)
131 num_markers = GETJOCTET(marker->data[13]);
132 else if (num_markers != GETJOCTET(marker->data[13]))
133 return FALSE; /* inconsistent num_markers fields */
134 seq_no = GETJOCTET(marker->data[12]);
135 if (seq_no <= 0 || seq_no > num_markers)
136 return FALSE; /* bogus sequence number */
137 if (marker_present[seq_no])
138 return FALSE; /* duplicate sequence numbers */
139 marker_present[seq_no] = 1;
140 data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
141 }
142 }
143
144 if (num_markers == 0)
145 return FALSE;
146
147 /* Check for missing markers, count total space needed,
148 * compute offset of each marker's part of the data.
149 */
150
151 total_length = 0;
152 for (seq_no = 1; seq_no <= num_markers; seq_no++) {
153 if (marker_present[seq_no] == 0)
154 return FALSE; /* missing sequence number */
155 data_offset[seq_no] = total_length;
156 total_length += data_length[seq_no];
157 }
158
159 if (total_length <= 0)
160 return FALSE; /* found only empty markers? */
161
162 /* Allocate space for assembled data */
163 icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
164 if (icc_data == NULL)
165 return FALSE; /* oops, out of memory */
166
167 /* and fill it in */
168 for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
169 if (marker_is_icc(marker)) {
170 JOCTET FAR *src_ptr;
171 JOCTET *dst_ptr;
172 unsigned int length;
173 seq_no = GETJOCTET(marker->data[12]);
174 dst_ptr = icc_data + data_offset[seq_no];
175 src_ptr = marker->data + ICC_OVERHEAD_LEN;
176 length = data_length[seq_no];
177 while (length--) {
178 *dst_ptr++ = *src_ptr++;
179 }
180 }
181 }
182
183 *icc_data_ptr = icc_data;
184 *icc_data_len = total_length;
185
186 return TRUE;
187 }

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