1 : /*
2 : * iccprofile.c
3 : *
4 : * This file provides code to read and write International Color Consortium
5 : * (ICC) device profiles embedded in JFIF JPEG image files. The ICC has
6 : * defined a standard format for including such data in JPEG "APP2" markers.
7 : * The code given here does not know anything about the internal structure
8 : * of the ICC profile data; it just knows how to put the profile data into
9 : * a JPEG file being written, or get it back out when reading.
10 : *
11 : * This code depends on new features added to the IJG JPEG library as of
12 : * IJG release 6b; it will not compile or work with older IJG versions.
13 : *
14 : * NOTE: this code would need surgery to work on 16-bit-int machines
15 : * with ICC profiles exceeding 64K bytes in size. If you need to do that,
16 : * change all the "unsigned int" variables to "INT32". You'll also need
17 : * to find a malloc() replacement that can allocate more than 64K.
18 : */
19 :
20 : #include "iccjpeg.h"
21 : #include <stdlib.h> /* define malloc() */
22 :
23 :
24 : /*
25 : * Since an ICC profile can be larger than the maximum size of a JPEG marker
26 : * (64K), we need provisions to split it into multiple markers. The format
27 : * defined by the ICC specifies one or more APP2 markers containing the
28 : * following data:
29 : * Identifying string ASCII "ICC_PROFILE\0" (12 bytes)
30 : * Marker sequence number 1 for first APP2, 2 for next, etc (1 byte)
31 : * Number of markers Total number of APP2's used (1 byte)
32 : * Profile data (remainder of APP2 data)
33 : * Decoders should use the marker sequence numbers to reassemble the profile,
34 : * rather than assuming that the APP2 markers appear in the correct sequence.
35 : */
36 :
37 : #define ICC_MARKER (JPEG_APP0 + 2) /* JPEG marker code for ICC */
38 : #define ICC_OVERHEAD_LEN 14 /* size of non-profile data in APP2 */
39 : #define MAX_BYTES_IN_MARKER 65533 /* maximum data len of a JPEG marker */
40 : #define MAX_DATA_BYTES_IN_MARKER (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
41 :
42 : /*
43 : * Prepare for reading an ICC profile
44 : */
45 :
46 : void
47 0 : setup_read_icc_profile (j_decompress_ptr cinfo)
48 : {
49 : /* Tell the library to keep any APP2 data it may find */
50 0 : jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
51 0 : }
52 :
53 :
54 : /*
55 : * Handy subroutine to test whether a saved marker is an ICC profile marker.
56 : */
57 :
58 : static boolean
59 10 : marker_is_icc (jpeg_saved_marker_ptr marker)
60 : {
61 10 : return
62 10 : marker->marker == ICC_MARKER &&
63 0 : marker->data_length >= ICC_OVERHEAD_LEN &&
64 : /* verify the identifying string */
65 0 : GETJOCTET(marker->data[0]) == 0x49 &&
66 0 : GETJOCTET(marker->data[1]) == 0x43 &&
67 0 : GETJOCTET(marker->data[2]) == 0x43 &&
68 0 : GETJOCTET(marker->data[3]) == 0x5F &&
69 0 : GETJOCTET(marker->data[4]) == 0x50 &&
70 0 : GETJOCTET(marker->data[5]) == 0x52 &&
71 0 : GETJOCTET(marker->data[6]) == 0x4F &&
72 0 : GETJOCTET(marker->data[7]) == 0x46 &&
73 0 : GETJOCTET(marker->data[8]) == 0x49 &&
74 0 : GETJOCTET(marker->data[9]) == 0x4C &&
75 0 : GETJOCTET(marker->data[10]) == 0x45 &&
76 0 : GETJOCTET(marker->data[11]) == 0x0;
77 : }
78 :
79 :
80 : /*
81 : * See if there was an ICC profile in the JPEG file being read;
82 : * if so, reassemble and return the profile data.
83 : *
84 : * TRUE is returned if an ICC profile was found, FALSE if not.
85 : * If TRUE is returned, *icc_data_ptr is set to point to the
86 : * returned data, and *icc_data_len is set to its length.
87 : *
88 : * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
89 : * and must be freed by the caller with free() when the caller no longer
90 : * needs it. (Alternatively, we could write this routine to use the
91 : * IJG library's memory allocator, so that the data would be freed implicitly
92 : * at jpeg_finish_decompress() time. But it seems likely that many apps
93 : * will prefer to have the data stick around after decompression finishes.)
94 : *
95 : * NOTE: if the file contains invalid ICC APP2 markers, we just silently
96 : * return FALSE. You might want to issue an error message instead.
97 : */
98 :
99 : boolean
100 5 : read_icc_profile (j_decompress_ptr cinfo,
101 : JOCTET **icc_data_ptr,
102 : unsigned int *icc_data_len)
103 : {
104 : jpeg_saved_marker_ptr marker;
105 5 : int num_markers = 0;
106 : int seq_no;
107 : JOCTET *icc_data;
108 : unsigned int total_length;
109 : #define MAX_SEQ_NO 255 /* sufficient since marker numbers are bytes */
110 : char marker_present[MAX_SEQ_NO+1]; /* 1 if marker found */
111 : unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
112 : unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */
113 :
114 5 : *icc_data_ptr = NULL; /* avoid confusion if FALSE return */
115 5 : *icc_data_len = 0;
116 :
117 : /* This first pass over the saved markers discovers whether there are
118 : * any ICC markers and verifies the consistency of the marker numbering.
119 : */
120 :
121 1280 : for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
122 1275 : marker_present[seq_no] = 0;
123 :
124 15 : for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
125 10 : if (marker_is_icc(marker)) {
126 0 : if (num_markers == 0)
127 0 : num_markers = GETJOCTET(marker->data[13]);
128 0 : else if (num_markers != GETJOCTET(marker->data[13]))
129 0 : return FALSE; /* inconsistent num_markers fields */
130 0 : seq_no = GETJOCTET(marker->data[12]);
131 0 : if (seq_no <= 0 || seq_no > num_markers)
132 0 : return FALSE; /* bogus sequence number */
133 0 : if (marker_present[seq_no])
134 0 : return FALSE; /* duplicate sequence numbers */
135 0 : marker_present[seq_no] = 1;
136 0 : data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
137 : }
138 : }
139 :
140 5 : if (num_markers == 0)
141 5 : return FALSE;
142 :
143 : /* Check for missing markers, count total space needed,
144 : * compute offset of each marker's part of the data.
145 : */
146 :
147 0 : total_length = 0;
148 0 : for (seq_no = 1; seq_no <= num_markers; seq_no++) {
149 0 : if (marker_present[seq_no] == 0)
150 0 : return FALSE; /* missing sequence number */
151 0 : data_offset[seq_no] = total_length;
152 0 : total_length += data_length[seq_no];
153 : }
154 :
155 0 : if (total_length <= 0)
156 0 : return FALSE; /* found only empty markers? */
157 :
158 : /* Allocate space for assembled data */
159 0 : icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
160 0 : if (icc_data == NULL)
161 0 : return FALSE; /* oops, out of memory */
162 :
163 : /* and fill it in */
164 0 : for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
165 0 : if (marker_is_icc(marker)) {
166 : JOCTET FAR *src_ptr;
167 : JOCTET *dst_ptr;
168 : unsigned int length;
169 0 : seq_no = GETJOCTET(marker->data[12]);
170 0 : dst_ptr = icc_data + data_offset[seq_no];
171 0 : src_ptr = marker->data + ICC_OVERHEAD_LEN;
172 0 : length = data_length[seq_no];
173 0 : while (length--) {
174 0 : *dst_ptr++ = *src_ptr++;
175 : }
176 : }
177 : }
178 :
179 0 : *icc_data_ptr = icc_data;
180 0 : *icc_data_len = total_length;
181 :
182 0 : return TRUE;
183 : }
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