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Diffstat (limited to 'image/decoders/iccjpeg.c')
| -rw-r--r-- | image/decoders/iccjpeg.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/image/decoders/iccjpeg.c b/image/decoders/iccjpeg.c new file mode 100644 index 000000000..af014cf6b --- /dev/null +++ b/image/decoders/iccjpeg.c @@ -0,0 +1,195 @@ +/* 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/. */ + +/* + * iccjpeg.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; +} |