55d342c788
TJPARAM_MAXPIXELS was previously hidden and used only for fuzz testing, but it is potentially useful for calling applications as well, particularly if they want to guard against excessive memory consumption by the tj3LoadImage*() functions. The parameter has also been extended to decompression and lossless transformation functions/methods, mainly as a convenience. (It was already possible for calling applications to impose their own JPEG image size limits by reading the JPEG header prior to decompressing or transforming the image.)
721 lines
24 KiB
C
721 lines
24 KiB
C
/*
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* rdgif.c
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*
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* This file was part of the Independent JPEG Group's software:
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* Modified 2019 by Guido Vollbeding.
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* libjpeg-turbo Modifications:
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* Copyright (C) 2021-2023, D. R. Commander.
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* For conditions of distribution and use, see the accompanying README.ijg
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* file.
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*
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* This file contains routines to read input images in GIF format.
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*
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* These routines may need modification for non-Unix environments or
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* specialized applications. As they stand, they assume input from
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* an ordinary stdio stream. They further assume that reading begins
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* at the start of the file; start_input may need work if the
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* user interface has already read some data (e.g., to determine that
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* the file is indeed GIF format).
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*/
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/*
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* This code is loosely based on giftoppm from the PBMPLUS distribution
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* of Feb. 1991. That file contains the following copyright notice:
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* +-------------------------------------------------------------------+
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* | Copyright 1990, David Koblas. |
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* | Permission to use, copy, modify, and distribute this software |
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* | and its documentation for any purpose and without fee is hereby |
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* | granted, provided that the above copyright notice appear in all |
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* | copies and that both that copyright notice and this permission |
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* | notice appear in supporting documentation. This software is |
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* | provided "as is" without express or implied warranty. |
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* +-------------------------------------------------------------------+
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*/
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#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
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#include "jsamplecomp.h"
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#if defined(GIF_SUPPORTED) && \
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(BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED))
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/* Macros to deal with unsigned chars as efficiently as compiler allows */
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typedef unsigned char U_CHAR;
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#define UCH(x) ((int)(x))
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#define ReadOK(file, buffer, len) \
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(fread(buffer, 1, len, file) == ((size_t)(len)))
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#define MAXCOLORMAPSIZE 256 /* max # of colors in a GIF colormap */
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#define NUMCOLORS 3 /* # of colors */
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#define CM_RED 0 /* color component numbers */
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#define CM_GREEN 1
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#define CM_BLUE 2
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#define MAX_LZW_BITS 12 /* maximum LZW code size */
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#define LZW_TABLE_SIZE (1 << MAX_LZW_BITS) /* # of possible LZW symbols */
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/* Macros for extracting header data --- note we assume chars may be signed */
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#define LM_to_uint(array, offset) \
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((unsigned int)UCH(array[offset]) + \
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(((unsigned int)UCH(array[offset + 1])) << 8))
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#define BitSet(byte, bit) ((byte) & (bit))
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#define INTERLACE 0x40 /* mask for bit signifying interlaced image */
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#define COLORMAPFLAG 0x80 /* mask for bit signifying colormap presence */
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/*
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* LZW decompression tables look like this:
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* symbol_head[K] = prefix symbol of any LZW symbol K (0..LZW_TABLE_SIZE-1)
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* symbol_tail[K] = suffix byte of any LZW symbol K (0..LZW_TABLE_SIZE-1)
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* Note that entries 0..end_code of the above tables are not used,
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* since those symbols represent raw bytes or special codes.
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*
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* The stack represents the not-yet-used expansion of the last LZW symbol.
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* In the worst case, a symbol could expand to as many bytes as there are
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* LZW symbols, so we allocate LZW_TABLE_SIZE bytes for the stack.
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* (This is conservative since that number includes the raw-byte symbols.)
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*/
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/* Private version of data source object */
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typedef struct {
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struct cjpeg_source_struct pub; /* public fields */
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j_compress_ptr cinfo; /* back link saves passing separate parm */
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_JSAMPARRAY colormap; /* GIF colormap (converted to my format) */
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/* State for GetCode and LZWReadByte */
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U_CHAR code_buf[256 + 4]; /* current input data block */
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int last_byte; /* # of bytes in code_buf */
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int last_bit; /* # of bits in code_buf */
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int cur_bit; /* next bit index to read */
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boolean first_time; /* flags first call to GetCode */
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boolean out_of_blocks; /* TRUE if hit terminator data block */
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int input_code_size; /* codesize given in GIF file */
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int clear_code, end_code; /* values for Clear and End codes */
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int code_size; /* current actual code size */
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int limit_code; /* 2^code_size */
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int max_code; /* first unused code value */
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/* Private state for LZWReadByte */
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int oldcode; /* previous LZW symbol */
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int firstcode; /* first byte of oldcode's expansion */
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/* LZW symbol table and expansion stack */
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UINT16 *symbol_head; /* => table of prefix symbols */
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UINT8 *symbol_tail; /* => table of suffix bytes */
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UINT8 *symbol_stack; /* => stack for symbol expansions */
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UINT8 *sp; /* stack pointer */
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/* State for interlaced image processing */
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boolean is_interlaced; /* TRUE if have interlaced image */
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jvirt_sarray_ptr interlaced_image; /* full image in interlaced order */
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JDIMENSION cur_row_number; /* need to know actual row number */
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JDIMENSION pass2_offset; /* # of pixel rows in pass 1 */
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JDIMENSION pass3_offset; /* # of pixel rows in passes 1&2 */
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JDIMENSION pass4_offset; /* # of pixel rows in passes 1,2,3 */
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} gif_source_struct;
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typedef gif_source_struct *gif_source_ptr;
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/* Forward declarations */
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METHODDEF(JDIMENSION) get_pixel_rows(j_compress_ptr cinfo,
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cjpeg_source_ptr sinfo);
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METHODDEF(JDIMENSION) load_interlaced_image(j_compress_ptr cinfo,
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cjpeg_source_ptr sinfo);
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METHODDEF(JDIMENSION) get_interlaced_row(j_compress_ptr cinfo,
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cjpeg_source_ptr sinfo);
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LOCAL(int)
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ReadByte(gif_source_ptr sinfo)
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/* Read next byte from GIF file */
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{
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register FILE *infile = sinfo->pub.input_file;
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register int c;
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if ((c = getc(infile)) == EOF)
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ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
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return c;
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}
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LOCAL(int)
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GetDataBlock(gif_source_ptr sinfo, U_CHAR *buf)
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/* Read a GIF data block, which has a leading count byte */
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/* A zero-length block marks the end of a data block sequence */
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{
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int count;
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count = ReadByte(sinfo);
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if (count > 0) {
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if (!ReadOK(sinfo->pub.input_file, buf, count))
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ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
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}
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return count;
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}
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LOCAL(void)
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SkipDataBlocks(gif_source_ptr sinfo)
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/* Skip a series of data blocks, until a block terminator is found */
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{
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U_CHAR buf[256];
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while (GetDataBlock(sinfo, buf) > 0)
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/* skip */;
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}
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LOCAL(void)
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ReInitLZW(gif_source_ptr sinfo)
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/* (Re)initialize LZW state; shared code for startup and Clear processing */
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{
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sinfo->code_size = sinfo->input_code_size + 1;
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sinfo->limit_code = sinfo->clear_code << 1; /* 2^code_size */
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sinfo->max_code = sinfo->clear_code + 2; /* first unused code value */
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sinfo->sp = sinfo->symbol_stack; /* init stack to empty */
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}
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LOCAL(void)
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InitLZWCode(gif_source_ptr sinfo)
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/* Initialize for a series of LZWReadByte (and hence GetCode) calls */
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{
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/* GetCode initialization */
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sinfo->last_byte = 2; /* make safe to "recopy last two bytes" */
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sinfo->code_buf[0] = 0;
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sinfo->code_buf[1] = 0;
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sinfo->last_bit = 0; /* nothing in the buffer */
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sinfo->cur_bit = 0; /* force buffer load on first call */
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sinfo->first_time = TRUE;
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sinfo->out_of_blocks = FALSE;
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/* LZWReadByte initialization: */
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/* compute special code values (note that these do not change later) */
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sinfo->clear_code = 1 << sinfo->input_code_size;
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sinfo->end_code = sinfo->clear_code + 1;
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ReInitLZW(sinfo);
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}
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LOCAL(int)
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GetCode(gif_source_ptr sinfo)
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/* Fetch the next code_size bits from the GIF data */
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/* We assume code_size is less than 16 */
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{
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register int accum;
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int offs, count;
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while (sinfo->cur_bit + sinfo->code_size > sinfo->last_bit) {
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/* Time to reload the buffer */
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/* First time, share code with Clear case */
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if (sinfo->first_time) {
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sinfo->first_time = FALSE;
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return sinfo->clear_code;
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}
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if (sinfo->out_of_blocks) {
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WARNMS(sinfo->cinfo, JWRN_GIF_NOMOREDATA);
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return sinfo->end_code; /* fake something useful */
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}
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/* preserve last two bytes of what we have -- assume code_size <= 16 */
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sinfo->code_buf[0] = sinfo->code_buf[sinfo->last_byte-2];
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sinfo->code_buf[1] = sinfo->code_buf[sinfo->last_byte-1];
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/* Load more bytes; set flag if we reach the terminator block */
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if ((count = GetDataBlock(sinfo, &sinfo->code_buf[2])) == 0) {
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sinfo->out_of_blocks = TRUE;
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WARNMS(sinfo->cinfo, JWRN_GIF_NOMOREDATA);
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return sinfo->end_code; /* fake something useful */
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}
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/* Reset counters */
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sinfo->cur_bit = (sinfo->cur_bit - sinfo->last_bit) + 16;
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sinfo->last_byte = 2 + count;
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sinfo->last_bit = sinfo->last_byte * 8;
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}
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/* Form up next 24 bits in accum */
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offs = sinfo->cur_bit >> 3; /* byte containing cur_bit */
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accum = UCH(sinfo->code_buf[offs + 2]);
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accum <<= 8;
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accum |= UCH(sinfo->code_buf[offs + 1]);
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accum <<= 8;
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accum |= UCH(sinfo->code_buf[offs]);
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/* Right-align cur_bit in accum, then mask off desired number of bits */
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accum >>= (sinfo->cur_bit & 7);
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sinfo->cur_bit += sinfo->code_size;
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return accum & ((1 << sinfo->code_size) - 1);
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}
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LOCAL(int)
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LZWReadByte(gif_source_ptr sinfo)
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/* Read an LZW-compressed byte */
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{
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register int code; /* current working code */
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int incode; /* saves actual input code */
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/* If any codes are stacked from a previously read symbol, return them */
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if (sinfo->sp > sinfo->symbol_stack)
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return (int)(*(--sinfo->sp));
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/* Time to read a new symbol */
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code = GetCode(sinfo);
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if (code == sinfo->clear_code) {
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/* Reinit state, swallow any extra Clear codes, and */
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/* return next code, which is expected to be a raw byte. */
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ReInitLZW(sinfo);
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do {
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code = GetCode(sinfo);
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} while (code == sinfo->clear_code);
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if (code > sinfo->clear_code) { /* make sure it is a raw byte */
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WARNMS(sinfo->cinfo, JWRN_GIF_BADDATA);
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code = 0; /* use something valid */
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}
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/* make firstcode, oldcode valid! */
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sinfo->firstcode = sinfo->oldcode = code;
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return code;
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}
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if (code == sinfo->end_code) {
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/* Skip the rest of the image, unless GetCode already read terminator */
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if (!sinfo->out_of_blocks) {
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SkipDataBlocks(sinfo);
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sinfo->out_of_blocks = TRUE;
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}
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/* Complain that there's not enough data */
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WARNMS(sinfo->cinfo, JWRN_GIF_ENDCODE);
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/* Pad data with 0's */
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return 0; /* fake something usable */
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}
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/* Got normal raw byte or LZW symbol */
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incode = code; /* save for a moment */
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if (code >= sinfo->max_code) { /* special case for not-yet-defined symbol */
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/* code == max_code is OK; anything bigger is bad data */
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if (code > sinfo->max_code) {
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WARNMS(sinfo->cinfo, JWRN_GIF_BADDATA);
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incode = 0; /* prevent creation of loops in symbol table */
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}
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/* this symbol will be defined as oldcode/firstcode */
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*(sinfo->sp++) = (UINT8)sinfo->firstcode;
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code = sinfo->oldcode;
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}
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/* If it's a symbol, expand it into the stack */
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while (code >= sinfo->clear_code) {
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*(sinfo->sp++) = sinfo->symbol_tail[code]; /* tail is a byte value */
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code = sinfo->symbol_head[code]; /* head is another LZW symbol */
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}
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/* At this point code just represents a raw byte */
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sinfo->firstcode = code; /* save for possible future use */
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/* If there's room in table... */
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if ((code = sinfo->max_code) < LZW_TABLE_SIZE) {
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/* Define a new symbol = prev sym + head of this sym's expansion */
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sinfo->symbol_head[code] = (UINT16)sinfo->oldcode;
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sinfo->symbol_tail[code] = (UINT8)sinfo->firstcode;
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sinfo->max_code++;
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/* Is it time to increase code_size? */
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if (sinfo->max_code >= sinfo->limit_code &&
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sinfo->code_size < MAX_LZW_BITS) {
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sinfo->code_size++;
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sinfo->limit_code <<= 1; /* keep equal to 2^code_size */
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}
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}
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sinfo->oldcode = incode; /* save last input symbol for future use */
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return sinfo->firstcode; /* return first byte of symbol's expansion */
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}
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LOCAL(void)
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ReadColorMap(gif_source_ptr sinfo, int cmaplen, _JSAMPARRAY cmap)
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/* Read a GIF colormap */
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{
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int i, gray = 1;
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for (i = 0; i < cmaplen; i++) {
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#if BITS_IN_JSAMPLE == 8
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#define UPSCALE(x) (x)
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#else
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#define UPSCALE(x) ((x) << (BITS_IN_JSAMPLE - 8))
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#endif
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cmap[CM_RED][i] = (_JSAMPLE)UPSCALE(ReadByte(sinfo));
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cmap[CM_GREEN][i] = (_JSAMPLE)UPSCALE(ReadByte(sinfo));
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cmap[CM_BLUE][i] = (_JSAMPLE)UPSCALE(ReadByte(sinfo));
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if (cmap[CM_RED][i] != cmap[CM_GREEN][i] ||
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cmap[CM_GREEN][i] != cmap[CM_BLUE][i])
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gray = 0;
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}
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if (sinfo->cinfo->in_color_space == JCS_RGB && gray) {
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sinfo->cinfo->in_color_space = JCS_GRAYSCALE;
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sinfo->cinfo->input_components = 1;
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}
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}
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LOCAL(void)
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DoExtension(gif_source_ptr sinfo)
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/* Process an extension block */
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/* Currently we ignore 'em all */
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{
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int extlabel;
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/* Read extension label byte */
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extlabel = ReadByte(sinfo);
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TRACEMS1(sinfo->cinfo, 1, JTRC_GIF_EXTENSION, extlabel);
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/* Skip the data block(s) associated with the extension */
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SkipDataBlocks(sinfo);
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}
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/*
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* Read the file header; return image size and component count.
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*/
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METHODDEF(void)
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start_input_gif(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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gif_source_ptr source = (gif_source_ptr)sinfo;
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U_CHAR hdrbuf[10]; /* workspace for reading control blocks */
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unsigned int width, height; /* image dimensions */
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int colormaplen, aspectRatio;
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int c;
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/* Read and verify GIF Header */
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if (!ReadOK(source->pub.input_file, hdrbuf, 6))
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ERREXIT(cinfo, JERR_GIF_NOT);
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if (hdrbuf[0] != 'G' || hdrbuf[1] != 'I' || hdrbuf[2] != 'F')
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ERREXIT(cinfo, JERR_GIF_NOT);
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/* Check for expected version numbers.
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* If unknown version, give warning and try to process anyway;
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* this is per recommendation in GIF89a standard.
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*/
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if ((hdrbuf[3] != '8' || hdrbuf[4] != '7' || hdrbuf[5] != 'a') &&
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(hdrbuf[3] != '8' || hdrbuf[4] != '9' || hdrbuf[5] != 'a'))
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TRACEMS3(cinfo, 1, JTRC_GIF_BADVERSION, hdrbuf[3], hdrbuf[4], hdrbuf[5]);
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/* Read and decipher Logical Screen Descriptor */
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if (!ReadOK(source->pub.input_file, hdrbuf, 7))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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width = LM_to_uint(hdrbuf, 0);
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height = LM_to_uint(hdrbuf, 2);
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if (width == 0 || height == 0)
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ERREXIT(cinfo, JERR_GIF_EMPTY);
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if (sinfo->max_pixels &&
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(unsigned long long)width * height > sinfo->max_pixels)
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ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, sinfo->max_pixels);
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/* we ignore the color resolution, sort flag, and background color index */
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aspectRatio = UCH(hdrbuf[6]);
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if (aspectRatio != 0 && aspectRatio != 49)
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TRACEMS(cinfo, 1, JTRC_GIF_NONSQUARE);
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/* Allocate space to store the colormap */
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source->colormap = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray)
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((j_common_ptr)cinfo, JPOOL_IMAGE, (JDIMENSION)MAXCOLORMAPSIZE,
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(JDIMENSION)NUMCOLORS);
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colormaplen = 0; /* indicate initialization */
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/* Read global colormap if header indicates it is present */
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if (BitSet(hdrbuf[4], COLORMAPFLAG)) {
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colormaplen = 2 << (hdrbuf[4] & 0x07);
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ReadColorMap(source, colormaplen, source->colormap);
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}
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/* Scan until we reach start of desired image.
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* We don't currently support skipping images, but could add it easily.
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*/
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for (;;) {
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c = ReadByte(source);
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if (c == ';') /* GIF terminator?? */
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ERREXIT(cinfo, JERR_GIF_IMAGENOTFOUND);
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if (c == '!') { /* Extension */
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DoExtension(source);
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continue;
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}
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if (c != ',') { /* Not an image separator? */
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WARNMS1(cinfo, JWRN_GIF_CHAR, c);
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continue;
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}
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|
|
/* Read and decipher Local Image Descriptor */
|
|
if (!ReadOK(source->pub.input_file, hdrbuf, 9))
|
|
ERREXIT(cinfo, JERR_INPUT_EOF);
|
|
/* we ignore top/left position info, also sort flag */
|
|
width = LM_to_uint(hdrbuf, 4);
|
|
height = LM_to_uint(hdrbuf, 6);
|
|
if (width == 0 || height == 0)
|
|
ERREXIT(cinfo, JERR_GIF_EMPTY);
|
|
if (sinfo->max_pixels &&
|
|
(unsigned long long)width * height > sinfo->max_pixels)
|
|
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, sinfo->max_pixels);
|
|
source->is_interlaced = (BitSet(hdrbuf[8], INTERLACE) != 0);
|
|
|
|
/* Read local colormap if header indicates it is present */
|
|
/* Note: if we wanted to support skipping images, */
|
|
/* we'd need to skip rather than read colormap for ignored images */
|
|
if (BitSet(hdrbuf[8], COLORMAPFLAG)) {
|
|
colormaplen = 2 << (hdrbuf[8] & 0x07);
|
|
ReadColorMap(source, colormaplen, source->colormap);
|
|
}
|
|
|
|
source->input_code_size = ReadByte(source); /* get min-code-size byte */
|
|
if (source->input_code_size < 2 || source->input_code_size > 8)
|
|
ERREXIT1(cinfo, JERR_GIF_CODESIZE, source->input_code_size);
|
|
|
|
/* Reached desired image, so break out of loop */
|
|
/* If we wanted to skip this image, */
|
|
/* we'd call SkipDataBlocks and then continue the loop */
|
|
break;
|
|
}
|
|
|
|
/* Prepare to read selected image: first initialize LZW decompressor */
|
|
source->symbol_head = (UINT16 *)
|
|
(*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE,
|
|
LZW_TABLE_SIZE * sizeof(UINT16));
|
|
source->symbol_tail = (UINT8 *)
|
|
(*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE,
|
|
LZW_TABLE_SIZE * sizeof(UINT8));
|
|
source->symbol_stack = (UINT8 *)
|
|
(*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE,
|
|
LZW_TABLE_SIZE * sizeof(UINT8));
|
|
InitLZWCode(source);
|
|
|
|
/*
|
|
* If image is interlaced, we read it into a full-size sample array,
|
|
* decompressing as we go; then get_interlaced_row selects rows from the
|
|
* sample array in the proper order.
|
|
*/
|
|
if (source->is_interlaced) {
|
|
/* We request the virtual array now, but can't access it until virtual
|
|
* arrays have been allocated. Hence, the actual work of reading the
|
|
* image is postponed until the first call to get_pixel_rows.
|
|
*/
|
|
source->interlaced_image = (*cinfo->mem->request_virt_sarray)
|
|
((j_common_ptr)cinfo, JPOOL_IMAGE, FALSE,
|
|
(JDIMENSION)width, (JDIMENSION)height, (JDIMENSION)1);
|
|
if (cinfo->progress != NULL) {
|
|
cd_progress_ptr progress = (cd_progress_ptr)cinfo->progress;
|
|
progress->total_extra_passes++; /* count file input as separate pass */
|
|
}
|
|
source->pub.get_pixel_rows = load_interlaced_image;
|
|
} else {
|
|
source->pub.get_pixel_rows = get_pixel_rows;
|
|
}
|
|
|
|
if (cinfo->in_color_space != JCS_GRAYSCALE) {
|
|
cinfo->in_color_space = JCS_RGB;
|
|
cinfo->input_components = NUMCOLORS;
|
|
}
|
|
|
|
/* Create compressor input buffer. */
|
|
source->pub._buffer = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray)
|
|
((j_common_ptr)cinfo, JPOOL_IMAGE,
|
|
(JDIMENSION)width * cinfo->input_components, (JDIMENSION)1);
|
|
source->pub.buffer_height = 1;
|
|
|
|
/* Pad colormap for safety. */
|
|
for (c = colormaplen; c < source->clear_code; c++) {
|
|
source->colormap[CM_RED][c] =
|
|
source->colormap[CM_GREEN][c] =
|
|
source->colormap[CM_BLUE][c] = _CENTERJSAMPLE;
|
|
}
|
|
|
|
/* Return info about the image. */
|
|
cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
|
|
cinfo->image_width = width;
|
|
cinfo->image_height = height;
|
|
|
|
TRACEMS3(cinfo, 1, JTRC_GIF, width, height, colormaplen);
|
|
}
|
|
|
|
|
|
/*
|
|
* Read one row of pixels.
|
|
* This version is used for noninterlaced GIF images:
|
|
* we read directly from the GIF file.
|
|
*/
|
|
|
|
METHODDEF(JDIMENSION)
|
|
get_pixel_rows(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
|
|
{
|
|
gif_source_ptr source = (gif_source_ptr)sinfo;
|
|
register int c;
|
|
register _JSAMPROW ptr;
|
|
register JDIMENSION col;
|
|
register _JSAMPARRAY colormap = source->colormap;
|
|
|
|
ptr = source->pub._buffer[0];
|
|
if (cinfo->in_color_space == JCS_GRAYSCALE) {
|
|
for (col = cinfo->image_width; col > 0; col--) {
|
|
c = LZWReadByte(source);
|
|
*ptr++ = colormap[CM_RED][c];
|
|
}
|
|
} else {
|
|
for (col = cinfo->image_width; col > 0; col--) {
|
|
c = LZWReadByte(source);
|
|
*ptr++ = colormap[CM_RED][c];
|
|
*ptr++ = colormap[CM_GREEN][c];
|
|
*ptr++ = colormap[CM_BLUE][c];
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* Read one row of pixels.
|
|
* This version is used for the first call on get_pixel_rows when
|
|
* reading an interlaced GIF file: we read the whole image into memory.
|
|
*/
|
|
|
|
METHODDEF(JDIMENSION)
|
|
load_interlaced_image(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
|
|
{
|
|
gif_source_ptr source = (gif_source_ptr)sinfo;
|
|
register _JSAMPROW sptr;
|
|
register JDIMENSION col;
|
|
JDIMENSION row;
|
|
cd_progress_ptr progress = (cd_progress_ptr)cinfo->progress;
|
|
|
|
/* Read the interlaced image into the virtual array we've created. */
|
|
for (row = 0; row < cinfo->image_height; row++) {
|
|
if (progress != NULL) {
|
|
progress->pub.pass_counter = (long)row;
|
|
progress->pub.pass_limit = (long)cinfo->image_height;
|
|
(*progress->pub.progress_monitor) ((j_common_ptr)cinfo);
|
|
}
|
|
sptr = *(_JSAMPARRAY)(*cinfo->mem->access_virt_sarray)
|
|
((j_common_ptr)cinfo, source->interlaced_image, row, (JDIMENSION)1,
|
|
TRUE);
|
|
for (col = cinfo->image_width; col > 0; col--) {
|
|
*sptr++ = (_JSAMPLE)LZWReadByte(source);
|
|
}
|
|
}
|
|
if (progress != NULL)
|
|
progress->completed_extra_passes++;
|
|
|
|
/* Replace method pointer so subsequent calls don't come here. */
|
|
source->pub.get_pixel_rows = get_interlaced_row;
|
|
/* Initialize for get_interlaced_row, and perform first call on it. */
|
|
source->cur_row_number = 0;
|
|
source->pass2_offset = (cinfo->image_height + 7) / 8;
|
|
source->pass3_offset = source->pass2_offset + (cinfo->image_height + 3) / 8;
|
|
source->pass4_offset = source->pass3_offset + (cinfo->image_height + 1) / 4;
|
|
|
|
return get_interlaced_row(cinfo, sinfo);
|
|
}
|
|
|
|
|
|
/*
|
|
* Read one row of pixels.
|
|
* This version is used for interlaced GIF images:
|
|
* we read from the virtual array.
|
|
*/
|
|
|
|
METHODDEF(JDIMENSION)
|
|
get_interlaced_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
|
|
{
|
|
gif_source_ptr source = (gif_source_ptr)sinfo;
|
|
register int c;
|
|
register _JSAMPROW sptr, ptr;
|
|
register JDIMENSION col;
|
|
register _JSAMPARRAY colormap = source->colormap;
|
|
JDIMENSION irow;
|
|
|
|
/* Figure out which row of interlaced image is needed, and access it. */
|
|
switch ((int)(source->cur_row_number & 7)) {
|
|
case 0: /* first-pass row */
|
|
irow = source->cur_row_number >> 3;
|
|
break;
|
|
case 4: /* second-pass row */
|
|
irow = (source->cur_row_number >> 3) + source->pass2_offset;
|
|
break;
|
|
case 2: /* third-pass row */
|
|
case 6:
|
|
irow = (source->cur_row_number >> 2) + source->pass3_offset;
|
|
break;
|
|
default: /* fourth-pass row */
|
|
irow = (source->cur_row_number >> 1) + source->pass4_offset;
|
|
}
|
|
sptr = *(_JSAMPARRAY)(*cinfo->mem->access_virt_sarray)
|
|
((j_common_ptr)cinfo, source->interlaced_image, irow, (JDIMENSION)1,
|
|
FALSE);
|
|
/* Scan the row, expand colormap, and output */
|
|
ptr = source->pub._buffer[0];
|
|
if (cinfo->in_color_space == JCS_GRAYSCALE) {
|
|
for (col = cinfo->image_width; col > 0; col--) {
|
|
c = *sptr++;
|
|
*ptr++ = colormap[CM_RED][c];
|
|
}
|
|
} else {
|
|
for (col = cinfo->image_width; col > 0; col--) {
|
|
c = *sptr++;
|
|
*ptr++ = colormap[CM_RED][c];
|
|
*ptr++ = colormap[CM_GREEN][c];
|
|
*ptr++ = colormap[CM_BLUE][c];
|
|
}
|
|
}
|
|
source->cur_row_number++; /* for next time */
|
|
return 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* Finish up at the end of the file.
|
|
*/
|
|
|
|
METHODDEF(void)
|
|
finish_input_gif(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
|
|
{
|
|
/* no work */
|
|
}
|
|
|
|
|
|
/*
|
|
* The module selection routine for GIF format input.
|
|
*/
|
|
|
|
GLOBAL(cjpeg_source_ptr)
|
|
_jinit_read_gif(j_compress_ptr cinfo)
|
|
{
|
|
gif_source_ptr source;
|
|
|
|
if (cinfo->data_precision != BITS_IN_JSAMPLE)
|
|
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
|
|
|
|
/* Create module interface object */
|
|
source = (gif_source_ptr)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
|
|
sizeof(gif_source_struct));
|
|
source->cinfo = cinfo; /* make back link for subroutines */
|
|
/* Fill in method ptrs, except get_pixel_rows which start_input sets */
|
|
source->pub.start_input = start_input_gif;
|
|
source->pub.finish_input = finish_input_gif;
|
|
source->pub.max_pixels = 0;
|
|
|
|
return (cjpeg_source_ptr)source;
|
|
}
|
|
|
|
#endif /* defined(GIF_SUPPORTED) &&
|
|
(BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED)) */
|