+++ /dev/null
-/*
- * rdppm.c
- *
- * Copyright (C) 1991-1997, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains routines to read input images in PPM/PGM format.
- * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
- * The PBMPLUS library is NOT required to compile this software
- * (but it is highly useful as a set of PPM image manipulation programs).
- *
- * These routines may need modification for non-Unix environments or
- * specialized applications. As they stand, they assume input from
- * an ordinary stdio stream. They further assume that reading begins
- * at the start of the file; start_input may need work if the
- * user interface has already read some data (e.g., to determine that
- * the file is indeed PPM format).
- */
-
-#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
-
-#ifdef PPM_SUPPORTED
-
-
-/* Portions of this code are based on the PBMPLUS library, which is:
-**
-** Copyright (C) 1988 by Jef Poskanzer.
-**
-** Permission to use, copy, modify, and distribute this software and its
-** documentation for any purpose and without fee is hereby granted, provided
-** that the above copyright notice appear in all copies and that both that
-** copyright notice and this permission notice appear in supporting
-** documentation. This software is provided "as is" without express or
-** implied warranty.
-*/
-
-
-/* Macros to deal with unsigned chars as efficiently as compiler allows */
-
-#ifdef HAVE_UNSIGNED_CHAR
-typedef unsigned char U_CHAR;
-#define UCH(x) ((int) (x))
-#else /* !HAVE_UNSIGNED_CHAR */
-#ifdef CHAR_IS_UNSIGNED
-typedef char U_CHAR;
-#define UCH(x) ((int) (x))
-#else
-typedef char U_CHAR;
-#define UCH(x) ((int) (x) & 0xFF)
-#endif
-#endif /* HAVE_UNSIGNED_CHAR */
-
-
-#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
-
-
-/*
- * On most systems, reading individual bytes with getc() is drastically less
- * efficient than buffering a row at a time with fread(). On PCs, we must
- * allocate the buffer in near data space, because we are assuming small-data
- * memory model, wherein fread() can't reach far memory. If you need to
- * process very wide images on a PC, you might have to compile in large-memory
- * model, or else replace fread() with a getc() loop --- which will be much
- * slower.
- */
-
-
-/* Private version of data source object */
-
-typedef struct {
- struct cjpeg_source_struct pub; /* public fields */
-
- U_CHAR *iobuffer; /* non-FAR pointer to I/O buffer */
- JSAMPROW pixrow; /* FAR pointer to same */
- size_t buffer_width; /* width of I/O buffer */
- JSAMPLE *rescale; /* => maxval-remapping array, or NULL */
-} ppm_source_struct;
-
-typedef ppm_source_struct * ppm_source_ptr;
-
-
-LOCAL(int)
-pbm_getc (FILE * infile)
-/* Read next char, skipping over any comments */
-/* A comment/newline sequence is returned as a newline */
-{
- register int ch;
-
- ch = getc(infile);
- if (ch == '#') {
- do {
- ch = getc(infile);
- } while (ch != '\n' && ch != EOF);
- }
- return ch;
-}
-
-
-LOCAL(unsigned int)
-read_pbm_integer (j_compress_ptr cinfo, FILE * infile)
-/* Read an unsigned decimal integer from the PPM file */
-/* Swallows one trailing character after the integer */
-/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
-/* This should not be a problem in practice. */
-{
- register int ch;
- register unsigned int val;
-
- /* Skip any leading whitespace */
- do {
- ch = pbm_getc(infile);
- if (ch == EOF)
- ERREXIT(cinfo, JERR_INPUT_EOF);
- } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
-
- if (ch < '0' || ch > '9')
- ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
-
- val = ch - '0';
- while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
- val *= 10;
- val += ch - '0';
- }
- return val;
-}
-
-
-/*
- * Read one row of pixels.
- *
- * We provide several different versions depending on input file format.
- * In all cases, input is scaled to the size of JSAMPLE.
- *
- * A really fast path is provided for reading byte/sample raw files with
- * maxval = MAXJSAMPLE, which is the normal case for 8-bit data.
- */
-
-
-METHODDEF(JDIMENSION)
-get_text_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading text-format PGM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- FILE * infile = source->pub.input_file;
- register JSAMPROW ptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- ptr = source->pub.buffer[0];
- for (col = cinfo->image_width; col > 0; col--) {
- *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
- }
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_text_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading text-format PPM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- FILE * infile = source->pub.input_file;
- register JSAMPROW ptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- ptr = source->pub.buffer[0];
- for (col = cinfo->image_width; col > 0; col--) {
- *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
- *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
- *ptr++ = rescale[read_pbm_integer(cinfo, infile)];
- }
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_scaled_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading raw-byte-format PGM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- register JSAMPROW ptr;
- register U_CHAR * bufferptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
- ERREXIT(cinfo, JERR_INPUT_EOF);
- ptr = source->pub.buffer[0];
- bufferptr = source->iobuffer;
- for (col = cinfo->image_width; col > 0; col--) {
- *ptr++ = rescale[UCH(*bufferptr++)];
- }
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_scaled_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading raw-byte-format PPM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- register JSAMPROW ptr;
- register U_CHAR * bufferptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
- ERREXIT(cinfo, JERR_INPUT_EOF);
- ptr = source->pub.buffer[0];
- bufferptr = source->iobuffer;
- for (col = cinfo->image_width; col > 0; col--) {
- *ptr++ = rescale[UCH(*bufferptr++)];
- *ptr++ = rescale[UCH(*bufferptr++)];
- *ptr++ = rescale[UCH(*bufferptr++)];
- }
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_raw_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading raw-byte-format files with maxval = MAXJSAMPLE.
- * In this case we just read right into the JSAMPLE buffer!
- * Note that same code works for PPM and PGM files.
- */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
-
- if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
- ERREXIT(cinfo, JERR_INPUT_EOF);
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_word_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading raw-word-format PGM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- register JSAMPROW ptr;
- register U_CHAR * bufferptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
- ERREXIT(cinfo, JERR_INPUT_EOF);
- ptr = source->pub.buffer[0];
- bufferptr = source->iobuffer;
- for (col = cinfo->image_width; col > 0; col--) {
- register int temp;
- temp = UCH(*bufferptr++);
- temp |= UCH(*bufferptr++) << 8;
- *ptr++ = rescale[temp];
- }
- return 1;
-}
-
-
-METHODDEF(JDIMENSION)
-get_word_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-/* This version is for reading raw-word-format PPM files with any maxval */
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- register JSAMPROW ptr;
- register U_CHAR * bufferptr;
- register JSAMPLE *rescale = source->rescale;
- JDIMENSION col;
-
- if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
- ERREXIT(cinfo, JERR_INPUT_EOF);
- ptr = source->pub.buffer[0];
- bufferptr = source->iobuffer;
- for (col = cinfo->image_width; col > 0; col--) {
- register int temp;
- temp = UCH(*bufferptr++);
- temp |= UCH(*bufferptr++) << 8;
- *ptr++ = rescale[temp];
- temp = UCH(*bufferptr++);
- temp |= UCH(*bufferptr++) << 8;
- *ptr++ = rescale[temp];
- temp = UCH(*bufferptr++);
- temp |= UCH(*bufferptr++) << 8;
- *ptr++ = rescale[temp];
- }
- return 1;
-}
-
-
-/*
- * Read the file header; return image size and component count.
- */
-
-METHODDEF(void)
-start_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-{
- ppm_source_ptr source = (ppm_source_ptr) sinfo;
- int c;
- unsigned int w, h, maxval;
- boolean need_iobuffer, use_raw_buffer, need_rescale;
-
- if (getc(source->pub.input_file) != 'P')
- ERREXIT(cinfo, JERR_PPM_NOT);
-
- c = getc(source->pub.input_file); /* subformat discriminator character */
-
- /* detect unsupported variants (ie, PBM) before trying to read header */
- switch (c) {
- case '2': /* it's a text-format PGM file */
- case '3': /* it's a text-format PPM file */
- case '5': /* it's a raw-format PGM file */
- case '6': /* it's a raw-format PPM file */
- break;
- default:
- ERREXIT(cinfo, JERR_PPM_NOT);
- break;
- }
-
- /* fetch the remaining header info */
- w = read_pbm_integer(cinfo, source->pub.input_file);
- h = read_pbm_integer(cinfo, source->pub.input_file);
- maxval = read_pbm_integer(cinfo, source->pub.input_file);
-
- if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
- ERREXIT(cinfo, JERR_PPM_NOT);
-
- cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
- cinfo->image_width = (JDIMENSION) w;
- cinfo->image_height = (JDIMENSION) h;
-
- /* initialize flags to most common settings */
- need_iobuffer = TRUE; /* do we need an I/O buffer? */
- use_raw_buffer = FALSE; /* do we map input buffer onto I/O buffer? */
- need_rescale = TRUE; /* do we need a rescale array? */
-
- switch (c) {
- case '2': /* it's a text-format PGM file */
- cinfo->input_components = 1;
- cinfo->in_color_space = JCS_GRAYSCALE;
- TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);
- source->pub.get_pixel_rows = get_text_gray_row;
- need_iobuffer = FALSE;
- break;
-
- case '3': /* it's a text-format PPM file */
- cinfo->input_components = 3;
- cinfo->in_color_space = JCS_RGB;
- TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);
- source->pub.get_pixel_rows = get_text_rgb_row;
- need_iobuffer = FALSE;
- break;
-
- case '5': /* it's a raw-format PGM file */
- cinfo->input_components = 1;
- cinfo->in_color_space = JCS_GRAYSCALE;
- TRACEMS2(cinfo, 1, JTRC_PGM, w, h);
- if (maxval > 255) {
- source->pub.get_pixel_rows = get_word_gray_row;
- } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
- source->pub.get_pixel_rows = get_raw_row;
- use_raw_buffer = TRUE;
- need_rescale = FALSE;
- } else {
- source->pub.get_pixel_rows = get_scaled_gray_row;
- }
- break;
-
- case '6': /* it's a raw-format PPM file */
- cinfo->input_components = 3;
- cinfo->in_color_space = JCS_RGB;
- TRACEMS2(cinfo, 1, JTRC_PPM, w, h);
- if (maxval > 255) {
- source->pub.get_pixel_rows = get_word_rgb_row;
- } else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
- source->pub.get_pixel_rows = get_raw_row;
- use_raw_buffer = TRUE;
- need_rescale = FALSE;
- } else {
- source->pub.get_pixel_rows = get_scaled_rgb_row;
- }
- break;
- }
-
- /* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
- if (need_iobuffer) {
- source->buffer_width = (size_t) w * cinfo->input_components *
- ((maxval<=255) ? SIZEOF(U_CHAR) : (2*SIZEOF(U_CHAR)));
- source->iobuffer = (U_CHAR *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- source->buffer_width);
- }
-
- /* Create compressor input buffer. */
- if (use_raw_buffer) {
- /* For unscaled raw-input case, we can just map it onto the I/O buffer. */
- /* Synthesize a JSAMPARRAY pointer structure */
- /* Cast here implies near->far pointer conversion on PCs */
- source->pixrow = (JSAMPROW) source->iobuffer;
- source->pub.buffer = & source->pixrow;
- source->pub.buffer_height = 1;
- } else {
- /* Need to translate anyway, so make a separate sample buffer. */
- source->pub.buffer = (*cinfo->mem->alloc_sarray)
- ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (JDIMENSION) w * cinfo->input_components, (JDIMENSION) 1);
- source->pub.buffer_height = 1;
- }
-
- /* Compute the rescaling array if required. */
- if (need_rescale) {
- INT32 val, half_maxval;
-
- /* On 16-bit-int machines we have to be careful of maxval = 65535 */
- source->rescale = (JSAMPLE *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (size_t) (((long) maxval + 1L) * SIZEOF(JSAMPLE)));
- half_maxval = maxval / 2;
- for (val = 0; val <= (INT32) maxval; val++) {
- /* The multiplication here must be done in 32 bits to avoid overflow */
- source->rescale[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval);
- }
- }
-}
-
-
-/*
- * Finish up at the end of the file.
- */
-
-METHODDEF(void)
-finish_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
-{
- /* no work */
-}
-
-
-/*
- * The module selection routine for PPM format input.
- */
-
-GLOBAL(cjpeg_source_ptr)
-jinit_read_ppm (j_compress_ptr cinfo)
-{
- ppm_source_ptr source;
-
- /* Create module interface object */
- source = (ppm_source_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(ppm_source_struct));
- /* Fill in method ptrs, except get_pixel_rows which start_input sets */
- source->pub.start_input = start_input_ppm;
- source->pub.finish_input = finish_input_ppm;
-
- return (cjpeg_source_ptr) source;
-}
-
-#endif /* PPM_SUPPORTED */
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