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* Copyright (C) 1991-1997, Thomas G. Lane.
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* Modified 2009 by Bill Allombert, Guido Vollbeding.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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* This file contains routines to read input images in PPM/PGM format.
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* The extended 2-byte-per-sample raw PPM/PGM formats are supported.
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* The PBMPLUS library is NOT required to compile this software
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* (but it is highly useful as a set of PPM image manipulation programs).
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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 PPM format).
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#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
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/* Portions of this code are based on the PBMPLUS library, which is:
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** Copyright (C) 1988 by Jef Poskanzer.
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** Permission to use, copy, modify, and distribute this software and its
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** documentation for any purpose and without fee is hereby granted, provided
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** that the above copyright notice appear in all copies and that both that
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** copyright notice and this permission notice appear in supporting
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** documentation. This software is provided "as is" without express or
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/* Macros to deal with unsigned chars as efficiently as compiler allows */
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#ifdef HAVE_UNSIGNED_CHAR
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typedef unsigned char U_CHAR;
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#define UCH(x) ((int) (x))
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#else /* !HAVE_UNSIGNED_CHAR */
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#ifdef CHAR_IS_UNSIGNED
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#define UCH(x) ((int) (x))
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#define UCH(x) ((int) (x) & 0xFF)
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#endif /* HAVE_UNSIGNED_CHAR */
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#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
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* On most systems, reading individual bytes with getc() is drastically less
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* efficient than buffering a row at a time with fread(). On PCs, we must
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* allocate the buffer in near data space, because we are assuming small-data
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* memory model, wherein fread() can't reach far memory. If you need to
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* process very wide images on a PC, you might have to compile in large-memory
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* model, or else replace fread() with a getc() loop --- which will be much
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/* Private version of data source object */
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struct cjpeg_source_struct pub; /* public fields */
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U_CHAR *iobuffer; /* non-FAR pointer to I/O buffer */
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JSAMPROW pixrow; /* FAR pointer to same */
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size_t buffer_width; /* width of I/O buffer */
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JSAMPLE *rescale; /* => maxval-remapping array, or NULL */
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typedef ppm_source_struct * ppm_source_ptr;
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pbm_getc (FILE * infile)
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/* Read next char, skipping over any comments */
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/* A comment/newline sequence is returned as a newline */
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} while (ch != '\n' && ch != EOF);
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read_pbm_integer (j_compress_ptr cinfo, FILE * infile)
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/* Read an unsigned decimal integer from the PPM file */
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/* Swallows one trailing character after the integer */
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/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
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/* This should not be a problem in practice. */
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register unsigned int val;
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/* Skip any leading whitespace */
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ch = pbm_getc(infile);
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ERREXIT(cinfo, JERR_INPUT_EOF);
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} while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
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if (ch < '0' || ch > '9')
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ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
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while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
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* Read one row of pixels.
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* We provide several different versions depending on input file format.
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* In all cases, input is scaled to the size of JSAMPLE.
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* A really fast path is provided for reading byte/sample raw files with
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* maxval = MAXJSAMPLE, which is the normal case for 8-bit data.
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METHODDEF(JDIMENSION)
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get_text_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading text-format PGM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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FILE * infile = source->pub.input_file;
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register JSAMPROW ptr;
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register JSAMPLE *rescale = source->rescale;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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*ptr++ = rescale[read_pbm_integer(cinfo, infile)];
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METHODDEF(JDIMENSION)
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get_text_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading text-format PPM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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FILE * infile = source->pub.input_file;
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register JSAMPROW ptr;
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register JSAMPLE *rescale = source->rescale;
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ptr = source->pub.buffer[0];
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for (col = cinfo->image_width; col > 0; col--) {
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*ptr++ = rescale[read_pbm_integer(cinfo, infile)];
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*ptr++ = rescale[read_pbm_integer(cinfo, infile)];
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*ptr++ = rescale[read_pbm_integer(cinfo, infile)];
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METHODDEF(JDIMENSION)
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get_scaled_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading raw-byte-format PGM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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register JSAMPROW ptr;
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register U_CHAR * bufferptr;
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register JSAMPLE *rescale = source->rescale;
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if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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ptr = source->pub.buffer[0];
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bufferptr = source->iobuffer;
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for (col = cinfo->image_width; col > 0; col--) {
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*ptr++ = rescale[UCH(*bufferptr++)];
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METHODDEF(JDIMENSION)
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get_scaled_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading raw-byte-format PPM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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register JSAMPROW ptr;
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register U_CHAR * bufferptr;
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register JSAMPLE *rescale = source->rescale;
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if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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ptr = source->pub.buffer[0];
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bufferptr = source->iobuffer;
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for (col = cinfo->image_width; col > 0; col--) {
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*ptr++ = rescale[UCH(*bufferptr++)];
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*ptr++ = rescale[UCH(*bufferptr++)];
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*ptr++ = rescale[UCH(*bufferptr++)];
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METHODDEF(JDIMENSION)
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get_raw_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading raw-byte-format files with maxval = MAXJSAMPLE.
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* In this case we just read right into the JSAMPLE buffer!
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* Note that same code works for PPM and PGM files.
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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METHODDEF(JDIMENSION)
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get_word_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading raw-word-format PGM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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register JSAMPROW ptr;
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register U_CHAR * bufferptr;
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register JSAMPLE *rescale = source->rescale;
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if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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ptr = source->pub.buffer[0];
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bufferptr = source->iobuffer;
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for (col = cinfo->image_width; col > 0; col--) {
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temp = UCH(*bufferptr++) << 8;
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temp |= UCH(*bufferptr++);
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*ptr++ = rescale[temp];
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METHODDEF(JDIMENSION)
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get_word_rgb_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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/* This version is for reading raw-word-format PPM files with any maxval */
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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register JSAMPROW ptr;
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register U_CHAR * bufferptr;
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register JSAMPLE *rescale = source->rescale;
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if (! ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
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ERREXIT(cinfo, JERR_INPUT_EOF);
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ptr = source->pub.buffer[0];
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bufferptr = source->iobuffer;
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for (col = cinfo->image_width; col > 0; col--) {
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temp = UCH(*bufferptr++) << 8;
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temp |= UCH(*bufferptr++);
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*ptr++ = rescale[temp];
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temp = UCH(*bufferptr++) << 8;
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temp |= UCH(*bufferptr++);
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*ptr++ = rescale[temp];
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temp = UCH(*bufferptr++) << 8;
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temp |= UCH(*bufferptr++);
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*ptr++ = rescale[temp];
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* Read the file header; return image size and component count.
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start_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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ppm_source_ptr source = (ppm_source_ptr) sinfo;
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unsigned int w, h, maxval;
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boolean need_iobuffer, use_raw_buffer, need_rescale;
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if (getc(source->pub.input_file) != 'P')
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ERREXIT(cinfo, JERR_PPM_NOT);
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c = getc(source->pub.input_file); /* subformat discriminator character */
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/* detect unsupported variants (ie, PBM) before trying to read header */
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case '2': /* it's a text-format PGM file */
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case '3': /* it's a text-format PPM file */
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case '5': /* it's a raw-format PGM file */
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case '6': /* it's a raw-format PPM file */
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ERREXIT(cinfo, JERR_PPM_NOT);
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/* fetch the remaining header info */
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w = read_pbm_integer(cinfo, source->pub.input_file);
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h = read_pbm_integer(cinfo, source->pub.input_file);
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maxval = read_pbm_integer(cinfo, source->pub.input_file);
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if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
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ERREXIT(cinfo, JERR_PPM_NOT);
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cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */
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cinfo->image_width = (JDIMENSION) w;
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cinfo->image_height = (JDIMENSION) h;
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/* initialize flags to most common settings */
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need_iobuffer = TRUE; /* do we need an I/O buffer? */
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use_raw_buffer = FALSE; /* do we map input buffer onto I/O buffer? */
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need_rescale = TRUE; /* do we need a rescale array? */
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case '2': /* it's a text-format PGM file */
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cinfo->input_components = 1;
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cinfo->in_color_space = JCS_GRAYSCALE;
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TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);
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source->pub.get_pixel_rows = get_text_gray_row;
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need_iobuffer = FALSE;
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case '3': /* it's a text-format PPM file */
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cinfo->input_components = 3;
349
cinfo->in_color_space = JCS_RGB;
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TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);
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source->pub.get_pixel_rows = get_text_rgb_row;
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need_iobuffer = FALSE;
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case '5': /* it's a raw-format PGM file */
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cinfo->input_components = 1;
357
cinfo->in_color_space = JCS_GRAYSCALE;
358
TRACEMS2(cinfo, 1, JTRC_PGM, w, h);
360
source->pub.get_pixel_rows = get_word_gray_row;
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} else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
362
source->pub.get_pixel_rows = get_raw_row;
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use_raw_buffer = TRUE;
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need_rescale = FALSE;
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source->pub.get_pixel_rows = get_scaled_gray_row;
370
case '6': /* it's a raw-format PPM file */
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cinfo->input_components = 3;
372
cinfo->in_color_space = JCS_RGB;
373
TRACEMS2(cinfo, 1, JTRC_PPM, w, h);
375
source->pub.get_pixel_rows = get_word_rgb_row;
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} else if (maxval == MAXJSAMPLE && SIZEOF(JSAMPLE) == SIZEOF(U_CHAR)) {
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source->pub.get_pixel_rows = get_raw_row;
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use_raw_buffer = TRUE;
379
need_rescale = FALSE;
381
source->pub.get_pixel_rows = get_scaled_rgb_row;
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/* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
388
source->buffer_width = (size_t) w * cinfo->input_components *
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((maxval<=255) ? SIZEOF(U_CHAR) : (2*SIZEOF(U_CHAR)));
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source->iobuffer = (U_CHAR *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
392
source->buffer_width);
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/* Create compressor input buffer. */
396
if (use_raw_buffer) {
397
/* For unscaled raw-input case, we can just map it onto the I/O buffer. */
398
/* Synthesize a JSAMPARRAY pointer structure */
399
/* Cast here implies near->far pointer conversion on PCs */
400
source->pixrow = (JSAMPROW) source->iobuffer;
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source->pub.buffer = & source->pixrow;
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source->pub.buffer_height = 1;
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/* Need to translate anyway, so make a separate sample buffer. */
405
source->pub.buffer = (*cinfo->mem->alloc_sarray)
406
((j_common_ptr) cinfo, JPOOL_IMAGE,
407
(JDIMENSION) w * cinfo->input_components, (JDIMENSION) 1);
408
source->pub.buffer_height = 1;
411
/* Compute the rescaling array if required. */
413
INT32 val, half_maxval;
415
/* On 16-bit-int machines we have to be careful of maxval = 65535 */
416
source->rescale = (JSAMPLE *)
417
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
418
(size_t) (((long) maxval + 1L) * SIZEOF(JSAMPLE)));
419
half_maxval = maxval / 2;
420
for (val = 0; val <= (INT32) maxval; val++) {
421
/* The multiplication here must be done in 32 bits to avoid overflow */
422
source->rescale[val] = (JSAMPLE) ((val*MAXJSAMPLE + half_maxval)/maxval);
429
* Finish up at the end of the file.
433
finish_input_ppm (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
440
* The module selection routine for PPM format input.
443
GLOBAL(cjpeg_source_ptr)
444
jinit_read_ppm (j_compress_ptr cinfo)
446
ppm_source_ptr source;
448
/* Create module interface object */
449
source = (ppm_source_ptr)
450
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
451
SIZEOF(ppm_source_struct));
452
/* Fill in method ptrs, except get_pixel_rows which start_input sets */
453
source->pub.start_input = start_input_ppm;
454
source->pub.finish_input = finish_input_ppm;
456
return (cjpeg_source_ptr) source;
459
#endif /* PPM_SUPPORTED */
added
removed
jpg/rdppm.c
