/* * rdppm.c * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1991-1997, Thomas G. Lane. * Modified 2009 by Bill Allombert, Guido Vollbeding. * libjpeg-turbo Modifications: * Copyright (C) 2015-2017, 2020-2023, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * 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 "cmyk.h" #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 */ U_CHAR; #define UCH(x) … #define ReadOK(file, buffer, len) … static int alpha_index[JPEG_NUMCS] = …; /* Private version of data source object */ 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 */ { … } LOCAL(unsigned int) read_pbm_integer(j_compress_ptr cinfo, FILE *infile, unsigned int maxval) /* 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. */ { … } /* * 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 */ { … } #define GRAY_RGB_READ_LOOP(read_op, alpha_set_op) … METHODDEF(JDIMENSION) get_text_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading text-format PGM files with any maxval and converting to extended RGB */ { … } METHODDEF(JDIMENSION) get_text_gray_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading text-format PGM files with any maxval and converting to CMYK */ { … } #define RGB_READ_LOOP(read_op, alpha_set_op) … 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 */ { … } METHODDEF(JDIMENSION) get_text_rgb_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading text-format PPM files with any maxval and converting to CMYK */ { … } 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 */ { … } METHODDEF(JDIMENSION) get_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading raw-byte-format PGM files with any maxval and converting to extended RGB */ { … } METHODDEF(JDIMENSION) get_gray_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading raw-byte-format PGM files with any maxval and converting to CMYK */ { … } METHODDEF(JDIMENSION) get_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading raw-byte-format PPM files with any maxval */ { … } METHODDEF(JDIMENSION) get_rgb_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) /* This version is for reading raw-byte-format PPM files with any maxval and converting to CMYK */ { … } 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. */ { … } 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 */ { … } 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 */ { … } /* * Read the file header; return image size and component count. */ METHODDEF(void) start_input_ppm(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) { … } /* * Finish up at the end of the file. */ METHODDEF(void) finish_input_ppm(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) { … } /* * The module selection routine for PPM format input. */ GLOBAL(cjpeg_source_ptr) jinit_read_ppm(j_compress_ptr cinfo) { … } #endif /* PPM_SUPPORTED */
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