JPEGView/Independent JPEG Group/cjpeg.c

/*
 * cjpeg.c
 *
 * Copyright (C) 1991-1994, 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 a command-line user interface for the JPEG compressor.
 * It should work on any system with Unix- or MS-DOS-style command lines.
 *
 * Two different command line styles are permitted, depending on the
 * compile-time switch TWO_FILE_COMMANDLINE:
 *	cjpeg [options]  inputfile outputfile
 *	cjpeg [options]  [inputfile]
 * In the second style, output is always to standard output, which you'd
 * normally redirect to a file or pipe to some other program.  Input is
 * either from a named file or from standard input (typically redirected).
 * The second style is convenient on Unix but is unhelpful on systems that
 * don't support pipes.  Also, you MUST use the first style if your system
 * doesn't do binary I/O to stdin/stdout.
 * To simplify script writing, the "-outfile" switch is provided.  The syntax
 *	cjpeg [options]  -outfile outputfile  inputfile
 * works regardless of which command line style is used.
 */

#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
#define JMAKE_MSG_TABLE
#include "cderror.h"		/* create message string table */
#include "jversion.h"		/* for version message */

#include <ctype.h>		/* to declare isupper(), tolower() */
#ifdef NEED_SIGNAL_CATCHER
#include <signal.h>		/* to declare signal() */
#endif
#ifdef USE_SETMODE
#include <fcntl.h>		/* to declare setmode() */
#endif

#ifdef THINK_C
#include <console.h>		/* command-line reader for Macintosh */
#endif

#ifdef DONT_USE_B_MODE		/* define mode parameters for fopen() */
#define READ_BINARY	"r"
#define WRITE_BINARY	"w"
#else
#define READ_BINARY	"rb"
#define WRITE_BINARY	"wb"
#endif

#ifndef EXIT_FAILURE		/* define exit() codes if not provided */
#define EXIT_FAILURE  1
#endif
#ifndef EXIT_SUCCESS
#ifdef VMS
#define EXIT_SUCCESS  1		/* VMS is very nonstandard */
#else
#define EXIT_SUCCESS  0
#endif
#endif
#ifndef EXIT_WARNING
#ifdef VMS
#define EXIT_WARNING  1		/* VMS is very nonstandard */
#else
#define EXIT_WARNING  2
#endif
#endif


/*
 * This routine determines what format the input file is,
 * and selects the appropriate input-reading module.
 *
 * To determine which family of input formats the file belongs to,
 * we may look only at the first byte of the file, since C does not
 * guarantee that more than one character can be pushed back with ungetc.
 * Looking at additional bytes would require one of these approaches:
 *     1) assume we can fseek() the input file (fails for piped input);
 *     2) assume we can push back more than one character (works in
 *        some C implementations, but unportable);
 *     3) provide our own buffering (breaks input readers that want to use
 *        stdio directly, such as the RLE library);
 * or  4) don't put back the data, and modify the input_init methods to assume
 *        they start reading after the start of file (also breaks RLE library).
 * #1 is attractive for MS-DOS but is untenable on Unix.
 *
 * The most portable solution for file types that can't be identified by their
 * first byte is to make the user tell us what they are.  This is also the
 * only approach for "raw" file types that contain only arbitrary values.
 * We presently apply this method for Targa files.  Most of the time Targa
 * files start with 0x00, so we recognize that case.  Potentially, however,
 * a Targa file could start with any byte value (byte 0 is the length of the
 * seldom-used ID field), so we provide a switch to force Targa input mode.
 */

static boolean is_targa;	/* records user -targa switch */


LOCAL cjpeg_source_ptr
select_file_type (j_compress_ptr cinfo, FILE * infile)
{
  int c;

  if (is_targa) {
#ifdef TARGA_SUPPORTED
    return jinit_read_targa(cinfo);
#else
    ERREXIT(cinfo, JERR_TGA_NOTCOMP);
#endif
  }

  if ((c = getc(infile)) == EOF)
    ERREXIT(cinfo, JERR_INPUT_EMPTY);
  if (ungetc(c, infile) == EOF)
    ERREXIT(cinfo, JERR_UNGETC_FAILED);

  switch (c) {