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583 lines
16 KiB
583 lines
16 KiB
/* |
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* wrjpgcom.c |
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* |
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* Copyright (C) 1994-1997, Thomas G. Lane. |
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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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* |
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* This file contains a very simple stand-alone application that inserts |
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* user-supplied text as a COM (comment) marker in a JFIF file. |
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* This may be useful as an example of the minimum logic needed to parse |
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* JPEG markers. |
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*/ |
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|
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#define JPEG_CJPEG_DJPEG /* to get the command-line config symbols */ |
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#include "jinclude.h" /* get auto-config symbols, <stdio.h> */ |
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#ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc() */ |
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extern void * malloc (); |
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#endif |
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#include <ctype.h> /* to declare isupper(), tolower() */ |
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#ifdef USE_SETMODE |
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#include <fcntl.h> /* to declare setmode()'s parameter macros */ |
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/* If you have setmode() but not <io.h>, just delete this line: */ |
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#include <io.h> /* to declare setmode() */ |
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#endif |
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#ifdef USE_CCOMMAND /* command-line reader for Macintosh */ |
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#ifdef __MWERKS__ |
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#include <SIOUX.h> /* Metrowerks needs this */ |
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#include <console.h> /* ... and this */ |
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#endif |
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#ifdef THINK_C |
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#include <console.h> /* Think declares it here */ |
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#endif |
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#endif |
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#ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ |
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#define READ_BINARY "r" |
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#define WRITE_BINARY "w" |
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#else |
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#ifdef VMS /* VMS is very nonstandard */ |
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#define READ_BINARY "rb", "ctx=stm" |
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#define WRITE_BINARY "wb", "ctx=stm" |
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#else /* standard ANSI-compliant case */ |
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#define READ_BINARY "rb" |
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#define WRITE_BINARY "wb" |
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#endif |
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#endif |
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#ifndef EXIT_FAILURE /* define exit() codes if not provided */ |
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#define EXIT_FAILURE 1 |
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#endif |
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#ifndef EXIT_SUCCESS |
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#ifdef VMS |
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#define EXIT_SUCCESS 1 /* VMS is very nonstandard */ |
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#else |
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#define EXIT_SUCCESS 0 |
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#endif |
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#endif |
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/* Reduce this value if your malloc() can't allocate blocks up to 64K. |
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* On DOS, compiling in large model is usually a better solution. |
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*/ |
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#ifndef MAX_COM_LENGTH |
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#define MAX_COM_LENGTH 65000L /* must be <= 65533 in any case */ |
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#endif |
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/* |
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* These macros are used to read the input file and write the output file. |
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* To reuse this code in another application, you might need to change these. |
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*/ |
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static FILE * infile; /* input JPEG file */ |
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|
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/* Return next input byte, or EOF if no more */ |
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#define NEXTBYTE() getc(infile) |
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static FILE * outfile; /* output JPEG file */ |
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/* Emit an output byte */ |
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#define PUTBYTE(x) putc((x), outfile) |
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/* Error exit handler */ |
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#define ERREXIT(msg) (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE)) |
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/* Read one byte, testing for EOF */ |
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static int |
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read_1_byte (void) |
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{ |
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int c; |
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c = NEXTBYTE(); |
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if (c == EOF) |
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ERREXIT("Premature EOF in JPEG file"); |
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return c; |
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} |
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/* Read 2 bytes, convert to unsigned int */ |
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/* All 2-byte quantities in JPEG markers are MSB first */ |
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static unsigned int |
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read_2_bytes (void) |
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{ |
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int c1, c2; |
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c1 = NEXTBYTE(); |
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if (c1 == EOF) |
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ERREXIT("Premature EOF in JPEG file"); |
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c2 = NEXTBYTE(); |
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if (c2 == EOF) |
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ERREXIT("Premature EOF in JPEG file"); |
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return (((unsigned int) c1) << 8) + ((unsigned int) c2); |
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} |
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/* Routines to write data to output file */ |
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static void |
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write_1_byte (int c) |
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{ |
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PUTBYTE(c); |
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} |
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static void |
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write_2_bytes (unsigned int val) |
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{ |
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PUTBYTE((val >> 8) & 0xFF); |
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PUTBYTE(val & 0xFF); |
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} |
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static void |
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write_marker (int marker) |
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{ |
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PUTBYTE(0xFF); |
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PUTBYTE(marker); |
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} |
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static void |
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copy_rest_of_file (void) |
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{ |
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int c; |
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while ((c = NEXTBYTE()) != EOF) |
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PUTBYTE(c); |
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} |
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/* |
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* JPEG markers consist of one or more 0xFF bytes, followed by a marker |
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* code byte (which is not an FF). Here are the marker codes of interest |
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* in this program. (See jdmarker.c for a more complete list.) |
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*/ |
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#define M_SOF0 0xC0 /* Start Of Frame N */ |
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#define M_SOF1 0xC1 /* N indicates which compression process */ |
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#define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */ |
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#define M_SOF3 0xC3 |
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#define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */ |
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#define M_SOF6 0xC6 |
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#define M_SOF7 0xC7 |
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#define M_SOF9 0xC9 |
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#define M_SOF10 0xCA |
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#define M_SOF11 0xCB |
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#define M_SOF13 0xCD |
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#define M_SOF14 0xCE |
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#define M_SOF15 0xCF |
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#define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */ |
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#define M_EOI 0xD9 /* End Of Image (end of datastream) */ |
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#define M_SOS 0xDA /* Start Of Scan (begins compressed data) */ |
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#define M_COM 0xFE /* COMment */ |
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/* |
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* Find the next JPEG marker and return its marker code. |
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* We expect at least one FF byte, possibly more if the compressor used FFs |
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* to pad the file. (Padding FFs will NOT be replicated in the output file.) |
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* There could also be non-FF garbage between markers. The treatment of such |
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* garbage is unspecified; we choose to skip over it but emit a warning msg. |
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* NB: this routine must not be used after seeing SOS marker, since it will |
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* not deal correctly with FF/00 sequences in the compressed image data... |
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*/ |
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static int |
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next_marker (void) |
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{ |
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int c; |
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int discarded_bytes = 0; |
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/* Find 0xFF byte; count and skip any non-FFs. */ |
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c = read_1_byte(); |
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while (c != 0xFF) { |
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discarded_bytes++; |
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c = read_1_byte(); |
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} |
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/* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs |
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* are legal as pad bytes, so don't count them in discarded_bytes. |
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*/ |
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do { |
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c = read_1_byte(); |
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} while (c == 0xFF); |
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if (discarded_bytes != 0) { |
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fprintf(stderr, "Warning: garbage data found in JPEG file\n"); |
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} |
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return c; |
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} |
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/* |
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* Read the initial marker, which should be SOI. |
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* For a JFIF file, the first two bytes of the file should be literally |
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* 0xFF M_SOI. To be more general, we could use next_marker, but if the |
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* input file weren't actually JPEG at all, next_marker might read the whole |
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* file and then return a misleading error message... |
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*/ |
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static int |
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first_marker (void) |
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{ |
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int c1, c2; |
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c1 = NEXTBYTE(); |
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c2 = NEXTBYTE(); |
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if (c1 != 0xFF || c2 != M_SOI) |
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ERREXIT("Not a JPEG file"); |
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return c2; |
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} |
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/* |
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* Most types of marker are followed by a variable-length parameter segment. |
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* This routine skips over the parameters for any marker we don't otherwise |
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* want to process. |
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* Note that we MUST skip the parameter segment explicitly in order not to |
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* be fooled by 0xFF bytes that might appear within the parameter segment; |
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* such bytes do NOT introduce new markers. |
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*/ |
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static void |
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copy_variable (void) |
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/* Copy an unknown or uninteresting variable-length marker */ |
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{ |
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unsigned int length; |
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/* Get the marker parameter length count */ |
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length = read_2_bytes(); |
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write_2_bytes(length); |
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/* Length includes itself, so must be at least 2 */ |
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if (length < 2) |
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ERREXIT("Erroneous JPEG marker length"); |
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length -= 2; |
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/* Skip over the remaining bytes */ |
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while (length > 0) { |
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write_1_byte(read_1_byte()); |
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length--; |
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} |
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} |
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static void |
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skip_variable (void) |
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/* Skip over an unknown or uninteresting variable-length marker */ |
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{ |
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unsigned int length; |
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/* Get the marker parameter length count */ |
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length = read_2_bytes(); |
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/* Length includes itself, so must be at least 2 */ |
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if (length < 2) |
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ERREXIT("Erroneous JPEG marker length"); |
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length -= 2; |
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/* Skip over the remaining bytes */ |
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while (length > 0) { |
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(void) read_1_byte(); |
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length--; |
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} |
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} |
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/* |
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* Parse the marker stream until SOFn or EOI is seen; |
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* copy data to output, but discard COM markers unless keep_COM is true. |
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*/ |
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static int |
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scan_JPEG_header (int keep_COM) |
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{ |
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int marker; |
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/* Expect SOI at start of file */ |
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if (first_marker() != M_SOI) |
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ERREXIT("Expected SOI marker first"); |
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write_marker(M_SOI); |
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/* Scan miscellaneous markers until we reach SOFn. */ |
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for (;;) { |
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marker = next_marker(); |
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switch (marker) { |
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/* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be, |
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* treated as SOFn. C4 in particular is actually DHT. |
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*/ |
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case M_SOF0: /* Baseline */ |
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case M_SOF1: /* Extended sequential, Huffman */ |
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case M_SOF2: /* Progressive, Huffman */ |
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case M_SOF3: /* Lossless, Huffman */ |
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case M_SOF5: /* Differential sequential, Huffman */ |
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case M_SOF6: /* Differential progressive, Huffman */ |
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case M_SOF7: /* Differential lossless, Huffman */ |
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case M_SOF9: /* Extended sequential, arithmetic */ |
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case M_SOF10: /* Progressive, arithmetic */ |
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case M_SOF11: /* Lossless, arithmetic */ |
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case M_SOF13: /* Differential sequential, arithmetic */ |
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case M_SOF14: /* Differential progressive, arithmetic */ |
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case M_SOF15: /* Differential lossless, arithmetic */ |
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return marker; |
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case M_SOS: /* should not see compressed data before SOF */ |
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ERREXIT("SOS without prior SOFn"); |
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break; |
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case M_EOI: /* in case it's a tables-only JPEG stream */ |
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return marker; |
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case M_COM: /* Existing COM: conditionally discard */ |
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if (keep_COM) { |
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write_marker(marker); |
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copy_variable(); |
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} else { |
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skip_variable(); |
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} |
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break; |
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default: /* Anything else just gets copied */ |
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write_marker(marker); |
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copy_variable(); /* we assume it has a parameter count... */ |
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break; |
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} |
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} /* end loop */ |
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} |
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/* Command line parsing code */ |
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static const char * progname; /* program name for error messages */ |
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static void |
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usage (void) |
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/* complain about bad command line */ |
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{ |
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fprintf(stderr, "wrjpgcom inserts a textual comment in a JPEG file.\n"); |
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fprintf(stderr, "You can add to or replace any existing comment(s).\n"); |
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fprintf(stderr, "Usage: %s [switches] ", progname); |
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#ifdef TWO_FILE_COMMANDLINE |
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fprintf(stderr, "inputfile outputfile\n"); |
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#else |
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fprintf(stderr, "[inputfile]\n"); |
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#endif |
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fprintf(stderr, "Switches (names may be abbreviated):\n"); |
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fprintf(stderr, " -replace Delete any existing comments\n"); |
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fprintf(stderr, " -comment \"text\" Insert comment with given text\n"); |
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fprintf(stderr, " -cfile name Read comment from named file\n"); |
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fprintf(stderr, "Notice that you must put quotes around the comment text\n"); |
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fprintf(stderr, "when you use -comment.\n"); |
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fprintf(stderr, "If you do not give either -comment or -cfile on the command line,\n"); |
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fprintf(stderr, "then the comment text is read from standard input.\n"); |
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fprintf(stderr, "It can be multiple lines, up to %u characters total.\n", |
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(unsigned int) MAX_COM_LENGTH); |
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#ifndef TWO_FILE_COMMANDLINE |
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fprintf(stderr, "You must specify an input JPEG file name when supplying\n"); |
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fprintf(stderr, "comment text from standard input.\n"); |
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#endif |
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exit(EXIT_FAILURE); |
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} |
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static int |
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keymatch (char * arg, const char * keyword, int minchars) |
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/* Case-insensitive matching of (possibly abbreviated) keyword switches. */ |
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/* keyword is the constant keyword (must be lower case already), */ |
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/* minchars is length of minimum legal abbreviation. */ |
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{ |
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register int ca, ck; |
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register int nmatched = 0; |
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|
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while ((ca = *arg++) != '\0') { |
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if ((ck = *keyword++) == '\0') |
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return 0; /* arg longer than keyword, no good */ |
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if (isupper(ca)) /* force arg to lcase (assume ck is already) */ |
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ca = tolower(ca); |
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if (ca != ck) |
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return 0; /* no good */ |
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nmatched++; /* count matched characters */ |
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} |
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/* reached end of argument; fail if it's too short for unique abbrev */ |
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if (nmatched < minchars) |
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return 0; |
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return 1; /* A-OK */ |
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} |
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/* |
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* The main program. |
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*/ |
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|
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int |
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main (int argc, char **argv) |
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{ |
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int argn; |
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char * arg; |
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int keep_COM = 1; |
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char * comment_arg = NULL; |
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FILE * comment_file = NULL; |
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unsigned int comment_length = 0; |
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int marker; |
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|
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/* On Mac, fetch a command line. */ |
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#ifdef USE_CCOMMAND |
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argc = ccommand(&argv); |
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#endif |
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|
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progname = argv[0]; |
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if (progname == NULL || progname[0] == 0) |
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progname = "wrjpgcom"; /* in case C library doesn't provide it */ |
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|
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/* Parse switches, if any */ |
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for (argn = 1; argn < argc; argn++) { |
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arg = argv[argn]; |
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if (arg[0] != '-') |
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break; /* not switch, must be file name */ |
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arg++; /* advance over '-' */ |
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if (keymatch(arg, "replace", 1)) { |
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keep_COM = 0; |
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} else if (keymatch(arg, "cfile", 2)) { |
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if (++argn >= argc) usage(); |
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if ((comment_file = fopen(argv[argn], "r")) == NULL) { |
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fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); |
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exit(EXIT_FAILURE); |
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} |
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} else if (keymatch(arg, "comment", 1)) { |
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if (++argn >= argc) usage(); |
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comment_arg = argv[argn]; |
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/* If the comment text starts with '"', then we are probably running |
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* under MS-DOG and must parse out the quoted string ourselves. Sigh. |
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*/ |
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if (comment_arg[0] == '"') { |
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comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); |
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if (comment_arg == NULL) |
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ERREXIT("Insufficient memory"); |
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strcpy(comment_arg, argv[argn]+1); |
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for (;;) { |
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comment_length = (unsigned int) strlen(comment_arg); |
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if (comment_length > 0 && comment_arg[comment_length-1] == '"') { |
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comment_arg[comment_length-1] = '\0'; /* zap terminating quote */ |
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break; |
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} |
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if (++argn >= argc) |
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ERREXIT("Missing ending quote mark"); |
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strcat(comment_arg, " "); |
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strcat(comment_arg, argv[argn]); |
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} |
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} |
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comment_length = (unsigned int) strlen(comment_arg); |
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} else |
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usage(); |
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} |
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|
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/* Cannot use both -comment and -cfile. */ |
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if (comment_arg != NULL && comment_file != NULL) |
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usage(); |
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/* If there is neither -comment nor -cfile, we will read the comment text |
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* from stdin; in this case there MUST be an input JPEG file name. |
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*/ |
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if (comment_arg == NULL && comment_file == NULL && argn >= argc) |
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usage(); |
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|
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/* Open the input file. */ |
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if (argn < argc) { |
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if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) { |
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fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); |
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exit(EXIT_FAILURE); |
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} |
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} else { |
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/* default input file is stdin */ |
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#ifdef USE_SETMODE /* need to hack file mode? */ |
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setmode(fileno(stdin), O_BINARY); |
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#endif |
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#ifdef USE_FDOPEN /* need to re-open in binary mode? */ |
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if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) { |
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fprintf(stderr, "%s: can't open stdin\n", progname); |
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exit(EXIT_FAILURE); |
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} |
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#else |
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infile = stdin; |
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#endif |
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} |
|
|
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/* Open the output file. */ |
|
#ifdef TWO_FILE_COMMANDLINE |
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/* Must have explicit output file name */ |
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if (argn != argc-2) { |
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fprintf(stderr, "%s: must name one input and one output file\n", |
|
progname); |
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usage(); |
|
} |
|
if ((outfile = fopen(argv[argn+1], WRITE_BINARY)) == NULL) { |
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fprintf(stderr, "%s: can't open %s\n", progname, argv[argn+1]); |
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exit(EXIT_FAILURE); |
|
} |
|
#else |
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/* Unix style: expect zero or one file name */ |
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if (argn < argc-1) { |
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fprintf(stderr, "%s: only one input file\n", progname); |
|
usage(); |
|
} |
|
/* default output file is stdout */ |
|
#ifdef USE_SETMODE /* need to hack file mode? */ |
|
setmode(fileno(stdout), O_BINARY); |
|
#endif |
|
#ifdef USE_FDOPEN /* need to re-open in binary mode? */ |
|
if ((outfile = fdopen(fileno(stdout), WRITE_BINARY)) == NULL) { |
|
fprintf(stderr, "%s: can't open stdout\n", progname); |
|
exit(EXIT_FAILURE); |
|
} |
|
#else |
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outfile = stdout; |
|
#endif |
|
#endif /* TWO_FILE_COMMANDLINE */ |
|
|
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/* Collect comment text from comment_file or stdin, if necessary */ |
|
if (comment_arg == NULL) { |
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FILE * src_file; |
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int c; |
|
|
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comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); |
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if (comment_arg == NULL) |
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ERREXIT("Insufficient memory"); |
|
comment_length = 0; |
|
src_file = (comment_file != NULL ? comment_file : stdin); |
|
while ((c = getc(src_file)) != EOF) { |
|
if (comment_length >= (unsigned int) MAX_COM_LENGTH) { |
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fprintf(stderr, "Comment text may not exceed %u bytes\n", |
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(unsigned int) MAX_COM_LENGTH); |
|
exit(EXIT_FAILURE); |
|
} |
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comment_arg[comment_length++] = (char) c; |
|
} |
|
if (comment_file != NULL) |
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fclose(comment_file); |
|
} |
|
|
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/* Copy JPEG headers until SOFn marker; |
|
* we will insert the new comment marker just before SOFn. |
|
* This (a) causes the new comment to appear after, rather than before, |
|
* existing comments; and (b) ensures that comments come after any JFIF |
|
* or JFXX markers, as required by the JFIF specification. |
|
*/ |
|
marker = scan_JPEG_header(keep_COM); |
|
/* Insert the new COM marker, but only if nonempty text has been supplied */ |
|
if (comment_length > 0) { |
|
write_marker(M_COM); |
|
write_2_bytes(comment_length + 2); |
|
while (comment_length > 0) { |
|
write_1_byte(*comment_arg++); |
|
comment_length--; |
|
} |
|
} |
|
/* Duplicate the remainder of the source file. |
|
* Note that any COM markers occuring after SOF will not be touched. |
|
*/ |
|
write_marker(marker); |
|
copy_rest_of_file(); |
|
|
|
/* All done. */ |
|
exit(EXIT_SUCCESS); |
|
return 0; /* suppress no-return-value warnings */ |
|
}
|
|
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