diff options
Diffstat (limited to 'tdefile-plugins/jpeg/tdefile_setcomment.cpp')
| -rw-r--r-- | tdefile-plugins/jpeg/tdefile_setcomment.cpp | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/tdefile-plugins/jpeg/tdefile_setcomment.cpp b/tdefile-plugins/jpeg/tdefile_setcomment.cpp new file mode 100644 index 00000000..07dca273 --- /dev/null +++ b/tdefile-plugins/jpeg/tdefile_setcomment.cpp @@ -0,0 +1,536 @@ +/* + * setcomment.cpp + * + * Copyright 2002 Bryce Nesbitt + * + * Based on wrjpgcom.c, Copyright (C) 1994-1997, Thomas G. Lane. + * Part of the Independent JPEG Group's software release 6b of 27-Mar-1998 + * + * This file contains a very simple stand-alone application that inserts + * user-supplied text as a COM (comment) marker in a JPEG/JFIF file. + * This may be useful as an example of the minimum logic needed to parse + * JPEG markers. + * + * There can be an arbitrary number of COM blocks in each jpeg file, with + * up to 64K of data each. We, however, write just one COM and blow away + * the rest. + * + ***************** + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License as published by the Free Software Foundation version 2. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, USA. + * + */ + +#undef STANDALONE_COMPILE + +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#include <string.h> +#include "config.h" + +extern int safe_copy_and_modify( const char * original_filename, const char * comment ); + +#ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ +#define READ_BINARY "r" +#define WRITE_BINARY "w" +#else +#ifdef VMS /* VMS is very nonstandard */ +#define READ_BINARY "rb", "ctx=stm" +#define WRITE_BINARY "wb", "ctx=stm" +#else /* standard ANSI-compliant case */ +#define READ_BINARY "rb" +#define WRITE_BINARY "wb" +#endif +#endif + +#define WARNING_GARBAGE 1 /* Original file had some unspecified content */ +#define ERROR_NOT_A_JPEG 5 /* Original file not a proper jpeg (must be 1st) */ +#define ERROR_TEMP_FILE 6 /* Problem writing temporay file */ +#define ERROR_SCREWUP 7 /* Original file is now damaged. Ooops. */ +#define ERROR_PREMATURE_EOF 8 /* Unexpected end of file */ +#define ERROR_BAD_MARKER 9 /* Marker with illegal length */ +#define ERROR_MARKER_ORDER 10 /* File seems to be mixed up */ + +static int global_error; /* global error flag. Once set, we're dead. */ + +/****************************************************************************/ +/* + * These macros are used to read the input file and write the output file. + * To reuse this code in another application, you might need to change these. + */ +static FILE * infile; /* input JPEG file */ + +/* Return next input byte, or EOF if no more */ +#define NEXTBYTE() getc(infile) + +static FILE * outfile; /* output JPEG file */ + +/* Emit an output byte */ +#define PUTBYTE(x) putc((x), outfile) + + +/****************************************************************************/ +/* Read one byte, testing for EOF */ +static int +read_1_byte (void) +{ + int c; + + c = NEXTBYTE(); + if (c == EOF) { + global_error = ERROR_PREMATURE_EOF; + } + return c; +} + +/* Read 2 bytes, convert to unsigned int */ +/* All 2-byte quantities in JPEG markers are MSB first */ +static unsigned int +read_2_bytes (void) +{ + int c1, c2; + + c1 = NEXTBYTE(); + if (c1 == EOF) + global_error = ERROR_PREMATURE_EOF; + c2 = NEXTBYTE(); + if (c2 == EOF) + global_error = ERROR_PREMATURE_EOF; + return (((unsigned int) c1) << 8) + ((unsigned int) c2); +} + + +/****************************************************************************/ +/* Routines to write data to output file */ +static void +write_1_byte (int c) +{ + PUTBYTE(c); +} + +static void +write_2_bytes (unsigned int val) +{ + PUTBYTE((val >> 8) & 0xFF); + PUTBYTE(val & 0xFF); +} + +static void +write_marker (int marker) +{ + PUTBYTE(0xFF); + PUTBYTE(marker); +} + +static void +copy_rest_of_file (void) +{ + int c; + + while ((c = NEXTBYTE()) != EOF) + PUTBYTE(c); +} + + +/****************************************************************************/ +/* + * JPEG markers consist of one or more 0xFF bytes, followed by a marker + * code byte (which is not an FF). Here are the marker codes of interest + * in this program. (See jdmarker.c for a more complete list.) + */ + +#define M_SOF0 0xC0 /* Start Of Frame N */ +#define M_SOF1 0xC1 /* N indicates which compression process */ +#define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */ +#define M_SOF3 0xC3 +#define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */ +#define M_SOF6 0xC6 +#define M_SOF7 0xC7 +#define M_SOF9 0xC9 +#define M_SOF10 0xCA +#define M_SOF11 0xCB +#define M_SOF13 0xCD +#define M_SOF14 0xCE +#define M_SOF15 0xCF +#define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */ +#define M_EOI 0xD9 /* End Of Image (end of datastream) */ +#define M_SOS 0xDA /* Start Of Scan (begins compressed data) */ +#define M_COM 0xFE /* COMment */ + + +/* + * Find the next JPEG marker and return its marker code. + * We expect at least one FF byte, possibly more if the compressor used FFs + * to pad the file. (Padding FFs will NOT be replicated in the output file.) + * There could also be non-FF garbage between markers. The treatment of such + * garbage is unspecified; we choose to skip over it but emit a warning msg. + * NB: this routine must not be used after seeing SOS marker, since it will + * not deal correctly with FF/00 sequences in the compressed image data... + */ +static int +next_marker (void) +{ + int c; + int discarded_bytes = 0; + + /* Find 0xFF byte; count and skip any non-FFs. */ + c = read_1_byte(); + while (c != 0xFF) { + discarded_bytes++; + c = read_1_byte(); + } + /* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs + * are legal as pad bytes, so don't count them in discarded_bytes. + */ + do { + c = read_1_byte(); + } while (c == 0xFF); + + if (discarded_bytes != 0) { + global_error = WARNING_GARBAGE; + } + + return c; +} + + +/* + * Most types of marker are followed by a variable-length parameter segment. + * This routine skips over the parameters for any marker we don't otherwise + * want to process. + * Note that we MUST skip the parameter segment explicitly in order not to + * be fooled by 0xFF bytes that might appear within the parameter segment; + * such bytes do NOT introduce new markers. + */ +static void +copy_variable (void) +/* Copy an unknown or uninteresting variable-length marker */ +{ + unsigned int length; + + /* Get the marker parameter length count */ + length = read_2_bytes(); + write_2_bytes(length); + /* Length includes itself, so must be at least 2 */ + if (length < 2) { + global_error = ERROR_BAD_MARKER; + length = 2; + } + length -= 2; + /* Skip over the remaining bytes */ + while (length > 0) { + write_1_byte(read_1_byte()); + length--; + } +} + +static void +skip_variable (void) +/* Skip over an unknown or uninteresting variable-length marker */ +{ + unsigned int length; + + /* Get the marker parameter length count */ + length = read_2_bytes(); + /* Length includes itself, so must be at least 2 */ + if (length < 2) { + global_error = ERROR_BAD_MARKER; + length = 2; + } + length -= 2; + /* Skip over the remaining bytes */ + while (length > 0) { + (void) read_1_byte(); + length--; + } +} + + +static int +scan_JPEG_header (int keep_COM) +/* + * Parse & copy the marker stream until SOFn or EOI is seen; + * copy data to output, but discard COM markers unless keep_COM is true. + */ +{ + int c1, c2; + int marker; + + /* + * Read the initial marker, which should be SOI. + * For a JFIF file, the first two bytes of the file should be literally + * 0xFF M_SOI. To be more general, we could use next_marker, but if the + * input file weren't actually JPEG at all, next_marker might read the whole + * file and then return a misleading error message... + */ + c1 = NEXTBYTE(); + c2 = NEXTBYTE(); + if (c1 != 0xFF || c2 != M_SOI) { + global_error = ERROR_NOT_A_JPEG; + return EOF; + } + + write_marker(M_SOI); + + /* Scan miscellaneous markers until we reach SOFn. */ + for (;;) { + marker = next_marker(); + switch (marker) { + /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be, + * treated as SOFn. C4 in particular is actually DHT. + */ + case M_SOF0: /* Baseline */ + case M_SOF1: /* Extended sequential, Huffman */ + case M_SOF2: /* Progressive, Huffman */ + case M_SOF3: /* Lossless, Huffman */ + case M_SOF5: /* Differential sequential, Huffman */ + case M_SOF6: /* Differential progressive, Huffman */ + case M_SOF7: /* Differential lossless, Huffman */ + case M_SOF9: /* Extended sequential, arithmetic */ + case M_SOF10: /* Progressive, arithmetic */ + case M_SOF11: /* Lossless, arithmetic */ + case M_SOF13: /* Differential sequential, arithmetic */ + case M_SOF14: /* Differential progressive, arithmetic */ + case M_SOF15: /* Differential lossless, arithmetic */ + return marker; + + case M_SOS: /* should not see compressed data before SOF */ + global_error = ERROR_MARKER_ORDER; + break; + + case M_EOI: /* in case it's a tables-only JPEG stream */ + return marker; + + case M_COM: /* Existing COM: conditionally discard */ + if (keep_COM) { + write_marker(marker); + copy_variable(); + } else { + skip_variable(); + } + break; + + default: /* Anything else just gets copied */ + write_marker(marker); + copy_variable(); /* we assume it has a parameter count... */ + break; + } + } /* end loop */ +} + + +/****************************************************************************/ +/* + Verify we know how to set the comment on this type of file. + + TODO: The actual check! This should verify + the image size promised in the headers matches the file, + and that all markers are properly formatted. +*/ +static int validate_image_file( const char * filename ) +{ +int status = 1; +int c1, c2; + + if ( (infile = fopen(filename, READ_BINARY)) ) { + c1 = NEXTBYTE(); + c2 = NEXTBYTE(); + if (c1 != 0xFF || c2 != M_SOI) + status = ERROR_NOT_A_JPEG; + else + status = 0; + fclose( infile ); + } + return( status ); +} + + +/****************************************************************************/ +/* + Modify the file in place, but be paranoid and safe about it. + It's worth a few extra CPU cycles to make sure we never + destory an original image: + 1) Validate the input file. + 2) Open a temporary file. + 3) Copy the data, writing a new comment block. + 4) Validate the temporary file. + 5) Move the temporary file over the original. + + To be even more paranoid & safe we could: + 5) Rename the original to a different temporary name. + 6) Rename the temporary to the original. + 7) Delete the original. +*/ +extern int safe_copy_and_modify( const char * original_filename, const char * comment ) +{ +char * temp_filename; +int temp_filename_length; +int comment_length = 0; +int marker; +int i; +struct stat statbuf; + + global_error = 0; + + /* + * Make sure we're dealing with a proper input file. Safety first! + */ + if( validate_image_file( original_filename ) ) { + fprintf(stderr, "error validating original file %s\n", original_filename); + return(ERROR_NOT_A_JPEG); + } + + /* Get a unique temporary file in the same directory. Hopefully + * if things go wrong, this file will still be left for recovery purposes. + * + * NB: I hate these stupid string functions in C... the buffer length is too + * hard to manage... + */ + outfile = NULL; + temp_filename_length = strlen( original_filename) + 4; + temp_filename = (char *)calloc( temp_filename_length, 1 ); + for( i=0; i<10; i++ ) { + snprintf( temp_filename, temp_filename_length, "%s%d", original_filename, i ); + if( stat( temp_filename, &statbuf ) ) { + outfile = fopen(temp_filename, WRITE_BINARY); + break; + } + } + if( !outfile ) { + fprintf(stderr, "failed opening temporary file %s\n", temp_filename); + free(temp_filename); + return(ERROR_TEMP_FILE); + } + + + /* + * Let's rock and roll! + */ + if ((infile = fopen(original_filename, READ_BINARY)) == NULL) { + fprintf(stderr, "can't open input file %s\n", original_filename); + free(temp_filename); + return(ERROR_NOT_A_JPEG); + } + /* 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(0); + /* Insert the new COM marker, but only if nonempty text has been supplied */ + if (comment) { + comment_length = strlen( comment ); + } + if (comment_length > 0) { + write_marker(M_COM); + write_2_bytes(comment_length + 2); + while (comment_length > 0) { + write_1_byte(*comment++); + comment_length--; + } + } + /* Duplicate the remainder of the source file. + * Note that any COM markers occurring after SOF will not be touched. + * + * :TODO: Discard COM markers occurring after SOF + */ + write_marker(marker); + copy_rest_of_file(); + fclose( infile ); + fsync( fileno( outfile) ); /* Make sure its really on disk first. !!!VERY IMPORTANT!!! */ + if ( fclose( outfile ) ) { + fprintf(stderr, "error in temporary file %s\n", temp_filename); + free(temp_filename); + return(ERROR_TEMP_FILE); + } + + + /* + * Make sure we did it right. We've already fsync()'ed the file. Safety first! + */ + if( validate_image_file( temp_filename ) ) { + fprintf(stderr, "error in temporary file %s\n", temp_filename); + free(temp_filename); + return(ERROR_TEMP_FILE); + } + + if( global_error >= ERROR_NOT_A_JPEG ) { + fprintf(stderr, "error %d processing %s\n", global_error, original_filename); + free(temp_filename); + return(ERROR_NOT_A_JPEG); + } + + if( rename( temp_filename, original_filename ) ) { + fprintf(stderr, "error renaming %s to %s\n", temp_filename, original_filename); + free(temp_filename); + return(ERROR_TEMP_FILE); + } + free(temp_filename); + + return(0); +} + + +#ifdef STANDALONE_COMPILE +int +main (int argc, char **argv) +{ + char * progname; /* program name for error messages */ + char * filename; + char * comment; + FILE * fp; + int error; + + /* Process command line arguments... */ + progname = argv[0]; + if (progname == NULL || progname[0] == 0) + progname = "writejpgcomment"; /* in case C library doesn't provide it */ + if( argc != 3) { + fprintf(stderr, "Usage: %s <filename> \"<comment>\"\nOverwrites the comment in a image file with the given comment.\n", progname); + return(5); + } + filename = argv[1]; + comment = argv[2]; + + + /* Check if file is readable... */ + if ((fp = fopen(filename, READ_BINARY)) == NULL) { + fprintf(stderr, "Error: Can't open file %s\n", filename); + fclose(fp); + return(5); + } + fclose(fp); + + /* Check if we really have a commentable image file here... */ + if( validate_image_file( filename ) ) { + fprintf(stderr, "Error: file %s is not of a supported type\n", filename); + return(5); + } + + /* Lets do it... modify the comment in place */ + if ((error = safe_copy_and_modify( filename, comment ) )) { + fprintf(stderr, "Error: %d setting jpg comment\n", error); + return(10); + } + + + /* TODO: Read comment back out of jpg and display it */ + return( 0 ); +} +#endif |