diff options
Diffstat (limited to 'converter/pbm/macptopbm.c')
| -rw-r--r-- | converter/pbm/macptopbm.c | 426 |
1 files changed, 321 insertions, 105 deletions
diff --git a/converter/pbm/macptopbm.c b/converter/pbm/macptopbm.c index f4a341d3..db628b6c 100644 --- a/converter/pbm/macptopbm.c +++ b/converter/pbm/macptopbm.c @@ -1,6 +1,8 @@ /* macptopbm.c - read a MacPaint file and produce a portable bitmap ** ** Copyright (C) 1988 by Jef Poskanzer. +** Some code of ReadMacPaintFile() is based on the work of +** Patrick J. Naughton. (C) 1987, All Rights Reserved. ** ** Permission to use, copy, modify, and distribute this software and its ** documentation for any purpose and without fee is hereby granted, provided @@ -8,133 +10,347 @@ ** copyright notice and this permission notice appear in supporting ** documentation. This software is provided "as is" without express or ** implied warranty. + + +** Apr 2015 afu +** Changed code style (ANSI-style function definitions, etc.) +** Added automatic detection of MacBinary header. +** Added diagnostics for corruptions. +** Replaced byte-wise operations with bit-wise ones. */ #include "pbm.h" +#include "pm_c_util.h" #include "macp.h" -static void ReadMacPaintFile ARGS(( FILE* file, int extraskip, int* scanLineP, unsigned char Pic[MAX_LINES][BYTES_WIDE] )); -static unsigned char Pic[MAX_LINES][BYTES_WIDE]; + +static bool +validateMacPaintVersion( const unsigned char * const rBuff, + const int offset ) { +/*--------------------------------------------------------------------------- + Macpaint (or PNTG) files have two headers. + The 512 byte MacPaint header is mandatory. + The newer 128 byte MacBinary header is optional. If it exists, it comes + before the MacPaint header. + + Here we examine the first four bytes of the MacPaint header to get + the version number. + + Valid version numbers are 0, 2, 3. + We also allow 1. +-----------------------------------------------------------------------------*/ + + bool retval; + const unsigned char * const vNum = rBuff + offset; + + if ( ( ( vNum[0] | vNum[1] | vNum[2] ) != 0x00 ) || vNum[3] > 3 ) + retval = FALSE; + else + retval = TRUE; + + pm_message("MacPaint version (at offset %u): %02x %02x %02x %02x (%s)", + offset, vNum[0], vNum[1], vNum[2], vNum[3], + retval == TRUE ? "valid" : "not valid" ); + + return( retval ); +} + + + +static bool +scanMacBinaryHeader( const unsigned char * rBuff ) { +/*---------------------------------------------------------------------------- + We check byte 0 and 1, and then the MacPaint header version assuming it + starts at offset 128. + + Byte 0: must be 0x00. + Byte 1: (filename length) must be 1-63. + + Other fields that may be of interest: + + Bytes 2 through 63: (Internal Filename) + See Apple Charmap for valid characters. + Unlike US-Ascii, 8-bit characters (range 0x80 - 0xFF) are valid. + 0x00-0x1F and 0x7F are control characters. 0x00 appears in some files. + Colon ':' (0x3a) should be avoided in Mac environments but in practice + does appear. + + Bytes 65 through 68: (File Type) + Four Ascii characters. Should be "PNTG". + + Bytes 82 to 85: (SizeOfDataFork) + uint32 value. It seems this is file size (in bytes) / 256 + N, N <= 4. + + Bytes 100 through 124: + Should be all zero if the header is MacBinary I. + Defined and used in MacBinary II. + + Bytes 124,125: CRC + (MacBinary II only) CRC value of bytes 0 through 123. + + All multi-byte values are big-endian. + + Reference: + http://www.fileformat.info/format/macpaint/egff.htm + Fully describes the fields. However, the detection method described + does not work very well. + + Also see: + http://fileformats.archiveteam.org/wiki/MacPaint +-----------------------------------------------------------------------------*/ + bool foundMacBinaryHeader; + + /* Examine byte 0. It should be 0x00. Note that the first + byte of a valid MacPaint header should also be 0x00. + */ + if ( rBuff[0] != 0x00 ) { + foundMacBinaryHeader = FALSE; + } + + /* Examine byte 1, the length of the filename. + It should be in the range 1 - 63. + */ + else if( rBuff[1] == 0 || rBuff[1] > 63 ) { + foundMacBinaryHeader = FALSE; + } + + /* Check the MacPaint header version starting at offset 128. */ + else if ( validateMacPaintVersion ( rBuff, MACBIN_HEAD_LEN ) == FALSE) { + foundMacBinaryHeader = FALSE; + } + else + foundMacBinaryHeader = TRUE; + + if( foundMacBinaryHeader == TRUE) + pm_message("Input file contains a MacBinary header " + "followed by a MacPaint header."); + else + pm_message("Input file does not start with a MacBinary header."); + + return ( foundMacBinaryHeader ); +} + + + + +static void +skipHeader( FILE * const ifP ) { +/*-------------------------------------------------------------------------- + Determine whether the MacBinary header exists. + If it does, read off the initial 640 (=128 + 512) bytes of the file. + If it doesn't, read off 512 bytes. + + In the latter case we check the MacHeader version number, but just issue + a warning if the value is invalid. This is for backward comaptibility. +---------------------------------------------------------------------------*/ + unsigned int re; + const unsigned int buffsize = MAX( MACBIN_HEAD_LEN, MACP_HEAD_LEN ); + unsigned char * const rBuff = malloc(buffsize); + + if( rBuff == NULL ) + pm_error("Out of memory."); + + /* Read 512 bytes. + See if MacBinary header exists in the first 128 bytes and + the next 4 bytes signal the start of a MacPaint header. */ + re = fread ( rBuff, MACP_HEAD_LEN, 1, ifP); + if (re < 1) + pm_error("EOF/error while reading header."); + + if ( scanMacBinaryHeader( rBuff ) == TRUE ) { + /* MacBinary header found. Read another 128 bytes to complete the + MacPaint header, but don't conduct any further analysis. */ + re = fread ( rBuff, MACBIN_HEAD_LEN, 1, ifP); + if (re < 1) + pm_error("EOF/error while reading MacPaint header."); + + } else { + /* MacBinary header not found. We assume file starts with + MacPaint header. Check MacPaint version but dismiss error. */ + if (validateMacPaintVersion( rBuff, 0 ) == TRUE) + pm_message("Input file starts with valid MacPaint header."); + else + pm_message(" - Ignoring invalid version number."); + } + free( rBuff ); +} + + + +static void +skipExtraBytes( FILE * const ifP, + int const extraskip) { +/*-------------------------------------------------------------------------- + This function exists for backward compatibility. Its purpose is to + manually delete the MacBinary header. + + We check the MacHeader version number, but just issue a warning if the + value is invalid. +---------------------------------------------------------------------------*/ + unsigned int re; + unsigned char * const rBuff = malloc(MAX (extraskip, MACP_HEAD_LEN)); + + if( rBuff == NULL ) + pm_error("Out of memory."); + + re = fread ( rBuff, 1, extraskip, ifP); + if (re < extraskip) + pm_error("EOF/error while reading off initial %u bytes" + "specified by -extraskip.", extraskip); + re = fread ( rBuff, MACP_HEAD_LEN, 1, ifP); + if (re < 1) + pm_error("EOF/error while reading MacPaint header."); + + /* Check the MacPaint version number. Dismiss error. */ + if (validateMacPaintVersion( rBuff, 0 ) == TRUE) + pm_message("Input file starts with valid MacPaint header."); + else + pm_message(" - Ignoring invalid version number."); + + free( rBuff ); +} + + + +static unsigned char +readChar( FILE * const ifP ) { + + int const ch = getc( ifP ); + + if (ch ==EOF) + pm_error("EOF encountered while unpacking image data."); + + /* else */ + return ((unsigned char) ch); +} + + + + +static void +ReadMacPaintFile( FILE * const ifP, + int * outOfSyncP, + int * pixelCntP ) { +/*--------------------------------------------------------------------------- + Unpack image data. Compression method is called "Packbits". + This run-length encoding scheme has also been adopted by + Postscript and TIFF. See source: converter/other/pnmtops.c + + Unpacked raster array is raw PBM. No conversion is required. + + One source says flag byte should not be 0xFF (255), but we don't reject + the value, for in practice, it is widely used. + + Sequences should never cross row borders. + Violations of this rule are recorded in outOfSync. + + Note that pixelCnt counts bytes, not bits, so it is the number of pixels + multiplied by 8. This counter exists to detect corruptions. +---------------------------------------------------------------------------*/ + int pixelCnt = 0; /* Initial value */ + int outOfSync = 0; /* Initial value */ + unsigned int flag; /* Read from input */ + unsigned int i; + unsigned char * const bitrow = pbm_allocrow_packed(MACP_COLS); + + while ( pixelCnt < MACP_BYTES ) { + flag = (unsigned int) readChar( ifP ); /* Flag (count) byte */ + if ( flag < 0x80 ) { + /* Unpack next (flag + 1) chars as is */ + for ( i = 0; i <= flag; i++ ) + if( pixelCnt < MACP_BYTES) { + int const colChar = pixelCnt % MACP_COLCHARS; + pixelCnt++; + bitrow[colChar] = readChar( ifP ); + if (colChar == MACP_COLCHARS-1) + pbm_writepbmrow_packed( stdout, bitrow, MACP_COLS, 0 ); + if (colChar == 0 && i > 0 ) + outOfSync++; + } + } + else { + /* Repeat next char (2's complement of flagCnt) times */ + unsigned int const flagCnt = 256 - flag; + unsigned char const ch = readChar( ifP ); + for ( i = 0; i <= flagCnt; i++ ) + if( pixelCnt < MACP_BYTES) { + int const colChar = pixelCnt % MACP_COLCHARS; + pixelCnt++; + bitrow[colChar] = ch; + if (colChar == MACP_COLCHARS-1) + pbm_writepbmrow_packed( stdout, bitrow, MACP_COLS, 0 ); + if (colChar == 0 && i > 0 ) + outOfSync++; + } + } + } + pbm_freerow_packed ( bitrow ); + *outOfSyncP = outOfSync; + *pixelCntP = pixelCnt; +} + int -main( argc, argv ) - int argc; - char* argv[]; - { - FILE* ifp; - bit* bitrow; - int argn, extraskip, scanLine, rows, cols, row, bcol, i; - const char* usage = "[-extraskip N] [macpfile]"; +main( int argc, char * argv[]) { + FILE * ifp; + int argn, extraskip; + const char * const usage = "[-extraskip N] [macpfile]"; + int outOfSync; + int pixelCnt; pbm_init( &argc, argv ); - argn = 1; - extraskip = 0; + argn = 1; /* initial value */ + extraskip = 0; /* initial value */ /* Check for flags. */ - if ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' ) - { - if ( pm_keymatch( argv[argn], "-extraskip", 2 ) ) - { - argn++; - if ( argn == argc || sscanf( argv[argn], "%d", &extraskip ) != 1 ) - pm_usage( usage ); - } - else - pm_usage( usage ); - argn++; - } - - if ( argn < argc ) - { - ifp = pm_openr( argv[argn] ); - argn++; - } + if ( argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0' ) { + if ( pm_keymatch( argv[argn], "-extraskip", 2 ) ) { + argn++; + if ( argn == argc || sscanf( argv[argn], "%d", &extraskip ) != 1 ) + pm_usage( usage ); + } + else + pm_usage( usage ); + argn++; + } + + if ( argn < argc ) { + ifp = pm_openr( argv[argn] ); + argn++; + } else - ifp = stdin; + ifp = stdin; if ( argn != argc ) - pm_usage( usage ); + pm_usage( usage ); - ReadMacPaintFile( ifp, extraskip, &scanLine, Pic ); + if ( extraskip > 256 * 1024 ) + pm_error("-extraskip value too large"); + else if ( extraskip > 0 ) + skipExtraBytes( ifp, extraskip); + else + skipHeader( ifp ); + pbm_writepbminit( stdout, MACP_COLS, MACP_ROWS, 0 ); + + ReadMacPaintFile( ifp, &outOfSync, &pixelCnt ); + /* We may not be at EOF. + Macpaint files often have extra bytes after image data. */ pm_close( ifp ); - cols = BYTES_WIDE * 8; - rows = scanLine; - pbm_writepbminit( stdout, cols, rows, 0 ); - bitrow = pbm_allocrow( cols ); + if ( pixelCnt == 0 ) + pm_error("No image data."); + + else if ( pixelCnt < MACP_BYTES ) + pm_error("Compressed image data terminated prematurely."); - for ( row = 0; row < rows; row++ ) - { - for ( bcol = 0; bcol < BYTES_WIDE; bcol++ ) - for ( i = 0; i < 8; i++ ) - bitrow[bcol * 8 + i] = - ( (Pic[row][bcol] >> (7 - i)) & 1 ) ? PBM_BLACK : PBM_WHITE; - pbm_writepbmrow( stdout, bitrow, cols, 0 ); - } + else if ( outOfSync > 0 ) + pm_message("Warning: Corrupt image data. %d rows misaligned.", + outOfSync); pm_close( stdout ); exit( 0 ); - } - -/* -** Some of the following routine is: -** -** Copyright 1987 by Patrick J. Naughton -** All Rights Reserved -** 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. -*/ - -static void -ReadMacPaintFile( file, extraskip, scanLineP, Pic ) - FILE* file; - int extraskip; - int* scanLineP; - unsigned char Pic[MAX_LINES][BYTES_WIDE]; - { - unsigned int i, j, k; - unsigned char ch; - - /* Skip over the header. */ - for ( i = 0; i < extraskip; i++ ) - getc( file ); - for ( i = 0; i < HEADER_LENGTH; i++ ) - getc( file ); - - *scanLineP = 0; - k = 0; - - while ( *scanLineP < MAX_LINES ) - { - ch = (unsigned char) getc( file ); /* Count byte */ - i = (unsigned int) ch; - if ( ch < 0x80 ) - { /* Unpack next (I+1) chars as is */ - for ( j = 0; j <= i; j++ ) - if ( *scanLineP < MAX_LINES ) - { - Pic[*scanLineP][k++] = (unsigned char) getc( file ); - if ( ! (k %= BYTES_WIDE) ) - *scanLineP += 1; - } - } - else - { /* Repeat next char (2's comp I) times */ - ch = getc( file ); - for ( j = 0; j <= 256 - i; j++ ) - if ( *scanLineP < MAX_LINES ) - { - Pic[*scanLineP][k++] = (unsigned char) ch; - if ( ! (k %= BYTES_WIDE) ) - *scanLineP += 1; - } - } - } - } +} |