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/* ybmtopbm.c - read a file from Bennet Yee's 'xbm' program and write a pbm.
**
** Written by Jamie Zawinski based on code (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.
*/
#include <stdio.h>
#include "pbm.h"
static void getinit ARGS(( FILE* file, short* colsP, short* rowsP, short* depthP, short* padrightP ));
static bit getbit ARGS(( FILE* file ));
#define YBM_MAGIC ( ( '!' << 8 ) | '!' )
int
main( argc, argv )
int argc;
char* argv[];
{
FILE* ifp;
bit* bitrow;
register bit* bP;
short rows, cols, padright, row, col;
short depth;
pbm_init( &argc, argv );
if ( argc > 2 )
pm_usage( "[ybmfile]" );
if ( argc == 2 )
ifp = pm_openr( argv[1] );
else
ifp = stdin;
getinit( ifp, &cols, &rows, &depth, &padright );
if ( depth != 1 )
pm_error(
"YBM file has depth of %d, must be 1",
(int) depth );
pbm_writepbminit( stdout, cols, rows, 0 );
bitrow = pbm_allocrow( cols );
for ( row = 0; row < rows; ++row )
{
/* Get data. */
for ( col = 0, bP = bitrow; col < cols; ++col, ++bP )
*bP = getbit( ifp );
/* Discard line padding */
for ( col = 0; col < padright; ++col )
(void) getbit( ifp );
pbm_writepbmrow( stdout, bitrow, cols, 0 );
}
pm_close( ifp );
pm_close( stdout );
exit( 0 );
}
static int item;
static int bitsperitem, bitshift;
static void
getinit( file, colsP, rowsP, depthP, padrightP )
FILE* file;
short* colsP;
short* rowsP;
short* depthP;
short* padrightP;
{
short magic;
if ( pm_readbigshort( file, &magic ) == -1 )
pm_error( "EOF / read error" );
if ( magic != YBM_MAGIC )
pm_error( "bad magic number in YBM file" );
if ( pm_readbigshort( file, colsP ) == -1 )
pm_error( "EOF / read error" );
if ( pm_readbigshort( file, rowsP ) == -1 )
pm_error( "EOF / read error" );
*depthP = 1;
*padrightP = ( ( *colsP + 15 ) / 16 ) * 16 - *colsP;
bitsperitem = 0;
}
static bit
getbit( file )
FILE* file;
{
bit b;
if ( bitsperitem == 0 )
{
item = getc(file) | getc(file)<<8;
if ( item == EOF )
pm_error( "EOF / read error" );
bitsperitem = 16;
bitshift = 0;
}
b = ( ( item >> bitshift) & 1 ) ? PBM_BLACK : PBM_WHITE;
--bitsperitem;
++bitshift;
return b;
}
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