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/* imgtoppm.c - read an Img-whatnot file and produce a portable pixmap
**
** Based on a simple conversion program posted to comp.graphics by Ed Falk.
**
** Copyright (C) 1989 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 <string.h>
#include "ppm.h"
int
main(int argc, char ** argv) {
FILE* ifp;
pixel* pixelrow;
pixel colormap[256];
register pixel* pP;
unsigned int cols;
unsigned int rows;
int argn, row, i;
int col;
pixval maxval;
unsigned int cmaplen;
int len, gotAT, gotCM, gotPD;
unsigned char buf[4096];
unsigned char* bP;
ppm_init( &argc, argv );
argn = 1;
if ( argn < argc )
{
ifp = pm_openr( argv[argn] );
argn++;
}
else
ifp = stdin;
if ( argn != argc )
pm_usage( "[imgfile]" );
/* Get signature. */
fread( buf, 8, 1, ifp );
buf[8] = '\0';
/* Get entries. */
gotAT = 0;
gotCM = 0;
gotPD = 0;
while ( fread( buf, 2, 1, ifp ) == 1 )
{
if ( strncmp( (char*) buf, "AT", 2 ) == 0 )
{
if ( fread( buf, 8, 1, ifp ) != 1 )
pm_error( "bad attributes header" );
buf[8] = '\0';
len = atoi( (char*) buf );
if ( fread( buf, len, 1, ifp ) != 1 )
pm_error( "bad attributes buf" );
buf[len] = '\0';
sscanf( (char*) buf, "%4u%4u%4u", &cols, &rows, &cmaplen );
maxval = 255;
gotAT = 1;
}
else if ( strncmp( (char*) buf, "CM", 2 ) == 0 )
{
if ( ! gotAT )
pm_error( "missing attributes header" );
if ( fread( buf, 8, 1, ifp ) != 1 )
pm_error( "bad colormap header" );
buf[8] = '\0';
len = atoi((char*) buf );
if ( fread( buf, len, 1, ifp ) != 1 )
pm_error( "bad colormap buf" );
if ( cmaplen * 3 != len )
{
pm_message(
"cmaplen (%d) and colormap buf length (%d) do not match",
cmaplen, len );
if ( cmaplen * 3 < len )
len = cmaplen * 3;
else if ( cmaplen * 3 > len )
cmaplen = len / 3;
}
for ( i = 0; i < len; i += 3 )
PPM_ASSIGN( colormap[i / 3], buf[i], buf[i + 1], buf[i + 2] );
gotCM = 1;
}
else if ( strncmp( (char*) buf, "PD", 2 ) == 0 )
{
if ( fread( buf, 8, 1, ifp ) != 1 )
pm_error( "bad pixel data header" );
buf[8] = '\0';
len = atoi((char*) buf );
if ( len != cols * rows )
pm_message(
"pixel data length (%d) does not match image size (%d)",
len, cols * rows );
ppm_writeppminit( stdout, cols, rows, maxval, 0 );
pixelrow = ppm_allocrow( cols );
for ( row = 0; row < rows; row++ )
{
if ( fread( buf, 1, cols, ifp ) != cols )
pm_error( "EOF / read error" );
for ( col = 0, pP = pixelrow, bP = buf;
col < cols; col++, pP++, bP++ )
{
if ( gotCM )
*pP = colormap[*bP];
else
PPM_ASSIGN( *pP, *bP, *bP, *bP );
}
ppm_writeppmrow( stdout, pixelrow, cols, maxval, 0 );
}
gotPD = 1;
}
}
if ( ! gotPD )
pm_error( "missing pixel data header" );
pm_close( ifp );
/* If the program failed, it previously aborted with nonzero completion
code, via various function calls.
*/
return 0;
}
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