pgmlO.c

/*
 * pgmlO.c
 *
 *  Created on: Dec 20, 2011
 *      Author: jamie
 */

#include "pgmIO.h"
FILE *_INFP = NULL; 
FILE *_OUTFP = NULL; 
///////////////////////////////////////////////////////////////////////////////////////////// 
//
// Line-wise pgm input routines: open file, read a line, close the file 
//
/////////////////////////////////////////////////////////////////////////////////////////////
int _openinpgm(char fname[], int width, int height) 
{ 
	char str[ 64 ];
    int inwidth, inheight; 
    _INFP = fopen( fname, "rb" );
	if( _INFP == NULL )
	{
		printf( "Could not open %s.\n", fname );
		return -1;
	}
	//Strip off header
    fgets( str, 64, _INFP ); //Version: P5
    fgets( str, 64, _INFP ); //width and height
    sscanf( str, "%d%d", &inwidth, &inheight ); 
    if( inwidth != width || inheight != height ) 
    { 
		printf( "Input image size(%dx%d) does not = %dx%d or trouble reading header\n", inwidth,
		inheight, width, height );
		return -1;
    } 
    fgets( str, 64, _INFP ); //bit depth, must be 255
    return 0;
} 

int _readinline(unsigned char line[], int width) 
{ 
	int nb;
	if( _INFP == NULL )
	{
		return -1;
	}
	nb = fread( line, 1, width, _INFP );
	if( nb != width )
	{
		//printf( "Error reading line, nb = %d\n", nb );
		//Error or end of file
		return -1;
	}
	return 0;
} 
int _closeinpgm() 
{ 
	int ret = fclose( _INFP );
	if( ret == 0 )
	{
		_INFP = NULL;
	}
	else
	{
		printf( "Error closing file _INFP.\n" );
	}
	return ret; //return zero for succes and EOF for fail
}

/////////////////////////////////////////////////////////////////////////////////////////////
//
// Line-wise pgm output routines: open file, read a line, close the file 
//
/////////////////////////////////////////////////////////////////////////////////////////////
int _openoutpgm(char fname[], int width, int height) 
{ 
	char hdr[ 64 ];
	_OUTFP = fopen( fname, "wb" );
	if( _OUTFP == NULL )
	{
		printf( "Could not open %s.\n", fname );
		return -1;
	}
	sprintf( hdr, "P5\n%d %d\n255\n", width, height );
	fprintf( _OUTFP, "%s", hdr );
	return 0;
} 

int _writeoutline(unsigned char line[], int width) 
{ 
	int nb;
	if( _OUTFP == NULL )
	{
		return -1;
	}
	nb = fwrite( line, 1, width, _OUTFP );
	if( nb != width )
	{
		//printf( "Error writing line, nb = %d\n", nb );
		//Error or end of file
		return -1;
	}
	return 0;
} 

int _closeoutpgm() 
{ 
	int ret = fclose( _OUTFP );
	if( ret == 0 )
	{
		_OUTFP = NULL;
	}
	else
	{
		printf( "Error closing file _OUTFP.\n" );
	}
	return ret; //return zero for succes and EOF for fail
}

/////////////////////////////////////////////////////////////////////////////////////////////
//
// standard pgm input and output routines 
//
// Input is a referenced array of unsigned chars of width and height and a
// referenced char array of the system path to destination, e.g.
// "/home/user/xmos/project/" on Linux or "C:\\user\\xmos\\project\\" on Windows 
// 
/////////////////////////////////////////////////////////////////////////////////////////////
int _writepgm(unsigned char x[], int height, int width, char fname[]) 
{ 
	FILE *fp;
	int hlen;
	char hdr[ 64 ];
	sprintf( hdr, "P5\n%d %d\n255\n", width, height );
	hlen = strlen( hdr );
	printf( "In writepgm function, writing: %s\n", fname );
	fp = fopen( fname, "wb" );
	if( fp == NULL)
	{
		printf( "Could not open %s for writing.\n", fname );
		return -1;
	}
	fprintf( fp, "%s", hdr );
	fwrite( x, width * height, 1, fp );
	fclose( fp );
	return 0;
} 

int _readpgm(unsigned char x[], int height, int width, char fname[])
{ 
    FILE *fp; 
    unsigned int inwidth, inheight;
	char str[ 64 ];
	printf( "In readpgm function, reading: %s\n", fname );
	fp = fopen( fname, "rb" );
	if( fp == NULL)
	{
		printf( "Could not open %s for reading.\n", fname );
		return -1;
	}
	fgets( str, 64, fp ); //Version: P5
	fgets( str, 64, fp ); //width and height
	sscanf( str, "%d%d", &inwidth, &inheight );
	fgets( str, 64, fp ); //bit depth, must be 255
	if( inwidth != width || inheight != height )
	{
		printf( "Input image size(%dx%d) does not = %dx%d or trouble reading header\n", inwidth,
		inheight, width, height );
		return -1;
	}
	fread( x, inwidth * inheight, 1, fp );
	fclose( fp );
	return 0;
}