/* Panorama_Tools	-	Generate, Edit and Convert Panoramic Images
   Copyright (C) 1998,1999 - Helmut Dersch  der@fh-furtwangen.de
   
   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; either version 2, or (at your option)
   any later version.

   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; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/*------------------------------------------------------------*/

// Functions to read and write ppm format


#include "filter.h"


static int readPPMFileHeader(file_spec src, Image *im);


// image is allocated, but not image data

int readPPM(Image *im, fullPath *sfile)
{
	file_spec	src;
	long count;
	
	if( myopen( sfile, read_bin, src ) )
	{	
		PrintError("Error Opening Image File");
		return -1;
	}
	

	if( readPPMFileHeader(src, im) != 0 )
	{
		PrintError("Error Reading File Header");
		myclose( src );
		return -1;
	}

	im->bitsPerPixel	= 24;	
	im->bytesPerLine 	= im->width * 3;
	im->dataSize		= im->bytesPerLine * im->height;
	
	im->data			= (unsigned char**) mymalloc( im->width * im->height * 4 );
	if ( im->data == NULL )
	{
		PrintError("Not enough memory");
		myclose( src );
		return -1;
	}
	
	count = 	im->width * im->height * 3;
	
	myread(src,count,*(im->data));
	
	if( count != im->width * im->height * 3 )
	{
		PrintError("Error Reading Image Data");
		myclose( src );
		return -1;
	}

	myclose( src );
	ThreeToFourBPP( im );
	return 0;
}
	

static int readPPMFileHeader(file_spec src, Image *im)
{
	int 			i;
	char 			smallBuf[32], c;
	long 			count = 1;
	
	/* read the file header (including height and width) */

	im->height = -1;
	while(im->height == -1)
	{
		myread(src,count,&c); 
		if( count != 1 ) return 1;
		switch(c)
		{
			case '#':
				/* comment line -- skip it */
				while(c != 0x0A	&& c != 0x0D && count == 1)
					myread(src,count,&c); 
				break;
			case ' ': case '\012': case '\t': case '\015':
				/* random whitespace... just ignore it. */
				break;
			case 'P':
				/* magic number */
				myread(src,count,&c); 
				if(c != '6' )
				{
					PrintError("Bad magic number in input file");
					return(-1);
				}
				/* there should be one whitespace character */
				break;
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				/* read width */
				for(i=0;isdigit(c) && (i+1 < sizeof(smallBuf));i++)
				{
					smallBuf[i] = c;
					myread(src,count,&c); 
					if( count != 1 ) return  -1;
				}
				if(!isspace(c))
				{
					PrintError("Bad input file format");
					return -1;
				}
				smallBuf[i] = 0;
				im->width = atoi(smallBuf);
				/* read height */
				myread(src,count,&c); 
				if( count != 1 ) return  -1;
				for(i=0;isdigit(c) && (i+1 < sizeof(smallBuf));i++)
				{
					smallBuf[i] = c;
					myread(src,count,&c); 
					if( count != 1 ) return  -1;
				}
				if(!isspace(c))
				{
					PrintError("Bad input file format");
					return -1;
				}
				smallBuf[i] = 0;
				im->height = atoi(smallBuf);
				/* read numColors */
				myread(src,count,&c); 
				if( count != 1 ) return  -1;
				for(i=0;isdigit(c) && (i+1 < sizeof(smallBuf));i++)
				{
					smallBuf[i] = c;
					myread(src,count,&c); 
					if( count != 1 ) return  -1;
				}
				if(!isspace(c))
				{
					PrintError("Bad input file format");
					return -1;
				}
				smallBuf[i] = 0;
				if(atoi(smallBuf) != 255)
					PrintError("Warning: Wrong Colordepth!");
				break;
			default:
					PrintError("Bad input file format");
					return(-1);
				break;
		}
	}
			
	/* the header has been taken care of.  The rest of the file is just image data. */	
	return(0);
}



int writePPM( Image *im, fullPath *sfile )
{
	char header[30];
	long count;
	file_spec	fnum;
	int y, cy, cpy;
	unsigned char* data;



	if(  myopen( sfile, write_bin, fnum )   )
	{	
		PrintError("Error Writing Image File");
		return -1;
	}

	if( im->bitsPerPixel == 32 )
		FourToThreeBPP	( im );
		
	if( im->bytesPerLine != im->width * 3 ) 	// Eliminate Pad bytes
	{
		data = *(im->data);
		for(y=0; y<im->height; y++)
		{
			cy = im->height * im->bytesPerLine;
			cpy = im->height * im->width * 3;

			memcpy( data+cpy, data+cy, im->width * 3);
		}
		im->bytesPerLine = im->width * 3;
		im->dataSize = im->height * im->bytesPerLine;
	}
					

	sprintf( header, "P6\n%ld %ld\n%ld\n", im->width, im->height, 255L);

	count = strlen( header );
	mywrite( fnum, count, header );
	
	if( count != strlen( header ))
	{
		PrintError("Error writing file header");
		return -1;
	}
	
	count = im->dataSize;
	mywrite( fnum, count, *(im->data) );
	
	if( count != im->dataSize )
	{
		PrintError("Error writing image data");
		return -1;
	}
	
	myclose( fnum );
	return 0;
}

int makeTempPath( fullPath *path ){
	file_spec fnum;
	char *dir;
	static int try = 0;
	int i;
	char fname[24];


	dir = strrchr( path->name, '/' );
	if( dir == NULL ){
		dir = path->name;
	}else{
		dir++;
	}

	
#define MAX_TEMP_TRY	1000
	
	try++;
	
	for(i=0; i < MAX_TEMP_TRY; try++,i++){
		sprintf( fname, "_PTStitcher_tmp_%d", try );
		if( strlen( fname ) + 2 < sizeof(path->name) - (strlen(path->name)-strlen(dir)) ){
			sprintf( dir, "%s", fname );
			if( myopen( path, read_bin, fnum ))
				break;
			myclose( fnum );
		}else{
			PrintError("Path too long");
			return -1;
		}
	}
	if( try < MAX_TEMP_TRY )
		return 0;
	else
		return -1;
	
}


int readImage( Image *im, fullPath *sfile )
{
	char *ext,extension[4];
	int i;
	
	
	ext = strrchr( sfile->name, '.' );
	if( ext == NULL || strlen(ext) != 4 )
	{
		PrintError("Unsupported File Format: Must be JPEG, TIF or PPM");
		return -1;
	}
	ext++;
	strcpy( extension, ext );
	for(i=0; i<3; i++)
		extension[i] = tolower(extension[i]);

	
	if( strcmp( extension, "ppm" ) == 0 )
		return readPPM(  im, sfile );
	else if( strcmp( extension, "jpg" ) == 0 )
		return readJPEG(im, sfile );
	else if( strcmp( extension, "tif" ) == 0 )
		return readTIFF(im, sfile );
	else{
		PrintError("Unsupported File Format: Must be JPEG, TIF or PPM");
		return -1;
	}
}
		

int writeImage( Image *im, fullPath *sfile ){
	return writePPM( im, sfile );
}


