/*
    This file is part of MacPaint Format, a File Format plugin for Adobe Photoshop
    Copyright (C) 2003-6 Toby Thain, toby@telegraphics.com.au

    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 of the License, 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

//#include <stdio.h>

#include <string.h>
#include <stdlib.h>

#include "macpaint.h"
#include "file_io.h"
#include "bufio.h"

char *indata;

/*
See:
	http://developer.apple.com/technotes/tn/tn1023.html (Understanding PackBits)
	http://developer.apple.com/technotes/pt/pt_24.html (MacPaint Document Format)
*/

OSErr read_start(FormatRecordPtr pb,long *data){
	OSErr e = formatCannotRead;
	int i,j,len,val;
	char *q;

	if( (indata = malloc((long)PNTG_ROWS*PNTG_ROWBYTES)) ){
	
		pb->imageMode = plugInModeBitmap;
		pb->depth = 1;
		pb->planes = 1;
		pb->imageHRes = pb->imageVRes = 72L<<16;
		
		pb->theRect.left = pb->theRect.top = 0;
		pb->theRect.right = pb->imageSize.h = PNTG_COLS;
		pb->theRect.bottom = pb->imageSize.v = PNTG_ROWS;
		pb->loPlane = pb->hiPlane = 0;
		
		pb->colBytes = 1;
		pb->rowBytes = PNTG_ROWBYTES;
		pb->data = indata;
		
//		if( !(e = read4B(pb->dataFork,&version)) ){
//			if(version == 2){
				if(!(e = SetFPos((FILEREF)pb->dataFork,fsFromStart,PNTG_HEADERSIZE))){
					/* each row is PackBits compressed.  */
					for(j = PNTG_ROWS,q = indata ; j-- ; ){
//sprintf(s,"j = %d",j);dbg(s);
						for(i = 0 ; i < PNTG_ROWBYTES ; ){
							len = bufgetc((FILEREF)pb->dataFork);
							if(len == EOF){
								//dbg("EOF getting flag byte");
								break; // EOF getting flag byte
							}else if(len == 128)
								; /*ignore this flag value*/
							else{
								if(len > 128){
									len = 1+256-len;
									if((val = bufgetc((FILEREF)pb->dataFork)) == EOF){
										//dbg("EOF getting repeat value");
										break; // EOF getting repeat value
									}else if((i+len) <= PNTG_ROWBYTES)
										memset(q,val,len);
									else{ 
										//dbg("unpacked data would overflow row(1)");
										break; /* unpacked data would overflow row! */
									}
								}else{
									++len;
									if((i+len) <= PNTG_ROWBYTES){
										if( (e = bufgetbytes((FILEREF)pb->dataFork,len,q)) )
											break;
									}else{
										//dbg("unpacked data would overflow row(2)");
										break; /* unpacked data would overflow row! */
									}
								}
								q += len;
								i += len;
							}
//sprintf(s,"end run; %d bytes unpacked",i);dbg(s);
						}
					}
					if(!j)
						e = noErr; /* we made it! */
				}//else dbg("can't SetFPos at end of header");
//			}else e = formatCannotRead;
//		}

		if(e) free(indata);
	}else e = memFullErr;
	
	return e;
}

OSErr read_continue(FormatRecordPtr pb,long *data){
	pb->data = 0;
	return noErr;
}

OSErr read_finish(FormatRecordPtr pb,long *data){
	free(indata);
	return noErr;
}