/*
    This file is part of DITABIS, 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 "ditabis.h"
#include "entry.h" // must come after Photoshop includes

#include "str.h"
#include "ui.h"

long DoPrepare(long);

MACPASCAL void PluginMain(short selector,FormatRecordPtr pb,long *data,short *result);

DLLEXPORT
MACPASCAL void PluginMain(short selector,FormatRecordPtr pb,long *data,short *result){
	OSErr e = noErr;
	extern long ypixel,xpixel,byteperpixel;
	
	EnterCodeResource();
	
	/* Perform the requested operation */
		
	switch (selector){
	case formatSelectorAbout: 
		DoAbout((AboutRecordPtr)pb);
		break;

	case formatSelectorEstimatePrepare:
//	case formatSelectorWritePrepare:
	case formatSelectorReadPrepare:
		pb->maxData = DoPrepare(pb->maxData);
		break;

	case formatSelectorReadStart:    e = read_start(pb,data); break;
	case formatSelectorReadContinue: e = read_continue(pb,data); break;
	case formatSelectorReadFinish:   e = read_finish(pb,data); break;
/*
	case formatSelectorOptionsPrepare:
		pb->maxData = 0; // no buffers are allocated in Options 
		break;
	case formatSelectorOptionsStart:
		pb->data = 0;
	case formatSelectorOptionsContinue:
	case formatSelectorOptionsFinish:
		break;

	case formatSelectorEstimateStart:    e = estimate_start(pb,data); break;
	case formatSelectorEstimateContinue: e = estimate_continue(pb,data); break;
	case formatSelectorEstimateFinish:   e = estimate_finish(pb,data); break;

	case formatSelectorWriteStart:    e = write_start(pb,data); break;
	case formatSelectorWriteContinue: e = write_continue(pb,data); break;
	case formatSelectorWriteFinish:   e = write_finish(pb,data); break;
*/
	case formatSelectorFilterFile: 
		readheader((FILEREF)pb->dataFork,false);
		e = xpixel && ypixel && byteperpixel ? noErr : formatCannotRead;
		break;

	default: 
		e = formatBadParameters;
	}

	*result = e;
	
	ExitCodeResource();
}

long DoPrepare(long maxData){ // estimate the largest total of memory allocations we might need
	enum{ 
		MAX_MEM = (1L<<20) /* 1 megabyte */
	};

	return lesser(maxData / 2,MAX_MEM); // take half of available
}

long lesser(long a,long b){
	return a < b ? a : b;
}