/*
    This file is part of SGI Format, a File Format plugin for Adobe Photoshop
    Copyright (C) 2003-9 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 "sgiformat.h"

Boolean is_sgi(FILEREF r,struct sgi_header *h){
	return ! read_sgi_header(r,h) /* && h->magic == SGI_MAGIC */ ;
}

OSErr read_sgi_header(FILEREF f,struct sgi_header *h){
	FILECOUNT count = SGI_IMAGENAME_SIZE;
	FILEPOS pos;
	OSErr e;

	if( !(e = GETFPOS(f,&pos)) && !(e = read2B(f,(short*)&h->magic)) ){
		if( h->magic == SGI_MAGIC ){		/*  iris image file magic number */
			/* header is BigEndian (normal) */
			   (e = read1 (f,(unsigned char*)&h->storage))		/*  storage format */
			|| (e = read1 (f,(unsigned char*)&h->bpc))			/*  number of bytes per pixel channel  */
			|| (e = read2B(f,(short*)&h->dimension))	/*  number of dimensions */
			|| (e = read2B(f,(short*)&h->xsize))		/*  x size in pixels  */
			|| (e = read2B(f,(short*)&h->ysize))		/*  y size in pixels  */
			|| (e = read2B(f,(short*)&h->zsize))		/*  number of channels */
			|| (e = read4B(f,&h->pixmin))		/*  minimum pixel value */
			|| (e = read4B(f,&h->pixmax))		/*  maximum pixel value */
			|| (e = read1 (f,(unsigned char*)&h->dummy))		/*  ignored */
			|| (e = FSREAD(f,&count,&h->imagename))
			|| (e = read4B(f,&h->colormap));		/*  colormap id */
		}else if( h->magic == SGI_MAGIC_LITTLEENDIAN ){
			/* header is LittleEndian (unusual) */
			   (e = read1 (f,(unsigned char*)&h->storage))		/*  storage format */
			|| (e = read1 (f,(unsigned char*)&h->bpc))			/*  number of bytes per pixel channel  */
			|| (e = read2L(f,(short*)&h->dimension))	/*  number of dimensions */
			|| (e = read2L(f,(short*)&h->xsize))		/*  x size in pixels  */
			|| (e = read2L(f,(short*)&h->ysize))		/*  y size in pixels  */
			|| (e = read2L(f,(short*)&h->zsize))		/*  number of channels */
			|| (e = read4L(f,&h->pixmin))		/*  minimum pixel value */
			|| (e = read4L(f,&h->pixmax))		/*  maximum pixel value */
			|| (e = read1 (f,(unsigned char*)&h->dummy))		/*  ignored */
			|| (e = FSREAD(f,&count,&h->imagename))
			|| (e = read4L(f,&h->colormap));		/*  colormap id */
		}else e = formatCannotRead;

		if(!e)
			e = SETFPOS(f,fsFromStart,pos+SGI_HEADER_SIZE);
	}
	return e;
}

OSErr write_sgi_header(FILEREF f,struct sgi_header *h){
	FILECOUNT count = SGI_IMAGENAME_SIZE;
	FILEPOS pos;
	OSErr e;

	   (e = GETFPOS(f,&pos))
	|| (e = write2B(f,h->magic))		/*  iris image file magic number */
	|| (e = write1 (f,h->storage))		/*  storage format */
	|| (e = write1 (f,h->bpc))			/*  number of bytes per pixel channel  */
	|| (e = write2B(f,h->dimension))	/*  number of dimensions */
	|| (e = write2B(f,h->xsize))		/*  x size in pixels  */
	|| (e = write2B(f,h->ysize))		/*  y size in pixels  */
	|| (e = write2B(f,h->zsize))		/*  number of channels */
	|| (e = write4B(f,h->pixmin))		/*  minimum pixel value */
	|| (e = write4B(f,h->pixmax))		/*  maximum pixel value */
	|| (e = write1 (f,h->dummy))		/*  ignored */
	|| (e = FSWRITE(f,&count,&h->imagename))
	|| (e = write4B(f,h->colormap))		/*  colormap id */
	|| (e = SETFPOS(f,fsFromStart,pos+SGI_HEADER_SIZE));
	return e;
}