/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.1 (the "License").  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1988, 1989, 1990, 1991 Sam Leffler
 * Copyright (c) 1991 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

/*
 * TIFF Library.
 *
 * PackBits Compression Algorithm Support
 */
#import "bitmap.h"
#import "libsa.h"

typedef unsigned int u_int;
typedef unsigned char u_char;

int
PackBitsDecode(tif, op, occ, s)
	TIFF *tif;
	register u_char *op;
	register int occ;
	u_int s;
{
	register char *bp;
	register int n, b;
	register int cc;

	bp = tif->tif_rawcp; cc = tif->tif_rawcc;
	while (cc > 0 && occ > 0) {
		n = (int) *bp++; cc--;
		/*
		 * Watch out for compilers that
		 * don't sign extend chars...
		 */
		if (n >= 128)
			n -= 256;
		if (n < 0) {		/* replicate next byte -n+1 times */
			cc--;
			if (n == -128)	/* nop */
				continue;
			n = -n + 1;
			occ -= n;
			for (b = *bp++; n-- > 0;)
				*op++ = b;
		} else {		/* copy next n+1 bytes literally */
			bcopy(bp, op, ++n);
			op += n; occ -= n;
			bp += n; cc -= n;
		}
	}
	tif->tif_rawcp = bp;
	tif->tif_rawcc = cc;
	if (occ > 0) {
//		TIFFError(tif->tif_name,
//		    "PackBitsDecode: Not enough data for scanline %d",
//		    tif->tif_row);
//		reallyPrint("Not enough data\n");
		return (0);
	}
	/* check for buffer overruns? */
	return (1);
}