/* $Id: tif_next.c,v 1.8.2.1 2010-06-08 18:50:42 bfriesen Exp $ */

/*

 * Copyright (c) 1988-1997 Sam Leffler

 * Copyright (c) 1991-1997 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.

 */

#include "tiffiop.h"

#ifdef NEXT_SUPPORT

/*

 * TIFF Library.

 *

 * NeXT 2-bit Grey Scale Compression Algorithm Support

 */

#define SETPIXEL(op, v) {			\

	switch (npixels++ & 3) {		\

	case 0:	op[0]  = (unsigned char) ((v) << 6); break;	\

	case 1:	op[0] |= (v) << 4; break;	\

	case 2:	op[0] |= (v) << 2; break;	\

	case 3:	*op++ |= (v);	   break;	\

	}					\

}

#define LITERALROW	0x00

#define LITERALSPAN	0x40

#define WHITE   	((1<<2)-1)

static int

NeXTDecode(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)

{

	unsigned char *bp, *op;

	tsize_t cc;

	tidata_t row;

	tsize_t scanline, n;

	(void) s;

	/*

	 * Each scanline is assumed to start off as all

	 * white (we assume a PhotometricInterpretation

	 * of ``min-is-black'').

	 */

	for (op = buf, cc = occ; cc-- > 0;)

		*op++ = 0xff;

	bp = (unsigned char *)tif->tif_rawcp;

	cc = tif->tif_rawcc;

	scanline = tif->tif_scanlinesize;

	for (row = buf; occ > 0; occ -= scanline, row += scanline) {

		n = *bp++, cc--;

		switch (n) {

		case LITERALROW:

			/*

			 * The entire scanline is given as literal values.

			 */

			if (cc < scanline)

				goto bad;

			_TIFFmemcpy(row, bp, scanline);

			bp += scanline;

			cc -= scanline;

			break;

		case LITERALSPAN: {

			tsize_t off;

			/*

			 * The scanline has a literal span that begins at some

			 * offset.

			 */

			off = (bp[0] * 256) + bp[1];

			n = (bp[2] * 256) + bp[3];

			if (cc < 4+n || off+n > scanline)

				goto bad;

			_TIFFmemcpy(row+off, bp+4, n);

			bp += 4+n;

			cc -= 4+n;

			break;

		}

		default: {

			uint32 npixels = 0, grey;

			uint32 imagewidth = tif->tif_dir.td_imagewidth;

			/*

			 * The scanline is composed of a sequence of constant

			 * color ``runs''.  We shift into ``run mode'' and

			 * interpret bytes as codes of the form

			 * <color><npixels> until we've filled the scanline.

			 */

			op = row;

			for (;;) {

				grey = (n>>6) & 0x3;

				n &= 0x3f;

				/*

				 * Ensure the run does not exceed the scanline

				 * bounds, potentially resulting in a security

				 * issue.

				 */

				while (n-- > 0 && npixels < imagewidth)

					SETPIXEL(op, grey);

				if (npixels >= imagewidth)

					break;

				if (cc == 0)

					goto bad;

				n = *bp++, cc--;

			}

			break;

		}

		}

	}

	tif->tif_rawcp = (tidata_t) bp;

	tif->tif_rawcc = cc;

	return (1);

bad:

	TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "NeXTDecode: Not enough data for scanline %ld",

	    (long) tif->tif_row);

	return (0);

}

int

TIFFInitNeXT(TIFF* tif, int scheme)

{

	(void) scheme;

	tif->tif_decoderow = NeXTDecode;

	tif->tif_decodestrip = NeXTDecode;

	tif->tif_decodetile = NeXTDecode;

	return (1);

}

#endif /* NEXT_SUPPORT */

/* vim: set ts=8 sts=8 sw=8 noet: */

/*

 * Local Variables:

 * mode: c

 * c-basic-offset: 8

 * fill-column: 78

 * End:

 */