Blame libtiff/tif_next.c

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/* $Id: tif_next.c,v 1.19 2016-09-04 21:32:56 erouault Exp $ */
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/*
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 * Copyright (c) 1988-1997 Sam Leffler
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 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
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 *
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 * Permission to use, copy, modify, distribute, and sell this software and 
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 * its documentation for any purpose is hereby granted without fee, provided
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 * that (i) the above copyright notices and this permission notice appear in
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 * all copies of the software and related documentation, and (ii) the names of
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 * Sam Leffler and Silicon Graphics may not be used in any advertising or
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 * publicity relating to the software without the specific, prior written
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 * permission of Sam Leffler and Silicon Graphics.
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 * 
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 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
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 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
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 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
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 * 
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 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
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 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
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 * OF THIS SOFTWARE.
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 */
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#include "tiffiop.h"
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#ifdef NEXT_SUPPORT
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/*
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 * TIFF Library.
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 *
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 * NeXT 2-bit Grey Scale Compression Algorithm Support
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 */
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#define SETPIXEL(op, v) {			\
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	switch (npixels++ & 3) {		\
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	case 0:	op[0]  = (unsigned char) ((v) << 6); break;	\
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	case 1:	op[0] |= (v) << 4; break;	\
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	case 2:	op[0] |= (v) << 2; break;	\
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	case 3:	*op++ |= (v);	   op_offset++; break;	\
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	}					\
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}
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#define LITERALROW	0x00
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#define LITERALSPAN	0x40
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#define WHITE   	((1<<2)-1)
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static int
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NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
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{
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	static const char module[] = "NeXTDecode";
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	unsigned char *bp, *op;
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	tmsize_t cc;
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	uint8* row;
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	tmsize_t scanline, n;
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	(void) s;
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	/*
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	 * Each scanline is assumed to start off as all
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	 * white (we assume a PhotometricInterpretation
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	 * of ``min-is-black'').
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	 */
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	for (op = (unsigned char*) buf, cc = occ; cc-- > 0;)
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		*op++ = 0xff;
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	bp = (unsigned char *)tif->tif_rawcp;
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	cc = tif->tif_rawcc;
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	scanline = tif->tif_scanlinesize;
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	if (occ % scanline)
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	{
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		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
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		return (0);
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	}
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	for (row = buf; cc > 0 && occ > 0; occ -= scanline, row += scanline) {
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		n = *bp++;
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		cc--;
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		switch (n) {
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		case LITERALROW:
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			/*
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			 * The entire scanline is given as literal values.
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			 */
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			if (cc < scanline)
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				goto bad;
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			_TIFFmemcpy(row, bp, scanline);
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			bp += scanline;
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			cc -= scanline;
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			break;
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		case LITERALSPAN: {
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			tmsize_t off;
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			/*
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			 * The scanline has a literal span that begins at some
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			 * offset.
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			 */
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			if( cc < 4 )
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				goto bad;
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			off = (bp[0] * 256) + bp[1];
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			n = (bp[2] * 256) + bp[3];
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			if (cc < 4+n || off+n > scanline)
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				goto bad;
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			_TIFFmemcpy(row+off, bp+4, n);
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			bp += 4+n;
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			cc -= 4+n;
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			break;
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		}
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		default: {
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			uint32 npixels = 0, grey;
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			tmsize_t op_offset = 0;
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			uint32 imagewidth = tif->tif_dir.td_imagewidth;
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            if( isTiled(tif) )
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                imagewidth = tif->tif_dir.td_tilewidth;
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			/*
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			 * The scanline is composed of a sequence of constant
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			 * color ``runs''.  We shift into ``run mode'' and
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			 * interpret bytes as codes of the form
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			 * <color><npixels> until we've filled the scanline.
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			 */
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			op = row;
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			for (;;) {
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				grey = (uint32)((n>>6) & 0x3);
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				n &= 0x3f;
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				/*
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				 * Ensure the run does not exceed the scanline
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				 * bounds, potentially resulting in a security
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				 * issue.
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				 */
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				while (n-- > 0 && npixels < imagewidth && op_offset < scanline)
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					SETPIXEL(op, grey);
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				if (npixels >= imagewidth)
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					break;
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                if (op_offset >= scanline ) {
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                    TIFFErrorExt(tif->tif_clientdata, module, "Invalid data for scanline %ld",
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                        (long) tif->tif_row);
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                    return (0);
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                }
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				if (cc == 0)
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					goto bad;
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				n = *bp++;
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				cc--;
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			}
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			break;
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		}
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		}
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	}
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	tif->tif_rawcp = (uint8*) bp;
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	tif->tif_rawcc = cc;
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	return (1);
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bad:
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	TIFFErrorExt(tif->tif_clientdata, module, "Not enough data for scanline %ld",
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	    (long) tif->tif_row);
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	return (0);
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}
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static int
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NeXTPreDecode(TIFF* tif, uint16 s)
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{
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	static const char module[] = "NeXTPreDecode";
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	TIFFDirectory *td = &tif->tif_dir;
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	(void)s;
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	if( td->td_bitspersample != 2 )
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	{
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		TIFFErrorExt(tif->tif_clientdata, module, "Unsupported BitsPerSample = %d",
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					 td->td_bitspersample);
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		return (0);
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	}
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	return (1);
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}
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int
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TIFFInitNeXT(TIFF* tif, int scheme)
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{
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	(void) scheme;
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	tif->tif_predecode = NeXTPreDecode;  
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	tif->tif_decoderow = NeXTDecode;  
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	tif->tif_decodestrip = NeXTDecode;  
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	tif->tif_decodetile = NeXTDecode;
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	return (1);
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}
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#endif /* NEXT_SUPPORT */
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/* vim: set ts=8 sts=8 sw=8 noet: */
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/*
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 * Local Variables:
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 * mode: c
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 * c-basic-offset: 8
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 * fill-column: 78
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 * End:
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 */