161 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			161 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* $Id: tif_next.c,v 1.13 2010-03-10 18:56:48 bfriesen 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);	   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; occ > 0; occ -= scanline, row += scanline) {
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        n = *bp++, 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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            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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            uint32 imagewidth = tif->tif_dir.td_imagewidth;
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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)
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                    SETPIXEL(op, grey);
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                if (npixels >= imagewidth)
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                    break;
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                if (cc == 0)
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                    goto bad;
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                n = *bp++, 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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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_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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 */
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