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/*
* 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); op_offset++; break; \
} \
}
#define LITERALROW 0x00
#define LITERALSPAN 0x40
#define WHITE ((1<<2)-1)
static int
NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
{
static const char module[] = "NeXTDecode";
unsigned char *bp, *op;
tmsize_t cc;
uint8* row;
tmsize_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 = (unsigned char*) buf, cc = occ; cc-- > 0;)
*op++ = 0xff;
bp = (unsigned char *)tif->tif_rawcp;
cc = tif->tif_rawcc;
scanline = tif->tif_scanlinesize;
if (occ % scanline)
{
TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
return (0);
}
for (row = buf; cc > 0 && 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: {
tmsize_t off;
/*
* The scanline has a literal span that begins at some
* offset.
*/
if( cc < 4 )
goto bad;
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;
tmsize_t op_offset = 0;
uint32 imagewidth = tif->tif_dir.td_imagewidth;
if( isTiled(tif) )
imagewidth = tif->tif_dir.td_tilewidth;
/*
* 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 = (uint32)((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 && op_offset < scanline)
SETPIXEL(op, grey);
if (npixels >= imagewidth)
break;
if (op_offset >= scanline ) {
TIFFErrorExt(tif->tif_clientdata, module, "Invalid data for scanline %ld",
(long) tif->tif_row);
return (0);
}
if (cc == 0)
goto bad;
n = *bp++;
cc--;
}
break;
}
}
}
tif->tif_rawcp = (uint8*) bp;
tif->tif_rawcc = cc;
return (1);
bad:
TIFFErrorExt(tif->tif_clientdata, module, "Not enough data for scanline %ld",
(long) tif->tif_row);
return (0);
}
static int
NeXTPreDecode(TIFF* tif, uint16 s)
{
static const char module[] = "NeXTPreDecode";
TIFFDirectory *td = &tif->tif_dir;
(void)s;
if( td->td_bitspersample != 2 )
{
TIFFErrorExt(tif->tif_clientdata, module, "Unsupported BitsPerSample = %d",
td->td_bitspersample);
return (0);
}
return (1);
}
int
TIFFInitNeXT(TIFF* tif, int scheme)
{
(void) scheme;
tif->tif_predecode = NeXTPreDecode;
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:
*/
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