/* $Id: tif_next.c,v 1.13 2010-03-10 18:56:48 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); 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;

uint32 imagewidth = tif->tif_dir.td_imagewidth;

tmsize_t op_offset = 0;

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:

*/