src/tiff/libtiff/tif_thunder.c


/*
 * 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"
#include <assert.h>
#ifdef THUNDER_SUPPORT
/*
 * TIFF Library.
 *
 * ThunderScan 4-bit Compression Algorithm Support
 */

/*
 * ThunderScan uses an encoding scheme designed for
 * 4-bit pixel values.  Data is encoded in bytes, with
 * each byte split into a 2-bit code word and a 6-bit
 * data value.  The encoding gives raw data, runs of
 * pixels, or pixel values encoded as a delta from the
 * previous pixel value.  For the latter, either 2-bit
 * or 3-bit delta values are used, with the deltas packed
 * into a single byte.
 */
#define	THUNDER_DATA		0x3f	/* mask for 6-bit data */
#define	THUNDER_CODE		0xc0	/* mask for 2-bit code word */
/* code values */
#define	THUNDER_RUN		0x00	/* run of pixels w/ encoded count */
#define	THUNDER_2BITDELTAS	0x40	/* 3 pixels w/ encoded 2-bit deltas */
#define	    DELTA2_SKIP		2	/* skip code for 2-bit deltas */
#define	THUNDER_3BITDELTAS	0x80	/* 2 pixels w/ encoded 3-bit deltas */
#define	    DELTA3_SKIP		4	/* skip code for 3-bit deltas */
#define	THUNDER_RAW		0xc0	/* raw data encoded */

static const int twobitdeltas[4] = { 0, 1, 0, -1 };
static const int threebitdeltas[8] = { 0, 1, 2, 3, 0, -3, -2, -1 };

#define	SETPIXEL(op, v) {                     \
	lastpixel = (v) & 0xf;                \
        if ( npixels < maxpixels )         \
        {                                     \
	  if (npixels++ & 1)                  \
	    *op++ |= lastpixel;               \
	  else                                \
	    op[0] = (uint8) (lastpixel << 4); \
        }                                     \
}

static int
ThunderSetupDecode(TIFF* tif)
{
	static const char module[] = "ThunderSetupDecode";

        if( tif->tif_dir.td_bitspersample != 4 )
        {
                TIFFErrorExt(tif->tif_clientdata, module,
                             "Wrong bitspersample value (%d), Thunder decoder only supports 4bits per sample.",
                             (int) tif->tif_dir.td_bitspersample );
                return 0;
        }


	return (1);
}

static int
ThunderDecode(TIFF* tif, uint8* op, tmsize_t maxpixels)
{
	static const char module[] = "ThunderDecode";
	register unsigned char *bp;
	register tmsize_t cc;
	unsigned int lastpixel;
	tmsize_t npixels;

	bp = (unsigned char *)tif->tif_rawcp;
	cc = tif->tif_rawcc;
	lastpixel = 0;
	npixels = 0;
	while (cc > 0 && npixels < maxpixels) {
		int n, delta;

		n = *bp++, cc--;
		switch (n & THUNDER_CODE) {
		case THUNDER_RUN:		/* pixel run */
			/*
			 * Replicate the last pixel n times,
			 * where n is the lower-order 6 bits.
			 */
			if (npixels & 1) {
				op[0] |= lastpixel;
				lastpixel = *op++; npixels++; n--;
			} else
				lastpixel |= lastpixel << 4;
			npixels += n;
			if (npixels < maxpixels) {
				for (; n > 0; n -= 2)
					*op++ = (uint8) lastpixel;
			}
			if (n == -1)
				*--op &= 0xf0;
			lastpixel &= 0xf;
			break;
		case THUNDER_2BITDELTAS:	/* 2-bit deltas */
			if ((delta = ((n >> 4) & 3)) != DELTA2_SKIP)
				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
			if ((delta = ((n >> 2) & 3)) != DELTA2_SKIP)
				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
			if ((delta = (n & 3)) != DELTA2_SKIP)
				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
			break;
		case THUNDER_3BITDELTAS:	/* 3-bit deltas */
			if ((delta = ((n >> 3) & 7)) != DELTA3_SKIP)
				SETPIXEL(op, lastpixel + threebitdeltas[delta]);
			if ((delta = (n & 7)) != DELTA3_SKIP)
				SETPIXEL(op, lastpixel + threebitdeltas[delta]);
			break;
		case THUNDER_RAW:		/* raw data */
			SETPIXEL(op, n);
			break;
		}
	}
	tif->tif_rawcp = (uint8*) bp;
	tif->tif_rawcc = cc;
	if (npixels != maxpixels) {
#if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
		TIFFErrorExt(tif->tif_clientdata, module,
			     "%s data at scanline %lu (%I64u != %I64u)",
			     npixels < maxpixels ? "Not enough" : "Too much",
			     (unsigned long) tif->tif_row,
			     (unsigned __int64) npixels,
			     (unsigned __int64) maxpixels);
#else
		TIFFErrorExt(tif->tif_clientdata, module,
			     "%s data at scanline %lu (%llu != %llu)",
			     npixels < maxpixels ? "Not enough" : "Too much",
			     (unsigned long) tif->tif_row,
			     (unsigned long long) npixels,
			     (unsigned long long) maxpixels);
#endif
		return (0);
	}

        return (1);
}

static int
ThunderDecodeRow(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
{
	static const char module[] = "ThunderDecodeRow";
	uint8* row = buf;

	(void) s;
	if (occ % tif->tif_scanlinesize)
	{
		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
		return (0);
	}
	while (occ > 0) {
		if (!ThunderDecode(tif, row, tif->tif_dir.td_imagewidth))
			return (0);
		occ -= tif->tif_scanlinesize;
		row += tif->tif_scanlinesize;
	}
	return (1);
}

int
TIFFInitThunderScan(TIFF* tif, int scheme)
{
	(void) scheme;

        tif->tif_setupdecode = ThunderSetupDecode;
	tif->tif_decoderow = ThunderDecodeRow;
	tif->tif_decodestrip = ThunderDecodeRow;
	return (1);
}
#endif /* THUNDER_SUPPORT */

/* vim: set ts=8 sts=8 sw=8 noet: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 8
 * fill-column: 78
 * End:
 */
Commit	Line	Data
	1
	2	/*
	3	* Copyright (c) 1988-1997 Sam Leffler
	4	* Copyright (c) 1991-1997 Silicon Graphics, Inc.
	5	*
	6	* Permission to use, copy, modify, distribute, and sell this software and
	7	* its documentation for any purpose is hereby granted without fee, provided
	8	* that (i) the above copyright notices and this permission notice appear in
	9	* all copies of the software and related documentation, and (ii) the names of
	10	* Sam Leffler and Silicon Graphics may not be used in any advertising or
	11	* publicity relating to the software without the specific, prior written
	12	* permission of Sam Leffler and Silicon Graphics.
	13	*
	14	* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	15	* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	16	* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	17	*
	18	* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	19	* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	20	* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	21	* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	22	* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	23	* OF THIS SOFTWARE.
	24	*/
	25
	26	#include "tiffiop.h"
	27	#include <assert.h>
	28	#ifdef THUNDER_SUPPORT
	29	/*
	30	* TIFF Library.
	31	*
	32	* ThunderScan 4-bit Compression Algorithm Support
	33	*/
	34
	35	/*
	36	* ThunderScan uses an encoding scheme designed for
	37	* 4-bit pixel values. Data is encoded in bytes, with
	38	* each byte split into a 2-bit code word and a 6-bit
	39	* data value. The encoding gives raw data, runs of
	40	* pixels, or pixel values encoded as a delta from the
	41	* previous pixel value. For the latter, either 2-bit
	42	* or 3-bit delta values are used, with the deltas packed
	43	* into a single byte.
	44	*/
	45	#define THUNDER_DATA 0x3f /* mask for 6-bit data */
	46	#define THUNDER_CODE 0xc0 /* mask for 2-bit code word */
	47	/* code values */
	48	#define THUNDER_RUN 0x00 /* run of pixels w/ encoded count */
	49	#define THUNDER_2BITDELTAS 0x40 /* 3 pixels w/ encoded 2-bit deltas */
	50	#define DELTA2_SKIP 2 /* skip code for 2-bit deltas */
	51	#define THUNDER_3BITDELTAS 0x80 /* 2 pixels w/ encoded 3-bit deltas */
	52	#define DELTA3_SKIP 4 /* skip code for 3-bit deltas */
	53	#define THUNDER_RAW 0xc0 /* raw data encoded */
	54
	55	static const int twobitdeltas[4] = { 0, 1, 0, -1 };
	56	static const int threebitdeltas[8] = { 0, 1, 2, 3, 0, -3, -2, -1 };
	57
	58	#define SETPIXEL(op, v) { \
	59	lastpixel = (v) & 0xf; \
	60	if ( npixels < maxpixels ) \
	61	{ \
	62	if (npixels++ & 1) \
	63	*op++ \|= lastpixel; \
	64	else \
	65	op[0] = (uint8) (lastpixel << 4); \
	66	} \
	67	}
	68
	69	static int
	70	ThunderSetupDecode(TIFF* tif)
	71	{
	72	static const char module[] = "ThunderSetupDecode";
	73
	74	if( tif->tif_dir.td_bitspersample != 4 )
	75	{
	76	TIFFErrorExt(tif->tif_clientdata, module,
	77	"Wrong bitspersample value (%d), Thunder decoder only supports 4bits per sample.",
	78	(int) tif->tif_dir.td_bitspersample );
	79	return 0;
	80	}
	81
	82
	83	return (1);
	84	}
	85
	86	static int
	87	ThunderDecode(TIFF* tif, uint8* op, tmsize_t maxpixels)
	88	{
	89	static const char module[] = "ThunderDecode";
	90	register unsigned char *bp;
	91	register tmsize_t cc;
	92	unsigned int lastpixel;
	93	tmsize_t npixels;
	94
	95	bp = (unsigned char *)tif->tif_rawcp;
	96	cc = tif->tif_rawcc;
	97	lastpixel = 0;
	98	npixels = 0;
	99	while (cc > 0 && npixels < maxpixels) {
	100	int n, delta;
	101
	102	n = *bp++, cc--;
	103	switch (n & THUNDER_CODE) {
	104	case THUNDER_RUN: /* pixel run */
	105	/*
	106	* Replicate the last pixel n times,
	107	* where n is the lower-order 6 bits.
	108	*/
	109	if (npixels & 1) {
	110	op[0] \|= lastpixel;
	111	lastpixel = *op++; npixels++; n--;
	112	} else
	113	lastpixel \|= lastpixel << 4;
	114	npixels += n;
	115	if (npixels < maxpixels) {
	116	for (; n > 0; n -= 2)
	117	*op++ = (uint8) lastpixel;
	118	}
	119	if (n == -1)
	120	*--op &= 0xf0;
	121	lastpixel &= 0xf;
	122	break;
	123	case THUNDER_2BITDELTAS: /* 2-bit deltas */
	124	if ((delta = ((n >> 4) & 3)) != DELTA2_SKIP)
	125	SETPIXEL(op, lastpixel + twobitdeltas[delta]);
	126	if ((delta = ((n >> 2) & 3)) != DELTA2_SKIP)
	127	SETPIXEL(op, lastpixel + twobitdeltas[delta]);
	128	if ((delta = (n & 3)) != DELTA2_SKIP)
	129	SETPIXEL(op, lastpixel + twobitdeltas[delta]);
	130	break;
	131	case THUNDER_3BITDELTAS: /* 3-bit deltas */
	132	if ((delta = ((n >> 3) & 7)) != DELTA3_SKIP)
	133	SETPIXEL(op, lastpixel + threebitdeltas[delta]);
	134	if ((delta = (n & 7)) != DELTA3_SKIP)
	135	SETPIXEL(op, lastpixel + threebitdeltas[delta]);
	136	break;
	137	case THUNDER_RAW: /* raw data */
	138	SETPIXEL(op, n);
	139	break;
	140	}
	141	}
	142	tif->tif_rawcp = (uint8*) bp;
	143	tif->tif_rawcc = cc;
	144	if (npixels != maxpixels) {
	145	#if defined(__WIN32__) && (defined(_MSC_VER) \|\| defined(__MINGW32__))
	146	TIFFErrorExt(tif->tif_clientdata, module,
	147	"%s data at scanline %lu (%I64u != %I64u)",
	148	npixels < maxpixels ? "Not enough" : "Too much",
	149	(unsigned long) tif->tif_row,
	150	(unsigned __int64) npixels,
	151	(unsigned __int64) maxpixels);
	152	#else
	153	TIFFErrorExt(tif->tif_clientdata, module,
	154	"%s data at scanline %lu (%llu != %llu)",
	155	npixels < maxpixels ? "Not enough" : "Too much",
	156	(unsigned long) tif->tif_row,
	157	(unsigned long long) npixels,
	158	(unsigned long long) maxpixels);
	159	#endif
	160	return (0);
	161	}
	162
	163	return (1);
	164	}
	165
	166	static int
	167	ThunderDecodeRow(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
	168	{
	169	static const char module[] = "ThunderDecodeRow";
	170	uint8* row = buf;
	171
	172	(void) s;
	173	if (occ % tif->tif_scanlinesize)
	174	{
	175	TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
	176	return (0);
	177	}
	178	while (occ > 0) {
	179	if (!ThunderDecode(tif, row, tif->tif_dir.td_imagewidth))
	180	return (0);
	181	occ -= tif->tif_scanlinesize;
	182	row += tif->tif_scanlinesize;
	183	}
	184	return (1);
	185	}
	186
	187	int
	188	TIFFInitThunderScan(TIFF* tif, int scheme)
	189	{
	190	(void) scheme;
	191
	192	tif->tif_setupdecode = ThunderSetupDecode;
	193	tif->tif_decoderow = ThunderDecodeRow;
	194	tif->tif_decodestrip = ThunderDecodeRow;
	195	return (1);
	196	}
	197	#endif /* THUNDER_SUPPORT */
	198
	199	/* vim: set ts=8 sts=8 sw=8 noet: */
	200	/*
	201	* Local Variables:
	202	* mode: c
	203	* c-basic-offset: 8
	204	* fill-column: 78
	205	* End:
	206	*/