src/tiff/tif_packbits.c

/* $Header$ */

/*
 * 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 PACKBITS_SUPPORT
/*
 * TIFF Library.
 *
 * PackBits Compression Algorithm Support
 */
#include <assert.h>
#include <stdio.h>

static int
PackBitsPreEncode(TIFF* tif, tsample_t s)
{
	(void) s;
	/*
	 * Calculate the scanline/tile-width size in bytes.
	 */
	if (isTiled(tif))
		tif->tif_data = (tidata_t) TIFFTileRowSize(tif);
	else
		tif->tif_data = (tidata_t) TIFFScanlineSize(tif);
	return (1);
}

/*
 * NB: tidata is the type representing *(tidata_t);
 *     if tidata_t is made signed then this type must
 *     be adjusted accordingly.
 */
typedef unsigned char tidata;

/*
 * Encode a run of pixels.
 */
static int LINKAGEMODE
PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
{
	u_char* bp = (u_char*) buf;
	tidata_t op, ep, lastliteral;
	long n, slop;
	int b;
	enum { BASE, LITERAL, RUN, LITERAL_RUN } state;

	(void) s;
	op = tif->tif_rawcp;
	ep = tif->tif_rawdata + tif->tif_rawdatasize;
	state = BASE;
	lastliteral = 0;
	while (cc > 0) {
		/*
		 * Find the longest string of identical bytes.
		 */
		b = *bp++, cc--, n = 1;
		for (; cc > 0 && b == *bp; cc--, bp++)
			n++;
	again:
		if (op + 2 >= ep) {		/* insure space for new data */
			/*
			 * Be careful about writing the last
			 * literal.  Must write up to that point
			 * and then copy the remainder to the
			 * front of the buffer.
			 */
			if (state == LITERAL || state == LITERAL_RUN) {
				slop = op - lastliteral;
				tif->tif_rawcc += lastliteral - tif->tif_rawcp;
				if (!TIFFFlushData1(tif))
					return (-1);
				op = tif->tif_rawcp;
				while (slop-- > 0)
					*op++ = *lastliteral++;
				lastliteral = tif->tif_rawcp;
			} else {
				tif->tif_rawcc += op - tif->tif_rawcp;
				if (!TIFFFlushData1(tif))
					return (-1);
				op = tif->tif_rawcp;
			}
		}
		switch (state) {
		case BASE:		/* initial state, set run/literal */
			if (n > 1) {
				state = RUN;
				if (n > 128) {
					*op++ = (tidata) -127;
					*op++ = b;
					n -= 128;
					goto again;
				}
				*op++ = (tidataval_t)(-(n-1));
				*op++ = b;
			} else {
				lastliteral = op;
				*op++ = 0;
				*op++ = b;
				state = LITERAL;
			}
			break;
		case LITERAL:		/* last object was literal string */
			if (n > 1) {
				state = LITERAL_RUN;
				if (n > 128) {
					*op++ = (tidata) -127;
					*op++ = b;
					n -= 128;
					goto again;
				}
				*op++ = (tidataval_t)(-(n-1));	/* encode run */
				*op++ = b;
			} else {			/* extend literal */
				if (++(*lastliteral) == 127)
					state = BASE;
				*op++ = b;
			}
			break;
		case RUN:		/* last object was run */
			if (n > 1) {
				if (n > 128) {
					*op++ = (tidata) -127;
					*op++ = b;
					n -= 128;
					goto again;
				}
				*op++ = (tidataval_t)(-(n-1));
				*op++ = b;
			} else {
				lastliteral = op;
				*op++ = 0;
				*op++ = b;
				state = LITERAL;
			}
			break;
		case LITERAL_RUN:	/* literal followed by a run */
			/*
			 * Check to see if previous run should
			 * be converted to a literal, in which
			 * case we convert literal-run-literal
			 * to a single literal.
			 */
			if (n == 1 && op[-2] == (tidata) -1 &&
			    *lastliteral < 126) {
				state = (((*lastliteral) += 2) == 127 ?
				    BASE : LITERAL);
				op[-2] = op[-1];	/* replicate */
			} else
				state = RUN;
			goto again;
		}
	}
	tif->tif_rawcc += op - tif->tif_rawcp;
	tif->tif_rawcp = op;
	return (1);
}

/*
 * Encode a rectangular chunk of pixels.  We break it up
 * into row-sized pieces to insure that encoded runs do
 * not span rows.  Otherwise, there can be problems with
 * the decoder if data is read, for example, by scanlines
 * when it was encoded by strips.
 */
static int LINKAGEMODE
PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	tsize_t rowsize = (tsize_t) tif->tif_data;

	assert(rowsize > 0);
	while ((long)cc > 0) {
		if (PackBitsEncode(tif, bp, rowsize, s) < 0)
			return (-1);
		bp += rowsize;
		cc -= rowsize;
	}
	return (1);
}

static int LINKAGEMODE
PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
	char *bp;
	tsize_t cc;
	long n;
	int b;

	(void) s;
	bp = (char*) tif->tif_rawcp;
	cc = tif->tif_rawcc;
	while (cc > 0 && (long)occ > 0) {
		n = (long) *bp++, cc--;
		/*
		 * Watch out for compilers that
		 * don't sign extend chars...
		 */
		if (n >= 128)
			n -= 256;
		if (n < 0) {		/* replicate next byte -n+1 times */
			if (n == -128)	/* nop */
				continue;
			n = -n + 1;
			occ -= n;
			b = *bp++, cc--;
			while (n-- > 0)
				*op++ = b;
		} else {		/* copy next n+1 bytes literally */
			_TIFFmemcpy(op, bp, ++n);
			op += n; occ -= n;
			bp += n; cc -= n;
		}
	}
	tif->tif_rawcp = (tidata_t) bp;
	tif->tif_rawcc = cc;
	if (occ > 0) {
		TIFFError(tif->tif_name,
		    "PackBitsDecode: Not enough data for scanline %ld",
		    (long) tif->tif_row);
		return (0);
	}
	/* check for buffer overruns? */
	return (1);
}

int
TIFFInitPackBits(TIFF* tif, int scheme)
{
	(void) scheme;
	tif->tif_decoderow = PackBitsDecode;
	tif->tif_decodestrip = PackBitsDecode;
	tif->tif_decodetile = PackBitsDecode;
	tif->tif_preencode = PackBitsPreEncode;
	tif->tif_encoderow = PackBitsEncode;
	tif->tif_encodestrip = PackBitsEncodeChunk;
	tif->tif_encodetile = PackBitsEncodeChunk;
	return (1);
}
#endif /* PACKBITS_SUPPORT */
Commit	Line	Data
	1	/* $Header$ */
	2
	3	/*
	4	* Copyright (c) 1988-1997 Sam Leffler
	5	* Copyright (c) 1991-1997 Silicon Graphics, Inc.
	6	*
	7	* Permission to use, copy, modify, distribute, and sell this software and
	8	* its documentation for any purpose is hereby granted without fee, provided
	9	* that (i) the above copyright notices and this permission notice appear in
	10	* all copies of the software and related documentation, and (ii) the names of
	11	* Sam Leffler and Silicon Graphics may not be used in any advertising or
	12	* publicity relating to the software without the specific, prior written
	13	* permission of Sam Leffler and Silicon Graphics.
	14	*
	15	* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	16	* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	17	* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	18	*
	19	* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	20	* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	21	* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	22	* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	23	* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	24	* OF THIS SOFTWARE.
	25	*/
	26
	27	#include "tiffiop.h"
	28	#ifdef PACKBITS_SUPPORT
	29	/*
	30	* TIFF Library.
	31	*
	32	* PackBits Compression Algorithm Support
	33	*/
	34	#include <assert.h>
	35	#include <stdio.h>
	36
	37	static int
	38	PackBitsPreEncode(TIFF* tif, tsample_t s)
	39	{
	40	(void) s;
	41	/*
	42	* Calculate the scanline/tile-width size in bytes.
	43	*/
	44	if (isTiled(tif))
	45	tif->tif_data = (tidata_t) TIFFTileRowSize(tif);
	46	else
	47	tif->tif_data = (tidata_t) TIFFScanlineSize(tif);
	48	return (1);
	49	}
	50
	51	/*
	52	* NB: tidata is the type representing *(tidata_t);
	53	* if tidata_t is made signed then this type must
	54	* be adjusted accordingly.
	55	*/
	56	typedef unsigned char tidata;
	57
	58	/*
	59	* Encode a run of pixels.
	60	*/
	61	static int LINKAGEMODE
	62	PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
	63	{
	64	u_char* bp = (u_char*) buf;
	65	tidata_t op, ep, lastliteral;
	66	long n, slop;
	67	int b;
	68	enum { BASE, LITERAL, RUN, LITERAL_RUN } state;
	69
	70	(void) s;
	71	op = tif->tif_rawcp;
	72	ep = tif->tif_rawdata + tif->tif_rawdatasize;
	73	state = BASE;
	74	lastliteral = 0;
	75	while (cc > 0) {
	76	/*
	77	* Find the longest string of identical bytes.
	78	*/
	79	b = *bp++, cc--, n = 1;
	80	for (; cc > 0 && b == *bp; cc--, bp++)
	81	n++;
	82	again:
	83	if (op + 2 >= ep) { /* insure space for new data */
	84	/*
	85	* Be careful about writing the last
	86	* literal. Must write up to that point
	87	* and then copy the remainder to the
	88	* front of the buffer.
	89	*/
	90	if (state == LITERAL \|\| state == LITERAL_RUN) {
	91	slop = op - lastliteral;
	92	tif->tif_rawcc += lastliteral - tif->tif_rawcp;
	93	if (!TIFFFlushData1(tif))
	94	return (-1);
	95	op = tif->tif_rawcp;
	96	while (slop-- > 0)
	97	op++ = lastliteral++;
	98	lastliteral = tif->tif_rawcp;
	99	} else {
	100	tif->tif_rawcc += op - tif->tif_rawcp;
	101	if (!TIFFFlushData1(tif))
	102	return (-1);
	103	op = tif->tif_rawcp;
	104	}
	105	}
	106	switch (state) {
	107	case BASE: /* initial state, set run/literal */
	108	if (n > 1) {
	109	state = RUN;
	110	if (n > 128) {
	111	*op++ = (tidata) -127;
	112	*op++ = b;
	113	n -= 128;
	114	goto again;
	115	}
	116	*op++ = (tidataval_t)(-(n-1));
	117	*op++ = b;
	118	} else {
	119	lastliteral = op;
	120	*op++ = 0;
	121	*op++ = b;
	122	state = LITERAL;
	123	}
	124	break;
	125	case LITERAL: /* last object was literal string */
	126	if (n > 1) {
	127	state = LITERAL_RUN;
	128	if (n > 128) {
	129	*op++ = (tidata) -127;
	130	*op++ = b;
	131	n -= 128;
	132	goto again;
	133	}
	134	op++ = (tidataval_t)(-(n-1)); / encode run */
	135	*op++ = b;
	136	} else { /* extend literal */
	137	if (++(*lastliteral) == 127)
	138	state = BASE;
	139	*op++ = b;
	140	}
	141	break;
	142	case RUN: /* last object was run */
	143	if (n > 1) {
	144	if (n > 128) {
	145	*op++ = (tidata) -127;
	146	*op++ = b;
	147	n -= 128;
	148	goto again;
	149	}
	150	*op++ = (tidataval_t)(-(n-1));
	151	*op++ = b;
	152	} else {
	153	lastliteral = op;
	154	*op++ = 0;
	155	*op++ = b;
	156	state = LITERAL;
	157	}
	158	break;
	159	case LITERAL_RUN: /* literal followed by a run */
	160	/*
	161	* Check to see if previous run should
	162	* be converted to a literal, in which
	163	* case we convert literal-run-literal
	164	* to a single literal.
	165	*/
	166	if (n == 1 && op[-2] == (tidata) -1 &&
	167	*lastliteral < 126) {
	168	state = (((*lastliteral) += 2) == 127 ?
	169	BASE : LITERAL);
	170	op[-2] = op[-1]; /* replicate */
	171	} else
	172	state = RUN;
	173	goto again;
	174	}
	175	}
	176	tif->tif_rawcc += op - tif->tif_rawcp;
	177	tif->tif_rawcp = op;
	178	return (1);
	179	}
	180
	181	/*
	182	* Encode a rectangular chunk of pixels. We break it up
	183	* into row-sized pieces to insure that encoded runs do
	184	* not span rows. Otherwise, there can be problems with
	185	* the decoder if data is read, for example, by scanlines
	186	* when it was encoded by strips.
	187	*/
	188	static int LINKAGEMODE
	189	PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
	190	{
	191	tsize_t rowsize = (tsize_t) tif->tif_data;
	192
	193	assert(rowsize > 0);
	194	while ((long)cc > 0) {
	195	if (PackBitsEncode(tif, bp, rowsize, s) < 0)
	196	return (-1);
	197	bp += rowsize;
	198	cc -= rowsize;
	199	}
	200	return (1);
	201	}
	202
	203	static int LINKAGEMODE
	204	PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
	205	{
	206	char *bp;
	207	tsize_t cc;
	208	long n;
	209	int b;
	210
	211	(void) s;
	212	bp = (char*) tif->tif_rawcp;
	213	cc = tif->tif_rawcc;
	214	while (cc > 0 && (long)occ > 0) {
	215	n = (long) *bp++, cc--;
	216	/*
	217	* Watch out for compilers that
	218	* don't sign extend chars...
	219	*/
	220	if (n >= 128)
	221	n -= 256;
	222	if (n < 0) { /* replicate next byte -n+1 times */
	223	if (n == -128) /* nop */
	224	continue;
	225	n = -n + 1;
	226	occ -= n;
	227	b = *bp++, cc--;
	228	while (n-- > 0)
	229	*op++ = b;
	230	} else { /* copy next n+1 bytes literally */
	231	_TIFFmemcpy(op, bp, ++n);
	232	op += n; occ -= n;
	233	bp += n; cc -= n;
	234	}
	235	}
	236	tif->tif_rawcp = (tidata_t) bp;
	237	tif->tif_rawcc = cc;
	238	if (occ > 0) {
	239	TIFFError(tif->tif_name,
	240	"PackBitsDecode: Not enough data for scanline %ld",
	241	(long) tif->tif_row);
	242	return (0);
	243	}
	244	/* check for buffer overruns? */
	245	return (1);
	246	}
	247
	248	int
	249	TIFFInitPackBits(TIFF* tif, int scheme)
	250	{
	251	(void) scheme;
	252	tif->tif_decoderow = PackBitsDecode;
	253	tif->tif_decodestrip = PackBitsDecode;
	254	tif->tif_decodetile = PackBitsDecode;
	255	tif->tif_preencode = PackBitsPreEncode;
	256	tif->tif_encoderow = PackBitsEncode;
	257	tif->tif_encodestrip = PackBitsEncodeChunk;
	258	tif->tif_encodetile = PackBitsEncodeChunk;
	259	return (1);
	260	}
	261	#endif /* PACKBITS_SUPPORT */