src/tiff/tif_predict.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.
 */

/*
 * TIFF Library.
 *
 * Predictor Tag Support (used by multiple codecs).
 */
#include "tiffiop.h"
/* Watcom C++ (or its make utility) doesn't like long filenames */
#ifdef wxUSE_SHORTNAMES
#include "tif_pred.h"
#else
#include "tif_predict.h"
#endif

#include <assert.h>

#define	PredictorState(tif)	((TIFFPredictorState*) (tif)->tif_data)

static	void LINKAGEMODE horAcc8(TIFF*, tidata_t, tsize_t);
static	void LINKAGEMODE horAcc16(TIFF*, tidata_t, tsize_t);
static	void LINKAGEMODE swabHorAcc16(TIFF*, tidata_t, tsize_t);
static	void LINKAGEMODE horDiff8(TIFF*, tidata_t, tsize_t);
static	void LINKAGEMODE horDiff16(TIFF*, tidata_t, tsize_t);
static	int LINKAGEMODE PredictorDecodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
static	int LINKAGEMODE PredictorDecodeTile(TIFF*, tidata_t, tsize_t, tsample_t);
static	int LINKAGEMODE PredictorEncodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
static	int LINKAGEMODE PredictorEncodeTile(TIFF*, tidata_t, tsize_t, tsample_t);

static int
PredictorSetup(TIFF* tif)
{
	TIFFPredictorState* sp = PredictorState(tif);
	TIFFDirectory* td = &tif->tif_dir;

	if (sp->predictor == 1)		/* no differencing */
		return (1);
	if (sp->predictor != 2) {
		TIFFError(tif->tif_name, "\"Predictor\" value %d not supported",
		    sp->predictor);
		return (0);
	}
	if (td->td_bitspersample != 8 && td->td_bitspersample != 16) {
		TIFFError(tif->tif_name,
    "Horizontal differencing \"Predictor\" not supported with %d-bit samples",
		    td->td_bitspersample);
		return (0);
	}
	sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
	    td->td_samplesperpixel : 1);
	/*
	 * Calculate the scanline/tile-width size in bytes.
	 */
	if (isTiled(tif))
		sp->rowsize = TIFFTileRowSize(tif);
	else
		sp->rowsize = TIFFScanlineSize(tif);
	return (1);
}

static int
PredictorSetupDecode(TIFF* tif)
{
	TIFFPredictorState* sp = PredictorState(tif);
	TIFFDirectory* td = &tif->tif_dir;

	if (!(*sp->setupdecode)(tif) || !PredictorSetup(tif))
		return (0);
	if (sp->predictor == 2) {
		switch (td->td_bitspersample) {
		case 8:  sp->pfunc = horAcc8; break;
		case 16: sp->pfunc = horAcc16; break;
		}
		/*
		 * Override default decoding method with
		 * one that does the predictor stuff.
		 */
		sp->coderow = tif->tif_decoderow;
		tif->tif_decoderow = PredictorDecodeRow;
		sp->codestrip = tif->tif_decodestrip;
		tif->tif_decodestrip = PredictorDecodeTile;
		sp->codetile = tif->tif_decodetile;
		tif->tif_decodetile = PredictorDecodeTile;
		/*
		 * If the data is horizontally differenced
		 * 16-bit data that requires byte-swapping,
		 * then it must be byte swapped before the
		 * accumulation step.  We do this with a
		 * special-purpose routine and override the
		 * normal post decoding logic that the library
		 * setup when the directory was read.
		 */
		if (tif->tif_flags&TIFF_SWAB) {
			if (sp->pfunc == horAcc16) {
				sp->pfunc = swabHorAcc16;
				tif->tif_postdecode = _TIFFNoPostDecode;
			} /* else handle 32-bit case... */
		}
	}
	return (1);
}

static int
PredictorSetupEncode(TIFF* tif)
{
	TIFFPredictorState* sp = PredictorState(tif);
	TIFFDirectory* td = &tif->tif_dir;

	if (!(*sp->setupencode)(tif) || !PredictorSetup(tif))
		return (0);
	if (sp->predictor == 2) {
		switch (td->td_bitspersample) {
		case 8:  sp->pfunc = horDiff8; break;
		case 16: sp->pfunc = horDiff16; break;
		}
		/*
		 * Override default encoding method with
		 * one that does the predictor stuff.
		 */
		sp->coderow = tif->tif_encoderow;
		tif->tif_encoderow = PredictorEncodeRow;
		sp->codestrip = tif->tif_encodestrip;
		tif->tif_encodestrip = PredictorEncodeTile;
		sp->codetile = tif->tif_encodetile;
		tif->tif_encodetile = PredictorEncodeTile;
	}
	return (1);
}

#define REPEAT4(n, op)		\
    switch (n) {		\
    default: { int i; for (i = n-4; i > 0; i--) { op; } } \
    case 4:  op;		\
    case 3:  op;		\
    case 2:  op;		\
    case 1:  op;		\
    case 0:  ;			\
    }

static void
horAcc8(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	TIFFPredictorState* sp = PredictorState(tif);
	u_int stride = sp->stride;

	char* cp = (char*) cp0;
	if (cc > stride) {
		cc -= stride;
		/*
		 * Pipeline the most common cases.
		 */
		if (stride == 3)  {
			u_int cr = cp[0];
			u_int cg = cp[1];
			u_int cb = cp[2];
			do {
				cc -= 3, cp += 3;
				cp[0] = (cr += cp[0]);
				cp[1] = (cg += cp[1]);
				cp[2] = (cb += cp[2]);
			} while ((int32) cc > 0);
		} else if (stride == 4)  {
			u_int cr = cp[0];
			u_int cg = cp[1];
			u_int cb = cp[2];
			u_int ca = cp[3];
			do {
				cc -= 4, cp += 4;
				cp[0] = (cr += cp[0]);
				cp[1] = (cg += cp[1]);
				cp[2] = (cb += cp[2]);
				cp[3] = (ca += cp[3]);
			} while ((int32) cc > 0);
		} else  {
			do {
				REPEAT4(stride, cp[stride] += *cp; cp++)
				cc -= stride;
			} while ((int32) cc > 0);
		}
	}
}

static void
swabHorAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	TIFFPredictorState* sp = PredictorState(tif);
	u_int stride = sp->stride;
	uint16* wp = (uint16*) cp0;
	tsize_t wc = cc / 2;

	if (wc > stride) {
		TIFFSwabArrayOfShort(wp, wc);
		wc -= stride;
		do {
			REPEAT4(stride, wp[stride] += wp[0]; wp++)
			wc -= stride;
		} while ((int32) wc > 0);
	}
}

static void
horAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	u_int stride = PredictorState(tif)->stride;
	uint16* wp = (uint16*) cp0;
	tsize_t wc = cc / 2;

	if (wc > stride) {
		wc -= stride;
		do {
			REPEAT4(stride, wp[stride] += wp[0]; wp++)
			wc -= stride;
		} while ((int32) wc > 0);
	}
}

/*
 * Decode a scanline and apply the predictor routine.
 */
static int
PredictorDecodeRow(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
{
	TIFFPredictorState *sp = PredictorState(tif);

	assert(sp != NULL);
	assert(sp->coderow != NULL);
	assert(sp->pfunc != NULL);
	if ((*sp->coderow)(tif, op0, occ0, s)) {
		(*sp->pfunc)(tif, op0, occ0);
		return (1);
	} else
		return (0);
}

/*
 * Decode a tile/strip and apply the predictor routine.
 * Note that horizontal differencing must be done on a
 * row-by-row basis.  The width of a "row" has already
 * been calculated at pre-decode time according to the
 * strip/tile dimensions.
 */
static int
PredictorDecodeTile(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
{
	TIFFPredictorState *sp = PredictorState(tif);

	assert(sp != NULL);
	assert(sp->codetile != NULL);
	if ((*sp->codetile)(tif, op0, occ0, s)) {
		tsize_t rowsize = sp->rowsize;
		assert(rowsize > 0);
		assert(sp->pfunc != NULL);
		while ((long)occ0 > 0) {
			(*sp->pfunc)(tif, op0, (tsize_t) rowsize);
			occ0 -= rowsize;
			op0 += rowsize;
		}
		return (1);
	} else
		return (0);
}

static void
horDiff8(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	TIFFPredictorState* sp = PredictorState(tif);
	u_int stride = sp->stride;
	char* cp = (char*) cp0;

	if (cc > stride) {
		cc -= stride;
		/*
		 * Pipeline the most common cases.
		 */
		if (stride == 3) {
			int r1, g1, b1;
			int r2 = cp[0];
			int g2 = cp[1];
			int b2 = cp[2];
			do {
				r1 = cp[3]; cp[3] = r1-r2; r2 = r1;
				g1 = cp[4]; cp[4] = g1-g2; g2 = g1;
				b1 = cp[5]; cp[5] = b1-b2; b2 = b1;
				cp += 3;
			} while ((int32)(cc -= 3) > 0);
		} else if (stride == 4) {
			int r1, g1, b1, a1;
			int r2 = cp[0];
			int g2 = cp[1];
			int b2 = cp[2];
			int a2 = cp[3];
			do {
				r1 = cp[4]; cp[4] = r1-r2; r2 = r1;
				g1 = cp[5]; cp[5] = g1-g2; g2 = g1;
				b1 = cp[6]; cp[6] = b1-b2; b2 = b1;
				a1 = cp[7]; cp[7] = a1-a2; a2 = a1;
				cp += 4;
			} while ((int32)(cc -= 4) > 0);
		} else {
			cp += cc - 1;
			do {
				REPEAT4(stride, cp[stride] -= cp[0]; cp--)
			} while ((int32)(cc -= stride) > 0);
		}
	}
}

static void
horDiff16(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	TIFFPredictorState* sp = PredictorState(tif);
	u_int stride = sp->stride;
	int16 *wp = (int16*) cp0;
	tsize_t wc = cc/2;

	if (wc > stride) {
		wc -= stride;
		wp += wc - 1;
		do {
			REPEAT4(stride, wp[stride] -= wp[0]; wp--)
			wc -= stride;
		} while ((int32) wc > 0);
	}
}

static int
PredictorEncodeRow(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	TIFFPredictorState *sp = PredictorState(tif);

	assert(sp != NULL);
	assert(sp->pfunc != NULL);
	assert(sp->coderow != NULL);
/* XXX horizontal differencing alters user's data XXX */
	(*sp->pfunc)(tif, bp, cc);
	return ((*sp->coderow)(tif, bp, cc, s));
}

static int
PredictorEncodeTile(TIFF* tif, tidata_t bp0, tsize_t cc0, tsample_t s)
{
	TIFFPredictorState *sp = PredictorState(tif);
	tsize_t cc = cc0, rowsize;
	u_char* bp = bp0;

	assert(sp != NULL);
	assert(sp->pfunc != NULL);
	assert(sp->codetile != NULL);
	rowsize = sp->rowsize;
	assert(rowsize > 0);
	while ((long)cc > 0) {
		(*sp->pfunc)(tif, bp, (tsize_t) rowsize);
		cc -= rowsize;
		bp += rowsize;
	}
	return ((*sp->codetile)(tif, bp0, cc0, s));
}

#define	FIELD_PREDICTOR	(FIELD_CODEC+0)		/* XXX */

static const TIFFFieldInfo predictFieldInfo[] = {
    { TIFFTAG_PREDICTOR,	 1, 1, TIFF_SHORT,	FIELD_PREDICTOR,
      FALSE,	FALSE,	"Predictor" },
};
#define	N(a)	(sizeof (a) / sizeof (a[0]))

static int
PredictorVSetField(TIFF* tif, ttag_t tag, va_list ap)
{
	TIFFPredictorState *sp = PredictorState(tif);

	switch (tag) {
	case TIFFTAG_PREDICTOR:
		sp->predictor = (uint16) va_arg(ap, int);
		TIFFSetFieldBit(tif, FIELD_PREDICTOR);
		break;
	default:
		return (*sp->vsetparent)(tif, tag, ap);
	}
	tif->tif_flags |= TIFF_DIRTYDIRECT;
	return (1);
}

static int
PredictorVGetField(TIFF* tif, ttag_t tag, va_list ap)
{
	TIFFPredictorState *sp = PredictorState(tif);

	switch (tag) {
	case TIFFTAG_PREDICTOR:
		*va_arg(ap, uint16*) = sp->predictor;
		break;
	default:
		return (*sp->vgetparent)(tif, tag, ap);
	}
	return (1);
}

static void LINKAGEMODE
PredictorPrintDir(TIFF* tif, FILE* fd, long flags)
{
	TIFFPredictorState* sp = PredictorState(tif);

	(void) flags;
	if (TIFFFieldSet(tif,FIELD_PREDICTOR)) {
		fprintf(fd, "  Predictor: ");
		switch (sp->predictor) {
		case 1: fprintf(fd, "none "); break;
		case 2: fprintf(fd, "horizontal differencing "); break;
		}
		fprintf(fd, "%u (0x%x)\n", sp->predictor, sp->predictor);
	}
	if (sp->printdir)
		(*sp->printdir)(tif, fd, flags);
}

int
TIFFPredictorInit(TIFF* tif)
{
	TIFFPredictorState* sp = PredictorState(tif);

	/*
	 * Merge codec-specific tag information and
	 * override parent get/set field methods.
	 */
	_TIFFMergeFieldInfo(tif, predictFieldInfo, N(predictFieldInfo));
	sp->vgetparent = tif->tif_vgetfield;
	tif->tif_vgetfield = PredictorVGetField;/* hook for predictor tag */
	sp->vsetparent = tif->tif_vsetfield;
	tif->tif_vsetfield = PredictorVSetField;/* hook for predictor tag */
	sp->printdir = tif->tif_printdir;
	tif->tif_printdir = PredictorPrintDir;	/* hook for predictor tag */

	sp->setupdecode = tif->tif_setupdecode;
	tif->tif_setupdecode = PredictorSetupDecode;
	sp->setupencode = tif->tif_setupencode;
	tif->tif_setupencode = PredictorSetupEncode;

	sp->predictor = 1;			/* default value */
	sp->pfunc = NULL;			/* no predictor routine */
	return (1);
}
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	/*
	28	* TIFF Library.
	29	*
	30	* Predictor Tag Support (used by multiple codecs).
	31	*/
	32	#include "tiffiop.h"
	33	/* Watcom C++ (or its make utility) doesn't like long filenames */
	34	#ifdef wxUSE_SHORTNAMES
	35	#include "tif_pred.h"
	36	#else
	37	#include "tif_predict.h"
	38	#endif
	39
	40	#include <assert.h>
	41
	42	#define PredictorState(tif) ((TIFFPredictorState*) (tif)->tif_data)
	43
	44	static void LINKAGEMODE horAcc8(TIFF*, tidata_t, tsize_t);
	45	static void LINKAGEMODE horAcc16(TIFF*, tidata_t, tsize_t);
	46	static void LINKAGEMODE swabHorAcc16(TIFF*, tidata_t, tsize_t);
	47	static void LINKAGEMODE horDiff8(TIFF*, tidata_t, tsize_t);
	48	static void LINKAGEMODE horDiff16(TIFF*, tidata_t, tsize_t);
	49	static int LINKAGEMODE PredictorDecodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
	50	static int LINKAGEMODE PredictorDecodeTile(TIFF*, tidata_t, tsize_t, tsample_t);
	51	static int LINKAGEMODE PredictorEncodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
	52	static int LINKAGEMODE PredictorEncodeTile(TIFF*, tidata_t, tsize_t, tsample_t);
	53
	54	static int
	55	PredictorSetup(TIFF* tif)
	56	{
	57	TIFFPredictorState* sp = PredictorState(tif);
	58	TIFFDirectory* td = &tif->tif_dir;
	59
	60	if (sp->predictor == 1) /* no differencing */
	61	return (1);
	62	if (sp->predictor != 2) {
	63	TIFFError(tif->tif_name, "\"Predictor\" value %d not supported",
	64	sp->predictor);
	65	return (0);
	66	}
	67	if (td->td_bitspersample != 8 && td->td_bitspersample != 16) {
	68	TIFFError(tif->tif_name,
	69	"Horizontal differencing \"Predictor\" not supported with %d-bit samples",
	70	td->td_bitspersample);
	71	return (0);
	72	}
	73	sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
	74	td->td_samplesperpixel : 1);
	75	/*
	76	* Calculate the scanline/tile-width size in bytes.
	77	*/
	78	if (isTiled(tif))
	79	sp->rowsize = TIFFTileRowSize(tif);
	80	else
	81	sp->rowsize = TIFFScanlineSize(tif);
	82	return (1);
	83	}
	84
	85	static int
	86	PredictorSetupDecode(TIFF* tif)
	87	{
	88	TIFFPredictorState* sp = PredictorState(tif);
	89	TIFFDirectory* td = &tif->tif_dir;
	90
	91	if (!(*sp->setupdecode)(tif) \|\| !PredictorSetup(tif))
	92	return (0);
	93	if (sp->predictor == 2) {
	94	switch (td->td_bitspersample) {
	95	case 8: sp->pfunc = horAcc8; break;
	96	case 16: sp->pfunc = horAcc16; break;
	97	}
	98	/*
	99	* Override default decoding method with
	100	* one that does the predictor stuff.
	101	*/
	102	sp->coderow = tif->tif_decoderow;
	103	tif->tif_decoderow = PredictorDecodeRow;
	104	sp->codestrip = tif->tif_decodestrip;
	105	tif->tif_decodestrip = PredictorDecodeTile;
	106	sp->codetile = tif->tif_decodetile;
	107	tif->tif_decodetile = PredictorDecodeTile;
	108	/*
	109	* If the data is horizontally differenced
	110	* 16-bit data that requires byte-swapping,
	111	* then it must be byte swapped before the
	112	* accumulation step. We do this with a
	113	* special-purpose routine and override the
	114	* normal post decoding logic that the library
	115	* setup when the directory was read.
	116	*/
	117	if (tif->tif_flags&TIFF_SWAB) {
	118	if (sp->pfunc == horAcc16) {
	119	sp->pfunc = swabHorAcc16;
	120	tif->tif_postdecode = _TIFFNoPostDecode;
	121	} /* else handle 32-bit case... */
	122	}
	123	}
	124	return (1);
	125	}
	126
	127	static int
	128	PredictorSetupEncode(TIFF* tif)
	129	{
	130	TIFFPredictorState* sp = PredictorState(tif);
	131	TIFFDirectory* td = &tif->tif_dir;
	132
	133	if (!(*sp->setupencode)(tif) \|\| !PredictorSetup(tif))
	134	return (0);
	135	if (sp->predictor == 2) {
	136	switch (td->td_bitspersample) {
	137	case 8: sp->pfunc = horDiff8; break;
	138	case 16: sp->pfunc = horDiff16; break;
	139	}
	140	/*
	141	* Override default encoding method with
	142	* one that does the predictor stuff.
	143	*/
	144	sp->coderow = tif->tif_encoderow;
	145	tif->tif_encoderow = PredictorEncodeRow;
	146	sp->codestrip = tif->tif_encodestrip;
	147	tif->tif_encodestrip = PredictorEncodeTile;
	148	sp->codetile = tif->tif_encodetile;
	149	tif->tif_encodetile = PredictorEncodeTile;
	150	}
	151	return (1);
	152	}
	153
	154	#define REPEAT4(n, op) \
	155	switch (n) { \
	156	default: { int i; for (i = n-4; i > 0; i--) { op; } } \
	157	case 4: op; \
	158	case 3: op; \
	159	case 2: op; \
	160	case 1: op; \
	161	case 0: ; \
	162	}
	163
	164	static void
	165	horAcc8(TIFF* tif, tidata_t cp0, tsize_t cc)
	166	{
	167	TIFFPredictorState* sp = PredictorState(tif);
	168	u_int stride = sp->stride;
	169
	170	char* cp = (char*) cp0;
	171	if (cc > stride) {
	172	cc -= stride;
	173	/*
	174	* Pipeline the most common cases.
	175	*/
	176	if (stride == 3) {
	177	u_int cr = cp[0];
	178	u_int cg = cp[1];
	179	u_int cb = cp[2];
	180	do {
	181	cc -= 3, cp += 3;
	182	cp[0] = (cr += cp[0]);
	183	cp[1] = (cg += cp[1]);
	184	cp[2] = (cb += cp[2]);
	185	} while ((int32) cc > 0);
	186	} else if (stride == 4) {
	187	u_int cr = cp[0];
	188	u_int cg = cp[1];
	189	u_int cb = cp[2];
	190	u_int ca = cp[3];
	191	do {
	192	cc -= 4, cp += 4;
	193	cp[0] = (cr += cp[0]);
	194	cp[1] = (cg += cp[1]);
	195	cp[2] = (cb += cp[2]);
	196	cp[3] = (ca += cp[3]);
	197	} while ((int32) cc > 0);
	198	} else {
	199	do {
	200	REPEAT4(stride, cp[stride] += *cp; cp++)
	201	cc -= stride;
	202	} while ((int32) cc > 0);
	203	}
	204	}
	205	}
	206
	207	static void
	208	swabHorAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
	209	{
	210	TIFFPredictorState* sp = PredictorState(tif);
	211	u_int stride = sp->stride;
	212	uint16* wp = (uint16*) cp0;
	213	tsize_t wc = cc / 2;
	214
	215	if (wc > stride) {
	216	TIFFSwabArrayOfShort(wp, wc);
	217	wc -= stride;
	218	do {
	219	REPEAT4(stride, wp[stride] += wp[0]; wp++)
	220	wc -= stride;
	221	} while ((int32) wc > 0);
	222	}
	223	}
	224
	225	static void
	226	horAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
	227	{
	228	u_int stride = PredictorState(tif)->stride;
	229	uint16* wp = (uint16*) cp0;
	230	tsize_t wc = cc / 2;
	231
	232	if (wc > stride) {
	233	wc -= stride;
	234	do {
	235	REPEAT4(stride, wp[stride] += wp[0]; wp++)
	236	wc -= stride;
	237	} while ((int32) wc > 0);
	238	}
	239	}
	240
	241	/*
	242	* Decode a scanline and apply the predictor routine.
	243	*/
	244	static int
	245	PredictorDecodeRow(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
	246	{
	247	TIFFPredictorState *sp = PredictorState(tif);
	248
	249	assert(sp != NULL);
	250	assert(sp->coderow != NULL);
	251	assert(sp->pfunc != NULL);
	252	if ((*sp->coderow)(tif, op0, occ0, s)) {
	253	(*sp->pfunc)(tif, op0, occ0);
	254	return (1);
	255	} else
	256	return (0);
	257	}
	258
	259	/*
	260	* Decode a tile/strip and apply the predictor routine.
	261	* Note that horizontal differencing must be done on a
	262	* row-by-row basis. The width of a "row" has already
	263	* been calculated at pre-decode time according to the
	264	* strip/tile dimensions.
	265	*/
	266	static int
	267	PredictorDecodeTile(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
	268	{
	269	TIFFPredictorState *sp = PredictorState(tif);
	270
	271	assert(sp != NULL);
	272	assert(sp->codetile != NULL);
	273	if ((*sp->codetile)(tif, op0, occ0, s)) {
	274	tsize_t rowsize = sp->rowsize;
	275	assert(rowsize > 0);
	276	assert(sp->pfunc != NULL);
	277	while ((long)occ0 > 0) {
	278	(*sp->pfunc)(tif, op0, (tsize_t) rowsize);
	279	occ0 -= rowsize;
	280	op0 += rowsize;
	281	}
	282	return (1);
	283	} else
	284	return (0);
	285	}
	286
	287	static void
	288	horDiff8(TIFF* tif, tidata_t cp0, tsize_t cc)
	289	{
	290	TIFFPredictorState* sp = PredictorState(tif);
	291	u_int stride = sp->stride;
	292	char* cp = (char*) cp0;
	293
	294	if (cc > stride) {
	295	cc -= stride;
	296	/*
	297	* Pipeline the most common cases.
	298	*/
	299	if (stride == 3) {
	300	int r1, g1, b1;
	301	int r2 = cp[0];
	302	int g2 = cp[1];
	303	int b2 = cp[2];
	304	do {
	305	r1 = cp[3]; cp[3] = r1-r2; r2 = r1;
	306	g1 = cp[4]; cp[4] = g1-g2; g2 = g1;
	307	b1 = cp[5]; cp[5] = b1-b2; b2 = b1;
	308	cp += 3;
	309	} while ((int32)(cc -= 3) > 0);
	310	} else if (stride == 4) {
	311	int r1, g1, b1, a1;
	312	int r2 = cp[0];
	313	int g2 = cp[1];
	314	int b2 = cp[2];
	315	int a2 = cp[3];
	316	do {
	317	r1 = cp[4]; cp[4] = r1-r2; r2 = r1;
	318	g1 = cp[5]; cp[5] = g1-g2; g2 = g1;
	319	b1 = cp[6]; cp[6] = b1-b2; b2 = b1;
	320	a1 = cp[7]; cp[7] = a1-a2; a2 = a1;
	321	cp += 4;
	322	} while ((int32)(cc -= 4) > 0);
	323	} else {
	324	cp += cc - 1;
	325	do {
	326	REPEAT4(stride, cp[stride] -= cp[0]; cp--)
	327	} while ((int32)(cc -= stride) > 0);
	328	}
	329	}
	330	}
	331
	332	static void
	333	horDiff16(TIFF* tif, tidata_t cp0, tsize_t cc)
	334	{
	335	TIFFPredictorState* sp = PredictorState(tif);
	336	u_int stride = sp->stride;
	337	int16 wp = (int16) cp0;
	338	tsize_t wc = cc/2;
	339
	340	if (wc > stride) {
	341	wc -= stride;
	342	wp += wc - 1;
	343	do {
	344	REPEAT4(stride, wp[stride] -= wp[0]; wp--)
	345	wc -= stride;
	346	} while ((int32) wc > 0);
	347	}
	348	}
	349
	350	static int
	351	PredictorEncodeRow(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
	352	{
	353	TIFFPredictorState *sp = PredictorState(tif);
	354
	355	assert(sp != NULL);
	356	assert(sp->pfunc != NULL);
	357	assert(sp->coderow != NULL);
	358	/* XXX horizontal differencing alters user's data XXX */
	359	(*sp->pfunc)(tif, bp, cc);
	360	return ((*sp->coderow)(tif, bp, cc, s));
	361	}
	362
	363	static int
	364	PredictorEncodeTile(TIFF* tif, tidata_t bp0, tsize_t cc0, tsample_t s)
	365	{
	366	TIFFPredictorState *sp = PredictorState(tif);
	367	tsize_t cc = cc0, rowsize;
	368	u_char* bp = bp0;
	369
	370	assert(sp != NULL);
	371	assert(sp->pfunc != NULL);
	372	assert(sp->codetile != NULL);
	373	rowsize = sp->rowsize;
	374	assert(rowsize > 0);
	375	while ((long)cc > 0) {
	376	(*sp->pfunc)(tif, bp, (tsize_t) rowsize);
	377	cc -= rowsize;
	378	bp += rowsize;
	379	}
	380	return ((*sp->codetile)(tif, bp0, cc0, s));
	381	}
	382
	383	#define FIELD_PREDICTOR (FIELD_CODEC+0) /* XXX */
	384
	385	static const TIFFFieldInfo predictFieldInfo[] = {
	386	{ TIFFTAG_PREDICTOR, 1, 1, TIFF_SHORT, FIELD_PREDICTOR,
	387	FALSE, FALSE, "Predictor" },
	388	};
	389	#define N(a) (sizeof (a) / sizeof (a[0]))
	390
	391	static int
	392	PredictorVSetField(TIFF* tif, ttag_t tag, va_list ap)
	393	{
	394	TIFFPredictorState *sp = PredictorState(tif);
	395
	396	switch (tag) {
	397	case TIFFTAG_PREDICTOR:
	398	sp->predictor = (uint16) va_arg(ap, int);
	399	TIFFSetFieldBit(tif, FIELD_PREDICTOR);
	400	break;
	401	default:
	402	return (*sp->vsetparent)(tif, tag, ap);
	403	}
	404	tif->tif_flags \|= TIFF_DIRTYDIRECT;
	405	return (1);
	406	}
	407
	408	static int
	409	PredictorVGetField(TIFF* tif, ttag_t tag, va_list ap)
	410	{
	411	TIFFPredictorState *sp = PredictorState(tif);
	412
	413	switch (tag) {
	414	case TIFFTAG_PREDICTOR:
	415	va_arg(ap, uint16) = sp->predictor;
	416	break;
	417	default:
	418	return (*sp->vgetparent)(tif, tag, ap);
	419	}
	420	return (1);
	421	}
	422
	423	static void LINKAGEMODE
	424	PredictorPrintDir(TIFF* tif, FILE* fd, long flags)
	425	{
	426	TIFFPredictorState* sp = PredictorState(tif);
	427
	428	(void) flags;
	429	if (TIFFFieldSet(tif,FIELD_PREDICTOR)) {
	430	fprintf(fd, " Predictor: ");
	431	switch (sp->predictor) {
	432	case 1: fprintf(fd, "none "); break;
	433	case 2: fprintf(fd, "horizontal differencing "); break;
	434	}
	435	fprintf(fd, "%u (0x%x)\n", sp->predictor, sp->predictor);
	436	}
	437	if (sp->printdir)
	438	(*sp->printdir)(tif, fd, flags);
	439	}
	440
	441	int
	442	TIFFPredictorInit(TIFF* tif)
	443	{
	444	TIFFPredictorState* sp = PredictorState(tif);
	445
	446	/*
	447	* Merge codec-specific tag information and
	448	* override parent get/set field methods.
	449	*/
	450	_TIFFMergeFieldInfo(tif, predictFieldInfo, N(predictFieldInfo));
	451	sp->vgetparent = tif->tif_vgetfield;
	452	tif->tif_vgetfield = PredictorVGetField;/* hook for predictor tag */
	453	sp->vsetparent = tif->tif_vsetfield;
	454	tif->tif_vsetfield = PredictorVSetField;/* hook for predictor tag */
	455	sp->printdir = tif->tif_printdir;
	456	tif->tif_printdir = PredictorPrintDir; /* hook for predictor tag */
	457
	458	sp->setupdecode = tif->tif_setupdecode;
	459	tif->tif_setupdecode = PredictorSetupDecode;
	460	sp->setupencode = tif->tif_setupencode;
	461	tif->tif_setupencode = PredictorSetupEncode;
	462
	463	sp->predictor = 1; /* default value */
	464	sp->pfunc = NULL; /* no predictor routine */
	465	return (1);
	466	}