tif_predict.c

奇趣公司比较新的qt/emd版本

	_TIFFmemcpy(tmp, cp0, cc);
	cp = (uint8 *) cp0;
	for (count = 0; count < wc; count++) {
		uint32 byte;
		for (byte = 0; byte < bps; byte++) {
#if WORDS_BIGENDIAN
			cp[bps * count + byte] = tmp[byte * wc + count];
#else
			cp[bps * count + byte] =
				tmp[(bps - byte - 1) * wc + count];
#endif
		}
	}
	_TIFFfree(tmp);
}

/*
 * 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);
	tsize_t 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);
	tsize_t 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);
	}
}

/*
 * Floating point predictor differencing routine.
 */
static void
fpDiff(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	tsize_t stride = PredictorState(tif)->stride;
	uint32 bps = tif->tif_dir.td_bitspersample / 8;
	tsize_t wc = cc / bps;
	tsize_t count;
	uint8 *cp = (uint8 *) cp0;
	uint8 *tmp = (uint8 *)_TIFFmalloc(cc);

	if (!tmp)
		return;

	_TIFFmemcpy(tmp, cp0, cc);
	for (count = 0; count < wc; count++) {
		uint32 byte;
		for (byte = 0; byte < bps; byte++) {
#if WORDS_BIGENDIAN
			cp[byte * wc + count] =	tmp[bps * count + byte];
#else
			cp[(bps - byte - 1) * wc + count] =
				tmp[bps * count + byte];
#endif
		}
	}
	_TIFFfree(tmp);

	cp = (uint8 *) cp0;
	cp += cc - stride - 1;
	for (count = cc; count > stride; count -= stride)
		REPEAT4(stride, cp[stride] -= cp[0]; cp--)
}

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;
	unsigned 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);

	assert(sp != NULL);
	assert(sp->vsetparent != NULL);

	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);

	assert(sp != NULL);
	assert(sp->vgetparent != NULL);

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

static void
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;
		case 3: fprintf(fd, "floating point predictor "); 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);

	assert(sp != 0);

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

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

	assert(sp != 0);

	tif->tif_tagmethods.vgetfield = sp->vgetparent;
	tif->tif_tagmethods.vsetfield = sp->vsetparent;
	tif->tif_tagmethods.printdir = sp->printdir;
	tif->tif_setupdecode = sp->setupdecode;
	tif->tif_setupencode = sp->setupencode;

	return 1;
}

/* vim: set ts=8 sts=8 sw=8 noet: */