tif_predict.c

奇趣公司比较新的qt/emd版本

/* $Id: tif_predict.c,v 1.11 2006/03/03 14:10:09 dron 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.
 */

/*
 * TIFF Library.
 *
 * Predictor Tag Support (used by multiple codecs).
 */
#include "tiffiop.h"
#include "tif_predict.h"

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

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

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

	TIFFPredictorState* sp = PredictorState(tif);
	TIFFDirectory* td = &tif->tif_dir;

	switch (sp->predictor)		/* no differencing */
	{
		case PREDICTOR_NONE:
			return 1;
		case PREDICTOR_HORIZONTAL:
			if (td->td_bitspersample != 8
			    && td->td_bitspersample != 16) {
				TIFFErrorExt(tif->tif_clientdata, module,
    "Horizontal differencing \"Predictor\" not supported with %d-bit samples",
					  td->td_bitspersample);
				return 0;
			}
			break;
		case PREDICTOR_FLOATINGPOINT:
			if (td->td_sampleformat != SAMPLEFORMAT_IEEEFP) {
				TIFFErrorExt(tif->tif_clientdata, module,
	"Floating point \"Predictor\" not supported with %d data format",
					  td->td_sampleformat);
				return 0;
			}
			break;
		default:
			TIFFErrorExt(tif->tif_clientdata, module,
				  "\"Predictor\" value %d not supported",
				  sp->predictor);
			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... */
		}
	}

	else if (sp->predictor == 3) {
		sp->pfunc = fpAcc;
		/*
		 * 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;
		/*
		 * The data should not be swapped outside of the floating
		 * point predictor, the accumulation routine should return
		 * byres in the native order.
		 */
		if (tif->tif_flags & TIFF_SWAB) {
			tif->tif_postdecode = _TIFFNoPostDecode;
		}
		/*
		 * Allocate buffer to keep the decoded bytes before
		 * rearranging in the ight order
		 */
	}

	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;
	}
	
	else if (sp->predictor == 3) {
		sp->pfunc = fpDiff;
		/*
		 * 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)
{
	tsize_t stride = PredictorState(tif)->stride;

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

static void
swabHorAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
{
	tsize_t stride = PredictorState(tif)->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)
{
	tsize_t 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);
	}
}

/*
 * Floating point predictor accumulation routine.
 */
static void
fpAcc(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 = cc;
	uint8 *cp = (uint8 *) cp0;
	uint8 *tmp = (uint8 *)_TIFFmalloc(cc);

	if (!tmp)
		return;

	while (count > stride) {
		REPEAT4(stride, cp[stride] += cp[0]; cp++)
		count -= stride;
	}