text: /* $Id: tif_predict.c,v 1.11.2.3 2009-01-23 15:57:18 fwarmerdam 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 horAcc32(TIFF*, tidata_t, tsize_t);
  static	void swabHorAcc16(TIFF*, tidata_t, tsize_t);
  static	void swabHorAcc32(TIFF*, tidata_t, tsize_t);
  static	void horDiff8(TIFF*, tidata_t, tsize_t);
  static	void horDiff16(TIFF*, tidata_t, tsize_t);
  static	void horDiff32(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
  			    && td->td_bitspersample != 32) {
  				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->decodepfunc = horAcc8; break;
  			case 16: sp->decodepfunc = horAcc16; break;
  			case 32: sp->decodepfunc = horAcc32; break;
  		}
  		/*
  		 * Override default decoding method with one that does the
  		 * predictor stuff.
  		 */
                  if( tif->tif_decoderow != PredictorDecodeRow )
                  {
                      sp->decoderow = tif->tif_decoderow;
                      tif->tif_decoderow = PredictorDecodeRow;
                      sp->decodestrip = tif->tif_decodestrip;
                      tif->tif_decodestrip = PredictorDecodeTile;
                      sp->decodetile = 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->decodepfunc == horAcc16) {
  				sp->decodepfunc = swabHorAcc16;
  				tif->tif_postdecode = _TIFFNoPostDecode;
  			} else if (sp->decodepfunc == horAcc32) {
  				sp->decodepfunc = swabHorAcc32;
  				tif->tif_postdecode = _TIFFNoPostDecode;
  			}
  		}
  	}
  
  	else if (sp->predictor == 3) {
  		sp->decodepfunc = fpAcc;
  		/*
  		 * Override default decoding method with one that does the
  		 * predictor stuff.
  		 */
                  if( tif->tif_decoderow != PredictorDecodeRow )
                  {
                      sp->decoderow = tif->tif_decoderow;
                      tif->tif_decoderow = PredictorDecodeRow;
                      sp->decodestrip = tif->tif_decodestrip;
                      tif->tif_decodestrip = PredictorDecodeTile;
                      sp->decodetile = 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->encodepfunc = horDiff8; break;
  			case 16: sp->encodepfunc = horDiff16; break;
  			case 32: sp->encodepfunc = horDiff32; break;
  		}
  		/*
  		 * Override default encoding method with one that does the
  		 * predictor stuff.
  		 */
                  if( tif->tif_encoderow != PredictorEncodeRow )
                  {
                      sp->encoderow = tif->tif_encoderow;
                      tif->tif_encoderow = PredictorEncodeRow;
                      sp->encodestrip = tif->tif_encodestrip;
                      tif->tif_encodestrip = PredictorEncodeTile;
                      sp->encodetile = tif->tif_encodetile;
                      tif->tif_encodetile = PredictorEncodeTile;
                  }
  	}
  	
  	else if (sp->predictor == 3) {
  		sp->encodepfunc = fpDiff;
  		/*
  		 * Override default encoding method with one that does the
  		 * predictor stuff.
  		 */
                  if( tif->tif_encoderow != PredictorEncodeRow )
                  {
                      sp->encoderow = tif->tif_encoderow;
                      tif->tif_encoderow = PredictorEncodeRow;
                      sp->encodestrip = tif->tif_encodestrip;
                      tif->tif_encodestrip = PredictorEncodeTile;
                      sp->encodetile = 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);
  	}
  }
  
  static void
  swabHorAcc32(TIFF* tif, tidata_t cp0, tsize_t cc)
  {
  	tsize_t stride = PredictorState(tif)->stride;
  	uint32* wp = (uint32*) cp0;
  	tsize_t wc = cc / 4;
  
  	if (wc > stride) {
  		TIFFSwabArrayOfLong(wp, wc);
  		wc -= stride;
  		do {
  			REPEAT4(stride, wp[stride] += wp[0]; wp++)
  			wc -= stride;
  		} while ((int32) wc > 0);
  	}
  }
  
  static void
  horAcc32(TIFF* tif, tidata_t cp0, tsize_t cc)
  {
  	tsize_t stride = PredictorState(tif)->stride;
  	uint32* wp = (uint32*) cp0;
  	tsize_t wc = cc / 4;
  
  	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;
  	}
  
  	_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->decoderow != NULL);
  	assert(sp->decodepfunc != NULL);
  
  	if ((*sp->decoderow)(tif, op0, occ0, s)) {
  		(*sp->decodepfunc)(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->decodetile != NULL);
  
  	if ((*sp->decodetile)(tif, op0, occ0, s)) {
  		tsize_t rowsize = sp->rowsize;
  		assert(rowsize > 0);
  		assert(sp->decodepfunc != NULL);
  		while ((long)occ0 > 0) {
  			(*sp->decodepfunc)(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);
  	}
  }
  
  static void
  horDiff32(TIFF* tif, tidata_t cp0, tsize_t cc)
  {
  	TIFFPredictorState* sp = PredictorState(tif);
  	tsize_t stride = sp->stride;
  	int32 *wp = (int32*) cp0;
  	tsize_t wc = cc/4;
  
  	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->encodepfunc != NULL);
  	assert(sp->encoderow != NULL);
  
  	/* XXX horizontal differencing alters user's data XXX */
  	(*sp->encodepfunc)(tif, bp, cc);
  	return (*sp->encoderow)(tif, bp, cc, s);
  }
  
  static int
  PredictorEncodeTile(TIFF* tif, tidata_t bp0, tsize_t cc0, tsample_t s)
  {
  	static const char module[] = "PredictorEncodeTile";
  	TIFFPredictorState *sp = PredictorState(tif);
          uint8 *working_copy;
  	tsize_t cc = cc0, rowsize;
  	unsigned char* bp;
          int result_code;
  
  	assert(sp != NULL);
  	assert(sp->encodepfunc != NULL);
  	assert(sp->encodetile != NULL);
  
          /* 
           * Do predictor manipulation in a working buffer to avoid altering
           * the callers buffer. http://trac.osgeo.org/gdal/ticket/1965
           */
          working_copy = (uint8*) _TIFFmalloc(cc0);
          if( working_copy == NULL )
          {
              TIFFErrorExt(tif->tif_clientdata, module, 
                           "Out of memory allocating %d byte temp buffer.",
                           cc0 );
              return 0;
          }
          memcpy( working_copy, bp0, cc0 );
          bp = working_copy;
  
  	rowsize = sp->rowsize;
  	assert(rowsize > 0);
  	assert((cc0%rowsize)==0);
  	while (cc > 0) {
  		(*sp->encodepfunc)(tif, bp, rowsize);
  		cc -= rowsize;
  		bp += rowsize;
  	}
  	result_code = (*sp->encodetile)(tif, working_copy, cc0, s);
  
          _TIFFfree( working_copy );
  
          return result_code;
  }
  
  #define	FIELD_PREDICTOR	(FIELD_CODEC+0)		/* XXX */
  
  static const TIFFFieldInfo predictFieldInfo[] = {
      { TIFFTAG_PREDICTOR,	 1, 1, TIFF_SHORT,	FIELD_PREDICTOR,
        FALSE,	FALSE,	"Predictor" },
  };
  
  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.
  	 */
  	if (!_TIFFMergeFieldInfo(tif, predictFieldInfo,
  				 TIFFArrayCount(predictFieldInfo))) {
  		TIFFErrorExt(tif->tif_clientdata, "TIFFPredictorInit",
  			     "Merging Predictor codec-specific tags failed");
  		return 0;
  	}
  
  	/*
  	 * Override parent get/set field methods.
  	 */
  	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->encodepfunc = NULL;			/* no predictor routine */
  	sp->decodepfunc = 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: */
  