summaryrefslogtreecommitdiff
path: root/plugins/FreeImage/Source/LibTIFF/tif_predict.c
blob: 7f7dc636bebad2b9ad4005a17bdc7caf87ab955e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
/* $Id: tif_predict.c,v 1.37 2011/04/10 17:14:09 drolon 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: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 8
 * fill-column: 78
 * End:
 */