-
Notifications
You must be signed in to change notification settings - Fork 16
/
pts_lzw.c
1492 lines (1402 loc) · 41 KB
/
pts_lzw.c
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
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#define DUMMY \
set -ex; \
g++ -DNDEBUG=1 -O3 -ansi -pedantic \
-Wall -W -Wstrict-prototypes -Wtraditional -Wnested-externs -Winline \
-Wpointer-arith -Wbad-function-cast -Wcast-qual -Wmissing-prototypes \
-Wmissing-declarations pts_lzw.c -c; \
exit
/* pts_lzw.c -- a real, effective implementation of PostScript
* LanguageLevel2 and PDF /LZWEncode and /LZWDecode filters (same as the LZW
* compression used in TIFF raster image files)
*
* based on tif_lzw.c in libtiff-v3.4beta037 by Sam Leffler and Silicon Graphics.
* by pts@fazekas.hu at Sun Dec 30 15:04:19 CET 2001
* encoding and decoding works at Sun Dec 30 17:05:23 CET 2001
* modified for sam2p at Mon Mar 4 00:21:59 CET 2002
*
* Note that the LZW compression (but not uncompression) is patented by
* Unisys (patent number #4,558,302), so use this program at your own legal
* risk!
*
* Predictors and PostScript LanguageLevel3 filter options are not supported.
*
* Test: linux-2.2.8.tar.gz
* -- uncompressed: 58 388 480 bytes
* -- LZWEncode (lzw_codec.c): 26 518 397 bytes (uncompression OK)
* -- FlateEncode (almost gzip): 13 808 890 bytes (uncompression: zcat)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* Imp: check #ifdef _WINDOWS */
/* Dat: a strip is an interval of rows. Each strip -- probably except for the
* last -- has a same number of rows. Strips are useful for TIFF writers
* to better organize data in memory or disk.
*/
#ifdef __GNUC__
#ifndef __clang__
#ifdef __cplusplus
#pragma implementation
#endif
#endif
#endif
#if _MSC_VER > 1000
# undef __PROTOTYPES__
# define __PROTOTYPES__ 1
# pragma warning(disable: 4127) /* conditional expression is constant */
# pragma warning(disable: 4244) /* =' : conversion from 'int ' to 'unsigned char ', possible loss of data */
#endif
/* Original: /d1/sam/tiff/libtiff/RCS/tif_lzw.c,v 1.73 1997/08/29 21:45:54 sam 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.
*/
/**** pts ****/
#if OBJDEP
# warning PROVIDES: pts_lzw
#endif
#define LZW_SUPPORT 1
#if 0 /* conflicts with some system defs */
typedef unsigned short u_short;
typedef unsigned char u_char;
typedef unsigned long u_long;
#endif
#define TO_RDONLY 1
#define _TIFFmalloc malloc
#define _TIFFfree free
#define _TIFFmemset memset
#include <stdlib.h>
#include <string.h>
/*
* ``Library-private'' definitions.
*/
/*
* TIFF I/O Library Definitions.
*/
/*
* Tag Image File Format (TIFF)
*
* Based on Rev 6.0 from:
* Developer's Desk
* Aldus Corporation
* 411 First Ave. South
* Suite 200
* Seattle, WA 98104
* 206-622-5500
*/
#define TIFF_VERSION 42
/*
* NB: In the comments below,
* - items marked with a + are obsoleted by revision 5.0,
* - items marked with a ! are introduced in revision 6.0.
* - items marked with a % are introduced post revision 6.0.
* - items marked with a $ are obsoleted by revision 6.0.
*/
/* --- */
/*
* This define can be used in code that requires
* compilation-related definitions specific to a
* version or versions of the library. Runtime
* version checking should be done based on the
* string returned by TIFFGetVersion.
*/
#define TIFFLIB_VERSION 19970127 /* January 27, 1997 */
/*
* The following typedefs define the intrinsic size of
* data types used in the *exported* interfaces. These
* definitions depend on the proper definition of types
* in tiff.h. Note also that the varargs interface used
* to pass tag types and values uses the types defined in
* tiff.h directly.
*
* NB: ttag_t is unsigned int and not unsigned short because
* ANSI C requires that the type before the ellipsis be a
* promoted type (i.e. one of int, unsigned int, pointer,
* or double) and because we defined pseudo-tags that are
* outside the range of legal Aldus-assigned tags.
* NB: tsize_t is int32 and not uint32 because some functions
* return -1.
* NB: toff_t is not off_t for many reasons; TIFFs max out at
* 32-bit file offsets being the most important
*/
#ifndef NULL
#define NULL 0
#endif
typedef struct pts_lzw_state TIFF;
#include "pts_lzw.h"
/**** pts ****/
static int TIFFInitLZW(TIFF*);
static void TIFFError(char const*a, char const*b);
#if 0 /**** pts ****/
static void TIFFWarning(char const*a, char const*b, int c);
void TIFFWarning(char const*a, char const*b, int c) {
fprintf(stderr, "Warning: %s: ", a);
fprintf(stderr, b, c);
fprintf(stderr, "\n");
}
#endif
static int TIFFAppendTo(TIFF*, tidataval_t*, tsize_t); /* tif_write.h */
#if 0
static void TIFFReverseBits(unsigned char *, unsigned long);
#endif
#ifdef LZW_SUPPORT
/*
* TIFF Library.
* Rev 5.0 Lempel-Ziv & Welch Compression Support
*
* This code is derived from the compress program whose code is
* derived from software contributed to Berkeley by James A. Woods,
* derived from original work by Spencer Thomas and Joseph Orost.
*
* The original Berkeley copyright notice appears below in its entirety.
*/
#include <assert.h>
/* #include <stdio.h> */
/*
* Internal version of TIFFFlushData that can be
* called by ``encodestrip routines'' w/o concern
* for infinite recursion.
*/
static int
TIFFFlushData1(TIFF* tif)
{
if (tif->tif_rawcc > 0) {
#if 0
if (tif->tif_revbits_p)
TIFFReverseBits((unsigned char *)tif->tif_rawdata,
tif->tif_rawcc);
#endif
if (!TIFFAppendTo(tif,
/* isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip, */
tif->tif_rawdata, tif->tif_rawcc))
return (0);
tif->tif_rawcc = 0;
tif->tif_rawcp = tif->tif_rawdata;
}
return (1);
}
/*
* NB: The 5.0 spec describes a different algorithm than Aldus
* implements. Specifically, Aldus does code length transitions
* one code earlier than should be done (for real LZW).
* Earlier versions of this library implemented the correct
* LZW algorithm, but emitted codes in a bit order opposite
* to the TIFF spec. Thus, to maintain compatibility w/ Aldus
* we interpret MSB-LSB ordered codes to be images written w/
* old versions of this library, but otherwise adhere to the
* Aldus "off by one" algorithm.
*
* Future revisions to the TIFF spec are expected to "clarify this issue".
*/
#define LZW_COMPAT /* include backwards compatibility code */
/*
* Each strip of data is supposed to be terminated by a CODE_EOI.
* If the following #define is included, the decoder will also
* check for end-of-strip w/o seeing this code. This makes the
* library more robust, but also slower.
*/
#define LZW_CHECKEOS /* include checks for strips w/o EOI code */
#undef LZW_CHECKEOS /**** pts ****/
#define MAXCODE(n) ((1L<<(n))-1)
/*
* The TIFF spec specifies that encoded bit
* strings range from 9 to 12 bits.
*/
#define BITS_MIN 9 /* start with 9 bits */
#define BITS_MAX 12 /* max of 12 bit strings */
/* predefined codes */
#define CODE_CLEAR 256 /* code to clear string table */
#define CODE_EOI 257 /* end-of-information code */
#define CODE_FIRST 258 /* first free code entry */
#define CODE_MAX MAXCODE(BITS_MAX)
#define HSIZE 9001L /* 91% occupancy */
#define HSHIFT (13-8)
#ifdef LZW_COMPAT
/* NB: +1024 is for compatibility with old files */
#define CSIZE (MAXCODE(BITS_MAX)+1024L)
#else
#define CSIZE (MAXCODE(BITS_MAX)+1L)
#endif
/*
* State block for each open TIFF file using LZW
* compression/decompression. Note that the predictor
* state block must be first in this data structure.
*/
typedef struct {
#if 0 /****pts****/
TIFFPredictorState predict; /* predictor super class */
#endif
unsigned short nbits; /* # of bits/code */
unsigned short maxcode; /* maximum code for lzw_nbits */
unsigned short free_ent; /* next free entry in hash table */
long nextdata; /* next bits of i/o */
long nextbits; /* # of valid bits in lzw_nextdata */
} LZWBaseState;
#define lzw_nbits base.nbits
#define lzw_maxcode base.maxcode
#define lzw_free_ent base.free_ent
#define lzw_nextdata base.nextdata
#define lzw_nextbits base.nextbits
/*
* Decoding-specific state.
*/
typedef struct code_ent {
struct code_ent *next;
unsigned short length; /* string len, including this token */
unsigned char value; /* data value */
unsigned char firstchar; /* first token of string */
} code_t;
typedef int (*decodeFunc)(TIFF*, tidataval_t*, tsize_t);
typedef struct {
LZWBaseState base;
long dec_nbitsmask; /* lzw_nbits 1 bits, right adjusted */
long dec_restart; /* restart count */
#ifdef LZW_CHECKEOS
long dec_bitsleft; /* available bits in raw data */
#endif
decodeFunc dec_decode; /* regular or backwards compatible */
code_t* dec_codep; /* current recognized code */
code_t* dec_oldcodep; /* previously recognized code */
code_t* dec_free_entp; /* next free entry */
code_t* dec_maxcodep; /* max available entry */
code_t* dec_codetab; /* kept separate for small machines */
} LZWDecodeState;
/*
* Encoding-specific state.
*/
typedef unsigned short hcode_t; /* codes fit in 16 bits */
typedef struct {
long hash;
hcode_t code;
} hash_t;
typedef struct {
LZWBaseState base;
int enc_oldcode; /* last code encountered */
long enc_checkpoint; /* point at which to clear table */
#define CHECK_GAP 10000 /* enc_ratio check interval */
long enc_ratio; /* current compression ratio */
long enc_incount; /* (input) data bytes encoded */
long enc_outcount; /* encoded (output) bytes */
tidataval_t* enc_rawlimit; /* bound on tif_rawdata buffer */
hash_t* enc_hashtab; /* kept separate for small machines */
} LZWEncodeState;
#define LZWState(tif) ((LZWBaseState*) (void*) (tif)->tif_data)
#define DecoderState(tif) ((LZWDecodeState*)(void*) LZWState(tif))
#define EncoderState(tif) ((LZWEncodeState*)(void*) LZWState(tif))
/* ^^^ Dat: (void*) -> suppress gcc warning from -Wcast-align */
static void cl_hash(LZWEncodeState*);
#if 0 /**** pts ****/ /* LZW decoder is not needed */
static int LZWDecode(TIFF*, tidataval_t*, tsize_t);
#ifdef LZW_COMPAT
static int LZWDecodeCompat(TIFF*, tidataval_t*, tsize_t);
#endif
/*
* LZW Decoder.
*/
#ifdef LZW_CHECKEOS
/*
* This check shouldn't be necessary because each
* strip is suppose to be terminated with CODE_EOI.
*/
#define NextCode(_tif, _sp, _bp, _code, _get) { \
if ((_sp)->dec_bitsleft < nbits) { \
TIFFWarning(_tif->tif_name, \
"LZWDecode: Strip %d not terminated with EOI code", \
/*_tif->tif_curstrip*/ 0); \
_code = CODE_EOI; \
} else { \
_get(_sp,_bp,_code); \
(_sp)->dec_bitsleft -= nbits; \
} \
}
#else
#define NextCode(tif, sp, bp, code, get) get(sp, bp, code)
#endif
static int
LZWSetupDecode(TIFF* tif)
{
LZWDecodeState* sp = DecoderState(tif);
static const char module[] = " LZWSetupDecode";
int code;
assert(sp != NULL);
if (sp->dec_codetab == NULL) {
sp->dec_codetab = (code_t*)_TIFFmalloc(CSIZE*sizeof (code_t));
if (sp->dec_codetab == NULL) {
TIFFError(module, "No space for LZW code table");
return (0);
}
/*
* Pre-load the table.
*/
for (code = 255; code >= 0; code--) {
sp->dec_codetab[code].value = code;
sp->dec_codetab[code].firstchar = code;
sp->dec_codetab[code].length = 1;
sp->dec_codetab[code].next = NULL;
}
}
return (1);
}
/*
* Setup state for decoding a strip.
*/
static int
LZWPreDecode(TIFF* tif)
{
LZWDecodeState *sp = DecoderState(tif);
assert(sp != NULL);
/*
* Check for old bit-reversed codes.
*/
if (tif->tif_rawdata[0] == 0 && (tif->tif_rawdata[1] & 0x1)) {
#ifdef LZW_COMPAT
if (!sp->dec_decode) {
TIFFWarning(tif->tif_name,
"Old-style LZW codes, convert file %d", 0);
#if 0 /**** pts ****/
/*
* Override default decoding methods with
* ones that deal with the old coding.
* Otherwise the predictor versions set
* above will call the compatibility routines
* through the dec_decode method.
*/
tif->tif_decoderow = LZWDecodeCompat;
tif->tif_decodestrip = LZWDecodeCompat;
tif->tif_decodetile = LZWDecodeCompat;
/*
* If doing horizontal differencing, must
* re-setup the predictor logic since we
* switched the basic decoder methods...
*/
(*tif->tif_setupdecode)(tif);
#endif
LZWSetupDecode(tif);
sp->dec_decode = LZWDecodeCompat;
}
sp->lzw_maxcode = MAXCODE(BITS_MIN);
#else /* !LZW_COMPAT */
if (!sp->dec_decode) {
TIFFError(tif->tif_name,
"Old-style LZW codes not supported");
sp->dec_decode = LZWDecode;
}
return (0);
#endif/* !LZW_COMPAT */
} else {
sp->lzw_maxcode = MAXCODE(BITS_MIN)-1;
sp->dec_decode = LZWDecode;
}
sp->lzw_nbits = BITS_MIN;
sp->lzw_nextbits = 0;
sp->lzw_nextdata = 0;
sp->dec_restart = 0;
sp->dec_nbitsmask = MAXCODE(BITS_MIN);
#ifdef LZW_CHECKEOS
sp->dec_bitsleft = tif->tif_rawcc << 3;
#endif
sp->dec_free_entp = sp->dec_codetab + CODE_FIRST;
/*
* Zero entries that are not yet filled in. We do
* this to guard against bogus input data that causes
* us to index into undefined entries. If you can
* come up with a way to safely bounds-check input codes
* while decoding then you can remove this operation.
*/
_TIFFmemset(sp->dec_free_entp, 0, (CSIZE-CODE_FIRST)*sizeof (code_t));
sp->dec_oldcodep = &sp->dec_codetab[-1];
sp->dec_maxcodep = &sp->dec_codetab[sp->dec_nbitsmask-1];
return (1);
}
/*
* Decode a "hunk of data".
*/
#define GetNextCode(sp, bp, code) { \
nextdata = (nextdata<<8) | *(bp)++; \
nextbits += 8; \
if (nextbits < nbits) { \
nextdata = (nextdata<<8) | *(bp)++; \
nextbits += 8; \
} \
code = (hcode_t)((nextdata >> (nextbits-nbits)) & nbitsmask); \
nextbits -= nbits; \
}
static void
codeLoop(TIFF* tif)
{
TIFFError(tif->tif_name,
"LZWDecode: Bogus encoding, loop in the code table; scanline %d"
/*,tif->tif_row*/);
}
static int
LZWDecode(TIFF* tif, tidataval_t* op0, tsize_t occ0)
{
LZWDecodeState *sp = DecoderState(tif);
char *op = (char*) op0;
long occ = (long) occ0;
char *tp;
unsigned char *bp;
hcode_t code;
int len;
long nbits, nextbits, nextdata, nbitsmask;
code_t *codep, *free_entp, *maxcodep, *oldcodep;
assert(sp != NULL);
/*
* Restart interrupted output operation.
*/
if (sp->dec_restart) {
long residue;
codep = sp->dec_codep;
residue = codep->length - sp->dec_restart;
if (residue > occ) {
/*
* Residue from previous decode is sufficient
* to satisfy decode request. Skip to the
* start of the decoded string, place decoded
* values in the output buffer, and return.
*/
sp->dec_restart += occ;
do {
codep = codep->next;
} while (--residue > occ && codep);
if (codep) {
tp = op + occ;
do {
*--tp = codep->value;
codep = codep->next;
} while (--occ && codep);
}
return occ0-occ;
}
/*
* Residue satisfies only part of the decode request.
*/
op += residue, occ -= residue;
tp = op;
do {
int t;
--tp;
t = codep->value;
codep = codep->next;
*tp = t;
} while (--residue && codep);
sp->dec_restart = 0;
}
bp = (unsigned char *)tif->tif_rawcp; /* reading from here */
nbits = sp->lzw_nbits;
nextdata = sp->lzw_nextdata;
nextbits = sp->lzw_nextbits;
nbitsmask = sp->dec_nbitsmask;
oldcodep = sp->dec_oldcodep;
free_entp = sp->dec_free_entp;
maxcodep = sp->dec_maxcodep;
while (occ > 0 && bp<tif->tif_rawend /**** pts ****/) {
NextCode(tif, sp, bp, code, GetNextCode);
#if 0
if (bp>tif->tif_rawend) fprintf(stderr, "over %d\n", tif->tif_rawend-bp);
assert(bp<=tif->tif_rawend);
#endif
if (code == CODE_EOI)
break;
if (code == CODE_CLEAR) {
free_entp = sp->dec_codetab + CODE_FIRST;
nbits = BITS_MIN;
nbitsmask = MAXCODE(BITS_MIN);
maxcodep = sp->dec_codetab + nbitsmask-1;
#if 1 /**** pts ****/
NextCode(tif, sp, bp, code, GetNextCode);
if (code == CODE_EOI)
break;
*op++ = code, occ--;
oldcodep = sp->dec_codetab + code; /* ! */
#endif
continue;
}
codep = sp->dec_codetab + code;
/*
* Add the new entry to the code table.
*/
assert(&sp->dec_codetab[0] <= free_entp && free_entp < &sp->dec_codetab[CSIZE]);
free_entp->next = oldcodep;
free_entp->firstchar = free_entp->next->firstchar;
free_entp->length = free_entp->next->length+1;
free_entp->value = (codep < free_entp) ?
codep->firstchar : free_entp->firstchar;
if (++free_entp > maxcodep) {
if (++nbits > BITS_MAX) /* should not happen */
nbits = BITS_MAX;
nbitsmask = MAXCODE(nbits);
maxcodep = sp->dec_codetab + nbitsmask-1;
}
oldcodep = codep;
if (code >= 256) {
/*
* Code maps to a string, copy string
* value to output (written in reverse).
*/
if (codep->length > occ) {
/*
* String is too long for decode buffer,
* locate portion that will fit, copy to
* the decode buffer, and setup restart
* logic for the next decoding call.
*/
sp->dec_codep = codep;
do {
codep = codep->next;
} while (codep && codep->length > occ);
if (codep) {
sp->dec_restart = occ;
tp = op + occ;
do {
*--tp = codep->value;
codep = codep->next;
} while (--occ && codep);
if (codep) {
codeLoop(tif);
return -1;
}
}
break;
}
len = codep->length;
tp = op + len;
do {
int t;
--tp;
t = codep->value;
codep = codep->next;
*tp = t;
} while (codep && tp > op);
if (codep) {
codeLoop(tif);
return -1;
/* break; */
}
op += len, occ -= len;
} else
*op++ = code, occ--;
}
tif->tif_rawcp = (tidataval_t*) bp;
sp->lzw_nbits = (unsigned short) nbits;
sp->lzw_nextdata = nextdata;
sp->lzw_nextbits = nextbits;
sp->dec_nbitsmask = nbitsmask;
sp->dec_oldcodep = oldcodep;
sp->dec_free_entp = free_entp;
sp->dec_maxcodep = maxcodep;
#if 0 /**** pts ****/
if (occ > 0) {
TIFFError(tif->tif_name,
"LZWDecode: Not enough data at scanline %d (short %d bytes)"
/*,tif->tif_row, occ*/);
return (0);
}
#endif
return occ0-occ;
}
#ifdef LZW_COMPAT
/*
* Decode a "hunk of data" for old images.
*/
#define GetNextCodeCompat(sp, bp, code) { \
nextdata |= (unsigned long) *(bp)++ << nextbits; \
nextbits += 8; \
if (nextbits < nbits) { \
nextdata |= (unsigned long) *(bp)++ << nextbits; \
nextbits += 8; \
} \
code = (hcode_t)(nextdata & nbitsmask); \
nextdata >>= nbits; \
nextbits -= nbits; \
}
static int
LZWDecodeCompat(TIFF* tif, tidataval_t* op0, tsize_t occ0)
{
LZWDecodeState *sp = DecoderState(tif);
char *op = (char*) op0;
long occ = (long) occ0;
char *tp;
unsigned char *bp;
int code, nbits;
long nextbits, nextdata, nbitsmask;
code_t *codep, *free_entp, *maxcodep, *oldcodep;
assert(0);
assert(sp != NULL);
/*
* Restart interrupted output operation.
*/
if (sp->dec_restart) {
long residue;
codep = sp->dec_codep;
residue = codep->length - sp->dec_restart;
if (residue > occ) {
/*
* Residue from previous decode is sufficient
* to satisfy decode request. Skip to the
* start of the decoded string, place decoded
* values in the output buffer, and return.
*/
sp->dec_restart += occ;
do {
codep = codep->next;
} while (--residue > occ);
tp = op + occ;
do {
*--tp = codep->value;
codep = codep->next;
} while (--occ);
return occ0-occ;
}
/*
* Residue satisfies only part of the decode request.
*/
op += residue, occ -= residue;
tp = op;
do {
*--tp = codep->value;
codep = codep->next;
} while (--residue);
sp->dec_restart = 0;
}
bp = (unsigned char *)tif->tif_rawcp;
nbits = sp->lzw_nbits;
nextdata = sp->lzw_nextdata;
nextbits = sp->lzw_nextbits;
nbitsmask = sp->dec_nbitsmask;
oldcodep = sp->dec_oldcodep;
free_entp = sp->dec_free_entp;
maxcodep = sp->dec_maxcodep;
while (occ > 0 && bp<tif->tif_rawend) {
NextCode(tif, sp, bp, code, GetNextCodeCompat);
if (code == CODE_EOI)
break;
if (code == CODE_CLEAR) {
free_entp = sp->dec_codetab + CODE_FIRST;
nbits = BITS_MIN;
nbitsmask = MAXCODE(BITS_MIN);
maxcodep = sp->dec_codetab + nbitsmask;
NextCode(tif, sp, bp, code, GetNextCodeCompat);
if (code == CODE_EOI)
break;
*op++ = code, occ--;
oldcodep = sp->dec_codetab + code;
continue;
}
codep = sp->dec_codetab + code;
/*
* Add the new entry to the code table.
*/
assert(&sp->dec_codetab[0] <= free_entp && free_entp < &sp->dec_codetab[CSIZE]);
free_entp->next = oldcodep;
free_entp->firstchar = free_entp->next->firstchar;
free_entp->length = free_entp->next->length+1;
free_entp->value = (codep < free_entp) ?
codep->firstchar : free_entp->firstchar;
if (++free_entp > maxcodep) {
if (++nbits > BITS_MAX) /* should not happen */
nbits = BITS_MAX;
nbitsmask = MAXCODE(nbits);
maxcodep = sp->dec_codetab + nbitsmask;
}
oldcodep = codep;
if (code >= 256) {
/*
* Code maps to a string, copy string
* value to output (written in reverse).
*/
if (codep->length > occ) {
/*
* String is too long for decode buffer,
* locate portion that will fit, copy to
* the decode buffer, and setup restart
* logic for the next decoding call.
*/
sp->dec_codep = codep;
do {
codep = codep->next;
} while (codep->length > occ);
sp->dec_restart = occ;
tp = op + occ;
do {
*--tp = codep->value;
codep = codep->next;
} while (--occ);
break;
}
op += codep->length, occ -= codep->length;
tp = op;
do {
*--tp = codep->value;
} while (0!=(codep = codep->next));
} else
*op++ = code, occ--;
}
tif->tif_rawcp = (tidataval_t*) bp;
sp->lzw_nbits = nbits;
sp->lzw_nextdata = nextdata;
sp->lzw_nextbits = nextbits;
sp->dec_nbitsmask = nbitsmask;
sp->dec_oldcodep = oldcodep;
sp->dec_free_entp = free_entp;
sp->dec_maxcodep = maxcodep;
#if 0 /**** pts ****/
if (occ > 0) {
TIFFError(tif->tif_name,
"LZWDecodeCompat: Not enough data at scanline %d (short %d bytes)"
/*,tif->tif_row, occ*/);
return (0);
}
#endif
return occ0-occ;
}
#endif /* LZW_COMPAT */
#endif /**** pts ****/
/* --- */
/*
* LZW Encoding.
*/
static int
LZWSetupEncode(TIFF* tif)
{
LZWEncodeState* sp = EncoderState(tif);
static const char module[] = "LZWSetupEncode";
assert(sp != NULL);
sp->enc_hashtab = (hash_t*) _TIFFmalloc(HSIZE*sizeof (hash_t));
if (sp->enc_hashtab == NULL) {
TIFFError(module, "No space for LZW hash table");
return (0);
}
return (1);
}
/*
* Reset encoding state at the start of a strip.
*/
static int
LZWPreEncode(TIFF* tif)
{
LZWEncodeState *sp = EncoderState(tif);
assert(sp != NULL);
sp->lzw_nbits = BITS_MIN;
sp->lzw_maxcode = MAXCODE(BITS_MIN);
sp->lzw_free_ent = CODE_FIRST;
sp->lzw_nextbits = 0;
sp->lzw_nextdata = 0;
sp->enc_checkpoint = CHECK_GAP;
sp->enc_ratio = 0;
sp->enc_incount = 0;
sp->enc_outcount = 0;
/*
* The 4 here insures there is space for 2 max-sized
* codes in LZWEncode and LZWPostDecode.
*/
sp->enc_rawlimit = tif->tif_rawdata + tif->tif_rawdatasize-1 - 4;
cl_hash(sp); /* clear hash table */
sp->enc_oldcode = (hcode_t) -1; /* generates CODE_CLEAR in LZWEncode */
return (1);
}
#define CALCRATIO(sp, rat) { \
if (incount > 0x007fffff) { /* NB: shift will overflow */\
rat = outcount >> 8; \
rat = (rat == 0 ? 0x7fffffff : incount/rat); \
} else \
rat = (incount<<8) / outcount; \
}
#define PutNextCode(op, c) { \
nextdata = (nextdata << nbits) | c; \
nextbits += nbits; \
*op++ = (unsigned char)(nextdata >> (nextbits-8)); \
nextbits -= 8; \
if (nextbits >= 8) { \
*op++ = (unsigned char)(nextdata >> (nextbits-8)); \
nextbits -= 8; \
} \
outcount += nbits; \
}
/*
* Encode a chunk of pixels.
*
* Uses an open addressing double hashing (no chaining) on the
* prefix code/next character combination. We do a variant of
* Knuth's algorithm D (vol. 3, sec. 6.4) along with G. Knott's
* relatively-prime secondary probe. Here, the modular division
* first probe is gives way to a faster exclusive-or manipulation.
* Also do block compression with an adaptive reset, whereby the
* code table is cleared when the compression ratio decreases,
* but after the table fills. The variable-length output codes
* are re-sized at this point, and a CODE_CLEAR is generated
* for the decoder.
*/
static int
LZWEncode(TIFF* tif, tidataval_t* bp, tsize_t cc)
{
register LZWEncodeState *sp = EncoderState(tif);
register long fcode;
register hash_t *hp;
register int h, c;
hcode_t ent;
long disp;
long incount, outcount, checkpoint;
long nextdata, nextbits;
int free_ent, maxcode, nbits;
tidataval_t* op, *limit;
if (sp == NULL)
return (0);
/*
* Load local state.
*/
incount = sp->enc_incount;
outcount = sp->enc_outcount;
checkpoint = sp->enc_checkpoint;
nextdata = sp->lzw_nextdata;
nextbits = sp->lzw_nextbits;
free_ent = sp->lzw_free_ent;
maxcode = sp->lzw_maxcode;
nbits = sp->lzw_nbits;
op = tif->tif_rawcp;
limit = sp->enc_rawlimit;
ent = sp->enc_oldcode;
if (ent == (hcode_t) -1 && cc > 0) {
/*
* NB: This is safe because it can only happen
* at the start of a strip where we know there
* is space in the data buffer.
*/
PutNextCode(op, CODE_CLEAR);
ent = *bp++; cc--; incount++;
}
while (cc > 0) {
c = *bp++; cc--; incount++;
fcode = ((long)c << BITS_MAX) + ent;
h = (c << HSHIFT) ^ ent; /* xor hashing */
#ifdef _WINDOWS /* ?? */
/*
* Check hash index for an overflow.
*/
if (h >= HSIZE)
h -= HSIZE;
#endif
hp = &sp->enc_hashtab[h];
if (hp->hash == fcode) {
ent = hp->code;
continue;
}
if (hp->hash >= 0) {
/*
* Primary hash failed, check secondary hash.
*/
disp = HSIZE - h;
if (h == 0)
disp = 1;
do {
/*
* Avoid pointer arithmetic 'cuz of
* wraparound problems with segments.
*/
if ((h -= disp) < 0)
h += HSIZE;
hp = &sp->enc_hashtab[h];