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3cf8495776adc9a320d62bb42e0e4518ebd69dec
[reactos.git] / reactos / dll / 3rdparty / libtiff / tif_lzw.c
1 /* $Id: tif_lzw.c,v 1.52 2016-09-04 21:32:56 erouault Exp $ */
2
3 /*
4 * Copyright (c) 1988-1997 Sam Leffler
5 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
6 *
7 * Permission to use, copy, modify, distribute, and sell this software and
8 * its documentation for any purpose is hereby granted without fee, provided
9 * that (i) the above copyright notices and this permission notice appear in
10 * all copies of the software and related documentation, and (ii) the names of
11 * Sam Leffler and Silicon Graphics may not be used in any advertising or
12 * publicity relating to the software without the specific, prior written
13 * permission of Sam Leffler and Silicon Graphics.
14 *
15 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
17 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
20 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
21 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
22 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
23 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
24 * OF THIS SOFTWARE.
25 */
26
27 #include <precomp.h>
28
29 #ifdef LZW_SUPPORT
30 /*
31 * TIFF Library.
32 * Rev 5.0 Lempel-Ziv & Welch Compression Support
33 *
34 * This code is derived from the compress program whose code is
35 * derived from software contributed to Berkeley by James A. Woods,
36 * derived from original work by Spencer Thomas and Joseph Orost.
37 *
38 * The original Berkeley copyright notice appears below in its entirety.
39 */
40 #include "tif_predict.h"
41
42 #include <stdio.h>
43
44 /*
45 * NB: The 5.0 spec describes a different algorithm than Aldus
46 * implements. Specifically, Aldus does code length transitions
47 * one code earlier than should be done (for real LZW).
48 * Earlier versions of this library implemented the correct
49 * LZW algorithm, but emitted codes in a bit order opposite
50 * to the TIFF spec. Thus, to maintain compatibility w/ Aldus
51 * we interpret MSB-LSB ordered codes to be images written w/
52 * old versions of this library, but otherwise adhere to the
53 * Aldus "off by one" algorithm.
54 *
55 * Future revisions to the TIFF spec are expected to "clarify this issue".
56 */
57 #define LZW_COMPAT /* include backwards compatibility code */
58 /*
59 * Each strip of data is supposed to be terminated by a CODE_EOI.
60 * If the following #define is included, the decoder will also
61 * check for end-of-strip w/o seeing this code. This makes the
62 * library more robust, but also slower.
63 */
64 #define LZW_CHECKEOS /* include checks for strips w/o EOI code */
65
66 #define MAXCODE(n) ((1L<<(n))-1)
67 /*
68 * The TIFF spec specifies that encoded bit
69 * strings range from 9 to 12 bits.
70 */
71 #define BITS_MIN 9 /* start with 9 bits */
72 #define BITS_MAX 12 /* max of 12 bit strings */
73 /* predefined codes */
74 #define CODE_CLEAR 256 /* code to clear string table */
75 #define CODE_EOI 257 /* end-of-information code */
76 #define CODE_FIRST 258 /* first free code entry */
77 #define CODE_MAX MAXCODE(BITS_MAX)
78 #define HSIZE 9001L /* 91% occupancy */
79 #define HSHIFT (13-8)
80 #ifdef LZW_COMPAT
81 /* NB: +1024 is for compatibility with old files */
82 #define CSIZE (MAXCODE(BITS_MAX)+1024L)
83 #else
84 #define CSIZE (MAXCODE(BITS_MAX)+1L)
85 #endif
86
87 /*
88 * State block for each open TIFF file using LZW
89 * compression/decompression. Note that the predictor
90 * state block must be first in this data structure.
91 */
92 typedef struct {
93 TIFFPredictorState predict; /* predictor super class */
94
95 unsigned short nbits; /* # of bits/code */
96 unsigned short maxcode; /* maximum code for lzw_nbits */
97 unsigned short free_ent; /* next free entry in hash table */
98 unsigned long nextdata; /* next bits of i/o */
99 long nextbits; /* # of valid bits in lzw_nextdata */
100
101 int rw_mode; /* preserve rw_mode from init */
102 } LZWBaseState;
103
104 #define lzw_nbits base.nbits
105 #define lzw_maxcode base.maxcode
106 #define lzw_free_ent base.free_ent
107 #define lzw_nextdata base.nextdata
108 #define lzw_nextbits base.nextbits
109
110 /*
111 * Encoding-specific state.
112 */
113 typedef uint16 hcode_t; /* codes fit in 16 bits */
114 typedef struct {
115 long hash;
116 hcode_t code;
117 } hash_t;
118
119 /*
120 * Decoding-specific state.
121 */
122 typedef struct code_ent {
123 struct code_ent *next;
124 unsigned short length; /* string len, including this token */
125 unsigned char value; /* data value */
126 unsigned char firstchar; /* first token of string */
127 } code_t;
128
129 typedef int (*decodeFunc)(TIFF*, uint8*, tmsize_t, uint16);
130
131 typedef struct {
132 LZWBaseState base;
133
134 /* Decoding specific data */
135 long dec_nbitsmask; /* lzw_nbits 1 bits, right adjusted */
136 long dec_restart; /* restart count */
137 #ifdef LZW_CHECKEOS
138 uint64 dec_bitsleft; /* available bits in raw data */
139 #endif
140 decodeFunc dec_decode; /* regular or backwards compatible */
141 code_t* dec_codep; /* current recognized code */
142 code_t* dec_oldcodep; /* previously recognized code */
143 code_t* dec_free_entp; /* next free entry */
144 code_t* dec_maxcodep; /* max available entry */
145 code_t* dec_codetab; /* kept separate for small machines */
146
147 /* Encoding specific data */
148 int enc_oldcode; /* last code encountered */
149 long enc_checkpoint; /* point at which to clear table */
150 #define CHECK_GAP 10000 /* enc_ratio check interval */
151 long enc_ratio; /* current compression ratio */
152 long enc_incount; /* (input) data bytes encoded */
153 long enc_outcount; /* encoded (output) bytes */
154 uint8* enc_rawlimit; /* bound on tif_rawdata buffer */
155 hash_t* enc_hashtab; /* kept separate for small machines */
156 } LZWCodecState;
157
158 #define LZWState(tif) ((LZWBaseState*) (tif)->tif_data)
159 #define DecoderState(tif) ((LZWCodecState*) LZWState(tif))
160 #define EncoderState(tif) ((LZWCodecState*) LZWState(tif))
161
162 static int LZWDecode(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s);
163 #ifdef LZW_COMPAT
164 static int LZWDecodeCompat(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s);
165 #endif
166 static void cl_hash(LZWCodecState*);
167
168 /*
169 * LZW Decoder.
170 */
171
172 #ifdef LZW_CHECKEOS
173 /*
174 * This check shouldn't be necessary because each
175 * strip is suppose to be terminated with CODE_EOI.
176 */
177 #define NextCode(_tif, _sp, _bp, _code, _get) { \
178 if ((_sp)->dec_bitsleft < (uint64)nbits) { \
179 TIFFWarningExt(_tif->tif_clientdata, module, \
180 "LZWDecode: Strip %d not terminated with EOI code", \
181 _tif->tif_curstrip); \
182 _code = CODE_EOI; \
183 } else { \
184 _get(_sp,_bp,_code); \
185 (_sp)->dec_bitsleft -= nbits; \
186 } \
187 }
188 #else
189 #define NextCode(tif, sp, bp, code, get) get(sp, bp, code)
190 #endif
191
192 static int
193 LZWFixupTags(TIFF* tif)
194 {
195 (void) tif;
196 return (1);
197 }
198
199 static int
200 LZWSetupDecode(TIFF* tif)
201 {
202 static const char module[] = "LZWSetupDecode";
203 LZWCodecState* sp = DecoderState(tif);
204 int code;
205
206 if( sp == NULL )
207 {
208 /*
209 * Allocate state block so tag methods have storage to record
210 * values.
211 */
212 tif->tif_data = (uint8*) _TIFFmalloc(sizeof(LZWCodecState));
213 if (tif->tif_data == NULL)
214 {
215 TIFFErrorExt(tif->tif_clientdata, module, "No space for LZW state block");
216 return (0);
217 }
218
219 DecoderState(tif)->dec_codetab = NULL;
220 DecoderState(tif)->dec_decode = NULL;
221
222 /*
223 * Setup predictor setup.
224 */
225 (void) TIFFPredictorInit(tif);
226
227 sp = DecoderState(tif);
228 }
229
230 assert(sp != NULL);
231
232 if (sp->dec_codetab == NULL) {
233 sp->dec_codetab = (code_t*)_TIFFmalloc(CSIZE*sizeof (code_t));
234 if (sp->dec_codetab == NULL) {
235 TIFFErrorExt(tif->tif_clientdata, module,
236 "No space for LZW code table");
237 return (0);
238 }
239 /*
240 * Pre-load the table.
241 */
242 code = 255;
243 do {
244 sp->dec_codetab[code].value = (unsigned char)code;
245 sp->dec_codetab[code].firstchar = (unsigned char)code;
246 sp->dec_codetab[code].length = 1;
247 sp->dec_codetab[code].next = NULL;
248 } while (code--);
249 /*
250 * Zero-out the unused entries
251 */
252 _TIFFmemset(&sp->dec_codetab[CODE_CLEAR], 0,
253 (CODE_FIRST - CODE_CLEAR) * sizeof (code_t));
254 }
255 return (1);
256 }
257
258 /*
259 * Setup state for decoding a strip.
260 */
261 static int
262 LZWPreDecode(TIFF* tif, uint16 s)
263 {
264 static const char module[] = "LZWPreDecode";
265 LZWCodecState *sp = DecoderState(tif);
266
267 (void) s;
268 assert(sp != NULL);
269 if( sp->dec_codetab == NULL )
270 {
271 tif->tif_setupdecode( tif );
272 if( sp->dec_codetab == NULL )
273 return (0);
274 }
275
276 /*
277 * Check for old bit-reversed codes.
278 */
279 if (tif->tif_rawdata[0] == 0 && (tif->tif_rawdata[1] & 0x1)) {
280 #ifdef LZW_COMPAT
281 if (!sp->dec_decode) {
282 TIFFWarningExt(tif->tif_clientdata, module,
283 "Old-style LZW codes, convert file");
284 /*
285 * Override default decoding methods with
286 * ones that deal with the old coding.
287 * Otherwise the predictor versions set
288 * above will call the compatibility routines
289 * through the dec_decode method.
290 */
291 tif->tif_decoderow = LZWDecodeCompat;
292 tif->tif_decodestrip = LZWDecodeCompat;
293 tif->tif_decodetile = LZWDecodeCompat;
294 /*
295 * If doing horizontal differencing, must
296 * re-setup the predictor logic since we
297 * switched the basic decoder methods...
298 */
299 (*tif->tif_setupdecode)(tif);
300 sp->dec_decode = LZWDecodeCompat;
301 }
302 sp->lzw_maxcode = MAXCODE(BITS_MIN);
303 #else /* !LZW_COMPAT */
304 if (!sp->dec_decode) {
305 TIFFErrorExt(tif->tif_clientdata, module,
306 "Old-style LZW codes not supported");
307 sp->dec_decode = LZWDecode;
308 }
309 return (0);
310 #endif/* !LZW_COMPAT */
311 } else {
312 sp->lzw_maxcode = MAXCODE(BITS_MIN)-1;
313 sp->dec_decode = LZWDecode;
314 }
315 sp->lzw_nbits = BITS_MIN;
316 sp->lzw_nextbits = 0;
317 sp->lzw_nextdata = 0;
318
319 sp->dec_restart = 0;
320 sp->dec_nbitsmask = MAXCODE(BITS_MIN);
321 #ifdef LZW_CHECKEOS
322 sp->dec_bitsleft = ((uint64)tif->tif_rawcc) << 3;
323 #endif
324 sp->dec_free_entp = sp->dec_codetab + CODE_FIRST;
325 /*
326 * Zero entries that are not yet filled in. We do
327 * this to guard against bogus input data that causes
328 * us to index into undefined entries. If you can
329 * come up with a way to safely bounds-check input codes
330 * while decoding then you can remove this operation.
331 */
332 _TIFFmemset(sp->dec_free_entp, 0, (CSIZE-CODE_FIRST)*sizeof (code_t));
333 sp->dec_oldcodep = &sp->dec_codetab[-1];
334 sp->dec_maxcodep = &sp->dec_codetab[sp->dec_nbitsmask-1];
335 return (1);
336 }
337
338 /*
339 * Decode a "hunk of data".
340 */
341 #define GetNextCode(sp, bp, code) { \
342 nextdata = (nextdata<<8) | *(bp)++; \
343 nextbits += 8; \
344 if (nextbits < nbits) { \
345 nextdata = (nextdata<<8) | *(bp)++; \
346 nextbits += 8; \
347 } \
348 code = (hcode_t)((nextdata >> (nextbits-nbits)) & nbitsmask); \
349 nextbits -= nbits; \
350 }
351
352 static void
353 codeLoop(TIFF* tif, const char* module)
354 {
355 TIFFErrorExt(tif->tif_clientdata, module,
356 "Bogus encoding, loop in the code table; scanline %d",
357 tif->tif_row);
358 }
359
360 static int
361 LZWDecode(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
362 {
363 static const char module[] = "LZWDecode";
364 LZWCodecState *sp = DecoderState(tif);
365 char *op = (char*) op0;
366 long occ = (long) occ0;
367 char *tp;
368 unsigned char *bp;
369 hcode_t code;
370 int len;
371 long nbits, nextbits, nbitsmask;
372 unsigned long nextdata;
373 code_t *codep, *free_entp, *maxcodep, *oldcodep;
374
375 (void) s;
376 assert(sp != NULL);
377 assert(sp->dec_codetab != NULL);
378
379 /*
380 Fail if value does not fit in long.
381 */
382 if ((tmsize_t) occ != occ0)
383 return (0);
384 /*
385 * Restart interrupted output operation.
386 */
387 if (sp->dec_restart) {
388 long residue;
389
390 codep = sp->dec_codep;
391 residue = codep->length - sp->dec_restart;
392 if (residue > occ) {
393 /*
394 * Residue from previous decode is sufficient
395 * to satisfy decode request. Skip to the
396 * start of the decoded string, place decoded
397 * values in the output buffer, and return.
398 */
399 sp->dec_restart += occ;
400 do {
401 codep = codep->next;
402 } while (--residue > occ && codep);
403 if (codep) {
404 tp = op + occ;
405 do {
406 *--tp = codep->value;
407 codep = codep->next;
408 } while (--occ && codep);
409 }
410 return (1);
411 }
412 /*
413 * Residue satisfies only part of the decode request.
414 */
415 op += residue;
416 occ -= residue;
417 tp = op;
418 do {
419 int t;
420 --tp;
421 t = codep->value;
422 codep = codep->next;
423 *tp = (char)t;
424 } while (--residue && codep);
425 sp->dec_restart = 0;
426 }
427
428 bp = (unsigned char *)tif->tif_rawcp;
429 nbits = sp->lzw_nbits;
430 nextdata = sp->lzw_nextdata;
431 nextbits = sp->lzw_nextbits;
432 nbitsmask = sp->dec_nbitsmask;
433 oldcodep = sp->dec_oldcodep;
434 free_entp = sp->dec_free_entp;
435 maxcodep = sp->dec_maxcodep;
436
437 while (occ > 0) {
438 NextCode(tif, sp, bp, code, GetNextCode);
439 if (code == CODE_EOI)
440 break;
441 if (code == CODE_CLEAR) {
442 do {
443 free_entp = sp->dec_codetab + CODE_FIRST;
444 _TIFFmemset(free_entp, 0,
445 (CSIZE - CODE_FIRST) * sizeof (code_t));
446 nbits = BITS_MIN;
447 nbitsmask = MAXCODE(BITS_MIN);
448 maxcodep = sp->dec_codetab + nbitsmask-1;
449 NextCode(tif, sp, bp, code, GetNextCode);
450 } while (code == CODE_CLEAR); /* consecutive CODE_CLEAR codes */
451 if (code == CODE_EOI)
452 break;
453 if (code > CODE_CLEAR) {
454 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
455 "LZWDecode: Corrupted LZW table at scanline %d",
456 tif->tif_row);
457 return (0);
458 }
459 *op++ = (char)code;
460 occ--;
461 oldcodep = sp->dec_codetab + code;
462 continue;
463 }
464 codep = sp->dec_codetab + code;
465
466 /*
467 * Add the new entry to the code table.
468 */
469 if (free_entp < &sp->dec_codetab[0] ||
470 free_entp >= &sp->dec_codetab[CSIZE]) {
471 TIFFErrorExt(tif->tif_clientdata, module,
472 "Corrupted LZW table at scanline %d",
473 tif->tif_row);
474 return (0);
475 }
476
477 free_entp->next = oldcodep;
478 if (free_entp->next < &sp->dec_codetab[0] ||
479 free_entp->next >= &sp->dec_codetab[CSIZE]) {
480 TIFFErrorExt(tif->tif_clientdata, module,
481 "Corrupted LZW table at scanline %d",
482 tif->tif_row);
483 return (0);
484 }
485 free_entp->firstchar = free_entp->next->firstchar;
486 free_entp->length = free_entp->next->length+1;
487 free_entp->value = (codep < free_entp) ?
488 codep->firstchar : free_entp->firstchar;
489 if (++free_entp > maxcodep) {
490 if (++nbits > BITS_MAX) /* should not happen */
491 nbits = BITS_MAX;
492 nbitsmask = MAXCODE(nbits);
493 maxcodep = sp->dec_codetab + nbitsmask-1;
494 }
495 oldcodep = codep;
496 if (code >= 256) {
497 /*
498 * Code maps to a string, copy string
499 * value to output (written in reverse).
500 */
501 if(codep->length == 0) {
502 TIFFErrorExt(tif->tif_clientdata, module,
503 "Wrong length of decoded string: "
504 "data probably corrupted at scanline %d",
505 tif->tif_row);
506 return (0);
507 }
508 if (codep->length > occ) {
509 /*
510 * String is too long for decode buffer,
511 * locate portion that will fit, copy to
512 * the decode buffer, and setup restart
513 * logic for the next decoding call.
514 */
515 sp->dec_codep = codep;
516 do {
517 codep = codep->next;
518 } while (codep && codep->length > occ);
519 if (codep) {
520 sp->dec_restart = (long)occ;
521 tp = op + occ;
522 do {
523 *--tp = codep->value;
524 codep = codep->next;
525 } while (--occ && codep);
526 if (codep)
527 codeLoop(tif, module);
528 }
529 break;
530 }
531 len = codep->length;
532 tp = op + len;
533 do {
534 int t;
535 --tp;
536 t = codep->value;
537 codep = codep->next;
538 *tp = (char)t;
539 } while (codep && tp > op);
540 if (codep) {
541 codeLoop(tif, module);
542 break;
543 }
544 assert(occ >= len);
545 op += len;
546 occ -= len;
547 } else {
548 *op++ = (char)code;
549 occ--;
550 }
551 }
552
553 tif->tif_rawcp = (uint8*) bp;
554 sp->lzw_nbits = (unsigned short) nbits;
555 sp->lzw_nextdata = nextdata;
556 sp->lzw_nextbits = nextbits;
557 sp->dec_nbitsmask = nbitsmask;
558 sp->dec_oldcodep = oldcodep;
559 sp->dec_free_entp = free_entp;
560 sp->dec_maxcodep = maxcodep;
561
562 if (occ > 0) {
563 #if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
564 TIFFErrorExt(tif->tif_clientdata, module,
565 "Not enough data at scanline %d (short %I64d bytes)",
566 tif->tif_row, (unsigned __int64) occ);
567 #else
568 TIFFErrorExt(tif->tif_clientdata, module,
569 "Not enough data at scanline %d (short %llu bytes)",
570 tif->tif_row, (unsigned long long) occ);
571 #endif
572 return (0);
573 }
574 return (1);
575 }
576
577 #ifdef LZW_COMPAT
578 /*
579 * Decode a "hunk of data" for old images.
580 */
581 #define GetNextCodeCompat(sp, bp, code) { \
582 nextdata |= (unsigned long) *(bp)++ << nextbits; \
583 nextbits += 8; \
584 if (nextbits < nbits) { \
585 nextdata |= (unsigned long) *(bp)++ << nextbits;\
586 nextbits += 8; \
587 } \
588 code = (hcode_t)(nextdata & nbitsmask); \
589 nextdata >>= nbits; \
590 nextbits -= nbits; \
591 }
592
593 static int
594 LZWDecodeCompat(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
595 {
596 static const char module[] = "LZWDecodeCompat";
597 LZWCodecState *sp = DecoderState(tif);
598 char *op = (char*) op0;
599 long occ = (long) occ0;
600 char *tp;
601 unsigned char *bp;
602 int code, nbits;
603 long nextbits, nextdata, nbitsmask;
604 code_t *codep, *free_entp, *maxcodep, *oldcodep;
605
606 (void) s;
607 assert(sp != NULL);
608
609 /*
610 Fail if value does not fit in long.
611 */
612 if ((tmsize_t) occ != occ0)
613 return (0);
614
615 /*
616 * Restart interrupted output operation.
617 */
618 if (sp->dec_restart) {
619 long residue;
620
621 codep = sp->dec_codep;
622 residue = codep->length - sp->dec_restart;
623 if (residue > occ) {
624 /*
625 * Residue from previous decode is sufficient
626 * to satisfy decode request. Skip to the
627 * start of the decoded string, place decoded
628 * values in the output buffer, and return.
629 */
630 sp->dec_restart += occ;
631 do {
632 codep = codep->next;
633 } while (--residue > occ);
634 tp = op + occ;
635 do {
636 *--tp = codep->value;
637 codep = codep->next;
638 } while (--occ);
639 return (1);
640 }
641 /*
642 * Residue satisfies only part of the decode request.
643 */
644 op += residue;
645 occ -= residue;
646 tp = op;
647 do {
648 *--tp = codep->value;
649 codep = codep->next;
650 } while (--residue);
651 sp->dec_restart = 0;
652 }
653
654 bp = (unsigned char *)tif->tif_rawcp;
655 nbits = sp->lzw_nbits;
656 nextdata = sp->lzw_nextdata;
657 nextbits = sp->lzw_nextbits;
658 nbitsmask = sp->dec_nbitsmask;
659 oldcodep = sp->dec_oldcodep;
660 free_entp = sp->dec_free_entp;
661 maxcodep = sp->dec_maxcodep;
662
663 while (occ > 0) {
664 NextCode(tif, sp, bp, code, GetNextCodeCompat);
665 if (code == CODE_EOI)
666 break;
667 if (code == CODE_CLEAR) {
668 do {
669 free_entp = sp->dec_codetab + CODE_FIRST;
670 _TIFFmemset(free_entp, 0,
671 (CSIZE - CODE_FIRST) * sizeof (code_t));
672 nbits = BITS_MIN;
673 nbitsmask = MAXCODE(BITS_MIN);
674 maxcodep = sp->dec_codetab + nbitsmask;
675 NextCode(tif, sp, bp, code, GetNextCodeCompat);
676 } while (code == CODE_CLEAR); /* consecutive CODE_CLEAR codes */
677 if (code == CODE_EOI)
678 break;
679 if (code > CODE_CLEAR) {
680 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
681 "LZWDecode: Corrupted LZW table at scanline %d",
682 tif->tif_row);
683 return (0);
684 }
685 *op++ = (char)code;
686 occ--;
687 oldcodep = sp->dec_codetab + code;
688 continue;
689 }
690 codep = sp->dec_codetab + code;
691
692 /*
693 * Add the new entry to the code table.
694 */
695 if (free_entp < &sp->dec_codetab[0] ||
696 free_entp >= &sp->dec_codetab[CSIZE]) {
697 TIFFErrorExt(tif->tif_clientdata, module,
698 "Corrupted LZW table at scanline %d", tif->tif_row);
699 return (0);
700 }
701
702 free_entp->next = oldcodep;
703 if (free_entp->next < &sp->dec_codetab[0] ||
704 free_entp->next >= &sp->dec_codetab[CSIZE]) {
705 TIFFErrorExt(tif->tif_clientdata, module,
706 "Corrupted LZW table at scanline %d", tif->tif_row);
707 return (0);
708 }
709 free_entp->firstchar = free_entp->next->firstchar;
710 free_entp->length = free_entp->next->length+1;
711 free_entp->value = (codep < free_entp) ?
712 codep->firstchar : free_entp->firstchar;
713 if (++free_entp > maxcodep) {
714 if (++nbits > BITS_MAX) /* should not happen */
715 nbits = BITS_MAX;
716 nbitsmask = MAXCODE(nbits);
717 maxcodep = sp->dec_codetab + nbitsmask;
718 }
719 oldcodep = codep;
720 if (code >= 256) {
721 /*
722 * Code maps to a string, copy string
723 * value to output (written in reverse).
724 */
725 if(codep->length == 0) {
726 TIFFErrorExt(tif->tif_clientdata, module,
727 "Wrong length of decoded "
728 "string: data probably corrupted at scanline %d",
729 tif->tif_row);
730 return (0);
731 }
732 if (codep->length > occ) {
733 /*
734 * String is too long for decode buffer,
735 * locate portion that will fit, copy to
736 * the decode buffer, and setup restart
737 * logic for the next decoding call.
738 */
739 sp->dec_codep = codep;
740 do {
741 codep = codep->next;
742 } while (codep->length > occ);
743 sp->dec_restart = occ;
744 tp = op + occ;
745 do {
746 *--tp = codep->value;
747 codep = codep->next;
748 } while (--occ);
749 break;
750 }
751 assert(occ >= codep->length);
752 op += codep->length;
753 occ -= codep->length;
754 tp = op;
755 do {
756 *--tp = codep->value;
757 } while( (codep = codep->next) != NULL );
758 } else {
759 *op++ = (char)code;
760 occ--;
761 }
762 }
763
764 tif->tif_rawcp = (uint8*) bp;
765 sp->lzw_nbits = (unsigned short)nbits;
766 sp->lzw_nextdata = nextdata;
767 sp->lzw_nextbits = nextbits;
768 sp->dec_nbitsmask = nbitsmask;
769 sp->dec_oldcodep = oldcodep;
770 sp->dec_free_entp = free_entp;
771 sp->dec_maxcodep = maxcodep;
772
773 if (occ > 0) {
774 #if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
775 TIFFErrorExt(tif->tif_clientdata, module,
776 "Not enough data at scanline %d (short %I64d bytes)",
777 tif->tif_row, (unsigned __int64) occ);
778 #else
779 TIFFErrorExt(tif->tif_clientdata, module,
780 "Not enough data at scanline %d (short %llu bytes)",
781 tif->tif_row, (unsigned long long) occ);
782 #endif
783 return (0);
784 }
785 return (1);
786 }
787 #endif /* LZW_COMPAT */
788
789 /*
790 * LZW Encoding.
791 */
792
793 static int
794 LZWSetupEncode(TIFF* tif)
795 {
796 static const char module[] = "LZWSetupEncode";
797 LZWCodecState* sp = EncoderState(tif);
798
799 assert(sp != NULL);
800 sp->enc_hashtab = (hash_t*) _TIFFmalloc(HSIZE*sizeof (hash_t));
801 if (sp->enc_hashtab == NULL) {
802 TIFFErrorExt(tif->tif_clientdata, module,
803 "No space for LZW hash table");
804 return (0);
805 }
806 return (1);
807 }
808
809 /*
810 * Reset encoding state at the start of a strip.
811 */
812 static int
813 LZWPreEncode(TIFF* tif, uint16 s)
814 {
815 LZWCodecState *sp = EncoderState(tif);
816
817 (void) s;
818 assert(sp != NULL);
819
820 if( sp->enc_hashtab == NULL )
821 {
822 tif->tif_setupencode( tif );
823 }
824
825 sp->lzw_nbits = BITS_MIN;
826 sp->lzw_maxcode = MAXCODE(BITS_MIN);
827 sp->lzw_free_ent = CODE_FIRST;
828 sp->lzw_nextbits = 0;
829 sp->lzw_nextdata = 0;
830 sp->enc_checkpoint = CHECK_GAP;
831 sp->enc_ratio = 0;
832 sp->enc_incount = 0;
833 sp->enc_outcount = 0;
834 /*
835 * The 4 here insures there is space for 2 max-sized
836 * codes in LZWEncode and LZWPostDecode.
837 */
838 sp->enc_rawlimit = tif->tif_rawdata + tif->tif_rawdatasize-1 - 4;
839 cl_hash(sp); /* clear hash table */
840 sp->enc_oldcode = (hcode_t) -1; /* generates CODE_CLEAR in LZWEncode */
841 return (1);
842 }
843
844 #define CALCRATIO(sp, rat) { \
845 if (incount > 0x007fffff) { /* NB: shift will overflow */\
846 rat = outcount >> 8; \
847 rat = (rat == 0 ? 0x7fffffff : incount/rat); \
848 } else \
849 rat = (incount<<8) / outcount; \
850 }
851
852 /* Explicit 0xff masking to make icc -check=conversions happy */
853 #define PutNextCode(op, c) { \
854 nextdata = (nextdata << nbits) | c; \
855 nextbits += nbits; \
856 *op++ = (unsigned char)((nextdata >> (nextbits-8))&0xff); \
857 nextbits -= 8; \
858 if (nextbits >= 8) { \
859 *op++ = (unsigned char)((nextdata >> (nextbits-8))&0xff); \
860 nextbits -= 8; \
861 } \
862 outcount += nbits; \
863 }
864
865 /*
866 * Encode a chunk of pixels.
867 *
868 * Uses an open addressing double hashing (no chaining) on the
869 * prefix code/next character combination. We do a variant of
870 * Knuth's algorithm D (vol. 3, sec. 6.4) along with G. Knott's
871 * relatively-prime secondary probe. Here, the modular division
872 * first probe is gives way to a faster exclusive-or manipulation.
873 * Also do block compression with an adaptive reset, whereby the
874 * code table is cleared when the compression ratio decreases,
875 * but after the table fills. The variable-length output codes
876 * are re-sized at this point, and a CODE_CLEAR is generated
877 * for the decoder.
878 */
879 static int
880 LZWEncode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
881 {
882 register LZWCodecState *sp = EncoderState(tif);
883 register long fcode;
884 register hash_t *hp;
885 register int h, c;
886 hcode_t ent;
887 long disp;
888 long incount, outcount, checkpoint;
889 unsigned long nextdata;
890 long nextbits;
891 int free_ent, maxcode, nbits;
892 uint8* op;
893 uint8* limit;
894
895 (void) s;
896 if (sp == NULL)
897 return (0);
898
899 assert(sp->enc_hashtab != NULL);
900
901 /*
902 * Load local state.
903 */
904 incount = sp->enc_incount;
905 outcount = sp->enc_outcount;
906 checkpoint = sp->enc_checkpoint;
907 nextdata = sp->lzw_nextdata;
908 nextbits = sp->lzw_nextbits;
909 free_ent = sp->lzw_free_ent;
910 maxcode = sp->lzw_maxcode;
911 nbits = sp->lzw_nbits;
912 op = tif->tif_rawcp;
913 limit = sp->enc_rawlimit;
914 ent = (hcode_t)sp->enc_oldcode;
915
916 if (ent == (hcode_t) -1 && cc > 0) {
917 /*
918 * NB: This is safe because it can only happen
919 * at the start of a strip where we know there
920 * is space in the data buffer.
921 */
922 PutNextCode(op, CODE_CLEAR);
923 ent = *bp++; cc--; incount++;
924 }
925 while (cc > 0) {
926 c = *bp++; cc--; incount++;
927 fcode = ((long)c << BITS_MAX) + ent;
928 h = (c << HSHIFT) ^ ent; /* xor hashing */
929 #ifdef _WINDOWS
930 /*
931 * Check hash index for an overflow.
932 */
933 if (h >= HSIZE)
934 h -= HSIZE;
935 #endif
936 hp = &sp->enc_hashtab[h];
937 if (hp->hash == fcode) {
938 ent = hp->code;
939 continue;
940 }
941 if (hp->hash >= 0) {
942 /*
943 * Primary hash failed, check secondary hash.
944 */
945 disp = HSIZE - h;
946 if (h == 0)
947 disp = 1;
948 do {
949 /*
950 * Avoid pointer arithmetic because of
951 * wraparound problems with segments.
952 */
953 if ((h -= disp) < 0)
954 h += HSIZE;
955 hp = &sp->enc_hashtab[h];
956 if (hp->hash == fcode) {
957 ent = hp->code;
958 goto hit;
959 }
960 } while (hp->hash >= 0);
961 }
962 /*
963 * New entry, emit code and add to table.
964 */
965 /*
966 * Verify there is space in the buffer for the code
967 * and any potential Clear code that might be emitted
968 * below. The value of limit is setup so that there
969 * are at least 4 bytes free--room for 2 codes.
970 */
971 if (op > limit) {
972 tif->tif_rawcc = (tmsize_t)(op - tif->tif_rawdata);
973 TIFFFlushData1(tif);
974 op = tif->tif_rawdata;
975 }
976 PutNextCode(op, ent);
977 ent = (hcode_t)c;
978 hp->code = (hcode_t)(free_ent++);
979 hp->hash = fcode;
980 if (free_ent == CODE_MAX-1) {
981 /* table is full, emit clear code and reset */
982 cl_hash(sp);
983 sp->enc_ratio = 0;
984 incount = 0;
985 outcount = 0;
986 free_ent = CODE_FIRST;
987 PutNextCode(op, CODE_CLEAR);
988 nbits = BITS_MIN;
989 maxcode = MAXCODE(BITS_MIN);
990 } else {
991 /*
992 * If the next entry is going to be too big for
993 * the code size, then increase it, if possible.
994 */
995 if (free_ent > maxcode) {
996 nbits++;
997 assert(nbits <= BITS_MAX);
998 maxcode = (int) MAXCODE(nbits);
999 } else if (incount >= checkpoint) {
1000 long rat;
1001 /*
1002 * Check compression ratio and, if things seem
1003 * to be slipping, clear the hash table and
1004 * reset state. The compression ratio is a
1005 * 24+8-bit fractional number.
1006 */
1007 checkpoint = incount+CHECK_GAP;
1008 CALCRATIO(sp, rat);
1009 if (rat <= sp->enc_ratio) {
1010 cl_hash(sp);
1011 sp->enc_ratio = 0;
1012 incount = 0;
1013 outcount = 0;
1014 free_ent = CODE_FIRST;
1015 PutNextCode(op, CODE_CLEAR);
1016 nbits = BITS_MIN;
1017 maxcode = MAXCODE(BITS_MIN);
1018 } else
1019 sp->enc_ratio = rat;
1020 }
1021 }
1022 hit:
1023 ;
1024 }
1025
1026 /*
1027 * Restore global state.
1028 */
1029 sp->enc_incount = incount;
1030 sp->enc_outcount = outcount;
1031 sp->enc_checkpoint = checkpoint;
1032 sp->enc_oldcode = ent;
1033 sp->lzw_nextdata = nextdata;
1034 sp->lzw_nextbits = nextbits;
1035 sp->lzw_free_ent = (unsigned short)free_ent;
1036 sp->lzw_maxcode = (unsigned short)maxcode;
1037 sp->lzw_nbits = (unsigned short)nbits;
1038 tif->tif_rawcp = op;
1039 return (1);
1040 }
1041
1042 /*
1043 * Finish off an encoded strip by flushing the last
1044 * string and tacking on an End Of Information code.
1045 */
1046 static int
1047 LZWPostEncode(TIFF* tif)
1048 {
1049 register LZWCodecState *sp = EncoderState(tif);
1050 uint8* op = tif->tif_rawcp;
1051 long nextbits = sp->lzw_nextbits;
1052 unsigned long nextdata = sp->lzw_nextdata;
1053 long outcount = sp->enc_outcount;
1054 int nbits = sp->lzw_nbits;
1055
1056 if (op > sp->enc_rawlimit) {
1057 tif->tif_rawcc = (tmsize_t)(op - tif->tif_rawdata);
1058 TIFFFlushData1(tif);
1059 op = tif->tif_rawdata;
1060 }
1061 if (sp->enc_oldcode != (hcode_t) -1) {
1062 PutNextCode(op, sp->enc_oldcode);
1063 sp->enc_oldcode = (hcode_t) -1;
1064 }
1065 PutNextCode(op, CODE_EOI);
1066 /* Explicit 0xff masking to make icc -check=conversions happy */
1067 if (nextbits > 0)
1068 *op++ = (unsigned char)((nextdata << (8-nextbits))&0xff);
1069 tif->tif_rawcc = (tmsize_t)(op - tif->tif_rawdata);
1070 return (1);
1071 }
1072
1073 /*
1074 * Reset encoding hash table.
1075 */
1076 static void
1077 cl_hash(LZWCodecState* sp)
1078 {
1079 register hash_t *hp = &sp->enc_hashtab[HSIZE-1];
1080 register long i = HSIZE-8;
1081
1082 do {
1083 i -= 8;
1084 hp[-7].hash = -1;
1085 hp[-6].hash = -1;
1086 hp[-5].hash = -1;
1087 hp[-4].hash = -1;
1088 hp[-3].hash = -1;
1089 hp[-2].hash = -1;
1090 hp[-1].hash = -1;
1091 hp[ 0].hash = -1;
1092 hp -= 8;
1093 } while (i >= 0);
1094 for (i += 8; i > 0; i--, hp--)
1095 hp->hash = -1;
1096 }
1097
1098 static void
1099 LZWCleanup(TIFF* tif)
1100 {
1101 (void)TIFFPredictorCleanup(tif);
1102
1103 assert(tif->tif_data != 0);
1104
1105 if (DecoderState(tif)->dec_codetab)
1106 _TIFFfree(DecoderState(tif)->dec_codetab);
1107
1108 if (EncoderState(tif)->enc_hashtab)
1109 _TIFFfree(EncoderState(tif)->enc_hashtab);
1110
1111 _TIFFfree(tif->tif_data);
1112 tif->tif_data = NULL;
1113
1114 _TIFFSetDefaultCompressionState(tif);
1115 }
1116
1117 int
1118 TIFFInitLZW(TIFF* tif, int scheme)
1119 {
1120 static const char module[] = "TIFFInitLZW";
1121 assert(scheme == COMPRESSION_LZW);
1122 /*
1123 * Allocate state block so tag methods have storage to record values.
1124 */
1125 tif->tif_data = (uint8*) _TIFFmalloc(sizeof (LZWCodecState));
1126 if (tif->tif_data == NULL)
1127 goto bad;
1128 DecoderState(tif)->dec_codetab = NULL;
1129 DecoderState(tif)->dec_decode = NULL;
1130 EncoderState(tif)->enc_hashtab = NULL;
1131 LZWState(tif)->rw_mode = tif->tif_mode;
1132
1133 /*
1134 * Install codec methods.
1135 */
1136 tif->tif_fixuptags = LZWFixupTags;
1137 tif->tif_setupdecode = LZWSetupDecode;
1138 tif->tif_predecode = LZWPreDecode;
1139 tif->tif_decoderow = LZWDecode;
1140 tif->tif_decodestrip = LZWDecode;
1141 tif->tif_decodetile = LZWDecode;
1142 tif->tif_setupencode = LZWSetupEncode;
1143 tif->tif_preencode = LZWPreEncode;
1144 tif->tif_postencode = LZWPostEncode;
1145 tif->tif_encoderow = LZWEncode;
1146 tif->tif_encodestrip = LZWEncode;
1147 tif->tif_encodetile = LZWEncode;
1148 tif->tif_cleanup = LZWCleanup;
1149 /*
1150 * Setup predictor setup.
1151 */
1152 (void) TIFFPredictorInit(tif);
1153 return (1);
1154 bad:
1155 TIFFErrorExt(tif->tif_clientdata, module,
1156 "No space for LZW state block");
1157 return (0);
1158 }
1159
1160 /*
1161 * Copyright (c) 1985, 1986 The Regents of the University of California.
1162 * All rights reserved.
1163 *
1164 * This code is derived from software contributed to Berkeley by
1165 * James A. Woods, derived from original work by Spencer Thomas
1166 * and Joseph Orost.
1167 *
1168 * Redistribution and use in source and binary forms are permitted
1169 * provided that the above copyright notice and this paragraph are
1170 * duplicated in all such forms and that any documentation,
1171 * advertising materials, and other materials related to such
1172 * distribution and use acknowledge that the software was developed
1173 * by the University of California, Berkeley. The name of the
1174 * University may not be used to endorse or promote products derived
1175 * from this software without specific prior written permission.
1176 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
1177 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
1178 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
1179 */
1180 #endif /* LZW_SUPPORT */
1181
1182 /* vim: set ts=8 sts=8 sw=8 noet: */
1183 /*
1184 * Local Variables:
1185 * mode: c
1186 * c-basic-offset: 8
1187 * fill-column: 78
1188 * End:
1189 */
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