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1 /* deflate.c -- compress data using the deflat 1
2 * Copyright (C) 1995-2022 Jean-loup Gailly an
3 * For conditions of distribution and use, see
4 */
5
6 /*
7 * ALGORITHM
8 *
9 * The "deflation" process depends on bei
10 * of the input text which are identical
11 * sliding window trailing behind the inp
12 *
13 * The most straightforward technique tur
14 * most input files: try all possible mat
15 * The key feature of this algorithm is t
16 * dictionary are very simple and thus fa
17 * completely. Insertions are performed a
18 * string matches are performed only when
19 * is preferable to spend more time in ma
20 * insertions and avoid deletions. The ma
21 * strings is inspired from that of Rabin
22 * is used to find longer strings when a
23 * A similar algorithm is used in comic (
24 * (by Leonid Broukhis).
25 * A previous version of this file use
26 * (by Fiala and Greene) which is guarant
27 * time, but has a larger average cost, u
28 * However the F&G algorithm may be faste
29 * files if the parameter max_chain_lengt
30 *
31 * ACKNOWLEDGEMENTS
32 *
33 * The idea of lazy evaluation of matches
34 * I found it in 'freeze' written by Leon
35 * Thanks to many people for bug reports
36 *
37 * REFERENCES
38 *
39 * Deutsch, L.P.,"DEFLATE Compressed Data
40 * Available in http://tools.ietf.org/htm
41 *
42 * A description of the Rabin and Karp al
43 * "Algorithms" by R. Sedgewick, Addis
44 *
45 * Fiala,E.R., and Greene,D.H.
46 * Data Compression with Finite Window
47 *
48 */
49
50 /* @(#) $Id$ */
51
52 #include "deflate.h"
53
54 const char deflate_copyright[] =
55 " deflate 1.2.13 Copyright 1995-2022 Jean-l
56 /*
57 If you use the zlib library in a product, an
58 in the documentation of your product. If for
59 include such an acknowledgment, I would appr
60 copyright string in the executable of your p
61 */
62
63 /* ===========================================
64 * Function prototypes.
65 */
66 typedef enum {
67 need_more, /* block not completed, ne
68 block_done, /* block flush performed *
69 finish_started, /* finish started, need on
70 finish_done /* finish done, accept no
71 } block_state;
72
73 typedef block_state (*compress_func) OF((defla
74 /* Compression function. Returns the block sta
75
76 local int deflateStateCheck OF((z_streamp
77 local void slide_hash OF((deflate_state *s
78 local void fill_window OF((deflate_state *s
79 local block_state deflate_stored OF((deflate_s
80 local block_state deflate_fast OF((deflate_s
81 #ifndef FASTEST
82 local block_state deflate_slow OF((deflate_s
83 #endif
84 local block_state deflate_rle OF((deflate_s
85 local block_state deflate_huff OF((deflate_s
86 local void lm_init OF((deflate_state *s
87 local void putShortMSB OF((deflate_state *s
88 local void flush_pending OF((z_streamp strm))
89 local unsigned read_buf OF((z_streamp strm,
90 local uInt longest_match OF((deflate_state *s
91
92 #ifdef ZLIB_DEBUG
93 local void check_match OF((deflate_state *s,
94 int length));
95 #endif
96
97 /* ===========================================
98 * Local data
99 */
100
101 #define NIL 0
102 /* Tail of hash chains */
103
104 #ifndef TOO_FAR
105 # define TOO_FAR 4096
106 #endif
107 /* Matches of length 3 are discarded if their
108
109 /* Values for max_lazy_match, good_match and m
110 * the desired pack level (0..9). The values g
111 * exclude worst case performance for patholog
112 * found for specific files.
113 */
114 typedef struct config_s {
115 ush good_length; /* reduce lazy search abov
116 ush max_lazy; /* do not perform lazy sea
117 ush nice_length; /* quit search above this
118 ush max_chain;
119 compress_func func;
120 } config;
121
122 #ifdef FASTEST
123 local const config configuration_table[2] = {
124 /* good lazy nice chain */
125 /* 0 */ {0, 0, 0, 0, deflate_stored},
126 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /*
127 #else
128 local const config configuration_table[10] = {
129 /* good lazy nice chain */
130 /* 0 */ {0, 0, 0, 0, deflate_stored},
131 /* 1 */ {4, 4, 8, 4, deflate_fast}, /*
132 /* 2 */ {4, 5, 16, 8, deflate_fast},
133 /* 3 */ {4, 6, 32, 32, deflate_fast},
134
135 /* 4 */ {4, 4, 16, 16, deflate_slow}, /*
136 /* 5 */ {8, 16, 32, 32, deflate_slow},
137 /* 6 */ {8, 16, 128, 128, deflate_slow},
138 /* 7 */ {8, 32, 128, 256, deflate_slow},
139 /* 8 */ {32, 128, 258, 1024, deflate_slow},
140 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /
141 #endif
142
143 /* Note: the deflate() code requires max_lazy
144 * For deflate_fast() (levels <= 3) good is ig
145 * meaning.
146 */
147
148 /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTI
149 #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0)
150
151 /* ===========================================
152 * Update a hash value with the given input by
153 * IN assertion: all calls to UPDATE_HASH are
154 * characters, so that a running hash key c
155 * key instead of complete recalculation ea
156 */
157 #define UPDATE_HASH(s,h,c) (h = (((h) << s->ha
158
159
160 /* ===========================================
161 * Insert string str in the dictionary and set
162 * of the hash chain (the most recent string w
163 * the previous length of the hash chain.
164 * If this file is compiled with -DFASTEST, th
165 * to 1, and no hash chains are maintained.
166 * IN assertion: all calls to INSERT_STRING a
167 * characters and the first MIN_MATCH bytes
168 * the last MIN_MATCH-1 bytes of the input
169 */
170 #ifdef FASTEST
171 #define INSERT_STRING(s, str, match_head) \
172 (UPDATE_HASH(s, s->ins_h, s->window[(str) +
173 match_head = s->head[s->ins_h], \
174 s->head[s->ins_h] = (Pos)(str))
175 #else
176 #define INSERT_STRING(s, str, match_head) \
177 (UPDATE_HASH(s, s->ins_h, s->window[(str) +
178 match_head = s->prev[(str) & s->w_mask] =
179 s->head[s->ins_h] = (Pos)(str))
180 #endif
181
182 /* ===========================================
183 * Initialize the hash table (avoiding 64K ove
184 * prev[] will be initialized on the fly.
185 */
186 #define CLEAR_HASH(s) \
187 do { \
188 s->head[s->hash_size - 1] = NIL; \
189 zmemzero((Bytef *)s->head, \
190 (unsigned)(s->hash_size - 1)*
191 } while (0)
192
193 /* ===========================================
194 * Slide the hash table when sliding the windo
195 * bit values at the expense of memory usage).
196 * keep the hash table consistent if we switch
197 */
198 local void slide_hash(s)
199 deflate_state *s;
200 {
201 unsigned n, m;
202 Posf *p;
203 uInt wsize = s->w_size;
204
205 n = s->hash_size;
206 p = &s->head[n];
207 do {
208 m = *--p;
209 *p = (Pos)(m >= wsize ? m - wsize : NI
210 } while (--n);
211 n = wsize;
212 #ifndef FASTEST
213 p = &s->prev[n];
214 do {
215 m = *--p;
216 *p = (Pos)(m >= wsize ? m - wsize : NI
217 /* If n is not on any hash chain, prev
218 * its value will never be used.
219 */
220 } while (--n);
221 #endif
222 }
223
224 /* ===========================================
225 int ZEXPORT deflateInit_(strm, level, version,
226 z_streamp strm;
227 int level;
228 const char *version;
229 int stream_size;
230 {
231 return deflateInit2_(strm, level, Z_DEFLAT
232 Z_DEFAULT_STRATEGY, v
233 /* To do: ignore strm->next_in if we use i
234 }
235
236 /* ===========================================
237 int ZEXPORT deflateInit2_(strm, level, method,
238 version, stream_size)
239 z_streamp strm;
240 int level;
241 int method;
242 int windowBits;
243 int memLevel;
244 int strategy;
245 const char *version;
246 int stream_size;
247 {
248 deflate_state *s;
249 int wrap = 1;
250 static const char my_version[] = ZLIB_VERS
251
252 if (version == Z_NULL || version[0] != my_
253 stream_size != sizeof(z_stream)) {
254 return Z_VERSION_ERROR;
255 }
256 if (strm == Z_NULL) return Z_STREAM_ERROR;
257
258 strm->msg = Z_NULL;
259 if (strm->zalloc == (alloc_func)0) {
260 #ifdef Z_SOLO
261 return Z_STREAM_ERROR;
262 #else
263 strm->zalloc = zcalloc;
264 strm->opaque = (voidpf)0;
265 #endif
266 }
267 if (strm->zfree == (free_func)0)
268 #ifdef Z_SOLO
269 return Z_STREAM_ERROR;
270 #else
271 strm->zfree = zcfree;
272 #endif
273
274 #ifdef FASTEST
275 if (level != 0) level = 1;
276 #else
277 if (level == Z_DEFAULT_COMPRESSION) level
278 #endif
279
280 if (windowBits < 0) { /* suppress zlib wra
281 wrap = 0;
282 if (windowBits < -15)
283 return Z_STREAM_ERROR;
284 windowBits = -windowBits;
285 }
286 #ifdef GZIP
287 else if (windowBits > 15) {
288 wrap = 2; /* write gzip wrapper
289 windowBits -= 16;
290 }
291 #endif
292 if (memLevel < 1 || memLevel > MAX_MEM_LEV
293 windowBits < 8 || windowBits > 15 || l
294 strategy < 0 || strategy > Z_FIXED ||
295 return Z_STREAM_ERROR;
296 }
297 if (windowBits == 8) windowBits = 9; /* u
298 s = (deflate_state *) ZALLOC(strm, 1, size
299 if (s == Z_NULL) return Z_MEM_ERROR;
300 strm->state = (struct internal_state FAR *
301 s->strm = strm;
302 s->status = INIT_STATE; /* to pass sta
303
304 s->wrap = wrap;
305 s->gzhead = Z_NULL;
306 s->w_bits = (uInt)windowBits;
307 s->w_size = 1 << s->w_bits;
308 s->w_mask = s->w_size - 1;
309
310 s->hash_bits = (uInt)memLevel + 7;
311 s->hash_size = 1 << s->hash_bits;
312 s->hash_mask = s->hash_size - 1;
313 s->hash_shift = ((s->hash_bits + MIN_MATC
314
315 s->window = (Bytef *) ZALLOC(strm, s->w_si
316 s->prev = (Posf *) ZALLOC(strm, s->w_si
317 /* Avoid use of uninitialized value, see:
318 * https://bugs.chromium.org/p/oss-fuzz/is
319 */
320 zmemzero(s->prev, s->w_size * sizeof(Pos))
321 s->head = (Posf *) ZALLOC(strm, s->hash
322
323 s->high_water = 0; /* nothing written
324
325 s->lit_bufsize = 1 << (memLevel + 6); /* 1
326
327 /* We overlay pending_buf and sym_buf. Thi
328 * for length/distance pairs over any comp
329 * bits or less.
330 *
331 * Analysis: The longest fixed codes are a
332 * extra bits, for lengths 131 to 257. The
333 * 5 bits plus 13 extra bits, for distance
334 * possible fixed-codes length/distance pa
335 *
336 * sym_buf starts one-fourth of the way in
337 * three bytes in sym_buf for every four b
338 * in sym_buf is three bytes -- two for th
339 * literal/length. As each symbol is consu
340 * sym_buf value to read moves forward thr
341 * 31 bits are written to pending_buf. The
342 * bits gets to the next sym_buf symbol to
343 * code is written. At that time, 31*(n -
344 * after 24*(n - 2) bits have been consume
345 * 8*n bits into pending_buf. (Note that t
346 * symbols are written.) The closest the w
347 * then n + 14 bits. Here n is lit_bufsize
348 * can range from 128 to 32768.
349 *
350 * Therefore, at a minimum, there are 142
351 * written and what is read in the overlai
352 * be overwritten by the compressed data.
353 * due to the three-bit fixed-code block h
354 *
355 * That covers the case where either Z_FIX
356 * codes, or when the use of fixed codes i
357 * results in a smaller compressed block t
358 * condition then assures that the above a
359 * blocks. A dynamic-code block will only
360 * fewer bits than a fixed-code block woul
361 * Therefore its average symbol length is
362 * the compressed data for a dynamic block
363 * symbols from which it is being construc
364 */
365
366 s->pending_buf = (uchf *) ZALLOC(strm, s->
367 s->pending_buf_size = (ulg)s->lit_bufsize
368
369 if (s->window == Z_NULL || s->prev == Z_NU
370 s->pending_buf == Z_NULL) {
371 s->status = FINISH_STATE;
372 strm->msg = ERR_MSG(Z_MEM_ERROR);
373 deflateEnd (strm);
374 return Z_MEM_ERROR;
375 }
376 s->sym_buf = s->pending_buf + s->lit_bufsi
377 s->sym_end = (s->lit_bufsize - 1) * 3;
378 /* We avoid equality with lit_bufsize*3 be
379 * on 16 bit machines and because stored b
380 * 64K-1 bytes.
381 */
382
383 s->level = level;
384 s->strategy = strategy;
385 s->method = (Byte)method;
386
387 return deflateReset(strm);
388 }
389
390 /* ===========================================
391 * Check for a valid deflate stream state. Ret
392 */
393 local int deflateStateCheck(strm)
394 z_streamp strm;
395 {
396 deflate_state *s;
397 if (strm == Z_NULL ||
398 strm->zalloc == (alloc_func)0 || strm-
399 return 1;
400 s = strm->state;
401 if (s == Z_NULL || s->strm != strm || (s->
402 #ifdef GZIP
403 s->
404 #endif
405 s->
406 s->
407 s->
408 s->
409 s->
410 s->
411 return 1;
412 return 0;
413 }
414
415 /* ===========================================
416 int ZEXPORT deflateSetDictionary(strm, diction
417 z_streamp strm;
418 const Bytef *dictionary;
419 uInt dictLength;
420 {
421 deflate_state *s;
422 uInt str, n;
423 int wrap;
424 unsigned avail;
425 z_const unsigned char *next;
426
427 if (deflateStateCheck(strm) || dictionary
428 return Z_STREAM_ERROR;
429 s = strm->state;
430 wrap = s->wrap;
431 if (wrap == 2 || (wrap == 1 && s->status !
432 return Z_STREAM_ERROR;
433
434 /* when using zlib wrappers, compute Adler
435 if (wrap == 1)
436 strm->adler = adler32(strm->adler, dic
437 s->wrap = 0; /* avoid c
438
439 /* if dictionary would fill window, just r
440 if (dictLength >= s->w_size) {
441 if (wrap == 0) { /* already
442 CLEAR_HASH(s);
443 s->strstart = 0;
444 s->block_start = 0L;
445 s->insert = 0;
446 }
447 dictionary += dictLength - s->w_size;
448 dictLength = s->w_size;
449 }
450
451 /* insert dictionary into window and hash
452 avail = strm->avail_in;
453 next = strm->next_in;
454 strm->avail_in = dictLength;
455 strm->next_in = (z_const Bytef *)dictionar
456 fill_window(s);
457 while (s->lookahead >= MIN_MATCH) {
458 str = s->strstart;
459 n = s->lookahead - (MIN_MATCH-1);
460 do {
461 UPDATE_HASH(s, s->ins_h, s->window
462 #ifndef FASTEST
463 s->prev[str & s->w_mask] = s->head
464 #endif
465 s->head[s->ins_h] = (Pos)str;
466 str++;
467 } while (--n);
468 s->strstart = str;
469 s->lookahead = MIN_MATCH-1;
470 fill_window(s);
471 }
472 s->strstart += s->lookahead;
473 s->block_start = (long)s->strstart;
474 s->insert = s->lookahead;
475 s->lookahead = 0;
476 s->match_length = s->prev_length = MIN_MAT
477 s->match_available = 0;
478 strm->next_in = next;
479 strm->avail_in = avail;
480 s->wrap = wrap;
481 return Z_OK;
482 }
483
484 /* ===========================================
485 int ZEXPORT deflateGetDictionary(strm, diction
486 z_streamp strm;
487 Bytef *dictionary;
488 uInt *dictLength;
489 {
490 deflate_state *s;
491 uInt len;
492
493 if (deflateStateCheck(strm))
494 return Z_STREAM_ERROR;
495 s = strm->state;
496 len = s->strstart + s->lookahead;
497 if (len > s->w_size)
498 len = s->w_size;
499 if (dictionary != Z_NULL && len)
500 zmemcpy(dictionary, s->window + s->str
501 if (dictLength != Z_NULL)
502 *dictLength = len;
503 return Z_OK;
504 }
505
506 /* ===========================================
507 int ZEXPORT deflateResetKeep(strm)
508 z_streamp strm;
509 {
510 deflate_state *s;
511
512 if (deflateStateCheck(strm)) {
513 return Z_STREAM_ERROR;
514 }
515
516 strm->total_in = strm->total_out = 0;
517 strm->msg = Z_NULL; /* use zfree if we eve
518 strm->data_type = Z_UNKNOWN;
519
520 s = (deflate_state *)strm->state;
521 s->pending = 0;
522 s->pending_out = s->pending_buf;
523
524 if (s->wrap < 0) {
525 s->wrap = -s->wrap; /* was made negati
526 }
527 s->status =
528 #ifdef GZIP
529 s->wrap == 2 ? GZIP_STATE :
530 #endif
531 INIT_STATE;
532 strm->adler =
533 #ifdef GZIP
534 s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
535 #endif
536 adler32(0L, Z_NULL, 0);
537 s->last_flush = -2;
538
539 _tr_init(s);
540
541 return Z_OK;
542 }
543
544 /* ===========================================
545 int ZEXPORT deflateReset(strm)
546 z_streamp strm;
547 {
548 int ret;
549
550 ret = deflateResetKeep(strm);
551 if (ret == Z_OK)
552 lm_init(strm->state);
553 return ret;
554 }
555
556 /* ===========================================
557 int ZEXPORT deflateSetHeader(strm, head)
558 z_streamp strm;
559 gz_headerp head;
560 {
561 if (deflateStateCheck(strm) || strm->state
562 return Z_STREAM_ERROR;
563 strm->state->gzhead = head;
564 return Z_OK;
565 }
566
567 /* ===========================================
568 int ZEXPORT deflatePending(strm, pending, bits
569 unsigned *pending;
570 int *bits;
571 z_streamp strm;
572 {
573 if (deflateStateCheck(strm)) return Z_STRE
574 if (pending != Z_NULL)
575 *pending = strm->state->pending;
576 if (bits != Z_NULL)
577 *bits = strm->state->bi_valid;
578 return Z_OK;
579 }
580
581 /* ===========================================
582 int ZEXPORT deflatePrime(strm, bits, value)
583 z_streamp strm;
584 int bits;
585 int value;
586 {
587 deflate_state *s;
588 int put;
589
590 if (deflateStateCheck(strm)) return Z_STRE
591 s = strm->state;
592 if (bits < 0 || bits > 16 ||
593 s->sym_buf < s->pending_out + ((Buf_si
594 return Z_BUF_ERROR;
595 do {
596 put = Buf_size - s->bi_valid;
597 if (put > bits)
598 put = bits;
599 s->bi_buf |= (ush)((value & ((1 << put
600 s->bi_valid += put;
601 _tr_flush_bits(s);
602 value >>= put;
603 bits -= put;
604 } while (bits);
605 return Z_OK;
606 }
607
608 /* ===========================================
609 int ZEXPORT deflateParams(strm, level, strateg
610 z_streamp strm;
611 int level;
612 int strategy;
613 {
614 deflate_state *s;
615 compress_func func;
616
617 if (deflateStateCheck(strm)) return Z_STRE
618 s = strm->state;
619
620 #ifdef FASTEST
621 if (level != 0) level = 1;
622 #else
623 if (level == Z_DEFAULT_COMPRESSION) level
624 #endif
625 if (level < 0 || level > 9 || strategy < 0
626 return Z_STREAM_ERROR;
627 }
628 func = configuration_table[s->level].func;
629
630 if ((strategy != s->strategy || func != co
631 s->last_flush != -2) {
632 /* Flush the last buffer: */
633 int err = deflate(strm, Z_BLOCK);
634 if (err == Z_STREAM_ERROR)
635 return err;
636 if (strm->avail_in || (s->strstart - s
637 return Z_BUF_ERROR;
638 }
639 if (s->level != level) {
640 if (s->level == 0 && s->matches != 0)
641 if (s->matches == 1)
642 slide_hash(s);
643 else
644 CLEAR_HASH(s);
645 s->matches = 0;
646 }
647 s->level = level;
648 s->max_lazy_match = configuration_ta
649 s->good_match = configuration_ta
650 s->nice_match = configuration_ta
651 s->max_chain_length = configuration_ta
652 }
653 s->strategy = strategy;
654 return Z_OK;
655 }
656
657 /* ===========================================
658 int ZEXPORT deflateTune(strm, good_length, max
659 z_streamp strm;
660 int good_length;
661 int max_lazy;
662 int nice_length;
663 int max_chain;
664 {
665 deflate_state *s;
666
667 if (deflateStateCheck(strm)) return Z_STRE
668 s = strm->state;
669 s->good_match = (uInt)good_length;
670 s->max_lazy_match = (uInt)max_lazy;
671 s->nice_match = nice_length;
672 s->max_chain_length = (uInt)max_chain;
673 return Z_OK;
674 }
675
676 /* ===========================================
677 * For the default windowBits of 15 and memLev
678 * close to exact, as well as small, upper bou
679 * is an expansion of ~0.03%, plus a small con
680 *
681 * For any setting other than those defaults f
682 * of two worst case bounds is returned. This
683 * ~13%, plus a small constant.
684 *
685 * Both the 0.03% and 4% derive from the overh
686 * one is for stored blocks of 16383 bytes (me
687 * is for stored blocks of 127 bytes (the wors
688 * expansion results from five bytes of header
689 *
690 * The larger expansion of 13% results from a
691 * the symbols buffer size (windowBits <= memL
692 * the data being compressed may have slid out
693 * a stored block from being emitted. Then the
694 * dynamic block, where a fixed block limits t
695 * per 8-bit byte, plus 10 bits for every bloc
696 * which this can occur is 255 (memLevel == 2)
697 *
698 * Shifts are used to approximate divisions, f
699 */
700 uLong ZEXPORT deflateBound(strm, sourceLen)
701 z_streamp strm;
702 uLong sourceLen;
703 {
704 deflate_state *s;
705 uLong fixedlen, storelen, wraplen;
706
707 /* upper bound for fixed blocks with 9-bit
708 (memLevel == 2, which is the lowest tha
709 ~13% overhead plus a small constant */
710 fixedlen = sourceLen + (sourceLen >> 3) +
711 (sourceLen >> 9) + 4;
712
713 /* upper bound for stored blocks with leng
714 ~4% overhead plus a small constant */
715 storelen = sourceLen + (sourceLen >> 5) +
716 (sourceLen >> 11) + 7;
717
718 /* if can't get parameters, return larger
719 if (deflateStateCheck(strm))
720 return (fixedlen > storelen ? fixedlen
721
722 /* compute wrapper length */
723 s = strm->state;
724 switch (s->wrap) {
725 case 0: /*
726 wraplen = 0;
727 break;
728 case 1: /*
729 wraplen = 6 + (s->strstart ? 4 : 0);
730 break;
731 #ifdef GZIP
732 case 2: /*
733 wraplen = 18;
734 if (s->gzhead != Z_NULL) { /*
735 Bytef *str;
736 if (s->gzhead->extra != Z_NULL)
737 wraplen += 2 + s->gzhead->extr
738 str = s->gzhead->name;
739 if (str != Z_NULL)
740 do {
741 wraplen++;
742 } while (*str++);
743 str = s->gzhead->comment;
744 if (str != Z_NULL)
745 do {
746 wraplen++;
747 } while (*str++);
748 if (s->gzhead->hcrc)
749 wraplen += 2;
750 }
751 break;
752 #endif
753 default: /*
754 wraplen = 6;
755 }
756
757 /* if not default parameters, return one o
758 if (s->w_bits != 15 || s->hash_bits != 8 +
759 return (s->w_bits <= s->hash_bits ? fi
760
761 /* default settings: return tight bound fo
762 plus a small constant */
763 return sourceLen + (sourceLen >> 12) + (so
764 (sourceLen >> 25) + 13 - 6 + wraple
765 }
766
767 /* ===========================================
768 * Put a short in the pending buffer. The 16-b
769 * IN assertion: the stream state is correct a
770 * pending_buf.
771 */
772 local void putShortMSB(s, b)
773 deflate_state *s;
774 uInt b;
775 {
776 put_byte(s, (Byte)(b >> 8));
777 put_byte(s, (Byte)(b & 0xff));
778 }
779
780 /* ===========================================
781 * Flush as much pending output as possible. A
782 * some deflate_stored() output, goes through
783 * applications may wish to modify it to avoid
784 * strm->next_out buffer and copying into it.
785 */
786 local void flush_pending(strm)
787 z_streamp strm;
788 {
789 unsigned len;
790 deflate_state *s = strm->state;
791
792 _tr_flush_bits(s);
793 len = s->pending;
794 if (len > strm->avail_out) len = strm->ava
795 if (len == 0) return;
796
797 zmemcpy(strm->next_out, s->pending_out, le
798 strm->next_out += len;
799 s->pending_out += len;
800 strm->total_out += len;
801 strm->avail_out -= len;
802 s->pending -= len;
803 if (s->pending == 0) {
804 s->pending_out = s->pending_buf;
805 }
806 }
807
808 /* ===========================================
809 * Update the header CRC with the bytes s->pen
810 */
811 #define HCRC_UPDATE(beg) \
812 do { \
813 if (s->gzhead->hcrc && s->pending > (b
814 strm->adler = crc32(strm->adler, s
815 s->pending - (
816 } while (0)
817
818 /* ===========================================
819 int ZEXPORT deflate(strm, flush)
820 z_streamp strm;
821 int flush;
822 {
823 int old_flush; /* value of flush param for
824 deflate_state *s;
825
826 if (deflateStateCheck(strm) || flush > Z_B
827 return Z_STREAM_ERROR;
828 }
829 s = strm->state;
830
831 if (strm->next_out == Z_NULL ||
832 (strm->avail_in != 0 && strm->next_in
833 (s->status == FINISH_STATE && flush !=
834 ERR_RETURN(strm, Z_STREAM_ERROR);
835 }
836 if (strm->avail_out == 0) ERR_RETURN(strm,
837
838 old_flush = s->last_flush;
839 s->last_flush = flush;
840
841 /* Flush as much pending output as possibl
842 if (s->pending != 0) {
843 flush_pending(strm);
844 if (strm->avail_out == 0) {
845 /* Since avail_out is 0, deflate w
846 * more output space, but possibly
847 * avail_in equal to zero. There w
848 * but this is not an error situat
849 * return OK instead of BUF_ERROR
850 */
851 s->last_flush = -1;
852 return Z_OK;
853 }
854
855 /* Make sure there is something to do and
856 * flushes. For repeated and useless calls
857 * returning Z_STREAM_END instead of Z_BUF
858 */
859 } else if (strm->avail_in == 0 && RANK(flu
860 flush != Z_FINISH) {
861 ERR_RETURN(strm, Z_BUF_ERROR);
862 }
863
864 /* User must not provide more input after
865 if (s->status == FINISH_STATE && strm->ava
866 ERR_RETURN(strm, Z_BUF_ERROR);
867 }
868
869 /* Write the header */
870 if (s->status == INIT_STATE && s->wrap ==
871 s->status = BUSY_STATE;
872 if (s->status == INIT_STATE) {
873 /* zlib header */
874 uInt header = (Z_DEFLATED + ((s->w_bit
875 uInt level_flags;
876
877 if (s->strategy >= Z_HUFFMAN_ONLY || s
878 level_flags = 0;
879 else if (s->level < 6)
880 level_flags = 1;
881 else if (s->level == 6)
882 level_flags = 2;
883 else
884 level_flags = 3;
885 header |= (level_flags << 6);
886 if (s->strstart != 0) header |= PRESET
887 header += 31 - (header % 31);
888
889 putShortMSB(s, header);
890
891 /* Save the adler32 of the preset dict
892 if (s->strstart != 0) {
893 putShortMSB(s, (uInt)(strm->adler
894 putShortMSB(s, (uInt)(strm->adler
895 }
896 strm->adler = adler32(0L, Z_NULL, 0);
897 s->status = BUSY_STATE;
898
899 /* Compression must start with an empt
900 flush_pending(strm);
901 if (s->pending != 0) {
902 s->last_flush = -1;
903 return Z_OK;
904 }
905 }
906 #ifdef GZIP
907 if (s->status == GZIP_STATE) {
908 /* gzip header */
909 strm->adler = crc32(0L, Z_NULL, 0);
910 put_byte(s, 31);
911 put_byte(s, 139);
912 put_byte(s, 8);
913 if (s->gzhead == Z_NULL) {
914 put_byte(s, 0);
915 put_byte(s, 0);
916 put_byte(s, 0);
917 put_byte(s, 0);
918 put_byte(s, 0);
919 put_byte(s, s->level == 9 ? 2 :
920 (s->strategy >= Z_HUFFMAN
921 4 : 0));
922 put_byte(s, OS_CODE);
923 s->status = BUSY_STATE;
924
925 /* Compression must start with an
926 flush_pending(strm);
927 if (s->pending != 0) {
928 s->last_flush = -1;
929 return Z_OK;
930 }
931 }
932 else {
933 put_byte(s, (s->gzhead->text ? 1 :
934 (s->gzhead->hcrc ? 2 : 0)
935 (s->gzhead->extra == Z_NU
936 (s->gzhead->name == Z_NUL
937 (s->gzhead->comment == Z_
938 );
939 put_byte(s, (Byte)(s->gzhead->time
940 put_byte(s, (Byte)((s->gzhead->tim
941 put_byte(s, (Byte)((s->gzhead->tim
942 put_byte(s, (Byte)((s->gzhead->tim
943 put_byte(s, s->level == 9 ? 2 :
944 (s->strategy >= Z_HUFFMAN
945 4 : 0));
946 put_byte(s, s->gzhead->os & 0xff);
947 if (s->gzhead->extra != Z_NULL) {
948 put_byte(s, s->gzhead->extra_l
949 put_byte(s, (s->gzhead->extra_
950 }
951 if (s->gzhead->hcrc)
952 strm->adler = crc32(strm->adle
953 s->pending
954 s->gzindex = 0;
955 s->status = EXTRA_STATE;
956 }
957 }
958 if (s->status == EXTRA_STATE) {
959 if (s->gzhead->extra != Z_NULL) {
960 ulg beg = s->pending; /* start o
961 uInt left = (s->gzhead->extra_len
962 while (s->pending + left > s->pend
963 uInt copy = s->pending_buf_siz
964 zmemcpy(s->pending_buf + s->pe
965 s->gzhead->extra + s->
966 s->pending = s->pending_buf_si
967 HCRC_UPDATE(beg);
968 s->gzindex += copy;
969 flush_pending(strm);
970 if (s->pending != 0) {
971 s->last_flush = -1;
972 return Z_OK;
973 }
974 beg = 0;
975 left -= copy;
976 }
977 zmemcpy(s->pending_buf + s->pendin
978 s->gzhead->extra + s->gzin
979 s->pending += left;
980 HCRC_UPDATE(beg);
981 s->gzindex = 0;
982 }
983 s->status = NAME_STATE;
984 }
985 if (s->status == NAME_STATE) {
986 if (s->gzhead->name != Z_NULL) {
987 ulg beg = s->pending; /* start o
988 int val;
989 do {
990 if (s->pending == s->pending_b
991 HCRC_UPDATE(beg);
992 flush_pending(strm);
993 if (s->pending != 0) {
994 s->last_flush = -1;
995 return Z_OK;
996 }
997 beg = 0;
998 }
999 val = s->gzhead->name[s->gzind
1000 put_byte(s, val);
1001 } while (val != 0);
1002 HCRC_UPDATE(beg);
1003 s->gzindex = 0;
1004 }
1005 s->status = COMMENT_STATE;
1006 }
1007 if (s->status == COMMENT_STATE) {
1008 if (s->gzhead->comment != Z_NULL) {
1009 ulg beg = s->pending; /* start
1010 int val;
1011 do {
1012 if (s->pending == s->pending_
1013 HCRC_UPDATE(beg);
1014 flush_pending(strm);
1015 if (s->pending != 0) {
1016 s->last_flush = -1;
1017 return Z_OK;
1018 }
1019 beg = 0;
1020 }
1021 val = s->gzhead->comment[s->g
1022 put_byte(s, val);
1023 } while (val != 0);
1024 HCRC_UPDATE(beg);
1025 }
1026 s->status = HCRC_STATE;
1027 }
1028 if (s->status == HCRC_STATE) {
1029 if (s->gzhead->hcrc) {
1030 if (s->pending + 2 > s->pending_b
1031 flush_pending(strm);
1032 if (s->pending != 0) {
1033 s->last_flush = -1;
1034 return Z_OK;
1035 }
1036 }
1037 put_byte(s, (Byte)(strm->adler &
1038 put_byte(s, (Byte)((strm->adler >
1039 strm->adler = crc32(0L, Z_NULL, 0
1040 }
1041 s->status = BUSY_STATE;
1042
1043 /* Compression must start with an emp
1044 flush_pending(strm);
1045 if (s->pending != 0) {
1046 s->last_flush = -1;
1047 return Z_OK;
1048 }
1049 }
1050 #endif
1051
1052 /* Start a new block or continue the curr
1053 */
1054 if (strm->avail_in != 0 || s->lookahead !
1055 (flush != Z_NO_FLUSH && s->status !=
1056 block_state bstate;
1057
1058 bstate = s->level == 0 ? deflate_stor
1059 s->strategy == Z_HUFFMAN_ONL
1060 s->strategy == Z_RLE ? defla
1061 (*(configuration_table[s->le
1062
1063 if (bstate == finish_started || bstat
1064 s->status = FINISH_STATE;
1065 }
1066 if (bstate == need_more || bstate ==
1067 if (strm->avail_out == 0) {
1068 s->last_flush = -1; /* avoid
1069 }
1070 return Z_OK;
1071 /* If flush != Z_NO_FLUSH && avai
1072 * of deflate should use the same
1073 * that the flush is complete. So
1074 * empty block here, this will be
1075 * ensures that for a very small
1076 * one empty block.
1077 */
1078 }
1079 if (bstate == block_done) {
1080 if (flush == Z_PARTIAL_FLUSH) {
1081 _tr_align(s);
1082 } else if (flush != Z_BLOCK) { /*
1083 _tr_stored_block(s, (char*)0,
1084 /* For a full flush, this emp
1085 * as a special marker by inf
1086 */
1087 if (flush == Z_FULL_FLUSH) {
1088 CLEAR_HASH(s);
1089 if (s->lookahead == 0) {
1090 s->strstart = 0;
1091 s->block_start = 0L;
1092 s->insert = 0;
1093 }
1094 }
1095 }
1096 flush_pending(strm);
1097 if (strm->avail_out == 0) {
1098 s->last_flush = -1; /* avoid BU
1099 return Z_OK;
1100 }
1101 }
1102 }
1103
1104 if (flush != Z_FINISH) return Z_OK;
1105 if (s->wrap <= 0) return Z_STREAM_END;
1106
1107 /* Write the trailer */
1108 #ifdef GZIP
1109 if (s->wrap == 2) {
1110 put_byte(s, (Byte)(strm->adler & 0xff
1111 put_byte(s, (Byte)((strm->adler >> 8)
1112 put_byte(s, (Byte)((strm->adler >> 16
1113 put_byte(s, (Byte)((strm->adler >> 24
1114 put_byte(s, (Byte)(strm->total_in & 0
1115 put_byte(s, (Byte)((strm->total_in >>
1116 put_byte(s, (Byte)((strm->total_in >>
1117 put_byte(s, (Byte)((strm->total_in >>
1118 }
1119 else
1120 #endif
1121 {
1122 putShortMSB(s, (uInt)(strm->adler >>
1123 putShortMSB(s, (uInt)(strm->adler & 0
1124 }
1125 flush_pending(strm);
1126 /* If avail_out is zero, the application
1127 * to flush the rest.
1128 */
1129 if (s->wrap > 0) s->wrap = -s->wrap; /* w
1130 return s->pending != 0 ? Z_OK : Z_STREAM_
1131 }
1132
1133 /* ==========================================
1134 int ZEXPORT deflateEnd(strm)
1135 z_streamp strm;
1136 {
1137 int status;
1138
1139 if (deflateStateCheck(strm)) return Z_STR
1140
1141 status = strm->state->status;
1142
1143 /* Deallocate in reverse order of allocat
1144 TRY_FREE(strm, strm->state->pending_buf);
1145 TRY_FREE(strm, strm->state->head);
1146 TRY_FREE(strm, strm->state->prev);
1147 TRY_FREE(strm, strm->state->window);
1148
1149 ZFREE(strm, strm->state);
1150 strm->state = Z_NULL;
1151
1152 return status == BUSY_STATE ? Z_DATA_ERRO
1153 }
1154
1155 /* ==========================================
1156 * Copy the source state to the destination s
1157 * To simplify the source, this is not suppor
1158 * doesn't have enough memory anyway to dupli
1159 */
1160 int ZEXPORT deflateCopy(dest, source)
1161 z_streamp dest;
1162 z_streamp source;
1163 {
1164 #ifdef MAXSEG_64K
1165 return Z_STREAM_ERROR;
1166 #else
1167 deflate_state *ds;
1168 deflate_state *ss;
1169
1170
1171 if (deflateStateCheck(source) || dest ==
1172 return Z_STREAM_ERROR;
1173 }
1174
1175 ss = source->state;
1176
1177 zmemcpy((voidpf)dest, (voidpf)source, siz
1178
1179 ds = (deflate_state *) ZALLOC(dest, 1, si
1180 if (ds == Z_NULL) return Z_MEM_ERROR;
1181 dest->state = (struct internal_state FAR
1182 zmemcpy((voidpf)ds, (voidpf)ss, sizeof(de
1183 ds->strm = dest;
1184
1185 ds->window = (Bytef *) ZALLOC(dest, ds->w
1186 ds->prev = (Posf *) ZALLOC(dest, ds->w
1187 ds->head = (Posf *) ZALLOC(dest, ds->h
1188 ds->pending_buf = (uchf *) ZALLOC(dest, d
1189
1190 if (ds->window == Z_NULL || ds->prev == Z
1191 ds->pending_buf == Z_NULL) {
1192 deflateEnd (dest);
1193 return Z_MEM_ERROR;
1194 }
1195 /* following zmemcpy do not work for 16-b
1196 zmemcpy(ds->window, ss->window, ds->w_siz
1197 zmemcpy((voidpf)ds->prev, (voidpf)ss->pre
1198 zmemcpy((voidpf)ds->head, (voidpf)ss->hea
1199 zmemcpy(ds->pending_buf, ss->pending_buf,
1200
1201 ds->pending_out = ds->pending_buf + (ss->
1202 ds->sym_buf = ds->pending_buf + ds->lit_b
1203
1204 ds->l_desc.dyn_tree = ds->dyn_ltree;
1205 ds->d_desc.dyn_tree = ds->dyn_dtree;
1206 ds->bl_desc.dyn_tree = ds->bl_tree;
1207
1208 return Z_OK;
1209 #endif /* MAXSEG_64K */
1210 }
1211
1212 /* ==========================================
1213 * Read a new buffer from the current input s
1214 * and total number of bytes read. All defla
1215 * this function so some applications may wis
1216 * allocating a large strm->next_in buffer an
1217 * (See also flush_pending()).
1218 */
1219 local unsigned read_buf(strm, buf, size)
1220 z_streamp strm;
1221 Bytef *buf;
1222 unsigned size;
1223 {
1224 unsigned len = strm->avail_in;
1225
1226 if (len > size) len = size;
1227 if (len == 0) return 0;
1228
1229 strm->avail_in -= len;
1230
1231 zmemcpy(buf, strm->next_in, len);
1232 if (strm->state->wrap == 1) {
1233 strm->adler = adler32(strm->adler, bu
1234 }
1235 #ifdef GZIP
1236 else if (strm->state->wrap == 2) {
1237 strm->adler = crc32(strm->adler, buf,
1238 }
1239 #endif
1240 strm->next_in += len;
1241 strm->total_in += len;
1242
1243 return len;
1244 }
1245
1246 /* ==========================================
1247 * Initialize the "longest match" routines fo
1248 */
1249 local void lm_init(s)
1250 deflate_state *s;
1251 {
1252 s->window_size = (ulg)2L*s->w_size;
1253
1254 CLEAR_HASH(s);
1255
1256 /* Set the default configuration paramete
1257 */
1258 s->max_lazy_match = configuration_table
1259 s->good_match = configuration_table
1260 s->nice_match = configuration_table
1261 s->max_chain_length = configuration_table
1262
1263 s->strstart = 0;
1264 s->block_start = 0L;
1265 s->lookahead = 0;
1266 s->insert = 0;
1267 s->match_length = s->prev_length = MIN_MA
1268 s->match_available = 0;
1269 s->ins_h = 0;
1270 }
1271
1272 #ifndef FASTEST
1273 /* ==========================================
1274 * Set match_start to the longest match start
1275 * return its length. Matches shorter or equa
1276 * in which case the result is equal to prev_
1277 * garbage.
1278 * IN assertions: cur_match is the head of th
1279 * string (strstart) and its distance is <=
1280 * OUT assertion: the match length is not gre
1281 */
1282 local uInt longest_match(s, cur_match)
1283 deflate_state *s;
1284 IPos cur_match;
1285 {
1286 unsigned chain_length = s->max_chain_leng
1287 register Bytef *scan = s->window + s->str
1288 register Bytef *match;
1289 register int len;
1290 int best_len = (int)s->prev_length;
1291 int nice_match = s->nice_match;
1292 IPos limit = s->strstart > (IPos)MAX_DIST
1293 s->strstart - (IPos)MAX_DIST(s) : NIL
1294 /* Stop when cur_match becomes <= limit.
1295 * we prevent matches with the string of
1296 */
1297 Posf *prev = s->prev;
1298 uInt wmask = s->w_mask;
1299
1300 #ifdef UNALIGNED_OK
1301 /* Compare two bytes at a time. Note: thi
1302 * Try with and without -DUNALIGNED_OK to
1303 */
1304 register Bytef *strend = s->window + s->s
1305 register ush scan_start = *(ushf*)scan;
1306 register ush scan_end = *(ushf*)(scan +
1307 #else
1308 register Bytef *strend = s->window + s->s
1309 register Byte scan_end1 = scan[best_len
1310 register Byte scan_end = scan[best_len]
1311 #endif
1312
1313 /* The code is optimized for HASH_BITS >=
1314 * It is easy to get rid of this optimiza
1315 */
1316 Assert(s->hash_bits >= 8 && MAX_MATCH ==
1317
1318 /* Do not waste too much time if we alrea
1319 if (s->prev_length >= s->good_match) {
1320 chain_length >>= 2;
1321 }
1322 /* Do not look for matches beyond the end
1323 * to make deflate deterministic.
1324 */
1325 if ((uInt)nice_match > s->lookahead) nice
1326
1327 Assert((ulg)s->strstart <= s->window_size
1328 "need lookahead");
1329
1330 do {
1331 Assert(cur_match < s->strstart, "no f
1332 match = s->window + cur_match;
1333
1334 /* Skip to next match if the match le
1335 * or if the match length is less tha
1336 * for insufficient lookahead only oc
1337 * reasons. Therefore uninitialized
1338 * conditional jumps will be made tha
1339 * However the length of the match is
1340 * the output of deflate is not affec
1341 */
1342 #if (defined(UNALIGNED_OK) && MAX_MATCH == 25
1343 /* This code assumes sizeof(unsigned
1344 * UNALIGNED_OK if your compiler uses
1345 */
1346 if (*(ushf*)(match + best_len - 1) !=
1347 *(ushf*)match != scan_start) cont
1348
1349 /* It is not necessary to compare sca
1350 * always equal when the other bytes
1351 * are equal and that HASH_BITS >= 8.
1352 * strstart + 3, + 5, up to strstart
1353 * lookahead only every 4th compariso
1354 * at strstart + 257. If MAX_MATCH-2
1355 * necessary to put more guard bytes
1356 * to check more often for insufficie
1357 */
1358 Assert(scan[2] == match[2], "scan[2]?
1359 scan++, match++;
1360 do {
1361 } while (*(ushf*)(scan += 2) == *(ush
1362 *(ushf*)(scan += 2) == *(ush
1363 *(ushf*)(scan += 2) == *(ush
1364 *(ushf*)(scan += 2) == *(ush
1365 scan < strend);
1366 /* The funny "do {}" generates better
1367
1368 /* Here, scan <= window + strstart +
1369 Assert(scan <= s->window + (unsigned)
1370 "wild scan");
1371 if (*scan == *match) scan++;
1372
1373 len = (MAX_MATCH - 1) - (int)(strend
1374 scan = strend - (MAX_MATCH-1);
1375
1376 #else /* UNALIGNED_OK */
1377
1378 if (match[best_len] != scan_end
1379 match[best_len - 1] != scan_end1
1380 *match != *scan
1381 *++match != scan[1])
1382
1383 /* The check at best_len - 1 can be r
1384 * again later. (This heuristic is no
1385 * It is not necessary to compare sca
1386 * are always equal when the other by
1387 * the hash keys are equal and that H
1388 */
1389 scan += 2, match++;
1390 Assert(*scan == *match, "match[2]?");
1391
1392 /* We check for insufficient lookahea
1393 * the 256th check will be made at st
1394 */
1395 do {
1396 } while (*++scan == *++match && *++sc
1397 *++scan == *++match && *++sc
1398 *++scan == *++match && *++sc
1399 *++scan == *++match && *++sc
1400 scan < strend);
1401
1402 Assert(scan <= s->window + (unsigned)
1403 "wild scan");
1404
1405 len = MAX_MATCH - (int)(strend - scan
1406 scan = strend - MAX_MATCH;
1407
1408 #endif /* UNALIGNED_OK */
1409
1410 if (len > best_len) {
1411 s->match_start = cur_match;
1412 best_len = len;
1413 if (len >= nice_match) break;
1414 #ifdef UNALIGNED_OK
1415 scan_end = *(ushf*)(scan + best_l
1416 #else
1417 scan_end1 = scan[best_len - 1];
1418 scan_end = scan[best_len];
1419 #endif
1420 }
1421 } while ((cur_match = prev[cur_match & wm
1422 && --chain_length != 0);
1423
1424 if ((uInt)best_len <= s->lookahead) retur
1425 return s->lookahead;
1426 }
1427
1428 #else /* FASTEST */
1429
1430 /* ------------------------------------------
1431 * Optimized version for FASTEST only
1432 */
1433 local uInt longest_match(s, cur_match)
1434 deflate_state *s;
1435 IPos cur_match;
1436 {
1437 register Bytef *scan = s->window + s->str
1438 register Bytef *match;
1439 register int len;
1440 register Bytef *strend = s->window + s->s
1441
1442 /* The code is optimized for HASH_BITS >=
1443 * It is easy to get rid of this optimiza
1444 */
1445 Assert(s->hash_bits >= 8 && MAX_MATCH ==
1446
1447 Assert((ulg)s->strstart <= s->window_size
1448 "need lookahead");
1449
1450 Assert(cur_match < s->strstart, "no futur
1451
1452 match = s->window + cur_match;
1453
1454 /* Return failure if the match length is
1455 */
1456 if (match[0] != scan[0] || match[1] != sc
1457
1458 /* The check at best_len - 1 can be remov
1459 * again later. (This heuristic is not al
1460 * It is not necessary to compare scan[2]
1461 * are always equal when the other bytes
1462 * the hash keys are equal and that HASH_
1463 */
1464 scan += 2, match += 2;
1465 Assert(*scan == *match, "match[2]?");
1466
1467 /* We check for insufficient lookahead on
1468 * the 256th check will be made at strsta
1469 */
1470 do {
1471 } while (*++scan == *++match && *++scan =
1472 *++scan == *++match && *++scan =
1473 *++scan == *++match && *++scan =
1474 *++scan == *++match && *++scan =
1475 scan < strend);
1476
1477 Assert(scan <= s->window + (unsigned)(s->
1478
1479 len = MAX_MATCH - (int)(strend - scan);
1480
1481 if (len < MIN_MATCH) return MIN_MATCH - 1
1482
1483 s->match_start = cur_match;
1484 return (uInt)len <= s->lookahead ? (uInt)
1485 }
1486
1487 #endif /* FASTEST */
1488
1489 #ifdef ZLIB_DEBUG
1490
1491 #define EQUAL 0
1492 /* result of memcmp for equal strings */
1493
1494 /* ==========================================
1495 * Check that the match at match_start is ind
1496 */
1497 local void check_match(s, start, match, lengt
1498 deflate_state *s;
1499 IPos start, match;
1500 int length;
1501 {
1502 /* check that the match is indeed a match
1503 if (zmemcmp(s->window + match,
1504 s->window + start, length) !=
1505 fprintf(stderr, " start %u, match %u,
1506 start, match, length);
1507 do {
1508 fprintf(stderr, "%c%c", s->window
1509 } while (--length != 0);
1510 z_error("invalid match");
1511 }
1512 if (z_verbose > 1) {
1513 fprintf(stderr,"\\[%d,%d]", start - m
1514 do { putc(s->window[start++], stderr)
1515 }
1516 }
1517 #else
1518 # define check_match(s, start, match, length
1519 #endif /* ZLIB_DEBUG */
1520
1521 /* ==========================================
1522 * Fill the window when the lookahead becomes
1523 * Updates strstart and lookahead.
1524 *
1525 * IN assertion: lookahead < MIN_LOOKAHEAD
1526 * OUT assertions: strstart <= window_size-MI
1527 * At least one byte has been read, or ava
1528 * performed for at least two bytes (requi
1529 * option -- not supported here).
1530 */
1531 local void fill_window(s)
1532 deflate_state *s;
1533 {
1534 unsigned n;
1535 unsigned more; /* Amount of free space
1536 uInt wsize = s->w_size;
1537
1538 Assert(s->lookahead < MIN_LOOKAHEAD, "alr
1539
1540 do {
1541 more = (unsigned)(s->window_size -(ul
1542
1543 /* Deal with !@#$% 64K limit: */
1544 if (sizeof(int) <= 2) {
1545 if (more == 0 && s->strstart == 0
1546 more = wsize;
1547
1548 } else if (more == (unsigned)(-1)
1549 /* Very unlikely, but possibl
1550 * strstart == 0 && lookahead
1551 */
1552 more--;
1553 }
1554 }
1555
1556 /* If the window is almost full and t
1557 * move the upper half to the lower o
1558 */
1559 if (s->strstart >= wsize + MAX_DIST(s
1560
1561 zmemcpy(s->window, s->window + ws
1562 s->match_start -= wsize;
1563 s->strstart -= wsize; /* we no
1564 s->block_start -= (long) wsize;
1565 if (s->insert > s->strstart)
1566 s->insert = s->strstart;
1567 slide_hash(s);
1568 more += wsize;
1569 }
1570 if (s->strm->avail_in == 0) break;
1571
1572 /* If there was no sliding:
1573 * strstart <= WSIZE+MAX_DIST-1 &&
1574 * more == window_size - lookahead
1575 * => more >= window_size - (MIN_LOOK
1576 * => more >= window_size - 2*WSIZE +
1577 * In the BIG_MEM or MMAP case (not y
1578 * window_size == input_size + MIN_
1579 * strstart + s->lookahead <= input
1580 * Otherwise, window_size == 2*WSIZE
1581 * If there was sliding, more >= WSIZ
1582 */
1583 Assert(more >= 2, "more < 2");
1584
1585 n = read_buf(s->strm, s->window + s->
1586 s->lookahead += n;
1587
1588 /* Initialize the hash value now that
1589 if (s->lookahead + s->insert >= MIN_M
1590 uInt str = s->strstart - s->inser
1591 s->ins_h = s->window[str];
1592 UPDATE_HASH(s, s->ins_h, s->windo
1593 #if MIN_MATCH != 3
1594 Call UPDATE_HASH() MIN_MATCH-3 mo
1595 #endif
1596 while (s->insert) {
1597 UPDATE_HASH(s, s->ins_h, s->w
1598 #ifndef FASTEST
1599 s->prev[str & s->w_mask] = s-
1600 #endif
1601 s->head[s->ins_h] = (Pos)str;
1602 str++;
1603 s->insert--;
1604 if (s->lookahead + s->insert
1605 break;
1606 }
1607 }
1608 /* If the whole input has less than M
1609 * but this is not important since on
1610 */
1611
1612 } while (s->lookahead < MIN_LOOKAHEAD &&
1613
1614 /* If the WIN_INIT bytes after the end of
1615 * written, then zero those bytes in orde
1616 * the use of uninitialized (or uninitial
1617 * the longest match routines. Update th
1618 * time through here. WIN_INIT is set to
1619 * routines allow scanning to strstart +
1620 */
1621 if (s->high_water < s->window_size) {
1622 ulg curr = s->strstart + (ulg)(s->loo
1623 ulg init;
1624
1625 if (s->high_water < curr) {
1626 /* Previous high water mark below
1627 * bytes or up to end of window,
1628 */
1629 init = s->window_size - curr;
1630 if (init > WIN_INIT)
1631 init = WIN_INIT;
1632 zmemzero(s->window + curr, (unsig
1633 s->high_water = curr + init;
1634 }
1635 else if (s->high_water < (ulg)curr +
1636 /* High water mark at or above cu
1637 * plus WIN_INIT -- zero out to c
1638 * to end of window, whichever is
1639 */
1640 init = (ulg)curr + WIN_INIT - s->
1641 if (init > s->window_size - s->hi
1642 init = s->window_size - s->hi
1643 zmemzero(s->window + s->high_wate
1644 s->high_water += init;
1645 }
1646 }
1647
1648 Assert((ulg)s->strstart <= s->window_size
1649 "not enough room for search");
1650 }
1651
1652 /* ==========================================
1653 * Flush the current block, with given end-of
1654 * IN assertion: strstart is set to the end o
1655 */
1656 #define FLUSH_BLOCK_ONLY(s, last) { \
1657 _tr_flush_block(s, (s->block_start >= 0L ?
1658 (charf *)&s->window[(unsig
1659 (charf *)Z_NULL), \
1660 (ulg)((long)s->strstart - s->
1661 (last)); \
1662 s->block_start = s->strstart; \
1663 flush_pending(s->strm); \
1664 Tracev((stderr,"[FLUSH]")); \
1665 }
1666
1667 /* Same but force premature exit if necessary
1668 #define FLUSH_BLOCK(s, last) { \
1669 FLUSH_BLOCK_ONLY(s, last); \
1670 if (s->strm->avail_out == 0) return (last)
1671 }
1672
1673 /* Maximum stored block length in deflate for
1674 #define MAX_STORED 65535
1675
1676 /* Minimum of a and b. */
1677 #define MIN(a, b) ((a) > (b) ? (b) : (a))
1678
1679 /* ==========================================
1680 * Copy without compression as much as possib
1681 * the current block state.
1682 *
1683 * In case deflateParams() is used to later s
1684 * level, s->matches (otherwise unused when s
1685 * of hash table slides to perform. If s->mat
1686 * slide will be done when switching. If s->m
1687 * allowed here, then the hash table will be
1688 * is the same as a clear.
1689 *
1690 * deflate_stored() is written to minimize th
1691 * copied. It is most efficient with large in
1692 * maximizes the opportunities to have a sing
1693 */
1694 local block_state deflate_stored(s, flush)
1695 deflate_state *s;
1696 int flush;
1697 {
1698 /* Smallest worthy block size when not fl
1699 * this is 32K. This can be as small as 5
1700 * large input and output buffers, the st
1701 */
1702 unsigned min_block = MIN(s->pending_buf_s
1703
1704 /* Copy as many min_block or larger store
1705 * possible. If flushing, copy the remain
1706 * stored blocks, if there is enough spac
1707 */
1708 unsigned len, left, have, last = 0;
1709 unsigned used = s->strm->avail_in;
1710 do {
1711 /* Set len to the maximum size block
1712 * available input data and output sp
1713 * would be copied from what's left i
1714 */
1715 len = MAX_STORED; /* maximum de
1716 have = (s->bi_valid + 42) >> 3;
1717 if (s->strm->avail_out < have)
1718 break;
1719 /* maximum stored block length th
1720 have = s->strm->avail_out - have;
1721 left = s->strstart - s->block_start;
1722 if (len > (ulg)left + s->strm->avail_
1723 len = left + s->strm->avail_in;
1724 if (len > have)
1725 len = have;
1726
1727 /* If the stored block would be less
1728 * unable to copy all of the availabl
1729 * copying to the window and the pend
1730 * write an empty block when flushing
1731 */
1732 if (len < min_block && ((len == 0 &&
1733 flush == Z_NO
1734 len != left +
1735 break;
1736
1737 /* Make a dummy stored block in pendi
1738 * including any pending bits. This a
1739 */
1740 last = flush == Z_FINISH && len == le
1741 _tr_stored_block(s, (char *)0, 0L, la
1742
1743 /* Replace the lengths in the dummy s
1744 s->pending_buf[s->pending - 4] = len;
1745 s->pending_buf[s->pending - 3] = len
1746 s->pending_buf[s->pending - 2] = ~len
1747 s->pending_buf[s->pending - 1] = ~len
1748
1749 /* Write the stored block header byte
1750 flush_pending(s->strm);
1751
1752 #ifdef ZLIB_DEBUG
1753 /* Update debugging counts for the da
1754 s->compressed_len += len << 3;
1755 s->bits_sent += len << 3;
1756 #endif
1757
1758 /* Copy uncompressed bytes from the w
1759 if (left) {
1760 if (left > len)
1761 left = len;
1762 zmemcpy(s->strm->next_out, s->win
1763 s->strm->next_out += left;
1764 s->strm->avail_out -= left;
1765 s->strm->total_out += left;
1766 s->block_start += left;
1767 len -= left;
1768 }
1769
1770 /* Copy uncompressed bytes directly f
1771 * the check value.
1772 */
1773 if (len) {
1774 read_buf(s->strm, s->strm->next_o
1775 s->strm->next_out += len;
1776 s->strm->avail_out -= len;
1777 s->strm->total_out += len;
1778 }
1779 } while (last == 0);
1780
1781 /* Update the sliding window with the las
1782 * data, or append all of the copied data
1783 * than s->w_size bytes were copied. Also
1784 * insert in the hash tables, in the even
1785 * a non-zero compression level.
1786 */
1787 used -= s->strm->avail_in; /* number
1788 if (used) {
1789 /* If any input was used, then no unu
1790 * therefore s->block_start == s->str
1791 */
1792 if (used >= s->w_size) { /* suppla
1793 s->matches = 2; /* clear
1794 zmemcpy(s->window, s->strm->next_
1795 s->strstart = s->w_size;
1796 s->insert = s->strstart;
1797 }
1798 else {
1799 if (s->window_size - s->strstart
1800 /* Slide the window down. */
1801 s->strstart -= s->w_size;
1802 zmemcpy(s->window, s->window
1803 if (s->matches < 2)
1804 s->matches++; /* add a
1805 if (s->insert > s->strstart)
1806 s->insert = s->strstart;
1807 }
1808 zmemcpy(s->window + s->strstart,
1809 s->strstart += used;
1810 s->insert += MIN(used, s->w_size
1811 }
1812 s->block_start = s->strstart;
1813 }
1814 if (s->high_water < s->strstart)
1815 s->high_water = s->strstart;
1816
1817 /* If the last block was written to next_
1818 if (last)
1819 return finish_done;
1820
1821 /* If flushing and all input has been con
1822 if (flush != Z_NO_FLUSH && flush != Z_FIN
1823 s->strm->avail_in == 0 && (long)s->st
1824 return block_done;
1825
1826 /* Fill the window with any remaining inp
1827 have = s->window_size - s->strstart;
1828 if (s->strm->avail_in > have && s->block_
1829 /* Slide the window down. */
1830 s->block_start -= s->w_size;
1831 s->strstart -= s->w_size;
1832 zmemcpy(s->window, s->window + s->w_s
1833 if (s->matches < 2)
1834 s->matches++; /* add a
1835 have += s->w_size; /* more s
1836 if (s->insert > s->strstart)
1837 s->insert = s->strstart;
1838 }
1839 if (have > s->strm->avail_in)
1840 have = s->strm->avail_in;
1841 if (have) {
1842 read_buf(s->strm, s->window + s->strs
1843 s->strstart += have;
1844 s->insert += MIN(have, s->w_size - s-
1845 }
1846 if (s->high_water < s->strstart)
1847 s->high_water = s->strstart;
1848
1849 /* There was not enough avail_out to writ
1850 * stored block to next_out. Write a stor
1851 * have enough input for a worthy block,
1852 * room for the remaining input as a stor
1853 */
1854 have = (s->bi_valid + 42) >> 3; /
1855 /* maximum stored block length that w
1856 have = MIN(s->pending_buf_size - have, MA
1857 min_block = MIN(have, s->w_size);
1858 left = s->strstart - s->block_start;
1859 if (left >= min_block ||
1860 ((left || flush == Z_FINISH) && flush
1861 s->strm->avail_in == 0 && left <= ha
1862 len = MIN(left, have);
1863 last = flush == Z_FINISH && s->strm->
1864 len == left ? 1 : 0;
1865 _tr_stored_block(s, (charf *)s->windo
1866 s->block_start += len;
1867 flush_pending(s->strm);
1868 }
1869
1870 /* We've done all we can with the availab
1871 return last ? finish_started : need_more;
1872 }
1873
1874 /* ==========================================
1875 * Compress as much as possible from the inpu
1876 * block state.
1877 * This function does not perform lazy evalua
1878 * new strings in the dictionary only for unm
1879 * matches. It is used only for the fast comp
1880 */
1881 local block_state deflate_fast(s, flush)
1882 deflate_state *s;
1883 int flush;
1884 {
1885 IPos hash_head; /* head of the hash
1886 int bflush; /* set if current b
1887
1888 for (;;) {
1889 /* Make sure that we always have enou
1890 * at the end of the input file. We n
1891 * for the next match, plus MIN_MATCH
1892 * string following the next match.
1893 */
1894 if (s->lookahead < MIN_LOOKAHEAD) {
1895 fill_window(s);
1896 if (s->lookahead < MIN_LOOKAHEAD
1897 return need_more;
1898 }
1899 if (s->lookahead == 0) break; /*
1900 }
1901
1902 /* Insert the string window[strstart
1903 * dictionary, and set hash_head to t
1904 */
1905 hash_head = NIL;
1906 if (s->lookahead >= MIN_MATCH) {
1907 INSERT_STRING(s, s->strstart, has
1908 }
1909
1910 /* Find the longest match, discarding
1911 * At this point we have always match
1912 */
1913 if (hash_head != NIL && s->strstart -
1914 /* To simplify the code, we preve
1915 * of window index 0 (in particul
1916 * of the string with itself at t
1917 */
1918 s->match_length = longest_match (
1919 /* longest_match() sets match_sta
1920 }
1921 if (s->match_length >= MIN_MATCH) {
1922 check_match(s, s->strstart, s->ma
1923
1924 _tr_tally_dist(s, s->strstart - s
1925 s->match_length -
1926
1927 s->lookahead -= s->match_length;
1928
1929 /* Insert new strings in the hash
1930 * is not too large. This saves t
1931 */
1932 #ifndef FASTEST
1933 if (s->match_length <= s->max_ins
1934 s->lookahead >= MIN_MATCH) {
1935 s->match_length--; /* string
1936 do {
1937 s->strstart++;
1938 INSERT_STRING(s, s->strst
1939 /* strstart never exceeds
1940 * always MIN_MATCH bytes
1941 */
1942 } while (--s->match_length !=
1943 s->strstart++;
1944 } else
1945 #endif
1946 {
1947 s->strstart += s->match_lengt
1948 s->match_length = 0;
1949 s->ins_h = s->window[s->strst
1950 UPDATE_HASH(s, s->ins_h, s->w
1951 #if MIN_MATCH != 3
1952 Call UPDATE_HASH() MIN_MATCH-
1953 #endif
1954 /* If lookahead < MIN_MATCH,
1955 * matter since it will be re
1956 */
1957 }
1958 } else {
1959 /* No match, output a literal byt
1960 Tracevv((stderr,"%c", s->window[s
1961 _tr_tally_lit(s, s->window[s->str
1962 s->lookahead--;
1963 s->strstart++;
1964 }
1965 if (bflush) FLUSH_BLOCK(s, 0);
1966 }
1967 s->insert = s->strstart < MIN_MATCH-1 ? s
1968 if (flush == Z_FINISH) {
1969 FLUSH_BLOCK(s, 1);
1970 return finish_done;
1971 }
1972 if (s->sym_next)
1973 FLUSH_BLOCK(s, 0);
1974 return block_done;
1975 }
1976
1977 #ifndef FASTEST
1978 /* ==========================================
1979 * Same as above, but achieves better compres
1980 * evaluation for matches: a match is finally
1981 * no better match at the next window positio
1982 */
1983 local block_state deflate_slow(s, flush)
1984 deflate_state *s;
1985 int flush;
1986 {
1987 IPos hash_head; /* head of hash
1988 int bflush; /* set if curren
1989
1990 /* Process the input block. */
1991 for (;;) {
1992 /* Make sure that we always have enou
1993 * at the end of the input file. We n
1994 * for the next match, plus MIN_MATCH
1995 * string following the next match.
1996 */
1997 if (s->lookahead < MIN_LOOKAHEAD) {
1998 fill_window(s);
1999 if (s->lookahead < MIN_LOOKAHEAD
2000 return need_more;
2001 }
2002 if (s->lookahead == 0) break; /*
2003 }
2004
2005 /* Insert the string window[strstart
2006 * dictionary, and set hash_head to t
2007 */
2008 hash_head = NIL;
2009 if (s->lookahead >= MIN_MATCH) {
2010 INSERT_STRING(s, s->strstart, has
2011 }
2012
2013 /* Find the longest match, discarding
2014 */
2015 s->prev_length = s->match_length, s->
2016 s->match_length = MIN_MATCH-1;
2017
2018 if (hash_head != NIL && s->prev_lengt
2019 s->strstart - hash_head <= MAX_DI
2020 /* To simplify the code, we preve
2021 * of window index 0 (in particul
2022 * of the string with itself at t
2023 */
2024 s->match_length = longest_match (
2025 /* longest_match() sets match_sta
2026
2027 if (s->match_length <= 5 && (s->s
2028 #if TOO_FAR <= 32767
2029 || (s->match_length == MIN_MA
2030 s->strstart - s->match_st
2031 #endif
2032 )) {
2033
2034 /* If prev_match is also MIN_
2035 * but we will ignore the cur
2036 */
2037 s->match_length = MIN_MATCH-1
2038 }
2039 }
2040 /* If there was a match at the previo
2041 * match is not better, output the pr
2042 */
2043 if (s->prev_length >= MIN_MATCH && s-
2044 uInt max_insert = s->strstart + s
2045 /* Do not insert strings in hash
2046
2047 check_match(s, s->strstart - 1, s
2048
2049 _tr_tally_dist(s, s->strstart - 1
2050 s->prev_length - M
2051
2052 /* Insert in hash table all strin
2053 * strstart - 1 and strstart are
2054 * enough lookahead, the last two
2055 * the hash table.
2056 */
2057 s->lookahead -= s->prev_length -
2058 s->prev_length -= 2;
2059 do {
2060 if (++s->strstart <= max_inse
2061 INSERT_STRING(s, s->strst
2062 }
2063 } while (--s->prev_length != 0);
2064 s->match_available = 0;
2065 s->match_length = MIN_MATCH-1;
2066 s->strstart++;
2067
2068 if (bflush) FLUSH_BLOCK(s, 0);
2069
2070 } else if (s->match_available) {
2071 /* If there was no match at the p
2072 * single literal. If there was a
2073 * is longer, truncate the previo
2074 */
2075 Tracevv((stderr,"%c", s->window[s
2076 _tr_tally_lit(s, s->window[s->str
2077 if (bflush) {
2078 FLUSH_BLOCK_ONLY(s, 0);
2079 }
2080 s->strstart++;
2081 s->lookahead--;
2082 if (s->strm->avail_out == 0) retu
2083 } else {
2084 /* There is no previous match to
2085 * the next step to decide.
2086 */
2087 s->match_available = 1;
2088 s->strstart++;
2089 s->lookahead--;
2090 }
2091 }
2092 Assert (flush != Z_NO_FLUSH, "no flush?")
2093 if (s->match_available) {
2094 Tracevv((stderr,"%c", s->window[s->st
2095 _tr_tally_lit(s, s->window[s->strstar
2096 s->match_available = 0;
2097 }
2098 s->insert = s->strstart < MIN_MATCH-1 ? s
2099 if (flush == Z_FINISH) {
2100 FLUSH_BLOCK(s, 1);
2101 return finish_done;
2102 }
2103 if (s->sym_next)
2104 FLUSH_BLOCK(s, 0);
2105 return block_done;
2106 }
2107 #endif /* FASTEST */
2108
2109 /* ==========================================
2110 * For Z_RLE, simply look for runs of bytes,
2111 * one. Do not maintain a hash table. (It w
2112 * deflate switches away from Z_RLE.)
2113 */
2114 local block_state deflate_rle(s, flush)
2115 deflate_state *s;
2116 int flush;
2117 {
2118 int bflush; /* set if current
2119 uInt prev; /* byte at distan
2120 Bytef *scan, *strend; /* scan goes up t
2121
2122 for (;;) {
2123 /* Make sure that we always have enou
2124 * at the end of the input file. We n
2125 * for the longest run, plus one for
2126 */
2127 if (s->lookahead <= MAX_MATCH) {
2128 fill_window(s);
2129 if (s->lookahead <= MAX_MATCH &&
2130 return need_more;
2131 }
2132 if (s->lookahead == 0) break; /*
2133 }
2134
2135 /* See how many times the previous by
2136 s->match_length = 0;
2137 if (s->lookahead >= MIN_MATCH && s->s
2138 scan = s->window + s->strstart -
2139 prev = *scan;
2140 if (prev == *++scan && prev == *+
2141 strend = s->window + s->strst
2142 do {
2143 } while (prev == *++scan && p
2144 prev == *++scan && p
2145 prev == *++scan && p
2146 prev == *++scan && p
2147 scan < strend);
2148 s->match_length = MAX_MATCH -
2149 if (s->match_length > s->look
2150 s->match_length = s->look
2151 }
2152 Assert(scan <= s->window + (uInt)
2153 "wild scan");
2154 }
2155
2156 /* Emit match if have run of MIN_MATC
2157 if (s->match_length >= MIN_MATCH) {
2158 check_match(s, s->strstart, s->st
2159
2160 _tr_tally_dist(s, 1, s->match_len
2161
2162 s->lookahead -= s->match_length;
2163 s->strstart += s->match_length;
2164 s->match_length = 0;
2165 } else {
2166 /* No match, output a literal byt
2167 Tracevv((stderr,"%c", s->window[s
2168 _tr_tally_lit(s, s->window[s->str
2169 s->lookahead--;
2170 s->strstart++;
2171 }
2172 if (bflush) FLUSH_BLOCK(s, 0);
2173 }
2174 s->insert = 0;
2175 if (flush == Z_FINISH) {
2176 FLUSH_BLOCK(s, 1);
2177 return finish_done;
2178 }
2179 if (s->sym_next)
2180 FLUSH_BLOCK(s, 0);
2181 return block_done;
2182 }
2183
2184 /* ==========================================
2185 * For Z_HUFFMAN_ONLY, do not look for matche
2186 * (It will be regenerated if this run of def
2187 */
2188 local block_state deflate_huff(s, flush)
2189 deflate_state *s;
2190 int flush;
2191 {
2192 int bflush; /* set if current
2193
2194 for (;;) {
2195 /* Make sure that we have a literal t
2196 if (s->lookahead == 0) {
2197 fill_window(s);
2198 if (s->lookahead == 0) {
2199 if (flush == Z_NO_FLUSH)
2200 return need_more;
2201 break; /* flush the curr
2202 }
2203 }
2204
2205 /* Output a literal byte */
2206 s->match_length = 0;
2207 Tracevv((stderr,"%c", s->window[s->st
2208 _tr_tally_lit(s, s->window[s->strstar
2209 s->lookahead--;
2210 s->strstart++;
2211 if (bflush) FLUSH_BLOCK(s, 0);
2212 }
2213 s->insert = 0;
2214 if (flush == Z_FINISH) {
2215 FLUSH_BLOCK(s, 1);
2216 return finish_done;
2217 }
2218 if (s->sym_next)
2219 FLUSH_BLOCK(s, 0);
2220 return block_done;
2221 }
2222