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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1 /* deflate.c -- compress data using the deflation algorithm
2 * Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6 /*
7 * ALGORITHM
8 *
9 * The "deflation" process depends on being able to identify portions
10 * of the input text which are identical to earlier input (within a
11 * sliding window trailing behind the input currently being processed).
12 *
13 * The most straightforward technique turns out to be the fastest for
14 * most input files: try all possible matches and select the longest.
15 * The key feature of this algorithm is that insertions into the string
16 * dictionary are very simple and thus fast, and deletions are avoided
17 * completely. Insertions are performed at each input character, whereas
18 * string matches are performed only when the previous match ends. So it
19 * is preferable to spend more time in matches to allow very fast string
20 * insertions and avoid deletions. The matching algorithm for small
21 * strings is inspired from that of Rabin & Karp. A brute force approach
22 * is used to find longer strings when a small match has been found.
23 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
24 * (by Leonid Broukhis).
25 * A previous version of this file used a more sophisticated algorithm
26 * (by Fiala and Greene) which is guaranteed to run in linear amortized
27 * time, but has a larger average cost, uses more memory and is patented.
28 * However the F&G algorithm may be faster for some highly redundant
29 * files if the parameter max_chain_length (described below) is too large.
30 *
31 * ACKNOWLEDGEMENTS
32 *
33 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
34 * I found it in 'freeze' written by Leonid Broukhis.
35 * Thanks to many people for bug reports and testing.
36 *
37 * REFERENCES
38 *
39 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
40 * Available in http://tools.ietf.org/html/rfc1951
41 *
42 * A description of the Rabin and Karp algorithm is given in the book
43 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
44 *
45 * Fiala,E.R., and Greene,D.H.
46 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
47 *
48 */
49
50 /* @(#) $Id$ */
51
52 #include "deflate.h"
53
54 const char deflate_copyright[] =
55 " deflate 1.3.1 Copyright 1995-2024 Jean-loup Gailly and Mark Adler ";
56 /*
57 If you use the zlib library in a product, an acknowledgment is welcome
58 in the documentation of your product. If for some reason you cannot
59 include such an acknowledgment, I would appreciate that you keep this
60 copyright string in the executable of your product.
61 */
62
63 typedef enum {
64 need_more, /* block not completed, need more input or more output */
65 block_done, /* block flush performed */
66 finish_started, /* finish started, need only more output at next deflate */
67 finish_done /* finish done, accept no more input or output */
68 } block_state;
69
70 typedef block_state (*compress_func)(deflate_state *s, int flush);
71 /* Compression function. Returns the block state after the call. */
72
73 local block_state deflate_stored(deflate_state *s, int flush);
74 local block_state deflate_fast(deflate_state *s, int flush);
75 #ifndef FASTEST
76 local block_state deflate_slow(deflate_state *s, int flush);
77 #endif
78 local block_state deflate_rle(deflate_state *s, int flush);
79 local block_state deflate_huff(deflate_state *s, int flush);
80
81 /* ===========================================================================
82 * Local data
83 */
84
85 #define NIL 0
86 /* Tail of hash chains */
87
88 #ifndef TOO_FAR
89 # define TOO_FAR 4096
90 #endif
91 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
92
93 /* Values for max_lazy_match, good_match and max_chain_length, depending on
94 * the desired pack level (0..9). The values given below have been tuned to
95 * exclude worst case performance for pathological files. Better values may be
96 * found for specific files.
97 */
98 typedef struct config_s {
99 ush good_length; /* reduce lazy search above this match length */
100 ush max_lazy; /* do not perform lazy search above this match length */
101 ush nice_length; /* quit search above this match length */
102 ush max_chain;
103 compress_func func;
104 } config;
105
106 #ifdef FASTEST
107 local const config configuration_table[2] = {
108 /* good lazy nice chain */
109 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
110 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
111 #else
112 local const config configuration_table[10] = {
113 /* good lazy nice chain */
114 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
115 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
116 /* 2 */ {4, 5, 16, 8, deflate_fast},
117 /* 3 */ {4, 6, 32, 32, deflate_fast},
118
119 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
120 /* 5 */ {8, 16, 32, 32, deflate_slow},
121 /* 6 */ {8, 16, 128, 128, deflate_slow},
122 /* 7 */ {8, 32, 128, 256, deflate_slow},
123 /* 8 */ {32, 128, 258, 1024, deflate_slow},
124 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
125 #endif
126
127 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
128 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
129 * meaning.
130 */
131
132 /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
133 #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
134
135 /* ===========================================================================
136 * Update a hash value with the given input byte
137 * IN assertion: all calls to UPDATE_HASH are made with consecutive input
138 * characters, so that a running hash key can be computed from the previous
139 * key instead of complete recalculation each time.
140 */
141 #define UPDATE_HASH(s,h,c) (h = (((h) << s->hash_shift) ^ (c)) & s->hash_mask)
142
143
144 /* ===========================================================================
145 * Insert string str in the dictionary and set match_head to the previous head
146 * of the hash chain (the most recent string with same hash key). Return
147 * the previous length of the hash chain.
148 * If this file is compiled with -DFASTEST, the compression level is forced
149 * to 1, and no hash chains are maintained.
150 * IN assertion: all calls to INSERT_STRING are made with consecutive input
151 * characters and the first MIN_MATCH bytes of str are valid (except for
152 * the last MIN_MATCH-1 bytes of the input file).
153 */
154 #ifdef FASTEST
155 #define INSERT_STRING(s, str, match_head) \
156 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
157 match_head = s->head[s->ins_h], \
158 s->head[s->ins_h] = (Pos)(str))
159 #else
160 #define INSERT_STRING(s, str, match_head) \
161 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
162 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
163 s->head[s->ins_h] = (Pos)(str))
164 #endif
165
166 /* ===========================================================================
167 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
168 * prev[] will be initialized on the fly.
169 */
170 #define CLEAR_HASH(s) \
171 do { \
172 s->head[s->hash_size - 1] = NIL; \
173 zmemzero((Bytef *)s->head, \
174 (unsigned)(s->hash_size - 1)*sizeof(*s->head)); \
175 } while (0)
176
177 /* ===========================================================================
178 * Slide the hash table when sliding the window down (could be avoided with 32
179 * bit values at the expense of memory usage). We slide even when level == 0 to
180 * keep the hash table consistent if we switch back to level > 0 later.
181 */
182 #if defined(__has_feature)
183 # if __has_feature(memory_sanitizer)
184 __attribute__((no_sanitize("memory")))
185 # endif
186 #endif
187 local void slide_hash(deflate_state *s) {
188 unsigned n, m;
189 Posf *p;
190 uInt wsize = s->w_size;
191
192 n = s->hash_size;
193 p = &s->head[n];
194 do {
195 m = *--p;
196 *p = (Pos)(m >= wsize ? m - wsize : NIL);
197 } while (--n);
198 n = wsize;
199 #ifndef FASTEST
200 p = &s->prev[n];
201 do {
202 m = *--p;
203 *p = (Pos)(m >= wsize ? m - wsize : NIL);
204 /* If n is not on any hash chain, prev[n] is garbage but
205 * its value will never be used.
206 */
207 } while (--n);
208 #endif
209 }
210
211 /* ===========================================================================
212 * Read a new buffer from the current input stream, update the adler32
213 * and total number of bytes read. All deflate() input goes through
214 * this function so some applications may wish to modify it to avoid
215 * allocating a large strm->next_in buffer and copying from it.
216 * (See also flush_pending()).
217 */
218 local unsigned read_buf(z_streamp strm, Bytef *buf, unsigned size) {
219 unsigned len = strm->avail_in;
220
221 if (len > size) len = size;
222 if (len == 0) return 0;
223
224 strm->avail_in -= len;
225
226 zmemcpy(buf, strm->next_in, len);
227 if (strm->state->wrap == 1) {
228 strm->adler = adler32(strm->adler, buf, len);
229 }
230 #ifdef GZIP
231 else if (strm->state->wrap == 2) {
232 strm->adler = crc32(strm->adler, buf, len);
233 }
234 #endif
235 strm->next_in += len;
236 strm->total_in += len;
237
238 return len;
239 }
240
241 /* ===========================================================================
242 * Fill the window when the lookahead becomes insufficient.
243 * Updates strstart and lookahead.
244 *
245 * IN assertion: lookahead < MIN_LOOKAHEAD
246 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
247 * At least one byte has been read, or avail_in == 0; reads are
248 * performed for at least two bytes (required for the zip translate_eol
249 * option -- not supported here).
250 */
251 local void fill_window(deflate_state *s) {
252 unsigned n;
253 unsigned more; /* Amount of free space at the end of the window. */
254 uInt wsize = s->w_size;
255
256 Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
257
258 do {
259 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
260
261 /* Deal with !@#$% 64K limit: */
262 if (sizeof(int) <= 2) {
263 if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
264 more = wsize;
265
266 } else if (more == (unsigned)(-1)) {
267 /* Very unlikely, but possible on 16 bit machine if
268 * strstart == 0 && lookahead == 1 (input done a byte at time)
269 */
270 more--;
271 }
272 }
273
274 /* If the window is almost full and there is insufficient lookahead,
275 * move the upper half to the lower one to make room in the upper half.
276 */
277 if (s->strstart >= wsize + MAX_DIST(s)) {
278
279 zmemcpy(s->window, s->window + wsize, (unsigned)wsize - more);
280 s->match_start -= wsize;
281 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
282 s->block_start -= (long) wsize;
283 if (s->insert > s->strstart)
284 s->insert = s->strstart;
285 slide_hash(s);
286 more += wsize;
287 }
288 if (s->strm->avail_in == 0) break;
289
290 /* If there was no sliding:
291 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
292 * more == window_size - lookahead - strstart
293 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
294 * => more >= window_size - 2*WSIZE + 2
295 * In the BIG_MEM or MMAP case (not yet supported),
296 * window_size == input_size + MIN_LOOKAHEAD &&
297 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
298 * Otherwise, window_size == 2*WSIZE so more >= 2.
299 * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
300 */
301 Assert(more >= 2, "more < 2");
302
303 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
304 s->lookahead += n;
305
306 /* Initialize the hash value now that we have some input: */
307 if (s->lookahead + s->insert >= MIN_MATCH) {
308 uInt str = s->strstart - s->insert;
309 s->ins_h = s->window[str];
310 UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
311 #if MIN_MATCH != 3
312 Call UPDATE_HASH() MIN_MATCH-3 more times
313 #endif
314 while (s->insert) {
315 UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
316 #ifndef FASTEST
317 s->prev[str & s->w_mask] = s->head[s->ins_h];
318 #endif
319 s->head[s->ins_h] = (Pos)str;
320 str++;
321 s->insert--;
322 if (s->lookahead + s->insert < MIN_MATCH)
323 break;
324 }
325 }
326 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
327 * but this is not important since only literal bytes will be emitted.
328 */
329
330 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
331
332 /* If the WIN_INIT bytes after the end of the current data have never been
333 * written, then zero those bytes in order to avoid memory check reports of
334 * the use of uninitialized (or uninitialised as Julian writes) bytes by
335 * the longest match routines. Update the high water mark for the next
336 * time through here. WIN_INIT is set to MAX_MATCH since the longest match
337 * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
338 */
339 if (s->high_water < s->window_size) {
340 ulg curr = s->strstart + (ulg)(s->lookahead);
341 ulg init;
342
343 if (s->high_water < curr) {
344 /* Previous high water mark below current data -- zero WIN_INIT
345 * bytes or up to end of window, whichever is less.
346 */
347 init = s->window_size - curr;
348 if (init > WIN_INIT)
349 init = WIN_INIT;
350 zmemzero(s->window + curr, (unsigned)init);
351 s->high_water = curr + init;
352 }
353 else if (s->high_water < (ulg)curr + WIN_INIT) {
354 /* High water mark at or above current data, but below current data
355 * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
356 * to end of window, whichever is less.
357 */
358 init = (ulg)curr + WIN_INIT - s->high_water;
359 if (init > s->window_size - s->high_water)
360 init = s->window_size - s->high_water;
361 zmemzero(s->window + s->high_water, (unsigned)init);
362 s->high_water += init;
363 }
364 }
365
366 Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
367 "not enough room for search");
368 }
369
370 /* ========================================================================= */
371 int ZEXPORT deflateInit_(z_streamp strm, int level, const char *version,
372 int stream_size) {
373 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
374 Z_DEFAULT_STRATEGY, version, stream_size);
375 /* To do: ignore strm->next_in if we use it as window */
376 }
377
378 /* ========================================================================= */
379 int ZEXPORT deflateInit2_(z_streamp strm, int level, int method,
380 int windowBits, int memLevel, int strategy,
381 const char *version, int stream_size) {
382 deflate_state *s;
383 int wrap = 1;
384 static const char my_version[] = ZLIB_VERSION;
385
386 if (version == Z_NULL || version[0] != my_version[0] ||
387 stream_size != sizeof(z_stream)) {
388 return Z_VERSION_ERROR;
389 }
390 if (strm == Z_NULL) return Z_STREAM_ERROR;
391
392 strm->msg = Z_NULL;
393 if (strm->zalloc == (alloc_func)0) {
394 #ifdef Z_SOLO
395 return Z_STREAM_ERROR;
396 #else
397 strm->zalloc = zcalloc;
398 strm->opaque = (voidpf)0;
399 #endif
400 }
401 if (strm->zfree == (free_func)0)
402 #ifdef Z_SOLO
403 return Z_STREAM_ERROR;
404 #else
405 strm->zfree = zcfree;
406 #endif
407
408 #ifdef FASTEST
409 if (level != 0) level = 1;
410 #else
411 if (level == Z_DEFAULT_COMPRESSION) level = 6;
412 #endif
413
414 if (windowBits < 0) { /* suppress zlib wrapper */
415 wrap = 0;
416 if (windowBits < -15)
417 return Z_STREAM_ERROR;
418 windowBits = -windowBits;
419 }
420 #ifdef GZIP
421 else if (windowBits > 15) {
422 wrap = 2; /* write gzip wrapper instead */
423 windowBits -= 16;
424 }
425 #endif
426 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
427 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
428 strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
429 return Z_STREAM_ERROR;
430 }
431 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
432 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
433 if (s == Z_NULL) return Z_MEM_ERROR;
434 strm->state = (struct internal_state FAR *)s;
435 s->strm = strm;
436 s->status = INIT_STATE; /* to pass state test in deflateReset() */
437
438 s->wrap = wrap;
439 s->gzhead = Z_NULL;
440 s->w_bits = (uInt)windowBits;
441 s->w_size = 1 << s->w_bits;
442 s->w_mask = s->w_size - 1;
443
444 s->hash_bits = (uInt)memLevel + 7;
445 s->hash_size = 1 << s->hash_bits;
446 s->hash_mask = s->hash_size - 1;
447 s->hash_shift = ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH);
448
449 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
450 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
451 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
452
453 s->high_water = 0; /* nothing written to s->window yet */
454
455 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
456
457 /* We overlay pending_buf and sym_buf. This works since the average size
458 * for length/distance pairs over any compressed block is assured to be 31
459 * bits or less.
460 *
461 * Analysis: The longest fixed codes are a length code of 8 bits plus 5
462 * extra bits, for lengths 131 to 257. The longest fixed distance codes are
463 * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
464 * possible fixed-codes length/distance pair is then 31 bits total.
465 *
466 * sym_buf starts one-fourth of the way into pending_buf. So there are
467 * three bytes in sym_buf for every four bytes in pending_buf. Each symbol
468 * in sym_buf is three bytes -- two for the distance and one for the
469 * literal/length. As each symbol is consumed, the pointer to the next
470 * sym_buf value to read moves forward three bytes. From that symbol, up to
471 * 31 bits are written to pending_buf. The closest the written pending_buf
472 * bits gets to the next sym_buf symbol to read is just before the last
473 * code is written. At that time, 31*(n - 2) bits have been written, just
474 * after 24*(n - 2) bits have been consumed from sym_buf. sym_buf starts at
475 * 8*n bits into pending_buf. (Note that the symbol buffer fills when n - 1
476 * symbols are written.) The closest the writing gets to what is unread is
477 * then n + 14 bits. Here n is lit_bufsize, which is 16384 by default, and
478 * can range from 128 to 32768.
479 *
480 * Therefore, at a minimum, there are 142 bits of space between what is
481 * written and what is read in the overlain buffers, so the symbols cannot
482 * be overwritten by the compressed data. That space is actually 139 bits,
483 * due to the three-bit fixed-code block header.
484 *
485 * That covers the case where either Z_FIXED is specified, forcing fixed
486 * codes, or when the use of fixed codes is chosen, because that choice
487 * results in a smaller compressed block than dynamic codes. That latter
488 * condition then assures that the above analysis also covers all dynamic
489 * blocks. A dynamic-code block will only be chosen to be emitted if it has
490 * fewer bits than a fixed-code block would for the same set of symbols.
491 * Therefore its average symbol length is assured to be less than 31. So
492 * the compressed data for a dynamic block also cannot overwrite the
493 * symbols from which it is being constructed.
494 */
495
496 s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, LIT_BUFS);
497 s->pending_buf_size = (ulg)s->lit_bufsize * 4;
498
499 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
500 s->pending_buf == Z_NULL) {
501 s->status = FINISH_STATE;
502 strm->msg = ERR_MSG(Z_MEM_ERROR);
503 deflateEnd (strm);
504 return Z_MEM_ERROR;
505 }
506 #ifdef LIT_MEM
507 s->d_buf = (ushf *)(s->pending_buf + (s->lit_bufsize << 1));
508 s->l_buf = s->pending_buf + (s->lit_bufsize << 2);
509 s->sym_end = s->lit_bufsize - 1;
510 #else
511 s->sym_buf = s->pending_buf + s->lit_bufsize;
512 s->sym_end = (s->lit_bufsize - 1) * 3;
513 #endif
514 /* We avoid equality with lit_bufsize*3 because of wraparound at 64K
515 * on 16 bit machines and because stored blocks are restricted to
516 * 64K-1 bytes.
517 */
518
519 s->level = level;
520 s->strategy = strategy;
521 s->method = (Byte)method;
522
523 return deflateReset(strm);
524 }
525
526 /* =========================================================================
527 * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
528 */
529 local int deflateStateCheck(z_streamp strm) {
530 deflate_state *s;
531 if (strm == Z_NULL ||
532 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
533 return 1;
534 s = strm->state;
535 if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
536 #ifdef GZIP
537 s->status != GZIP_STATE &&
538 #endif
539 s->status != EXTRA_STATE &&
540 s->status != NAME_STATE &&
541 s->status != COMMENT_STATE &&
542 s->status != HCRC_STATE &&
543 s->status != BUSY_STATE &&
544 s->status != FINISH_STATE))
545 return 1;
546 return 0;
547 }
548
549 /* ========================================================================= */
550 int ZEXPORT deflateSetDictionary(z_streamp strm, const Bytef *dictionary,
551 uInt dictLength) {
552 deflate_state *s;
553 uInt str, n;
554 int wrap;
555 unsigned avail;
556 z_const unsigned char *next;
557
558 if (deflateStateCheck(strm) || dictionary == Z_NULL)
559 return Z_STREAM_ERROR;
560 s = strm->state;
561 wrap = s->wrap;
562 if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
563 return Z_STREAM_ERROR;
564
565 /* when using zlib wrappers, compute Adler-32 for provided dictionary */
566 if (wrap == 1)
567 strm->adler = adler32(strm->adler, dictionary, dictLength);
568 s->wrap = 0; /* avoid computing Adler-32 in read_buf */
569
570 /* if dictionary would fill window, just replace the history */
571 if (dictLength >= s->w_size) {
572 if (wrap == 0) { /* already empty otherwise */
573 CLEAR_HASH(s);
574 s->strstart = 0;
575 s->block_start = 0L;
576 s->insert = 0;
577 }
578 dictionary += dictLength - s->w_size; /* use the tail */
579 dictLength = s->w_size;
580 }
581
582 /* insert dictionary into window and hash */
583 avail = strm->avail_in;
584 next = strm->next_in;
585 strm->avail_in = dictLength;
586 strm->next_in = (z_const Bytef *)dictionary;
587 fill_window(s);
588 while (s->lookahead >= MIN_MATCH) {
589 str = s->strstart;
590 n = s->lookahead - (MIN_MATCH-1);
591 do {
592 UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
593 #ifndef FASTEST
594 s->prev[str & s->w_mask] = s->head[s->ins_h];
595 #endif
596 s->head[s->ins_h] = (Pos)str;
597 str++;
598 } while (--n);
599 s->strstart = str;
600 s->lookahead = MIN_MATCH-1;
601 fill_window(s);
602 }
603 s->strstart += s->lookahead;
604 s->block_start = (long)s->strstart;
605 s->insert = s->lookahead;
606 s->lookahead = 0;
607 s->match_length = s->prev_length = MIN_MATCH-1;
608 s->match_available = 0;
609 strm->next_in = next;
610 strm->avail_in = avail;
611 s->wrap = wrap;
612 return Z_OK;
613 }
614
615 /* ========================================================================= */
616 int ZEXPORT deflateGetDictionary(z_streamp strm, Bytef *dictionary,
617 uInt *dictLength) {
618 deflate_state *s;
619 uInt len;
620
621 if (deflateStateCheck(strm))
622 return Z_STREAM_ERROR;
623 s = strm->state;
624 len = s->strstart + s->lookahead;
625 if (len > s->w_size)
626 len = s->w_size;
627 if (dictionary != Z_NULL && len)
628 zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
629 if (dictLength != Z_NULL)
630 *dictLength = len;
631 return Z_OK;
632 }
633
634 /* ========================================================================= */
635 int ZEXPORT deflateResetKeep(z_streamp strm) {
636 deflate_state *s;
637
638 if (deflateStateCheck(strm)) {
639 return Z_STREAM_ERROR;
640 }
641
642 strm->total_in = strm->total_out = 0;
643 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
644 strm->data_type = Z_UNKNOWN;
645
646 s = (deflate_state *)strm->state;
647 s->pending = 0;
648 s->pending_out = s->pending_buf;
649
650 if (s->wrap < 0) {
651 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
652 }
653 s->status =
654 #ifdef GZIP
655 s->wrap == 2 ? GZIP_STATE :
656 #endif
657 INIT_STATE;
658 strm->adler =
659 #ifdef GZIP
660 s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
661 #endif
662 adler32(0L, Z_NULL, 0);
663 s->last_flush = -2;
664
665 _tr_init(s);
666
667 return Z_OK;
668 }
669
670 /* ===========================================================================
671 * Initialize the "longest match" routines for a new zlib stream
672 */
673 local void lm_init(deflate_state *s) {
674 s->window_size = (ulg)2L*s->w_size;
675
676 CLEAR_HASH(s);
677
678 /* Set the default configuration parameters:
679 */
680 s->max_lazy_match = configuration_table[s->level].max_lazy;
681 s->good_match = configuration_table[s->level].good_length;
682 s->nice_match = configuration_table[s->level].nice_length;
683 s->max_chain_length = configuration_table[s->level].max_chain;
684
685 s->strstart = 0;
686 s->block_start = 0L;
687 s->lookahead = 0;
688 s->insert = 0;
689 s->match_length = s->prev_length = MIN_MATCH-1;
690 s->match_available = 0;
691 s->ins_h = 0;
692 }
693
694 /* ========================================================================= */
695 int ZEXPORT deflateReset(z_streamp strm) {
696 int ret;
697
698 ret = deflateResetKeep(strm);
699 if (ret == Z_OK)
700 lm_init(strm->state);
701 return ret;
702 }
703
704 /* ========================================================================= */
705 int ZEXPORT deflateSetHeader(z_streamp strm, gz_headerp head) {
706 if (deflateStateCheck(strm) || strm->state->wrap != 2)
707 return Z_STREAM_ERROR;
708 strm->state->gzhead = head;
709 return Z_OK;
710 }
711
712 /* ========================================================================= */
713 int ZEXPORT deflatePending(z_streamp strm, unsigned *pending, int *bits) {
714 if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
715 if (pending != Z_NULL)
716 *pending = strm->state->pending;
717 if (bits != Z_NULL)
718 *bits = strm->state->bi_valid;
719 return Z_OK;
720 }
721
722 /* ========================================================================= */
723 int ZEXPORT deflatePrime(z_streamp strm, int bits, int value) {
724 deflate_state *s;
725 int put;
726
727 if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
728 s = strm->state;
729 #ifdef LIT_MEM
730 if (bits < 0 || bits > 16 ||
731 (uchf *)s->d_buf < s->pending_out + ((Buf_size + 7) >> 3))
732 return Z_BUF_ERROR;
733 #else
734 if (bits < 0 || bits > 16 ||
735 s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
736 return Z_BUF_ERROR;
737 #endif
738 do {
739 put = Buf_size - s->bi_valid;
740 if (put > bits)
741 put = bits;
742 s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
743 s->bi_valid += put;
744 _tr_flush_bits(s);
745 value >>= put;
746 bits -= put;
747 } while (bits);
748 return Z_OK;
749 }
750
751 /* ========================================================================= */
752 int ZEXPORT deflateParams(z_streamp strm, int level, int strategy) {
753 deflate_state *s;
754 compress_func func;
755
756 if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
757 s = strm->state;
758
759 #ifdef FASTEST
760 if (level != 0) level = 1;
761 #else
762 if (level == Z_DEFAULT_COMPRESSION) level = 6;
763 #endif
764 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
765 return Z_STREAM_ERROR;
766 }
767 func = configuration_table[s->level].func;
768
769 if ((strategy != s->strategy || func != configuration_table[level].func) &&
770 s->last_flush != -2) {
771 /* Flush the last buffer: */
772 int err = deflate(strm, Z_BLOCK);
773 if (err == Z_STREAM_ERROR)
774 return err;
775 if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead)
776 return Z_BUF_ERROR;
777 }
778 if (s->level != level) {
779 if (s->level == 0 && s->matches != 0) {
780 if (s->matches == 1)
781 slide_hash(s);
782 else
783 CLEAR_HASH(s);
784 s->matches = 0;
785 }
786 s->level = level;
787 s->max_lazy_match = configuration_table[level].max_lazy;
788 s->good_match = configuration_table[level].good_length;
789 s->nice_match = configuration_table[level].nice_length;
790 s->max_chain_length = configuration_table[level].max_chain;
791 }
792 s->strategy = strategy;
793 return Z_OK;
794 }
795
796 /* ========================================================================= */
797 int ZEXPORT deflateTune(z_streamp strm, int good_length, int max_lazy,
798 int nice_length, int max_chain) {
799 deflate_state *s;
800
801 if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
802 s = strm->state;
803 s->good_match = (uInt)good_length;
804 s->max_lazy_match = (uInt)max_lazy;
805 s->nice_match = nice_length;
806 s->max_chain_length = (uInt)max_chain;
807 return Z_OK;
808 }
809
810 /* =========================================================================
811 * For the default windowBits of 15 and memLevel of 8, this function returns a
812 * close to exact, as well as small, upper bound on the compressed size. This
813 * is an expansion of ~0.03%, plus a small constant.
814 *
815 * For any setting other than those defaults for windowBits and memLevel, one
816 * of two worst case bounds is returned. This is at most an expansion of ~4% or
817 * ~13%, plus a small constant.
818 *
819 * Both the 0.03% and 4% derive from the overhead of stored blocks. The first
820 * one is for stored blocks of 16383 bytes (memLevel == 8), whereas the second
821 * is for stored blocks of 127 bytes (the worst case memLevel == 1). The
822 * expansion results from five bytes of header for each stored block.
823 *
824 * The larger expansion of 13% results from a window size less than or equal to
825 * the symbols buffer size (windowBits <= memLevel + 7). In that case some of
826 * the data being compressed may have slid out of the sliding window, impeding
827 * a stored block from being emitted. Then the only choice is a fixed or
828 * dynamic block, where a fixed block limits the maximum expansion to 9 bits
829 * per 8-bit byte, plus 10 bits for every block. The smallest block size for
830 * which this can occur is 255 (memLevel == 2).
831 *
832 * Shifts are used to approximate divisions, for speed.
833 */
834 uLong ZEXPORT deflateBound(z_streamp strm, uLong sourceLen) {
835 deflate_state *s;
836 uLong fixedlen, storelen, wraplen;
837
838 /* upper bound for fixed blocks with 9-bit literals and length 255
839 (memLevel == 2, which is the lowest that may not use stored blocks) --
840 ~13% overhead plus a small constant */
841 fixedlen = sourceLen + (sourceLen >> 3) + (sourceLen >> 8) +
842 (sourceLen >> 9) + 4;
843
844 /* upper bound for stored blocks with length 127 (memLevel == 1) --
845 ~4% overhead plus a small constant */
846 storelen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) +
847 (sourceLen >> 11) + 7;
848
849 /* if can't get parameters, return larger bound plus a zlib wrapper */
850 if (deflateStateCheck(strm))
851 return (fixedlen > storelen ? fixedlen : storelen) + 6;
852
853 /* compute wrapper length */
854 s = strm->state;
855 switch (s->wrap) {
856 case 0: /* raw deflate */
857 wraplen = 0;
858 break;
859 case 1: /* zlib wrapper */
860 wraplen = 6 + (s->strstart ? 4 : 0);
861 break;
862 #ifdef GZIP
863 case 2: /* gzip wrapper */
864 wraplen = 18;
865 if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
866 Bytef *str;
867 if (s->gzhead->extra != Z_NULL)
868 wraplen += 2 + s->gzhead->extra_len;
869 str = s->gzhead->name;
870 if (str != Z_NULL)
871 do {
872 wraplen++;
873 } while (*str++);
874 str = s->gzhead->comment;
875 if (str != Z_NULL)
876 do {
877 wraplen++;
878 } while (*str++);
879 if (s->gzhead->hcrc)
880 wraplen += 2;
881 }
882 break;
883 #endif
884 default: /* for compiler happiness */
885 wraplen = 6;
886 }
887
888 /* if not default parameters, return one of the conservative bounds */
889 if (s->w_bits != 15 || s->hash_bits != 8 + 7)
890 return (s->w_bits <= s->hash_bits && s->level ? fixedlen : storelen) +
891 wraplen;
892
893 /* default settings: return tight bound for that case -- ~0.03% overhead
894 plus a small constant */
895 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
896 (sourceLen >> 25) + 13 - 6 + wraplen;
897 }
898
899 /* =========================================================================
900 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
901 * IN assertion: the stream state is correct and there is enough room in
902 * pending_buf.
903 */
904 local void putShortMSB(deflate_state *s, uInt b) {
905 put_byte(s, (Byte)(b >> 8));
906 put_byte(s, (Byte)(b & 0xff));
907 }
908
909 /* =========================================================================
910 * Flush as much pending output as possible. All deflate() output, except for
911 * some deflate_stored() output, goes through this function so some
912 * applications may wish to modify it to avoid allocating a large
913 * strm->next_out buffer and copying into it. (See also read_buf()).
914 */
915 local void flush_pending(z_streamp strm) {
916 unsigned len;
917 deflate_state *s = strm->state;
918
919 _tr_flush_bits(s);
920 len = s->pending;
921 if (len > strm->avail_out) len = strm->avail_out;
922 if (len == 0) return;
923
924 zmemcpy(strm->next_out, s->pending_out, len);
925 strm->next_out += len;
926 s->pending_out += len;
927 strm->total_out += len;
928 strm->avail_out -= len;
929 s->pending -= len;
930 if (s->pending == 0) {
931 s->pending_out = s->pending_buf;
932 }
933 }
934
935 /* ===========================================================================
936 * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
937 */
938 #define HCRC_UPDATE(beg) \
939 do { \
940 if (s->gzhead->hcrc && s->pending > (beg)) \
941 strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
942 s->pending - (beg)); \
943 } while (0)
944
945 /* ========================================================================= */
946 int ZEXPORT deflate(z_streamp strm, int flush) {
947 int old_flush; /* value of flush param for previous deflate call */
948 deflate_state *s;
949
950 if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
951 return Z_STREAM_ERROR;
952 }
953 s = strm->state;
954
955 if (strm->next_out == Z_NULL ||
956 (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
957 (s->status == FINISH_STATE && flush != Z_FINISH)) {
958 ERR_RETURN(strm, Z_STREAM_ERROR);
959 }
960 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
961
962 old_flush = s->last_flush;
963 s->last_flush = flush;
964
965 /* Flush as much pending output as possible */
966 if (s->pending != 0) {
967 flush_pending(strm);
968 if (strm->avail_out == 0) {
969 /* Since avail_out is 0, deflate will be called again with
970 * more output space, but possibly with both pending and
971 * avail_in equal to zero. There won't be anything to do,
972 * but this is not an error situation so make sure we
973 * return OK instead of BUF_ERROR at next call of deflate:
974 */
975 s->last_flush = -1;
976 return Z_OK;
977 }
978
979 /* Make sure there is something to do and avoid duplicate consecutive
980 * flushes. For repeated and useless calls with Z_FINISH, we keep
981 * returning Z_STREAM_END instead of Z_BUF_ERROR.
982 */
983 } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
984 flush != Z_FINISH) {
985 ERR_RETURN(strm, Z_BUF_ERROR);
986 }
987
988 /* User must not provide more input after the first FINISH: */
989 if (s->status == FINISH_STATE && strm->avail_in != 0) {
990 ERR_RETURN(strm, Z_BUF_ERROR);
991 }
992
993 /* Write the header */
994 if (s->status == INIT_STATE && s->wrap == 0)
995 s->status = BUSY_STATE;
996 if (s->status == INIT_STATE) {
997 /* zlib header */
998 uInt header = (Z_DEFLATED + ((s->w_bits - 8) << 4)) << 8;
999 uInt level_flags;
1000
1001 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
1002 level_flags = 0;
1003 else if (s->level < 6)
1004 level_flags = 1;
1005 else if (s->level == 6)
1006 level_flags = 2;
1007 else
1008 level_flags = 3;
1009 header |= (level_flags << 6);
1010 if (s->strstart != 0) header |= PRESET_DICT;
1011 header += 31 - (header % 31);
1012
1013 putShortMSB(s, header);
1014
1015 /* Save the adler32 of the preset dictionary: */
1016 if (s->strstart != 0) {
1017 putShortMSB(s, (uInt)(strm->adler >> 16));
1018 putShortMSB(s, (uInt)(strm->adler & 0xffff));
1019 }
1020 strm->adler = adler32(0L, Z_NULL, 0);
1021 s->status = BUSY_STATE;
1022
1023 /* Compression must start with an empty pending buffer */
1024 flush_pending(strm);
1025 if (s->pending != 0) {
1026 s->last_flush = -1;
1027 return Z_OK;
1028 }
1029 }
1030 #ifdef GZIP
1031 if (s->status == GZIP_STATE) {
1032 /* gzip header */
1033 strm->adler = crc32(0L, Z_NULL, 0);
1034 put_byte(s, 31);
1035 put_byte(s, 139);
1036 put_byte(s, 8);
1037 if (s->gzhead == Z_NULL) {
1038 put_byte(s, 0);
1039 put_byte(s, 0);
1040 put_byte(s, 0);
1041 put_byte(s, 0);
1042 put_byte(s, 0);
1043 put_byte(s, s->level == 9 ? 2 :
1044 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
1045 4 : 0));
1046 put_byte(s, OS_CODE);
1047 s->status = BUSY_STATE;
1048
1049 /* Compression must start with an empty pending buffer */
1050 flush_pending(strm);
1051 if (s->pending != 0) {
1052 s->last_flush = -1;
1053 return Z_OK;
1054 }
1055 }
1056 else {
1057 put_byte(s, (s->gzhead->text ? 1 : 0) +
1058 (s->gzhead->hcrc ? 2 : 0) +
1059 (s->gzhead->extra == Z_NULL ? 0 : 4) +
1060 (s->gzhead->name == Z_NULL ? 0 : 8) +
1061 (s->gzhead->comment == Z_NULL ? 0 : 16)
1062 );
1063 put_byte(s, (Byte)(s->gzhead->time & 0xff));
1064 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
1065 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
1066 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
1067 put_byte(s, s->level == 9 ? 2 :
1068 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
1069 4 : 0));
1070 put_byte(s, s->gzhead->os & 0xff);
1071 if (s->gzhead->extra != Z_NULL) {
1072 put_byte(s, s->gzhead->extra_len & 0xff);
1073 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
1074 }
1075 if (s->gzhead->hcrc)
1076 strm->adler = crc32(strm->adler, s->pending_buf,
1077 s->pending);
1078 s->gzindex = 0;
1079 s->status = EXTRA_STATE;
1080 }
1081 }
1082 if (s->status == EXTRA_STATE) {
1083 if (s->gzhead->extra != Z_NULL) {
1084 ulg beg = s->pending; /* start of bytes to update crc */
1085 uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
1086 while (s->pending + left > s->pending_buf_size) {
1087 uInt copy = s->pending_buf_size - s->pending;
1088 zmemcpy(s->pending_buf + s->pending,
1089 s->gzhead->extra + s->gzindex, copy);
1090 s->pending = s->pending_buf_size;
1091 HCRC_UPDATE(beg);
1092 s->gzindex += copy;
1093 flush_pending(strm);
1094 if (s->pending != 0) {
1095 s->last_flush = -1;
1096 return Z_OK;
1097 }
1098 beg = 0;
1099 left -= copy;
1100 }
1101 zmemcpy(s->pending_buf + s->pending,
1102 s->gzhead->extra + s->gzindex, left);
1103 s->pending += left;
1104 HCRC_UPDATE(beg);
1105 s->gzindex = 0;
1106 }
1107 s->status = NAME_STATE;
1108 }
1109 if (s->status == NAME_STATE) {
1110 if (s->gzhead->name != Z_NULL) {
1111 ulg beg = s->pending; /* start of bytes to update crc */
1112 int val;
1113 do {
1114 if (s->pending == s->pending_buf_size) {
1115 HCRC_UPDATE(beg);
1116 flush_pending(strm);
1117 if (s->pending != 0) {
1118 s->last_flush = -1;
1119 return Z_OK;
1120 }
1121 beg = 0;
1122 }
1123 val = s->gzhead->name[s->gzindex++];
1124 put_byte(s, val);
1125 } while (val != 0);
1126 HCRC_UPDATE(beg);
1127 s->gzindex = 0;
1128 }
1129 s->status = COMMENT_STATE;
1130 }
1131 if (s->status == COMMENT_STATE) {
1132 if (s->gzhead->comment != Z_NULL) {
1133 ulg beg = s->pending; /* start of bytes to update crc */
1134 int val;
1135 do {
1136 if (s->pending == s->pending_buf_size) {
1137 HCRC_UPDATE(beg);
1138 flush_pending(strm);
1139 if (s->pending != 0) {
1140 s->last_flush = -1;
1141 return Z_OK;
1142 }
1143 beg = 0;
1144 }
1145 val = s->gzhead->comment[s->gzindex++];
1146 put_byte(s, val);
1147 } while (val != 0);
1148 HCRC_UPDATE(beg);
1149 }
1150 s->status = HCRC_STATE;
1151 }
1152 if (s->status == HCRC_STATE) {
1153 if (s->gzhead->hcrc) {
1154 if (s->pending + 2 > s->pending_buf_size) {
1155 flush_pending(strm);
1156 if (s->pending != 0) {
1157 s->last_flush = -1;
1158 return Z_OK;
1159 }
1160 }
1161 put_byte(s, (Byte)(strm->adler & 0xff));
1162 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
1163 strm->adler = crc32(0L, Z_NULL, 0);
1164 }
1165 s->status = BUSY_STATE;
1166
1167 /* Compression must start with an empty pending buffer */
1168 flush_pending(strm);
1169 if (s->pending != 0) {
1170 s->last_flush = -1;
1171 return Z_OK;
1172 }
1173 }
1174 #endif
1175
1176 /* Start a new block or continue the current one.
1177 */
1178 if (strm->avail_in != 0 || s->lookahead != 0 ||
1179 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
1180 block_state bstate;
1181
1182 bstate = s->level == 0 ? deflate_stored(s, flush) :
1183 s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
1184 s->strategy == Z_RLE ? deflate_rle(s, flush) :
1185 (*(configuration_table[s->level].func))(s, flush);
1186
1187 if (bstate == finish_started || bstate == finish_done) {
1188 s->status = FINISH_STATE;
1189 }
1190 if (bstate == need_more || bstate == finish_started) {
1191 if (strm->avail_out == 0) {
1192 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
1193 }
1194 return Z_OK;
1195 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
1196 * of deflate should use the same flush parameter to make sure
1197 * that the flush is complete. So we don't have to output an
1198 * empty block here, this will be done at next call. This also
1199 * ensures that for a very small output buffer, we emit at most
1200 * one empty block.
1201 */
1202 }
1203 if (bstate == block_done) {
1204 if (flush == Z_PARTIAL_FLUSH) {
1205 _tr_align(s);
1206 } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
1207 _tr_stored_block(s, (char*)0, 0L, 0);
1208 /* For a full flush, this empty block will be recognized
1209 * as a special marker by inflate_sync().
1210 */
1211 if (flush == Z_FULL_FLUSH) {
1212 CLEAR_HASH(s); /* forget history */
1213 if (s->lookahead == 0) {
1214 s->strstart = 0;
1215 s->block_start = 0L;
1216 s->insert = 0;
1217 }
1218 }
1219 }
1220 flush_pending(strm);
1221 if (strm->avail_out == 0) {
1222 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
1223 return Z_OK;
1224 }
1225 }
1226 }
1227
1228 if (flush != Z_FINISH) return Z_OK;
1229 if (s->wrap <= 0) return Z_STREAM_END;
1230
1231 /* Write the trailer */
1232 #ifdef GZIP
1233 if (s->wrap == 2) {
1234 put_byte(s, (Byte)(strm->adler & 0xff));
1235 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
1236 put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
1237 put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
1238 put_byte(s, (Byte)(strm->total_in & 0xff));
1239 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
1240 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
1241 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
1242 }
1243 else
1244 #endif
1245 {
1246 putShortMSB(s, (uInt)(strm->adler >> 16));
1247 putShortMSB(s, (uInt)(strm->adler & 0xffff));
1248 }
1249 flush_pending(strm);
1250 /* If avail_out is zero, the application will call deflate again
1251 * to flush the rest.
1252 */
1253 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
1254 return s->pending != 0 ? Z_OK : Z_STREAM_END;
1255 }
1256
1257 /* ========================================================================= */
1258 int ZEXPORT deflateEnd(z_streamp strm) {
1259 int status;
1260
1261 if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
1262
1263 status = strm->state->status;
1264
1265 /* Deallocate in reverse order of allocations: */
1266 TRY_FREE(strm, strm->state->pending_buf);
1267 TRY_FREE(strm, strm->state->head);
1268 TRY_FREE(strm, strm->state->prev);
1269 TRY_FREE(strm, strm->state->window);
1270
1271 ZFREE(strm, strm->state);
1272 strm->state = Z_NULL;
1273
1274 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
1275 }
1276
1277 /* =========================================================================
1278 * Copy the source state to the destination state.
1279 * To simplify the source, this is not supported for 16-bit MSDOS (which
1280 * doesn't have enough memory anyway to duplicate compression states).
1281 */
1282 int ZEXPORT deflateCopy(z_streamp dest, z_streamp source) {
1283 #ifdef MAXSEG_64K
1284 (void)dest;
1285 (void)source;
1286 return Z_STREAM_ERROR;
1287 #else
1288 deflate_state *ds;
1289 deflate_state *ss;
1290
1291
1292 if (deflateStateCheck(source) || dest == Z_NULL) {
1293 return Z_STREAM_ERROR;
1294 }
1295
1296 ss = source->state;
1297
1298 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
1299
1300 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
1301 if (ds == Z_NULL) return Z_MEM_ERROR;
1302 dest->state = (struct internal_state FAR *) ds;
1303 zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
1304 ds->strm = dest;
1305
1306 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
1307 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
1308 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
1309 ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, LIT_BUFS);
1310
1311 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
1312 ds->pending_buf == Z_NULL) {
1313 deflateEnd (dest);
1314 return Z_MEM_ERROR;
1315 }
1316 /* following zmemcpy do not work for 16-bit MSDOS */
1317 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
1318 zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
1319 zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
1320 zmemcpy(ds->pending_buf, ss->pending_buf, ds->lit_bufsize * LIT_BUFS);
1321
1322 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
1323 #ifdef LIT_MEM
1324 ds->d_buf = (ushf *)(ds->pending_buf + (ds->lit_bufsize << 1));
1325 ds->l_buf = ds->pending_buf + (ds->lit_bufsize << 2);
1326 #else
1327 ds->sym_buf = ds->pending_buf + ds->lit_bufsize;
1328 #endif
1329
1330 ds->l_desc.dyn_tree = ds->dyn_ltree;
1331 ds->d_desc.dyn_tree = ds->dyn_dtree;
1332 ds->bl_desc.dyn_tree = ds->bl_tree;
1333
1334 return Z_OK;
1335 #endif /* MAXSEG_64K */
1336 }
1337
1338 #ifndef FASTEST
1339 /* ===========================================================================
1340 * Set match_start to the longest match starting at the given string and
1341 * return its length. Matches shorter or equal to prev_length are discarded,
1342 * in which case the result is equal to prev_length and match_start is
1343 * garbage.
1344 * IN assertions: cur_match is the head of the hash chain for the current
1345 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1346 * OUT assertion: the match length is not greater than s->lookahead.
1347 */
1348 local uInt longest_match(deflate_state *s, IPos cur_match) {
1349 unsigned chain_length = s->max_chain_length;/* max hash chain length */
1350 register Bytef *scan = s->window + s->strstart; /* current string */
1351 register Bytef *match; /* matched string */
1352 register int len; /* length of current match */
1353 int best_len = (int)s->prev_length; /* best match length so far */
1354 int nice_match = s->nice_match; /* stop if match long enough */
1355 IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1356 s->strstart - (IPos)MAX_DIST(s) : NIL;
1357 /* Stop when cur_match becomes <= limit. To simplify the code,
1358 * we prevent matches with the string of window index 0.
1359 */
1360 Posf *prev = s->prev;
1361 uInt wmask = s->w_mask;
1362
1363 #ifdef UNALIGNED_OK
1364 /* Compare two bytes at a time. Note: this is not always beneficial.
1365 * Try with and without -DUNALIGNED_OK to check.
1366 */
1367 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1368 register ush scan_start = *(ushf*)scan;
1369 register ush scan_end = *(ushf*)(scan + best_len - 1);
1370 #else
1371 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1372 register Byte scan_end1 = scan[best_len - 1];
1373 register Byte scan_end = scan[best_len];
1374 #endif
1375
1376 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1377 * It is easy to get rid of this optimization if necessary.
1378 */
1379 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1380
1381 /* Do not waste too much time if we already have a good match: */
1382 if (s->prev_length >= s->good_match) {
1383 chain_length >>= 2;
1384 }
1385 /* Do not look for matches beyond the end of the input. This is necessary
1386 * to make deflate deterministic.
1387 */
1388 if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;
1389
1390 Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
1391 "need lookahead");
1392
1393 do {
1394 Assert(cur_match < s->strstart, "no future");
1395 match = s->window + cur_match;
1396
1397 /* Skip to next match if the match length cannot increase
1398 * or if the match length is less than 2. Note that the checks below
1399 * for insufficient lookahead only occur occasionally for performance
1400 * reasons. Therefore uninitialized memory will be accessed, and
1401 * conditional jumps will be made that depend on those values.
1402 * However the length of the match is limited to the lookahead, so
1403 * the output of deflate is not affected by the uninitialized values.
1404 */
1405 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1406 /* This code assumes sizeof(unsigned short) == 2. Do not use
1407 * UNALIGNED_OK if your compiler uses a different size.
1408 */
1409 if (*(ushf*)(match + best_len - 1) != scan_end ||
1410 *(ushf*)match != scan_start) continue;
1411
1412 /* It is not necessary to compare scan[2] and match[2] since they are
1413 * always equal when the other bytes match, given that the hash keys
1414 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1415 * strstart + 3, + 5, up to strstart + 257. We check for insufficient
1416 * lookahead only every 4th comparison; the 128th check will be made
1417 * at strstart + 257. If MAX_MATCH-2 is not a multiple of 8, it is
1418 * necessary to put more guard bytes at the end of the window, or
1419 * to check more often for insufficient lookahead.
1420 */
1421 Assert(scan[2] == match[2], "scan[2]?");
1422 scan++, match++;
1423 do {
1424 } while (*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
1425 *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
1426 *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
1427 *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
1428 scan < strend);
1429 /* The funny "do {}" generates better code on most compilers */
1430
1431 /* Here, scan <= window + strstart + 257 */
1432 Assert(scan <= s->window + (unsigned)(s->window_size - 1),
1433 "wild scan");
1434 if (*scan == *match) scan++;
1435
1436 len = (MAX_MATCH - 1) - (int)(strend - scan);
1437 scan = strend - (MAX_MATCH-1);
1438
1439 #else /* UNALIGNED_OK */
1440
1441 if (match[best_len] != scan_end ||
1442 match[best_len - 1] != scan_end1 ||
1443 *match != *scan ||
1444 *++match != scan[1]) continue;
1445
1446 /* The check at best_len - 1 can be removed because it will be made
1447 * again later. (This heuristic is not always a win.)
1448 * It is not necessary to compare scan[2] and match[2] since they
1449 * are always equal when the other bytes match, given that
1450 * the hash keys are equal and that HASH_BITS >= 8.
1451 */
1452 scan += 2, match++;
1453 Assert(*scan == *match, "match[2]?");
1454
1455 /* We check for insufficient lookahead only every 8th comparison;
1456 * the 256th check will be made at strstart + 258.
1457 */
1458 do {
1459 } while (*++scan == *++match && *++scan == *++match &&
1460 *++scan == *++match && *++scan == *++match &&
1461 *++scan == *++match && *++scan == *++match &&
1462 *++scan == *++match && *++scan == *++match &&
1463 scan < strend);
1464
1465 Assert(scan <= s->window + (unsigned)(s->window_size - 1),
1466 "wild scan");
1467
1468 len = MAX_MATCH - (int)(strend - scan);
1469 scan = strend - MAX_MATCH;
1470
1471 #endif /* UNALIGNED_OK */
1472
1473 if (len > best_len) {
1474 s->match_start = cur_match;
1475 best_len = len;
1476 if (len >= nice_match) break;
1477 #ifdef UNALIGNED_OK
1478 scan_end = *(ushf*)(scan + best_len - 1);
1479 #else
1480 scan_end1 = scan[best_len - 1];
1481 scan_end = scan[best_len];
1482 #endif
1483 }
1484 } while ((cur_match = prev[cur_match & wmask]) > limit
1485 && --chain_length != 0);
1486
1487 if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1488 return s->lookahead;
1489 }
1490
1491 #else /* FASTEST */
1492
1493 /* ---------------------------------------------------------------------------
1494 * Optimized version for FASTEST only
1495 */
1496 local uInt longest_match(deflate_state *s, IPos cur_match) {
1497 register Bytef *scan = s->window + s->strstart; /* current string */
1498 register Bytef *match; /* matched string */
1499 register int len; /* length of current match */
1500 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1501
1502 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1503 * It is easy to get rid of this optimization if necessary.
1504 */
1505 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1506
1507 Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
1508 "need lookahead");
1509
1510 Assert(cur_match < s->strstart, "no future");
1511
1512 match = s->window + cur_match;
1513
1514 /* Return failure if the match length is less than 2:
1515 */
1516 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1517
1518 /* The check at best_len - 1 can be removed because it will be made
1519 * again later. (This heuristic is not always a win.)
1520 * It is not necessary to compare scan[2] and match[2] since they
1521 * are always equal when the other bytes match, given that
1522 * the hash keys are equal and that HASH_BITS >= 8.
1523 */
1524 scan += 2, match += 2;
1525 Assert(*scan == *match, "match[2]?");
1526
1527 /* We check for insufficient lookahead only every 8th comparison;
1528 * the 256th check will be made at strstart + 258.
1529 */
1530 do {
1531 } while (*++scan == *++match && *++scan == *++match &&
1532 *++scan == *++match && *++scan == *++match &&
1533 *++scan == *++match && *++scan == *++match &&
1534 *++scan == *++match && *++scan == *++match &&
1535 scan < strend);
1536
1537 Assert(scan <= s->window + (unsigned)(s->window_size - 1), "wild scan");
1538
1539 len = MAX_MATCH - (int)(strend - scan);
1540
1541 if (len < MIN_MATCH) return MIN_MATCH - 1;
1542
1543 s->match_start = cur_match;
1544 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1545 }
1546
1547 #endif /* FASTEST */
1548
1549 #ifdef ZLIB_DEBUG
1550
1551 #define EQUAL 0
1552 /* result of memcmp for equal strings */
1553
1554 /* ===========================================================================
1555 * Check that the match at match_start is indeed a match.
1556 */
1557 local void check_match(deflate_state *s, IPos start, IPos match, int length) {
1558 /* check that the match is indeed a match */
1559 Bytef *back = s->window + (int)match, *here = s->window + start;
1560 IPos len = length;
1561 if (match == (IPos)-1) {
1562 /* match starts one byte before the current window -- just compare the
1563 subsequent length-1 bytes */
1564 back++;
1565 here++;
1566 len--;
1567 }
1568 if (zmemcmp(back, here, len) != EQUAL) {
1569 fprintf(stderr, " start %u, match %d, length %d\n",
1570 start, (int)match, length);
1571 do {
1572 fprintf(stderr, "(%02x %02x)", *back++, *here++);
1573 } while (--len != 0);
1574 z_error("invalid match");
1575 }
1576 if (z_verbose > 1) {
1577 fprintf(stderr,"\\[%d,%d]", start - match, length);
1578 do { putc(s->window[start++], stderr); } while (--length != 0);
1579 }
1580 }
1581 #else
1582 # define check_match(s, start, match, length)
1583 #endif /* ZLIB_DEBUG */
1584
1585 /* ===========================================================================
1586 * Flush the current block, with given end-of-file flag.
1587 * IN assertion: strstart is set to the end of the current match.
1588 */
1589 #define FLUSH_BLOCK_ONLY(s, last) { \
1590 _tr_flush_block(s, (s->block_start >= 0L ? \
1591 (charf *)&s->window[(unsigned)s->block_start] : \
1592 (charf *)Z_NULL), \
1593 (ulg)((long)s->strstart - s->block_start), \
1594 (last)); \
1595 s->block_start = s->strstart; \
1596 flush_pending(s->strm); \
1597 Tracev((stderr,"[FLUSH]")); \
1598 }
1599
1600 /* Same but force premature exit if necessary. */
1601 #define FLUSH_BLOCK(s, last) { \
1602 FLUSH_BLOCK_ONLY(s, last); \
1603 if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
1604 }
1605
1606 /* Maximum stored block length in deflate format (not including header). */
1607 #define MAX_STORED 65535
1608
1609 /* Minimum of a and b. */
1610 #define MIN(a, b) ((a) > (b) ? (b) : (a))
1611
1612 /* ===========================================================================
1613 * Copy without compression as much as possible from the input stream, return
1614 * the current block state.
1615 *
1616 * In case deflateParams() is used to later switch to a non-zero compression
1617 * level, s->matches (otherwise unused when storing) keeps track of the number
1618 * of hash table slides to perform. If s->matches is 1, then one hash table
1619 * slide will be done when switching. If s->matches is 2, the maximum value
1620 * allowed here, then the hash table will be cleared, since two or more slides
1621 * is the same as a clear.
1622 *
1623 * deflate_stored() is written to minimize the number of times an input byte is
1624 * copied. It is most efficient with large input and output buffers, which
1625 * maximizes the opportunities to have a single copy from next_in to next_out.
1626 */
1627 local block_state deflate_stored(deflate_state *s, int flush) {
1628 /* Smallest worthy block size when not flushing or finishing. By default
1629 * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
1630 * large input and output buffers, the stored block size will be larger.
1631 */
1632 unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);
1633
1634 /* Copy as many min_block or larger stored blocks directly to next_out as
1635 * possible. If flushing, copy the remaining available input to next_out as
1636 * stored blocks, if there is enough space.
1637 */
1638 unsigned len, left, have, last = 0;
1639 unsigned used = s->strm->avail_in;
1640 do {
1641 /* Set len to the maximum size block that we can copy directly with the
1642 * available input data and output space. Set left to how much of that
1643 * would be copied from what's left in the window.
1644 */
1645 len = MAX_STORED; /* maximum deflate stored block length */
1646 have = (s->bi_valid + 42) >> 3; /* number of header bytes */
1647 if (s->strm->avail_out < have) /* need room for header */
1648 break;
1649 /* maximum stored block length that will fit in avail_out: */
1650 have = s->strm->avail_out - have;
1651 left = s->strstart - s->block_start; /* bytes left in window */
1652 if (len > (ulg)left + s->strm->avail_in)
1653 len = left + s->strm->avail_in; /* limit len to the input */
1654 if (len > have)
1655 len = have; /* limit len to the output */
1656
1657 /* If the stored block would be less than min_block in length, or if
1658 * unable to copy all of the available input when flushing, then try
1659 * copying to the window and the pending buffer instead. Also don't
1660 * write an empty block when flushing -- deflate() does that.
1661 */
1662 if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
1663 flush == Z_NO_FLUSH ||
1664 len != left + s->strm->avail_in))
1665 break;
1666
1667 /* Make a dummy stored block in pending to get the header bytes,
1668 * including any pending bits. This also updates the debugging counts.
1669 */
1670 last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
1671 _tr_stored_block(s, (char *)0, 0L, last);
1672
1673 /* Replace the lengths in the dummy stored block with len. */
1674 s->pending_buf[s->pending - 4] = len;
1675 s->pending_buf[s->pending - 3] = len >> 8;
1676 s->pending_buf[s->pending - 2] = ~len;
1677 s->pending_buf[s->pending - 1] = ~len >> 8;
1678
1679 /* Write the stored block header bytes. */
1680 flush_pending(s->strm);
1681
1682 #ifdef ZLIB_DEBUG
1683 /* Update debugging counts for the data about to be copied. */
1684 s->compressed_len += len << 3;
1685 s->bits_sent += len << 3;
1686 #endif
1687
1688 /* Copy uncompressed bytes from the window to next_out. */
1689 if (left) {
1690 if (left > len)
1691 left = len;
1692 zmemcpy(s->strm->next_out, s->window + s->block_start, left);
1693 s->strm->next_out += left;
1694 s->strm->avail_out -= left;
1695 s->strm->total_out += left;
1696 s->block_start += left;
1697 len -= left;
1698 }
1699
1700 /* Copy uncompressed bytes directly from next_in to next_out, updating
1701 * the check value.
1702 */
1703 if (len) {
1704 read_buf(s->strm, s->strm->next_out, len);
1705 s->strm->next_out += len;
1706 s->strm->avail_out -= len;
1707 s->strm->total_out += len;
1708 }
1709 } while (last == 0);
1710
1711 /* Update the sliding window with the last s->w_size bytes of the copied
1712 * data, or append all of the copied data to the existing window if less
1713 * than s->w_size bytes were copied. Also update the number of bytes to
1714 * insert in the hash tables, in the event that deflateParams() switches to
1715 * a non-zero compression level.
1716 */
1717 used -= s->strm->avail_in; /* number of input bytes directly copied */
1718 if (used) {
1719 /* If any input was used, then no unused input remains in the window,
1720 * therefore s->block_start == s->strstart.
1721 */
1722 if (used >= s->w_size) { /* supplant the previous history */
1723 s->matches = 2; /* clear hash */
1724 zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
1725 s->strstart = s->w_size;
1726 s->insert = s->strstart;
1727 }
1728 else {
1729 if (s->window_size - s->strstart <= used) {
1730 /* Slide the window down. */
1731 s->strstart -= s->w_size;
1732 zmemcpy(s->window, s->window + s->w_size, s->strstart);
1733 if (s->matches < 2)
1734 s->matches++; /* add a pending slide_hash() */
1735 if (s->insert > s->strstart)
1736 s->insert = s->strstart;
1737 }
1738 zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
1739 s->strstart += used;
1740 s->insert += MIN(used, s->w_size - s->insert);
1741 }
1742 s->block_start = s->strstart;
1743 }
1744 if (s->high_water < s->strstart)
1745 s->high_water = s->strstart;
1746
1747 /* If the last block was written to next_out, then done. */
1748 if (last)
1749 return finish_done;
1750
1751 /* If flushing and all input has been consumed, then done. */
1752 if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
1753 s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
1754 return block_done;
1755
1756 /* Fill the window with any remaining input. */
1757 have = s->window_size - s->strstart;
1758 if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
1759 /* Slide the window down. */
1760 s->block_start -= s->w_size;
1761 s->strstart -= s->w_size;
1762 zmemcpy(s->window, s->window + s->w_size, s->strstart);
1763 if (s->matches < 2)
1764 s->matches++; /* add a pending slide_hash() */
1765 have += s->w_size; /* more space now */
1766 if (s->insert > s->strstart)
1767 s->insert = s->strstart;
1768 }
1769 if (have > s->strm->avail_in)
1770 have = s->strm->avail_in;
1771 if (have) {
1772 read_buf(s->strm, s->window + s->strstart, have);
1773 s->strstart += have;
1774 s->insert += MIN(have, s->w_size - s->insert);
1775 }
1776 if (s->high_water < s->strstart)
1777 s->high_water = s->strstart;
1778
1779 /* There was not enough avail_out to write a complete worthy or flushed
1780 * stored block to next_out. Write a stored block to pending instead, if we
1781 * have enough input for a worthy block, or if flushing and there is enough
1782 * room for the remaining input as a stored block in the pending buffer.
1783 */
1784 have = (s->bi_valid + 42) >> 3; /* number of header bytes */
1785 /* maximum stored block length that will fit in pending: */
1786 have = MIN(s->pending_buf_size - have, MAX_STORED);
1787 min_block = MIN(have, s->w_size);
1788 left = s->strstart - s->block_start;
1789 if (left >= min_block ||
1790 ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
1791 s->strm->avail_in == 0 && left <= have)) {
1792 len = MIN(left, have);
1793 last = flush == Z_FINISH && s->strm->avail_in == 0 &&
1794 len == left ? 1 : 0;
1795 _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
1796 s->block_start += len;
1797 flush_pending(s->strm);
1798 }
1799
1800 /* We've done all we can with the available input and output. */
1801 return last ? finish_started : need_more;
1802 }
1803
1804 /* ===========================================================================
1805 * Compress as much as possible from the input stream, return the current
1806 * block state.
1807 * This function does not perform lazy evaluation of matches and inserts
1808 * new strings in the dictionary only for unmatched strings or for short
1809 * matches. It is used only for the fast compression options.
1810 */
1811 local block_state deflate_fast(deflate_state *s, int flush) {
1812 IPos hash_head; /* head of the hash chain */
1813 int bflush; /* set if current block must be flushed */
1814
1815 for (;;) {
1816 /* Make sure that we always have enough lookahead, except
1817 * at the end of the input file. We need MAX_MATCH bytes
1818 * for the next match, plus MIN_MATCH bytes to insert the
1819 * string following the next match.
1820 */
1821 if (s->lookahead < MIN_LOOKAHEAD) {
1822 fill_window(s);
1823 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1824 return need_more;
1825 }
1826 if (s->lookahead == 0) break; /* flush the current block */
1827 }
1828
1829 /* Insert the string window[strstart .. strstart + 2] in the
1830 * dictionary, and set hash_head to the head of the hash chain:
1831 */
1832 hash_head = NIL;
1833 if (s->lookahead >= MIN_MATCH) {
1834 INSERT_STRING(s, s->strstart, hash_head);
1835 }
1836
1837 /* Find the longest match, discarding those <= prev_length.
1838 * At this point we have always match_length < MIN_MATCH
1839 */
1840 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1841 /* To simplify the code, we prevent matches with the string
1842 * of window index 0 (in particular we have to avoid a match
1843 * of the string with itself at the start of the input file).
1844 */
1845 s->match_length = longest_match (s, hash_head);
1846 /* longest_match() sets match_start */
1847 }
1848 if (s->match_length >= MIN_MATCH) {
1849 check_match(s, s->strstart, s->match_start, s->match_length);
1850
1851 _tr_tally_dist(s, s->strstart - s->match_start,
1852 s->match_length - MIN_MATCH, bflush);
1853
1854 s->lookahead -= s->match_length;
1855
1856 /* Insert new strings in the hash table only if the match length
1857 * is not too large. This saves time but degrades compression.
1858 */
1859 #ifndef FASTEST
1860 if (s->match_length <= s->max_insert_length &&
1861 s->lookahead >= MIN_MATCH) {
1862 s->match_length--; /* string at strstart already in table */
1863 do {
1864 s->strstart++;
1865 INSERT_STRING(s, s->strstart, hash_head);
1866 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1867 * always MIN_MATCH bytes ahead.
1868 */
1869 } while (--s->match_length != 0);
1870 s->strstart++;
1871 } else
1872 #endif
1873 {
1874 s->strstart += s->match_length;
1875 s->match_length = 0;
1876 s->ins_h = s->window[s->strstart];
1877 UPDATE_HASH(s, s->ins_h, s->window[s->strstart + 1]);
1878 #if MIN_MATCH != 3
1879 Call UPDATE_HASH() MIN_MATCH-3 more times
1880 #endif
1881 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1882 * matter since it will be recomputed at next deflate call.
1883 */
1884 }
1885 } else {
1886 /* No match, output a literal byte */
1887 Tracevv((stderr,"%c", s->window[s->strstart]));
1888 _tr_tally_lit(s, s->window[s->strstart], bflush);
1889 s->lookahead--;
1890 s->strstart++;
1891 }
1892 if (bflush) FLUSH_BLOCK(s, 0);
1893 }
1894 s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
1895 if (flush == Z_FINISH) {
1896 FLUSH_BLOCK(s, 1);
1897 return finish_done;
1898 }
1899 if (s->sym_next)
1900 FLUSH_BLOCK(s, 0);
1901 return block_done;
1902 }
1903
1904 #ifndef FASTEST
1905 /* ===========================================================================
1906 * Same as above, but achieves better compression. We use a lazy
1907 * evaluation for matches: a match is finally adopted only if there is
1908 * no better match at the next window position.
1909 */
1910 local block_state deflate_slow(deflate_state *s, int flush) {
1911 IPos hash_head; /* head of hash chain */
1912 int bflush; /* set if current block must be flushed */
1913
1914 /* Process the input block. */
1915 for (;;) {
1916 /* Make sure that we always have enough lookahead, except
1917 * at the end of the input file. We need MAX_MATCH bytes
1918 * for the next match, plus MIN_MATCH bytes to insert the
1919 * string following the next match.
1920 */
1921 if (s->lookahead < MIN_LOOKAHEAD) {
1922 fill_window(s);
1923 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1924 return need_more;
1925 }
1926 if (s->lookahead == 0) break; /* flush the current block */
1927 }
1928
1929 /* Insert the string window[strstart .. strstart + 2] in the
1930 * dictionary, and set hash_head to the head of the hash chain:
1931 */
1932 hash_head = NIL;
1933 if (s->lookahead >= MIN_MATCH) {
1934 INSERT_STRING(s, s->strstart, hash_head);
1935 }
1936
1937 /* Find the longest match, discarding those <= prev_length.
1938 */
1939 s->prev_length = s->match_length, s->prev_match = s->match_start;
1940 s->match_length = MIN_MATCH-1;
1941
1942 if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1943 s->strstart - hash_head <= MAX_DIST(s)) {
1944 /* To simplify the code, we prevent matches with the string
1945 * of window index 0 (in particular we have to avoid a match
1946 * of the string with itself at the start of the input file).
1947 */
1948 s->match_length = longest_match (s, hash_head);
1949 /* longest_match() sets match_start */
1950
1951 if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1952 #if TOO_FAR <= 32767
1953 || (s->match_length == MIN_MATCH &&
1954 s->strstart - s->match_start > TOO_FAR)
1955 #endif
1956 )) {
1957
1958 /* If prev_match is also MIN_MATCH, match_start is garbage
1959 * but we will ignore the current match anyway.
1960 */
1961 s->match_length = MIN_MATCH-1;
1962 }
1963 }
1964 /* If there was a match at the previous step and the current
1965 * match is not better, output the previous match:
1966 */
1967 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1968 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1969 /* Do not insert strings in hash table beyond this. */
1970
1971 check_match(s, s->strstart - 1, s->prev_match, s->prev_length);
1972
1973 _tr_tally_dist(s, s->strstart - 1 - s->prev_match,
1974 s->prev_length - MIN_MATCH, bflush);
1975
1976 /* Insert in hash table all strings up to the end of the match.
1977 * strstart - 1 and strstart are already inserted. If there is not
1978 * enough lookahead, the last two strings are not inserted in
1979 * the hash table.
1980 */
1981 s->lookahead -= s->prev_length - 1;
1982 s->prev_length -= 2;
1983 do {
1984 if (++s->strstart <= max_insert) {
1985 INSERT_STRING(s, s->strstart, hash_head);
1986 }
1987 } while (--s->prev_length != 0);
1988 s->match_available = 0;
1989 s->match_length = MIN_MATCH-1;
1990 s->strstart++;
1991
1992 if (bflush) FLUSH_BLOCK(s, 0);
1993
1994 } else if (s->match_available) {
1995 /* If there was no match at the previous position, output a
1996 * single literal. If there was a match but the current match
1997 * is longer, truncate the previous match to a single literal.
1998 */
1999 Tracevv((stderr,"%c", s->window[s->strstart - 1]));
2000 _tr_tally_lit(s, s->window[s->strstart - 1], bflush);
2001 if (bflush) {
2002 FLUSH_BLOCK_ONLY(s, 0);
2003 }
2004 s->strstart++;
2005 s->lookahead--;
2006 if (s->strm->avail_out == 0) return need_more;
2007 } else {
2008 /* There is no previous match to compare with, wait for
2009 * the next step to decide.
2010 */
2011 s->match_available = 1;
2012 s->strstart++;
2013 s->lookahead--;
2014 }
2015 }
2016 Assert (flush != Z_NO_FLUSH, "no flush?");
2017 if (s->match_available) {
2018 Tracevv((stderr,"%c", s->window[s->strstart - 1]));
2019 _tr_tally_lit(s, s->window[s->strstart - 1], bflush);
2020 s->match_available = 0;
2021 }
2022 s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
2023 if (flush == Z_FINISH) {
2024 FLUSH_BLOCK(s, 1);
2025 return finish_done;
2026 }
2027 if (s->sym_next)
2028 FLUSH_BLOCK(s, 0);
2029 return block_done;
2030 }
2031 #endif /* FASTEST */
2032
2033 /* ===========================================================================
2034 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
2035 * one. Do not maintain a hash table. (It will be regenerated if this run of
2036 * deflate switches away from Z_RLE.)
2037 */
2038 local block_state deflate_rle(deflate_state *s, int flush) {
2039 int bflush; /* set if current block must be flushed */
2040 uInt prev; /* byte at distance one to match */
2041 Bytef *scan, *strend; /* scan goes up to strend for length of run */
2042
2043 for (;;) {
2044 /* Make sure that we always have enough lookahead, except
2045 * at the end of the input file. We need MAX_MATCH bytes
2046 * for the longest run, plus one for the unrolled loop.
2047 */
2048 if (s->lookahead <= MAX_MATCH) {
2049 fill_window(s);
2050 if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
2051 return need_more;
2052 }
2053 if (s->lookahead == 0) break; /* flush the current block */
2054 }
2055
2056 /* See how many times the previous byte repeats */
2057 s->match_length = 0;
2058 if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
2059 scan = s->window + s->strstart - 1;
2060 prev = *scan;
2061 if (prev == *++scan && prev == *++scan && prev == *++scan) {
2062 strend = s->window + s->strstart + MAX_MATCH;
2063 do {
2064 } while (prev == *++scan && prev == *++scan &&
2065 prev == *++scan && prev == *++scan &&
2066 prev == *++scan && prev == *++scan &&
2067 prev == *++scan && prev == *++scan &&
2068 scan < strend);
2069 s->match_length = MAX_MATCH - (uInt)(strend - scan);
2070 if (s->match_length > s->lookahead)
2071 s->match_length = s->lookahead;
2072 }
2073 Assert(scan <= s->window + (uInt)(s->window_size - 1),
2074 "wild scan");
2075 }
2076
2077 /* Emit match if have run of MIN_MATCH or longer, else emit literal */
2078 if (s->match_length >= MIN_MATCH) {
2079 check_match(s, s->strstart, s->strstart - 1, s->match_length);
2080
2081 _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
2082
2083 s->lookahead -= s->match_length;
2084 s->strstart += s->match_length;
2085 s->match_length = 0;
2086 } else {
2087 /* No match, output a literal byte */
2088 Tracevv((stderr,"%c", s->window[s->strstart]));
2089 _tr_tally_lit(s, s->window[s->strstart], bflush);
2090 s->lookahead--;
2091 s->strstart++;
2092 }
2093 if (bflush) FLUSH_BLOCK(s, 0);
2094 }
2095 s->insert = 0;
2096 if (flush == Z_FINISH) {
2097 FLUSH_BLOCK(s, 1);
2098 return finish_done;
2099 }
2100 if (s->sym_next)
2101 FLUSH_BLOCK(s, 0);
2102 return block_done;
2103 }
2104
2105 /* ===========================================================================
2106 * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
2107 * (It will be regenerated if this run of deflate switches away from Huffman.)
2108 */
2109 local block_state deflate_huff(deflate_state *s, int flush) {
2110 int bflush; /* set if current block must be flushed */
2111
2112 for (;;) {
2113 /* Make sure that we have a literal to write. */
2114 if (s->lookahead == 0) {
2115 fill_window(s);
2116 if (s->lookahead == 0) {
2117 if (flush == Z_NO_FLUSH)
2118 return need_more;
2119 break; /* flush the current block */
2120 }
2121 }
2122
2123 /* Output a literal byte */
2124 s->match_length = 0;
2125 Tracevv((stderr,"%c", s->window[s->strstart]));
2126 _tr_tally_lit(s, s->window[s->strstart], bflush);
2127 s->lookahead--;
2128 s->strstart++;
2129 if (bflush) FLUSH_BLOCK(s, 0);
2130 }
2131 s->insert = 0;
2132 if (flush == Z_FINISH) {
2133 FLUSH_BLOCK(s, 1);
2134 return finish_done;
2135 }
2136 if (s->sym_next)
2137 FLUSH_BLOCK(s, 0);
2138 return block_done;
2139 }