1 : /* deflate.c -- compress data using the deflation algorithm
2 : * Copyright (C) 1995-2010 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://www.ietf.org/rfc/rfc1951.txt
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 1.2.5 Copyright 1995-2010 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 : /* ===========================================================================
64 : * Function prototypes.
65 : */
66 : typedef enum {
67 : need_more, /* block not completed, need more input or more output */
68 : block_done, /* block flush performed */
69 : finish_started, /* finish started, need only more output at next deflate */
70 : finish_done /* finish done, accept no more input or output */
71 : } block_state;
72 :
73 : typedef block_state (*compress_func) OF((deflate_state *s, int flush));
74 : /* Compression function. Returns the block state after the call. */
75 :
76 : local void fill_window OF((deflate_state *s));
77 : local block_state deflate_stored OF((deflate_state *s, int flush));
78 : local block_state deflate_fast OF((deflate_state *s, int flush));
79 : #ifndef FASTEST
80 : local block_state deflate_slow OF((deflate_state *s, int flush));
81 : #endif
82 : local block_state deflate_rle OF((deflate_state *s, int flush));
83 : local block_state deflate_huff OF((deflate_state *s, int flush));
84 : local void lm_init OF((deflate_state *s));
85 : local void putShortMSB OF((deflate_state *s, uInt b));
86 : local void flush_pending OF((z_streamp strm));
87 : local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
88 : #ifdef ASMV
89 : void match_init OF((void)); /* asm code initialization */
90 : uInt longest_match OF((deflate_state *s, IPos cur_match));
91 : #else
92 : local uInt longest_match OF((deflate_state *s, IPos cur_match));
93 : #endif
94 :
95 : #ifdef DEBUG
96 : local void check_match OF((deflate_state *s, IPos start, IPos match,
97 : int length));
98 : #endif
99 :
100 : /* ===========================================================================
101 : * Local data
102 : */
103 :
104 : #define NIL 0
105 : /* Tail of hash chains */
106 :
107 : #ifndef TOO_FAR
108 : # define TOO_FAR 4096
109 : #endif
110 : /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
111 :
112 : /* Values for max_lazy_match, good_match and max_chain_length, depending on
113 : * the desired pack level (0..9). The values given below have been tuned to
114 : * exclude worst case performance for pathological files. Better values may be
115 : * found for specific files.
116 : */
117 : typedef struct config_s {
118 : ush good_length; /* reduce lazy search above this match length */
119 : ush max_lazy; /* do not perform lazy search above this match length */
120 : ush nice_length; /* quit search above this match length */
121 : ush max_chain;
122 : compress_func func;
123 : } config;
124 :
125 : #ifdef FASTEST
126 : local const config configuration_table[2] = {
127 : /* good lazy nice chain */
128 : /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
129 : /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
130 : #else
131 : local const config configuration_table[10] = {
132 : /* good lazy nice chain */
133 : /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
134 : /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
135 : /* 2 */ {4, 5, 16, 8, deflate_fast},
136 : /* 3 */ {4, 6, 32, 32, deflate_fast},
137 :
138 : /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
139 : /* 5 */ {8, 16, 32, 32, deflate_slow},
140 : /* 6 */ {8, 16, 128, 128, deflate_slow},
141 : /* 7 */ {8, 32, 128, 256, deflate_slow},
142 : /* 8 */ {32, 128, 258, 1024, deflate_slow},
143 : /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
144 : #endif
145 :
146 : /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
147 : * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
148 : * meaning.
149 : */
150 :
151 : #define EQUAL 0
152 : /* result of memcmp for equal strings */
153 :
154 : #ifndef NO_DUMMY_DECL
155 : struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
156 : #endif
157 :
158 : /* ===========================================================================
159 : * Update a hash value with the given input byte
160 : * IN assertion: all calls to to UPDATE_HASH are made with consecutive
161 : * input characters, so that a running hash key can be computed from the
162 : * previous key instead of complete recalculation each time.
163 : */
164 : #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
165 :
166 :
167 : /* ===========================================================================
168 : * Insert string str in the dictionary and set match_head to the previous head
169 : * of the hash chain (the most recent string with same hash key). Return
170 : * the previous length of the hash chain.
171 : * If this file is compiled with -DFASTEST, the compression level is forced
172 : * to 1, and no hash chains are maintained.
173 : * IN assertion: all calls to to INSERT_STRING are made with consecutive
174 : * input characters and the first MIN_MATCH bytes of str are valid
175 : * (except for the last MIN_MATCH-1 bytes of the input file).
176 : */
177 : #ifdef FASTEST
178 : #define INSERT_STRING(s, str, match_head) \
179 : (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
180 : match_head = s->head[s->ins_h], \
181 : s->head[s->ins_h] = (Pos)(str))
182 : #else
183 : #define INSERT_STRING(s, str, match_head) \
184 : (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
185 : match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
186 : s->head[s->ins_h] = (Pos)(str))
187 : #endif
188 :
189 : /* ===========================================================================
190 : * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
191 : * prev[] will be initialized on the fly.
192 : */
193 : #define CLEAR_HASH(s) \
194 : s->head[s->hash_size-1] = NIL; \
195 : zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
196 :
197 : /* ========================================================================= */
198 0 : int ZEXPORT deflateInit_(strm, level, version, stream_size)
199 : z_streamp strm;
200 : int level;
201 : const char *version;
202 : int stream_size;
203 : {
204 0 : return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
205 : Z_DEFAULT_STRATEGY, version, stream_size);
206 : /* To do: ignore strm->next_in if we use it as window */
207 : }
208 :
209 : /* ========================================================================= */
210 5178 : int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
211 : version, stream_size)
212 : z_streamp strm;
213 : int level;
214 : int method;
215 : int windowBits;
216 : int memLevel;
217 : int strategy;
218 : const char *version;
219 : int stream_size;
220 : {
221 : deflate_state *s;
222 5178 : int wrap = 1;
223 : static const char my_version[] = ZLIB_VERSION;
224 :
225 : ushf *overlay;
226 : /* We overlay pending_buf and d_buf+l_buf. This works since the average
227 : * output size for (length,distance) codes is <= 24 bits.
228 : */
229 :
230 5178 : if (version == Z_NULL || version[0] != my_version[0] ||
231 : stream_size != sizeof(z_stream)) {
232 0 : return Z_VERSION_ERROR;
233 : }
234 5178 : if (strm == Z_NULL) return Z_STREAM_ERROR;
235 :
236 5178 : strm->msg = Z_NULL;
237 5178 : if (strm->zalloc == (alloc_func)0) {
238 5152 : strm->zalloc = zcalloc;
239 5152 : strm->opaque = (voidpf)0;
240 : }
241 5178 : if (strm->zfree == (free_func)0) strm->zfree = zcfree;
242 :
243 : #ifdef FASTEST
244 : if (level != 0) level = 1;
245 : #else
246 5178 : if (level == Z_DEFAULT_COMPRESSION) level = 6;
247 : #endif
248 :
249 5178 : if (windowBits < 0) { /* suppress zlib wrapper */
250 5146 : wrap = 0;
251 5146 : windowBits = -windowBits;
252 : }
253 : #ifdef GZIP
254 32 : else if (windowBits > 15) {
255 5 : wrap = 2; /* write gzip wrapper instead */
256 5 : windowBits -= 16;
257 : }
258 : #endif
259 5178 : if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
260 5178 : windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
261 5178 : strategy < 0 || strategy > Z_FIXED) {
262 0 : return Z_STREAM_ERROR;
263 : }
264 5178 : if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
265 5178 : s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
266 5178 : if (s == Z_NULL) return Z_MEM_ERROR;
267 5178 : strm->state = (struct internal_state FAR *)s;
268 5178 : s->strm = strm;
269 :
270 5178 : s->wrap = wrap;
271 5178 : s->gzhead = Z_NULL;
272 5178 : s->w_bits = windowBits;
273 5178 : s->w_size = 1 << s->w_bits;
274 5178 : s->w_mask = s->w_size - 1;
275 :
276 5178 : s->hash_bits = memLevel + 7;
277 5178 : s->hash_size = 1 << s->hash_bits;
278 5178 : s->hash_mask = s->hash_size - 1;
279 5178 : s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
280 :
281 5178 : s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
282 5178 : s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
283 5178 : s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
284 :
285 5178 : s->high_water = 0; /* nothing written to s->window yet */
286 :
287 5178 : s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
288 :
289 5178 : overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
290 5178 : s->pending_buf = (uchf *) overlay;
291 5178 : s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
292 :
293 10356 : if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
294 5178 : s->pending_buf == Z_NULL) {
295 0 : s->status = FINISH_STATE;
296 0 : strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
297 0 : deflateEnd (strm);
298 0 : return Z_MEM_ERROR;
299 : }
300 5178 : s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
301 5178 : s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
302 :
303 5178 : s->level = level;
304 5178 : s->strategy = strategy;
305 5178 : s->method = (Byte)method;
306 :
307 5178 : return deflateReset(strm);
308 : }
309 :
310 : /* ========================================================================= */
311 0 : int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
312 : z_streamp strm;
313 : const Bytef *dictionary;
314 : uInt dictLength;
315 : {
316 : deflate_state *s;
317 0 : uInt length = dictLength;
318 : uInt n;
319 0 : IPos hash_head = 0;
320 :
321 0 : if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
322 0 : strm->state->wrap == 2 ||
323 0 : (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
324 0 : return Z_STREAM_ERROR;
325 :
326 0 : s = strm->state;
327 0 : if (s->wrap)
328 0 : strm->adler = adler32(strm->adler, dictionary, dictLength);
329 :
330 0 : if (length < MIN_MATCH) return Z_OK;
331 0 : if (length > s->w_size) {
332 0 : length = s->w_size;
333 0 : dictionary += dictLength - length; /* use the tail of the dictionary */
334 : }
335 0 : zmemcpy(s->window, dictionary, length);
336 0 : s->strstart = length;
337 0 : s->block_start = (long)length;
338 :
339 : /* Insert all strings in the hash table (except for the last two bytes).
340 : * s->lookahead stays null, so s->ins_h will be recomputed at the next
341 : * call of fill_window.
342 : */
343 0 : s->ins_h = s->window[0];
344 0 : UPDATE_HASH(s, s->ins_h, s->window[1]);
345 0 : for (n = 0; n <= length - MIN_MATCH; n++) {
346 0 : INSERT_STRING(s, n, hash_head);
347 : }
348 0 : if (hash_head) hash_head = 0; /* to make compiler happy */
349 0 : return Z_OK;
350 : }
351 :
352 : /* ========================================================================= */
353 5217 : int ZEXPORT deflateReset (strm)
354 : z_streamp strm;
355 : {
356 : deflate_state *s;
357 :
358 10434 : if (strm == Z_NULL || strm->state == Z_NULL ||
359 10434 : strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
360 0 : return Z_STREAM_ERROR;
361 : }
362 :
363 5217 : strm->total_in = strm->total_out = 0;
364 5217 : strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
365 5217 : strm->data_type = Z_UNKNOWN;
366 :
367 5217 : s = (deflate_state *)strm->state;
368 5217 : s->pending = 0;
369 5217 : s->pending_out = s->pending_buf;
370 :
371 5217 : if (s->wrap < 0) {
372 39 : s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
373 : }
374 5217 : s->status = s->wrap ? INIT_STATE : BUSY_STATE;
375 5217 : strm->adler =
376 : #ifdef GZIP
377 5217 : s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
378 : #endif
379 : adler32(0L, Z_NULL, 0);
380 5217 : s->last_flush = Z_NO_FLUSH;
381 :
382 5217 : _tr_init(s);
383 5217 : lm_init(s);
384 :
385 5217 : return Z_OK;
386 : }
387 :
388 : /* ========================================================================= */
389 0 : int ZEXPORT deflateSetHeader (strm, head)
390 : z_streamp strm;
391 : gz_headerp head;
392 : {
393 0 : if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
394 0 : if (strm->state->wrap != 2) return Z_STREAM_ERROR;
395 0 : strm->state->gzhead = head;
396 0 : return Z_OK;
397 : }
398 :
399 : /* ========================================================================= */
400 0 : int ZEXPORT deflatePrime (strm, bits, value)
401 : z_streamp strm;
402 : int bits;
403 : int value;
404 : {
405 0 : if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
406 0 : strm->state->bi_valid = bits;
407 0 : strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
408 0 : return Z_OK;
409 : }
410 :
411 : /* ========================================================================= */
412 0 : int ZEXPORT deflateParams(strm, level, strategy)
413 : z_streamp strm;
414 : int level;
415 : int strategy;
416 : {
417 : deflate_state *s;
418 : compress_func func;
419 0 : int err = Z_OK;
420 :
421 0 : if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
422 0 : s = strm->state;
423 :
424 : #ifdef FASTEST
425 : if (level != 0) level = 1;
426 : #else
427 0 : if (level == Z_DEFAULT_COMPRESSION) level = 6;
428 : #endif
429 0 : if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
430 0 : return Z_STREAM_ERROR;
431 : }
432 0 : func = configuration_table[s->level].func;
433 :
434 0 : if ((strategy != s->strategy || func != configuration_table[level].func) &&
435 0 : strm->total_in != 0) {
436 : /* Flush the last buffer: */
437 0 : err = deflate(strm, Z_BLOCK);
438 : }
439 0 : if (s->level != level) {
440 0 : s->level = level;
441 0 : s->max_lazy_match = configuration_table[level].max_lazy;
442 0 : s->good_match = configuration_table[level].good_length;
443 0 : s->nice_match = configuration_table[level].nice_length;
444 0 : s->max_chain_length = configuration_table[level].max_chain;
445 : }
446 0 : s->strategy = strategy;
447 0 : return err;
448 : }
449 :
450 : /* ========================================================================= */
451 0 : int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
452 : z_streamp strm;
453 : int good_length;
454 : int max_lazy;
455 : int nice_length;
456 : int max_chain;
457 : {
458 : deflate_state *s;
459 :
460 0 : if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
461 0 : s = strm->state;
462 0 : s->good_match = good_length;
463 0 : s->max_lazy_match = max_lazy;
464 0 : s->nice_match = nice_length;
465 0 : s->max_chain_length = max_chain;
466 0 : return Z_OK;
467 : }
468 :
469 : /* =========================================================================
470 : * For the default windowBits of 15 and memLevel of 8, this function returns
471 : * a close to exact, as well as small, upper bound on the compressed size.
472 : * They are coded as constants here for a reason--if the #define's are
473 : * changed, then this function needs to be changed as well. The return
474 : * value for 15 and 8 only works for those exact settings.
475 : *
476 : * For any setting other than those defaults for windowBits and memLevel,
477 : * the value returned is a conservative worst case for the maximum expansion
478 : * resulting from using fixed blocks instead of stored blocks, which deflate
479 : * can emit on compressed data for some combinations of the parameters.
480 : *
481 : * This function could be more sophisticated to provide closer upper bounds for
482 : * every combination of windowBits and memLevel. But even the conservative
483 : * upper bound of about 14% expansion does not seem onerous for output buffer
484 : * allocation.
485 : */
486 0 : uLong ZEXPORT deflateBound(strm, sourceLen)
487 : z_streamp strm;
488 : uLong sourceLen;
489 : {
490 : deflate_state *s;
491 : uLong complen, wraplen;
492 : Bytef *str;
493 :
494 : /* conservative upper bound for compressed data */
495 0 : complen = sourceLen +
496 0 : ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
497 :
498 : /* if can't get parameters, return conservative bound plus zlib wrapper */
499 0 : if (strm == Z_NULL || strm->state == Z_NULL)
500 0 : return complen + 6;
501 :
502 : /* compute wrapper length */
503 0 : s = strm->state;
504 0 : switch (s->wrap) {
505 : case 0: /* raw deflate */
506 0 : wraplen = 0;
507 0 : break;
508 : case 1: /* zlib wrapper */
509 0 : wraplen = 6 + (s->strstart ? 4 : 0);
510 0 : break;
511 : case 2: /* gzip wrapper */
512 0 : wraplen = 18;
513 0 : if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
514 0 : if (s->gzhead->extra != Z_NULL)
515 0 : wraplen += 2 + s->gzhead->extra_len;
516 0 : str = s->gzhead->name;
517 0 : if (str != Z_NULL)
518 : do {
519 0 : wraplen++;
520 0 : } while (*str++);
521 0 : str = s->gzhead->comment;
522 0 : if (str != Z_NULL)
523 : do {
524 0 : wraplen++;
525 0 : } while (*str++);
526 0 : if (s->gzhead->hcrc)
527 0 : wraplen += 2;
528 : }
529 0 : break;
530 : default: /* for compiler happiness */
531 0 : wraplen = 6;
532 : }
533 :
534 : /* if not default parameters, return conservative bound */
535 0 : if (s->w_bits != 15 || s->hash_bits != 8 + 7)
536 0 : return complen + wraplen;
537 :
538 : /* default settings: return tight bound for that case */
539 0 : return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
540 0 : (sourceLen >> 25) + 13 - 6 + wraplen;
541 : }
542 :
543 : /* =========================================================================
544 : * Put a short in the pending buffer. The 16-bit value is put in MSB order.
545 : * IN assertion: the stream state is correct and there is enough room in
546 : * pending_buf.
547 : */
548 120 : local void putShortMSB (s, b)
549 : deflate_state *s;
550 : uInt b;
551 : {
552 120 : put_byte(s, (Byte)(b >> 8));
553 120 : put_byte(s, (Byte)(b & 0xff));
554 120 : }
555 :
556 : /* =========================================================================
557 : * Flush as much pending output as possible. All deflate() output goes
558 : * through this function so some applications may wish to modify it
559 : * to avoid allocating a large strm->next_out buffer and copying into it.
560 : * (See also read_buf()).
561 : */
562 35695 : local void flush_pending(strm)
563 : z_streamp strm;
564 : {
565 35695 : unsigned len = strm->state->pending;
566 :
567 35695 : if (len > strm->avail_out) len = strm->avail_out;
568 35695 : if (len == 0) return;
569 :
570 35695 : zmemcpy(strm->next_out, strm->state->pending_out, len);
571 35695 : strm->next_out += len;
572 35695 : strm->state->pending_out += len;
573 35695 : strm->total_out += len;
574 35695 : strm->avail_out -= len;
575 35695 : strm->state->pending -= len;
576 35695 : if (strm->state->pending == 0) {
577 7858 : strm->state->pending_out = strm->state->pending_buf;
578 : }
579 : }
580 :
581 : /* ========================================================================= */
582 195039 : int ZEXPORT deflate (strm, flush)
583 : z_streamp strm;
584 : int flush;
585 : {
586 : int old_flush; /* value of flush param for previous deflate call */
587 : deflate_state *s;
588 :
589 195039 : if (strm == Z_NULL || strm->state == Z_NULL ||
590 195039 : flush > Z_BLOCK || flush < 0) {
591 0 : return Z_STREAM_ERROR;
592 : }
593 195039 : s = strm->state;
594 :
595 390078 : if (strm->next_out == Z_NULL ||
596 390080 : (strm->next_in == Z_NULL && strm->avail_in != 0) ||
597 204897 : (s->status == FINISH_STATE && flush != Z_FINISH)) {
598 0 : ERR_RETURN(strm, Z_STREAM_ERROR);
599 : }
600 195039 : if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
601 :
602 195039 : s->strm = strm; /* just in case */
603 195039 : old_flush = s->last_flush;
604 195039 : s->last_flush = flush;
605 :
606 : /* Write the header */
607 195039 : if (s->status == INIT_STATE) {
608 : #ifdef GZIP
609 45 : if (s->wrap == 2) {
610 5 : strm->adler = crc32(0L, Z_NULL, 0);
611 5 : put_byte(s, 31);
612 5 : put_byte(s, 139);
613 5 : put_byte(s, 8);
614 5 : if (s->gzhead == Z_NULL) {
615 5 : put_byte(s, 0);
616 5 : put_byte(s, 0);
617 5 : put_byte(s, 0);
618 5 : put_byte(s, 0);
619 5 : put_byte(s, 0);
620 5 : put_byte(s, s->level == 9 ? 2 :
621 : (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
622 : 4 : 0));
623 5 : put_byte(s, OS_CODE);
624 5 : s->status = BUSY_STATE;
625 : }
626 : else {
627 0 : put_byte(s, (s->gzhead->text ? 1 : 0) +
628 : (s->gzhead->hcrc ? 2 : 0) +
629 : (s->gzhead->extra == Z_NULL ? 0 : 4) +
630 : (s->gzhead->name == Z_NULL ? 0 : 8) +
631 : (s->gzhead->comment == Z_NULL ? 0 : 16)
632 : );
633 0 : put_byte(s, (Byte)(s->gzhead->time & 0xff));
634 0 : put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
635 0 : put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
636 0 : put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
637 0 : put_byte(s, s->level == 9 ? 2 :
638 : (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
639 : 4 : 0));
640 0 : put_byte(s, s->gzhead->os & 0xff);
641 0 : if (s->gzhead->extra != Z_NULL) {
642 0 : put_byte(s, s->gzhead->extra_len & 0xff);
643 0 : put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
644 : }
645 0 : if (s->gzhead->hcrc)
646 0 : strm->adler = crc32(strm->adler, s->pending_buf,
647 : s->pending);
648 0 : s->gzindex = 0;
649 0 : s->status = EXTRA_STATE;
650 : }
651 : }
652 : else
653 : #endif
654 : {
655 40 : uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
656 : uInt level_flags;
657 :
658 40 : if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
659 0 : level_flags = 0;
660 40 : else if (s->level < 6)
661 0 : level_flags = 1;
662 40 : else if (s->level == 6)
663 40 : level_flags = 2;
664 : else
665 0 : level_flags = 3;
666 40 : header |= (level_flags << 6);
667 40 : if (s->strstart != 0) header |= PRESET_DICT;
668 40 : header += 31 - (header % 31);
669 :
670 40 : s->status = BUSY_STATE;
671 40 : putShortMSB(s, header);
672 :
673 : /* Save the adler32 of the preset dictionary: */
674 40 : if (s->strstart != 0) {
675 0 : putShortMSB(s, (uInt)(strm->adler >> 16));
676 0 : putShortMSB(s, (uInt)(strm->adler & 0xffff));
677 : }
678 40 : strm->adler = adler32(0L, Z_NULL, 0);
679 : }
680 : }
681 : #ifdef GZIP
682 195039 : if (s->status == EXTRA_STATE) {
683 0 : if (s->gzhead->extra != Z_NULL) {
684 0 : uInt beg = s->pending; /* start of bytes to update crc */
685 :
686 0 : while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
687 0 : if (s->pending == s->pending_buf_size) {
688 0 : if (s->gzhead->hcrc && s->pending > beg)
689 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
690 0 : s->pending - beg);
691 0 : flush_pending(strm);
692 0 : beg = s->pending;
693 0 : if (s->pending == s->pending_buf_size)
694 0 : break;
695 : }
696 0 : put_byte(s, s->gzhead->extra[s->gzindex]);
697 0 : s->gzindex++;
698 : }
699 0 : if (s->gzhead->hcrc && s->pending > beg)
700 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
701 0 : s->pending - beg);
702 0 : if (s->gzindex == s->gzhead->extra_len) {
703 0 : s->gzindex = 0;
704 0 : s->status = NAME_STATE;
705 : }
706 : }
707 : else
708 0 : s->status = NAME_STATE;
709 : }
710 195039 : if (s->status == NAME_STATE) {
711 0 : if (s->gzhead->name != Z_NULL) {
712 0 : uInt beg = s->pending; /* start of bytes to update crc */
713 : int val;
714 :
715 : do {
716 0 : if (s->pending == s->pending_buf_size) {
717 0 : if (s->gzhead->hcrc && s->pending > beg)
718 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
719 0 : s->pending - beg);
720 0 : flush_pending(strm);
721 0 : beg = s->pending;
722 0 : if (s->pending == s->pending_buf_size) {
723 0 : val = 1;
724 0 : break;
725 : }
726 : }
727 0 : val = s->gzhead->name[s->gzindex++];
728 0 : put_byte(s, val);
729 0 : } while (val != 0);
730 0 : if (s->gzhead->hcrc && s->pending > beg)
731 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
732 0 : s->pending - beg);
733 0 : if (val == 0) {
734 0 : s->gzindex = 0;
735 0 : s->status = COMMENT_STATE;
736 : }
737 : }
738 : else
739 0 : s->status = COMMENT_STATE;
740 : }
741 195039 : if (s->status == COMMENT_STATE) {
742 0 : if (s->gzhead->comment != Z_NULL) {
743 0 : uInt beg = s->pending; /* start of bytes to update crc */
744 : int val;
745 :
746 : do {
747 0 : if (s->pending == s->pending_buf_size) {
748 0 : if (s->gzhead->hcrc && s->pending > beg)
749 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
750 0 : s->pending - beg);
751 0 : flush_pending(strm);
752 0 : beg = s->pending;
753 0 : if (s->pending == s->pending_buf_size) {
754 0 : val = 1;
755 0 : break;
756 : }
757 : }
758 0 : val = s->gzhead->comment[s->gzindex++];
759 0 : put_byte(s, val);
760 0 : } while (val != 0);
761 0 : if (s->gzhead->hcrc && s->pending > beg)
762 0 : strm->adler = crc32(strm->adler, s->pending_buf + beg,
763 0 : s->pending - beg);
764 0 : if (val == 0)
765 0 : s->status = HCRC_STATE;
766 : }
767 : else
768 0 : s->status = HCRC_STATE;
769 : }
770 195039 : if (s->status == HCRC_STATE) {
771 0 : if (s->gzhead->hcrc) {
772 0 : if (s->pending + 2 > s->pending_buf_size)
773 0 : flush_pending(strm);
774 0 : if (s->pending + 2 <= s->pending_buf_size) {
775 0 : put_byte(s, (Byte)(strm->adler & 0xff));
776 0 : put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
777 0 : strm->adler = crc32(0L, Z_NULL, 0);
778 0 : s->status = BUSY_STATE;
779 : }
780 : }
781 : else
782 0 : s->status = BUSY_STATE;
783 : }
784 : #endif
785 :
786 : /* Flush as much pending output as possible */
787 195039 : if (s->pending != 0) {
788 27882 : flush_pending(strm);
789 27882 : if (strm->avail_out == 0) {
790 : /* Since avail_out is 0, deflate will be called again with
791 : * more output space, but possibly with both pending and
792 : * avail_in equal to zero. There won't be anything to do,
793 : * but this is not an error situation so make sure we
794 : * return OK instead of BUF_ERROR at next call of deflate:
795 : */
796 21795 : s->last_flush = -1;
797 21795 : return Z_OK;
798 : }
799 :
800 : /* Make sure there is something to do and avoid duplicate consecutive
801 : * flushes. For repeated and useless calls with Z_FINISH, we keep
802 : * returning Z_STREAM_END instead of Z_BUF_ERROR.
803 : */
804 167157 : } else if (strm->avail_in == 0 && flush <= old_flush &&
805 : flush != Z_FINISH) {
806 0 : ERR_RETURN(strm, Z_BUF_ERROR);
807 : }
808 :
809 : /* User must not provide more input after the first FINISH: */
810 173244 : if (s->status == FINISH_STATE && strm->avail_in != 0) {
811 0 : ERR_RETURN(strm, Z_BUF_ERROR);
812 : }
813 :
814 : /* Start a new block or continue the current one.
815 : */
816 173244 : if (strm->avail_in != 0 || s->lookahead != 0 ||
817 3468 : (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
818 : block_state bstate;
819 :
820 509334 : bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
821 169778 : (s->strategy == Z_RLE ? deflate_rle(s, flush) :
822 169778 : (*(configuration_table[s->level].func))(s, flush));
823 :
824 169778 : if (bstate == finish_started || bstate == finish_done) {
825 5191 : s->status = FINISH_STATE;
826 : }
827 169778 : if (bstate == need_more || bstate == finish_started) {
828 168053 : if (strm->avail_out == 0) {
829 6043 : s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
830 : }
831 168053 : return Z_OK;
832 : /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
833 : * of deflate should use the same flush parameter to make sure
834 : * that the flush is complete. So we don't have to output an
835 : * empty block here, this will be done at next call. This also
836 : * ensures that for a very small output buffer, we emit at most
837 : * one empty block.
838 : */
839 : }
840 1725 : if (bstate == block_done) {
841 0 : if (flush == Z_PARTIAL_FLUSH) {
842 0 : _tr_align(s);
843 0 : } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
844 0 : _tr_stored_block(s, (char*)0, 0L, 0);
845 : /* For a full flush, this empty block will be recognized
846 : * as a special marker by inflate_sync().
847 : */
848 0 : if (flush == Z_FULL_FLUSH) {
849 0 : CLEAR_HASH(s); /* forget history */
850 0 : if (s->lookahead == 0) {
851 0 : s->strstart = 0;
852 0 : s->block_start = 0L;
853 : }
854 : }
855 : }
856 0 : flush_pending(strm);
857 0 : if (strm->avail_out == 0) {
858 0 : s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
859 0 : return Z_OK;
860 : }
861 : }
862 : }
863 : Assert(strm->avail_out > 0, "bug2");
864 :
865 5191 : if (flush != Z_FINISH) return Z_OK;
866 5191 : if (s->wrap <= 0) return Z_STREAM_END;
867 :
868 : /* Write the trailer */
869 : #ifdef GZIP
870 45 : if (s->wrap == 2) {
871 5 : put_byte(s, (Byte)(strm->adler & 0xff));
872 5 : put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
873 5 : put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
874 5 : put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
875 5 : put_byte(s, (Byte)(strm->total_in & 0xff));
876 5 : put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
877 5 : put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
878 5 : put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
879 : }
880 : else
881 : #endif
882 : {
883 40 : putShortMSB(s, (uInt)(strm->adler >> 16));
884 40 : putShortMSB(s, (uInt)(strm->adler & 0xffff));
885 : }
886 45 : flush_pending(strm);
887 : /* If avail_out is zero, the application will call deflate again
888 : * to flush the rest.
889 : */
890 45 : if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
891 45 : return s->pending != 0 ? Z_OK : Z_STREAM_END;
892 : }
893 :
894 : /* ========================================================================= */
895 5178 : int ZEXPORT deflateEnd (strm)
896 : z_streamp strm;
897 : {
898 : int status;
899 :
900 5178 : if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
901 :
902 5178 : status = strm->state->status;
903 5178 : if (status != INIT_STATE &&
904 5152 : status != EXTRA_STATE &&
905 5152 : status != NAME_STATE &&
906 5152 : status != COMMENT_STATE &&
907 5152 : status != HCRC_STATE &&
908 5152 : status != BUSY_STATE &&
909 : status != FINISH_STATE) {
910 0 : return Z_STREAM_ERROR;
911 : }
912 :
913 : /* Deallocate in reverse order of allocations: */
914 5178 : TRY_FREE(strm, strm->state->pending_buf);
915 5178 : TRY_FREE(strm, strm->state->head);
916 5178 : TRY_FREE(strm, strm->state->prev);
917 5178 : TRY_FREE(strm, strm->state->window);
918 :
919 5178 : ZFREE(strm, strm->state);
920 5178 : strm->state = Z_NULL;
921 :
922 5178 : return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
923 : }
924 :
925 : /* =========================================================================
926 : * Copy the source state to the destination state.
927 : * To simplify the source, this is not supported for 16-bit MSDOS (which
928 : * doesn't have enough memory anyway to duplicate compression states).
929 : */
930 0 : int ZEXPORT deflateCopy (dest, source)
931 : z_streamp dest;
932 : z_streamp source;
933 : {
934 : #ifdef MAXSEG_64K
935 : return Z_STREAM_ERROR;
936 : #else
937 : deflate_state *ds;
938 : deflate_state *ss;
939 : ushf *overlay;
940 :
941 :
942 0 : if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
943 0 : return Z_STREAM_ERROR;
944 : }
945 :
946 0 : ss = source->state;
947 :
948 0 : zmemcpy(dest, source, sizeof(z_stream));
949 :
950 0 : ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
951 0 : if (ds == Z_NULL) return Z_MEM_ERROR;
952 0 : dest->state = (struct internal_state FAR *) ds;
953 0 : zmemcpy(ds, ss, sizeof(deflate_state));
954 0 : ds->strm = dest;
955 :
956 0 : ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
957 0 : ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
958 0 : ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
959 0 : overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
960 0 : ds->pending_buf = (uchf *) overlay;
961 :
962 0 : if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
963 0 : ds->pending_buf == Z_NULL) {
964 0 : deflateEnd (dest);
965 0 : return Z_MEM_ERROR;
966 : }
967 : /* following zmemcpy do not work for 16-bit MSDOS */
968 0 : zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
969 0 : zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
970 0 : zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
971 0 : zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
972 :
973 0 : ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
974 0 : ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
975 0 : ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
976 :
977 0 : ds->l_desc.dyn_tree = ds->dyn_ltree;
978 0 : ds->d_desc.dyn_tree = ds->dyn_dtree;
979 0 : ds->bl_desc.dyn_tree = ds->bl_tree;
980 :
981 0 : return Z_OK;
982 : #endif /* MAXSEG_64K */
983 : }
984 :
985 : /* ===========================================================================
986 : * Read a new buffer from the current input stream, update the adler32
987 : * and total number of bytes read. All deflate() input goes through
988 : * this function so some applications may wish to modify it to avoid
989 : * allocating a large strm->next_in buffer and copying from it.
990 : * (See also flush_pending()).
991 : */
992 162010 : local int read_buf(strm, buf, size)
993 : z_streamp strm;
994 : Bytef *buf;
995 : unsigned size;
996 : {
997 162010 : unsigned len = strm->avail_in;
998 :
999 162010 : if (len > size) len = size;
1000 162010 : if (len == 0) return 0;
1001 :
1002 162010 : strm->avail_in -= len;
1003 :
1004 162010 : if (strm->state->wrap == 1) {
1005 300 : strm->adler = adler32(strm->adler, strm->next_in, len);
1006 : }
1007 : #ifdef GZIP
1008 161710 : else if (strm->state->wrap == 2) {
1009 5 : strm->adler = crc32(strm->adler, strm->next_in, len);
1010 : }
1011 : #endif
1012 162010 : zmemcpy(buf, strm->next_in, len);
1013 162010 : strm->next_in += len;
1014 162010 : strm->total_in += len;
1015 :
1016 162010 : return (int)len;
1017 : }
1018 :
1019 : /* ===========================================================================
1020 : * Initialize the "longest match" routines for a new zlib stream
1021 : */
1022 5217 : local void lm_init (s)
1023 : deflate_state *s;
1024 : {
1025 5217 : s->window_size = (ulg)2L*s->w_size;
1026 :
1027 5217 : CLEAR_HASH(s);
1028 :
1029 : /* Set the default configuration parameters:
1030 : */
1031 5217 : s->max_lazy_match = configuration_table[s->level].max_lazy;
1032 5217 : s->good_match = configuration_table[s->level].good_length;
1033 5217 : s->nice_match = configuration_table[s->level].nice_length;
1034 5217 : s->max_chain_length = configuration_table[s->level].max_chain;
1035 :
1036 5217 : s->strstart = 0;
1037 5217 : s->block_start = 0L;
1038 5217 : s->lookahead = 0;
1039 5217 : s->match_length = s->prev_length = MIN_MATCH-1;
1040 5217 : s->match_available = 0;
1041 5217 : s->ins_h = 0;
1042 : #ifndef FASTEST
1043 : #ifdef ASMV
1044 : match_init(); /* initialize the asm code */
1045 : #endif
1046 : #endif
1047 5217 : }
1048 :
1049 : #ifndef FASTEST
1050 : /* ===========================================================================
1051 : * Set match_start to the longest match starting at the given string and
1052 : * return its length. Matches shorter or equal to prev_length are discarded,
1053 : * in which case the result is equal to prev_length and match_start is
1054 : * garbage.
1055 : * IN assertions: cur_match is the head of the hash chain for the current
1056 : * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1057 : * OUT assertion: the match length is not greater than s->lookahead.
1058 : */
1059 : #ifndef ASMV
1060 : /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
1061 : * match.S. The code will be functionally equivalent.
1062 : */
1063 57471294 : local uInt longest_match(s, cur_match)
1064 : deflate_state *s;
1065 : IPos cur_match; /* current match */
1066 : {
1067 57471294 : unsigned chain_length = s->max_chain_length;/* max hash chain length */
1068 57471294 : register Bytef *scan = s->window + s->strstart; /* current string */
1069 : register Bytef *match; /* matched string */
1070 : register int len; /* length of current match */
1071 57471294 : int best_len = s->prev_length; /* best match length so far */
1072 57471294 : int nice_match = s->nice_match; /* stop if match long enough */
1073 114942588 : IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1074 57471294 : s->strstart - (IPos)MAX_DIST(s) : NIL;
1075 : /* Stop when cur_match becomes <= limit. To simplify the code,
1076 : * we prevent matches with the string of window index 0.
1077 : */
1078 57471294 : Posf *prev = s->prev;
1079 57471294 : uInt wmask = s->w_mask;
1080 :
1081 : #ifdef UNALIGNED_OK
1082 : /* Compare two bytes at a time. Note: this is not always beneficial.
1083 : * Try with and without -DUNALIGNED_OK to check.
1084 : */
1085 : register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1086 : register ush scan_start = *(ushf*)scan;
1087 : register ush scan_end = *(ushf*)(scan+best_len-1);
1088 : #else
1089 57471294 : register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1090 57471294 : register Byte scan_end1 = scan[best_len-1];
1091 57471294 : register Byte scan_end = scan[best_len];
1092 : #endif
1093 :
1094 : /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1095 : * It is easy to get rid of this optimization if necessary.
1096 : */
1097 : Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1098 :
1099 : /* Do not waste too much time if we already have a good match: */
1100 57471294 : if (s->prev_length >= s->good_match) {
1101 654 : chain_length >>= 2;
1102 : }
1103 : /* Do not look for matches beyond the end of the input. This is necessary
1104 : * to make deflate deterministic.
1105 : */
1106 57471294 : if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1107 :
1108 : Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1109 :
1110 : do {
1111 : Assert(cur_match < s->strstart, "no future");
1112 159656033 : match = s->window + cur_match;
1113 :
1114 : /* Skip to next match if the match length cannot increase
1115 : * or if the match length is less than 2. Note that the checks below
1116 : * for insufficient lookahead only occur occasionally for performance
1117 : * reasons. Therefore uninitialized memory will be accessed, and
1118 : * conditional jumps will be made that depend on those values.
1119 : * However the length of the match is limited to the lookahead, so
1120 : * the output of deflate is not affected by the uninitialized values.
1121 : */
1122 : #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1123 : /* This code assumes sizeof(unsigned short) == 2. Do not use
1124 : * UNALIGNED_OK if your compiler uses a different size.
1125 : */
1126 : if (*(ushf*)(match+best_len-1) != scan_end ||
1127 : *(ushf*)match != scan_start) continue;
1128 :
1129 : /* It is not necessary to compare scan[2] and match[2] since they are
1130 : * always equal when the other bytes match, given that the hash keys
1131 : * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1132 : * strstart+3, +5, ... up to strstart+257. We check for insufficient
1133 : * lookahead only every 4th comparison; the 128th check will be made
1134 : * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1135 : * necessary to put more guard bytes at the end of the window, or
1136 : * to check more often for insufficient lookahead.
1137 : */
1138 : Assert(scan[2] == match[2], "scan[2]?");
1139 : scan++, match++;
1140 : do {
1141 : } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1142 : *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1143 : *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1144 : *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1145 : scan < strend);
1146 : /* The funny "do {}" generates better code on most compilers */
1147 :
1148 : /* Here, scan <= window+strstart+257 */
1149 : Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1150 : if (*scan == *match) scan++;
1151 :
1152 : len = (MAX_MATCH - 1) - (int)(strend-scan);
1153 : scan = strend - (MAX_MATCH-1);
1154 :
1155 : #else /* UNALIGNED_OK */
1156 :
1157 253558659 : if (match[best_len] != scan_end ||
1158 183849595 : match[best_len-1] != scan_end1 ||
1159 197393187 : *match != *scan ||
1160 159662829 : *++match != scan[1]) continue;
1161 :
1162 : /* The check at best_len-1 can be removed because it will be made
1163 : * again later. (This heuristic is not always a win.)
1164 : * It is not necessary to compare scan[2] and match[2] since they
1165 : * are always equal when the other bytes match, given that
1166 : * the hash keys are equal and that HASH_BITS >= 8.
1167 : */
1168 53716313 : scan += 2, match++;
1169 : Assert(*scan == *match, "match[2]?");
1170 :
1171 : /* We check for insufficient lookahead only every 8th comparison;
1172 : * the 256th check will be made at strstart+258.
1173 : */
1174 : do {
1175 431376401 : } while (*++scan == *++match && *++scan == *++match &&
1176 327597227 : *++scan == *++match && *++scan == *++match &&
1177 282333135 : *++scan == *++match && *++scan == *++match &&
1178 154648274 : *++scan == *++match && *++scan == *++match &&
1179 301913985 : scan < strend);
1180 :
1181 : Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1182 :
1183 53716313 : len = MAX_MATCH - (int)(strend - scan);
1184 53716313 : scan = strend - MAX_MATCH;
1185 :
1186 : #endif /* UNALIGNED_OK */
1187 :
1188 53716313 : if (len > best_len) {
1189 53475627 : s->match_start = cur_match;
1190 53475627 : best_len = len;
1191 53475627 : if (len >= nice_match) break;
1192 : #ifdef UNALIGNED_OK
1193 : scan_end = *(ushf*)(scan+best_len-1);
1194 : #else
1195 34266605 : scan_end1 = scan[best_len-1];
1196 34266605 : scan_end = scan[best_len];
1197 : #endif
1198 : }
1199 140447011 : } while ((cur_match = prev[cur_match & wmask]) > limit
1200 140447011 : && --chain_length != 0);
1201 :
1202 57471294 : if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1203 536 : return s->lookahead;
1204 : }
1205 : #endif /* ASMV */
1206 :
1207 : #else /* FASTEST */
1208 :
1209 : /* ---------------------------------------------------------------------------
1210 : * Optimized version for FASTEST only
1211 : */
1212 : local uInt longest_match(s, cur_match)
1213 : deflate_state *s;
1214 : IPos cur_match; /* current match */
1215 : {
1216 : register Bytef *scan = s->window + s->strstart; /* current string */
1217 : register Bytef *match; /* matched string */
1218 : register int len; /* length of current match */
1219 : register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1220 :
1221 : /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1222 : * It is easy to get rid of this optimization if necessary.
1223 : */
1224 : Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1225 :
1226 : Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1227 :
1228 : Assert(cur_match < s->strstart, "no future");
1229 :
1230 : match = s->window + cur_match;
1231 :
1232 : /* Return failure if the match length is less than 2:
1233 : */
1234 : if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1235 :
1236 : /* The check at best_len-1 can be removed because it will be made
1237 : * again later. (This heuristic is not always a win.)
1238 : * It is not necessary to compare scan[2] and match[2] since they
1239 : * are always equal when the other bytes match, given that
1240 : * the hash keys are equal and that HASH_BITS >= 8.
1241 : */
1242 : scan += 2, match += 2;
1243 : Assert(*scan == *match, "match[2]?");
1244 :
1245 : /* We check for insufficient lookahead only every 8th comparison;
1246 : * the 256th check will be made at strstart+258.
1247 : */
1248 : do {
1249 : } while (*++scan == *++match && *++scan == *++match &&
1250 : *++scan == *++match && *++scan == *++match &&
1251 : *++scan == *++match && *++scan == *++match &&
1252 : *++scan == *++match && *++scan == *++match &&
1253 : scan < strend);
1254 :
1255 : Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1256 :
1257 : len = MAX_MATCH - (int)(strend - scan);
1258 :
1259 : if (len < MIN_MATCH) return MIN_MATCH - 1;
1260 :
1261 : s->match_start = cur_match;
1262 : return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1263 : }
1264 :
1265 : #endif /* FASTEST */
1266 :
1267 : #ifdef DEBUG
1268 : /* ===========================================================================
1269 : * Check that the match at match_start is indeed a match.
1270 : */
1271 : local void check_match(s, start, match, length)
1272 : deflate_state *s;
1273 : IPos start, match;
1274 : int length;
1275 : {
1276 : /* check that the match is indeed a match */
1277 : if (zmemcmp(s->window + match,
1278 : s->window + start, length) != EQUAL) {
1279 : fprintf(stderr, " start %u, match %u, length %d\n",
1280 : start, match, length);
1281 : do {
1282 : fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
1283 : } while (--length != 0);
1284 : z_error("invalid match");
1285 : }
1286 : if (z_verbose > 1) {
1287 : fprintf(stderr,"\\[%d,%d]", start-match, length);
1288 : do { putc(s->window[start++], stderr); } while (--length != 0);
1289 : }
1290 : }
1291 : #else
1292 : # define check_match(s, start, match, length)
1293 : #endif /* DEBUG */
1294 :
1295 : /* ===========================================================================
1296 : * Fill the window when the lookahead becomes insufficient.
1297 : * Updates strstart and lookahead.
1298 : *
1299 : * IN assertion: lookahead < MIN_LOOKAHEAD
1300 : * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
1301 : * At least one byte has been read, or avail_in == 0; reads are
1302 : * performed for at least two bytes (required for the zip translate_eol
1303 : * option -- not supported here).
1304 : */
1305 543431 : local void fill_window(s)
1306 : deflate_state *s;
1307 : {
1308 : register unsigned n, m;
1309 : register Posf *p;
1310 : unsigned more; /* Amount of free space at the end of the window. */
1311 543431 : uInt wsize = s->w_size;
1312 :
1313 : do {
1314 543431 : more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
1315 :
1316 : /* Deal with !@#$% 64K limit: */
1317 : if (sizeof(int) <= 2) {
1318 : if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
1319 : more = wsize;
1320 :
1321 : } else if (more == (unsigned)(-1)) {
1322 : /* Very unlikely, but possible on 16 bit machine if
1323 : * strstart == 0 && lookahead == 1 (input done a byte at time)
1324 : */
1325 : more--;
1326 : }
1327 : }
1328 :
1329 : /* If the window is almost full and there is insufficient lookahead,
1330 : * move the upper half to the lower one to make room in the upper half.
1331 : */
1332 543431 : if (s->strstart >= wsize+MAX_DIST(s)) {
1333 :
1334 14331 : zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
1335 14331 : s->match_start -= wsize;
1336 14331 : s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
1337 14331 : s->block_start -= (long) wsize;
1338 :
1339 : /* Slide the hash table (could be avoided with 32 bit values
1340 : at the expense of memory usage). We slide even when level == 0
1341 : to keep the hash table consistent if we switch back to level > 0
1342 : later. (Using level 0 permanently is not an optimal usage of
1343 : zlib, so we don't care about this pathological case.)
1344 : */
1345 14331 : n = s->hash_size;
1346 14331 : p = &s->head[n];
1347 : do {
1348 469598208 : m = *--p;
1349 469598208 : *p = (Pos)(m >= wsize ? m-wsize : NIL);
1350 469598208 : } while (--n);
1351 :
1352 14331 : n = wsize;
1353 : #ifndef FASTEST
1354 14331 : p = &s->prev[n];
1355 : do {
1356 469598208 : m = *--p;
1357 469598208 : *p = (Pos)(m >= wsize ? m-wsize : NIL);
1358 : /* If n is not on any hash chain, prev[n] is garbage but
1359 : * its value will never be used.
1360 : */
1361 469598208 : } while (--n);
1362 : #endif
1363 14331 : more += wsize;
1364 : }
1365 543431 : if (s->strm->avail_in == 0) return;
1366 :
1367 : /* If there was no sliding:
1368 : * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
1369 : * more == window_size - lookahead - strstart
1370 : * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
1371 : * => more >= window_size - 2*WSIZE + 2
1372 : * In the BIG_MEM or MMAP case (not yet supported),
1373 : * window_size == input_size + MIN_LOOKAHEAD &&
1374 : * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
1375 : * Otherwise, window_size == 2*WSIZE so more >= 2.
1376 : * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
1377 : */
1378 : Assert(more >= 2, "more < 2");
1379 :
1380 162010 : n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
1381 162010 : s->lookahead += n;
1382 :
1383 : /* Initialize the hash value now that we have some input: */
1384 162010 : if (s->lookahead >= MIN_MATCH) {
1385 162010 : s->ins_h = s->window[s->strstart];
1386 162010 : UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1387 : #if MIN_MATCH != 3
1388 : Call UPDATE_HASH() MIN_MATCH-3 more times
1389 : #endif
1390 : }
1391 : /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
1392 : * but this is not important since only literal bytes will be emitted.
1393 : */
1394 :
1395 162010 : } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
1396 :
1397 : /* If the WIN_INIT bytes after the end of the current data have never been
1398 : * written, then zero those bytes in order to avoid memory check reports of
1399 : * the use of uninitialized (or uninitialised as Julian writes) bytes by
1400 : * the longest match routines. Update the high water mark for the next
1401 : * time through here. WIN_INIT is set to MAX_MATCH since the longest match
1402 : * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
1403 : */
1404 162010 : if (s->high_water < s->window_size) {
1405 55805 : ulg curr = s->strstart + (ulg)(s->lookahead);
1406 : ulg init;
1407 :
1408 55805 : if (s->high_water < curr) {
1409 : /* Previous high water mark below current data -- zero WIN_INIT
1410 : * bytes or up to end of window, whichever is less.
1411 : */
1412 55474 : init = s->window_size - curr;
1413 55474 : if (init > WIN_INIT)
1414 53029 : init = WIN_INIT;
1415 55474 : zmemzero(s->window + curr, (unsigned)init);
1416 55474 : s->high_water = curr + init;
1417 : }
1418 331 : else if (s->high_water < (ulg)curr + WIN_INIT) {
1419 : /* High water mark at or above current data, but below current data
1420 : * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
1421 : * to end of window, whichever is less.
1422 : */
1423 298 : init = (ulg)curr + WIN_INIT - s->high_water;
1424 298 : if (init > s->window_size - s->high_water)
1425 0 : init = s->window_size - s->high_water;
1426 298 : zmemzero(s->window + s->high_water, (unsigned)init);
1427 298 : s->high_water += init;
1428 : }
1429 : }
1430 : }
1431 :
1432 : /* ===========================================================================
1433 : * Flush the current block, with given end-of-file flag.
1434 : * IN assertion: strstart is set to the end of the current match.
1435 : */
1436 : #define FLUSH_BLOCK_ONLY(s, last) { \
1437 : _tr_flush_block(s, (s->block_start >= 0L ? \
1438 : (charf *)&s->window[(unsigned)s->block_start] : \
1439 : (charf *)Z_NULL), \
1440 : (ulg)((long)s->strstart - s->block_start), \
1441 : (last)); \
1442 : s->block_start = s->strstart; \
1443 : flush_pending(s->strm); \
1444 : Tracev((stderr,"[FLUSH]")); \
1445 : }
1446 :
1447 : /* Same but force premature exit if necessary. */
1448 : #define FLUSH_BLOCK(s, last) { \
1449 : FLUSH_BLOCK_ONLY(s, last); \
1450 : if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
1451 : }
1452 :
1453 : /* ===========================================================================
1454 : * Copy without compression as much as possible from the input stream, return
1455 : * the current block state.
1456 : * This function does not insert new strings in the dictionary since
1457 : * uncompressible data is probably not useful. This function is used
1458 : * only for the level=0 compression option.
1459 : * NOTE: this function should be optimized to avoid extra copying from
1460 : * window to pending_buf.
1461 : */
1462 0 : local block_state deflate_stored(s, flush)
1463 : deflate_state *s;
1464 : int flush;
1465 : {
1466 : /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
1467 : * to pending_buf_size, and each stored block has a 5 byte header:
1468 : */
1469 0 : ulg max_block_size = 0xffff;
1470 : ulg max_start;
1471 :
1472 0 : if (max_block_size > s->pending_buf_size - 5) {
1473 0 : max_block_size = s->pending_buf_size - 5;
1474 : }
1475 :
1476 : /* Copy as much as possible from input to output: */
1477 : for (;;) {
1478 : /* Fill the window as much as possible: */
1479 0 : if (s->lookahead <= 1) {
1480 :
1481 : Assert(s->strstart < s->w_size+MAX_DIST(s) ||
1482 : s->block_start >= (long)s->w_size, "slide too late");
1483 :
1484 0 : fill_window(s);
1485 0 : if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
1486 :
1487 0 : if (s->lookahead == 0) break; /* flush the current block */
1488 : }
1489 : Assert(s->block_start >= 0L, "block gone");
1490 :
1491 0 : s->strstart += s->lookahead;
1492 0 : s->lookahead = 0;
1493 :
1494 : /* Emit a stored block if pending_buf will be full: */
1495 0 : max_start = s->block_start + max_block_size;
1496 0 : if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
1497 : /* strstart == 0 is possible when wraparound on 16-bit machine */
1498 0 : s->lookahead = (uInt)(s->strstart - max_start);
1499 0 : s->strstart = (uInt)max_start;
1500 0 : FLUSH_BLOCK(s, 0);
1501 : }
1502 : /* Flush if we may have to slide, otherwise block_start may become
1503 : * negative and the data will be gone:
1504 : */
1505 0 : if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
1506 0 : FLUSH_BLOCK(s, 0);
1507 : }
1508 0 : }
1509 0 : FLUSH_BLOCK(s, flush == Z_FINISH);
1510 0 : return flush == Z_FINISH ? finish_done : block_done;
1511 : }
1512 :
1513 : /* ===========================================================================
1514 : * Compress as much as possible from the input stream, return the current
1515 : * block state.
1516 : * This function does not perform lazy evaluation of matches and inserts
1517 : * new strings in the dictionary only for unmatched strings or for short
1518 : * matches. It is used only for the fast compression options.
1519 : */
1520 69900590 : local block_state deflate_fast(s, flush)
1521 : deflate_state *s;
1522 : int flush;
1523 : {
1524 : IPos hash_head; /* head of the hash chain */
1525 : int bflush; /* set if current block must be flushed */
1526 :
1527 : for (;;) {
1528 : /* Make sure that we always have enough lookahead, except
1529 : * at the end of the input file. We need MAX_MATCH bytes
1530 : * for the next match, plus MIN_MATCH bytes to insert the
1531 : * string following the next match.
1532 : */
1533 69900590 : if (s->lookahead < MIN_LOOKAHEAD) {
1534 540536 : fill_window(s);
1535 540536 : if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1536 161702 : return need_more;
1537 : }
1538 378834 : if (s->lookahead == 0) break; /* flush the current block */
1539 : }
1540 :
1541 : /* Insert the string window[strstart .. strstart+2] in the
1542 : * dictionary, and set hash_head to the head of the hash chain:
1543 : */
1544 69733746 : hash_head = NIL;
1545 69733746 : if (s->lookahead >= MIN_MATCH) {
1546 69731857 : INSERT_STRING(s, s->strstart, hash_head);
1547 : }
1548 :
1549 : /* Find the longest match, discarding those <= prev_length.
1550 : * At this point we have always match_length < MIN_MATCH
1551 : */
1552 69733746 : if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1553 : /* To simplify the code, we prevent matches with the string
1554 : * of window index 0 (in particular we have to avoid a match
1555 : * of the string with itself at the start of the input file).
1556 : */
1557 57463510 : s->match_length = longest_match (s, hash_head);
1558 : /* longest_match() sets match_start */
1559 : }
1560 69733746 : if (s->match_length >= MIN_MATCH) {
1561 : check_match(s, s->strstart, s->match_start, s->match_length);
1562 :
1563 46897321 : _tr_tally_dist(s, s->strstart - s->match_start,
1564 : s->match_length - MIN_MATCH, bflush);
1565 :
1566 46897321 : s->lookahead -= s->match_length;
1567 :
1568 : /* Insert new strings in the hash table only if the match length
1569 : * is not too large. This saves time but degrades compression.
1570 : */
1571 : #ifndef FASTEST
1572 67721326 : if (s->match_length <= s->max_insert_length &&
1573 20824005 : s->lookahead >= MIN_MATCH) {
1574 20819810 : s->match_length--; /* string at strstart already in table */
1575 : do {
1576 54953209 : s->strstart++;
1577 54953209 : INSERT_STRING(s, s->strstart, hash_head);
1578 : /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1579 : * always MIN_MATCH bytes ahead.
1580 : */
1581 54953209 : } while (--s->match_length != 0);
1582 20819810 : s->strstart++;
1583 : } else
1584 : #endif
1585 : {
1586 26077511 : s->strstart += s->match_length;
1587 26077511 : s->match_length = 0;
1588 26077511 : s->ins_h = s->window[s->strstart];
1589 26077511 : UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1590 : #if MIN_MATCH != 3
1591 : Call UPDATE_HASH() MIN_MATCH-3 more times
1592 : #endif
1593 : /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1594 : * matter since it will be recomputed at next deflate call.
1595 : */
1596 : }
1597 : } else {
1598 : /* No match, output a literal byte */
1599 : Tracevv((stderr,"%c", s->window[s->strstart]));
1600 22836425 : _tr_tally_lit (s, s->window[s->strstart], bflush);
1601 22836425 : s->lookahead--;
1602 22836425 : s->strstart++;
1603 : }
1604 69733746 : if (bflush) FLUSH_BLOCK(s, 0);
1605 69731169 : }
1606 9001 : FLUSH_BLOCK(s, flush == Z_FINISH);
1607 1677 : return flush == Z_FINISH ? finish_done : block_done;
1608 : }
1609 :
1610 : #ifndef FASTEST
1611 : /* ===========================================================================
1612 : * Same as above, but achieves better compression. We use a lazy
1613 : * evaluation for matches: a match is finally adopted only if there is
1614 : * no better match at the next window position.
1615 : */
1616 25011 : local block_state deflate_slow(s, flush)
1617 : deflate_state *s;
1618 : int flush;
1619 : {
1620 : IPos hash_head; /* head of hash chain */
1621 : int bflush; /* set if current block must be flushed */
1622 :
1623 : /* Process the input block. */
1624 : for (;;) {
1625 : /* Make sure that we always have enough lookahead, except
1626 : * at the end of the input file. We need MAX_MATCH bytes
1627 : * for the next match, plus MIN_MATCH bytes to insert the
1628 : * string following the next match.
1629 : */
1630 25011 : if (s->lookahead < MIN_LOOKAHEAD) {
1631 2895 : fill_window(s);
1632 2895 : if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1633 308 : return need_more;
1634 : }
1635 2587 : if (s->lookahead == 0) break; /* flush the current block */
1636 : }
1637 :
1638 : /* Insert the string window[strstart .. strstart+2] in the
1639 : * dictionary, and set hash_head to the head of the hash chain:
1640 : */
1641 24654 : hash_head = NIL;
1642 24654 : if (s->lookahead >= MIN_MATCH) {
1643 24624 : INSERT_STRING(s, s->strstart, hash_head);
1644 : }
1645 :
1646 : /* Find the longest match, discarding those <= prev_length.
1647 : */
1648 24654 : s->prev_length = s->match_length, s->prev_match = s->match_start;
1649 24654 : s->match_length = MIN_MATCH-1;
1650 :
1651 32438 : if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1652 7784 : s->strstart - hash_head <= MAX_DIST(s)) {
1653 : /* To simplify the code, we prevent matches with the string
1654 : * of window index 0 (in particular we have to avoid a match
1655 : * of the string with itself at the start of the input file).
1656 : */
1657 7784 : s->match_length = longest_match (s, hash_head);
1658 : /* longest_match() sets match_start */
1659 :
1660 7784 : if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1661 : #if TOO_FAR <= 32767
1662 3566 : || (s->match_length == MIN_MATCH &&
1663 942 : s->strstart - s->match_start > TOO_FAR)
1664 : #endif
1665 : )) {
1666 :
1667 : /* If prev_match is also MIN_MATCH, match_start is garbage
1668 : * but we will ignore the current match anyway.
1669 : */
1670 2390 : s->match_length = MIN_MATCH-1;
1671 : }
1672 : }
1673 : /* If there was a match at the previous step and the current
1674 : * match is not better, output the previous match:
1675 : */
1676 27396 : if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1677 2742 : uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1678 : /* Do not insert strings in hash table beyond this. */
1679 :
1680 : check_match(s, s->strstart-1, s->prev_match, s->prev_length);
1681 :
1682 2742 : _tr_tally_dist(s, s->strstart -1 - s->prev_match,
1683 : s->prev_length - MIN_MATCH, bflush);
1684 :
1685 : /* Insert in hash table all strings up to the end of the match.
1686 : * strstart-1 and strstart are already inserted. If there is not
1687 : * enough lookahead, the last two strings are not inserted in
1688 : * the hash table.
1689 : */
1690 2742 : s->lookahead -= s->prev_length-1;
1691 2742 : s->prev_length -= 2;
1692 : do {
1693 36736 : if (++s->strstart <= max_insert) {
1694 36672 : INSERT_STRING(s, s->strstart, hash_head);
1695 : }
1696 36736 : } while (--s->prev_length != 0);
1697 2742 : s->match_available = 0;
1698 2742 : s->match_length = MIN_MATCH-1;
1699 2742 : s->strstart++;
1700 :
1701 2742 : if (bflush) FLUSH_BLOCK(s, 0);
1702 :
1703 21912 : } else if (s->match_available) {
1704 : /* If there was no match at the previous position, output a
1705 : * single literal. If there was a match but the current match
1706 : * is longer, truncate the previous match to a single literal.
1707 : */
1708 : Tracevv((stderr,"%c", s->window[s->strstart-1]));
1709 19155 : _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1710 19155 : if (bflush) {
1711 0 : FLUSH_BLOCK_ONLY(s, 0);
1712 : }
1713 19155 : s->strstart++;
1714 19155 : s->lookahead--;
1715 19155 : if (s->strm->avail_out == 0) return need_more;
1716 : } else {
1717 : /* There is no previous match to compare with, wait for
1718 : * the next step to decide.
1719 : */
1720 2757 : s->match_available = 1;
1721 2757 : s->strstart++;
1722 2757 : s->lookahead--;
1723 : }
1724 24654 : }
1725 : Assert (flush != Z_NO_FLUSH, "no flush?");
1726 49 : if (s->match_available) {
1727 : Tracevv((stderr,"%c", s->window[s->strstart-1]));
1728 15 : _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1729 15 : s->match_available = 0;
1730 : }
1731 49 : FLUSH_BLOCK(s, flush == Z_FINISH);
1732 48 : return flush == Z_FINISH ? finish_done : block_done;
1733 : }
1734 : #endif /* FASTEST */
1735 :
1736 : /* ===========================================================================
1737 : * For Z_RLE, simply look for runs of bytes, generate matches only of distance
1738 : * one. Do not maintain a hash table. (It will be regenerated if this run of
1739 : * deflate switches away from Z_RLE.)
1740 : */
1741 0 : local block_state deflate_rle(s, flush)
1742 : deflate_state *s;
1743 : int flush;
1744 : {
1745 : int bflush; /* set if current block must be flushed */
1746 : uInt prev; /* byte at distance one to match */
1747 : Bytef *scan, *strend; /* scan goes up to strend for length of run */
1748 :
1749 : for (;;) {
1750 : /* Make sure that we always have enough lookahead, except
1751 : * at the end of the input file. We need MAX_MATCH bytes
1752 : * for the longest encodable run.
1753 : */
1754 0 : if (s->lookahead < MAX_MATCH) {
1755 0 : fill_window(s);
1756 0 : if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
1757 0 : return need_more;
1758 : }
1759 0 : if (s->lookahead == 0) break; /* flush the current block */
1760 : }
1761 :
1762 : /* See how many times the previous byte repeats */
1763 0 : s->match_length = 0;
1764 0 : if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
1765 0 : scan = s->window + s->strstart - 1;
1766 0 : prev = *scan;
1767 0 : if (prev == *++scan && prev == *++scan && prev == *++scan) {
1768 0 : strend = s->window + s->strstart + MAX_MATCH;
1769 : do {
1770 0 : } while (prev == *++scan && prev == *++scan &&
1771 0 : prev == *++scan && prev == *++scan &&
1772 0 : prev == *++scan && prev == *++scan &&
1773 0 : prev == *++scan && prev == *++scan &&
1774 0 : scan < strend);
1775 0 : s->match_length = MAX_MATCH - (int)(strend - scan);
1776 0 : if (s->match_length > s->lookahead)
1777 0 : s->match_length = s->lookahead;
1778 : }
1779 : }
1780 :
1781 : /* Emit match if have run of MIN_MATCH or longer, else emit literal */
1782 0 : if (s->match_length >= MIN_MATCH) {
1783 : check_match(s, s->strstart, s->strstart - 1, s->match_length);
1784 :
1785 0 : _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
1786 :
1787 0 : s->lookahead -= s->match_length;
1788 0 : s->strstart += s->match_length;
1789 0 : s->match_length = 0;
1790 : } else {
1791 : /* No match, output a literal byte */
1792 : Tracevv((stderr,"%c", s->window[s->strstart]));
1793 0 : _tr_tally_lit (s, s->window[s->strstart], bflush);
1794 0 : s->lookahead--;
1795 0 : s->strstart++;
1796 : }
1797 0 : if (bflush) FLUSH_BLOCK(s, 0);
1798 0 : }
1799 0 : FLUSH_BLOCK(s, flush == Z_FINISH);
1800 0 : return flush == Z_FINISH ? finish_done : block_done;
1801 : }
1802 :
1803 : /* ===========================================================================
1804 : * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
1805 : * (It will be regenerated if this run of deflate switches away from Huffman.)
1806 : */
1807 0 : local block_state deflate_huff(s, flush)
1808 : deflate_state *s;
1809 : int flush;
1810 : {
1811 : int bflush; /* set if current block must be flushed */
1812 :
1813 : for (;;) {
1814 : /* Make sure that we have a literal to write. */
1815 0 : if (s->lookahead == 0) {
1816 0 : fill_window(s);
1817 0 : if (s->lookahead == 0) {
1818 0 : if (flush == Z_NO_FLUSH)
1819 0 : return need_more;
1820 : break; /* flush the current block */
1821 : }
1822 : }
1823 :
1824 : /* Output a literal byte */
1825 0 : s->match_length = 0;
1826 : Tracevv((stderr,"%c", s->window[s->strstart]));
1827 0 : _tr_tally_lit (s, s->window[s->strstart], bflush);
1828 0 : s->lookahead--;
1829 0 : s->strstart++;
1830 0 : if (bflush) FLUSH_BLOCK(s, 0);
1831 0 : }
1832 0 : FLUSH_BLOCK(s, flush == Z_FINISH);
1833 0 : return flush == Z_FINISH ? finish_done : block_done;
1834 : }
|