Mercurial > repos > blastem
comparison zlib/deflate.c @ 1530:00d788dac91a
Added support for reading gzipped ROMs
author | Michael Pavone <pavone@retrodev.com> |
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date | Fri, 23 Mar 2018 22:30:02 -0700 |
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1 /* deflate.c -- compress data using the deflation algorithm | |
2 * Copyright (C) 1995-2017 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 1.2.11 Copyright 1995-2017 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 int deflateStateCheck OF((z_streamp strm)); | |
77 local void slide_hash OF((deflate_state *s)); | |
78 local void fill_window OF((deflate_state *s)); | |
79 local block_state deflate_stored OF((deflate_state *s, int flush)); | |
80 local block_state deflate_fast OF((deflate_state *s, int flush)); | |
81 #ifndef FASTEST | |
82 local block_state deflate_slow OF((deflate_state *s, int flush)); | |
83 #endif | |
84 local block_state deflate_rle OF((deflate_state *s, int flush)); | |
85 local block_state deflate_huff OF((deflate_state *s, int flush)); | |
86 local void lm_init OF((deflate_state *s)); | |
87 local void putShortMSB OF((deflate_state *s, uInt b)); | |
88 local void flush_pending OF((z_streamp strm)); | |
89 local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); | |
90 #ifdef ASMV | |
91 # pragma message("Assembler code may have bugs -- use at your own risk") | |
92 void match_init OF((void)); /* asm code initialization */ | |
93 uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
94 #else | |
95 local uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
96 #endif | |
97 | |
98 #ifdef ZLIB_DEBUG | |
99 local void check_match OF((deflate_state *s, IPos start, IPos match, | |
100 int length)); | |
101 #endif | |
102 | |
103 /* =========================================================================== | |
104 * Local data | |
105 */ | |
106 | |
107 #define NIL 0 | |
108 /* Tail of hash chains */ | |
109 | |
110 #ifndef TOO_FAR | |
111 # define TOO_FAR 4096 | |
112 #endif | |
113 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ | |
114 | |
115 /* Values for max_lazy_match, good_match and max_chain_length, depending on | |
116 * the desired pack level (0..9). The values given below have been tuned to | |
117 * exclude worst case performance for pathological files. Better values may be | |
118 * found for specific files. | |
119 */ | |
120 typedef struct config_s { | |
121 ush good_length; /* reduce lazy search above this match length */ | |
122 ush max_lazy; /* do not perform lazy search above this match length */ | |
123 ush nice_length; /* quit search above this match length */ | |
124 ush max_chain; | |
125 compress_func func; | |
126 } config; | |
127 | |
128 #ifdef FASTEST | |
129 local const config configuration_table[2] = { | |
130 /* good lazy nice chain */ | |
131 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
132 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ | |
133 #else | |
134 local const config configuration_table[10] = { | |
135 /* good lazy nice chain */ | |
136 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
137 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ | |
138 /* 2 */ {4, 5, 16, 8, deflate_fast}, | |
139 /* 3 */ {4, 6, 32, 32, deflate_fast}, | |
140 | |
141 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ | |
142 /* 5 */ {8, 16, 32, 32, deflate_slow}, | |
143 /* 6 */ {8, 16, 128, 128, deflate_slow}, | |
144 /* 7 */ {8, 32, 128, 256, deflate_slow}, | |
145 /* 8 */ {32, 128, 258, 1024, deflate_slow}, | |
146 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ | |
147 #endif | |
148 | |
149 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 | |
150 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different | |
151 * meaning. | |
152 */ | |
153 | |
154 /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */ | |
155 #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0)) | |
156 | |
157 /* =========================================================================== | |
158 * Update a hash value with the given input byte | |
159 * IN assertion: all calls to UPDATE_HASH are made with consecutive input | |
160 * characters, so that a running hash key can be computed from the previous | |
161 * key instead of complete recalculation each time. | |
162 */ | |
163 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) | |
164 | |
165 | |
166 /* =========================================================================== | |
167 * Insert string str in the dictionary and set match_head to the previous head | |
168 * of the hash chain (the most recent string with same hash key). Return | |
169 * the previous length of the hash chain. | |
170 * If this file is compiled with -DFASTEST, the compression level is forced | |
171 * to 1, and no hash chains are maintained. | |
172 * IN assertion: all calls to INSERT_STRING are made with consecutive input | |
173 * characters and the first MIN_MATCH bytes of str are valid (except for | |
174 * the last MIN_MATCH-1 bytes of the input file). | |
175 */ | |
176 #ifdef FASTEST | |
177 #define INSERT_STRING(s, str, match_head) \ | |
178 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
179 match_head = s->head[s->ins_h], \ | |
180 s->head[s->ins_h] = (Pos)(str)) | |
181 #else | |
182 #define INSERT_STRING(s, str, match_head) \ | |
183 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
184 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ | |
185 s->head[s->ins_h] = (Pos)(str)) | |
186 #endif | |
187 | |
188 /* =========================================================================== | |
189 * Initialize the hash table (avoiding 64K overflow for 16 bit systems). | |
190 * prev[] will be initialized on the fly. | |
191 */ | |
192 #define CLEAR_HASH(s) \ | |
193 s->head[s->hash_size-1] = NIL; \ | |
194 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); | |
195 | |
196 /* =========================================================================== | |
197 * Slide the hash table when sliding the window down (could be avoided with 32 | |
198 * bit values at the expense of memory usage). We slide even when level == 0 to | |
199 * keep the hash table consistent if we switch back to level > 0 later. | |
200 */ | |
201 local void slide_hash(s) | |
202 deflate_state *s; | |
203 { | |
204 unsigned n, m; | |
205 Posf *p; | |
206 uInt wsize = s->w_size; | |
207 | |
208 n = s->hash_size; | |
209 p = &s->head[n]; | |
210 do { | |
211 m = *--p; | |
212 *p = (Pos)(m >= wsize ? m - wsize : NIL); | |
213 } while (--n); | |
214 n = wsize; | |
215 #ifndef FASTEST | |
216 p = &s->prev[n]; | |
217 do { | |
218 m = *--p; | |
219 *p = (Pos)(m >= wsize ? m - wsize : NIL); | |
220 /* If n is not on any hash chain, prev[n] is garbage but | |
221 * its value will never be used. | |
222 */ | |
223 } while (--n); | |
224 #endif | |
225 } | |
226 | |
227 /* ========================================================================= */ | |
228 int ZEXPORT deflateInit_(strm, level, version, stream_size) | |
229 z_streamp strm; | |
230 int level; | |
231 const char *version; | |
232 int stream_size; | |
233 { | |
234 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, | |
235 Z_DEFAULT_STRATEGY, version, stream_size); | |
236 /* To do: ignore strm->next_in if we use it as window */ | |
237 } | |
238 | |
239 /* ========================================================================= */ | |
240 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, | |
241 version, stream_size) | |
242 z_streamp strm; | |
243 int level; | |
244 int method; | |
245 int windowBits; | |
246 int memLevel; | |
247 int strategy; | |
248 const char *version; | |
249 int stream_size; | |
250 { | |
251 deflate_state *s; | |
252 int wrap = 1; | |
253 static const char my_version[] = ZLIB_VERSION; | |
254 | |
255 ushf *overlay; | |
256 /* We overlay pending_buf and d_buf+l_buf. This works since the average | |
257 * output size for (length,distance) codes is <= 24 bits. | |
258 */ | |
259 | |
260 if (version == Z_NULL || version[0] != my_version[0] || | |
261 stream_size != sizeof(z_stream)) { | |
262 return Z_VERSION_ERROR; | |
263 } | |
264 if (strm == Z_NULL) return Z_STREAM_ERROR; | |
265 | |
266 strm->msg = Z_NULL; | |
267 if (strm->zalloc == (alloc_func)0) { | |
268 #ifdef Z_SOLO | |
269 return Z_STREAM_ERROR; | |
270 #else | |
271 strm->zalloc = zcalloc; | |
272 strm->opaque = (voidpf)0; | |
273 #endif | |
274 } | |
275 if (strm->zfree == (free_func)0) | |
276 #ifdef Z_SOLO | |
277 return Z_STREAM_ERROR; | |
278 #else | |
279 strm->zfree = zcfree; | |
280 #endif | |
281 | |
282 #ifdef FASTEST | |
283 if (level != 0) level = 1; | |
284 #else | |
285 if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
286 #endif | |
287 | |
288 if (windowBits < 0) { /* suppress zlib wrapper */ | |
289 wrap = 0; | |
290 windowBits = -windowBits; | |
291 } | |
292 #ifdef GZIP | |
293 else if (windowBits > 15) { | |
294 wrap = 2; /* write gzip wrapper instead */ | |
295 windowBits -= 16; | |
296 } | |
297 #endif | |
298 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || | |
299 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || | |
300 strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) { | |
301 return Z_STREAM_ERROR; | |
302 } | |
303 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ | |
304 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); | |
305 if (s == Z_NULL) return Z_MEM_ERROR; | |
306 strm->state = (struct internal_state FAR *)s; | |
307 s->strm = strm; | |
308 s->status = INIT_STATE; /* to pass state test in deflateReset() */ | |
309 | |
310 s->wrap = wrap; | |
311 s->gzhead = Z_NULL; | |
312 s->w_bits = (uInt)windowBits; | |
313 s->w_size = 1 << s->w_bits; | |
314 s->w_mask = s->w_size - 1; | |
315 | |
316 s->hash_bits = (uInt)memLevel + 7; | |
317 s->hash_size = 1 << s->hash_bits; | |
318 s->hash_mask = s->hash_size - 1; | |
319 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); | |
320 | |
321 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); | |
322 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); | |
323 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); | |
324 | |
325 s->high_water = 0; /* nothing written to s->window yet */ | |
326 | |
327 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ | |
328 | |
329 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); | |
330 s->pending_buf = (uchf *) overlay; | |
331 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); | |
332 | |
333 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || | |
334 s->pending_buf == Z_NULL) { | |
335 s->status = FINISH_STATE; | |
336 strm->msg = ERR_MSG(Z_MEM_ERROR); | |
337 deflateEnd (strm); | |
338 return Z_MEM_ERROR; | |
339 } | |
340 s->d_buf = overlay + s->lit_bufsize/sizeof(ush); | |
341 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; | |
342 | |
343 s->level = level; | |
344 s->strategy = strategy; | |
345 s->method = (Byte)method; | |
346 | |
347 return deflateReset(strm); | |
348 } | |
349 | |
350 /* ========================================================================= | |
351 * Check for a valid deflate stream state. Return 0 if ok, 1 if not. | |
352 */ | |
353 local int deflateStateCheck (strm) | |
354 z_streamp strm; | |
355 { | |
356 deflate_state *s; | |
357 if (strm == Z_NULL || | |
358 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) | |
359 return 1; | |
360 s = strm->state; | |
361 if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE && | |
362 #ifdef GZIP | |
363 s->status != GZIP_STATE && | |
364 #endif | |
365 s->status != EXTRA_STATE && | |
366 s->status != NAME_STATE && | |
367 s->status != COMMENT_STATE && | |
368 s->status != HCRC_STATE && | |
369 s->status != BUSY_STATE && | |
370 s->status != FINISH_STATE)) | |
371 return 1; | |
372 return 0; | |
373 } | |
374 | |
375 /* ========================================================================= */ | |
376 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) | |
377 z_streamp strm; | |
378 const Bytef *dictionary; | |
379 uInt dictLength; | |
380 { | |
381 deflate_state *s; | |
382 uInt str, n; | |
383 int wrap; | |
384 unsigned avail; | |
385 z_const unsigned char *next; | |
386 | |
387 if (deflateStateCheck(strm) || dictionary == Z_NULL) | |
388 return Z_STREAM_ERROR; | |
389 s = strm->state; | |
390 wrap = s->wrap; | |
391 if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) | |
392 return Z_STREAM_ERROR; | |
393 | |
394 /* when using zlib wrappers, compute Adler-32 for provided dictionary */ | |
395 if (wrap == 1) | |
396 strm->adler = adler32(strm->adler, dictionary, dictLength); | |
397 s->wrap = 0; /* avoid computing Adler-32 in read_buf */ | |
398 | |
399 /* if dictionary would fill window, just replace the history */ | |
400 if (dictLength >= s->w_size) { | |
401 if (wrap == 0) { /* already empty otherwise */ | |
402 CLEAR_HASH(s); | |
403 s->strstart = 0; | |
404 s->block_start = 0L; | |
405 s->insert = 0; | |
406 } | |
407 dictionary += dictLength - s->w_size; /* use the tail */ | |
408 dictLength = s->w_size; | |
409 } | |
410 | |
411 /* insert dictionary into window and hash */ | |
412 avail = strm->avail_in; | |
413 next = strm->next_in; | |
414 strm->avail_in = dictLength; | |
415 strm->next_in = (z_const Bytef *)dictionary; | |
416 fill_window(s); | |
417 while (s->lookahead >= MIN_MATCH) { | |
418 str = s->strstart; | |
419 n = s->lookahead - (MIN_MATCH-1); | |
420 do { | |
421 UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); | |
422 #ifndef FASTEST | |
423 s->prev[str & s->w_mask] = s->head[s->ins_h]; | |
424 #endif | |
425 s->head[s->ins_h] = (Pos)str; | |
426 str++; | |
427 } while (--n); | |
428 s->strstart = str; | |
429 s->lookahead = MIN_MATCH-1; | |
430 fill_window(s); | |
431 } | |
432 s->strstart += s->lookahead; | |
433 s->block_start = (long)s->strstart; | |
434 s->insert = s->lookahead; | |
435 s->lookahead = 0; | |
436 s->match_length = s->prev_length = MIN_MATCH-1; | |
437 s->match_available = 0; | |
438 strm->next_in = next; | |
439 strm->avail_in = avail; | |
440 s->wrap = wrap; | |
441 return Z_OK; | |
442 } | |
443 | |
444 /* ========================================================================= */ | |
445 int ZEXPORT deflateGetDictionary (strm, dictionary, dictLength) | |
446 z_streamp strm; | |
447 Bytef *dictionary; | |
448 uInt *dictLength; | |
449 { | |
450 deflate_state *s; | |
451 uInt len; | |
452 | |
453 if (deflateStateCheck(strm)) | |
454 return Z_STREAM_ERROR; | |
455 s = strm->state; | |
456 len = s->strstart + s->lookahead; | |
457 if (len > s->w_size) | |
458 len = s->w_size; | |
459 if (dictionary != Z_NULL && len) | |
460 zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len); | |
461 if (dictLength != Z_NULL) | |
462 *dictLength = len; | |
463 return Z_OK; | |
464 } | |
465 | |
466 /* ========================================================================= */ | |
467 int ZEXPORT deflateResetKeep (strm) | |
468 z_streamp strm; | |
469 { | |
470 deflate_state *s; | |
471 | |
472 if (deflateStateCheck(strm)) { | |
473 return Z_STREAM_ERROR; | |
474 } | |
475 | |
476 strm->total_in = strm->total_out = 0; | |
477 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ | |
478 strm->data_type = Z_UNKNOWN; | |
479 | |
480 s = (deflate_state *)strm->state; | |
481 s->pending = 0; | |
482 s->pending_out = s->pending_buf; | |
483 | |
484 if (s->wrap < 0) { | |
485 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ | |
486 } | |
487 s->status = | |
488 #ifdef GZIP | |
489 s->wrap == 2 ? GZIP_STATE : | |
490 #endif | |
491 s->wrap ? INIT_STATE : BUSY_STATE; | |
492 strm->adler = | |
493 #ifdef GZIP | |
494 s->wrap == 2 ? crc32(0L, Z_NULL, 0) : | |
495 #endif | |
496 adler32(0L, Z_NULL, 0); | |
497 s->last_flush = Z_NO_FLUSH; | |
498 | |
499 _tr_init(s); | |
500 | |
501 return Z_OK; | |
502 } | |
503 | |
504 /* ========================================================================= */ | |
505 int ZEXPORT deflateReset (strm) | |
506 z_streamp strm; | |
507 { | |
508 int ret; | |
509 | |
510 ret = deflateResetKeep(strm); | |
511 if (ret == Z_OK) | |
512 lm_init(strm->state); | |
513 return ret; | |
514 } | |
515 | |
516 /* ========================================================================= */ | |
517 int ZEXPORT deflateSetHeader (strm, head) | |
518 z_streamp strm; | |
519 gz_headerp head; | |
520 { | |
521 if (deflateStateCheck(strm) || strm->state->wrap != 2) | |
522 return Z_STREAM_ERROR; | |
523 strm->state->gzhead = head; | |
524 return Z_OK; | |
525 } | |
526 | |
527 /* ========================================================================= */ | |
528 int ZEXPORT deflatePending (strm, pending, bits) | |
529 unsigned *pending; | |
530 int *bits; | |
531 z_streamp strm; | |
532 { | |
533 if (deflateStateCheck(strm)) return Z_STREAM_ERROR; | |
534 if (pending != Z_NULL) | |
535 *pending = strm->state->pending; | |
536 if (bits != Z_NULL) | |
537 *bits = strm->state->bi_valid; | |
538 return Z_OK; | |
539 } | |
540 | |
541 /* ========================================================================= */ | |
542 int ZEXPORT deflatePrime (strm, bits, value) | |
543 z_streamp strm; | |
544 int bits; | |
545 int value; | |
546 { | |
547 deflate_state *s; | |
548 int put; | |
549 | |
550 if (deflateStateCheck(strm)) return Z_STREAM_ERROR; | |
551 s = strm->state; | |
552 if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3)) | |
553 return Z_BUF_ERROR; | |
554 do { | |
555 put = Buf_size - s->bi_valid; | |
556 if (put > bits) | |
557 put = bits; | |
558 s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); | |
559 s->bi_valid += put; | |
560 _tr_flush_bits(s); | |
561 value >>= put; | |
562 bits -= put; | |
563 } while (bits); | |
564 return Z_OK; | |
565 } | |
566 | |
567 /* ========================================================================= */ | |
568 int ZEXPORT deflateParams(strm, level, strategy) | |
569 z_streamp strm; | |
570 int level; | |
571 int strategy; | |
572 { | |
573 deflate_state *s; | |
574 compress_func func; | |
575 | |
576 if (deflateStateCheck(strm)) return Z_STREAM_ERROR; | |
577 s = strm->state; | |
578 | |
579 #ifdef FASTEST | |
580 if (level != 0) level = 1; | |
581 #else | |
582 if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
583 #endif | |
584 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { | |
585 return Z_STREAM_ERROR; | |
586 } | |
587 func = configuration_table[s->level].func; | |
588 | |
589 if ((strategy != s->strategy || func != configuration_table[level].func) && | |
590 s->high_water) { | |
591 /* Flush the last buffer: */ | |
592 int err = deflate(strm, Z_BLOCK); | |
593 if (err == Z_STREAM_ERROR) | |
594 return err; | |
595 if (strm->avail_out == 0) | |
596 return Z_BUF_ERROR; | |
597 } | |
598 if (s->level != level) { | |
599 if (s->level == 0 && s->matches != 0) { | |
600 if (s->matches == 1) | |
601 slide_hash(s); | |
602 else | |
603 CLEAR_HASH(s); | |
604 s->matches = 0; | |
605 } | |
606 s->level = level; | |
607 s->max_lazy_match = configuration_table[level].max_lazy; | |
608 s->good_match = configuration_table[level].good_length; | |
609 s->nice_match = configuration_table[level].nice_length; | |
610 s->max_chain_length = configuration_table[level].max_chain; | |
611 } | |
612 s->strategy = strategy; | |
613 return Z_OK; | |
614 } | |
615 | |
616 /* ========================================================================= */ | |
617 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) | |
618 z_streamp strm; | |
619 int good_length; | |
620 int max_lazy; | |
621 int nice_length; | |
622 int max_chain; | |
623 { | |
624 deflate_state *s; | |
625 | |
626 if (deflateStateCheck(strm)) return Z_STREAM_ERROR; | |
627 s = strm->state; | |
628 s->good_match = (uInt)good_length; | |
629 s->max_lazy_match = (uInt)max_lazy; | |
630 s->nice_match = nice_length; | |
631 s->max_chain_length = (uInt)max_chain; | |
632 return Z_OK; | |
633 } | |
634 | |
635 /* ========================================================================= | |
636 * For the default windowBits of 15 and memLevel of 8, this function returns | |
637 * a close to exact, as well as small, upper bound on the compressed size. | |
638 * They are coded as constants here for a reason--if the #define's are | |
639 * changed, then this function needs to be changed as well. The return | |
640 * value for 15 and 8 only works for those exact settings. | |
641 * | |
642 * For any setting other than those defaults for windowBits and memLevel, | |
643 * the value returned is a conservative worst case for the maximum expansion | |
644 * resulting from using fixed blocks instead of stored blocks, which deflate | |
645 * can emit on compressed data for some combinations of the parameters. | |
646 * | |
647 * This function could be more sophisticated to provide closer upper bounds for | |
648 * every combination of windowBits and memLevel. But even the conservative | |
649 * upper bound of about 14% expansion does not seem onerous for output buffer | |
650 * allocation. | |
651 */ | |
652 uLong ZEXPORT deflateBound(strm, sourceLen) | |
653 z_streamp strm; | |
654 uLong sourceLen; | |
655 { | |
656 deflate_state *s; | |
657 uLong complen, wraplen; | |
658 | |
659 /* conservative upper bound for compressed data */ | |
660 complen = sourceLen + | |
661 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; | |
662 | |
663 /* if can't get parameters, return conservative bound plus zlib wrapper */ | |
664 if (deflateStateCheck(strm)) | |
665 return complen + 6; | |
666 | |
667 /* compute wrapper length */ | |
668 s = strm->state; | |
669 switch (s->wrap) { | |
670 case 0: /* raw deflate */ | |
671 wraplen = 0; | |
672 break; | |
673 case 1: /* zlib wrapper */ | |
674 wraplen = 6 + (s->strstart ? 4 : 0); | |
675 break; | |
676 #ifdef GZIP | |
677 case 2: /* gzip wrapper */ | |
678 wraplen = 18; | |
679 if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ | |
680 Bytef *str; | |
681 if (s->gzhead->extra != Z_NULL) | |
682 wraplen += 2 + s->gzhead->extra_len; | |
683 str = s->gzhead->name; | |
684 if (str != Z_NULL) | |
685 do { | |
686 wraplen++; | |
687 } while (*str++); | |
688 str = s->gzhead->comment; | |
689 if (str != Z_NULL) | |
690 do { | |
691 wraplen++; | |
692 } while (*str++); | |
693 if (s->gzhead->hcrc) | |
694 wraplen += 2; | |
695 } | |
696 break; | |
697 #endif | |
698 default: /* for compiler happiness */ | |
699 wraplen = 6; | |
700 } | |
701 | |
702 /* if not default parameters, return conservative bound */ | |
703 if (s->w_bits != 15 || s->hash_bits != 8 + 7) | |
704 return complen + wraplen; | |
705 | |
706 /* default settings: return tight bound for that case */ | |
707 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + | |
708 (sourceLen >> 25) + 13 - 6 + wraplen; | |
709 } | |
710 | |
711 /* ========================================================================= | |
712 * Put a short in the pending buffer. The 16-bit value is put in MSB order. | |
713 * IN assertion: the stream state is correct and there is enough room in | |
714 * pending_buf. | |
715 */ | |
716 local void putShortMSB (s, b) | |
717 deflate_state *s; | |
718 uInt b; | |
719 { | |
720 put_byte(s, (Byte)(b >> 8)); | |
721 put_byte(s, (Byte)(b & 0xff)); | |
722 } | |
723 | |
724 /* ========================================================================= | |
725 * Flush as much pending output as possible. All deflate() output, except for | |
726 * some deflate_stored() output, goes through this function so some | |
727 * applications may wish to modify it to avoid allocating a large | |
728 * strm->next_out buffer and copying into it. (See also read_buf()). | |
729 */ | |
730 local void flush_pending(strm) | |
731 z_streamp strm; | |
732 { | |
733 unsigned len; | |
734 deflate_state *s = strm->state; | |
735 | |
736 _tr_flush_bits(s); | |
737 len = s->pending; | |
738 if (len > strm->avail_out) len = strm->avail_out; | |
739 if (len == 0) return; | |
740 | |
741 zmemcpy(strm->next_out, s->pending_out, len); | |
742 strm->next_out += len; | |
743 s->pending_out += len; | |
744 strm->total_out += len; | |
745 strm->avail_out -= len; | |
746 s->pending -= len; | |
747 if (s->pending == 0) { | |
748 s->pending_out = s->pending_buf; | |
749 } | |
750 } | |
751 | |
752 /* =========================================================================== | |
753 * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1]. | |
754 */ | |
755 #define HCRC_UPDATE(beg) \ | |
756 do { \ | |
757 if (s->gzhead->hcrc && s->pending > (beg)) \ | |
758 strm->adler = crc32(strm->adler, s->pending_buf + (beg), \ | |
759 s->pending - (beg)); \ | |
760 } while (0) | |
761 | |
762 /* ========================================================================= */ | |
763 int ZEXPORT deflate (strm, flush) | |
764 z_streamp strm; | |
765 int flush; | |
766 { | |
767 int old_flush; /* value of flush param for previous deflate call */ | |
768 deflate_state *s; | |
769 | |
770 if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { | |
771 return Z_STREAM_ERROR; | |
772 } | |
773 s = strm->state; | |
774 | |
775 if (strm->next_out == Z_NULL || | |
776 (strm->avail_in != 0 && strm->next_in == Z_NULL) || | |
777 (s->status == FINISH_STATE && flush != Z_FINISH)) { | |
778 ERR_RETURN(strm, Z_STREAM_ERROR); | |
779 } | |
780 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); | |
781 | |
782 old_flush = s->last_flush; | |
783 s->last_flush = flush; | |
784 | |
785 /* Flush as much pending output as possible */ | |
786 if (s->pending != 0) { | |
787 flush_pending(strm); | |
788 if (strm->avail_out == 0) { | |
789 /* Since avail_out is 0, deflate will be called again with | |
790 * more output space, but possibly with both pending and | |
791 * avail_in equal to zero. There won't be anything to do, | |
792 * but this is not an error situation so make sure we | |
793 * return OK instead of BUF_ERROR at next call of deflate: | |
794 */ | |
795 s->last_flush = -1; | |
796 return Z_OK; | |
797 } | |
798 | |
799 /* Make sure there is something to do and avoid duplicate consecutive | |
800 * flushes. For repeated and useless calls with Z_FINISH, we keep | |
801 * returning Z_STREAM_END instead of Z_BUF_ERROR. | |
802 */ | |
803 } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && | |
804 flush != Z_FINISH) { | |
805 ERR_RETURN(strm, Z_BUF_ERROR); | |
806 } | |
807 | |
808 /* User must not provide more input after the first FINISH: */ | |
809 if (s->status == FINISH_STATE && strm->avail_in != 0) { | |
810 ERR_RETURN(strm, Z_BUF_ERROR); | |
811 } | |
812 | |
813 /* Write the header */ | |
814 if (s->status == INIT_STATE) { | |
815 /* zlib header */ | |
816 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; | |
817 uInt level_flags; | |
818 | |
819 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) | |
820 level_flags = 0; | |
821 else if (s->level < 6) | |
822 level_flags = 1; | |
823 else if (s->level == 6) | |
824 level_flags = 2; | |
825 else | |
826 level_flags = 3; | |
827 header |= (level_flags << 6); | |
828 if (s->strstart != 0) header |= PRESET_DICT; | |
829 header += 31 - (header % 31); | |
830 | |
831 putShortMSB(s, header); | |
832 | |
833 /* Save the adler32 of the preset dictionary: */ | |
834 if (s->strstart != 0) { | |
835 putShortMSB(s, (uInt)(strm->adler >> 16)); | |
836 putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
837 } | |
838 strm->adler = adler32(0L, Z_NULL, 0); | |
839 s->status = BUSY_STATE; | |
840 | |
841 /* Compression must start with an empty pending buffer */ | |
842 flush_pending(strm); | |
843 if (s->pending != 0) { | |
844 s->last_flush = -1; | |
845 return Z_OK; | |
846 } | |
847 } | |
848 #ifdef GZIP | |
849 if (s->status == GZIP_STATE) { | |
850 /* gzip header */ | |
851 strm->adler = crc32(0L, Z_NULL, 0); | |
852 put_byte(s, 31); | |
853 put_byte(s, 139); | |
854 put_byte(s, 8); | |
855 if (s->gzhead == Z_NULL) { | |
856 put_byte(s, 0); | |
857 put_byte(s, 0); | |
858 put_byte(s, 0); | |
859 put_byte(s, 0); | |
860 put_byte(s, 0); | |
861 put_byte(s, s->level == 9 ? 2 : | |
862 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
863 4 : 0)); | |
864 put_byte(s, OS_CODE); | |
865 s->status = BUSY_STATE; | |
866 | |
867 /* Compression must start with an empty pending buffer */ | |
868 flush_pending(strm); | |
869 if (s->pending != 0) { | |
870 s->last_flush = -1; | |
871 return Z_OK; | |
872 } | |
873 } | |
874 else { | |
875 put_byte(s, (s->gzhead->text ? 1 : 0) + | |
876 (s->gzhead->hcrc ? 2 : 0) + | |
877 (s->gzhead->extra == Z_NULL ? 0 : 4) + | |
878 (s->gzhead->name == Z_NULL ? 0 : 8) + | |
879 (s->gzhead->comment == Z_NULL ? 0 : 16) | |
880 ); | |
881 put_byte(s, (Byte)(s->gzhead->time & 0xff)); | |
882 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); | |
883 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); | |
884 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); | |
885 put_byte(s, s->level == 9 ? 2 : | |
886 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
887 4 : 0)); | |
888 put_byte(s, s->gzhead->os & 0xff); | |
889 if (s->gzhead->extra != Z_NULL) { | |
890 put_byte(s, s->gzhead->extra_len & 0xff); | |
891 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); | |
892 } | |
893 if (s->gzhead->hcrc) | |
894 strm->adler = crc32(strm->adler, s->pending_buf, | |
895 s->pending); | |
896 s->gzindex = 0; | |
897 s->status = EXTRA_STATE; | |
898 } | |
899 } | |
900 if (s->status == EXTRA_STATE) { | |
901 if (s->gzhead->extra != Z_NULL) { | |
902 ulg beg = s->pending; /* start of bytes to update crc */ | |
903 uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex; | |
904 while (s->pending + left > s->pending_buf_size) { | |
905 uInt copy = s->pending_buf_size - s->pending; | |
906 zmemcpy(s->pending_buf + s->pending, | |
907 s->gzhead->extra + s->gzindex, copy); | |
908 s->pending = s->pending_buf_size; | |
909 HCRC_UPDATE(beg); | |
910 s->gzindex += copy; | |
911 flush_pending(strm); | |
912 if (s->pending != 0) { | |
913 s->last_flush = -1; | |
914 return Z_OK; | |
915 } | |
916 beg = 0; | |
917 left -= copy; | |
918 } | |
919 zmemcpy(s->pending_buf + s->pending, | |
920 s->gzhead->extra + s->gzindex, left); | |
921 s->pending += left; | |
922 HCRC_UPDATE(beg); | |
923 s->gzindex = 0; | |
924 } | |
925 s->status = NAME_STATE; | |
926 } | |
927 if (s->status == NAME_STATE) { | |
928 if (s->gzhead->name != Z_NULL) { | |
929 ulg beg = s->pending; /* start of bytes to update crc */ | |
930 int val; | |
931 do { | |
932 if (s->pending == s->pending_buf_size) { | |
933 HCRC_UPDATE(beg); | |
934 flush_pending(strm); | |
935 if (s->pending != 0) { | |
936 s->last_flush = -1; | |
937 return Z_OK; | |
938 } | |
939 beg = 0; | |
940 } | |
941 val = s->gzhead->name[s->gzindex++]; | |
942 put_byte(s, val); | |
943 } while (val != 0); | |
944 HCRC_UPDATE(beg); | |
945 s->gzindex = 0; | |
946 } | |
947 s->status = COMMENT_STATE; | |
948 } | |
949 if (s->status == COMMENT_STATE) { | |
950 if (s->gzhead->comment != Z_NULL) { | |
951 ulg beg = s->pending; /* start of bytes to update crc */ | |
952 int val; | |
953 do { | |
954 if (s->pending == s->pending_buf_size) { | |
955 HCRC_UPDATE(beg); | |
956 flush_pending(strm); | |
957 if (s->pending != 0) { | |
958 s->last_flush = -1; | |
959 return Z_OK; | |
960 } | |
961 beg = 0; | |
962 } | |
963 val = s->gzhead->comment[s->gzindex++]; | |
964 put_byte(s, val); | |
965 } while (val != 0); | |
966 HCRC_UPDATE(beg); | |
967 } | |
968 s->status = HCRC_STATE; | |
969 } | |
970 if (s->status == HCRC_STATE) { | |
971 if (s->gzhead->hcrc) { | |
972 if (s->pending + 2 > s->pending_buf_size) { | |
973 flush_pending(strm); | |
974 if (s->pending != 0) { | |
975 s->last_flush = -1; | |
976 return Z_OK; | |
977 } | |
978 } | |
979 put_byte(s, (Byte)(strm->adler & 0xff)); | |
980 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
981 strm->adler = crc32(0L, Z_NULL, 0); | |
982 } | |
983 s->status = BUSY_STATE; | |
984 | |
985 /* Compression must start with an empty pending buffer */ | |
986 flush_pending(strm); | |
987 if (s->pending != 0) { | |
988 s->last_flush = -1; | |
989 return Z_OK; | |
990 } | |
991 } | |
992 #endif | |
993 | |
994 /* Start a new block or continue the current one. | |
995 */ | |
996 if (strm->avail_in != 0 || s->lookahead != 0 || | |
997 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { | |
998 block_state bstate; | |
999 | |
1000 bstate = s->level == 0 ? deflate_stored(s, flush) : | |
1001 s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : | |
1002 s->strategy == Z_RLE ? deflate_rle(s, flush) : | |
1003 (*(configuration_table[s->level].func))(s, flush); | |
1004 | |
1005 if (bstate == finish_started || bstate == finish_done) { | |
1006 s->status = FINISH_STATE; | |
1007 } | |
1008 if (bstate == need_more || bstate == finish_started) { | |
1009 if (strm->avail_out == 0) { | |
1010 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ | |
1011 } | |
1012 return Z_OK; | |
1013 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call | |
1014 * of deflate should use the same flush parameter to make sure | |
1015 * that the flush is complete. So we don't have to output an | |
1016 * empty block here, this will be done at next call. This also | |
1017 * ensures that for a very small output buffer, we emit at most | |
1018 * one empty block. | |
1019 */ | |
1020 } | |
1021 if (bstate == block_done) { | |
1022 if (flush == Z_PARTIAL_FLUSH) { | |
1023 _tr_align(s); | |
1024 } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ | |
1025 _tr_stored_block(s, (char*)0, 0L, 0); | |
1026 /* For a full flush, this empty block will be recognized | |
1027 * as a special marker by inflate_sync(). | |
1028 */ | |
1029 if (flush == Z_FULL_FLUSH) { | |
1030 CLEAR_HASH(s); /* forget history */ | |
1031 if (s->lookahead == 0) { | |
1032 s->strstart = 0; | |
1033 s->block_start = 0L; | |
1034 s->insert = 0; | |
1035 } | |
1036 } | |
1037 } | |
1038 flush_pending(strm); | |
1039 if (strm->avail_out == 0) { | |
1040 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ | |
1041 return Z_OK; | |
1042 } | |
1043 } | |
1044 } | |
1045 | |
1046 if (flush != Z_FINISH) return Z_OK; | |
1047 if (s->wrap <= 0) return Z_STREAM_END; | |
1048 | |
1049 /* Write the trailer */ | |
1050 #ifdef GZIP | |
1051 if (s->wrap == 2) { | |
1052 put_byte(s, (Byte)(strm->adler & 0xff)); | |
1053 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
1054 put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); | |
1055 put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); | |
1056 put_byte(s, (Byte)(strm->total_in & 0xff)); | |
1057 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); | |
1058 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); | |
1059 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); | |
1060 } | |
1061 else | |
1062 #endif | |
1063 { | |
1064 putShortMSB(s, (uInt)(strm->adler >> 16)); | |
1065 putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
1066 } | |
1067 flush_pending(strm); | |
1068 /* If avail_out is zero, the application will call deflate again | |
1069 * to flush the rest. | |
1070 */ | |
1071 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ | |
1072 return s->pending != 0 ? Z_OK : Z_STREAM_END; | |
1073 } | |
1074 | |
1075 /* ========================================================================= */ | |
1076 int ZEXPORT deflateEnd (strm) | |
1077 z_streamp strm; | |
1078 { | |
1079 int status; | |
1080 | |
1081 if (deflateStateCheck(strm)) return Z_STREAM_ERROR; | |
1082 | |
1083 status = strm->state->status; | |
1084 | |
1085 /* Deallocate in reverse order of allocations: */ | |
1086 TRY_FREE(strm, strm->state->pending_buf); | |
1087 TRY_FREE(strm, strm->state->head); | |
1088 TRY_FREE(strm, strm->state->prev); | |
1089 TRY_FREE(strm, strm->state->window); | |
1090 | |
1091 ZFREE(strm, strm->state); | |
1092 strm->state = Z_NULL; | |
1093 | |
1094 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; | |
1095 } | |
1096 | |
1097 /* ========================================================================= | |
1098 * Copy the source state to the destination state. | |
1099 * To simplify the source, this is not supported for 16-bit MSDOS (which | |
1100 * doesn't have enough memory anyway to duplicate compression states). | |
1101 */ | |
1102 int ZEXPORT deflateCopy (dest, source) | |
1103 z_streamp dest; | |
1104 z_streamp source; | |
1105 { | |
1106 #ifdef MAXSEG_64K | |
1107 return Z_STREAM_ERROR; | |
1108 #else | |
1109 deflate_state *ds; | |
1110 deflate_state *ss; | |
1111 ushf *overlay; | |
1112 | |
1113 | |
1114 if (deflateStateCheck(source) || dest == Z_NULL) { | |
1115 return Z_STREAM_ERROR; | |
1116 } | |
1117 | |
1118 ss = source->state; | |
1119 | |
1120 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); | |
1121 | |
1122 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); | |
1123 if (ds == Z_NULL) return Z_MEM_ERROR; | |
1124 dest->state = (struct internal_state FAR *) ds; | |
1125 zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state)); | |
1126 ds->strm = dest; | |
1127 | |
1128 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); | |
1129 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); | |
1130 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); | |
1131 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); | |
1132 ds->pending_buf = (uchf *) overlay; | |
1133 | |
1134 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || | |
1135 ds->pending_buf == Z_NULL) { | |
1136 deflateEnd (dest); | |
1137 return Z_MEM_ERROR; | |
1138 } | |
1139 /* following zmemcpy do not work for 16-bit MSDOS */ | |
1140 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); | |
1141 zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos)); | |
1142 zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos)); | |
1143 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); | |
1144 | |
1145 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); | |
1146 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); | |
1147 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; | |
1148 | |
1149 ds->l_desc.dyn_tree = ds->dyn_ltree; | |
1150 ds->d_desc.dyn_tree = ds->dyn_dtree; | |
1151 ds->bl_desc.dyn_tree = ds->bl_tree; | |
1152 | |
1153 return Z_OK; | |
1154 #endif /* MAXSEG_64K */ | |
1155 } | |
1156 | |
1157 /* =========================================================================== | |
1158 * Read a new buffer from the current input stream, update the adler32 | |
1159 * and total number of bytes read. All deflate() input goes through | |
1160 * this function so some applications may wish to modify it to avoid | |
1161 * allocating a large strm->next_in buffer and copying from it. | |
1162 * (See also flush_pending()). | |
1163 */ | |
1164 local unsigned read_buf(strm, buf, size) | |
1165 z_streamp strm; | |
1166 Bytef *buf; | |
1167 unsigned size; | |
1168 { | |
1169 unsigned len = strm->avail_in; | |
1170 | |
1171 if (len > size) len = size; | |
1172 if (len == 0) return 0; | |
1173 | |
1174 strm->avail_in -= len; | |
1175 | |
1176 zmemcpy(buf, strm->next_in, len); | |
1177 if (strm->state->wrap == 1) { | |
1178 strm->adler = adler32(strm->adler, buf, len); | |
1179 } | |
1180 #ifdef GZIP | |
1181 else if (strm->state->wrap == 2) { | |
1182 strm->adler = crc32(strm->adler, buf, len); | |
1183 } | |
1184 #endif | |
1185 strm->next_in += len; | |
1186 strm->total_in += len; | |
1187 | |
1188 return len; | |
1189 } | |
1190 | |
1191 /* =========================================================================== | |
1192 * Initialize the "longest match" routines for a new zlib stream | |
1193 */ | |
1194 local void lm_init (s) | |
1195 deflate_state *s; | |
1196 { | |
1197 s->window_size = (ulg)2L*s->w_size; | |
1198 | |
1199 CLEAR_HASH(s); | |
1200 | |
1201 /* Set the default configuration parameters: | |
1202 */ | |
1203 s->max_lazy_match = configuration_table[s->level].max_lazy; | |
1204 s->good_match = configuration_table[s->level].good_length; | |
1205 s->nice_match = configuration_table[s->level].nice_length; | |
1206 s->max_chain_length = configuration_table[s->level].max_chain; | |
1207 | |
1208 s->strstart = 0; | |
1209 s->block_start = 0L; | |
1210 s->lookahead = 0; | |
1211 s->insert = 0; | |
1212 s->match_length = s->prev_length = MIN_MATCH-1; | |
1213 s->match_available = 0; | |
1214 s->ins_h = 0; | |
1215 #ifndef FASTEST | |
1216 #ifdef ASMV | |
1217 match_init(); /* initialize the asm code */ | |
1218 #endif | |
1219 #endif | |
1220 } | |
1221 | |
1222 #ifndef FASTEST | |
1223 /* =========================================================================== | |
1224 * Set match_start to the longest match starting at the given string and | |
1225 * return its length. Matches shorter or equal to prev_length are discarded, | |
1226 * in which case the result is equal to prev_length and match_start is | |
1227 * garbage. | |
1228 * IN assertions: cur_match is the head of the hash chain for the current | |
1229 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | |
1230 * OUT assertion: the match length is not greater than s->lookahead. | |
1231 */ | |
1232 #ifndef ASMV | |
1233 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or | |
1234 * match.S. The code will be functionally equivalent. | |
1235 */ | |
1236 local uInt longest_match(s, cur_match) | |
1237 deflate_state *s; | |
1238 IPos cur_match; /* current match */ | |
1239 { | |
1240 unsigned chain_length = s->max_chain_length;/* max hash chain length */ | |
1241 register Bytef *scan = s->window + s->strstart; /* current string */ | |
1242 register Bytef *match; /* matched string */ | |
1243 register int len; /* length of current match */ | |
1244 int best_len = (int)s->prev_length; /* best match length so far */ | |
1245 int nice_match = s->nice_match; /* stop if match long enough */ | |
1246 IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | |
1247 s->strstart - (IPos)MAX_DIST(s) : NIL; | |
1248 /* Stop when cur_match becomes <= limit. To simplify the code, | |
1249 * we prevent matches with the string of window index 0. | |
1250 */ | |
1251 Posf *prev = s->prev; | |
1252 uInt wmask = s->w_mask; | |
1253 | |
1254 #ifdef UNALIGNED_OK | |
1255 /* Compare two bytes at a time. Note: this is not always beneficial. | |
1256 * Try with and without -DUNALIGNED_OK to check. | |
1257 */ | |
1258 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; | |
1259 register ush scan_start = *(ushf*)scan; | |
1260 register ush scan_end = *(ushf*)(scan+best_len-1); | |
1261 #else | |
1262 register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1263 register Byte scan_end1 = scan[best_len-1]; | |
1264 register Byte scan_end = scan[best_len]; | |
1265 #endif | |
1266 | |
1267 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1268 * It is easy to get rid of this optimization if necessary. | |
1269 */ | |
1270 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1271 | |
1272 /* Do not waste too much time if we already have a good match: */ | |
1273 if (s->prev_length >= s->good_match) { | |
1274 chain_length >>= 2; | |
1275 } | |
1276 /* Do not look for matches beyond the end of the input. This is necessary | |
1277 * to make deflate deterministic. | |
1278 */ | |
1279 if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead; | |
1280 | |
1281 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1282 | |
1283 do { | |
1284 Assert(cur_match < s->strstart, "no future"); | |
1285 match = s->window + cur_match; | |
1286 | |
1287 /* Skip to next match if the match length cannot increase | |
1288 * or if the match length is less than 2. Note that the checks below | |
1289 * for insufficient lookahead only occur occasionally for performance | |
1290 * reasons. Therefore uninitialized memory will be accessed, and | |
1291 * conditional jumps will be made that depend on those values. | |
1292 * However the length of the match is limited to the lookahead, so | |
1293 * the output of deflate is not affected by the uninitialized values. | |
1294 */ | |
1295 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) | |
1296 /* This code assumes sizeof(unsigned short) == 2. Do not use | |
1297 * UNALIGNED_OK if your compiler uses a different size. | |
1298 */ | |
1299 if (*(ushf*)(match+best_len-1) != scan_end || | |
1300 *(ushf*)match != scan_start) continue; | |
1301 | |
1302 /* It is not necessary to compare scan[2] and match[2] since they are | |
1303 * always equal when the other bytes match, given that the hash keys | |
1304 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at | |
1305 * strstart+3, +5, ... up to strstart+257. We check for insufficient | |
1306 * lookahead only every 4th comparison; the 128th check will be made | |
1307 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is | |
1308 * necessary to put more guard bytes at the end of the window, or | |
1309 * to check more often for insufficient lookahead. | |
1310 */ | |
1311 Assert(scan[2] == match[2], "scan[2]?"); | |
1312 scan++, match++; | |
1313 do { | |
1314 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1315 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1316 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1317 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1318 scan < strend); | |
1319 /* The funny "do {}" generates better code on most compilers */ | |
1320 | |
1321 /* Here, scan <= window+strstart+257 */ | |
1322 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1323 if (*scan == *match) scan++; | |
1324 | |
1325 len = (MAX_MATCH - 1) - (int)(strend-scan); | |
1326 scan = strend - (MAX_MATCH-1); | |
1327 | |
1328 #else /* UNALIGNED_OK */ | |
1329 | |
1330 if (match[best_len] != scan_end || | |
1331 match[best_len-1] != scan_end1 || | |
1332 *match != *scan || | |
1333 *++match != scan[1]) continue; | |
1334 | |
1335 /* The check at best_len-1 can be removed because it will be made | |
1336 * again later. (This heuristic is not always a win.) | |
1337 * It is not necessary to compare scan[2] and match[2] since they | |
1338 * are always equal when the other bytes match, given that | |
1339 * the hash keys are equal and that HASH_BITS >= 8. | |
1340 */ | |
1341 scan += 2, match++; | |
1342 Assert(*scan == *match, "match[2]?"); | |
1343 | |
1344 /* We check for insufficient lookahead only every 8th comparison; | |
1345 * the 256th check will be made at strstart+258. | |
1346 */ | |
1347 do { | |
1348 } while (*++scan == *++match && *++scan == *++match && | |
1349 *++scan == *++match && *++scan == *++match && | |
1350 *++scan == *++match && *++scan == *++match && | |
1351 *++scan == *++match && *++scan == *++match && | |
1352 scan < strend); | |
1353 | |
1354 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1355 | |
1356 len = MAX_MATCH - (int)(strend - scan); | |
1357 scan = strend - MAX_MATCH; | |
1358 | |
1359 #endif /* UNALIGNED_OK */ | |
1360 | |
1361 if (len > best_len) { | |
1362 s->match_start = cur_match; | |
1363 best_len = len; | |
1364 if (len >= nice_match) break; | |
1365 #ifdef UNALIGNED_OK | |
1366 scan_end = *(ushf*)(scan+best_len-1); | |
1367 #else | |
1368 scan_end1 = scan[best_len-1]; | |
1369 scan_end = scan[best_len]; | |
1370 #endif | |
1371 } | |
1372 } while ((cur_match = prev[cur_match & wmask]) > limit | |
1373 && --chain_length != 0); | |
1374 | |
1375 if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | |
1376 return s->lookahead; | |
1377 } | |
1378 #endif /* ASMV */ | |
1379 | |
1380 #else /* FASTEST */ | |
1381 | |
1382 /* --------------------------------------------------------------------------- | |
1383 * Optimized version for FASTEST only | |
1384 */ | |
1385 local uInt longest_match(s, cur_match) | |
1386 deflate_state *s; | |
1387 IPos cur_match; /* current match */ | |
1388 { | |
1389 register Bytef *scan = s->window + s->strstart; /* current string */ | |
1390 register Bytef *match; /* matched string */ | |
1391 register int len; /* length of current match */ | |
1392 register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1393 | |
1394 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1395 * It is easy to get rid of this optimization if necessary. | |
1396 */ | |
1397 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1398 | |
1399 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1400 | |
1401 Assert(cur_match < s->strstart, "no future"); | |
1402 | |
1403 match = s->window + cur_match; | |
1404 | |
1405 /* Return failure if the match length is less than 2: | |
1406 */ | |
1407 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; | |
1408 | |
1409 /* The check at best_len-1 can be removed because it will be made | |
1410 * again later. (This heuristic is not always a win.) | |
1411 * It is not necessary to compare scan[2] and match[2] since they | |
1412 * are always equal when the other bytes match, given that | |
1413 * the hash keys are equal and that HASH_BITS >= 8. | |
1414 */ | |
1415 scan += 2, match += 2; | |
1416 Assert(*scan == *match, "match[2]?"); | |
1417 | |
1418 /* We check for insufficient lookahead only every 8th comparison; | |
1419 * the 256th check will be made at strstart+258. | |
1420 */ | |
1421 do { | |
1422 } while (*++scan == *++match && *++scan == *++match && | |
1423 *++scan == *++match && *++scan == *++match && | |
1424 *++scan == *++match && *++scan == *++match && | |
1425 *++scan == *++match && *++scan == *++match && | |
1426 scan < strend); | |
1427 | |
1428 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1429 | |
1430 len = MAX_MATCH - (int)(strend - scan); | |
1431 | |
1432 if (len < MIN_MATCH) return MIN_MATCH - 1; | |
1433 | |
1434 s->match_start = cur_match; | |
1435 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; | |
1436 } | |
1437 | |
1438 #endif /* FASTEST */ | |
1439 | |
1440 #ifdef ZLIB_DEBUG | |
1441 | |
1442 #define EQUAL 0 | |
1443 /* result of memcmp for equal strings */ | |
1444 | |
1445 /* =========================================================================== | |
1446 * Check that the match at match_start is indeed a match. | |
1447 */ | |
1448 local void check_match(s, start, match, length) | |
1449 deflate_state *s; | |
1450 IPos start, match; | |
1451 int length; | |
1452 { | |
1453 /* check that the match is indeed a match */ | |
1454 if (zmemcmp(s->window + match, | |
1455 s->window + start, length) != EQUAL) { | |
1456 fprintf(stderr, " start %u, match %u, length %d\n", | |
1457 start, match, length); | |
1458 do { | |
1459 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); | |
1460 } while (--length != 0); | |
1461 z_error("invalid match"); | |
1462 } | |
1463 if (z_verbose > 1) { | |
1464 fprintf(stderr,"\\[%d,%d]", start-match, length); | |
1465 do { putc(s->window[start++], stderr); } while (--length != 0); | |
1466 } | |
1467 } | |
1468 #else | |
1469 # define check_match(s, start, match, length) | |
1470 #endif /* ZLIB_DEBUG */ | |
1471 | |
1472 /* =========================================================================== | |
1473 * Fill the window when the lookahead becomes insufficient. | |
1474 * Updates strstart and lookahead. | |
1475 * | |
1476 * IN assertion: lookahead < MIN_LOOKAHEAD | |
1477 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD | |
1478 * At least one byte has been read, or avail_in == 0; reads are | |
1479 * performed for at least two bytes (required for the zip translate_eol | |
1480 * option -- not supported here). | |
1481 */ | |
1482 local void fill_window(s) | |
1483 deflate_state *s; | |
1484 { | |
1485 unsigned n; | |
1486 unsigned more; /* Amount of free space at the end of the window. */ | |
1487 uInt wsize = s->w_size; | |
1488 | |
1489 Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); | |
1490 | |
1491 do { | |
1492 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); | |
1493 | |
1494 /* Deal with !@#$% 64K limit: */ | |
1495 if (sizeof(int) <= 2) { | |
1496 if (more == 0 && s->strstart == 0 && s->lookahead == 0) { | |
1497 more = wsize; | |
1498 | |
1499 } else if (more == (unsigned)(-1)) { | |
1500 /* Very unlikely, but possible on 16 bit machine if | |
1501 * strstart == 0 && lookahead == 1 (input done a byte at time) | |
1502 */ | |
1503 more--; | |
1504 } | |
1505 } | |
1506 | |
1507 /* If the window is almost full and there is insufficient lookahead, | |
1508 * move the upper half to the lower one to make room in the upper half. | |
1509 */ | |
1510 if (s->strstart >= wsize+MAX_DIST(s)) { | |
1511 | |
1512 zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more); | |
1513 s->match_start -= wsize; | |
1514 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ | |
1515 s->block_start -= (long) wsize; | |
1516 slide_hash(s); | |
1517 more += wsize; | |
1518 } | |
1519 if (s->strm->avail_in == 0) break; | |
1520 | |
1521 /* If there was no sliding: | |
1522 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && | |
1523 * more == window_size - lookahead - strstart | |
1524 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) | |
1525 * => more >= window_size - 2*WSIZE + 2 | |
1526 * In the BIG_MEM or MMAP case (not yet supported), | |
1527 * window_size == input_size + MIN_LOOKAHEAD && | |
1528 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. | |
1529 * Otherwise, window_size == 2*WSIZE so more >= 2. | |
1530 * If there was sliding, more >= WSIZE. So in all cases, more >= 2. | |
1531 */ | |
1532 Assert(more >= 2, "more < 2"); | |
1533 | |
1534 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); | |
1535 s->lookahead += n; | |
1536 | |
1537 /* Initialize the hash value now that we have some input: */ | |
1538 if (s->lookahead + s->insert >= MIN_MATCH) { | |
1539 uInt str = s->strstart - s->insert; | |
1540 s->ins_h = s->window[str]; | |
1541 UPDATE_HASH(s, s->ins_h, s->window[str + 1]); | |
1542 #if MIN_MATCH != 3 | |
1543 Call UPDATE_HASH() MIN_MATCH-3 more times | |
1544 #endif | |
1545 while (s->insert) { | |
1546 UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); | |
1547 #ifndef FASTEST | |
1548 s->prev[str & s->w_mask] = s->head[s->ins_h]; | |
1549 #endif | |
1550 s->head[s->ins_h] = (Pos)str; | |
1551 str++; | |
1552 s->insert--; | |
1553 if (s->lookahead + s->insert < MIN_MATCH) | |
1554 break; | |
1555 } | |
1556 } | |
1557 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, | |
1558 * but this is not important since only literal bytes will be emitted. | |
1559 */ | |
1560 | |
1561 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); | |
1562 | |
1563 /* If the WIN_INIT bytes after the end of the current data have never been | |
1564 * written, then zero those bytes in order to avoid memory check reports of | |
1565 * the use of uninitialized (or uninitialised as Julian writes) bytes by | |
1566 * the longest match routines. Update the high water mark for the next | |
1567 * time through here. WIN_INIT is set to MAX_MATCH since the longest match | |
1568 * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. | |
1569 */ | |
1570 if (s->high_water < s->window_size) { | |
1571 ulg curr = s->strstart + (ulg)(s->lookahead); | |
1572 ulg init; | |
1573 | |
1574 if (s->high_water < curr) { | |
1575 /* Previous high water mark below current data -- zero WIN_INIT | |
1576 * bytes or up to end of window, whichever is less. | |
1577 */ | |
1578 init = s->window_size - curr; | |
1579 if (init > WIN_INIT) | |
1580 init = WIN_INIT; | |
1581 zmemzero(s->window + curr, (unsigned)init); | |
1582 s->high_water = curr + init; | |
1583 } | |
1584 else if (s->high_water < (ulg)curr + WIN_INIT) { | |
1585 /* High water mark at or above current data, but below current data | |
1586 * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up | |
1587 * to end of window, whichever is less. | |
1588 */ | |
1589 init = (ulg)curr + WIN_INIT - s->high_water; | |
1590 if (init > s->window_size - s->high_water) | |
1591 init = s->window_size - s->high_water; | |
1592 zmemzero(s->window + s->high_water, (unsigned)init); | |
1593 s->high_water += init; | |
1594 } | |
1595 } | |
1596 | |
1597 Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, | |
1598 "not enough room for search"); | |
1599 } | |
1600 | |
1601 /* =========================================================================== | |
1602 * Flush the current block, with given end-of-file flag. | |
1603 * IN assertion: strstart is set to the end of the current match. | |
1604 */ | |
1605 #define FLUSH_BLOCK_ONLY(s, last) { \ | |
1606 _tr_flush_block(s, (s->block_start >= 0L ? \ | |
1607 (charf *)&s->window[(unsigned)s->block_start] : \ | |
1608 (charf *)Z_NULL), \ | |
1609 (ulg)((long)s->strstart - s->block_start), \ | |
1610 (last)); \ | |
1611 s->block_start = s->strstart; \ | |
1612 flush_pending(s->strm); \ | |
1613 Tracev((stderr,"[FLUSH]")); \ | |
1614 } | |
1615 | |
1616 /* Same but force premature exit if necessary. */ | |
1617 #define FLUSH_BLOCK(s, last) { \ | |
1618 FLUSH_BLOCK_ONLY(s, last); \ | |
1619 if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ | |
1620 } | |
1621 | |
1622 /* Maximum stored block length in deflate format (not including header). */ | |
1623 #define MAX_STORED 65535 | |
1624 | |
1625 /* Minimum of a and b. */ | |
1626 #define MIN(a, b) ((a) > (b) ? (b) : (a)) | |
1627 | |
1628 /* =========================================================================== | |
1629 * Copy without compression as much as possible from the input stream, return | |
1630 * the current block state. | |
1631 * | |
1632 * In case deflateParams() is used to later switch to a non-zero compression | |
1633 * level, s->matches (otherwise unused when storing) keeps track of the number | |
1634 * of hash table slides to perform. If s->matches is 1, then one hash table | |
1635 * slide will be done when switching. If s->matches is 2, the maximum value | |
1636 * allowed here, then the hash table will be cleared, since two or more slides | |
1637 * is the same as a clear. | |
1638 * | |
1639 * deflate_stored() is written to minimize the number of times an input byte is | |
1640 * copied. It is most efficient with large input and output buffers, which | |
1641 * maximizes the opportunites to have a single copy from next_in to next_out. | |
1642 */ | |
1643 local block_state deflate_stored(s, flush) | |
1644 deflate_state *s; | |
1645 int flush; | |
1646 { | |
1647 /* Smallest worthy block size when not flushing or finishing. By default | |
1648 * this is 32K. This can be as small as 507 bytes for memLevel == 1. For | |
1649 * large input and output buffers, the stored block size will be larger. | |
1650 */ | |
1651 unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size); | |
1652 | |
1653 /* Copy as many min_block or larger stored blocks directly to next_out as | |
1654 * possible. If flushing, copy the remaining available input to next_out as | |
1655 * stored blocks, if there is enough space. | |
1656 */ | |
1657 unsigned len, left, have, last = 0; | |
1658 unsigned used = s->strm->avail_in; | |
1659 do { | |
1660 /* Set len to the maximum size block that we can copy directly with the | |
1661 * available input data and output space. Set left to how much of that | |
1662 * would be copied from what's left in the window. | |
1663 */ | |
1664 len = MAX_STORED; /* maximum deflate stored block length */ | |
1665 have = (s->bi_valid + 42) >> 3; /* number of header bytes */ | |
1666 if (s->strm->avail_out < have) /* need room for header */ | |
1667 break; | |
1668 /* maximum stored block length that will fit in avail_out: */ | |
1669 have = s->strm->avail_out - have; | |
1670 left = s->strstart - s->block_start; /* bytes left in window */ | |
1671 if (len > (ulg)left + s->strm->avail_in) | |
1672 len = left + s->strm->avail_in; /* limit len to the input */ | |
1673 if (len > have) | |
1674 len = have; /* limit len to the output */ | |
1675 | |
1676 /* If the stored block would be less than min_block in length, or if | |
1677 * unable to copy all of the available input when flushing, then try | |
1678 * copying to the window and the pending buffer instead. Also don't | |
1679 * write an empty block when flushing -- deflate() does that. | |
1680 */ | |
1681 if (len < min_block && ((len == 0 && flush != Z_FINISH) || | |
1682 flush == Z_NO_FLUSH || | |
1683 len != left + s->strm->avail_in)) | |
1684 break; | |
1685 | |
1686 /* Make a dummy stored block in pending to get the header bytes, | |
1687 * including any pending bits. This also updates the debugging counts. | |
1688 */ | |
1689 last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0; | |
1690 _tr_stored_block(s, (char *)0, 0L, last); | |
1691 | |
1692 /* Replace the lengths in the dummy stored block with len. */ | |
1693 s->pending_buf[s->pending - 4] = len; | |
1694 s->pending_buf[s->pending - 3] = len >> 8; | |
1695 s->pending_buf[s->pending - 2] = ~len; | |
1696 s->pending_buf[s->pending - 1] = ~len >> 8; | |
1697 | |
1698 /* Write the stored block header bytes. */ | |
1699 flush_pending(s->strm); | |
1700 | |
1701 #ifdef ZLIB_DEBUG | |
1702 /* Update debugging counts for the data about to be copied. */ | |
1703 s->compressed_len += len << 3; | |
1704 s->bits_sent += len << 3; | |
1705 #endif | |
1706 | |
1707 /* Copy uncompressed bytes from the window to next_out. */ | |
1708 if (left) { | |
1709 if (left > len) | |
1710 left = len; | |
1711 zmemcpy(s->strm->next_out, s->window + s->block_start, left); | |
1712 s->strm->next_out += left; | |
1713 s->strm->avail_out -= left; | |
1714 s->strm->total_out += left; | |
1715 s->block_start += left; | |
1716 len -= left; | |
1717 } | |
1718 | |
1719 /* Copy uncompressed bytes directly from next_in to next_out, updating | |
1720 * the check value. | |
1721 */ | |
1722 if (len) { | |
1723 read_buf(s->strm, s->strm->next_out, len); | |
1724 s->strm->next_out += len; | |
1725 s->strm->avail_out -= len; | |
1726 s->strm->total_out += len; | |
1727 } | |
1728 } while (last == 0); | |
1729 | |
1730 /* Update the sliding window with the last s->w_size bytes of the copied | |
1731 * data, or append all of the copied data to the existing window if less | |
1732 * than s->w_size bytes were copied. Also update the number of bytes to | |
1733 * insert in the hash tables, in the event that deflateParams() switches to | |
1734 * a non-zero compression level. | |
1735 */ | |
1736 used -= s->strm->avail_in; /* number of input bytes directly copied */ | |
1737 if (used) { | |
1738 /* If any input was used, then no unused input remains in the window, | |
1739 * therefore s->block_start == s->strstart. | |
1740 */ | |
1741 if (used >= s->w_size) { /* supplant the previous history */ | |
1742 s->matches = 2; /* clear hash */ | |
1743 zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); | |
1744 s->strstart = s->w_size; | |
1745 } | |
1746 else { | |
1747 if (s->window_size - s->strstart <= used) { | |
1748 /* Slide the window down. */ | |
1749 s->strstart -= s->w_size; | |
1750 zmemcpy(s->window, s->window + s->w_size, s->strstart); | |
1751 if (s->matches < 2) | |
1752 s->matches++; /* add a pending slide_hash() */ | |
1753 } | |
1754 zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); | |
1755 s->strstart += used; | |
1756 } | |
1757 s->block_start = s->strstart; | |
1758 s->insert += MIN(used, s->w_size - s->insert); | |
1759 } | |
1760 if (s->high_water < s->strstart) | |
1761 s->high_water = s->strstart; | |
1762 | |
1763 /* If the last block was written to next_out, then done. */ | |
1764 if (last) | |
1765 return finish_done; | |
1766 | |
1767 /* If flushing and all input has been consumed, then done. */ | |
1768 if (flush != Z_NO_FLUSH && flush != Z_FINISH && | |
1769 s->strm->avail_in == 0 && (long)s->strstart == s->block_start) | |
1770 return block_done; | |
1771 | |
1772 /* Fill the window with any remaining input. */ | |
1773 have = s->window_size - s->strstart - 1; | |
1774 if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { | |
1775 /* Slide the window down. */ | |
1776 s->block_start -= s->w_size; | |
1777 s->strstart -= s->w_size; | |
1778 zmemcpy(s->window, s->window + s->w_size, s->strstart); | |
1779 if (s->matches < 2) | |
1780 s->matches++; /* add a pending slide_hash() */ | |
1781 have += s->w_size; /* more space now */ | |
1782 } | |
1783 if (have > s->strm->avail_in) | |
1784 have = s->strm->avail_in; | |
1785 if (have) { | |
1786 read_buf(s->strm, s->window + s->strstart, have); | |
1787 s->strstart += have; | |
1788 } | |
1789 if (s->high_water < s->strstart) | |
1790 s->high_water = s->strstart; | |
1791 | |
1792 /* There was not enough avail_out to write a complete worthy or flushed | |
1793 * stored block to next_out. Write a stored block to pending instead, if we | |
1794 * have enough input for a worthy block, or if flushing and there is enough | |
1795 * room for the remaining input as a stored block in the pending buffer. | |
1796 */ | |
1797 have = (s->bi_valid + 42) >> 3; /* number of header bytes */ | |
1798 /* maximum stored block length that will fit in pending: */ | |
1799 have = MIN(s->pending_buf_size - have, MAX_STORED); | |
1800 min_block = MIN(have, s->w_size); | |
1801 left = s->strstart - s->block_start; | |
1802 if (left >= min_block || | |
1803 ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH && | |
1804 s->strm->avail_in == 0 && left <= have)) { | |
1805 len = MIN(left, have); | |
1806 last = flush == Z_FINISH && s->strm->avail_in == 0 && | |
1807 len == left ? 1 : 0; | |
1808 _tr_stored_block(s, (charf *)s->window + s->block_start, len, last); | |
1809 s->block_start += len; | |
1810 flush_pending(s->strm); | |
1811 } | |
1812 | |
1813 /* We've done all we can with the available input and output. */ | |
1814 return last ? finish_started : need_more; | |
1815 } | |
1816 | |
1817 /* =========================================================================== | |
1818 * Compress as much as possible from the input stream, return the current | |
1819 * block state. | |
1820 * This function does not perform lazy evaluation of matches and inserts | |
1821 * new strings in the dictionary only for unmatched strings or for short | |
1822 * matches. It is used only for the fast compression options. | |
1823 */ | |
1824 local block_state deflate_fast(s, flush) | |
1825 deflate_state *s; | |
1826 int flush; | |
1827 { | |
1828 IPos hash_head; /* head of the hash chain */ | |
1829 int bflush; /* set if current block must be flushed */ | |
1830 | |
1831 for (;;) { | |
1832 /* Make sure that we always have enough lookahead, except | |
1833 * at the end of the input file. We need MAX_MATCH bytes | |
1834 * for the next match, plus MIN_MATCH bytes to insert the | |
1835 * string following the next match. | |
1836 */ | |
1837 if (s->lookahead < MIN_LOOKAHEAD) { | |
1838 fill_window(s); | |
1839 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1840 return need_more; | |
1841 } | |
1842 if (s->lookahead == 0) break; /* flush the current block */ | |
1843 } | |
1844 | |
1845 /* Insert the string window[strstart .. strstart+2] in the | |
1846 * dictionary, and set hash_head to the head of the hash chain: | |
1847 */ | |
1848 hash_head = NIL; | |
1849 if (s->lookahead >= MIN_MATCH) { | |
1850 INSERT_STRING(s, s->strstart, hash_head); | |
1851 } | |
1852 | |
1853 /* Find the longest match, discarding those <= prev_length. | |
1854 * At this point we have always match_length < MIN_MATCH | |
1855 */ | |
1856 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { | |
1857 /* To simplify the code, we prevent matches with the string | |
1858 * of window index 0 (in particular we have to avoid a match | |
1859 * of the string with itself at the start of the input file). | |
1860 */ | |
1861 s->match_length = longest_match (s, hash_head); | |
1862 /* longest_match() sets match_start */ | |
1863 } | |
1864 if (s->match_length >= MIN_MATCH) { | |
1865 check_match(s, s->strstart, s->match_start, s->match_length); | |
1866 | |
1867 _tr_tally_dist(s, s->strstart - s->match_start, | |
1868 s->match_length - MIN_MATCH, bflush); | |
1869 | |
1870 s->lookahead -= s->match_length; | |
1871 | |
1872 /* Insert new strings in the hash table only if the match length | |
1873 * is not too large. This saves time but degrades compression. | |
1874 */ | |
1875 #ifndef FASTEST | |
1876 if (s->match_length <= s->max_insert_length && | |
1877 s->lookahead >= MIN_MATCH) { | |
1878 s->match_length--; /* string at strstart already in table */ | |
1879 do { | |
1880 s->strstart++; | |
1881 INSERT_STRING(s, s->strstart, hash_head); | |
1882 /* strstart never exceeds WSIZE-MAX_MATCH, so there are | |
1883 * always MIN_MATCH bytes ahead. | |
1884 */ | |
1885 } while (--s->match_length != 0); | |
1886 s->strstart++; | |
1887 } else | |
1888 #endif | |
1889 { | |
1890 s->strstart += s->match_length; | |
1891 s->match_length = 0; | |
1892 s->ins_h = s->window[s->strstart]; | |
1893 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
1894 #if MIN_MATCH != 3 | |
1895 Call UPDATE_HASH() MIN_MATCH-3 more times | |
1896 #endif | |
1897 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not | |
1898 * matter since it will be recomputed at next deflate call. | |
1899 */ | |
1900 } | |
1901 } else { | |
1902 /* No match, output a literal byte */ | |
1903 Tracevv((stderr,"%c", s->window[s->strstart])); | |
1904 _tr_tally_lit (s, s->window[s->strstart], bflush); | |
1905 s->lookahead--; | |
1906 s->strstart++; | |
1907 } | |
1908 if (bflush) FLUSH_BLOCK(s, 0); | |
1909 } | |
1910 s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; | |
1911 if (flush == Z_FINISH) { | |
1912 FLUSH_BLOCK(s, 1); | |
1913 return finish_done; | |
1914 } | |
1915 if (s->last_lit) | |
1916 FLUSH_BLOCK(s, 0); | |
1917 return block_done; | |
1918 } | |
1919 | |
1920 #ifndef FASTEST | |
1921 /* =========================================================================== | |
1922 * Same as above, but achieves better compression. We use a lazy | |
1923 * evaluation for matches: a match is finally adopted only if there is | |
1924 * no better match at the next window position. | |
1925 */ | |
1926 local block_state deflate_slow(s, flush) | |
1927 deflate_state *s; | |
1928 int flush; | |
1929 { | |
1930 IPos hash_head; /* head of hash chain */ | |
1931 int bflush; /* set if current block must be flushed */ | |
1932 | |
1933 /* Process the input block. */ | |
1934 for (;;) { | |
1935 /* Make sure that we always have enough lookahead, except | |
1936 * at the end of the input file. We need MAX_MATCH bytes | |
1937 * for the next match, plus MIN_MATCH bytes to insert the | |
1938 * string following the next match. | |
1939 */ | |
1940 if (s->lookahead < MIN_LOOKAHEAD) { | |
1941 fill_window(s); | |
1942 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1943 return need_more; | |
1944 } | |
1945 if (s->lookahead == 0) break; /* flush the current block */ | |
1946 } | |
1947 | |
1948 /* Insert the string window[strstart .. strstart+2] in the | |
1949 * dictionary, and set hash_head to the head of the hash chain: | |
1950 */ | |
1951 hash_head = NIL; | |
1952 if (s->lookahead >= MIN_MATCH) { | |
1953 INSERT_STRING(s, s->strstart, hash_head); | |
1954 } | |
1955 | |
1956 /* Find the longest match, discarding those <= prev_length. | |
1957 */ | |
1958 s->prev_length = s->match_length, s->prev_match = s->match_start; | |
1959 s->match_length = MIN_MATCH-1; | |
1960 | |
1961 if (hash_head != NIL && s->prev_length < s->max_lazy_match && | |
1962 s->strstart - hash_head <= MAX_DIST(s)) { | |
1963 /* To simplify the code, we prevent matches with the string | |
1964 * of window index 0 (in particular we have to avoid a match | |
1965 * of the string with itself at the start of the input file). | |
1966 */ | |
1967 s->match_length = longest_match (s, hash_head); | |
1968 /* longest_match() sets match_start */ | |
1969 | |
1970 if (s->match_length <= 5 && (s->strategy == Z_FILTERED | |
1971 #if TOO_FAR <= 32767 | |
1972 || (s->match_length == MIN_MATCH && | |
1973 s->strstart - s->match_start > TOO_FAR) | |
1974 #endif | |
1975 )) { | |
1976 | |
1977 /* If prev_match is also MIN_MATCH, match_start is garbage | |
1978 * but we will ignore the current match anyway. | |
1979 */ | |
1980 s->match_length = MIN_MATCH-1; | |
1981 } | |
1982 } | |
1983 /* If there was a match at the previous step and the current | |
1984 * match is not better, output the previous match: | |
1985 */ | |
1986 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { | |
1987 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; | |
1988 /* Do not insert strings in hash table beyond this. */ | |
1989 | |
1990 check_match(s, s->strstart-1, s->prev_match, s->prev_length); | |
1991 | |
1992 _tr_tally_dist(s, s->strstart -1 - s->prev_match, | |
1993 s->prev_length - MIN_MATCH, bflush); | |
1994 | |
1995 /* Insert in hash table all strings up to the end of the match. | |
1996 * strstart-1 and strstart are already inserted. If there is not | |
1997 * enough lookahead, the last two strings are not inserted in | |
1998 * the hash table. | |
1999 */ | |
2000 s->lookahead -= s->prev_length-1; | |
2001 s->prev_length -= 2; | |
2002 do { | |
2003 if (++s->strstart <= max_insert) { | |
2004 INSERT_STRING(s, s->strstart, hash_head); | |
2005 } | |
2006 } while (--s->prev_length != 0); | |
2007 s->match_available = 0; | |
2008 s->match_length = MIN_MATCH-1; | |
2009 s->strstart++; | |
2010 | |
2011 if (bflush) FLUSH_BLOCK(s, 0); | |
2012 | |
2013 } else if (s->match_available) { | |
2014 /* If there was no match at the previous position, output a | |
2015 * single literal. If there was a match but the current match | |
2016 * is longer, truncate the previous match to a single literal. | |
2017 */ | |
2018 Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
2019 _tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
2020 if (bflush) { | |
2021 FLUSH_BLOCK_ONLY(s, 0); | |
2022 } | |
2023 s->strstart++; | |
2024 s->lookahead--; | |
2025 if (s->strm->avail_out == 0) return need_more; | |
2026 } else { | |
2027 /* There is no previous match to compare with, wait for | |
2028 * the next step to decide. | |
2029 */ | |
2030 s->match_available = 1; | |
2031 s->strstart++; | |
2032 s->lookahead--; | |
2033 } | |
2034 } | |
2035 Assert (flush != Z_NO_FLUSH, "no flush?"); | |
2036 if (s->match_available) { | |
2037 Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
2038 _tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
2039 s->match_available = 0; | |
2040 } | |
2041 s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; | |
2042 if (flush == Z_FINISH) { | |
2043 FLUSH_BLOCK(s, 1); | |
2044 return finish_done; | |
2045 } | |
2046 if (s->last_lit) | |
2047 FLUSH_BLOCK(s, 0); | |
2048 return block_done; | |
2049 } | |
2050 #endif /* FASTEST */ | |
2051 | |
2052 /* =========================================================================== | |
2053 * For Z_RLE, simply look for runs of bytes, generate matches only of distance | |
2054 * one. Do not maintain a hash table. (It will be regenerated if this run of | |
2055 * deflate switches away from Z_RLE.) | |
2056 */ | |
2057 local block_state deflate_rle(s, flush) | |
2058 deflate_state *s; | |
2059 int flush; | |
2060 { | |
2061 int bflush; /* set if current block must be flushed */ | |
2062 uInt prev; /* byte at distance one to match */ | |
2063 Bytef *scan, *strend; /* scan goes up to strend for length of run */ | |
2064 | |
2065 for (;;) { | |
2066 /* Make sure that we always have enough lookahead, except | |
2067 * at the end of the input file. We need MAX_MATCH bytes | |
2068 * for the longest run, plus one for the unrolled loop. | |
2069 */ | |
2070 if (s->lookahead <= MAX_MATCH) { | |
2071 fill_window(s); | |
2072 if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { | |
2073 return need_more; | |
2074 } | |
2075 if (s->lookahead == 0) break; /* flush the current block */ | |
2076 } | |
2077 | |
2078 /* See how many times the previous byte repeats */ | |
2079 s->match_length = 0; | |
2080 if (s->lookahead >= MIN_MATCH && s->strstart > 0) { | |
2081 scan = s->window + s->strstart - 1; | |
2082 prev = *scan; | |
2083 if (prev == *++scan && prev == *++scan && prev == *++scan) { | |
2084 strend = s->window + s->strstart + MAX_MATCH; | |
2085 do { | |
2086 } while (prev == *++scan && prev == *++scan && | |
2087 prev == *++scan && prev == *++scan && | |
2088 prev == *++scan && prev == *++scan && | |
2089 prev == *++scan && prev == *++scan && | |
2090 scan < strend); | |
2091 s->match_length = MAX_MATCH - (uInt)(strend - scan); | |
2092 if (s->match_length > s->lookahead) | |
2093 s->match_length = s->lookahead; | |
2094 } | |
2095 Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan"); | |
2096 } | |
2097 | |
2098 /* Emit match if have run of MIN_MATCH or longer, else emit literal */ | |
2099 if (s->match_length >= MIN_MATCH) { | |
2100 check_match(s, s->strstart, s->strstart - 1, s->match_length); | |
2101 | |
2102 _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); | |
2103 | |
2104 s->lookahead -= s->match_length; | |
2105 s->strstart += s->match_length; | |
2106 s->match_length = 0; | |
2107 } else { | |
2108 /* No match, output a literal byte */ | |
2109 Tracevv((stderr,"%c", s->window[s->strstart])); | |
2110 _tr_tally_lit (s, s->window[s->strstart], bflush); | |
2111 s->lookahead--; | |
2112 s->strstart++; | |
2113 } | |
2114 if (bflush) FLUSH_BLOCK(s, 0); | |
2115 } | |
2116 s->insert = 0; | |
2117 if (flush == Z_FINISH) { | |
2118 FLUSH_BLOCK(s, 1); | |
2119 return finish_done; | |
2120 } | |
2121 if (s->last_lit) | |
2122 FLUSH_BLOCK(s, 0); | |
2123 return block_done; | |
2124 } | |
2125 | |
2126 /* =========================================================================== | |
2127 * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. | |
2128 * (It will be regenerated if this run of deflate switches away from Huffman.) | |
2129 */ | |
2130 local block_state deflate_huff(s, flush) | |
2131 deflate_state *s; | |
2132 int flush; | |
2133 { | |
2134 int bflush; /* set if current block must be flushed */ | |
2135 | |
2136 for (;;) { | |
2137 /* Make sure that we have a literal to write. */ | |
2138 if (s->lookahead == 0) { | |
2139 fill_window(s); | |
2140 if (s->lookahead == 0) { | |
2141 if (flush == Z_NO_FLUSH) | |
2142 return need_more; | |
2143 break; /* flush the current block */ | |
2144 } | |
2145 } | |
2146 | |
2147 /* Output a literal byte */ | |
2148 s->match_length = 0; | |
2149 Tracevv((stderr,"%c", s->window[s->strstart])); | |
2150 _tr_tally_lit (s, s->window[s->strstart], bflush); | |
2151 s->lookahead--; | |
2152 s->strstart++; | |
2153 if (bflush) FLUSH_BLOCK(s, 0); | |
2154 } | |
2155 s->insert = 0; | |
2156 if (flush == Z_FINISH) { | |
2157 FLUSH_BLOCK(s, 1); | |
2158 return finish_done; | |
2159 } | |
2160 if (s->last_lit) | |
2161 FLUSH_BLOCK(s, 0); | |
2162 return block_done; | |
2163 } |