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author | Maurus Cuelenaere <mcuelenaere@gmail.com> | 2008-07-11 15:50:46 +0000 |
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committer | Maurus Cuelenaere <mcuelenaere@gmail.com> | 2008-07-11 15:50:46 +0000 |
commit | 14c7f45cdae826f88dc539c8c38dd95caf305731 (patch) | |
tree | 832da054b7cfb2dc6fd63339af736625f31d21aa /utils/zenutils/libraries/zlib123/zlib/deflate.c | |
parent | 7c84ede3781c27db73403bd6302f320c76a58c8c (diff) | |
download | rockbox-14c7f45cdae826f88dc539c8c38dd95caf305731.tar.gz rockbox-14c7f45cdae826f88dc539c8c38dd95caf305731.zip |
Add zook's ZenUtils to SVN
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18010 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'utils/zenutils/libraries/zlib123/zlib/deflate.c')
-rwxr-xr-x | utils/zenutils/libraries/zlib123/zlib/deflate.c | 1736 |
1 files changed, 1736 insertions, 0 deletions
diff --git a/utils/zenutils/libraries/zlib123/zlib/deflate.c b/utils/zenutils/libraries/zlib123/zlib/deflate.c new file mode 100755 index 0000000000..529f716b7a --- /dev/null +++ b/utils/zenutils/libraries/zlib123/zlib/deflate.c | |||
@@ -0,0 +1,1736 @@ | |||
1 | /* deflate.c -- compress data using the deflation algorithm | ||
2 | * Copyright (C) 1995-2005 Jean-loup Gailly. | ||
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 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; | ||
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 void lm_init OF((deflate_state *s)); | ||
83 | local void putShortMSB OF((deflate_state *s, uInt b)); | ||
84 | local void flush_pending OF((z_streamp strm)); | ||
85 | local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); | ||
86 | #ifndef FASTEST | ||
87 | #ifdef ASMV | ||
88 | void match_init OF((void)); /* asm code initialization */ | ||
89 | uInt longest_match OF((deflate_state *s, IPos cur_match)); | ||
90 | #else | ||
91 | local uInt longest_match OF((deflate_state *s, IPos cur_match)); | ||
92 | #endif | ||
93 | #endif | ||
94 | local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); | ||
95 | |||
96 | #ifdef DEBUG | ||
97 | local void check_match OF((deflate_state *s, IPos start, IPos match, | ||
98 | int length)); | ||
99 | #endif | ||
100 | |||
101 | /* =========================================================================== | ||
102 | * Local data | ||
103 | */ | ||
104 | |||
105 | #define NIL 0 | ||
106 | /* Tail of hash chains */ | ||
107 | |||
108 | #ifndef TOO_FAR | ||
109 | # define TOO_FAR 4096 | ||
110 | #endif | ||
111 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ | ||
112 | |||
113 | #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) | ||
114 | /* Minimum amount of lookahead, except at the end of the input file. | ||
115 | * See deflate.c for comments about the MIN_MATCH+1. | ||
116 | */ | ||
117 | |||
118 | /* Values for max_lazy_match, good_match and max_chain_length, depending on | ||
119 | * the desired pack level (0..9). The values given below have been tuned to | ||
120 | * exclude worst case performance for pathological files. Better values may be | ||
121 | * found for specific files. | ||
122 | */ | ||
123 | typedef struct config_s { | ||
124 | ush good_length; /* reduce lazy search above this match length */ | ||
125 | ush max_lazy; /* do not perform lazy search above this match length */ | ||
126 | ush nice_length; /* quit search above this match length */ | ||
127 | ush max_chain; | ||
128 | compress_func func; | ||
129 | } config; | ||
130 | |||
131 | #ifdef FASTEST | ||
132 | local const config configuration_table[2] = { | ||
133 | /* good lazy nice chain */ | ||
134 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | ||
135 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ | ||
136 | #else | ||
137 | local const config configuration_table[10] = { | ||
138 | /* good lazy nice chain */ | ||
139 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | ||
140 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ | ||
141 | /* 2 */ {4, 5, 16, 8, deflate_fast}, | ||
142 | /* 3 */ {4, 6, 32, 32, deflate_fast}, | ||
143 | |||
144 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ | ||
145 | /* 5 */ {8, 16, 32, 32, deflate_slow}, | ||
146 | /* 6 */ {8, 16, 128, 128, deflate_slow}, | ||
147 | /* 7 */ {8, 32, 128, 256, deflate_slow}, | ||
148 | /* 8 */ {32, 128, 258, 1024, deflate_slow}, | ||
149 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ | ||
150 | #endif | ||
151 | |||
152 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 | ||
153 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different | ||
154 | * meaning. | ||
155 | */ | ||
156 | |||
157 | #define EQUAL 0 | ||
158 | /* result of memcmp for equal strings */ | ||
159 | |||
160 | #ifndef NO_DUMMY_DECL | ||
161 | struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ | ||
162 | #endif | ||
163 | |||
164 | /* =========================================================================== | ||
165 | * Update a hash value with the given input byte | ||
166 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive | ||
167 | * input characters, so that a running hash key can be computed from the | ||
168 | * previous key instead of complete recalculation each time. | ||
169 | */ | ||
170 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) | ||
171 | |||
172 | |||
173 | /* =========================================================================== | ||
174 | * Insert string str in the dictionary and set match_head to the previous head | ||
175 | * of the hash chain (the most recent string with same hash key). Return | ||
176 | * the previous length of the hash chain. | ||
177 | * If this file is compiled with -DFASTEST, the compression level is forced | ||
178 | * to 1, and no hash chains are maintained. | ||
179 | * IN assertion: all calls to to INSERT_STRING are made with consecutive | ||
180 | * input characters and the first MIN_MATCH bytes of str are valid | ||
181 | * (except for the last MIN_MATCH-1 bytes of the input file). | ||
182 | */ | ||
183 | #ifdef FASTEST | ||
184 | #define INSERT_STRING(s, str, match_head) \ | ||
185 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | ||
186 | match_head = s->head[s->ins_h], \ | ||
187 | s->head[s->ins_h] = (Pos)(str)) | ||
188 | #else | ||
189 | #define INSERT_STRING(s, str, match_head) \ | ||
190 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | ||
191 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ | ||
192 | s->head[s->ins_h] = (Pos)(str)) | ||
193 | #endif | ||
194 | |||
195 | /* =========================================================================== | ||
196 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems). | ||
197 | * prev[] will be initialized on the fly. | ||
198 | */ | ||
199 | #define CLEAR_HASH(s) \ | ||
200 | s->head[s->hash_size-1] = NIL; \ | ||
201 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); | ||
202 | |||
203 | /* ========================================================================= */ | ||
204 | int ZEXPORT deflateInit_(strm, level, version, stream_size) | ||
205 | z_streamp strm; | ||
206 | int level; | ||
207 | const char *version; | ||
208 | int stream_size; | ||
209 | { | ||
210 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, | ||
211 | Z_DEFAULT_STRATEGY, version, stream_size); | ||
212 | /* To do: ignore strm->next_in if we use it as window */ | ||
213 | } | ||
214 | |||
215 | /* ========================================================================= */ | ||
216 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, | ||
217 | version, stream_size) | ||
218 | z_streamp strm; | ||
219 | int level; | ||
220 | int method; | ||
221 | int windowBits; | ||
222 | int memLevel; | ||
223 | int strategy; | ||
224 | const char *version; | ||
225 | int stream_size; | ||
226 | { | ||
227 | deflate_state *s; | ||
228 | int wrap = 1; | ||
229 | static const char my_version[] = ZLIB_VERSION; | ||
230 | |||
231 | ushf *overlay; | ||
232 | /* We overlay pending_buf and d_buf+l_buf. This works since the average | ||
233 | * output size for (length,distance) codes is <= 24 bits. | ||
234 | */ | ||
235 | |||
236 | if (version == Z_NULL || version[0] != my_version[0] || | ||
237 | stream_size != sizeof(z_stream)) { | ||
238 | return Z_VERSION_ERROR; | ||
239 | } | ||
240 | if (strm == Z_NULL) return Z_STREAM_ERROR; | ||
241 | |||
242 | strm->msg = Z_NULL; | ||
243 | if (strm->zalloc == (alloc_func)0) { | ||
244 | strm->zalloc = zcalloc; | ||
245 | strm->opaque = (voidpf)0; | ||
246 | } | ||
247 | if (strm->zfree == (free_func)0) strm->zfree = zcfree; | ||
248 | |||
249 | #ifdef FASTEST | ||
250 | if (level != 0) level = 1; | ||
251 | #else | ||
252 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | ||
253 | #endif | ||
254 | |||
255 | if (windowBits < 0) { /* suppress zlib wrapper */ | ||
256 | wrap = 0; | ||
257 | windowBits = -windowBits; | ||
258 | } | ||
259 | #ifdef GZIP | ||
260 | else if (windowBits > 15) { | ||
261 | wrap = 2; /* write gzip wrapper instead */ | ||
262 | windowBits -= 16; | ||
263 | } | ||
264 | #endif | ||
265 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || | ||
266 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || | ||
267 | strategy < 0 || strategy > Z_FIXED) { | ||
268 | return Z_STREAM_ERROR; | ||
269 | } | ||
270 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ | ||
271 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); | ||
272 | if (s == Z_NULL) return Z_MEM_ERROR; | ||
273 | strm->state = (struct internal_state FAR *)s; | ||
274 | s->strm = strm; | ||
275 | |||
276 | s->wrap = wrap; | ||
277 | s->gzhead = Z_NULL; | ||
278 | s->w_bits = windowBits; | ||
279 | s->w_size = 1 << s->w_bits; | ||
280 | s->w_mask = s->w_size - 1; | ||
281 | |||
282 | s->hash_bits = memLevel + 7; | ||
283 | s->hash_size = 1 << s->hash_bits; | ||
284 | s->hash_mask = s->hash_size - 1; | ||
285 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); | ||
286 | |||
287 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); | ||
288 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); | ||
289 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); | ||
290 | |||
291 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ | ||
292 | |||
293 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); | ||
294 | s->pending_buf = (uchf *) overlay; | ||
295 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); | ||
296 | |||
297 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || | ||
298 | s->pending_buf == Z_NULL) { | ||
299 | s->status = FINISH_STATE; | ||
300 | strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); | ||
301 | deflateEnd (strm); | ||
302 | return Z_MEM_ERROR; | ||
303 | } | ||
304 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush); | ||
305 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; | ||
306 | |||
307 | s->level = level; | ||
308 | s->strategy = strategy; | ||
309 | s->method = (Byte)method; | ||
310 | |||
311 | return deflateReset(strm); | ||
312 | } | ||
313 | |||
314 | /* ========================================================================= */ | ||
315 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) | ||
316 | z_streamp strm; | ||
317 | const Bytef *dictionary; | ||
318 | uInt dictLength; | ||
319 | { | ||
320 | deflate_state *s; | ||
321 | uInt length = dictLength; | ||
322 | uInt n; | ||
323 | IPos hash_head = 0; | ||
324 | |||
325 | if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || | ||
326 | strm->state->wrap == 2 || | ||
327 | (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) | ||
328 | return Z_STREAM_ERROR; | ||
329 | |||
330 | s = strm->state; | ||
331 | if (s->wrap) | ||
332 | strm->adler = adler32(strm->adler, dictionary, dictLength); | ||
333 | |||
334 | if (length < MIN_MATCH) return Z_OK; | ||
335 | if (length > MAX_DIST(s)) { | ||
336 | length = MAX_DIST(s); | ||
337 | dictionary += dictLength - length; /* use the tail of the dictionary */ | ||
338 | } | ||
339 | zmemcpy(s->window, dictionary, length); | ||
340 | s->strstart = length; | ||
341 | s->block_start = (long)length; | ||
342 | |||
343 | /* Insert all strings in the hash table (except for the last two bytes). | ||
344 | * s->lookahead stays null, so s->ins_h will be recomputed at the next | ||
345 | * call of fill_window. | ||
346 | */ | ||
347 | s->ins_h = s->window[0]; | ||
348 | UPDATE_HASH(s, s->ins_h, s->window[1]); | ||
349 | for (n = 0; n <= length - MIN_MATCH; n++) { | ||
350 | INSERT_STRING(s, n, hash_head); | ||
351 | } | ||
352 | if (hash_head) hash_head = 0; /* to make compiler happy */ | ||
353 | return Z_OK; | ||
354 | } | ||
355 | |||
356 | /* ========================================================================= */ | ||
357 | int ZEXPORT deflateReset (strm) | ||
358 | z_streamp strm; | ||
359 | { | ||
360 | deflate_state *s; | ||
361 | |||
362 | if (strm == Z_NULL || strm->state == Z_NULL || | ||
363 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { | ||
364 | return Z_STREAM_ERROR; | ||
365 | } | ||
366 | |||
367 | strm->total_in = strm->total_out = 0; | ||
368 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ | ||
369 | strm->data_type = Z_UNKNOWN; | ||
370 | |||
371 | s = (deflate_state *)strm->state; | ||
372 | s->pending = 0; | ||
373 | s->pending_out = s->pending_buf; | ||
374 | |||
375 | if (s->wrap < 0) { | ||
376 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ | ||
377 | } | ||
378 | s->status = s->wrap ? INIT_STATE : BUSY_STATE; | ||
379 | strm->adler = | ||
380 | #ifdef GZIP | ||
381 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) : | ||
382 | #endif | ||
383 | adler32(0L, Z_NULL, 0); | ||
384 | s->last_flush = Z_NO_FLUSH; | ||
385 | |||
386 | _tr_init(s); | ||
387 | lm_init(s); | ||
388 | |||
389 | return Z_OK; | ||
390 | } | ||
391 | |||
392 | /* ========================================================================= */ | ||
393 | int ZEXPORT deflateSetHeader (strm, head) | ||
394 | z_streamp strm; | ||
395 | gz_headerp head; | ||
396 | { | ||
397 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | ||
398 | if (strm->state->wrap != 2) return Z_STREAM_ERROR; | ||
399 | strm->state->gzhead = head; | ||
400 | return Z_OK; | ||
401 | } | ||
402 | |||
403 | /* ========================================================================= */ | ||
404 | int ZEXPORT deflatePrime (strm, bits, value) | ||
405 | z_streamp strm; | ||
406 | int bits; | ||
407 | int value; | ||
408 | { | ||
409 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | ||
410 | strm->state->bi_valid = bits; | ||
411 | strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); | ||
412 | return Z_OK; | ||
413 | } | ||
414 | |||
415 | /* ========================================================================= */ | ||
416 | int ZEXPORT deflateParams(strm, level, strategy) | ||
417 | z_streamp strm; | ||
418 | int level; | ||
419 | int strategy; | ||
420 | { | ||
421 | deflate_state *s; | ||
422 | compress_func func; | ||
423 | int err = Z_OK; | ||
424 | |||
425 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | ||
426 | s = strm->state; | ||
427 | |||
428 | #ifdef FASTEST | ||
429 | if (level != 0) level = 1; | ||
430 | #else | ||
431 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | ||
432 | #endif | ||
433 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { | ||
434 | return Z_STREAM_ERROR; | ||
435 | } | ||
436 | func = configuration_table[s->level].func; | ||
437 | |||
438 | if (func != configuration_table[level].func && strm->total_in != 0) { | ||
439 | /* Flush the last buffer: */ | ||
440 | err = deflate(strm, Z_PARTIAL_FLUSH); | ||
441 | } | ||
442 | if (s->level != level) { | ||
443 | s->level = level; | ||
444 | s->max_lazy_match = configuration_table[level].max_lazy; | ||
445 | s->good_match = configuration_table[level].good_length; | ||
446 | s->nice_match = configuration_table[level].nice_length; | ||
447 | s->max_chain_length = configuration_table[level].max_chain; | ||
448 | } | ||
449 | s->strategy = strategy; | ||
450 | return err; | ||
451 | } | ||
452 | |||
453 | /* ========================================================================= */ | ||
454 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) | ||
455 | z_streamp strm; | ||
456 | int good_length; | ||
457 | int max_lazy; | ||
458 | int nice_length; | ||
459 | int max_chain; | ||
460 | { | ||
461 | deflate_state *s; | ||
462 | |||
463 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | ||
464 | s = strm->state; | ||
465 | s->good_match = good_length; | ||
466 | s->max_lazy_match = max_lazy; | ||
467 | s->nice_match = nice_length; | ||
468 | s->max_chain_length = max_chain; | ||
469 | return Z_OK; | ||
470 | } | ||
471 | |||
472 | /* ========================================================================= | ||
473 | * For the default windowBits of 15 and memLevel of 8, this function returns | ||
474 | * a close to exact, as well as small, upper bound on the compressed size. | ||
475 | * They are coded as constants here for a reason--if the #define's are | ||
476 | * changed, then this function needs to be changed as well. The return | ||
477 | * value for 15 and 8 only works for those exact settings. | ||
478 | * | ||
479 | * For any setting other than those defaults for windowBits and memLevel, | ||
480 | * the value returned is a conservative worst case for the maximum expansion | ||
481 | * resulting from using fixed blocks instead of stored blocks, which deflate | ||
482 | * can emit on compressed data for some combinations of the parameters. | ||
483 | * | ||
484 | * This function could be more sophisticated to provide closer upper bounds | ||
485 | * for every combination of windowBits and memLevel, as well as wrap. | ||
486 | * But even the conservative upper bound of about 14% expansion does not | ||
487 | * seem onerous for output buffer allocation. | ||
488 | */ | ||
489 | uLong ZEXPORT deflateBound(strm, sourceLen) | ||
490 | z_streamp strm; | ||
491 | uLong sourceLen; | ||
492 | { | ||
493 | deflate_state *s; | ||
494 | uLong destLen; | ||
495 | |||
496 | /* conservative upper bound */ | ||
497 | destLen = sourceLen + | ||
498 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; | ||
499 | |||
500 | /* if can't get parameters, return conservative bound */ | ||
501 | if (strm == Z_NULL || strm->state == Z_NULL) | ||
502 | return destLen; | ||
503 | |||
504 | /* if not default parameters, return conservative bound */ | ||
505 | s = strm->state; | ||
506 | if (s->w_bits != 15 || s->hash_bits != 8 + 7) | ||
507 | return destLen; | ||
508 | |||
509 | /* default settings: return tight bound for that case */ | ||
510 | return compressBound(sourceLen); | ||
511 | } | ||
512 | |||
513 | /* ========================================================================= | ||
514 | * Put a short in the pending buffer. The 16-bit value is put in MSB order. | ||
515 | * IN assertion: the stream state is correct and there is enough room in | ||
516 | * pending_buf. | ||
517 | */ | ||
518 | local void putShortMSB (s, b) | ||
519 | deflate_state *s; | ||
520 | uInt b; | ||
521 | { | ||
522 | put_byte(s, (Byte)(b >> 8)); | ||
523 | put_byte(s, (Byte)(b & 0xff)); | ||
524 | } | ||
525 | |||
526 | /* ========================================================================= | ||
527 | * Flush as much pending output as possible. All deflate() output goes | ||
528 | * through this function so some applications may wish to modify it | ||
529 | * to avoid allocating a large strm->next_out buffer and copying into it. | ||
530 | * (See also read_buf()). | ||
531 | */ | ||
532 | local void flush_pending(strm) | ||
533 | z_streamp strm; | ||
534 | { | ||
535 | unsigned len = strm->state->pending; | ||
536 | |||
537 | if (len > strm->avail_out) len = strm->avail_out; | ||
538 | if (len == 0) return; | ||
539 | |||
540 | zmemcpy(strm->next_out, strm->state->pending_out, len); | ||
541 | strm->next_out += len; | ||
542 | strm->state->pending_out += len; | ||
543 | strm->total_out += len; | ||
544 | strm->avail_out -= len; | ||
545 | strm->state->pending -= len; | ||
546 | if (strm->state->pending == 0) { | ||
547 | strm->state->pending_out = strm->state->pending_buf; | ||
548 | } | ||
549 | } | ||
550 | |||
551 | /* ========================================================================= */ | ||
552 | int ZEXPORT deflate (strm, flush) | ||
553 | z_streamp strm; | ||
554 | int flush; | ||
555 | { | ||
556 | int old_flush; /* value of flush param for previous deflate call */ | ||
557 | deflate_state *s; | ||
558 | |||
559 | if (strm == Z_NULL || strm->state == Z_NULL || | ||
560 | flush > Z_FINISH || flush < 0) { | ||
561 | return Z_STREAM_ERROR; | ||
562 | } | ||
563 | s = strm->state; | ||
564 | |||
565 | if (strm->next_out == Z_NULL || | ||
566 | (strm->next_in == Z_NULL && strm->avail_in != 0) || | ||
567 | (s->status == FINISH_STATE && flush != Z_FINISH)) { | ||
568 | ERR_RETURN(strm, Z_STREAM_ERROR); | ||
569 | } | ||
570 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); | ||
571 | |||
572 | s->strm = strm; /* just in case */ | ||
573 | old_flush = s->last_flush; | ||
574 | s->last_flush = flush; | ||
575 | |||
576 | /* Write the header */ | ||
577 | if (s->status == INIT_STATE) { | ||
578 | #ifdef GZIP | ||
579 | if (s->wrap == 2) { | ||
580 | strm->adler = crc32(0L, Z_NULL, 0); | ||
581 | put_byte(s, 31); | ||
582 | put_byte(s, 139); | ||
583 | put_byte(s, 8); | ||
584 | if (s->gzhead == NULL) { | ||
585 | put_byte(s, 0); | ||
586 | put_byte(s, 0); | ||
587 | put_byte(s, 0); | ||
588 | put_byte(s, 0); | ||
589 | put_byte(s, 0); | ||
590 | put_byte(s, s->level == 9 ? 2 : | ||
591 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | ||
592 | 4 : 0)); | ||
593 | put_byte(s, OS_CODE); | ||
594 | s->status = BUSY_STATE; | ||
595 | } | ||
596 | else { | ||
597 | put_byte(s, (s->gzhead->text ? 1 : 0) + | ||
598 | (s->gzhead->hcrc ? 2 : 0) + | ||
599 | (s->gzhead->extra == Z_NULL ? 0 : 4) + | ||
600 | (s->gzhead->name == Z_NULL ? 0 : 8) + | ||
601 | (s->gzhead->comment == Z_NULL ? 0 : 16) | ||
602 | ); | ||
603 | put_byte(s, (Byte)(s->gzhead->time & 0xff)); | ||
604 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); | ||
605 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); | ||
606 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); | ||
607 | put_byte(s, s->level == 9 ? 2 : | ||
608 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | ||
609 | 4 : 0)); | ||
610 | put_byte(s, s->gzhead->os & 0xff); | ||
611 | if (s->gzhead->extra != NULL) { | ||
612 | put_byte(s, s->gzhead->extra_len & 0xff); | ||
613 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); | ||
614 | } | ||
615 | if (s->gzhead->hcrc) | ||
616 | strm->adler = crc32(strm->adler, s->pending_buf, | ||
617 | s->pending); | ||
618 | s->gzindex = 0; | ||
619 | s->status = EXTRA_STATE; | ||
620 | } | ||
621 | } | ||
622 | else | ||
623 | #endif | ||
624 | { | ||
625 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; | ||
626 | uInt level_flags; | ||
627 | |||
628 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) | ||
629 | level_flags = 0; | ||
630 | else if (s->level < 6) | ||
631 | level_flags = 1; | ||
632 | else if (s->level == 6) | ||
633 | level_flags = 2; | ||
634 | else | ||
635 | level_flags = 3; | ||
636 | header |= (level_flags << 6); | ||
637 | if (s->strstart != 0) header |= PRESET_DICT; | ||
638 | header += 31 - (header % 31); | ||
639 | |||
640 | s->status = BUSY_STATE; | ||
641 | putShortMSB(s, header); | ||
642 | |||
643 | /* Save the adler32 of the preset dictionary: */ | ||
644 | if (s->strstart != 0) { | ||
645 | putShortMSB(s, (uInt)(strm->adler >> 16)); | ||
646 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | ||
647 | } | ||
648 | strm->adler = adler32(0L, Z_NULL, 0); | ||
649 | } | ||
650 | } | ||
651 | #ifdef GZIP | ||
652 | if (s->status == EXTRA_STATE) { | ||
653 | if (s->gzhead->extra != NULL) { | ||
654 | uInt beg = s->pending; /* start of bytes to update crc */ | ||
655 | |||
656 | while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { | ||
657 | if (s->pending == s->pending_buf_size) { | ||
658 | if (s->gzhead->hcrc && s->pending > beg) | ||
659 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
660 | s->pending - beg); | ||
661 | flush_pending(strm); | ||
662 | beg = s->pending; | ||
663 | if (s->pending == s->pending_buf_size) | ||
664 | break; | ||
665 | } | ||
666 | put_byte(s, s->gzhead->extra[s->gzindex]); | ||
667 | s->gzindex++; | ||
668 | } | ||
669 | if (s->gzhead->hcrc && s->pending > beg) | ||
670 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
671 | s->pending - beg); | ||
672 | if (s->gzindex == s->gzhead->extra_len) { | ||
673 | s->gzindex = 0; | ||
674 | s->status = NAME_STATE; | ||
675 | } | ||
676 | } | ||
677 | else | ||
678 | s->status = NAME_STATE; | ||
679 | } | ||
680 | if (s->status == NAME_STATE) { | ||
681 | if (s->gzhead->name != NULL) { | ||
682 | uInt beg = s->pending; /* start of bytes to update crc */ | ||
683 | int val; | ||
684 | |||
685 | do { | ||
686 | if (s->pending == s->pending_buf_size) { | ||
687 | if (s->gzhead->hcrc && s->pending > beg) | ||
688 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
689 | s->pending - beg); | ||
690 | flush_pending(strm); | ||
691 | beg = s->pending; | ||
692 | if (s->pending == s->pending_buf_size) { | ||
693 | val = 1; | ||
694 | break; | ||
695 | } | ||
696 | } | ||
697 | val = s->gzhead->name[s->gzindex++]; | ||
698 | put_byte(s, val); | ||
699 | } while (val != 0); | ||
700 | if (s->gzhead->hcrc && s->pending > beg) | ||
701 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
702 | s->pending - beg); | ||
703 | if (val == 0) { | ||
704 | s->gzindex = 0; | ||
705 | s->status = COMMENT_STATE; | ||
706 | } | ||
707 | } | ||
708 | else | ||
709 | s->status = COMMENT_STATE; | ||
710 | } | ||
711 | if (s->status == COMMENT_STATE) { | ||
712 | if (s->gzhead->comment != NULL) { | ||
713 | uInt beg = s->pending; /* start of bytes to update crc */ | ||
714 | int val; | ||
715 | |||
716 | do { | ||
717 | if (s->pending == s->pending_buf_size) { | ||
718 | if (s->gzhead->hcrc && s->pending > beg) | ||
719 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
720 | s->pending - beg); | ||
721 | flush_pending(strm); | ||
722 | beg = s->pending; | ||
723 | if (s->pending == s->pending_buf_size) { | ||
724 | val = 1; | ||
725 | break; | ||
726 | } | ||
727 | } | ||
728 | val = s->gzhead->comment[s->gzindex++]; | ||
729 | put_byte(s, val); | ||
730 | } while (val != 0); | ||
731 | if (s->gzhead->hcrc && s->pending > beg) | ||
732 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | ||
733 | s->pending - beg); | ||
734 | if (val == 0) | ||
735 | s->status = HCRC_STATE; | ||
736 | } | ||
737 | else | ||
738 | s->status = HCRC_STATE; | ||
739 | } | ||
740 | if (s->status == HCRC_STATE) { | ||
741 | if (s->gzhead->hcrc) { | ||
742 | if (s->pending + 2 > s->pending_buf_size) | ||
743 | flush_pending(strm); | ||
744 | if (s->pending + 2 <= s->pending_buf_size) { | ||
745 | put_byte(s, (Byte)(strm->adler & 0xff)); | ||
746 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | ||
747 | strm->adler = crc32(0L, Z_NULL, 0); | ||
748 | s->status = BUSY_STATE; | ||
749 | } | ||
750 | } | ||
751 | else | ||
752 | s->status = BUSY_STATE; | ||
753 | } | ||
754 | #endif | ||
755 | |||
756 | /* Flush as much pending output as possible */ | ||
757 | if (s->pending != 0) { | ||
758 | flush_pending(strm); | ||
759 | if (strm->avail_out == 0) { | ||
760 | /* Since avail_out is 0, deflate will be called again with | ||
761 | * more output space, but possibly with both pending and | ||
762 | * avail_in equal to zero. There won't be anything to do, | ||
763 | * but this is not an error situation so make sure we | ||
764 | * return OK instead of BUF_ERROR at next call of deflate: | ||
765 | */ | ||
766 | s->last_flush = -1; | ||
767 | return Z_OK; | ||
768 | } | ||
769 | |||
770 | /* Make sure there is something to do and avoid duplicate consecutive | ||
771 | * flushes. For repeated and useless calls with Z_FINISH, we keep | ||
772 | * returning Z_STREAM_END instead of Z_BUF_ERROR. | ||
773 | */ | ||
774 | } else if (strm->avail_in == 0 && flush <= old_flush && | ||
775 | flush != Z_FINISH) { | ||
776 | ERR_RETURN(strm, Z_BUF_ERROR); | ||
777 | } | ||
778 | |||
779 | /* User must not provide more input after the first FINISH: */ | ||
780 | if (s->status == FINISH_STATE && strm->avail_in != 0) { | ||
781 | ERR_RETURN(strm, Z_BUF_ERROR); | ||
782 | } | ||
783 | |||
784 | /* Start a new block or continue the current one. | ||
785 | */ | ||
786 | if (strm->avail_in != 0 || s->lookahead != 0 || | ||
787 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { | ||
788 | block_state bstate; | ||
789 | |||
790 | bstate = (*(configuration_table[s->level].func))(s, flush); | ||
791 | |||
792 | if (bstate == finish_started || bstate == finish_done) { | ||
793 | s->status = FINISH_STATE; | ||
794 | } | ||
795 | if (bstate == need_more || bstate == finish_started) { | ||
796 | if (strm->avail_out == 0) { | ||
797 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ | ||
798 | } | ||
799 | return Z_OK; | ||
800 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call | ||
801 | * of deflate should use the same flush parameter to make sure | ||
802 | * that the flush is complete. So we don't have to output an | ||
803 | * empty block here, this will be done at next call. This also | ||
804 | * ensures that for a very small output buffer, we emit at most | ||
805 | * one empty block. | ||
806 | */ | ||
807 | } | ||
808 | if (bstate == block_done) { | ||
809 | if (flush == Z_PARTIAL_FLUSH) { | ||
810 | _tr_align(s); | ||
811 | } else { /* FULL_FLUSH or SYNC_FLUSH */ | ||
812 | _tr_stored_block(s, (char*)0, 0L, 0); | ||
813 | /* For a full flush, this empty block will be recognized | ||
814 | * as a special marker by inflate_sync(). | ||
815 | */ | ||
816 | if (flush == Z_FULL_FLUSH) { | ||
817 | CLEAR_HASH(s); /* forget history */ | ||
818 | } | ||
819 | } | ||
820 | flush_pending(strm); | ||
821 | if (strm->avail_out == 0) { | ||
822 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ | ||
823 | return Z_OK; | ||
824 | } | ||
825 | } | ||
826 | } | ||
827 | Assert(strm->avail_out > 0, "bug2"); | ||
828 | |||
829 | if (flush != Z_FINISH) return Z_OK; | ||
830 | if (s->wrap <= 0) return Z_STREAM_END; | ||
831 | |||
832 | /* Write the trailer */ | ||
833 | #ifdef GZIP | ||
834 | if (s->wrap == 2) { | ||
835 | put_byte(s, (Byte)(strm->adler & 0xff)); | ||
836 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | ||
837 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); | ||
838 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); | ||
839 | put_byte(s, (Byte)(strm->total_in & 0xff)); | ||
840 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); | ||
841 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); | ||
842 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); | ||
843 | } | ||
844 | else | ||
845 | #endif | ||
846 | { | ||
847 | putShortMSB(s, (uInt)(strm->adler >> 16)); | ||
848 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | ||
849 | } | ||
850 | flush_pending(strm); | ||
851 | /* If avail_out is zero, the application will call deflate again | ||
852 | * to flush the rest. | ||
853 | */ | ||
854 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ | ||
855 | return s->pending != 0 ? Z_OK : Z_STREAM_END; | ||
856 | } | ||
857 | |||
858 | /* ========================================================================= */ | ||
859 | int ZEXPORT deflateEnd (strm) | ||
860 | z_streamp strm; | ||
861 | { | ||
862 | int status; | ||
863 | |||
864 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | ||
865 | |||
866 | status = strm->state->status; | ||
867 | if (status != INIT_STATE && | ||
868 | status != EXTRA_STATE && | ||
869 | status != NAME_STATE && | ||
870 | status != COMMENT_STATE && | ||
871 | status != HCRC_STATE && | ||
872 | status != BUSY_STATE && | ||
873 | status != FINISH_STATE) { | ||
874 | return Z_STREAM_ERROR; | ||
875 | } | ||
876 | |||
877 | /* Deallocate in reverse order of allocations: */ | ||
878 | TRY_FREE(strm, strm->state->pending_buf); | ||
879 | TRY_FREE(strm, strm->state->head); | ||
880 | TRY_FREE(strm, strm->state->prev); | ||
881 | TRY_FREE(strm, strm->state->window); | ||
882 | |||
883 | ZFREE(strm, strm->state); | ||
884 | strm->state = Z_NULL; | ||
885 | |||
886 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; | ||
887 | } | ||
888 | |||
889 | /* ========================================================================= | ||
890 | * Copy the source state to the destination state. | ||
891 | * To simplify the source, this is not supported for 16-bit MSDOS (which | ||
892 | * doesn't have enough memory anyway to duplicate compression states). | ||
893 | */ | ||
894 | int ZEXPORT deflateCopy (dest, source) | ||
895 | z_streamp dest; | ||
896 | z_streamp source; | ||
897 | { | ||
898 | #ifdef MAXSEG_64K | ||
899 | return Z_STREAM_ERROR; | ||
900 | #else | ||
901 | deflate_state *ds; | ||
902 | deflate_state *ss; | ||
903 | ushf *overlay; | ||
904 | |||
905 | |||
906 | if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { | ||
907 | return Z_STREAM_ERROR; | ||
908 | } | ||
909 | |||
910 | ss = source->state; | ||
911 | |||
912 | zmemcpy(dest, source, sizeof(z_stream)); | ||
913 | |||
914 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); | ||
915 | if (ds == Z_NULL) return Z_MEM_ERROR; | ||
916 | dest->state = (struct internal_state FAR *) ds; | ||
917 | zmemcpy(ds, ss, sizeof(deflate_state)); | ||
918 | ds->strm = dest; | ||
919 | |||
920 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); | ||
921 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); | ||
922 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); | ||
923 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); | ||
924 | ds->pending_buf = (uchf *) overlay; | ||
925 | |||
926 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || | ||
927 | ds->pending_buf == Z_NULL) { | ||
928 | deflateEnd (dest); | ||
929 | return Z_MEM_ERROR; | ||
930 | } | ||
931 | /* following zmemcpy do not work for 16-bit MSDOS */ | ||
932 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); | ||
933 | zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); | ||
934 | zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); | ||
935 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); | ||
936 | |||
937 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); | ||
938 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); | ||
939 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; | ||
940 | |||
941 | ds->l_desc.dyn_tree = ds->dyn_ltree; | ||
942 | ds->d_desc.dyn_tree = ds->dyn_dtree; | ||
943 | ds->bl_desc.dyn_tree = ds->bl_tree; | ||
944 | |||
945 | return Z_OK; | ||
946 | #endif /* MAXSEG_64K */ | ||
947 | } | ||
948 | |||
949 | /* =========================================================================== | ||
950 | * Read a new buffer from the current input stream, update the adler32 | ||
951 | * and total number of bytes read. All deflate() input goes through | ||
952 | * this function so some applications may wish to modify it to avoid | ||
953 | * allocating a large strm->next_in buffer and copying from it. | ||
954 | * (See also flush_pending()). | ||
955 | */ | ||
956 | local int read_buf(strm, buf, size) | ||
957 | z_streamp strm; | ||
958 | Bytef *buf; | ||
959 | unsigned size; | ||
960 | { | ||
961 | unsigned len = strm->avail_in; | ||
962 | |||
963 | if (len > size) len = size; | ||
964 | if (len == 0) return 0; | ||
965 | |||
966 | strm->avail_in -= len; | ||
967 | |||
968 | if (strm->state->wrap == 1) { | ||
969 | strm->adler = adler32(strm->adler, strm->next_in, len); | ||
970 | } | ||
971 | #ifdef GZIP | ||
972 | else if (strm->state->wrap == 2) { | ||
973 | strm->adler = crc32(strm->adler, strm->next_in, len); | ||
974 | } | ||
975 | #endif | ||
976 | zmemcpy(buf, strm->next_in, len); | ||
977 | strm->next_in += len; | ||
978 | strm->total_in += len; | ||
979 | |||
980 | return (int)len; | ||
981 | } | ||
982 | |||
983 | /* =========================================================================== | ||
984 | * Initialize the "longest match" routines for a new zlib stream | ||
985 | */ | ||
986 | local void lm_init (s) | ||
987 | deflate_state *s; | ||
988 | { | ||
989 | s->window_size = (ulg)2L*s->w_size; | ||
990 | |||
991 | CLEAR_HASH(s); | ||
992 | |||
993 | /* Set the default configuration parameters: | ||
994 | */ | ||
995 | s->max_lazy_match = configuration_table[s->level].max_lazy; | ||
996 | s->good_match = configuration_table[s->level].good_length; | ||
997 | s->nice_match = configuration_table[s->level].nice_length; | ||
998 | s->max_chain_length = configuration_table[s->level].max_chain; | ||
999 | |||
1000 | s->strstart = 0; | ||
1001 | s->block_start = 0L; | ||
1002 | s->lookahead = 0; | ||
1003 | s->match_length = s->prev_length = MIN_MATCH-1; | ||
1004 | s->match_available = 0; | ||
1005 | s->ins_h = 0; | ||
1006 | #ifndef FASTEST | ||
1007 | #ifdef ASMV | ||
1008 | match_init(); /* initialize the asm code */ | ||
1009 | #endif | ||
1010 | #endif | ||
1011 | } | ||
1012 | |||
1013 | #ifndef FASTEST | ||
1014 | /* =========================================================================== | ||
1015 | * Set match_start to the longest match starting at the given string and | ||
1016 | * return its length. Matches shorter or equal to prev_length are discarded, | ||
1017 | * in which case the result is equal to prev_length and match_start is | ||
1018 | * garbage. | ||
1019 | * IN assertions: cur_match is the head of the hash chain for the current | ||
1020 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | ||
1021 | * OUT assertion: the match length is not greater than s->lookahead. | ||
1022 | */ | ||
1023 | #ifndef ASMV | ||
1024 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or | ||
1025 | * match.S. The code will be functionally equivalent. | ||
1026 | */ | ||
1027 | local uInt longest_match(s, cur_match) | ||
1028 | deflate_state *s; | ||
1029 | IPos cur_match; /* current match */ | ||
1030 | { | ||
1031 | unsigned chain_length = s->max_chain_length;/* max hash chain length */ | ||
1032 | register Bytef *scan = s->window + s->strstart; /* current string */ | ||
1033 | register Bytef *match; /* matched string */ | ||
1034 | register int len; /* length of current match */ | ||
1035 | int best_len = s->prev_length; /* best match length so far */ | ||
1036 | int nice_match = s->nice_match; /* stop if match long enough */ | ||
1037 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | ||
1038 | s->strstart - (IPos)MAX_DIST(s) : NIL; | ||
1039 | /* Stop when cur_match becomes <= limit. To simplify the code, | ||
1040 | * we prevent matches with the string of window index 0. | ||
1041 | */ | ||
1042 | Posf *prev = s->prev; | ||
1043 | uInt wmask = s->w_mask; | ||
1044 | |||
1045 | #ifdef UNALIGNED_OK | ||
1046 | /* Compare two bytes at a time. Note: this is not always beneficial. | ||
1047 | * Try with and without -DUNALIGNED_OK to check. | ||
1048 | */ | ||
1049 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; | ||
1050 | register ush scan_start = *(ushf*)scan; | ||
1051 | register ush scan_end = *(ushf*)(scan+best_len-1); | ||
1052 | #else | ||
1053 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | ||
1054 | register Byte scan_end1 = scan[best_len-1]; | ||
1055 | register Byte scan_end = scan[best_len]; | ||
1056 | #endif | ||
1057 | |||
1058 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | ||
1059 | * It is easy to get rid of this optimization if necessary. | ||
1060 | */ | ||
1061 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | ||
1062 | |||
1063 | /* Do not waste too much time if we already have a good match: */ | ||
1064 | if (s->prev_length >= s->good_match) { | ||
1065 | chain_length >>= 2; | ||
1066 | } | ||
1067 | /* Do not look for matches beyond the end of the input. This is necessary | ||
1068 | * to make deflate deterministic. | ||
1069 | */ | ||
1070 | if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; | ||
1071 | |||
1072 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | ||
1073 | |||
1074 | do { | ||
1075 | Assert(cur_match < s->strstart, "no future"); | ||
1076 | match = s->window + cur_match; | ||
1077 | |||
1078 | /* Skip to next match if the match length cannot increase | ||
1079 | * or if the match length is less than 2. Note that the checks below | ||
1080 | * for insufficient lookahead only occur occasionally for performance | ||
1081 | * reasons. Therefore uninitialized memory will be accessed, and | ||
1082 | * conditional jumps will be made that depend on those values. | ||
1083 | * However the length of the match is limited to the lookahead, so | ||
1084 | * the output of deflate is not affected by the uninitialized values. | ||
1085 | */ | ||
1086 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) | ||
1087 | /* This code assumes sizeof(unsigned short) == 2. Do not use | ||
1088 | * UNALIGNED_OK if your compiler uses a different size. | ||
1089 | */ | ||
1090 | if (*(ushf*)(match+best_len-1) != scan_end || | ||
1091 | *(ushf*)match != scan_start) continue; | ||
1092 | |||
1093 | /* It is not necessary to compare scan[2] and match[2] since they are | ||
1094 | * always equal when the other bytes match, given that the hash keys | ||
1095 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at | ||
1096 | * strstart+3, +5, ... up to strstart+257. We check for insufficient | ||
1097 | * lookahead only every 4th comparison; the 128th check will be made | ||
1098 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is | ||
1099 | * necessary to put more guard bytes at the end of the window, or | ||
1100 | * to check more often for insufficient lookahead. | ||
1101 | */ | ||
1102 | Assert(scan[2] == match[2], "scan[2]?"); | ||
1103 | scan++, match++; | ||
1104 | do { | ||
1105 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | ||
1106 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | ||
1107 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | ||
1108 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | ||
1109 | scan < strend); | ||
1110 | /* The funny "do {}" generates better code on most compilers */ | ||
1111 | |||
1112 | /* Here, scan <= window+strstart+257 */ | ||
1113 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | ||
1114 | if (*scan == *match) scan++; | ||
1115 | |||
1116 | len = (MAX_MATCH - 1) - (int)(strend-scan); | ||
1117 | scan = strend - (MAX_MATCH-1); | ||
1118 | |||
1119 | #else /* UNALIGNED_OK */ | ||
1120 | |||
1121 | if (match[best_len] != scan_end || | ||
1122 | match[best_len-1] != scan_end1 || | ||
1123 | *match != *scan || | ||
1124 | *++match != scan[1]) continue; | ||
1125 | |||
1126 | /* The check at best_len-1 can be removed because it will be made | ||
1127 | * again later. (This heuristic is not always a win.) | ||
1128 | * It is not necessary to compare scan[2] and match[2] since they | ||
1129 | * are always equal when the other bytes match, given that | ||
1130 | * the hash keys are equal and that HASH_BITS >= 8. | ||
1131 | */ | ||
1132 | scan += 2, match++; | ||
1133 | Assert(*scan == *match, "match[2]?"); | ||
1134 | |||
1135 | /* We check for insufficient lookahead only every 8th comparison; | ||
1136 | * the 256th check will be made at strstart+258. | ||
1137 | */ | ||
1138 | do { | ||
1139 | } while (*++scan == *++match && *++scan == *++match && | ||
1140 | *++scan == *++match && *++scan == *++match && | ||
1141 | *++scan == *++match && *++scan == *++match && | ||
1142 | *++scan == *++match && *++scan == *++match && | ||
1143 | scan < strend); | ||
1144 | |||
1145 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | ||
1146 | |||
1147 | len = MAX_MATCH - (int)(strend - scan); | ||
1148 | scan = strend - MAX_MATCH; | ||
1149 | |||
1150 | #endif /* UNALIGNED_OK */ | ||
1151 | |||
1152 | if (len > best_len) { | ||
1153 | s->match_start = cur_match; | ||
1154 | best_len = len; | ||
1155 | if (len >= nice_match) break; | ||
1156 | #ifdef UNALIGNED_OK | ||
1157 | scan_end = *(ushf*)(scan+best_len-1); | ||
1158 | #else | ||
1159 | scan_end1 = scan[best_len-1]; | ||
1160 | scan_end = scan[best_len]; | ||
1161 | #endif | ||
1162 | } | ||
1163 | } while ((cur_match = prev[cur_match & wmask]) > limit | ||
1164 | && --chain_length != 0); | ||
1165 | |||
1166 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | ||
1167 | return s->lookahead; | ||
1168 | } | ||
1169 | #endif /* ASMV */ | ||
1170 | #endif /* FASTEST */ | ||
1171 | |||
1172 | /* --------------------------------------------------------------------------- | ||
1173 | * Optimized version for level == 1 or strategy == Z_RLE only | ||
1174 | */ | ||
1175 | local uInt longest_match_fast(s, cur_match) | ||
1176 | deflate_state *s; | ||
1177 | IPos cur_match; /* current match */ | ||
1178 | { | ||
1179 | register Bytef *scan = s->window + s->strstart; /* current string */ | ||
1180 | register Bytef *match; /* matched string */ | ||
1181 | register int len; /* length of current match */ | ||
1182 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | ||
1183 | |||
1184 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | ||
1185 | * It is easy to get rid of this optimization if necessary. | ||
1186 | */ | ||
1187 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | ||
1188 | |||
1189 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | ||
1190 | |||
1191 | Assert(cur_match < s->strstart, "no future"); | ||
1192 | |||
1193 | match = s->window + cur_match; | ||
1194 | |||
1195 | /* Return failure if the match length is less than 2: | ||
1196 | */ | ||
1197 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; | ||
1198 | |||
1199 | /* The check at best_len-1 can be removed because it will be made | ||
1200 | * again later. (This heuristic is not always a win.) | ||
1201 | * It is not necessary to compare scan[2] and match[2] since they | ||
1202 | * are always equal when the other bytes match, given that | ||
1203 | * the hash keys are equal and that HASH_BITS >= 8. | ||
1204 | */ | ||
1205 | scan += 2, match += 2; | ||
1206 | Assert(*scan == *match, "match[2]?"); | ||
1207 | |||
1208 | /* We check for insufficient lookahead only every 8th comparison; | ||
1209 | * the 256th check will be made at strstart+258. | ||
1210 | */ | ||
1211 | do { | ||
1212 | } while (*++scan == *++match && *++scan == *++match && | ||
1213 | *++scan == *++match && *++scan == *++match && | ||
1214 | *++scan == *++match && *++scan == *++match && | ||
1215 | *++scan == *++match && *++scan == *++match && | ||
1216 | scan < strend); | ||
1217 | |||
1218 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | ||
1219 | |||
1220 | len = MAX_MATCH - (int)(strend - scan); | ||
1221 | |||
1222 | if (len < MIN_MATCH) return MIN_MATCH - 1; | ||
1223 | |||
1224 | s->match_start = cur_match; | ||
1225 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; | ||
1226 | } | ||
1227 | |||
1228 | #ifdef DEBUG | ||
1229 | /* =========================================================================== | ||
1230 | * Check that the match at match_start is indeed a match. | ||
1231 | */ | ||
1232 | local void check_match(s, start, match, length) | ||
1233 | deflate_state *s; | ||
1234 | IPos start, match; | ||
1235 | int length; | ||
1236 | { | ||
1237 | /* check that the match is indeed a match */ | ||
1238 | if (zmemcmp(s->window + match, | ||
1239 | s->window + start, length) != EQUAL) { | ||
1240 | fprintf(stderr, " start %u, match %u, length %d\n", | ||
1241 | start, match, length); | ||
1242 | do { | ||
1243 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); | ||
1244 | } while (--length != 0); | ||
1245 | z_error("invalid match"); | ||
1246 | } | ||
1247 | if (z_verbose > 1) { | ||
1248 | fprintf(stderr,"\\[%d,%d]", start-match, length); | ||
1249 | do { putc(s->window[start++], stderr); } while (--length != 0); | ||
1250 | } | ||
1251 | } | ||
1252 | #else | ||
1253 | # define check_match(s, start, match, length) | ||
1254 | #endif /* DEBUG */ | ||
1255 | |||
1256 | /* =========================================================================== | ||
1257 | * Fill the window when the lookahead becomes insufficient. | ||
1258 | * Updates strstart and lookahead. | ||
1259 | * | ||
1260 | * IN assertion: lookahead < MIN_LOOKAHEAD | ||
1261 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD | ||
1262 | * At least one byte has been read, or avail_in == 0; reads are | ||
1263 | * performed for at least two bytes (required for the zip translate_eol | ||
1264 | * option -- not supported here). | ||
1265 | */ | ||
1266 | local void fill_window(s) | ||
1267 | deflate_state *s; | ||
1268 | { | ||
1269 | register unsigned n, m; | ||
1270 | register Posf *p; | ||
1271 | unsigned more; /* Amount of free space at the end of the window. */ | ||
1272 | uInt wsize = s->w_size; | ||
1273 | |||
1274 | do { | ||
1275 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); | ||
1276 | |||
1277 | /* Deal with !@#$% 64K limit: */ | ||
1278 | if (sizeof(int) <= 2) { | ||
1279 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) { | ||
1280 | more = wsize; | ||
1281 | |||
1282 | } else if (more == (unsigned)(-1)) { | ||
1283 | /* Very unlikely, but possible on 16 bit machine if | ||
1284 | * strstart == 0 && lookahead == 1 (input done a byte at time) | ||
1285 | */ | ||
1286 | more--; | ||
1287 | } | ||
1288 | } | ||
1289 | |||
1290 | /* If the window is almost full and there is insufficient lookahead, | ||
1291 | * move the upper half to the lower one to make room in the upper half. | ||
1292 | */ | ||
1293 | if (s->strstart >= wsize+MAX_DIST(s)) { | ||
1294 | |||
1295 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize); | ||
1296 | s->match_start -= wsize; | ||
1297 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ | ||
1298 | s->block_start -= (long) wsize; | ||
1299 | |||
1300 | /* Slide the hash table (could be avoided with 32 bit values | ||
1301 | at the expense of memory usage). We slide even when level == 0 | ||
1302 | to keep the hash table consistent if we switch back to level > 0 | ||
1303 | later. (Using level 0 permanently is not an optimal usage of | ||
1304 | zlib, so we don't care about this pathological case.) | ||
1305 | */ | ||
1306 | /* %%% avoid this when Z_RLE */ | ||
1307 | n = s->hash_size; | ||
1308 | p = &s->head[n]; | ||
1309 | do { | ||
1310 | m = *--p; | ||
1311 | *p = (Pos)(m >= wsize ? m-wsize : NIL); | ||
1312 | } while (--n); | ||
1313 | |||
1314 | n = wsize; | ||
1315 | #ifndef FASTEST | ||
1316 | p = &s->prev[n]; | ||
1317 | do { | ||
1318 | m = *--p; | ||
1319 | *p = (Pos)(m >= wsize ? m-wsize : NIL); | ||
1320 | /* If n is not on any hash chain, prev[n] is garbage but | ||
1321 | * its value will never be used. | ||
1322 | */ | ||
1323 | } while (--n); | ||
1324 | #endif | ||
1325 | more += wsize; | ||
1326 | } | ||
1327 | if (s->strm->avail_in == 0) return; | ||
1328 | |||
1329 | /* If there was no sliding: | ||
1330 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && | ||
1331 | * more == window_size - lookahead - strstart | ||
1332 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) | ||
1333 | * => more >= window_size - 2*WSIZE + 2 | ||
1334 | * In the BIG_MEM or MMAP case (not yet supported), | ||
1335 | * window_size == input_size + MIN_LOOKAHEAD && | ||
1336 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. | ||
1337 | * Otherwise, window_size == 2*WSIZE so more >= 2. | ||
1338 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2. | ||
1339 | */ | ||
1340 | Assert(more >= 2, "more < 2"); | ||
1341 | |||
1342 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); | ||
1343 | s->lookahead += n; | ||
1344 | |||
1345 | /* Initialize the hash value now that we have some input: */ | ||
1346 | if (s->lookahead >= MIN_MATCH) { | ||
1347 | s->ins_h = s->window[s->strstart]; | ||
1348 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | ||
1349 | #if MIN_MATCH != 3 | ||
1350 | Call UPDATE_HASH() MIN_MATCH-3 more times | ||
1351 | #endif | ||
1352 | } | ||
1353 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, | ||
1354 | * but this is not important since only literal bytes will be emitted. | ||
1355 | */ | ||
1356 | |||
1357 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); | ||
1358 | } | ||
1359 | |||
1360 | /* =========================================================================== | ||
1361 | * Flush the current block, with given end-of-file flag. | ||
1362 | * IN assertion: strstart is set to the end of the current match. | ||
1363 | */ | ||
1364 | #define FLUSH_BLOCK_ONLY(s, eof) { \ | ||
1365 | _tr_flush_block(s, (s->block_start >= 0L ? \ | ||
1366 | (charf *)&s->window[(unsigned)s->block_start] : \ | ||
1367 | (charf *)Z_NULL), \ | ||
1368 | (ulg)((long)s->strstart - s->block_start), \ | ||
1369 | (eof)); \ | ||
1370 | s->block_start = s->strstart; \ | ||
1371 | flush_pending(s->strm); \ | ||
1372 | Tracev((stderr,"[FLUSH]")); \ | ||
1373 | } | ||
1374 | |||
1375 | /* Same but force premature exit if necessary. */ | ||
1376 | #define FLUSH_BLOCK(s, eof) { \ | ||
1377 | FLUSH_BLOCK_ONLY(s, eof); \ | ||
1378 | if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ | ||
1379 | } | ||
1380 | |||
1381 | /* =========================================================================== | ||
1382 | * Copy without compression as much as possible from the input stream, return | ||
1383 | * the current block state. | ||
1384 | * This function does not insert new strings in the dictionary since | ||
1385 | * uncompressible data is probably not useful. This function is used | ||
1386 | * only for the level=0 compression option. | ||
1387 | * NOTE: this function should be optimized to avoid extra copying from | ||
1388 | * window to pending_buf. | ||
1389 | */ | ||
1390 | local block_state deflate_stored(s, flush) | ||
1391 | deflate_state *s; | ||
1392 | int flush; | ||
1393 | { | ||
1394 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited | ||
1395 | * to pending_buf_size, and each stored block has a 5 byte header: | ||
1396 | */ | ||
1397 | ulg max_block_size = 0xffff; | ||
1398 | ulg max_start; | ||
1399 | |||
1400 | if (max_block_size > s->pending_buf_size - 5) { | ||
1401 | max_block_size = s->pending_buf_size - 5; | ||
1402 | } | ||
1403 | |||
1404 | /* Copy as much as possible from input to output: */ | ||
1405 | for (;;) { | ||
1406 | /* Fill the window as much as possible: */ | ||
1407 | if (s->lookahead <= 1) { | ||
1408 | |||
1409 | Assert(s->strstart < s->w_size+MAX_DIST(s) || | ||
1410 | s->block_start >= (long)s->w_size, "slide too late"); | ||
1411 | |||
1412 | fill_window(s); | ||
1413 | if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; | ||
1414 | |||
1415 | if (s->lookahead == 0) break; /* flush the current block */ | ||
1416 | } | ||
1417 | Assert(s->block_start >= 0L, "block gone"); | ||
1418 | |||
1419 | s->strstart += s->lookahead; | ||
1420 | s->lookahead = 0; | ||
1421 | |||
1422 | /* Emit a stored block if pending_buf will be full: */ | ||
1423 | max_start = s->block_start + max_block_size; | ||
1424 | if (s->strstart == 0 || (ulg)s->strstart >= max_start) { | ||
1425 | /* strstart == 0 is possible when wraparound on 16-bit machine */ | ||
1426 | s->lookahead = (uInt)(s->strstart - max_start); | ||
1427 | s->strstart = (uInt)max_start; | ||
1428 | FLUSH_BLOCK(s, 0); | ||
1429 | } | ||
1430 | /* Flush if we may have to slide, otherwise block_start may become | ||
1431 | * negative and the data will be gone: | ||
1432 | */ | ||
1433 | if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { | ||
1434 | FLUSH_BLOCK(s, 0); | ||
1435 | } | ||
1436 | } | ||
1437 | FLUSH_BLOCK(s, flush == Z_FINISH); | ||
1438 | return flush == Z_FINISH ? finish_done : block_done; | ||
1439 | } | ||
1440 | |||
1441 | /* =========================================================================== | ||
1442 | * Compress as much as possible from the input stream, return the current | ||
1443 | * block state. | ||
1444 | * This function does not perform lazy evaluation of matches and inserts | ||
1445 | * new strings in the dictionary only for unmatched strings or for short | ||
1446 | * matches. It is used only for the fast compression options. | ||
1447 | */ | ||
1448 | local block_state deflate_fast(s, flush) | ||
1449 | deflate_state *s; | ||
1450 | int flush; | ||
1451 | { | ||
1452 | IPos hash_head = NIL; /* head of the hash chain */ | ||
1453 | int bflush; /* set if current block must be flushed */ | ||
1454 | |||
1455 | for (;;) { | ||
1456 | /* Make sure that we always have enough lookahead, except | ||
1457 | * at the end of the input file. We need MAX_MATCH bytes | ||
1458 | * for the next match, plus MIN_MATCH bytes to insert the | ||
1459 | * string following the next match. | ||
1460 | */ | ||
1461 | if (s->lookahead < MIN_LOOKAHEAD) { | ||
1462 | fill_window(s); | ||
1463 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | ||
1464 | return need_more; | ||
1465 | } | ||
1466 | if (s->lookahead == 0) break; /* flush the current block */ | ||
1467 | } | ||
1468 | |||
1469 | /* Insert the string window[strstart .. strstart+2] in the | ||
1470 | * dictionary, and set hash_head to the head of the hash chain: | ||
1471 | */ | ||
1472 | if (s->lookahead >= MIN_MATCH) { | ||
1473 | INSERT_STRING(s, s->strstart, hash_head); | ||
1474 | } | ||
1475 | |||
1476 | /* Find the longest match, discarding those <= prev_length. | ||
1477 | * At this point we have always match_length < MIN_MATCH | ||
1478 | */ | ||
1479 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { | ||
1480 | /* To simplify the code, we prevent matches with the string | ||
1481 | * of window index 0 (in particular we have to avoid a match | ||
1482 | * of the string with itself at the start of the input file). | ||
1483 | */ | ||
1484 | #ifdef FASTEST | ||
1485 | if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) || | ||
1486 | (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { | ||
1487 | s->match_length = longest_match_fast (s, hash_head); | ||
1488 | } | ||
1489 | #else | ||
1490 | if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { | ||
1491 | s->match_length = longest_match (s, hash_head); | ||
1492 | } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { | ||
1493 | s->match_length = longest_match_fast (s, hash_head); | ||
1494 | } | ||
1495 | #endif | ||
1496 | /* longest_match() or longest_match_fast() sets match_start */ | ||
1497 | } | ||
1498 | if (s->match_length >= MIN_MATCH) { | ||
1499 | check_match(s, s->strstart, s->match_start, s->match_length); | ||
1500 | |||
1501 | _tr_tally_dist(s, s->strstart - s->match_start, | ||
1502 | s->match_length - MIN_MATCH, bflush); | ||
1503 | |||
1504 | s->lookahead -= s->match_length; | ||
1505 | |||
1506 | /* Insert new strings in the hash table only if the match length | ||
1507 | * is not too large. This saves time but degrades compression. | ||
1508 | */ | ||
1509 | #ifndef FASTEST | ||
1510 | if (s->match_length <= s->max_insert_length && | ||
1511 | s->lookahead >= MIN_MATCH) { | ||
1512 | s->match_length--; /* string at strstart already in table */ | ||
1513 | do { | ||
1514 | s->strstart++; | ||
1515 | INSERT_STRING(s, s->strstart, hash_head); | ||
1516 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are | ||
1517 | * always MIN_MATCH bytes ahead. | ||
1518 | */ | ||
1519 | } while (--s->match_length != 0); | ||
1520 | s->strstart++; | ||
1521 | } else | ||
1522 | #endif | ||
1523 | { | ||
1524 | s->strstart += s->match_length; | ||
1525 | s->match_length = 0; | ||
1526 | s->ins_h = s->window[s->strstart]; | ||
1527 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | ||
1528 | #if MIN_MATCH != 3 | ||
1529 | Call UPDATE_HASH() MIN_MATCH-3 more times | ||
1530 | #endif | ||
1531 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not | ||
1532 | * matter since it will be recomputed at next deflate call. | ||
1533 | */ | ||
1534 | } | ||
1535 | } else { | ||
1536 | /* No match, output a literal byte */ | ||
1537 | Tracevv((stderr,"%c", s->window[s->strstart])); | ||
1538 | _tr_tally_lit (s, s->window[s->strstart], bflush); | ||
1539 | s->lookahead--; | ||
1540 | s->strstart++; | ||
1541 | } | ||
1542 | if (bflush) FLUSH_BLOCK(s, 0); | ||
1543 | } | ||
1544 | FLUSH_BLOCK(s, flush == Z_FINISH); | ||
1545 | return flush == Z_FINISH ? finish_done : block_done; | ||
1546 | } | ||
1547 | |||
1548 | #ifndef FASTEST | ||
1549 | /* =========================================================================== | ||
1550 | * Same as above, but achieves better compression. We use a lazy | ||
1551 | * evaluation for matches: a match is finally adopted only if there is | ||
1552 | * no better match at the next window position. | ||
1553 | */ | ||
1554 | local block_state deflate_slow(s, flush) | ||
1555 | deflate_state *s; | ||
1556 | int flush; | ||
1557 | { | ||
1558 | IPos hash_head = NIL; /* head of hash chain */ | ||
1559 | int bflush; /* set if current block must be flushed */ | ||
1560 | |||
1561 | /* Process the input block. */ | ||
1562 | for (;;) { | ||
1563 | /* Make sure that we always have enough lookahead, except | ||
1564 | * at the end of the input file. We need MAX_MATCH bytes | ||
1565 | * for the next match, plus MIN_MATCH bytes to insert the | ||
1566 | * string following the next match. | ||
1567 | */ | ||
1568 | if (s->lookahead < MIN_LOOKAHEAD) { | ||
1569 | fill_window(s); | ||
1570 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | ||
1571 | return need_more; | ||
1572 | } | ||
1573 | if (s->lookahead == 0) break; /* flush the current block */ | ||
1574 | } | ||
1575 | |||
1576 | /* Insert the string window[strstart .. strstart+2] in the | ||
1577 | * dictionary, and set hash_head to the head of the hash chain: | ||
1578 | */ | ||
1579 | if (s->lookahead >= MIN_MATCH) { | ||
1580 | INSERT_STRING(s, s->strstart, hash_head); | ||
1581 | } | ||
1582 | |||
1583 | /* Find the longest match, discarding those <= prev_length. | ||
1584 | */ | ||
1585 | s->prev_length = s->match_length, s->prev_match = s->match_start; | ||
1586 | s->match_length = MIN_MATCH-1; | ||
1587 | |||
1588 | if (hash_head != NIL && s->prev_length < s->max_lazy_match && | ||
1589 | s->strstart - hash_head <= MAX_DIST(s)) { | ||
1590 | /* To simplify the code, we prevent matches with the string | ||
1591 | * of window index 0 (in particular we have to avoid a match | ||
1592 | * of the string with itself at the start of the input file). | ||
1593 | */ | ||
1594 | if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { | ||
1595 | s->match_length = longest_match (s, hash_head); | ||
1596 | } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { | ||
1597 | s->match_length = longest_match_fast (s, hash_head); | ||
1598 | } | ||
1599 | /* longest_match() or longest_match_fast() sets match_start */ | ||
1600 | |||
1601 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED | ||
1602 | #if TOO_FAR <= 32767 | ||
1603 | || (s->match_length == MIN_MATCH && | ||
1604 | s->strstart - s->match_start > TOO_FAR) | ||
1605 | #endif | ||
1606 | )) { | ||
1607 | |||
1608 | /* If prev_match is also MIN_MATCH, match_start is garbage | ||
1609 | * but we will ignore the current match anyway. | ||
1610 | */ | ||
1611 | s->match_length = MIN_MATCH-1; | ||
1612 | } | ||
1613 | } | ||
1614 | /* If there was a match at the previous step and the current | ||
1615 | * match is not better, output the previous match: | ||
1616 | */ | ||
1617 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { | ||
1618 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; | ||
1619 | /* Do not insert strings in hash table beyond this. */ | ||
1620 | |||
1621 | check_match(s, s->strstart-1, s->prev_match, s->prev_length); | ||
1622 | |||
1623 | _tr_tally_dist(s, s->strstart -1 - s->prev_match, | ||
1624 | s->prev_length - MIN_MATCH, bflush); | ||
1625 | |||
1626 | /* Insert in hash table all strings up to the end of the match. | ||
1627 | * strstart-1 and strstart are already inserted. If there is not | ||
1628 | * enough lookahead, the last two strings are not inserted in | ||
1629 | * the hash table. | ||
1630 | */ | ||
1631 | s->lookahead -= s->prev_length-1; | ||
1632 | s->prev_length -= 2; | ||
1633 | do { | ||
1634 | if (++s->strstart <= max_insert) { | ||
1635 | INSERT_STRING(s, s->strstart, hash_head); | ||
1636 | } | ||
1637 | } while (--s->prev_length != 0); | ||
1638 | s->match_available = 0; | ||
1639 | s->match_length = MIN_MATCH-1; | ||
1640 | s->strstart++; | ||
1641 | |||
1642 | if (bflush) FLUSH_BLOCK(s, 0); | ||
1643 | |||
1644 | } else if (s->match_available) { | ||
1645 | /* If there was no match at the previous position, output a | ||
1646 | * single literal. If there was a match but the current match | ||
1647 | * is longer, truncate the previous match to a single literal. | ||
1648 | */ | ||
1649 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | ||
1650 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); | ||
1651 | if (bflush) { | ||
1652 | FLUSH_BLOCK_ONLY(s, 0); | ||
1653 | } | ||
1654 | s->strstart++; | ||
1655 | s->lookahead--; | ||
1656 | if (s->strm->avail_out == 0) return need_more; | ||
1657 | } else { | ||
1658 | /* There is no previous match to compare with, wait for | ||
1659 | * the next step to decide. | ||
1660 | */ | ||
1661 | s->match_available = 1; | ||
1662 | s->strstart++; | ||
1663 | s->lookahead--; | ||
1664 | } | ||
1665 | } | ||
1666 | Assert (flush != Z_NO_FLUSH, "no flush?"); | ||
1667 | if (s->match_available) { | ||
1668 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | ||
1669 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); | ||
1670 | s->match_available = 0; | ||
1671 | } | ||
1672 | FLUSH_BLOCK(s, flush == Z_FINISH); | ||
1673 | return flush == Z_FINISH ? finish_done : block_done; | ||
1674 | } | ||
1675 | #endif /* FASTEST */ | ||
1676 | |||
1677 | #if 0 | ||
1678 | /* =========================================================================== | ||
1679 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance | ||
1680 | * one. Do not maintain a hash table. (It will be regenerated if this run of | ||
1681 | * deflate switches away from Z_RLE.) | ||
1682 | */ | ||
1683 | local block_state deflate_rle(s, flush) | ||
1684 | deflate_state *s; | ||
1685 | int flush; | ||
1686 | { | ||
1687 | int bflush; /* set if current block must be flushed */ | ||
1688 | uInt run; /* length of run */ | ||
1689 | uInt max; /* maximum length of run */ | ||
1690 | uInt prev; /* byte at distance one to match */ | ||
1691 | Bytef *scan; /* scan for end of run */ | ||
1692 | |||
1693 | for (;;) { | ||
1694 | /* Make sure that we always have enough lookahead, except | ||
1695 | * at the end of the input file. We need MAX_MATCH bytes | ||
1696 | * for the longest encodable run. | ||
1697 | */ | ||
1698 | if (s->lookahead < MAX_MATCH) { | ||
1699 | fill_window(s); | ||
1700 | if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { | ||
1701 | return need_more; | ||
1702 | } | ||
1703 | if (s->lookahead == 0) break; /* flush the current block */ | ||
1704 | } | ||
1705 | |||
1706 | /* See how many times the previous byte repeats */ | ||
1707 | run = 0; | ||
1708 | if (s->strstart > 0) { /* if there is a previous byte, that is */ | ||
1709 | max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH; | ||
1710 | scan = s->window + s->strstart - 1; | ||
1711 | prev = *scan++; | ||
1712 | do { | ||
1713 | if (*scan++ != prev) | ||
1714 | break; | ||
1715 | } while (++run < max); | ||
1716 | } | ||
1717 | |||
1718 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */ | ||
1719 | if (run >= MIN_MATCH) { | ||
1720 | check_match(s, s->strstart, s->strstart - 1, run); | ||
1721 | _tr_tally_dist(s, 1, run - MIN_MATCH, bflush); | ||
1722 | s->lookahead -= run; | ||
1723 | s->strstart += run; | ||
1724 | } else { | ||
1725 | /* No match, output a literal byte */ | ||
1726 | Tracevv((stderr,"%c", s->window[s->strstart])); | ||
1727 | _tr_tally_lit (s, s->window[s->strstart], bflush); | ||
1728 | s->lookahead--; | ||
1729 | s->strstart++; | ||
1730 | } | ||
1731 | if (bflush) FLUSH_BLOCK(s, 0); | ||
1732 | } | ||
1733 | FLUSH_BLOCK(s, flush == Z_FINISH); | ||
1734 | return flush == Z_FINISH ? finish_done : block_done; | ||
1735 | } | ||
1736 | #endif | ||