Commit | Line | Data |
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d4286ec4 | 1 | /* deflate.c -- compress data using the deflation algorithm |
cd426074 | 2 | * Copyright (C) 1995-2005 Jean-loup Gailly. |
1e1cf689 | 3 | * For conditions of distribution and use, see copyright notice in zlib.h |
d4286ec4 PM |
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". | |
1e1cf689 | 40 | * Available in http://www.ietf.org/rfc/rfc1951.txt |
d4286ec4 PM |
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 | ||
12febd80 WD |
54 | #define read_buf dread_buf |
55 | ||
d4286ec4 | 56 | const char deflate_copyright[] = |
cd426074 | 57 | " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; |
d4286ec4 PM |
58 | /* |
59 | If you use the zlib library in a product, an acknowledgment is welcome | |
60 | in the documentation of your product. If for some reason you cannot | |
61 | include such an acknowledgment, I would appreciate that you keep this | |
62 | copyright string in the executable of your product. | |
63 | */ | |
64 | ||
65 | /* =========================================================================== | |
66 | * Function prototypes. | |
67 | */ | |
68 | typedef enum { | |
69 | need_more, /* block not completed, need more input or more output */ | |
70 | block_done, /* block flush performed */ | |
71 | finish_started, /* finish started, need only more output at next deflate */ | |
72 | finish_done /* finish done, accept no more input or output */ | |
73 | } block_state; | |
74 | ||
75 | typedef block_state (*compress_func) OF((deflate_state *s, int flush)); | |
76 | /* Compression function. Returns the block state after the call. */ | |
77 | ||
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)); | |
1e1cf689 | 81 | #ifndef FASTEST |
d4286ec4 | 82 | local block_state deflate_slow OF((deflate_state *s, int flush)); |
1e1cf689 | 83 | #endif |
d4286ec4 PM |
84 | local void lm_init OF((deflate_state *s)); |
85 | local void putShortMSB OF((deflate_state *s, uInt b)); | |
86 | local void flush_pending OF((z_streamp strm)); | |
12febd80 | 87 | local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); |
1e1cf689 | 88 | #ifndef FASTEST |
d4286ec4 PM |
89 | #ifdef ASMV |
90 | void match_init OF((void)); /* asm code initialization */ | |
91 | uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
92 | #else | |
93 | local uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
94 | #endif | |
1e1cf689 WD |
95 | #endif |
96 | local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); | |
d4286ec4 PM |
97 | |
98 | #ifdef 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 | #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) | |
116 | /* Minimum amount of lookahead, except at the end of the input file. | |
117 | * See deflate.c for comments about the MIN_MATCH+1. | |
118 | */ | |
119 | ||
120 | /* Values for max_lazy_match, good_match and max_chain_length, depending on | |
121 | * the desired pack level (0..9). The values given below have been tuned to | |
122 | * exclude worst case performance for pathological files. Better values may be | |
123 | * found for specific files. | |
124 | */ | |
125 | typedef struct config_s { | |
126 | ush good_length; /* reduce lazy search above this match length */ | |
127 | ush max_lazy; /* do not perform lazy search above this match length */ | |
128 | ush nice_length; /* quit search above this match length */ | |
129 | ush max_chain; | |
130 | compress_func func; | |
131 | } config; | |
132 | ||
1e1cf689 WD |
133 | #ifdef FASTEST |
134 | local const config configuration_table[2] = { | |
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 | #else | |
d4286ec4 PM |
139 | local const config configuration_table[10] = { |
140 | /* good lazy nice chain */ | |
141 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
1e1cf689 | 142 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ |
d4286ec4 PM |
143 | /* 2 */ {4, 5, 16, 8, deflate_fast}, |
144 | /* 3 */ {4, 6, 32, 32, deflate_fast}, | |
145 | ||
146 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ | |
147 | /* 5 */ {8, 16, 32, 32, deflate_slow}, | |
148 | /* 6 */ {8, 16, 128, 128, deflate_slow}, | |
149 | /* 7 */ {8, 32, 128, 256, deflate_slow}, | |
150 | /* 8 */ {32, 128, 258, 1024, deflate_slow}, | |
1e1cf689 WD |
151 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ |
152 | #endif | |
d4286ec4 PM |
153 | |
154 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 | |
155 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different | |
156 | * meaning. | |
157 | */ | |
158 | ||
159 | #define EQUAL 0 | |
160 | /* result of memcmp for equal strings */ | |
161 | ||
1e1cf689 | 162 | #ifndef NO_DUMMY_DECL |
d4286ec4 | 163 | struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ |
1e1cf689 | 164 | #endif |
d4286ec4 PM |
165 | |
166 | /* =========================================================================== | |
167 | * Update a hash value with the given input byte | |
168 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive | |
169 | * input characters, so that a running hash key can be computed from the | |
170 | * previous key instead of complete recalculation each time. | |
171 | */ | |
172 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) | |
173 | ||
174 | ||
175 | /* =========================================================================== | |
176 | * Insert string str in the dictionary and set match_head to the previous head | |
177 | * of the hash chain (the most recent string with same hash key). Return | |
178 | * the previous length of the hash chain. | |
179 | * If this file is compiled with -DFASTEST, the compression level is forced | |
180 | * to 1, and no hash chains are maintained. | |
181 | * IN assertion: all calls to to INSERT_STRING are made with consecutive | |
182 | * input characters and the first MIN_MATCH bytes of str are valid | |
183 | * (except for the last MIN_MATCH-1 bytes of the input file). | |
184 | */ | |
185 | #ifdef FASTEST | |
186 | #define INSERT_STRING(s, str, match_head) \ | |
187 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
188 | match_head = s->head[s->ins_h], \ | |
189 | s->head[s->ins_h] = (Pos)(str)) | |
190 | #else | |
191 | #define INSERT_STRING(s, str, match_head) \ | |
192 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
1e1cf689 | 193 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ |
d4286ec4 PM |
194 | s->head[s->ins_h] = (Pos)(str)) |
195 | #endif | |
196 | ||
197 | /* =========================================================================== | |
198 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems). | |
199 | * prev[] will be initialized on the fly. | |
200 | */ | |
201 | #define CLEAR_HASH(s) \ | |
202 | s->head[s->hash_size-1] = NIL; \ | |
203 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); | |
204 | ||
205 | /* ========================================================================= */ | |
206 | int ZEXPORT deflateInit_(strm, level, version, stream_size) | |
207 | z_streamp strm; | |
208 | int level; | |
209 | const char *version; | |
210 | int stream_size; | |
211 | { | |
212 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, | |
1e1cf689 | 213 | Z_DEFAULT_STRATEGY, version, stream_size); |
d4286ec4 PM |
214 | /* To do: ignore strm->next_in if we use it as window */ |
215 | } | |
216 | ||
217 | /* ========================================================================= */ | |
218 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, | |
1e1cf689 | 219 | version, stream_size) |
d4286ec4 PM |
220 | z_streamp strm; |
221 | int level; | |
222 | int method; | |
223 | int windowBits; | |
224 | int memLevel; | |
225 | int strategy; | |
226 | const char *version; | |
227 | int stream_size; | |
228 | { | |
229 | deflate_state *s; | |
1e1cf689 WD |
230 | int wrap = 1; |
231 | static const char my_version[] = ZLIB_VERSION; | |
d4286ec4 PM |
232 | |
233 | ushf *overlay; | |
234 | /* We overlay pending_buf and d_buf+l_buf. This works since the average | |
235 | * output size for (length,distance) codes is <= 24 bits. | |
236 | */ | |
237 | ||
238 | if (version == Z_NULL || version[0] != my_version[0] || | |
239 | stream_size != sizeof(z_stream)) { | |
1e1cf689 | 240 | return Z_VERSION_ERROR; |
d4286ec4 PM |
241 | } |
242 | if (strm == Z_NULL) return Z_STREAM_ERROR; | |
243 | ||
244 | strm->msg = Z_NULL; | |
1e1cf689 WD |
245 | if (strm->zalloc == (alloc_func)0) { |
246 | strm->zalloc = zcalloc; | |
247 | strm->opaque = (voidpf)0; | |
d4286ec4 | 248 | } |
1e1cf689 | 249 | if (strm->zfree == (free_func)0) strm->zfree = zcfree; |
d4286ec4 | 250 | |
d4286ec4 | 251 | #ifdef FASTEST |
1e1cf689 WD |
252 | if (level != 0) level = 1; |
253 | #else | |
254 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
d4286ec4 PM |
255 | #endif |
256 | ||
1e1cf689 WD |
257 | if (windowBits < 0) { /* suppress zlib wrapper */ |
258 | wrap = 0; | |
d4286ec4 PM |
259 | windowBits = -windowBits; |
260 | } | |
1e1cf689 WD |
261 | #ifdef GZIP |
262 | else if (windowBits > 15) { | |
263 | wrap = 2; /* write gzip wrapper instead */ | |
264 | windowBits -= 16; | |
265 | } | |
266 | #endif | |
d4286ec4 | 267 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || |
1e1cf689 | 268 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || |
cd426074 | 269 | strategy < 0 || strategy > Z_FIXED) { |
d4286ec4 PM |
270 | return Z_STREAM_ERROR; |
271 | } | |
1e1cf689 | 272 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ |
d4286ec4 PM |
273 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); |
274 | if (s == Z_NULL) return Z_MEM_ERROR; | |
275 | strm->state = (struct internal_state FAR *)s; | |
276 | s->strm = strm; | |
277 | ||
1e1cf689 | 278 | s->wrap = wrap; |
cd426074 | 279 | s->gzhead = Z_NULL; |
d4286ec4 PM |
280 | s->w_bits = windowBits; |
281 | s->w_size = 1 << s->w_bits; | |
282 | s->w_mask = s->w_size - 1; | |
283 | ||
284 | s->hash_bits = memLevel + 7; | |
285 | s->hash_size = 1 << s->hash_bits; | |
286 | s->hash_mask = s->hash_size - 1; | |
287 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); | |
288 | ||
289 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); | |
290 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); | |
291 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); | |
292 | ||
293 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ | |
294 | ||
295 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); | |
296 | s->pending_buf = (uchf *) overlay; | |
297 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); | |
298 | ||
299 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || | |
300 | s->pending_buf == Z_NULL) { | |
1e1cf689 | 301 | s->status = FINISH_STATE; |
d4286ec4 PM |
302 | strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); |
303 | deflateEnd (strm); | |
304 | return Z_MEM_ERROR; | |
305 | } | |
306 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush); | |
307 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; | |
308 | ||
309 | s->level = level; | |
310 | s->strategy = strategy; | |
311 | s->method = (Byte)method; | |
312 | ||
313 | return deflateReset(strm); | |
314 | } | |
315 | ||
316 | /* ========================================================================= */ | |
317 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) | |
318 | z_streamp strm; | |
319 | const Bytef *dictionary; | |
320 | uInt dictLength; | |
321 | { | |
322 | deflate_state *s; | |
323 | uInt length = dictLength; | |
324 | uInt n; | |
325 | IPos hash_head = 0; | |
326 | ||
327 | if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || | |
1e1cf689 WD |
328 | strm->state->wrap == 2 || |
329 | (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) | |
330 | return Z_STREAM_ERROR; | |
d4286ec4 PM |
331 | |
332 | s = strm->state; | |
1e1cf689 WD |
333 | if (s->wrap) |
334 | strm->adler = adler32(strm->adler, dictionary, dictLength); | |
d4286ec4 PM |
335 | |
336 | if (length < MIN_MATCH) return Z_OK; | |
337 | if (length > MAX_DIST(s)) { | |
1e1cf689 | 338 | length = MAX_DIST(s); |
1e1cf689 | 339 | dictionary += dictLength - length; /* use the tail of the dictionary */ |
d4286ec4 PM |
340 | } |
341 | zmemcpy(s->window, dictionary, length); | |
342 | s->strstart = length; | |
343 | s->block_start = (long)length; | |
344 | ||
345 | /* Insert all strings in the hash table (except for the last two bytes). | |
346 | * s->lookahead stays null, so s->ins_h will be recomputed at the next | |
347 | * call of fill_window. | |
348 | */ | |
349 | s->ins_h = s->window[0]; | |
350 | UPDATE_HASH(s, s->ins_h, s->window[1]); | |
351 | for (n = 0; n <= length - MIN_MATCH; n++) { | |
1e1cf689 | 352 | INSERT_STRING(s, n, hash_head); |
d4286ec4 PM |
353 | } |
354 | if (hash_head) hash_head = 0; /* to make compiler happy */ | |
355 | return Z_OK; | |
356 | } | |
357 | ||
358 | /* ========================================================================= */ | |
359 | int ZEXPORT deflateReset (strm) | |
360 | z_streamp strm; | |
361 | { | |
362 | deflate_state *s; | |
1e1cf689 | 363 | |
d4286ec4 | 364 | if (strm == Z_NULL || strm->state == Z_NULL || |
1e1cf689 WD |
365 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { |
366 | return Z_STREAM_ERROR; | |
367 | } | |
d4286ec4 PM |
368 | |
369 | strm->total_in = strm->total_out = 0; | |
370 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ | |
371 | strm->data_type = Z_UNKNOWN; | |
372 | ||
373 | s = (deflate_state *)strm->state; | |
374 | s->pending = 0; | |
375 | s->pending_out = s->pending_buf; | |
376 | ||
1e1cf689 WD |
377 | if (s->wrap < 0) { |
378 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ | |
d4286ec4 | 379 | } |
1e1cf689 WD |
380 | s->status = s->wrap ? INIT_STATE : BUSY_STATE; |
381 | strm->adler = | |
382 | #ifdef GZIP | |
383 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) : | |
384 | #endif | |
385 | adler32(0L, Z_NULL, 0); | |
d4286ec4 PM |
386 | s->last_flush = Z_NO_FLUSH; |
387 | ||
388 | _tr_init(s); | |
389 | lm_init(s); | |
390 | ||
391 | return Z_OK; | |
392 | } | |
393 | ||
cd426074 WD |
394 | /* ========================================================================= */ |
395 | int ZEXPORT deflateSetHeader (strm, head) | |
396 | z_streamp strm; | |
397 | gz_headerp head; | |
398 | { | |
399 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
400 | if (strm->state->wrap != 2) return Z_STREAM_ERROR; | |
401 | strm->state->gzhead = head; | |
402 | return Z_OK; | |
403 | } | |
404 | ||
1e1cf689 WD |
405 | /* ========================================================================= */ |
406 | int ZEXPORT deflatePrime (strm, bits, value) | |
407 | z_streamp strm; | |
408 | int bits; | |
409 | int value; | |
410 | { | |
411 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
412 | strm->state->bi_valid = bits; | |
413 | strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); | |
414 | return Z_OK; | |
415 | } | |
416 | ||
d4286ec4 PM |
417 | /* ========================================================================= */ |
418 | int ZEXPORT deflateParams(strm, level, strategy) | |
419 | z_streamp strm; | |
420 | int level; | |
421 | int strategy; | |
422 | { | |
423 | deflate_state *s; | |
424 | compress_func func; | |
425 | int err = Z_OK; | |
426 | ||
427 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
428 | s = strm->state; | |
429 | ||
1e1cf689 WD |
430 | #ifdef FASTEST |
431 | if (level != 0) level = 1; | |
432 | #else | |
433 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
434 | #endif | |
cd426074 | 435 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { |
1e1cf689 | 436 | return Z_STREAM_ERROR; |
d4286ec4 PM |
437 | } |
438 | func = configuration_table[s->level].func; | |
439 | ||
440 | if (func != configuration_table[level].func && strm->total_in != 0) { | |
1e1cf689 WD |
441 | /* Flush the last buffer: */ |
442 | err = deflate(strm, Z_PARTIAL_FLUSH); | |
d4286ec4 PM |
443 | } |
444 | if (s->level != level) { | |
1e1cf689 WD |
445 | s->level = level; |
446 | s->max_lazy_match = configuration_table[level].max_lazy; | |
447 | s->good_match = configuration_table[level].good_length; | |
448 | s->nice_match = configuration_table[level].nice_length; | |
449 | s->max_chain_length = configuration_table[level].max_chain; | |
d4286ec4 PM |
450 | } |
451 | s->strategy = strategy; | |
452 | return err; | |
453 | } | |
454 | ||
cd426074 WD |
455 | /* ========================================================================= */ |
456 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) | |
457 | z_streamp strm; | |
458 | int good_length; | |
459 | int max_lazy; | |
460 | int nice_length; | |
461 | int max_chain; | |
462 | { | |
463 | deflate_state *s; | |
464 | ||
465 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
466 | s = strm->state; | |
467 | s->good_match = good_length; | |
468 | s->max_lazy_match = max_lazy; | |
469 | s->nice_match = nice_length; | |
470 | s->max_chain_length = max_chain; | |
471 | return Z_OK; | |
472 | } | |
473 | ||
1e1cf689 WD |
474 | /* ========================================================================= |
475 | * For the default windowBits of 15 and memLevel of 8, this function returns | |
476 | * a close to exact, as well as small, upper bound on the compressed size. | |
477 | * They are coded as constants here for a reason--if the #define's are | |
478 | * changed, then this function needs to be changed as well. The return | |
479 | * value for 15 and 8 only works for those exact settings. | |
480 | * | |
481 | * For any setting other than those defaults for windowBits and memLevel, | |
482 | * the value returned is a conservative worst case for the maximum expansion | |
483 | * resulting from using fixed blocks instead of stored blocks, which deflate | |
484 | * can emit on compressed data for some combinations of the parameters. | |
485 | * | |
486 | * This function could be more sophisticated to provide closer upper bounds | |
487 | * for every combination of windowBits and memLevel, as well as wrap. | |
488 | * But even the conservative upper bound of about 14% expansion does not | |
489 | * seem onerous for output buffer allocation. | |
490 | */ | |
491 | uLong ZEXPORT deflateBound(strm, sourceLen) | |
492 | z_streamp strm; | |
493 | uLong sourceLen; | |
494 | { | |
495 | deflate_state *s; | |
496 | uLong destLen; | |
497 | ||
498 | /* conservative upper bound */ | |
499 | destLen = sourceLen + | |
500 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; | |
501 | ||
502 | /* if can't get parameters, return conservative bound */ | |
503 | if (strm == Z_NULL || strm->state == Z_NULL) | |
504 | return destLen; | |
505 | ||
506 | /* if not default parameters, return conservative bound */ | |
507 | s = strm->state; | |
508 | if (s->w_bits != 15 || s->hash_bits != 8 + 7) | |
509 | return destLen; | |
510 | ||
511 | /* default settings: return tight bound for that case */ | |
512 | return compressBound(sourceLen); | |
513 | } | |
514 | ||
d4286ec4 PM |
515 | /* ========================================================================= |
516 | * Put a short in the pending buffer. The 16-bit value is put in MSB order. | |
517 | * IN assertion: the stream state is correct and there is enough room in | |
518 | * pending_buf. | |
519 | */ | |
520 | local void putShortMSB (s, b) | |
521 | deflate_state *s; | |
522 | uInt b; | |
523 | { | |
524 | put_byte(s, (Byte)(b >> 8)); | |
525 | put_byte(s, (Byte)(b & 0xff)); | |
1e1cf689 | 526 | } |
d4286ec4 PM |
527 | |
528 | /* ========================================================================= | |
529 | * Flush as much pending output as possible. All deflate() output goes | |
530 | * through this function so some applications may wish to modify it | |
531 | * to avoid allocating a large strm->next_out buffer and copying into it. | |
12febd80 | 532 | * (See also read_buf()). |
d4286ec4 PM |
533 | */ |
534 | local void flush_pending(strm) | |
535 | z_streamp strm; | |
536 | { | |
537 | unsigned len = strm->state->pending; | |
538 | ||
539 | if (len > strm->avail_out) len = strm->avail_out; | |
540 | if (len == 0) return; | |
541 | ||
542 | zmemcpy(strm->next_out, strm->state->pending_out, len); | |
543 | strm->next_out += len; | |
544 | strm->state->pending_out += len; | |
545 | strm->total_out += len; | |
546 | strm->avail_out -= len; | |
547 | strm->state->pending -= len; | |
548 | if (strm->state->pending == 0) { | |
549 | strm->state->pending_out = strm->state->pending_buf; | |
550 | } | |
551 | } | |
552 | ||
553 | /* ========================================================================= */ | |
554 | int ZEXPORT deflate (strm, flush) | |
555 | z_streamp strm; | |
556 | int flush; | |
557 | { | |
558 | int old_flush; /* value of flush param for previous deflate call */ | |
559 | deflate_state *s; | |
560 | ||
561 | if (strm == Z_NULL || strm->state == Z_NULL || | |
1e1cf689 | 562 | flush > Z_INSERT_ONLY || flush < 0) { |
d4286ec4 PM |
563 | return Z_STREAM_ERROR; |
564 | } | |
565 | s = strm->state; | |
566 | ||
567 | if (strm->next_out == Z_NULL || | |
568 | (strm->next_in == Z_NULL && strm->avail_in != 0) || | |
1e1cf689 | 569 | (s->status == FINISH_STATE && flush != Z_FINISH)) { |
d4286ec4 PM |
570 | ERR_RETURN(strm, Z_STREAM_ERROR); |
571 | } | |
572 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); | |
573 | ||
574 | s->strm = strm; /* just in case */ | |
575 | old_flush = s->last_flush; | |
576 | s->last_flush = flush; | |
577 | ||
1e1cf689 | 578 | /* Write the header */ |
d4286ec4 | 579 | if (s->status == INIT_STATE) { |
1e1cf689 WD |
580 | #ifdef GZIP |
581 | if (s->wrap == 2) { | |
cd426074 | 582 | strm->adler = crc32(0L, Z_NULL, 0); |
1e1cf689 WD |
583 | put_byte(s, 31); |
584 | put_byte(s, 139); | |
585 | put_byte(s, 8); | |
cd426074 WD |
586 | if (s->gzhead == NULL) { |
587 | put_byte(s, 0); | |
588 | put_byte(s, 0); | |
589 | put_byte(s, 0); | |
590 | put_byte(s, 0); | |
591 | put_byte(s, 0); | |
592 | put_byte(s, s->level == 9 ? 2 : | |
593 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
594 | 4 : 0)); | |
595 | put_byte(s, OS_CODE); | |
596 | s->status = BUSY_STATE; | |
597 | } | |
598 | else { | |
599 | put_byte(s, (s->gzhead->text ? 1 : 0) + | |
600 | (s->gzhead->hcrc ? 2 : 0) + | |
601 | (s->gzhead->extra == Z_NULL ? 0 : 4) + | |
602 | (s->gzhead->name == Z_NULL ? 0 : 8) + | |
603 | (s->gzhead->comment == Z_NULL ? 0 : 16) | |
604 | ); | |
605 | put_byte(s, (Byte)(s->gzhead->time & 0xff)); | |
606 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); | |
607 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); | |
608 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); | |
609 | put_byte(s, s->level == 9 ? 2 : | |
610 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
611 | 4 : 0)); | |
612 | put_byte(s, s->gzhead->os & 0xff); | |
613 | if (s->gzhead->extra != NULL) { | |
614 | put_byte(s, s->gzhead->extra_len & 0xff); | |
615 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); | |
616 | } | |
617 | if (s->gzhead->hcrc) | |
618 | strm->adler = crc32(strm->adler, s->pending_buf, | |
619 | s->pending); | |
620 | s->gzindex = 0; | |
621 | s->status = EXTRA_STATE; | |
622 | } | |
1e1cf689 WD |
623 | } |
624 | else | |
625 | #endif | |
626 | { | |
627 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; | |
628 | uInt level_flags; | |
629 | ||
630 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) | |
631 | level_flags = 0; | |
632 | else if (s->level < 6) | |
633 | level_flags = 1; | |
634 | else if (s->level == 6) | |
635 | level_flags = 2; | |
636 | else | |
637 | level_flags = 3; | |
638 | header |= (level_flags << 6); | |
639 | if (s->strstart != 0) header |= PRESET_DICT; | |
640 | header += 31 - (header % 31); | |
641 | ||
642 | s->status = BUSY_STATE; | |
643 | putShortMSB(s, header); | |
644 | ||
645 | /* Save the adler32 of the preset dictionary: */ | |
646 | if (s->strstart != 0) { | |
647 | putShortMSB(s, (uInt)(strm->adler >> 16)); | |
648 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
649 | } | |
650 | strm->adler = adler32(0L, Z_NULL, 0); | |
651 | } | |
d4286ec4 | 652 | } |
cd426074 WD |
653 | #ifdef GZIP |
654 | if (s->status == EXTRA_STATE) { | |
655 | if (s->gzhead->extra != NULL) { | |
656 | uInt beg = s->pending; /* start of bytes to update crc */ | |
657 | ||
658 | while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { | |
659 | if (s->pending == s->pending_buf_size) { | |
660 | if (s->gzhead->hcrc && s->pending > beg) | |
661 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
662 | s->pending - beg); | |
663 | flush_pending(strm); | |
664 | beg = s->pending; | |
665 | if (s->pending == s->pending_buf_size) | |
666 | break; | |
667 | } | |
668 | put_byte(s, s->gzhead->extra[s->gzindex]); | |
669 | s->gzindex++; | |
670 | } | |
671 | if (s->gzhead->hcrc && s->pending > beg) | |
672 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
673 | s->pending - beg); | |
674 | if (s->gzindex == s->gzhead->extra_len) { | |
675 | s->gzindex = 0; | |
676 | s->status = NAME_STATE; | |
677 | } | |
678 | } | |
679 | else | |
680 | s->status = NAME_STATE; | |
681 | } | |
682 | if (s->status == NAME_STATE) { | |
683 | if (s->gzhead->name != NULL) { | |
684 | uInt beg = s->pending; /* start of bytes to update crc */ | |
685 | int val; | |
686 | ||
687 | do { | |
688 | if (s->pending == s->pending_buf_size) { | |
689 | if (s->gzhead->hcrc && s->pending > beg) | |
690 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
691 | s->pending - beg); | |
692 | flush_pending(strm); | |
693 | beg = s->pending; | |
694 | if (s->pending == s->pending_buf_size) { | |
695 | val = 1; | |
696 | break; | |
697 | } | |
698 | } | |
699 | val = s->gzhead->name[s->gzindex++]; | |
700 | put_byte(s, val); | |
701 | } while (val != 0); | |
702 | if (s->gzhead->hcrc && s->pending > beg) | |
703 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
704 | s->pending - beg); | |
705 | if (val == 0) { | |
706 | s->gzindex = 0; | |
707 | s->status = COMMENT_STATE; | |
708 | } | |
709 | } | |
710 | else | |
711 | s->status = COMMENT_STATE; | |
712 | } | |
713 | if (s->status == COMMENT_STATE) { | |
714 | if (s->gzhead->comment != NULL) { | |
715 | uInt beg = s->pending; /* start of bytes to update crc */ | |
716 | int val; | |
717 | ||
718 | do { | |
719 | if (s->pending == s->pending_buf_size) { | |
720 | if (s->gzhead->hcrc && s->pending > beg) | |
721 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
722 | s->pending - beg); | |
723 | flush_pending(strm); | |
724 | beg = s->pending; | |
725 | if (s->pending == s->pending_buf_size) { | |
726 | val = 1; | |
727 | break; | |
728 | } | |
729 | } | |
730 | val = s->gzhead->comment[s->gzindex++]; | |
731 | put_byte(s, val); | |
732 | } while (val != 0); | |
733 | if (s->gzhead->hcrc && s->pending > beg) | |
734 | strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
735 | s->pending - beg); | |
736 | if (val == 0) | |
737 | s->status = HCRC_STATE; | |
738 | } | |
739 | else | |
740 | s->status = HCRC_STATE; | |
741 | } | |
742 | if (s->status == HCRC_STATE) { | |
743 | if (s->gzhead->hcrc) { | |
744 | if (s->pending + 2 > s->pending_buf_size) | |
745 | flush_pending(strm); | |
746 | if (s->pending + 2 <= s->pending_buf_size) { | |
747 | put_byte(s, (Byte)(strm->adler & 0xff)); | |
748 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
749 | strm->adler = crc32(0L, Z_NULL, 0); | |
750 | s->status = BUSY_STATE; | |
751 | } | |
752 | } | |
753 | else | |
754 | s->status = BUSY_STATE; | |
755 | } | |
756 | #endif | |
d4286ec4 PM |
757 | |
758 | /* Flush as much pending output as possible */ | |
759 | if (s->pending != 0) { | |
760 | flush_pending(strm); | |
761 | if (strm->avail_out == 0) { | |
1e1cf689 WD |
762 | /* Since avail_out is 0, deflate will be called again with |
763 | * more output space, but possibly with both pending and | |
764 | * avail_in equal to zero. There won't be anything to do, | |
765 | * but this is not an error situation so make sure we | |
766 | * return OK instead of BUF_ERROR at next call of deflate: | |
d4286ec4 | 767 | */ |
1e1cf689 WD |
768 | s->last_flush = -1; |
769 | return Z_OK; | |
770 | } | |
d4286ec4 PM |
771 | |
772 | /* Make sure there is something to do and avoid duplicate consecutive | |
773 | * flushes. For repeated and useless calls with Z_FINISH, we keep | |
1e1cf689 | 774 | * returning Z_STREAM_END instead of Z_BUF_ERROR. |
d4286ec4 PM |
775 | */ |
776 | } else if (strm->avail_in == 0 && flush <= old_flush && | |
1e1cf689 | 777 | flush != Z_FINISH) { |
d4286ec4 PM |
778 | ERR_RETURN(strm, Z_BUF_ERROR); |
779 | } | |
780 | ||
781 | /* User must not provide more input after the first FINISH: */ | |
782 | if (s->status == FINISH_STATE && strm->avail_in != 0) { | |
783 | ERR_RETURN(strm, Z_BUF_ERROR); | |
784 | } | |
785 | ||
786 | /* Start a new block or continue the current one. | |
787 | */ | |
788 | if (strm->avail_in != 0 || s->lookahead != 0 || | |
789 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { | |
790 | block_state bstate; | |
791 | ||
1e1cf689 | 792 | bstate = (*(configuration_table[s->level].func))(s, flush); |
d4286ec4 PM |
793 | |
794 | if (bstate == finish_started || bstate == finish_done) { | |
795 | s->status = FINISH_STATE; | |
796 | } | |
797 | if (bstate == need_more || bstate == finish_started) { | |
1e1cf689 WD |
798 | if (strm->avail_out == 0) { |
799 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ | |
800 | } | |
801 | return Z_OK; | |
802 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call | |
803 | * of deflate should use the same flush parameter to make sure | |
804 | * that the flush is complete. So we don't have to output an | |
805 | * empty block here, this will be done at next call. This also | |
806 | * ensures that for a very small output buffer, we emit at most | |
807 | * one empty block. | |
808 | */ | |
809 | } | |
d4286ec4 PM |
810 | if (bstate == block_done) { |
811 | if (flush == Z_PARTIAL_FLUSH) { | |
812 | _tr_align(s); | |
813 | } else { /* FULL_FLUSH or SYNC_FLUSH */ | |
814 | _tr_stored_block(s, (char*)0, 0L, 0); | |
815 | /* For a full flush, this empty block will be recognized | |
816 | * as a special marker by inflate_sync(). | |
817 | */ | |
818 | if (flush == Z_FULL_FLUSH) { | |
819 | CLEAR_HASH(s); /* forget history */ | |
820 | } | |
821 | } | |
822 | flush_pending(strm); | |
1e1cf689 WD |
823 | if (strm->avail_out == 0) { |
824 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ | |
825 | return Z_OK; | |
826 | } | |
d4286ec4 PM |
827 | } |
828 | } | |
829 | Assert(strm->avail_out > 0, "bug2"); | |
830 | ||
831 | if (flush != Z_FINISH) return Z_OK; | |
1e1cf689 WD |
832 | if (s->wrap <= 0) return Z_STREAM_END; |
833 | ||
834 | /* Write the trailer */ | |
835 | #ifdef GZIP | |
836 | if (s->wrap == 2) { | |
837 | put_byte(s, (Byte)(strm->adler & 0xff)); | |
838 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
839 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); | |
840 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); | |
841 | put_byte(s, (Byte)(strm->total_in & 0xff)); | |
842 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); | |
843 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); | |
844 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); | |
845 | } | |
846 | else | |
847 | #endif | |
848 | { | |
849 | putShortMSB(s, (uInt)(strm->adler >> 16)); | |
850 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
851 | } | |
d4286ec4 PM |
852 | flush_pending(strm); |
853 | /* If avail_out is zero, the application will call deflate again | |
854 | * to flush the rest. | |
855 | */ | |
1e1cf689 | 856 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ |
d4286ec4 PM |
857 | return s->pending != 0 ? Z_OK : Z_STREAM_END; |
858 | } | |
859 | ||
860 | /* ========================================================================= */ | |
861 | int ZEXPORT deflateEnd (strm) | |
862 | z_streamp strm; | |
863 | { | |
864 | int status; | |
865 | ||
866 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
867 | ||
868 | status = strm->state->status; | |
cd426074 WD |
869 | if (status != INIT_STATE && |
870 | status != EXTRA_STATE && | |
871 | status != NAME_STATE && | |
872 | status != COMMENT_STATE && | |
873 | status != HCRC_STATE && | |
874 | status != BUSY_STATE && | |
1e1cf689 | 875 | status != FINISH_STATE) { |
d4286ec4 PM |
876 | return Z_STREAM_ERROR; |
877 | } | |
878 | ||
879 | /* Deallocate in reverse order of allocations: */ | |
880 | TRY_FREE(strm, strm->state->pending_buf); | |
881 | TRY_FREE(strm, strm->state->head); | |
882 | TRY_FREE(strm, strm->state->prev); | |
883 | TRY_FREE(strm, strm->state->window); | |
884 | ||
885 | ZFREE(strm, strm->state); | |
886 | strm->state = Z_NULL; | |
887 | ||
888 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; | |
889 | } | |
890 | ||
891 | /* ========================================================================= | |
892 | * Copy the source state to the destination state. | |
893 | * To simplify the source, this is not supported for 16-bit MSDOS (which | |
894 | * doesn't have enough memory anyway to duplicate compression states). | |
895 | */ | |
896 | int ZEXPORT deflateCopy (dest, source) | |
897 | z_streamp dest; | |
898 | z_streamp source; | |
899 | { | |
900 | #ifdef MAXSEG_64K | |
901 | return Z_STREAM_ERROR; | |
902 | #else | |
903 | deflate_state *ds; | |
904 | deflate_state *ss; | |
905 | ushf *overlay; | |
906 | ||
d4286ec4 | 907 | |
06b91d8e | 908 | if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { |
d4286ec4 PM |
909 | return Z_STREAM_ERROR; |
910 | } | |
06b91d8e MP |
911 | |
912 | ss = source->state; | |
913 | ||
cd426074 | 914 | zmemcpy(dest, source, sizeof(z_stream)); |
d4286ec4 PM |
915 | |
916 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); | |
917 | if (ds == Z_NULL) return Z_MEM_ERROR; | |
918 | dest->state = (struct internal_state FAR *) ds; | |
cd426074 | 919 | zmemcpy(ds, ss, sizeof(deflate_state)); |
d4286ec4 PM |
920 | ds->strm = dest; |
921 | ||
922 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); | |
923 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); | |
924 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); | |
925 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); | |
926 | ds->pending_buf = (uchf *) overlay; | |
927 | ||
928 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || | |
929 | ds->pending_buf == Z_NULL) { | |
930 | deflateEnd (dest); | |
931 | return Z_MEM_ERROR; | |
932 | } | |
933 | /* following zmemcpy do not work for 16-bit MSDOS */ | |
934 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); | |
935 | zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); | |
936 | zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); | |
937 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); | |
938 | ||
939 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); | |
940 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); | |
941 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; | |
942 | ||
943 | ds->l_desc.dyn_tree = ds->dyn_ltree; | |
944 | ds->d_desc.dyn_tree = ds->dyn_dtree; | |
945 | ds->bl_desc.dyn_tree = ds->bl_tree; | |
946 | ||
947 | return Z_OK; | |
1e1cf689 | 948 | #endif /* MAXSEG_64K */ |
d4286ec4 PM |
949 | } |
950 | ||
951 | /* =========================================================================== | |
952 | * Read a new buffer from the current input stream, update the adler32 | |
953 | * and total number of bytes read. All deflate() input goes through | |
954 | * this function so some applications may wish to modify it to avoid | |
955 | * allocating a large strm->next_in buffer and copying from it. | |
956 | * (See also flush_pending()). | |
957 | */ | |
12febd80 | 958 | local int read_buf(strm, buf, size) |
d4286ec4 PM |
959 | z_streamp strm; |
960 | Bytef *buf; | |
961 | unsigned size; | |
962 | { | |
963 | unsigned len = strm->avail_in; | |
964 | ||
965 | if (len > size) len = size; | |
966 | if (len == 0) return 0; | |
967 | ||
968 | strm->avail_in -= len; | |
969 | ||
1e1cf689 | 970 | if (strm->state->wrap == 1) { |
d4286ec4 PM |
971 | strm->adler = adler32(strm->adler, strm->next_in, len); |
972 | } | |
1e1cf689 WD |
973 | #ifdef GZIP |
974 | else if (strm->state->wrap == 2) { | |
975 | strm->adler = crc32(strm->adler, strm->next_in, len); | |
976 | } | |
977 | #endif | |
d4286ec4 PM |
978 | zmemcpy(buf, strm->next_in, len); |
979 | strm->next_in += len; | |
980 | strm->total_in += len; | |
981 | ||
982 | return (int)len; | |
983 | } | |
984 | ||
985 | /* =========================================================================== | |
986 | * Initialize the "longest match" routines for a new zlib stream | |
987 | */ | |
988 | local void lm_init (s) | |
989 | deflate_state *s; | |
990 | { | |
991 | s->window_size = (ulg)2L*s->w_size; | |
992 | ||
993 | CLEAR_HASH(s); | |
994 | ||
995 | /* Set the default configuration parameters: | |
996 | */ | |
997 | s->max_lazy_match = configuration_table[s->level].max_lazy; | |
998 | s->good_match = configuration_table[s->level].good_length; | |
999 | s->nice_match = configuration_table[s->level].nice_length; | |
1000 | s->max_chain_length = configuration_table[s->level].max_chain; | |
1001 | ||
1002 | s->strstart = 0; | |
1003 | s->block_start = 0L; | |
1004 | s->lookahead = 0; | |
1005 | s->match_length = s->prev_length = MIN_MATCH-1; | |
1006 | s->match_available = 0; | |
1007 | s->ins_h = 0; | |
cd426074 | 1008 | #ifndef FASTEST |
d4286ec4 PM |
1009 | #ifdef ASMV |
1010 | match_init(); /* initialize the asm code */ | |
1011 | #endif | |
cd426074 | 1012 | #endif |
d4286ec4 PM |
1013 | } |
1014 | ||
1e1cf689 | 1015 | #ifndef FASTEST |
d4286ec4 PM |
1016 | /* =========================================================================== |
1017 | * Set match_start to the longest match starting at the given string and | |
1018 | * return its length. Matches shorter or equal to prev_length are discarded, | |
1019 | * in which case the result is equal to prev_length and match_start is | |
1020 | * garbage. | |
1021 | * IN assertions: cur_match is the head of the hash chain for the current | |
1022 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | |
1023 | * OUT assertion: the match length is not greater than s->lookahead. | |
1024 | */ | |
1025 | #ifndef ASMV | |
1026 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or | |
1027 | * match.S. The code will be functionally equivalent. | |
1028 | */ | |
d4286ec4 PM |
1029 | local uInt longest_match(s, cur_match) |
1030 | deflate_state *s; | |
1031 | IPos cur_match; /* current match */ | |
1032 | { | |
1033 | unsigned chain_length = s->max_chain_length;/* max hash chain length */ | |
1034 | register Bytef *scan = s->window + s->strstart; /* current string */ | |
1035 | register Bytef *match; /* matched string */ | |
1036 | register int len; /* length of current match */ | |
1037 | int best_len = s->prev_length; /* best match length so far */ | |
1038 | int nice_match = s->nice_match; /* stop if match long enough */ | |
1039 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | |
1040 | s->strstart - (IPos)MAX_DIST(s) : NIL; | |
1041 | /* Stop when cur_match becomes <= limit. To simplify the code, | |
1042 | * we prevent matches with the string of window index 0. | |
1043 | */ | |
1044 | Posf *prev = s->prev; | |
1045 | uInt wmask = s->w_mask; | |
1046 | ||
1047 | #ifdef UNALIGNED_OK | |
1048 | /* Compare two bytes at a time. Note: this is not always beneficial. | |
1049 | * Try with and without -DUNALIGNED_OK to check. | |
1050 | */ | |
1051 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; | |
1052 | register ush scan_start = *(ushf*)scan; | |
1053 | register ush scan_end = *(ushf*)(scan+best_len-1); | |
1054 | #else | |
1055 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1056 | register Byte scan_end1 = scan[best_len-1]; | |
1057 | register Byte scan_end = scan[best_len]; | |
1058 | #endif | |
1059 | ||
1060 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1061 | * It is easy to get rid of this optimization if necessary. | |
1062 | */ | |
1063 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1064 | ||
1065 | /* Do not waste too much time if we already have a good match: */ | |
1066 | if (s->prev_length >= s->good_match) { | |
1067 | chain_length >>= 2; | |
1068 | } | |
1069 | /* Do not look for matches beyond the end of the input. This is necessary | |
1070 | * to make deflate deterministic. | |
1071 | */ | |
1072 | if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; | |
1073 | ||
1074 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1075 | ||
1076 | do { | |
1077 | Assert(cur_match < s->strstart, "no future"); | |
1078 | match = s->window + cur_match; | |
1079 | ||
1080 | /* Skip to next match if the match length cannot increase | |
cd426074 WD |
1081 | * or if the match length is less than 2. Note that the checks below |
1082 | * for insufficient lookahead only occur occasionally for performance | |
1083 | * reasons. Therefore uninitialized memory will be accessed, and | |
1084 | * conditional jumps will be made that depend on those values. | |
1085 | * However the length of the match is limited to the lookahead, so | |
1086 | * the output of deflate is not affected by the uninitialized values. | |
d4286ec4 PM |
1087 | */ |
1088 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) | |
1089 | /* This code assumes sizeof(unsigned short) == 2. Do not use | |
1090 | * UNALIGNED_OK if your compiler uses a different size. | |
1091 | */ | |
1092 | if (*(ushf*)(match+best_len-1) != scan_end || | |
1093 | *(ushf*)match != scan_start) continue; | |
1094 | ||
1095 | /* It is not necessary to compare scan[2] and match[2] since they are | |
1096 | * always equal when the other bytes match, given that the hash keys | |
1097 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at | |
1098 | * strstart+3, +5, ... up to strstart+257. We check for insufficient | |
1099 | * lookahead only every 4th comparison; the 128th check will be made | |
1100 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is | |
1101 | * necessary to put more guard bytes at the end of the window, or | |
1102 | * to check more often for insufficient lookahead. | |
1103 | */ | |
1104 | Assert(scan[2] == match[2], "scan[2]?"); | |
1105 | scan++, match++; | |
1106 | do { | |
1107 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1108 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1109 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1110 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1111 | scan < strend); | |
1112 | /* The funny "do {}" generates better code on most compilers */ | |
1113 | ||
1114 | /* Here, scan <= window+strstart+257 */ | |
1115 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1116 | if (*scan == *match) scan++; | |
1117 | ||
1118 | len = (MAX_MATCH - 1) - (int)(strend-scan); | |
1119 | scan = strend - (MAX_MATCH-1); | |
1120 | ||
1121 | #else /* UNALIGNED_OK */ | |
1122 | ||
1123 | if (match[best_len] != scan_end || | |
1124 | match[best_len-1] != scan_end1 || | |
1125 | *match != *scan || | |
1126 | *++match != scan[1]) continue; | |
1127 | ||
1128 | /* The check at best_len-1 can be removed because it will be made | |
1129 | * again later. (This heuristic is not always a win.) | |
1130 | * It is not necessary to compare scan[2] and match[2] since they | |
1131 | * are always equal when the other bytes match, given that | |
1132 | * the hash keys are equal and that HASH_BITS >= 8. | |
1133 | */ | |
1134 | scan += 2, match++; | |
1135 | Assert(*scan == *match, "match[2]?"); | |
1136 | ||
1137 | /* We check for insufficient lookahead only every 8th comparison; | |
1138 | * the 256th check will be made at strstart+258. | |
1139 | */ | |
1140 | do { | |
1141 | } while (*++scan == *++match && *++scan == *++match && | |
1142 | *++scan == *++match && *++scan == *++match && | |
1143 | *++scan == *++match && *++scan == *++match && | |
1144 | *++scan == *++match && *++scan == *++match && | |
1145 | scan < strend); | |
1146 | ||
1147 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1148 | ||
1149 | len = MAX_MATCH - (int)(strend - scan); | |
1150 | scan = strend - MAX_MATCH; | |
1151 | ||
1152 | #endif /* UNALIGNED_OK */ | |
1153 | ||
1154 | if (len > best_len) { | |
1155 | s->match_start = cur_match; | |
1156 | best_len = len; | |
1157 | if (len >= nice_match) break; | |
1158 | #ifdef UNALIGNED_OK | |
1159 | scan_end = *(ushf*)(scan+best_len-1); | |
1160 | #else | |
1161 | scan_end1 = scan[best_len-1]; | |
1162 | scan_end = scan[best_len]; | |
1163 | #endif | |
1164 | } | |
1165 | } while ((cur_match = prev[cur_match & wmask]) > limit | |
1166 | && --chain_length != 0); | |
1167 | ||
1168 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | |
1169 | return s->lookahead; | |
1170 | } | |
1e1cf689 WD |
1171 | #endif /* ASMV */ |
1172 | #endif /* FASTEST */ | |
d4286ec4 | 1173 | |
d4286ec4 | 1174 | /* --------------------------------------------------------------------------- |
1e1cf689 | 1175 | * Optimized version for level == 1 or strategy == Z_RLE only |
d4286ec4 | 1176 | */ |
1e1cf689 | 1177 | local uInt longest_match_fast(s, cur_match) |
d4286ec4 PM |
1178 | deflate_state *s; |
1179 | IPos cur_match; /* current match */ | |
1180 | { | |
1181 | register Bytef *scan = s->window + s->strstart; /* current string */ | |
1182 | register Bytef *match; /* matched string */ | |
1183 | register int len; /* length of current match */ | |
1184 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1185 | ||
1186 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1187 | * It is easy to get rid of this optimization if necessary. | |
1188 | */ | |
1189 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1190 | ||
1191 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1192 | ||
1193 | Assert(cur_match < s->strstart, "no future"); | |
1194 | ||
1195 | match = s->window + cur_match; | |
1196 | ||
1197 | /* Return failure if the match length is less than 2: | |
1198 | */ | |
1199 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; | |
1200 | ||
1201 | /* The check at best_len-1 can be removed because it will be made | |
1202 | * again later. (This heuristic is not always a win.) | |
1203 | * It is not necessary to compare scan[2] and match[2] since they | |
1204 | * are always equal when the other bytes match, given that | |
1205 | * the hash keys are equal and that HASH_BITS >= 8. | |
1206 | */ | |
1207 | scan += 2, match += 2; | |
1208 | Assert(*scan == *match, "match[2]?"); | |
1209 | ||
1210 | /* We check for insufficient lookahead only every 8th comparison; | |
1211 | * the 256th check will be made at strstart+258. | |
1212 | */ | |
1213 | do { | |
1214 | } while (*++scan == *++match && *++scan == *++match && | |
1e1cf689 WD |
1215 | *++scan == *++match && *++scan == *++match && |
1216 | *++scan == *++match && *++scan == *++match && | |
1217 | *++scan == *++match && *++scan == *++match && | |
1218 | scan < strend); | |
d4286ec4 PM |
1219 | |
1220 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1221 | ||
1222 | len = MAX_MATCH - (int)(strend - scan); | |
1223 | ||
1224 | if (len < MIN_MATCH) return MIN_MATCH - 1; | |
1225 | ||
1226 | s->match_start = cur_match; | |
1e1cf689 | 1227 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; |
d4286ec4 | 1228 | } |
d4286ec4 PM |
1229 | |
1230 | #ifdef DEBUG | |
1231 | /* =========================================================================== | |
1232 | * Check that the match at match_start is indeed a match. | |
1233 | */ | |
1234 | local void check_match(s, start, match, length) | |
1235 | deflate_state *s; | |
1236 | IPos start, match; | |
1237 | int length; | |
1238 | { | |
1239 | /* check that the match is indeed a match */ | |
1240 | if (zmemcmp(s->window + match, | |
1241 | s->window + start, length) != EQUAL) { | |
1242 | fprintf(stderr, " start %u, match %u, length %d\n", | |
1e1cf689 | 1243 | start, match, length); |
d4286ec4 | 1244 | do { |
1e1cf689 WD |
1245 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); |
1246 | } while (--length != 0); | |
d4286ec4 PM |
1247 | z_error("invalid match"); |
1248 | } | |
1249 | if (z_verbose > 1) { | |
1250 | fprintf(stderr,"\\[%d,%d]", start-match, length); | |
1251 | do { putc(s->window[start++], stderr); } while (--length != 0); | |
1252 | } | |
1253 | } | |
1254 | #else | |
1255 | # define check_match(s, start, match, length) | |
1e1cf689 | 1256 | #endif /* DEBUG */ |
d4286ec4 PM |
1257 | |
1258 | /* =========================================================================== | |
1259 | * Fill the window when the lookahead becomes insufficient. | |
1260 | * Updates strstart and lookahead. | |
1261 | * | |
1262 | * IN assertion: lookahead < MIN_LOOKAHEAD | |
1263 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD | |
1264 | * At least one byte has been read, or avail_in == 0; reads are | |
1265 | * performed for at least two bytes (required for the zip translate_eol | |
1266 | * option -- not supported here). | |
1267 | */ | |
1268 | local void fill_window(s) | |
1269 | deflate_state *s; | |
1270 | { | |
1271 | register unsigned n, m; | |
1272 | register Posf *p; | |
1273 | unsigned more; /* Amount of free space at the end of the window. */ | |
1274 | uInt wsize = s->w_size; | |
1275 | ||
1276 | do { | |
1277 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); | |
1278 | ||
1279 | /* Deal with !@#$% 64K limit: */ | |
1e1cf689 WD |
1280 | if (sizeof(int) <= 2) { |
1281 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) { | |
1282 | more = wsize; | |
d4286ec4 | 1283 | |
1e1cf689 WD |
1284 | } else if (more == (unsigned)(-1)) { |
1285 | /* Very unlikely, but possible on 16 bit machine if | |
1286 | * strstart == 0 && lookahead == 1 (input done a byte at time) | |
1287 | */ | |
1288 | more--; | |
1289 | } | |
1290 | } | |
d4286ec4 PM |
1291 | |
1292 | /* If the window is almost full and there is insufficient lookahead, | |
1293 | * move the upper half to the lower one to make room in the upper half. | |
1294 | */ | |
1e1cf689 | 1295 | if (s->strstart >= wsize+MAX_DIST(s)) { |
d4286ec4 PM |
1296 | |
1297 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize); | |
1298 | s->match_start -= wsize; | |
1299 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ | |
1300 | s->block_start -= (long) wsize; | |
1301 | ||
1302 | /* Slide the hash table (could be avoided with 32 bit values | |
1303 | at the expense of memory usage). We slide even when level == 0 | |
1304 | to keep the hash table consistent if we switch back to level > 0 | |
1305 | later. (Using level 0 permanently is not an optimal usage of | |
1306 | zlib, so we don't care about this pathological case.) | |
1307 | */ | |
cd426074 | 1308 | /* %%% avoid this when Z_RLE */ |
1e1cf689 WD |
1309 | n = s->hash_size; |
1310 | p = &s->head[n]; | |
1311 | do { | |
1312 | m = *--p; | |
1313 | *p = (Pos)(m >= wsize ? m-wsize : NIL); | |
1314 | } while (--n); | |
1315 | ||
1316 | n = wsize; | |
d4286ec4 | 1317 | #ifndef FASTEST |
1e1cf689 WD |
1318 | p = &s->prev[n]; |
1319 | do { | |
1320 | m = *--p; | |
1321 | *p = (Pos)(m >= wsize ? m-wsize : NIL); | |
1322 | /* If n is not on any hash chain, prev[n] is garbage but | |
1323 | * its value will never be used. | |
1324 | */ | |
1325 | } while (--n); | |
d4286ec4 PM |
1326 | #endif |
1327 | more += wsize; | |
1328 | } | |
1329 | if (s->strm->avail_in == 0) return; | |
1330 | ||
1331 | /* If there was no sliding: | |
1332 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && | |
1333 | * more == window_size - lookahead - strstart | |
1334 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) | |
1335 | * => more >= window_size - 2*WSIZE + 2 | |
1336 | * In the BIG_MEM or MMAP case (not yet supported), | |
1337 | * window_size == input_size + MIN_LOOKAHEAD && | |
1338 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. | |
1339 | * Otherwise, window_size == 2*WSIZE so more >= 2. | |
1340 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2. | |
1341 | */ | |
1342 | Assert(more >= 2, "more < 2"); | |
1343 | ||
12febd80 | 1344 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); |
d4286ec4 PM |
1345 | s->lookahead += n; |
1346 | ||
1347 | /* Initialize the hash value now that we have some input: */ | |
1348 | if (s->lookahead >= MIN_MATCH) { | |
1349 | s->ins_h = s->window[s->strstart]; | |
1350 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
1351 | #if MIN_MATCH != 3 | |
1352 | Call UPDATE_HASH() MIN_MATCH-3 more times | |
1353 | #endif | |
1354 | } | |
1355 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, | |
1356 | * but this is not important since only literal bytes will be emitted. | |
1357 | */ | |
1358 | ||
1359 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); | |
1360 | } | |
1361 | ||
1362 | /* =========================================================================== | |
1363 | * Flush the current block, with given end-of-file flag. | |
1364 | * IN assertion: strstart is set to the end of the current match. | |
1365 | */ | |
1366 | #define FLUSH_BLOCK_ONLY(s, eof) { \ | |
1367 | _tr_flush_block(s, (s->block_start >= 0L ? \ | |
1368 | (charf *)&s->window[(unsigned)s->block_start] : \ | |
1369 | (charf *)Z_NULL), \ | |
1e1cf689 WD |
1370 | (ulg)((long)s->strstart - s->block_start), \ |
1371 | (eof)); \ | |
d4286ec4 PM |
1372 | s->block_start = s->strstart; \ |
1373 | flush_pending(s->strm); \ | |
1374 | Tracev((stderr,"[FLUSH]")); \ | |
1375 | } | |
1376 | ||
1377 | /* Same but force premature exit if necessary. */ | |
1378 | #define FLUSH_BLOCK(s, eof) { \ | |
1379 | FLUSH_BLOCK_ONLY(s, eof); \ | |
1380 | if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ | |
1381 | } | |
1382 | ||
1383 | /* =========================================================================== | |
1384 | * Copy without compression as much as possible from the input stream, return | |
1385 | * the current block state. | |
1386 | * This function does not insert new strings in the dictionary since | |
1387 | * uncompressible data is probably not useful. This function is used | |
1388 | * only for the level=0 compression option. | |
1389 | * NOTE: this function should be optimized to avoid extra copying from | |
1390 | * window to pending_buf. | |
1391 | */ | |
1392 | local block_state deflate_stored(s, flush) | |
1393 | deflate_state *s; | |
1394 | int flush; | |
1395 | { | |
1396 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited | |
1397 | * to pending_buf_size, and each stored block has a 5 byte header: | |
1398 | */ | |
1399 | ulg max_block_size = 0xffff; | |
1400 | ulg max_start; | |
1401 | ||
1402 | if (max_block_size > s->pending_buf_size - 5) { | |
1403 | max_block_size = s->pending_buf_size - 5; | |
1404 | } | |
1405 | ||
1406 | /* Copy as much as possible from input to output: */ | |
1407 | for (;;) { | |
1408 | /* Fill the window as much as possible: */ | |
1409 | if (s->lookahead <= 1) { | |
1410 | ||
1411 | Assert(s->strstart < s->w_size+MAX_DIST(s) || | |
1e1cf689 | 1412 | s->block_start >= (long)s->w_size, "slide too late"); |
d4286ec4 PM |
1413 | |
1414 | fill_window(s); | |
1415 | if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; | |
1416 | ||
1417 | if (s->lookahead == 0) break; /* flush the current block */ | |
1418 | } | |
1e1cf689 | 1419 | Assert(s->block_start >= 0L, "block gone"); |
d4286ec4 | 1420 | |
1e1cf689 WD |
1421 | s->strstart += s->lookahead; |
1422 | s->lookahead = 0; | |
d4286ec4 | 1423 | |
0301b334 WD |
1424 | if (flush == Z_INSERT_ONLY) { |
1425 | s->block_start = s->strstart; | |
1426 | continue; | |
1427 | } | |
1428 | ||
1e1cf689 WD |
1429 | /* Emit a stored block if pending_buf will be full: */ |
1430 | max_start = s->block_start + max_block_size; | |
d4286ec4 | 1431 | if (s->strstart == 0 || (ulg)s->strstart >= max_start) { |
1e1cf689 WD |
1432 | /* strstart == 0 is possible when wraparound on 16-bit machine */ |
1433 | s->lookahead = (uInt)(s->strstart - max_start); | |
1434 | s->strstart = (uInt)max_start; | |
d4286ec4 | 1435 | FLUSH_BLOCK(s, 0); |
1e1cf689 WD |
1436 | } |
1437 | /* Flush if we may have to slide, otherwise block_start may become | |
d4286ec4 PM |
1438 | * negative and the data will be gone: |
1439 | */ | |
1440 | if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { | |
1441 | FLUSH_BLOCK(s, 0); | |
1e1cf689 | 1442 | } |
d4286ec4 | 1443 | } |
0301b334 WD |
1444 | if (flush == Z_INSERT_ONLY) { |
1445 | s->block_start = s->strstart; | |
1446 | return need_more; | |
1447 | } | |
1448 | ||
d4286ec4 PM |
1449 | FLUSH_BLOCK(s, flush == Z_FINISH); |
1450 | return flush == Z_FINISH ? finish_done : block_done; | |
1451 | } | |
1452 | ||
1453 | /* =========================================================================== | |
1454 | * Compress as much as possible from the input stream, return the current | |
1455 | * block state. | |
1456 | * This function does not perform lazy evaluation of matches and inserts | |
1457 | * new strings in the dictionary only for unmatched strings or for short | |
1458 | * matches. It is used only for the fast compression options. | |
1459 | */ | |
1460 | local block_state deflate_fast(s, flush) | |
1461 | deflate_state *s; | |
1462 | int flush; | |
1463 | { | |
1464 | IPos hash_head = NIL; /* head of the hash chain */ | |
1465 | int bflush; /* set if current block must be flushed */ | |
1466 | ||
1467 | for (;;) { | |
1468 | /* Make sure that we always have enough lookahead, except | |
1469 | * at the end of the input file. We need MAX_MATCH bytes | |
1470 | * for the next match, plus MIN_MATCH bytes to insert the | |
1471 | * string following the next match. | |
1472 | */ | |
1473 | if (s->lookahead < MIN_LOOKAHEAD) { | |
1474 | fill_window(s); | |
1475 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1e1cf689 WD |
1476 | return need_more; |
1477 | } | |
d4286ec4 PM |
1478 | if (s->lookahead == 0) break; /* flush the current block */ |
1479 | } | |
1480 | ||
1481 | /* Insert the string window[strstart .. strstart+2] in the | |
1482 | * dictionary, and set hash_head to the head of the hash chain: | |
1483 | */ | |
1484 | if (s->lookahead >= MIN_MATCH) { | |
1485 | INSERT_STRING(s, s->strstart, hash_head); | |
1486 | } | |
1487 | ||
5914bf15 PM |
1488 | if (flush == Z_INSERT_ONLY) { |
1489 | s->strstart++; | |
1490 | s->lookahead--; | |
1491 | continue; | |
1492 | } | |
1493 | ||
d4286ec4 PM |
1494 | /* Find the longest match, discarding those <= prev_length. |
1495 | * At this point we have always match_length < MIN_MATCH | |
1496 | */ | |
1497 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { | |
1498 | /* To simplify the code, we prevent matches with the string | |
1499 | * of window index 0 (in particular we have to avoid a match | |
1500 | * of the string with itself at the start of the input file). | |
1501 | */ | |
1e1cf689 | 1502 | #ifdef FASTEST |
cd426074 | 1503 | if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) || |
1e1cf689 WD |
1504 | (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { |
1505 | s->match_length = longest_match_fast (s, hash_head); | |
1506 | } | |
1507 | #else | |
cd426074 | 1508 | if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { |
d4286ec4 | 1509 | s->match_length = longest_match (s, hash_head); |
1e1cf689 WD |
1510 | } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { |
1511 | s->match_length = longest_match_fast (s, hash_head); | |
d4286ec4 | 1512 | } |
1e1cf689 WD |
1513 | #endif |
1514 | /* longest_match() or longest_match_fast() sets match_start */ | |
d4286ec4 PM |
1515 | } |
1516 | if (s->match_length >= MIN_MATCH) { | |
1517 | check_match(s, s->strstart, s->match_start, s->match_length); | |
1518 | ||
1519 | _tr_tally_dist(s, s->strstart - s->match_start, | |
1520 | s->match_length - MIN_MATCH, bflush); | |
1521 | ||
1522 | s->lookahead -= s->match_length; | |
1523 | ||
1524 | /* Insert new strings in the hash table only if the match length | |
1525 | * is not too large. This saves time but degrades compression. | |
1526 | */ | |
1527 | #ifndef FASTEST | |
1528 | if (s->match_length <= s->max_insert_length && | |
1529 | s->lookahead >= MIN_MATCH) { | |
1e1cf689 | 1530 | s->match_length--; /* string at strstart already in table */ |
d4286ec4 PM |
1531 | do { |
1532 | s->strstart++; | |
1533 | INSERT_STRING(s, s->strstart, hash_head); | |
1534 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are | |
1535 | * always MIN_MATCH bytes ahead. | |
1536 | */ | |
1537 | } while (--s->match_length != 0); | |
1e1cf689 | 1538 | s->strstart++; |
d4286ec4 PM |
1539 | } else |
1540 | #endif | |
1e1cf689 | 1541 | { |
d4286ec4 PM |
1542 | s->strstart += s->match_length; |
1543 | s->match_length = 0; | |
1544 | s->ins_h = s->window[s->strstart]; | |
1545 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
1546 | #if MIN_MATCH != 3 | |
1547 | Call UPDATE_HASH() MIN_MATCH-3 more times | |
1548 | #endif | |
1549 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not | |
1550 | * matter since it will be recomputed at next deflate call. | |
1551 | */ | |
1552 | } | |
1553 | } else { | |
1554 | /* No match, output a literal byte */ | |
1555 | Tracevv((stderr,"%c", s->window[s->strstart])); | |
1556 | _tr_tally_lit (s, s->window[s->strstart], bflush); | |
1557 | s->lookahead--; | |
1e1cf689 | 1558 | s->strstart++; |
d4286ec4 PM |
1559 | } |
1560 | if (bflush) FLUSH_BLOCK(s, 0); | |
1561 | } | |
5914bf15 PM |
1562 | if (flush == Z_INSERT_ONLY) { |
1563 | s->block_start = s->strstart; | |
1564 | return need_more; | |
1565 | } | |
d4286ec4 PM |
1566 | FLUSH_BLOCK(s, flush == Z_FINISH); |
1567 | return flush == Z_FINISH ? finish_done : block_done; | |
1568 | } | |
1569 | ||
1e1cf689 | 1570 | #ifndef FASTEST |
d4286ec4 PM |
1571 | /* =========================================================================== |
1572 | * Same as above, but achieves better compression. We use a lazy | |
1573 | * evaluation for matches: a match is finally adopted only if there is | |
1574 | * no better match at the next window position. | |
1575 | */ | |
1576 | local block_state deflate_slow(s, flush) | |
1577 | deflate_state *s; | |
1578 | int flush; | |
1579 | { | |
1580 | IPos hash_head = NIL; /* head of hash chain */ | |
1581 | int bflush; /* set if current block must be flushed */ | |
1582 | ||
1583 | /* Process the input block. */ | |
1584 | for (;;) { | |
1585 | /* Make sure that we always have enough lookahead, except | |
1586 | * at the end of the input file. We need MAX_MATCH bytes | |
1587 | * for the next match, plus MIN_MATCH bytes to insert the | |
1588 | * string following the next match. | |
1589 | */ | |
1590 | if (s->lookahead < MIN_LOOKAHEAD) { | |
1591 | fill_window(s); | |
1592 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1e1cf689 WD |
1593 | return need_more; |
1594 | } | |
d4286ec4 PM |
1595 | if (s->lookahead == 0) break; /* flush the current block */ |
1596 | } | |
1597 | ||
1598 | /* Insert the string window[strstart .. strstart+2] in the | |
1599 | * dictionary, and set hash_head to the head of the hash chain: | |
1600 | */ | |
1601 | if (s->lookahead >= MIN_MATCH) { | |
1602 | INSERT_STRING(s, s->strstart, hash_head); | |
1603 | } | |
1604 | ||
5914bf15 PM |
1605 | if (flush == Z_INSERT_ONLY) { |
1606 | s->strstart++; | |
1607 | s->lookahead--; | |
1608 | continue; | |
1609 | } | |
1610 | ||
d4286ec4 PM |
1611 | /* Find the longest match, discarding those <= prev_length. |
1612 | */ | |
1613 | s->prev_length = s->match_length, s->prev_match = s->match_start; | |
1614 | s->match_length = MIN_MATCH-1; | |
1615 | ||
1616 | if (hash_head != NIL && s->prev_length < s->max_lazy_match && | |
1617 | s->strstart - hash_head <= MAX_DIST(s)) { | |
1618 | /* To simplify the code, we prevent matches with the string | |
1619 | * of window index 0 (in particular we have to avoid a match | |
1620 | * of the string with itself at the start of the input file). | |
1621 | */ | |
cd426074 | 1622 | if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { |
d4286ec4 | 1623 | s->match_length = longest_match (s, hash_head); |
1e1cf689 WD |
1624 | } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { |
1625 | s->match_length = longest_match_fast (s, hash_head); | |
d4286ec4 | 1626 | } |
1e1cf689 | 1627 | /* longest_match() or longest_match_fast() sets match_start */ |
d4286ec4 | 1628 | |
1e1cf689 WD |
1629 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED |
1630 | #if TOO_FAR <= 32767 | |
1631 | || (s->match_length == MIN_MATCH && | |
1632 | s->strstart - s->match_start > TOO_FAR) | |
1633 | #endif | |
1634 | )) { | |
d4286ec4 PM |
1635 | |
1636 | /* If prev_match is also MIN_MATCH, match_start is garbage | |
1637 | * but we will ignore the current match anyway. | |
1638 | */ | |
1639 | s->match_length = MIN_MATCH-1; | |
1640 | } | |
1641 | } | |
1642 | /* If there was a match at the previous step and the current | |
1643 | * match is not better, output the previous match: | |
1644 | */ | |
1645 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { | |
1646 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; | |
1647 | /* Do not insert strings in hash table beyond this. */ | |
1648 | ||
1649 | check_match(s, s->strstart-1, s->prev_match, s->prev_length); | |
1650 | ||
1651 | _tr_tally_dist(s, s->strstart -1 - s->prev_match, | |
1e1cf689 | 1652 | s->prev_length - MIN_MATCH, bflush); |
d4286ec4 PM |
1653 | |
1654 | /* Insert in hash table all strings up to the end of the match. | |
1655 | * strstart-1 and strstart are already inserted. If there is not | |
1656 | * enough lookahead, the last two strings are not inserted in | |
1657 | * the hash table. | |
1658 | */ | |
1659 | s->lookahead -= s->prev_length-1; | |
1660 | s->prev_length -= 2; | |
1661 | do { | |
1662 | if (++s->strstart <= max_insert) { | |
1663 | INSERT_STRING(s, s->strstart, hash_head); | |
1664 | } | |
1665 | } while (--s->prev_length != 0); | |
1666 | s->match_available = 0; | |
1667 | s->match_length = MIN_MATCH-1; | |
1668 | s->strstart++; | |
1669 | ||
1670 | if (bflush) FLUSH_BLOCK(s, 0); | |
1671 | ||
1672 | } else if (s->match_available) { | |
1673 | /* If there was no match at the previous position, output a | |
1674 | * single literal. If there was a match but the current match | |
1675 | * is longer, truncate the previous match to a single literal. | |
1676 | */ | |
1677 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
1e1cf689 WD |
1678 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); |
1679 | if (bflush) { | |
d4286ec4 PM |
1680 | FLUSH_BLOCK_ONLY(s, 0); |
1681 | } | |
1682 | s->strstart++; | |
1683 | s->lookahead--; | |
1684 | if (s->strm->avail_out == 0) return need_more; | |
1685 | } else { | |
1686 | /* There is no previous match to compare with, wait for | |
1687 | * the next step to decide. | |
1688 | */ | |
1689 | s->match_available = 1; | |
1690 | s->strstart++; | |
1691 | s->lookahead--; | |
1692 | } | |
1693 | } | |
5914bf15 PM |
1694 | if (flush == Z_INSERT_ONLY) { |
1695 | s->block_start = s->strstart; | |
1696 | return need_more; | |
1697 | } | |
d4286ec4 PM |
1698 | Assert (flush != Z_NO_FLUSH, "no flush?"); |
1699 | if (s->match_available) { | |
1700 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
1701 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
1702 | s->match_available = 0; | |
1703 | } | |
1704 | FLUSH_BLOCK(s, flush == Z_FINISH); | |
1705 | return flush == Z_FINISH ? finish_done : block_done; | |
1706 | } | |
1e1cf689 | 1707 | #endif /* FASTEST */ |
cd426074 WD |
1708 | |
1709 | #if 0 | |
1710 | /* =========================================================================== | |
1711 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance | |
1712 | * one. Do not maintain a hash table. (It will be regenerated if this run of | |
1713 | * deflate switches away from Z_RLE.) | |
1714 | */ | |
1715 | local block_state deflate_rle(s, flush) | |
1716 | deflate_state *s; | |
1717 | int flush; | |
1718 | { | |
1719 | int bflush; /* set if current block must be flushed */ | |
1720 | uInt run; /* length of run */ | |
1721 | uInt max; /* maximum length of run */ | |
1722 | uInt prev; /* byte at distance one to match */ | |
1723 | Bytef *scan; /* scan for end of run */ | |
1724 | ||
1725 | for (;;) { | |
1726 | /* Make sure that we always have enough lookahead, except | |
1727 | * at the end of the input file. We need MAX_MATCH bytes | |
1728 | * for the longest encodable run. | |
1729 | */ | |
1730 | if (s->lookahead < MAX_MATCH) { | |
1731 | fill_window(s); | |
1732 | if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { | |
1733 | return need_more; | |
1734 | } | |
1735 | if (s->lookahead == 0) break; /* flush the current block */ | |
1736 | } | |
1737 | ||
1738 | /* See how many times the previous byte repeats */ | |
1739 | run = 0; | |
1740 | if (s->strstart > 0) { /* if there is a previous byte, that is */ | |
1741 | max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH; | |
1742 | scan = s->window + s->strstart - 1; | |
1743 | prev = *scan++; | |
1744 | do { | |
1745 | if (*scan++ != prev) | |
1746 | break; | |
1747 | } while (++run < max); | |
1748 | } | |
1749 | ||
1750 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */ | |
1751 | if (run >= MIN_MATCH) { | |
1752 | check_match(s, s->strstart, s->strstart - 1, run); | |
1753 | _tr_tally_dist(s, 1, run - MIN_MATCH, bflush); | |
1754 | s->lookahead -= run; | |
1755 | s->strstart += run; | |
1756 | } else { | |
1757 | /* No match, output a literal byte */ | |
1758 | Tracevv((stderr,"%c", s->window[s->strstart])); | |
1759 | _tr_tally_lit (s, s->window[s->strstart], bflush); | |
1760 | s->lookahead--; | |
1761 | s->strstart++; | |
1762 | } | |
1763 | if (bflush) FLUSH_BLOCK(s, 0); | |
1764 | } | |
1765 | FLUSH_BLOCK(s, flush == Z_FINISH); | |
1766 | return flush == Z_FINISH ? finish_done : block_done; | |
1767 | } | |
1768 | #endif |