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5ca28f79 | 1 | /* deflate.c -- compress data using the deflation algorithm |
de1ab01e | 2 | * Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler |
5ca28f79 L |
3 | * For conditions of distribution and use, see copyright notice in zlib.h |
4 | */ | |
5 | ||
6 | /* | |
7 | * ALGORITHM | |
8 | * | |
9 | * The "deflation" process depends on being able to identify portions | |
10 | * of the input text which are identical to earlier input (within a | |
11 | * sliding window trailing behind the input currently being processed). | |
12 | * | |
13 | * The most straightforward technique turns out to be the fastest for | |
14 | * most input files: try all possible matches and select the longest. | |
15 | * The key feature of this algorithm is that insertions into the string | |
16 | * dictionary are very simple and thus fast, and deletions are avoided | |
17 | * completely. Insertions are performed at each input character, whereas | |
18 | * string matches are performed only when the previous match ends. So it | |
19 | * is preferable to spend more time in matches to allow very fast string | |
20 | * insertions and avoid deletions. The matching algorithm for small | |
21 | * strings is inspired from that of Rabin & Karp. A brute force approach | |
22 | * is used to find longer strings when a small match has been found. | |
23 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze | |
24 | * (by Leonid Broukhis). | |
25 | * A previous version of this file used a more sophisticated algorithm | |
26 | * (by Fiala and Greene) which is guaranteed to run in linear amortized | |
27 | * time, but has a larger average cost, uses more memory and is patented. | |
28 | * However the F&G algorithm may be faster for some highly redundant | |
29 | * files if the parameter max_chain_length (described below) is too large. | |
30 | * | |
31 | * ACKNOWLEDGEMENTS | |
32 | * | |
33 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and | |
34 | * I found it in 'freeze' written by Leonid Broukhis. | |
35 | * Thanks to many people for bug reports and testing. | |
36 | * | |
37 | * REFERENCES | |
38 | * | |
39 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". | |
40 | * Available in http://tools.ietf.org/html/rfc1951 | |
41 | * | |
42 | * A description of the Rabin and Karp algorithm is given in the book | |
43 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. | |
44 | * | |
45 | * Fiala,E.R., and Greene,D.H. | |
46 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 | |
47 | * | |
48 | */ | |
49 | ||
50 | /* @(#) $Id: deflate.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */ | |
51 | ||
52 | #include "deflate.h" | |
53 | ||
54 | const char deflate_copyright[] = | |
9c7e3b0e | 55 | " deflate 1.2.11 Copyright 1995-2017 Jean-loup Gailly and Mark Adler "; |
5ca28f79 L |
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 | ||
de1ab01e NC |
76 | local int deflateStateCheck OF((z_streamp strm)); |
77 | local void slide_hash OF((deflate_state *s)); | |
5ca28f79 L |
78 | local void fill_window OF((deflate_state *s)); |
79 | local block_state deflate_stored OF((deflate_state *s, int flush)); | |
80 | local block_state deflate_fast OF((deflate_state *s, int flush)); | |
81 | #ifndef FASTEST | |
82 | local block_state deflate_slow OF((deflate_state *s, int flush)); | |
83 | #endif | |
84 | local block_state deflate_rle OF((deflate_state *s, int flush)); | |
85 | local block_state deflate_huff OF((deflate_state *s, int flush)); | |
86 | local void lm_init OF((deflate_state *s)); | |
87 | local void putShortMSB OF((deflate_state *s, uInt b)); | |
88 | local void flush_pending OF((z_streamp strm)); | |
de1ab01e | 89 | local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); |
5ca28f79 | 90 | #ifdef ASMV |
de1ab01e | 91 | # pragma message("Assembler code may have bugs -- use at your own risk") |
5ca28f79 L |
92 | void match_init OF((void)); /* asm code initialization */ |
93 | uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
94 | #else | |
95 | local uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
96 | #endif | |
97 | ||
de1ab01e | 98 | #ifdef ZLIB_DEBUG |
5ca28f79 L |
99 | local void check_match OF((deflate_state *s, IPos start, IPos match, |
100 | int length)); | |
101 | #endif | |
102 | ||
103 | /* =========================================================================== | |
104 | * Local data | |
105 | */ | |
106 | ||
107 | #define NIL 0 | |
108 | /* Tail of hash chains */ | |
109 | ||
110 | #ifndef TOO_FAR | |
111 | # define TOO_FAR 4096 | |
112 | #endif | |
113 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ | |
114 | ||
115 | /* Values for max_lazy_match, good_match and max_chain_length, depending on | |
116 | * the desired pack level (0..9). The values given below have been tuned to | |
117 | * exclude worst case performance for pathological files. Better values may be | |
118 | * found for specific files. | |
119 | */ | |
120 | typedef struct config_s { | |
121 | ush good_length; /* reduce lazy search above this match length */ | |
122 | ush max_lazy; /* do not perform lazy search above this match length */ | |
123 | ush nice_length; /* quit search above this match length */ | |
124 | ush max_chain; | |
125 | compress_func func; | |
126 | } config; | |
127 | ||
128 | #ifdef FASTEST | |
129 | local const config configuration_table[2] = { | |
130 | /* good lazy nice chain */ | |
131 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
132 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ | |
133 | #else | |
134 | local const config configuration_table[10] = { | |
135 | /* good lazy nice chain */ | |
136 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
137 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ | |
138 | /* 2 */ {4, 5, 16, 8, deflate_fast}, | |
139 | /* 3 */ {4, 6, 32, 32, deflate_fast}, | |
140 | ||
141 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ | |
142 | /* 5 */ {8, 16, 32, 32, deflate_slow}, | |
143 | /* 6 */ {8, 16, 128, 128, deflate_slow}, | |
144 | /* 7 */ {8, 32, 128, 256, deflate_slow}, | |
145 | /* 8 */ {32, 128, 258, 1024, deflate_slow}, | |
146 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ | |
147 | #endif | |
148 | ||
149 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 | |
150 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different | |
151 | * meaning. | |
152 | */ | |
153 | ||
5ca28f79 | 154 | /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */ |
de1ab01e | 155 | #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0)) |
5ca28f79 L |
156 | |
157 | /* =========================================================================== | |
158 | * Update a hash value with the given input byte | |
de1ab01e NC |
159 | * IN assertion: all calls to UPDATE_HASH are made with consecutive input |
160 | * characters, so that a running hash key can be computed from the previous | |
161 | * key instead of complete recalculation each time. | |
5ca28f79 L |
162 | */ |
163 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) | |
164 | ||
165 | ||
166 | /* =========================================================================== | |
167 | * Insert string str in the dictionary and set match_head to the previous head | |
168 | * of the hash chain (the most recent string with same hash key). Return | |
169 | * the previous length of the hash chain. | |
170 | * If this file is compiled with -DFASTEST, the compression level is forced | |
171 | * to 1, and no hash chains are maintained. | |
de1ab01e NC |
172 | * IN assertion: all calls to INSERT_STRING are made with consecutive input |
173 | * characters and the first MIN_MATCH bytes of str are valid (except for | |
174 | * the last MIN_MATCH-1 bytes of the input file). | |
5ca28f79 L |
175 | */ |
176 | #ifdef FASTEST | |
177 | #define INSERT_STRING(s, str, match_head) \ | |
178 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
179 | match_head = s->head[s->ins_h], \ | |
180 | s->head[s->ins_h] = (Pos)(str)) | |
181 | #else | |
182 | #define INSERT_STRING(s, str, match_head) \ | |
183 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
184 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ | |
185 | s->head[s->ins_h] = (Pos)(str)) | |
186 | #endif | |
187 | ||
188 | /* =========================================================================== | |
189 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems). | |
190 | * prev[] will be initialized on the fly. | |
191 | */ | |
192 | #define CLEAR_HASH(s) \ | |
193 | s->head[s->hash_size-1] = NIL; \ | |
194 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); | |
195 | ||
de1ab01e NC |
196 | /* =========================================================================== |
197 | * Slide the hash table when sliding the window down (could be avoided with 32 | |
198 | * bit values at the expense of memory usage). We slide even when level == 0 to | |
199 | * keep the hash table consistent if we switch back to level > 0 later. | |
200 | */ | |
201 | local void slide_hash(s) | |
202 | deflate_state *s; | |
203 | { | |
204 | unsigned n, m; | |
205 | Posf *p; | |
206 | uInt wsize = s->w_size; | |
207 | ||
208 | n = s->hash_size; | |
209 | p = &s->head[n]; | |
210 | do { | |
211 | m = *--p; | |
212 | *p = (Pos)(m >= wsize ? m - wsize : NIL); | |
213 | } while (--n); | |
214 | n = wsize; | |
215 | #ifndef FASTEST | |
216 | p = &s->prev[n]; | |
217 | do { | |
218 | m = *--p; | |
219 | *p = (Pos)(m >= wsize ? m - wsize : NIL); | |
220 | /* If n is not on any hash chain, prev[n] is garbage but | |
221 | * its value will never be used. | |
222 | */ | |
223 | } while (--n); | |
224 | #endif | |
225 | } | |
226 | ||
5ca28f79 L |
227 | /* ========================================================================= */ |
228 | int ZEXPORT deflateInit_(strm, level, version, stream_size) | |
229 | z_streamp strm; | |
230 | int level; | |
231 | const char *version; | |
232 | int stream_size; | |
233 | { | |
234 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, | |
235 | Z_DEFAULT_STRATEGY, version, stream_size); | |
236 | /* To do: ignore strm->next_in if we use it as window */ | |
237 | } | |
238 | ||
239 | /* ========================================================================= */ | |
240 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, | |
241 | version, stream_size) | |
242 | z_streamp strm; | |
243 | int level; | |
244 | int method; | |
245 | int windowBits; | |
246 | int memLevel; | |
247 | int strategy; | |
248 | const char *version; | |
249 | int stream_size; | |
250 | { | |
251 | deflate_state *s; | |
252 | int wrap = 1; | |
253 | static const char my_version[] = ZLIB_VERSION; | |
254 | ||
255 | ushf *overlay; | |
256 | /* We overlay pending_buf and d_buf+l_buf. This works since the average | |
257 | * output size for (length,distance) codes is <= 24 bits. | |
258 | */ | |
259 | ||
260 | if (version == Z_NULL || version[0] != my_version[0] || | |
261 | stream_size != sizeof(z_stream)) { | |
262 | return Z_VERSION_ERROR; | |
263 | } | |
264 | if (strm == Z_NULL) return Z_STREAM_ERROR; | |
265 | ||
266 | strm->msg = Z_NULL; | |
267 | if (strm->zalloc == (alloc_func)0) { | |
268 | #ifdef Z_SOLO | |
269 | return Z_STREAM_ERROR; | |
270 | #else | |
271 | strm->zalloc = zcalloc; | |
272 | strm->opaque = (voidpf)0; | |
273 | #endif | |
274 | } | |
275 | if (strm->zfree == (free_func)0) | |
276 | #ifdef Z_SOLO | |
277 | return Z_STREAM_ERROR; | |
278 | #else | |
279 | strm->zfree = zcfree; | |
280 | #endif | |
281 | ||
282 | #ifdef FASTEST | |
283 | if (level != 0) level = 1; | |
284 | #else | |
285 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
286 | #endif | |
287 | ||
288 | if (windowBits < 0) { /* suppress zlib wrapper */ | |
289 | wrap = 0; | |
290 | windowBits = -windowBits; | |
291 | } | |
292 | #ifdef GZIP | |
293 | else if (windowBits > 15) { | |
294 | wrap = 2; /* write gzip wrapper instead */ | |
295 | windowBits -= 16; | |
296 | } | |
297 | #endif | |
298 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || | |
299 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || | |
de1ab01e | 300 | strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) { |
5ca28f79 L |
301 | return Z_STREAM_ERROR; |
302 | } | |
303 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ | |
304 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); | |
305 | if (s == Z_NULL) return Z_MEM_ERROR; | |
306 | strm->state = (struct internal_state FAR *)s; | |
307 | s->strm = strm; | |
de1ab01e | 308 | s->status = INIT_STATE; /* to pass state test in deflateReset() */ |
5ca28f79 L |
309 | |
310 | s->wrap = wrap; | |
311 | s->gzhead = Z_NULL; | |
de1ab01e | 312 | s->w_bits = (uInt)windowBits; |
5ca28f79 L |
313 | s->w_size = 1 << s->w_bits; |
314 | s->w_mask = s->w_size - 1; | |
315 | ||
de1ab01e | 316 | s->hash_bits = (uInt)memLevel + 7; |
5ca28f79 L |
317 | s->hash_size = 1 << s->hash_bits; |
318 | s->hash_mask = s->hash_size - 1; | |
319 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); | |
320 | ||
321 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); | |
322 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); | |
323 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); | |
324 | ||
325 | s->high_water = 0; /* nothing written to s->window yet */ | |
326 | ||
327 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ | |
328 | ||
329 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); | |
330 | s->pending_buf = (uchf *) overlay; | |
331 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); | |
332 | ||
333 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || | |
334 | s->pending_buf == Z_NULL) { | |
335 | s->status = FINISH_STATE; | |
da09a436 | 336 | strm->msg = ERR_MSG(Z_MEM_ERROR); |
5ca28f79 L |
337 | deflateEnd (strm); |
338 | return Z_MEM_ERROR; | |
339 | } | |
340 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush); | |
341 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; | |
342 | ||
343 | s->level = level; | |
344 | s->strategy = strategy; | |
345 | s->method = (Byte)method; | |
346 | ||
347 | return deflateReset(strm); | |
348 | } | |
349 | ||
de1ab01e NC |
350 | /* ========================================================================= |
351 | * Check for a valid deflate stream state. Return 0 if ok, 1 if not. | |
352 | */ | |
353 | local int deflateStateCheck (strm) | |
354 | z_streamp strm; | |
355 | { | |
356 | deflate_state *s; | |
357 | if (strm == Z_NULL || | |
358 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) | |
359 | return 1; | |
360 | s = strm->state; | |
361 | if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE && | |
362 | #ifdef GZIP | |
363 | s->status != GZIP_STATE && | |
364 | #endif | |
365 | s->status != EXTRA_STATE && | |
366 | s->status != NAME_STATE && | |
367 | s->status != COMMENT_STATE && | |
368 | s->status != HCRC_STATE && | |
369 | s->status != BUSY_STATE && | |
370 | s->status != FINISH_STATE)) | |
371 | return 1; | |
372 | return 0; | |
373 | } | |
374 | ||
5ca28f79 L |
375 | /* ========================================================================= */ |
376 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) | |
377 | z_streamp strm; | |
378 | const Bytef *dictionary; | |
379 | uInt dictLength; | |
380 | { | |
381 | deflate_state *s; | |
382 | uInt str, n; | |
383 | int wrap; | |
384 | unsigned avail; | |
da09a436 | 385 | z_const unsigned char *next; |
5ca28f79 | 386 | |
de1ab01e | 387 | if (deflateStateCheck(strm) || dictionary == Z_NULL) |
5ca28f79 L |
388 | return Z_STREAM_ERROR; |
389 | s = strm->state; | |
390 | wrap = s->wrap; | |
391 | if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) | |
392 | return Z_STREAM_ERROR; | |
393 | ||
394 | /* when using zlib wrappers, compute Adler-32 for provided dictionary */ | |
395 | if (wrap == 1) | |
396 | strm->adler = adler32(strm->adler, dictionary, dictLength); | |
397 | s->wrap = 0; /* avoid computing Adler-32 in read_buf */ | |
398 | ||
399 | /* if dictionary would fill window, just replace the history */ | |
400 | if (dictLength >= s->w_size) { | |
401 | if (wrap == 0) { /* already empty otherwise */ | |
402 | CLEAR_HASH(s); | |
403 | s->strstart = 0; | |
404 | s->block_start = 0L; | |
405 | s->insert = 0; | |
406 | } | |
407 | dictionary += dictLength - s->w_size; /* use the tail */ | |
408 | dictLength = s->w_size; | |
409 | } | |
410 | ||
411 | /* insert dictionary into window and hash */ | |
412 | avail = strm->avail_in; | |
413 | next = strm->next_in; | |
414 | strm->avail_in = dictLength; | |
da09a436 | 415 | strm->next_in = (z_const Bytef *)dictionary; |
5ca28f79 L |
416 | fill_window(s); |
417 | while (s->lookahead >= MIN_MATCH) { | |
418 | str = s->strstart; | |
419 | n = s->lookahead - (MIN_MATCH-1); | |
420 | do { | |
421 | UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); | |
422 | #ifndef FASTEST | |
423 | s->prev[str & s->w_mask] = s->head[s->ins_h]; | |
424 | #endif | |
425 | s->head[s->ins_h] = (Pos)str; | |
426 | str++; | |
427 | } while (--n); | |
428 | s->strstart = str; | |
429 | s->lookahead = MIN_MATCH-1; | |
430 | fill_window(s); | |
431 | } | |
432 | s->strstart += s->lookahead; | |
433 | s->block_start = (long)s->strstart; | |
434 | s->insert = s->lookahead; | |
435 | s->lookahead = 0; | |
436 | s->match_length = s->prev_length = MIN_MATCH-1; | |
437 | s->match_available = 0; | |
438 | strm->next_in = next; | |
439 | strm->avail_in = avail; | |
440 | s->wrap = wrap; | |
441 | return Z_OK; | |
442 | } | |
443 | ||
de1ab01e NC |
444 | /* ========================================================================= */ |
445 | int ZEXPORT deflateGetDictionary (strm, dictionary, dictLength) | |
446 | z_streamp strm; | |
447 | Bytef *dictionary; | |
448 | uInt *dictLength; | |
449 | { | |
450 | deflate_state *s; | |
451 | uInt len; | |
452 | ||
453 | if (deflateStateCheck(strm)) | |
454 | return Z_STREAM_ERROR; | |
455 | s = strm->state; | |
456 | len = s->strstart + s->lookahead; | |
457 | if (len > s->w_size) | |
458 | len = s->w_size; | |
459 | if (dictionary != Z_NULL && len) | |
460 | zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len); | |
461 | if (dictLength != Z_NULL) | |
462 | *dictLength = len; | |
463 | return Z_OK; | |
464 | } | |
465 | ||
5ca28f79 L |
466 | /* ========================================================================= */ |
467 | int ZEXPORT deflateResetKeep (strm) | |
468 | z_streamp strm; | |
469 | { | |
470 | deflate_state *s; | |
471 | ||
de1ab01e | 472 | if (deflateStateCheck(strm)) { |
5ca28f79 L |
473 | return Z_STREAM_ERROR; |
474 | } | |
475 | ||
476 | strm->total_in = strm->total_out = 0; | |
477 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ | |
478 | strm->data_type = Z_UNKNOWN; | |
479 | ||
480 | s = (deflate_state *)strm->state; | |
481 | s->pending = 0; | |
482 | s->pending_out = s->pending_buf; | |
483 | ||
484 | if (s->wrap < 0) { | |
485 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ | |
486 | } | |
de1ab01e NC |
487 | s->status = |
488 | #ifdef GZIP | |
489 | s->wrap == 2 ? GZIP_STATE : | |
490 | #endif | |
491 | s->wrap ? INIT_STATE : BUSY_STATE; | |
5ca28f79 L |
492 | strm->adler = |
493 | #ifdef GZIP | |
494 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) : | |
495 | #endif | |
496 | adler32(0L, Z_NULL, 0); | |
497 | s->last_flush = Z_NO_FLUSH; | |
498 | ||
499 | _tr_init(s); | |
500 | ||
501 | return Z_OK; | |
502 | } | |
503 | ||
504 | /* ========================================================================= */ | |
505 | int ZEXPORT deflateReset (strm) | |
506 | z_streamp strm; | |
507 | { | |
508 | int ret; | |
509 | ||
510 | ret = deflateResetKeep(strm); | |
511 | if (ret == Z_OK) | |
512 | lm_init(strm->state); | |
513 | return ret; | |
514 | } | |
515 | ||
516 | /* ========================================================================= */ | |
517 | int ZEXPORT deflateSetHeader (strm, head) | |
518 | z_streamp strm; | |
519 | gz_headerp head; | |
520 | { | |
de1ab01e NC |
521 | if (deflateStateCheck(strm) || strm->state->wrap != 2) |
522 | return Z_STREAM_ERROR; | |
5ca28f79 L |
523 | strm->state->gzhead = head; |
524 | return Z_OK; | |
525 | } | |
526 | ||
527 | /* ========================================================================= */ | |
528 | int ZEXPORT deflatePending (strm, pending, bits) | |
529 | unsigned *pending; | |
530 | int *bits; | |
531 | z_streamp strm; | |
532 | { | |
de1ab01e | 533 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
534 | if (pending != Z_NULL) |
535 | *pending = strm->state->pending; | |
536 | if (bits != Z_NULL) | |
537 | *bits = strm->state->bi_valid; | |
538 | return Z_OK; | |
539 | } | |
540 | ||
541 | /* ========================================================================= */ | |
542 | int ZEXPORT deflatePrime (strm, bits, value) | |
543 | z_streamp strm; | |
544 | int bits; | |
545 | int value; | |
546 | { | |
547 | deflate_state *s; | |
548 | int put; | |
549 | ||
de1ab01e | 550 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
551 | s = strm->state; |
552 | if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3)) | |
553 | return Z_BUF_ERROR; | |
554 | do { | |
555 | put = Buf_size - s->bi_valid; | |
556 | if (put > bits) | |
557 | put = bits; | |
558 | s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); | |
559 | s->bi_valid += put; | |
560 | _tr_flush_bits(s); | |
561 | value >>= put; | |
562 | bits -= put; | |
563 | } while (bits); | |
564 | return Z_OK; | |
565 | } | |
566 | ||
567 | /* ========================================================================= */ | |
568 | int ZEXPORT deflateParams(strm, level, strategy) | |
569 | z_streamp strm; | |
570 | int level; | |
571 | int strategy; | |
572 | { | |
573 | deflate_state *s; | |
574 | compress_func func; | |
5ca28f79 | 575 | |
de1ab01e | 576 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
577 | s = strm->state; |
578 | ||
579 | #ifdef FASTEST | |
580 | if (level != 0) level = 1; | |
581 | #else | |
582 | if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
583 | #endif | |
584 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { | |
585 | return Z_STREAM_ERROR; | |
586 | } | |
587 | func = configuration_table[s->level].func; | |
588 | ||
9c7e3b0e NC |
589 | if ((strategy != s->strategy || func != configuration_table[level].func) && |
590 | s->high_water) { | |
5ca28f79 | 591 | /* Flush the last buffer: */ |
de1ab01e NC |
592 | int err = deflate(strm, Z_BLOCK); |
593 | if (err == Z_STREAM_ERROR) | |
594 | return err; | |
595 | if (strm->avail_out == 0) | |
596 | return Z_BUF_ERROR; | |
5ca28f79 L |
597 | } |
598 | if (s->level != level) { | |
de1ab01e NC |
599 | if (s->level == 0 && s->matches != 0) { |
600 | if (s->matches == 1) | |
601 | slide_hash(s); | |
602 | else | |
603 | CLEAR_HASH(s); | |
604 | s->matches = 0; | |
605 | } | |
5ca28f79 L |
606 | s->level = level; |
607 | s->max_lazy_match = configuration_table[level].max_lazy; | |
608 | s->good_match = configuration_table[level].good_length; | |
609 | s->nice_match = configuration_table[level].nice_length; | |
610 | s->max_chain_length = configuration_table[level].max_chain; | |
611 | } | |
612 | s->strategy = strategy; | |
de1ab01e | 613 | return Z_OK; |
5ca28f79 L |
614 | } |
615 | ||
616 | /* ========================================================================= */ | |
617 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) | |
618 | z_streamp strm; | |
619 | int good_length; | |
620 | int max_lazy; | |
621 | int nice_length; | |
622 | int max_chain; | |
623 | { | |
624 | deflate_state *s; | |
625 | ||
de1ab01e | 626 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 | 627 | s = strm->state; |
de1ab01e NC |
628 | s->good_match = (uInt)good_length; |
629 | s->max_lazy_match = (uInt)max_lazy; | |
5ca28f79 | 630 | s->nice_match = nice_length; |
de1ab01e | 631 | s->max_chain_length = (uInt)max_chain; |
5ca28f79 L |
632 | return Z_OK; |
633 | } | |
634 | ||
635 | /* ========================================================================= | |
636 | * For the default windowBits of 15 and memLevel of 8, this function returns | |
637 | * a close to exact, as well as small, upper bound on the compressed size. | |
638 | * They are coded as constants here for a reason--if the #define's are | |
639 | * changed, then this function needs to be changed as well. The return | |
640 | * value for 15 and 8 only works for those exact settings. | |
641 | * | |
642 | * For any setting other than those defaults for windowBits and memLevel, | |
643 | * the value returned is a conservative worst case for the maximum expansion | |
644 | * resulting from using fixed blocks instead of stored blocks, which deflate | |
645 | * can emit on compressed data for some combinations of the parameters. | |
646 | * | |
647 | * This function could be more sophisticated to provide closer upper bounds for | |
648 | * every combination of windowBits and memLevel. But even the conservative | |
649 | * upper bound of about 14% expansion does not seem onerous for output buffer | |
650 | * allocation. | |
651 | */ | |
652 | uLong ZEXPORT deflateBound(strm, sourceLen) | |
653 | z_streamp strm; | |
654 | uLong sourceLen; | |
655 | { | |
656 | deflate_state *s; | |
657 | uLong complen, wraplen; | |
5ca28f79 L |
658 | |
659 | /* conservative upper bound for compressed data */ | |
660 | complen = sourceLen + | |
661 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; | |
662 | ||
663 | /* if can't get parameters, return conservative bound plus zlib wrapper */ | |
de1ab01e | 664 | if (deflateStateCheck(strm)) |
5ca28f79 L |
665 | return complen + 6; |
666 | ||
667 | /* compute wrapper length */ | |
668 | s = strm->state; | |
669 | switch (s->wrap) { | |
670 | case 0: /* raw deflate */ | |
671 | wraplen = 0; | |
672 | break; | |
673 | case 1: /* zlib wrapper */ | |
674 | wraplen = 6 + (s->strstart ? 4 : 0); | |
675 | break; | |
de1ab01e | 676 | #ifdef GZIP |
5ca28f79 L |
677 | case 2: /* gzip wrapper */ |
678 | wraplen = 18; | |
679 | if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ | |
de1ab01e | 680 | Bytef *str; |
5ca28f79 L |
681 | if (s->gzhead->extra != Z_NULL) |
682 | wraplen += 2 + s->gzhead->extra_len; | |
683 | str = s->gzhead->name; | |
684 | if (str != Z_NULL) | |
685 | do { | |
686 | wraplen++; | |
687 | } while (*str++); | |
688 | str = s->gzhead->comment; | |
689 | if (str != Z_NULL) | |
690 | do { | |
691 | wraplen++; | |
692 | } while (*str++); | |
693 | if (s->gzhead->hcrc) | |
694 | wraplen += 2; | |
695 | } | |
696 | break; | |
de1ab01e | 697 | #endif |
5ca28f79 L |
698 | default: /* for compiler happiness */ |
699 | wraplen = 6; | |
700 | } | |
701 | ||
702 | /* if not default parameters, return conservative bound */ | |
703 | if (s->w_bits != 15 || s->hash_bits != 8 + 7) | |
704 | return complen + wraplen; | |
705 | ||
706 | /* default settings: return tight bound for that case */ | |
707 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + | |
708 | (sourceLen >> 25) + 13 - 6 + wraplen; | |
709 | } | |
710 | ||
711 | /* ========================================================================= | |
712 | * Put a short in the pending buffer. The 16-bit value is put in MSB order. | |
713 | * IN assertion: the stream state is correct and there is enough room in | |
714 | * pending_buf. | |
715 | */ | |
716 | local void putShortMSB (s, b) | |
717 | deflate_state *s; | |
718 | uInt b; | |
719 | { | |
720 | put_byte(s, (Byte)(b >> 8)); | |
721 | put_byte(s, (Byte)(b & 0xff)); | |
722 | } | |
723 | ||
724 | /* ========================================================================= | |
de1ab01e NC |
725 | * Flush as much pending output as possible. All deflate() output, except for |
726 | * some deflate_stored() output, goes through this function so some | |
727 | * applications may wish to modify it to avoid allocating a large | |
728 | * strm->next_out buffer and copying into it. (See also read_buf()). | |
5ca28f79 L |
729 | */ |
730 | local void flush_pending(strm) | |
731 | z_streamp strm; | |
732 | { | |
733 | unsigned len; | |
734 | deflate_state *s = strm->state; | |
735 | ||
736 | _tr_flush_bits(s); | |
737 | len = s->pending; | |
738 | if (len > strm->avail_out) len = strm->avail_out; | |
739 | if (len == 0) return; | |
740 | ||
741 | zmemcpy(strm->next_out, s->pending_out, len); | |
742 | strm->next_out += len; | |
743 | s->pending_out += len; | |
744 | strm->total_out += len; | |
de1ab01e NC |
745 | strm->avail_out -= len; |
746 | s->pending -= len; | |
5ca28f79 L |
747 | if (s->pending == 0) { |
748 | s->pending_out = s->pending_buf; | |
749 | } | |
750 | } | |
751 | ||
de1ab01e NC |
752 | /* =========================================================================== |
753 | * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1]. | |
754 | */ | |
755 | #define HCRC_UPDATE(beg) \ | |
756 | do { \ | |
757 | if (s->gzhead->hcrc && s->pending > (beg)) \ | |
758 | strm->adler = crc32(strm->adler, s->pending_buf + (beg), \ | |
759 | s->pending - (beg)); \ | |
760 | } while (0) | |
761 | ||
5ca28f79 L |
762 | /* ========================================================================= */ |
763 | int ZEXPORT deflate (strm, flush) | |
764 | z_streamp strm; | |
765 | int flush; | |
766 | { | |
767 | int old_flush; /* value of flush param for previous deflate call */ | |
768 | deflate_state *s; | |
769 | ||
de1ab01e | 770 | if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { |
5ca28f79 L |
771 | return Z_STREAM_ERROR; |
772 | } | |
773 | s = strm->state; | |
774 | ||
775 | if (strm->next_out == Z_NULL || | |
de1ab01e | 776 | (strm->avail_in != 0 && strm->next_in == Z_NULL) || |
5ca28f79 L |
777 | (s->status == FINISH_STATE && flush != Z_FINISH)) { |
778 | ERR_RETURN(strm, Z_STREAM_ERROR); | |
779 | } | |
780 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); | |
781 | ||
5ca28f79 L |
782 | old_flush = s->last_flush; |
783 | s->last_flush = flush; | |
784 | ||
de1ab01e NC |
785 | /* Flush as much pending output as possible */ |
786 | if (s->pending != 0) { | |
787 | flush_pending(strm); | |
788 | if (strm->avail_out == 0) { | |
789 | /* Since avail_out is 0, deflate will be called again with | |
790 | * more output space, but possibly with both pending and | |
791 | * avail_in equal to zero. There won't be anything to do, | |
792 | * but this is not an error situation so make sure we | |
793 | * return OK instead of BUF_ERROR at next call of deflate: | |
794 | */ | |
795 | s->last_flush = -1; | |
796 | return Z_OK; | |
797 | } | |
798 | ||
799 | /* Make sure there is something to do and avoid duplicate consecutive | |
800 | * flushes. For repeated and useless calls with Z_FINISH, we keep | |
801 | * returning Z_STREAM_END instead of Z_BUF_ERROR. | |
802 | */ | |
803 | } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && | |
804 | flush != Z_FINISH) { | |
805 | ERR_RETURN(strm, Z_BUF_ERROR); | |
806 | } | |
807 | ||
808 | /* User must not provide more input after the first FINISH: */ | |
809 | if (s->status == FINISH_STATE && strm->avail_in != 0) { | |
810 | ERR_RETURN(strm, Z_BUF_ERROR); | |
811 | } | |
812 | ||
5ca28f79 L |
813 | /* Write the header */ |
814 | if (s->status == INIT_STATE) { | |
de1ab01e NC |
815 | /* zlib header */ |
816 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; | |
817 | uInt level_flags; | |
818 | ||
819 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) | |
820 | level_flags = 0; | |
821 | else if (s->level < 6) | |
822 | level_flags = 1; | |
823 | else if (s->level == 6) | |
824 | level_flags = 2; | |
5ca28f79 | 825 | else |
de1ab01e NC |
826 | level_flags = 3; |
827 | header |= (level_flags << 6); | |
828 | if (s->strstart != 0) header |= PRESET_DICT; | |
829 | header += 31 - (header % 31); | |
830 | ||
831 | putShortMSB(s, header); | |
5ca28f79 | 832 | |
de1ab01e NC |
833 | /* Save the adler32 of the preset dictionary: */ |
834 | if (s->strstart != 0) { | |
835 | putShortMSB(s, (uInt)(strm->adler >> 16)); | |
836 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
837 | } | |
838 | strm->adler = adler32(0L, Z_NULL, 0); | |
839 | s->status = BUSY_STATE; | |
840 | ||
841 | /* Compression must start with an empty pending buffer */ | |
842 | flush_pending(strm); | |
843 | if (s->pending != 0) { | |
844 | s->last_flush = -1; | |
845 | return Z_OK; | |
846 | } | |
847 | } | |
848 | #ifdef GZIP | |
849 | if (s->status == GZIP_STATE) { | |
850 | /* gzip header */ | |
851 | strm->adler = crc32(0L, Z_NULL, 0); | |
852 | put_byte(s, 31); | |
853 | put_byte(s, 139); | |
854 | put_byte(s, 8); | |
855 | if (s->gzhead == Z_NULL) { | |
856 | put_byte(s, 0); | |
857 | put_byte(s, 0); | |
858 | put_byte(s, 0); | |
859 | put_byte(s, 0); | |
860 | put_byte(s, 0); | |
861 | put_byte(s, s->level == 9 ? 2 : | |
862 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
863 | 4 : 0)); | |
864 | put_byte(s, OS_CODE); | |
5ca28f79 | 865 | s->status = BUSY_STATE; |
5ca28f79 | 866 | |
de1ab01e NC |
867 | /* Compression must start with an empty pending buffer */ |
868 | flush_pending(strm); | |
869 | if (s->pending != 0) { | |
870 | s->last_flush = -1; | |
871 | return Z_OK; | |
872 | } | |
873 | } | |
874 | else { | |
875 | put_byte(s, (s->gzhead->text ? 1 : 0) + | |
876 | (s->gzhead->hcrc ? 2 : 0) + | |
877 | (s->gzhead->extra == Z_NULL ? 0 : 4) + | |
878 | (s->gzhead->name == Z_NULL ? 0 : 8) + | |
879 | (s->gzhead->comment == Z_NULL ? 0 : 16) | |
880 | ); | |
881 | put_byte(s, (Byte)(s->gzhead->time & 0xff)); | |
882 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); | |
883 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); | |
884 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); | |
885 | put_byte(s, s->level == 9 ? 2 : | |
886 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
887 | 4 : 0)); | |
888 | put_byte(s, s->gzhead->os & 0xff); | |
889 | if (s->gzhead->extra != Z_NULL) { | |
890 | put_byte(s, s->gzhead->extra_len & 0xff); | |
891 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); | |
5ca28f79 | 892 | } |
de1ab01e NC |
893 | if (s->gzhead->hcrc) |
894 | strm->adler = crc32(strm->adler, s->pending_buf, | |
895 | s->pending); | |
896 | s->gzindex = 0; | |
897 | s->status = EXTRA_STATE; | |
5ca28f79 L |
898 | } |
899 | } | |
5ca28f79 L |
900 | if (s->status == EXTRA_STATE) { |
901 | if (s->gzhead->extra != Z_NULL) { | |
de1ab01e NC |
902 | ulg beg = s->pending; /* start of bytes to update crc */ |
903 | uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex; | |
904 | while (s->pending + left > s->pending_buf_size) { | |
905 | uInt copy = s->pending_buf_size - s->pending; | |
906 | zmemcpy(s->pending_buf + s->pending, | |
907 | s->gzhead->extra + s->gzindex, copy); | |
908 | s->pending = s->pending_buf_size; | |
909 | HCRC_UPDATE(beg); | |
910 | s->gzindex += copy; | |
911 | flush_pending(strm); | |
912 | if (s->pending != 0) { | |
913 | s->last_flush = -1; | |
914 | return Z_OK; | |
5ca28f79 | 915 | } |
de1ab01e NC |
916 | beg = 0; |
917 | left -= copy; | |
5ca28f79 | 918 | } |
de1ab01e NC |
919 | zmemcpy(s->pending_buf + s->pending, |
920 | s->gzhead->extra + s->gzindex, left); | |
921 | s->pending += left; | |
922 | HCRC_UPDATE(beg); | |
923 | s->gzindex = 0; | |
5ca28f79 | 924 | } |
de1ab01e | 925 | s->status = NAME_STATE; |
5ca28f79 L |
926 | } |
927 | if (s->status == NAME_STATE) { | |
928 | if (s->gzhead->name != Z_NULL) { | |
de1ab01e | 929 | ulg beg = s->pending; /* start of bytes to update crc */ |
5ca28f79 | 930 | int val; |
5ca28f79 L |
931 | do { |
932 | if (s->pending == s->pending_buf_size) { | |
de1ab01e | 933 | HCRC_UPDATE(beg); |
5ca28f79 | 934 | flush_pending(strm); |
de1ab01e NC |
935 | if (s->pending != 0) { |
936 | s->last_flush = -1; | |
937 | return Z_OK; | |
5ca28f79 | 938 | } |
de1ab01e | 939 | beg = 0; |
5ca28f79 L |
940 | } |
941 | val = s->gzhead->name[s->gzindex++]; | |
942 | put_byte(s, val); | |
943 | } while (val != 0); | |
de1ab01e NC |
944 | HCRC_UPDATE(beg); |
945 | s->gzindex = 0; | |
5ca28f79 | 946 | } |
de1ab01e | 947 | s->status = COMMENT_STATE; |
5ca28f79 L |
948 | } |
949 | if (s->status == COMMENT_STATE) { | |
950 | if (s->gzhead->comment != Z_NULL) { | |
de1ab01e | 951 | ulg beg = s->pending; /* start of bytes to update crc */ |
5ca28f79 | 952 | int val; |
5ca28f79 L |
953 | do { |
954 | if (s->pending == s->pending_buf_size) { | |
de1ab01e | 955 | HCRC_UPDATE(beg); |
5ca28f79 | 956 | flush_pending(strm); |
de1ab01e NC |
957 | if (s->pending != 0) { |
958 | s->last_flush = -1; | |
959 | return Z_OK; | |
5ca28f79 | 960 | } |
de1ab01e | 961 | beg = 0; |
5ca28f79 L |
962 | } |
963 | val = s->gzhead->comment[s->gzindex++]; | |
964 | put_byte(s, val); | |
965 | } while (val != 0); | |
de1ab01e | 966 | HCRC_UPDATE(beg); |
5ca28f79 | 967 | } |
de1ab01e | 968 | s->status = HCRC_STATE; |
5ca28f79 L |
969 | } |
970 | if (s->status == HCRC_STATE) { | |
971 | if (s->gzhead->hcrc) { | |
de1ab01e | 972 | if (s->pending + 2 > s->pending_buf_size) { |
5ca28f79 | 973 | flush_pending(strm); |
de1ab01e NC |
974 | if (s->pending != 0) { |
975 | s->last_flush = -1; | |
976 | return Z_OK; | |
977 | } | |
5ca28f79 | 978 | } |
de1ab01e NC |
979 | put_byte(s, (Byte)(strm->adler & 0xff)); |
980 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
981 | strm->adler = crc32(0L, Z_NULL, 0); | |
5ca28f79 | 982 | } |
de1ab01e | 983 | s->status = BUSY_STATE; |
5ca28f79 | 984 | |
de1ab01e | 985 | /* Compression must start with an empty pending buffer */ |
5ca28f79 | 986 | flush_pending(strm); |
de1ab01e | 987 | if (s->pending != 0) { |
5ca28f79 L |
988 | s->last_flush = -1; |
989 | return Z_OK; | |
990 | } | |
5ca28f79 | 991 | } |
de1ab01e | 992 | #endif |
5ca28f79 L |
993 | |
994 | /* Start a new block or continue the current one. | |
995 | */ | |
996 | if (strm->avail_in != 0 || s->lookahead != 0 || | |
997 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { | |
998 | block_state bstate; | |
999 | ||
de1ab01e NC |
1000 | bstate = s->level == 0 ? deflate_stored(s, flush) : |
1001 | s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : | |
1002 | s->strategy == Z_RLE ? deflate_rle(s, flush) : | |
1003 | (*(configuration_table[s->level].func))(s, flush); | |
5ca28f79 L |
1004 | |
1005 | if (bstate == finish_started || bstate == finish_done) { | |
1006 | s->status = FINISH_STATE; | |
1007 | } | |
1008 | if (bstate == need_more || bstate == finish_started) { | |
1009 | if (strm->avail_out == 0) { | |
1010 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ | |
1011 | } | |
1012 | return Z_OK; | |
1013 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call | |
1014 | * of deflate should use the same flush parameter to make sure | |
1015 | * that the flush is complete. So we don't have to output an | |
1016 | * empty block here, this will be done at next call. This also | |
1017 | * ensures that for a very small output buffer, we emit at most | |
1018 | * one empty block. | |
1019 | */ | |
1020 | } | |
1021 | if (bstate == block_done) { | |
1022 | if (flush == Z_PARTIAL_FLUSH) { | |
1023 | _tr_align(s); | |
1024 | } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ | |
1025 | _tr_stored_block(s, (char*)0, 0L, 0); | |
1026 | /* For a full flush, this empty block will be recognized | |
1027 | * as a special marker by inflate_sync(). | |
1028 | */ | |
1029 | if (flush == Z_FULL_FLUSH) { | |
1030 | CLEAR_HASH(s); /* forget history */ | |
1031 | if (s->lookahead == 0) { | |
1032 | s->strstart = 0; | |
1033 | s->block_start = 0L; | |
1034 | s->insert = 0; | |
1035 | } | |
1036 | } | |
1037 | } | |
1038 | flush_pending(strm); | |
1039 | if (strm->avail_out == 0) { | |
1040 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ | |
1041 | return Z_OK; | |
1042 | } | |
1043 | } | |
1044 | } | |
5ca28f79 L |
1045 | |
1046 | if (flush != Z_FINISH) return Z_OK; | |
1047 | if (s->wrap <= 0) return Z_STREAM_END; | |
1048 | ||
1049 | /* Write the trailer */ | |
1050 | #ifdef GZIP | |
1051 | if (s->wrap == 2) { | |
1052 | put_byte(s, (Byte)(strm->adler & 0xff)); | |
1053 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
1054 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); | |
1055 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); | |
1056 | put_byte(s, (Byte)(strm->total_in & 0xff)); | |
1057 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); | |
1058 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); | |
1059 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); | |
1060 | } | |
1061 | else | |
1062 | #endif | |
1063 | { | |
1064 | putShortMSB(s, (uInt)(strm->adler >> 16)); | |
1065 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
1066 | } | |
1067 | flush_pending(strm); | |
1068 | /* If avail_out is zero, the application will call deflate again | |
1069 | * to flush the rest. | |
1070 | */ | |
1071 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ | |
1072 | return s->pending != 0 ? Z_OK : Z_STREAM_END; | |
1073 | } | |
1074 | ||
1075 | /* ========================================================================= */ | |
1076 | int ZEXPORT deflateEnd (strm) | |
1077 | z_streamp strm; | |
1078 | { | |
1079 | int status; | |
1080 | ||
de1ab01e | 1081 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
1082 | |
1083 | status = strm->state->status; | |
5ca28f79 L |
1084 | |
1085 | /* Deallocate in reverse order of allocations: */ | |
1086 | TRY_FREE(strm, strm->state->pending_buf); | |
1087 | TRY_FREE(strm, strm->state->head); | |
1088 | TRY_FREE(strm, strm->state->prev); | |
1089 | TRY_FREE(strm, strm->state->window); | |
1090 | ||
1091 | ZFREE(strm, strm->state); | |
1092 | strm->state = Z_NULL; | |
1093 | ||
1094 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; | |
1095 | } | |
1096 | ||
1097 | /* ========================================================================= | |
1098 | * Copy the source state to the destination state. | |
1099 | * To simplify the source, this is not supported for 16-bit MSDOS (which | |
1100 | * doesn't have enough memory anyway to duplicate compression states). | |
1101 | */ | |
1102 | int ZEXPORT deflateCopy (dest, source) | |
1103 | z_streamp dest; | |
1104 | z_streamp source; | |
1105 | { | |
1106 | #ifdef MAXSEG_64K | |
1107 | return Z_STREAM_ERROR; | |
1108 | #else | |
1109 | deflate_state *ds; | |
1110 | deflate_state *ss; | |
1111 | ushf *overlay; | |
1112 | ||
1113 | ||
de1ab01e | 1114 | if (deflateStateCheck(source) || dest == Z_NULL) { |
5ca28f79 L |
1115 | return Z_STREAM_ERROR; |
1116 | } | |
1117 | ||
1118 | ss = source->state; | |
1119 | ||
1120 | zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); | |
1121 | ||
1122 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); | |
1123 | if (ds == Z_NULL) return Z_MEM_ERROR; | |
1124 | dest->state = (struct internal_state FAR *) ds; | |
1125 | zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state)); | |
1126 | ds->strm = dest; | |
1127 | ||
1128 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); | |
1129 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); | |
1130 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); | |
1131 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); | |
1132 | ds->pending_buf = (uchf *) overlay; | |
1133 | ||
1134 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || | |
1135 | ds->pending_buf == Z_NULL) { | |
1136 | deflateEnd (dest); | |
1137 | return Z_MEM_ERROR; | |
1138 | } | |
1139 | /* following zmemcpy do not work for 16-bit MSDOS */ | |
1140 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); | |
1141 | zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos)); | |
1142 | zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos)); | |
1143 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); | |
1144 | ||
1145 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); | |
1146 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); | |
1147 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; | |
1148 | ||
1149 | ds->l_desc.dyn_tree = ds->dyn_ltree; | |
1150 | ds->d_desc.dyn_tree = ds->dyn_dtree; | |
1151 | ds->bl_desc.dyn_tree = ds->bl_tree; | |
1152 | ||
1153 | return Z_OK; | |
1154 | #endif /* MAXSEG_64K */ | |
1155 | } | |
1156 | ||
1157 | /* =========================================================================== | |
1158 | * Read a new buffer from the current input stream, update the adler32 | |
1159 | * and total number of bytes read. All deflate() input goes through | |
1160 | * this function so some applications may wish to modify it to avoid | |
1161 | * allocating a large strm->next_in buffer and copying from it. | |
1162 | * (See also flush_pending()). | |
1163 | */ | |
de1ab01e | 1164 | local unsigned read_buf(strm, buf, size) |
5ca28f79 L |
1165 | z_streamp strm; |
1166 | Bytef *buf; | |
1167 | unsigned size; | |
1168 | { | |
1169 | unsigned len = strm->avail_in; | |
1170 | ||
1171 | if (len > size) len = size; | |
1172 | if (len == 0) return 0; | |
1173 | ||
1174 | strm->avail_in -= len; | |
1175 | ||
1176 | zmemcpy(buf, strm->next_in, len); | |
1177 | if (strm->state->wrap == 1) { | |
1178 | strm->adler = adler32(strm->adler, buf, len); | |
1179 | } | |
1180 | #ifdef GZIP | |
1181 | else if (strm->state->wrap == 2) { | |
1182 | strm->adler = crc32(strm->adler, buf, len); | |
1183 | } | |
1184 | #endif | |
1185 | strm->next_in += len; | |
1186 | strm->total_in += len; | |
1187 | ||
de1ab01e | 1188 | return len; |
5ca28f79 L |
1189 | } |
1190 | ||
1191 | /* =========================================================================== | |
1192 | * Initialize the "longest match" routines for a new zlib stream | |
1193 | */ | |
1194 | local void lm_init (s) | |
1195 | deflate_state *s; | |
1196 | { | |
1197 | s->window_size = (ulg)2L*s->w_size; | |
1198 | ||
1199 | CLEAR_HASH(s); | |
1200 | ||
1201 | /* Set the default configuration parameters: | |
1202 | */ | |
1203 | s->max_lazy_match = configuration_table[s->level].max_lazy; | |
1204 | s->good_match = configuration_table[s->level].good_length; | |
1205 | s->nice_match = configuration_table[s->level].nice_length; | |
1206 | s->max_chain_length = configuration_table[s->level].max_chain; | |
1207 | ||
1208 | s->strstart = 0; | |
1209 | s->block_start = 0L; | |
1210 | s->lookahead = 0; | |
1211 | s->insert = 0; | |
1212 | s->match_length = s->prev_length = MIN_MATCH-1; | |
1213 | s->match_available = 0; | |
1214 | s->ins_h = 0; | |
1215 | #ifndef FASTEST | |
1216 | #ifdef ASMV | |
1217 | match_init(); /* initialize the asm code */ | |
1218 | #endif | |
1219 | #endif | |
1220 | } | |
1221 | ||
1222 | #ifndef FASTEST | |
1223 | /* =========================================================================== | |
1224 | * Set match_start to the longest match starting at the given string and | |
1225 | * return its length. Matches shorter or equal to prev_length are discarded, | |
1226 | * in which case the result is equal to prev_length and match_start is | |
1227 | * garbage. | |
1228 | * IN assertions: cur_match is the head of the hash chain for the current | |
1229 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | |
1230 | * OUT assertion: the match length is not greater than s->lookahead. | |
1231 | */ | |
1232 | #ifndef ASMV | |
1233 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or | |
1234 | * match.S. The code will be functionally equivalent. | |
1235 | */ | |
1236 | local uInt longest_match(s, cur_match) | |
1237 | deflate_state *s; | |
1238 | IPos cur_match; /* current match */ | |
1239 | { | |
1240 | unsigned chain_length = s->max_chain_length;/* max hash chain length */ | |
1241 | register Bytef *scan = s->window + s->strstart; /* current string */ | |
de1ab01e | 1242 | register Bytef *match; /* matched string */ |
5ca28f79 | 1243 | register int len; /* length of current match */ |
de1ab01e | 1244 | int best_len = (int)s->prev_length; /* best match length so far */ |
5ca28f79 L |
1245 | int nice_match = s->nice_match; /* stop if match long enough */ |
1246 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | |
1247 | s->strstart - (IPos)MAX_DIST(s) : NIL; | |
1248 | /* Stop when cur_match becomes <= limit. To simplify the code, | |
1249 | * we prevent matches with the string of window index 0. | |
1250 | */ | |
1251 | Posf *prev = s->prev; | |
1252 | uInt wmask = s->w_mask; | |
1253 | ||
1254 | #ifdef UNALIGNED_OK | |
1255 | /* Compare two bytes at a time. Note: this is not always beneficial. | |
1256 | * Try with and without -DUNALIGNED_OK to check. | |
1257 | */ | |
1258 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; | |
1259 | register ush scan_start = *(ushf*)scan; | |
1260 | register ush scan_end = *(ushf*)(scan+best_len-1); | |
1261 | #else | |
1262 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1263 | register Byte scan_end1 = scan[best_len-1]; | |
1264 | register Byte scan_end = scan[best_len]; | |
1265 | #endif | |
1266 | ||
1267 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1268 | * It is easy to get rid of this optimization if necessary. | |
1269 | */ | |
1270 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1271 | ||
1272 | /* Do not waste too much time if we already have a good match: */ | |
1273 | if (s->prev_length >= s->good_match) { | |
1274 | chain_length >>= 2; | |
1275 | } | |
1276 | /* Do not look for matches beyond the end of the input. This is necessary | |
1277 | * to make deflate deterministic. | |
1278 | */ | |
de1ab01e | 1279 | if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead; |
5ca28f79 L |
1280 | |
1281 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1282 | ||
1283 | do { | |
1284 | Assert(cur_match < s->strstart, "no future"); | |
1285 | match = s->window + cur_match; | |
1286 | ||
1287 | /* Skip to next match if the match length cannot increase | |
1288 | * or if the match length is less than 2. Note that the checks below | |
1289 | * for insufficient lookahead only occur occasionally for performance | |
1290 | * reasons. Therefore uninitialized memory will be accessed, and | |
1291 | * conditional jumps will be made that depend on those values. | |
1292 | * However the length of the match is limited to the lookahead, so | |
1293 | * the output of deflate is not affected by the uninitialized values. | |
1294 | */ | |
1295 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) | |
1296 | /* This code assumes sizeof(unsigned short) == 2. Do not use | |
1297 | * UNALIGNED_OK if your compiler uses a different size. | |
1298 | */ | |
1299 | if (*(ushf*)(match+best_len-1) != scan_end || | |
1300 | *(ushf*)match != scan_start) continue; | |
1301 | ||
1302 | /* It is not necessary to compare scan[2] and match[2] since they are | |
1303 | * always equal when the other bytes match, given that the hash keys | |
1304 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at | |
1305 | * strstart+3, +5, ... up to strstart+257. We check for insufficient | |
1306 | * lookahead only every 4th comparison; the 128th check will be made | |
1307 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is | |
1308 | * necessary to put more guard bytes at the end of the window, or | |
1309 | * to check more often for insufficient lookahead. | |
1310 | */ | |
1311 | Assert(scan[2] == match[2], "scan[2]?"); | |
1312 | scan++, match++; | |
1313 | do { | |
1314 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1315 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1316 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1317 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
1318 | scan < strend); | |
1319 | /* The funny "do {}" generates better code on most compilers */ | |
1320 | ||
1321 | /* Here, scan <= window+strstart+257 */ | |
1322 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1323 | if (*scan == *match) scan++; | |
1324 | ||
1325 | len = (MAX_MATCH - 1) - (int)(strend-scan); | |
1326 | scan = strend - (MAX_MATCH-1); | |
1327 | ||
1328 | #else /* UNALIGNED_OK */ | |
1329 | ||
1330 | if (match[best_len] != scan_end || | |
1331 | match[best_len-1] != scan_end1 || | |
1332 | *match != *scan || | |
1333 | *++match != scan[1]) continue; | |
1334 | ||
1335 | /* The check at best_len-1 can be removed because it will be made | |
1336 | * again later. (This heuristic is not always a win.) | |
1337 | * It is not necessary to compare scan[2] and match[2] since they | |
1338 | * are always equal when the other bytes match, given that | |
1339 | * the hash keys are equal and that HASH_BITS >= 8. | |
1340 | */ | |
1341 | scan += 2, match++; | |
1342 | Assert(*scan == *match, "match[2]?"); | |
1343 | ||
1344 | /* We check for insufficient lookahead only every 8th comparison; | |
1345 | * the 256th check will be made at strstart+258. | |
1346 | */ | |
1347 | do { | |
1348 | } while (*++scan == *++match && *++scan == *++match && | |
1349 | *++scan == *++match && *++scan == *++match && | |
1350 | *++scan == *++match && *++scan == *++match && | |
1351 | *++scan == *++match && *++scan == *++match && | |
1352 | scan < strend); | |
1353 | ||
1354 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1355 | ||
1356 | len = MAX_MATCH - (int)(strend - scan); | |
1357 | scan = strend - MAX_MATCH; | |
1358 | ||
1359 | #endif /* UNALIGNED_OK */ | |
1360 | ||
1361 | if (len > best_len) { | |
1362 | s->match_start = cur_match; | |
1363 | best_len = len; | |
1364 | if (len >= nice_match) break; | |
1365 | #ifdef UNALIGNED_OK | |
1366 | scan_end = *(ushf*)(scan+best_len-1); | |
1367 | #else | |
1368 | scan_end1 = scan[best_len-1]; | |
1369 | scan_end = scan[best_len]; | |
1370 | #endif | |
1371 | } | |
1372 | } while ((cur_match = prev[cur_match & wmask]) > limit | |
1373 | && --chain_length != 0); | |
1374 | ||
1375 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | |
1376 | return s->lookahead; | |
1377 | } | |
1378 | #endif /* ASMV */ | |
1379 | ||
1380 | #else /* FASTEST */ | |
1381 | ||
1382 | /* --------------------------------------------------------------------------- | |
1383 | * Optimized version for FASTEST only | |
1384 | */ | |
1385 | local uInt longest_match(s, cur_match) | |
1386 | deflate_state *s; | |
1387 | IPos cur_match; /* current match */ | |
1388 | { | |
1389 | register Bytef *scan = s->window + s->strstart; /* current string */ | |
1390 | register Bytef *match; /* matched string */ | |
1391 | register int len; /* length of current match */ | |
1392 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
1393 | ||
1394 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
1395 | * It is easy to get rid of this optimization if necessary. | |
1396 | */ | |
1397 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
1398 | ||
1399 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
1400 | ||
1401 | Assert(cur_match < s->strstart, "no future"); | |
1402 | ||
1403 | match = s->window + cur_match; | |
1404 | ||
1405 | /* Return failure if the match length is less than 2: | |
1406 | */ | |
1407 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; | |
1408 | ||
1409 | /* The check at best_len-1 can be removed because it will be made | |
1410 | * again later. (This heuristic is not always a win.) | |
1411 | * It is not necessary to compare scan[2] and match[2] since they | |
1412 | * are always equal when the other bytes match, given that | |
1413 | * the hash keys are equal and that HASH_BITS >= 8. | |
1414 | */ | |
1415 | scan += 2, match += 2; | |
1416 | Assert(*scan == *match, "match[2]?"); | |
1417 | ||
1418 | /* We check for insufficient lookahead only every 8th comparison; | |
1419 | * the 256th check will be made at strstart+258. | |
1420 | */ | |
1421 | do { | |
1422 | } while (*++scan == *++match && *++scan == *++match && | |
1423 | *++scan == *++match && *++scan == *++match && | |
1424 | *++scan == *++match && *++scan == *++match && | |
1425 | *++scan == *++match && *++scan == *++match && | |
1426 | scan < strend); | |
1427 | ||
1428 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
1429 | ||
1430 | len = MAX_MATCH - (int)(strend - scan); | |
1431 | ||
1432 | if (len < MIN_MATCH) return MIN_MATCH - 1; | |
1433 | ||
1434 | s->match_start = cur_match; | |
1435 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; | |
1436 | } | |
1437 | ||
1438 | #endif /* FASTEST */ | |
1439 | ||
de1ab01e NC |
1440 | #ifdef ZLIB_DEBUG |
1441 | ||
1442 | #define EQUAL 0 | |
1443 | /* result of memcmp for equal strings */ | |
1444 | ||
5ca28f79 L |
1445 | /* =========================================================================== |
1446 | * Check that the match at match_start is indeed a match. | |
1447 | */ | |
1448 | local void check_match(s, start, match, length) | |
1449 | deflate_state *s; | |
1450 | IPos start, match; | |
1451 | int length; | |
1452 | { | |
1453 | /* check that the match is indeed a match */ | |
1454 | if (zmemcmp(s->window + match, | |
1455 | s->window + start, length) != EQUAL) { | |
1456 | fprintf(stderr, " start %u, match %u, length %d\n", | |
1457 | start, match, length); | |
1458 | do { | |
1459 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); | |
1460 | } while (--length != 0); | |
1461 | z_error("invalid match"); | |
1462 | } | |
1463 | if (z_verbose > 1) { | |
1464 | fprintf(stderr,"\\[%d,%d]", start-match, length); | |
1465 | do { putc(s->window[start++], stderr); } while (--length != 0); | |
1466 | } | |
1467 | } | |
1468 | #else | |
1469 | # define check_match(s, start, match, length) | |
de1ab01e | 1470 | #endif /* ZLIB_DEBUG */ |
5ca28f79 L |
1471 | |
1472 | /* =========================================================================== | |
1473 | * Fill the window when the lookahead becomes insufficient. | |
1474 | * Updates strstart and lookahead. | |
1475 | * | |
1476 | * IN assertion: lookahead < MIN_LOOKAHEAD | |
1477 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD | |
1478 | * At least one byte has been read, or avail_in == 0; reads are | |
1479 | * performed for at least two bytes (required for the zip translate_eol | |
1480 | * option -- not supported here). | |
1481 | */ | |
1482 | local void fill_window(s) | |
1483 | deflate_state *s; | |
1484 | { | |
de1ab01e | 1485 | unsigned n; |
5ca28f79 L |
1486 | unsigned more; /* Amount of free space at the end of the window. */ |
1487 | uInt wsize = s->w_size; | |
1488 | ||
1489 | Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); | |
1490 | ||
1491 | do { | |
1492 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); | |
1493 | ||
1494 | /* Deal with !@#$% 64K limit: */ | |
1495 | if (sizeof(int) <= 2) { | |
1496 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) { | |
1497 | more = wsize; | |
1498 | ||
1499 | } else if (more == (unsigned)(-1)) { | |
1500 | /* Very unlikely, but possible on 16 bit machine if | |
1501 | * strstart == 0 && lookahead == 1 (input done a byte at time) | |
1502 | */ | |
1503 | more--; | |
1504 | } | |
1505 | } | |
1506 | ||
1507 | /* If the window is almost full and there is insufficient lookahead, | |
1508 | * move the upper half to the lower one to make room in the upper half. | |
1509 | */ | |
1510 | if (s->strstart >= wsize+MAX_DIST(s)) { | |
1511 | ||
de1ab01e | 1512 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more); |
5ca28f79 L |
1513 | s->match_start -= wsize; |
1514 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ | |
1515 | s->block_start -= (long) wsize; | |
de1ab01e | 1516 | slide_hash(s); |
5ca28f79 L |
1517 | more += wsize; |
1518 | } | |
1519 | if (s->strm->avail_in == 0) break; | |
1520 | ||
1521 | /* If there was no sliding: | |
1522 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && | |
1523 | * more == window_size - lookahead - strstart | |
1524 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) | |
1525 | * => more >= window_size - 2*WSIZE + 2 | |
1526 | * In the BIG_MEM or MMAP case (not yet supported), | |
1527 | * window_size == input_size + MIN_LOOKAHEAD && | |
1528 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. | |
1529 | * Otherwise, window_size == 2*WSIZE so more >= 2. | |
1530 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2. | |
1531 | */ | |
1532 | Assert(more >= 2, "more < 2"); | |
1533 | ||
1534 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); | |
1535 | s->lookahead += n; | |
1536 | ||
1537 | /* Initialize the hash value now that we have some input: */ | |
1538 | if (s->lookahead + s->insert >= MIN_MATCH) { | |
1539 | uInt str = s->strstart - s->insert; | |
1540 | s->ins_h = s->window[str]; | |
1541 | UPDATE_HASH(s, s->ins_h, s->window[str + 1]); | |
1542 | #if MIN_MATCH != 3 | |
1543 | Call UPDATE_HASH() MIN_MATCH-3 more times | |
1544 | #endif | |
1545 | while (s->insert) { | |
1546 | UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); | |
1547 | #ifndef FASTEST | |
1548 | s->prev[str & s->w_mask] = s->head[s->ins_h]; | |
1549 | #endif | |
1550 | s->head[s->ins_h] = (Pos)str; | |
1551 | str++; | |
1552 | s->insert--; | |
1553 | if (s->lookahead + s->insert < MIN_MATCH) | |
1554 | break; | |
1555 | } | |
1556 | } | |
1557 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, | |
1558 | * but this is not important since only literal bytes will be emitted. | |
1559 | */ | |
1560 | ||
1561 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); | |
1562 | ||
1563 | /* If the WIN_INIT bytes after the end of the current data have never been | |
1564 | * written, then zero those bytes in order to avoid memory check reports of | |
1565 | * the use of uninitialized (or uninitialised as Julian writes) bytes by | |
1566 | * the longest match routines. Update the high water mark for the next | |
1567 | * time through here. WIN_INIT is set to MAX_MATCH since the longest match | |
1568 | * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. | |
1569 | */ | |
1570 | if (s->high_water < s->window_size) { | |
1571 | ulg curr = s->strstart + (ulg)(s->lookahead); | |
1572 | ulg init; | |
1573 | ||
1574 | if (s->high_water < curr) { | |
1575 | /* Previous high water mark below current data -- zero WIN_INIT | |
1576 | * bytes or up to end of window, whichever is less. | |
1577 | */ | |
1578 | init = s->window_size - curr; | |
1579 | if (init > WIN_INIT) | |
1580 | init = WIN_INIT; | |
1581 | zmemzero(s->window + curr, (unsigned)init); | |
1582 | s->high_water = curr + init; | |
1583 | } | |
1584 | else if (s->high_water < (ulg)curr + WIN_INIT) { | |
1585 | /* High water mark at or above current data, but below current data | |
1586 | * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up | |
1587 | * to end of window, whichever is less. | |
1588 | */ | |
1589 | init = (ulg)curr + WIN_INIT - s->high_water; | |
1590 | if (init > s->window_size - s->high_water) | |
1591 | init = s->window_size - s->high_water; | |
1592 | zmemzero(s->window + s->high_water, (unsigned)init); | |
1593 | s->high_water += init; | |
1594 | } | |
1595 | } | |
1596 | ||
1597 | Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, | |
1598 | "not enough room for search"); | |
1599 | } | |
1600 | ||
1601 | /* =========================================================================== | |
1602 | * Flush the current block, with given end-of-file flag. | |
1603 | * IN assertion: strstart is set to the end of the current match. | |
1604 | */ | |
1605 | #define FLUSH_BLOCK_ONLY(s, last) { \ | |
1606 | _tr_flush_block(s, (s->block_start >= 0L ? \ | |
1607 | (charf *)&s->window[(unsigned)s->block_start] : \ | |
1608 | (charf *)Z_NULL), \ | |
1609 | (ulg)((long)s->strstart - s->block_start), \ | |
1610 | (last)); \ | |
1611 | s->block_start = s->strstart; \ | |
1612 | flush_pending(s->strm); \ | |
1613 | Tracev((stderr,"[FLUSH]")); \ | |
1614 | } | |
1615 | ||
1616 | /* Same but force premature exit if necessary. */ | |
1617 | #define FLUSH_BLOCK(s, last) { \ | |
1618 | FLUSH_BLOCK_ONLY(s, last); \ | |
1619 | if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ | |
1620 | } | |
1621 | ||
de1ab01e NC |
1622 | /* Maximum stored block length in deflate format (not including header). */ |
1623 | #define MAX_STORED 65535 | |
1624 | ||
1625 | /* Minimum of a and b. */ | |
1626 | #define MIN(a, b) ((a) > (b) ? (b) : (a)) | |
1627 | ||
5ca28f79 L |
1628 | /* =========================================================================== |
1629 | * Copy without compression as much as possible from the input stream, return | |
1630 | * the current block state. | |
de1ab01e NC |
1631 | * |
1632 | * In case deflateParams() is used to later switch to a non-zero compression | |
1633 | * level, s->matches (otherwise unused when storing) keeps track of the number | |
1634 | * of hash table slides to perform. If s->matches is 1, then one hash table | |
1635 | * slide will be done when switching. If s->matches is 2, the maximum value | |
1636 | * allowed here, then the hash table will be cleared, since two or more slides | |
1637 | * is the same as a clear. | |
1638 | * | |
1639 | * deflate_stored() is written to minimize the number of times an input byte is | |
1640 | * copied. It is most efficient with large input and output buffers, which | |
1641 | * maximizes the opportunites to have a single copy from next_in to next_out. | |
5ca28f79 L |
1642 | */ |
1643 | local block_state deflate_stored(s, flush) | |
1644 | deflate_state *s; | |
1645 | int flush; | |
1646 | { | |
de1ab01e NC |
1647 | /* Smallest worthy block size when not flushing or finishing. By default |
1648 | * this is 32K. This can be as small as 507 bytes for memLevel == 1. For | |
1649 | * large input and output buffers, the stored block size will be larger. | |
5ca28f79 | 1650 | */ |
de1ab01e | 1651 | unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size); |
5ca28f79 | 1652 | |
de1ab01e NC |
1653 | /* Copy as many min_block or larger stored blocks directly to next_out as |
1654 | * possible. If flushing, copy the remaining available input to next_out as | |
1655 | * stored blocks, if there is enough space. | |
1656 | */ | |
1657 | unsigned len, left, have, last = 0; | |
1658 | unsigned used = s->strm->avail_in; | |
1659 | do { | |
1660 | /* Set len to the maximum size block that we can copy directly with the | |
1661 | * available input data and output space. Set left to how much of that | |
1662 | * would be copied from what's left in the window. | |
1663 | */ | |
1664 | len = MAX_STORED; /* maximum deflate stored block length */ | |
1665 | have = (s->bi_valid + 42) >> 3; /* number of header bytes */ | |
1666 | if (s->strm->avail_out < have) /* need room for header */ | |
1667 | break; | |
1668 | /* maximum stored block length that will fit in avail_out: */ | |
1669 | have = s->strm->avail_out - have; | |
1670 | left = s->strstart - s->block_start; /* bytes left in window */ | |
1671 | if (len > (ulg)left + s->strm->avail_in) | |
1672 | len = left + s->strm->avail_in; /* limit len to the input */ | |
1673 | if (len > have) | |
1674 | len = have; /* limit len to the output */ | |
de1ab01e NC |
1675 | |
1676 | /* If the stored block would be less than min_block in length, or if | |
1677 | * unable to copy all of the available input when flushing, then try | |
1678 | * copying to the window and the pending buffer instead. Also don't | |
1679 | * write an empty block when flushing -- deflate() does that. | |
1680 | */ | |
1681 | if (len < min_block && ((len == 0 && flush != Z_FINISH) || | |
1682 | flush == Z_NO_FLUSH || | |
9c7e3b0e | 1683 | len != left + s->strm->avail_in)) |
de1ab01e | 1684 | break; |
5ca28f79 | 1685 | |
de1ab01e NC |
1686 | /* Make a dummy stored block in pending to get the header bytes, |
1687 | * including any pending bits. This also updates the debugging counts. | |
1688 | */ | |
9c7e3b0e | 1689 | last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0; |
de1ab01e NC |
1690 | _tr_stored_block(s, (char *)0, 0L, last); |
1691 | ||
1692 | /* Replace the lengths in the dummy stored block with len. */ | |
1693 | s->pending_buf[s->pending - 4] = len; | |
1694 | s->pending_buf[s->pending - 3] = len >> 8; | |
1695 | s->pending_buf[s->pending - 2] = ~len; | |
1696 | s->pending_buf[s->pending - 1] = ~len >> 8; | |
1697 | ||
1698 | /* Write the stored block header bytes. */ | |
1699 | flush_pending(s->strm); | |
1700 | ||
de1ab01e | 1701 | #ifdef ZLIB_DEBUG |
9c7e3b0e | 1702 | /* Update debugging counts for the data about to be copied. */ |
de1ab01e NC |
1703 | s->compressed_len += len << 3; |
1704 | s->bits_sent += len << 3; | |
1705 | #endif | |
5ca28f79 | 1706 | |
de1ab01e NC |
1707 | /* Copy uncompressed bytes from the window to next_out. */ |
1708 | if (left) { | |
9c7e3b0e NC |
1709 | if (left > len) |
1710 | left = len; | |
de1ab01e NC |
1711 | zmemcpy(s->strm->next_out, s->window + s->block_start, left); |
1712 | s->strm->next_out += left; | |
1713 | s->strm->avail_out -= left; | |
1714 | s->strm->total_out += left; | |
1715 | s->block_start += left; | |
1716 | len -= left; | |
5ca28f79 | 1717 | } |
de1ab01e NC |
1718 | |
1719 | /* Copy uncompressed bytes directly from next_in to next_out, updating | |
1720 | * the check value. | |
1721 | */ | |
1722 | if (len) { | |
1723 | read_buf(s->strm, s->strm->next_out, len); | |
1724 | s->strm->next_out += len; | |
1725 | s->strm->avail_out -= len; | |
1726 | s->strm->total_out += len; | |
5ca28f79 | 1727 | } |
de1ab01e NC |
1728 | } while (last == 0); |
1729 | ||
1730 | /* Update the sliding window with the last s->w_size bytes of the copied | |
1731 | * data, or append all of the copied data to the existing window if less | |
1732 | * than s->w_size bytes were copied. Also update the number of bytes to | |
1733 | * insert in the hash tables, in the event that deflateParams() switches to | |
1734 | * a non-zero compression level. | |
1735 | */ | |
1736 | used -= s->strm->avail_in; /* number of input bytes directly copied */ | |
1737 | if (used) { | |
1738 | /* If any input was used, then no unused input remains in the window, | |
1739 | * therefore s->block_start == s->strstart. | |
5ca28f79 | 1740 | */ |
de1ab01e NC |
1741 | if (used >= s->w_size) { /* supplant the previous history */ |
1742 | s->matches = 2; /* clear hash */ | |
1743 | zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); | |
1744 | s->strstart = s->w_size; | |
5ca28f79 | 1745 | } |
de1ab01e NC |
1746 | else { |
1747 | if (s->window_size - s->strstart <= used) { | |
1748 | /* Slide the window down. */ | |
1749 | s->strstart -= s->w_size; | |
1750 | zmemcpy(s->window, s->window + s->w_size, s->strstart); | |
1751 | if (s->matches < 2) | |
1752 | s->matches++; /* add a pending slide_hash() */ | |
1753 | } | |
1754 | zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); | |
1755 | s->strstart += used; | |
1756 | } | |
1757 | s->block_start = s->strstart; | |
1758 | s->insert += MIN(used, s->w_size - s->insert); | |
5ca28f79 | 1759 | } |
9c7e3b0e NC |
1760 | if (s->high_water < s->strstart) |
1761 | s->high_water = s->strstart; | |
de1ab01e NC |
1762 | |
1763 | /* If the last block was written to next_out, then done. */ | |
1764 | if (last) | |
5ca28f79 | 1765 | return finish_done; |
de1ab01e NC |
1766 | |
1767 | /* If flushing and all input has been consumed, then done. */ | |
1768 | if (flush != Z_NO_FLUSH && flush != Z_FINISH && | |
1769 | s->strm->avail_in == 0 && (long)s->strstart == s->block_start) | |
1770 | return block_done; | |
1771 | ||
1772 | /* Fill the window with any remaining input. */ | |
1773 | have = s->window_size - s->strstart - 1; | |
1774 | if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { | |
1775 | /* Slide the window down. */ | |
1776 | s->block_start -= s->w_size; | |
1777 | s->strstart -= s->w_size; | |
1778 | zmemcpy(s->window, s->window + s->w_size, s->strstart); | |
1779 | if (s->matches < 2) | |
1780 | s->matches++; /* add a pending slide_hash() */ | |
1781 | have += s->w_size; /* more space now */ | |
5ca28f79 | 1782 | } |
de1ab01e NC |
1783 | if (have > s->strm->avail_in) |
1784 | have = s->strm->avail_in; | |
1785 | if (have) { | |
1786 | read_buf(s->strm, s->window + s->strstart, have); | |
1787 | s->strstart += have; | |
1788 | } | |
9c7e3b0e NC |
1789 | if (s->high_water < s->strstart) |
1790 | s->high_water = s->strstart; | |
de1ab01e NC |
1791 | |
1792 | /* There was not enough avail_out to write a complete worthy or flushed | |
1793 | * stored block to next_out. Write a stored block to pending instead, if we | |
1794 | * have enough input for a worthy block, or if flushing and there is enough | |
1795 | * room for the remaining input as a stored block in the pending buffer. | |
1796 | */ | |
1797 | have = (s->bi_valid + 42) >> 3; /* number of header bytes */ | |
1798 | /* maximum stored block length that will fit in pending: */ | |
1799 | have = MIN(s->pending_buf_size - have, MAX_STORED); | |
1800 | min_block = MIN(have, s->w_size); | |
1801 | left = s->strstart - s->block_start; | |
1802 | if (left >= min_block || | |
1803 | ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH && | |
1804 | s->strm->avail_in == 0 && left <= have)) { | |
1805 | len = MIN(left, have); | |
1806 | last = flush == Z_FINISH && s->strm->avail_in == 0 && | |
1807 | len == left ? 1 : 0; | |
1808 | _tr_stored_block(s, (charf *)s->window + s->block_start, len, last); | |
1809 | s->block_start += len; | |
1810 | flush_pending(s->strm); | |
1811 | } | |
1812 | ||
1813 | /* We've done all we can with the available input and output. */ | |
1814 | return last ? finish_started : need_more; | |
5ca28f79 L |
1815 | } |
1816 | ||
1817 | /* =========================================================================== | |
1818 | * Compress as much as possible from the input stream, return the current | |
1819 | * block state. | |
1820 | * This function does not perform lazy evaluation of matches and inserts | |
1821 | * new strings in the dictionary only for unmatched strings or for short | |
1822 | * matches. It is used only for the fast compression options. | |
1823 | */ | |
1824 | local block_state deflate_fast(s, flush) | |
1825 | deflate_state *s; | |
1826 | int flush; | |
1827 | { | |
1828 | IPos hash_head; /* head of the hash chain */ | |
1829 | int bflush; /* set if current block must be flushed */ | |
1830 | ||
1831 | for (;;) { | |
1832 | /* Make sure that we always have enough lookahead, except | |
1833 | * at the end of the input file. We need MAX_MATCH bytes | |
1834 | * for the next match, plus MIN_MATCH bytes to insert the | |
1835 | * string following the next match. | |
1836 | */ | |
1837 | if (s->lookahead < MIN_LOOKAHEAD) { | |
1838 | fill_window(s); | |
1839 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1840 | return need_more; | |
1841 | } | |
1842 | if (s->lookahead == 0) break; /* flush the current block */ | |
1843 | } | |
1844 | ||
1845 | /* Insert the string window[strstart .. strstart+2] in the | |
1846 | * dictionary, and set hash_head to the head of the hash chain: | |
1847 | */ | |
1848 | hash_head = NIL; | |
1849 | if (s->lookahead >= MIN_MATCH) { | |
1850 | INSERT_STRING(s, s->strstart, hash_head); | |
1851 | } | |
1852 | ||
1853 | /* Find the longest match, discarding those <= prev_length. | |
1854 | * At this point we have always match_length < MIN_MATCH | |
1855 | */ | |
1856 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { | |
1857 | /* To simplify the code, we prevent matches with the string | |
1858 | * of window index 0 (in particular we have to avoid a match | |
1859 | * of the string with itself at the start of the input file). | |
1860 | */ | |
1861 | s->match_length = longest_match (s, hash_head); | |
1862 | /* longest_match() sets match_start */ | |
1863 | } | |
1864 | if (s->match_length >= MIN_MATCH) { | |
1865 | check_match(s, s->strstart, s->match_start, s->match_length); | |
1866 | ||
1867 | _tr_tally_dist(s, s->strstart - s->match_start, | |
1868 | s->match_length - MIN_MATCH, bflush); | |
1869 | ||
1870 | s->lookahead -= s->match_length; | |
1871 | ||
1872 | /* Insert new strings in the hash table only if the match length | |
1873 | * is not too large. This saves time but degrades compression. | |
1874 | */ | |
1875 | #ifndef FASTEST | |
1876 | if (s->match_length <= s->max_insert_length && | |
1877 | s->lookahead >= MIN_MATCH) { | |
1878 | s->match_length--; /* string at strstart already in table */ | |
1879 | do { | |
1880 | s->strstart++; | |
1881 | INSERT_STRING(s, s->strstart, hash_head); | |
1882 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are | |
1883 | * always MIN_MATCH bytes ahead. | |
1884 | */ | |
1885 | } while (--s->match_length != 0); | |
1886 | s->strstart++; | |
1887 | } else | |
1888 | #endif | |
1889 | { | |
1890 | s->strstart += s->match_length; | |
1891 | s->match_length = 0; | |
1892 | s->ins_h = s->window[s->strstart]; | |
1893 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
1894 | #if MIN_MATCH != 3 | |
1895 | Call UPDATE_HASH() MIN_MATCH-3 more times | |
1896 | #endif | |
1897 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not | |
1898 | * matter since it will be recomputed at next deflate call. | |
1899 | */ | |
1900 | } | |
1901 | } else { | |
1902 | /* No match, output a literal byte */ | |
1903 | Tracevv((stderr,"%c", s->window[s->strstart])); | |
1904 | _tr_tally_lit (s, s->window[s->strstart], bflush); | |
1905 | s->lookahead--; | |
1906 | s->strstart++; | |
1907 | } | |
1908 | if (bflush) FLUSH_BLOCK(s, 0); | |
1909 | } | |
1910 | s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; | |
1911 | if (flush == Z_FINISH) { | |
1912 | FLUSH_BLOCK(s, 1); | |
1913 | return finish_done; | |
1914 | } | |
1915 | if (s->last_lit) | |
1916 | FLUSH_BLOCK(s, 0); | |
1917 | return block_done; | |
1918 | } | |
1919 | ||
1920 | #ifndef FASTEST | |
1921 | /* =========================================================================== | |
1922 | * Same as above, but achieves better compression. We use a lazy | |
1923 | * evaluation for matches: a match is finally adopted only if there is | |
1924 | * no better match at the next window position. | |
1925 | */ | |
1926 | local block_state deflate_slow(s, flush) | |
1927 | deflate_state *s; | |
1928 | int flush; | |
1929 | { | |
1930 | IPos hash_head; /* head of hash chain */ | |
1931 | int bflush; /* set if current block must be flushed */ | |
1932 | ||
1933 | /* Process the input block. */ | |
1934 | for (;;) { | |
1935 | /* Make sure that we always have enough lookahead, except | |
1936 | * at the end of the input file. We need MAX_MATCH bytes | |
1937 | * for the next match, plus MIN_MATCH bytes to insert the | |
1938 | * string following the next match. | |
1939 | */ | |
1940 | if (s->lookahead < MIN_LOOKAHEAD) { | |
1941 | fill_window(s); | |
1942 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
1943 | return need_more; | |
1944 | } | |
1945 | if (s->lookahead == 0) break; /* flush the current block */ | |
1946 | } | |
1947 | ||
1948 | /* Insert the string window[strstart .. strstart+2] in the | |
1949 | * dictionary, and set hash_head to the head of the hash chain: | |
1950 | */ | |
1951 | hash_head = NIL; | |
1952 | if (s->lookahead >= MIN_MATCH) { | |
1953 | INSERT_STRING(s, s->strstart, hash_head); | |
1954 | } | |
1955 | ||
1956 | /* Find the longest match, discarding those <= prev_length. | |
1957 | */ | |
1958 | s->prev_length = s->match_length, s->prev_match = s->match_start; | |
1959 | s->match_length = MIN_MATCH-1; | |
1960 | ||
1961 | if (hash_head != NIL && s->prev_length < s->max_lazy_match && | |
1962 | s->strstart - hash_head <= MAX_DIST(s)) { | |
1963 | /* To simplify the code, we prevent matches with the string | |
1964 | * of window index 0 (in particular we have to avoid a match | |
1965 | * of the string with itself at the start of the input file). | |
1966 | */ | |
1967 | s->match_length = longest_match (s, hash_head); | |
1968 | /* longest_match() sets match_start */ | |
1969 | ||
1970 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED | |
1971 | #if TOO_FAR <= 32767 | |
1972 | || (s->match_length == MIN_MATCH && | |
1973 | s->strstart - s->match_start > TOO_FAR) | |
1974 | #endif | |
1975 | )) { | |
1976 | ||
1977 | /* If prev_match is also MIN_MATCH, match_start is garbage | |
1978 | * but we will ignore the current match anyway. | |
1979 | */ | |
1980 | s->match_length = MIN_MATCH-1; | |
1981 | } | |
1982 | } | |
1983 | /* If there was a match at the previous step and the current | |
1984 | * match is not better, output the previous match: | |
1985 | */ | |
1986 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { | |
1987 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; | |
1988 | /* Do not insert strings in hash table beyond this. */ | |
1989 | ||
1990 | check_match(s, s->strstart-1, s->prev_match, s->prev_length); | |
1991 | ||
1992 | _tr_tally_dist(s, s->strstart -1 - s->prev_match, | |
1993 | s->prev_length - MIN_MATCH, bflush); | |
1994 | ||
1995 | /* Insert in hash table all strings up to the end of the match. | |
1996 | * strstart-1 and strstart are already inserted. If there is not | |
1997 | * enough lookahead, the last two strings are not inserted in | |
1998 | * the hash table. | |
1999 | */ | |
2000 | s->lookahead -= s->prev_length-1; | |
2001 | s->prev_length -= 2; | |
2002 | do { | |
2003 | if (++s->strstart <= max_insert) { | |
2004 | INSERT_STRING(s, s->strstart, hash_head); | |
2005 | } | |
2006 | } while (--s->prev_length != 0); | |
2007 | s->match_available = 0; | |
2008 | s->match_length = MIN_MATCH-1; | |
2009 | s->strstart++; | |
2010 | ||
2011 | if (bflush) FLUSH_BLOCK(s, 0); | |
2012 | ||
2013 | } else if (s->match_available) { | |
2014 | /* If there was no match at the previous position, output a | |
2015 | * single literal. If there was a match but the current match | |
2016 | * is longer, truncate the previous match to a single literal. | |
2017 | */ | |
2018 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
2019 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
2020 | if (bflush) { | |
2021 | FLUSH_BLOCK_ONLY(s, 0); | |
2022 | } | |
2023 | s->strstart++; | |
2024 | s->lookahead--; | |
2025 | if (s->strm->avail_out == 0) return need_more; | |
2026 | } else { | |
2027 | /* There is no previous match to compare with, wait for | |
2028 | * the next step to decide. | |
2029 | */ | |
2030 | s->match_available = 1; | |
2031 | s->strstart++; | |
2032 | s->lookahead--; | |
2033 | } | |
2034 | } | |
2035 | Assert (flush != Z_NO_FLUSH, "no flush?"); | |
2036 | if (s->match_available) { | |
2037 | Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
2038 | _tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
2039 | s->match_available = 0; | |
2040 | } | |
2041 | s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; | |
2042 | if (flush == Z_FINISH) { | |
2043 | FLUSH_BLOCK(s, 1); | |
2044 | return finish_done; | |
2045 | } | |
2046 | if (s->last_lit) | |
2047 | FLUSH_BLOCK(s, 0); | |
2048 | return block_done; | |
2049 | } | |
2050 | #endif /* FASTEST */ | |
2051 | ||
2052 | /* =========================================================================== | |
2053 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance | |
2054 | * one. Do not maintain a hash table. (It will be regenerated if this run of | |
2055 | * deflate switches away from Z_RLE.) | |
2056 | */ | |
2057 | local block_state deflate_rle(s, flush) | |
2058 | deflate_state *s; | |
2059 | int flush; | |
2060 | { | |
2061 | int bflush; /* set if current block must be flushed */ | |
2062 | uInt prev; /* byte at distance one to match */ | |
2063 | Bytef *scan, *strend; /* scan goes up to strend for length of run */ | |
2064 | ||
2065 | for (;;) { | |
2066 | /* Make sure that we always have enough lookahead, except | |
2067 | * at the end of the input file. We need MAX_MATCH bytes | |
2068 | * for the longest run, plus one for the unrolled loop. | |
2069 | */ | |
2070 | if (s->lookahead <= MAX_MATCH) { | |
2071 | fill_window(s); | |
2072 | if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { | |
2073 | return need_more; | |
2074 | } | |
2075 | if (s->lookahead == 0) break; /* flush the current block */ | |
2076 | } | |
2077 | ||
2078 | /* See how many times the previous byte repeats */ | |
2079 | s->match_length = 0; | |
2080 | if (s->lookahead >= MIN_MATCH && s->strstart > 0) { | |
2081 | scan = s->window + s->strstart - 1; | |
2082 | prev = *scan; | |
2083 | if (prev == *++scan && prev == *++scan && prev == *++scan) { | |
2084 | strend = s->window + s->strstart + MAX_MATCH; | |
2085 | do { | |
2086 | } while (prev == *++scan && prev == *++scan && | |
2087 | prev == *++scan && prev == *++scan && | |
2088 | prev == *++scan && prev == *++scan && | |
2089 | prev == *++scan && prev == *++scan && | |
2090 | scan < strend); | |
de1ab01e | 2091 | s->match_length = MAX_MATCH - (uInt)(strend - scan); |
5ca28f79 L |
2092 | if (s->match_length > s->lookahead) |
2093 | s->match_length = s->lookahead; | |
2094 | } | |
2095 | Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan"); | |
2096 | } | |
2097 | ||
2098 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */ | |
2099 | if (s->match_length >= MIN_MATCH) { | |
2100 | check_match(s, s->strstart, s->strstart - 1, s->match_length); | |
2101 | ||
2102 | _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); | |
2103 | ||
2104 | s->lookahead -= s->match_length; | |
2105 | s->strstart += s->match_length; | |
2106 | s->match_length = 0; | |
2107 | } else { | |
2108 | /* No match, output a literal byte */ | |
2109 | Tracevv((stderr,"%c", s->window[s->strstart])); | |
2110 | _tr_tally_lit (s, s->window[s->strstart], bflush); | |
2111 | s->lookahead--; | |
2112 | s->strstart++; | |
2113 | } | |
2114 | if (bflush) FLUSH_BLOCK(s, 0); | |
2115 | } | |
2116 | s->insert = 0; | |
2117 | if (flush == Z_FINISH) { | |
2118 | FLUSH_BLOCK(s, 1); | |
2119 | return finish_done; | |
2120 | } | |
2121 | if (s->last_lit) | |
2122 | FLUSH_BLOCK(s, 0); | |
2123 | return block_done; | |
2124 | } | |
2125 | ||
2126 | /* =========================================================================== | |
2127 | * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. | |
2128 | * (It will be regenerated if this run of deflate switches away from Huffman.) | |
2129 | */ | |
2130 | local block_state deflate_huff(s, flush) | |
2131 | deflate_state *s; | |
2132 | int flush; | |
2133 | { | |
2134 | int bflush; /* set if current block must be flushed */ | |
2135 | ||
2136 | for (;;) { | |
2137 | /* Make sure that we have a literal to write. */ | |
2138 | if (s->lookahead == 0) { | |
2139 | fill_window(s); | |
2140 | if (s->lookahead == 0) { | |
2141 | if (flush == Z_NO_FLUSH) | |
2142 | return need_more; | |
2143 | break; /* flush the current block */ | |
2144 | } | |
2145 | } | |
2146 | ||
2147 | /* Output a literal byte */ | |
2148 | s->match_length = 0; | |
2149 | Tracevv((stderr,"%c", s->window[s->strstart])); | |
2150 | _tr_tally_lit (s, s->window[s->strstart], bflush); | |
2151 | s->lookahead--; | |
2152 | s->strstart++; | |
2153 | if (bflush) FLUSH_BLOCK(s, 0); | |
2154 | } | |
2155 | s->insert = 0; | |
2156 | if (flush == Z_FINISH) { | |
2157 | FLUSH_BLOCK(s, 1); | |
2158 | return finish_done; | |
2159 | } | |
2160 | if (s->last_lit) | |
2161 | FLUSH_BLOCK(s, 0); | |
2162 | return block_done; | |
2163 | } |