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1 | /* deflate.c -- compress data using the deflation algorithm |
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2 | * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler |
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3 | * For conditions of distribution and use, see copyright notice in zlib.h |
4 | */ |
5 | |
6 | /* |
7 | * ALGORITHM |
8 | * |
9 | * The "deflation" process depends on being able to identify portions |
10 | * of the input text which are identical to earlier input (within a |
11 | * sliding window trailing behind the input currently being processed). |
12 | * |
13 | * The most straightforward technique turns out to be the fastest for |
14 | * most input files: try all possible matches and select the longest. |
15 | * The key feature of this algorithm is that insertions into the string |
16 | * dictionary are very simple and thus fast, and deletions are avoided |
17 | * completely. Insertions are performed at each input character, whereas |
18 | * string matches are performed only when the previous match ends. So it |
19 | * is preferable to spend more time in matches to allow very fast string |
20 | * insertions and avoid deletions. The matching algorithm for small |
21 | * strings is inspired from that of Rabin & Karp. A brute force approach |
22 | * is used to find longer strings when a small match has been found. |
23 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze |
24 | * (by Leonid Broukhis). |
25 | * A previous version of this file used a more sophisticated algorithm |
26 | * (by Fiala and Greene) which is guaranteed to run in linear amortized |
27 | * time, but has a larger average cost, uses more memory and is patented. |
28 | * However the F&G algorithm may be faster for some highly redundant |
29 | * files if the parameter max_chain_length (described below) is too large. |
30 | * |
31 | * ACKNOWLEDGEMENTS |
32 | * |
33 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and |
34 | * I found it in 'freeze' written by Leonid Broukhis. |
35 | * Thanks to many people for bug reports and testing. |
36 | * |
37 | * REFERENCES |
38 | * |
39 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". |
40 | * Available in http://tools.ietf.org/html/rfc1951 |
41 | * |
42 | * A description of the Rabin and Karp algorithm is given in the book |
43 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. |
44 | * |
45 | * Fiala,E.R., and Greene,D.H. |
46 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 |
47 | * |
48 | */ |
49 | |
50 | /* @(#) $Id$ */ |
51 | |
52 | #include "deflate.h" |
53 | |
54 | const char deflate_copyright[] = |
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55 | " deflate 1.2.13 Copyright 1995-2022 Jean-loup Gailly and Mark Adler "; |
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56 | /* |
57 | If you use the zlib library in a product, an acknowledgment is welcome |
58 | in the documentation of your product. If for some reason you cannot |
59 | include such an acknowledgment, I would appreciate that you keep this |
60 | copyright string in the executable of your product. |
61 | */ |
62 | |
63 | /* =========================================================================== |
64 | * Function prototypes. |
65 | */ |
66 | typedef enum { |
67 | need_more, /* block not completed, need more input or more output */ |
68 | block_done, /* block flush performed */ |
69 | finish_started, /* finish started, need only more output at next deflate */ |
70 | finish_done /* finish done, accept no more input or output */ |
71 | } block_state; |
72 | |
73 | typedef block_state (*compress_func) OF((deflate_state *s, int flush)); |
74 | /* Compression function. Returns the block state after the call. */ |
75 | |
76 | local int deflateStateCheck OF((z_streamp strm)); |
77 | local void slide_hash OF((deflate_state *s)); |
78 | local void fill_window OF((deflate_state *s)); |
79 | local block_state deflate_stored OF((deflate_state *s, int flush)); |
80 | local block_state deflate_fast OF((deflate_state *s, int flush)); |
81 | #ifndef FASTEST |
82 | local block_state deflate_slow OF((deflate_state *s, int flush)); |
83 | #endif |
84 | local block_state deflate_rle OF((deflate_state *s, int flush)); |
85 | local block_state deflate_huff OF((deflate_state *s, int flush)); |
86 | local void lm_init OF((deflate_state *s)); |
87 | local void putShortMSB OF((deflate_state *s, uInt b)); |
88 | local void flush_pending OF((z_streamp strm)); |
89 | local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); |
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90 | local uInt longest_match OF((deflate_state *s, IPos cur_match)); |
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91 | |
92 | #ifdef ZLIB_DEBUG |
93 | local void check_match OF((deflate_state *s, IPos start, IPos match, |
94 | int length)); |
95 | #endif |
96 | |
97 | /* =========================================================================== |
98 | * Local data |
99 | */ |
100 | |
101 | #define NIL 0 |
102 | /* Tail of hash chains */ |
103 | |
104 | #ifndef TOO_FAR |
105 | # define TOO_FAR 4096 |
106 | #endif |
107 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ |
108 | |
109 | /* Values for max_lazy_match, good_match and max_chain_length, depending on |
110 | * the desired pack level (0..9). The values given below have been tuned to |
111 | * exclude worst case performance for pathological files. Better values may be |
112 | * found for specific files. |
113 | */ |
114 | typedef struct config_s { |
115 | ush good_length; /* reduce lazy search above this match length */ |
116 | ush max_lazy; /* do not perform lazy search above this match length */ |
117 | ush nice_length; /* quit search above this match length */ |
118 | ush max_chain; |
119 | compress_func func; |
120 | } config; |
121 | |
122 | #ifdef FASTEST |
123 | local const config configuration_table[2] = { |
124 | /* good lazy nice chain */ |
125 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ |
126 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ |
127 | #else |
128 | local const config configuration_table[10] = { |
129 | /* good lazy nice chain */ |
130 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ |
131 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ |
132 | /* 2 */ {4, 5, 16, 8, deflate_fast}, |
133 | /* 3 */ {4, 6, 32, 32, deflate_fast}, |
134 | |
135 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ |
136 | /* 5 */ {8, 16, 32, 32, deflate_slow}, |
137 | /* 6 */ {8, 16, 128, 128, deflate_slow}, |
138 | /* 7 */ {8, 32, 128, 256, deflate_slow}, |
139 | /* 8 */ {32, 128, 258, 1024, deflate_slow}, |
140 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ |
141 | #endif |
142 | |
143 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 |
144 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different |
145 | * meaning. |
146 | */ |
147 | |
148 | /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */ |
149 | #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0)) |
150 | |
151 | /* =========================================================================== |
152 | * Update a hash value with the given input byte |
153 | * IN assertion: all calls to UPDATE_HASH are made with consecutive input |
154 | * characters, so that a running hash key can be computed from the previous |
155 | * key instead of complete recalculation each time. |
156 | */ |
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157 | #define UPDATE_HASH(s,h,c) (h = (((h) << s->hash_shift) ^ (c)) & s->hash_mask) |
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158 | |
159 | |
160 | /* =========================================================================== |
161 | * Insert string str in the dictionary and set match_head to the previous head |
162 | * of the hash chain (the most recent string with same hash key). Return |
163 | * the previous length of the hash chain. |
164 | * If this file is compiled with -DFASTEST, the compression level is forced |
165 | * to 1, and no hash chains are maintained. |
166 | * IN assertion: all calls to INSERT_STRING are made with consecutive input |
167 | * characters and the first MIN_MATCH bytes of str are valid (except for |
168 | * the last MIN_MATCH-1 bytes of the input file). |
169 | */ |
170 | #ifdef FASTEST |
171 | #define INSERT_STRING(s, str, match_head) \ |
172 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ |
173 | match_head = s->head[s->ins_h], \ |
174 | s->head[s->ins_h] = (Pos)(str)) |
175 | #else |
176 | #define INSERT_STRING(s, str, match_head) \ |
177 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ |
178 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ |
179 | s->head[s->ins_h] = (Pos)(str)) |
180 | #endif |
181 | |
182 | /* =========================================================================== |
183 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems). |
184 | * prev[] will be initialized on the fly. |
185 | */ |
186 | #define CLEAR_HASH(s) \ |
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187 | do { \ |
188 | s->head[s->hash_size - 1] = NIL; \ |
189 | zmemzero((Bytef *)s->head, \ |
190 | (unsigned)(s->hash_size - 1)*sizeof(*s->head)); \ |
191 | } while (0) |
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192 | |
193 | /* =========================================================================== |
194 | * Slide the hash table when sliding the window down (could be avoided with 32 |
195 | * bit values at the expense of memory usage). We slide even when level == 0 to |
196 | * keep the hash table consistent if we switch back to level > 0 later. |
197 | */ |
198 | local void slide_hash(s) |
199 | deflate_state *s; |
200 | { |
201 | unsigned n, m; |
202 | Posf *p; |
203 | uInt wsize = s->w_size; |
204 | |
205 | n = s->hash_size; |
206 | p = &s->head[n]; |
207 | do { |
208 | m = *--p; |
209 | *p = (Pos)(m >= wsize ? m - wsize : NIL); |
210 | } while (--n); |
211 | n = wsize; |
212 | #ifndef FASTEST |
213 | p = &s->prev[n]; |
214 | do { |
215 | m = *--p; |
216 | *p = (Pos)(m >= wsize ? m - wsize : NIL); |
217 | /* If n is not on any hash chain, prev[n] is garbage but |
218 | * its value will never be used. |
219 | */ |
220 | } while (--n); |
221 | #endif |
222 | } |
223 | |
224 | /* ========================================================================= */ |
225 | int ZEXPORT deflateInit_(strm, level, version, stream_size) |
226 | z_streamp strm; |
227 | int level; |
228 | const char *version; |
229 | int stream_size; |
230 | { |
231 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, |
232 | Z_DEFAULT_STRATEGY, version, stream_size); |
233 | /* To do: ignore strm->next_in if we use it as window */ |
234 | } |
235 | |
236 | /* ========================================================================= */ |
237 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, |
238 | version, stream_size) |
239 | z_streamp strm; |
240 | int level; |
241 | int method; |
242 | int windowBits; |
243 | int memLevel; |
244 | int strategy; |
245 | const char *version; |
246 | int stream_size; |
247 | { |
248 | deflate_state *s; |
249 | int wrap = 1; |
250 | static const char my_version[] = ZLIB_VERSION; |
251 | |
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252 | if (version == Z_NULL || version[0] != my_version[0] || |
253 | stream_size != sizeof(z_stream)) { |
254 | return Z_VERSION_ERROR; |
255 | } |
256 | if (strm == Z_NULL) return Z_STREAM_ERROR; |
257 | |
258 | strm->msg = Z_NULL; |
259 | if (strm->zalloc == (alloc_func)0) { |
260 | #ifdef Z_SOLO |
261 | return Z_STREAM_ERROR; |
262 | #else |
263 | strm->zalloc = zcalloc; |
264 | strm->opaque = (voidpf)0; |
265 | #endif |
266 | } |
267 | if (strm->zfree == (free_func)0) |
268 | #ifdef Z_SOLO |
269 | return Z_STREAM_ERROR; |
270 | #else |
271 | strm->zfree = zcfree; |
272 | #endif |
273 | |
274 | #ifdef FASTEST |
275 | if (level != 0) level = 1; |
276 | #else |
277 | if (level == Z_DEFAULT_COMPRESSION) level = 6; |
278 | #endif |
279 | |
280 | if (windowBits < 0) { /* suppress zlib wrapper */ |
281 | wrap = 0; |
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282 | if (windowBits < -15) |
283 | return Z_STREAM_ERROR; |
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284 | windowBits = -windowBits; |
285 | } |
286 | #ifdef GZIP |
287 | else if (windowBits > 15) { |
288 | wrap = 2; /* write gzip wrapper instead */ |
289 | windowBits -= 16; |
290 | } |
291 | #endif |
292 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || |
293 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || |
294 | strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) { |
295 | return Z_STREAM_ERROR; |
296 | } |
297 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ |
298 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); |
299 | if (s == Z_NULL) return Z_MEM_ERROR; |
300 | strm->state = (struct internal_state FAR *)s; |
301 | s->strm = strm; |
302 | s->status = INIT_STATE; /* to pass state test in deflateReset() */ |
303 | |
304 | s->wrap = wrap; |
305 | s->gzhead = Z_NULL; |
306 | s->w_bits = (uInt)windowBits; |
307 | s->w_size = 1 << s->w_bits; |
308 | s->w_mask = s->w_size - 1; |
309 | |
310 | s->hash_bits = (uInt)memLevel + 7; |
311 | s->hash_size = 1 << s->hash_bits; |
312 | s->hash_mask = s->hash_size - 1; |
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313 | s->hash_shift = ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH); |
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314 | |
315 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); |
316 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); |
317 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); |
318 | |
319 | s->high_water = 0; /* nothing written to s->window yet */ |
320 | |
321 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ |
322 | |
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323 | /* We overlay pending_buf and sym_buf. This works since the average size |
324 | * for length/distance pairs over any compressed block is assured to be 31 |
325 | * bits or less. |
326 | * |
327 | * Analysis: The longest fixed codes are a length code of 8 bits plus 5 |
328 | * extra bits, for lengths 131 to 257. The longest fixed distance codes are |
329 | * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest |
330 | * possible fixed-codes length/distance pair is then 31 bits total. |
331 | * |
332 | * sym_buf starts one-fourth of the way into pending_buf. So there are |
333 | * three bytes in sym_buf for every four bytes in pending_buf. Each symbol |
334 | * in sym_buf is three bytes -- two for the distance and one for the |
335 | * literal/length. As each symbol is consumed, the pointer to the next |
336 | * sym_buf value to read moves forward three bytes. From that symbol, up to |
337 | * 31 bits are written to pending_buf. The closest the written pending_buf |
338 | * bits gets to the next sym_buf symbol to read is just before the last |
339 | * code is written. At that time, 31*(n - 2) bits have been written, just |
340 | * after 24*(n - 2) bits have been consumed from sym_buf. sym_buf starts at |
341 | * 8*n bits into pending_buf. (Note that the symbol buffer fills when n - 1 |
342 | * symbols are written.) The closest the writing gets to what is unread is |
343 | * then n + 14 bits. Here n is lit_bufsize, which is 16384 by default, and |
344 | * can range from 128 to 32768. |
345 | * |
346 | * Therefore, at a minimum, there are 142 bits of space between what is |
347 | * written and what is read in the overlain buffers, so the symbols cannot |
348 | * be overwritten by the compressed data. That space is actually 139 bits, |
349 | * due to the three-bit fixed-code block header. |
350 | * |
351 | * That covers the case where either Z_FIXED is specified, forcing fixed |
352 | * codes, or when the use of fixed codes is chosen, because that choice |
353 | * results in a smaller compressed block than dynamic codes. That latter |
354 | * condition then assures that the above analysis also covers all dynamic |
355 | * blocks. A dynamic-code block will only be chosen to be emitted if it has |
356 | * fewer bits than a fixed-code block would for the same set of symbols. |
357 | * Therefore its average symbol length is assured to be less than 31. So |
358 | * the compressed data for a dynamic block also cannot overwrite the |
359 | * symbols from which it is being constructed. |
360 | */ |
361 | |
362 | s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4); |
363 | s->pending_buf_size = (ulg)s->lit_bufsize * 4; |
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364 | |
365 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || |
366 | s->pending_buf == Z_NULL) { |
367 | s->status = FINISH_STATE; |
368 | strm->msg = ERR_MSG(Z_MEM_ERROR); |
369 | deflateEnd (strm); |
370 | return Z_MEM_ERROR; |
371 | } |
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372 | s->sym_buf = s->pending_buf + s->lit_bufsize; |
373 | s->sym_end = (s->lit_bufsize - 1) * 3; |
374 | /* We avoid equality with lit_bufsize*3 because of wraparound at 64K |
375 | * on 16 bit machines and because stored blocks are restricted to |
376 | * 64K-1 bytes. |
377 | */ |
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378 | |
379 | s->level = level; |
380 | s->strategy = strategy; |
381 | s->method = (Byte)method; |
382 | |
383 | return deflateReset(strm); |
384 | } |
385 | |
386 | /* ========================================================================= |
387 | * Check for a valid deflate stream state. Return 0 if ok, 1 if not. |
388 | */ |
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389 | local int deflateStateCheck(strm) |
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390 | z_streamp strm; |
391 | { |
392 | deflate_state *s; |
393 | if (strm == Z_NULL || |
394 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) |
395 | return 1; |
396 | s = strm->state; |
397 | if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE && |
398 | #ifdef GZIP |
399 | s->status != GZIP_STATE && |
400 | #endif |
401 | s->status != EXTRA_STATE && |
402 | s->status != NAME_STATE && |
403 | s->status != COMMENT_STATE && |
404 | s->status != HCRC_STATE && |
405 | s->status != BUSY_STATE && |
406 | s->status != FINISH_STATE)) |
407 | return 1; |
408 | return 0; |
409 | } |
410 | |
411 | /* ========================================================================= */ |
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412 | int ZEXPORT deflateSetDictionary(strm, dictionary, dictLength) |
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413 | z_streamp strm; |
414 | const Bytef *dictionary; |
415 | uInt dictLength; |
416 | { |
417 | deflate_state *s; |
418 | uInt str, n; |
419 | int wrap; |
420 | unsigned avail; |
421 | z_const unsigned char *next; |
422 | |
423 | if (deflateStateCheck(strm) || dictionary == Z_NULL) |
424 | return Z_STREAM_ERROR; |
425 | s = strm->state; |
426 | wrap = s->wrap; |
427 | if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) |
428 | return Z_STREAM_ERROR; |
429 | |
430 | /* when using zlib wrappers, compute Adler-32 for provided dictionary */ |
431 | if (wrap == 1) |
432 | strm->adler = adler32(strm->adler, dictionary, dictLength); |
433 | s->wrap = 0; /* avoid computing Adler-32 in read_buf */ |
434 | |
435 | /* if dictionary would fill window, just replace the history */ |
436 | if (dictLength >= s->w_size) { |
437 | if (wrap == 0) { /* already empty otherwise */ |
438 | CLEAR_HASH(s); |
439 | s->strstart = 0; |
440 | s->block_start = 0L; |
441 | s->insert = 0; |
442 | } |
443 | dictionary += dictLength - s->w_size; /* use the tail */ |
444 | dictLength = s->w_size; |
445 | } |
446 | |
447 | /* insert dictionary into window and hash */ |
448 | avail = strm->avail_in; |
449 | next = strm->next_in; |
450 | strm->avail_in = dictLength; |
451 | strm->next_in = (z_const Bytef *)dictionary; |
452 | fill_window(s); |
453 | while (s->lookahead >= MIN_MATCH) { |
454 | str = s->strstart; |
455 | n = s->lookahead - (MIN_MATCH-1); |
456 | do { |
457 | UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); |
458 | #ifndef FASTEST |
459 | s->prev[str & s->w_mask] = s->head[s->ins_h]; |
460 | #endif |
461 | s->head[s->ins_h] = (Pos)str; |
462 | str++; |
463 | } while (--n); |
464 | s->strstart = str; |
465 | s->lookahead = MIN_MATCH-1; |
466 | fill_window(s); |
467 | } |
468 | s->strstart += s->lookahead; |
469 | s->block_start = (long)s->strstart; |
470 | s->insert = s->lookahead; |
471 | s->lookahead = 0; |
472 | s->match_length = s->prev_length = MIN_MATCH-1; |
473 | s->match_available = 0; |
474 | strm->next_in = next; |
475 | strm->avail_in = avail; |
476 | s->wrap = wrap; |
477 | return Z_OK; |
478 | } |
479 | |
480 | /* ========================================================================= */ |
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481 | int ZEXPORT deflateGetDictionary(strm, dictionary, dictLength) |
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482 | z_streamp strm; |
483 | Bytef *dictionary; |
484 | uInt *dictLength; |
485 | { |
486 | deflate_state *s; |
487 | uInt len; |
488 | |
489 | if (deflateStateCheck(strm)) |
490 | return Z_STREAM_ERROR; |
491 | s = strm->state; |
492 | len = s->strstart + s->lookahead; |
493 | if (len > s->w_size) |
494 | len = s->w_size; |
495 | if (dictionary != Z_NULL && len) |
496 | zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len); |
497 | if (dictLength != Z_NULL) |
498 | *dictLength = len; |
499 | return Z_OK; |
500 | } |
501 | |
502 | /* ========================================================================= */ |
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503 | int ZEXPORT deflateResetKeep(strm) |
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504 | z_streamp strm; |
505 | { |
506 | deflate_state *s; |
507 | |
508 | if (deflateStateCheck(strm)) { |
509 | return Z_STREAM_ERROR; |
510 | } |
511 | |
512 | strm->total_in = strm->total_out = 0; |
513 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ |
514 | strm->data_type = Z_UNKNOWN; |
515 | |
516 | s = (deflate_state *)strm->state; |
517 | s->pending = 0; |
518 | s->pending_out = s->pending_buf; |
519 | |
520 | if (s->wrap < 0) { |
521 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ |
522 | } |
523 | s->status = |
524 | #ifdef GZIP |
525 | s->wrap == 2 ? GZIP_STATE : |
526 | #endif |
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527 | INIT_STATE; |
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528 | strm->adler = |
529 | #ifdef GZIP |
530 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) : |
531 | #endif |
532 | adler32(0L, Z_NULL, 0); |
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533 | s->last_flush = -2; |
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534 | |
535 | _tr_init(s); |
536 | |
537 | return Z_OK; |
538 | } |
539 | |
540 | /* ========================================================================= */ |
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541 | int ZEXPORT deflateReset(strm) |
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542 | z_streamp strm; |
543 | { |
544 | int ret; |
545 | |
546 | ret = deflateResetKeep(strm); |
547 | if (ret == Z_OK) |
548 | lm_init(strm->state); |
549 | return ret; |
550 | } |
551 | |
552 | /* ========================================================================= */ |
9e052883 |
553 | int ZEXPORT deflateSetHeader(strm, head) |
b24e7fce |
554 | z_streamp strm; |
555 | gz_headerp head; |
556 | { |
557 | if (deflateStateCheck(strm) || strm->state->wrap != 2) |
558 | return Z_STREAM_ERROR; |
559 | strm->state->gzhead = head; |
560 | return Z_OK; |
561 | } |
562 | |
563 | /* ========================================================================= */ |
9e052883 |
564 | int ZEXPORT deflatePending(strm, pending, bits) |
b24e7fce |
565 | unsigned *pending; |
566 | int *bits; |
567 | z_streamp strm; |
568 | { |
569 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
570 | if (pending != Z_NULL) |
571 | *pending = strm->state->pending; |
572 | if (bits != Z_NULL) |
573 | *bits = strm->state->bi_valid; |
574 | return Z_OK; |
575 | } |
576 | |
577 | /* ========================================================================= */ |
9e052883 |
578 | int ZEXPORT deflatePrime(strm, bits, value) |
b24e7fce |
579 | z_streamp strm; |
580 | int bits; |
581 | int value; |
582 | { |
583 | deflate_state *s; |
584 | int put; |
585 | |
586 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
587 | s = strm->state; |
9e052883 |
588 | if (bits < 0 || bits > 16 || |
589 | s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3)) |
b24e7fce |
590 | return Z_BUF_ERROR; |
591 | do { |
592 | put = Buf_size - s->bi_valid; |
593 | if (put > bits) |
594 | put = bits; |
595 | s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); |
596 | s->bi_valid += put; |
597 | _tr_flush_bits(s); |
598 | value >>= put; |
599 | bits -= put; |
600 | } while (bits); |
601 | return Z_OK; |
602 | } |
603 | |
604 | /* ========================================================================= */ |
605 | int ZEXPORT deflateParams(strm, level, strategy) |
606 | z_streamp strm; |
607 | int level; |
608 | int strategy; |
609 | { |
610 | deflate_state *s; |
611 | compress_func func; |
612 | |
613 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
614 | s = strm->state; |
615 | |
616 | #ifdef FASTEST |
617 | if (level != 0) level = 1; |
618 | #else |
619 | if (level == Z_DEFAULT_COMPRESSION) level = 6; |
620 | #endif |
621 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { |
622 | return Z_STREAM_ERROR; |
623 | } |
624 | func = configuration_table[s->level].func; |
625 | |
626 | if ((strategy != s->strategy || func != configuration_table[level].func) && |
9e052883 |
627 | s->last_flush != -2) { |
b24e7fce |
628 | /* Flush the last buffer: */ |
629 | int err = deflate(strm, Z_BLOCK); |
630 | if (err == Z_STREAM_ERROR) |
631 | return err; |
9e052883 |
632 | if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead) |
b24e7fce |
633 | return Z_BUF_ERROR; |
634 | } |
635 | if (s->level != level) { |
636 | if (s->level == 0 && s->matches != 0) { |
637 | if (s->matches == 1) |
638 | slide_hash(s); |
639 | else |
640 | CLEAR_HASH(s); |
641 | s->matches = 0; |
642 | } |
643 | s->level = level; |
644 | s->max_lazy_match = configuration_table[level].max_lazy; |
645 | s->good_match = configuration_table[level].good_length; |
646 | s->nice_match = configuration_table[level].nice_length; |
647 | s->max_chain_length = configuration_table[level].max_chain; |
648 | } |
649 | s->strategy = strategy; |
650 | return Z_OK; |
651 | } |
652 | |
653 | /* ========================================================================= */ |
654 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) |
655 | z_streamp strm; |
656 | int good_length; |
657 | int max_lazy; |
658 | int nice_length; |
659 | int max_chain; |
660 | { |
661 | deflate_state *s; |
662 | |
663 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
664 | s = strm->state; |
665 | s->good_match = (uInt)good_length; |
666 | s->max_lazy_match = (uInt)max_lazy; |
667 | s->nice_match = nice_length; |
668 | s->max_chain_length = (uInt)max_chain; |
669 | return Z_OK; |
670 | } |
671 | |
672 | /* ========================================================================= |
9e052883 |
673 | * For the default windowBits of 15 and memLevel of 8, this function returns a |
674 | * close to exact, as well as small, upper bound on the compressed size. This |
675 | * is an expansion of ~0.03%, plus a small constant. |
676 | * |
677 | * For any setting other than those defaults for windowBits and memLevel, one |
678 | * of two worst case bounds is returned. This is at most an expansion of ~4% or |
679 | * ~13%, plus a small constant. |
b24e7fce |
680 | * |
9e052883 |
681 | * Both the 0.03% and 4% derive from the overhead of stored blocks. The first |
682 | * one is for stored blocks of 16383 bytes (memLevel == 8), whereas the second |
683 | * is for stored blocks of 127 bytes (the worst case memLevel == 1). The |
684 | * expansion results from five bytes of header for each stored block. |
b24e7fce |
685 | * |
9e052883 |
686 | * The larger expansion of 13% results from a window size less than or equal to |
687 | * the symbols buffer size (windowBits <= memLevel + 7). In that case some of |
688 | * the data being compressed may have slid out of the sliding window, impeding |
689 | * a stored block from being emitted. Then the only choice is a fixed or |
690 | * dynamic block, where a fixed block limits the maximum expansion to 9 bits |
691 | * per 8-bit byte, plus 10 bits for every block. The smallest block size for |
692 | * which this can occur is 255 (memLevel == 2). |
693 | * |
694 | * Shifts are used to approximate divisions, for speed. |
b24e7fce |
695 | */ |
696 | uLong ZEXPORT deflateBound(strm, sourceLen) |
697 | z_streamp strm; |
698 | uLong sourceLen; |
699 | { |
700 | deflate_state *s; |
9e052883 |
701 | uLong fixedlen, storelen, wraplen; |
702 | |
703 | /* upper bound for fixed blocks with 9-bit literals and length 255 |
704 | (memLevel == 2, which is the lowest that may not use stored blocks) -- |
705 | ~13% overhead plus a small constant */ |
706 | fixedlen = sourceLen + (sourceLen >> 3) + (sourceLen >> 8) + |
707 | (sourceLen >> 9) + 4; |
b24e7fce |
708 | |
9e052883 |
709 | /* upper bound for stored blocks with length 127 (memLevel == 1) -- |
710 | ~4% overhead plus a small constant */ |
711 | storelen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) + |
712 | (sourceLen >> 11) + 7; |
b24e7fce |
713 | |
9e052883 |
714 | /* if can't get parameters, return larger bound plus a zlib wrapper */ |
b24e7fce |
715 | if (deflateStateCheck(strm)) |
9e052883 |
716 | return (fixedlen > storelen ? fixedlen : storelen) + 6; |
b24e7fce |
717 | |
718 | /* compute wrapper length */ |
719 | s = strm->state; |
720 | switch (s->wrap) { |
721 | case 0: /* raw deflate */ |
722 | wraplen = 0; |
723 | break; |
724 | case 1: /* zlib wrapper */ |
725 | wraplen = 6 + (s->strstart ? 4 : 0); |
726 | break; |
727 | #ifdef GZIP |
728 | case 2: /* gzip wrapper */ |
729 | wraplen = 18; |
730 | if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ |
731 | Bytef *str; |
732 | if (s->gzhead->extra != Z_NULL) |
733 | wraplen += 2 + s->gzhead->extra_len; |
734 | str = s->gzhead->name; |
735 | if (str != Z_NULL) |
736 | do { |
737 | wraplen++; |
738 | } while (*str++); |
739 | str = s->gzhead->comment; |
740 | if (str != Z_NULL) |
741 | do { |
742 | wraplen++; |
743 | } while (*str++); |
744 | if (s->gzhead->hcrc) |
745 | wraplen += 2; |
746 | } |
747 | break; |
748 | #endif |
749 | default: /* for compiler happiness */ |
750 | wraplen = 6; |
751 | } |
752 | |
9e052883 |
753 | /* if not default parameters, return one of the conservative bounds */ |
b24e7fce |
754 | if (s->w_bits != 15 || s->hash_bits != 8 + 7) |
9e052883 |
755 | return (s->w_bits <= s->hash_bits ? fixedlen : storelen) + wraplen; |
b24e7fce |
756 | |
9e052883 |
757 | /* default settings: return tight bound for that case -- ~0.03% overhead |
758 | plus a small constant */ |
b24e7fce |
759 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + |
760 | (sourceLen >> 25) + 13 - 6 + wraplen; |
761 | } |
762 | |
763 | /* ========================================================================= |
764 | * Put a short in the pending buffer. The 16-bit value is put in MSB order. |
765 | * IN assertion: the stream state is correct and there is enough room in |
766 | * pending_buf. |
767 | */ |
9e052883 |
768 | local void putShortMSB(s, b) |
b24e7fce |
769 | deflate_state *s; |
770 | uInt b; |
771 | { |
772 | put_byte(s, (Byte)(b >> 8)); |
773 | put_byte(s, (Byte)(b & 0xff)); |
774 | } |
775 | |
776 | /* ========================================================================= |
777 | * Flush as much pending output as possible. All deflate() output, except for |
778 | * some deflate_stored() output, goes through this function so some |
779 | * applications may wish to modify it to avoid allocating a large |
780 | * strm->next_out buffer and copying into it. (See also read_buf()). |
781 | */ |
782 | local void flush_pending(strm) |
783 | z_streamp strm; |
784 | { |
785 | unsigned len; |
786 | deflate_state *s = strm->state; |
787 | |
788 | _tr_flush_bits(s); |
789 | len = s->pending; |
790 | if (len > strm->avail_out) len = strm->avail_out; |
791 | if (len == 0) return; |
792 | |
793 | zmemcpy(strm->next_out, s->pending_out, len); |
794 | strm->next_out += len; |
795 | s->pending_out += len; |
796 | strm->total_out += len; |
797 | strm->avail_out -= len; |
798 | s->pending -= len; |
799 | if (s->pending == 0) { |
800 | s->pending_out = s->pending_buf; |
801 | } |
802 | } |
803 | |
804 | /* =========================================================================== |
805 | * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1]. |
806 | */ |
807 | #define HCRC_UPDATE(beg) \ |
808 | do { \ |
809 | if (s->gzhead->hcrc && s->pending > (beg)) \ |
810 | strm->adler = crc32(strm->adler, s->pending_buf + (beg), \ |
811 | s->pending - (beg)); \ |
812 | } while (0) |
813 | |
814 | /* ========================================================================= */ |
9e052883 |
815 | int ZEXPORT deflate(strm, flush) |
b24e7fce |
816 | z_streamp strm; |
817 | int flush; |
818 | { |
819 | int old_flush; /* value of flush param for previous deflate call */ |
820 | deflate_state *s; |
821 | |
822 | if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { |
823 | return Z_STREAM_ERROR; |
824 | } |
825 | s = strm->state; |
826 | |
827 | if (strm->next_out == Z_NULL || |
828 | (strm->avail_in != 0 && strm->next_in == Z_NULL) || |
829 | (s->status == FINISH_STATE && flush != Z_FINISH)) { |
830 | ERR_RETURN(strm, Z_STREAM_ERROR); |
831 | } |
832 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); |
833 | |
834 | old_flush = s->last_flush; |
835 | s->last_flush = flush; |
836 | |
837 | /* Flush as much pending output as possible */ |
838 | if (s->pending != 0) { |
839 | flush_pending(strm); |
840 | if (strm->avail_out == 0) { |
841 | /* Since avail_out is 0, deflate will be called again with |
842 | * more output space, but possibly with both pending and |
843 | * avail_in equal to zero. There won't be anything to do, |
844 | * but this is not an error situation so make sure we |
845 | * return OK instead of BUF_ERROR at next call of deflate: |
846 | */ |
847 | s->last_flush = -1; |
848 | return Z_OK; |
849 | } |
850 | |
851 | /* Make sure there is something to do and avoid duplicate consecutive |
852 | * flushes. For repeated and useless calls with Z_FINISH, we keep |
853 | * returning Z_STREAM_END instead of Z_BUF_ERROR. |
854 | */ |
855 | } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && |
856 | flush != Z_FINISH) { |
857 | ERR_RETURN(strm, Z_BUF_ERROR); |
858 | } |
859 | |
860 | /* User must not provide more input after the first FINISH: */ |
861 | if (s->status == FINISH_STATE && strm->avail_in != 0) { |
862 | ERR_RETURN(strm, Z_BUF_ERROR); |
863 | } |
864 | |
865 | /* Write the header */ |
9e052883 |
866 | if (s->status == INIT_STATE && s->wrap == 0) |
867 | s->status = BUSY_STATE; |
b24e7fce |
868 | if (s->status == INIT_STATE) { |
869 | /* zlib header */ |
9e052883 |
870 | uInt header = (Z_DEFLATED + ((s->w_bits - 8) << 4)) << 8; |
b24e7fce |
871 | uInt level_flags; |
872 | |
873 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) |
874 | level_flags = 0; |
875 | else if (s->level < 6) |
876 | level_flags = 1; |
877 | else if (s->level == 6) |
878 | level_flags = 2; |
879 | else |
880 | level_flags = 3; |
881 | header |= (level_flags << 6); |
882 | if (s->strstart != 0) header |= PRESET_DICT; |
883 | header += 31 - (header % 31); |
884 | |
885 | putShortMSB(s, header); |
886 | |
887 | /* Save the adler32 of the preset dictionary: */ |
888 | if (s->strstart != 0) { |
889 | putShortMSB(s, (uInt)(strm->adler >> 16)); |
890 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); |
891 | } |
892 | strm->adler = adler32(0L, Z_NULL, 0); |
893 | s->status = BUSY_STATE; |
894 | |
895 | /* Compression must start with an empty pending buffer */ |
896 | flush_pending(strm); |
897 | if (s->pending != 0) { |
898 | s->last_flush = -1; |
899 | return Z_OK; |
900 | } |
901 | } |
902 | #ifdef GZIP |
903 | if (s->status == GZIP_STATE) { |
904 | /* gzip header */ |
905 | strm->adler = crc32(0L, Z_NULL, 0); |
906 | put_byte(s, 31); |
907 | put_byte(s, 139); |
908 | put_byte(s, 8); |
909 | if (s->gzhead == Z_NULL) { |
910 | put_byte(s, 0); |
911 | put_byte(s, 0); |
912 | put_byte(s, 0); |
913 | put_byte(s, 0); |
914 | put_byte(s, 0); |
915 | put_byte(s, s->level == 9 ? 2 : |
916 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? |
917 | 4 : 0)); |
918 | put_byte(s, OS_CODE); |
919 | s->status = BUSY_STATE; |
920 | |
921 | /* Compression must start with an empty pending buffer */ |
922 | flush_pending(strm); |
923 | if (s->pending != 0) { |
924 | s->last_flush = -1; |
925 | return Z_OK; |
926 | } |
927 | } |
928 | else { |
929 | put_byte(s, (s->gzhead->text ? 1 : 0) + |
930 | (s->gzhead->hcrc ? 2 : 0) + |
931 | (s->gzhead->extra == Z_NULL ? 0 : 4) + |
932 | (s->gzhead->name == Z_NULL ? 0 : 8) + |
933 | (s->gzhead->comment == Z_NULL ? 0 : 16) |
934 | ); |
935 | put_byte(s, (Byte)(s->gzhead->time & 0xff)); |
936 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); |
937 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); |
938 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); |
939 | put_byte(s, s->level == 9 ? 2 : |
940 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? |
941 | 4 : 0)); |
942 | put_byte(s, s->gzhead->os & 0xff); |
943 | if (s->gzhead->extra != Z_NULL) { |
944 | put_byte(s, s->gzhead->extra_len & 0xff); |
945 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); |
946 | } |
947 | if (s->gzhead->hcrc) |
948 | strm->adler = crc32(strm->adler, s->pending_buf, |
949 | s->pending); |
950 | s->gzindex = 0; |
951 | s->status = EXTRA_STATE; |
952 | } |
953 | } |
954 | if (s->status == EXTRA_STATE) { |
955 | if (s->gzhead->extra != Z_NULL) { |
956 | ulg beg = s->pending; /* start of bytes to update crc */ |
957 | uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex; |
958 | while (s->pending + left > s->pending_buf_size) { |
959 | uInt copy = s->pending_buf_size - s->pending; |
960 | zmemcpy(s->pending_buf + s->pending, |
961 | s->gzhead->extra + s->gzindex, copy); |
962 | s->pending = s->pending_buf_size; |
963 | HCRC_UPDATE(beg); |
964 | s->gzindex += copy; |
965 | flush_pending(strm); |
966 | if (s->pending != 0) { |
967 | s->last_flush = -1; |
968 | return Z_OK; |
969 | } |
970 | beg = 0; |
971 | left -= copy; |
972 | } |
973 | zmemcpy(s->pending_buf + s->pending, |
974 | s->gzhead->extra + s->gzindex, left); |
975 | s->pending += left; |
976 | HCRC_UPDATE(beg); |
977 | s->gzindex = 0; |
978 | } |
979 | s->status = NAME_STATE; |
980 | } |
981 | if (s->status == NAME_STATE) { |
982 | if (s->gzhead->name != Z_NULL) { |
983 | ulg beg = s->pending; /* start of bytes to update crc */ |
984 | int val; |
985 | do { |
986 | if (s->pending == s->pending_buf_size) { |
987 | HCRC_UPDATE(beg); |
988 | flush_pending(strm); |
989 | if (s->pending != 0) { |
990 | s->last_flush = -1; |
991 | return Z_OK; |
992 | } |
993 | beg = 0; |
994 | } |
995 | val = s->gzhead->name[s->gzindex++]; |
996 | put_byte(s, val); |
997 | } while (val != 0); |
998 | HCRC_UPDATE(beg); |
999 | s->gzindex = 0; |
1000 | } |
1001 | s->status = COMMENT_STATE; |
1002 | } |
1003 | if (s->status == COMMENT_STATE) { |
1004 | if (s->gzhead->comment != Z_NULL) { |
1005 | ulg beg = s->pending; /* start of bytes to update crc */ |
1006 | int val; |
1007 | do { |
1008 | if (s->pending == s->pending_buf_size) { |
1009 | HCRC_UPDATE(beg); |
1010 | flush_pending(strm); |
1011 | if (s->pending != 0) { |
1012 | s->last_flush = -1; |
1013 | return Z_OK; |
1014 | } |
1015 | beg = 0; |
1016 | } |
1017 | val = s->gzhead->comment[s->gzindex++]; |
1018 | put_byte(s, val); |
1019 | } while (val != 0); |
1020 | HCRC_UPDATE(beg); |
1021 | } |
1022 | s->status = HCRC_STATE; |
1023 | } |
1024 | if (s->status == HCRC_STATE) { |
1025 | if (s->gzhead->hcrc) { |
1026 | if (s->pending + 2 > s->pending_buf_size) { |
1027 | flush_pending(strm); |
1028 | if (s->pending != 0) { |
1029 | s->last_flush = -1; |
1030 | return Z_OK; |
1031 | } |
1032 | } |
1033 | put_byte(s, (Byte)(strm->adler & 0xff)); |
1034 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); |
1035 | strm->adler = crc32(0L, Z_NULL, 0); |
1036 | } |
1037 | s->status = BUSY_STATE; |
1038 | |
1039 | /* Compression must start with an empty pending buffer */ |
1040 | flush_pending(strm); |
1041 | if (s->pending != 0) { |
1042 | s->last_flush = -1; |
1043 | return Z_OK; |
1044 | } |
1045 | } |
1046 | #endif |
1047 | |
1048 | /* Start a new block or continue the current one. |
1049 | */ |
1050 | if (strm->avail_in != 0 || s->lookahead != 0 || |
1051 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { |
1052 | block_state bstate; |
1053 | |
1054 | bstate = s->level == 0 ? deflate_stored(s, flush) : |
1055 | s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : |
1056 | s->strategy == Z_RLE ? deflate_rle(s, flush) : |
1057 | (*(configuration_table[s->level].func))(s, flush); |
1058 | |
1059 | if (bstate == finish_started || bstate == finish_done) { |
1060 | s->status = FINISH_STATE; |
1061 | } |
1062 | if (bstate == need_more || bstate == finish_started) { |
1063 | if (strm->avail_out == 0) { |
1064 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ |
1065 | } |
1066 | return Z_OK; |
1067 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call |
1068 | * of deflate should use the same flush parameter to make sure |
1069 | * that the flush is complete. So we don't have to output an |
1070 | * empty block here, this will be done at next call. This also |
1071 | * ensures that for a very small output buffer, we emit at most |
1072 | * one empty block. |
1073 | */ |
1074 | } |
1075 | if (bstate == block_done) { |
1076 | if (flush == Z_PARTIAL_FLUSH) { |
1077 | _tr_align(s); |
1078 | } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ |
1079 | _tr_stored_block(s, (char*)0, 0L, 0); |
1080 | /* For a full flush, this empty block will be recognized |
1081 | * as a special marker by inflate_sync(). |
1082 | */ |
1083 | if (flush == Z_FULL_FLUSH) { |
1084 | CLEAR_HASH(s); /* forget history */ |
1085 | if (s->lookahead == 0) { |
1086 | s->strstart = 0; |
1087 | s->block_start = 0L; |
1088 | s->insert = 0; |
1089 | } |
1090 | } |
1091 | } |
1092 | flush_pending(strm); |
1093 | if (strm->avail_out == 0) { |
1094 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ |
1095 | return Z_OK; |
1096 | } |
1097 | } |
1098 | } |
1099 | |
1100 | if (flush != Z_FINISH) return Z_OK; |
1101 | if (s->wrap <= 0) return Z_STREAM_END; |
1102 | |
1103 | /* Write the trailer */ |
1104 | #ifdef GZIP |
1105 | if (s->wrap == 2) { |
1106 | put_byte(s, (Byte)(strm->adler & 0xff)); |
1107 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); |
1108 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); |
1109 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); |
1110 | put_byte(s, (Byte)(strm->total_in & 0xff)); |
1111 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); |
1112 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); |
1113 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); |
1114 | } |
1115 | else |
1116 | #endif |
1117 | { |
1118 | putShortMSB(s, (uInt)(strm->adler >> 16)); |
1119 | putShortMSB(s, (uInt)(strm->adler & 0xffff)); |
1120 | } |
1121 | flush_pending(strm); |
1122 | /* If avail_out is zero, the application will call deflate again |
1123 | * to flush the rest. |
1124 | */ |
1125 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ |
1126 | return s->pending != 0 ? Z_OK : Z_STREAM_END; |
1127 | } |
1128 | |
1129 | /* ========================================================================= */ |
9e052883 |
1130 | int ZEXPORT deflateEnd(strm) |
b24e7fce |
1131 | z_streamp strm; |
1132 | { |
1133 | int status; |
1134 | |
1135 | if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
1136 | |
1137 | status = strm->state->status; |
1138 | |
1139 | /* Deallocate in reverse order of allocations: */ |
1140 | TRY_FREE(strm, strm->state->pending_buf); |
1141 | TRY_FREE(strm, strm->state->head); |
1142 | TRY_FREE(strm, strm->state->prev); |
1143 | TRY_FREE(strm, strm->state->window); |
1144 | |
1145 | ZFREE(strm, strm->state); |
1146 | strm->state = Z_NULL; |
1147 | |
1148 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; |
1149 | } |
1150 | |
1151 | /* ========================================================================= |
1152 | * Copy the source state to the destination state. |
1153 | * To simplify the source, this is not supported for 16-bit MSDOS (which |
1154 | * doesn't have enough memory anyway to duplicate compression states). |
1155 | */ |
9e052883 |
1156 | int ZEXPORT deflateCopy(dest, source) |
b24e7fce |
1157 | z_streamp dest; |
1158 | z_streamp source; |
1159 | { |
1160 | #ifdef MAXSEG_64K |
1161 | return Z_STREAM_ERROR; |
1162 | #else |
1163 | deflate_state *ds; |
1164 | deflate_state *ss; |
b24e7fce |
1165 | |
1166 | |
1167 | if (deflateStateCheck(source) || dest == Z_NULL) { |
1168 | return Z_STREAM_ERROR; |
1169 | } |
1170 | |
1171 | ss = source->state; |
1172 | |
1173 | zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); |
1174 | |
1175 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); |
1176 | if (ds == Z_NULL) return Z_MEM_ERROR; |
1177 | dest->state = (struct internal_state FAR *) ds; |
1178 | zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state)); |
1179 | ds->strm = dest; |
1180 | |
1181 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); |
1182 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); |
1183 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); |
9e052883 |
1184 | ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4); |
b24e7fce |
1185 | |
1186 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || |
1187 | ds->pending_buf == Z_NULL) { |
1188 | deflateEnd (dest); |
1189 | return Z_MEM_ERROR; |
1190 | } |
1191 | /* following zmemcpy do not work for 16-bit MSDOS */ |
1192 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); |
1193 | zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos)); |
1194 | zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos)); |
1195 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); |
1196 | |
1197 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); |
9e052883 |
1198 | ds->sym_buf = ds->pending_buf + ds->lit_bufsize; |
b24e7fce |
1199 | |
1200 | ds->l_desc.dyn_tree = ds->dyn_ltree; |
1201 | ds->d_desc.dyn_tree = ds->dyn_dtree; |
1202 | ds->bl_desc.dyn_tree = ds->bl_tree; |
1203 | |
1204 | return Z_OK; |
1205 | #endif /* MAXSEG_64K */ |
1206 | } |
1207 | |
1208 | /* =========================================================================== |
1209 | * Read a new buffer from the current input stream, update the adler32 |
1210 | * and total number of bytes read. All deflate() input goes through |
1211 | * this function so some applications may wish to modify it to avoid |
1212 | * allocating a large strm->next_in buffer and copying from it. |
1213 | * (See also flush_pending()). |
1214 | */ |
1215 | local unsigned read_buf(strm, buf, size) |
1216 | z_streamp strm; |
1217 | Bytef *buf; |
1218 | unsigned size; |
1219 | { |
1220 | unsigned len = strm->avail_in; |
1221 | |
1222 | if (len > size) len = size; |
1223 | if (len == 0) return 0; |
1224 | |
1225 | strm->avail_in -= len; |
1226 | |
1227 | zmemcpy(buf, strm->next_in, len); |
1228 | if (strm->state->wrap == 1) { |
1229 | strm->adler = adler32(strm->adler, buf, len); |
1230 | } |
1231 | #ifdef GZIP |
1232 | else if (strm->state->wrap == 2) { |
1233 | strm->adler = crc32(strm->adler, buf, len); |
1234 | } |
1235 | #endif |
1236 | strm->next_in += len; |
1237 | strm->total_in += len; |
1238 | |
1239 | return len; |
1240 | } |
1241 | |
1242 | /* =========================================================================== |
1243 | * Initialize the "longest match" routines for a new zlib stream |
1244 | */ |
9e052883 |
1245 | local void lm_init(s) |
b24e7fce |
1246 | deflate_state *s; |
1247 | { |
1248 | s->window_size = (ulg)2L*s->w_size; |
1249 | |
1250 | CLEAR_HASH(s); |
1251 | |
1252 | /* Set the default configuration parameters: |
1253 | */ |
1254 | s->max_lazy_match = configuration_table[s->level].max_lazy; |
1255 | s->good_match = configuration_table[s->level].good_length; |
1256 | s->nice_match = configuration_table[s->level].nice_length; |
1257 | s->max_chain_length = configuration_table[s->level].max_chain; |
1258 | |
1259 | s->strstart = 0; |
1260 | s->block_start = 0L; |
1261 | s->lookahead = 0; |
1262 | s->insert = 0; |
1263 | s->match_length = s->prev_length = MIN_MATCH-1; |
1264 | s->match_available = 0; |
1265 | s->ins_h = 0; |
b24e7fce |
1266 | } |
1267 | |
1268 | #ifndef FASTEST |
1269 | /* =========================================================================== |
1270 | * Set match_start to the longest match starting at the given string and |
1271 | * return its length. Matches shorter or equal to prev_length are discarded, |
1272 | * in which case the result is equal to prev_length and match_start is |
1273 | * garbage. |
1274 | * IN assertions: cur_match is the head of the hash chain for the current |
1275 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 |
1276 | * OUT assertion: the match length is not greater than s->lookahead. |
1277 | */ |
b24e7fce |
1278 | local uInt longest_match(s, cur_match) |
1279 | deflate_state *s; |
1280 | IPos cur_match; /* current match */ |
1281 | { |
1282 | unsigned chain_length = s->max_chain_length;/* max hash chain length */ |
1283 | register Bytef *scan = s->window + s->strstart; /* current string */ |
1284 | register Bytef *match; /* matched string */ |
1285 | register int len; /* length of current match */ |
1286 | int best_len = (int)s->prev_length; /* best match length so far */ |
1287 | int nice_match = s->nice_match; /* stop if match long enough */ |
1288 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ? |
1289 | s->strstart - (IPos)MAX_DIST(s) : NIL; |
1290 | /* Stop when cur_match becomes <= limit. To simplify the code, |
1291 | * we prevent matches with the string of window index 0. |
1292 | */ |
1293 | Posf *prev = s->prev; |
1294 | uInt wmask = s->w_mask; |
1295 | |
1296 | #ifdef UNALIGNED_OK |
1297 | /* Compare two bytes at a time. Note: this is not always beneficial. |
1298 | * Try with and without -DUNALIGNED_OK to check. |
1299 | */ |
1300 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; |
1301 | register ush scan_start = *(ushf*)scan; |
9e052883 |
1302 | register ush scan_end = *(ushf*)(scan + best_len - 1); |
b24e7fce |
1303 | #else |
1304 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; |
9e052883 |
1305 | register Byte scan_end1 = scan[best_len - 1]; |
b24e7fce |
1306 | register Byte scan_end = scan[best_len]; |
1307 | #endif |
1308 | |
1309 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. |
1310 | * It is easy to get rid of this optimization if necessary. |
1311 | */ |
1312 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); |
1313 | |
1314 | /* Do not waste too much time if we already have a good match: */ |
1315 | if (s->prev_length >= s->good_match) { |
1316 | chain_length >>= 2; |
1317 | } |
1318 | /* Do not look for matches beyond the end of the input. This is necessary |
1319 | * to make deflate deterministic. |
1320 | */ |
1321 | if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead; |
1322 | |
9e052883 |
1323 | Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
1324 | "need lookahead"); |
b24e7fce |
1325 | |
1326 | do { |
1327 | Assert(cur_match < s->strstart, "no future"); |
1328 | match = s->window + cur_match; |
1329 | |
1330 | /* Skip to next match if the match length cannot increase |
1331 | * or if the match length is less than 2. Note that the checks below |
1332 | * for insufficient lookahead only occur occasionally for performance |
1333 | * reasons. Therefore uninitialized memory will be accessed, and |
1334 | * conditional jumps will be made that depend on those values. |
1335 | * However the length of the match is limited to the lookahead, so |
1336 | * the output of deflate is not affected by the uninitialized values. |
1337 | */ |
1338 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) |
1339 | /* This code assumes sizeof(unsigned short) == 2. Do not use |
1340 | * UNALIGNED_OK if your compiler uses a different size. |
1341 | */ |
9e052883 |
1342 | if (*(ushf*)(match + best_len - 1) != scan_end || |
b24e7fce |
1343 | *(ushf*)match != scan_start) continue; |
1344 | |
1345 | /* It is not necessary to compare scan[2] and match[2] since they are |
1346 | * always equal when the other bytes match, given that the hash keys |
1347 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at |
9e052883 |
1348 | * strstart + 3, + 5, up to strstart + 257. We check for insufficient |
b24e7fce |
1349 | * lookahead only every 4th comparison; the 128th check will be made |
9e052883 |
1350 | * at strstart + 257. If MAX_MATCH-2 is not a multiple of 8, it is |
b24e7fce |
1351 | * necessary to put more guard bytes at the end of the window, or |
1352 | * to check more often for insufficient lookahead. |
1353 | */ |
1354 | Assert(scan[2] == match[2], "scan[2]?"); |
1355 | scan++, match++; |
1356 | do { |
9e052883 |
1357 | } while (*(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
1358 | *(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
1359 | *(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
1360 | *(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
b24e7fce |
1361 | scan < strend); |
1362 | /* The funny "do {}" generates better code on most compilers */ |
1363 | |
9e052883 |
1364 | /* Here, scan <= window + strstart + 257 */ |
1365 | Assert(scan <= s->window + (unsigned)(s->window_size - 1), |
1366 | "wild scan"); |
b24e7fce |
1367 | if (*scan == *match) scan++; |
1368 | |
9e052883 |
1369 | len = (MAX_MATCH - 1) - (int)(strend - scan); |
b24e7fce |
1370 | scan = strend - (MAX_MATCH-1); |
1371 | |
1372 | #else /* UNALIGNED_OK */ |
1373 | |
9e052883 |
1374 | if (match[best_len] != scan_end || |
1375 | match[best_len - 1] != scan_end1 || |
1376 | *match != *scan || |
1377 | *++match != scan[1]) continue; |
b24e7fce |
1378 | |
9e052883 |
1379 | /* The check at best_len - 1 can be removed because it will be made |
b24e7fce |
1380 | * again later. (This heuristic is not always a win.) |
1381 | * It is not necessary to compare scan[2] and match[2] since they |
1382 | * are always equal when the other bytes match, given that |
1383 | * the hash keys are equal and that HASH_BITS >= 8. |
1384 | */ |
1385 | scan += 2, match++; |
1386 | Assert(*scan == *match, "match[2]?"); |
1387 | |
1388 | /* We check for insufficient lookahead only every 8th comparison; |
9e052883 |
1389 | * the 256th check will be made at strstart + 258. |
b24e7fce |
1390 | */ |
1391 | do { |
1392 | } while (*++scan == *++match && *++scan == *++match && |
1393 | *++scan == *++match && *++scan == *++match && |
1394 | *++scan == *++match && *++scan == *++match && |
1395 | *++scan == *++match && *++scan == *++match && |
1396 | scan < strend); |
1397 | |
9e052883 |
1398 | Assert(scan <= s->window + (unsigned)(s->window_size - 1), |
1399 | "wild scan"); |
b24e7fce |
1400 | |
1401 | len = MAX_MATCH - (int)(strend - scan); |
1402 | scan = strend - MAX_MATCH; |
1403 | |
1404 | #endif /* UNALIGNED_OK */ |
1405 | |
1406 | if (len > best_len) { |
1407 | s->match_start = cur_match; |
1408 | best_len = len; |
1409 | if (len >= nice_match) break; |
1410 | #ifdef UNALIGNED_OK |
9e052883 |
1411 | scan_end = *(ushf*)(scan + best_len - 1); |
b24e7fce |
1412 | #else |
9e052883 |
1413 | scan_end1 = scan[best_len - 1]; |
b24e7fce |
1414 | scan_end = scan[best_len]; |
1415 | #endif |
1416 | } |
1417 | } while ((cur_match = prev[cur_match & wmask]) > limit |
1418 | && --chain_length != 0); |
1419 | |
1420 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len; |
1421 | return s->lookahead; |
1422 | } |
b24e7fce |
1423 | |
1424 | #else /* FASTEST */ |
1425 | |
1426 | /* --------------------------------------------------------------------------- |
1427 | * Optimized version for FASTEST only |
1428 | */ |
1429 | local uInt longest_match(s, cur_match) |
1430 | deflate_state *s; |
1431 | IPos cur_match; /* current match */ |
1432 | { |
1433 | register Bytef *scan = s->window + s->strstart; /* current string */ |
1434 | register Bytef *match; /* matched string */ |
1435 | register int len; /* length of current match */ |
1436 | register Bytef *strend = s->window + s->strstart + MAX_MATCH; |
1437 | |
1438 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. |
1439 | * It is easy to get rid of this optimization if necessary. |
1440 | */ |
1441 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); |
1442 | |
9e052883 |
1443 | Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
1444 | "need lookahead"); |
b24e7fce |
1445 | |
1446 | Assert(cur_match < s->strstart, "no future"); |
1447 | |
1448 | match = s->window + cur_match; |
1449 | |
1450 | /* Return failure if the match length is less than 2: |
1451 | */ |
1452 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; |
1453 | |
9e052883 |
1454 | /* The check at best_len - 1 can be removed because it will be made |
b24e7fce |
1455 | * again later. (This heuristic is not always a win.) |
1456 | * It is not necessary to compare scan[2] and match[2] since they |
1457 | * are always equal when the other bytes match, given that |
1458 | * the hash keys are equal and that HASH_BITS >= 8. |
1459 | */ |
1460 | scan += 2, match += 2; |
1461 | Assert(*scan == *match, "match[2]?"); |
1462 | |
1463 | /* We check for insufficient lookahead only every 8th comparison; |
9e052883 |
1464 | * the 256th check will be made at strstart + 258. |
b24e7fce |
1465 | */ |
1466 | do { |
1467 | } while (*++scan == *++match && *++scan == *++match && |
1468 | *++scan == *++match && *++scan == *++match && |
1469 | *++scan == *++match && *++scan == *++match && |
1470 | *++scan == *++match && *++scan == *++match && |
1471 | scan < strend); |
1472 | |
9e052883 |
1473 | Assert(scan <= s->window + (unsigned)(s->window_size - 1), "wild scan"); |
b24e7fce |
1474 | |
1475 | len = MAX_MATCH - (int)(strend - scan); |
1476 | |
1477 | if (len < MIN_MATCH) return MIN_MATCH - 1; |
1478 | |
1479 | s->match_start = cur_match; |
1480 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; |
1481 | } |
1482 | |
1483 | #endif /* FASTEST */ |
1484 | |
1485 | #ifdef ZLIB_DEBUG |
1486 | |
1487 | #define EQUAL 0 |
1488 | /* result of memcmp for equal strings */ |
1489 | |
1490 | /* =========================================================================== |
1491 | * Check that the match at match_start is indeed a match. |
1492 | */ |
1493 | local void check_match(s, start, match, length) |
1494 | deflate_state *s; |
1495 | IPos start, match; |
1496 | int length; |
1497 | { |
1498 | /* check that the match is indeed a match */ |
1499 | if (zmemcmp(s->window + match, |
1500 | s->window + start, length) != EQUAL) { |
1501 | fprintf(stderr, " start %u, match %u, length %d\n", |
1502 | start, match, length); |
1503 | do { |
1504 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); |
1505 | } while (--length != 0); |
1506 | z_error("invalid match"); |
1507 | } |
1508 | if (z_verbose > 1) { |
9e052883 |
1509 | fprintf(stderr,"\\[%d,%d]", start - match, length); |
b24e7fce |
1510 | do { putc(s->window[start++], stderr); } while (--length != 0); |
1511 | } |
1512 | } |
1513 | #else |
1514 | # define check_match(s, start, match, length) |
1515 | #endif /* ZLIB_DEBUG */ |
1516 | |
1517 | /* =========================================================================== |
1518 | * Fill the window when the lookahead becomes insufficient. |
1519 | * Updates strstart and lookahead. |
1520 | * |
1521 | * IN assertion: lookahead < MIN_LOOKAHEAD |
1522 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD |
1523 | * At least one byte has been read, or avail_in == 0; reads are |
1524 | * performed for at least two bytes (required for the zip translate_eol |
1525 | * option -- not supported here). |
1526 | */ |
1527 | local void fill_window(s) |
1528 | deflate_state *s; |
1529 | { |
1530 | unsigned n; |
1531 | unsigned more; /* Amount of free space at the end of the window. */ |
1532 | uInt wsize = s->w_size; |
1533 | |
1534 | Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); |
1535 | |
1536 | do { |
1537 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); |
1538 | |
1539 | /* Deal with !@#$% 64K limit: */ |
1540 | if (sizeof(int) <= 2) { |
1541 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) { |
1542 | more = wsize; |
1543 | |
1544 | } else if (more == (unsigned)(-1)) { |
1545 | /* Very unlikely, but possible on 16 bit machine if |
1546 | * strstart == 0 && lookahead == 1 (input done a byte at time) |
1547 | */ |
1548 | more--; |
1549 | } |
1550 | } |
1551 | |
1552 | /* If the window is almost full and there is insufficient lookahead, |
1553 | * move the upper half to the lower one to make room in the upper half. |
1554 | */ |
9e052883 |
1555 | if (s->strstart >= wsize + MAX_DIST(s)) { |
b24e7fce |
1556 | |
9e052883 |
1557 | zmemcpy(s->window, s->window + wsize, (unsigned)wsize - more); |
b24e7fce |
1558 | s->match_start -= wsize; |
1559 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ |
1560 | s->block_start -= (long) wsize; |
9e052883 |
1561 | if (s->insert > s->strstart) |
1562 | s->insert = s->strstart; |
b24e7fce |
1563 | slide_hash(s); |
1564 | more += wsize; |
1565 | } |
1566 | if (s->strm->avail_in == 0) break; |
1567 | |
1568 | /* If there was no sliding: |
1569 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && |
1570 | * more == window_size - lookahead - strstart |
1571 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) |
1572 | * => more >= window_size - 2*WSIZE + 2 |
1573 | * In the BIG_MEM or MMAP case (not yet supported), |
1574 | * window_size == input_size + MIN_LOOKAHEAD && |
1575 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. |
1576 | * Otherwise, window_size == 2*WSIZE so more >= 2. |
1577 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2. |
1578 | */ |
1579 | Assert(more >= 2, "more < 2"); |
1580 | |
1581 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); |
1582 | s->lookahead += n; |
1583 | |
1584 | /* Initialize the hash value now that we have some input: */ |
1585 | if (s->lookahead + s->insert >= MIN_MATCH) { |
1586 | uInt str = s->strstart - s->insert; |
1587 | s->ins_h = s->window[str]; |
1588 | UPDATE_HASH(s, s->ins_h, s->window[str + 1]); |
1589 | #if MIN_MATCH != 3 |
1590 | Call UPDATE_HASH() MIN_MATCH-3 more times |
1591 | #endif |
1592 | while (s->insert) { |
1593 | UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); |
1594 | #ifndef FASTEST |
1595 | s->prev[str & s->w_mask] = s->head[s->ins_h]; |
1596 | #endif |
1597 | s->head[s->ins_h] = (Pos)str; |
1598 | str++; |
1599 | s->insert--; |
1600 | if (s->lookahead + s->insert < MIN_MATCH) |
1601 | break; |
1602 | } |
1603 | } |
1604 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, |
1605 | * but this is not important since only literal bytes will be emitted. |
1606 | */ |
1607 | |
1608 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); |
1609 | |
1610 | /* If the WIN_INIT bytes after the end of the current data have never been |
1611 | * written, then zero those bytes in order to avoid memory check reports of |
1612 | * the use of uninitialized (or uninitialised as Julian writes) bytes by |
1613 | * the longest match routines. Update the high water mark for the next |
1614 | * time through here. WIN_INIT is set to MAX_MATCH since the longest match |
1615 | * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. |
1616 | */ |
1617 | if (s->high_water < s->window_size) { |
1618 | ulg curr = s->strstart + (ulg)(s->lookahead); |
1619 | ulg init; |
1620 | |
1621 | if (s->high_water < curr) { |
1622 | /* Previous high water mark below current data -- zero WIN_INIT |
1623 | * bytes or up to end of window, whichever is less. |
1624 | */ |
1625 | init = s->window_size - curr; |
1626 | if (init > WIN_INIT) |
1627 | init = WIN_INIT; |
1628 | zmemzero(s->window + curr, (unsigned)init); |
1629 | s->high_water = curr + init; |
1630 | } |
1631 | else if (s->high_water < (ulg)curr + WIN_INIT) { |
1632 | /* High water mark at or above current data, but below current data |
1633 | * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up |
1634 | * to end of window, whichever is less. |
1635 | */ |
1636 | init = (ulg)curr + WIN_INIT - s->high_water; |
1637 | if (init > s->window_size - s->high_water) |
1638 | init = s->window_size - s->high_water; |
1639 | zmemzero(s->window + s->high_water, (unsigned)init); |
1640 | s->high_water += init; |
1641 | } |
1642 | } |
1643 | |
1644 | Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
1645 | "not enough room for search"); |
1646 | } |
1647 | |
1648 | /* =========================================================================== |
1649 | * Flush the current block, with given end-of-file flag. |
1650 | * IN assertion: strstart is set to the end of the current match. |
1651 | */ |
1652 | #define FLUSH_BLOCK_ONLY(s, last) { \ |
1653 | _tr_flush_block(s, (s->block_start >= 0L ? \ |
1654 | (charf *)&s->window[(unsigned)s->block_start] : \ |
1655 | (charf *)Z_NULL), \ |
1656 | (ulg)((long)s->strstart - s->block_start), \ |
1657 | (last)); \ |
1658 | s->block_start = s->strstart; \ |
1659 | flush_pending(s->strm); \ |
1660 | Tracev((stderr,"[FLUSH]")); \ |
1661 | } |
1662 | |
1663 | /* Same but force premature exit if necessary. */ |
1664 | #define FLUSH_BLOCK(s, last) { \ |
1665 | FLUSH_BLOCK_ONLY(s, last); \ |
1666 | if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ |
1667 | } |
1668 | |
1669 | /* Maximum stored block length in deflate format (not including header). */ |
1670 | #define MAX_STORED 65535 |
1671 | |
1672 | /* Minimum of a and b. */ |
1673 | #define MIN(a, b) ((a) > (b) ? (b) : (a)) |
1674 | |
1675 | /* =========================================================================== |
1676 | * Copy without compression as much as possible from the input stream, return |
1677 | * the current block state. |
1678 | * |
1679 | * In case deflateParams() is used to later switch to a non-zero compression |
1680 | * level, s->matches (otherwise unused when storing) keeps track of the number |
1681 | * of hash table slides to perform. If s->matches is 1, then one hash table |
1682 | * slide will be done when switching. If s->matches is 2, the maximum value |
1683 | * allowed here, then the hash table will be cleared, since two or more slides |
1684 | * is the same as a clear. |
1685 | * |
1686 | * deflate_stored() is written to minimize the number of times an input byte is |
1687 | * copied. It is most efficient with large input and output buffers, which |
9e052883 |
1688 | * maximizes the opportunities to have a single copy from next_in to next_out. |
b24e7fce |
1689 | */ |
1690 | local block_state deflate_stored(s, flush) |
1691 | deflate_state *s; |
1692 | int flush; |
1693 | { |
1694 | /* Smallest worthy block size when not flushing or finishing. By default |
1695 | * this is 32K. This can be as small as 507 bytes for memLevel == 1. For |
1696 | * large input and output buffers, the stored block size will be larger. |
1697 | */ |
1698 | unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size); |
1699 | |
1700 | /* Copy as many min_block or larger stored blocks directly to next_out as |
1701 | * possible. If flushing, copy the remaining available input to next_out as |
1702 | * stored blocks, if there is enough space. |
1703 | */ |
1704 | unsigned len, left, have, last = 0; |
1705 | unsigned used = s->strm->avail_in; |
1706 | do { |
1707 | /* Set len to the maximum size block that we can copy directly with the |
1708 | * available input data and output space. Set left to how much of that |
1709 | * would be copied from what's left in the window. |
1710 | */ |
1711 | len = MAX_STORED; /* maximum deflate stored block length */ |
1712 | have = (s->bi_valid + 42) >> 3; /* number of header bytes */ |
1713 | if (s->strm->avail_out < have) /* need room for header */ |
1714 | break; |
1715 | /* maximum stored block length that will fit in avail_out: */ |
1716 | have = s->strm->avail_out - have; |
1717 | left = s->strstart - s->block_start; /* bytes left in window */ |
1718 | if (len > (ulg)left + s->strm->avail_in) |
1719 | len = left + s->strm->avail_in; /* limit len to the input */ |
1720 | if (len > have) |
1721 | len = have; /* limit len to the output */ |
1722 | |
1723 | /* If the stored block would be less than min_block in length, or if |
1724 | * unable to copy all of the available input when flushing, then try |
1725 | * copying to the window and the pending buffer instead. Also don't |
1726 | * write an empty block when flushing -- deflate() does that. |
1727 | */ |
1728 | if (len < min_block && ((len == 0 && flush != Z_FINISH) || |
1729 | flush == Z_NO_FLUSH || |
1730 | len != left + s->strm->avail_in)) |
1731 | break; |
1732 | |
1733 | /* Make a dummy stored block in pending to get the header bytes, |
1734 | * including any pending bits. This also updates the debugging counts. |
1735 | */ |
1736 | last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0; |
1737 | _tr_stored_block(s, (char *)0, 0L, last); |
1738 | |
1739 | /* Replace the lengths in the dummy stored block with len. */ |
1740 | s->pending_buf[s->pending - 4] = len; |
1741 | s->pending_buf[s->pending - 3] = len >> 8; |
1742 | s->pending_buf[s->pending - 2] = ~len; |
1743 | s->pending_buf[s->pending - 1] = ~len >> 8; |
1744 | |
1745 | /* Write the stored block header bytes. */ |
1746 | flush_pending(s->strm); |
1747 | |
1748 | #ifdef ZLIB_DEBUG |
1749 | /* Update debugging counts for the data about to be copied. */ |
1750 | s->compressed_len += len << 3; |
1751 | s->bits_sent += len << 3; |
1752 | #endif |
1753 | |
1754 | /* Copy uncompressed bytes from the window to next_out. */ |
1755 | if (left) { |
1756 | if (left > len) |
1757 | left = len; |
1758 | zmemcpy(s->strm->next_out, s->window + s->block_start, left); |
1759 | s->strm->next_out += left; |
1760 | s->strm->avail_out -= left; |
1761 | s->strm->total_out += left; |
1762 | s->block_start += left; |
1763 | len -= left; |
1764 | } |
1765 | |
1766 | /* Copy uncompressed bytes directly from next_in to next_out, updating |
1767 | * the check value. |
1768 | */ |
1769 | if (len) { |
1770 | read_buf(s->strm, s->strm->next_out, len); |
1771 | s->strm->next_out += len; |
1772 | s->strm->avail_out -= len; |
1773 | s->strm->total_out += len; |
1774 | } |
1775 | } while (last == 0); |
1776 | |
1777 | /* Update the sliding window with the last s->w_size bytes of the copied |
1778 | * data, or append all of the copied data to the existing window if less |
1779 | * than s->w_size bytes were copied. Also update the number of bytes to |
1780 | * insert in the hash tables, in the event that deflateParams() switches to |
1781 | * a non-zero compression level. |
1782 | */ |
1783 | used -= s->strm->avail_in; /* number of input bytes directly copied */ |
1784 | if (used) { |
1785 | /* If any input was used, then no unused input remains in the window, |
1786 | * therefore s->block_start == s->strstart. |
1787 | */ |
1788 | if (used >= s->w_size) { /* supplant the previous history */ |
1789 | s->matches = 2; /* clear hash */ |
1790 | zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); |
1791 | s->strstart = s->w_size; |
9e052883 |
1792 | s->insert = s->strstart; |
b24e7fce |
1793 | } |
1794 | else { |
1795 | if (s->window_size - s->strstart <= used) { |
1796 | /* Slide the window down. */ |
1797 | s->strstart -= s->w_size; |
1798 | zmemcpy(s->window, s->window + s->w_size, s->strstart); |
1799 | if (s->matches < 2) |
1800 | s->matches++; /* add a pending slide_hash() */ |
9e052883 |
1801 | if (s->insert > s->strstart) |
1802 | s->insert = s->strstart; |
b24e7fce |
1803 | } |
1804 | zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); |
1805 | s->strstart += used; |
9e052883 |
1806 | s->insert += MIN(used, s->w_size - s->insert); |
b24e7fce |
1807 | } |
1808 | s->block_start = s->strstart; |
b24e7fce |
1809 | } |
1810 | if (s->high_water < s->strstart) |
1811 | s->high_water = s->strstart; |
1812 | |
1813 | /* If the last block was written to next_out, then done. */ |
1814 | if (last) |
1815 | return finish_done; |
1816 | |
1817 | /* If flushing and all input has been consumed, then done. */ |
1818 | if (flush != Z_NO_FLUSH && flush != Z_FINISH && |
1819 | s->strm->avail_in == 0 && (long)s->strstart == s->block_start) |
1820 | return block_done; |
1821 | |
1822 | /* Fill the window with any remaining input. */ |
9e052883 |
1823 | have = s->window_size - s->strstart; |
b24e7fce |
1824 | if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { |
1825 | /* Slide the window down. */ |
1826 | s->block_start -= s->w_size; |
1827 | s->strstart -= s->w_size; |
1828 | zmemcpy(s->window, s->window + s->w_size, s->strstart); |
1829 | if (s->matches < 2) |
1830 | s->matches++; /* add a pending slide_hash() */ |
1831 | have += s->w_size; /* more space now */ |
9e052883 |
1832 | if (s->insert > s->strstart) |
1833 | s->insert = s->strstart; |
b24e7fce |
1834 | } |
1835 | if (have > s->strm->avail_in) |
1836 | have = s->strm->avail_in; |
1837 | if (have) { |
1838 | read_buf(s->strm, s->window + s->strstart, have); |
1839 | s->strstart += have; |
9e052883 |
1840 | s->insert += MIN(have, s->w_size - s->insert); |
b24e7fce |
1841 | } |
1842 | if (s->high_water < s->strstart) |
1843 | s->high_water = s->strstart; |
1844 | |
1845 | /* There was not enough avail_out to write a complete worthy or flushed |
1846 | * stored block to next_out. Write a stored block to pending instead, if we |
1847 | * have enough input for a worthy block, or if flushing and there is enough |
1848 | * room for the remaining input as a stored block in the pending buffer. |
1849 | */ |
1850 | have = (s->bi_valid + 42) >> 3; /* number of header bytes */ |
1851 | /* maximum stored block length that will fit in pending: */ |
1852 | have = MIN(s->pending_buf_size - have, MAX_STORED); |
1853 | min_block = MIN(have, s->w_size); |
1854 | left = s->strstart - s->block_start; |
1855 | if (left >= min_block || |
1856 | ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH && |
1857 | s->strm->avail_in == 0 && left <= have)) { |
1858 | len = MIN(left, have); |
1859 | last = flush == Z_FINISH && s->strm->avail_in == 0 && |
1860 | len == left ? 1 : 0; |
1861 | _tr_stored_block(s, (charf *)s->window + s->block_start, len, last); |
1862 | s->block_start += len; |
1863 | flush_pending(s->strm); |
1864 | } |
1865 | |
1866 | /* We've done all we can with the available input and output. */ |
1867 | return last ? finish_started : need_more; |
1868 | } |
1869 | |
1870 | /* =========================================================================== |
1871 | * Compress as much as possible from the input stream, return the current |
1872 | * block state. |
1873 | * This function does not perform lazy evaluation of matches and inserts |
1874 | * new strings in the dictionary only for unmatched strings or for short |
1875 | * matches. It is used only for the fast compression options. |
1876 | */ |
1877 | local block_state deflate_fast(s, flush) |
1878 | deflate_state *s; |
1879 | int flush; |
1880 | { |
1881 | IPos hash_head; /* head of the hash chain */ |
1882 | int bflush; /* set if current block must be flushed */ |
1883 | |
1884 | for (;;) { |
1885 | /* Make sure that we always have enough lookahead, except |
1886 | * at the end of the input file. We need MAX_MATCH bytes |
1887 | * for the next match, plus MIN_MATCH bytes to insert the |
1888 | * string following the next match. |
1889 | */ |
1890 | if (s->lookahead < MIN_LOOKAHEAD) { |
1891 | fill_window(s); |
1892 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { |
1893 | return need_more; |
1894 | } |
1895 | if (s->lookahead == 0) break; /* flush the current block */ |
1896 | } |
1897 | |
9e052883 |
1898 | /* Insert the string window[strstart .. strstart + 2] in the |
b24e7fce |
1899 | * dictionary, and set hash_head to the head of the hash chain: |
1900 | */ |
1901 | hash_head = NIL; |
1902 | if (s->lookahead >= MIN_MATCH) { |
1903 | INSERT_STRING(s, s->strstart, hash_head); |
1904 | } |
1905 | |
1906 | /* Find the longest match, discarding those <= prev_length. |
1907 | * At this point we have always match_length < MIN_MATCH |
1908 | */ |
1909 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { |
1910 | /* To simplify the code, we prevent matches with the string |
1911 | * of window index 0 (in particular we have to avoid a match |
1912 | * of the string with itself at the start of the input file). |
1913 | */ |
1914 | s->match_length = longest_match (s, hash_head); |
1915 | /* longest_match() sets match_start */ |
1916 | } |
1917 | if (s->match_length >= MIN_MATCH) { |
1918 | check_match(s, s->strstart, s->match_start, s->match_length); |
1919 | |
1920 | _tr_tally_dist(s, s->strstart - s->match_start, |
1921 | s->match_length - MIN_MATCH, bflush); |
1922 | |
1923 | s->lookahead -= s->match_length; |
1924 | |
1925 | /* Insert new strings in the hash table only if the match length |
1926 | * is not too large. This saves time but degrades compression. |
1927 | */ |
1928 | #ifndef FASTEST |
1929 | if (s->match_length <= s->max_insert_length && |
1930 | s->lookahead >= MIN_MATCH) { |
1931 | s->match_length--; /* string at strstart already in table */ |
1932 | do { |
1933 | s->strstart++; |
1934 | INSERT_STRING(s, s->strstart, hash_head); |
1935 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are |
1936 | * always MIN_MATCH bytes ahead. |
1937 | */ |
1938 | } while (--s->match_length != 0); |
1939 | s->strstart++; |
1940 | } else |
1941 | #endif |
1942 | { |
1943 | s->strstart += s->match_length; |
1944 | s->match_length = 0; |
1945 | s->ins_h = s->window[s->strstart]; |
9e052883 |
1946 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart + 1]); |
b24e7fce |
1947 | #if MIN_MATCH != 3 |
1948 | Call UPDATE_HASH() MIN_MATCH-3 more times |
1949 | #endif |
1950 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not |
1951 | * matter since it will be recomputed at next deflate call. |
1952 | */ |
1953 | } |
1954 | } else { |
1955 | /* No match, output a literal byte */ |
1956 | Tracevv((stderr,"%c", s->window[s->strstart])); |
9e052883 |
1957 | _tr_tally_lit(s, s->window[s->strstart], bflush); |
b24e7fce |
1958 | s->lookahead--; |
1959 | s->strstart++; |
1960 | } |
1961 | if (bflush) FLUSH_BLOCK(s, 0); |
1962 | } |
1963 | s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; |
1964 | if (flush == Z_FINISH) { |
1965 | FLUSH_BLOCK(s, 1); |
1966 | return finish_done; |
1967 | } |
9e052883 |
1968 | if (s->sym_next) |
b24e7fce |
1969 | FLUSH_BLOCK(s, 0); |
1970 | return block_done; |
1971 | } |
1972 | |
1973 | #ifndef FASTEST |
1974 | /* =========================================================================== |
1975 | * Same as above, but achieves better compression. We use a lazy |
1976 | * evaluation for matches: a match is finally adopted only if there is |
1977 | * no better match at the next window position. |
1978 | */ |
1979 | local block_state deflate_slow(s, flush) |
1980 | deflate_state *s; |
1981 | int flush; |
1982 | { |
1983 | IPos hash_head; /* head of hash chain */ |
1984 | int bflush; /* set if current block must be flushed */ |
1985 | |
1986 | /* Process the input block. */ |
1987 | for (;;) { |
1988 | /* Make sure that we always have enough lookahead, except |
1989 | * at the end of the input file. We need MAX_MATCH bytes |
1990 | * for the next match, plus MIN_MATCH bytes to insert the |
1991 | * string following the next match. |
1992 | */ |
1993 | if (s->lookahead < MIN_LOOKAHEAD) { |
1994 | fill_window(s); |
1995 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { |
1996 | return need_more; |
1997 | } |
1998 | if (s->lookahead == 0) break; /* flush the current block */ |
1999 | } |
2000 | |
9e052883 |
2001 | /* Insert the string window[strstart .. strstart + 2] in the |
b24e7fce |
2002 | * dictionary, and set hash_head to the head of the hash chain: |
2003 | */ |
2004 | hash_head = NIL; |
2005 | if (s->lookahead >= MIN_MATCH) { |
2006 | INSERT_STRING(s, s->strstart, hash_head); |
2007 | } |
2008 | |
2009 | /* Find the longest match, discarding those <= prev_length. |
2010 | */ |
2011 | s->prev_length = s->match_length, s->prev_match = s->match_start; |
2012 | s->match_length = MIN_MATCH-1; |
2013 | |
2014 | if (hash_head != NIL && s->prev_length < s->max_lazy_match && |
2015 | s->strstart - hash_head <= MAX_DIST(s)) { |
2016 | /* To simplify the code, we prevent matches with the string |
2017 | * of window index 0 (in particular we have to avoid a match |
2018 | * of the string with itself at the start of the input file). |
2019 | */ |
2020 | s->match_length = longest_match (s, hash_head); |
2021 | /* longest_match() sets match_start */ |
2022 | |
2023 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED |
2024 | #if TOO_FAR <= 32767 |
2025 | || (s->match_length == MIN_MATCH && |
2026 | s->strstart - s->match_start > TOO_FAR) |
2027 | #endif |
2028 | )) { |
2029 | |
2030 | /* If prev_match is also MIN_MATCH, match_start is garbage |
2031 | * but we will ignore the current match anyway. |
2032 | */ |
2033 | s->match_length = MIN_MATCH-1; |
2034 | } |
2035 | } |
2036 | /* If there was a match at the previous step and the current |
2037 | * match is not better, output the previous match: |
2038 | */ |
2039 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { |
2040 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; |
2041 | /* Do not insert strings in hash table beyond this. */ |
2042 | |
9e052883 |
2043 | check_match(s, s->strstart - 1, s->prev_match, s->prev_length); |
b24e7fce |
2044 | |
9e052883 |
2045 | _tr_tally_dist(s, s->strstart - 1 - s->prev_match, |
b24e7fce |
2046 | s->prev_length - MIN_MATCH, bflush); |
2047 | |
2048 | /* Insert in hash table all strings up to the end of the match. |
9e052883 |
2049 | * strstart - 1 and strstart are already inserted. If there is not |
b24e7fce |
2050 | * enough lookahead, the last two strings are not inserted in |
2051 | * the hash table. |
2052 | */ |
9e052883 |
2053 | s->lookahead -= s->prev_length - 1; |
b24e7fce |
2054 | s->prev_length -= 2; |
2055 | do { |
2056 | if (++s->strstart <= max_insert) { |
2057 | INSERT_STRING(s, s->strstart, hash_head); |
2058 | } |
2059 | } while (--s->prev_length != 0); |
2060 | s->match_available = 0; |
2061 | s->match_length = MIN_MATCH-1; |
2062 | s->strstart++; |
2063 | |
2064 | if (bflush) FLUSH_BLOCK(s, 0); |
2065 | |
2066 | } else if (s->match_available) { |
2067 | /* If there was no match at the previous position, output a |
2068 | * single literal. If there was a match but the current match |
2069 | * is longer, truncate the previous match to a single literal. |
2070 | */ |
9e052883 |
2071 | Tracevv((stderr,"%c", s->window[s->strstart - 1])); |
2072 | _tr_tally_lit(s, s->window[s->strstart - 1], bflush); |
b24e7fce |
2073 | if (bflush) { |
2074 | FLUSH_BLOCK_ONLY(s, 0); |
2075 | } |
2076 | s->strstart++; |
2077 | s->lookahead--; |
2078 | if (s->strm->avail_out == 0) return need_more; |
2079 | } else { |
2080 | /* There is no previous match to compare with, wait for |
2081 | * the next step to decide. |
2082 | */ |
2083 | s->match_available = 1; |
2084 | s->strstart++; |
2085 | s->lookahead--; |
2086 | } |
2087 | } |
2088 | Assert (flush != Z_NO_FLUSH, "no flush?"); |
2089 | if (s->match_available) { |
9e052883 |
2090 | Tracevv((stderr,"%c", s->window[s->strstart - 1])); |
2091 | _tr_tally_lit(s, s->window[s->strstart - 1], bflush); |
b24e7fce |
2092 | s->match_available = 0; |
2093 | } |
2094 | s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; |
2095 | if (flush == Z_FINISH) { |
2096 | FLUSH_BLOCK(s, 1); |
2097 | return finish_done; |
2098 | } |
9e052883 |
2099 | if (s->sym_next) |
b24e7fce |
2100 | FLUSH_BLOCK(s, 0); |
2101 | return block_done; |
2102 | } |
2103 | #endif /* FASTEST */ |
2104 | |
2105 | /* =========================================================================== |
2106 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance |
2107 | * one. Do not maintain a hash table. (It will be regenerated if this run of |
2108 | * deflate switches away from Z_RLE.) |
2109 | */ |
2110 | local block_state deflate_rle(s, flush) |
2111 | deflate_state *s; |
2112 | int flush; |
2113 | { |
2114 | int bflush; /* set if current block must be flushed */ |
2115 | uInt prev; /* byte at distance one to match */ |
2116 | Bytef *scan, *strend; /* scan goes up to strend for length of run */ |
2117 | |
2118 | for (;;) { |
2119 | /* Make sure that we always have enough lookahead, except |
2120 | * at the end of the input file. We need MAX_MATCH bytes |
2121 | * for the longest run, plus one for the unrolled loop. |
2122 | */ |
2123 | if (s->lookahead <= MAX_MATCH) { |
2124 | fill_window(s); |
2125 | if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { |
2126 | return need_more; |
2127 | } |
2128 | if (s->lookahead == 0) break; /* flush the current block */ |
2129 | } |
2130 | |
2131 | /* See how many times the previous byte repeats */ |
2132 | s->match_length = 0; |
2133 | if (s->lookahead >= MIN_MATCH && s->strstart > 0) { |
2134 | scan = s->window + s->strstart - 1; |
2135 | prev = *scan; |
2136 | if (prev == *++scan && prev == *++scan && prev == *++scan) { |
2137 | strend = s->window + s->strstart + MAX_MATCH; |
2138 | do { |
2139 | } while (prev == *++scan && prev == *++scan && |
2140 | prev == *++scan && prev == *++scan && |
2141 | prev == *++scan && prev == *++scan && |
2142 | prev == *++scan && prev == *++scan && |
2143 | scan < strend); |
2144 | s->match_length = MAX_MATCH - (uInt)(strend - scan); |
2145 | if (s->match_length > s->lookahead) |
2146 | s->match_length = s->lookahead; |
2147 | } |
9e052883 |
2148 | Assert(scan <= s->window + (uInt)(s->window_size - 1), |
2149 | "wild scan"); |
b24e7fce |
2150 | } |
2151 | |
2152 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */ |
2153 | if (s->match_length >= MIN_MATCH) { |
2154 | check_match(s, s->strstart, s->strstart - 1, s->match_length); |
2155 | |
2156 | _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); |
2157 | |
2158 | s->lookahead -= s->match_length; |
2159 | s->strstart += s->match_length; |
2160 | s->match_length = 0; |
2161 | } else { |
2162 | /* No match, output a literal byte */ |
2163 | Tracevv((stderr,"%c", s->window[s->strstart])); |
9e052883 |
2164 | _tr_tally_lit(s, s->window[s->strstart], bflush); |
b24e7fce |
2165 | s->lookahead--; |
2166 | s->strstart++; |
2167 | } |
2168 | if (bflush) FLUSH_BLOCK(s, 0); |
2169 | } |
2170 | s->insert = 0; |
2171 | if (flush == Z_FINISH) { |
2172 | FLUSH_BLOCK(s, 1); |
2173 | return finish_done; |
2174 | } |
9e052883 |
2175 | if (s->sym_next) |
b24e7fce |
2176 | FLUSH_BLOCK(s, 0); |
2177 | return block_done; |
2178 | } |
2179 | |
2180 | /* =========================================================================== |
2181 | * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. |
2182 | * (It will be regenerated if this run of deflate switches away from Huffman.) |
2183 | */ |
2184 | local block_state deflate_huff(s, flush) |
2185 | deflate_state *s; |
2186 | int flush; |
2187 | { |
2188 | int bflush; /* set if current block must be flushed */ |
2189 | |
2190 | for (;;) { |
2191 | /* Make sure that we have a literal to write. */ |
2192 | if (s->lookahead == 0) { |
2193 | fill_window(s); |
2194 | if (s->lookahead == 0) { |
2195 | if (flush == Z_NO_FLUSH) |
2196 | return need_more; |
2197 | break; /* flush the current block */ |
2198 | } |
2199 | } |
2200 | |
2201 | /* Output a literal byte */ |
2202 | s->match_length = 0; |
2203 | Tracevv((stderr,"%c", s->window[s->strstart])); |
9e052883 |
2204 | _tr_tally_lit(s, s->window[s->strstart], bflush); |
b24e7fce |
2205 | s->lookahead--; |
2206 | s->strstart++; |
2207 | if (bflush) FLUSH_BLOCK(s, 0); |
2208 | } |
2209 | s->insert = 0; |
2210 | if (flush == Z_FINISH) { |
2211 | FLUSH_BLOCK(s, 1); |
2212 | return finish_done; |
2213 | } |
9e052883 |
2214 | if (s->sym_next) |
b24e7fce |
2215 | FLUSH_BLOCK(s, 0); |
2216 | return block_done; |
2217 | } |