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Source at commit 1137 created 13 years 7 days ago. By meklort, Applies patch in issue #62 to trunk - Adds skip_partno support for multiboot bootloaders. | |
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1 | /* deflate.c -- compress data using the deflation algorithm␊ |
2 | * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler␊ |
3 | * For conditions of distribution and use, see copyright notice in zlib.h␊ |
4 | */␊ |
5 | ␊ |
6 | /*␊ |
7 | * ALGORITHM␊ |
8 | *␊ |
9 | * The "deflation" process depends on being able to identify portions␊ |
10 | * of the input text which are identical to earlier input (within a␊ |
11 | * sliding window trailing behind the input currently being processed).␊ |
12 | *␊ |
13 | * The most straightforward technique turns out to be the fastest for␊ |
14 | * most input files: try all possible matches and select the longest.␊ |
15 | * The key feature of this algorithm is that insertions into the string␊ |
16 | * dictionary are very simple and thus fast, and deletions are avoided␊ |
17 | * completely. Insertions are performed at each input character, whereas␊ |
18 | * string matches are performed only when the previous match ends. So it␊ |
19 | * is preferable to spend more time in matches to allow very fast string␊ |
20 | * insertions and avoid deletions. The matching algorithm for small␊ |
21 | * strings is inspired from that of Rabin & Karp. A brute force approach␊ |
22 | * is used to find longer strings when a small match has been found.␊ |
23 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze␊ |
24 | * (by Leonid Broukhis).␊ |
25 | * A previous version of this file used a more sophisticated algorithm␊ |
26 | * (by Fiala and Greene) which is guaranteed to run in linear amortized␊ |
27 | * time, but has a larger average cost, uses more memory and is patented.␊ |
28 | * However the F&G algorithm may be faster for some highly redundant␊ |
29 | * files if the parameter max_chain_length (described below) is too large.␊ |
30 | *␊ |
31 | * ACKNOWLEDGEMENTS␊ |
32 | *␊ |
33 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and␊ |
34 | * I found it in 'freeze' written by Leonid Broukhis.␊ |
35 | * Thanks to many people for bug reports and testing.␊ |
36 | *␊ |
37 | * REFERENCES␊ |
38 | *␊ |
39 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".␊ |
40 | * Available in http://www.ietf.org/rfc/rfc1951.txt␊ |
41 | *␊ |
42 | * A description of the Rabin and Karp algorithm is given in the book␊ |
43 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.␊ |
44 | *␊ |
45 | * Fiala,E.R., and Greene,D.H.␊ |
46 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595␊ |
47 | *␊ |
48 | */␊ |
49 | ␊ |
50 | /* @(#) $Id$ */␊ |
51 | ␊ |
52 | #include "deflate.h"␊ |
53 | ␊ |
54 | const char deflate_copyright[] =␊ |
55 | " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";␊ |
56 | /*␊ |
57 | If you use the zlib library in a product, an acknowledgment is welcome␊ |
58 | in the documentation of your product. If for some reason you cannot␊ |
59 | include such an acknowledgment, I would appreciate that you keep this␊ |
60 | copyright string in the executable of your product.␊ |
61 | */␊ |
62 | ␊ |
63 | /* ===========================================================================␊ |
64 | * Function prototypes.␊ |
65 | */␊ |
66 | typedef enum {␊ |
67 | need_more, /* block not completed, need more input or more output */␊ |
68 | block_done, /* block flush performed */␊ |
69 | finish_started, /* finish started, need only more output at next deflate */␊ |
70 | finish_done /* finish done, accept no more input or output */␊ |
71 | } block_state;␊ |
72 | ␊ |
73 | typedef block_state (*compress_func) OF((deflate_state *s, int flush));␊ |
74 | /* Compression function. Returns the block state after the call. */␊ |
75 | ␊ |
76 | local void fill_window OF((deflate_state *s));␊ |
77 | local block_state deflate_stored OF((deflate_state *s, int flush));␊ |
78 | local block_state deflate_fast OF((deflate_state *s, int flush));␊ |
79 | #ifndef FASTEST␊ |
80 | local block_state deflate_slow OF((deflate_state *s, int flush));␊ |
81 | #endif␊ |
82 | local block_state deflate_rle OF((deflate_state *s, int flush));␊ |
83 | local block_state deflate_huff OF((deflate_state *s, int flush));␊ |
84 | local void lm_init OF((deflate_state *s));␊ |
85 | local void putShortMSB OF((deflate_state *s, uInt b));␊ |
86 | local void flush_pending OF((z_streamp strm));␊ |
87 | local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));␊ |
88 | #ifdef ASMV␊ |
89 | void match_init OF((void)); /* asm code initialization */␊ |
90 | uInt longest_match OF((deflate_state *s, IPos cur_match));␊ |
91 | #else␊ |
92 | local uInt longest_match OF((deflate_state *s, IPos cur_match));␊ |
93 | #endif␊ |
94 | ␊ |
95 | #ifdef DEBUG␊ |
96 | local void check_match OF((deflate_state *s, IPos start, IPos match,␊ |
97 | int length));␊ |
98 | #endif␊ |
99 | ␊ |
100 | /* ===========================================================================␊ |
101 | * Local data␊ |
102 | */␊ |
103 | ␊ |
104 | #define NIL 0␊ |
105 | /* Tail of hash chains */␊ |
106 | ␊ |
107 | #ifndef TOO_FAR␊ |
108 | # define TOO_FAR 4096␊ |
109 | #endif␊ |
110 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */␊ |
111 | ␊ |
112 | /* Values for max_lazy_match, good_match and max_chain_length, depending on␊ |
113 | * the desired pack level (0..9). The values given below have been tuned to␊ |
114 | * exclude worst case performance for pathological files. Better values may be␊ |
115 | * found for specific files.␊ |
116 | */␊ |
117 | typedef struct config_s {␊ |
118 | ush good_length; /* reduce lazy search above this match length */␊ |
119 | ush max_lazy; /* do not perform lazy search above this match length */␊ |
120 | ush nice_length; /* quit search above this match length */␊ |
121 | ush max_chain;␊ |
122 | compress_func func;␊ |
123 | } config;␊ |
124 | ␊ |
125 | #ifdef FASTEST␊ |
126 | local const config configuration_table[2] = {␊ |
127 | /* good lazy nice chain */␊ |
128 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */␊ |
129 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */␊ |
130 | #else␊ |
131 | local const config configuration_table[10] = {␊ |
132 | /* good lazy nice chain */␊ |
133 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */␊ |
134 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */␊ |
135 | /* 2 */ {4, 5, 16, 8, deflate_fast},␊ |
136 | /* 3 */ {4, 6, 32, 32, deflate_fast},␊ |
137 | ␊ |
138 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */␊ |
139 | /* 5 */ {8, 16, 32, 32, deflate_slow},␊ |
140 | /* 6 */ {8, 16, 128, 128, deflate_slow},␊ |
141 | /* 7 */ {8, 32, 128, 256, deflate_slow},␊ |
142 | /* 8 */ {32, 128, 258, 1024, deflate_slow},␊ |
143 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */␊ |
144 | #endif␊ |
145 | ␊ |
146 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4␊ |
147 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different␊ |
148 | * meaning.␊ |
149 | */␊ |
150 | ␊ |
151 | #define EQUAL 0␊ |
152 | /* result of memcmp for equal strings */␊ |
153 | ␊ |
154 | #ifndef NO_DUMMY_DECL␊ |
155 | struct static_tree_desc_s {int dummy;}; /* for buggy compilers */␊ |
156 | #endif␊ |
157 | ␊ |
158 | /* ===========================================================================␊ |
159 | * Update a hash value with the given input byte␊ |
160 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive␊ |
161 | * input characters, so that a running hash key can be computed from the␊ |
162 | * previous key instead of complete recalculation each time.␊ |
163 | */␊ |
164 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)␊ |
165 | ␊ |
166 | ␊ |
167 | /* ===========================================================================␊ |
168 | * Insert string str in the dictionary and set match_head to the previous head␊ |
169 | * of the hash chain (the most recent string with same hash key). Return␊ |
170 | * the previous length of the hash chain.␊ |
171 | * If this file is compiled with -DFASTEST, the compression level is forced␊ |
172 | * to 1, and no hash chains are maintained.␊ |
173 | * IN assertion: all calls to to INSERT_STRING are made with consecutive␊ |
174 | * input characters and the first MIN_MATCH bytes of str are valid␊ |
175 | * (except for the last MIN_MATCH-1 bytes of the input file).␊ |
176 | */␊ |
177 | #ifdef FASTEST␊ |
178 | #define INSERT_STRING(s, str, match_head) \␊ |
179 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \␊ |
180 | match_head = s->head[s->ins_h], \␊ |
181 | s->head[s->ins_h] = (Pos)(str))␊ |
182 | #else␊ |
183 | #define INSERT_STRING(s, str, match_head) \␊ |
184 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \␊ |
185 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \␊ |
186 | s->head[s->ins_h] = (Pos)(str))␊ |
187 | #endif␊ |
188 | ␊ |
189 | /* ===========================================================================␊ |
190 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems).␊ |
191 | * prev[] will be initialized on the fly.␊ |
192 | */␊ |
193 | #define CLEAR_HASH(s) \␊ |
194 | s->head[s->hash_size-1] = NIL; \␊ |
195 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));␊ |
196 | ␊ |
197 | /* ========================================================================= */␊ |
198 | int ZEXPORT deflateInit_(strm, level, version, stream_size)␊ |
199 | z_streamp strm;␊ |
200 | int level;␊ |
201 | const char *version;␊ |
202 | int stream_size;␊ |
203 | {␊ |
204 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,␊ |
205 | Z_DEFAULT_STRATEGY, version, stream_size);␊ |
206 | /* To do: ignore strm->next_in if we use it as window */␊ |
207 | }␊ |
208 | ␊ |
209 | /* ========================================================================= */␊ |
210 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,␊ |
211 | version, stream_size)␊ |
212 | z_streamp strm;␊ |
213 | int level;␊ |
214 | int method;␊ |
215 | int windowBits;␊ |
216 | int memLevel;␊ |
217 | int strategy;␊ |
218 | const char *version;␊ |
219 | int stream_size;␊ |
220 | {␊ |
221 | deflate_state *s;␊ |
222 | int wrap = 1;␊ |
223 | static const char my_version[] = ZLIB_VERSION;␊ |
224 | ␊ |
225 | ushf *overlay;␊ |
226 | /* We overlay pending_buf and d_buf+l_buf. This works since the average␊ |
227 | * output size for (length,distance) codes is <= 24 bits.␊ |
228 | */␊ |
229 | ␊ |
230 | if (version == Z_NULL || version[0] != my_version[0] ||␊ |
231 | stream_size != sizeof(z_stream)) {␊ |
232 | return Z_VERSION_ERROR;␊ |
233 | }␊ |
234 | if (strm == Z_NULL) return Z_STREAM_ERROR;␊ |
235 | ␊ |
236 | strm->msg = Z_NULL;␊ |
237 | if (strm->zalloc == (alloc_func)0) {␊ |
238 | strm->zalloc = zcalloc;␊ |
239 | strm->opaque = (voidpf)0;␊ |
240 | }␊ |
241 | if (strm->zfree == (free_func)0) strm->zfree = zcfree;␊ |
242 | ␊ |
243 | #ifdef FASTEST␊ |
244 | if (level != 0) level = 1;␊ |
245 | #else␊ |
246 | if (level == Z_DEFAULT_COMPRESSION) level = 6;␊ |
247 | #endif␊ |
248 | ␊ |
249 | if (windowBits < 0) { /* suppress zlib wrapper */␊ |
250 | wrap = 0;␊ |
251 | windowBits = -windowBits;␊ |
252 | }␊ |
253 | #ifdef GZIP␊ |
254 | else if (windowBits > 15) {␊ |
255 | wrap = 2; /* write gzip wrapper instead */␊ |
256 | windowBits -= 16;␊ |
257 | }␊ |
258 | #endif␊ |
259 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||␊ |
260 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||␊ |
261 | strategy < 0 || strategy > Z_FIXED) {␊ |
262 | return Z_STREAM_ERROR;␊ |
263 | }␊ |
264 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */␊ |
265 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));␊ |
266 | if (s == Z_NULL) return Z_MEM_ERROR;␊ |
267 | strm->state = (struct internal_state FAR *)s;␊ |
268 | s->strm = strm;␊ |
269 | ␊ |
270 | s->wrap = wrap;␊ |
271 | s->gzhead = Z_NULL;␊ |
272 | s->w_bits = windowBits;␊ |
273 | s->w_size = 1 << s->w_bits;␊ |
274 | s->w_mask = s->w_size - 1;␊ |
275 | ␊ |
276 | s->hash_bits = memLevel + 7;␊ |
277 | s->hash_size = 1 << s->hash_bits;␊ |
278 | s->hash_mask = s->hash_size - 1;␊ |
279 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);␊ |
280 | ␊ |
281 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));␊ |
282 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));␊ |
283 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));␊ |
284 | ␊ |
285 | s->high_water = 0; /* nothing written to s->window yet */␊ |
286 | ␊ |
287 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */␊ |
288 | ␊ |
289 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);␊ |
290 | s->pending_buf = (uchf *) overlay;␊ |
291 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);␊ |
292 | ␊ |
293 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||␊ |
294 | s->pending_buf == Z_NULL) {␊ |
295 | s->status = FINISH_STATE;␊ |
296 | strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);␊ |
297 | deflateEnd (strm);␊ |
298 | return Z_MEM_ERROR;␊ |
299 | }␊ |
300 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush);␊ |
301 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;␊ |
302 | ␊ |
303 | s->level = level;␊ |
304 | s->strategy = strategy;␊ |
305 | s->method = (Byte)method;␊ |
306 | ␊ |
307 | return deflateReset(strm);␊ |
308 | }␊ |
309 | ␊ |
310 | /* ========================================================================= */␊ |
311 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)␊ |
312 | z_streamp strm;␊ |
313 | const Bytef *dictionary;␊ |
314 | uInt dictLength;␊ |
315 | {␊ |
316 | deflate_state *s;␊ |
317 | uInt length = dictLength;␊ |
318 | uInt n;␊ |
319 | IPos hash_head = 0;␊ |
320 | ␊ |
321 | if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||␊ |
322 | strm->state->wrap == 2 ||␊ |
323 | (strm->state->wrap == 1 && strm->state->status != INIT_STATE))␊ |
324 | return Z_STREAM_ERROR;␊ |
325 | ␊ |
326 | s = strm->state;␊ |
327 | if (s->wrap)␊ |
328 | strm->adler = adler32(strm->adler, dictionary, dictLength);␊ |
329 | ␊ |
330 | if (length < MIN_MATCH) return Z_OK;␊ |
331 | if (length > s->w_size) {␊ |
332 | length = s->w_size;␊ |
333 | dictionary += dictLength - length; /* use the tail of the dictionary */␊ |
334 | }␊ |
335 | zmemcpy(s->window, dictionary, length);␊ |
336 | s->strstart = length;␊ |
337 | s->block_start = (long)length;␊ |
338 | ␊ |
339 | /* Insert all strings in the hash table (except for the last two bytes).␊ |
340 | * s->lookahead stays null, so s->ins_h will be recomputed at the next␊ |
341 | * call of fill_window.␊ |
342 | */␊ |
343 | s->ins_h = s->window[0];␊ |
344 | UPDATE_HASH(s, s->ins_h, s->window[1]);␊ |
345 | for (n = 0; n <= length - MIN_MATCH; n++) {␊ |
346 | INSERT_STRING(s, n, hash_head);␊ |
347 | }␊ |
348 | if (hash_head) hash_head = 0; /* to make compiler happy */␊ |
349 | return Z_OK;␊ |
350 | }␊ |
351 | ␊ |
352 | /* ========================================================================= */␊ |
353 | int ZEXPORT deflateReset (strm)␊ |
354 | z_streamp strm;␊ |
355 | {␊ |
356 | deflate_state *s;␊ |
357 | ␊ |
358 | if (strm == Z_NULL || strm->state == Z_NULL ||␊ |
359 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {␊ |
360 | return Z_STREAM_ERROR;␊ |
361 | }␊ |
362 | ␊ |
363 | strm->total_in = strm->total_out = 0;␊ |
364 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */␊ |
365 | strm->data_type = Z_UNKNOWN;␊ |
366 | ␊ |
367 | s = (deflate_state *)strm->state;␊ |
368 | s->pending = 0;␊ |
369 | s->pending_out = s->pending_buf;␊ |
370 | ␊ |
371 | if (s->wrap < 0) {␊ |
372 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */␊ |
373 | }␊ |
374 | s->status = s->wrap ? INIT_STATE : BUSY_STATE;␊ |
375 | strm->adler =␊ |
376 | #ifdef GZIP␊ |
377 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) :␊ |
378 | #endif␊ |
379 | adler32(0L, Z_NULL, 0);␊ |
380 | s->last_flush = Z_NO_FLUSH;␊ |
381 | ␊ |
382 | _tr_init(s);␊ |
383 | lm_init(s);␊ |
384 | ␊ |
385 | return Z_OK;␊ |
386 | }␊ |
387 | ␊ |
388 | /* ========================================================================= */␊ |
389 | int ZEXPORT deflateSetHeader (strm, head)␊ |
390 | z_streamp strm;␊ |
391 | gz_headerp head;␊ |
392 | {␊ |
393 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
394 | if (strm->state->wrap != 2) return Z_STREAM_ERROR;␊ |
395 | strm->state->gzhead = head;␊ |
396 | return Z_OK;␊ |
397 | }␊ |
398 | ␊ |
399 | /* ========================================================================= */␊ |
400 | int ZEXPORT deflatePrime (strm, bits, value)␊ |
401 | z_streamp strm;␊ |
402 | int bits;␊ |
403 | int value;␊ |
404 | {␊ |
405 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
406 | strm->state->bi_valid = bits;␊ |
407 | strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));␊ |
408 | return Z_OK;␊ |
409 | }␊ |
410 | ␊ |
411 | /* ========================================================================= */␊ |
412 | int ZEXPORT deflateParams(strm, level, strategy)␊ |
413 | z_streamp strm;␊ |
414 | int level;␊ |
415 | int strategy;␊ |
416 | {␊ |
417 | deflate_state *s;␊ |
418 | compress_func func;␊ |
419 | int err = Z_OK;␊ |
420 | ␊ |
421 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
422 | s = strm->state;␊ |
423 | ␊ |
424 | #ifdef FASTEST␊ |
425 | if (level != 0) level = 1;␊ |
426 | #else␊ |
427 | if (level == Z_DEFAULT_COMPRESSION) level = 6;␊ |
428 | #endif␊ |
429 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {␊ |
430 | return Z_STREAM_ERROR;␊ |
431 | }␊ |
432 | func = configuration_table[s->level].func;␊ |
433 | ␊ |
434 | if ((strategy != s->strategy || func != configuration_table[level].func) &&␊ |
435 | strm->total_in != 0) {␊ |
436 | /* Flush the last buffer: */␊ |
437 | err = deflate(strm, Z_BLOCK);␊ |
438 | }␊ |
439 | if (s->level != level) {␊ |
440 | s->level = level;␊ |
441 | s->max_lazy_match = configuration_table[level].max_lazy;␊ |
442 | s->good_match = configuration_table[level].good_length;␊ |
443 | s->nice_match = configuration_table[level].nice_length;␊ |
444 | s->max_chain_length = configuration_table[level].max_chain;␊ |
445 | }␊ |
446 | s->strategy = strategy;␊ |
447 | return err;␊ |
448 | }␊ |
449 | ␊ |
450 | /* ========================================================================= */␊ |
451 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)␊ |
452 | z_streamp strm;␊ |
453 | int good_length;␊ |
454 | int max_lazy;␊ |
455 | int nice_length;␊ |
456 | int max_chain;␊ |
457 | {␊ |
458 | deflate_state *s;␊ |
459 | ␊ |
460 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
461 | s = strm->state;␊ |
462 | s->good_match = good_length;␊ |
463 | s->max_lazy_match = max_lazy;␊ |
464 | s->nice_match = nice_length;␊ |
465 | s->max_chain_length = max_chain;␊ |
466 | return Z_OK;␊ |
467 | }␊ |
468 | ␊ |
469 | /* =========================================================================␊ |
470 | * For the default windowBits of 15 and memLevel of 8, this function returns␊ |
471 | * a close to exact, as well as small, upper bound on the compressed size.␊ |
472 | * They are coded as constants here for a reason--if the #define's are␊ |
473 | * changed, then this function needs to be changed as well. The return␊ |
474 | * value for 15 and 8 only works for those exact settings.␊ |
475 | *␊ |
476 | * For any setting other than those defaults for windowBits and memLevel,␊ |
477 | * the value returned is a conservative worst case for the maximum expansion␊ |
478 | * resulting from using fixed blocks instead of stored blocks, which deflate␊ |
479 | * can emit on compressed data for some combinations of the parameters.␊ |
480 | *␊ |
481 | * This function could be more sophisticated to provide closer upper bounds for␊ |
482 | * every combination of windowBits and memLevel. But even the conservative␊ |
483 | * upper bound of about 14% expansion does not seem onerous for output buffer␊ |
484 | * allocation.␊ |
485 | */␊ |
486 | uLong ZEXPORT deflateBound(strm, sourceLen)␊ |
487 | z_streamp strm;␊ |
488 | uLong sourceLen;␊ |
489 | {␊ |
490 | deflate_state *s;␊ |
491 | uLong complen, wraplen;␊ |
492 | Bytef *str;␊ |
493 | ␊ |
494 | /* conservative upper bound for compressed data */␊ |
495 | complen = sourceLen +␊ |
496 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;␊ |
497 | ␊ |
498 | /* if can't get parameters, return conservative bound plus zlib wrapper */␊ |
499 | if (strm == Z_NULL || strm->state == Z_NULL)␊ |
500 | return complen + 6;␊ |
501 | ␊ |
502 | /* compute wrapper length */␊ |
503 | s = strm->state;␊ |
504 | switch (s->wrap) {␊ |
505 | case 0: /* raw deflate */␊ |
506 | wraplen = 0;␊ |
507 | break;␊ |
508 | case 1: /* zlib wrapper */␊ |
509 | wraplen = 6 + (s->strstart ? 4 : 0);␊ |
510 | break;␊ |
511 | case 2: /* gzip wrapper */␊ |
512 | wraplen = 18;␊ |
513 | if (s->gzhead != Z_NULL) { /* user-supplied gzip header */␊ |
514 | if (s->gzhead->extra != Z_NULL)␊ |
515 | wraplen += 2 + s->gzhead->extra_len;␊ |
516 | str = s->gzhead->name;␊ |
517 | if (str != Z_NULL)␊ |
518 | do {␊ |
519 | wraplen++;␊ |
520 | } while (*str++);␊ |
521 | str = s->gzhead->comment;␊ |
522 | if (str != Z_NULL)␊ |
523 | do {␊ |
524 | wraplen++;␊ |
525 | } while (*str++);␊ |
526 | if (s->gzhead->hcrc)␊ |
527 | wraplen += 2;␊ |
528 | }␊ |
529 | break;␊ |
530 | default: /* for compiler happiness */␊ |
531 | wraplen = 6;␊ |
532 | }␊ |
533 | ␊ |
534 | /* if not default parameters, return conservative bound */␊ |
535 | if (s->w_bits != 15 || s->hash_bits != 8 + 7)␊ |
536 | return complen + wraplen;␊ |
537 | ␊ |
538 | /* default settings: return tight bound for that case */␊ |
539 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +␊ |
540 | (sourceLen >> 25) + 13 - 6 + wraplen;␊ |
541 | }␊ |
542 | ␊ |
543 | /* =========================================================================␊ |
544 | * Put a short in the pending buffer. The 16-bit value is put in MSB order.␊ |
545 | * IN assertion: the stream state is correct and there is enough room in␊ |
546 | * pending_buf.␊ |
547 | */␊ |
548 | local void putShortMSB (s, b)␊ |
549 | deflate_state *s;␊ |
550 | uInt b;␊ |
551 | {␊ |
552 | put_byte(s, (Byte)(b >> 8));␊ |
553 | put_byte(s, (Byte)(b & 0xff));␊ |
554 | }␊ |
555 | ␊ |
556 | /* =========================================================================␊ |
557 | * Flush as much pending output as possible. All deflate() output goes␊ |
558 | * through this function so some applications may wish to modify it␊ |
559 | * to avoid allocating a large strm->next_out buffer and copying into it.␊ |
560 | * (See also read_buf()).␊ |
561 | */␊ |
562 | local void flush_pending(strm)␊ |
563 | z_streamp strm;␊ |
564 | {␊ |
565 | unsigned len = strm->state->pending;␊ |
566 | ␊ |
567 | if (len > strm->avail_out) len = strm->avail_out;␊ |
568 | if (len == 0) return;␊ |
569 | ␊ |
570 | zmemcpy(strm->next_out, strm->state->pending_out, len);␊ |
571 | strm->next_out += len;␊ |
572 | strm->state->pending_out += len;␊ |
573 | strm->total_out += len;␊ |
574 | strm->avail_out -= len;␊ |
575 | strm->state->pending -= len;␊ |
576 | if (strm->state->pending == 0) {␊ |
577 | strm->state->pending_out = strm->state->pending_buf;␊ |
578 | }␊ |
579 | }␊ |
580 | ␊ |
581 | /* ========================================================================= */␊ |
582 | int ZEXPORT deflate (strm, flush)␊ |
583 | z_streamp strm;␊ |
584 | int flush;␊ |
585 | {␊ |
586 | int old_flush; /* value of flush param for previous deflate call */␊ |
587 | deflate_state *s;␊ |
588 | ␊ |
589 | if (strm == Z_NULL || strm->state == Z_NULL ||␊ |
590 | flush > Z_BLOCK || flush < 0) {␊ |
591 | return Z_STREAM_ERROR;␊ |
592 | }␊ |
593 | s = strm->state;␊ |
594 | ␊ |
595 | if (strm->next_out == Z_NULL ||␊ |
596 | (strm->next_in == Z_NULL && strm->avail_in != 0) ||␊ |
597 | (s->status == FINISH_STATE && flush != Z_FINISH)) {␊ |
598 | ERR_RETURN(strm, Z_STREAM_ERROR);␊ |
599 | }␊ |
600 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);␊ |
601 | ␊ |
602 | s->strm = strm; /* just in case */␊ |
603 | old_flush = s->last_flush;␊ |
604 | s->last_flush = flush;␊ |
605 | ␊ |
606 | /* Write the header */␊ |
607 | if (s->status == INIT_STATE) {␊ |
608 | #ifdef GZIP␊ |
609 | if (s->wrap == 2) {␊ |
610 | strm->adler = crc32(0L, Z_NULL, 0);␊ |
611 | put_byte(s, 31);␊ |
612 | put_byte(s, 139);␊ |
613 | put_byte(s, 8);␊ |
614 | if (s->gzhead == Z_NULL) {␊ |
615 | put_byte(s, 0);␊ |
616 | put_byte(s, 0);␊ |
617 | put_byte(s, 0);␊ |
618 | put_byte(s, 0);␊ |
619 | put_byte(s, 0);␊ |
620 | put_byte(s, s->level == 9 ? 2 :␊ |
621 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?␊ |
622 | 4 : 0));␊ |
623 | put_byte(s, OS_CODE);␊ |
624 | s->status = BUSY_STATE;␊ |
625 | }␊ |
626 | else {␊ |
627 | put_byte(s, (s->gzhead->text ? 1 : 0) +␊ |
628 | (s->gzhead->hcrc ? 2 : 0) +␊ |
629 | (s->gzhead->extra == Z_NULL ? 0 : 4) +␊ |
630 | (s->gzhead->name == Z_NULL ? 0 : 8) +␊ |
631 | (s->gzhead->comment == Z_NULL ? 0 : 16)␊ |
632 | );␊ |
633 | put_byte(s, (Byte)(s->gzhead->time & 0xff));␊ |
634 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));␊ |
635 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));␊ |
636 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));␊ |
637 | put_byte(s, s->level == 9 ? 2 :␊ |
638 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?␊ |
639 | 4 : 0));␊ |
640 | put_byte(s, s->gzhead->os & 0xff);␊ |
641 | if (s->gzhead->extra != Z_NULL) {␊ |
642 | put_byte(s, s->gzhead->extra_len & 0xff);␊ |
643 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);␊ |
644 | }␊ |
645 | if (s->gzhead->hcrc)␊ |
646 | strm->adler = crc32(strm->adler, s->pending_buf,␊ |
647 | s->pending);␊ |
648 | s->gzindex = 0;␊ |
649 | s->status = EXTRA_STATE;␊ |
650 | }␊ |
651 | }␊ |
652 | else␊ |
653 | #endif␊ |
654 | {␊ |
655 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;␊ |
656 | uInt level_flags;␊ |
657 | ␊ |
658 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)␊ |
659 | level_flags = 0;␊ |
660 | else if (s->level < 6)␊ |
661 | level_flags = 1;␊ |
662 | else if (s->level == 6)␊ |
663 | level_flags = 2;␊ |
664 | else␊ |
665 | level_flags = 3;␊ |
666 | header |= (level_flags << 6);␊ |
667 | if (s->strstart != 0) header |= PRESET_DICT;␊ |
668 | header += 31 - (header % 31);␊ |
669 | ␊ |
670 | s->status = BUSY_STATE;␊ |
671 | putShortMSB(s, header);␊ |
672 | ␊ |
673 | /* Save the adler32 of the preset dictionary: */␊ |
674 | if (s->strstart != 0) {␊ |
675 | putShortMSB(s, (uInt)(strm->adler >> 16));␊ |
676 | putShortMSB(s, (uInt)(strm->adler & 0xffff));␊ |
677 | }␊ |
678 | strm->adler = adler32(0L, Z_NULL, 0);␊ |
679 | }␊ |
680 | }␊ |
681 | #ifdef GZIP␊ |
682 | if (s->status == EXTRA_STATE) {␊ |
683 | if (s->gzhead->extra != Z_NULL) {␊ |
684 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
685 | ␊ |
686 | while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {␊ |
687 | if (s->pending == s->pending_buf_size) {␊ |
688 | if (s->gzhead->hcrc && s->pending > beg)␊ |
689 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
690 | s->pending - beg);␊ |
691 | flush_pending(strm);␊ |
692 | beg = s->pending;␊ |
693 | if (s->pending == s->pending_buf_size)␊ |
694 | break;␊ |
695 | }␊ |
696 | put_byte(s, s->gzhead->extra[s->gzindex]);␊ |
697 | s->gzindex++;␊ |
698 | }␊ |
699 | if (s->gzhead->hcrc && s->pending > beg)␊ |
700 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
701 | s->pending - beg);␊ |
702 | if (s->gzindex == s->gzhead->extra_len) {␊ |
703 | s->gzindex = 0;␊ |
704 | s->status = NAME_STATE;␊ |
705 | }␊ |
706 | }␊ |
707 | else␊ |
708 | s->status = NAME_STATE;␊ |
709 | }␊ |
710 | if (s->status == NAME_STATE) {␊ |
711 | if (s->gzhead->name != Z_NULL) {␊ |
712 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
713 | int val;␊ |
714 | ␊ |
715 | do {␊ |
716 | if (s->pending == s->pending_buf_size) {␊ |
717 | if (s->gzhead->hcrc && s->pending > beg)␊ |
718 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
719 | s->pending - beg);␊ |
720 | flush_pending(strm);␊ |
721 | beg = s->pending;␊ |
722 | if (s->pending == s->pending_buf_size) {␊ |
723 | val = 1;␊ |
724 | break;␊ |
725 | }␊ |
726 | }␊ |
727 | val = s->gzhead->name[s->gzindex++];␊ |
728 | put_byte(s, val);␊ |
729 | } while (val != 0);␊ |
730 | if (s->gzhead->hcrc && s->pending > beg)␊ |
731 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
732 | s->pending - beg);␊ |
733 | if (val == 0) {␊ |
734 | s->gzindex = 0;␊ |
735 | s->status = COMMENT_STATE;␊ |
736 | }␊ |
737 | }␊ |
738 | else␊ |
739 | s->status = COMMENT_STATE;␊ |
740 | }␊ |
741 | if (s->status == COMMENT_STATE) {␊ |
742 | if (s->gzhead->comment != Z_NULL) {␊ |
743 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
744 | int val;␊ |
745 | ␊ |
746 | do {␊ |
747 | if (s->pending == s->pending_buf_size) {␊ |
748 | if (s->gzhead->hcrc && s->pending > beg)␊ |
749 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
750 | s->pending - beg);␊ |
751 | flush_pending(strm);␊ |
752 | beg = s->pending;␊ |
753 | if (s->pending == s->pending_buf_size) {␊ |
754 | val = 1;␊ |
755 | break;␊ |
756 | }␊ |
757 | }␊ |
758 | val = s->gzhead->comment[s->gzindex++];␊ |
759 | put_byte(s, val);␊ |
760 | } while (val != 0);␊ |
761 | if (s->gzhead->hcrc && s->pending > beg)␊ |
762 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
763 | s->pending - beg);␊ |
764 | if (val == 0)␊ |
765 | s->status = HCRC_STATE;␊ |
766 | }␊ |
767 | else␊ |
768 | s->status = HCRC_STATE;␊ |
769 | }␊ |
770 | if (s->status == HCRC_STATE) {␊ |
771 | if (s->gzhead->hcrc) {␊ |
772 | if (s->pending + 2 > s->pending_buf_size)␊ |
773 | flush_pending(strm);␊ |
774 | if (s->pending + 2 <= s->pending_buf_size) {␊ |
775 | put_byte(s, (Byte)(strm->adler & 0xff));␊ |
776 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));␊ |
777 | strm->adler = crc32(0L, Z_NULL, 0);␊ |
778 | s->status = BUSY_STATE;␊ |
779 | }␊ |
780 | }␊ |
781 | else␊ |
782 | s->status = BUSY_STATE;␊ |
783 | }␊ |
784 | #endif␊ |
785 | ␊ |
786 | /* Flush as much pending output as possible */␊ |
787 | if (s->pending != 0) {␊ |
788 | flush_pending(strm);␊ |
789 | if (strm->avail_out == 0) {␊ |
790 | /* Since avail_out is 0, deflate will be called again with␊ |
791 | * more output space, but possibly with both pending and␊ |
792 | * avail_in equal to zero. There won't be anything to do,␊ |
793 | * but this is not an error situation so make sure we␊ |
794 | * return OK instead of BUF_ERROR at next call of deflate:␊ |
795 | */␊ |
796 | s->last_flush = -1;␊ |
797 | return Z_OK;␊ |
798 | }␊ |
799 | ␊ |
800 | /* Make sure there is something to do and avoid duplicate consecutive␊ |
801 | * flushes. For repeated and useless calls with Z_FINISH, we keep␊ |
802 | * returning Z_STREAM_END instead of Z_BUF_ERROR.␊ |
803 | */␊ |
804 | } else if (strm->avail_in == 0 && flush <= old_flush &&␊ |
805 | flush != Z_FINISH) {␊ |
806 | ERR_RETURN(strm, Z_BUF_ERROR);␊ |
807 | }␊ |
808 | ␊ |
809 | /* User must not provide more input after the first FINISH: */␊ |
810 | if (s->status == FINISH_STATE && strm->avail_in != 0) {␊ |
811 | ERR_RETURN(strm, Z_BUF_ERROR);␊ |
812 | }␊ |
813 | ␊ |
814 | /* Start a new block or continue the current one.␊ |
815 | */␊ |
816 | if (strm->avail_in != 0 || s->lookahead != 0 ||␊ |
817 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {␊ |
818 | block_state bstate;␊ |
819 | ␊ |
820 | bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :␊ |
821 | (s->strategy == Z_RLE ? deflate_rle(s, flush) :␊ |
822 | (*(configuration_table[s->level].func))(s, flush));␊ |
823 | ␊ |
824 | if (bstate == finish_started || bstate == finish_done) {␊ |
825 | s->status = FINISH_STATE;␊ |
826 | }␊ |
827 | if (bstate == need_more || bstate == finish_started) {␊ |
828 | if (strm->avail_out == 0) {␊ |
829 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */␊ |
830 | }␊ |
831 | return Z_OK;␊ |
832 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call␊ |
833 | * of deflate should use the same flush parameter to make sure␊ |
834 | * that the flush is complete. So we don't have to output an␊ |
835 | * empty block here, this will be done at next call. This also␊ |
836 | * ensures that for a very small output buffer, we emit at most␊ |
837 | * one empty block.␊ |
838 | */␊ |
839 | }␊ |
840 | if (bstate == block_done) {␊ |
841 | if (flush == Z_PARTIAL_FLUSH) {␊ |
842 | _tr_align(s);␊ |
843 | } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */␊ |
844 | _tr_stored_block(s, (char*)0, 0L, 0);␊ |
845 | /* For a full flush, this empty block will be recognized␊ |
846 | * as a special marker by inflate_sync().␊ |
847 | */␊ |
848 | if (flush == Z_FULL_FLUSH) {␊ |
849 | CLEAR_HASH(s); /* forget history */␊ |
850 | if (s->lookahead == 0) {␊ |
851 | s->strstart = 0;␊ |
852 | s->block_start = 0L;␊ |
853 | }␊ |
854 | }␊ |
855 | }␊ |
856 | flush_pending(strm);␊ |
857 | if (strm->avail_out == 0) {␊ |
858 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */␊ |
859 | return Z_OK;␊ |
860 | }␊ |
861 | }␊ |
862 | }␊ |
863 | Assert(strm->avail_out > 0, "bug2");␊ |
864 | ␊ |
865 | if (flush != Z_FINISH) return Z_OK;␊ |
866 | if (s->wrap <= 0) return Z_STREAM_END;␊ |
867 | ␊ |
868 | /* Write the trailer */␊ |
869 | #ifdef GZIP␊ |
870 | if (s->wrap == 2) {␊ |
871 | put_byte(s, (Byte)(strm->adler & 0xff));␊ |
872 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));␊ |
873 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff));␊ |
874 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff));␊ |
875 | put_byte(s, (Byte)(strm->total_in & 0xff));␊ |
876 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));␊ |
877 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));␊ |
878 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));␊ |
879 | }␊ |
880 | else␊ |
881 | #endif␊ |
882 | {␊ |
883 | putShortMSB(s, (uInt)(strm->adler >> 16));␊ |
884 | putShortMSB(s, (uInt)(strm->adler & 0xffff));␊ |
885 | }␊ |
886 | flush_pending(strm);␊ |
887 | /* If avail_out is zero, the application will call deflate again␊ |
888 | * to flush the rest.␊ |
889 | */␊ |
890 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */␊ |
891 | return s->pending != 0 ? Z_OK : Z_STREAM_END;␊ |
892 | }␊ |
893 | ␊ |
894 | /* ========================================================================= */␊ |
895 | int ZEXPORT deflateEnd (strm)␊ |
896 | z_streamp strm;␊ |
897 | {␊ |
898 | int status;␊ |
899 | ␊ |
900 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
901 | ␊ |
902 | status = strm->state->status;␊ |
903 | if (status != INIT_STATE &&␊ |
904 | status != EXTRA_STATE &&␊ |
905 | status != NAME_STATE &&␊ |
906 | status != COMMENT_STATE &&␊ |
907 | status != HCRC_STATE &&␊ |
908 | status != BUSY_STATE &&␊ |
909 | status != FINISH_STATE) {␊ |
910 | return Z_STREAM_ERROR;␊ |
911 | }␊ |
912 | ␊ |
913 | /* Deallocate in reverse order of allocations: */␊ |
914 | TRY_FREE(strm, strm->state->pending_buf);␊ |
915 | TRY_FREE(strm, strm->state->head);␊ |
916 | TRY_FREE(strm, strm->state->prev);␊ |
917 | TRY_FREE(strm, strm->state->window);␊ |
918 | ␊ |
919 | ZFREE(strm, strm->state);␊ |
920 | strm->state = Z_NULL;␊ |
921 | ␊ |
922 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;␊ |
923 | }␊ |
924 | ␊ |
925 | /* =========================================================================␊ |
926 | * Copy the source state to the destination state.␊ |
927 | * To simplify the source, this is not supported for 16-bit MSDOS (which␊ |
928 | * doesn't have enough memory anyway to duplicate compression states).␊ |
929 | */␊ |
930 | int ZEXPORT deflateCopy (dest, source)␊ |
931 | z_streamp dest;␊ |
932 | z_streamp source;␊ |
933 | {␊ |
934 | #ifdef MAXSEG_64K␊ |
935 | return Z_STREAM_ERROR;␊ |
936 | #else␊ |
937 | deflate_state *ds;␊ |
938 | deflate_state *ss;␊ |
939 | ushf *overlay;␊ |
940 | ␊ |
941 | ␊ |
942 | if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {␊ |
943 | return Z_STREAM_ERROR;␊ |
944 | }␊ |
945 | ␊ |
946 | ss = source->state;␊ |
947 | ␊ |
948 | zmemcpy(dest, source, sizeof(z_stream));␊ |
949 | ␊ |
950 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));␊ |
951 | if (ds == Z_NULL) return Z_MEM_ERROR;␊ |
952 | dest->state = (struct internal_state FAR *) ds;␊ |
953 | zmemcpy(ds, ss, sizeof(deflate_state));␊ |
954 | ds->strm = dest;␊ |
955 | ␊ |
956 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));␊ |
957 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));␊ |
958 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));␊ |
959 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);␊ |
960 | ds->pending_buf = (uchf *) overlay;␊ |
961 | ␊ |
962 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||␊ |
963 | ds->pending_buf == Z_NULL) {␊ |
964 | deflateEnd (dest);␊ |
965 | return Z_MEM_ERROR;␊ |
966 | }␊ |
967 | /* following zmemcpy do not work for 16-bit MSDOS */␊ |
968 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));␊ |
969 | zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));␊ |
970 | zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));␊ |
971 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);␊ |
972 | ␊ |
973 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);␊ |
974 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);␊ |
975 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;␊ |
976 | ␊ |
977 | ds->l_desc.dyn_tree = ds->dyn_ltree;␊ |
978 | ds->d_desc.dyn_tree = ds->dyn_dtree;␊ |
979 | ds->bl_desc.dyn_tree = ds->bl_tree;␊ |
980 | ␊ |
981 | return Z_OK;␊ |
982 | #endif /* MAXSEG_64K */␊ |
983 | }␊ |
984 | ␊ |
985 | /* ===========================================================================␊ |
986 | * Read a new buffer from the current input stream, update the adler32␊ |
987 | * and total number of bytes read. All deflate() input goes through␊ |
988 | * this function so some applications may wish to modify it to avoid␊ |
989 | * allocating a large strm->next_in buffer and copying from it.␊ |
990 | * (See also flush_pending()).␊ |
991 | */␊ |
992 | local int read_buf(strm, buf, size)␊ |
993 | z_streamp strm;␊ |
994 | Bytef *buf;␊ |
995 | unsigned size;␊ |
996 | {␊ |
997 | unsigned len = strm->avail_in;␊ |
998 | ␊ |
999 | if (len > size) len = size;␊ |
1000 | if (len == 0) return 0;␊ |
1001 | ␊ |
1002 | strm->avail_in -= len;␊ |
1003 | ␊ |
1004 | if (strm->state->wrap == 1) {␊ |
1005 | strm->adler = adler32(strm->adler, strm->next_in, len);␊ |
1006 | }␊ |
1007 | #ifdef GZIP␊ |
1008 | else if (strm->state->wrap == 2) {␊ |
1009 | strm->adler = crc32(strm->adler, strm->next_in, len);␊ |
1010 | }␊ |
1011 | #endif␊ |
1012 | zmemcpy(buf, strm->next_in, len);␊ |
1013 | strm->next_in += len;␊ |
1014 | strm->total_in += len;␊ |
1015 | ␊ |
1016 | return (int)len;␊ |
1017 | }␊ |
1018 | ␊ |
1019 | /* ===========================================================================␊ |
1020 | * Initialize the "longest match" routines for a new zlib stream␊ |
1021 | */␊ |
1022 | local void lm_init (s)␊ |
1023 | deflate_state *s;␊ |
1024 | {␊ |
1025 | s->window_size = (ulg)2L*s->w_size;␊ |
1026 | ␊ |
1027 | CLEAR_HASH(s);␊ |
1028 | ␊ |
1029 | /* Set the default configuration parameters:␊ |
1030 | */␊ |
1031 | s->max_lazy_match = configuration_table[s->level].max_lazy;␊ |
1032 | s->good_match = configuration_table[s->level].good_length;␊ |
1033 | s->nice_match = configuration_table[s->level].nice_length;␊ |
1034 | s->max_chain_length = configuration_table[s->level].max_chain;␊ |
1035 | ␊ |
1036 | s->strstart = 0;␊ |
1037 | s->block_start = 0L;␊ |
1038 | s->lookahead = 0;␊ |
1039 | s->match_length = s->prev_length = MIN_MATCH-1;␊ |
1040 | s->match_available = 0;␊ |
1041 | s->ins_h = 0;␊ |
1042 | #ifndef FASTEST␊ |
1043 | #ifdef ASMV␊ |
1044 | match_init(); /* initialize the asm code */␊ |
1045 | #endif␊ |
1046 | #endif␊ |
1047 | }␊ |
1048 | ␊ |
1049 | #ifndef FASTEST␊ |
1050 | /* ===========================================================================␊ |
1051 | * Set match_start to the longest match starting at the given string and␊ |
1052 | * return its length. Matches shorter or equal to prev_length are discarded,␊ |
1053 | * in which case the result is equal to prev_length and match_start is␊ |
1054 | * garbage.␊ |
1055 | * IN assertions: cur_match is the head of the hash chain for the current␊ |
1056 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1␊ |
1057 | * OUT assertion: the match length is not greater than s->lookahead.␊ |
1058 | */␊ |
1059 | #ifndef ASMV␊ |
1060 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or␊ |
1061 | * match.S. The code will be functionally equivalent.␊ |
1062 | */␊ |
1063 | local uInt longest_match(s, cur_match)␊ |
1064 | deflate_state *s;␊ |
1065 | IPos cur_match; /* current match */␊ |
1066 | {␊ |
1067 | unsigned chain_length = s->max_chain_length;/* max hash chain length */␊ |
1068 | register Bytef *scan = s->window + s->strstart; /* current string */␊ |
1069 | register Bytef *match; /* matched string */␊ |
1070 | register int len; /* length of current match */␊ |
1071 | int best_len = s->prev_length; /* best match length so far */␊ |
1072 | int nice_match = s->nice_match; /* stop if match long enough */␊ |
1073 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ?␊ |
1074 | s->strstart - (IPos)MAX_DIST(s) : NIL;␊ |
1075 | /* Stop when cur_match becomes <= limit. To simplify the code,␊ |
1076 | * we prevent matches with the string of window index 0.␊ |
1077 | */␊ |
1078 | Posf *prev = s->prev;␊ |
1079 | uInt wmask = s->w_mask;␊ |
1080 | ␊ |
1081 | #ifdef UNALIGNED_OK␊ |
1082 | /* Compare two bytes at a time. Note: this is not always beneficial.␊ |
1083 | * Try with and without -DUNALIGNED_OK to check.␊ |
1084 | */␊ |
1085 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;␊ |
1086 | register ush scan_start = *(ushf*)scan;␊ |
1087 | register ush scan_end = *(ushf*)(scan+best_len-1);␊ |
1088 | #else␊ |
1089 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;␊ |
1090 | register Byte scan_end1 = scan[best_len-1];␊ |
1091 | register Byte scan_end = scan[best_len];␊ |
1092 | #endif␊ |
1093 | ␊ |
1094 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.␊ |
1095 | * It is easy to get rid of this optimization if necessary.␊ |
1096 | */␊ |
1097 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");␊ |
1098 | ␊ |
1099 | /* Do not waste too much time if we already have a good match: */␊ |
1100 | if (s->prev_length >= s->good_match) {␊ |
1101 | chain_length >>= 2;␊ |
1102 | }␊ |
1103 | /* Do not look for matches beyond the end of the input. This is necessary␊ |
1104 | * to make deflate deterministic.␊ |
1105 | */␊ |
1106 | if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;␊ |
1107 | ␊ |
1108 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");␊ |
1109 | ␊ |
1110 | do {␊ |
1111 | Assert(cur_match < s->strstart, "no future");␊ |
1112 | match = s->window + cur_match;␊ |
1113 | ␊ |
1114 | /* Skip to next match if the match length cannot increase␊ |
1115 | * or if the match length is less than 2. Note that the checks below␊ |
1116 | * for insufficient lookahead only occur occasionally for performance␊ |
1117 | * reasons. Therefore uninitialized memory will be accessed, and␊ |
1118 | * conditional jumps will be made that depend on those values.␊ |
1119 | * However the length of the match is limited to the lookahead, so␊ |
1120 | * the output of deflate is not affected by the uninitialized values.␊ |
1121 | */␊ |
1122 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)␊ |
1123 | /* This code assumes sizeof(unsigned short) == 2. Do not use␊ |
1124 | * UNALIGNED_OK if your compiler uses a different size.␊ |
1125 | */␊ |
1126 | if (*(ushf*)(match+best_len-1) != scan_end ||␊ |
1127 | *(ushf*)match != scan_start) continue;␊ |
1128 | ␊ |
1129 | /* It is not necessary to compare scan[2] and match[2] since they are␊ |
1130 | * always equal when the other bytes match, given that the hash keys␊ |
1131 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at␊ |
1132 | * strstart+3, +5, ... up to strstart+257. We check for insufficient␊ |
1133 | * lookahead only every 4th comparison; the 128th check will be made␊ |
1134 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is␊ |
1135 | * necessary to put more guard bytes at the end of the window, or␊ |
1136 | * to check more often for insufficient lookahead.␊ |
1137 | */␊ |
1138 | Assert(scan[2] == match[2], "scan[2]?");␊ |
1139 | scan++, match++;␊ |
1140 | do {␊ |
1141 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
1142 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
1143 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
1144 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
1145 | scan < strend);␊ |
1146 | /* The funny "do {}" generates better code on most compilers */␊ |
1147 | ␊ |
1148 | /* Here, scan <= window+strstart+257 */␊ |
1149 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
1150 | if (*scan == *match) scan++;␊ |
1151 | ␊ |
1152 | len = (MAX_MATCH - 1) - (int)(strend-scan);␊ |
1153 | scan = strend - (MAX_MATCH-1);␊ |
1154 | ␊ |
1155 | #else /* UNALIGNED_OK */␊ |
1156 | ␊ |
1157 | if (match[best_len] != scan_end ||␊ |
1158 | match[best_len-1] != scan_end1 ||␊ |
1159 | *match != *scan ||␊ |
1160 | *++match != scan[1]) continue;␊ |
1161 | ␊ |
1162 | /* The check at best_len-1 can be removed because it will be made␊ |
1163 | * again later. (This heuristic is not always a win.)␊ |
1164 | * It is not necessary to compare scan[2] and match[2] since they␊ |
1165 | * are always equal when the other bytes match, given that␊ |
1166 | * the hash keys are equal and that HASH_BITS >= 8.␊ |
1167 | */␊ |
1168 | scan += 2, match++;␊ |
1169 | Assert(*scan == *match, "match[2]?");␊ |
1170 | ␊ |
1171 | /* We check for insufficient lookahead only every 8th comparison;␊ |
1172 | * the 256th check will be made at strstart+258.␊ |
1173 | */␊ |
1174 | do {␊ |
1175 | } while (*++scan == *++match && *++scan == *++match &&␊ |
1176 | *++scan == *++match && *++scan == *++match &&␊ |
1177 | *++scan == *++match && *++scan == *++match &&␊ |
1178 | *++scan == *++match && *++scan == *++match &&␊ |
1179 | scan < strend);␊ |
1180 | ␊ |
1181 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
1182 | ␊ |
1183 | len = MAX_MATCH - (int)(strend - scan);␊ |
1184 | scan = strend - MAX_MATCH;␊ |
1185 | ␊ |
1186 | #endif /* UNALIGNED_OK */␊ |
1187 | ␊ |
1188 | if (len > best_len) {␊ |
1189 | s->match_start = cur_match;␊ |
1190 | best_len = len;␊ |
1191 | if (len >= nice_match) break;␊ |
1192 | #ifdef UNALIGNED_OK␊ |
1193 | scan_end = *(ushf*)(scan+best_len-1);␊ |
1194 | #else␊ |
1195 | scan_end1 = scan[best_len-1];␊ |
1196 | scan_end = scan[best_len];␊ |
1197 | #endif␊ |
1198 | }␊ |
1199 | } while ((cur_match = prev[cur_match & wmask]) > limit␊ |
1200 | && --chain_length != 0);␊ |
1201 | ␊ |
1202 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len;␊ |
1203 | return s->lookahead;␊ |
1204 | }␊ |
1205 | #endif /* ASMV */␊ |
1206 | ␊ |
1207 | #else /* FASTEST */␊ |
1208 | ␊ |
1209 | /* ---------------------------------------------------------------------------␊ |
1210 | * Optimized version for FASTEST only␊ |
1211 | */␊ |
1212 | local uInt longest_match(s, cur_match)␊ |
1213 | deflate_state *s;␊ |
1214 | IPos cur_match; /* current match */␊ |
1215 | {␊ |
1216 | register Bytef *scan = s->window + s->strstart; /* current string */␊ |
1217 | register Bytef *match; /* matched string */␊ |
1218 | register int len; /* length of current match */␊ |
1219 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;␊ |
1220 | ␊ |
1221 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.␊ |
1222 | * It is easy to get rid of this optimization if necessary.␊ |
1223 | */␊ |
1224 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");␊ |
1225 | ␊ |
1226 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");␊ |
1227 | ␊ |
1228 | Assert(cur_match < s->strstart, "no future");␊ |
1229 | ␊ |
1230 | match = s->window + cur_match;␊ |
1231 | ␊ |
1232 | /* Return failure if the match length is less than 2:␊ |
1233 | */␊ |
1234 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;␊ |
1235 | ␊ |
1236 | /* The check at best_len-1 can be removed because it will be made␊ |
1237 | * again later. (This heuristic is not always a win.)␊ |
1238 | * It is not necessary to compare scan[2] and match[2] since they␊ |
1239 | * are always equal when the other bytes match, given that␊ |
1240 | * the hash keys are equal and that HASH_BITS >= 8.␊ |
1241 | */␊ |
1242 | scan += 2, match += 2;␊ |
1243 | Assert(*scan == *match, "match[2]?");␊ |
1244 | ␊ |
1245 | /* We check for insufficient lookahead only every 8th comparison;␊ |
1246 | * the 256th check will be made at strstart+258.␊ |
1247 | */␊ |
1248 | do {␊ |
1249 | } while (*++scan == *++match && *++scan == *++match &&␊ |
1250 | *++scan == *++match && *++scan == *++match &&␊ |
1251 | *++scan == *++match && *++scan == *++match &&␊ |
1252 | *++scan == *++match && *++scan == *++match &&␊ |
1253 | scan < strend);␊ |
1254 | ␊ |
1255 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
1256 | ␊ |
1257 | len = MAX_MATCH - (int)(strend - scan);␊ |
1258 | ␊ |
1259 | if (len < MIN_MATCH) return MIN_MATCH - 1;␊ |
1260 | ␊ |
1261 | s->match_start = cur_match;␊ |
1262 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;␊ |
1263 | }␊ |
1264 | ␊ |
1265 | #endif /* FASTEST */␊ |
1266 | ␊ |
1267 | #ifdef DEBUG␊ |
1268 | /* ===========================================================================␊ |
1269 | * Check that the match at match_start is indeed a match.␊ |
1270 | */␊ |
1271 | local void check_match(s, start, match, length)␊ |
1272 | deflate_state *s;␊ |
1273 | IPos start, match;␊ |
1274 | int length;␊ |
1275 | {␊ |
1276 | /* check that the match is indeed a match */␊ |
1277 | if (zmemcmp(s->window + match,␊ |
1278 | s->window + start, length) != EQUAL) {␊ |
1279 | fprintf(stderr, " start %u, match %u, length %d\n",␊ |
1280 | start, match, length);␊ |
1281 | do {␊ |
1282 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);␊ |
1283 | } while (--length != 0);␊ |
1284 | z_error("invalid match");␊ |
1285 | }␊ |
1286 | if (z_verbose > 1) {␊ |
1287 | fprintf(stderr,"\\[%d,%d]", start-match, length);␊ |
1288 | do { putc(s->window[start++], stderr); } while (--length != 0);␊ |
1289 | }␊ |
1290 | }␊ |
1291 | #else␊ |
1292 | # define check_match(s, start, match, length)␊ |
1293 | #endif /* DEBUG */␊ |
1294 | ␊ |
1295 | /* ===========================================================================␊ |
1296 | * Fill the window when the lookahead becomes insufficient.␊ |
1297 | * Updates strstart and lookahead.␊ |
1298 | *␊ |
1299 | * IN assertion: lookahead < MIN_LOOKAHEAD␊ |
1300 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD␊ |
1301 | * At least one byte has been read, or avail_in == 0; reads are␊ |
1302 | * performed for at least two bytes (required for the zip translate_eol␊ |
1303 | * option -- not supported here).␊ |
1304 | */␊ |
1305 | local void fill_window(s)␊ |
1306 | deflate_state *s;␊ |
1307 | {␊ |
1308 | register unsigned n, m;␊ |
1309 | register Posf *p;␊ |
1310 | unsigned more; /* Amount of free space at the end of the window. */␊ |
1311 | uInt wsize = s->w_size;␊ |
1312 | ␊ |
1313 | do {␊ |
1314 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);␊ |
1315 | ␊ |
1316 | /* Deal with !@#$% 64K limit: */␊ |
1317 | if (sizeof(int) <= 2) {␊ |
1318 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) {␊ |
1319 | more = wsize;␊ |
1320 | ␊ |
1321 | } else if (more == (unsigned)(-1)) {␊ |
1322 | /* Very unlikely, but possible on 16 bit machine if␊ |
1323 | * strstart == 0 && lookahead == 1 (input done a byte at time)␊ |
1324 | */␊ |
1325 | more--;␊ |
1326 | }␊ |
1327 | }␊ |
1328 | ␊ |
1329 | /* If the window is almost full and there is insufficient lookahead,␊ |
1330 | * move the upper half to the lower one to make room in the upper half.␊ |
1331 | */␊ |
1332 | if (s->strstart >= wsize+MAX_DIST(s)) {␊ |
1333 | ␊ |
1334 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize);␊ |
1335 | s->match_start -= wsize;␊ |
1336 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */␊ |
1337 | s->block_start -= (long) wsize;␊ |
1338 | ␊ |
1339 | /* Slide the hash table (could be avoided with 32 bit values␊ |
1340 | at the expense of memory usage). We slide even when level == 0␊ |
1341 | to keep the hash table consistent if we switch back to level > 0␊ |
1342 | later. (Using level 0 permanently is not an optimal usage of␊ |
1343 | zlib, so we don't care about this pathological case.)␊ |
1344 | */␊ |
1345 | n = s->hash_size;␊ |
1346 | p = &s->head[n];␊ |
1347 | do {␊ |
1348 | m = *--p;␊ |
1349 | *p = (Pos)(m >= wsize ? m-wsize : NIL);␊ |
1350 | } while (--n);␊ |
1351 | ␊ |
1352 | n = wsize;␊ |
1353 | #ifndef FASTEST␊ |
1354 | p = &s->prev[n];␊ |
1355 | do {␊ |
1356 | m = *--p;␊ |
1357 | *p = (Pos)(m >= wsize ? m-wsize : NIL);␊ |
1358 | /* If n is not on any hash chain, prev[n] is garbage but␊ |
1359 | * its value will never be used.␊ |
1360 | */␊ |
1361 | } while (--n);␊ |
1362 | #endif␊ |
1363 | more += wsize;␊ |
1364 | }␊ |
1365 | if (s->strm->avail_in == 0) return;␊ |
1366 | ␊ |
1367 | /* If there was no sliding:␊ |
1368 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&␊ |
1369 | * more == window_size - lookahead - strstart␊ |
1370 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)␊ |
1371 | * => more >= window_size - 2*WSIZE + 2␊ |
1372 | * In the BIG_MEM or MMAP case (not yet supported),␊ |
1373 | * window_size == input_size + MIN_LOOKAHEAD &&␊ |
1374 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.␊ |
1375 | * Otherwise, window_size == 2*WSIZE so more >= 2.␊ |
1376 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2.␊ |
1377 | */␊ |
1378 | Assert(more >= 2, "more < 2");␊ |
1379 | ␊ |
1380 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);␊ |
1381 | s->lookahead += n;␊ |
1382 | ␊ |
1383 | /* Initialize the hash value now that we have some input: */␊ |
1384 | if (s->lookahead >= MIN_MATCH) {␊ |
1385 | s->ins_h = s->window[s->strstart];␊ |
1386 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);␊ |
1387 | #if MIN_MATCH != 3␊ |
1388 | Call UPDATE_HASH() MIN_MATCH-3 more times␊ |
1389 | #endif␊ |
1390 | }␊ |
1391 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,␊ |
1392 | * but this is not important since only literal bytes will be emitted.␊ |
1393 | */␊ |
1394 | ␊ |
1395 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);␊ |
1396 | ␊ |
1397 | /* If the WIN_INIT bytes after the end of the current data have never been␊ |
1398 | * written, then zero those bytes in order to avoid memory check reports of␊ |
1399 | * the use of uninitialized (or uninitialised as Julian writes) bytes by␊ |
1400 | * the longest match routines. Update the high water mark for the next␊ |
1401 | * time through here. WIN_INIT is set to MAX_MATCH since the longest match␊ |
1402 | * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.␊ |
1403 | */␊ |
1404 | if (s->high_water < s->window_size) {␊ |
1405 | ulg curr = s->strstart + (ulg)(s->lookahead);␊ |
1406 | ulg init;␊ |
1407 | ␊ |
1408 | if (s->high_water < curr) {␊ |
1409 | /* Previous high water mark below current data -- zero WIN_INIT␊ |
1410 | * bytes or up to end of window, whichever is less.␊ |
1411 | */␊ |
1412 | init = s->window_size - curr;␊ |
1413 | if (init > WIN_INIT)␊ |
1414 | init = WIN_INIT;␊ |
1415 | zmemzero(s->window + curr, (unsigned)init);␊ |
1416 | s->high_water = curr + init;␊ |
1417 | }␊ |
1418 | else if (s->high_water < (ulg)curr + WIN_INIT) {␊ |
1419 | /* High water mark at or above current data, but below current data␊ |
1420 | * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up␊ |
1421 | * to end of window, whichever is less.␊ |
1422 | */␊ |
1423 | init = (ulg)curr + WIN_INIT - s->high_water;␊ |
1424 | if (init > s->window_size - s->high_water)␊ |
1425 | init = s->window_size - s->high_water;␊ |
1426 | zmemzero(s->window + s->high_water, (unsigned)init);␊ |
1427 | s->high_water += init;␊ |
1428 | }␊ |
1429 | }␊ |
1430 | }␊ |
1431 | ␊ |
1432 | /* ===========================================================================␊ |
1433 | * Flush the current block, with given end-of-file flag.␊ |
1434 | * IN assertion: strstart is set to the end of the current match.␊ |
1435 | */␊ |
1436 | #define FLUSH_BLOCK_ONLY(s, last) { \␊ |
1437 | _tr_flush_block(s, (s->block_start >= 0L ? \␊ |
1438 | (charf *)&s->window[(unsigned)s->block_start] : \␊ |
1439 | (charf *)Z_NULL), \␊ |
1440 | (ulg)((long)s->strstart - s->block_start), \␊ |
1441 | (last)); \␊ |
1442 | s->block_start = s->strstart; \␊ |
1443 | flush_pending(s->strm); \␊ |
1444 | Tracev((stderr,"[FLUSH]")); \␊ |
1445 | }␊ |
1446 | ␊ |
1447 | /* Same but force premature exit if necessary. */␊ |
1448 | #define FLUSH_BLOCK(s, last) { \␊ |
1449 | FLUSH_BLOCK_ONLY(s, last); \␊ |
1450 | if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \␊ |
1451 | }␊ |
1452 | ␊ |
1453 | /* ===========================================================================␊ |
1454 | * Copy without compression as much as possible from the input stream, return␊ |
1455 | * the current block state.␊ |
1456 | * This function does not insert new strings in the dictionary since␊ |
1457 | * uncompressible data is probably not useful. This function is used␊ |
1458 | * only for the level=0 compression option.␊ |
1459 | * NOTE: this function should be optimized to avoid extra copying from␊ |
1460 | * window to pending_buf.␊ |
1461 | */␊ |
1462 | local block_state deflate_stored(s, flush)␊ |
1463 | deflate_state *s;␊ |
1464 | int flush;␊ |
1465 | {␊ |
1466 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited␊ |
1467 | * to pending_buf_size, and each stored block has a 5 byte header:␊ |
1468 | */␊ |
1469 | ulg max_block_size = 0xffff;␊ |
1470 | ulg max_start;␊ |
1471 | ␊ |
1472 | if (max_block_size > s->pending_buf_size - 5) {␊ |
1473 | max_block_size = s->pending_buf_size - 5;␊ |
1474 | }␊ |
1475 | ␊ |
1476 | /* Copy as much as possible from input to output: */␊ |
1477 | for (;;) {␊ |
1478 | /* Fill the window as much as possible: */␊ |
1479 | if (s->lookahead <= 1) {␊ |
1480 | ␊ |
1481 | Assert(s->strstart < s->w_size+MAX_DIST(s) ||␊ |
1482 | s->block_start >= (long)s->w_size, "slide too late");␊ |
1483 | ␊ |
1484 | fill_window(s);␊ |
1485 | if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;␊ |
1486 | ␊ |
1487 | if (s->lookahead == 0) break; /* flush the current block */␊ |
1488 | }␊ |
1489 | Assert(s->block_start >= 0L, "block gone");␊ |
1490 | ␊ |
1491 | s->strstart += s->lookahead;␊ |
1492 | s->lookahead = 0;␊ |
1493 | ␊ |
1494 | /* Emit a stored block if pending_buf will be full: */␊ |
1495 | max_start = s->block_start + max_block_size;␊ |
1496 | if (s->strstart == 0 || (ulg)s->strstart >= max_start) {␊ |
1497 | /* strstart == 0 is possible when wraparound on 16-bit machine */␊ |
1498 | s->lookahead = (uInt)(s->strstart - max_start);␊ |
1499 | s->strstart = (uInt)max_start;␊ |
1500 | FLUSH_BLOCK(s, 0);␊ |
1501 | }␊ |
1502 | /* Flush if we may have to slide, otherwise block_start may become␊ |
1503 | * negative and the data will be gone:␊ |
1504 | */␊ |
1505 | if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {␊ |
1506 | FLUSH_BLOCK(s, 0);␊ |
1507 | }␊ |
1508 | }␊ |
1509 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
1510 | return flush == Z_FINISH ? finish_done : block_done;␊ |
1511 | }␊ |
1512 | ␊ |
1513 | /* ===========================================================================␊ |
1514 | * Compress as much as possible from the input stream, return the current␊ |
1515 | * block state.␊ |
1516 | * This function does not perform lazy evaluation of matches and inserts␊ |
1517 | * new strings in the dictionary only for unmatched strings or for short␊ |
1518 | * matches. It is used only for the fast compression options.␊ |
1519 | */␊ |
1520 | local block_state deflate_fast(s, flush)␊ |
1521 | deflate_state *s;␊ |
1522 | int flush;␊ |
1523 | {␊ |
1524 | IPos hash_head; /* head of the hash chain */␊ |
1525 | int bflush; /* set if current block must be flushed */␊ |
1526 | ␊ |
1527 | for (;;) {␊ |
1528 | /* Make sure that we always have enough lookahead, except␊ |
1529 | * at the end of the input file. We need MAX_MATCH bytes␊ |
1530 | * for the next match, plus MIN_MATCH bytes to insert the␊ |
1531 | * string following the next match.␊ |
1532 | */␊ |
1533 | if (s->lookahead < MIN_LOOKAHEAD) {␊ |
1534 | fill_window(s);␊ |
1535 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {␊ |
1536 | return need_more;␊ |
1537 | }␊ |
1538 | if (s->lookahead == 0) break; /* flush the current block */␊ |
1539 | }␊ |
1540 | ␊ |
1541 | /* Insert the string window[strstart .. strstart+2] in the␊ |
1542 | * dictionary, and set hash_head to the head of the hash chain:␊ |
1543 | */␊ |
1544 | hash_head = NIL;␊ |
1545 | if (s->lookahead >= MIN_MATCH) {␊ |
1546 | INSERT_STRING(s, s->strstart, hash_head);␊ |
1547 | }␊ |
1548 | ␊ |
1549 | /* Find the longest match, discarding those <= prev_length.␊ |
1550 | * At this point we have always match_length < MIN_MATCH␊ |
1551 | */␊ |
1552 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {␊ |
1553 | /* To simplify the code, we prevent matches with the string␊ |
1554 | * of window index 0 (in particular we have to avoid a match␊ |
1555 | * of the string with itself at the start of the input file).␊ |
1556 | */␊ |
1557 | s->match_length = longest_match (s, hash_head);␊ |
1558 | /* longest_match() sets match_start */␊ |
1559 | }␊ |
1560 | if (s->match_length >= MIN_MATCH) {␊ |
1561 | check_match(s, s->strstart, s->match_start, s->match_length);␊ |
1562 | ␊ |
1563 | _tr_tally_dist(s, s->strstart - s->match_start,␊ |
1564 | s->match_length - MIN_MATCH, bflush);␊ |
1565 | ␊ |
1566 | s->lookahead -= s->match_length;␊ |
1567 | ␊ |
1568 | /* Insert new strings in the hash table only if the match length␊ |
1569 | * is not too large. This saves time but degrades compression.␊ |
1570 | */␊ |
1571 | #ifndef FASTEST␊ |
1572 | if (s->match_length <= s->max_insert_length &&␊ |
1573 | s->lookahead >= MIN_MATCH) {␊ |
1574 | s->match_length--; /* string at strstart already in table */␊ |
1575 | do {␊ |
1576 | s->strstart++;␊ |
1577 | INSERT_STRING(s, s->strstart, hash_head);␊ |
1578 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are␊ |
1579 | * always MIN_MATCH bytes ahead.␊ |
1580 | */␊ |
1581 | } while (--s->match_length != 0);␊ |
1582 | s->strstart++;␊ |
1583 | } else␊ |
1584 | #endif␊ |
1585 | {␊ |
1586 | s->strstart += s->match_length;␊ |
1587 | s->match_length = 0;␊ |
1588 | s->ins_h = s->window[s->strstart];␊ |
1589 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);␊ |
1590 | #if MIN_MATCH != 3␊ |
1591 | Call UPDATE_HASH() MIN_MATCH-3 more times␊ |
1592 | #endif␊ |
1593 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not␊ |
1594 | * matter since it will be recomputed at next deflate call.␊ |
1595 | */␊ |
1596 | }␊ |
1597 | } else {␊ |
1598 | /* No match, output a literal byte */␊ |
1599 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
1600 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
1601 | s->lookahead--;␊ |
1602 | s->strstart++;␊ |
1603 | }␊ |
1604 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
1605 | }␊ |
1606 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
1607 | return flush == Z_FINISH ? finish_done : block_done;␊ |
1608 | }␊ |
1609 | ␊ |
1610 | #ifndef FASTEST␊ |
1611 | /* ===========================================================================␊ |
1612 | * Same as above, but achieves better compression. We use a lazy␊ |
1613 | * evaluation for matches: a match is finally adopted only if there is␊ |
1614 | * no better match at the next window position.␊ |
1615 | */␊ |
1616 | local block_state deflate_slow(s, flush)␊ |
1617 | deflate_state *s;␊ |
1618 | int flush;␊ |
1619 | {␊ |
1620 | IPos hash_head; /* head of hash chain */␊ |
1621 | int bflush; /* set if current block must be flushed */␊ |
1622 | ␊ |
1623 | /* Process the input block. */␊ |
1624 | for (;;) {␊ |
1625 | /* Make sure that we always have enough lookahead, except␊ |
1626 | * at the end of the input file. We need MAX_MATCH bytes␊ |
1627 | * for the next match, plus MIN_MATCH bytes to insert the␊ |
1628 | * string following the next match.␊ |
1629 | */␊ |
1630 | if (s->lookahead < MIN_LOOKAHEAD) {␊ |
1631 | fill_window(s);␊ |
1632 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {␊ |
1633 | return need_more;␊ |
1634 | }␊ |
1635 | if (s->lookahead == 0) break; /* flush the current block */␊ |
1636 | }␊ |
1637 | ␊ |
1638 | /* Insert the string window[strstart .. strstart+2] in the␊ |
1639 | * dictionary, and set hash_head to the head of the hash chain:␊ |
1640 | */␊ |
1641 | hash_head = NIL;␊ |
1642 | if (s->lookahead >= MIN_MATCH) {␊ |
1643 | INSERT_STRING(s, s->strstart, hash_head);␊ |
1644 | }␊ |
1645 | ␊ |
1646 | /* Find the longest match, discarding those <= prev_length.␊ |
1647 | */␊ |
1648 | s->prev_length = s->match_length, s->prev_match = s->match_start;␊ |
1649 | s->match_length = MIN_MATCH-1;␊ |
1650 | ␊ |
1651 | if (hash_head != NIL && s->prev_length < s->max_lazy_match &&␊ |
1652 | s->strstart - hash_head <= MAX_DIST(s)) {␊ |
1653 | /* To simplify the code, we prevent matches with the string␊ |
1654 | * of window index 0 (in particular we have to avoid a match␊ |
1655 | * of the string with itself at the start of the input file).␊ |
1656 | */␊ |
1657 | s->match_length = longest_match (s, hash_head);␊ |
1658 | /* longest_match() sets match_start */␊ |
1659 | ␊ |
1660 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED␊ |
1661 | #if TOO_FAR <= 32767␊ |
1662 | || (s->match_length == MIN_MATCH &&␊ |
1663 | s->strstart - s->match_start > TOO_FAR)␊ |
1664 | #endif␊ |
1665 | )) {␊ |
1666 | ␊ |
1667 | /* If prev_match is also MIN_MATCH, match_start is garbage␊ |
1668 | * but we will ignore the current match anyway.␊ |
1669 | */␊ |
1670 | s->match_length = MIN_MATCH-1;␊ |
1671 | }␊ |
1672 | }␊ |
1673 | /* If there was a match at the previous step and the current␊ |
1674 | * match is not better, output the previous match:␊ |
1675 | */␊ |
1676 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {␊ |
1677 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;␊ |
1678 | /* Do not insert strings in hash table beyond this. */␊ |
1679 | ␊ |
1680 | check_match(s, s->strstart-1, s->prev_match, s->prev_length);␊ |
1681 | ␊ |
1682 | _tr_tally_dist(s, s->strstart -1 - s->prev_match,␊ |
1683 | s->prev_length - MIN_MATCH, bflush);␊ |
1684 | ␊ |
1685 | /* Insert in hash table all strings up to the end of the match.␊ |
1686 | * strstart-1 and strstart are already inserted. If there is not␊ |
1687 | * enough lookahead, the last two strings are not inserted in␊ |
1688 | * the hash table.␊ |
1689 | */␊ |
1690 | s->lookahead -= s->prev_length-1;␊ |
1691 | s->prev_length -= 2;␊ |
1692 | do {␊ |
1693 | if (++s->strstart <= max_insert) {␊ |
1694 | INSERT_STRING(s, s->strstart, hash_head);␊ |
1695 | }␊ |
1696 | } while (--s->prev_length != 0);␊ |
1697 | s->match_available = 0;␊ |
1698 | s->match_length = MIN_MATCH-1;␊ |
1699 | s->strstart++;␊ |
1700 | ␊ |
1701 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
1702 | ␊ |
1703 | } else if (s->match_available) {␊ |
1704 | /* If there was no match at the previous position, output a␊ |
1705 | * single literal. If there was a match but the current match␊ |
1706 | * is longer, truncate the previous match to a single literal.␊ |
1707 | */␊ |
1708 | Tracevv((stderr,"%c", s->window[s->strstart-1]));␊ |
1709 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);␊ |
1710 | if (bflush) {␊ |
1711 | FLUSH_BLOCK_ONLY(s, 0);␊ |
1712 | }␊ |
1713 | s->strstart++;␊ |
1714 | s->lookahead--;␊ |
1715 | if (s->strm->avail_out == 0) return need_more;␊ |
1716 | } else {␊ |
1717 | /* There is no previous match to compare with, wait for␊ |
1718 | * the next step to decide.␊ |
1719 | */␊ |
1720 | s->match_available = 1;␊ |
1721 | s->strstart++;␊ |
1722 | s->lookahead--;␊ |
1723 | }␊ |
1724 | }␊ |
1725 | Assert (flush != Z_NO_FLUSH, "no flush?");␊ |
1726 | if (s->match_available) {␊ |
1727 | Tracevv((stderr,"%c", s->window[s->strstart-1]));␊ |
1728 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);␊ |
1729 | s->match_available = 0;␊ |
1730 | }␊ |
1731 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
1732 | return flush == Z_FINISH ? finish_done : block_done;␊ |
1733 | }␊ |
1734 | #endif /* FASTEST */␊ |
1735 | ␊ |
1736 | /* ===========================================================================␊ |
1737 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance␊ |
1738 | * one. Do not maintain a hash table. (It will be regenerated if this run of␊ |
1739 | * deflate switches away from Z_RLE.)␊ |
1740 | */␊ |
1741 | local block_state deflate_rle(s, flush)␊ |
1742 | deflate_state *s;␊ |
1743 | int flush;␊ |
1744 | {␊ |
1745 | int bflush; /* set if current block must be flushed */␊ |
1746 | uInt prev; /* byte at distance one to match */␊ |
1747 | Bytef *scan, *strend; /* scan goes up to strend for length of run */␊ |
1748 | ␊ |
1749 | for (;;) {␊ |
1750 | /* Make sure that we always have enough lookahead, except␊ |
1751 | * at the end of the input file. We need MAX_MATCH bytes␊ |
1752 | * for the longest encodable run.␊ |
1753 | */␊ |
1754 | if (s->lookahead < MAX_MATCH) {␊ |
1755 | fill_window(s);␊ |
1756 | if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {␊ |
1757 | return need_more;␊ |
1758 | }␊ |
1759 | if (s->lookahead == 0) break; /* flush the current block */␊ |
1760 | }␊ |
1761 | ␊ |
1762 | /* See how many times the previous byte repeats */␊ |
1763 | s->match_length = 0;␊ |
1764 | if (s->lookahead >= MIN_MATCH && s->strstart > 0) {␊ |
1765 | scan = s->window + s->strstart - 1;␊ |
1766 | prev = *scan;␊ |
1767 | if (prev == *++scan && prev == *++scan && prev == *++scan) {␊ |
1768 | strend = s->window + s->strstart + MAX_MATCH;␊ |
1769 | do {␊ |
1770 | } while (prev == *++scan && prev == *++scan &&␊ |
1771 | prev == *++scan && prev == *++scan &&␊ |
1772 | prev == *++scan && prev == *++scan &&␊ |
1773 | prev == *++scan && prev == *++scan &&␊ |
1774 | scan < strend);␊ |
1775 | s->match_length = MAX_MATCH - (int)(strend - scan);␊ |
1776 | if (s->match_length > s->lookahead)␊ |
1777 | s->match_length = s->lookahead;␊ |
1778 | }␊ |
1779 | }␊ |
1780 | ␊ |
1781 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */␊ |
1782 | if (s->match_length >= MIN_MATCH) {␊ |
1783 | check_match(s, s->strstart, s->strstart - 1, s->match_length);␊ |
1784 | ␊ |
1785 | _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);␊ |
1786 | ␊ |
1787 | s->lookahead -= s->match_length;␊ |
1788 | s->strstart += s->match_length;␊ |
1789 | s->match_length = 0;␊ |
1790 | } else {␊ |
1791 | /* No match, output a literal byte */␊ |
1792 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
1793 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
1794 | s->lookahead--;␊ |
1795 | s->strstart++;␊ |
1796 | }␊ |
1797 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
1798 | }␊ |
1799 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
1800 | return flush == Z_FINISH ? finish_done : block_done;␊ |
1801 | }␊ |
1802 | ␊ |
1803 | /* ===========================================================================␊ |
1804 | * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.␊ |
1805 | * (It will be regenerated if this run of deflate switches away from Huffman.)␊ |
1806 | */␊ |
1807 | local block_state deflate_huff(s, flush)␊ |
1808 | deflate_state *s;␊ |
1809 | int flush;␊ |
1810 | {␊ |
1811 | int bflush; /* set if current block must be flushed */␊ |
1812 | ␊ |
1813 | for (;;) {␊ |
1814 | /* Make sure that we have a literal to write. */␊ |
1815 | if (s->lookahead == 0) {␊ |
1816 | fill_window(s);␊ |
1817 | if (s->lookahead == 0) {␊ |
1818 | if (flush == Z_NO_FLUSH)␊ |
1819 | return need_more;␊ |
1820 | break; /* flush the current block */␊ |
1821 | }␊ |
1822 | }␊ |
1823 | ␊ |
1824 | /* Output a literal byte */␊ |
1825 | s->match_length = 0;␊ |
1826 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
1827 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
1828 | s->lookahead--;␊ |
1829 | s->strstart++;␊ |
1830 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
1831 | }␊ |
1832 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
1833 | return flush == Z_FINISH ? finish_done : block_done;␊ |
1834 | }␊ |
1835 |