1/* 2 * Copyright (c) 2008 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* deflate.c -- compress data using the deflation algorithm 29 * Copyright (C) 1995-2005 Jean-loup Gailly. 30 * For conditions of distribution and use, see copyright notice in zlib.h 31 */ 32 33/* 34 * ALGORITHM 35 * 36 * The "deflation" process depends on being able to identify portions 37 * of the input text which are identical to earlier input (within a 38 * sliding window trailing behind the input currently being processed). 39 * 40 * The most straightforward technique turns out to be the fastest for 41 * most input files: try all possible matches and select the longest. 42 * The key feature of this algorithm is that insertions into the string 43 * dictionary are very simple and thus fast, and deletions are avoided 44 * completely. Insertions are performed at each input character, whereas 45 * string matches are performed only when the previous match ends. So it 46 * is preferable to spend more time in matches to allow very fast string 47 * insertions and avoid deletions. The matching algorithm for small 48 * strings is inspired from that of Rabin & Karp. A brute force approach 49 * is used to find longer strings when a small match has been found. 50 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze 51 * (by Leonid Broukhis). 52 * A previous version of this file used a more sophisticated algorithm 53 * (by Fiala and Greene) which is guaranteed to run in linear amortized 54 * time, but has a larger average cost, uses more memory and is patented. 55 * However the F&G algorithm may be faster for some highly redundant 56 * files if the parameter max_chain_length (described below) is too large. 57 * 58 * ACKNOWLEDGEMENTS 59 * 60 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and 61 * I found it in 'freeze' written by Leonid Broukhis. 62 * Thanks to many people for bug reports and testing. 63 * 64 * REFERENCES 65 * 66 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". 67 * Available in http://www.ietf.org/rfc/rfc1951.txt 68 * 69 * A description of the Rabin and Karp algorithm is given in the book 70 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. 71 * 72 * Fiala,E.R., and Greene,D.H. 73 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 74 * 75 */ 76 77/* @(#) $Id$ */ 78 79#include "deflate.h" 80 81const char deflate_copyright[] = 82 " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; 83/* 84 If you use the zlib library in a product, an acknowledgment is welcome 85 in the documentation of your product. If for some reason you cannot 86 include such an acknowledgment, I would appreciate that you keep this 87 copyright string in the executable of your product. 88 */ 89 90/* =========================================================================== 91 * Function prototypes. 92 */ 93typedef enum { 94 need_more, /* block not completed, need more input or more output */ 95 block_done, /* block flush performed */ 96 finish_started, /* finish started, need only more output at next deflate */ 97 finish_done /* finish done, accept no more input or output */ 98} block_state; 99 100typedef block_state (*compress_func) OF((deflate_state *s, int flush)); 101/* Compression function. Returns the block state after the call. */ 102 103local void fill_window OF((deflate_state *s)); 104local block_state deflate_stored OF((deflate_state *s, int flush)); 105local block_state deflate_fast OF((deflate_state *s, int flush)); 106#ifndef FASTEST 107local block_state deflate_slow OF((deflate_state *s, int flush)); 108#endif 109local void lm_init OF((deflate_state *s)); 110local void putShortMSB OF((deflate_state *s, uInt b)); 111local void flush_pending OF((z_streamp strm)); 112local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); 113#ifndef FASTEST 114#ifdef ASMV 115 void match_init OF((void)); /* asm code initialization */ 116 uInt longest_match OF((deflate_state *s, IPos cur_match)); 117#else 118local uInt longest_match OF((deflate_state *s, IPos cur_match)); 119#endif 120#endif 121local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); 122 123#ifdef DEBUG 124local void check_match OF((deflate_state *s, IPos start, IPos match, 125 int length)); 126#endif 127 128/* =========================================================================== 129 * Local data 130 */ 131 132#define NIL 0 133/* Tail of hash chains */ 134 135#ifndef TOO_FAR 136# define TOO_FAR 4096 137#endif 138/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ 139 140#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) 141/* Minimum amount of lookahead, except at the end of the input file. 142 * See deflate.c for comments about the MIN_MATCH+1. 143 */ 144 145/* Values for max_lazy_match, good_match and max_chain_length, depending on 146 * the desired pack level (0..9). The values given below have been tuned to 147 * exclude worst case performance for pathological files. Better values may be 148 * found for specific files. 149 */ 150typedef struct config_s { 151 ush good_length; /* reduce lazy search above this match length */ 152 ush max_lazy; /* do not perform lazy search above this match length */ 153 ush nice_length; /* quit search above this match length */ 154 ush max_chain; 155 compress_func func; 156} config; 157 158#ifdef FASTEST 159local const config configuration_table[2] = { 160/* good lazy nice chain */ 161/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 162/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ 163#else 164local const config configuration_table[10] = { 165/* good lazy nice chain */ 166/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 167/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ 168/* 2 */ {4, 5, 16, 8, deflate_fast}, 169/* 3 */ {4, 6, 32, 32, deflate_fast}, 170 171/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ 172/* 5 */ {8, 16, 32, 32, deflate_slow}, 173/* 6 */ {8, 16, 128, 128, deflate_slow}, 174/* 7 */ {8, 32, 128, 256, deflate_slow}, 175/* 8 */ {32, 128, 258, 1024, deflate_slow}, 176/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ 177#endif 178 179/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 180 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different 181 * meaning. 182 */ 183 184#define EQUAL 0 185/* result of memcmp for equal strings */ 186 187#ifndef NO_DUMMY_DECL 188struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ 189#endif 190 191/* =========================================================================== 192 * Update a hash value with the given input byte 193 * IN assertion: all calls to to UPDATE_HASH are made with consecutive 194 * input characters, so that a running hash key can be computed from the 195 * previous key instead of complete recalculation each time. 196 */ 197#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) 198 199 200/* =========================================================================== 201 * Insert string str in the dictionary and set match_head to the previous head 202 * of the hash chain (the most recent string with same hash key). Return 203 * the previous length of the hash chain. 204 * If this file is compiled with -DFASTEST, the compression level is forced 205 * to 1, and no hash chains are maintained. 206 * IN assertion: all calls to to INSERT_STRING are made with consecutive 207 * input characters and the first MIN_MATCH bytes of str are valid 208 * (except for the last MIN_MATCH-1 bytes of the input file). 209 */ 210#ifdef FASTEST 211#define INSERT_STRING(s, str, match_head) \ 212 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 213 match_head = s->head[s->ins_h], \ 214 s->head[s->ins_h] = (Pos)(str)) 215#else 216#define INSERT_STRING(s, str, match_head) \ 217 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 218 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ 219 s->head[s->ins_h] = (Pos)(str)) 220#endif 221 222/* =========================================================================== 223 * Initialize the hash table (avoiding 64K overflow for 16 bit systems). 224 * prev[] will be initialized on the fly. 225 */ 226#define CLEAR_HASH(s) \ 227 s->head[s->hash_size-1] = NIL; \ 228 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); 229 230/* ========================================================================= */ 231int ZEXPORT deflateInit_(strm, level, version, stream_size) 232 z_streamp strm; 233 int level; 234 const char *version; 235 int stream_size; 236{ 237 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, 238 Z_DEFAULT_STRATEGY, version, stream_size); 239 /* To do: ignore strm->next_in if we use it as window */ 240} 241 242/* ========================================================================= */ 243int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, 244 version, stream_size) 245 z_streamp strm; 246 int level; 247 int method; 248 int windowBits; 249 int memLevel; 250 int strategy; 251 const char *version; 252 int stream_size; 253{ 254 deflate_state *s; 255 int wrap = 1; 256 static const char my_version[] = ZLIB_VERSION; 257 258 ushf *overlay; 259 /* We overlay pending_buf and d_buf+l_buf. This works since the average 260 * output size for (length,distance) codes is <= 24 bits. 261 */ 262 263 if (version == Z_NULL || version[0] != my_version[0] || 264 stream_size != sizeof(z_stream)) { 265 return Z_VERSION_ERROR; 266 } 267 if (strm == Z_NULL) return Z_STREAM_ERROR; 268 269 strm->msg = Z_NULL; 270#ifndef NO_ZCFUNCS 271 if (strm->zalloc == (alloc_func)0) { 272 strm->zalloc = zcalloc; 273 strm->opaque = (voidpf)0; 274 } 275 if (strm->zfree == (free_func)0) strm->zfree = zcfree; 276#endif /* NO_ZCFUNCS */ 277 278#ifdef FASTEST 279 if (level != 0) level = 1; 280#else 281 if (level == Z_DEFAULT_COMPRESSION) level = 6; 282#endif 283 284 if (windowBits < 0) { /* suppress zlib wrapper */ 285 wrap = 0; 286 windowBits = -windowBits; 287 } 288#ifdef GZIP 289 else if (windowBits > 15) { 290 wrap = 2; /* write gzip wrapper instead */ 291 windowBits -= 16; 292 } 293#endif 294 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || 295 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || 296 strategy < 0 || strategy > Z_FIXED) { 297 return Z_STREAM_ERROR; 298 } 299 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ 300 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); 301 if (s == Z_NULL) return Z_MEM_ERROR; 302 strm->state = (struct internal_state FAR *)s; 303 s->strm = strm; 304 305 s->wrap = wrap; 306 s->gzhead = Z_NULL; 307 s->w_bits = windowBits; 308 s->w_size = 1 << s->w_bits; 309 s->w_mask = s->w_size - 1; 310 311 s->hash_bits = memLevel + 7; 312 s->hash_size = 1 << s->hash_bits; 313 s->hash_mask = s->hash_size - 1; 314 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); 315 316 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); 317 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); 318 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); 319 320 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ 321 322 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); 323 s->pending_buf = (uchf *) overlay; 324 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); 325 326 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || 327 s->pending_buf == Z_NULL) { 328 s->status = FINISH_STATE; 329 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); 330 deflateEnd (strm); 331 return Z_MEM_ERROR; 332 } 333 s->d_buf = overlay + s->lit_bufsize/sizeof(ush); 334 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; 335 336 s->level = level; 337 s->strategy = strategy; 338 s->method = (Byte)method; 339 340 return deflateReset(strm); 341} 342 343/* ========================================================================= */ 344int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) 345 z_streamp strm; 346 const Bytef *dictionary; 347 uInt dictLength; 348{ 349 deflate_state *s; 350 uInt length = dictLength; 351 uInt n; 352 IPos hash_head = 0; 353 354 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || 355 strm->state->wrap == 2 || 356 (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) 357 return Z_STREAM_ERROR; 358 359 s = strm->state; 360 if (s->wrap) 361 strm->adler = adler32(strm->adler, dictionary, dictLength); 362 363 if (length < MIN_MATCH) return Z_OK; 364 if (length > MAX_DIST(s)) { 365 length = MAX_DIST(s); 366 dictionary += dictLength - length; /* use the tail of the dictionary */ 367 } 368 zmemcpy(s->window, dictionary, length); 369 s->strstart = length; 370 s->block_start = (long)length; 371 372 /* Insert all strings in the hash table (except for the last two bytes). 373 * s->lookahead stays null, so s->ins_h will be recomputed at the next 374 * call of fill_window. 375 */ 376 s->ins_h = s->window[0]; 377 UPDATE_HASH(s, s->ins_h, s->window[1]); 378 for (n = 0; n <= length - MIN_MATCH; n++) { 379 INSERT_STRING(s, n, hash_head); 380 } 381 if (hash_head) hash_head = 0; /* to make compiler happy */ 382 return Z_OK; 383} 384 385/* ========================================================================= */ 386int ZEXPORT deflateReset (strm) 387 z_streamp strm; 388{ 389 deflate_state *s; 390 391 if (strm == Z_NULL || strm->state == Z_NULL || 392 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { 393 return Z_STREAM_ERROR; 394 } 395 396 strm->total_in = strm->total_out = 0; 397 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ 398 strm->data_type = Z_UNKNOWN; 399 400 s = (deflate_state *)strm->state; 401 s->pending = 0; 402 s->pending_out = s->pending_buf; 403 404 if (s->wrap < 0) { 405 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ 406 } 407 s->status = s->wrap ? INIT_STATE : BUSY_STATE; 408 strm->adler = 409#ifdef GZIP 410 s->wrap == 2 ? z_crc32(0L, Z_NULL, 0) : 411#endif 412 adler32(0L, Z_NULL, 0); 413 s->last_flush = Z_NO_FLUSH; 414 415 _tr_init(s); 416 lm_init(s); 417 418 return Z_OK; 419} 420 421/* ========================================================================= */ 422int ZEXPORT deflateSetHeader (strm, head) 423 z_streamp strm; 424 gz_headerp head; 425{ 426 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 427 if (strm->state->wrap != 2) return Z_STREAM_ERROR; 428 strm->state->gzhead = head; 429 return Z_OK; 430} 431 432/* ========================================================================= */ 433int ZEXPORT deflatePrime (strm, bits, value) 434 z_streamp strm; 435 int bits; 436 int value; 437{ 438 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 439 strm->state->bi_valid = bits; 440 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); 441 return Z_OK; 442} 443 444/* ========================================================================= */ 445int ZEXPORT deflateParams(strm, level, strategy) 446 z_streamp strm; 447 int level; 448 int strategy; 449{ 450 deflate_state *s; 451 compress_func func; 452 int err = Z_OK; 453 454 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 455 s = strm->state; 456 457#ifdef FASTEST 458 if (level != 0) level = 1; 459#else 460 if (level == Z_DEFAULT_COMPRESSION) level = 6; 461#endif 462 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { 463 return Z_STREAM_ERROR; 464 } 465 func = configuration_table[s->level].func; 466 467 if (func != configuration_table[level].func && strm->total_in != 0) { 468 /* Flush the last buffer: */ 469 err = deflate(strm, Z_PARTIAL_FLUSH); 470 } 471 if (s->level != level) { 472 s->level = level; 473 s->max_lazy_match = configuration_table[level].max_lazy; 474 s->good_match = configuration_table[level].good_length; 475 s->nice_match = configuration_table[level].nice_length; 476 s->max_chain_length = configuration_table[level].max_chain; 477 } 478 s->strategy = strategy; 479 return err; 480} 481 482/* ========================================================================= */ 483int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) 484 z_streamp strm; 485 int good_length; 486 int max_lazy; 487 int nice_length; 488 int max_chain; 489{ 490 deflate_state *s; 491 492 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 493 s = strm->state; 494 s->good_match = good_length; 495 s->max_lazy_match = max_lazy; 496 s->nice_match = nice_length; 497 s->max_chain_length = max_chain; 498 return Z_OK; 499} 500 501/* ========================================================================= 502 * For the default windowBits of 15 and memLevel of 8, this function returns 503 * a close to exact, as well as small, upper bound on the compressed size. 504 * They are coded as constants here for a reason--if the #define's are 505 * changed, then this function needs to be changed as well. The return 506 * value for 15 and 8 only works for those exact settings. 507 * 508 * For any setting other than those defaults for windowBits and memLevel, 509 * the value returned is a conservative worst case for the maximum expansion 510 * resulting from using fixed blocks instead of stored blocks, which deflate 511 * can emit on compressed data for some combinations of the parameters. 512 * 513 * This function could be more sophisticated to provide closer upper bounds 514 * for every combination of windowBits and memLevel, as well as wrap. 515 * But even the conservative upper bound of about 14% expansion does not 516 * seem onerous for output buffer allocation. 517 */ 518uLong ZEXPORT deflateBound(strm, sourceLen) 519 z_streamp strm; 520 uLong sourceLen; 521{ 522 deflate_state *s; 523 uLong destLen; 524 525 /* conservative upper bound */ 526 destLen = sourceLen + 527 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; 528 529 /* if can't get parameters, return conservative bound */ 530 if (strm == Z_NULL || strm->state == Z_NULL) 531 return destLen; 532 533 /* if not default parameters, return conservative bound */ 534 s = strm->state; 535 if (s->w_bits != 15 || s->hash_bits != 8 + 7) 536 return destLen; 537 538 /* default settings: return tight bound for that case */ 539 return compressBound(sourceLen); 540} 541 542/* ========================================================================= 543 * Put a short in the pending buffer. The 16-bit value is put in MSB order. 544 * IN assertion: the stream state is correct and there is enough room in 545 * pending_buf. 546 */ 547local void putShortMSB (s, b) 548 deflate_state *s; 549 uInt b; 550{ 551 put_byte(s, (Byte)(b >> 8)); 552 put_byte(s, (Byte)(b & 0xff)); 553} 554 555/* ========================================================================= 556 * Flush as much pending output as possible. All deflate() output goes 557 * through this function so some applications may wish to modify it 558 * to avoid allocating a large strm->next_out buffer and copying into it. 559 * (See also read_buf()). 560 */ 561local void flush_pending(strm) 562 z_streamp strm; 563{ 564 unsigned len = strm->state->pending; 565 566 if (len > strm->avail_out) len = strm->avail_out; 567 if (len == 0) return; 568 569 zmemcpy(strm->next_out, strm->state->pending_out, len); 570 strm->next_out += len; 571 strm->state->pending_out += len; 572 strm->total_out += len; 573 strm->avail_out -= len; 574 strm->state->pending -= len; 575 if (strm->state->pending == 0) { 576 strm->state->pending_out = strm->state->pending_buf; 577 } 578} 579 580/* ========================================================================= */ 581int ZEXPORT deflate (strm, flush) 582 z_streamp strm; 583 int flush; 584{ 585 int old_flush; /* value of flush param for previous deflate call */ 586 deflate_state *s; 587 588 if (strm == Z_NULL || strm->state == Z_NULL || 589 flush > Z_FINISH || flush < 0) { 590 return Z_STREAM_ERROR; 591 } 592 s = strm->state; 593 594 if (strm->next_out == Z_NULL || 595 (strm->next_in == Z_NULL && strm->avail_in != 0) || 596 (s->status == FINISH_STATE && flush != Z_FINISH)) { 597 ERR_RETURN(strm, Z_STREAM_ERROR); 598 } 599 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 600 601 s->strm = strm; /* just in case */ 602 old_flush = s->last_flush; 603 s->last_flush = flush; 604 605 /* Write the header */ 606 if (s->status == INIT_STATE) { 607#ifdef GZIP 608 if (s->wrap == 2) { 609 strm->adler = z_crc32(0L, Z_NULL, 0); 610 put_byte(s, 31); 611 put_byte(s, 139); 612 put_byte(s, 8); 613 if (s->gzhead == NULL) { 614 put_byte(s, 0); 615 put_byte(s, 0); 616 put_byte(s, 0); 617 put_byte(s, 0); 618 put_byte(s, 0); 619 put_byte(s, s->level == 9 ? 2 : 620 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 621 4 : 0)); 622 put_byte(s, OS_CODE); 623 s->status = BUSY_STATE; 624 } 625 else { 626 put_byte(s, (s->gzhead->text ? 1 : 0) + 627 (s->gzhead->hcrc ? 2 : 0) + 628 (s->gzhead->extra == Z_NULL ? 0 : 4) + 629 (s->gzhead->name == Z_NULL ? 0 : 8) + 630 (s->gzhead->comment == Z_NULL ? 0 : 16) 631 ); 632 put_byte(s, (Byte)(s->gzhead->time & 0xff)); 633 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); 634 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); 635 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); 636 put_byte(s, s->level == 9 ? 2 : 637 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 638 4 : 0)); 639 put_byte(s, s->gzhead->os & 0xff); 640 if (s->gzhead->extra != NULL) { 641 put_byte(s, s->gzhead->extra_len & 0xff); 642 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); 643 } 644 if (s->gzhead->hcrc) 645 strm->adler = z_crc32(strm->adler, s->pending_buf, 646 s->pending); 647 s->gzindex = 0; 648 s->status = EXTRA_STATE; 649 } 650 } 651 else 652#endif 653 { 654 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 655 uInt level_flags; 656 657 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 658 level_flags = 0; 659 else if (s->level < 6) 660 level_flags = 1; 661 else if (s->level == 6) 662 level_flags = 2; 663 else 664 level_flags = 3; 665 header |= (level_flags << 6); 666 if (s->strstart != 0) header |= PRESET_DICT; 667 header += 31 - (header % 31); 668 669 s->status = BUSY_STATE; 670 putShortMSB(s, header); 671 672 /* Save the adler32 of the preset dictionary: */ 673 if (s->strstart != 0) { 674 putShortMSB(s, (uInt)(strm->adler >> 16)); 675 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 676 } 677 strm->adler = adler32(0L, Z_NULL, 0); 678 } 679 } 680#ifdef GZIP 681 if (s->status == EXTRA_STATE) { 682 if (s->gzhead->extra != NULL) { 683 uInt beg = s->pending; /* start of bytes to update crc */ 684 685 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { 686 if (s->pending == s->pending_buf_size) { 687 if (s->gzhead->hcrc && s->pending > beg) 688 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 689 s->pending - beg); 690 flush_pending(strm); 691 beg = s->pending; 692 if (s->pending == s->pending_buf_size) 693 break; 694 } 695 put_byte(s, s->gzhead->extra[s->gzindex]); 696 s->gzindex++; 697 } 698 if (s->gzhead->hcrc && s->pending > beg) 699 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 700 s->pending - beg); 701 if (s->gzindex == s->gzhead->extra_len) { 702 s->gzindex = 0; 703 s->status = NAME_STATE; 704 } 705 } 706 else 707 s->status = NAME_STATE; 708 } 709 if (s->status == NAME_STATE) { 710 if (s->gzhead->name != NULL) { 711 uInt beg = s->pending; /* start of bytes to update crc */ 712 int val; 713 714 do { 715 if (s->pending == s->pending_buf_size) { 716 if (s->gzhead->hcrc && s->pending > beg) 717 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 718 s->pending - beg); 719 flush_pending(strm); 720 beg = s->pending; 721 if (s->pending == s->pending_buf_size) { 722 val = 1; 723 break; 724 } 725 } 726 val = s->gzhead->name[s->gzindex++]; 727 put_byte(s, val); 728 } while (val != 0); 729 if (s->gzhead->hcrc && s->pending > beg) 730 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 731 s->pending - beg); 732 if (val == 0) { 733 s->gzindex = 0; 734 s->status = COMMENT_STATE; 735 } 736 } 737 else 738 s->status = COMMENT_STATE; 739 } 740 if (s->status == COMMENT_STATE) { 741 if (s->gzhead->comment != NULL) { 742 uInt beg = s->pending; /* start of bytes to update crc */ 743 int val; 744 745 do { 746 if (s->pending == s->pending_buf_size) { 747 if (s->gzhead->hcrc && s->pending > beg) 748 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 749 s->pending - beg); 750 flush_pending(strm); 751 beg = s->pending; 752 if (s->pending == s->pending_buf_size) { 753 val = 1; 754 break; 755 } 756 } 757 val = s->gzhead->comment[s->gzindex++]; 758 put_byte(s, val); 759 } while (val != 0); 760 if (s->gzhead->hcrc && s->pending > beg) 761 strm->adler = z_crc32(strm->adler, s->pending_buf + beg, 762 s->pending - beg); 763 if (val == 0) 764 s->status = HCRC_STATE; 765 } 766 else 767 s->status = HCRC_STATE; 768 } 769 if (s->status == HCRC_STATE) { 770 if (s->gzhead->hcrc) { 771 if (s->pending + 2 > s->pending_buf_size) 772 flush_pending(strm); 773 if (s->pending + 2 <= s->pending_buf_size) { 774 put_byte(s, (Byte)(strm->adler & 0xff)); 775 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 776 strm->adler = z_crc32(0L, Z_NULL, 0); 777 s->status = BUSY_STATE; 778 } 779 } 780 else 781 s->status = BUSY_STATE; 782 } 783#endif 784 785 /* Flush as much pending output as possible */ 786 if (s->pending != 0) { 787 flush_pending(strm); 788 if (strm->avail_out == 0) { 789 /* Since avail_out is 0, deflate will be called again with 790 * more output space, but possibly with both pending and 791 * avail_in equal to zero. There won't be anything to do, 792 * but this is not an error situation so make sure we 793 * return OK instead of BUF_ERROR at next call of deflate: 794 */ 795 s->last_flush = -1; 796 return Z_OK; 797 } 798 799 /* Make sure there is something to do and avoid duplicate consecutive 800 * flushes. For repeated and useless calls with Z_FINISH, we keep 801 * returning Z_STREAM_END instead of Z_BUF_ERROR. 802 */ 803 } else if (strm->avail_in == 0 && flush <= old_flush && 804 flush != Z_FINISH) { 805 ERR_RETURN(strm, Z_BUF_ERROR); 806 } 807 808 /* User must not provide more input after the first FINISH: */ 809 if (s->status == FINISH_STATE && strm->avail_in != 0) { 810 ERR_RETURN(strm, Z_BUF_ERROR); 811 } 812 813 /* Start a new block or continue the current one. 814 */ 815 if (strm->avail_in != 0 || s->lookahead != 0 || 816 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 817 block_state bstate; 818 819 bstate = (*(configuration_table[s->level].func))(s, flush); 820 821 if (bstate == finish_started || bstate == finish_done) { 822 s->status = FINISH_STATE; 823 } 824 if (bstate == need_more || bstate == finish_started) { 825 if (strm->avail_out == 0) { 826 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 827 } 828 return Z_OK; 829 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 830 * of deflate should use the same flush parameter to make sure 831 * that the flush is complete. So we don't have to output an 832 * empty block here, this will be done at next call. This also 833 * ensures that for a very small output buffer, we emit at most 834 * one empty block. 835 */ 836 } 837 if (bstate == block_done) { 838 if (flush == Z_PARTIAL_FLUSH) { 839 _tr_align(s); 840 } else { /* FULL_FLUSH or SYNC_FLUSH */ 841 _tr_stored_block(s, (char*)0, 0L, 0); 842 /* For a full flush, this empty block will be recognized 843 * as a special marker by inflate_sync(). 844 */ 845 if (flush == Z_FULL_FLUSH) { 846 CLEAR_HASH(s); /* forget history */ 847 } 848 } 849 flush_pending(strm); 850 if (strm->avail_out == 0) { 851 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 852 return Z_OK; 853 } 854 } 855 } 856 Assert(strm->avail_out > 0, "bug2"); 857 858 if (flush != Z_FINISH) return Z_OK; 859 if (s->wrap <= 0) return Z_STREAM_END; 860 861 /* Write the trailer */ 862#ifdef GZIP 863 if (s->wrap == 2) { 864 put_byte(s, (Byte)(strm->adler & 0xff)); 865 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 866 put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 867 put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 868 put_byte(s, (Byte)(strm->total_in & 0xff)); 869 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 870 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 871 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 872 } 873 else 874#endif 875 { 876 putShortMSB(s, (uInt)(strm->adler >> 16)); 877 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 878 } 879 flush_pending(strm); 880 /* If avail_out is zero, the application will call deflate again 881 * to flush the rest. 882 */ 883 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 884 return s->pending != 0 ? Z_OK : Z_STREAM_END; 885} 886 887/* ========================================================================= */ 888int ZEXPORT deflateEnd (strm) 889 z_streamp strm; 890{ 891 int status; 892 893 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 894 895 status = strm->state->status; 896 if (status != INIT_STATE && 897 status != EXTRA_STATE && 898 status != NAME_STATE && 899 status != COMMENT_STATE && 900 status != HCRC_STATE && 901 status != BUSY_STATE && 902 status != FINISH_STATE) { 903 return Z_STREAM_ERROR; 904 } 905 906 /* Deallocate in reverse order of allocations: */ 907 TRY_FREE(strm, strm->state->pending_buf); 908 TRY_FREE(strm, strm->state->head); 909 TRY_FREE(strm, strm->state->prev); 910 TRY_FREE(strm, strm->state->window); 911 912 ZFREE(strm, strm->state); 913 strm->state = Z_NULL; 914 915 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 916} 917 918/* ========================================================================= 919 * Copy the source state to the destination state. 920 * To simplify the source, this is not supported for 16-bit MSDOS (which 921 * doesn't have enough memory anyway to duplicate compression states). 922 */ 923int ZEXPORT deflateCopy (dest, source) 924 z_streamp dest; 925 z_streamp source; 926{ 927#ifdef MAXSEG_64K 928 return Z_STREAM_ERROR; 929#else 930 deflate_state *ds; 931 deflate_state *ss; 932 ushf *overlay; 933 934 935 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 936 return Z_STREAM_ERROR; 937 } 938 939 ss = source->state; 940 941 zmemcpy(dest, source, sizeof(z_stream)); 942 943 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); 944 if (ds == Z_NULL) return Z_MEM_ERROR; 945 dest->state = (struct internal_state FAR *) ds; 946 zmemcpy(ds, ss, sizeof(deflate_state)); 947 ds->strm = dest; 948 949 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); 950 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); 951 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); 952 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); 953 ds->pending_buf = (uchf *) overlay; 954 955 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || 956 ds->pending_buf == Z_NULL) { 957 deflateEnd (dest); 958 return Z_MEM_ERROR; 959 } 960 /* following zmemcpy do not work for 16-bit MSDOS */ 961 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); 962 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); 963 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); 964 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); 965 966 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); 967 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); 968 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; 969 970 ds->l_desc.dyn_tree = ds->dyn_ltree; 971 ds->d_desc.dyn_tree = ds->dyn_dtree; 972 ds->bl_desc.dyn_tree = ds->bl_tree; 973 974 return Z_OK; 975#endif /* MAXSEG_64K */ 976} 977 978/* =========================================================================== 979 * Read a new buffer from the current input stream, update the adler32 980 * and total number of bytes read. All deflate() input goes through 981 * this function so some applications may wish to modify it to avoid 982 * allocating a large strm->next_in buffer and copying from it. 983 * (See also flush_pending()). 984 */ 985local int read_buf(strm, buf, size) 986 z_streamp strm; 987 Bytef *buf; 988 unsigned size; 989{ 990 unsigned len = strm->avail_in; 991 992 if (len > size) len = size; 993 if (len == 0) return 0; 994 995 strm->avail_in -= len; 996 997 if (strm->state->wrap == 1) { 998 strm->adler = adler32(strm->adler, strm->next_in, len); 999 } 1000#ifdef GZIP 1001 else if (strm->state->wrap == 2) { 1002 strm->adler = z_crc32(strm->adler, strm->next_in, len); 1003 } 1004#endif 1005 zmemcpy(buf, strm->next_in, len); 1006 strm->next_in += len; 1007 strm->total_in += len; 1008 1009 return (int)len; 1010} 1011 1012/* =========================================================================== 1013 * Initialize the "longest match" routines for a new zlib stream 1014 */ 1015local void lm_init (s) 1016 deflate_state *s; 1017{ 1018 s->window_size = (ulg)2L*s->w_size; 1019 1020 CLEAR_HASH(s); 1021 1022 /* Set the default configuration parameters: 1023 */ 1024 s->max_lazy_match = configuration_table[s->level].max_lazy; 1025 s->good_match = configuration_table[s->level].good_length; 1026 s->nice_match = configuration_table[s->level].nice_length; 1027 s->max_chain_length = configuration_table[s->level].max_chain; 1028 1029 s->strstart = 0; 1030 s->block_start = 0L; 1031 s->lookahead = 0; 1032 s->match_length = s->prev_length = MIN_MATCH-1; 1033 s->match_available = 0; 1034 s->ins_h = 0; 1035#ifndef FASTEST 1036#ifdef ASMV 1037 match_init(); /* initialize the asm code */ 1038#endif 1039#endif 1040} 1041 1042#ifndef FASTEST 1043/* =========================================================================== 1044 * Set match_start to the longest match starting at the given string and 1045 * return its length. Matches shorter or equal to prev_length are discarded, 1046 * in which case the result is equal to prev_length and match_start is 1047 * garbage. 1048 * IN assertions: cur_match is the head of the hash chain for the current 1049 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 1050 * OUT assertion: the match length is not greater than s->lookahead. 1051 */ 1052#ifndef ASMV 1053/* For 80x86 and 680x0, an optimized version will be provided in match.asm or 1054 * match.S. The code will be functionally equivalent. 1055 */ 1056local uInt longest_match(s, cur_match) 1057 deflate_state *s; 1058 IPos cur_match; /* current match */ 1059{ 1060 unsigned chain_length = s->max_chain_length;/* max hash chain length */ 1061 register Bytef *scan = s->window + s->strstart; /* current string */ 1062 register Bytef *match; /* matched string */ 1063 register int len; /* length of current match */ 1064 int best_len = s->prev_length; /* best match length so far */ 1065 int nice_match = s->nice_match; /* stop if match long enough */ 1066 IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 1067 s->strstart - (IPos)MAX_DIST(s) : NIL; 1068 /* Stop when cur_match becomes <= limit. To simplify the code, 1069 * we prevent matches with the string of window index 0. 1070 */ 1071 Posf *prev = s->prev; 1072 uInt wmask = s->w_mask; 1073 1074#ifdef UNALIGNED_OK 1075 /* Compare two bytes at a time. Note: this is not always beneficial. 1076 * Try with and without -DUNALIGNED_OK to check. 1077 */ 1078 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; 1079 register ush scan_start = *(ushf*)scan; 1080 register ush scan_end = *(ushf*)(scan+best_len-1); 1081#else 1082 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1083 register Byte scan_end1 = scan[best_len-1]; 1084 register Byte scan_end = scan[best_len]; 1085#endif 1086 1087 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1088 * It is easy to get rid of this optimization if necessary. 1089 */ 1090 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1091 1092 /* Do not waste too much time if we already have a good match: */ 1093 if (s->prev_length >= s->good_match) { 1094 chain_length >>= 2; 1095 } 1096 /* Do not look for matches beyond the end of the input. This is necessary 1097 * to make deflate deterministic. 1098 */ 1099 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 1100 1101 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1102 1103 do { 1104 Assert(cur_match < s->strstart, "no future"); 1105 match = s->window + cur_match; 1106 1107 /* Skip to next match if the match length cannot increase 1108 * or if the match length is less than 2. Note that the checks below 1109 * for insufficient lookahead only occur occasionally for performance 1110 * reasons. Therefore uninitialized memory will be accessed, and 1111 * conditional jumps will be made that depend on those values. 1112 * However the length of the match is limited to the lookahead, so 1113 * the output of deflate is not affected by the uninitialized values. 1114 */ 1115#if (defined(UNALIGNED_OK) && MAX_MATCH == 258) 1116 /* This code assumes sizeof(unsigned short) == 2. Do not use 1117 * UNALIGNED_OK if your compiler uses a different size. 1118 */ 1119 if (*(ushf*)(match+best_len-1) != scan_end || 1120 *(ushf*)match != scan_start) continue; 1121 1122 /* It is not necessary to compare scan[2] and match[2] since they are 1123 * always equal when the other bytes match, given that the hash keys 1124 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at 1125 * strstart+3, +5, ... up to strstart+257. We check for insufficient 1126 * lookahead only every 4th comparison; the 128th check will be made 1127 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is 1128 * necessary to put more guard bytes at the end of the window, or 1129 * to check more often for insufficient lookahead. 1130 */ 1131 Assert(scan[2] == match[2], "scan[2]?"); 1132 scan++, match++; 1133 do { 1134 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1135 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1136 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1137 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1138 scan < strend); 1139 /* The funny "do {}" generates better code on most compilers */ 1140 1141 /* Here, scan <= window+strstart+257 */ 1142 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1143 if (*scan == *match) scan++; 1144 1145 len = (MAX_MATCH - 1) - (int)(strend-scan); 1146 scan = strend - (MAX_MATCH-1); 1147 1148#else /* UNALIGNED_OK */ 1149 1150 if (match[best_len] != scan_end || 1151 match[best_len-1] != scan_end1 || 1152 *match != *scan || 1153 *++match != scan[1]) continue; 1154 1155 /* The check at best_len-1 can be removed because it will be made 1156 * again later. (This heuristic is not always a win.) 1157 * It is not necessary to compare scan[2] and match[2] since they 1158 * are always equal when the other bytes match, given that 1159 * the hash keys are equal and that HASH_BITS >= 8. 1160 */ 1161 scan += 2, match++; 1162 Assert(*scan == *match, "match[2]?"); 1163 1164 /* We check for insufficient lookahead only every 8th comparison; 1165 * the 256th check will be made at strstart+258. 1166 */ 1167 do { 1168 } while (*++scan == *++match && *++scan == *++match && 1169 *++scan == *++match && *++scan == *++match && 1170 *++scan == *++match && *++scan == *++match && 1171 *++scan == *++match && *++scan == *++match && 1172 scan < strend); 1173 1174 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1175 1176 len = MAX_MATCH - (int)(strend - scan); 1177 scan = strend - MAX_MATCH; 1178 1179#endif /* UNALIGNED_OK */ 1180 1181 if (len > best_len) { 1182 s->match_start = cur_match; 1183 best_len = len; 1184 if (len >= nice_match) break; 1185#ifdef UNALIGNED_OK 1186 scan_end = *(ushf*)(scan+best_len-1); 1187#else 1188 scan_end1 = scan[best_len-1]; 1189 scan_end = scan[best_len]; 1190#endif 1191 } 1192 } while ((cur_match = prev[cur_match & wmask]) > limit 1193 && --chain_length != 0); 1194 1195 if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 1196 return s->lookahead; 1197} 1198#endif /* ASMV */ 1199#endif /* FASTEST */ 1200 1201/* --------------------------------------------------------------------------- 1202 * Optimized version for level == 1 or strategy == Z_RLE only 1203 */ 1204local uInt longest_match_fast(s, cur_match) 1205 deflate_state *s; 1206 IPos cur_match; /* current match */ 1207{ 1208 register Bytef *scan = s->window + s->strstart; /* current string */ 1209 register Bytef *match; /* matched string */ 1210 register int len; /* length of current match */ 1211 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1212 1213 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1214 * It is easy to get rid of this optimization if necessary. 1215 */ 1216 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1217 1218 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1219 1220 Assert(cur_match < s->strstart, "no future"); 1221 1222 match = s->window + cur_match; 1223 1224 /* Return failure if the match length is less than 2: 1225 */ 1226 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; 1227 1228 /* The check at best_len-1 can be removed because it will be made 1229 * again later. (This heuristic is not always a win.) 1230 * It is not necessary to compare scan[2] and match[2] since they 1231 * are always equal when the other bytes match, given that 1232 * the hash keys are equal and that HASH_BITS >= 8. 1233 */ 1234 scan += 2, match += 2; 1235 Assert(*scan == *match, "match[2]?"); 1236 1237 /* We check for insufficient lookahead only every 8th comparison; 1238 * the 256th check will be made at strstart+258. 1239 */ 1240 do { 1241 } while (*++scan == *++match && *++scan == *++match && 1242 *++scan == *++match && *++scan == *++match && 1243 *++scan == *++match && *++scan == *++match && 1244 *++scan == *++match && *++scan == *++match && 1245 scan < strend); 1246 1247 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1248 1249 len = MAX_MATCH - (int)(strend - scan); 1250 1251 if (len < MIN_MATCH) return MIN_MATCH - 1; 1252 1253 s->match_start = cur_match; 1254 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; 1255} 1256 1257#ifdef DEBUG 1258/* =========================================================================== 1259 * Check that the match at match_start is indeed a match. 1260 */ 1261local void check_match(s, start, match, length) 1262 deflate_state *s; 1263 IPos start, match; 1264 int length; 1265{ 1266 /* check that the match is indeed a match */ 1267 if (zmemcmp(s->window + match, 1268 s->window + start, length) != EQUAL) { 1269 fprintf(stderr, " start %u, match %u, length %d\n", 1270 start, match, length); 1271 do { 1272 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); 1273 } while (--length != 0); 1274 z_error("invalid match"); 1275 } 1276 if (z_verbose > 1) { 1277 fprintf(stderr,"\\[%d,%d]", start-match, length); 1278 do { putc(s->window[start++], stderr); } while (--length != 0); 1279 } 1280} 1281#else 1282# define check_match(s, start, match, length) 1283#endif /* DEBUG */ 1284 1285/* =========================================================================== 1286 * Fill the window when the lookahead becomes insufficient. 1287 * Updates strstart and lookahead. 1288 * 1289 * IN assertion: lookahead < MIN_LOOKAHEAD 1290 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD 1291 * At least one byte has been read, or avail_in == 0; reads are 1292 * performed for at least two bytes (required for the zip translate_eol 1293 * option -- not supported here). 1294 */ 1295local void fill_window(s) 1296 deflate_state *s; 1297{ 1298 register unsigned n, m; 1299 register Posf *p; 1300 unsigned more; /* Amount of free space at the end of the window. */ 1301 uInt wsize = s->w_size; 1302 1303 do { 1304 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); 1305 1306 /* Deal with !@#$% 64K limit: */ 1307 if (sizeof(int) <= 2) { 1308 if (more == 0 && s->strstart == 0 && s->lookahead == 0) { 1309 more = wsize; 1310 1311 } else if (more == (unsigned)(-1)) { 1312 /* Very unlikely, but possible on 16 bit machine if 1313 * strstart == 0 && lookahead == 1 (input done a byte at time) 1314 */ 1315 more--; 1316 } 1317 } 1318 1319 /* If the window is almost full and there is insufficient lookahead, 1320 * move the upper half to the lower one to make room in the upper half. 1321 */ 1322 if (s->strstart >= wsize+MAX_DIST(s)) { 1323 1324 zmemcpy(s->window, s->window+wsize, (unsigned)wsize); 1325 s->match_start -= wsize; 1326 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ 1327 s->block_start -= (long) wsize; 1328 1329 /* Slide the hash table (could be avoided with 32 bit values 1330 at the expense of memory usage). We slide even when level == 0 1331 to keep the hash table consistent if we switch back to level > 0 1332 later. (Using level 0 permanently is not an optimal usage of 1333 zlib, so we don't care about this pathological case.) 1334 */ 1335 /* %%% avoid this when Z_RLE */ 1336 n = s->hash_size; 1337 p = &s->head[n]; 1338 do { 1339 m = *--p; 1340 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1341 } while (--n); 1342 1343 n = wsize; 1344#ifndef FASTEST 1345 p = &s->prev[n]; 1346 do { 1347 m = *--p; 1348 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1349 /* If n is not on any hash chain, prev[n] is garbage but 1350 * its value will never be used. 1351 */ 1352 } while (--n); 1353#endif 1354 more += wsize; 1355 } 1356 if (s->strm->avail_in == 0) return; 1357 1358 /* If there was no sliding: 1359 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && 1360 * more == window_size - lookahead - strstart 1361 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) 1362 * => more >= window_size - 2*WSIZE + 2 1363 * In the BIG_MEM or MMAP case (not yet supported), 1364 * window_size == input_size + MIN_LOOKAHEAD && 1365 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. 1366 * Otherwise, window_size == 2*WSIZE so more >= 2. 1367 * If there was sliding, more >= WSIZE. So in all cases, more >= 2. 1368 */ 1369 Assert(more >= 2, "more < 2"); 1370 1371 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); 1372 s->lookahead += n; 1373 1374 /* Initialize the hash value now that we have some input: */ 1375 if (s->lookahead >= MIN_MATCH) { 1376 s->ins_h = s->window[s->strstart]; 1377 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1378#if MIN_MATCH != 3 1379 Call UPDATE_HASH() MIN_MATCH-3 more times 1380#endif 1381 } 1382 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, 1383 * but this is not important since only literal bytes will be emitted. 1384 */ 1385 1386 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); 1387} 1388 1389/* =========================================================================== 1390 * Flush the current block, with given end-of-file flag. 1391 * IN assertion: strstart is set to the end of the current match. 1392 */ 1393#define FLUSH_BLOCK_ONLY(s, eof) { \ 1394 _tr_flush_block(s, (s->block_start >= 0L ? \ 1395 (charf *)&s->window[(unsigned)s->block_start] : \ 1396 (charf *)Z_NULL), \ 1397 (ulg)((long)s->strstart - s->block_start), \ 1398 (eof)); \ 1399 s->block_start = s->strstart; \ 1400 flush_pending(s->strm); \ 1401 Tracev((stderr,"[FLUSH]")); \ 1402} 1403 1404/* Same but force premature exit if necessary. */ 1405#define FLUSH_BLOCK(s, eof) { \ 1406 FLUSH_BLOCK_ONLY(s, eof); \ 1407 if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ 1408} 1409 1410/* =========================================================================== 1411 * Copy without compression as much as possible from the input stream, return 1412 * the current block state. 1413 * This function does not insert new strings in the dictionary since 1414 * uncompressible data is probably not useful. This function is used 1415 * only for the level=0 compression option. 1416 * NOTE: this function should be optimized to avoid extra copying from 1417 * window to pending_buf. 1418 */ 1419local block_state deflate_stored(s, flush) 1420 deflate_state *s; 1421 int flush; 1422{ 1423 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited 1424 * to pending_buf_size, and each stored block has a 5 byte header: 1425 */ 1426 ulg max_block_size = 0xffff; 1427 ulg max_start; 1428 1429 if (max_block_size > s->pending_buf_size - 5) { 1430 max_block_size = s->pending_buf_size - 5; 1431 } 1432 1433 /* Copy as much as possible from input to output: */ 1434 for (;;) { 1435 /* Fill the window as much as possible: */ 1436 if (s->lookahead <= 1) { 1437 1438 Assert(s->strstart < s->w_size+MAX_DIST(s) || 1439 s->block_start >= (long)s->w_size, "slide too late"); 1440 1441 fill_window(s); 1442 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; 1443 1444 if (s->lookahead == 0) break; /* flush the current block */ 1445 } 1446 Assert(s->block_start >= 0L, "block gone"); 1447 1448 s->strstart += s->lookahead; 1449 s->lookahead = 0; 1450 1451 /* Emit a stored block if pending_buf will be full: */ 1452 max_start = s->block_start + max_block_size; 1453 if (s->strstart == 0 || (ulg)s->strstart >= max_start) { 1454 /* strstart == 0 is possible when wraparound on 16-bit machine */ 1455 s->lookahead = (uInt)(s->strstart - max_start); 1456 s->strstart = (uInt)max_start; 1457 FLUSH_BLOCK(s, 0); 1458 } 1459 /* Flush if we may have to slide, otherwise block_start may become 1460 * negative and the data will be gone: 1461 */ 1462 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { 1463 FLUSH_BLOCK(s, 0); 1464 } 1465 } 1466 FLUSH_BLOCK(s, flush == Z_FINISH); 1467 return flush == Z_FINISH ? finish_done : block_done; 1468} 1469 1470/* =========================================================================== 1471 * Compress as much as possible from the input stream, return the current 1472 * block state. 1473 * This function does not perform lazy evaluation of matches and inserts 1474 * new strings in the dictionary only for unmatched strings or for short 1475 * matches. It is used only for the fast compression options. 1476 */ 1477local block_state deflate_fast(s, flush) 1478 deflate_state *s; 1479 int flush; 1480{ 1481 IPos hash_head = NIL; /* head of the hash chain */ 1482 int bflush; /* set if current block must be flushed */ 1483 1484 for (;;) { 1485 /* Make sure that we always have enough lookahead, except 1486 * at the end of the input file. We need MAX_MATCH bytes 1487 * for the next match, plus MIN_MATCH bytes to insert the 1488 * string following the next match. 1489 */ 1490 if (s->lookahead < MIN_LOOKAHEAD) { 1491 fill_window(s); 1492 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1493 return need_more; 1494 } 1495 if (s->lookahead == 0) break; /* flush the current block */ 1496 } 1497 1498 /* Insert the string window[strstart .. strstart+2] in the 1499 * dictionary, and set hash_head to the head of the hash chain: 1500 */ 1501 if (s->lookahead >= MIN_MATCH) { 1502 INSERT_STRING(s, s->strstart, hash_head); 1503 } 1504 1505 /* Find the longest match, discarding those <= prev_length. 1506 * At this point we have always match_length < MIN_MATCH 1507 */ 1508 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { 1509 /* To simplify the code, we prevent matches with the string 1510 * of window index 0 (in particular we have to avoid a match 1511 * of the string with itself at the start of the input file). 1512 */ 1513#ifdef FASTEST 1514 if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) || 1515 (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { 1516 s->match_length = longest_match_fast (s, hash_head); 1517 } 1518#else 1519 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { 1520 s->match_length = longest_match (s, hash_head); 1521 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1522 s->match_length = longest_match_fast (s, hash_head); 1523 } 1524#endif 1525 /* longest_match() or longest_match_fast() sets match_start */ 1526 } 1527 if (s->match_length >= MIN_MATCH) { 1528 check_match(s, s->strstart, s->match_start, s->match_length); 1529 1530 _tr_tally_dist(s, s->strstart - s->match_start, 1531 s->match_length - MIN_MATCH, bflush); 1532 1533 s->lookahead -= s->match_length; 1534 1535 /* Insert new strings in the hash table only if the match length 1536 * is not too large. This saves time but degrades compression. 1537 */ 1538#ifndef FASTEST 1539 if (s->match_length <= s->max_insert_length && 1540 s->lookahead >= MIN_MATCH) { 1541 s->match_length--; /* string at strstart already in table */ 1542 do { 1543 s->strstart++; 1544 INSERT_STRING(s, s->strstart, hash_head); 1545 /* strstart never exceeds WSIZE-MAX_MATCH, so there are 1546 * always MIN_MATCH bytes ahead. 1547 */ 1548 } while (--s->match_length != 0); 1549 s->strstart++; 1550 } else 1551#endif 1552 { 1553 s->strstart += s->match_length; 1554 s->match_length = 0; 1555 s->ins_h = s->window[s->strstart]; 1556 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1557#if MIN_MATCH != 3 1558 Call UPDATE_HASH() MIN_MATCH-3 more times 1559#endif 1560 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not 1561 * matter since it will be recomputed at next deflate call. 1562 */ 1563 } 1564 } else { 1565 /* No match, output a literal byte */ 1566 Tracevv((stderr,"%c", s->window[s->strstart])); 1567 _tr_tally_lit (s, s->window[s->strstart], bflush); 1568 s->lookahead--; 1569 s->strstart++; 1570 } 1571 if (bflush) FLUSH_BLOCK(s, 0); 1572 } 1573 FLUSH_BLOCK(s, flush == Z_FINISH); 1574 return flush == Z_FINISH ? finish_done : block_done; 1575} 1576 1577#ifndef FASTEST 1578/* =========================================================================== 1579 * Same as above, but achieves better compression. We use a lazy 1580 * evaluation for matches: a match is finally adopted only if there is 1581 * no better match at the next window position. 1582 */ 1583local block_state deflate_slow(s, flush) 1584 deflate_state *s; 1585 int flush; 1586{ 1587 IPos hash_head = NIL; /* head of hash chain */ 1588 int bflush; /* set if current block must be flushed */ 1589 1590 /* Process the input block. */ 1591 for (;;) { 1592 /* Make sure that we always have enough lookahead, except 1593 * at the end of the input file. We need MAX_MATCH bytes 1594 * for the next match, plus MIN_MATCH bytes to insert the 1595 * string following the next match. 1596 */ 1597 if (s->lookahead < MIN_LOOKAHEAD) { 1598 fill_window(s); 1599 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1600 return need_more; 1601 } 1602 if (s->lookahead == 0) break; /* flush the current block */ 1603 } 1604 1605 /* Insert the string window[strstart .. strstart+2] in the 1606 * dictionary, and set hash_head to the head of the hash chain: 1607 */ 1608 if (s->lookahead >= MIN_MATCH) { 1609 INSERT_STRING(s, s->strstart, hash_head); 1610 } 1611 1612 /* Find the longest match, discarding those <= prev_length. 1613 */ 1614 s->prev_length = s->match_length, s->prev_match = s->match_start; 1615 s->match_length = MIN_MATCH-1; 1616 1617 if (hash_head != NIL && s->prev_length < s->max_lazy_match && 1618 s->strstart - hash_head <= MAX_DIST(s)) { 1619 /* To simplify the code, we prevent matches with the string 1620 * of window index 0 (in particular we have to avoid a match 1621 * of the string with itself at the start of the input file). 1622 */ 1623 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { 1624 s->match_length = longest_match (s, hash_head); 1625 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1626 s->match_length = longest_match_fast (s, hash_head); 1627 } 1628 /* longest_match() or longest_match_fast() sets match_start */ 1629 1630 if (s->match_length <= 5 && (s->strategy == Z_FILTERED 1631#if TOO_FAR <= 32767 1632 || (s->match_length == MIN_MATCH && 1633 s->strstart - s->match_start > TOO_FAR) 1634#endif 1635 )) { 1636 1637 /* If prev_match is also MIN_MATCH, match_start is garbage 1638 * but we will ignore the current match anyway. 1639 */ 1640 s->match_length = MIN_MATCH-1; 1641 } 1642 } 1643 /* If there was a match at the previous step and the current 1644 * match is not better, output the previous match: 1645 */ 1646 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { 1647 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; 1648 /* Do not insert strings in hash table beyond this. */ 1649 1650 check_match(s, s->strstart-1, s->prev_match, s->prev_length); 1651 1652 _tr_tally_dist(s, s->strstart -1 - s->prev_match, 1653 s->prev_length - MIN_MATCH, bflush); 1654 1655 /* Insert in hash table all strings up to the end of the match. 1656 * strstart-1 and strstart are already inserted. If there is not 1657 * enough lookahead, the last two strings are not inserted in 1658 * the hash table. 1659 */ 1660 s->lookahead -= s->prev_length-1; 1661 s->prev_length -= 2; 1662 do { 1663 if (++s->strstart <= max_insert) { 1664 INSERT_STRING(s, s->strstart, hash_head); 1665 } 1666 } while (--s->prev_length != 0); 1667 s->match_available = 0; 1668 s->match_length = MIN_MATCH-1; 1669 s->strstart++; 1670 1671 if (bflush) FLUSH_BLOCK(s, 0); 1672 1673 } else if (s->match_available) { 1674 /* If there was no match at the previous position, output a 1675 * single literal. If there was a match but the current match 1676 * is longer, truncate the previous match to a single literal. 1677 */ 1678 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1679 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1680 if (bflush) { 1681 FLUSH_BLOCK_ONLY(s, 0); 1682 } 1683 s->strstart++; 1684 s->lookahead--; 1685 if (s->strm->avail_out == 0) return need_more; 1686 } else { 1687 /* There is no previous match to compare with, wait for 1688 * the next step to decide. 1689 */ 1690 s->match_available = 1; 1691 s->strstart++; 1692 s->lookahead--; 1693 } 1694 } 1695 Assert (flush != Z_NO_FLUSH, "no flush?"); 1696 if (s->match_available) { 1697 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1698 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1699 s->match_available = 0; 1700 } 1701 FLUSH_BLOCK(s, flush == Z_FINISH); 1702 return flush == Z_FINISH ? finish_done : block_done; 1703} 1704#endif /* FASTEST */ 1705 1706#if 0 1707/* =========================================================================== 1708 * For Z_RLE, simply look for runs of bytes, generate matches only of distance 1709 * one. Do not maintain a hash table. (It will be regenerated if this run of 1710 * deflate switches away from Z_RLE.) 1711 */ 1712local block_state deflate_rle(s, flush) 1713 deflate_state *s; 1714 int flush; 1715{ 1716 int bflush; /* set if current block must be flushed */ 1717 uInt run; /* length of run */ 1718 uInt max; /* maximum length of run */ 1719 uInt prev; /* byte at distance one to match */ 1720 Bytef *scan; /* scan for end of run */ 1721 1722 for (;;) { 1723 /* Make sure that we always have enough lookahead, except 1724 * at the end of the input file. We need MAX_MATCH bytes 1725 * for the longest encodable run. 1726 */ 1727 if (s->lookahead < MAX_MATCH) { 1728 fill_window(s); 1729 if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { 1730 return need_more; 1731 } 1732 if (s->lookahead == 0) break; /* flush the current block */ 1733 } 1734 1735 /* See how many times the previous byte repeats */ 1736 run = 0; 1737 if (s->strstart > 0) { /* if there is a previous byte, that is */ 1738 max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH; 1739 scan = s->window + s->strstart - 1; 1740 prev = *scan++; 1741 do { 1742 if (*scan++ != prev) 1743 break; 1744 } while (++run < max); 1745 } 1746 1747 /* Emit match if have run of MIN_MATCH or longer, else emit literal */ 1748 if (run >= MIN_MATCH) { 1749 check_match(s, s->strstart, s->strstart - 1, run); 1750 _tr_tally_dist(s, 1, run - MIN_MATCH, bflush); 1751 s->lookahead -= run; 1752 s->strstart += run; 1753 } else { 1754 /* No match, output a literal byte */ 1755 Tracevv((stderr,"%c", s->window[s->strstart])); 1756 _tr_tally_lit (s, s->window[s->strstart], bflush); 1757 s->lookahead--; 1758 s->strstart++; 1759 } 1760 if (bflush) FLUSH_BLOCK(s, 0); 1761 } 1762 FLUSH_BLOCK(s, flush == Z_FINISH); 1763 return flush == Z_FINISH ? finish_done : block_done; 1764} 1765#endif 1766