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 (s->status == FINISH_STATE && flush != Z_FINISH) { 596 ERR_RETURN(strm, Z_STREAM_ERROR); 597 } 598 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 599 600 s->strm = strm; /* just in case */ 601 old_flush = s->last_flush; 602 s->last_flush = flush; 603 604 /* Write the header */ 605 if (s->status == INIT_STATE) { 606 #ifdef GZIP 607 if (s->wrap == 2) { 608 strm->adler = crc32(0L, Z_NULL, 0); 609 put_byte(s, 31); 610 put_byte(s, 139); 611 put_byte(s, 8); 612 if (s->gzhead == Z_NULL) { 613 put_byte(s, 0); 614 put_byte(s, 0); 615 put_byte(s, 0); 616 put_byte(s, 0); 617 put_byte(s, 0); 618 put_byte(s, s->level == 9 ? 2 : 619 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 620 4 : 0)); 621 put_byte(s, OS_CODE); 622 s->status = BUSY_STATE; 623 } 624 else { 625 put_byte(s, (s->gzhead->text ? 1 : 0) + 626 (s->gzhead->hcrc ? 2 : 0) + 627 (s->gzhead->extra == Z_NULL ? 0 : 4) + 628 (s->gzhead->name == Z_NULL ? 0 : 8) + 629 (s->gzhead->comment == Z_NULL ? 0 : 16) 630 ); 631 put_byte(s, (Byte)(s->gzhead->time & 0xff)); 632 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); 633 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); 634 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); 635 put_byte(s, s->level == 9 ? 2 : 636 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 637 4 : 0)); 638 put_byte(s, s->gzhead->os & 0xff); 639 if (s->gzhead->extra != Z_NULL) { 640 put_byte(s, s->gzhead->extra_len & 0xff); 641 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); 642 } 643 if (s->gzhead->hcrc) 644 strm->adler = crc32(strm->adler, s->pending_buf, 645 s->pending); 646 s->gzindex = 0; 647 s->status = EXTRA_STATE; 648 } 649 } 650 else 651 #endif 652 { 653 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 654 uInt level_flags; 655 656 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 657 level_flags = 0; 658 else if (s->level < 6) 659 level_flags = 1; 660 else if (s->level == 6) 661 level_flags = 2; 662 else 663 level_flags = 3; 664 header |= (level_flags << 6); 665 if (s->strstart != 0) header |= PRESET_DICT; 666 header += 31 - (header % 31); 667 668 s->status = BUSY_STATE; 669 putShortMSB(s, header); 670 671 /* Save the adler32 of the preset dictionary: */ 672 if (s->strstart != 0) { 673 putShortMSB(s, (uInt)(strm->adler >> 16)); 674 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 675 } 676 strm->adler = adler32(0L, Z_NULL, 0); 677 } 678 } 679 #ifdef GZIP 680 if (s->status == EXTRA_STATE) { 681 if (s->gzhead->extra != Z_NULL) { 682 uInt beg = s->pending; /* start of bytes to update crc */ 683 684 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { 685 if (s->pending == s->pending_buf_size) { 686 if (s->gzhead->hcrc && s->pending > beg) 687 strm->adler = crc32(strm->adler, s->pending_buf + beg, 688 s->pending - beg); 689 flush_pending(strm); 690 beg = s->pending; 691 if (s->pending == s->pending_buf_size) 692 break; 693 } 694 put_byte(s, s->gzhead->extra[s->gzindex]); 695 s->gzindex++; 696 } 697 if (s->gzhead->hcrc && s->pending > beg) 698 strm->adler = crc32(strm->adler, s->pending_buf + beg, 699 s->pending - beg); 700 if (s->gzindex == s->gzhead->extra_len) { 701 s->gzindex = 0; 702 s->status = NAME_STATE; 703 } 704 } 705 else 706 s->status = NAME_STATE; 707 } 708 if (s->status == NAME_STATE) { 709 if (s->gzhead->name != Z_NULL) { 710 uInt beg = s->pending; /* start of bytes to update crc */ 711 int val; 712 713 do { 714 if (s->pending == s->pending_buf_size) { 715 if (s->gzhead->hcrc && s->pending > beg) 716 strm->adler = crc32(strm->adler, s->pending_buf + beg, 717 s->pending - beg); 718 flush_pending(strm); 719 beg = s->pending; 720 if (s->pending == s->pending_buf_size) { 721 val = 1; 722 break; 723 } 724 } 725 val = s->gzhead->name[s->gzindex++]; 726 put_byte(s, val); 727 } while (val != 0); 728 if (s->gzhead->hcrc && s->pending > beg) 729 strm->adler = crc32(strm->adler, s->pending_buf + beg, 730 s->pending - beg); 731 if (val == 0) { 732 s->gzindex = 0; 733 s->status = COMMENT_STATE; 734 } 735 } 736 else 737 s->status = COMMENT_STATE; 738 } 739 if (s->status == COMMENT_STATE) { 740 if (s->gzhead->comment != Z_NULL) { 741 uInt beg = s->pending; /* start of bytes to update crc */ 742 int val; 743 744 do { 745 if (s->pending == s->pending_buf_size) { 746 if (s->gzhead->hcrc && s->pending > beg) 747 strm->adler = crc32(strm->adler, s->pending_buf + beg, 748 s->pending - beg); 749 flush_pending(strm); 750 beg = s->pending; 751 if (s->pending == s->pending_buf_size) { 752 val = 1; 753 break; 754 } 755 } 756 val = s->gzhead->comment[s->gzindex++]; 757 put_byte(s, val); 758 } while (val != 0); 759 if (s->gzhead->hcrc && s->pending > beg) 760 strm->adler = crc32(strm->adler, s->pending_buf + beg, 761 s->pending - beg); 762 if (val == 0) 763 s->status = HCRC_STATE; 764 } 765 else 766 s->status = HCRC_STATE; 767 } 768 if (s->status == HCRC_STATE) { 769 if (s->gzhead->hcrc) { 770 if (s->pending + 2 > s->pending_buf_size) 771 flush_pending(strm); 772 if (s->pending + 2 <= s->pending_buf_size) { 773 put_byte(s, (Byte)(strm->adler & 0xff)); 774 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 775 strm->adler = crc32(0L, Z_NULL, 0); 776 s->status = BUSY_STATE; 777 } 778 } 779 else 780 s->status = BUSY_STATE; 781 } 782 #endif 783 784 /* Flush as much pending output as possible */ 785 if (s->pending != 0) { 786 flush_pending(strm); 787 if (strm->avail_out == 0) { 788 /* Since avail_out is 0, deflate will be called again with 789 * more output space, but possibly with both pending and 790 * avail_in equal to zero. There won't be anything to do, 791 * but this is not an error situation so make sure we 792 * return OK instead of BUF_ERROR at next call of deflate: 793 */ 794 s->last_flush = -1; 795 return Z_OK; 796 } 797 798 /* Make sure there is something to do and avoid duplicate consecutive 799 * flushes. For repeated and useless calls with Z_FINISH, we keep 800 * returning Z_STREAM_END instead of Z_BUF_ERROR. 801 */ 802 } else if (strm->avail_in == 0 && flush <= old_flush && 803 flush != Z_FINISH) { 804 ERR_RETURN(strm, Z_BUF_ERROR); 805 } 806 807 /* User must not provide more input after the first FINISH: */ 808 if (s->status == FINISH_STATE && strm->avail_in != 0) { 809 ERR_RETURN(strm, Z_BUF_ERROR); 810 } 811 812 /* Start a new block or continue the current one. 813 */ 814 if (strm->avail_in != 0 || s->lookahead != 0 || 815 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 816 block_state bstate; 817 818 bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : 819 (s->strategy == Z_RLE ? deflate_rle(s, flush) : 820 (*(configuration_table[s->level].func))(s, flush)); 821 822 if (bstate == finish_started || bstate == finish_done) { 823 s->status = FINISH_STATE; 824 } 825 if (bstate == need_more || bstate == finish_started) { 826 if (strm->avail_out == 0) { 827 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 828 } 829 return Z_OK; 830 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 831 * of deflate should use the same flush parameter to make sure 832 * that the flush is complete. So we don't have to output an 833 * empty block here, this will be done at next call. This also 834 * ensures that for a very small output buffer, we emit at most 835 * one empty block. 836 */ 837 } 838 if (bstate == block_done) { 839 if (flush == Z_PARTIAL_FLUSH) { 840 _tr_align(s); 841 } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ 842 _tr_stored_block(s, (char*)0, 0L, 0); 843 /* For a full flush, this empty block will be recognized 844 * as a special marker by inflate_sync(). 845 */ 846 if (flush == Z_FULL_FLUSH) { 847 CLEAR_HASH(s); /* forget history */ 848 if (s->lookahead == 0) { 849 s->strstart = 0; 850 s->block_start = 0L; 851 } 852 } 853 } 854 flush_pending(strm); 855 if (strm->avail_out == 0) { 856 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 857 return Z_OK; 858 } 859 } 860 } 861 Assert(strm->avail_out > 0, "bug2"); 862 863 if (flush != Z_FINISH) return Z_OK; 864 if (s->wrap <= 0) return Z_STREAM_END; 865 866 /* Write the trailer */ 867 #ifdef GZIP 868 if (s->wrap == 2) { 869 put_byte(s, (Byte)(strm->adler & 0xff)); 870 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 871 put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 872 put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 873 put_byte(s, (Byte)(strm->total_in & 0xff)); 874 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 875 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 876 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 877 } 878 else 879 #endif 880 { 881 putShortMSB(s, (uInt)(strm->adler >> 16)); 882 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 883 } 884 flush_pending(strm); 885 /* If avail_out is zero, the application will call deflate again 886 * to flush the rest. 887 */ 888 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 889 return s->pending != 0 ? Z_OK : Z_STREAM_END; 890 } 891 892 /* ========================================================================= */ 893 int ZEXPORT deflateEnd (strm) 894 z_streamp strm; 895 { 896 int status; 897 898 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 899 900 status = strm->state->status; 901 if (status != INIT_STATE && 902 status != EXTRA_STATE && 903 status != NAME_STATE && 904 status != COMMENT_STATE && 905 status != HCRC_STATE && 906 status != BUSY_STATE && 907 status != FINISH_STATE) { 908 return Z_STREAM_ERROR; 909 } 910 911 /* Deallocate in reverse order of allocations: */ 912 TRY_FREE(strm, strm->state->pending_buf); 913 TRY_FREE(strm, strm->state->head); 914 TRY_FREE(strm, strm->state->prev); 915 TRY_FREE(strm, strm->state->window); 916 917 ZFREE(strm, strm->state); 918 strm->state = Z_NULL; 919 920 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 921 } 922 923 /* ========================================================================= 924 * Copy the source state to the destination state. 925 * To simplify the source, this is not supported for 16-bit MSDOS (which 926 * doesn't have enough memory anyway to duplicate compression states). 927 */ 928 int ZEXPORT deflateCopy (dest, source) 929 z_streamp dest; 930 z_streamp source; 931 { 932 #ifdef MAXSEG_64K 933 return Z_STREAM_ERROR; 934 #else 935 deflate_state *ds; 936 deflate_state *ss; 937 ushf *overlay; 938 939 940 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 941 return Z_STREAM_ERROR; 942 } 943 944 ss = source->state; 945 946 zmemcpy(dest, source, sizeof(z_stream)); 947 948 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); 949 if (ds == Z_NULL) return Z_MEM_ERROR; 950 dest->state = (struct internal_state FAR *) ds; 951 zmemcpy(ds, ss, sizeof(deflate_state)); 952 ds->strm = dest; 953 954 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); 955 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); 956 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); 957 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); 958 ds->pending_buf = (uchf *) overlay; 959 960 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || 961 ds->pending_buf == Z_NULL) { 962 deflateEnd (dest); 963 return Z_MEM_ERROR; 964 } 965 /* following zmemcpy do not work for 16-bit MSDOS */ 966 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); 967 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); 968 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); 969 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); 970 971 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); 972 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); 973 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; 974 975 ds->l_desc.dyn_tree = ds->dyn_ltree; 976 ds->d_desc.dyn_tree = ds->dyn_dtree; 977 ds->bl_desc.dyn_tree = ds->bl_tree; 978 979 return Z_OK; 980 #endif /* MAXSEG_64K */ 981 } 982 983 /* =========================================================================== 984 * Read a new buffer from the current input stream, update the adler32 985 * and total number of bytes read. All deflate() input goes through 986 * this function so some applications may wish to modify it to avoid 987 * allocating a large strm->next_in buffer and copying from it. 988 * (See also flush_pending()). 989 */ 990 local int read_buf(strm, buf, size) 991 z_streamp strm; 992 Bytef *buf; 993 unsigned size; 994 { 995 unsigned len = strm->avail_in; 996 997 if (len > size) len = size; 998 if (len == 0) return 0; 999 1000 strm->avail_in -= len; 1001 1002 if (strm->state->wrap == 1) { 1003 strm->adler = adler32(strm->adler, strm->next_in, len); 1004 } 1005 #ifdef GZIP 1006 else if (strm->state->wrap == 2) { 1007 strm->adler = crc32(strm->adler, strm->next_in, len); 1008 } 1009 #endif 1010 zmemcpy(buf, strm->next_in, len); 1011 strm->next_in += len; 1012 strm->total_in += len; 1013 1014 return (int)len; 1015 } 1016 1017 /* =========================================================================== 1018 * Initialize the "longest match" routines for a new zlib stream 1019 */ 1020 local void lm_init (s) 1021 deflate_state *s; 1022 { 1023 s->window_size = (ulg)2L*s->w_size; 1024 1025 CLEAR_HASH(s); 1026 1027 /* Set the default configuration parameters: 1028 */ 1029 s->max_lazy_match = configuration_table[s->level].max_lazy; 1030 s->good_match = configuration_table[s->level].good_length; 1031 s->nice_match = configuration_table[s->level].nice_length; 1032 s->max_chain_length = configuration_table[s->level].max_chain; 1033 1034 s->strstart = 0; 1035 s->block_start = 0L; 1036 s->lookahead = 0; 1037 s->match_length = s->prev_length = MIN_MATCH-1; 1038 s->match_available = 0; 1039 s->ins_h = 0; 1040 #ifndef FASTEST 1041 #ifdef ASMV 1042 match_init(); /* initialize the asm code */ 1043 #endif 1044 #endif 1045 } 1046 1047 #ifndef FASTEST 1048 /* =========================================================================== 1049 * Set match_start to the longest match starting at the given string and 1050 * return its length. Matches shorter or equal to prev_length are discarded, 1051 * in which case the result is equal to prev_length and match_start is 1052 * garbage. 1053 * IN assertions: cur_match is the head of the hash chain for the current 1054 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 1055 * OUT assertion: the match length is not greater than s->lookahead. 1056 */ 1057 #ifndef ASMV 1058 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or 1059 * match.S. The code will be functionally equivalent. 1060 */ 1061 local uInt longest_match(s, cur_match) 1062 deflate_state *s; 1063 IPos cur_match; /* current match */ 1064 { 1065 unsigned chain_length = s->max_chain_length;/* max hash chain length */ 1066 register Bytef *scan = s->window + s->strstart; /* current string */ 1067 register Bytef *match; /* matched string */ 1068 register int len; /* length of current match */ 1069 int best_len = s->prev_length; /* best match length so far */ 1070 int nice_match = s->nice_match; /* stop if match long enough */ 1071 IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 1072 s->strstart - (IPos)MAX_DIST(s) : NIL; 1073 /* Stop when cur_match becomes <= limit. To simplify the code, 1074 * we prevent matches with the string of window index 0. 1075 */ 1076 Posf *prev = s->prev; 1077 uInt wmask = s->w_mask; 1078 1079 #ifdef UNALIGNED_OK 1080 /* Compare two bytes at a time. Note: this is not always beneficial. 1081 * Try with and without -DUNALIGNED_OK to check. 1082 */ 1083 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; 1084 register ush scan_start = *(ushf*)scan; 1085 register ush scan_end = *(ushf*)(scan+best_len-1); 1086 #else 1087 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1088 register Byte scan_end1 = scan[best_len-1]; 1089 register Byte scan_end = scan[best_len]; 1090 #endif 1091 1092 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1093 * It is easy to get rid of this optimization if necessary. 1094 */ 1095 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1096 1097 /* Do not waste too much time if we already have a good match: */ 1098 if (s->prev_length >= s->good_match) { 1099 chain_length >>= 2; 1100 } 1101 /* Do not look for matches beyond the end of the input. This is necessary 1102 * to make deflate deterministic. 1103 */ 1104 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 1105 1106 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1107 1108 do { 1109 Assert(cur_match < s->strstart, "no future"); 1110 match = s->window + cur_match; 1111 1112 /* Skip to next match if the match length cannot increase 1113 * or if the match length is less than 2. Note that the checks below 1114 * for insufficient lookahead only occur occasionally for performance 1115 * reasons. Therefore uninitialized memory will be accessed, and 1116 * conditional jumps will be made that depend on those values. 1117 * However the length of the match is limited to the lookahead, so 1118 * the output of deflate is not affected by the uninitialized values. 1119 */ 1120 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) 1121 /* This code assumes sizeof(unsigned short) == 2. Do not use 1122 * UNALIGNED_OK if your compiler uses a different size. 1123 */ 1124 if (*(ushf*)(match+best_len-1) != scan_end || 1125 *(ushf*)match != scan_start) continue; 1126 1127 /* It is not necessary to compare scan[2] and match[2] since they are 1128 * always equal when the other bytes match, given that the hash keys 1129 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at 1130 * strstart+3, +5, ... up to strstart+257. We check for insufficient 1131 * lookahead only every 4th comparison; the 128th check will be made 1132 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is 1133 * necessary to put more guard bytes at the end of the window, or 1134 * to check more often for insufficient lookahead. 1135 */ 1136 Assert(scan[2] == match[2], "scan[2]?"); 1137 scan++, match++; 1138 do { 1139 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1140 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1141 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1142 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1143 scan < strend); 1144 /* The funny "do {}" generates better code on most compilers */ 1145 1146 /* Here, scan <= window+strstart+257 */ 1147 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1148 if (*scan == *match) scan++; 1149 1150 len = (MAX_MATCH - 1) - (int)(strend-scan); 1151 scan = strend - (MAX_MATCH-1); 1152 1153 #else /* UNALIGNED_OK */ 1154 1155 if (match[best_len] != scan_end || 1156 match[best_len-1] != scan_end1 || 1157 *match != *scan || 1158 *++match != scan[1]) continue; 1159 1160 /* The check at best_len-1 can be removed because it will be made 1161 * again later. (This heuristic is not always a win.) 1162 * It is not necessary to compare scan[2] and match[2] since they 1163 * are always equal when the other bytes match, given that 1164 * the hash keys are equal and that HASH_BITS >= 8. 1165 */ 1166 scan += 2, match++; 1167 Assert(*scan == *match, "match[2]?"); 1168 1169 /* We check for insufficient lookahead only every 8th comparison; 1170 * the 256th check will be made at strstart+258. 1171 */ 1172 do { 1173 } while (*++scan == *++match && *++scan == *++match && 1174 *++scan == *++match && *++scan == *++match && 1175 *++scan == *++match && *++scan == *++match && 1176 *++scan == *++match && *++scan == *++match && 1177 scan < strend); 1178 1179 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1180 1181 len = MAX_MATCH - (int)(strend - scan); 1182 scan = strend - MAX_MATCH; 1183 1184 #endif /* UNALIGNED_OK */ 1185 1186 if (len > best_len) { 1187 s->match_start = cur_match; 1188 best_len = len; 1189 if (len >= nice_match) break; 1190 #ifdef UNALIGNED_OK 1191 scan_end = *(ushf*)(scan+best_len-1); 1192 #else 1193 scan_end1 = scan[best_len-1]; 1194 scan_end = scan[best_len]; 1195 #endif 1196 } 1197 } while ((cur_match = prev[cur_match & wmask]) > limit 1198 && --chain_length != 0); 1199 1200 if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 1201 return s->lookahead; 1202 } 1203 #endif /* ASMV */ 1204 1205 #else /* FASTEST */ 1206 1207 /* --------------------------------------------------------------------------- 1208 * Optimized version for FASTEST only 1209 */ 1210 local uInt longest_match(s, cur_match) 1211 deflate_state *s; 1212 IPos cur_match; /* current match */ 1213 { 1214 register Bytef *scan = s->window + s->strstart; /* current string */ 1215 register Bytef *match; /* matched string */ 1216 register int len; /* length of current match */ 1217 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1218 1219 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1220 * It is easy to get rid of this optimization if necessary. 1221 */ 1222 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1223 1224 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1225 1226 Assert(cur_match < s->strstart, "no future"); 1227 1228 match = s->window + cur_match; 1229 1230 /* Return failure if the match length is less than 2: 1231 */ 1232 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; 1233 1234 /* The check at best_len-1 can be removed because it will be made 1235 * again later. (This heuristic is not always a win.) 1236 * It is not necessary to compare scan[2] and match[2] since they 1237 * are always equal when the other bytes match, given that 1238 * the hash keys are equal and that HASH_BITS >= 8. 1239 */ 1240 scan += 2, match += 2; 1241 Assert(*scan == *match, "match[2]?"); 1242 1243 /* We check for insufficient lookahead only every 8th comparison; 1244 * the 256th check will be made at strstart+258. 1245 */ 1246 do { 1247 } while (*++scan == *++match && *++scan == *++match && 1248 *++scan == *++match && *++scan == *++match && 1249 *++scan == *++match && *++scan == *++match && 1250 *++scan == *++match && *++scan == *++match && 1251 scan < strend); 1252 1253 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1254 1255 len = MAX_MATCH - (int)(strend - scan); 1256 1257 if (len < MIN_MATCH) return MIN_MATCH - 1; 1258 1259 s->match_start = cur_match; 1260 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; 1261 } 1262 1263 #endif /* FASTEST */ 1264 1265 #ifdef DEBUG 1266 /* =========================================================================== 1267 * Check that the match at match_start is indeed a match. 1268 */ 1269 local void check_match(s, start, match, length) 1270 deflate_state *s; 1271 IPos start, match; 1272 int length; 1273 { 1274 /* check that the match is indeed a match */ 1275 if (zmemcmp(s->window + match, 1276 s->window + start, length) != EQUAL) { 1277 fprintf(stderr, " start %u, match %u, length %d\n", 1278 start, match, length); 1279 do { 1280 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); 1281 } while (--length != 0); 1282 z_error("invalid match"); 1283 } 1284 if (z_verbose > 1) { 1285 fprintf(stderr,"\\[%d,%d]", start-match, length); 1286 do { putc(s->window[start++], stderr); } while (--length != 0); 1287 } 1288 } 1289 #else 1290 # define check_match(s, start, match, length) 1291 #endif /* DEBUG */ 1292 1293 /* =========================================================================== 1294 * Fill the window when the lookahead becomes insufficient. 1295 * Updates strstart and lookahead. 1296 * 1297 * IN assertion: lookahead < MIN_LOOKAHEAD 1298 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD 1299 * At least one byte has been read, or avail_in == 0; reads are 1300 * performed for at least two bytes (required for the zip translate_eol 1301 * option -- not supported here). 1302 */ 1303 local void fill_window(s) 1304 deflate_state *s; 1305 { 1306 register unsigned n, m; 1307 register Posf *p; 1308 unsigned more; /* Amount of free space at the end of the window. */ 1309 uInt wsize = s->w_size; 1310 1311 do { 1312 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); 1313 1314 /* Deal with !@#$% 64K limit: */ 1315 if (sizeof(int) <= 2) { 1316 if (more == 0 && s->strstart == 0 && s->lookahead == 0) { 1317 more = wsize; 1318 1319 } else if (more == (unsigned)(-1)) { 1320 /* Very unlikely, but possible on 16 bit machine if 1321 * strstart == 0 && lookahead == 1 (input done a byte at time) 1322 */ 1323 more--; 1324 } 1325 } 1326 1327 /* If the window is almost full and there is insufficient lookahead, 1328 * move the upper half to the lower one to make room in the upper half. 1329 */ 1330 if (s->strstart >= wsize+MAX_DIST(s)) { 1331 1332 zmemcpy(s->window, s->window+wsize, (unsigned)wsize); 1333 s->match_start -= wsize; 1334 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ 1335 s->block_start -= (long) wsize; 1336 1337 /* Slide the hash table (could be avoided with 32 bit values 1338 at the expense of memory usage). We slide even when level == 0 1339 to keep the hash table consistent if we switch back to level > 0 1340 later. (Using level 0 permanently is not an optimal usage of 1341 zlib, so we don't care about this pathological case.) 1342 */ 1343 n = s->hash_size; 1344 p = &s->head[n]; 1345 do { 1346 m = *--p; 1347 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1348 } while (--n); 1349 1350 n = wsize; 1351 #ifndef FASTEST 1352 p = &s->prev[n]; 1353 do { 1354 m = *--p; 1355 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1356 /* If n is not on any hash chain, prev[n] is garbage but 1357 * its value will never be used. 1358 */ 1359 } while (--n); 1360 #endif 1361 more += wsize; 1362 } 1363 if (s->strm->avail_in == 0) return; 1364 1365 /* If there was no sliding: 1366 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && 1367 * more == window_size - lookahead - strstart 1368 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) 1369 * => more >= window_size - 2*WSIZE + 2 1370 * In the BIG_MEM or MMAP case (not yet supported), 1371 * window_size == input_size + MIN_LOOKAHEAD && 1372 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. 1373 * Otherwise, window_size == 2*WSIZE so more >= 2. 1374 * If there was sliding, more >= WSIZE. So in all cases, more >= 2. 1375 */ 1376 Assert(more >= 2, "more < 2"); 1377 1378 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); 1379 s->lookahead += n; 1380 1381 /* Initialize the hash value now that we have some input: */ 1382 if (s->lookahead >= MIN_MATCH) { 1383 s->ins_h = s->window[s->strstart]; 1384 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1385 #if MIN_MATCH != 3 1386 Call UPDATE_HASH() MIN_MATCH-3 more times 1387 #endif 1388 } 1389 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, 1390 * but this is not important since only literal bytes will be emitted. 1391 */ 1392 1393 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); 1394 1395 /* If the WIN_INIT bytes after the end of the current data have never been 1396 * written, then zero those bytes in order to avoid memory check reports of 1397 * the use of uninitialized (or uninitialised as Julian writes) bytes by 1398 * the longest match routines. Update the high water mark for the next 1399 * time through here. WIN_INIT is set to MAX_MATCH since the longest match 1400 * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. 1401 */ 1402 if (s->high_water < s->window_size) { 1403 ulg curr = s->strstart + (ulg)(s->lookahead); 1404 ulg init; 1405 1406 if (s->high_water < curr) { 1407 /* Previous high water mark below current data -- zero WIN_INIT 1408 * bytes or up to end of window, whichever is less. 1409 */ 1410 init = s->window_size - curr; 1411 if (init > WIN_INIT) 1412 init = WIN_INIT; 1413 zmemzero(s->window + curr, (unsigned)init); 1414 s->high_water = curr + init; 1415 } 1416 else if (s->high_water < (ulg)curr + WIN_INIT) { 1417 /* High water mark at or above current data, but below current data 1418 * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up 1419 * to end of window, whichever is less. 1420 */ 1421 init = (ulg)curr + WIN_INIT - s->high_water; 1422 if (init > s->window_size - s->high_water) 1423 init = s->window_size - s->high_water; 1424 zmemzero(s->window + s->high_water, (unsigned)init); 1425 s->high_water += init; 1426 } 1427 } 1428 } 1429 1430 /* =========================================================================== 1431 * Flush the current block, with given end-of-file flag. 1432 * IN assertion: strstart is set to the end of the current match. 1433 */ 1434 #define FLUSH_BLOCK_ONLY(s, last) { \ 1435 _tr_flush_block(s, (s->block_start >= 0L ? \ 1436 (charf *)&s->window[(unsigned)s->block_start] : \ 1437 (charf *)Z_NULL), \ 1438 (ulg)((long)s->strstart - s->block_start), \ 1439 (last)); \ 1440 s->block_start = s->strstart; \ 1441 flush_pending(s->strm); \ 1442 Tracev((stderr,"[FLUSH]")); \ 1443 } 1444 1445 /* Same but force premature exit if necessary. */ 1446 #define FLUSH_BLOCK(s, last) { \ 1447 FLUSH_BLOCK_ONLY(s, last); \ 1448 if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ 1449 } 1450 1451 /* =========================================================================== 1452 * Copy without compression as much as possible from the input stream, return 1453 * the current block state. 1454 * This function does not insert new strings in the dictionary since 1455 * uncompressible data is probably not useful. This function is used 1456 * only for the level=0 compression option. 1457 * NOTE: this function should be optimized to avoid extra copying from 1458 * window to pending_buf. 1459 */ 1460 local block_state deflate_stored(s, flush) 1461 deflate_state *s; 1462 int flush; 1463 { 1464 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited 1465 * to pending_buf_size, and each stored block has a 5 byte header: 1466 */ 1467 ulg max_block_size = 0xffff; 1468 ulg max_start; 1469 1470 if (max_block_size > s->pending_buf_size - 5) { 1471 max_block_size = s->pending_buf_size - 5; 1472 } 1473 1474 /* Copy as much as possible from input to output: */ 1475 for (;;) { 1476 /* Fill the window as much as possible: */ 1477 if (s->lookahead <= 1) { 1478 1479 Assert(s->strstart < s->w_size+MAX_DIST(s) || 1480 s->block_start >= (long)s->w_size, "slide too late"); 1481 1482 fill_window(s); 1483 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; 1484 1485 if (s->lookahead == 0) break; /* flush the current block */ 1486 } 1487 Assert(s->block_start >= 0L, "block gone"); 1488 1489 s->strstart += s->lookahead; 1490 s->lookahead = 0; 1491 1492 /* Emit a stored block if pending_buf will be full: */ 1493 max_start = s->block_start + max_block_size; 1494 if (s->strstart == 0 || (ulg)s->strstart >= max_start) { 1495 /* strstart == 0 is possible when wraparound on 16-bit machine */ 1496 s->lookahead = (uInt)(s->strstart - max_start); 1497 s->strstart = (uInt)max_start; 1498 FLUSH_BLOCK(s, 0); 1499 } 1500 /* Flush if we may have to slide, otherwise block_start may become 1501 * negative and the data will be gone: 1502 */ 1503 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { 1504 FLUSH_BLOCK(s, 0); 1505 } 1506 } 1507 FLUSH_BLOCK(s, flush == Z_FINISH); 1508 return flush == Z_FINISH ? finish_done : block_done; 1509 } 1510 1511 /* =========================================================================== 1512 * Compress as much as possible from the input stream, return the current 1513 * block state. 1514 * This function does not perform lazy evaluation of matches and inserts 1515 * new strings in the dictionary only for unmatched strings or for short 1516 * matches. It is used only for the fast compression options. 1517 */ 1518 local block_state deflate_fast(s, flush) 1519 deflate_state *s; 1520 int flush; 1521 { 1522 IPos hash_head; /* head of the hash chain */ 1523 int bflush; /* set if current block must be flushed */ 1524 1525 for (;;) { 1526 /* Make sure that we always have enough lookahead, except 1527 * at the end of the input file. We need MAX_MATCH bytes 1528 * for the next match, plus MIN_MATCH bytes to insert the 1529 * string following the next match. 1530 */ 1531 if (s->lookahead < MIN_LOOKAHEAD) { 1532 fill_window(s); 1533 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1534 return need_more; 1535 } 1536 if (s->lookahead == 0) break; /* flush the current block */ 1537 } 1538 1539 /* Insert the string window[strstart .. strstart+2] in the 1540 * dictionary, and set hash_head to the head of the hash chain: 1541 */ 1542 hash_head = NIL; 1543 if (s->lookahead >= MIN_MATCH) { 1544 INSERT_STRING(s, s->strstart, hash_head); 1545 } 1546 1547 /* Find the longest match, discarding those <= prev_length. 1548 * At this point we have always match_length < MIN_MATCH 1549 */ 1550 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { 1551 /* To simplify the code, we prevent matches with the string 1552 * of window index 0 (in particular we have to avoid a match 1553 * of the string with itself at the start of the input file). 1554 */ 1555 s->match_length = longest_match (s, hash_head); 1556 /* longest_match() sets match_start */ 1557 } 1558 if (s->match_length >= MIN_MATCH) { 1559 check_match(s, s->strstart, s->match_start, s->match_length); 1560 1561 _tr_tally_dist(s, s->strstart - s->match_start, 1562 s->match_length - MIN_MATCH, bflush); 1563 1564 s->lookahead -= s->match_length; 1565 1566 /* Insert new strings in the hash table only if the match length 1567 * is not too large. This saves time but degrades compression. 1568 */ 1569 #ifndef FASTEST 1570 if (s->match_length <= s->max_insert_length && 1571 s->lookahead >= MIN_MATCH) { 1572 s->match_length--; /* string at strstart already in table */ 1573 do { 1574 s->strstart++; 1575 INSERT_STRING(s, s->strstart, hash_head); 1576 /* strstart never exceeds WSIZE-MAX_MATCH, so there are 1577 * always MIN_MATCH bytes ahead. 1578 */ 1579 } while (--s->match_length != 0); 1580 s->strstart++; 1581 } else 1582 #endif 1583 { 1584 s->strstart += s->match_length; 1585 s->match_length = 0; 1586 s->ins_h = s->window[s->strstart]; 1587 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1588 #if MIN_MATCH != 3 1589 Call UPDATE_HASH() MIN_MATCH-3 more times 1590 #endif 1591 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not 1592 * matter since it will be recomputed at next deflate call. 1593 */ 1594 } 1595 } else { 1596 /* No match, output a literal byte */ 1597 Tracevv((stderr,"%c", s->window[s->strstart])); 1598 _tr_tally_lit (s, s->window[s->strstart], bflush); 1599 s->lookahead--; 1600 s->strstart++; 1601 } 1602 if (bflush) FLUSH_BLOCK(s, 0); 1603 } 1604 FLUSH_BLOCK(s, flush == Z_FINISH); 1605 return flush == Z_FINISH ? finish_done : block_done; 1606 } 1607 1608 #ifndef FASTEST 1609 /* =========================================================================== 1610 * Same as above, but achieves better compression. We use a lazy 1611 * evaluation for matches: a match is finally adopted only if there is 1612 * no better match at the next window position. 1613 */ 1614 local block_state deflate_slow(s, flush) 1615 deflate_state *s; 1616 int flush; 1617 { 1618 IPos hash_head; /* head of hash chain */ 1619 int bflush; /* set if current block must be flushed */ 1620 1621 /* Process the input block. */ 1622 for (;;) { 1623 /* Make sure that we always have enough lookahead, except 1624 * at the end of the input file. We need MAX_MATCH bytes 1625 * for the next match, plus MIN_MATCH bytes to insert the 1626 * string following the next match. 1627 */ 1628 if (s->lookahead < MIN_LOOKAHEAD) { 1629 fill_window(s); 1630 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1631 return need_more; 1632 } 1633 if (s->lookahead == 0) break; /* flush the current block */ 1634 } 1635 1636 /* Insert the string window[strstart .. strstart+2] in the 1637 * dictionary, and set hash_head to the head of the hash chain: 1638 */ 1639 hash_head = NIL; 1640 if (s->lookahead >= MIN_MATCH) { 1641 INSERT_STRING(s, s->strstart, hash_head); 1642 } 1643 1644 /* Find the longest match, discarding those <= prev_length. 1645 */ 1646 s->prev_length = s->match_length, s->prev_match = s->match_start; 1647 s->match_length = MIN_MATCH-1; 1648 1649 if (hash_head != NIL && s->prev_length < s->max_lazy_match && 1650 s->strstart - hash_head <= MAX_DIST(s)) { 1651 /* To simplify the code, we prevent matches with the string 1652 * of window index 0 (in particular we have to avoid a match 1653 * of the string with itself at the start of the input file). 1654 */ 1655 s->match_length = longest_match (s, hash_head); 1656 /* longest_match() sets match_start */ 1657 1658 if (s->match_length <= 5 && (s->strategy == Z_FILTERED 1659 #if TOO_FAR <= 32767 1660 || (s->match_length == MIN_MATCH && 1661 s->strstart - s->match_start > TOO_FAR) 1662 #endif 1663 )) { 1664 1665 /* If prev_match is also MIN_MATCH, match_start is garbage 1666 * but we will ignore the current match anyway. 1667 */ 1668 s->match_length = MIN_MATCH-1; 1669 } 1670 } 1671 /* If there was a match at the previous step and the current 1672 * match is not better, output the previous match: 1673 */ 1674 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { 1675 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; 1676 /* Do not insert strings in hash table beyond this. */ 1677 1678 check_match(s, s->strstart-1, s->prev_match, s->prev_length); 1679 1680 _tr_tally_dist(s, s->strstart -1 - s->prev_match, 1681 s->prev_length - MIN_MATCH, bflush); 1682 1683 /* Insert in hash table all strings up to the end of the match. 1684 * strstart-1 and strstart are already inserted. If there is not 1685 * enough lookahead, the last two strings are not inserted in 1686 * the hash table. 1687 */ 1688 s->lookahead -= s->prev_length-1; 1689 s->prev_length -= 2; 1690 do { 1691 if (++s->strstart <= max_insert) { 1692 INSERT_STRING(s, s->strstart, hash_head); 1693 } 1694 } while (--s->prev_length != 0); 1695 s->match_available = 0; 1696 s->match_length = MIN_MATCH-1; 1697 s->strstart++; 1698 1699 if (bflush) FLUSH_BLOCK(s, 0); 1700 1701 } else if (s->match_available) { 1702 /* If there was no match at the previous position, output a 1703 * single literal. If there was a match but the current match 1704 * is longer, truncate the previous match to a single literal. 1705 */ 1706 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1707 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1708 if (bflush) { 1709 FLUSH_BLOCK_ONLY(s, 0); 1710 } 1711 s->strstart++; 1712 s->lookahead--; 1713 if (s->strm->avail_out == 0) return need_more; 1714 } else { 1715 /* There is no previous match to compare with, wait for 1716 * the next step to decide. 1717 */ 1718 s->match_available = 1; 1719 s->strstart++; 1720 s->lookahead--; 1721 } 1722 } 1723 Assert (flush != Z_NO_FLUSH, "no flush?"); 1724 if (s->match_available) { 1725 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1726 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1727 s->match_available = 0; 1728 } 1729 FLUSH_BLOCK(s, flush == Z_FINISH); 1730 return flush == Z_FINISH ? finish_done : block_done; 1731 } 1732 #endif /* FASTEST */ 1733 1734 /* =========================================================================== 1735 * For Z_RLE, simply look for runs of bytes, generate matches only of distance 1736 * one. Do not maintain a hash table. (It will be regenerated if this run of 1737 * deflate switches away from Z_RLE.) 1738 */ 1739 local block_state deflate_rle(s, flush) 1740 deflate_state *s; 1741 int flush; 1742 { 1743 int bflush; /* set if current block must be flushed */ 1744 uInt prev; /* byte at distance one to match */ 1745 Bytef *scan, *strend; /* scan goes up to strend for length of run */ 1746 1747 for (;;) { 1748 /* Make sure that we always have enough lookahead, except 1749 * at the end of the input file. We need MAX_MATCH bytes 1750 * for the longest encodable run. 1751 */ 1752 if (s->lookahead < MAX_MATCH) { 1753 fill_window(s); 1754 if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { 1755 return need_more; 1756 } 1757 if (s->lookahead == 0) break; /* flush the current block */ 1758 } 1759 1760 /* See how many times the previous byte repeats */ 1761 s->match_length = 0; 1762 if (s->lookahead >= MIN_MATCH && s->strstart > 0) { 1763 scan = s->window + s->strstart - 1; 1764 prev = *scan; 1765 if (prev == *++scan && prev == *++scan && prev == *++scan) { 1766 strend = s->window + s->strstart + MAX_MATCH; 1767 do { 1768 } while (prev == *++scan && prev == *++scan && 1769 prev == *++scan && prev == *++scan && 1770 prev == *++scan && prev == *++scan && 1771 prev == *++scan && prev == *++scan && 1772 scan < strend); 1773 s->match_length = MAX_MATCH - (int)(strend - scan); 1774 if (s->match_length > s->lookahead) 1775 s->match_length = s->lookahead; 1776 } 1777 } 1778 1779 /* Emit match if have run of MIN_MATCH or longer, else emit literal */ 1780 if (s->match_length >= MIN_MATCH) { 1781 check_match(s, s->strstart, s->strstart - 1, s->match_length); 1782 1783 _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); 1784 1785 s->lookahead -= s->match_length; 1786 s->strstart += s->match_length; 1787 s->match_length = 0; 1788 } else { 1789 /* No match, output a literal byte */ 1790 Tracevv((stderr,"%c", s->window[s->strstart])); 1791 _tr_tally_lit (s, s->window[s->strstart], bflush); 1792 s->lookahead--; 1793 s->strstart++; 1794 } 1795 if (bflush) FLUSH_BLOCK(s, 0); 1796 } 1797 FLUSH_BLOCK(s, flush == Z_FINISH); 1798 return flush == Z_FINISH ? finish_done : block_done; 1799 } 1800 1801 /* =========================================================================== 1802 * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. 1803 * (It will be regenerated if this run of deflate switches away from Huffman.) 1804 */ 1805 local block_state deflate_huff(s, flush) 1806 deflate_state *s; 1807 int flush; 1808 { 1809 int bflush; /* set if current block must be flushed */ 1810 1811 for (;;) { 1812 /* Make sure that we have a literal to write. */ 1813 if (s->lookahead == 0) { 1814 fill_window(s); 1815 if (s->lookahead == 0) { 1816 if (flush == Z_NO_FLUSH) 1817 return need_more; 1818 break; /* flush the current block */ 1819 } 1820 } 1821 1822 /* Output a literal byte */ 1823 s->match_length = 0; 1824 Tracevv((stderr,"%c", s->window[s->strstart])); 1825 _tr_tally_lit (s, s->window[s->strstart], bflush); 1826 s->lookahead--; 1827 s->strstart++; 1828 if (bflush) FLUSH_BLOCK(s, 0); 1829 } 1830 FLUSH_BLOCK(s, flush == Z_FINISH); 1831 return flush == Z_FINISH ? finish_done : block_done; 1832 } 1833
