1 /* 2 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* deflate.c -- compress data using the deflation algorithm 7 * Copyright (C) 1995-2005 Jean-loup Gailly. 8 * For conditions of distribution and use, see copyright notice in zlib.h 9 */ 10 11 #pragma ident "@(#)deflate.c 1.1 07/03/22 SMI" 12 13 /* 14 * ALGORITHM 15 * 16 * The "deflation" process depends on being able to identify portions 17 * of the input text which are identical to earlier input (within a 18 * sliding window trailing behind the input currently being processed). 19 * 20 * The most straightforward technique turns out to be the fastest for 21 * most input files: try all possible matches and select the longest. 22 * The key feature of this algorithm is that insertions into the string 23 * dictionary are very simple and thus fast, and deletions are avoided 24 * completely. Insertions are performed at each input character, whereas 25 * string matches are performed only when the previous match ends. So it 26 * is preferable to spend more time in matches to allow very fast string 27 * insertions and avoid deletions. The matching algorithm for small 28 * strings is inspired from that of Rabin & Karp. A brute force approach 29 * is used to find longer strings when a small match has been found. 30 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze 31 * (by Leonid Broukhis). 32 * A previous version of this file used a more sophisticated algorithm 33 * (by Fiala and Greene) which is guaranteed to run in linear amortized 34 * time, but has a larger average cost, uses more memory and is patented. 35 * However the F&G algorithm may be faster for some highly redundant 36 * files if the parameter max_chain_length (described below) is too large. 37 * 38 * ACKNOWLEDGEMENTS 39 * 40 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and 41 * I found it in 'freeze' written by Leonid Broukhis. 42 * Thanks to many people for bug reports and testing. 43 * 44 * REFERENCES 45 * 46 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". 47 * Available in http://www.ietf.org/rfc/rfc1951.txt 48 * 49 * A description of the Rabin and Karp algorithm is given in the book 50 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. 51 * 52 * Fiala,E.R., and Greene,D.H. 53 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 54 * 55 */ 56 57 #include "deflate.h" 58 59 static const char deflate_copyright[] = 60 " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; 61 /* 62 If you use the zlib library in a product, an acknowledgment is welcome 63 in the documentation of your product. If for some reason you cannot 64 include such an acknowledgment, I would appreciate that you keep this 65 copyright string in the executable of your product. 66 */ 67 68 /* =========================================================================== 69 * Function prototypes. 70 */ 71 typedef enum { 72 need_more, /* block not completed, need more input or more output */ 73 block_done, /* block flush performed */ 74 finish_started, /* finish started, need only more output at next deflate */ 75 finish_done /* finish done, accept no more input or output */ 76 } block_state; 77 78 typedef block_state (*compress_func) OF((deflate_state *s, int flush)); 79 /* Compression function. Returns the block state after the call. */ 80 81 local void fill_window OF((deflate_state *s)); 82 local block_state deflate_stored OF((deflate_state *s, int flush)); 83 local block_state deflate_fast OF((deflate_state *s, int flush)); 84 #ifndef FASTEST 85 local block_state deflate_slow OF((deflate_state *s, int flush)); 86 #endif 87 local void lm_init OF((deflate_state *s)); 88 local void putShortMSB OF((deflate_state *s, uInt b)); 89 local void flush_pending OF((z_streamp strm)); 90 local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); 91 #ifndef FASTEST 92 #ifdef ASMV 93 void match_init OF((void)); /* asm code initialization */ 94 uInt longest_match OF((deflate_state *s, IPos cur_match)); 95 #else 96 local uInt longest_match OF((deflate_state *s, IPos cur_match)); 97 #endif 98 #endif 99 local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); 100 101 #ifdef DEBUG 102 local void check_match OF((deflate_state *s, IPos start, IPos match, 103 int length)); 104 #endif 105 106 /* =========================================================================== 107 * Local data 108 */ 109 110 #define NIL 0 111 /* Tail of hash chains */ 112 113 #ifndef TOO_FAR 114 # define TOO_FAR 4096 115 #endif 116 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ 117 118 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) 119 /* Minimum amount of lookahead, except at the end of the input file. 120 * See deflate.c for comments about the MIN_MATCH+1. 121 */ 122 123 /* Values for max_lazy_match, good_match and max_chain_length, depending on 124 * the desired pack level (0..9). The values given below have been tuned to 125 * exclude worst case performance for pathological files. Better values may be 126 * found for specific files. 127 */ 128 typedef struct config_s { 129 ush good_length; /* reduce lazy search above this match length */ 130 ush max_lazy; /* do not perform lazy search above this match length */ 131 ush nice_length; /* quit search above this match length */ 132 ush max_chain; 133 compress_func func; 134 } config; 135 136 #ifdef FASTEST 137 local const config configuration_table[2] = { 138 /* good lazy nice chain */ 139 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 140 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ 141 #else 142 local const config configuration_table[10] = { 143 /* good lazy nice chain */ 144 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 145 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ 146 /* 2 */ {4, 5, 16, 8, deflate_fast}, 147 /* 3 */ {4, 6, 32, 32, deflate_fast}, 148 149 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ 150 /* 5 */ {8, 16, 32, 32, deflate_slow}, 151 /* 6 */ {8, 16, 128, 128, deflate_slow}, 152 /* 7 */ {8, 32, 128, 256, deflate_slow}, 153 /* 8 */ {32, 128, 258, 1024, deflate_slow}, 154 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ 155 #endif 156 157 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 158 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different 159 * meaning. 160 */ 161 162 #define EQUAL 0 163 /* result of memcmp for equal strings */ 164 165 #ifndef NO_DUMMY_DECL 166 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ 167 #endif 168 169 /* =========================================================================== 170 * Update a hash value with the given input byte 171 * IN assertion: all calls to to UPDATE_HASH are made with consecutive 172 * input characters, so that a running hash key can be computed from the 173 * previous key instead of complete recalculation each time. 174 */ 175 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) 176 177 178 /* =========================================================================== 179 * Insert string str in the dictionary and set match_head to the previous head 180 * of the hash chain (the most recent string with same hash key). Return 181 * the previous length of the hash chain. 182 * If this file is compiled with -DFASTEST, the compression level is forced 183 * to 1, and no hash chains are maintained. 184 * IN assertion: all calls to to INSERT_STRING are made with consecutive 185 * input characters and the first MIN_MATCH bytes of str are valid 186 * (except for the last MIN_MATCH-1 bytes of the input file). 187 */ 188 #ifdef FASTEST 189 #define INSERT_STRING(s, str, match_head) \ 190 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 191 match_head = s->head[s->ins_h], \ 192 s->head[s->ins_h] = (Pos)(str)) 193 #else 194 #define INSERT_STRING(s, str, match_head) \ 195 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 196 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ 197 s->head[s->ins_h] = (Pos)(str)) 198 #endif 199 200 /* =========================================================================== 201 * Initialize the hash table (avoiding 64K overflow for 16 bit systems). 202 * prev[] will be initialized on the fly. 203 */ 204 #define CLEAR_HASH(s) \ 205 s->head[s->hash_size-1] = NIL; \ 206 (void) zmemzero((Bytef *)s->head, \ 207 (unsigned)(s->hash_size-1)*sizeof(*s->head)); 208 209 /* ========================================================================= */ 210 int ZEXPORT deflateInit_(strm, level, version, stream_size) 211 z_streamp strm; 212 int level; 213 const char *version; 214 int stream_size; 215 { 216 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, 217 Z_DEFAULT_STRATEGY, version, stream_size); 218 /* To do: ignore strm->next_in if we use it as window */ 219 } 220 221 /* ========================================================================= */ 222 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, 223 version, stream_size) 224 z_streamp strm; 225 int level; 226 int method; 227 int windowBits; 228 int memLevel; 229 int strategy; 230 const char *version; 231 int stream_size; 232 { 233 deflate_state *s; 234 int wrap = 1; 235 static const char my_version[] = ZLIB_VERSION; 236 237 ushf *overlay; 238 /* We overlay pending_buf and d_buf+l_buf. This works since the average 239 * output size for (length,distance) codes is <= 24 bits. 240 */ 241 242 if (version == Z_NULL || version[0] != my_version[0] || 243 stream_size != sizeof(z_stream)) { 244 return Z_VERSION_ERROR; 245 } 246 if (strm == Z_NULL) return Z_STREAM_ERROR; 247 248 strm->msg = Z_NULL; 249 if (strm->zalloc == (alloc_func)0) { 250 strm->zalloc = zcalloc; 251 strm->opaque = (voidpf)0; 252 } 253 if (strm->zfree == (free_func)0) strm->zfree = zcfree; 254 255 #ifdef FASTEST 256 if (level != 0) level = 1; 257 #else 258 if (level == Z_DEFAULT_COMPRESSION) level = 6; 259 #endif 260 261 if (windowBits < 0) { /* suppress zlib wrapper */ 262 wrap = 0; 263 windowBits = -windowBits; 264 } 265 #ifdef GZIP 266 else if (windowBits > 15) { 267 wrap = 2; /* write gzip wrapper instead */ 268 windowBits -= 16; 269 } 270 #endif 271 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || 272 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || 273 strategy < 0 || strategy > Z_FIXED) { 274 return Z_STREAM_ERROR; 275 } 276 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ 277 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); 278 if (s == Z_NULL) return Z_MEM_ERROR; 279 strm->state = (struct internal_state FAR *)s; 280 s->strm = strm; 281 282 s->wrap = wrap; 283 s->gzhead = Z_NULL; 284 s->w_bits = windowBits; 285 s->w_size = 1 << s->w_bits; 286 s->w_mask = s->w_size - 1; 287 288 s->hash_bits = memLevel + 7; 289 s->hash_size = 1 << s->hash_bits; 290 s->hash_mask = s->hash_size - 1; 291 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); 292 293 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); 294 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); 295 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); 296 297 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ 298 299 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); 300 s->pending_buf = (uchf *) overlay; 301 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); 302 303 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || 304 s->pending_buf == Z_NULL) { 305 s->status = FINISH_STATE; 306 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); 307 (void) deflateEnd (strm); 308 return Z_MEM_ERROR; 309 } 310 s->d_buf = overlay + s->lit_bufsize/sizeof(ush); 311 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; 312 313 s->level = level; 314 s->strategy = strategy; 315 s->method = (Byte)method; 316 317 return deflateReset(strm); 318 } 319 320 /* ========================================================================= */ 321 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) 322 z_streamp strm; 323 const Bytef *dictionary; 324 uInt dictLength; 325 { 326 deflate_state *s; 327 uInt length = dictLength; 328 uInt n; 329 IPos hash_head = 0; 330 331 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || 332 strm->state->wrap == 2 || 333 (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) 334 return Z_STREAM_ERROR; 335 336 s = strm->state; 337 if (s->wrap) 338 strm->adler = adler32(strm->adler, dictionary, dictLength); 339 340 if (length < MIN_MATCH) return Z_OK; 341 if (length > MAX_DIST(s)) { 342 length = MAX_DIST(s); 343 dictionary += dictLength - length; /* use the tail of the dictionary */ 344 } 345 (void) zmemcpy(s->window, dictionary, length); 346 s->strstart = length; 347 s->block_start = (long)length; 348 349 /* Insert all strings in the hash table (except for the last two bytes). 350 * s->lookahead stays null, so s->ins_h will be recomputed at the next 351 * call of fill_window. 352 */ 353 s->ins_h = s->window[0]; 354 UPDATE_HASH(s, s->ins_h, s->window[1]); 355 for (n = 0; n <= length - MIN_MATCH; n++) { 356 INSERT_STRING(s, n, hash_head); 357 } 358 if (hash_head) hash_head = 0; /* to make compiler happy */ 359 return Z_OK; 360 } 361 362 /* ========================================================================= */ 363 int ZEXPORT deflateReset (strm) 364 z_streamp strm; 365 { 366 deflate_state *s; 367 368 if (strm == Z_NULL || strm->state == Z_NULL || 369 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { 370 return Z_STREAM_ERROR; 371 } 372 373 strm->total_in = strm->total_out = 0; 374 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ 375 strm->data_type = Z_UNKNOWN; 376 377 s = (deflate_state *)strm->state; 378 s->pending = 0; 379 s->pending_out = s->pending_buf; 380 381 if (s->wrap < 0) { 382 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ 383 } 384 s->status = s->wrap ? INIT_STATE : BUSY_STATE; 385 strm->adler = 386 #ifdef GZIP 387 s->wrap == 2 ? crc32(0L, Z_NULL, 0) : 388 #endif 389 adler32(0L, Z_NULL, 0); 390 s->last_flush = Z_NO_FLUSH; 391 392 _tr_init(s); 393 lm_init(s); 394 395 return Z_OK; 396 } 397 398 /* ========================================================================= */ 399 int ZEXPORT deflateSetHeader (strm, head) 400 z_streamp strm; 401 gz_headerp head; 402 { 403 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 404 if (strm->state->wrap != 2) return Z_STREAM_ERROR; 405 strm->state->gzhead = head; 406 return Z_OK; 407 } 408 409 /* ========================================================================= */ 410 int ZEXPORT deflatePrime (strm, bits, value) 411 z_streamp strm; 412 int bits; 413 int value; 414 { 415 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 416 strm->state->bi_valid = bits; 417 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); 418 return Z_OK; 419 } 420 421 /* ========================================================================= */ 422 int ZEXPORT deflateParams(strm, level, strategy) 423 z_streamp strm; 424 int level; 425 int strategy; 426 { 427 deflate_state *s; 428 compress_func func; 429 int err = Z_OK; 430 431 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 432 s = strm->state; 433 434 #ifdef FASTEST 435 if (level != 0) level = 1; 436 #else 437 if (level == Z_DEFAULT_COMPRESSION) level = 6; 438 #endif 439 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { 440 return Z_STREAM_ERROR; 441 } 442 func = configuration_table[s->level].func; 443 444 if (func != configuration_table[level].func && strm->total_in != 0) { 445 /* Flush the last buffer: */ 446 err = deflate(strm, Z_PARTIAL_FLUSH); 447 } 448 if (s->level != level) { 449 s->level = level; 450 s->max_lazy_match = configuration_table[level].max_lazy; 451 s->good_match = configuration_table[level].good_length; 452 s->nice_match = configuration_table[level].nice_length; 453 s->max_chain_length = configuration_table[level].max_chain; 454 } 455 s->strategy = strategy; 456 return err; 457 } 458 459 /* ========================================================================= */ 460 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) 461 z_streamp strm; 462 int good_length; 463 int max_lazy; 464 int nice_length; 465 int max_chain; 466 { 467 deflate_state *s; 468 469 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 470 s = strm->state; 471 s->good_match = good_length; 472 s->max_lazy_match = max_lazy; 473 s->nice_match = nice_length; 474 s->max_chain_length = max_chain; 475 return Z_OK; 476 } 477 478 /* ========================================================================= 479 * For the default windowBits of 15 and memLevel of 8, this function returns 480 * a close to exact, as well as small, upper bound on the compressed size. 481 * They are coded as constants here for a reason--if the #define's are 482 * changed, then this function needs to be changed as well. The return 483 * value for 15 and 8 only works for those exact settings. 484 * 485 * For any setting other than those defaults for windowBits and memLevel, 486 * the value returned is a conservative worst case for the maximum expansion 487 * resulting from using fixed blocks instead of stored blocks, which deflate 488 * can emit on compressed data for some combinations of the parameters. 489 * 490 * This function could be more sophisticated to provide closer upper bounds 491 * for every combination of windowBits and memLevel, as well as wrap. 492 * But even the conservative upper bound of about 14% expansion does not 493 * seem onerous for output buffer allocation. 494 */ 495 uLong ZEXPORT deflateBound(strm, sourceLen) 496 z_streamp strm; 497 uLong sourceLen; 498 { 499 deflate_state *s; 500 uLong destLen; 501 502 /* conservative upper bound */ 503 destLen = sourceLen + 504 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; 505 506 /* if can't get parameters, return conservative bound */ 507 if (strm == Z_NULL || strm->state == Z_NULL) 508 return destLen; 509 510 /* if not default parameters, return conservative bound */ 511 s = strm->state; 512 if (s->w_bits != 15 || s->hash_bits != 8 + 7) 513 return destLen; 514 515 /* default settings: return tight bound for that case */ 516 return compressBound(sourceLen); 517 } 518 519 /* ========================================================================= 520 * Put a short in the pending buffer. The 16-bit value is put in MSB order. 521 * IN assertion: the stream state is correct and there is enough room in 522 * pending_buf. 523 */ 524 local void putShortMSB (s, b) 525 deflate_state *s; 526 uInt b; 527 { 528 put_byte(s, (Byte)(b >> 8)); 529 put_byte(s, (Byte)(b & 0xff)); 530 } 531 532 /* ========================================================================= 533 * Flush as much pending output as possible. All deflate() output goes 534 * through this function so some applications may wish to modify it 535 * to avoid allocating a large strm->next_out buffer and copying into it. 536 * (See also read_buf()). 537 */ 538 local void flush_pending(strm) 539 z_streamp strm; 540 { 541 unsigned len = strm->state->pending; 542 543 if (len > strm->avail_out) len = strm->avail_out; 544 if (len == 0) return; 545 546 zmemcpy(strm->next_out, strm->state->pending_out, len); 547 strm->next_out += len; 548 strm->state->pending_out += len; 549 strm->total_out += len; 550 strm->avail_out -= len; 551 strm->state->pending -= len; 552 if (strm->state->pending == 0) { 553 strm->state->pending_out = strm->state->pending_buf; 554 } 555 } 556 557 /* ========================================================================= */ 558 int ZEXPORT deflate (strm, flush) 559 z_streamp strm; 560 int flush; 561 { 562 int old_flush; /* value of flush param for previous deflate call */ 563 deflate_state *s; 564 565 if (strm == Z_NULL || strm->state == Z_NULL || 566 flush > Z_FINISH || flush < 0) { 567 return Z_STREAM_ERROR; 568 } 569 s = strm->state; 570 571 if (strm->next_out == Z_NULL || 572 (strm->next_in == Z_NULL && strm->avail_in != 0) || 573 (s->status == FINISH_STATE && flush != Z_FINISH)) { 574 ERR_RETURN(strm, Z_STREAM_ERROR); 575 } 576 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 577 578 s->strm = strm; /* just in case */ 579 old_flush = s->last_flush; 580 s->last_flush = flush; 581 582 /* Write the header */ 583 if (s->status == INIT_STATE) { 584 #ifdef GZIP 585 if (s->wrap == 2) { 586 strm->adler = crc32(0L, Z_NULL, 0); 587 put_byte(s, 31); 588 put_byte(s, 139); 589 put_byte(s, 8); 590 if (s->gzhead == NULL) { 591 put_byte(s, 0); 592 put_byte(s, 0); 593 put_byte(s, 0); 594 put_byte(s, 0); 595 put_byte(s, 0); 596 put_byte(s, s->level == 9 ? 2 : 597 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 598 4 : 0)); 599 put_byte(s, OS_CODE); 600 s->status = BUSY_STATE; 601 } 602 else { 603 put_byte(s, (s->gzhead->text ? 1 : 0) + 604 (s->gzhead->hcrc ? 2 : 0) + 605 (s->gzhead->extra == Z_NULL ? 0 : 4) + 606 (s->gzhead->name == Z_NULL ? 0 : 8) + 607 (s->gzhead->comment == Z_NULL ? 0 : 16) 608 ); 609 put_byte(s, (Byte)(s->gzhead->time & 0xff)); 610 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); 611 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); 612 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); 613 put_byte(s, s->level == 9 ? 2 : 614 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 615 4 : 0)); 616 put_byte(s, s->gzhead->os & 0xff); 617 if (s->gzhead->extra != NULL) { 618 put_byte(s, s->gzhead->extra_len & 0xff); 619 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); 620 } 621 if (s->gzhead->hcrc) 622 strm->adler = crc32(strm->adler, s->pending_buf, 623 s->pending); 624 s->gzindex = 0; 625 s->status = EXTRA_STATE; 626 } 627 } 628 else 629 #endif 630 { 631 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 632 uInt level_flags; 633 634 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 635 level_flags = 0; 636 else if (s->level < 6) 637 level_flags = 1; 638 else if (s->level == 6) 639 level_flags = 2; 640 else 641 level_flags = 3; 642 header |= (level_flags << 6); 643 if (s->strstart != 0) header |= PRESET_DICT; 644 header += 31 - (header % 31); 645 646 s->status = BUSY_STATE; 647 putShortMSB(s, header); 648 649 /* Save the adler32 of the preset dictionary: */ 650 if (s->strstart != 0) { 651 putShortMSB(s, (uInt)(strm->adler >> 16)); 652 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 653 } 654 strm->adler = adler32(0L, Z_NULL, 0); 655 } 656 } 657 #ifdef GZIP 658 if (s->status == EXTRA_STATE) { 659 if (s->gzhead->extra != NULL) { 660 uInt beg = s->pending; /* start of bytes to update crc */ 661 662 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { 663 if (s->pending == s->pending_buf_size) { 664 if (s->gzhead->hcrc && s->pending > beg) 665 strm->adler = crc32(strm->adler, s->pending_buf + beg, 666 s->pending - beg); 667 flush_pending(strm); 668 beg = s->pending; 669 if (s->pending == s->pending_buf_size) 670 break; 671 } 672 put_byte(s, s->gzhead->extra[s->gzindex]); 673 s->gzindex++; 674 } 675 if (s->gzhead->hcrc && s->pending > beg) 676 strm->adler = crc32(strm->adler, s->pending_buf + beg, 677 s->pending - beg); 678 if (s->gzindex == s->gzhead->extra_len) { 679 s->gzindex = 0; 680 s->status = NAME_STATE; 681 } 682 } 683 else 684 s->status = NAME_STATE; 685 } 686 if (s->status == NAME_STATE) { 687 if (s->gzhead->name != NULL) { 688 uInt beg = s->pending; /* start of bytes to update crc */ 689 int val; 690 691 do { 692 if (s->pending == s->pending_buf_size) { 693 if (s->gzhead->hcrc && s->pending > beg) 694 strm->adler = crc32(strm->adler, s->pending_buf + beg, 695 s->pending - beg); 696 flush_pending(strm); 697 beg = s->pending; 698 if (s->pending == s->pending_buf_size) { 699 val = 1; 700 break; 701 } 702 } 703 val = s->gzhead->name[s->gzindex++]; 704 put_byte(s, val); 705 } while (val != 0); 706 if (s->gzhead->hcrc && s->pending > beg) 707 strm->adler = crc32(strm->adler, s->pending_buf + beg, 708 s->pending - beg); 709 if (val == 0) { 710 s->gzindex = 0; 711 s->status = COMMENT_STATE; 712 } 713 } 714 else 715 s->status = COMMENT_STATE; 716 } 717 if (s->status == COMMENT_STATE) { 718 if (s->gzhead->comment != NULL) { 719 uInt beg = s->pending; /* start of bytes to update crc */ 720 int val; 721 722 do { 723 if (s->pending == s->pending_buf_size) { 724 if (s->gzhead->hcrc && s->pending > beg) 725 strm->adler = crc32(strm->adler, s->pending_buf + beg, 726 s->pending - beg); 727 flush_pending(strm); 728 beg = s->pending; 729 if (s->pending == s->pending_buf_size) { 730 val = 1; 731 break; 732 } 733 } 734 val = s->gzhead->comment[s->gzindex++]; 735 put_byte(s, val); 736 } while (val != 0); 737 if (s->gzhead->hcrc && s->pending > beg) 738 strm->adler = crc32(strm->adler, s->pending_buf + beg, 739 s->pending - beg); 740 if (val == 0) 741 s->status = HCRC_STATE; 742 } 743 else 744 s->status = HCRC_STATE; 745 } 746 if (s->status == HCRC_STATE) { 747 if (s->gzhead->hcrc) { 748 if (s->pending + 2 > s->pending_buf_size) 749 flush_pending(strm); 750 if (s->pending + 2 <= s->pending_buf_size) { 751 put_byte(s, (Byte)(strm->adler & 0xff)); 752 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 753 strm->adler = crc32(0L, Z_NULL, 0); 754 s->status = BUSY_STATE; 755 } 756 } 757 else 758 s->status = BUSY_STATE; 759 } 760 #endif 761 762 /* Flush as much pending output as possible */ 763 if (s->pending != 0) { 764 flush_pending(strm); 765 if (strm->avail_out == 0) { 766 /* Since avail_out is 0, deflate will be called again with 767 * more output space, but possibly with both pending and 768 * avail_in equal to zero. There won't be anything to do, 769 * but this is not an error situation so make sure we 770 * return OK instead of BUF_ERROR at next call of deflate: 771 */ 772 s->last_flush = -1; 773 return Z_OK; 774 } 775 776 /* Make sure there is something to do and avoid duplicate consecutive 777 * flushes. For repeated and useless calls with Z_FINISH, we keep 778 * returning Z_STREAM_END instead of Z_BUF_ERROR. 779 */ 780 } else if (strm->avail_in == 0 && flush <= old_flush && 781 flush != Z_FINISH) { 782 ERR_RETURN(strm, Z_BUF_ERROR); 783 } 784 785 /* User must not provide more input after the first FINISH: */ 786 if (s->status == FINISH_STATE && strm->avail_in != 0) { 787 ERR_RETURN(strm, Z_BUF_ERROR); 788 } 789 790 /* Start a new block or continue the current one. 791 */ 792 if (strm->avail_in != 0 || s->lookahead != 0 || 793 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 794 block_state bstate; 795 796 bstate = (*(configuration_table[s->level].func))(s, flush); 797 798 if (bstate == finish_started || bstate == finish_done) { 799 s->status = FINISH_STATE; 800 } 801 if (bstate == need_more || bstate == finish_started) { 802 if (strm->avail_out == 0) { 803 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 804 } 805 return Z_OK; 806 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 807 * of deflate should use the same flush parameter to make sure 808 * that the flush is complete. So we don't have to output an 809 * empty block here, this will be done at next call. This also 810 * ensures that for a very small output buffer, we emit at most 811 * one empty block. 812 */ 813 } 814 if (bstate == block_done) { 815 if (flush == Z_PARTIAL_FLUSH) { 816 _tr_align(s); 817 } else { /* FULL_FLUSH or SYNC_FLUSH */ 818 _tr_stored_block(s, (char*)0, 0L, 0); 819 /* For a full flush, this empty block will be recognized 820 * as a special marker by inflate_sync(). 821 */ 822 if (flush == Z_FULL_FLUSH) { 823 CLEAR_HASH(s); /* forget history */ 824 } 825 } 826 flush_pending(strm); 827 if (strm->avail_out == 0) { 828 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 829 return Z_OK; 830 } 831 } 832 } 833 Assert(strm->avail_out > 0, "bug2"); 834 835 if (flush != Z_FINISH) return Z_OK; 836 if (s->wrap <= 0) return Z_STREAM_END; 837 838 /* Write the trailer */ 839 #ifdef GZIP 840 if (s->wrap == 2) { 841 put_byte(s, (Byte)(strm->adler & 0xff)); 842 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 843 put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 844 put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 845 put_byte(s, (Byte)(strm->total_in & 0xff)); 846 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 847 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 848 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 849 } 850 else 851 #endif 852 { 853 putShortMSB(s, (uInt)(strm->adler >> 16)); 854 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 855 } 856 flush_pending(strm); 857 /* If avail_out is zero, the application will call deflate again 858 * to flush the rest. 859 */ 860 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 861 return s->pending != 0 ? Z_OK : Z_STREAM_END; 862 } 863 864 /* ========================================================================= */ 865 int ZEXPORT deflateEnd (strm) 866 z_streamp strm; 867 { 868 int status; 869 870 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 871 872 status = strm->state->status; 873 if (status != INIT_STATE && 874 status != EXTRA_STATE && 875 status != NAME_STATE && 876 status != COMMENT_STATE && 877 status != HCRC_STATE && 878 status != BUSY_STATE && 879 status != FINISH_STATE) { 880 return Z_STREAM_ERROR; 881 } 882 883 /* Deallocate in reverse order of allocations: */ 884 TRY_FREE(strm, strm->state->pending_buf); 885 TRY_FREE(strm, strm->state->head); 886 TRY_FREE(strm, strm->state->prev); 887 TRY_FREE(strm, strm->state->window); 888 889 ZFREE(strm, strm->state); 890 strm->state = Z_NULL; 891 892 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 893 } 894 895 /* ========================================================================= 896 * Copy the source state to the destination state. 897 * To simplify the source, this is not supported for 16-bit MSDOS (which 898 * doesn't have enough memory anyway to duplicate compression states). 899 */ 900 int ZEXPORT deflateCopy (dest, source) 901 z_streamp dest; 902 z_streamp source; 903 { 904 #ifdef MAXSEG_64K 905 return Z_STREAM_ERROR; 906 #else 907 deflate_state *ds; 908 deflate_state *ss; 909 ushf *overlay; 910 911 912 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 913 return Z_STREAM_ERROR; 914 } 915 916 ss = source->state; 917 918 zmemcpy(dest</