#include "deflate.h"
Go to the source code of this file.
Data Structures | |
struct | config_s |
struct | static_tree_desc_s |
Defines | |
#define | NIL 0 |
#define | TOO_FAR 4096 |
#define | MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) |
#define | EQUAL 0 |
#define | UPDATE_HASH(s, h, c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) |
#define | INSERT_STRING(s, str, match_head) |
#define | CLEAR_HASH(s) |
#define | check_match(s, start, match, length) |
#define | FLUSH_BLOCK_ONLY(s, eof) |
#define | FLUSH_BLOCK(s, eof) |
Typedefs | |
typedef block_state compress_func | OF ((deflate_state *s, int flush)) |
typedef config_s | config |
Enumerations | |
enum | block_state { need_more, block_done, finish_started, finish_done } |
Functions | |
local void fill_window | OF ((deflate_state *s)) |
local block_state deflate_stored | OF ((deflate_state *s, int flush)) |
local void putShortMSB | OF ((deflate_state *s, uInt b)) |
local void flush_pending | OF ((z_streamp strm)) |
local int read_buf | OF ((z_streamp strm, Bytef *buf, unsigned size)) |
local uInt longest_match | OF ((deflate_state *s, IPos cur_match)) |
int ZEXPORT | deflateInit_ (z_streamp strm, int level, const char *version, int stream_size) |
int ZEXPORT | deflateInit2_ (z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy, const char *version, int stream_size) |
int ZEXPORT | deflateSetDictionary (z_streamp strm, const Bytef *dictionary, uInt dictLength) |
int ZEXPORT | deflateReset (z_streamp strm) |
int ZEXPORT | deflatePrime (z_streamp strm, int bits, int value) |
int ZEXPORT | deflateParams (z_streamp strm, int level, int strategy) |
uLong ZEXPORT | deflateBound (z_streamp strm, uLong sourceLen) |
local void | putShortMSB (deflate_state *s, uInt b) |
local void | flush_pending (z_streamp strm) |
int ZEXPORT | deflate (z_streamp strm, int flush) |
int ZEXPORT | deflateEnd (z_streamp strm) |
int ZEXPORT | deflateCopy (z_streamp dest, z_streamp source) |
local int | read_buf (z_streamp strm, Bytef *buf, unsigned size) |
local void | lm_init (deflate_state *s) |
local uInt | longest_match (deflate_state *s, IPos cur_match) |
local uInt | longest_match_fast (deflate_state *s, IPos cur_match) |
local void | fill_window (deflate_state *s) |
local block_state | deflate_stored (deflate_state *s, int flush) |
local block_state | deflate_fast (deflate_state *s, int flush) |
local block_state | deflate_slow (deflate_state *s, int flush) |
Variables | |
const char | deflate_copyright [] |
local const config | configuration_table [10] |
#define check_match | ( | s, | |||
start, | |||||
match, | |||||
length | ) |
Definition at line 1038 of file deflate.cc.
#define CLEAR_HASH | ( | s | ) |
#define EQUAL 0 |
Definition at line 157 of file deflate.cc.
#define FLUSH_BLOCK | ( | s, | |||
eof | ) |
Value:
{ \ FLUSH_BLOCK_ONLY(s, eof); \ if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ }
Definition at line 1159 of file deflate.cc.
Referenced by deflate_stored().
#define FLUSH_BLOCK_ONLY | ( | s, | |||
eof | ) |
Value:
{ \ _tr_flush_block(s, (s->block_start >= 0L ? \ (charf *)&s->window[(unsigned)s->block_start] : \ (charf *)Z_NULL), \ (ulg)((long)s->strstart - s->block_start), \ (eof)); \ s->block_start = s->strstart; \ flush_pending(s->strm); \ Tracev((stderr,(char*)"[FLUSH]")); \ }
Definition at line 1147 of file deflate.cc.
#define INSERT_STRING | ( | s, | |||
str, | |||||
match_head | ) |
Value:
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ s->head[s->ins_h] = (Pos)(str))
Definition at line 189 of file deflate.cc.
Referenced by deflateSetDictionary().
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) |
Definition at line 113 of file deflate.cc.
Referenced by deflate_fast(), deflate_slow(), fill_window(), longest_match(), and longest_match_fast().
#define NIL 0 |
Definition at line 105 of file deflate.cc.
Referenced by deflate_fast(), deflate_slow(), fill_window(), and longest_match().
#define TOO_FAR 4096 |
Definition at line 109 of file deflate.cc.
#define UPDATE_HASH | ( | s, | |||
h, | |||||
c | ) | (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) |
local void bi_flush OF |
Definition at line 73 of file deflate.cc.
enum block_state |
Definition at line 66 of file deflate.cc.
00066 { 00067 need_more, /* block not completed, need more input or more output */ 00068 block_done, /* block flush performed */ 00069 finish_started, /* finish started, need only more output at next deflate */ 00070 finish_done /* finish done, accept no more input or output */ 00071 } block_state;
int ZEXPORT deflate | ( | z_streamp | strm, | |
int | flush | |||
) |
Definition at line 496 of file deflate.cc.
References _tr_align(), _tr_stored_block(), adler32(), block_done, CLEAR_HASH, crc32(), finish_done, finish_started, flush_pending(), need_more, and putShortMSB().
Referenced by compress2(), and deflateParams().
00497 { 00498 int old_flush; /* value of flush param for previous deflate call */ 00499 deflate_state *s; 00500 00501 if (strm == Z_NULL || strm->state == Z_NULL || 00502 flush > Z_FINISH || flush < 0) { 00503 return Z_STREAM_ERROR; 00504 } 00505 s = strm->state; 00506 00507 if (strm->next_out == Z_NULL || 00508 (strm->next_in == Z_NULL && strm->avail_in != 0) || 00509 (s->status == FINISH_STATE && flush != Z_FINISH)) { 00510 ERR_RETURN(strm, Z_STREAM_ERROR); 00511 } 00512 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 00513 00514 s->strm = strm; /* just in case */ 00515 old_flush = s->last_flush; 00516 s->last_flush = flush; 00517 00518 /* Write the header */ 00519 if (s->status == INIT_STATE) { 00520 #ifdef GZIP 00521 if (s->wrap == 2) { 00522 put_byte(s, 31); 00523 put_byte(s, 139); 00524 put_byte(s, 8); 00525 put_byte(s, 0); 00526 put_byte(s, 0); 00527 put_byte(s, 0); 00528 put_byte(s, 0); 00529 put_byte(s, 0); 00530 put_byte(s, s->level == 9 ? 2 : 00531 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 00532 4 : 0)); 00533 put_byte(s, 255); 00534 s->status = BUSY_STATE; 00535 strm->adler = crc32(0L, Z_NULL, 0); 00536 } 00537 else 00538 #endif 00539 { 00540 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 00541 uInt level_flags; 00542 00543 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 00544 level_flags = 0; 00545 else if (s->level < 6) 00546 level_flags = 1; 00547 else if (s->level == 6) 00548 level_flags = 2; 00549 else 00550 level_flags = 3; 00551 header |= (level_flags << 6); 00552 if (s->strstart != 0) header |= PRESET_DICT; 00553 header += 31 - (header % 31); 00554 00555 s->status = BUSY_STATE; 00556 putShortMSB(s, header); 00557 00558 /* Save the adler32 of the preset dictionary: */ 00559 if (s->strstart != 0) { 00560 putShortMSB(s, (uInt)(strm->adler >> 16)); 00561 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 00562 } 00563 strm->adler = adler32(0L, Z_NULL, 0); 00564 } 00565 } 00566 00567 /* Flush as much pending output as possible */ 00568 if (s->pending != 0) { 00569 flush_pending(strm); 00570 if (strm->avail_out == 0) { 00571 /* Since avail_out is 0, deflate will be called again with 00572 * more output space, but possibly with both pending and 00573 * avail_in equal to zero. There won't be anything to do, 00574 * but this is not an error situation so make sure we 00575 * return OK instead of BUF_ERROR at next call of deflate: 00576 */ 00577 s->last_flush = -1; 00578 return Z_OK; 00579 } 00580 00581 /* Make sure there is something to do and avoid duplicate consecutive 00582 * flushes. For repeated and useless calls with Z_FINISH, we keep 00583 * returning Z_STREAM_END instead of Z_BUF_ERROR. 00584 */ 00585 } else if (strm->avail_in == 0 && flush <= old_flush && 00586 flush != Z_FINISH) { 00587 ERR_RETURN(strm, Z_BUF_ERROR); 00588 } 00589 00590 /* User must not provide more input after the first FINISH: */ 00591 if (s->status == FINISH_STATE && strm->avail_in != 0) { 00592 ERR_RETURN(strm, Z_BUF_ERROR); 00593 } 00594 00595 /* Start a new block or continue the current one. 00596 */ 00597 if (strm->avail_in != 0 || s->lookahead != 0 || 00598 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 00599 block_state bstate; 00600 00601 bstate = (*(configuration_table[s->level].func))(s, flush); 00602 00603 if (bstate == finish_started || bstate == finish_done) { 00604 s->status = FINISH_STATE; 00605 } 00606 if (bstate == need_more || bstate == finish_started) { 00607 if (strm->avail_out == 0) { 00608 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 00609 } 00610 return Z_OK; 00611 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 00612 * of deflate should use the same flush parameter to make sure 00613 * that the flush is complete. So we don't have to output an 00614 * empty block here, this will be done at next call. This also 00615 * ensures that for a very small output buffer, we emit at most 00616 * one empty block. 00617 */ 00618 } 00619 if (bstate == block_done) { 00620 if (flush == Z_PARTIAL_FLUSH) { 00621 _tr_align(s); 00622 } else { /* FULL_FLUSH or SYNC_FLUSH */ 00623 _tr_stored_block(s, (char*)0, 0L, 0); 00624 /* For a full flush, this empty block will be recognized 00625 * as a special marker by inflate_sync(). 00626 */ 00627 if (flush == Z_FULL_FLUSH) { 00628 CLEAR_HASH(s); /* forget history */ 00629 } 00630 } 00631 flush_pending(strm); 00632 if (strm->avail_out == 0) { 00633 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 00634 return Z_OK; 00635 } 00636 } 00637 } 00638 Assert(strm->avail_out > 0, (char*)"bug2"); 00639 00640 if (flush != Z_FINISH) return Z_OK; 00641 if (s->wrap <= 0) return Z_STREAM_END; 00642 00643 /* Write the trailer */ 00644 #ifdef GZIP 00645 if (s->wrap == 2) { 00646 put_byte(s, (Byte)(strm->adler & 0xff)); 00647 put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 00648 put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 00649 put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 00650 put_byte(s, (Byte)(strm->total_in & 0xff)); 00651 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 00652 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 00653 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 00654 } 00655 else 00656 #endif 00657 { 00658 putShortMSB(s, (uInt)(strm->adler >> 16)); 00659 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 00660 } 00661 flush_pending(strm); 00662 /* If avail_out is zero, the application will call deflate again 00663 * to flush the rest. 00664 */ 00665 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 00666 return s->pending != 0 ? Z_OK : Z_STREAM_END; 00667 }
local block_state deflate_fast | ( | deflate_state * | s, | |
int | flush | |||
) |
Definition at line 1229 of file deflate.cc.
References fill_window(), MIN_LOOKAHEAD, need_more, and NIL.
01230 { 01231 IPos hash_head = NIL; /* head of the hash chain */ 01232 int bflush; /* set if current block must be flushed */ 01233 01234 for (;;) { 01235 /* Make sure that we always have enough lookahead, except 01236 * at the end of the input file. We need MAX_MATCH bytes 01237 * for the next match, plus MIN_MATCH bytes to insert the 01238 * string following the next match. 01239 */ 01240 if (s->lookahead < MIN_LOOKAHEAD) { 01241 fill_window(s); 01242 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 01243 return need_more; 01244 } 01245 if (s->lookahead == 0) break; /* flush the current block */ 01246 } 01247 01248 /* Insert the string window[strstart .. strstart+2] in the 01249 * dictionary, and set hash_head to the head of the hash chain: 01250 */ 01251 if (s->lookahead >= MIN_MATCH) { 01252 INSERT_STRING(s, s->strstart, hash_head); 01253 } 01254 01255 /* Find the longest match, discarding those <= prev_length. 01256 * At this point we have always match_length < MIN_MATCH 01257 */ 01258 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { 01259 /* To simplify the code, we prevent matches with the string 01260 * of window index 0 (in particular we have to avoid a match 01261 * of the string with itself at the start of the input file). 01262 */ 01263 #ifdef FASTEST 01264 if ((s->strategy < Z_HUFFMAN_ONLY) || 01265 (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { 01266 s->match_length = longest_match_fast (s, hash_head); 01267 } 01268 #else 01269 if (s->strategy < Z_HUFFMAN_ONLY) { 01270 s->match_length = longest_match (s, hash_head); 01271 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 01272 s->match_length = longest_match_fast (s, hash_head); 01273 } 01274 #endif 01275 /* longest_match() or longest_match_fast() sets match_start */ 01276 } 01277 if (s->match_length >= MIN_MATCH) { 01278 check_match(s, s->strstart, s->match_start, s->match_length); 01279 01280 _tr_tally_dist(s, s->strstart - s->match_start, 01281 s->match_length - MIN_MATCH, bflush); 01282 01283 s->lookahead -= s->match_length; 01284 01285 /* Insert new strings in the hash table only if the match length 01286 * is not too large. This saves time but degrades compression. 01287 */ 01288 #ifndef FASTEST 01289 if (s->match_length <= s->max_insert_length && 01290 s->lookahead >= MIN_MATCH) { 01291 s->match_length--; /* string at strstart already in table */ 01292 do { 01293 s->strstart++; 01294 INSERT_STRING(s, s->strstart, hash_head); 01295 /* strstart never exceeds WSIZE-MAX_MATCH, so there are 01296 * always MIN_MATCH bytes ahead. 01297 */ 01298 } while (--s->match_length != 0); 01299 s->strstart++; 01300 } else 01301 #endif 01302 { 01303 s->strstart += s->match_length; 01304 s->match_length = 0; 01305 s->ins_h = s->window[s->strstart]; 01306 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 01307 #if MIN_MATCH != 3 01308 Call UPDATE_HASH() MIN_MATCH-3 more times 01309 #endif 01310 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not 01311 * matter since it will be recomputed at next deflate call. 01312 */ 01313 } 01314 } else { 01315 /* No match, output a literal byte */ 01316 Tracevv((stderr,"%c", s->window[s->strstart])); 01317 _tr_tally_lit (s, s->window[s->strstart], bflush); 01318 s->lookahead--; 01319 s->strstart++; 01320 } 01321 if (bflush) FLUSH_BLOCK(s, 0); 01322 } 01323 FLUSH_BLOCK(s, flush == Z_FINISH); 01324 return flush == Z_FINISH ? finish_done : block_done; 01325 }
local block_state deflate_slow | ( | deflate_state * | s, | |
int | flush | |||
) |
Definition at line 1333 of file deflate.cc.
References fill_window(), MIN_LOOKAHEAD, need_more, and NIL.
01334 { 01335 IPos hash_head = NIL; /* head of hash chain */ 01336 int bflush; /* set if current block must be flushed */ 01337 01338 /* Process the input block. */ 01339 for (;;) { 01340 /* Make sure that we always have enough lookahead, except 01341 * at the end of the input file. We need MAX_MATCH bytes 01342 * for the next match, plus MIN_MATCH bytes to insert the 01343 * string following the next match. 01344 */ 01345 if (s->lookahead < MIN_LOOKAHEAD) { 01346 fill_window(s); 01347 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 01348 return need_more; 01349 } 01350 if (s->lookahead == 0) break; /* flush the current block */ 01351 } 01352 01353 /* Insert the string window[strstart .. strstart+2] in the 01354 * dictionary, and set hash_head to the head of the hash chain: 01355 */ 01356 if (s->lookahead >= MIN_MATCH) { 01357 INSERT_STRING(s, s->strstart, hash_head); 01358 } 01359 01360 /* Find the longest match, discarding those <= prev_length. 01361 */ 01362 s->prev_length = s->match_length, s->prev_match = s->match_start; 01363 s->match_length = MIN_MATCH-1; 01364 01365 if (hash_head != NIL && s->prev_length < s->max_lazy_match && 01366 s->strstart - hash_head <= MAX_DIST(s)) { 01367 /* To simplify the code, we prevent matches with the string 01368 * of window index 0 (in particular we have to avoid a match 01369 * of the string with itself at the start of the input file). 01370 */ 01371 if (s->strategy < Z_HUFFMAN_ONLY) { 01372 s->match_length = longest_match (s, hash_head); 01373 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 01374 s->match_length = longest_match_fast (s, hash_head); 01375 } 01376 /* longest_match() or longest_match_fast() sets match_start */ 01377 01378 if (s->match_length <= 5 && (s->strategy == Z_FILTERED 01379 #if TOO_FAR <= 32767 01380 || (s->match_length == MIN_MATCH && 01381 s->strstart - s->match_start > TOO_FAR) 01382 #endif 01383 )) { 01384 01385 /* If prev_match is also MIN_MATCH, match_start is garbage 01386 * but we will ignore the current match anyway. 01387 */ 01388 s->match_length = MIN_MATCH-1; 01389 } 01390 } 01391 /* If there was a match at the previous step and the current 01392 * match is not better, output the previous match: 01393 */ 01394 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { 01395 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; 01396 /* Do not insert strings in hash table beyond this. */ 01397 01398 check_match(s, s->strstart-1, s->prev_match, s->prev_length); 01399 01400 _tr_tally_dist(s, s->strstart -1 - s->prev_match, 01401 s->prev_length - MIN_MATCH, bflush); 01402 01403 /* Insert in hash table all strings up to the end of the match. 01404 * strstart-1 and strstart are already inserted. If there is not 01405 * enough lookahead, the last two strings are not inserted in 01406 * the hash table. 01407 */ 01408 s->lookahead -= s->prev_length-1; 01409 s->prev_length -= 2; 01410 do { 01411 if (++s->strstart <= max_insert) { 01412 INSERT_STRING(s, s->strstart, hash_head); 01413 } 01414 } while (--s->prev_length != 0); 01415 s->match_available = 0; 01416 s->match_length = MIN_MATCH-1; 01417 s->strstart++; 01418 01419 if (bflush) FLUSH_BLOCK(s, 0); 01420 01421 } else if (s->match_available) { 01422 /* If there was no match at the previous position, output a 01423 * single literal. If there was a match but the current match 01424 * is longer, truncate the previous match to a single literal. 01425 */ 01426 Tracevv((stderr,(char*)"%c", s->window[s->strstart-1])); 01427 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 01428 if (bflush) { 01429 FLUSH_BLOCK_ONLY(s, 0); 01430 } 01431 s->strstart++; 01432 s->lookahead--; 01433 if (s->strm->avail_out == 0) return need_more; 01434 } else { 01435 /* There is no previous match to compare with, wait for 01436 * the next step to decide. 01437 */ 01438 s->match_available = 1; 01439 s->strstart++; 01440 s->lookahead--; 01441 } 01442 } 01443 Assert (flush != Z_NO_FLUSH, (char*)"no flush?"); 01444 if (s->match_available) { 01445 Tracevv((stderr,(char*)"%c", s->window[s->strstart-1])); 01446 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 01447 s->match_available = 0; 01448 } 01449 FLUSH_BLOCK(s, flush == Z_FINISH); 01450 return flush == Z_FINISH ? finish_done : block_done; 01451 }
local block_state deflate_stored | ( | deflate_state * | s, | |
int | flush | |||
) |
Definition at line 1173 of file deflate.cc.
References fill_window(), FLUSH_BLOCK, and need_more.
01174 { 01175 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited 01176 * to pending_buf_size, and each stored block has a 5 byte header: 01177 */ 01178 ulg max_block_size = 0xffff; 01179 ulg max_start; 01180 01181 if (max_block_size > s->pending_buf_size - 5) { 01182 max_block_size = s->pending_buf_size - 5; 01183 } 01184 01185 /* Copy as much as possible from input to output: */ 01186 for (;;) { 01187 /* Fill the window as much as possible: */ 01188 if (s->lookahead <= 1) { 01189 01190 Assert(s->strstart < s->w_size+MAX_DIST(s) || 01191 s->block_start >= (long)s->w_size, (char*)"slide too late"); 01192 01193 fill_window(s); 01194 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; 01195 01196 if (s->lookahead == 0) break; /* flush the current block */ 01197 } 01198 Assert(s->block_start >= 0L, (char*)"block gone"); 01199 01200 s->strstart += s->lookahead; 01201 s->lookahead = 0; 01202 01203 /* Emit a stored block if pending_buf will be full: */ 01204 max_start = s->block_start + max_block_size; 01205 if (s->strstart == 0 || (ulg)s->strstart >= max_start) { 01206 /* strstart == 0 is possible when wraparound on 16-bit machine */ 01207 s->lookahead = (uInt)(s->strstart - max_start); 01208 s->strstart = (uInt)max_start; 01209 FLUSH_BLOCK(s, 0); 01210 } 01211 /* Flush if we may have to slide, otherwise block_start may become 01212 * negative and the data will be gone: 01213 */ 01214 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { 01215 FLUSH_BLOCK(s, 0); 01216 } 01217 } 01218 FLUSH_BLOCK(s, flush == Z_FINISH); 01219 return flush == Z_FINISH ? finish_done : block_done; 01220 }
uLong ZEXPORT deflateBound | ( | z_streamp | strm, | |
uLong | sourceLen | |||
) |
Definition at line 438 of file deflate.cc.
References compressBound().
00439 { 00440 deflate_state *s; 00441 uLong destLen; 00442 00443 /* conservative upper bound */ 00444 destLen = sourceLen + 00445 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; 00446 00447 /* if can't get parameters, return conservative bound */ 00448 if (strm == Z_NULL || strm->state == Z_NULL) 00449 return destLen; 00450 00451 /* if not default parameters, return conservative bound */ 00452 s = strm->state; 00453 if (s->w_bits != 15 || s->hash_bits != 8 + 7) 00454 return destLen; 00455 00456 /* default settings: return tight bound for that case */ 00457 return compressBound(sourceLen); 00458 }
int ZEXPORT deflateCopy | ( | z_streamp | dest, | |
z_streamp | source | |||
) |
Definition at line 699 of file deflate.cc.
References deflateEnd(), and zmemcpy().
00700 { 00701 #ifdef MAXSEG_64K 00702 return Z_STREAM_ERROR; 00703 #else 00704 deflate_state *ds; 00705 deflate_state *ss; 00706 ushf *overlay; 00707 00708 00709 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 00710 return Z_STREAM_ERROR; 00711 } 00712 00713 ss = source->state; 00714 00715 *dest = *source; 00716 00717 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); 00718 if (ds == Z_NULL) return Z_MEM_ERROR; 00719 dest->state = (struct internal_state FAR *) ds; 00720 *ds = *ss; 00721 ds->strm = dest; 00722 00723 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); 00724 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); 00725 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); 00726 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); 00727 ds->pending_buf = (uchf *) overlay; 00728 00729 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || 00730 ds->pending_buf == Z_NULL) { 00731 deflateEnd (dest); 00732 return Z_MEM_ERROR; 00733 } 00734 /* following zmemcpy do not work for 16-bit MSDOS */ 00735 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); 00736 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); 00737 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); 00738 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); 00739 00740 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); 00741 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); 00742 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; 00743 00744 ds->l_desc.dyn_tree = ds->dyn_ltree; 00745 ds->d_desc.dyn_tree = ds->dyn_dtree; 00746 ds->bl_desc.dyn_tree = ds->bl_tree; 00747 00748 return Z_OK; 00749 #endif /* MAXSEG_64K */ 00750 }
int ZEXPORT deflateEnd | ( | z_streamp | strm | ) |
Definition at line 670 of file deflate.cc.
Referenced by compress2(), deflateCopy(), and deflateInit2_().
00671 { 00672 int status; 00673 00674 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 00675 00676 status = strm->state->status; 00677 if (status != INIT_STATE && status != BUSY_STATE && 00678 status != FINISH_STATE) { 00679 return Z_STREAM_ERROR; 00680 } 00681 00682 /* Deallocate in reverse order of allocations: */ 00683 TRY_FREE(strm, strm->state->pending_buf); 00684 TRY_FREE(strm, strm->state->head); 00685 TRY_FREE(strm, strm->state->prev); 00686 TRY_FREE(strm, strm->state->window); 00687 00688 ZFREE(strm, strm->state); 00689 strm->state = Z_NULL; 00690 00691 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 00692 }
int ZEXPORT deflateInit2_ | ( | z_streamp | strm, | |
int | level, | |||
int | method, | |||
int | windowBits, | |||
int | memLevel, | |||
int | strategy, | |||
const char * | version, | |||
int | stream_size | |||
) |
Definition at line 212 of file deflate.cc.
References deflateEnd(), deflateReset(), zcalloc(), and zcfree().
Referenced by deflateInit_().
00214 { 00215 deflate_state *s; 00216 int wrap = 1; 00217 static const char my_version[] = ZLIB_VERSION; 00218 00219 ushf *overlay; 00220 /* We overlay pending_buf and d_buf+l_buf. This works since the average 00221 * output size for (length,distance) codes is <= 24 bits. 00222 */ 00223 00224 if (version == Z_NULL || version[0] != my_version[0] || 00225 stream_size != sizeof(z_stream)) { 00226 return Z_VERSION_ERROR; 00227 } 00228 if (strm == Z_NULL) return Z_STREAM_ERROR; 00229 00230 strm->msg = Z_NULL; 00231 if (strm->zalloc == (alloc_func)0) { 00232 strm->zalloc = zcalloc; 00233 strm->opaque = (voidpf)0; 00234 } 00235 if (strm->zfree == (free_func)0) strm->zfree = zcfree; 00236 00237 #ifdef FASTEST 00238 if (level != 0) level = 1; 00239 #else 00240 if (level == Z_DEFAULT_COMPRESSION) level = 6; 00241 #endif 00242 00243 if (windowBits < 0) { /* suppress zlib wrapper */ 00244 wrap = 0; 00245 windowBits = -windowBits; 00246 } 00247 #ifdef GZIP 00248 else if (windowBits > 15) { 00249 wrap = 2; /* write gzip wrapper instead */ 00250 windowBits -= 16; 00251 } 00252 #endif 00253 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || 00254 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || 00255 strategy < 0 || strategy > Z_RLE) { 00256 return Z_STREAM_ERROR; 00257 } 00258 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ 00259 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); 00260 if (s == Z_NULL) return Z_MEM_ERROR; 00261 strm->state = (struct internal_state FAR *)s; 00262 s->strm = strm; 00263 00264 s->wrap = wrap; 00265 s->w_bits = windowBits; 00266 s->w_size = 1 << s->w_bits; 00267 s->w_mask = s->w_size - 1; 00268 00269 s->hash_bits = memLevel + 7; 00270 s->hash_size = 1 << s->hash_bits; 00271 s->hash_mask = s->hash_size - 1; 00272 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); 00273 00274 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); 00275 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); 00276 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); 00277 00278 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ 00279 00280 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); 00281 s->pending_buf = (uchf *) overlay; 00282 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); 00283 00284 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || 00285 s->pending_buf == Z_NULL) { 00286 s->status = FINISH_STATE; 00287 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); 00288 deflateEnd (strm); 00289 return Z_MEM_ERROR; 00290 } 00291 s->d_buf = overlay + s->lit_bufsize/sizeof(ush); 00292 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; 00293 00294 s->level = level; 00295 s->strategy = strategy; 00296 s->method = (Byte)method; 00297 00298 return deflateReset(strm); 00299 }
int ZEXPORT deflateInit_ | ( | z_streamp | strm, | |
int | level, | |||
const char * | version, | |||
int | stream_size | |||
) |
Definition at line 204 of file deflate.cc.
References deflateInit2_().
00205 { 00206 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, 00207 Z_DEFAULT_STRATEGY, version, stream_size); 00208 /* To do: ignore strm->next_in if we use it as window */ 00209 }
int ZEXPORT deflateParams | ( | z_streamp | strm, | |
int | level, | |||
int | strategy | |||
) |
Definition at line 387 of file deflate.cc.
References deflate().
00388 { 00389 deflate_state *s; 00390 compress_func func; 00391 int err = Z_OK; 00392 00393 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 00394 s = strm->state; 00395 00396 #ifdef FASTEST 00397 if (level != 0) level = 1; 00398 #else 00399 if (level == Z_DEFAULT_COMPRESSION) level = 6; 00400 #endif 00401 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_RLE) { 00402 return Z_STREAM_ERROR; 00403 } 00404 func = configuration_table[s->level].func; 00405 00406 if (func != configuration_table[level].func && strm->total_in != 0) { 00407 /* Flush the last buffer: */ 00408 err = deflate(strm, Z_PARTIAL_FLUSH); 00409 } 00410 if (s->level != level) { 00411 s->level = level; 00412 s->max_lazy_match = configuration_table[level].max_lazy; 00413 s->good_match = configuration_table[level].good_length; 00414 s->nice_match = configuration_table[level].nice_length; 00415 s->max_chain_length = configuration_table[level].max_chain; 00416 } 00417 s->strategy = strategy; 00418 return err; 00419 }
int ZEXPORT deflatePrime | ( | z_streamp | strm, | |
int | bits, | |||
int | value | |||
) |
Definition at line 378 of file deflate.cc.
00379 { 00380 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 00381 strm->state->bi_valid = bits; 00382 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); 00383 return Z_OK; 00384 }
int ZEXPORT deflateReset | ( | z_streamp | strm | ) |
Definition at line 343 of file deflate.cc.
References _tr_init(), adler32(), crc32(), and lm_init().
Referenced by deflateInit2_().
00344 { 00345 deflate_state *s; 00346 00347 if (strm == Z_NULL || strm->state == Z_NULL || 00348 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { 00349 return Z_STREAM_ERROR; 00350 } 00351 00352 strm->total_in = strm->total_out = 0; 00353 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ 00354 strm->data_type = Z_UNKNOWN; 00355 00356 s = (deflate_state *)strm->state; 00357 s->pending = 0; 00358 s->pending_out = s->pending_buf; 00359 00360 if (s->wrap < 0) { 00361 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ 00362 } 00363 s->status = s->wrap ? INIT_STATE : BUSY_STATE; 00364 strm->adler = 00365 #ifdef GZIP 00366 s->wrap == 2 ? crc32(0L, Z_NULL, 0) : 00367 #endif 00368 adler32(0L, Z_NULL, 0); 00369 s->last_flush = Z_NO_FLUSH; 00370 00371 _tr_init(s); 00372 lm_init(s); 00373 00374 return Z_OK; 00375 }
int ZEXPORT deflateSetDictionary | ( | z_streamp | strm, | |
const Bytef * | dictionary, | |||
uInt | dictLength | |||
) |
Definition at line 302 of file deflate.cc.
References adler32(), INSERT_STRING, CLHEP::detail::n, UPDATE_HASH, and zmemcpy().
00303 { 00304 deflate_state *s; 00305 uInt length = dictLength; 00306 uInt n; 00307 IPos hash_head = 0; 00308 00309 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || 00310 strm->state->wrap == 2 || 00311 (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) 00312 return Z_STREAM_ERROR; 00313 00314 s = strm->state; 00315 if (s->wrap) 00316 strm->adler = adler32(strm->adler, dictionary, dictLength); 00317 00318 if (length < MIN_MATCH) return Z_OK; 00319 if (length > MAX_DIST(s)) { 00320 length = MAX_DIST(s); 00321 #ifndef USE_DICT_HEAD 00322 dictionary += dictLength - length; /* use the tail of the dictionary */ 00323 #endif 00324 } 00325 zmemcpy(s->window, dictionary, length); 00326 s->strstart = length; 00327 s->block_start = (long)length; 00328 00329 /* Insert all strings in the hash table (except for the last two bytes). 00330 * s->lookahead stays null, so s->ins_h will be recomputed at the next 00331 * call of fill_window. 00332 */ 00333 s->ins_h = s->window[0]; 00334 UPDATE_HASH(s, s->ins_h, s->window[1]); 00335 for (n = 0; n <= length - MIN_MATCH; n++) { 00336 INSERT_STRING(s, n, hash_head); 00337 } 00338 if (hash_head) hash_head = 0; /* to make compiler happy */ 00339 return Z_OK; 00340 }
local void fill_window | ( | deflate_state * | s | ) |
Definition at line 1051 of file deflate.cc.
References MIN_LOOKAHEAD, CLHEP::detail::n, NIL, read_buf(), times, UPDATE_HASH, and zmemcpy().
Referenced by deflate_fast(), deflate_slow(), and deflate_stored().
01052 { 01053 register unsigned n, m; 01054 register Posf *p; 01055 unsigned more; /* Amount of free space at the end of the window. */ 01056 uInt wsize = s->w_size; 01057 01058 do { 01059 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); 01060 01061 /* Deal with !@#$% 64K limit: */ 01062 if (sizeof(int) <= 2) { 01063 if (more == 0 && s->strstart == 0 && s->lookahead == 0) { 01064 more = wsize; 01065 01066 } else if (more == (unsigned)(-1)) { 01067 /* Very unlikely, but possible on 16 bit machine if 01068 * strstart == 0 && lookahead == 1 (input done a byte at time) 01069 */ 01070 more--; 01071 } 01072 } 01073 01074 /* If the window is almost full and there is insufficient lookahead, 01075 * move the upper half to the lower one to make room in the upper half. 01076 */ 01077 if (s->strstart >= wsize+MAX_DIST(s)) { 01078 01079 zmemcpy(s->window, s->window+wsize, (unsigned)wsize); 01080 s->match_start -= wsize; 01081 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ 01082 s->block_start -= (long) wsize; 01083 01084 /* Slide the hash table (could be avoided with 32 bit values 01085 at the expense of memory usage). We slide even when level == 0 01086 to keep the hash table consistent if we switch back to level > 0 01087 later. (Using level 0 permanently is not an optimal usage of 01088 zlib, so we don't care about this pathological case.) 01089 */ 01090 n = s->hash_size; 01091 p = &s->head[n]; 01092 do { 01093 m = *--p; 01094 *p = (Pos)(m >= wsize ? m-wsize : NIL); 01095 } while (--n); 01096 01097 n = wsize; 01098 #ifndef FASTEST 01099 p = &s->prev[n]; 01100 do { 01101 m = *--p; 01102 *p = (Pos)(m >= wsize ? m-wsize : NIL); 01103 /* If n is not on any hash chain, prev[n] is garbage but 01104 * its value will never be used. 01105 */ 01106 } while (--n); 01107 #endif 01108 more += wsize; 01109 } 01110 if (s->strm->avail_in == 0) return; 01111 01112 /* If there was no sliding: 01113 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && 01114 * more == window_size - lookahead - strstart 01115 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) 01116 * => more >= window_size - 2*WSIZE + 2 01117 * In the BIG_MEM or MMAP case (not yet supported), 01118 * window_size == input_size + MIN_LOOKAHEAD && 01119 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. 01120 * Otherwise, window_size == 2*WSIZE so more >= 2. 01121 * If there was sliding, more >= WSIZE. So in all cases, more >= 2. 01122 */ 01123 Assert(more >= 2, (char*)"more < 2"); 01124 01125 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); 01126 s->lookahead += n; 01127 01128 /* Initialize the hash value now that we have some input: */ 01129 if (s->lookahead >= MIN_MATCH) { 01130 s->ins_h = s->window[s->strstart]; 01131 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 01132 #if MIN_MATCH != 3 01133 Call UPDATE_HASH() MIN_MATCH-3 more times 01134 #endif 01135 } 01136 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, 01137 * but this is not important since only literal bytes will be emitted. 01138 */ 01139 01140 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); 01141 }
local void flush_pending | ( | z_streamp | strm | ) |
Definition at line 477 of file deflate.cc.
References zmemcpy().
Referenced by deflate().
00478 { 00479 unsigned len = strm->state->pending; 00480 00481 if (len > strm->avail_out) len = strm->avail_out; 00482 if (len == 0) return; 00483 00484 zmemcpy(strm->next_out, strm->state->pending_out, len); 00485 strm->next_out += len; 00486 strm->state->pending_out += len; 00487 strm->total_out += len; 00488 strm->avail_out -= len; 00489 strm->state->pending -= len; 00490 if (strm->state->pending == 0) { 00491 strm->state->pending_out = strm->state->pending_buf; 00492 } 00493 }
local void lm_init | ( | deflate_state * | s | ) |
Definition at line 786 of file deflate.cc.
References CLEAR_HASH.
Referenced by deflateReset().
00787 { 00788 s->window_size = (ulg)2L*s->w_size; 00789 00790 CLEAR_HASH(s); 00791 00792 /* Set the default configuration parameters: 00793 */ 00794 s->max_lazy_match = configuration_table[s->level].max_lazy; 00795 s->good_match = configuration_table[s->level].good_length; 00796 s->nice_match = configuration_table[s->level].nice_length; 00797 s->max_chain_length = configuration_table[s->level].max_chain; 00798 00799 s->strstart = 0; 00800 s->block_start = 0L; 00801 s->lookahead = 0; 00802 s->match_length = s->prev_length = MIN_MATCH-1; 00803 s->match_available = 0; 00804 s->ins_h = 0; 00805 #ifdef ASMV 00806 match_init(); /* initialize the asm code */ 00807 #endif 00808 }
local uInt longest_match | ( | deflate_state * | s, | |
IPos | cur_match | |||
) |
Definition at line 824 of file deflate.cc.
References MIN_LOOKAHEAD, and NIL.
00825 { 00826 unsigned chain_length = s->max_chain_length;/* max hash chain length */ 00827 register Bytef *scan = s->window + s->strstart; /* current string */ 00828 register Bytef *match; /* matched string */ 00829 register int len; /* length of current match */ 00830 int best_len = s->prev_length; /* best match length so far */ 00831 int nice_match = s->nice_match; /* stop if match long enough */ 00832 IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 00833 s->strstart - (IPos)MAX_DIST(s) : NIL; 00834 /* Stop when cur_match becomes <= limit. To simplify the code, 00835 * we prevent matches with the string of window index 0. 00836 */ 00837 Posf *prev = s->prev; 00838 uInt wmask = s->w_mask; 00839 00840 #ifdef UNALIGNED_OK 00841 /* Compare two bytes at a time. Note: this is not always beneficial. 00842 * Try with and without -DUNALIGNED_OK to check. 00843 */ 00844 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; 00845 register ush scan_start = *(ushf*)scan; 00846 register ush scan_end = *(ushf*)(scan+best_len-1); 00847 #else 00848 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 00849 register Byte scan_end1 = scan[best_len-1]; 00850 register Byte scan_end = scan[best_len]; 00851 #endif 00852 00853 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 00854 * It is easy to get rid of this optimization if necessary. 00855 */ 00856 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, (char*)"Code too clever"); 00857 00858 /* Do not waste too much time if we already have a good match: */ 00859 if (s->prev_length >= s->good_match) { 00860 chain_length >>= 2; 00861 } 00862 /* Do not look for matches beyond the end of the input. This is necessary 00863 * to make deflate deterministic. 00864 */ 00865 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 00866 00867 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, (char*)"need lookahead"); 00868 00869 do { 00870 Assert(cur_match < s->strstart, (char*)"no future"); 00871 match = s->window + cur_match; 00872 00873 /* Skip to next match if the match length cannot increase 00874 * or if the match length is less than 2: 00875 */ 00876 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) 00877 /* This code assumes sizeof(unsigned short) == 2. Do not use 00878 * UNALIGNED_OK if your compiler uses a different size. 00879 */ 00880 if (*(ushf*)(match+best_len-1) != scan_end || 00881 *(ushf*)match != scan_start) continue; 00882 00883 /* It is not necessary to compare scan[2] and match[2] since they are 00884 * always equal when the other bytes match, given that the hash keys 00885 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at 00886 * strstart+3, +5, ... up to strstart+257. We check for insufficient 00887 * lookahead only every 4th comparison; the 128th check will be made 00888 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is 00889 * necessary to put more guard bytes at the end of the window, or 00890 * to check more often for insufficient lookahead. 00891 */ 00892 Assert(scan[2] == match[2], (char*)"scan[2]?"); 00893 scan++, match++; 00894 do { 00895 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && 00896 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 00897 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 00898 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 00899 scan < strend); 00900 /* The funny "do {}" generates better code on most compilers */ 00901 00902 /* Here, scan <= window+strstart+257 */ 00903 Assert(scan <= s->window+(unsigned)(s->window_size-1), (char*)"wild scan"); 00904 if (*scan == *match) scan++; 00905 00906 len = (MAX_MATCH - 1) - (int)(strend-scan); 00907 scan = strend - (MAX_MATCH-1); 00908 00909 #else /* UNALIGNED_OK */ 00910 00911 if (match[best_len] != scan_end || 00912 match[best_len-1] != scan_end1 || 00913 *match != *scan || 00914 *++match != scan[1]) continue; 00915 00916 /* The check at best_len-1 can be removed because it will be made 00917 * again later. (This heuristic is not always a win.) 00918 * It is not necessary to compare scan[2] and match[2] since they 00919 * are always equal when the other bytes match, given that 00920 * the hash keys are equal and that HASH_BITS >= 8. 00921 */ 00922 scan += 2, match++; 00923 Assert(*scan == *match, (char*)"match[2]?"); 00924 00925 /* We check for insufficient lookahead only every 8th comparison; 00926 * the 256th check will be made at strstart+258. 00927 */ 00928 do { 00929 } while (*++scan == *++match && *++scan == *++match && 00930 *++scan == *++match && *++scan == *++match && 00931 *++scan == *++match && *++scan == *++match && 00932 *++scan == *++match && *++scan == *++match && 00933 scan < strend); 00934 00935 Assert(scan <= s->window+(unsigned)(s->window_size-1), (char*)"wild scan"); 00936 00937 len = MAX_MATCH - (int)(strend - scan); 00938 scan = strend - MAX_MATCH; 00939 00940 #endif /* UNALIGNED_OK */ 00941 00942 if (len > best_len) { 00943 s->match_start = cur_match; 00944 best_len = len; 00945 if (len >= nice_match) break; 00946 #ifdef UNALIGNED_OK 00947 scan_end = *(ushf*)(scan+best_len-1); 00948 #else 00949 scan_end1 = scan[best_len-1]; 00950 scan_end = scan[best_len]; 00951 #endif 00952 } 00953 } while ((cur_match = prev[cur_match & wmask]) > limit 00954 && --chain_length != 0); 00955 00956 if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 00957 return s->lookahead; 00958 }
local uInt longest_match_fast | ( | deflate_state * | s, | |
IPos | cur_match | |||
) |
Definition at line 965 of file deflate.cc.
References MIN_LOOKAHEAD.
00966 { 00967 register Bytef *scan = s->window + s->strstart; /* current string */ 00968 register Bytef *match; /* matched string */ 00969 register int len; /* length of current match */ 00970 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 00971 00972 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 00973 * It is easy to get rid of this optimization if necessary. 00974 */ 00975 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, (char*)"Code too clever"); 00976 00977 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, (char*)"need lookahead"); 00978 00979 Assert(cur_match < s->strstart, (char*)"no future"); 00980 00981 match = s->window + cur_match; 00982 00983 /* Return failure if the match length is less than 2: 00984 */ 00985 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; 00986 00987 /* The check at best_len-1 can be removed because it will be made 00988 * again later. (This heuristic is not always a win.) 00989 * It is not necessary to compare scan[2] and match[2] since they 00990 * are always equal when the other bytes match, given that 00991 * the hash keys are equal and that HASH_BITS >= 8. 00992 */ 00993 scan += 2, match += 2; 00994 Assert(*scan == *match, (char*)"match[2]?"); 00995 00996 /* We check for insufficient lookahead only every 8th comparison; 00997 * the 256th check will be made at strstart+258. 00998 */ 00999 do { 01000 } while (*++scan == *++match && *++scan == *++match && 01001 *++scan == *++match && *++scan == *++match && 01002 *++scan == *++match && *++scan == *++match && 01003 *++scan == *++match && *++scan == *++match && 01004 scan < strend); 01005 01006 Assert(scan <= s->window+(unsigned)(s->window_size-1), (char*)"wild scan"); 01007 01008 len = MAX_MATCH - (int)(strend - scan); 01009 01010 if (len < MIN_MATCH) return MIN_MATCH - 1; 01011 01012 s->match_start = cur_match; 01013 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; 01014 }
local uInt longest_match OF | ( | (deflate_state *s, IPos cur_match) | ) |
local int read_buf OF | ( | (z_streamp strm, Bytef *buf, unsigned size) | ) |
local void flush_pending OF | ( | (z_streamp strm) | ) |
local void putShortMSB OF | ( | (deflate_state *s, uInt b) | ) |
local block_state deflate_stored OF | ( | (deflate_state *s, int flush) | ) |
local void fill_window OF | ( | (deflate_state *s) | ) |
local void putShortMSB | ( | deflate_state * | s, | |
uInt | b | |||
) |
local int read_buf | ( | z_streamp | strm, | |
Bytef * | buf, | |||
unsigned | size | |||
) |
Definition at line 759 of file deflate.cc.
References adler32(), crc32(), and zmemcpy().
Referenced by fill_window().
00760 { 00761 unsigned len = strm->avail_in; 00762 00763 if (len > size) len = size; 00764 if (len == 0) return 0; 00765 00766 strm->avail_in -= len; 00767 00768 if (strm->state->wrap == 1) { 00769 strm->adler = adler32(strm->adler, strm->next_in, len); 00770 } 00771 #ifdef GZIP 00772 else if (strm->state->wrap == 2) { 00773 strm->adler = crc32(strm->adler, strm->next_in, len); 00774 } 00775 #endif 00776 zmemcpy(buf, strm->next_in, len); 00777 strm->next_in += len; 00778 strm->total_in += len; 00779 00780 return (int)len; 00781 }
local const config configuration_table[10] |
Initial value:
{ {0, 0, 0, 0, deflate_stored}, {4, 4, 8, 4, deflate_fast}, {4, 5, 16, 8, deflate_fast}, {4, 6, 32, 32, deflate_fast}, {4, 4, 16, 16, deflate_slow}, {8, 16, 32, 32, deflate_slow}, {8, 16, 128, 128, deflate_slow}, {8, 32, 128, 256, deflate_slow}, {32, 128, 258, 1024, deflate_slow}, {32, 258, 258, 4096, deflate_slow}}
Definition at line 137 of file deflate.cc.
const char deflate_copyright[] |
Initial value:
" deflate 1.2.2 Copyright 1995-2004 Jean-loup Gailly "
Definition at line 54 of file deflate.cc.