1168404Spjd/* 2168404Spjd * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 3168404Spjd * Use is subject to license terms. 4168404Spjd */ 5168404Spjd 6168404Spjd/* deflate.c -- compress data using the deflation algorithm 7168404Spjd * Copyright (C) 1995-2005 Jean-loup Gailly. 8168404Spjd * For conditions of distribution and use, see copyright notice in zlib.h 9168404Spjd */ 10168404Spjd 11168404Spjd#pragma ident "%Z%%M% %I% %E% SMI" 12168404Spjd 13168404Spjd/* 14168404Spjd * ALGORITHM 15168404Spjd * 16168404Spjd * The "deflation" process depends on being able to identify portions 17168404Spjd * of the input text which are identical to earlier input (within a 18168404Spjd * sliding window trailing behind the input currently being processed). 19168404Spjd * 20168404Spjd * The most straightforward technique turns out to be the fastest for 21168404Spjd * most input files: try all possible matches and select the longest. 22168404Spjd * The key feature of this algorithm is that insertions into the string 23168404Spjd * dictionary are very simple and thus fast, and deletions are avoided 24168404Spjd * completely. Insertions are performed at each input character, whereas 25168404Spjd * string matches are performed only when the previous match ends. So it 26168404Spjd * is preferable to spend more time in matches to allow very fast string 27168404Spjd * insertions and avoid deletions. The matching algorithm for small 28168404Spjd * strings is inspired from that of Rabin & Karp. A brute force approach 29168404Spjd * is used to find longer strings when a small match has been found. 30168404Spjd * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze 31168404Spjd * (by Leonid Broukhis). 32168404Spjd * A previous version of this file used a more sophisticated algorithm 33168404Spjd * (by Fiala and Greene) which is guaranteed to run in linear amortized 34168404Spjd * time, but has a larger average cost, uses more memory and is patented. 35168404Spjd * However the F&G algorithm may be faster for some highly redundant 36168404Spjd * files if the parameter max_chain_length (described below) is too large. 37168404Spjd * 38168404Spjd * ACKNOWLEDGEMENTS 39168404Spjd * 40168404Spjd * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and 41168404Spjd * I found it in 'freeze' written by Leonid Broukhis. 42168404Spjd * Thanks to many people for bug reports and testing. 43168404Spjd * 44168404Spjd * REFERENCES 45168404Spjd * 46168404Spjd * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". 47168404Spjd * Available in http://www.ietf.org/rfc/rfc1951.txt 48168404Spjd * 49168404Spjd * A description of the Rabin and Karp algorithm is given in the book 50168404Spjd * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. 51168404Spjd * 52168404Spjd * Fiala,E.R., and Greene,D.H. 53168404Spjd * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 54168404Spjd * 55168404Spjd */ 56168404Spjd 57168404Spjd#include "deflate.h" 58168404Spjd 59168404Spjdstatic const char deflate_copyright[] = 60168404Spjd " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; 61168404Spjd/* 62168404Spjd If you use the zlib library in a product, an acknowledgment is welcome 63168404Spjd in the documentation of your product. If for some reason you cannot 64168404Spjd include such an acknowledgment, I would appreciate that you keep this 65168404Spjd copyright string in the executable of your product. 66168404Spjd */ 67168404Spjd 68168404Spjd/* =========================================================================== 69168404Spjd * Function prototypes. 70168404Spjd */ 71168404Spjdtypedef enum { 72168404Spjd need_more, /* block not completed, need more input or more output */ 73168404Spjd block_done, /* block flush performed */ 74168404Spjd finish_started, /* finish started, need only more output at next deflate */ 75168404Spjd finish_done /* finish done, accept no more input or output */ 76168404Spjd} block_state; 77168404Spjd 78168404Spjdtypedef block_state (*compress_func) OF((deflate_state *s, int flush)); 79168404Spjd/* Compression function. Returns the block state after the call. */ 80168404Spjd 81168404Spjdlocal void fill_window OF((deflate_state *s)); 82168404Spjdlocal block_state deflate_stored OF((deflate_state *s, int flush)); 83168404Spjdlocal block_state deflate_fast OF((deflate_state *s, int flush)); 84168404Spjd#ifndef FASTEST 85168404Spjdlocal block_state deflate_slow OF((deflate_state *s, int flush)); 86168404Spjd#endif 87168404Spjdlocal void lm_init OF((deflate_state *s)); 88168404Spjdlocal void putShortMSB OF((deflate_state *s, uInt b)); 89168404Spjdlocal void flush_pending OF((z_streamp strm)); 90168404Spjdlocal int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); 91168404Spjd#ifndef FASTEST 92168404Spjd#ifdef ASMV 93168404Spjd void match_init OF((void)); /* asm code initialization */ 94168404Spjd uInt longest_match OF((deflate_state *s, IPos cur_match)); 95168404Spjd#else 96168404Spjdlocal uInt longest_match OF((deflate_state *s, IPos cur_match)); 97168404Spjd#endif 98168404Spjd#endif 99168404Spjdlocal uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); 100168404Spjd 101168404Spjd#ifdef DEBUG 102168404Spjdlocal void check_match OF((deflate_state *s, IPos start, IPos match, 103168404Spjd int length)); 104168404Spjd#endif 105168404Spjd 106168404Spjd/* =========================================================================== 107168404Spjd * Local data 108168404Spjd */ 109168404Spjd 110168404Spjd#define NIL 0 111168404Spjd/* Tail of hash chains */ 112168404Spjd 113168404Spjd#ifndef TOO_FAR 114168404Spjd# define TOO_FAR 4096 115168404Spjd#endif 116168404Spjd/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ 117168404Spjd 118168404Spjd#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) 119168404Spjd/* Minimum amount of lookahead, except at the end of the input file. 120168404Spjd * See deflate.c for comments about the MIN_MATCH+1. 121168404Spjd */ 122168404Spjd 123168404Spjd/* Values for max_lazy_match, good_match and max_chain_length, depending on 124168404Spjd * the desired pack level (0..9). The values given below have been tuned to 125168404Spjd * exclude worst case performance for pathological files. Better values may be 126168404Spjd * found for specific files. 127168404Spjd */ 128168404Spjdtypedef struct config_s { 129168404Spjd ush good_length; /* reduce lazy search above this match length */ 130168404Spjd ush max_lazy; /* do not perform lazy search above this match length */ 131168404Spjd ush nice_length; /* quit search above this match length */ 132168404Spjd ush max_chain; 133168404Spjd compress_func func; 134168404Spjd} config; 135168404Spjd 136168404Spjd#ifdef FASTEST 137168404Spjdlocal const config configuration_table[2] = { 138168404Spjd/* good lazy nice chain */ 139168404Spjd/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 140168404Spjd/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ 141168404Spjd#else 142168404Spjdlocal const config configuration_table[10] = { 143168404Spjd/* good lazy nice chain */ 144168404Spjd/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 145168404Spjd/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ 146168404Spjd/* 2 */ {4, 5, 16, 8, deflate_fast}, 147168404Spjd/* 3 */ {4, 6, 32, 32, deflate_fast}, 148168404Spjd 149168404Spjd/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ 150168404Spjd/* 5 */ {8, 16, 32, 32, deflate_slow}, 151168404Spjd/* 6 */ {8, 16, 128, 128, deflate_slow}, 152168404Spjd/* 7 */ {8, 32, 128, 256, deflate_slow}, 153168404Spjd/* 8 */ {32, 128, 258, 1024, deflate_slow}, 154168404Spjd/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ 155168404Spjd#endif 156168404Spjd 157168404Spjd/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 158168404Spjd * For deflate_fast() (levels <= 3) good is ignored and lazy has a different 159168404Spjd * meaning. 160168404Spjd */ 161168404Spjd 162168404Spjd#define EQUAL 0 163168404Spjd/* result of memcmp for equal strings */ 164168404Spjd 165168404Spjd#ifndef NO_DUMMY_DECL 166168404Spjdstruct static_tree_desc_s {int dummy;}; /* for buggy compilers */ 167168404Spjd#endif 168168404Spjd 169168404Spjd/* =========================================================================== 170168404Spjd * Update a hash value with the given input byte 171168404Spjd * IN assertion: all calls to to UPDATE_HASH are made with consecutive 172168404Spjd * input characters, so that a running hash key can be computed from the 173168404Spjd * previous key instead of complete recalculation each time. 174168404Spjd */ 175168404Spjd#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) 176168404Spjd 177168404Spjd 178168404Spjd/* =========================================================================== 179168404Spjd * Insert string str in the dictionary and set match_head to the previous head 180168404Spjd * of the hash chain (the most recent string with same hash key). Return 181168404Spjd * the previous length of the hash chain. 182168404Spjd * If this file is compiled with -DFASTEST, the compression level is forced 183168404Spjd * to 1, and no hash chains are maintained. 184168404Spjd * IN assertion: all calls to to INSERT_STRING are made with consecutive 185168404Spjd * input characters and the first MIN_MATCH bytes of str are valid 186168404Spjd * (except for the last MIN_MATCH-1 bytes of the input file). 187168404Spjd */ 188168404Spjd#ifdef FASTEST 189168404Spjd#define INSERT_STRING(s, str, match_head) \ 190168404Spjd (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 191168404Spjd match_head = s->head[s->ins_h], \ 192168404Spjd s->head[s->ins_h] = (Pos)(str)) 193168404Spjd#else 194168404Spjd#define INSERT_STRING(s, str, match_head) \ 195168404Spjd (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 196168404Spjd match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ 197168404Spjd s->head[s->ins_h] = (Pos)(str)) 198168404Spjd#endif 199168404Spjd 200168404Spjd/* =========================================================================== 201168404Spjd * Initialize the hash table (avoiding 64K overflow for 16 bit systems). 202168404Spjd * prev[] will be initialized on the fly. 203168404Spjd */ 204168404Spjd#define CLEAR_HASH(s) \ 205168404Spjd s->head[s->hash_size-1] = NIL; \ 206168404Spjd (void) zmemzero((Bytef *)s->head, \ 207168404Spjd (unsigned)(s->hash_size-1)*sizeof(*s->head)); 208168404Spjd 209168404Spjd/* ========================================================================= */ 210168404Spjdint ZEXPORT deflateInit_(strm, level, version, stream_size) 211168404Spjd z_streamp strm; 212168404Spjd int level; 213168404Spjd const char *version; 214168404Spjd int stream_size; 215168404Spjd{ 216168404Spjd return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, 217168404Spjd Z_DEFAULT_STRATEGY, version, stream_size); 218168404Spjd /* To do: ignore strm->next_in if we use it as window */ 219168404Spjd} 220168404Spjd 221168404Spjd/* ========================================================================= */ 222168404Spjdint ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, 223168404Spjd version, stream_size) 224168404Spjd z_streamp strm; 225168404Spjd int level; 226168404Spjd int method; 227168404Spjd int windowBits; 228168404Spjd int memLevel; 229168404Spjd int strategy; 230168404Spjd const char *version; 231168404Spjd int stream_size; 232168404Spjd{ 233168404Spjd deflate_state *s; 234168404Spjd int wrap = 1; 235168404Spjd static const char my_version[] = ZLIB_VERSION; 236168404Spjd 237168404Spjd ushf *overlay; 238168404Spjd /* We overlay pending_buf and d_buf+l_buf. This works since the average 239168404Spjd * output size for (length,distance) codes is <= 24 bits. 240168404Spjd */ 241168404Spjd 242168404Spjd if (version == Z_NULL || version[0] != my_version[0] || 243168404Spjd stream_size != sizeof(z_stream)) { 244168404Spjd return Z_VERSION_ERROR; 245168404Spjd } 246168404Spjd if (strm == Z_NULL) return Z_STREAM_ERROR; 247168404Spjd 248168404Spjd strm->msg = Z_NULL; 249168404Spjd if (strm->zalloc == (alloc_func)0) { 250168404Spjd strm->zalloc = zcalloc; 251168404Spjd strm->opaque = (voidpf)0; 252168404Spjd } 253168404Spjd if (strm->zfree == (free_func)0) strm->zfree = zcfree; 254168404Spjd 255168404Spjd#ifdef FASTEST 256168404Spjd if (level != 0) level = 1; 257168404Spjd#else 258168404Spjd if (level == Z_DEFAULT_COMPRESSION) level = 6; 259168404Spjd#endif 260168404Spjd 261168404Spjd if (windowBits < 0) { /* suppress zlib wrapper */ 262168404Spjd wrap = 0; 263168404Spjd windowBits = -windowBits; 264168404Spjd } 265168404Spjd#ifdef GZIP 266168404Spjd else if (windowBits > 15) { 267168404Spjd wrap = 2; /* write gzip wrapper instead */ 268168404Spjd windowBits -= 16; 269168404Spjd } 270168404Spjd#endif 271168404Spjd if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || 272168404Spjd windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || 273168404Spjd strategy < 0 || strategy > Z_FIXED) { 274168404Spjd return Z_STREAM_ERROR; 275168404Spjd } 276168404Spjd if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ 277168404Spjd s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); 278168404Spjd if (s == Z_NULL) return Z_MEM_ERROR; 279168404Spjd strm->state = (struct internal_state FAR *)s; 280168404Spjd s->strm = strm; 281168404Spjd 282168404Spjd s->wrap = wrap; 283168404Spjd s->gzhead = Z_NULL; 284168404Spjd s->w_bits = windowBits; 285168404Spjd s->w_size = 1 << s->w_bits; 286168404Spjd s->w_mask = s->w_size - 1; 287168404Spjd 288168404Spjd s->hash_bits = memLevel + 7; 289168404Spjd s->hash_size = 1 << s->hash_bits; 290168404Spjd s->hash_mask = s->hash_size - 1; 291168404Spjd s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); 292168404Spjd 293168404Spjd s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); 294168404Spjd s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); 295168404Spjd s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); 296168404Spjd 297168404Spjd s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ 298168404Spjd 299168404Spjd overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); 300168404Spjd s->pending_buf = (uchf *) overlay; 301168404Spjd s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); 302168404Spjd 303168404Spjd if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || 304168404Spjd s->pending_buf == Z_NULL) { 305168404Spjd s->status = FINISH_STATE; 306168404Spjd strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); 307168404Spjd (void) deflateEnd (strm); 308168404Spjd return Z_MEM_ERROR; 309168404Spjd } 310168404Spjd s->d_buf = overlay + s->lit_bufsize/sizeof(ush); 311168404Spjd s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; 312168404Spjd 313168404Spjd s->level = level; 314168404Spjd s->strategy = strategy; 315168404Spjd s->method = (Byte)method; 316168404Spjd 317168404Spjd return deflateReset(strm); 318168404Spjd} 319168404Spjd 320168404Spjd/* ========================================================================= */ 321168404Spjdint ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) 322168404Spjd z_streamp strm; 323168404Spjd const Bytef *dictionary; 324168404Spjd uInt dictLength; 325168404Spjd{ 326168404Spjd deflate_state *s; 327168404Spjd uInt length = dictLength; 328168404Spjd uInt n; 329168404Spjd IPos hash_head = 0; 330168404Spjd 331168404Spjd if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || 332168404Spjd strm->state->wrap == 2 || 333168404Spjd (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) 334168404Spjd return Z_STREAM_ERROR; 335168404Spjd 336168404Spjd s = strm->state; 337168404Spjd if (s->wrap) 338168404Spjd strm->adler = adler32(strm->adler, dictionary, dictLength); 339168404Spjd 340168404Spjd if (length < MIN_MATCH) return Z_OK; 341168404Spjd if (length > MAX_DIST(s)) { 342168404Spjd length = MAX_DIST(s); 343168404Spjd dictionary += dictLength - length; /* use the tail of the dictionary */ 344168404Spjd } 345168404Spjd (void) zmemcpy(s->window, dictionary, length); 346168404Spjd s->strstart = length; 347168404Spjd s->block_start = (long)length; 348168404Spjd 349168404Spjd /* Insert all strings in the hash table (except for the last two bytes). 350168404Spjd * s->lookahead stays null, so s->ins_h will be recomputed at the next 351168404Spjd * call of fill_window. 352168404Spjd */ 353168404Spjd s->ins_h = s->window[0]; 354168404Spjd UPDATE_HASH(s, s->ins_h, s->window[1]); 355168404Spjd for (n = 0; n <= length - MIN_MATCH; n++) { 356168404Spjd INSERT_STRING(s, n, hash_head); 357168404Spjd } 358168404Spjd if (hash_head) hash_head = 0; /* to make compiler happy */ 359168404Spjd return Z_OK; 360168404Spjd} 361168404Spjd 362168404Spjd/* ========================================================================= */ 363168404Spjdint ZEXPORT deflateReset (strm) 364168404Spjd z_streamp strm; 365168404Spjd{ 366168404Spjd deflate_state *s; 367168404Spjd 368168404Spjd if (strm == Z_NULL || strm->state == Z_NULL || 369168404Spjd strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { 370168404Spjd return Z_STREAM_ERROR; 371168404Spjd } 372168404Spjd 373168404Spjd strm->total_in = strm->total_out = 0; 374168404Spjd strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ 375168404Spjd strm->data_type = Z_UNKNOWN; 376168404Spjd 377168404Spjd s = (deflate_state *)strm->state; 378168404Spjd s->pending = 0; 379168404Spjd s->pending_out = s->pending_buf; 380168404Spjd 381168404Spjd if (s->wrap < 0) { 382168404Spjd s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ 383168404Spjd } 384168404Spjd s->status = s->wrap ? INIT_STATE : BUSY_STATE; 385168404Spjd strm->adler = 386168404Spjd#ifdef GZIP 387168404Spjd s->wrap == 2 ? crc32(0L, Z_NULL, 0) : 388168404Spjd#endif 389168404Spjd adler32(0L, Z_NULL, 0); 390168404Spjd s->last_flush = Z_NO_FLUSH; 391168404Spjd 392168404Spjd _tr_init(s); 393168404Spjd lm_init(s); 394168404Spjd 395168404Spjd return Z_OK; 396168404Spjd} 397168404Spjd 398168404Spjd/* ========================================================================= */ 399168404Spjdint ZEXPORT deflateSetHeader (strm, head) 400168404Spjd z_streamp strm; 401168404Spjd gz_headerp head; 402168404Spjd{ 403168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 404168404Spjd if (strm->state->wrap != 2) return Z_STREAM_ERROR; 405168404Spjd strm->state->gzhead = head; 406168404Spjd return Z_OK; 407168404Spjd} 408168404Spjd 409168404Spjd/* ========================================================================= */ 410168404Spjdint ZEXPORT deflatePrime (strm, bits, value) 411168404Spjd z_streamp strm; 412168404Spjd int bits; 413168404Spjd int value; 414168404Spjd{ 415168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 416168404Spjd strm->state->bi_valid = bits; 417168404Spjd strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); 418168404Spjd return Z_OK; 419168404Spjd} 420168404Spjd 421168404Spjd/* ========================================================================= */ 422168404Spjdint ZEXPORT deflateParams(strm, level, strategy) 423168404Spjd z_streamp strm; 424168404Spjd int level; 425168404Spjd int strategy; 426168404Spjd{ 427168404Spjd deflate_state *s; 428168404Spjd compress_func func; 429168404Spjd int err = Z_OK; 430168404Spjd 431168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 432168404Spjd s = strm->state; 433168404Spjd 434168404Spjd#ifdef FASTEST 435168404Spjd if (level != 0) level = 1; 436168404Spjd#else 437168404Spjd if (level == Z_DEFAULT_COMPRESSION) level = 6; 438168404Spjd#endif 439168404Spjd if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { 440168404Spjd return Z_STREAM_ERROR; 441168404Spjd } 442168404Spjd func = configuration_table[s->level].func; 443168404Spjd 444168404Spjd if (func != configuration_table[level].func && strm->total_in != 0) { 445168404Spjd /* Flush the last buffer: */ 446168404Spjd err = deflate(strm, Z_PARTIAL_FLUSH); 447168404Spjd } 448168404Spjd if (s->level != level) { 449168404Spjd s->level = level; 450168404Spjd s->max_lazy_match = configuration_table[level].max_lazy; 451168404Spjd s->good_match = configuration_table[level].good_length; 452168404Spjd s->nice_match = configuration_table[level].nice_length; 453168404Spjd s->max_chain_length = configuration_table[level].max_chain; 454168404Spjd } 455168404Spjd s->strategy = strategy; 456168404Spjd return err; 457168404Spjd} 458168404Spjd 459168404Spjd/* ========================================================================= */ 460168404Spjdint ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) 461168404Spjd z_streamp strm; 462168404Spjd int good_length; 463168404Spjd int max_lazy; 464168404Spjd int nice_length; 465168404Spjd int max_chain; 466168404Spjd{ 467168404Spjd deflate_state *s; 468168404Spjd 469168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 470168404Spjd s = strm->state; 471168404Spjd s->good_match = good_length; 472168404Spjd s->max_lazy_match = max_lazy; 473168404Spjd s->nice_match = nice_length; 474168404Spjd s->max_chain_length = max_chain; 475168404Spjd return Z_OK; 476168404Spjd} 477168404Spjd 478168404Spjd/* ========================================================================= 479168404Spjd * For the default windowBits of 15 and memLevel of 8, this function returns 480168404Spjd * a close to exact, as well as small, upper bound on the compressed size. 481168404Spjd * They are coded as constants here for a reason--if the #define's are 482168404Spjd * changed, then this function needs to be changed as well. The return 483168404Spjd * value for 15 and 8 only works for those exact settings. 484168404Spjd * 485168404Spjd * For any setting other than those defaults for windowBits and memLevel, 486168404Spjd * the value returned is a conservative worst case for the maximum expansion 487168404Spjd * resulting from using fixed blocks instead of stored blocks, which deflate 488168404Spjd * can emit on compressed data for some combinations of the parameters. 489168404Spjd * 490168404Spjd * This function could be more sophisticated to provide closer upper bounds 491168404Spjd * for every combination of windowBits and memLevel, as well as wrap. 492168404Spjd * But even the conservative upper bound of about 14% expansion does not 493168404Spjd * seem onerous for output buffer allocation. 494168404Spjd */ 495168404SpjduLong ZEXPORT deflateBound(strm, sourceLen) 496168404Spjd z_streamp strm; 497168404Spjd uLong sourceLen; 498168404Spjd{ 499168404Spjd deflate_state *s; 500168404Spjd uLong destLen; 501168404Spjd 502168404Spjd /* conservative upper bound */ 503168404Spjd destLen = sourceLen + 504168404Spjd ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; 505168404Spjd 506168404Spjd /* if can't get parameters, return conservative bound */ 507168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) 508168404Spjd return destLen; 509168404Spjd 510168404Spjd /* if not default parameters, return conservative bound */ 511168404Spjd s = strm->state; 512168404Spjd if (s->w_bits != 15 || s->hash_bits != 8 + 7) 513168404Spjd return destLen; 514168404Spjd 515168404Spjd /* default settings: return tight bound for that case */ 516168404Spjd return compressBound(sourceLen); 517168404Spjd} 518168404Spjd 519168404Spjd/* ========================================================================= 520168404Spjd * Put a short in the pending buffer. The 16-bit value is put in MSB order. 521168404Spjd * IN assertion: the stream state is correct and there is enough room in 522168404Spjd * pending_buf. 523168404Spjd */ 524168404Spjdlocal void putShortMSB (s, b) 525168404Spjd deflate_state *s; 526168404Spjd uInt b; 527168404Spjd{ 528168404Spjd put_byte(s, (Byte)(b >> 8)); 529168404Spjd put_byte(s, (Byte)(b & 0xff)); 530168404Spjd} 531168404Spjd 532168404Spjd/* ========================================================================= 533168404Spjd * Flush as much pending output as possible. All deflate() output goes 534168404Spjd * through this function so some applications may wish to modify it 535168404Spjd * to avoid allocating a large strm->next_out buffer and copying into it. 536168404Spjd * (See also read_buf()). 537168404Spjd */ 538168404Spjdlocal void flush_pending(strm) 539168404Spjd z_streamp strm; 540168404Spjd{ 541168404Spjd unsigned len = strm->state->pending; 542168404Spjd 543168404Spjd if (len > strm->avail_out) len = strm->avail_out; 544168404Spjd if (len == 0) return; 545168404Spjd 546168404Spjd zmemcpy(strm->next_out, strm->state->pending_out, len); 547168404Spjd strm->next_out += len; 548168404Spjd strm->state->pending_out += len; 549168404Spjd strm->total_out += len; 550168404Spjd strm->avail_out -= len; 551168404Spjd strm->state->pending -= len; 552168404Spjd if (strm->state->pending == 0) { 553168404Spjd strm->state->pending_out = strm->state->pending_buf; 554168404Spjd } 555168404Spjd} 556168404Spjd 557168404Spjd/* ========================================================================= */ 558168404Spjdint ZEXPORT deflate (strm, flush) 559168404Spjd z_streamp strm; 560168404Spjd int flush; 561168404Spjd{ 562168404Spjd int old_flush; /* value of flush param for previous deflate call */ 563168404Spjd deflate_state *s; 564168404Spjd 565168404Spjd if (strm == Z_NULL || strm->state == Z_NULL || 566168404Spjd flush > Z_FINISH || flush < 0) { 567168404Spjd return Z_STREAM_ERROR; 568168404Spjd } 569168404Spjd s = strm->state; 570168404Spjd 571168404Spjd if (strm->next_out == Z_NULL || 572168404Spjd (strm->next_in == Z_NULL && strm->avail_in != 0) || 573168404Spjd (s->status == FINISH_STATE && flush != Z_FINISH)) { 574168404Spjd ERR_RETURN(strm, Z_STREAM_ERROR); 575168404Spjd } 576168404Spjd if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 577168404Spjd 578168404Spjd s->strm = strm; /* just in case */ 579168404Spjd old_flush = s->last_flush; 580168404Spjd s->last_flush = flush; 581168404Spjd 582168404Spjd /* Write the header */ 583168404Spjd if (s->status == INIT_STATE) { 584168404Spjd#ifdef GZIP 585168404Spjd if (s->wrap == 2) { 586168404Spjd strm->adler = crc32(0L, Z_NULL, 0); 587168404Spjd put_byte(s, 31); 588168404Spjd put_byte(s, 139); 589168404Spjd put_byte(s, 8); 590168404Spjd if (s->gzhead == NULL) { 591168404Spjd put_byte(s, 0); 592168404Spjd put_byte(s, 0); 593168404Spjd put_byte(s, 0); 594168404Spjd put_byte(s, 0); 595168404Spjd put_byte(s, 0); 596168404Spjd put_byte(s, s->level == 9 ? 2 : 597168404Spjd (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 598168404Spjd 4 : 0)); 599168404Spjd put_byte(s, OS_CODE); 600168404Spjd s->status = BUSY_STATE; 601168404Spjd } 602168404Spjd else { 603168404Spjd put_byte(s, (s->gzhead->text ? 1 : 0) + 604168404Spjd (s->gzhead->hcrc ? 2 : 0) + 605168404Spjd (s->gzhead->extra == Z_NULL ? 0 : 4) + 606168404Spjd (s->gzhead->name == Z_NULL ? 0 : 8) + 607168404Spjd (s->gzhead->comment == Z_NULL ? 0 : 16) 608168404Spjd ); 609168404Spjd put_byte(s, (Byte)(s->gzhead->time & 0xff)); 610168404Spjd put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); 611168404Spjd put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); 612168404Spjd put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); 613168404Spjd put_byte(s, s->level == 9 ? 2 : 614168404Spjd (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 615168404Spjd 4 : 0)); 616168404Spjd put_byte(s, s->gzhead->os & 0xff); 617168404Spjd if (s->gzhead->extra != NULL) { 618168404Spjd put_byte(s, s->gzhead->extra_len & 0xff); 619168404Spjd put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); 620168404Spjd } 621168404Spjd if (s->gzhead->hcrc) 622168404Spjd strm->adler = crc32(strm->adler, s->pending_buf, 623168404Spjd s->pending); 624168404Spjd s->gzindex = 0; 625168404Spjd s->status = EXTRA_STATE; 626168404Spjd } 627168404Spjd } 628168404Spjd else 629168404Spjd#endif 630168404Spjd { 631168404Spjd uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 632168404Spjd uInt level_flags; 633168404Spjd 634168404Spjd if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 635168404Spjd level_flags = 0; 636168404Spjd else if (s->level < 6) 637168404Spjd level_flags = 1; 638168404Spjd else if (s->level == 6) 639168404Spjd level_flags = 2; 640168404Spjd else 641168404Spjd level_flags = 3; 642168404Spjd header |= (level_flags << 6); 643168404Spjd if (s->strstart != 0) header |= PRESET_DICT; 644168404Spjd header += 31 - (header % 31); 645168404Spjd 646168404Spjd s->status = BUSY_STATE; 647168404Spjd putShortMSB(s, header); 648168404Spjd 649168404Spjd /* Save the adler32 of the preset dictionary: */ 650168404Spjd if (s->strstart != 0) { 651168404Spjd putShortMSB(s, (uInt)(strm->adler >> 16)); 652168404Spjd putShortMSB(s, (uInt)(strm->adler & 0xffff)); 653168404Spjd } 654168404Spjd strm->adler = adler32(0L, Z_NULL, 0); 655168404Spjd } 656168404Spjd } 657168404Spjd#ifdef GZIP 658168404Spjd if (s->status == EXTRA_STATE) { 659168404Spjd if (s->gzhead->extra != NULL) { 660168404Spjd uInt beg = s->pending; /* start of bytes to update crc */ 661168404Spjd 662168404Spjd while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { 663168404Spjd if (s->pending == s->pending_buf_size) { 664168404Spjd if (s->gzhead->hcrc && s->pending > beg) 665168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 666168404Spjd s->pending - beg); 667168404Spjd flush_pending(strm); 668168404Spjd beg = s->pending; 669168404Spjd if (s->pending == s->pending_buf_size) 670168404Spjd break; 671168404Spjd } 672168404Spjd put_byte(s, s->gzhead->extra[s->gzindex]); 673168404Spjd s->gzindex++; 674168404Spjd } 675168404Spjd if (s->gzhead->hcrc && s->pending > beg) 676168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 677168404Spjd s->pending - beg); 678168404Spjd if (s->gzindex == s->gzhead->extra_len) { 679168404Spjd s->gzindex = 0; 680168404Spjd s->status = NAME_STATE; 681168404Spjd } 682168404Spjd } 683168404Spjd else 684168404Spjd s->status = NAME_STATE; 685168404Spjd } 686168404Spjd if (s->status == NAME_STATE) { 687168404Spjd if (s->gzhead->name != NULL) { 688168404Spjd uInt beg = s->pending; /* start of bytes to update crc */ 689168404Spjd int val; 690168404Spjd 691168404Spjd do { 692168404Spjd if (s->pending == s->pending_buf_size) { 693168404Spjd if (s->gzhead->hcrc && s->pending > beg) 694168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 695168404Spjd s->pending - beg); 696168404Spjd flush_pending(strm); 697168404Spjd beg = s->pending; 698168404Spjd if (s->pending == s->pending_buf_size) { 699168404Spjd val = 1; 700168404Spjd break; 701168404Spjd } 702168404Spjd } 703168404Spjd val = s->gzhead->name[s->gzindex++]; 704168404Spjd put_byte(s, val); 705168404Spjd } while (val != 0); 706168404Spjd if (s->gzhead->hcrc && s->pending > beg) 707168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 708168404Spjd s->pending - beg); 709168404Spjd if (val == 0) { 710168404Spjd s->gzindex = 0; 711168404Spjd s->status = COMMENT_STATE; 712168404Spjd } 713168404Spjd } 714168404Spjd else 715168404Spjd s->status = COMMENT_STATE; 716168404Spjd } 717168404Spjd if (s->status == COMMENT_STATE) { 718168404Spjd if (s->gzhead->comment != NULL) { 719168404Spjd uInt beg = s->pending; /* start of bytes to update crc */ 720168404Spjd int val; 721168404Spjd 722168404Spjd do { 723168404Spjd if (s->pending == s->pending_buf_size) { 724168404Spjd if (s->gzhead->hcrc && s->pending > beg) 725168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 726168404Spjd s->pending - beg); 727168404Spjd flush_pending(strm); 728168404Spjd beg = s->pending; 729168404Spjd if (s->pending == s->pending_buf_size) { 730168404Spjd val = 1; 731168404Spjd break; 732168404Spjd } 733168404Spjd } 734168404Spjd val = s->gzhead->comment[s->gzindex++]; 735168404Spjd put_byte(s, val); 736168404Spjd } while (val != 0); 737168404Spjd if (s->gzhead->hcrc && s->pending > beg) 738168404Spjd strm->adler = crc32(strm->adler, s->pending_buf + beg, 739168404Spjd s->pending - beg); 740168404Spjd if (val == 0) 741168404Spjd s->status = HCRC_STATE; 742168404Spjd } 743168404Spjd else 744168404Spjd s->status = HCRC_STATE; 745168404Spjd } 746168404Spjd if (s->status == HCRC_STATE) { 747168404Spjd if (s->gzhead->hcrc) { 748168404Spjd if (s->pending + 2 > s->pending_buf_size) 749168404Spjd flush_pending(strm); 750168404Spjd if (s->pending + 2 <= s->pending_buf_size) { 751168404Spjd put_byte(s, (Byte)(strm->adler & 0xff)); 752168404Spjd put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 753168404Spjd strm->adler = crc32(0L, Z_NULL, 0); 754168404Spjd s->status = BUSY_STATE; 755168404Spjd } 756168404Spjd } 757168404Spjd else 758168404Spjd s->status = BUSY_STATE; 759168404Spjd } 760168404Spjd#endif 761168404Spjd 762168404Spjd /* Flush as much pending output as possible */ 763168404Spjd if (s->pending != 0) { 764168404Spjd flush_pending(strm); 765168404Spjd if (strm->avail_out == 0) { 766168404Spjd /* Since avail_out is 0, deflate will be called again with 767168404Spjd * more output space, but possibly with both pending and 768168404Spjd * avail_in equal to zero. There won't be anything to do, 769168404Spjd * but this is not an error situation so make sure we 770168404Spjd * return OK instead of BUF_ERROR at next call of deflate: 771168404Spjd */ 772168404Spjd s->last_flush = -1; 773168404Spjd return Z_OK; 774168404Spjd } 775168404Spjd 776168404Spjd /* Make sure there is something to do and avoid duplicate consecutive 777168404Spjd * flushes. For repeated and useless calls with Z_FINISH, we keep 778168404Spjd * returning Z_STREAM_END instead of Z_BUF_ERROR. 779168404Spjd */ 780168404Spjd } else if (strm->avail_in == 0 && flush <= old_flush && 781168404Spjd flush != Z_FINISH) { 782168404Spjd ERR_RETURN(strm, Z_BUF_ERROR); 783168404Spjd } 784168404Spjd 785168404Spjd /* User must not provide more input after the first FINISH: */ 786168404Spjd if (s->status == FINISH_STATE && strm->avail_in != 0) { 787168404Spjd ERR_RETURN(strm, Z_BUF_ERROR); 788168404Spjd } 789168404Spjd 790168404Spjd /* Start a new block or continue the current one. 791168404Spjd */ 792168404Spjd if (strm->avail_in != 0 || s->lookahead != 0 || 793168404Spjd (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 794168404Spjd block_state bstate; 795168404Spjd 796168404Spjd bstate = (*(configuration_table[s->level].func))(s, flush); 797168404Spjd 798168404Spjd if (bstate == finish_started || bstate == finish_done) { 799168404Spjd s->status = FINISH_STATE; 800168404Spjd } 801168404Spjd if (bstate == need_more || bstate == finish_started) { 802168404Spjd if (strm->avail_out == 0) { 803168404Spjd s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 804168404Spjd } 805168404Spjd return Z_OK; 806168404Spjd /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 807168404Spjd * of deflate should use the same flush parameter to make sure 808168404Spjd * that the flush is complete. So we don't have to output an 809168404Spjd * empty block here, this will be done at next call. This also 810168404Spjd * ensures that for a very small output buffer, we emit at most 811168404Spjd * one empty block. 812168404Spjd */ 813168404Spjd } 814168404Spjd if (bstate == block_done) { 815168404Spjd if (flush == Z_PARTIAL_FLUSH) { 816168404Spjd _tr_align(s); 817168404Spjd } else { /* FULL_FLUSH or SYNC_FLUSH */ 818168404Spjd _tr_stored_block(s, (char*)0, 0L, 0); 819168404Spjd /* For a full flush, this empty block will be recognized 820168404Spjd * as a special marker by inflate_sync(). 821168404Spjd */ 822168404Spjd if (flush == Z_FULL_FLUSH) { 823168404Spjd CLEAR_HASH(s); /* forget history */ 824168404Spjd } 825168404Spjd } 826168404Spjd flush_pending(strm); 827168404Spjd if (strm->avail_out == 0) { 828168404Spjd s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 829168404Spjd return Z_OK; 830168404Spjd } 831168404Spjd } 832168404Spjd } 833168404Spjd Assert(strm->avail_out > 0, "bug2"); 834168404Spjd 835168404Spjd if (flush != Z_FINISH) return Z_OK; 836168404Spjd if (s->wrap <= 0) return Z_STREAM_END; 837168404Spjd 838168404Spjd /* Write the trailer */ 839168404Spjd#ifdef GZIP 840168404Spjd if (s->wrap == 2) { 841168404Spjd put_byte(s, (Byte)(strm->adler & 0xff)); 842168404Spjd put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 843168404Spjd put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 844168404Spjd put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 845168404Spjd put_byte(s, (Byte)(strm->total_in & 0xff)); 846168404Spjd put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 847168404Spjd put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 848168404Spjd put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 849168404Spjd } 850168404Spjd else 851168404Spjd#endif 852168404Spjd { 853168404Spjd putShortMSB(s, (uInt)(strm->adler >> 16)); 854168404Spjd putShortMSB(s, (uInt)(strm->adler & 0xffff)); 855168404Spjd } 856168404Spjd flush_pending(strm); 857168404Spjd /* If avail_out is zero, the application will call deflate again 858168404Spjd * to flush the rest. 859168404Spjd */ 860168404Spjd if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 861168404Spjd return s->pending != 0 ? Z_OK : Z_STREAM_END; 862168404Spjd} 863168404Spjd 864168404Spjd/* ========================================================================= */ 865168404Spjdint ZEXPORT deflateEnd (strm) 866168404Spjd z_streamp strm; 867168404Spjd{ 868168404Spjd int status; 869168404Spjd 870168404Spjd if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 871168404Spjd 872168404Spjd status = strm->state->status; 873168404Spjd if (status != INIT_STATE && 874168404Spjd status != EXTRA_STATE && 875168404Spjd status != NAME_STATE && 876168404Spjd status != COMMENT_STATE && 877168404Spjd status != HCRC_STATE && 878168404Spjd status != BUSY_STATE && 879168404Spjd status != FINISH_STATE) { 880168404Spjd return Z_STREAM_ERROR; 881168404Spjd } 882168404Spjd 883168404Spjd /* Deallocate in reverse order of allocations: */ 884168404Spjd TRY_FREE(strm, strm->state->pending_buf); 885168404Spjd TRY_FREE(strm, strm->state->head); 886168404Spjd TRY_FREE(strm, strm->state->prev); 887168404Spjd TRY_FREE(strm, strm->state->window); 888168404Spjd 889168404Spjd ZFREE(strm, strm->state); 890168404Spjd strm->state = Z_NULL; 891168404Spjd 892168404Spjd return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 893168404Spjd} 894168404Spjd 895168404Spjd/* ========================================================================= 896168404Spjd * Copy the source state to the destination state. 897168404Spjd * To simplify the source, this is not supported for 16-bit MSDOS (which 898168404Spjd * doesn't have enough memory anyway to duplicate compression states). 899168404Spjd */ 900168404Spjdint ZEXPORT deflateCopy (dest, source) 901168404Spjd z_streamp dest; 902168404Spjd z_streamp source; 903168404Spjd{ 904168404Spjd#ifdef MAXSEG_64K 905168404Spjd return Z_STREAM_ERROR; 906168404Spjd#else 907168404Spjd deflate_state *ds; 908168404Spjd deflate_state *ss; 909168404Spjd ushf *overlay; 910168404Spjd 911168404Spjd 912168404Spjd if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 913168404Spjd return Z_STREAM_ERROR; 914168404Spjd } 915168404Spjd 916168404Spjd ss = source->state; 917168404Spjd 918168404Spjd zmemcpy(dest, source, sizeof(z_stream)); 919168404Spjd 920168404Spjd ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); 921168404Spjd if (ds == Z_NULL) return Z_MEM_ERROR; 922168404Spjd dest->state = (struct internal_state FAR *) ds; 923168404Spjd zmemcpy(ds, ss, sizeof(deflate_state)); 924168404Spjd ds->strm = dest; 925168404Spjd 926168404Spjd ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); 927168404Spjd ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); 928168404Spjd ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); 929168404Spjd overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); 930168404Spjd ds->pending_buf = (uchf *) overlay; 931168404Spjd 932168404Spjd if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || 933168404Spjd ds->pending_buf == Z_NULL) { 934168404Spjd deflateEnd (dest); 935168404Spjd return Z_MEM_ERROR; 936168404Spjd } 937168404Spjd /* following zmemcpy do not work for 16-bit MSDOS */ 938168404Spjd zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); 939168404Spjd zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); 940168404Spjd zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); 941168404Spjd zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); 942168404Spjd 943168404Spjd ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); 944168404Spjd ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); 945168404Spjd ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; 946168404Spjd 947168404Spjd ds->l_desc.dyn_tree = ds->dyn_ltree; 948168404Spjd ds->d_desc.dyn_tree = ds->dyn_dtree; 949168404Spjd ds->bl_desc.dyn_tree = ds->bl_tree; 950168404Spjd 951168404Spjd return Z_OK; 952168404Spjd#endif /* MAXSEG_64K */ 953168404Spjd} 954168404Spjd 955168404Spjd/* =========================================================================== 956168404Spjd * Read a new buffer from the current input stream, update the adler32 957168404Spjd * and total number of bytes read. All deflate() input goes through 958168404Spjd * this function so some applications may wish to modify it to avoid 959168404Spjd * allocating a large strm->next_in buffer and copying from it. 960168404Spjd * (See also flush_pending()). 961168404Spjd */ 962168404Spjdlocal int read_buf(strm, buf, size) 963168404Spjd z_streamp strm; 964168404Spjd Bytef *buf; 965168404Spjd unsigned size; 966168404Spjd{ 967168404Spjd unsigned len = strm->avail_in; 968168404Spjd 969168404Spjd if (len > size) len = size; 970168404Spjd if (len == 0) return 0; 971168404Spjd 972168404Spjd strm->avail_in -= len; 973168404Spjd 974168404Spjd if (strm->state->wrap == 1) { 975168404Spjd strm->adler = adler32(strm->adler, strm->next_in, len); 976168404Spjd } 977168404Spjd#ifdef GZIP 978168404Spjd else if (strm->state->wrap == 2) { 979168404Spjd strm->adler = crc32(strm->adler, strm->next_in, len); 980168404Spjd } 981168404Spjd#endif 982168404Spjd zmemcpy(buf, strm->next_in, len); 983168404Spjd strm->next_in += len; 984168404Spjd strm->total_in += len; 985168404Spjd 986168404Spjd return (int)len; 987168404Spjd} 988168404Spjd 989168404Spjd/* =========================================================================== 990168404Spjd * Initialize the "longest match" routines for a new zlib stream 991168404Spjd */ 992168404Spjdlocal void lm_init (s) 993168404Spjd deflate_state *s; 994168404Spjd{ 995168404Spjd s->window_size = (ulg)2L*s->w_size; 996168404Spjd 997168404Spjd CLEAR_HASH(s); 998168404Spjd 999168404Spjd /* Set the default configuration parameters: 1000168404Spjd */ 1001168404Spjd s->max_lazy_match = configuration_table[s->level].max_lazy; 1002168404Spjd s->good_match = configuration_table[s->level].good_length; 1003168404Spjd s->nice_match = configuration_table[s->level].nice_length; 1004168404Spjd s->max_chain_length = configuration_table[s->level].max_chain; 1005168404Spjd 1006168404Spjd s->strstart = 0; 1007168404Spjd s->block_start = 0L; 1008168404Spjd s->lookahead = 0; 1009168404Spjd s->match_length = s->prev_length = MIN_MATCH-1; 1010168404Spjd s->match_available = 0; 1011168404Spjd s->ins_h = 0; 1012168404Spjd#ifndef FASTEST 1013168404Spjd#ifdef ASMV 1014168404Spjd match_init(); /* initialize the asm code */ 1015168404Spjd#endif 1016168404Spjd#endif 1017168404Spjd} 1018168404Spjd 1019168404Spjd#ifndef FASTEST 1020168404Spjd/* =========================================================================== 1021168404Spjd * Set match_start to the longest match starting at the given string and 1022168404Spjd * return its length. Matches shorter or equal to prev_length are discarded, 1023168404Spjd * in which case the result is equal to prev_length and match_start is 1024168404Spjd * garbage. 1025168404Spjd * IN assertions: cur_match is the head of the hash chain for the current 1026168404Spjd * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 1027168404Spjd * OUT assertion: the match length is not greater than s->lookahead. 1028168404Spjd */ 1029168404Spjd#ifndef ASMV 1030168404Spjd/* For 80x86 and 680x0, an optimized version will be provided in match.asm or 1031168404Spjd * match.S. The code will be functionally equivalent. 1032168404Spjd */ 1033168404Spjdlocal uInt longest_match(s, cur_match) 1034168404Spjd deflate_state *s; 1035168404Spjd IPos cur_match; /* current match */ 1036168404Spjd{ 1037168404Spjd unsigned chain_length = s->max_chain_length;/* max hash chain length */ 1038168404Spjd register Bytef *scan = s->window + s->strstart; /* current string */ 1039168404Spjd register Bytef *match; /* matched string */ 1040168404Spjd register int len; /* length of current match */ 1041168404Spjd int best_len = s->prev_length; /* best match length so far */ 1042168404Spjd int nice_match = s->nice_match; /* stop if match long enough */ 1043168404Spjd IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 1044168404Spjd s->strstart - (IPos)MAX_DIST(s) : NIL; 1045168404Spjd /* Stop when cur_match becomes <= limit. To simplify the code, 1046168404Spjd * we prevent matches with the string of window index 0. 1047168404Spjd */ 1048168404Spjd Posf *prev = s->prev; 1049168404Spjd uInt wmask = s->w_mask; 1050168404Spjd 1051168404Spjd#ifdef UNALIGNED_OK 1052168404Spjd /* Compare two bytes at a time. Note: this is not always beneficial. 1053168404Spjd * Try with and without -DUNALIGNED_OK to check. 1054168404Spjd */ 1055168404Spjd register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; 1056168404Spjd register ush scan_start = *(ushf*)scan; 1057168404Spjd register ush scan_end = *(ushf*)(scan+best_len-1); 1058168404Spjd#else 1059168404Spjd register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1060168404Spjd register Byte scan_end1 = scan[best_len-1]; 1061168404Spjd register Byte scan_end = scan[best_len]; 1062168404Spjd#endif 1063168404Spjd 1064168404Spjd /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1065168404Spjd * It is easy to get rid of this optimization if necessary. 1066168404Spjd */ 1067168404Spjd Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1068168404Spjd 1069168404Spjd /* Do not waste too much time if we already have a good match: */ 1070168404Spjd if (s->prev_length >= s->good_match) { 1071168404Spjd chain_length >>= 2; 1072168404Spjd } 1073168404Spjd /* Do not look for matches beyond the end of the input. This is necessary 1074168404Spjd * to make deflate deterministic. 1075168404Spjd */ 1076168404Spjd if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 1077168404Spjd 1078168404Spjd Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1079168404Spjd 1080168404Spjd do { 1081168404Spjd Assert(cur_match < s->strstart, "no future"); 1082168404Spjd match = s->window + cur_match; 1083168404Spjd 1084168404Spjd /* Skip to next match if the match length cannot increase 1085168404Spjd * or if the match length is less than 2. Note that the checks below 1086168404Spjd * for insufficient lookahead only occur occasionally for performance 1087168404Spjd * reasons. Therefore uninitialized memory will be accessed, and 1088168404Spjd * conditional jumps will be made that depend on those values. 1089168404Spjd * However the length of the match is limited to the lookahead, so 1090168404Spjd * the output of deflate is not affected by the uninitialized values. 1091168404Spjd */ 1092168404Spjd#if (defined(UNALIGNED_OK) && MAX_MATCH == 258) 1093168404Spjd /* This code assumes sizeof(unsigned short) == 2. Do not use 1094168404Spjd * UNALIGNED_OK if your compiler uses a different size. 1095168404Spjd */ 1096168404Spjd if (*(ushf*)(match+best_len-1) != scan_end || 1097168404Spjd *(ushf*)match != scan_start) continue; 1098168404Spjd 1099168404Spjd /* It is not necessary to compare scan[2] and match[2] since they are 1100168404Spjd * always equal when the other bytes match, given that the hash keys 1101168404Spjd * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at 1102168404Spjd * strstart+3, +5, ... up to strstart+257. We check for insufficient 1103168404Spjd * lookahead only every 4th comparison; the 128th check will be made 1104168404Spjd * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is 1105168404Spjd * necessary to put more guard bytes at the end of the window, or 1106168404Spjd * to check more often for insufficient lookahead. 1107168404Spjd */ 1108168404Spjd Assert(scan[2] == match[2], "scan[2]?"); 1109168404Spjd scan++, match++; 1110168404Spjd do { 1111168404Spjd } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1112168404Spjd *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1113168404Spjd *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1114168404Spjd *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 1115168404Spjd scan < strend); 1116168404Spjd /* The funny "do {}" generates better code on most compilers */ 1117168404Spjd 1118168404Spjd /* Here, scan <= window+strstart+257 */ 1119168404Spjd Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1120168404Spjd if (*scan == *match) scan++; 1121168404Spjd 1122168404Spjd len = (MAX_MATCH - 1) - (int)(strend-scan); 1123168404Spjd scan = strend - (MAX_MATCH-1); 1124168404Spjd 1125168404Spjd#else /* UNALIGNED_OK */ 1126168404Spjd 1127168404Spjd if (match[best_len] != scan_end || 1128168404Spjd match[best_len-1] != scan_end1 || 1129168404Spjd *match != *scan || 1130168404Spjd *++match != scan[1]) continue; 1131168404Spjd 1132168404Spjd /* The check at best_len-1 can be removed because it will be made 1133168404Spjd * again later. (This heuristic is not always a win.) 1134168404Spjd * It is not necessary to compare scan[2] and match[2] since they 1135168404Spjd * are always equal when the other bytes match, given that 1136168404Spjd * the hash keys are equal and that HASH_BITS >= 8. 1137168404Spjd */ 1138168404Spjd scan += 2, match++; 1139168404Spjd Assert(*scan == *match, "match[2]?"); 1140168404Spjd 1141168404Spjd /* We check for insufficient lookahead only every 8th comparison; 1142168404Spjd * the 256th check will be made at strstart+258. 1143168404Spjd */ 1144168404Spjd do { 1145168404Spjd } while (*++scan == *++match && *++scan == *++match && 1146168404Spjd *++scan == *++match && *++scan == *++match && 1147168404Spjd *++scan == *++match && *++scan == *++match && 1148168404Spjd *++scan == *++match && *++scan == *++match && 1149168404Spjd scan < strend); 1150168404Spjd 1151168404Spjd Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1152168404Spjd 1153168404Spjd len = MAX_MATCH - (int)(strend - scan); 1154168404Spjd scan = strend - MAX_MATCH; 1155168404Spjd 1156168404Spjd#endif /* UNALIGNED_OK */ 1157168404Spjd 1158168404Spjd if (len > best_len) { 1159168404Spjd s->match_start = cur_match; 1160168404Spjd best_len = len; 1161168404Spjd if (len >= nice_match) break; 1162168404Spjd#ifdef UNALIGNED_OK 1163168404Spjd scan_end = *(ushf*)(scan+best_len-1); 1164168404Spjd#else 1165168404Spjd scan_end1 = scan[best_len-1]; 1166168404Spjd scan_end = scan[best_len]; 1167168404Spjd#endif 1168168404Spjd } 1169168404Spjd } while ((cur_match = prev[cur_match & wmask]) > limit 1170168404Spjd && --chain_length != 0); 1171168404Spjd 1172168404Spjd if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 1173168404Spjd return s->lookahead; 1174168404Spjd} 1175168404Spjd#endif /* ASMV */ 1176168404Spjd#endif /* FASTEST */ 1177168404Spjd 1178168404Spjd/* --------------------------------------------------------------------------- 1179168404Spjd * Optimized version for level == 1 or strategy == Z_RLE only 1180168404Spjd */ 1181168404Spjdlocal uInt longest_match_fast(s, cur_match) 1182168404Spjd deflate_state *s; 1183168404Spjd IPos cur_match; /* current match */ 1184168404Spjd{ 1185168404Spjd register Bytef *scan = s->window + s->strstart; /* current string */ 1186168404Spjd register Bytef *match; /* matched string */ 1187168404Spjd register int len; /* length of current match */ 1188168404Spjd register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1189168404Spjd 1190168404Spjd /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1191168404Spjd * It is easy to get rid of this optimization if necessary. 1192168404Spjd */ 1193168404Spjd Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1194168404Spjd 1195168404Spjd Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1196168404Spjd 1197168404Spjd Assert(cur_match < s->strstart, "no future"); 1198168404Spjd 1199168404Spjd match = s->window + cur_match; 1200168404Spjd 1201168404Spjd /* Return failure if the match length is less than 2: 1202168404Spjd */ 1203168404Spjd if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; 1204168404Spjd 1205168404Spjd /* The check at best_len-1 can be removed because it will be made 1206168404Spjd * again later. (This heuristic is not always a win.) 1207168404Spjd * It is not necessary to compare scan[2] and match[2] since they 1208168404Spjd * are always equal when the other bytes match, given that 1209168404Spjd * the hash keys are equal and that HASH_BITS >= 8. 1210168404Spjd */ 1211168404Spjd scan += 2, match += 2; 1212168404Spjd Assert(*scan == *match, "match[2]?"); 1213168404Spjd 1214168404Spjd /* We check for insufficient lookahead only every 8th comparison; 1215168404Spjd * the 256th check will be made at strstart+258. 1216168404Spjd */ 1217168404Spjd do { 1218168404Spjd } while (*++scan == *++match && *++scan == *++match && 1219168404Spjd *++scan == *++match && *++scan == *++match && 1220168404Spjd *++scan == *++match && *++scan == *++match && 1221168404Spjd *++scan == *++match && *++scan == *++match && 1222168404Spjd scan < strend); 1223168404Spjd 1224168404Spjd Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1225168404Spjd 1226168404Spjd len = MAX_MATCH - (int)(strend - scan); 1227168404Spjd 1228168404Spjd if (len < MIN_MATCH) return MIN_MATCH - 1; 1229168404Spjd 1230168404Spjd s->match_start = cur_match; 1231168404Spjd return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; 1232168404Spjd} 1233168404Spjd 1234168404Spjd#ifdef DEBUG 1235168404Spjd/* =========================================================================== 1236168404Spjd * Check that the match at match_start is indeed a match. 1237168404Spjd */ 1238168404Spjdlocal void check_match(s, start, match, length) 1239168404Spjd deflate_state *s; 1240168404Spjd IPos start, match; 1241168404Spjd int length; 1242168404Spjd{ 1243168404Spjd /* check that the match is indeed a match */ 1244168404Spjd if (zmemcmp(s->window + match, 1245168404Spjd s->window + start, length) != EQUAL) { 1246168404Spjd fprintf(stderr, " start %u, match %u, length %d\n", 1247168404Spjd start, match, length); 1248168404Spjd do { 1249168404Spjd fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); 1250168404Spjd } while (--length != 0); 1251168404Spjd z_error("invalid match"); 1252168404Spjd } 1253168404Spjd if (z_verbose > 1) { 1254168404Spjd fprintf(stderr,"\\[%d,%d]", start-match, length); 1255168404Spjd do { putc(s->window[start++], stderr); } while (--length != 0); 1256168404Spjd } 1257168404Spjd} 1258168404Spjd#else 1259168404Spjd# define check_match(s, start, match, length) 1260168404Spjd#endif /* DEBUG */ 1261168404Spjd 1262168404Spjd/* =========================================================================== 1263168404Spjd * Fill the window when the lookahead becomes insufficient. 1264168404Spjd * Updates strstart and lookahead. 1265168404Spjd * 1266168404Spjd * IN assertion: lookahead < MIN_LOOKAHEAD 1267168404Spjd * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD 1268168404Spjd * At least one byte has been read, or avail_in == 0; reads are 1269168404Spjd * performed for at least two bytes (required for the zip translate_eol 1270168404Spjd * option -- not supported here). 1271168404Spjd */ 1272168404Spjdlocal void fill_window(s) 1273168404Spjd deflate_state *s; 1274168404Spjd{ 1275168404Spjd register unsigned n, m; 1276168404Spjd register Posf *p; 1277168404Spjd unsigned more; /* Amount of free space at the end of the window. */ 1278168404Spjd uInt wsize = s->w_size; 1279168404Spjd 1280168404Spjd do { 1281168404Spjd more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); 1282168404Spjd 1283168404Spjd /* Deal with !@#$% 64K limit: */ 1284168404Spjd if (sizeof(int) <= 2) { 1285168404Spjd if (more == 0 && s->strstart == 0 && s->lookahead == 0) { 1286168404Spjd more = wsize; 1287168404Spjd 1288168404Spjd } else if (more == (unsigned)(-1)) { 1289168404Spjd /* Very unlikely, but possible on 16 bit machine if 1290168404Spjd * strstart == 0 && lookahead == 1 (input done a byte at time) 1291168404Spjd */ 1292168404Spjd more--; 1293168404Spjd } 1294168404Spjd } 1295168404Spjd 1296168404Spjd /* If the window is almost full and there is insufficient lookahead, 1297168404Spjd * move the upper half to the lower one to make room in the upper half. 1298168404Spjd */ 1299168404Spjd if (s->strstart >= wsize+MAX_DIST(s)) { 1300168404Spjd 1301168404Spjd zmemcpy(s->window, s->window+wsize, (unsigned)wsize); 1302168404Spjd s->match_start -= wsize; 1303168404Spjd s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ 1304168404Spjd s->block_start -= (long) wsize; 1305168404Spjd 1306168404Spjd /* Slide the hash table (could be avoided with 32 bit values 1307168404Spjd at the expense of memory usage). We slide even when level == 0 1308168404Spjd to keep the hash table consistent if we switch back to level > 0 1309168404Spjd later. (Using level 0 permanently is not an optimal usage of 1310168404Spjd zlib, so we don't care about this pathological case.) 1311168404Spjd */ 1312168404Spjd /* %%% avoid this when Z_RLE */ 1313168404Spjd n = s->hash_size; 1314168404Spjd p = &s->head[n]; 1315168404Spjd do { 1316168404Spjd m = *--p; 1317168404Spjd *p = (Pos)(m >= wsize ? m-wsize : NIL); 1318168404Spjd } while (--n); 1319168404Spjd 1320168404Spjd n = wsize; 1321168404Spjd#ifndef FASTEST 1322168404Spjd p = &s->prev[n]; 1323168404Spjd do { 1324168404Spjd m = *--p; 1325168404Spjd *p = (Pos)(m >= wsize ? m-wsize : NIL); 1326168404Spjd /* If n is not on any hash chain, prev[n] is garbage but 1327168404Spjd * its value will never be used. 1328168404Spjd */ 1329168404Spjd } while (--n); 1330168404Spjd#endif 1331168404Spjd more += wsize; 1332168404Spjd } 1333168404Spjd if (s->strm->avail_in == 0) return; 1334168404Spjd 1335168404Spjd /* If there was no sliding: 1336168404Spjd * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && 1337168404Spjd * more == window_size - lookahead - strstart 1338168404Spjd * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) 1339168404Spjd * => more >= window_size - 2*WSIZE + 2 1340168404Spjd * In the BIG_MEM or MMAP case (not yet supported), 1341168404Spjd * window_size == input_size + MIN_LOOKAHEAD && 1342168404Spjd * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. 1343168404Spjd * Otherwise, window_size == 2*WSIZE so more >= 2. 1344168404Spjd * If there was sliding, more >= WSIZE. So in all cases, more >= 2. 1345168404Spjd */ 1346168404Spjd Assert(more >= 2, "more < 2"); 1347168404Spjd 1348168404Spjd n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); 1349168404Spjd s->lookahead += n; 1350168404Spjd 1351168404Spjd /* Initialize the hash value now that we have some input: */ 1352168404Spjd if (s->lookahead >= MIN_MATCH) { 1353168404Spjd s->ins_h = s->window[s->strstart]; 1354168404Spjd UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1355168404Spjd#if MIN_MATCH != 3 1356168404Spjd Call UPDATE_HASH() MIN_MATCH-3 more times 1357168404Spjd#endif 1358168404Spjd } 1359168404Spjd /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, 1360168404Spjd * but this is not important since only literal bytes will be emitted. 1361168404Spjd */ 1362168404Spjd 1363168404Spjd } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); 1364168404Spjd} 1365168404Spjd 1366168404Spjd/* =========================================================================== 1367168404Spjd * Flush the current block, with given end-of-file flag. 1368168404Spjd * IN assertion: strstart is set to the end of the current match. 1369168404Spjd */ 1370168404Spjd#define FLUSH_BLOCK_ONLY(s, eof) { \ 1371168404Spjd _tr_flush_block(s, (s->block_start >= 0L ? \ 1372168404Spjd (charf *)&s->window[(unsigned)s->block_start] : \ 1373168404Spjd (charf *)Z_NULL), \ 1374168404Spjd (ulg)((long)s->strstart - s->block_start), \ 1375168404Spjd (eof)); \ 1376168404Spjd s->block_start = s->strstart; \ 1377168404Spjd flush_pending(s->strm); \ 1378168404Spjd Tracev((stderr,"[FLUSH]")); \ 1379168404Spjd} 1380168404Spjd 1381168404Spjd/* Same but force premature exit if necessary. */ 1382168404Spjd#define FLUSH_BLOCK(s, eof) { \ 1383168404Spjd FLUSH_BLOCK_ONLY(s, eof); \ 1384168404Spjd if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ 1385168404Spjd} 1386168404Spjd 1387168404Spjd/* =========================================================================== 1388168404Spjd * Copy without compression as much as possible from the input stream, return 1389168404Spjd * the current block state. 1390168404Spjd * This function does not insert new strings in the dictionary since 1391168404Spjd * uncompressible data is probably not useful. This function is used 1392168404Spjd * only for the level=0 compression option. 1393168404Spjd * NOTE: this function should be optimized to avoid extra copying from 1394168404Spjd * window to pending_buf. 1395168404Spjd */ 1396168404Spjdlocal block_state deflate_stored(s, flush) 1397168404Spjd deflate_state *s; 1398168404Spjd int flush; 1399168404Spjd{ 1400168404Spjd /* Stored blocks are limited to 0xffff bytes, pending_buf is limited 1401168404Spjd * to pending_buf_size, and each stored block has a 5 byte header: 1402168404Spjd */ 1403168404Spjd ulg max_block_size = 0xffff; 1404168404Spjd ulg max_start; 1405168404Spjd 1406168404Spjd if (max_block_size > s->pending_buf_size - 5) { 1407168404Spjd max_block_size = s->pending_buf_size - 5; 1408168404Spjd } 1409168404Spjd 1410168404Spjd /* Copy as much as possible from input to output: */ 1411168404Spjd for (;;) { 1412168404Spjd /* Fill the window as much as possible: */ 1413168404Spjd if (s->lookahead <= 1) { 1414168404Spjd 1415168404Spjd Assert(s->strstart < s->w_size+MAX_DIST(s) || 1416168404Spjd s->block_start >= (long)s->w_size, "slide too late"); 1417168404Spjd 1418168404Spjd fill_window(s); 1419168404Spjd if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; 1420168404Spjd 1421168404Spjd if (s->lookahead == 0) break; /* flush the current block */ 1422168404Spjd } 1423168404Spjd Assert(s->block_start >= 0L, "block gone"); 1424168404Spjd 1425168404Spjd s->strstart += s->lookahead; 1426168404Spjd s->lookahead = 0; 1427168404Spjd 1428168404Spjd /* Emit a stored block if pending_buf will be full: */ 1429168404Spjd max_start = s->block_start + max_block_size; 1430168404Spjd if (s->strstart == 0 || (ulg)s->strstart >= max_start) { 1431168404Spjd /* strstart == 0 is possible when wraparound on 16-bit machine */ 1432168404Spjd s->lookahead = (uInt)(s->strstart - max_start); 1433168404Spjd s->strstart = (uInt)max_start; 1434168404Spjd FLUSH_BLOCK(s, 0); 1435168404Spjd } 1436168404Spjd /* Flush if we may have to slide, otherwise block_start may become 1437168404Spjd * negative and the data will be gone: 1438168404Spjd */ 1439168404Spjd if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { 1440168404Spjd FLUSH_BLOCK(s, 0); 1441168404Spjd } 1442168404Spjd } 1443168404Spjd FLUSH_BLOCK(s, flush == Z_FINISH); 1444168404Spjd return flush == Z_FINISH ? finish_done : block_done; 1445168404Spjd} 1446168404Spjd 1447168404Spjd/* =========================================================================== 1448168404Spjd * Compress as much as possible from the input stream, return the current 1449168404Spjd * block state. 1450168404Spjd * This function does not perform lazy evaluation of matches and inserts 1451168404Spjd * new strings in the dictionary only for unmatched strings or for short 1452168404Spjd * matches. It is used only for the fast compression options. 1453168404Spjd */ 1454168404Spjdlocal block_state deflate_fast(s, flush) 1455168404Spjd deflate_state *s; 1456168404Spjd int flush; 1457168404Spjd{ 1458168404Spjd IPos hash_head = NIL; /* head of the hash chain */ 1459168404Spjd int bflush; /* set if current block must be flushed */ 1460168404Spjd 1461168404Spjd for (;;) { 1462168404Spjd /* Make sure that we always have enough lookahead, except 1463168404Spjd * at the end of the input file. We need MAX_MATCH bytes 1464168404Spjd * for the next match, plus MIN_MATCH bytes to insert the 1465168404Spjd * string following the next match. 1466168404Spjd */ 1467168404Spjd if (s->lookahead < MIN_LOOKAHEAD) { 1468168404Spjd fill_window(s); 1469168404Spjd if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1470168404Spjd return need_more; 1471168404Spjd } 1472168404Spjd if (s->lookahead == 0) break; /* flush the current block */ 1473168404Spjd } 1474168404Spjd 1475168404Spjd /* Insert the string window[strstart .. strstart+2] in the 1476168404Spjd * dictionary, and set hash_head to the head of the hash chain: 1477168404Spjd */ 1478168404Spjd if (s->lookahead >= MIN_MATCH) { 1479168404Spjd INSERT_STRING(s, s->strstart, hash_head); 1480168404Spjd } 1481168404Spjd 1482168404Spjd /* Find the longest match, discarding those <= prev_length. 1483168404Spjd * At this point we have always match_length < MIN_MATCH 1484168404Spjd */ 1485168404Spjd if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { 1486168404Spjd /* To simplify the code, we prevent matches with the string 1487168404Spjd * of window index 0 (in particular we have to avoid a match 1488168404Spjd * of the string with itself at the start of the input file). 1489168404Spjd */ 1490168404Spjd#ifdef FASTEST 1491168404Spjd if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) || 1492168404Spjd (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { 1493168404Spjd s->match_length = longest_match_fast (s, hash_head); 1494168404Spjd } 1495168404Spjd#else 1496168404Spjd if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { 1497168404Spjd s->match_length = longest_match (s, hash_head); 1498168404Spjd } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1499168404Spjd s->match_length = longest_match_fast (s, hash_head); 1500168404Spjd } 1501168404Spjd#endif 1502168404Spjd /* longest_match() or longest_match_fast() sets match_start */ 1503168404Spjd } 1504168404Spjd if (s->match_length >= MIN_MATCH) { 1505168404Spjd check_match(s, s->strstart, s->match_start, s->match_length); 1506168404Spjd 1507168404Spjd _tr_tally_dist(s, s->strstart - s->match_start, 1508168404Spjd s->match_length - MIN_MATCH, bflush); 1509168404Spjd 1510168404Spjd s->lookahead -= s->match_length; 1511168404Spjd 1512168404Spjd /* Insert new strings in the hash table only if the match length 1513168404Spjd * is not too large. This saves time but degrades compression. 1514168404Spjd */ 1515168404Spjd#ifndef FASTEST 1516168404Spjd if (s->match_length <= s->max_insert_length && 1517168404Spjd s->lookahead >= MIN_MATCH) { 1518168404Spjd s->match_length--; /* string at strstart already in table */ 1519168404Spjd do { 1520168404Spjd s->strstart++; 1521168404Spjd INSERT_STRING(s, s->strstart, hash_head); 1522168404Spjd /* strstart never exceeds WSIZE-MAX_MATCH, so there are 1523168404Spjd * always MIN_MATCH bytes ahead. 1524168404Spjd */ 1525168404Spjd } while (--s->match_length != 0); 1526168404Spjd s->strstart++; 1527168404Spjd } else 1528168404Spjd#endif 1529168404Spjd { 1530168404Spjd s->strstart += s->match_length; 1531168404Spjd s->match_length = 0; 1532168404Spjd s->ins_h = s->window[s->strstart]; 1533168404Spjd UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1534168404Spjd#if MIN_MATCH != 3 1535168404Spjd Call UPDATE_HASH() MIN_MATCH-3 more times 1536168404Spjd#endif 1537168404Spjd /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not 1538168404Spjd * matter since it will be recomputed at next deflate call. 1539168404Spjd */ 1540168404Spjd } 1541168404Spjd } else { 1542168404Spjd /* No match, output a literal byte */ 1543168404Spjd Tracevv((stderr,"%c", s->window[s->strstart])); 1544168404Spjd _tr_tally_lit (s, s->window[s->strstart], bflush); 1545168404Spjd s->lookahead--; 1546168404Spjd s->strstart++; 1547168404Spjd } 1548168404Spjd if (bflush) FLUSH_BLOCK(s, 0); 1549168404Spjd } 1550168404Spjd FLUSH_BLOCK(s, flush == Z_FINISH); 1551168404Spjd return flush == Z_FINISH ? finish_done : block_done; 1552168404Spjd} 1553168404Spjd 1554168404Spjd#ifndef FASTEST 1555168404Spjd/* =========================================================================== 1556168404Spjd * Same as above, but achieves better compression. We use a lazy 1557168404Spjd * evaluation for matches: a match is finally adopted only if there is 1558168404Spjd * no better match at the next window position. 1559168404Spjd */ 1560168404Spjdlocal block_state deflate_slow(s, flush) 1561168404Spjd deflate_state *s; 1562168404Spjd int flush; 1563168404Spjd{ 1564168404Spjd IPos hash_head = NIL; /* head of hash chain */ 1565168404Spjd int bflush; /* set if current block must be flushed */ 1566168404Spjd 1567168404Spjd /* Process the input block. */ 1568168404Spjd for (;;) { 1569168404Spjd /* Make sure that we always have enough lookahead, except 1570168404Spjd * at the end of the input file. We need MAX_MATCH bytes 1571168404Spjd * for the next match, plus MIN_MATCH bytes to insert the 1572168404Spjd * string following the next match. 1573168404Spjd */ 1574168404Spjd if (s->lookahead < MIN_LOOKAHEAD) { 1575168404Spjd fill_window(s); 1576168404Spjd if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1577168404Spjd return need_more; 1578168404Spjd } 1579168404Spjd if (s->lookahead == 0) break; /* flush the current block */ 1580168404Spjd } 1581168404Spjd 1582168404Spjd /* Insert the string window[strstart .. strstart+2] in the 1583168404Spjd * dictionary, and set hash_head to the head of the hash chain: 1584168404Spjd */ 1585168404Spjd if (s->lookahead >= MIN_MATCH) { 1586168404Spjd INSERT_STRING(s, s->strstart, hash_head); 1587168404Spjd } 1588168404Spjd 1589168404Spjd /* Find the longest match, discarding those <= prev_length. 1590168404Spjd */ 1591168404Spjd s->prev_length = s->match_length, s->prev_match = s->match_start; 1592168404Spjd s->match_length = MIN_MATCH-1; 1593168404Spjd 1594168404Spjd if (hash_head != NIL && s->prev_length < s->max_lazy_match && 1595168404Spjd s->strstart - hash_head <= MAX_DIST(s)) { 1596168404Spjd /* To simplify the code, we prevent matches with the string 1597168404Spjd * of window index 0 (in particular we have to avoid a match 1598168404Spjd * of the string with itself at the start of the input file). 1599168404Spjd */ 1600168404Spjd if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { 1601168404Spjd s->match_length = longest_match (s, hash_head); 1602168404Spjd } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1603168404Spjd s->match_length = longest_match_fast (s, hash_head); 1604168404Spjd } 1605168404Spjd /* longest_match() or longest_match_fast() sets match_start */ 1606168404Spjd 1607168404Spjd if (s->match_length <= 5 && (s->strategy == Z_FILTERED 1608168404Spjd#if TOO_FAR <= 32767 1609168404Spjd || (s->match_length == MIN_MATCH && 1610168404Spjd s->strstart - s->match_start > TOO_FAR) 1611168404Spjd#endif 1612168404Spjd )) { 1613168404Spjd 1614168404Spjd /* If prev_match is also MIN_MATCH, match_start is garbage 1615168404Spjd * but we will ignore the current match anyway. 1616168404Spjd */ 1617168404Spjd s->match_length = MIN_MATCH-1; 1618168404Spjd } 1619168404Spjd } 1620168404Spjd /* If there was a match at the previous step and the current 1621168404Spjd * match is not better, output the previous match: 1622168404Spjd */ 1623168404Spjd if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { 1624168404Spjd uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; 1625168404Spjd /* Do not insert strings in hash table beyond this. */ 1626168404Spjd 1627168404Spjd check_match(s, s->strstart-1, s->prev_match, s->prev_length); 1628168404Spjd 1629168404Spjd _tr_tally_dist(s, s->strstart -1 - s->prev_match, 1630168404Spjd s->prev_length - MIN_MATCH, bflush); 1631168404Spjd 1632168404Spjd /* Insert in hash table all strings up to the end of the match. 1633168404Spjd * strstart-1 and strstart are already inserted. If there is not 1634168404Spjd * enough lookahead, the last two strings are not inserted in 1635168404Spjd * the hash table. 1636168404Spjd */ 1637168404Spjd s->lookahead -= s->prev_length-1; 1638168404Spjd s->prev_length -= 2; 1639168404Spjd do { 1640168404Spjd if (++s->strstart <= max_insert) { 1641168404Spjd INSERT_STRING(s, s->strstart, hash_head); 1642168404Spjd } 1643168404Spjd } while (--s->prev_length != 0); 1644168404Spjd s->match_available = 0; 1645168404Spjd s->match_length = MIN_MATCH-1; 1646168404Spjd s->strstart++; 1647168404Spjd 1648168404Spjd if (bflush) FLUSH_BLOCK(s, 0); 1649168404Spjd 1650168404Spjd } else if (s->match_available) { 1651168404Spjd /* If there was no match at the previous position, output a 1652168404Spjd * single literal. If there was a match but the current match 1653168404Spjd * is longer, truncate the previous match to a single literal. 1654168404Spjd */ 1655168404Spjd Tracevv((stderr,"%c", s->window[s->strstart-1])); 1656168404Spjd _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1657168404Spjd if (bflush) { 1658168404Spjd FLUSH_BLOCK_ONLY(s, 0); 1659168404Spjd } 1660168404Spjd s->strstart++; 1661168404Spjd s->lookahead--; 1662168404Spjd if (s->strm->avail_out == 0) return need_more; 1663168404Spjd } else { 1664168404Spjd /* There is no previous match to compare with, wait for 1665168404Spjd * the next step to decide. 1666168404Spjd */ 1667168404Spjd s->match_available = 1; 1668168404Spjd s->strstart++; 1669168404Spjd s->lookahead--; 1670168404Spjd } 1671168404Spjd } 1672168404Spjd Assert (flush != Z_NO_FLUSH, "no flush?"); 1673168404Spjd if (s->match_available) { 1674168404Spjd Tracevv((stderr,"%c", s->window[s->strstart-1])); 1675168404Spjd _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1676168404Spjd s->match_available = 0; 1677168404Spjd } 1678168404Spjd FLUSH_BLOCK(s, flush == Z_FINISH); 1679168404Spjd return flush == Z_FINISH ? finish_done : block_done; 1680168404Spjd} 1681168404Spjd#endif /* FASTEST */ 1682168404Spjd 1683168404Spjd#if 0 1684168404Spjd/* =========================================================================== 1685168404Spjd * For Z_RLE, simply look for runs of bytes, generate matches only of distance 1686168404Spjd * one. Do not maintain a hash table. (It will be regenerated if this run of 1687168404Spjd * deflate switches away from Z_RLE.) 1688168404Spjd */ 1689168404Spjdlocal block_state deflate_rle(s, flush) 1690168404Spjd deflate_state *s; 1691168404Spjd int flush; 1692168404Spjd{ 1693168404Spjd int bflush; /* set if current block must be flushed */ 1694168404Spjd uInt run; /* length of run */ 1695168404Spjd uInt max; /* maximum length of run */ 1696168404Spjd uInt prev; /* byte at distance one to match */ 1697168404Spjd Bytef *scan; /* scan for end of run */ 1698168404Spjd 1699168404Spjd for (;;) { 1700168404Spjd /* Make sure that we always have enough lookahead, except 1701168404Spjd * at the end of the input file. We need MAX_MATCH bytes 1702168404Spjd * for the longest encodable run. 1703168404Spjd */ 1704168404Spjd if (s->lookahead < MAX_MATCH) { 1705168404Spjd fill_window(s); 1706168404Spjd if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { 1707168404Spjd return need_more; 1708168404Spjd } 1709168404Spjd if (s->lookahead == 0) break; /* flush the current block */ 1710168404Spjd } 1711168404Spjd 1712168404Spjd /* See how many times the previous byte repeats */ 1713168404Spjd run = 0; 1714168404Spjd if (s->strstart > 0) { /* if there is a previous byte, that is */ 1715168404Spjd max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH; 1716168404Spjd scan = s->window + s->strstart - 1; 1717168404Spjd prev = *scan++; 1718168404Spjd do { 1719168404Spjd if (*scan++ != prev) 1720168404Spjd break; 1721168404Spjd } while (++run < max); 1722168404Spjd } 1723168404Spjd 1724168404Spjd /* Emit match if have run of MIN_MATCH or longer, else emit literal */ 1725168404Spjd if (run >= MIN_MATCH) { 1726168404Spjd check_match(s, s->strstart, s->strstart - 1, run); 1727168404Spjd _tr_tally_dist(s, 1, run - MIN_MATCH, bflush); 1728168404Spjd s->lookahead -= run; 1729168404Spjd s->strstart += run; 1730168404Spjd } else { 1731168404Spjd /* No match, output a literal byte */ 1732168404Spjd Tracevv((stderr,"%c", s->window[s->strstart])); 1733168404Spjd _tr_tally_lit (s, s->window[s->strstart], bflush); 1734168404Spjd s->lookahead--; 1735168404Spjd s->strstart++; 1736168404Spjd } 1737168404Spjd if (bflush) FLUSH_BLOCK(s, 0); 1738168404Spjd } 1739168404Spjd FLUSH_BLOCK(s, flush == Z_FINISH); 1740168404Spjd return flush == Z_FINISH ? finish_done : block_done; 1741168404Spjd} 1742168404Spjd#endif 1743