| 1 | /* deflate.c -- compress data using the deflation algorithm␊ |
| 2 | * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler␊ |
| 3 | * For conditions of distribution and use, see copyright notice in zlib.h␊ |
| 4 | */␊ |
| 5 | ␊ |
| 6 | /*␊ |
| 7 | * ALGORITHM␊ |
| 8 | *␊ |
| 9 | * The "deflation" process depends on being able to identify portions␊ |
| 10 | * of the input text which are identical to earlier input (within a␊ |
| 11 | * sliding window trailing behind the input currently being processed).␊ |
| 12 | *␊ |
| 13 | * The most straightforward technique turns out to be the fastest for␊ |
| 14 | * most input files: try all possible matches and select the longest.␊ |
| 15 | * The key feature of this algorithm is that insertions into the string␊ |
| 16 | * dictionary are very simple and thus fast, and deletions are avoided␊ |
| 17 | * completely. Insertions are performed at each input character, whereas␊ |
| 18 | * string matches are performed only when the previous match ends. So it␊ |
| 19 | * is preferable to spend more time in matches to allow very fast string␊ |
| 20 | * insertions and avoid deletions. The matching algorithm for small␊ |
| 21 | * strings is inspired from that of Rabin & Karp. A brute force approach␊ |
| 22 | * is used to find longer strings when a small match has been found.␊ |
| 23 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze␊ |
| 24 | * (by Leonid Broukhis).␊ |
| 25 | * A previous version of this file used a more sophisticated algorithm␊ |
| 26 | * (by Fiala and Greene) which is guaranteed to run in linear amortized␊ |
| 27 | * time, but has a larger average cost, uses more memory and is patented.␊ |
| 28 | * However the F&G algorithm may be faster for some highly redundant␊ |
| 29 | * files if the parameter max_chain_length (described below) is too large.␊ |
| 30 | *␊ |
| 31 | * ACKNOWLEDGEMENTS␊ |
| 32 | *␊ |
| 33 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and␊ |
| 34 | * I found it in 'freeze' written by Leonid Broukhis.␊ |
| 35 | * Thanks to many people for bug reports and testing.␊ |
| 36 | *␊ |
| 37 | * REFERENCES␊ |
| 38 | *␊ |
| 39 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".␊ |
| 40 | * Available in http://www.ietf.org/rfc/rfc1951.txt␊ |
| 41 | *␊ |
| 42 | * A description of the Rabin and Karp algorithm is given in the book␊ |
| 43 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.␊ |
| 44 | *␊ |
| 45 | * Fiala,E.R., and Greene,D.H.␊ |
| 46 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595␊ |
| 47 | *␊ |
| 48 | */␊ |
| 49 | ␊ |
| 50 | /* @(#) $Id$ */␊ |
| 51 | ␊ |
| 52 | #include "deflate.h"␊ |
| 53 | ␊ |
| 54 | const char deflate_copyright[] =␊ |
| 55 | " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";␊ |
| 56 | /*␊ |
| 57 | If you use the zlib library in a product, an acknowledgment is welcome␊ |
| 58 | in the documentation of your product. If for some reason you cannot␊ |
| 59 | include such an acknowledgment, I would appreciate that you keep this␊ |
| 60 | copyright string in the executable of your product.␊ |
| 61 | */␊ |
| 62 | ␊ |
| 63 | /* ===========================================================================␊ |
| 64 | * Function prototypes.␊ |
| 65 | */␊ |
| 66 | typedef enum {␊ |
| 67 | need_more, /* block not completed, need more input or more output */␊ |
| 68 | block_done, /* block flush performed */␊ |
| 69 | finish_started, /* finish started, need only more output at next deflate */␊ |
| 70 | finish_done /* finish done, accept no more input or output */␊ |
| 71 | } block_state;␊ |
| 72 | ␊ |
| 73 | typedef block_state (*compress_func) OF((deflate_state *s, int flush));␊ |
| 74 | /* Compression function. Returns the block state after the call. */␊ |
| 75 | ␊ |
| 76 | local void fill_window OF((deflate_state *s));␊ |
| 77 | local block_state deflate_stored OF((deflate_state *s, int flush));␊ |
| 78 | local block_state deflate_fast OF((deflate_state *s, int flush));␊ |
| 79 | #ifndef FASTEST␊ |
| 80 | local block_state deflate_slow OF((deflate_state *s, int flush));␊ |
| 81 | #endif␊ |
| 82 | local block_state deflate_rle OF((deflate_state *s, int flush));␊ |
| 83 | local block_state deflate_huff OF((deflate_state *s, int flush));␊ |
| 84 | local void lm_init OF((deflate_state *s));␊ |
| 85 | local void putShortMSB OF((deflate_state *s, uInt b));␊ |
| 86 | local void flush_pending OF((z_streamp strm));␊ |
| 87 | local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));␊ |
| 88 | #ifdef ASMV␊ |
| 89 | void match_init OF((void)); /* asm code initialization */␊ |
| 90 | uInt longest_match OF((deflate_state *s, IPos cur_match));␊ |
| 91 | #else␊ |
| 92 | local uInt longest_match OF((deflate_state *s, IPos cur_match));␊ |
| 93 | #endif␊ |
| 94 | ␊ |
| 95 | #ifdef DEBUG␊ |
| 96 | local void check_match OF((deflate_state *s, IPos start, IPos match,␊ |
| 97 | int length));␊ |
| 98 | #endif␊ |
| 99 | ␊ |
| 100 | /* ===========================================================================␊ |
| 101 | * Local data␊ |
| 102 | */␊ |
| 103 | ␊ |
| 104 | #define NIL 0␊ |
| 105 | /* Tail of hash chains */␊ |
| 106 | ␊ |
| 107 | #ifndef TOO_FAR␊ |
| 108 | # define TOO_FAR 4096␊ |
| 109 | #endif␊ |
| 110 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */␊ |
| 111 | ␊ |
| 112 | /* Values for max_lazy_match, good_match and max_chain_length, depending on␊ |
| 113 | * the desired pack level (0..9). The values given below have been tuned to␊ |
| 114 | * exclude worst case performance for pathological files. Better values may be␊ |
| 115 | * found for specific files.␊ |
| 116 | */␊ |
| 117 | typedef struct config_s {␊ |
| 118 | ush good_length; /* reduce lazy search above this match length */␊ |
| 119 | ush max_lazy; /* do not perform lazy search above this match length */␊ |
| 120 | ush nice_length; /* quit search above this match length */␊ |
| 121 | ush max_chain;␊ |
| 122 | compress_func func;␊ |
| 123 | } config;␊ |
| 124 | ␊ |
| 125 | #ifdef FASTEST␊ |
| 126 | local const config configuration_table[2] = {␊ |
| 127 | /* good lazy nice chain */␊ |
| 128 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */␊ |
| 129 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */␊ |
| 130 | #else␊ |
| 131 | local const config configuration_table[10] = {␊ |
| 132 | /* good lazy nice chain */␊ |
| 133 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */␊ |
| 134 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */␊ |
| 135 | /* 2 */ {4, 5, 16, 8, deflate_fast},␊ |
| 136 | /* 3 */ {4, 6, 32, 32, deflate_fast},␊ |
| 137 | ␊ |
| 138 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */␊ |
| 139 | /* 5 */ {8, 16, 32, 32, deflate_slow},␊ |
| 140 | /* 6 */ {8, 16, 128, 128, deflate_slow},␊ |
| 141 | /* 7 */ {8, 32, 128, 256, deflate_slow},␊ |
| 142 | /* 8 */ {32, 128, 258, 1024, deflate_slow},␊ |
| 143 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */␊ |
| 144 | #endif␊ |
| 145 | ␊ |
| 146 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4␊ |
| 147 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different␊ |
| 148 | * meaning.␊ |
| 149 | */␊ |
| 150 | ␊ |
| 151 | #define EQUAL 0␊ |
| 152 | /* result of memcmp for equal strings */␊ |
| 153 | ␊ |
| 154 | #ifndef NO_DUMMY_DECL␊ |
| 155 | struct static_tree_desc_s {int dummy;}; /* for buggy compilers */␊ |
| 156 | #endif␊ |
| 157 | ␊ |
| 158 | /* ===========================================================================␊ |
| 159 | * Update a hash value with the given input byte␊ |
| 160 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive␊ |
| 161 | * input characters, so that a running hash key can be computed from the␊ |
| 162 | * previous key instead of complete recalculation each time.␊ |
| 163 | */␊ |
| 164 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)␊ |
| 165 | ␊ |
| 166 | ␊ |
| 167 | /* ===========================================================================␊ |
| 168 | * Insert string str in the dictionary and set match_head to the previous head␊ |
| 169 | * of the hash chain (the most recent string with same hash key). Return␊ |
| 170 | * the previous length of the hash chain.␊ |
| 171 | * If this file is compiled with -DFASTEST, the compression level is forced␊ |
| 172 | * to 1, and no hash chains are maintained.␊ |
| 173 | * IN assertion: all calls to to INSERT_STRING are made with consecutive␊ |
| 174 | * input characters and the first MIN_MATCH bytes of str are valid␊ |
| 175 | * (except for the last MIN_MATCH-1 bytes of the input file).␊ |
| 176 | */␊ |
| 177 | #ifdef FASTEST␊ |
| 178 | #define INSERT_STRING(s, str, match_head) \␊ |
| 179 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \␊ |
| 180 | match_head = s->head[s->ins_h], \␊ |
| 181 | s->head[s->ins_h] = (Pos)(str))␊ |
| 182 | #else␊ |
| 183 | #define INSERT_STRING(s, str, match_head) \␊ |
| 184 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \␊ |
| 185 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \␊ |
| 186 | s->head[s->ins_h] = (Pos)(str))␊ |
| 187 | #endif␊ |
| 188 | ␊ |
| 189 | /* ===========================================================================␊ |
| 190 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems).␊ |
| 191 | * prev[] will be initialized on the fly.␊ |
| 192 | */␊ |
| 193 | #define CLEAR_HASH(s) \␊ |
| 194 | s->head[s->hash_size-1] = NIL; \␊ |
| 195 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));␊ |
| 196 | ␊ |
| 197 | /* ========================================================================= */␊ |
| 198 | int ZEXPORT deflateInit_(strm, level, version, stream_size)␊ |
| 199 | z_streamp strm;␊ |
| 200 | int level;␊ |
| 201 | const char *version;␊ |
| 202 | int stream_size;␊ |
| 203 | {␊ |
| 204 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,␊ |
| 205 | Z_DEFAULT_STRATEGY, version, stream_size);␊ |
| 206 | /* To do: ignore strm->next_in if we use it as window */␊ |
| 207 | }␊ |
| 208 | ␊ |
| 209 | /* ========================================================================= */␊ |
| 210 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,␊ |
| 211 | version, stream_size)␊ |
| 212 | z_streamp strm;␊ |
| 213 | int level;␊ |
| 214 | int method;␊ |
| 215 | int windowBits;␊ |
| 216 | int memLevel;␊ |
| 217 | int strategy;␊ |
| 218 | const char *version;␊ |
| 219 | int stream_size;␊ |
| 220 | {␊ |
| 221 | deflate_state *s;␊ |
| 222 | int wrap = 1;␊ |
| 223 | static const char my_version[] = ZLIB_VERSION;␊ |
| 224 | ␊ |
| 225 | ushf *overlay;␊ |
| 226 | /* We overlay pending_buf and d_buf+l_buf. This works since the average␊ |
| 227 | * output size for (length,distance) codes is <= 24 bits.␊ |
| 228 | */␊ |
| 229 | ␊ |
| 230 | if (version == Z_NULL || version[0] != my_version[0] ||␊ |
| 231 | stream_size != sizeof(z_stream)) {␊ |
| 232 | return Z_VERSION_ERROR;␊ |
| 233 | }␊ |
| 234 | if (strm == Z_NULL) return Z_STREAM_ERROR;␊ |
| 235 | ␊ |
| 236 | strm->msg = Z_NULL;␊ |
| 237 | if (strm->zalloc == (alloc_func)0) {␊ |
| 238 | strm->zalloc = zcalloc;␊ |
| 239 | strm->opaque = (voidpf)0;␊ |
| 240 | }␊ |
| 241 | if (strm->zfree == (free_func)0) strm->zfree = zcfree;␊ |
| 242 | ␊ |
| 243 | #ifdef FASTEST␊ |
| 244 | if (level != 0) level = 1;␊ |
| 245 | #else␊ |
| 246 | if (level == Z_DEFAULT_COMPRESSION) level = 6;␊ |
| 247 | #endif␊ |
| 248 | ␊ |
| 249 | if (windowBits < 0) { /* suppress zlib wrapper */␊ |
| 250 | wrap = 0;␊ |
| 251 | windowBits = -windowBits;␊ |
| 252 | }␊ |
| 253 | #ifdef GZIP␊ |
| 254 | else if (windowBits > 15) {␊ |
| 255 | wrap = 2; /* write gzip wrapper instead */␊ |
| 256 | windowBits -= 16;␊ |
| 257 | }␊ |
| 258 | #endif␊ |
| 259 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||␊ |
| 260 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||␊ |
| 261 | strategy < 0 || strategy > Z_FIXED) {␊ |
| 262 | return Z_STREAM_ERROR;␊ |
| 263 | }␊ |
| 264 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */␊ |
| 265 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));␊ |
| 266 | if (s == Z_NULL) return Z_MEM_ERROR;␊ |
| 267 | strm->state = (struct internal_state FAR *)s;␊ |
| 268 | s->strm = strm;␊ |
| 269 | ␊ |
| 270 | s->wrap = wrap;␊ |
| 271 | s->gzhead = Z_NULL;␊ |
| 272 | s->w_bits = windowBits;␊ |
| 273 | s->w_size = 1 << s->w_bits;␊ |
| 274 | s->w_mask = s->w_size - 1;␊ |
| 275 | ␊ |
| 276 | s->hash_bits = memLevel + 7;␊ |
| 277 | s->hash_size = 1 << s->hash_bits;␊ |
| 278 | s->hash_mask = s->hash_size - 1;␊ |
| 279 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);␊ |
| 280 | ␊ |
| 281 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));␊ |
| 282 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));␊ |
| 283 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));␊ |
| 284 | ␊ |
| 285 | s->high_water = 0; /* nothing written to s->window yet */␊ |
| 286 | ␊ |
| 287 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */␊ |
| 288 | ␊ |
| 289 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);␊ |
| 290 | s->pending_buf = (uchf *) overlay;␊ |
| 291 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);␊ |
| 292 | ␊ |
| 293 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||␊ |
| 294 | s->pending_buf == Z_NULL) {␊ |
| 295 | s->status = FINISH_STATE;␊ |
| 296 | strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);␊ |
| 297 | deflateEnd (strm);␊ |
| 298 | return Z_MEM_ERROR;␊ |
| 299 | }␊ |
| 300 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush);␊ |
| 301 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;␊ |
| 302 | ␊ |
| 303 | s->level = level;␊ |
| 304 | s->strategy = strategy;␊ |
| 305 | s->method = (Byte)method;␊ |
| 306 | ␊ |
| 307 | return deflateReset(strm);␊ |
| 308 | }␊ |
| 309 | ␊ |
| 310 | /* ========================================================================= */␊ |
| 311 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)␊ |
| 312 | z_streamp strm;␊ |
| 313 | const Bytef *dictionary;␊ |
| 314 | uInt dictLength;␊ |
| 315 | {␊ |
| 316 | deflate_state *s;␊ |
| 317 | uInt length = dictLength;␊ |
| 318 | uInt n;␊ |
| 319 | IPos hash_head = 0;␊ |
| 320 | ␊ |
| 321 | if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||␊ |
| 322 | strm->state->wrap == 2 ||␊ |
| 323 | (strm->state->wrap == 1 && strm->state->status != INIT_STATE))␊ |
| 324 | return Z_STREAM_ERROR;␊ |
| 325 | ␊ |
| 326 | s = strm->state;␊ |
| 327 | if (s->wrap)␊ |
| 328 | strm->adler = adler32(strm->adler, dictionary, dictLength);␊ |
| 329 | ␊ |
| 330 | if (length < MIN_MATCH) return Z_OK;␊ |
| 331 | if (length > s->w_size) {␊ |
| 332 | length = s->w_size;␊ |
| 333 | dictionary += dictLength - length; /* use the tail of the dictionary */␊ |
| 334 | }␊ |
| 335 | zmemcpy(s->window, dictionary, length);␊ |
| 336 | s->strstart = length;␊ |
| 337 | s->block_start = (long)length;␊ |
| 338 | ␊ |
| 339 | /* Insert all strings in the hash table (except for the last two bytes).␊ |
| 340 | * s->lookahead stays null, so s->ins_h will be recomputed at the next␊ |
| 341 | * call of fill_window.␊ |
| 342 | */␊ |
| 343 | s->ins_h = s->window[0];␊ |
| 344 | UPDATE_HASH(s, s->ins_h, s->window[1]);␊ |
| 345 | for (n = 0; n <= length - MIN_MATCH; n++) {␊ |
| 346 | INSERT_STRING(s, n, hash_head);␊ |
| 347 | }␊ |
| 348 | #if 0␊ |
| 349 | #if UNUSED␊ |
| 350 | if (hash_head) hash_head = 0; /* to make compiler happy */␊ |
| 351 | #else␊ |
| 352 | ␉(void)hash_head;␊ |
| 353 | #endif␊ |
| 354 | #endif␊ |
| 355 | return Z_OK;␊ |
| 356 | }␊ |
| 357 | ␊ |
| 358 | /* ========================================================================= */␊ |
| 359 | int ZEXPORT deflateReset (strm)␊ |
| 360 | z_streamp strm;␊ |
| 361 | {␊ |
| 362 | deflate_state *s;␊ |
| 363 | ␊ |
| 364 | if (strm == Z_NULL || strm->state == Z_NULL ||␊ |
| 365 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {␊ |
| 366 | return Z_STREAM_ERROR;␊ |
| 367 | }␊ |
| 368 | ␊ |
| 369 | strm->total_in = strm->total_out = 0;␊ |
| 370 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */␊ |
| 371 | strm->data_type = Z_UNKNOWN;␊ |
| 372 | ␊ |
| 373 | s = (deflate_state *)strm->state;␊ |
| 374 | s->pending = 0;␊ |
| 375 | s->pending_out = s->pending_buf;␊ |
| 376 | ␊ |
| 377 | if (s->wrap < 0) {␊ |
| 378 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */␊ |
| 379 | }␊ |
| 380 | s->status = s->wrap ? INIT_STATE : BUSY_STATE;␊ |
| 381 | strm->adler =␊ |
| 382 | #ifdef GZIP␊ |
| 383 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) :␊ |
| 384 | #endif␊ |
| 385 | adler32(0L, Z_NULL, 0);␊ |
| 386 | s->last_flush = Z_NO_FLUSH;␊ |
| 387 | ␊ |
| 388 | _tr_init(s);␊ |
| 389 | lm_init(s);␊ |
| 390 | ␊ |
| 391 | return Z_OK;␊ |
| 392 | }␊ |
| 393 | ␊ |
| 394 | /* ========================================================================= */␊ |
| 395 | int ZEXPORT deflateSetHeader (strm, head)␊ |
| 396 | z_streamp strm;␊ |
| 397 | gz_headerp head;␊ |
| 398 | {␊ |
| 399 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
| 400 | if (strm->state->wrap != 2) return Z_STREAM_ERROR;␊ |
| 401 | strm->state->gzhead = head;␊ |
| 402 | return Z_OK;␊ |
| 403 | }␊ |
| 404 | ␊ |
| 405 | /* ========================================================================= */␊ |
| 406 | int ZEXPORT deflatePrime (strm, bits, value)␊ |
| 407 | z_streamp strm;␊ |
| 408 | int bits;␊ |
| 409 | int value;␊ |
| 410 | {␊ |
| 411 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
| 412 | strm->state->bi_valid = bits;␊ |
| 413 | strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));␊ |
| 414 | return Z_OK;␊ |
| 415 | }␊ |
| 416 | ␊ |
| 417 | /* ========================================================================= */␊ |
| 418 | int ZEXPORT deflateParams(strm, level, strategy)␊ |
| 419 | z_streamp strm;␊ |
| 420 | int level;␊ |
| 421 | int strategy;␊ |
| 422 | {␊ |
| 423 | deflate_state *s;␊ |
| 424 | compress_func func;␊ |
| 425 | int err = Z_OK;␊ |
| 426 | ␊ |
| 427 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
| 428 | s = strm->state;␊ |
| 429 | ␊ |
| 430 | #ifdef FASTEST␊ |
| 431 | if (level != 0) level = 1;␊ |
| 432 | #else␊ |
| 433 | if (level == Z_DEFAULT_COMPRESSION) level = 6;␊ |
| 434 | #endif␊ |
| 435 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {␊ |
| 436 | return Z_STREAM_ERROR;␊ |
| 437 | }␊ |
| 438 | func = configuration_table[s->level].func;␊ |
| 439 | ␊ |
| 440 | if ((strategy != s->strategy || func != configuration_table[level].func) &&␊ |
| 441 | strm->total_in != 0) {␊ |
| 442 | /* Flush the last buffer: */␊ |
| 443 | err = deflate(strm, Z_BLOCK);␊ |
| 444 | }␊ |
| 445 | if (s->level != level) {␊ |
| 446 | s->level = level;␊ |
| 447 | s->max_lazy_match = configuration_table[level].max_lazy;␊ |
| 448 | s->good_match = configuration_table[level].good_length;␊ |
| 449 | s->nice_match = configuration_table[level].nice_length;␊ |
| 450 | s->max_chain_length = configuration_table[level].max_chain;␊ |
| 451 | }␊ |
| 452 | s->strategy = strategy;␊ |
| 453 | return err;␊ |
| 454 | }␊ |
| 455 | ␊ |
| 456 | /* ========================================================================= */␊ |
| 457 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)␊ |
| 458 | z_streamp strm;␊ |
| 459 | int good_length;␊ |
| 460 | int max_lazy;␊ |
| 461 | int nice_length;␊ |
| 462 | int max_chain;␊ |
| 463 | {␊ |
| 464 | deflate_state *s;␊ |
| 465 | ␊ |
| 466 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
| 467 | s = strm->state;␊ |
| 468 | s->good_match = good_length;␊ |
| 469 | s->max_lazy_match = max_lazy;␊ |
| 470 | s->nice_match = nice_length;␊ |
| 471 | s->max_chain_length = max_chain;␊ |
| 472 | return Z_OK;␊ |
| 473 | }␊ |
| 474 | ␊ |
| 475 | /* =========================================================================␊ |
| 476 | * For the default windowBits of 15 and memLevel of 8, this function returns␊ |
| 477 | * a close to exact, as well as small, upper bound on the compressed size.␊ |
| 478 | * They are coded as constants here for a reason--if the #define's are␊ |
| 479 | * changed, then this function needs to be changed as well. The return␊ |
| 480 | * value for 15 and 8 only works for those exact settings.␊ |
| 481 | *␊ |
| 482 | * For any setting other than those defaults for windowBits and memLevel,␊ |
| 483 | * the value returned is a conservative worst case for the maximum expansion␊ |
| 484 | * resulting from using fixed blocks instead of stored blocks, which deflate␊ |
| 485 | * can emit on compressed data for some combinations of the parameters.␊ |
| 486 | *␊ |
| 487 | * This function could be more sophisticated to provide closer upper bounds for␊ |
| 488 | * every combination of windowBits and memLevel. But even the conservative␊ |
| 489 | * upper bound of about 14% expansion does not seem onerous for output buffer␊ |
| 490 | * allocation.␊ |
| 491 | */␊ |
| 492 | uLong ZEXPORT deflateBound(strm, sourceLen)␊ |
| 493 | z_streamp strm;␊ |
| 494 | uLong sourceLen;␊ |
| 495 | {␊ |
| 496 | deflate_state *s;␊ |
| 497 | uLong complen, wraplen;␊ |
| 498 | Bytef *str;␊ |
| 499 | ␊ |
| 500 | /* conservative upper bound for compressed data */␊ |
| 501 | complen = sourceLen +␊ |
| 502 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;␊ |
| 503 | ␊ |
| 504 | /* if can't get parameters, return conservative bound plus zlib wrapper */␊ |
| 505 | if (strm == Z_NULL || strm->state == Z_NULL)␊ |
| 506 | return complen + 6;␊ |
| 507 | ␊ |
| 508 | /* compute wrapper length */␊ |
| 509 | s = strm->state;␊ |
| 510 | switch (s->wrap) {␊ |
| 511 | case 0: /* raw deflate */␊ |
| 512 | wraplen = 0;␊ |
| 513 | break;␊ |
| 514 | case 1: /* zlib wrapper */␊ |
| 515 | wraplen = 6 + (s->strstart ? 4 : 0);␊ |
| 516 | break;␊ |
| 517 | case 2: /* gzip wrapper */␊ |
| 518 | wraplen = 18;␊ |
| 519 | if (s->gzhead != Z_NULL) { /* user-supplied gzip header */␊ |
| 520 | if (s->gzhead->extra != Z_NULL)␊ |
| 521 | wraplen += 2 + s->gzhead->extra_len;␊ |
| 522 | str = s->gzhead->name;␊ |
| 523 | if (str != Z_NULL)␊ |
| 524 | do {␊ |
| 525 | wraplen++;␊ |
| 526 | } while (*str++);␊ |
| 527 | str = s->gzhead->comment;␊ |
| 528 | if (str != Z_NULL)␊ |
| 529 | do {␊ |
| 530 | wraplen++;␊ |
| 531 | } while (*str++);␊ |
| 532 | if (s->gzhead->hcrc)␊ |
| 533 | wraplen += 2;␊ |
| 534 | }␊ |
| 535 | break;␊ |
| 536 | default: /* for compiler happiness */␊ |
| 537 | wraplen = 6;␊ |
| 538 | }␊ |
| 539 | ␊ |
| 540 | /* if not default parameters, return conservative bound */␊ |
| 541 | if (s->w_bits != 15 || s->hash_bits != 8 + 7)␊ |
| 542 | return complen + wraplen;␊ |
| 543 | ␊ |
| 544 | /* default settings: return tight bound for that case */␊ |
| 545 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +␊ |
| 546 | (sourceLen >> 25) + 13 - 6 + wraplen;␊ |
| 547 | }␊ |
| 548 | ␊ |
| 549 | /* =========================================================================␊ |
| 550 | * Put a short in the pending buffer. The 16-bit value is put in MSB order.␊ |
| 551 | * IN assertion: the stream state is correct and there is enough room in␊ |
| 552 | * pending_buf.␊ |
| 553 | */␊ |
| 554 | local void putShortMSB (s, b)␊ |
| 555 | deflate_state *s;␊ |
| 556 | uInt b;␊ |
| 557 | {␊ |
| 558 | put_byte(s, (Byte)(b >> 8));␊ |
| 559 | put_byte(s, (Byte)(b & 0xff));␊ |
| 560 | }␊ |
| 561 | ␊ |
| 562 | /* =========================================================================␊ |
| 563 | * Flush as much pending output as possible. All deflate() output goes␊ |
| 564 | * through this function so some applications may wish to modify it␊ |
| 565 | * to avoid allocating a large strm->next_out buffer and copying into it.␊ |
| 566 | * (See also read_buf()).␊ |
| 567 | */␊ |
| 568 | local void flush_pending(strm)␊ |
| 569 | z_streamp strm;␊ |
| 570 | {␊ |
| 571 | unsigned len = strm->state->pending;␊ |
| 572 | ␊ |
| 573 | if (len > strm->avail_out) len = strm->avail_out;␊ |
| 574 | if (len == 0) return;␊ |
| 575 | ␊ |
| 576 | zmemcpy(strm->next_out, strm->state->pending_out, len);␊ |
| 577 | strm->next_out += len;␊ |
| 578 | strm->state->pending_out += len;␊ |
| 579 | strm->total_out += len;␊ |
| 580 | strm->avail_out -= len;␊ |
| 581 | strm->state->pending -= len;␊ |
| 582 | if (strm->state->pending == 0) {␊ |
| 583 | strm->state->pending_out = strm->state->pending_buf;␊ |
| 584 | }␊ |
| 585 | }␊ |
| 586 | ␊ |
| 587 | /* ========================================================================= */␊ |
| 588 | int ZEXPORT deflate (strm, flush)␊ |
| 589 | z_streamp strm;␊ |
| 590 | int flush;␊ |
| 591 | {␊ |
| 592 | int old_flush; /* value of flush param for previous deflate call */␊ |
| 593 | deflate_state *s;␊ |
| 594 | ␊ |
| 595 | if (strm == Z_NULL || strm->state == Z_NULL ||␊ |
| 596 | flush > Z_BLOCK || flush < 0) {␊ |
| 597 | return Z_STREAM_ERROR;␊ |
| 598 | }␊ |
| 599 | s = strm->state;␊ |
| 600 | ␊ |
| 601 | if (strm->next_out == Z_NULL ||␊ |
| 602 | (strm->next_in == Z_NULL && strm->avail_in != 0) ||␊ |
| 603 | (s->status == FINISH_STATE && flush != Z_FINISH)) {␊ |
| 604 | ERR_RETURN(strm, Z_STREAM_ERROR);␊ |
| 605 | }␊ |
| 606 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);␊ |
| 607 | ␊ |
| 608 | s->strm = strm; /* just in case */␊ |
| 609 | old_flush = s->last_flush;␊ |
| 610 | s->last_flush = flush;␊ |
| 611 | ␊ |
| 612 | /* Write the header */␊ |
| 613 | if (s->status == INIT_STATE) {␊ |
| 614 | #ifdef GZIP␊ |
| 615 | if (s->wrap == 2) {␊ |
| 616 | strm->adler = crc32(0L, Z_NULL, 0);␊ |
| 617 | put_byte(s, 31);␊ |
| 618 | put_byte(s, 139);␊ |
| 619 | put_byte(s, 8);␊ |
| 620 | if (s->gzhead == Z_NULL) {␊ |
| 621 | put_byte(s, 0);␊ |
| 622 | put_byte(s, 0);␊ |
| 623 | put_byte(s, 0);␊ |
| 624 | put_byte(s, 0);␊ |
| 625 | put_byte(s, 0);␊ |
| 626 | put_byte(s, s->level == 9 ? 2 :␊ |
| 627 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?␊ |
| 628 | 4 : 0));␊ |
| 629 | put_byte(s, OS_CODE);␊ |
| 630 | s->status = BUSY_STATE;␊ |
| 631 | }␊ |
| 632 | else {␊ |
| 633 | put_byte(s, (s->gzhead->text ? 1 : 0) +␊ |
| 634 | (s->gzhead->hcrc ? 2 : 0) +␊ |
| 635 | (s->gzhead->extra == Z_NULL ? 0 : 4) +␊ |
| 636 | (s->gzhead->name == Z_NULL ? 0 : 8) +␊ |
| 637 | (s->gzhead->comment == Z_NULL ? 0 : 16)␊ |
| 638 | );␊ |
| 639 | put_byte(s, (Byte)(s->gzhead->time & 0xff));␊ |
| 640 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));␊ |
| 641 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));␊ |
| 642 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));␊ |
| 643 | put_byte(s, s->level == 9 ? 2 :␊ |
| 644 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?␊ |
| 645 | 4 : 0));␊ |
| 646 | put_byte(s, s->gzhead->os & 0xff);␊ |
| 647 | if (s->gzhead->extra != Z_NULL) {␊ |
| 648 | put_byte(s, s->gzhead->extra_len & 0xff);␊ |
| 649 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);␊ |
| 650 | }␊ |
| 651 | if (s->gzhead->hcrc)␊ |
| 652 | strm->adler = crc32(strm->adler, s->pending_buf,␊ |
| 653 | s->pending);␊ |
| 654 | s->gzindex = 0;␊ |
| 655 | s->status = EXTRA_STATE;␊ |
| 656 | }␊ |
| 657 | }␊ |
| 658 | else␊ |
| 659 | #endif␊ |
| 660 | {␊ |
| 661 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;␊ |
| 662 | uInt level_flags;␊ |
| 663 | ␊ |
| 664 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)␊ |
| 665 | level_flags = 0;␊ |
| 666 | else if (s->level < 6)␊ |
| 667 | level_flags = 1;␊ |
| 668 | else if (s->level == 6)␊ |
| 669 | level_flags = 2;␊ |
| 670 | else␊ |
| 671 | level_flags = 3;␊ |
| 672 | header |= (level_flags << 6);␊ |
| 673 | if (s->strstart != 0) header |= PRESET_DICT;␊ |
| 674 | header += 31 - (header % 31);␊ |
| 675 | ␊ |
| 676 | s->status = BUSY_STATE;␊ |
| 677 | putShortMSB(s, header);␊ |
| 678 | ␊ |
| 679 | /* Save the adler32 of the preset dictionary: */␊ |
| 680 | if (s->strstart != 0) {␊ |
| 681 | putShortMSB(s, (uInt)(strm->adler >> 16));␊ |
| 682 | putShortMSB(s, (uInt)(strm->adler & 0xffff));␊ |
| 683 | }␊ |
| 684 | strm->adler = adler32(0L, Z_NULL, 0);␊ |
| 685 | }␊ |
| 686 | }␊ |
| 687 | #ifdef GZIP␊ |
| 688 | if (s->status == EXTRA_STATE) {␊ |
| 689 | if (s->gzhead->extra != Z_NULL) {␊ |
| 690 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
| 691 | ␊ |
| 692 | while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {␊ |
| 693 | if (s->pending == s->pending_buf_size) {␊ |
| 694 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 695 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 696 | s->pending - beg);␊ |
| 697 | flush_pending(strm);␊ |
| 698 | beg = s->pending;␊ |
| 699 | if (s->pending == s->pending_buf_size)␊ |
| 700 | break;␊ |
| 701 | }␊ |
| 702 | put_byte(s, s->gzhead->extra[s->gzindex]);␊ |
| 703 | s->gzindex++;␊ |
| 704 | }␊ |
| 705 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 706 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 707 | s->pending - beg);␊ |
| 708 | if (s->gzindex == s->gzhead->extra_len) {␊ |
| 709 | s->gzindex = 0;␊ |
| 710 | s->status = NAME_STATE;␊ |
| 711 | }␊ |
| 712 | }␊ |
| 713 | else␊ |
| 714 | s->status = NAME_STATE;␊ |
| 715 | }␊ |
| 716 | if (s->status == NAME_STATE) {␊ |
| 717 | if (s->gzhead->name != Z_NULL) {␊ |
| 718 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
| 719 | int val;␊ |
| 720 | ␊ |
| 721 | do {␊ |
| 722 | if (s->pending == s->pending_buf_size) {␊ |
| 723 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 724 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 725 | s->pending - beg);␊ |
| 726 | flush_pending(strm);␊ |
| 727 | beg = s->pending;␊ |
| 728 | if (s->pending == s->pending_buf_size) {␊ |
| 729 | val = 1;␊ |
| 730 | break;␊ |
| 731 | }␊ |
| 732 | }␊ |
| 733 | val = s->gzhead->name[s->gzindex++];␊ |
| 734 | put_byte(s, val);␊ |
| 735 | } while (val != 0);␊ |
| 736 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 737 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 738 | s->pending - beg);␊ |
| 739 | if (val == 0) {␊ |
| 740 | s->gzindex = 0;␊ |
| 741 | s->status = COMMENT_STATE;␊ |
| 742 | }␊ |
| 743 | }␊ |
| 744 | else␊ |
| 745 | s->status = COMMENT_STATE;␊ |
| 746 | }␊ |
| 747 | if (s->status == COMMENT_STATE) {␊ |
| 748 | if (s->gzhead->comment != Z_NULL) {␊ |
| 749 | uInt beg = s->pending; /* start of bytes to update crc */␊ |
| 750 | int val;␊ |
| 751 | ␊ |
| 752 | do {␊ |
| 753 | if (s->pending == s->pending_buf_size) {␊ |
| 754 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 755 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 756 | s->pending - beg);␊ |
| 757 | flush_pending(strm);␊ |
| 758 | beg = s->pending;␊ |
| 759 | if (s->pending == s->pending_buf_size) {␊ |
| 760 | val = 1;␊ |
| 761 | break;␊ |
| 762 | }␊ |
| 763 | }␊ |
| 764 | val = s->gzhead->comment[s->gzindex++];␊ |
| 765 | put_byte(s, val);␊ |
| 766 | } while (val != 0);␊ |
| 767 | if (s->gzhead->hcrc && s->pending > beg)␊ |
| 768 | strm->adler = crc32(strm->adler, s->pending_buf + beg,␊ |
| 769 | s->pending - beg);␊ |
| 770 | if (val == 0)␊ |
| 771 | s->status = HCRC_STATE;␊ |
| 772 | }␊ |
| 773 | else␊ |
| 774 | s->status = HCRC_STATE;␊ |
| 775 | }␊ |
| 776 | if (s->status == HCRC_STATE) {␊ |
| 777 | if (s->gzhead->hcrc) {␊ |
| 778 | if (s->pending + 2 > s->pending_buf_size)␊ |
| 779 | flush_pending(strm);␊ |
| 780 | if (s->pending + 2 <= s->pending_buf_size) {␊ |
| 781 | put_byte(s, (Byte)(strm->adler & 0xff));␊ |
| 782 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));␊ |
| 783 | strm->adler = crc32(0L, Z_NULL, 0);␊ |
| 784 | s->status = BUSY_STATE;␊ |
| 785 | }␊ |
| 786 | }␊ |
| 787 | else␊ |
| 788 | s->status = BUSY_STATE;␊ |
| 789 | }␊ |
| 790 | #endif␊ |
| 791 | ␊ |
| 792 | /* Flush as much pending output as possible */␊ |
| 793 | if (s->pending != 0) {␊ |
| 794 | flush_pending(strm);␊ |
| 795 | if (strm->avail_out == 0) {␊ |
| 796 | /* Since avail_out is 0, deflate will be called again with␊ |
| 797 | * more output space, but possibly with both pending and␊ |
| 798 | * avail_in equal to zero. There won't be anything to do,␊ |
| 799 | * but this is not an error situation so make sure we␊ |
| 800 | * return OK instead of BUF_ERROR at next call of deflate:␊ |
| 801 | */␊ |
| 802 | s->last_flush = -1;␊ |
| 803 | return Z_OK;␊ |
| 804 | }␊ |
| 805 | ␊ |
| 806 | /* Make sure there is something to do and avoid duplicate consecutive␊ |
| 807 | * flushes. For repeated and useless calls with Z_FINISH, we keep␊ |
| 808 | * returning Z_STREAM_END instead of Z_BUF_ERROR.␊ |
| 809 | */␊ |
| 810 | } else if (strm->avail_in == 0 && flush <= old_flush &&␊ |
| 811 | flush != Z_FINISH) {␊ |
| 812 | ERR_RETURN(strm, Z_BUF_ERROR);␊ |
| 813 | }␊ |
| 814 | ␊ |
| 815 | /* User must not provide more input after the first FINISH: */␊ |
| 816 | if (s->status == FINISH_STATE && strm->avail_in != 0) {␊ |
| 817 | ERR_RETURN(strm, Z_BUF_ERROR);␊ |
| 818 | }␊ |
| 819 | ␊ |
| 820 | /* Start a new block or continue the current one.␊ |
| 821 | */␊ |
| 822 | if (strm->avail_in != 0 || s->lookahead != 0 ||␊ |
| 823 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {␊ |
| 824 | block_state bstate;␊ |
| 825 | ␊ |
| 826 | bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :␊ |
| 827 | (s->strategy == Z_RLE ? deflate_rle(s, flush) :␊ |
| 828 | (*(configuration_table[s->level].func))(s, flush));␊ |
| 829 | ␊ |
| 830 | if (bstate == finish_started || bstate == finish_done) {␊ |
| 831 | s->status = FINISH_STATE;␊ |
| 832 | }␊ |
| 833 | if (bstate == need_more || bstate == finish_started) {␊ |
| 834 | if (strm->avail_out == 0) {␊ |
| 835 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */␊ |
| 836 | }␊ |
| 837 | return Z_OK;␊ |
| 838 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call␊ |
| 839 | * of deflate should use the same flush parameter to make sure␊ |
| 840 | * that the flush is complete. So we don't have to output an␊ |
| 841 | * empty block here, this will be done at next call. This also␊ |
| 842 | * ensures that for a very small output buffer, we emit at most␊ |
| 843 | * one empty block.␊ |
| 844 | */␊ |
| 845 | }␊ |
| 846 | if (bstate == block_done) {␊ |
| 847 | if (flush == Z_PARTIAL_FLUSH) {␊ |
| 848 | _tr_align(s);␊ |
| 849 | } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */␊ |
| 850 | _tr_stored_block(s, (char*)0, 0L, 0);␊ |
| 851 | /* For a full flush, this empty block will be recognized␊ |
| 852 | * as a special marker by inflate_sync().␊ |
| 853 | */␊ |
| 854 | if (flush == Z_FULL_FLUSH) {␊ |
| 855 | CLEAR_HASH(s); /* forget history */␊ |
| 856 | if (s->lookahead == 0) {␊ |
| 857 | s->strstart = 0;␊ |
| 858 | s->block_start = 0L;␊ |
| 859 | }␊ |
| 860 | }␊ |
| 861 | }␊ |
| 862 | flush_pending(strm);␊ |
| 863 | if (strm->avail_out == 0) {␊ |
| 864 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */␊ |
| 865 | return Z_OK;␊ |
| 866 | }␊ |
| 867 | }␊ |
| 868 | }␊ |
| 869 | Assert(strm->avail_out > 0, "bug2");␊ |
| 870 | ␊ |
| 871 | if (flush != Z_FINISH) return Z_OK;␊ |
| 872 | if (s->wrap <= 0) return Z_STREAM_END;␊ |
| 873 | ␊ |
| 874 | /* Write the trailer */␊ |
| 875 | #ifdef GZIP␊ |
| 876 | if (s->wrap == 2) {␊ |
| 877 | put_byte(s, (Byte)(strm->adler & 0xff));␊ |
| 878 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));␊ |
| 879 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff));␊ |
| 880 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff));␊ |
| 881 | put_byte(s, (Byte)(strm->total_in & 0xff));␊ |
| 882 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));␊ |
| 883 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));␊ |
| 884 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));␊ |
| 885 | }␊ |
| 886 | else␊ |
| 887 | #endif␊ |
| 888 | {␊ |
| 889 | putShortMSB(s, (uInt)(strm->adler >> 16));␊ |
| 890 | putShortMSB(s, (uInt)(strm->adler & 0xffff));␊ |
| 891 | }␊ |
| 892 | flush_pending(strm);␊ |
| 893 | /* If avail_out is zero, the application will call deflate again␊ |
| 894 | * to flush the rest.␊ |
| 895 | */␊ |
| 896 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */␊ |
| 897 | return s->pending != 0 ? Z_OK : Z_STREAM_END;␊ |
| 898 | }␊ |
| 899 | ␊ |
| 900 | /* ========================================================================= */␊ |
| 901 | int ZEXPORT deflateEnd (strm)␊ |
| 902 | z_streamp strm;␊ |
| 903 | {␊ |
| 904 | int status;␊ |
| 905 | ␊ |
| 906 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;␊ |
| 907 | ␊ |
| 908 | status = strm->state->status;␊ |
| 909 | if (status != INIT_STATE &&␊ |
| 910 | status != EXTRA_STATE &&␊ |
| 911 | status != NAME_STATE &&␊ |
| 912 | status != COMMENT_STATE &&␊ |
| 913 | status != HCRC_STATE &&␊ |
| 914 | status != BUSY_STATE &&␊ |
| 915 | status != FINISH_STATE) {␊ |
| 916 | return Z_STREAM_ERROR;␊ |
| 917 | }␊ |
| 918 | ␊ |
| 919 | /* Deallocate in reverse order of allocations: */␊ |
| 920 | TRY_FREE(strm, strm->state->pending_buf);␊ |
| 921 | TRY_FREE(strm, strm->state->head);␊ |
| 922 | TRY_FREE(strm, strm->state->prev);␊ |
| 923 | TRY_FREE(strm, strm->state->window);␊ |
| 924 | ␊ |
| 925 | ZFREE(strm, strm->state);␊ |
| 926 | strm->state = Z_NULL;␊ |
| 927 | ␊ |
| 928 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;␊ |
| 929 | }␊ |
| 930 | ␊ |
| 931 | /* =========================================================================␊ |
| 932 | * Copy the source state to the destination state.␊ |
| 933 | * To simplify the source, this is not supported for 16-bit MSDOS (which␊ |
| 934 | * doesn't have enough memory anyway to duplicate compression states).␊ |
| 935 | */␊ |
| 936 | int ZEXPORT deflateCopy (dest, source)␊ |
| 937 | z_streamp dest;␊ |
| 938 | z_streamp source;␊ |
| 939 | {␊ |
| 940 | #ifdef MAXSEG_64K␊ |
| 941 | return Z_STREAM_ERROR;␊ |
| 942 | #else␊ |
| 943 | deflate_state *ds;␊ |
| 944 | deflate_state *ss;␊ |
| 945 | ushf *overlay;␊ |
| 946 | ␊ |
| 947 | ␊ |
| 948 | if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {␊ |
| 949 | return Z_STREAM_ERROR;␊ |
| 950 | }␊ |
| 951 | ␊ |
| 952 | ss = source->state;␊ |
| 953 | ␊ |
| 954 | zmemcpy(dest, source, sizeof(z_stream));␊ |
| 955 | ␊ |
| 956 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));␊ |
| 957 | if (ds == Z_NULL) return Z_MEM_ERROR;␊ |
| 958 | dest->state = (struct internal_state FAR *) ds;␊ |
| 959 | zmemcpy(ds, ss, sizeof(deflate_state));␊ |
| 960 | ds->strm = dest;␊ |
| 961 | ␊ |
| 962 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));␊ |
| 963 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));␊ |
| 964 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));␊ |
| 965 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);␊ |
| 966 | ds->pending_buf = (uchf *) overlay;␊ |
| 967 | ␊ |
| 968 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||␊ |
| 969 | ds->pending_buf == Z_NULL) {␊ |
| 970 | deflateEnd (dest);␊ |
| 971 | return Z_MEM_ERROR;␊ |
| 972 | }␊ |
| 973 | /* following zmemcpy do not work for 16-bit MSDOS */␊ |
| 974 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));␊ |
| 975 | zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));␊ |
| 976 | zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));␊ |
| 977 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);␊ |
| 978 | ␊ |
| 979 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);␊ |
| 980 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);␊ |
| 981 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;␊ |
| 982 | ␊ |
| 983 | ds->l_desc.dyn_tree = ds->dyn_ltree;␊ |
| 984 | ds->d_desc.dyn_tree = ds->dyn_dtree;␊ |
| 985 | ds->bl_desc.dyn_tree = ds->bl_tree;␊ |
| 986 | ␊ |
| 987 | return Z_OK;␊ |
| 988 | #endif /* MAXSEG_64K */␊ |
| 989 | }␊ |
| 990 | ␊ |
| 991 | /* ===========================================================================␊ |
| 992 | * Read a new buffer from the current input stream, update the adler32␊ |
| 993 | * and total number of bytes read. All deflate() input goes through␊ |
| 994 | * this function so some applications may wish to modify it to avoid␊ |
| 995 | * allocating a large strm->next_in buffer and copying from it.␊ |
| 996 | * (See also flush_pending()).␊ |
| 997 | */␊ |
| 998 | local int read_buf(strm, buf, size)␊ |
| 999 | z_streamp strm;␊ |
| 1000 | Bytef *buf;␊ |
| 1001 | unsigned size;␊ |
| 1002 | {␊ |
| 1003 | unsigned len = strm->avail_in;␊ |
| 1004 | ␊ |
| 1005 | if (len > size) len = size;␊ |
| 1006 | if (len == 0) return 0;␊ |
| 1007 | ␊ |
| 1008 | strm->avail_in -= len;␊ |
| 1009 | ␊ |
| 1010 | if (strm->state->wrap == 1) {␊ |
| 1011 | strm->adler = adler32(strm->adler, strm->next_in, len);␊ |
| 1012 | }␊ |
| 1013 | #ifdef GZIP␊ |
| 1014 | else if (strm->state->wrap == 2) {␊ |
| 1015 | strm->adler = crc32(strm->adler, strm->next_in, len);␊ |
| 1016 | }␊ |
| 1017 | #endif␊ |
| 1018 | zmemcpy(buf, strm->next_in, len);␊ |
| 1019 | strm->next_in += len;␊ |
| 1020 | strm->total_in += len;␊ |
| 1021 | ␊ |
| 1022 | return (int)len;␊ |
| 1023 | }␊ |
| 1024 | ␊ |
| 1025 | /* ===========================================================================␊ |
| 1026 | * Initialize the "longest match" routines for a new zlib stream␊ |
| 1027 | */␊ |
| 1028 | local void lm_init (s)␊ |
| 1029 | deflate_state *s;␊ |
| 1030 | {␊ |
| 1031 | s->window_size = (ulg)2L*s->w_size;␊ |
| 1032 | ␊ |
| 1033 | CLEAR_HASH(s);␊ |
| 1034 | ␊ |
| 1035 | /* Set the default configuration parameters:␊ |
| 1036 | */␊ |
| 1037 | s->max_lazy_match = configuration_table[s->level].max_lazy;␊ |
| 1038 | s->good_match = configuration_table[s->level].good_length;␊ |
| 1039 | s->nice_match = configuration_table[s->level].nice_length;␊ |
| 1040 | s->max_chain_length = configuration_table[s->level].max_chain;␊ |
| 1041 | ␊ |
| 1042 | s->strstart = 0;␊ |
| 1043 | s->block_start = 0L;␊ |
| 1044 | s->lookahead = 0;␊ |
| 1045 | s->match_length = s->prev_length = MIN_MATCH-1;␊ |
| 1046 | s->match_available = 0;␊ |
| 1047 | s->ins_h = 0;␊ |
| 1048 | #ifndef FASTEST␊ |
| 1049 | #ifdef ASMV␊ |
| 1050 | match_init(); /* initialize the asm code */␊ |
| 1051 | #endif␊ |
| 1052 | #endif␊ |
| 1053 | }␊ |
| 1054 | ␊ |
| 1055 | #ifndef FASTEST␊ |
| 1056 | /* ===========================================================================␊ |
| 1057 | * Set match_start to the longest match starting at the given string and␊ |
| 1058 | * return its length. Matches shorter or equal to prev_length are discarded,␊ |
| 1059 | * in which case the result is equal to prev_length and match_start is␊ |
| 1060 | * garbage.␊ |
| 1061 | * IN assertions: cur_match is the head of the hash chain for the current␊ |
| 1062 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1␊ |
| 1063 | * OUT assertion: the match length is not greater than s->lookahead.␊ |
| 1064 | */␊ |
| 1065 | #ifndef ASMV␊ |
| 1066 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or␊ |
| 1067 | * match.S. The code will be functionally equivalent.␊ |
| 1068 | */␊ |
| 1069 | local uInt longest_match(s, cur_match)␊ |
| 1070 | deflate_state *s;␊ |
| 1071 | IPos cur_match; /* current match */␊ |
| 1072 | {␊ |
| 1073 | unsigned chain_length = s->max_chain_length;/* max hash chain length */␊ |
| 1074 | register Bytef *scan = s->window + s->strstart; /* current string */␊ |
| 1075 | register Bytef *match; /* matched string */␊ |
| 1076 | register int len; /* length of current match */␊ |
| 1077 | int best_len = s->prev_length; /* best match length so far */␊ |
| 1078 | int nice_match = s->nice_match; /* stop if match long enough */␊ |
| 1079 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ?␊ |
| 1080 | s->strstart - (IPos)MAX_DIST(s) : NIL;␊ |
| 1081 | /* Stop when cur_match becomes <= limit. To simplify the code,␊ |
| 1082 | * we prevent matches with the string of window index 0.␊ |
| 1083 | */␊ |
| 1084 | Posf *prev = s->prev;␊ |
| 1085 | uInt wmask = s->w_mask;␊ |
| 1086 | ␊ |
| 1087 | #ifdef UNALIGNED_OK␊ |
| 1088 | /* Compare two bytes at a time. Note: this is not always beneficial.␊ |
| 1089 | * Try with and without -DUNALIGNED_OK to check.␊ |
| 1090 | */␊ |
| 1091 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;␊ |
| 1092 | register ush scan_start = *(ushf*)scan;␊ |
| 1093 | register ush scan_end = *(ushf*)(scan+best_len-1);␊ |
| 1094 | #else␊ |
| 1095 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;␊ |
| 1096 | register Byte scan_end1 = scan[best_len-1];␊ |
| 1097 | register Byte scan_end = scan[best_len];␊ |
| 1098 | #endif␊ |
| 1099 | ␊ |
| 1100 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.␊ |
| 1101 | * It is easy to get rid of this optimization if necessary.␊ |
| 1102 | */␊ |
| 1103 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");␊ |
| 1104 | ␊ |
| 1105 | /* Do not waste too much time if we already have a good match: */␊ |
| 1106 | if (s->prev_length >= s->good_match) {␊ |
| 1107 | chain_length >>= 2;␊ |
| 1108 | }␊ |
| 1109 | /* Do not look for matches beyond the end of the input. This is necessary␊ |
| 1110 | * to make deflate deterministic.␊ |
| 1111 | */␊ |
| 1112 | if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;␊ |
| 1113 | ␊ |
| 1114 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");␊ |
| 1115 | ␊ |
| 1116 | do {␊ |
| 1117 | Assert(cur_match < s->strstart, "no future");␊ |
| 1118 | match = s->window + cur_match;␊ |
| 1119 | ␊ |
| 1120 | /* Skip to next match if the match length cannot increase␊ |
| 1121 | * or if the match length is less than 2. Note that the checks below␊ |
| 1122 | * for insufficient lookahead only occur occasionally for performance␊ |
| 1123 | * reasons. Therefore uninitialized memory will be accessed, and␊ |
| 1124 | * conditional jumps will be made that depend on those values.␊ |
| 1125 | * However the length of the match is limited to the lookahead, so␊ |
| 1126 | * the output of deflate is not affected by the uninitialized values.␊ |
| 1127 | */␊ |
| 1128 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)␊ |
| 1129 | /* This code assumes sizeof(unsigned short) == 2. Do not use␊ |
| 1130 | * UNALIGNED_OK if your compiler uses a different size.␊ |
| 1131 | */␊ |
| 1132 | if (*(ushf*)(match+best_len-1) != scan_end ||␊ |
| 1133 | *(ushf*)match != scan_start) continue;␊ |
| 1134 | ␊ |
| 1135 | /* It is not necessary to compare scan[2] and match[2] since they are␊ |
| 1136 | * always equal when the other bytes match, given that the hash keys␊ |
| 1137 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at␊ |
| 1138 | * strstart+3, +5, ... up to strstart+257. We check for insufficient␊ |
| 1139 | * lookahead only every 4th comparison; the 128th check will be made␊ |
| 1140 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is␊ |
| 1141 | * necessary to put more guard bytes at the end of the window, or␊ |
| 1142 | * to check more often for insufficient lookahead.␊ |
| 1143 | */␊ |
| 1144 | Assert(scan[2] == match[2], "scan[2]?");␊ |
| 1145 | scan++, match++;␊ |
| 1146 | do {␊ |
| 1147 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
| 1148 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
| 1149 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
| 1150 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&␊ |
| 1151 | scan < strend);␊ |
| 1152 | /* The funny "do {}" generates better code on most compilers */␊ |
| 1153 | ␊ |
| 1154 | /* Here, scan <= window+strstart+257 */␊ |
| 1155 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
| 1156 | if (*scan == *match) scan++;␊ |
| 1157 | ␊ |
| 1158 | len = (MAX_MATCH - 1) - (int)(strend-scan);␊ |
| 1159 | scan = strend - (MAX_MATCH-1);␊ |
| 1160 | ␊ |
| 1161 | #else /* UNALIGNED_OK */␊ |
| 1162 | ␊ |
| 1163 | if (match[best_len] != scan_end ||␊ |
| 1164 | match[best_len-1] != scan_end1 ||␊ |
| 1165 | *match != *scan ||␊ |
| 1166 | *++match != scan[1]) continue;␊ |
| 1167 | ␊ |
| 1168 | /* The check at best_len-1 can be removed because it will be made␊ |
| 1169 | * again later. (This heuristic is not always a win.)␊ |
| 1170 | * It is not necessary to compare scan[2] and match[2] since they␊ |
| 1171 | * are always equal when the other bytes match, given that␊ |
| 1172 | * the hash keys are equal and that HASH_BITS >= 8.␊ |
| 1173 | */␊ |
| 1174 | scan += 2, match++;␊ |
| 1175 | Assert(*scan == *match, "match[2]?");␊ |
| 1176 | ␊ |
| 1177 | /* We check for insufficient lookahead only every 8th comparison;␊ |
| 1178 | * the 256th check will be made at strstart+258.␊ |
| 1179 | */␊ |
| 1180 | do {␊ |
| 1181 | } while (*++scan == *++match && *++scan == *++match &&␊ |
| 1182 | *++scan == *++match && *++scan == *++match &&␊ |
| 1183 | *++scan == *++match && *++scan == *++match &&␊ |
| 1184 | *++scan == *++match && *++scan == *++match &&␊ |
| 1185 | scan < strend);␊ |
| 1186 | ␊ |
| 1187 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
| 1188 | ␊ |
| 1189 | len = MAX_MATCH - (int)(strend - scan);␊ |
| 1190 | scan = strend - MAX_MATCH;␊ |
| 1191 | ␊ |
| 1192 | #endif /* UNALIGNED_OK */␊ |
| 1193 | ␊ |
| 1194 | if (len > best_len) {␊ |
| 1195 | s->match_start = cur_match;␊ |
| 1196 | best_len = len;␊ |
| 1197 | if (len >= nice_match) break;␊ |
| 1198 | #ifdef UNALIGNED_OK␊ |
| 1199 | scan_end = *(ushf*)(scan+best_len-1);␊ |
| 1200 | #else␊ |
| 1201 | scan_end1 = scan[best_len-1];␊ |
| 1202 | scan_end = scan[best_len];␊ |
| 1203 | #endif␊ |
| 1204 | }␊ |
| 1205 | } while ((cur_match = prev[cur_match & wmask]) > limit␊ |
| 1206 | && --chain_length != 0);␊ |
| 1207 | ␊ |
| 1208 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len;␊ |
| 1209 | return s->lookahead;␊ |
| 1210 | }␊ |
| 1211 | #endif /* ASMV */␊ |
| 1212 | ␊ |
| 1213 | #else /* FASTEST */␊ |
| 1214 | ␊ |
| 1215 | /* ---------------------------------------------------------------------------␊ |
| 1216 | * Optimized version for FASTEST only␊ |
| 1217 | */␊ |
| 1218 | local uInt longest_match(s, cur_match)␊ |
| 1219 | deflate_state *s;␊ |
| 1220 | IPos cur_match; /* current match */␊ |
| 1221 | {␊ |
| 1222 | register Bytef *scan = s->window + s->strstart; /* current string */␊ |
| 1223 | register Bytef *match; /* matched string */␊ |
| 1224 | register int len; /* length of current match */␊ |
| 1225 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;␊ |
| 1226 | ␊ |
| 1227 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.␊ |
| 1228 | * It is easy to get rid of this optimization if necessary.␊ |
| 1229 | */␊ |
| 1230 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");␊ |
| 1231 | ␊ |
| 1232 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");␊ |
| 1233 | ␊ |
| 1234 | Assert(cur_match < s->strstart, "no future");␊ |
| 1235 | ␊ |
| 1236 | match = s->window + cur_match;␊ |
| 1237 | ␊ |
| 1238 | /* Return failure if the match length is less than 2:␊ |
| 1239 | */␊ |
| 1240 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;␊ |
| 1241 | ␊ |
| 1242 | /* The check at best_len-1 can be removed because it will be made␊ |
| 1243 | * again later. (This heuristic is not always a win.)␊ |
| 1244 | * It is not necessary to compare scan[2] and match[2] since they␊ |
| 1245 | * are always equal when the other bytes match, given that␊ |
| 1246 | * the hash keys are equal and that HASH_BITS >= 8.␊ |
| 1247 | */␊ |
| 1248 | scan += 2, match += 2;␊ |
| 1249 | Assert(*scan == *match, "match[2]?");␊ |
| 1250 | ␊ |
| 1251 | /* We check for insufficient lookahead only every 8th comparison;␊ |
| 1252 | * the 256th check will be made at strstart+258.␊ |
| 1253 | */␊ |
| 1254 | do {␊ |
| 1255 | } while (*++scan == *++match && *++scan == *++match &&␊ |
| 1256 | *++scan == *++match && *++scan == *++match &&␊ |
| 1257 | *++scan == *++match && *++scan == *++match &&␊ |
| 1258 | *++scan == *++match && *++scan == *++match &&␊ |
| 1259 | scan < strend);␊ |
| 1260 | ␊ |
| 1261 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");␊ |
| 1262 | ␊ |
| 1263 | len = MAX_MATCH - (int)(strend - scan);␊ |
| 1264 | ␊ |
| 1265 | if (len < MIN_MATCH) return MIN_MATCH - 1;␊ |
| 1266 | ␊ |
| 1267 | s->match_start = cur_match;␊ |
| 1268 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;␊ |
| 1269 | }␊ |
| 1270 | ␊ |
| 1271 | #endif /* FASTEST */␊ |
| 1272 | ␊ |
| 1273 | #ifdef DEBUG␊ |
| 1274 | /* ===========================================================================␊ |
| 1275 | * Check that the match at match_start is indeed a match.␊ |
| 1276 | */␊ |
| 1277 | local void check_match(s, start, match, length)␊ |
| 1278 | deflate_state *s;␊ |
| 1279 | IPos start, match;␊ |
| 1280 | int length;␊ |
| 1281 | {␊ |
| 1282 | /* check that the match is indeed a match */␊ |
| 1283 | if (zmemcmp(s->window + match,␊ |
| 1284 | s->window + start, length) != EQUAL) {␊ |
| 1285 | fprintf(stderr, " start %u, match %u, length %d\n",␊ |
| 1286 | start, match, length);␊ |
| 1287 | do {␊ |
| 1288 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);␊ |
| 1289 | } while (--length != 0);␊ |
| 1290 | z_error("invalid match");␊ |
| 1291 | }␊ |
| 1292 | if (z_verbose > 1) {␊ |
| 1293 | fprintf(stderr,"\\[%d,%d]", start-match, length);␊ |
| 1294 | do { putc(s->window[start++], stderr); } while (--length != 0);␊ |
| 1295 | }␊ |
| 1296 | }␊ |
| 1297 | #else␊ |
| 1298 | # define check_match(s, start, match, length)␊ |
| 1299 | #endif /* DEBUG */␊ |
| 1300 | ␊ |
| 1301 | /* ===========================================================================␊ |
| 1302 | * Fill the window when the lookahead becomes insufficient.␊ |
| 1303 | * Updates strstart and lookahead.␊ |
| 1304 | *␊ |
| 1305 | * IN assertion: lookahead < MIN_LOOKAHEAD␊ |
| 1306 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD␊ |
| 1307 | * At least one byte has been read, or avail_in == 0; reads are␊ |
| 1308 | * performed for at least two bytes (required for the zip translate_eol␊ |
| 1309 | * option -- not supported here).␊ |
| 1310 | */␊ |
| 1311 | local void fill_window(s)␊ |
| 1312 | deflate_state *s;␊ |
| 1313 | {␊ |
| 1314 | register unsigned n, m;␊ |
| 1315 | register Posf *p;␊ |
| 1316 | unsigned more; /* Amount of free space at the end of the window. */␊ |
| 1317 | uInt wsize = s->w_size;␊ |
| 1318 | ␊ |
| 1319 | do {␊ |
| 1320 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);␊ |
| 1321 | ␊ |
| 1322 | /* Deal with !@#$% 64K limit: */␊ |
| 1323 | if (sizeof(int) <= 2) {␊ |
| 1324 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) {␊ |
| 1325 | more = wsize;␊ |
| 1326 | ␊ |
| 1327 | } else if (more == (unsigned)(-1)) {␊ |
| 1328 | /* Very unlikely, but possible on 16 bit machine if␊ |
| 1329 | * strstart == 0 && lookahead == 1 (input done a byte at time)␊ |
| 1330 | */␊ |
| 1331 | more--;␊ |
| 1332 | }␊ |
| 1333 | }␊ |
| 1334 | ␊ |
| 1335 | /* If the window is almost full and there is insufficient lookahead,␊ |
| 1336 | * move the upper half to the lower one to make room in the upper half.␊ |
| 1337 | */␊ |
| 1338 | if (s->strstart >= wsize+MAX_DIST(s)) {␊ |
| 1339 | ␊ |
| 1340 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize);␊ |
| 1341 | s->match_start -= wsize;␊ |
| 1342 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */␊ |
| 1343 | s->block_start -= (long) wsize;␊ |
| 1344 | ␊ |
| 1345 | /* Slide the hash table (could be avoided with 32 bit values␊ |
| 1346 | at the expense of memory usage). We slide even when level == 0␊ |
| 1347 | to keep the hash table consistent if we switch back to level > 0␊ |
| 1348 | later. (Using level 0 permanently is not an optimal usage of␊ |
| 1349 | zlib, so we don't care about this pathological case.)␊ |
| 1350 | */␊ |
| 1351 | n = s->hash_size;␊ |
| 1352 | p = &s->head[n];␊ |
| 1353 | do {␊ |
| 1354 | m = *--p;␊ |
| 1355 | *p = (Pos)(m >= wsize ? m-wsize : NIL);␊ |
| 1356 | } while (--n);␊ |
| 1357 | ␊ |
| 1358 | n = wsize;␊ |
| 1359 | #ifndef FASTEST␊ |
| 1360 | p = &s->prev[n];␊ |
| 1361 | do {␊ |
| 1362 | m = *--p;␊ |
| 1363 | *p = (Pos)(m >= wsize ? m-wsize : NIL);␊ |
| 1364 | /* If n is not on any hash chain, prev[n] is garbage but␊ |
| 1365 | * its value will never be used.␊ |
| 1366 | */␊ |
| 1367 | } while (--n);␊ |
| 1368 | #endif␊ |
| 1369 | more += wsize;␊ |
| 1370 | }␊ |
| 1371 | if (s->strm->avail_in == 0) return;␊ |
| 1372 | ␊ |
| 1373 | /* If there was no sliding:␊ |
| 1374 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&␊ |
| 1375 | * more == window_size - lookahead - strstart␊ |
| 1376 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)␊ |
| 1377 | * => more >= window_size - 2*WSIZE + 2␊ |
| 1378 | * In the BIG_MEM or MMAP case (not yet supported),␊ |
| 1379 | * window_size == input_size + MIN_LOOKAHEAD &&␊ |
| 1380 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.␊ |
| 1381 | * Otherwise, window_size == 2*WSIZE so more >= 2.␊ |
| 1382 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2.␊ |
| 1383 | */␊ |
| 1384 | Assert(more >= 2, "more < 2");␊ |
| 1385 | ␊ |
| 1386 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);␊ |
| 1387 | s->lookahead += n;␊ |
| 1388 | ␊ |
| 1389 | /* Initialize the hash value now that we have some input: */␊ |
| 1390 | if (s->lookahead >= MIN_MATCH) {␊ |
| 1391 | s->ins_h = s->window[s->strstart];␊ |
| 1392 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);␊ |
| 1393 | #if MIN_MATCH != 3␊ |
| 1394 | Call UPDATE_HASH() MIN_MATCH-3 more times␊ |
| 1395 | #endif␊ |
| 1396 | }␊ |
| 1397 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,␊ |
| 1398 | * but this is not important since only literal bytes will be emitted.␊ |
| 1399 | */␊ |
| 1400 | ␊ |
| 1401 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);␊ |
| 1402 | ␊ |
| 1403 | /* If the WIN_INIT bytes after the end of the current data have never been␊ |
| 1404 | * written, then zero those bytes in order to avoid memory check reports of␊ |
| 1405 | * the use of uninitialized (or uninitialised as Julian writes) bytes by␊ |
| 1406 | * the longest match routines. Update the high water mark for the next␊ |
| 1407 | * time through here. WIN_INIT is set to MAX_MATCH since the longest match␊ |
| 1408 | * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.␊ |
| 1409 | */␊ |
| 1410 | if (s->high_water < s->window_size) {␊ |
| 1411 | ulg curr = s->strstart + (ulg)(s->lookahead);␊ |
| 1412 | ulg init;␊ |
| 1413 | ␊ |
| 1414 | if (s->high_water < curr) {␊ |
| 1415 | /* Previous high water mark below current data -- zero WIN_INIT␊ |
| 1416 | * bytes or up to end of window, whichever is less.␊ |
| 1417 | */␊ |
| 1418 | init = s->window_size - curr;␊ |
| 1419 | if (init > WIN_INIT)␊ |
| 1420 | init = WIN_INIT;␊ |
| 1421 | zmemzero(s->window + curr, (unsigned)init);␊ |
| 1422 | s->high_water = curr + init;␊ |
| 1423 | }␊ |
| 1424 | else if (s->high_water < (ulg)curr + WIN_INIT) {␊ |
| 1425 | /* High water mark at or above current data, but below current data␊ |
| 1426 | * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up␊ |
| 1427 | * to end of window, whichever is less.␊ |
| 1428 | */␊ |
| 1429 | init = (ulg)curr + WIN_INIT - s->high_water;␊ |
| 1430 | if (init > s->window_size - s->high_water)␊ |
| 1431 | init = s->window_size - s->high_water;␊ |
| 1432 | zmemzero(s->window + s->high_water, (unsigned)init);␊ |
| 1433 | s->high_water += init;␊ |
| 1434 | }␊ |
| 1435 | }␊ |
| 1436 | }␊ |
| 1437 | ␊ |
| 1438 | /* ===========================================================================␊ |
| 1439 | * Flush the current block, with given end-of-file flag.␊ |
| 1440 | * IN assertion: strstart is set to the end of the current match.␊ |
| 1441 | */␊ |
| 1442 | #define FLUSH_BLOCK_ONLY(s, last) { \␊ |
| 1443 | _tr_flush_block(s, (s->block_start >= 0L ? \␊ |
| 1444 | (charf *)&s->window[(unsigned)s->block_start] : \␊ |
| 1445 | (charf *)Z_NULL), \␊ |
| 1446 | (ulg)((long)s->strstart - s->block_start), \␊ |
| 1447 | (last)); \␊ |
| 1448 | s->block_start = s->strstart; \␊ |
| 1449 | flush_pending(s->strm); \␊ |
| 1450 | Tracev((stderr,"[FLUSH]")); \␊ |
| 1451 | }␊ |
| 1452 | ␊ |
| 1453 | /* Same but force premature exit if necessary. */␊ |
| 1454 | #define FLUSH_BLOCK(s, last) { \␊ |
| 1455 | FLUSH_BLOCK_ONLY(s, last); \␊ |
| 1456 | if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \␊ |
| 1457 | }␊ |
| 1458 | ␊ |
| 1459 | /* ===========================================================================␊ |
| 1460 | * Copy without compression as much as possible from the input stream, return␊ |
| 1461 | * the current block state.␊ |
| 1462 | * This function does not insert new strings in the dictionary since␊ |
| 1463 | * uncompressible data is probably not useful. This function is used␊ |
| 1464 | * only for the level=0 compression option.␊ |
| 1465 | * NOTE: this function should be optimized to avoid extra copying from␊ |
| 1466 | * window to pending_buf.␊ |
| 1467 | */␊ |
| 1468 | local block_state deflate_stored(s, flush)␊ |
| 1469 | deflate_state *s;␊ |
| 1470 | int flush;␊ |
| 1471 | {␊ |
| 1472 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited␊ |
| 1473 | * to pending_buf_size, and each stored block has a 5 byte header:␊ |
| 1474 | */␊ |
| 1475 | ulg max_block_size = 0xffff;␊ |
| 1476 | ulg max_start;␊ |
| 1477 | ␊ |
| 1478 | if (max_block_size > s->pending_buf_size - 5) {␊ |
| 1479 | max_block_size = s->pending_buf_size - 5;␊ |
| 1480 | }␊ |
| 1481 | ␊ |
| 1482 | /* Copy as much as possible from input to output: */␊ |
| 1483 | for (;;) {␊ |
| 1484 | /* Fill the window as much as possible: */␊ |
| 1485 | if (s->lookahead <= 1) {␊ |
| 1486 | ␊ |
| 1487 | Assert(s->strstart < s->w_size+MAX_DIST(s) ||␊ |
| 1488 | s->block_start >= (long)s->w_size, "slide too late");␊ |
| 1489 | ␊ |
| 1490 | fill_window(s);␊ |
| 1491 | if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;␊ |
| 1492 | ␊ |
| 1493 | if (s->lookahead == 0) break; /* flush the current block */␊ |
| 1494 | }␊ |
| 1495 | Assert(s->block_start >= 0L, "block gone");␊ |
| 1496 | ␊ |
| 1497 | s->strstart += s->lookahead;␊ |
| 1498 | s->lookahead = 0;␊ |
| 1499 | ␊ |
| 1500 | /* Emit a stored block if pending_buf will be full: */␊ |
| 1501 | max_start = s->block_start + max_block_size;␊ |
| 1502 | if (s->strstart == 0 || (ulg)s->strstart >= max_start) {␊ |
| 1503 | /* strstart == 0 is possible when wraparound on 16-bit machine */␊ |
| 1504 | s->lookahead = (uInt)(s->strstart - max_start);␊ |
| 1505 | s->strstart = (uInt)max_start;␊ |
| 1506 | FLUSH_BLOCK(s, 0);␊ |
| 1507 | }␊ |
| 1508 | /* Flush if we may have to slide, otherwise block_start may become␊ |
| 1509 | * negative and the data will be gone:␊ |
| 1510 | */␊ |
| 1511 | if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {␊ |
| 1512 | FLUSH_BLOCK(s, 0);␊ |
| 1513 | }␊ |
| 1514 | }␊ |
| 1515 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
| 1516 | return flush == Z_FINISH ? finish_done : block_done;␊ |
| 1517 | }␊ |
| 1518 | ␊ |
| 1519 | /* ===========================================================================␊ |
| 1520 | * Compress as much as possible from the input stream, return the current␊ |
| 1521 | * block state.␊ |
| 1522 | * This function does not perform lazy evaluation of matches and inserts␊ |
| 1523 | * new strings in the dictionary only for unmatched strings or for short␊ |
| 1524 | * matches. It is used only for the fast compression options.␊ |
| 1525 | */␊ |
| 1526 | local block_state deflate_fast(s, flush)␊ |
| 1527 | deflate_state *s;␊ |
| 1528 | int flush;␊ |
| 1529 | {␊ |
| 1530 | IPos hash_head; /* head of the hash chain */␊ |
| 1531 | int bflush; /* set if current block must be flushed */␊ |
| 1532 | ␊ |
| 1533 | for (;;) {␊ |
| 1534 | /* Make sure that we always have enough lookahead, except␊ |
| 1535 | * at the end of the input file. We need MAX_MATCH bytes␊ |
| 1536 | * for the next match, plus MIN_MATCH bytes to insert the␊ |
| 1537 | * string following the next match.␊ |
| 1538 | */␊ |
| 1539 | if (s->lookahead < MIN_LOOKAHEAD) {␊ |
| 1540 | fill_window(s);␊ |
| 1541 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {␊ |
| 1542 | return need_more;␊ |
| 1543 | }␊ |
| 1544 | if (s->lookahead == 0) break; /* flush the current block */␊ |
| 1545 | }␊ |
| 1546 | ␊ |
| 1547 | /* Insert the string window[strstart .. strstart+2] in the␊ |
| 1548 | * dictionary, and set hash_head to the head of the hash chain:␊ |
| 1549 | */␊ |
| 1550 | hash_head = NIL;␊ |
| 1551 | if (s->lookahead >= MIN_MATCH) {␊ |
| 1552 | INSERT_STRING(s, s->strstart, hash_head);␊ |
| 1553 | }␊ |
| 1554 | ␊ |
| 1555 | /* Find the longest match, discarding those <= prev_length.␊ |
| 1556 | * At this point we have always match_length < MIN_MATCH␊ |
| 1557 | */␊ |
| 1558 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {␊ |
| 1559 | /* To simplify the code, we prevent matches with the string␊ |
| 1560 | * of window index 0 (in particular we have to avoid a match␊ |
| 1561 | * of the string with itself at the start of the input file).␊ |
| 1562 | */␊ |
| 1563 | s->match_length = longest_match (s, hash_head);␊ |
| 1564 | /* longest_match() sets match_start */␊ |
| 1565 | }␊ |
| 1566 | if (s->match_length >= MIN_MATCH) {␊ |
| 1567 | check_match(s, s->strstart, s->match_start, s->match_length);␊ |
| 1568 | ␊ |
| 1569 | _tr_tally_dist(s, s->strstart - s->match_start,␊ |
| 1570 | s->match_length - MIN_MATCH, bflush);␊ |
| 1571 | ␊ |
| 1572 | s->lookahead -= s->match_length;␊ |
| 1573 | ␊ |
| 1574 | /* Insert new strings in the hash table only if the match length␊ |
| 1575 | * is not too large. This saves time but degrades compression.␊ |
| 1576 | */␊ |
| 1577 | #ifndef FASTEST␊ |
| 1578 | if (s->match_length <= s->max_insert_length &&␊ |
| 1579 | s->lookahead >= MIN_MATCH) {␊ |
| 1580 | s->match_length--; /* string at strstart already in table */␊ |
| 1581 | do {␊ |
| 1582 | s->strstart++;␊ |
| 1583 | INSERT_STRING(s, s->strstart, hash_head);␊ |
| 1584 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are␊ |
| 1585 | * always MIN_MATCH bytes ahead.␊ |
| 1586 | */␊ |
| 1587 | } while (--s->match_length != 0);␊ |
| 1588 | s->strstart++;␊ |
| 1589 | } else␊ |
| 1590 | #endif␊ |
| 1591 | {␊ |
| 1592 | s->strstart += s->match_length;␊ |
| 1593 | s->match_length = 0;␊ |
| 1594 | s->ins_h = s->window[s->strstart];␊ |
| 1595 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);␊ |
| 1596 | #if MIN_MATCH != 3␊ |
| 1597 | Call UPDATE_HASH() MIN_MATCH-3 more times␊ |
| 1598 | #endif␊ |
| 1599 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not␊ |
| 1600 | * matter since it will be recomputed at next deflate call.␊ |
| 1601 | */␊ |
| 1602 | }␊ |
| 1603 | } else {␊ |
| 1604 | /* No match, output a literal byte */␊ |
| 1605 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
| 1606 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
| 1607 | s->lookahead--;␊ |
| 1608 | s->strstart++;␊ |
| 1609 | }␊ |
| 1610 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
| 1611 | }␊ |
| 1612 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
| 1613 | return flush == Z_FINISH ? finish_done : block_done;␊ |
| 1614 | }␊ |
| 1615 | ␊ |
| 1616 | #ifndef FASTEST␊ |
| 1617 | /* ===========================================================================␊ |
| 1618 | * Same as above, but achieves better compression. We use a lazy␊ |
| 1619 | * evaluation for matches: a match is finally adopted only if there is␊ |
| 1620 | * no better match at the next window position.␊ |
| 1621 | */␊ |
| 1622 | local block_state deflate_slow(s, flush)␊ |
| 1623 | deflate_state *s;␊ |
| 1624 | int flush;␊ |
| 1625 | {␊ |
| 1626 | IPos hash_head; /* head of hash chain */␊ |
| 1627 | int bflush; /* set if current block must be flushed */␊ |
| 1628 | ␊ |
| 1629 | /* Process the input block. */␊ |
| 1630 | for (;;) {␊ |
| 1631 | /* Make sure that we always have enough lookahead, except␊ |
| 1632 | * at the end of the input file. We need MAX_MATCH bytes␊ |
| 1633 | * for the next match, plus MIN_MATCH bytes to insert the␊ |
| 1634 | * string following the next match.␊ |
| 1635 | */␊ |
| 1636 | if (s->lookahead < MIN_LOOKAHEAD) {␊ |
| 1637 | fill_window(s);␊ |
| 1638 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {␊ |
| 1639 | return need_more;␊ |
| 1640 | }␊ |
| 1641 | if (s->lookahead == 0) break; /* flush the current block */␊ |
| 1642 | }␊ |
| 1643 | ␊ |
| 1644 | /* Insert the string window[strstart .. strstart+2] in the␊ |
| 1645 | * dictionary, and set hash_head to the head of the hash chain:␊ |
| 1646 | */␊ |
| 1647 | hash_head = NIL;␊ |
| 1648 | if (s->lookahead >= MIN_MATCH) {␊ |
| 1649 | INSERT_STRING(s, s->strstart, hash_head);␊ |
| 1650 | }␊ |
| 1651 | ␊ |
| 1652 | /* Find the longest match, discarding those <= prev_length.␊ |
| 1653 | */␊ |
| 1654 | s->prev_length = s->match_length, s->prev_match = s->match_start;␊ |
| 1655 | s->match_length = MIN_MATCH-1;␊ |
| 1656 | ␊ |
| 1657 | if (hash_head != NIL && s->prev_length < s->max_lazy_match &&␊ |
| 1658 | s->strstart - hash_head <= MAX_DIST(s)) {␊ |
| 1659 | /* To simplify the code, we prevent matches with the string␊ |
| 1660 | * of window index 0 (in particular we have to avoid a match␊ |
| 1661 | * of the string with itself at the start of the input file).␊ |
| 1662 | */␊ |
| 1663 | s->match_length = longest_match (s, hash_head);␊ |
| 1664 | /* longest_match() sets match_start */␊ |
| 1665 | ␊ |
| 1666 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED␊ |
| 1667 | #if TOO_FAR <= 32767␊ |
| 1668 | || (s->match_length == MIN_MATCH &&␊ |
| 1669 | s->strstart - s->match_start > TOO_FAR)␊ |
| 1670 | #endif␊ |
| 1671 | )) {␊ |
| 1672 | ␊ |
| 1673 | /* If prev_match is also MIN_MATCH, match_start is garbage␊ |
| 1674 | * but we will ignore the current match anyway.␊ |
| 1675 | */␊ |
| 1676 | s->match_length = MIN_MATCH-1;␊ |
| 1677 | }␊ |
| 1678 | }␊ |
| 1679 | /* If there was a match at the previous step and the current␊ |
| 1680 | * match is not better, output the previous match:␊ |
| 1681 | */␊ |
| 1682 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {␊ |
| 1683 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;␊ |
| 1684 | /* Do not insert strings in hash table beyond this. */␊ |
| 1685 | ␊ |
| 1686 | check_match(s, s->strstart-1, s->prev_match, s->prev_length);␊ |
| 1687 | ␊ |
| 1688 | _tr_tally_dist(s, s->strstart -1 - s->prev_match,␊ |
| 1689 | s->prev_length - MIN_MATCH, bflush);␊ |
| 1690 | ␊ |
| 1691 | /* Insert in hash table all strings up to the end of the match.␊ |
| 1692 | * strstart-1 and strstart are already inserted. If there is not␊ |
| 1693 | * enough lookahead, the last two strings are not inserted in␊ |
| 1694 | * the hash table.␊ |
| 1695 | */␊ |
| 1696 | s->lookahead -= s->prev_length-1;␊ |
| 1697 | s->prev_length -= 2;␊ |
| 1698 | do {␊ |
| 1699 | if (++s->strstart <= max_insert) {␊ |
| 1700 | INSERT_STRING(s, s->strstart, hash_head);␊ |
| 1701 | }␊ |
| 1702 | } while (--s->prev_length != 0);␊ |
| 1703 | s->match_available = 0;␊ |
| 1704 | s->match_length = MIN_MATCH-1;␊ |
| 1705 | s->strstart++;␊ |
| 1706 | ␊ |
| 1707 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
| 1708 | ␊ |
| 1709 | } else if (s->match_available) {␊ |
| 1710 | /* If there was no match at the previous position, output a␊ |
| 1711 | * single literal. If there was a match but the current match␊ |
| 1712 | * is longer, truncate the previous match to a single literal.␊ |
| 1713 | */␊ |
| 1714 | Tracevv((stderr,"%c", s->window[s->strstart-1]));␊ |
| 1715 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);␊ |
| 1716 | if (bflush) {␊ |
| 1717 | FLUSH_BLOCK_ONLY(s, 0);␊ |
| 1718 | }␊ |
| 1719 | s->strstart++;␊ |
| 1720 | s->lookahead--;␊ |
| 1721 | if (s->strm->avail_out == 0) return need_more;␊ |
| 1722 | } else {␊ |
| 1723 | /* There is no previous match to compare with, wait for␊ |
| 1724 | * the next step to decide.␊ |
| 1725 | */␊ |
| 1726 | s->match_available = 1;␊ |
| 1727 | s->strstart++;␊ |
| 1728 | s->lookahead--;␊ |
| 1729 | }␊ |
| 1730 | }␊ |
| 1731 | Assert (flush != Z_NO_FLUSH, "no flush?");␊ |
| 1732 | if (s->match_available) {␊ |
| 1733 | Tracevv((stderr,"%c", s->window[s->strstart-1]));␊ |
| 1734 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);␊ |
| 1735 | s->match_available = 0;␊ |
| 1736 | }␊ |
| 1737 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
| 1738 | return flush == Z_FINISH ? finish_done : block_done;␊ |
| 1739 | }␊ |
| 1740 | #endif /* FASTEST */␊ |
| 1741 | ␊ |
| 1742 | /* ===========================================================================␊ |
| 1743 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance␊ |
| 1744 | * one. Do not maintain a hash table. (It will be regenerated if this run of␊ |
| 1745 | * deflate switches away from Z_RLE.)␊ |
| 1746 | */␊ |
| 1747 | local block_state deflate_rle(s, flush)␊ |
| 1748 | deflate_state *s;␊ |
| 1749 | int flush;␊ |
| 1750 | {␊ |
| 1751 | int bflush; /* set if current block must be flushed */␊ |
| 1752 | uInt prev; /* byte at distance one to match */␊ |
| 1753 | Bytef *scan, *strend; /* scan goes up to strend for length of run */␊ |
| 1754 | ␊ |
| 1755 | for (;;) {␊ |
| 1756 | /* Make sure that we always have enough lookahead, except␊ |
| 1757 | * at the end of the input file. We need MAX_MATCH bytes␊ |
| 1758 | * for the longest encodable run.␊ |
| 1759 | */␊ |
| 1760 | if (s->lookahead < MAX_MATCH) {␊ |
| 1761 | fill_window(s);␊ |
| 1762 | if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {␊ |
| 1763 | return need_more;␊ |
| 1764 | }␊ |
| 1765 | if (s->lookahead == 0) break; /* flush the current block */␊ |
| 1766 | }␊ |
| 1767 | ␊ |
| 1768 | /* See how many times the previous byte repeats */␊ |
| 1769 | s->match_length = 0;␊ |
| 1770 | if (s->lookahead >= MIN_MATCH && s->strstart > 0) {␊ |
| 1771 | scan = s->window + s->strstart - 1;␊ |
| 1772 | prev = *scan;␊ |
| 1773 | if (prev == *++scan && prev == *++scan && prev == *++scan) {␊ |
| 1774 | strend = s->window + s->strstart + MAX_MATCH;␊ |
| 1775 | do {␊ |
| 1776 | } while (prev == *++scan && prev == *++scan &&␊ |
| 1777 | prev == *++scan && prev == *++scan &&␊ |
| 1778 | prev == *++scan && prev == *++scan &&␊ |
| 1779 | prev == *++scan && prev == *++scan &&␊ |
| 1780 | scan < strend);␊ |
| 1781 | s->match_length = MAX_MATCH - (int)(strend - scan);␊ |
| 1782 | if (s->match_length > s->lookahead)␊ |
| 1783 | s->match_length = s->lookahead;␊ |
| 1784 | }␊ |
| 1785 | }␊ |
| 1786 | ␊ |
| 1787 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */␊ |
| 1788 | if (s->match_length >= MIN_MATCH) {␊ |
| 1789 | check_match(s, s->strstart, s->strstart - 1, s->match_length);␊ |
| 1790 | ␊ |
| 1791 | _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);␊ |
| 1792 | ␊ |
| 1793 | s->lookahead -= s->match_length;␊ |
| 1794 | s->strstart += s->match_length;␊ |
| 1795 | s->match_length = 0;␊ |
| 1796 | } else {␊ |
| 1797 | /* No match, output a literal byte */␊ |
| 1798 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
| 1799 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
| 1800 | s->lookahead--;␊ |
| 1801 | s->strstart++;␊ |
| 1802 | }␊ |
| 1803 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
| 1804 | }␊ |
| 1805 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
| 1806 | return flush == Z_FINISH ? finish_done : block_done;␊ |
| 1807 | }␊ |
| 1808 | ␊ |
| 1809 | /* ===========================================================================␊ |
| 1810 | * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.␊ |
| 1811 | * (It will be regenerated if this run of deflate switches away from Huffman.)␊ |
| 1812 | */␊ |
| 1813 | local block_state deflate_huff(s, flush)␊ |
| 1814 | deflate_state *s;␊ |
| 1815 | int flush;␊ |
| 1816 | {␊ |
| 1817 | int bflush; /* set if current block must be flushed */␊ |
| 1818 | ␊ |
| 1819 | for (;;) {␊ |
| 1820 | /* Make sure that we have a literal to write. */␊ |
| 1821 | if (s->lookahead == 0) {␊ |
| 1822 | fill_window(s);␊ |
| 1823 | if (s->lookahead == 0) {␊ |
| 1824 | if (flush == Z_NO_FLUSH)␊ |
| 1825 | return need_more;␊ |
| 1826 | break; /* flush the current block */␊ |
| 1827 | }␊ |
| 1828 | }␊ |
| 1829 | ␊ |
| 1830 | /* Output a literal byte */␊ |
| 1831 | s->match_length = 0;␊ |
| 1832 | Tracevv((stderr,"%c", s->window[s->strstart]));␊ |
| 1833 | _tr_tally_lit (s, s->window[s->strstart], bflush);␊ |
| 1834 | s->lookahead--;␊ |
| 1835 | s->strstart++;␊ |
| 1836 | if (bflush) FLUSH_BLOCK(s, 0);␊ |
| 1837 | }␊ |
| 1838 | FLUSH_BLOCK(s, flush == Z_FINISH);␊ |
| 1839 | return flush == Z_FINISH ? finish_done : block_done;␊ |
| 1840 | }␊ |
| 1841 | |
