1.1 --- a/sourcepawn/jit/zlib/deflate.c Fri Jul 11 06:51:21 2008 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,1736 +0,0 @@
1.4 -/* deflate.c -- compress data using the deflation algorithm
1.5 - * Copyright (C) 1995-2005 Jean-loup Gailly.
1.6 - * For conditions of distribution and use, see copyright notice in zlib.h
1.7 - */
1.8 -
1.9 -/*
1.10 - * ALGORITHM
1.11 - *
1.12 - * The "deflation" process depends on being able to identify portions
1.13 - * of the input text which are identical to earlier input (within a
1.14 - * sliding window trailing behind the input currently being processed).
1.15 - *
1.16 - * The most straightforward technique turns out to be the fastest for
1.17 - * most input files: try all possible matches and select the longest.
1.18 - * The key feature of this algorithm is that insertions into the string
1.19 - * dictionary are very simple and thus fast, and deletions are avoided
1.20 - * completely. Insertions are performed at each input character, whereas
1.21 - * string matches are performed only when the previous match ends. So it
1.22 - * is preferable to spend more time in matches to allow very fast string
1.23 - * insertions and avoid deletions. The matching algorithm for small
1.24 - * strings is inspired from that of Rabin & Karp. A brute force approach
1.25 - * is used to find longer strings when a small match has been found.
1.26 - * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
1.27 - * (by Leonid Broukhis).
1.28 - * A previous version of this file used a more sophisticated algorithm
1.29 - * (by Fiala and Greene) which is guaranteed to run in linear amortized
1.30 - * time, but has a larger average cost, uses more memory and is patented.
1.31 - * However the F&G algorithm may be faster for some highly redundant
1.32 - * files if the parameter max_chain_length (described below) is too large.
1.33 - *
1.34 - * ACKNOWLEDGEMENTS
1.35 - *
1.36 - * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
1.37 - * I found it in 'freeze' written by Leonid Broukhis.
1.38 - * Thanks to many people for bug reports and testing.
1.39 - *
1.40 - * REFERENCES
1.41 - *
1.42 - * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
1.43 - * Available in http://www.ietf.org/rfc/rfc1951.txt
1.44 - *
1.45 - * A description of the Rabin and Karp algorithm is given in the book
1.46 - * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
1.47 - *
1.48 - * Fiala,E.R., and Greene,D.H.
1.49 - * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
1.50 - *
1.51 - */
1.52 -
1.53 -/* @(#) $Id$ */
1.54 -
1.55 -#include "deflate.h"
1.56 -
1.57 -const char deflate_copyright[] =
1.58 - " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly ";
1.59 -/*
1.60 - If you use the zlib library in a product, an acknowledgment is welcome
1.61 - in the documentation of your product. If for some reason you cannot
1.62 - include such an acknowledgment, I would appreciate that you keep this
1.63 - copyright string in the executable of your product.
1.64 - */
1.65 -
1.66 -/* ===========================================================================
1.67 - * Function prototypes.
1.68 - */
1.69 -typedef enum {
1.70 - need_more, /* block not completed, need more input or more output */
1.71 - block_done, /* block flush performed */
1.72 - finish_started, /* finish started, need only more output at next deflate */
1.73 - finish_done /* finish done, accept no more input or output */
1.74 -} block_state;
1.75 -
1.76 -typedef block_state (*compress_func) OF((deflate_state *s, int flush));
1.77 -/* Compression function. Returns the block state after the call. */
1.78 -
1.79 -local void fill_window OF((deflate_state *s));
1.80 -local block_state deflate_stored OF((deflate_state *s, int flush));
1.81 -local block_state deflate_fast OF((deflate_state *s, int flush));
1.82 -#ifndef FASTEST
1.83 -local block_state deflate_slow OF((deflate_state *s, int flush));
1.84 -#endif
1.85 -local void lm_init OF((deflate_state *s));
1.86 -local void putShortMSB OF((deflate_state *s, uInt b));
1.87 -local void flush_pending OF((z_streamp strm));
1.88 -local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
1.89 -#ifndef FASTEST
1.90 -#ifdef ASMV
1.91 - void match_init OF((void)); /* asm code initialization */
1.92 - uInt longest_match OF((deflate_state *s, IPos cur_match));
1.93 -#else
1.94 -local uInt longest_match OF((deflate_state *s, IPos cur_match));
1.95 -#endif
1.96 -#endif
1.97 -local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
1.98 -
1.99 -#ifdef DEBUG
1.100 -local void check_match OF((deflate_state *s, IPos start, IPos match,
1.101 - int length));
1.102 -#endif
1.103 -
1.104 -/* ===========================================================================
1.105 - * Local data
1.106 - */
1.107 -
1.108 -#define NIL 0
1.109 -/* Tail of hash chains */
1.110 -
1.111 -#ifndef TOO_FAR
1.112 -# define TOO_FAR 4096
1.113 -#endif
1.114 -/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
1.115 -
1.116 -#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
1.117 -/* Minimum amount of lookahead, except at the end of the input file.
1.118 - * See deflate.c for comments about the MIN_MATCH+1.
1.119 - */
1.120 -
1.121 -/* Values for max_lazy_match, good_match and max_chain_length, depending on
1.122 - * the desired pack level (0..9). The values given below have been tuned to
1.123 - * exclude worst case performance for pathological files. Better values may be
1.124 - * found for specific files.
1.125 - */
1.126 -typedef struct config_s {
1.127 - ush good_length; /* reduce lazy search above this match length */
1.128 - ush max_lazy; /* do not perform lazy search above this match length */
1.129 - ush nice_length; /* quit search above this match length */
1.130 - ush max_chain;
1.131 - compress_func func;
1.132 -} config;
1.133 -
1.134 -#ifdef FASTEST
1.135 -local const config configuration_table[2] = {
1.136 -/* good lazy nice chain */
1.137 -/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
1.138 -/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
1.139 -#else
1.140 -local const config configuration_table[10] = {
1.141 -/* good lazy nice chain */
1.142 -/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
1.143 -/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
1.144 -/* 2 */ {4, 5, 16, 8, deflate_fast},
1.145 -/* 3 */ {4, 6, 32, 32, deflate_fast},
1.146 -
1.147 -/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
1.148 -/* 5 */ {8, 16, 32, 32, deflate_slow},
1.149 -/* 6 */ {8, 16, 128, 128, deflate_slow},
1.150 -/* 7 */ {8, 32, 128, 256, deflate_slow},
1.151 -/* 8 */ {32, 128, 258, 1024, deflate_slow},
1.152 -/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
1.153 -#endif
1.154 -
1.155 -/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
1.156 - * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
1.157 - * meaning.
1.158 - */
1.159 -
1.160 -#define EQUAL 0
1.161 -/* result of memcmp for equal strings */
1.162 -
1.163 -#ifndef NO_DUMMY_DECL
1.164 -struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
1.165 -#endif
1.166 -
1.167 -/* ===========================================================================
1.168 - * Update a hash value with the given input byte
1.169 - * IN assertion: all calls to to UPDATE_HASH are made with consecutive
1.170 - * input characters, so that a running hash key can be computed from the
1.171 - * previous key instead of complete recalculation each time.
1.172 - */
1.173 -#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
1.174 -
1.175 -
1.176 -/* ===========================================================================
1.177 - * Insert string str in the dictionary and set match_head to the previous head
1.178 - * of the hash chain (the most recent string with same hash key). Return
1.179 - * the previous length of the hash chain.
1.180 - * If this file is compiled with -DFASTEST, the compression level is forced
1.181 - * to 1, and no hash chains are maintained.
1.182 - * IN assertion: all calls to to INSERT_STRING are made with consecutive
1.183 - * input characters and the first MIN_MATCH bytes of str are valid
1.184 - * (except for the last MIN_MATCH-1 bytes of the input file).
1.185 - */
1.186 -#ifdef FASTEST
1.187 -#define INSERT_STRING(s, str, match_head) \
1.188 - (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
1.189 - match_head = s->head[s->ins_h], \
1.190 - s->head[s->ins_h] = (Pos)(str))
1.191 -#else
1.192 -#define INSERT_STRING(s, str, match_head) \
1.193 - (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
1.194 - match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
1.195 - s->head[s->ins_h] = (Pos)(str))
1.196 -#endif
1.197 -
1.198 -/* ===========================================================================
1.199 - * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
1.200 - * prev[] will be initialized on the fly.
1.201 - */
1.202 -#define CLEAR_HASH(s) \
1.203 - s->head[s->hash_size-1] = NIL; \
1.204 - zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
1.205 -
1.206 -/* ========================================================================= */
1.207 -int ZEXPORT deflateInit_(strm, level, version, stream_size)
1.208 - z_streamp strm;
1.209 - int level;
1.210 - const char *version;
1.211 - int stream_size;
1.212 -{
1.213 - return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
1.214 - Z_DEFAULT_STRATEGY, version, stream_size);
1.215 - /* To do: ignore strm->next_in if we use it as window */
1.216 -}
1.217 -
1.218 -/* ========================================================================= */
1.219 -int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
1.220 - version, stream_size)
1.221 - z_streamp strm;
1.222 - int level;
1.223 - int method;
1.224 - int windowBits;
1.225 - int memLevel;
1.226 - int strategy;
1.227 - const char *version;
1.228 - int stream_size;
1.229 -{
1.230 - deflate_state *s;
1.231 - int wrap = 1;
1.232 - static const char my_version[] = ZLIB_VERSION;
1.233 -
1.234 - ushf *overlay;
1.235 - /* We overlay pending_buf and d_buf+l_buf. This works since the average
1.236 - * output size for (length,distance) codes is <= 24 bits.
1.237 - */
1.238 -
1.239 - if (version == Z_NULL || version[0] != my_version[0] ||
1.240 - stream_size != sizeof(z_stream)) {
1.241 - return Z_VERSION_ERROR;
1.242 - }
1.243 - if (strm == Z_NULL) return Z_STREAM_ERROR;
1.244 -
1.245 - strm->msg = Z_NULL;
1.246 - if (strm->zalloc == (alloc_func)0) {
1.247 - strm->zalloc = zcalloc;
1.248 - strm->opaque = (voidpf)0;
1.249 - }
1.250 - if (strm->zfree == (free_func)0) strm->zfree = zcfree;
1.251 -
1.252 -#ifdef FASTEST
1.253 - if (level != 0) level = 1;
1.254 -#else
1.255 - if (level == Z_DEFAULT_COMPRESSION) level = 6;
1.256 -#endif
1.257 -
1.258 - if (windowBits < 0) { /* suppress zlib wrapper */
1.259 - wrap = 0;
1.260 - windowBits = -windowBits;
1.261 - }
1.262 -#ifdef GZIP
1.263 - else if (windowBits > 15) {
1.264 - wrap = 2; /* write gzip wrapper instead */
1.265 - windowBits -= 16;
1.266 - }
1.267 -#endif
1.268 - if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
1.269 - windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
1.270 - strategy < 0 || strategy > Z_FIXED) {
1.271 - return Z_STREAM_ERROR;
1.272 - }
1.273 - if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
1.274 - s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
1.275 - if (s == Z_NULL) return Z_MEM_ERROR;
1.276 - strm->state = (struct internal_state FAR *)s;
1.277 - s->strm = strm;
1.278 -
1.279 - s->wrap = wrap;
1.280 - s->gzhead = Z_NULL;
1.281 - s->w_bits = windowBits;
1.282 - s->w_size = 1 << s->w_bits;
1.283 - s->w_mask = s->w_size - 1;
1.284 -
1.285 - s->hash_bits = memLevel + 7;
1.286 - s->hash_size = 1 << s->hash_bits;
1.287 - s->hash_mask = s->hash_size - 1;
1.288 - s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
1.289 -
1.290 - s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
1.291 - s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
1.292 - s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
1.293 -
1.294 - s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
1.295 -
1.296 - overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
1.297 - s->pending_buf = (uchf *) overlay;
1.298 - s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
1.299 -
1.300 - if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
1.301 - s->pending_buf == Z_NULL) {
1.302 - s->status = FINISH_STATE;
1.303 - strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
1.304 - deflateEnd (strm);
1.305 - return Z_MEM_ERROR;
1.306 - }
1.307 - s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
1.308 - s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
1.309 -
1.310 - s->level = level;
1.311 - s->strategy = strategy;
1.312 - s->method = (Byte)method;
1.313 -
1.314 - return deflateReset(strm);
1.315 -}
1.316 -
1.317 -/* ========================================================================= */
1.318 -int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
1.319 - z_streamp strm;
1.320 - const Bytef *dictionary;
1.321 - uInt dictLength;
1.322 -{
1.323 - deflate_state *s;
1.324 - uInt length = dictLength;
1.325 - uInt n;
1.326 - IPos hash_head = 0;
1.327 -
1.328 - if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
1.329 - strm->state->wrap == 2 ||
1.330 - (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
1.331 - return Z_STREAM_ERROR;
1.332 -
1.333 - s = strm->state;
1.334 - if (s->wrap)
1.335 - strm->adler = adler32(strm->adler, dictionary, dictLength);
1.336 -
1.337 - if (length < MIN_MATCH) return Z_OK;
1.338 - if (length > MAX_DIST(s)) {
1.339 - length = MAX_DIST(s);
1.340 - dictionary += dictLength - length; /* use the tail of the dictionary */
1.341 - }
1.342 - zmemcpy(s->window, dictionary, length);
1.343 - s->strstart = length;
1.344 - s->block_start = (long)length;
1.345 -
1.346 - /* Insert all strings in the hash table (except for the last two bytes).
1.347 - * s->lookahead stays null, so s->ins_h will be recomputed at the next
1.348 - * call of fill_window.
1.349 - */
1.350 - s->ins_h = s->window[0];
1.351 - UPDATE_HASH(s, s->ins_h, s->window[1]);
1.352 - for (n = 0; n <= length - MIN_MATCH; n++) {
1.353 - INSERT_STRING(s, n, hash_head);
1.354 - }
1.355 - if (hash_head) hash_head = 0; /* to make compiler happy */
1.356 - return Z_OK;
1.357 -}
1.358 -
1.359 -/* ========================================================================= */
1.360 -int ZEXPORT deflateReset (strm)
1.361 - z_streamp strm;
1.362 -{
1.363 - deflate_state *s;
1.364 -
1.365 - if (strm == Z_NULL || strm->state == Z_NULL ||
1.366 - strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
1.367 - return Z_STREAM_ERROR;
1.368 - }
1.369 -
1.370 - strm->total_in = strm->total_out = 0;
1.371 - strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
1.372 - strm->data_type = Z_UNKNOWN;
1.373 -
1.374 - s = (deflate_state *)strm->state;
1.375 - s->pending = 0;
1.376 - s->pending_out = s->pending_buf;
1.377 -
1.378 - if (s->wrap < 0) {
1.379 - s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
1.380 - }
1.381 - s->status = s->wrap ? INIT_STATE : BUSY_STATE;
1.382 - strm->adler =
1.383 -#ifdef GZIP
1.384 - s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
1.385 -#endif
1.386 - adler32(0L, Z_NULL, 0);
1.387 - s->last_flush = Z_NO_FLUSH;
1.388 -
1.389 - _tr_init(s);
1.390 - lm_init(s);
1.391 -
1.392 - return Z_OK;
1.393 -}
1.394 -
1.395 -/* ========================================================================= */
1.396 -int ZEXPORT deflateSetHeader (strm, head)
1.397 - z_streamp strm;
1.398 - gz_headerp head;
1.399 -{
1.400 - if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1.401 - if (strm->state->wrap != 2) return Z_STREAM_ERROR;
1.402 - strm->state->gzhead = head;
1.403 - return Z_OK;
1.404 -}
1.405 -
1.406 -/* ========================================================================= */
1.407 -int ZEXPORT deflatePrime (strm, bits, value)
1.408 - z_streamp strm;
1.409 - int bits;
1.410 - int value;
1.411 -{
1.412 - if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1.413 - strm->state->bi_valid = bits;
1.414 - strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
1.415 - return Z_OK;
1.416 -}
1.417 -
1.418 -/* ========================================================================= */
1.419 -int ZEXPORT deflateParams(strm, level, strategy)
1.420 - z_streamp strm;
1.421 - int level;
1.422 - int strategy;
1.423 -{
1.424 - deflate_state *s;
1.425 - compress_func func;
1.426 - int err = Z_OK;
1.427 -
1.428 - if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1.429 - s = strm->state;
1.430 -
1.431 -#ifdef FASTEST
1.432 - if (level != 0) level = 1;
1.433 -#else
1.434 - if (level == Z_DEFAULT_COMPRESSION) level = 6;
1.435 -#endif
1.436 - if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
1.437 - return Z_STREAM_ERROR;
1.438 - }
1.439 - func = configuration_table[s->level].func;
1.440 -
1.441 - if (func != configuration_table[level].func && strm->total_in != 0) {
1.442 - /* Flush the last buffer: */
1.443 - err = deflate(strm, Z_PARTIAL_FLUSH);
1.444 - }
1.445 - if (s->level != level) {
1.446 - s->level = level;
1.447 - s->max_lazy_match = configuration_table[level].max_lazy;
1.448 - s->good_match = configuration_table[level].good_length;
1.449 - s->nice_match = configuration_table[level].nice_length;
1.450 - s->max_chain_length = configuration_table[level].max_chain;
1.451 - }
1.452 - s->strategy = strategy;
1.453 - return err;
1.454 -}
1.455 -
1.456 -/* ========================================================================= */
1.457 -int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
1.458 - z_streamp strm;
1.459 - int good_length;
1.460 - int max_lazy;
1.461 - int nice_length;
1.462 - int max_chain;
1.463 -{
1.464 - deflate_state *s;
1.465 -
1.466 - if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1.467 - s = strm->state;
1.468 - s->good_match = good_length;
1.469 - s->max_lazy_match = max_lazy;
1.470 - s->nice_match = nice_length;
1.471 - s->max_chain_length = max_chain;
1.472 - return Z_OK;
1.473 -}
1.474 -
1.475 -/* =========================================================================
1.476 - * For the default windowBits of 15 and memLevel of 8, this function returns
1.477 - * a close to exact, as well as small, upper bound on the compressed size.
1.478 - * They are coded as constants here for a reason--if the #define's are
1.479 - * changed, then this function needs to be changed as well. The return
1.480 - * value for 15 and 8 only works for those exact settings.
1.481 - *
1.482 - * For any setting other than those defaults for windowBits and memLevel,
1.483 - * the value returned is a conservative worst case for the maximum expansion
1.484 - * resulting from using fixed blocks instead of stored blocks, which deflate
1.485 - * can emit on compressed data for some combinations of the parameters.
1.486 - *
1.487 - * This function could be more sophisticated to provide closer upper bounds
1.488 - * for every combination of windowBits and memLevel, as well as wrap.
1.489 - * But even the conservative upper bound of about 14% expansion does not
1.490 - * seem onerous for output buffer allocation.
1.491 - */
1.492 -uLong ZEXPORT deflateBound(strm, sourceLen)
1.493 - z_streamp strm;
1.494 - uLong sourceLen;
1.495 -{
1.496 - deflate_state *s;
1.497 - uLong destLen;
1.498 -
1.499 - /* conservative upper bound */
1.500 - destLen = sourceLen +
1.501 - ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
1.502 -
1.503 - /* if can't get parameters, return conservative bound */
1.504 - if (strm == Z_NULL || strm->state == Z_NULL)
1.505 - return destLen;
1.506 -
1.507 - /* if not default parameters, return conservative bound */
1.508 - s = strm->state;
1.509 - if (s->w_bits != 15 || s->hash_bits != 8 + 7)
1.510 - return destLen;
1.511 -
1.512 - /* default settings: return tight bound for that case */
1.513 - return compressBound(sourceLen);
1.514 -}
1.515 -
1.516 -/* =========================================================================
1.517 - * Put a short in the pending buffer. The 16-bit value is put in MSB order.
1.518 - * IN assertion: the stream state is correct and there is enough room in
1.519 - * pending_buf.
1.520 - */
1.521 -local void putShortMSB (s, b)
1.522 - deflate_state *s;
1.523 - uInt b;
1.524 -{
1.525 - put_byte(s, (Byte)(b >> 8));
1.526 - put_byte(s, (Byte)(b & 0xff));
1.527 -}
1.528 -
1.529 -/* =========================================================================
1.530 - * Flush as much pending output as possible. All deflate() output goes
1.531 - * through this function so some applications may wish to modify it
1.532 - * to avoid allocating a large strm->next_out buffer and copying into it.
1.533 - * (See also read_buf()).
1.534 - */
1.535 -local void flush_pending(strm)
1.536 - z_streamp strm;
1.537 -{
1.538 - unsigned len = strm->state->pending;
1.539 -
1.540 - if (len > strm->avail_out) len = strm->avail_out;
1.541 - if (len == 0) return;
1.542 -
1.543 - zmemcpy(strm->next_out, strm->state->pending_out, len);
1.544 - strm->next_out += len;
1.545 - strm->state->pending_out += len;
1.546 - strm->total_out += len;
1.547 - strm->avail_out -= len;
1.548 - strm->state->pending -= len;
1.549 - if (strm->state->pending == 0) {
1.550 - strm->state->pending_out = strm->state->pending_buf;
1.551 - }
1.552 -}
1.553 -
1.554 -/* ========================================================================= */
1.555 -int ZEXPORT deflate (strm, flush)
1.556 - z_streamp strm;
1.557 - int flush;
1.558 -{
1.559 - int old_flush; /* value of flush param for previous deflate call */
1.560 - deflate_state *s;
1.561 -
1.562 - if (strm == Z_NULL || strm->state == Z_NULL ||
1.563 - flush > Z_FINISH || flush < 0) {
1.564 - return Z_STREAM_ERROR;
1.565 - }
1.566 - s = strm->state;
1.567 -
1.568 - if (strm->next_out == Z_NULL ||
1.569 - (strm->next_in == Z_NULL && strm->avail_in != 0) ||
1.570 - (s->status == FINISH_STATE && flush != Z_FINISH)) {
1.571 - ERR_RETURN(strm, Z_STREAM_ERROR);
1.572 - }
1.573 - if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
1.574 -
1.575 - s->strm = strm; /* just in case */
1.576 - old_flush = s->last_flush;
1.577 - s->last_flush = flush;
1.578 -
1.579 - /* Write the header */
1.580 - if (s->status == INIT_STATE) {
1.581 -#ifdef GZIP
1.582 - if (s->wrap == 2) {
1.583 - strm->adler = crc32(0L, Z_NULL, 0);
1.584 - put_byte(s, 31);
1.585 - put_byte(s, 139);
1.586 - put_byte(s, 8);
1.587 - if (s->gzhead == NULL) {
1.588 - put_byte(s, 0);
1.589 - put_byte(s, 0);
1.590 - put_byte(s, 0);
1.591 - put_byte(s, 0);
1.592 - put_byte(s, 0);
1.593 - put_byte(s, s->level == 9 ? 2 :
1.594 - (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
1.595 - 4 : 0));
1.596 - put_byte(s, OS_CODE);
1.597 - s->status = BUSY_STATE;
1.598 - }
1.599 - else {
1.600 - put_byte(s, (s->gzhead->text ? 1 : 0) +
1.601 - (s->gzhead->hcrc ? 2 : 0) +
1.602 - (s->gzhead->extra == Z_NULL ? 0 : 4) +
1.603 - (s->gzhead->name == Z_NULL ? 0 : 8) +
1.604 - (s->gzhead->comment == Z_NULL ? 0 : 16)
1.605 - );
1.606 - put_byte(s, (Byte)(s->gzhead->time & 0xff));
1.607 - put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
1.608 - put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
1.609 - put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
1.610 - put_byte(s, s->level == 9 ? 2 :
1.611 - (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
1.612 - 4 : 0));
1.613 - put_byte(s, s->gzhead->os & 0xff);
1.614 - if (s->gzhead->extra != NULL) {
1.615 - put_byte(s, s->gzhead->extra_len & 0xff);
1.616 - put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
1.617 - }
1.618 - if (s->gzhead->hcrc)
1.619 - strm->adler = crc32(strm->adler, s->pending_buf,
1.620 - s->pending);
1.621 - s->gzindex = 0;
1.622 - s->status = EXTRA_STATE;
1.623 - }
1.624 - }
1.625 - else
1.626 -#endif
1.627 - {
1.628 - uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
1.629 - uInt level_flags;
1.630 -
1.631 - if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
1.632 - level_flags = 0;
1.633 - else if (s->level < 6)
1.634 - level_flags = 1;
1.635 - else if (s->level == 6)
1.636 - level_flags = 2;
1.637 - else
1.638 - level_flags = 3;
1.639 - header |= (level_flags << 6);
1.640 - if (s->strstart != 0) header |= PRESET_DICT;
1.641 - header += 31 - (header % 31);
1.642 -
1.643 - s->status = BUSY_STATE;
1.644 - putShortMSB(s, header);
1.645 -
1.646 - /* Save the adler32 of the preset dictionary: */
1.647 - if (s->strstart != 0) {
1.648 - putShortMSB(s, (uInt)(strm->adler >> 16));
1.649 - putShortMSB(s, (uInt)(strm->adler & 0xffff));
1.650 - }
1.651 - strm->adler = adler32(0L, Z_NULL, 0);
1.652 - }
1.653 - }
1.654 -#ifdef GZIP
1.655 - if (s->status == EXTRA_STATE) {
1.656 - if (s->gzhead->extra != NULL) {
1.657 - uInt beg = s->pending; /* start of bytes to update crc */
1.658 -
1.659 - while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
1.660 - if (s->pending == s->pending_buf_size) {
1.661 - if (s->gzhead->hcrc && s->pending > beg)
1.662 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.663 - s->pending - beg);
1.664 - flush_pending(strm);
1.665 - beg = s->pending;
1.666 - if (s->pending == s->pending_buf_size)
1.667 - break;
1.668 - }
1.669 - put_byte(s, s->gzhead->extra[s->gzindex]);
1.670 - s->gzindex++;
1.671 - }
1.672 - if (s->gzhead->hcrc && s->pending > beg)
1.673 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.674 - s->pending - beg);
1.675 - if (s->gzindex == s->gzhead->extra_len) {
1.676 - s->gzindex = 0;
1.677 - s->status = NAME_STATE;
1.678 - }
1.679 - }
1.680 - else
1.681 - s->status = NAME_STATE;
1.682 - }
1.683 - if (s->status == NAME_STATE) {
1.684 - if (s->gzhead->name != NULL) {
1.685 - uInt beg = s->pending; /* start of bytes to update crc */
1.686 - int val;
1.687 -
1.688 - do {
1.689 - if (s->pending == s->pending_buf_size) {
1.690 - if (s->gzhead->hcrc && s->pending > beg)
1.691 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.692 - s->pending - beg);
1.693 - flush_pending(strm);
1.694 - beg = s->pending;
1.695 - if (s->pending == s->pending_buf_size) {
1.696 - val = 1;
1.697 - break;
1.698 - }
1.699 - }
1.700 - val = s->gzhead->name[s->gzindex++];
1.701 - put_byte(s, val);
1.702 - } while (val != 0);
1.703 - if (s->gzhead->hcrc && s->pending > beg)
1.704 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.705 - s->pending - beg);
1.706 - if (val == 0) {
1.707 - s->gzindex = 0;
1.708 - s->status = COMMENT_STATE;
1.709 - }
1.710 - }
1.711 - else
1.712 - s->status = COMMENT_STATE;
1.713 - }
1.714 - if (s->status == COMMENT_STATE) {
1.715 - if (s->gzhead->comment != NULL) {
1.716 - uInt beg = s->pending; /* start of bytes to update crc */
1.717 - int val;
1.718 -
1.719 - do {
1.720 - if (s->pending == s->pending_buf_size) {
1.721 - if (s->gzhead->hcrc && s->pending > beg)
1.722 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.723 - s->pending - beg);
1.724 - flush_pending(strm);
1.725 - beg = s->pending;
1.726 - if (s->pending == s->pending_buf_size) {
1.727 - val = 1;
1.728 - break;
1.729 - }
1.730 - }
1.731 - val = s->gzhead->comment[s->gzindex++];
1.732 - put_byte(s, val);
1.733 - } while (val != 0);
1.734 - if (s->gzhead->hcrc && s->pending > beg)
1.735 - strm->adler = crc32(strm->adler, s->pending_buf + beg,
1.736 - s->pending - beg);
1.737 - if (val == 0)
1.738 - s->status = HCRC_STATE;
1.739 - }
1.740 - else
1.741 - s->status = HCRC_STATE;
1.742 - }
1.743 - if (s->status == HCRC_STATE) {
1.744 - if (s->gzhead->hcrc) {
1.745 - if (s->pending + 2 > s->pending_buf_size)
1.746 - flush_pending(strm);
1.747 - if (s->pending + 2 <= s->pending_buf_size) {
1.748 - put_byte(s, (Byte)(strm->adler & 0xff));
1.749 - put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
1.750 - strm->adler = crc32(0L, Z_NULL, 0);
1.751 - s->status = BUSY_STATE;
1.752 - }
1.753 - }
1.754 - else
1.755 - s->status = BUSY_STATE;
1.756 - }
1.757 -#endif
1.758 -
1.759 - /* Flush as much pending output as possible */
1.760 - if (s->pending != 0) {
1.761 - flush_pending(strm);
1.762 - if (strm->avail_out == 0) {
1.763 - /* Since avail_out is 0, deflate will be called again with
1.764 - * more output space, but possibly with both pending and
1.765 - * avail_in equal to zero. There won't be anything to do,
1.766 - * but this is not an error situation so make sure we
1.767 - * return OK instead of BUF_ERROR at next call of deflate:
1.768 - */
1.769 - s->last_flush = -1;
1.770 - return Z_OK;
1.771 - }
1.772 -
1.773 - /* Make sure there is something to do and avoid duplicate consecutive
1.774 - * flushes. For repeated and useless calls with Z_FINISH, we keep
1.775 - * returning Z_STREAM_END instead of Z_BUF_ERROR.
1.776 - */
1.777 - } else if (strm->avail_in == 0 && flush <= old_flush &&
1.778 - flush != Z_FINISH) {
1.779 - ERR_RETURN(strm, Z_BUF_ERROR);
1.780 - }
1.781 -
1.782 - /* User must not provide more input after the first FINISH: */
1.783 - if (s->status == FINISH_STATE && strm->avail_in != 0) {
1.784 - ERR_RETURN(strm, Z_BUF_ERROR);
1.785 - }
1.786 -
1.787 - /* Start a new block or continue the current one.
1.788 - */
1.789 - if (strm->avail_in != 0 || s->lookahead != 0 ||
1.790 - (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
1.791 - block_state bstate;
1.792 -
1.793 - bstate = (*(configuration_table[s->level].func))(s, flush);
1.794 -
1.795 - if (bstate == finish_started || bstate == finish_done) {
1.796 - s->status = FINISH_STATE;
1.797 - }
1.798 - if (bstate == need_more || bstate == finish_started) {
1.799 - if (strm->avail_out == 0) {
1.800 - s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
1.801 - }
1.802 - return Z_OK;
1.803 - /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
1.804 - * of deflate should use the same flush parameter to make sure
1.805 - * that the flush is complete. So we don't have to output an
1.806 - * empty block here, this will be done at next call. This also
1.807 - * ensures that for a very small output buffer, we emit at most
1.808 - * one empty block.
1.809 - */
1.810 - }
1.811 - if (bstate == block_done) {
1.812 - if (flush == Z_PARTIAL_FLUSH) {
1.813 - _tr_align(s);
1.814 - } else { /* FULL_FLUSH or SYNC_FLUSH */
1.815 - _tr_stored_block(s, (char*)0, 0L, 0);
1.816 - /* For a full flush, this empty block will be recognized
1.817 - * as a special marker by inflate_sync().
1.818 - */
1.819 - if (flush == Z_FULL_FLUSH) {
1.820 - CLEAR_HASH(s); /* forget history */
1.821 - }
1.822 - }
1.823 - flush_pending(strm);
1.824 - if (strm->avail_out == 0) {
1.825 - s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
1.826 - return Z_OK;
1.827 - }
1.828 - }
1.829 - }
1.830 - Assert(strm->avail_out > 0, "bug2");
1.831 -
1.832 - if (flush != Z_FINISH) return Z_OK;
1.833 - if (s->wrap <= 0) return Z_STREAM_END;
1.834 -
1.835 - /* Write the trailer */
1.836 -#ifdef GZIP
1.837 - if (s->wrap == 2) {
1.838 - put_byte(s, (Byte)(strm->adler & 0xff));
1.839 - put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
1.840 - put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
1.841 - put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
1.842 - put_byte(s, (Byte)(strm->total_in & 0xff));
1.843 - put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
1.844 - put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
1.845 - put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
1.846 - }
1.847 - else
1.848 -#endif
1.849 - {
1.850 - putShortMSB(s, (uInt)(strm->adler >> 16));
1.851 - putShortMSB(s, (uInt)(strm->adler & 0xffff));
1.852 - }
1.853 - flush_pending(strm);
1.854 - /* If avail_out is zero, the application will call deflate again
1.855 - * to flush the rest.
1.856 - */
1.857 - if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
1.858 - return s->pending != 0 ? Z_OK : Z_STREAM_END;
1.859 -}
1.860 -
1.861 -/* ========================================================================= */
1.862 -int ZEXPORT deflateEnd (strm)
1.863 - z_streamp strm;
1.864 -{
1.865 - int status;
1.866 -
1.867 - if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1.868 -
1.869 - status = strm->state->status;
1.870 - if (status != INIT_STATE &&
1.871 - status != EXTRA_STATE &&
1.872 - status != NAME_STATE &&
1.873 - status != COMMENT_STATE &&
1.874 - status != HCRC_STATE &&
1.875 - status != BUSY_STATE &&
1.876 - status != FINISH_STATE) {
1.877 - return Z_STREAM_ERROR;
1.878 - }
1.879 -
1.880 - /* Deallocate in reverse order of allocations: */
1.881 - TRY_FREE(strm, strm->state->pending_buf);
1.882 - TRY_FREE(strm, strm->state->head);
1.883 - TRY_FREE(strm, strm->state->prev);
1.884 - TRY_FREE(strm, strm->state->window);
1.885 -
1.886 - ZFREE(strm, strm->state);
1.887 - strm->state = Z_NULL;
1.888 -
1.889 - return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
1.890 -}
1.891 -
1.892 -/* =========================================================================
1.893 - * Copy the source state to the destination state.
1.894 - * To simplify the source, this is not supported for 16-bit MSDOS (which
1.895 - * doesn't have enough memory anyway to duplicate compression states).
1.896 - */
1.897 -int ZEXPORT deflateCopy (dest, source)
1.898 - z_streamp dest;
1.899 - z_streamp source;
1.900 -{
1.901 -#ifdef MAXSEG_64K
1.902 - return Z_STREAM_ERROR;
1.903 -#else
1.904 - deflate_state *ds;
1.905 - deflate_state *ss;
1.906 - ushf *overlay;
1.907 -
1.908 -
1.909 - if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
1.910 - return Z_STREAM_ERROR;
1.911 - }
1.912 -
1.913 - ss = source->state;
1.914 -
1.915 - zmemcpy(dest, source, sizeof(z_stream));
1.916 -
1.917 - ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
1.918 - if (ds == Z_NULL) return Z_MEM_ERROR;
1.919 - dest->state = (struct internal_state FAR *) ds;
1.920 - zmemcpy(ds, ss, sizeof(deflate_state));
1.921 - ds->strm = dest;
1.922 -
1.923 - ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
1.924 - ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
1.925 - ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
1.926 - overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
1.927 - ds->pending_buf = (uchf *) overlay;
1.928 -
1.929 - if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
1.930 - ds->pending_buf == Z_NULL) {
1.931 - deflateEnd (dest);
1.932 - return Z_MEM_ERROR;
1.933 - }
1.934 - /* following zmemcpy do not work for 16-bit MSDOS */
1.935 - zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
1.936 - zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
1.937 - zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
1.938 - zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
1.939 -
1.940 - ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
1.941 - ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
1.942 - ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
1.943 -
1.944 - ds->l_desc.dyn_tree = ds->dyn_ltree;
1.945 - ds->d_desc.dyn_tree = ds->dyn_dtree;
1.946 - ds->bl_desc.dyn_tree = ds->bl_tree;
1.947 -
1.948 - return Z_OK;
1.949 -#endif /* MAXSEG_64K */
1.950 -}
1.951 -
1.952 -/* ===========================================================================
1.953 - * Read a new buffer from the current input stream, update the adler32
1.954 - * and total number of bytes read. All deflate() input goes through
1.955 - * this function so some applications may wish to modify it to avoid
1.956 - * allocating a large strm->next_in buffer and copying from it.
1.957 - * (See also flush_pending()).
1.958 - */
1.959 -local int read_buf(strm, buf, size)
1.960 - z_streamp strm;
1.961 - Bytef *buf;
1.962 - unsigned size;
1.963 -{
1.964 - unsigned len = strm->avail_in;
1.965 -
1.966 - if (len > size) len = size;
1.967 - if (len == 0) return 0;
1.968 -
1.969 - strm->avail_in -= len;
1.970 -
1.971 - if (strm->state->wrap == 1) {
1.972 - strm->adler = adler32(strm->adler, strm->next_in, len);
1.973 - }
1.974 -#ifdef GZIP
1.975 - else if (strm->state->wrap == 2) {
1.976 - strm->adler = crc32(strm->adler, strm->next_in, len);
1.977 - }
1.978 -#endif
1.979 - zmemcpy(buf, strm->next_in, len);
1.980 - strm->next_in += len;
1.981 - strm->total_in += len;
1.982 -
1.983 - return (int)len;
1.984 -}
1.985 -
1.986 -/* ===========================================================================
1.987 - * Initialize the "longest match" routines for a new zlib stream
1.988 - */
1.989 -local void lm_init (s)
1.990 - deflate_state *s;
1.991 -{
1.992 - s->window_size = (ulg)2L*s->w_size;
1.993 -
1.994 - CLEAR_HASH(s);
1.995 -
1.996 - /* Set the default configuration parameters:
1.997 - */
1.998 - s->max_lazy_match = configuration_table[s->level].max_lazy;
1.999 - s->good_match = configuration_table[s->level].good_length;
1.1000 - s->nice_match = configuration_table[s->level].nice_length;
1.1001 - s->max_chain_length = configuration_table[s->level].max_chain;
1.1002 -
1.1003 - s->strstart = 0;
1.1004 - s->block_start = 0L;
1.1005 - s->lookahead = 0;
1.1006 - s->match_length = s->prev_length = MIN_MATCH-1;
1.1007 - s->match_available = 0;
1.1008 - s->ins_h = 0;
1.1009 -#ifndef FASTEST
1.1010 -#ifdef ASMV
1.1011 - match_init(); /* initialize the asm code */
1.1012 -#endif
1.1013 -#endif
1.1014 -}
1.1015 -
1.1016 -#ifndef FASTEST
1.1017 -/* ===========================================================================
1.1018 - * Set match_start to the longest match starting at the given string and
1.1019 - * return its length. Matches shorter or equal to prev_length are discarded,
1.1020 - * in which case the result is equal to prev_length and match_start is
1.1021 - * garbage.
1.1022 - * IN assertions: cur_match is the head of the hash chain for the current
1.1023 - * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1.1024 - * OUT assertion: the match length is not greater than s->lookahead.
1.1025 - */
1.1026 -#ifndef ASMV
1.1027 -/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
1.1028 - * match.S. The code will be functionally equivalent.
1.1029 - */
1.1030 -local uInt longest_match(s, cur_match)
1.1031 - deflate_state *s;
1.1032 - IPos cur_match; /* current match */
1.1033 -{
1.1034 - unsigned chain_length = s->max_chain_length;/* max hash chain length */
1.1035 - register Bytef *scan = s->window + s->strstart; /* current string */
1.1036 - register Bytef *match; /* matched string */
1.1037 - register int len; /* length of current match */
1.1038 - int best_len = s->prev_length; /* best match length so far */
1.1039 - int nice_match = s->nice_match; /* stop if match long enough */
1.1040 - IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1.1041 - s->strstart - (IPos)MAX_DIST(s) : NIL;
1.1042 - /* Stop when cur_match becomes <= limit. To simplify the code,
1.1043 - * we prevent matches with the string of window index 0.
1.1044 - */
1.1045 - Posf *prev = s->prev;
1.1046 - uInt wmask = s->w_mask;
1.1047 -
1.1048 -#ifdef UNALIGNED_OK
1.1049 - /* Compare two bytes at a time. Note: this is not always beneficial.
1.1050 - * Try with and without -DUNALIGNED_OK to check.
1.1051 - */
1.1052 - register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1.1053 - register ush scan_start = *(ushf*)scan;
1.1054 - register ush scan_end = *(ushf*)(scan+best_len-1);
1.1055 -#else
1.1056 - register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1.1057 - register Byte scan_end1 = scan[best_len-1];
1.1058 - register Byte scan_end = scan[best_len];
1.1059 -#endif
1.1060 -
1.1061 - /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1.1062 - * It is easy to get rid of this optimization if necessary.
1.1063 - */
1.1064 - Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1.1065 -
1.1066 - /* Do not waste too much time if we already have a good match: */
1.1067 - if (s->prev_length >= s->good_match) {
1.1068 - chain_length >>= 2;
1.1069 - }
1.1070 - /* Do not look for matches beyond the end of the input. This is necessary
1.1071 - * to make deflate deterministic.
1.1072 - */
1.1073 - if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1.1074 -
1.1075 - Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1.1076 -
1.1077 - do {
1.1078 - Assert(cur_match < s->strstart, "no future");
1.1079 - match = s->window + cur_match;
1.1080 -
1.1081 - /* Skip to next match if the match length cannot increase
1.1082 - * or if the match length is less than 2. Note that the checks below
1.1083 - * for insufficient lookahead only occur occasionally for performance
1.1084 - * reasons. Therefore uninitialized memory will be accessed, and
1.1085 - * conditional jumps will be made that depend on those values.
1.1086 - * However the length of the match is limited to the lookahead, so
1.1087 - * the output of deflate is not affected by the uninitialized values.
1.1088 - */
1.1089 -#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1.1090 - /* This code assumes sizeof(unsigned short) == 2. Do not use
1.1091 - * UNALIGNED_OK if your compiler uses a different size.
1.1092 - */
1.1093 - if (*(ushf*)(match+best_len-1) != scan_end ||
1.1094 - *(ushf*)match != scan_start) continue;
1.1095 -
1.1096 - /* It is not necessary to compare scan[2] and match[2] since they are
1.1097 - * always equal when the other bytes match, given that the hash keys
1.1098 - * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1.1099 - * strstart+3, +5, ... up to strstart+257. We check for insufficient
1.1100 - * lookahead only every 4th comparison; the 128th check will be made
1.1101 - * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1.1102 - * necessary to put more guard bytes at the end of the window, or
1.1103 - * to check more often for insufficient lookahead.
1.1104 - */
1.1105 - Assert(scan[2] == match[2], "scan[2]?");
1.1106 - scan++, match++;
1.1107 - do {
1.1108 - } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1.1109 - *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1.1110 - *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1.1111 - *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1.1112 - scan < strend);
1.1113 - /* The funny "do {}" generates better code on most compilers */
1.1114 -
1.1115 - /* Here, scan <= window+strstart+257 */
1.1116 - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1.1117 - if (*scan == *match) scan++;
1.1118 -
1.1119 - len = (MAX_MATCH - 1) - (int)(strend-scan);
1.1120 - scan = strend - (MAX_MATCH-1);
1.1121 -
1.1122 -#else /* UNALIGNED_OK */
1.1123 -
1.1124 - if (match[best_len] != scan_end ||
1.1125 - match[best_len-1] != scan_end1 ||
1.1126 - *match != *scan ||
1.1127 - *++match != scan[1]) continue;
1.1128 -
1.1129 - /* The check at best_len-1 can be removed because it will be made
1.1130 - * again later. (This heuristic is not always a win.)
1.1131 - * It is not necessary to compare scan[2] and match[2] since they
1.1132 - * are always equal when the other bytes match, given that
1.1133 - * the hash keys are equal and that HASH_BITS >= 8.
1.1134 - */
1.1135 - scan += 2, match++;
1.1136 - Assert(*scan == *match, "match[2]?");
1.1137 -
1.1138 - /* We check for insufficient lookahead only every 8th comparison;
1.1139 - * the 256th check will be made at strstart+258.
1.1140 - */
1.1141 - do {
1.1142 - } while (*++scan == *++match && *++scan == *++match &&
1.1143 - *++scan == *++match && *++scan == *++match &&
1.1144 - *++scan == *++match && *++scan == *++match &&
1.1145 - *++scan == *++match && *++scan == *++match &&
1.1146 - scan < strend);
1.1147 -
1.1148 - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1.1149 -
1.1150 - len = MAX_MATCH - (int)(strend - scan);
1.1151 - scan = strend - MAX_MATCH;
1.1152 -
1.1153 -#endif /* UNALIGNED_OK */
1.1154 -
1.1155 - if (len > best_len) {
1.1156 - s->match_start = cur_match;
1.1157 - best_len = len;
1.1158 - if (len >= nice_match) break;
1.1159 -#ifdef UNALIGNED_OK
1.1160 - scan_end = *(ushf*)(scan+best_len-1);
1.1161 -#else
1.1162 - scan_end1 = scan[best_len-1];
1.1163 - scan_end = scan[best_len];
1.1164 -#endif
1.1165 - }
1.1166 - } while ((cur_match = prev[cur_match & wmask]) > limit
1.1167 - && --chain_length != 0);
1.1168 -
1.1169 - if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1.1170 - return s->lookahead;
1.1171 -}
1.1172 -#endif /* ASMV */
1.1173 -#endif /* FASTEST */
1.1174 -
1.1175 -/* ---------------------------------------------------------------------------
1.1176 - * Optimized version for level == 1 or strategy == Z_RLE only
1.1177 - */
1.1178 -local uInt longest_match_fast(s, cur_match)
1.1179 - deflate_state *s;
1.1180 - IPos cur_match; /* current match */
1.1181 -{
1.1182 - register Bytef *scan = s->window + s->strstart; /* current string */
1.1183 - register Bytef *match; /* matched string */
1.1184 - register int len; /* length of current match */
1.1185 - register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1.1186 -
1.1187 - /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1.1188 - * It is easy to get rid of this optimization if necessary.
1.1189 - */
1.1190 - Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1.1191 -
1.1192 - Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1.1193 -
1.1194 - Assert(cur_match < s->strstart, "no future");
1.1195 -
1.1196 - match = s->window + cur_match;
1.1197 -
1.1198 - /* Return failure if the match length is less than 2:
1.1199 - */
1.1200 - if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1.1201 -
1.1202 - /* The check at best_len-1 can be removed because it will be made
1.1203 - * again later. (This heuristic is not always a win.)
1.1204 - * It is not necessary to compare scan[2] and match[2] since they
1.1205 - * are always equal when the other bytes match, given that
1.1206 - * the hash keys are equal and that HASH_BITS >= 8.
1.1207 - */
1.1208 - scan += 2, match += 2;
1.1209 - Assert(*scan == *match, "match[2]?");
1.1210 -
1.1211 - /* We check for insufficient lookahead only every 8th comparison;
1.1212 - * the 256th check will be made at strstart+258.
1.1213 - */
1.1214 - do {
1.1215 - } while (*++scan == *++match && *++scan == *++match &&
1.1216 - *++scan == *++match && *++scan == *++match &&
1.1217 - *++scan == *++match && *++scan == *++match &&
1.1218 - *++scan == *++match && *++scan == *++match &&
1.1219 - scan < strend);
1.1220 -
1.1221 - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1.1222 -
1.1223 - len = MAX_MATCH - (int)(strend - scan);
1.1224 -
1.1225 - if (len < MIN_MATCH) return MIN_MATCH - 1;
1.1226 -
1.1227 - s->match_start = cur_match;
1.1228 - return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1.1229 -}
1.1230 -
1.1231 -#ifdef DEBUG
1.1232 -/* ===========================================================================
1.1233 - * Check that the match at match_start is indeed a match.
1.1234 - */
1.1235 -local void check_match(s, start, match, length)
1.1236 - deflate_state *s;
1.1237 - IPos start, match;
1.1238 - int length;
1.1239 -{
1.1240 - /* check that the match is indeed a match */
1.1241 - if (zmemcmp(s->window + match,
1.1242 - s->window + start, length) != EQUAL) {
1.1243 - fprintf(stderr, " start %u, match %u, length %d\n",
1.1244 - start, match, length);
1.1245 - do {
1.1246 - fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
1.1247 - } while (--length != 0);
1.1248 - z_error("invalid match");
1.1249 - }
1.1250 - if (z_verbose > 1) {
1.1251 - fprintf(stderr,"\\[%d,%d]", start-match, length);
1.1252 - do { putc(s->window[start++], stderr); } while (--length != 0);
1.1253 - }
1.1254 -}
1.1255 -#else
1.1256 -# define check_match(s, start, match, length)
1.1257 -#endif /* DEBUG */
1.1258 -
1.1259 -/* ===========================================================================
1.1260 - * Fill the window when the lookahead becomes insufficient.
1.1261 - * Updates strstart and lookahead.
1.1262 - *
1.1263 - * IN assertion: lookahead < MIN_LOOKAHEAD
1.1264 - * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
1.1265 - * At least one byte has been read, or avail_in == 0; reads are
1.1266 - * performed for at least two bytes (required for the zip translate_eol
1.1267 - * option -- not supported here).
1.1268 - */
1.1269 -local void fill_window(s)
1.1270 - deflate_state *s;
1.1271 -{
1.1272 - register unsigned n, m;
1.1273 - register Posf *p;
1.1274 - unsigned more; /* Amount of free space at the end of the window. */
1.1275 - uInt wsize = s->w_size;
1.1276 -
1.1277 - do {
1.1278 - more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
1.1279 -
1.1280 - /* Deal with !@#$% 64K limit: */
1.1281 - if (sizeof(int) <= 2) {
1.1282 - if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
1.1283 - more = wsize;
1.1284 -
1.1285 - } else if (more == (unsigned)(-1)) {
1.1286 - /* Very unlikely, but possible on 16 bit machine if
1.1287 - * strstart == 0 && lookahead == 1 (input done a byte at time)
1.1288 - */
1.1289 - more--;
1.1290 - }
1.1291 - }
1.1292 -
1.1293 - /* If the window is almost full and there is insufficient lookahead,
1.1294 - * move the upper half to the lower one to make room in the upper half.
1.1295 - */
1.1296 - if (s->strstart >= wsize+MAX_DIST(s)) {
1.1297 -
1.1298 - zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
1.1299 - s->match_start -= wsize;
1.1300 - s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
1.1301 - s->block_start -= (long) wsize;
1.1302 -
1.1303 - /* Slide the hash table (could be avoided with 32 bit values
1.1304 - at the expense of memory usage). We slide even when level == 0
1.1305 - to keep the hash table consistent if we switch back to level > 0
1.1306 - later. (Using level 0 permanently is not an optimal usage of
1.1307 - zlib, so we don't care about this pathological case.)
1.1308 - */
1.1309 - /* %%% avoid this when Z_RLE */
1.1310 - n = s->hash_size;
1.1311 - p = &s->head[n];
1.1312 - do {
1.1313 - m = *--p;
1.1314 - *p = (Pos)(m >= wsize ? m-wsize : NIL);
1.1315 - } while (--n);
1.1316 -
1.1317 - n = wsize;
1.1318 -#ifndef FASTEST
1.1319 - p = &s->prev[n];
1.1320 - do {
1.1321 - m = *--p;
1.1322 - *p = (Pos)(m >= wsize ? m-wsize : NIL);
1.1323 - /* If n is not on any hash chain, prev[n] is garbage but
1.1324 - * its value will never be used.
1.1325 - */
1.1326 - } while (--n);
1.1327 -#endif
1.1328 - more += wsize;
1.1329 - }
1.1330 - if (s->strm->avail_in == 0) return;
1.1331 -
1.1332 - /* If there was no sliding:
1.1333 - * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
1.1334 - * more == window_size - lookahead - strstart
1.1335 - * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
1.1336 - * => more >= window_size - 2*WSIZE + 2
1.1337 - * In the BIG_MEM or MMAP case (not yet supported),
1.1338 - * window_size == input_size + MIN_LOOKAHEAD &&
1.1339 - * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
1.1340 - * Otherwise, window_size == 2*WSIZE so more >= 2.
1.1341 - * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
1.1342 - */
1.1343 - Assert(more >= 2, "more < 2");
1.1344 -
1.1345 - n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
1.1346 - s->lookahead += n;
1.1347 -
1.1348 - /* Initialize the hash value now that we have some input: */
1.1349 - if (s->lookahead >= MIN_MATCH) {
1.1350 - s->ins_h = s->window[s->strstart];
1.1351 - UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1.1352 -#if MIN_MATCH != 3
1.1353 - Call UPDATE_HASH() MIN_MATCH-3 more times
1.1354 -#endif
1.1355 - }
1.1356 - /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
1.1357 - * but this is not important since only literal bytes will be emitted.
1.1358 - */
1.1359 -
1.1360 - } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
1.1361 -}
1.1362 -
1.1363 -/* ===========================================================================
1.1364 - * Flush the current block, with given end-of-file flag.
1.1365 - * IN assertion: strstart is set to the end of the current match.
1.1366 - */
1.1367 -#define FLUSH_BLOCK_ONLY(s, eof) { \
1.1368 - _tr_flush_block(s, (s->block_start >= 0L ? \
1.1369 - (charf *)&s->window[(unsigned)s->block_start] : \
1.1370 - (charf *)Z_NULL), \
1.1371 - (ulg)((long)s->strstart - s->block_start), \
1.1372 - (eof)); \
1.1373 - s->block_start = s->strstart; \
1.1374 - flush_pending(s->strm); \
1.1375 - Tracev((stderr,"[FLUSH]")); \
1.1376 -}
1.1377 -
1.1378 -/* Same but force premature exit if necessary. */
1.1379 -#define FLUSH_BLOCK(s, eof) { \
1.1380 - FLUSH_BLOCK_ONLY(s, eof); \
1.1381 - if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
1.1382 -}
1.1383 -
1.1384 -/* ===========================================================================
1.1385 - * Copy without compression as much as possible from the input stream, return
1.1386 - * the current block state.
1.1387 - * This function does not insert new strings in the dictionary since
1.1388 - * uncompressible data is probably not useful. This function is used
1.1389 - * only for the level=0 compression option.
1.1390 - * NOTE: this function should be optimized to avoid extra copying from
1.1391 - * window to pending_buf.
1.1392 - */
1.1393 -local block_state deflate_stored(s, flush)
1.1394 - deflate_state *s;
1.1395 - int flush;
1.1396 -{
1.1397 - /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
1.1398 - * to pending_buf_size, and each stored block has a 5 byte header:
1.1399 - */
1.1400 - ulg max_block_size = 0xffff;
1.1401 - ulg max_start;
1.1402 -
1.1403 - if (max_block_size > s->pending_buf_size - 5) {
1.1404 - max_block_size = s->pending_buf_size - 5;
1.1405 - }
1.1406 -
1.1407 - /* Copy as much as possible from input to output: */
1.1408 - for (;;) {
1.1409 - /* Fill the window as much as possible: */
1.1410 - if (s->lookahead <= 1) {
1.1411 -
1.1412 - Assert(s->strstart < s->w_size+MAX_DIST(s) ||
1.1413 - s->block_start >= (long)s->w_size, "slide too late");
1.1414 -
1.1415 - fill_window(s);
1.1416 - if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
1.1417 -
1.1418 - if (s->lookahead == 0) break; /* flush the current block */
1.1419 - }
1.1420 - Assert(s->block_start >= 0L, "block gone");
1.1421 -
1.1422 - s->strstart += s->lookahead;
1.1423 - s->lookahead = 0;
1.1424 -
1.1425 - /* Emit a stored block if pending_buf will be full: */
1.1426 - max_start = s->block_start + max_block_size;
1.1427 - if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
1.1428 - /* strstart == 0 is possible when wraparound on 16-bit machine */
1.1429 - s->lookahead = (uInt)(s->strstart - max_start);
1.1430 - s->strstart = (uInt)max_start;
1.1431 - FLUSH_BLOCK(s, 0);
1.1432 - }
1.1433 - /* Flush if we may have to slide, otherwise block_start may become
1.1434 - * negative and the data will be gone:
1.1435 - */
1.1436 - if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
1.1437 - FLUSH_BLOCK(s, 0);
1.1438 - }
1.1439 - }
1.1440 - FLUSH_BLOCK(s, flush == Z_FINISH);
1.1441 - return flush == Z_FINISH ? finish_done : block_done;
1.1442 -}
1.1443 -
1.1444 -/* ===========================================================================
1.1445 - * Compress as much as possible from the input stream, return the current
1.1446 - * block state.
1.1447 - * This function does not perform lazy evaluation of matches and inserts
1.1448 - * new strings in the dictionary only for unmatched strings or for short
1.1449 - * matches. It is used only for the fast compression options.
1.1450 - */
1.1451 -local block_state deflate_fast(s, flush)
1.1452 - deflate_state *s;
1.1453 - int flush;
1.1454 -{
1.1455 - IPos hash_head = NIL; /* head of the hash chain */
1.1456 - int bflush; /* set if current block must be flushed */
1.1457 -
1.1458 - for (;;) {
1.1459 - /* Make sure that we always have enough lookahead, except
1.1460 - * at the end of the input file. We need MAX_MATCH bytes
1.1461 - * for the next match, plus MIN_MATCH bytes to insert the
1.1462 - * string following the next match.
1.1463 - */
1.1464 - if (s->lookahead < MIN_LOOKAHEAD) {
1.1465 - fill_window(s);
1.1466 - if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1.1467 - return need_more;
1.1468 - }
1.1469 - if (s->lookahead == 0) break; /* flush the current block */
1.1470 - }
1.1471 -
1.1472 - /* Insert the string window[strstart .. strstart+2] in the
1.1473 - * dictionary, and set hash_head to the head of the hash chain:
1.1474 - */
1.1475 - if (s->lookahead >= MIN_MATCH) {
1.1476 - INSERT_STRING(s, s->strstart, hash_head);
1.1477 - }
1.1478 -
1.1479 - /* Find the longest match, discarding those <= prev_length.
1.1480 - * At this point we have always match_length < MIN_MATCH
1.1481 - */
1.1482 - if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1.1483 - /* To simplify the code, we prevent matches with the string
1.1484 - * of window index 0 (in particular we have to avoid a match
1.1485 - * of the string with itself at the start of the input file).
1.1486 - */
1.1487 -#ifdef FASTEST
1.1488 - if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
1.1489 - (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
1.1490 - s->match_length = longest_match_fast (s, hash_head);
1.1491 - }
1.1492 -#else
1.1493 - if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1.1494 - s->match_length = longest_match (s, hash_head);
1.1495 - } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1.1496 - s->match_length = longest_match_fast (s, hash_head);
1.1497 - }
1.1498 -#endif
1.1499 - /* longest_match() or longest_match_fast() sets match_start */
1.1500 - }
1.1501 - if (s->match_length >= MIN_MATCH) {
1.1502 - check_match(s, s->strstart, s->match_start, s->match_length);
1.1503 -
1.1504 - _tr_tally_dist(s, s->strstart - s->match_start,
1.1505 - s->match_length - MIN_MATCH, bflush);
1.1506 -
1.1507 - s->lookahead -= s->match_length;
1.1508 -
1.1509 - /* Insert new strings in the hash table only if the match length
1.1510 - * is not too large. This saves time but degrades compression.
1.1511 - */
1.1512 -#ifndef FASTEST
1.1513 - if (s->match_length <= s->max_insert_length &&
1.1514 - s->lookahead >= MIN_MATCH) {
1.1515 - s->match_length--; /* string at strstart already in table */
1.1516 - do {
1.1517 - s->strstart++;
1.1518 - INSERT_STRING(s, s->strstart, hash_head);
1.1519 - /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1.1520 - * always MIN_MATCH bytes ahead.
1.1521 - */
1.1522 - } while (--s->match_length != 0);
1.1523 - s->strstart++;
1.1524 - } else
1.1525 -#endif
1.1526 - {
1.1527 - s->strstart += s->match_length;
1.1528 - s->match_length = 0;
1.1529 - s->ins_h = s->window[s->strstart];
1.1530 - UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1.1531 -#if MIN_MATCH != 3
1.1532 - Call UPDATE_HASH() MIN_MATCH-3 more times
1.1533 -#endif
1.1534 - /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1.1535 - * matter since it will be recomputed at next deflate call.
1.1536 - */
1.1537 - }
1.1538 - } else {
1.1539 - /* No match, output a literal byte */
1.1540 - Tracevv((stderr,"%c", s->window[s->strstart]));
1.1541 - _tr_tally_lit (s, s->window[s->strstart], bflush);
1.1542 - s->lookahead--;
1.1543 - s->strstart++;
1.1544 - }
1.1545 - if (bflush) FLUSH_BLOCK(s, 0);
1.1546 - }
1.1547 - FLUSH_BLOCK(s, flush == Z_FINISH);
1.1548 - return flush == Z_FINISH ? finish_done : block_done;
1.1549 -}
1.1550 -
1.1551 -#ifndef FASTEST
1.1552 -/* ===========================================================================
1.1553 - * Same as above, but achieves better compression. We use a lazy
1.1554 - * evaluation for matches: a match is finally adopted only if there is
1.1555 - * no better match at the next window position.
1.1556 - */
1.1557 -local block_state deflate_slow(s, flush)
1.1558 - deflate_state *s;
1.1559 - int flush;
1.1560 -{
1.1561 - IPos hash_head = NIL; /* head of hash chain */
1.1562 - int bflush; /* set if current block must be flushed */
1.1563 -
1.1564 - /* Process the input block. */
1.1565 - for (;;) {
1.1566 - /* Make sure that we always have enough lookahead, except
1.1567 - * at the end of the input file. We need MAX_MATCH bytes
1.1568 - * for the next match, plus MIN_MATCH bytes to insert the
1.1569 - * string following the next match.
1.1570 - */
1.1571 - if (s->lookahead < MIN_LOOKAHEAD) {
1.1572 - fill_window(s);
1.1573 - if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1.1574 - return need_more;
1.1575 - }
1.1576 - if (s->lookahead == 0) break; /* flush the current block */
1.1577 - }
1.1578 -
1.1579 - /* Insert the string window[strstart .. strstart+2] in the
1.1580 - * dictionary, and set hash_head to the head of the hash chain:
1.1581 - */
1.1582 - if (s->lookahead >= MIN_MATCH) {
1.1583 - INSERT_STRING(s, s->strstart, hash_head);
1.1584 - }
1.1585 -
1.1586 - /* Find the longest match, discarding those <= prev_length.
1.1587 - */
1.1588 - s->prev_length = s->match_length, s->prev_match = s->match_start;
1.1589 - s->match_length = MIN_MATCH-1;
1.1590 -
1.1591 - if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1.1592 - s->strstart - hash_head <= MAX_DIST(s)) {
1.1593 - /* To simplify the code, we prevent matches with the string
1.1594 - * of window index 0 (in particular we have to avoid a match
1.1595 - * of the string with itself at the start of the input file).
1.1596 - */
1.1597 - if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1.1598 - s->match_length = longest_match (s, hash_head);
1.1599 - } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1.1600 - s->match_length = longest_match_fast (s, hash_head);
1.1601 - }
1.1602 - /* longest_match() or longest_match_fast() sets match_start */
1.1603 -
1.1604 - if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1.1605 -#if TOO_FAR <= 32767
1.1606 - || (s->match_length == MIN_MATCH &&
1.1607 - s->strstart - s->match_start > TOO_FAR)
1.1608 -#endif
1.1609 - )) {
1.1610 -
1.1611 - /* If prev_match is also MIN_MATCH, match_start is garbage
1.1612 - * but we will ignore the current match anyway.
1.1613 - */
1.1614 - s->match_length = MIN_MATCH-1;
1.1615 - }
1.1616 - }
1.1617 - /* If there was a match at the previous step and the current
1.1618 - * match is not better, output the previous match:
1.1619 - */
1.1620 - if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1.1621 - uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1.1622 - /* Do not insert strings in hash table beyond this. */
1.1623 -
1.1624 - check_match(s, s->strstart-1, s->prev_match, s->prev_length);
1.1625 -
1.1626 - _tr_tally_dist(s, s->strstart -1 - s->prev_match,
1.1627 - s->prev_length - MIN_MATCH, bflush);
1.1628 -
1.1629 - /* Insert in hash table all strings up to the end of the match.
1.1630 - * strstart-1 and strstart are already inserted. If there is not
1.1631 - * enough lookahead, the last two strings are not inserted in
1.1632 - * the hash table.
1.1633 - */
1.1634 - s->lookahead -= s->prev_length-1;
1.1635 - s->prev_length -= 2;
1.1636 - do {
1.1637 - if (++s->strstart <= max_insert) {
1.1638 - INSERT_STRING(s, s->strstart, hash_head);
1.1639 - }
1.1640 - } while (--s->prev_length != 0);
1.1641 - s->match_available = 0;
1.1642 - s->match_length = MIN_MATCH-1;
1.1643 - s->strstart++;
1.1644 -
1.1645 - if (bflush) FLUSH_BLOCK(s, 0);
1.1646 -
1.1647 - } else if (s->match_available) {
1.1648 - /* If there was no match at the previous position, output a
1.1649 - * single literal. If there was a match but the current match
1.1650 - * is longer, truncate the previous match to a single literal.
1.1651 - */
1.1652 - Tracevv((stderr,"%c", s->window[s->strstart-1]));
1.1653 - _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1.1654 - if (bflush) {
1.1655 - FLUSH_BLOCK_ONLY(s, 0);
1.1656 - }
1.1657 - s->strstart++;
1.1658 - s->lookahead--;
1.1659 - if (s->strm->avail_out == 0) return need_more;
1.1660 - } else {
1.1661 - /* There is no previous match to compare with, wait for
1.1662 - * the next step to decide.
1.1663 - */
1.1664 - s->match_available = 1;
1.1665 - s->strstart++;
1.1666 - s->lookahead--;
1.1667 - }
1.1668 - }
1.1669 - Assert (flush != Z_NO_FLUSH, "no flush?");
1.1670 - if (s->match_available) {
1.1671 - Tracevv((stderr,"%c", s->window[s->strstart-1]));
1.1672 - _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1.1673 - s->match_available = 0;
1.1674 - }
1.1675 - FLUSH_BLOCK(s, flush == Z_FINISH);
1.1676 - return flush == Z_FINISH ? finish_done : block_done;
1.1677 -}
1.1678 -#endif /* FASTEST */
1.1679 -
1.1680 -#if 0
1.1681 -/* ===========================================================================
1.1682 - * For Z_RLE, simply look for runs of bytes, generate matches only of distance
1.1683 - * one. Do not maintain a hash table. (It will be regenerated if this run of
1.1684 - * deflate switches away from Z_RLE.)
1.1685 - */
1.1686 -local block_state deflate_rle(s, flush)
1.1687 - deflate_state *s;
1.1688 - int flush;
1.1689 -{
1.1690 - int bflush; /* set if current block must be flushed */
1.1691 - uInt run; /* length of run */
1.1692 - uInt max; /* maximum length of run */
1.1693 - uInt prev; /* byte at distance one to match */
1.1694 - Bytef *scan; /* scan for end of run */
1.1695 -
1.1696 - for (;;) {
1.1697 - /* Make sure that we always have enough lookahead, except
1.1698 - * at the end of the input file. We need MAX_MATCH bytes
1.1699 - * for the longest encodable run.
1.1700 - */
1.1701 - if (s->lookahead < MAX_MATCH) {
1.1702 - fill_window(s);
1.1703 - if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
1.1704 - return need_more;
1.1705 - }
1.1706 - if (s->lookahead == 0) break; /* flush the current block */
1.1707 - }
1.1708 -
1.1709 - /* See how many times the previous byte repeats */
1.1710 - run = 0;
1.1711 - if (s->strstart > 0) { /* if there is a previous byte, that is */
1.1712 - max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
1.1713 - scan = s->window + s->strstart - 1;
1.1714 - prev = *scan++;
1.1715 - do {
1.1716 - if (*scan++ != prev)
1.1717 - break;
1.1718 - } while (++run < max);
1.1719 - }
1.1720 -
1.1721 - /* Emit match if have run of MIN_MATCH or longer, else emit literal */
1.1722 - if (run >= MIN_MATCH) {
1.1723 - check_match(s, s->strstart, s->strstart - 1, run);
1.1724 - _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
1.1725 - s->lookahead -= run;
1.1726 - s->strstart += run;
1.1727 - } else {
1.1728 - /* No match, output a literal byte */
1.1729 - Tracevv((stderr,"%c", s->window[s->strstart]));
1.1730 - _tr_tally_lit (s, s->window[s->strstart], bflush);
1.1731 - s->lookahead--;
1.1732 - s->strstart++;
1.1733 - }
1.1734 - if (bflush) FLUSH_BLOCK(s, 0);
1.1735 - }
1.1736 - FLUSH_BLOCK(s, flush == Z_FINISH);
1.1737 - return flush == Z_FINISH ? finish_done : block_done;
1.1738 -}
1.1739 -#endif
