diff options
Diffstat (limited to 'libs/zlib/src/deflate.c')
| -rw-r--r-- | libs/zlib/src/deflate.c | 4428 |
1 files changed, 2217 insertions, 2211 deletions
diff --git a/libs/zlib/src/deflate.c b/libs/zlib/src/deflate.c index 799fb93cc0..18a90bb83d 100644 --- a/libs/zlib/src/deflate.c +++ b/libs/zlib/src/deflate.c @@ -1,2211 +1,2217 @@ -/* deflate.c -- compress data using the deflation algorithm - * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler - * For conditions of distribution and use, see copyright notice in zlib.h - */ - -/* - * ALGORITHM - * - * The "deflation" process depends on being able to identify portions - * of the input text which are identical to earlier input (within a - * sliding window trailing behind the input currently being processed). - * - * The most straightforward technique turns out to be the fastest for - * most input files: try all possible matches and select the longest. - * The key feature of this algorithm is that insertions into the string - * dictionary are very simple and thus fast, and deletions are avoided - * completely. Insertions are performed at each input character, whereas - * string matches are performed only when the previous match ends. So it - * is preferable to spend more time in matches to allow very fast string - * insertions and avoid deletions. The matching algorithm for small - * strings is inspired from that of Rabin & Karp. A brute force approach - * is used to find longer strings when a small match has been found. - * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze - * (by Leonid Broukhis). - * A previous version of this file used a more sophisticated algorithm - * (by Fiala and Greene) which is guaranteed to run in linear amortized - * time, but has a larger average cost, uses more memory and is patented. - * However the F&G algorithm may be faster for some highly redundant - * files if the parameter max_chain_length (described below) is too large. - * - * ACKNOWLEDGEMENTS - * - * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and - * I found it in 'freeze' written by Leonid Broukhis. - * Thanks to many people for bug reports and testing. - * - * REFERENCES - * - * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". - * Available in http://tools.ietf.org/html/rfc1951 - * - * A description of the Rabin and Karp algorithm is given in the book - * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. - * - * Fiala,E.R., and Greene,D.H. - * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 - * - */ - -/* @(#) $Id$ */ - -#include "deflate.h" - -const char deflate_copyright[] = - " deflate 1.2.12 Copyright 1995-2022 Jean-loup Gailly and Mark Adler "; -/* - If you use the zlib library in a product, an acknowledgment is welcome - in the documentation of your product. If for some reason you cannot - include such an acknowledgment, I would appreciate that you keep this - copyright string in the executable of your product. - */ - -/* =========================================================================== - * Function prototypes. - */ -typedef enum { - need_more, /* block not completed, need more input or more output */ - block_done, /* block flush performed */ - finish_started, /* finish started, need only more output at next deflate */ - finish_done /* finish done, accept no more input or output */ -} block_state; - -typedef block_state (*compress_func) OF((deflate_state *s, int flush)); -/* Compression function. Returns the block state after the call. */ - -local int deflateStateCheck OF((z_streamp strm)); -local void slide_hash OF((deflate_state *s)); -local void fill_window OF((deflate_state *s)); -local block_state deflate_stored OF((deflate_state *s, int flush)); -local block_state deflate_fast OF((deflate_state *s, int flush)); -#ifndef FASTEST -local block_state deflate_slow OF((deflate_state *s, int flush)); -#endif -local block_state deflate_rle OF((deflate_state *s, int flush)); -local block_state deflate_huff OF((deflate_state *s, int flush)); -local void lm_init OF((deflate_state *s)); -local void putShortMSB OF((deflate_state *s, uInt b)); -local void flush_pending OF((z_streamp strm)); -local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); -#ifdef ASMV -# pragma message("Assembler code may have bugs -- use at your own risk") - void match_init OF((void)); /* asm code initialization */ - uInt longest_match OF((deflate_state *s, IPos cur_match)); -#else -local uInt longest_match OF((deflate_state *s, IPos cur_match)); -#endif - -#ifdef ZLIB_DEBUG -local void check_match OF((deflate_state *s, IPos start, IPos match, - int length)); -#endif - -/* =========================================================================== - * Local data - */ - -#define NIL 0 -/* Tail of hash chains */ - -#ifndef TOO_FAR -# define TOO_FAR 4096 -#endif -/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ - -/* Values for max_lazy_match, good_match and max_chain_length, depending on - * the desired pack level (0..9). The values given below have been tuned to - * exclude worst case performance for pathological files. Better values may be - * found for specific files. - */ -typedef struct config_s { - ush good_length; /* reduce lazy search above this match length */ - ush max_lazy; /* do not perform lazy search above this match length */ - ush nice_length; /* quit search above this match length */ - ush max_chain; - compress_func func; -} config; - -#ifdef FASTEST -local const config configuration_table[2] = { -/* good lazy nice chain */ -/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ -/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ -#else -local const config configuration_table[10] = { -/* good lazy nice chain */ -/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ -/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ -/* 2 */ {4, 5, 16, 8, deflate_fast}, -/* 3 */ {4, 6, 32, 32, deflate_fast}, - -/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ -/* 5 */ {8, 16, 32, 32, deflate_slow}, -/* 6 */ {8, 16, 128, 128, deflate_slow}, -/* 7 */ {8, 32, 128, 256, deflate_slow}, -/* 8 */ {32, 128, 258, 1024, deflate_slow}, -/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ -#endif - -/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 - * For deflate_fast() (levels <= 3) good is ignored and lazy has a different - * meaning. - */ - -/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */ -#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0)) - -/* =========================================================================== - * Update a hash value with the given input byte - * IN assertion: all calls to UPDATE_HASH are made with consecutive input - * characters, so that a running hash key can be computed from the previous - * key instead of complete recalculation each time. - */ -#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) - - -/* =========================================================================== - * Insert string str in the dictionary and set match_head to the previous head - * of the hash chain (the most recent string with same hash key). Return - * the previous length of the hash chain. - * If this file is compiled with -DFASTEST, the compression level is forced - * to 1, and no hash chains are maintained. - * IN assertion: all calls to INSERT_STRING are made with consecutive input - * characters and the first MIN_MATCH bytes of str are valid (except for - * the last MIN_MATCH-1 bytes of the input file). - */ -#ifdef FASTEST -#define INSERT_STRING(s, str, match_head) \ - (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ - match_head = s->head[s->ins_h], \ - s->head[s->ins_h] = (Pos)(str)) -#else -#define INSERT_STRING(s, str, match_head) \ - (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ - match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ - s->head[s->ins_h] = (Pos)(str)) -#endif - -/* =========================================================================== - * Initialize the hash table (avoiding 64K overflow for 16 bit systems). - * prev[] will be initialized on the fly. - */ -#define CLEAR_HASH(s) \ - do { \ - s->head[s->hash_size-1] = NIL; \ - zmemzero((Bytef *)s->head, \ - (unsigned)(s->hash_size-1)*sizeof(*s->head)); \ - } while (0) - -/* =========================================================================== - * Slide the hash table when sliding the window down (could be avoided with 32 - * bit values at the expense of memory usage). We slide even when level == 0 to - * keep the hash table consistent if we switch back to level > 0 later. - */ -local void slide_hash(s) - deflate_state *s; -{ - unsigned n, m; - Posf *p; - uInt wsize = s->w_size; - - n = s->hash_size; - p = &s->head[n]; - do { - m = *--p; - *p = (Pos)(m >= wsize ? m - wsize : NIL); - } while (--n); - n = wsize; -#ifndef FASTEST - p = &s->prev[n]; - do { - m = *--p; - *p = (Pos)(m >= wsize ? m - wsize : NIL); - /* If n is not on any hash chain, prev[n] is garbage but - * its value will never be used. - */ - } while (--n); -#endif -} - -/* ========================================================================= */ -int ZEXPORT deflateInit_(strm, level, version, stream_size) - z_streamp strm; - int level; - const char *version; - int stream_size; -{ - return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, - Z_DEFAULT_STRATEGY, version, stream_size); - /* To do: ignore strm->next_in if we use it as window */ -} - -/* ========================================================================= */ -int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, - version, stream_size) - z_streamp strm; - int level; - int method; - int windowBits; - int memLevel; - int strategy; - const char *version; - int stream_size; -{ - deflate_state *s; - int wrap = 1; - static const char my_version[] = ZLIB_VERSION; - - if (version == Z_NULL || version[0] != my_version[0] || - stream_size != sizeof(z_stream)) { - return Z_VERSION_ERROR; - } - if (strm == Z_NULL) return Z_STREAM_ERROR; - - strm->msg = Z_NULL; - if (strm->zalloc == (alloc_func)0) { -#ifdef Z_SOLO - return Z_STREAM_ERROR; -#else - strm->zalloc = zcalloc; - strm->opaque = (voidpf)0; -#endif - } - if (strm->zfree == (free_func)0) -#ifdef Z_SOLO - return Z_STREAM_ERROR; -#else - strm->zfree = zcfree; -#endif - -#ifdef FASTEST - if (level != 0) level = 1; -#else - if (level == Z_DEFAULT_COMPRESSION) level = 6; -#endif - - if (windowBits < 0) { /* suppress zlib wrapper */ - wrap = 0; - windowBits = -windowBits; - } -#ifdef GZIP - else if (windowBits > 15) { - wrap = 2; /* write gzip wrapper instead */ - windowBits -= 16; - } -#endif - if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || - windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || - strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) { - return Z_STREAM_ERROR; - } - if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ - s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); - if (s == Z_NULL) return Z_MEM_ERROR; - strm->state = (struct internal_state FAR *)s; - s->strm = strm; - s->status = INIT_STATE; /* to pass state test in deflateReset() */ - - s->wrap = wrap; - s->gzhead = Z_NULL; - s->w_bits = (uInt)windowBits; - s->w_size = 1 << s->w_bits; - s->w_mask = s->w_size - 1; - - s->hash_bits = (uInt)memLevel + 7; - s->hash_size = 1 << s->hash_bits; - s->hash_mask = s->hash_size - 1; - s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); - - s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); - s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); - s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); - - s->high_water = 0; /* nothing written to s->window yet */ - - s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ - - /* We overlay pending_buf and sym_buf. This works since the average size - * for length/distance pairs over any compressed block is assured to be 31 - * bits or less. - * - * Analysis: The longest fixed codes are a length code of 8 bits plus 5 - * extra bits, for lengths 131 to 257. The longest fixed distance codes are - * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest - * possible fixed-codes length/distance pair is then 31 bits total. - * - * sym_buf starts one-fourth of the way into pending_buf. So there are - * three bytes in sym_buf for every four bytes in pending_buf. Each symbol - * in sym_buf is three bytes -- two for the distance and one for the - * literal/length. As each symbol is consumed, the pointer to the next - * sym_buf value to read moves forward three bytes. From that symbol, up to - * 31 bits are written to pending_buf. The closest the written pending_buf - * bits gets to the next sym_buf symbol to read is just before the last - * code is written. At that time, 31*(n-2) bits have been written, just - * after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at - * 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1 - * symbols are written.) The closest the writing gets to what is unread is - * then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and - * can range from 128 to 32768. - * - * Therefore, at a minimum, there are 142 bits of space between what is - * written and what is read in the overlain buffers, so the symbols cannot - * be overwritten by the compressed data. That space is actually 139 bits, - * due to the three-bit fixed-code block header. - * - * That covers the case where either Z_FIXED is specified, forcing fixed - * codes, or when the use of fixed codes is chosen, because that choice - * results in a smaller compressed block than dynamic codes. That latter - * condition then assures that the above analysis also covers all dynamic - * blocks. A dynamic-code block will only be chosen to be emitted if it has - * fewer bits than a fixed-code block would for the same set of symbols. - * Therefore its average symbol length is assured to be less than 31. So - * the compressed data for a dynamic block also cannot overwrite the - * symbols from which it is being constructed. - */ - - s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4); - s->pending_buf_size = (ulg)s->lit_bufsize * 4; - - if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || - s->pending_buf == Z_NULL) { - s->status = FINISH_STATE; - strm->msg = ERR_MSG(Z_MEM_ERROR); - deflateEnd (strm); - return Z_MEM_ERROR; - } - s->sym_buf = s->pending_buf + s->lit_bufsize; - s->sym_end = (s->lit_bufsize - 1) * 3; - /* We avoid equality with lit_bufsize*3 because of wraparound at 64K - * on 16 bit machines and because stored blocks are restricted to - * 64K-1 bytes. - */ - - s->level = level; - s->strategy = strategy; - s->method = (Byte)method; - - return deflateReset(strm); -} - -/* ========================================================================= - * Check for a valid deflate stream state. Return 0 if ok, 1 if not. - */ -local int deflateStateCheck (strm) - z_streamp strm; -{ - deflate_state *s; - if (strm == Z_NULL || - strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) - return 1; - s = strm->state; - if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE && -#ifdef GZIP - s->status != GZIP_STATE && -#endif - s->status != EXTRA_STATE && - s->status != NAME_STATE && - s->status != COMMENT_STATE && - s->status != HCRC_STATE && - s->status != BUSY_STATE && - s->status != FINISH_STATE)) - return 1; - return 0; -} - -/* ========================================================================= */ -int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) - z_streamp strm; - const Bytef *dictionary; - uInt dictLength; -{ - deflate_state *s; - uInt str, n; - int wrap; - unsigned avail; - z_const unsigned char *next; - - if (deflateStateCheck(strm) || dictionary == Z_NULL) - return Z_STREAM_ERROR; - s = strm->state; - wrap = s->wrap; - if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) - return Z_STREAM_ERROR; - - /* when using zlib wrappers, compute Adler-32 for provided dictionary */ - if (wrap == 1) - strm->adler = adler32(strm->adler, dictionary, dictLength); - s->wrap = 0; /* avoid computing Adler-32 in read_buf */ - - /* if dictionary would fill window, just replace the history */ - if (dictLength >= s->w_size) { - if (wrap == 0) { /* already empty otherwise */ - CLEAR_HASH(s); - s->strstart = 0; - s->block_start = 0L; - s->insert = 0; - } - dictionary += dictLength - s->w_size; /* use the tail */ - dictLength = s->w_size; - } - - /* insert dictionary into window and hash */ - avail = strm->avail_in; - next = strm->next_in; - strm->avail_in = dictLength; - strm->next_in = (z_const Bytef *)dictionary; - fill_window(s); - while (s->lookahead >= MIN_MATCH) { - str = s->strstart; - n = s->lookahead - (MIN_MATCH-1); - do { - UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); -#ifndef FASTEST - s->prev[str & s->w_mask] = s->head[s->ins_h]; -#endif - s->head[s->ins_h] = (Pos)str; - str++; - } while (--n); - s->strstart = str; - s->lookahead = MIN_MATCH-1; - fill_window(s); - } - s->strstart += s->lookahead; - s->block_start = (long)s->strstart; - s->insert = s->lookahead; - s->lookahead = 0; - s->match_length = s->prev_length = MIN_MATCH-1; - s->match_available = 0; - strm->next_in = next; - strm->avail_in = avail; - s->wrap = wrap; - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflateGetDictionary (strm, dictionary, dictLength) - z_streamp strm; - Bytef *dictionary; - uInt *dictLength; -{ - deflate_state *s; - uInt len; - - if (deflateStateCheck(strm)) - return Z_STREAM_ERROR; - s = strm->state; - len = s->strstart + s->lookahead; - if (len > s->w_size) - len = s->w_size; - if (dictionary != Z_NULL && len) - zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len); - if (dictLength != Z_NULL) - *dictLength = len; - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflateResetKeep (strm) - z_streamp strm; -{ - deflate_state *s; - - if (deflateStateCheck(strm)) { - return Z_STREAM_ERROR; - } - - strm->total_in = strm->total_out = 0; - strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ - strm->data_type = Z_UNKNOWN; - - s = (deflate_state *)strm->state; - s->pending = 0; - s->pending_out = s->pending_buf; - - if (s->wrap < 0) { - s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ - } - s->status = -#ifdef GZIP - s->wrap == 2 ? GZIP_STATE : -#endif - INIT_STATE; - strm->adler = -#ifdef GZIP - s->wrap == 2 ? crc32(0L, Z_NULL, 0) : -#endif - adler32(0L, Z_NULL, 0); - s->last_flush = -2; - - _tr_init(s); - - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflateReset (strm) - z_streamp strm; -{ - int ret; - - ret = deflateResetKeep(strm); - if (ret == Z_OK) - lm_init(strm->state); - return ret; -} - -/* ========================================================================= */ -int ZEXPORT deflateSetHeader (strm, head) - z_streamp strm; - gz_headerp head; -{ - if (deflateStateCheck(strm) || strm->state->wrap != 2) - return Z_STREAM_ERROR; - strm->state->gzhead = head; - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflatePending (strm, pending, bits) - unsigned *pending; - int *bits; - z_streamp strm; -{ - if (deflateStateCheck(strm)) return Z_STREAM_ERROR; - if (pending != Z_NULL) - *pending = strm->state->pending; - if (bits != Z_NULL) - *bits = strm->state->bi_valid; - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflatePrime (strm, bits, value) - z_streamp strm; - int bits; - int value; -{ - deflate_state *s; - int put; - - if (deflateStateCheck(strm)) return Z_STREAM_ERROR; - s = strm->state; - if (bits < 0 || bits > 16 || - s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3)) - return Z_BUF_ERROR; - do { - put = Buf_size - s->bi_valid; - if (put > bits) - put = bits; - s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); - s->bi_valid += put; - _tr_flush_bits(s); - value >>= put; - bits -= put; - } while (bits); - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflateParams(strm, level, strategy) - z_streamp strm; - int level; - int strategy; -{ - deflate_state *s; - compress_func func; - - if (deflateStateCheck(strm)) return Z_STREAM_ERROR; - s = strm->state; - -#ifdef FASTEST - if (level != 0) level = 1; -#else - if (level == Z_DEFAULT_COMPRESSION) level = 6; -#endif - if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { - return Z_STREAM_ERROR; - } - func = configuration_table[s->level].func; - - if ((strategy != s->strategy || func != configuration_table[level].func) && - s->last_flush != -2) { - /* Flush the last buffer: */ - int err = deflate(strm, Z_BLOCK); - if (err == Z_STREAM_ERROR) - return err; - if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead) - return Z_BUF_ERROR; - } - if (s->level != level) { - if (s->level == 0 && s->matches != 0) { - if (s->matches == 1) - slide_hash(s); - else - CLEAR_HASH(s); - s->matches = 0; - } - s->level = level; - s->max_lazy_match = configuration_table[level].max_lazy; - s->good_match = configuration_table[level].good_length; - s->nice_match = configuration_table[level].nice_length; - s->max_chain_length = configuration_table[level].max_chain; - } - s->strategy = strategy; - return Z_OK; -} - -/* ========================================================================= */ -int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) - z_streamp strm; - int good_length; - int max_lazy; - int nice_length; - int max_chain; -{ - deflate_state *s; - - if (deflateStateCheck(strm)) return Z_STREAM_ERROR; - s = strm->state; - s->good_match = (uInt)good_length; - s->max_lazy_match = (uInt)max_lazy; - s->nice_match = nice_length; - s->max_chain_length = (uInt)max_chain; - return Z_OK; -} - -/* ========================================================================= - * For the default windowBits of 15 and memLevel of 8, this function returns - * a close to exact, as well as small, upper bound on the compressed size. - * They are coded as constants here for a reason--if the #define's are - * changed, then this function needs to be changed as well. The return - * value for 15 and 8 only works for those exact settings. - * - * For any setting other than those defaults for windowBits and memLevel, - * the value returned is a conservative worst case for the maximum expansion - * resulting from using fixed blocks instead of stored blocks, which deflate - * can emit on compressed data for some combinations of the parameters. - * - * This function could be more sophisticated to provide closer upper bounds for - * every combination of windowBits and memLevel. But even the conservative - * upper bound of about 14% expansion does not seem onerous for output buffer - * allocation. - */ -uLong ZEXPORT deflateBound(strm, sourceLen) - z_streamp strm; - uLong sourceLen; -{ - deflate_state *s; - uLong complen, wraplen; - - /* conservative upper bound for compressed data */ - complen = sourceLen + - ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; - - /* if can't get parameters, return conservative bound plus zlib wrapper */ - if (deflateStateCheck(strm)) - return complen + 6; - - /* compute wrapper length */ - s = strm->state; - switch (s->wrap) { - case 0: /* raw deflate */ - wraplen = 0; - break; - case 1: /* zlib wrapper */ - wraplen = 6 + (s->strstart ? 4 : 0); - break; -#ifdef GZIP - case 2: /* gzip wrapper */ - wraplen = 18; - if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ - Bytef *str; - if (s->gzhead->extra != Z_NULL) - wraplen += 2 + s->gzhead->extra_len; - str = s->gzhead->name; - if (str != Z_NULL) - do { - wraplen++; - } while (*str++); - str = s->gzhead->comment; - if (str != Z_NULL) - do { - wraplen++; - } while (*str++); - if (s->gzhead->hcrc) - wraplen += 2; - } - break; -#endif - default: /* for compiler happiness */ - wraplen = 6; - } - - /* if not default parameters, return conservative bound */ - if (s->w_bits != 15 || s->hash_bits != 8 + 7) - return complen + wraplen; - - /* default settings: return tight bound for that case */ - return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + - (sourceLen >> 25) + 13 - 6 + wraplen; -} - -/* ========================================================================= - * Put a short in the pending buffer. The 16-bit value is put in MSB order. - * IN assertion: the stream state is correct and there is enough room in - * pending_buf. - */ -local void putShortMSB (s, b) - deflate_state *s; - uInt b; -{ - put_byte(s, (Byte)(b >> 8)); - put_byte(s, (Byte)(b & 0xff)); -} - -/* ========================================================================= - * Flush as much pending output as possible. All deflate() output, except for - * some deflate_stored() output, goes through this function so some - * applications may wish to modify it to avoid allocating a large - * strm->next_out buffer and copying into it. (See also read_buf()). - */ -local void flush_pending(strm) - z_streamp strm; -{ - unsigned len; - deflate_state *s = strm->state; - - _tr_flush_bits(s); - len = s->pending; - if (len > strm->avail_out) len = strm->avail_out; - if (len == 0) return; - - zmemcpy(strm->next_out, s->pending_out, len); - strm->next_out += len; - s->pending_out += len; - strm->total_out += len; - strm->avail_out -= len; - s->pending -= len; - if (s->pending == 0) { - s->pending_out = s->pending_buf; - } -} - -/* =========================================================================== - * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1]. - */ -#define HCRC_UPDATE(beg) \ - do { \ - if (s->gzhead->hcrc && s->pending > (beg)) \ - strm->adler = crc32(strm->adler, s->pending_buf + (beg), \ - s->pending - (beg)); \ - } while (0) - -/* ========================================================================= */ -int ZEXPORT deflate (strm, flush) - z_streamp strm; - int flush; -{ - int old_flush; /* value of flush param for previous deflate call */ - deflate_state *s; - - if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { - return Z_STREAM_ERROR; - } - s = strm->state; - - if (strm->next_out == Z_NULL || - (strm->avail_in != 0 && strm->next_in == Z_NULL) || - (s->status == FINISH_STATE && flush != Z_FINISH)) { - ERR_RETURN(strm, Z_STREAM_ERROR); - } - if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); - - old_flush = s->last_flush; - s->last_flush = flush; - - /* Flush as much pending output as possible */ - if (s->pending != 0) { - flush_pending(strm); - if (strm->avail_out == 0) { - /* Since avail_out is 0, deflate will be called again with - * more output space, but possibly with both pending and - * avail_in equal to zero. There won't be anything to do, - * but this is not an error situation so make sure we - * return OK instead of BUF_ERROR at next call of deflate: - */ - s->last_flush = -1; - return Z_OK; - } - - /* Make sure there is something to do and avoid duplicate consecutive - * flushes. For repeated and useless calls with Z_FINISH, we keep - * returning Z_STREAM_END instead of Z_BUF_ERROR. - */ - } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && - flush != Z_FINISH) { - ERR_RETURN(strm, Z_BUF_ERROR); - } - - /* User must not provide more input after the first FINISH: */ - if (s->status == FINISH_STATE && strm->avail_in != 0) { - ERR_RETURN(strm, Z_BUF_ERROR); - } - - /* Write the header */ - if (s->status == INIT_STATE && s->wrap == 0) - s->status = BUSY_STATE; - if (s->status == INIT_STATE) { - /* zlib header */ - uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; - uInt level_flags; - - if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) - level_flags = 0; - else if (s->level < 6) - level_flags = 1; - else if (s->level == 6) - level_flags = 2; - else - level_flags = 3; - header |= (level_flags << 6); - if (s->strstart != 0) header |= PRESET_DICT; - header += 31 - (header % 31); - - putShortMSB(s, header); - - /* Save the adler32 of the preset dictionary: */ - if (s->strstart != 0) { - putShortMSB(s, (uInt)(strm->adler >> 16)); - putShortMSB(s, (uInt)(strm->adler & 0xffff)); - } - strm->adler = adler32(0L, Z_NULL, 0); - s->status = BUSY_STATE; - - /* Compression must start with an empty pending buffer */ - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - } -#ifdef GZIP - if (s->status == GZIP_STATE) { - /* gzip header */ - strm->adler = crc32(0L, Z_NULL, 0); - put_byte(s, 31); - put_byte(s, 139); - put_byte(s, 8); - if (s->gzhead == Z_NULL) { - put_byte(s, 0); - put_byte(s, 0); - put_byte(s, 0); - put_byte(s, 0); - put_byte(s, 0); - put_byte(s, s->level == 9 ? 2 : - (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? - 4 : 0)); - put_byte(s, OS_CODE); - s->status = BUSY_STATE; - - /* Compression must start with an empty pending buffer */ - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - } - else { - put_byte(s, (s->gzhead->text ? 1 : 0) + - (s->gzhead->hcrc ? 2 : 0) + - (s->gzhead->extra == Z_NULL ? 0 : 4) + - (s->gzhead->name == Z_NULL ? 0 : 8) + - (s->gzhead->comment == Z_NULL ? 0 : 16) - ); - put_byte(s, (Byte)(s->gzhead->time & 0xff)); - put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); - put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); - put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); - put_byte(s, s->level == 9 ? 2 : - (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? - 4 : 0)); - put_byte(s, s->gzhead->os & 0xff); - if (s->gzhead->extra != Z_NULL) { - put_byte(s, s->gzhead->extra_len & 0xff); - put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); - } - if (s->gzhead->hcrc) - strm->adler = crc32(strm->adler, s->pending_buf, - s->pending); - s->gzindex = 0; - s->status = EXTRA_STATE; - } - } - if (s->status == EXTRA_STATE) { - if (s->gzhead->extra != Z_NULL) { - ulg beg = s->pending; /* start of bytes to update crc */ - uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex; - while (s->pending + left > s->pending_buf_size) { - uInt copy = s->pending_buf_size - s->pending; - zmemcpy(s->pending_buf + s->pending, - s->gzhead->extra + s->gzindex, copy); - s->pending = s->pending_buf_size; - HCRC_UPDATE(beg); - s->gzindex += copy; - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - beg = 0; - left -= copy; - } - zmemcpy(s->pending_buf + s->pending, - s->gzhead->extra + s->gzindex, left); - s->pending += left; - HCRC_UPDATE(beg); - s->gzindex = 0; - } - s->status = NAME_STATE; - } - if (s->status == NAME_STATE) { - if (s->gzhead->name != Z_NULL) { - ulg beg = s->pending; /* start of bytes to update crc */ - int val; - do { - if (s->pending == s->pending_buf_size) { - HCRC_UPDATE(beg); - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - beg = 0; - } - val = s->gzhead->name[s->gzindex++]; - put_byte(s, val); - } while (val != 0); - HCRC_UPDATE(beg); - s->gzindex = 0; - } - s->status = COMMENT_STATE; - } - if (s->status == COMMENT_STATE) { - if (s->gzhead->comment != Z_NULL) { - ulg beg = s->pending; /* start of bytes to update crc */ - int val; - do { - if (s->pending == s->pending_buf_size) { - HCRC_UPDATE(beg); - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - beg = 0; - } - val = s->gzhead->comment[s->gzindex++]; - put_byte(s, val); - } while (val != 0); - HCRC_UPDATE(beg); - } - s->status = HCRC_STATE; - } - if (s->status == HCRC_STATE) { - if (s->gzhead->hcrc) { - if (s->pending + 2 > s->pending_buf_size) { - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - } - put_byte(s, (Byte)(strm->adler & 0xff)); - put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); - strm->adler = crc32(0L, Z_NULL, 0); - } - s->status = BUSY_STATE; - - /* Compression must start with an empty pending buffer */ - flush_pending(strm); - if (s->pending != 0) { - s->last_flush = -1; - return Z_OK; - } - } -#endif - - /* Start a new block or continue the current one. - */ - if (strm->avail_in != 0 || s->lookahead != 0 || - (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { - block_state bstate; - - bstate = s->level == 0 ? deflate_stored(s, flush) : - s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : - s->strategy == Z_RLE ? deflate_rle(s, flush) : - (*(configuration_table[s->level].func))(s, flush); - - if (bstate == finish_started || bstate == finish_done) { - s->status = FINISH_STATE; - } - if (bstate == need_more || bstate == finish_started) { - if (strm->avail_out == 0) { - s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ - } - return Z_OK; - /* If flush != Z_NO_FLUSH && avail_out == 0, the next call - * of deflate should use the same flush parameter to make sure - * that the flush is complete. So we don't have to output an - * empty block here, this will be done at next call. This also - * ensures that for a very small output buffer, we emit at most - * one empty block. - */ - } - if (bstate == block_done) { - if (flush == Z_PARTIAL_FLUSH) { - _tr_align(s); - } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ - _tr_stored_block(s, (char*)0, 0L, 0); - /* For a full flush, this empty block will be recognized - * as a special marker by inflate_sync(). - */ - if (flush == Z_FULL_FLUSH) { - CLEAR_HASH(s); /* forget history */ - if (s->lookahead == 0) { - s->strstart = 0; - s->block_start = 0L; - s->insert = 0; - } - } - } - flush_pending(strm); - if (strm->avail_out == 0) { - s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ - return Z_OK; - } - } - } - - if (flush != Z_FINISH) return Z_OK; - if (s->wrap <= 0) return Z_STREAM_END; - - /* Write the trailer */ -#ifdef GZIP - if (s->wrap == 2) { - put_byte(s, (Byte)(strm->adler & 0xff)); - put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); - put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); - put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); - put_byte(s, (Byte)(strm->total_in & 0xff)); - put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); - put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); - put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); - } - else -#endif - { - putShortMSB(s, (uInt)(strm->adler >> 16)); - putShortMSB(s, (uInt)(strm->adler & 0xffff)); - } - flush_pending(strm); - /* If avail_out is zero, the application will call deflate again - * to flush the rest. - */ - if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ - return s->pending != 0 ? Z_OK : Z_STREAM_END; -} - -/* ========================================================================= */ -int ZEXPORT deflateEnd (strm) - z_streamp strm; -{ - int status; - - if (deflateStateCheck(strm)) return Z_STREAM_ERROR; - - status = strm->state->status; - - /* Deallocate in reverse order of allocations: */ - TRY_FREE(strm, strm->state->pending_buf); - TRY_FREE(strm, strm->state->head); - TRY_FREE(strm, strm->state->prev); - TRY_FREE(strm, strm->state->window); - - ZFREE(strm, strm->state); - strm->state = Z_NULL; - - return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; -} - -/* ========================================================================= - * Copy the source state to the destination state. - * To simplify the source, this is not supported for 16-bit MSDOS (which - * doesn't have enough memory anyway to duplicate compression states). - */ -int ZEXPORT deflateCopy (dest, source) - z_streamp dest; - z_streamp source; -{ -#ifdef MAXSEG_64K - return Z_STREAM_ERROR; -#else - deflate_state *ds; - deflate_state *ss; - - - if (deflateStateCheck(source) || dest == Z_NULL) { - return Z_STREAM_ERROR; - } - - ss = source->state; - - zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); - - ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); - if (ds == Z_NULL) return Z_MEM_ERROR; - dest->state = (struct internal_state FAR *) ds; - zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state)); - ds->strm = dest; - - ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); - ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); - ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); - ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4); - - if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || - ds->pending_buf == Z_NULL) { - deflateEnd (dest); - return Z_MEM_ERROR; - } - /* following zmemcpy do not work for 16-bit MSDOS */ - zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); - zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos)); - zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos)); - zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); - - ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); - ds->sym_buf = ds->pending_buf + ds->lit_bufsize; - - ds->l_desc.dyn_tree = ds->dyn_ltree; - ds->d_desc.dyn_tree = ds->dyn_dtree; - ds->bl_desc.dyn_tree = ds->bl_tree; - - return Z_OK; -#endif /* MAXSEG_64K */ -} - -/* =========================================================================== - * Read a new buffer from the current input stream, update the adler32 - * and total number of bytes read. All deflate() input goes through - * this function so some applications may wish to modify it to avoid - * allocating a large strm->next_in buffer and copying from it. - * (See also flush_pending()). - */ -local unsigned read_buf(strm, buf, size) - z_streamp strm; - Bytef *buf; - unsigned size; -{ - unsigned len = strm->avail_in; - - if (len > size) len = size; - if (len == 0) return 0; - - strm->avail_in -= len; - - zmemcpy(buf, strm->next_in, len); - if (strm->state->wrap == 1) { - strm->adler = adler32(strm->adler, buf, len); - } -#ifdef GZIP - else if (strm->state->wrap == 2) { - strm->adler = crc32(strm->adler, buf, len); - } -#endif - strm->next_in += len; - strm->total_in += len; - - return len; -} - -/* =========================================================================== - * Initialize the "longest match" routines for a new zlib stream - */ -local void lm_init (s) - deflate_state *s; -{ - s->window_size = (ulg)2L*s->w_size; - - CLEAR_HASH(s); - - /* Set the default configuration parameters: - */ - s->max_lazy_match = configuration_table[s->level].max_lazy; - s->good_match = configuration_table[s->level].good_length; - s->nice_match = configuration_table[s->level].nice_length; - s->max_chain_length = configuration_table[s->level].max_chain; - - s->strstart = 0; - s->block_start = 0L; - s->lookahead = 0; - s->insert = 0; - s->match_length = s->prev_length = MIN_MATCH-1; - s->match_available = 0; - s->ins_h = 0; -#ifndef FASTEST -#ifdef ASMV - match_init(); /* initialize the asm code */ -#endif -#endif -} - -#ifndef FASTEST -/* =========================================================================== - * Set match_start to the longest match starting at the given string and - * return its length. Matches shorter or equal to prev_length are discarded, - * in which case the result is equal to prev_length and match_start is - * garbage. - * IN assertions: cur_match is the head of the hash chain for the current - * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 - * OUT assertion: the match length is not greater than s->lookahead. - */ -#ifndef ASMV -/* For 80x86 and 680x0, an optimized version will be provided in match.asm or - * match.S. The code will be functionally equivalent. - */ -local uInt longest_match(s, cur_match) - deflate_state *s; - IPos cur_match; /* current match */ -{ - unsigned chain_length = s->max_chain_length;/* max hash chain length */ - register Bytef *scan = s->window + s->strstart; /* current string */ - register Bytef *match; /* matched string */ - register int len; /* length of current match */ - int best_len = (int)s->prev_length; /* best match length so far */ - int nice_match = s->nice_match; /* stop if match long enough */ - IPos limit = s->strstart > (IPos)MAX_DIST(s) ? - s->strstart - (IPos)MAX_DIST(s) : NIL; - /* Stop when cur_match becomes <= limit. To simplify the code, - * we prevent matches with the string of window index 0. - */ - Posf *prev = s->prev; - uInt wmask = s->w_mask; - -#ifdef UNALIGNED_OK - /* Compare two bytes at a time. Note: this is not always beneficial. - * Try with and without -DUNALIGNED_OK to check. - */ - register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; - register ush scan_start = *(ushf*)scan; - register ush scan_end = *(ushf*)(scan+best_len-1); -#else - register Bytef *strend = s->window + s->strstart + MAX_MATCH; - register Byte scan_end1 = scan[best_len-1]; - register Byte scan_end = scan[best_len]; -#endif - - /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. - * It is easy to get rid of this optimization if necessary. - */ - Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); - - /* Do not waste too much time if we already have a good match: */ - if (s->prev_length >= s->good_match) { - chain_length >>= 2; - } - /* Do not look for matches beyond the end of the input. This is necessary - * to make deflate deterministic. - */ - if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead; - - Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); - - do { - Assert(cur_match < s->strstart, "no future"); - match = s->window + cur_match; - - /* Skip to next match if the match length cannot increase - * or if the match length is less than 2. Note that the checks below - * for insufficient lookahead only occur occasionally for performance - * reasons. Therefore uninitialized memory will be accessed, and - * conditional jumps will be made that depend on those values. - * However the length of the match is limited to the lookahead, so - * the output of deflate is not affected by the uninitialized values. - */ -#if (defined(UNALIGNED_OK) && MAX_MATCH == 258) - /* This code assumes sizeof(unsigned short) == 2. Do not use - * UNALIGNED_OK if your compiler uses a different size. - */ - if (*(ushf*)(match+best_len-1) != scan_end || - *(ushf*)match != scan_start) continue; - - /* It is not necessary to compare scan[2] and match[2] since they are - * always equal when the other bytes match, given that the hash keys - * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at - * strstart+3, +5, ... up to strstart+257. We check for insufficient - * lookahead only every 4th comparison; the 128th check will be made - * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is - * necessary to put more guard bytes at the end of the window, or - * to check more often for insufficient lookahead. - */ - Assert(scan[2] == match[2], "scan[2]?"); - scan++, match++; - do { - } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && - *(ushf*)(scan+=2) == *(ushf*)(match+=2) && - *(ushf*)(scan+=2) == *(ushf*)(match+=2) && - *(ushf*)(scan+=2) == *(ushf*)(match+=2) && - scan < strend); - /* The funny "do {}" generates better code on most compilers */ - - /* Here, scan <= window+strstart+257 */ - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); - if (*scan == *match) scan++; - - len = (MAX_MATCH - 1) - (int)(strend-scan); - scan = strend - (MAX_MATCH-1); - -#else /* UNALIGNED_OK */ - - if (match[best_len] != scan_end || - match[best_len-1] != scan_end1 || - *match != *scan || - *++match != scan[1]) continue; - - /* The check at best_len-1 can be removed because it will be made - * again later. (This heuristic is not always a win.) - * It is not necessary to compare scan[2] and match[2] since they - * are always equal when the other bytes match, given that - * the hash keys are equal and that HASH_BITS >= 8. - */ - scan += 2, match++; - Assert(*scan == *match, "match[2]?"); - - /* We check for insufficient lookahead only every 8th comparison; - * the 256th check will be made at strstart+258. - */ - do { - } while (*++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - scan < strend); - - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); - - len = MAX_MATCH - (int)(strend - scan); - scan = strend - MAX_MATCH; - -#endif /* UNALIGNED_OK */ - - if (len > best_len) { - s->match_start = cur_match; - best_len = len; - if (len >= nice_match) break; -#ifdef UNALIGNED_OK - scan_end = *(ushf*)(scan+best_len-1); -#else - scan_end1 = scan[best_len-1]; - scan_end = scan[best_len]; -#endif - } - } while ((cur_match = prev[cur_match & wmask]) > limit - && --chain_length != 0); - - if ((uInt)best_len <= s->lookahead) return (uInt)best_len; - return s->lookahead; -} -#endif /* ASMV */ - -#else /* FASTEST */ - -/* --------------------------------------------------------------------------- - * Optimized version for FASTEST only - */ -local uInt longest_match(s, cur_match) - deflate_state *s; - IPos cur_match; /* current match */ -{ - register Bytef *scan = s->window + s->strstart; /* current string */ - register Bytef *match; /* matched string */ - register int len; /* length of current match */ - register Bytef *strend = s->window + s->strstart + MAX_MATCH; - - /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. - * It is easy to get rid of this optimization if necessary. - */ - Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); - - Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); - - Assert(cur_match < s->strstart, "no future"); - - match = s->window + cur_match; - - /* Return failure if the match length is less than 2: - */ - if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; - - /* The check at best_len-1 can be removed because it will be made - * again later. (This heuristic is not always a win.) - * It is not necessary to compare scan[2] and match[2] since they - * are always equal when the other bytes match, given that - * the hash keys are equal and that HASH_BITS >= 8. - */ - scan += 2, match += 2; - Assert(*scan == *match, "match[2]?"); - - /* We check for insufficient lookahead only every 8th comparison; - * the 256th check will be made at strstart+258. - */ - do { - } while (*++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - *++scan == *++match && *++scan == *++match && - scan < strend); - - Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); - - len = MAX_MATCH - (int)(strend - scan); - - if (len < MIN_MATCH) return MIN_MATCH - 1; - - s->match_start = cur_match; - return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; -} - -#endif /* FASTEST */ - -#ifdef ZLIB_DEBUG - -#define EQUAL 0 -/* result of memcmp for equal strings */ - -/* =========================================================================== - * Check that the match at match_start is indeed a match. - */ -local void check_match(s, start, match, length) - deflate_state *s; - IPos start, match; - int length; -{ - /* check that the match is indeed a match */ - if (zmemcmp(s->window + match, - s->window + start, length) != EQUAL) { - fprintf(stderr, " start %u, match %u, length %d\n", - start, match, length); - do { - fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); - } while (--length != 0); - z_error("invalid match"); - } - if (z_verbose > 1) { - fprintf(stderr,"\\[%d,%d]", start-match, length); - do { putc(s->window[start++], stderr); } while (--length != 0); - } -} -#else -# define check_match(s, start, match, length) -#endif /* ZLIB_DEBUG */ - -/* =========================================================================== - * Fill the window when the lookahead becomes insufficient. - * Updates strstart and lookahead. - * - * IN assertion: lookahead < MIN_LOOKAHEAD - * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD - * At least one byte has been read, or avail_in == 0; reads are - * performed for at least two bytes (required for the zip translate_eol - * option -- not supported here). - */ -local void fill_window(s) - deflate_state *s; -{ - unsigned n; - unsigned more; /* Amount of free space at the end of the window. */ - uInt wsize = s->w_size; - - Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); - - do { - more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); - - /* Deal with !@#$% 64K limit: */ - if (sizeof(int) <= 2) { - if (more == 0 && s->strstart == 0 && s->lookahead == 0) { - more = wsize; - - } else if (more == (unsigned)(-1)) { - /* Very unlikely, but possible on 16 bit machine if - * strstart == 0 && lookahead == 1 (input done a byte at time) - */ - more--; - } - } - - /* If the window is almost full and there is insufficient lookahead, - * move the upper half to the lower one to make room in the upper half. - */ - if (s->strstart >= wsize+MAX_DIST(s)) { - - zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more); - s->match_start -= wsize; - s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ - s->block_start -= (long) wsize; - if (s->insert > s->strstart) - s->insert = s->strstart; - slide_hash(s); - more += wsize; - } - if (s->strm->avail_in == 0) break; - - /* If there was no sliding: - * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && - * more == window_size - lookahead - strstart - * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) - * => more >= window_size - 2*WSIZE + 2 - * In the BIG_MEM or MMAP case (not yet supported), - * window_size == input_size + MIN_LOOKAHEAD && - * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. - * Otherwise, window_size == 2*WSIZE so more >= 2. - * If there was sliding, more >= WSIZE. So in all cases, more >= 2. - */ - Assert(more >= 2, "more < 2"); - - n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); - s->lookahead += n; - - /* Initialize the hash value now that we have some input: */ - if (s->lookahead + s->insert >= MIN_MATCH) { - uInt str = s->strstart - s->insert; - s->ins_h = s->window[str]; - UPDATE_HASH(s, s->ins_h, s->window[str + 1]); -#if MIN_MATCH != 3 - Call UPDATE_HASH() MIN_MATCH-3 more times -#endif - while (s->insert) { - UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); -#ifndef FASTEST - s->prev[str & s->w_mask] = s->head[s->ins_h]; -#endif - s->head[s->ins_h] = (Pos)str; - str++; - s->insert--; - if (s->lookahead + s->insert < MIN_MATCH) - break; - } - } - /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, - * but this is not important since only literal bytes will be emitted. - */ - - } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); - - /* If the WIN_INIT bytes after the end of the current data have never been - * written, then zero those bytes in order to avoid memory check reports of - * the use of uninitialized (or uninitialised as Julian writes) bytes by - * the longest match routines. Update the high water mark for the next - * time through here. WIN_INIT is set to MAX_MATCH since the longest match - * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. - */ - if (s->high_water < s->window_size) { - ulg curr = s->strstart + (ulg)(s->lookahead); - ulg init; - - if (s->high_water < curr) { - /* Previous high water mark below current data -- zero WIN_INIT - * bytes or up to end of window, whichever is less. - */ - init = s->window_size - curr; - if (init > WIN_INIT) - init = WIN_INIT; - zmemzero(s->window + curr, (unsigned)init); - s->high_water = curr + init; - } - else if (s->high_water < (ulg)curr + WIN_INIT) { - /* High water mark at or above current data, but below current data - * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up - * to end of window, whichever is less. - */ - init = (ulg)curr + WIN_INIT - s->high_water; - if (init > s->window_size - s->high_water) - init = s->window_size - s->high_water; - zmemzero(s->window + s->high_water, (unsigned)init); - s->high_water += init; - } - } - - Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, - "not enough room for search"); -} - -/* =========================================================================== - * Flush the current block, with given end-of-file flag. - * IN assertion: strstart is set to the end of the current match. - */ -#define FLUSH_BLOCK_ONLY(s, last) { \ - _tr_flush_block(s, (s->block_start >= 0L ? \ - (charf *)&s->window[(unsigned)s->block_start] : \ - (charf *)Z_NULL), \ - (ulg)((long)s->strstart - s->block_start), \ - (last)); \ - s->block_start = s->strstart; \ - flush_pending(s->strm); \ - Tracev((stderr,"[FLUSH]")); \ -} - -/* Same but force premature exit if necessary. */ -#define FLUSH_BLOCK(s, last) { \ - FLUSH_BLOCK_ONLY(s, last); \ - if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ -} - -/* Maximum stored block length in deflate format (not including header). */ -#define MAX_STORED 65535 - -/* Minimum of a and b. */ -#define MIN(a, b) ((a) > (b) ? (b) : (a)) - -/* =========================================================================== - * Copy without compression as much as possible from the input stream, return - * the current block state. - * - * In case deflateParams() is used to later switch to a non-zero compression - * level, s->matches (otherwise unused when storing) keeps track of the number - * of hash table slides to perform. If s->matches is 1, then one hash table - * slide will be done when switching. If s->matches is 2, the maximum value - * allowed here, then the hash table will be cleared, since two or more slides - * is the same as a clear. - * - * deflate_stored() is written to minimize the number of times an input byte is - * copied. It is most efficient with large input and output buffers, which - * maximizes the opportunites to have a single copy from next_in to next_out. - */ -local block_state deflate_stored(s, flush) - deflate_state *s; - int flush; -{ - /* Smallest worthy block size when not flushing or finishing. By default - * this is 32K. This can be as small as 507 bytes for memLevel == 1. For - * large input and output buffers, the stored block size will be larger. - */ - unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size); - - /* Copy as many min_block or larger stored blocks directly to next_out as - * possible. If flushing, copy the remaining available input to next_out as - * stored blocks, if there is enough space. - */ - unsigned len, left, have, last = 0; - unsigned used = s->strm->avail_in; - do { - /* Set len to the maximum size block that we can copy directly with the - * available input data and output space. Set left to how much of that - * would be copied from what's left in the window. - */ - len = MAX_STORED; /* maximum deflate stored block length */ - have = (s->bi_valid + 42) >> 3; /* number of header bytes */ - if (s->strm->avail_out < have) /* need room for header */ - break; - /* maximum stored block length that will fit in avail_out: */ - have = s->strm->avail_out - have; - left = s->strstart - s->block_start; /* bytes left in window */ - if (len > (ulg)left + s->strm->avail_in) - len = left + s->strm->avail_in; /* limit len to the input */ - if (len > have) - len = have; /* limit len to the output */ - - /* If the stored block would be less than min_block in length, or if - * unable to copy all of the available input when flushing, then try - * copying to the window and the pending buffer instead. Also don't - * write an empty block when flushing -- deflate() does that. - */ - if (len < min_block && ((len == 0 && flush != Z_FINISH) || - flush == Z_NO_FLUSH || - len != left + s->strm->avail_in)) - break; - - /* Make a dummy stored block in pending to get the header bytes, - * including any pending bits. This also updates the debugging counts. - */ - last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0; - _tr_stored_block(s, (char *)0, 0L, last); - - /* Replace the lengths in the dummy stored block with len. */ - s->pending_buf[s->pending - 4] = len; - s->pending_buf[s->pending - 3] = len >> 8; - s->pending_buf[s->pending - 2] = ~len; - s->pending_buf[s->pending - 1] = ~len >> 8; - - /* Write the stored block header bytes. */ - flush_pending(s->strm); - -#ifdef ZLIB_DEBUG - /* Update debugging counts for the data about to be copied. */ - s->compressed_len += len << 3; - s->bits_sent += len << 3; -#endif - - /* Copy uncompressed bytes from the window to next_out. */ - if (left) { - if (left > len) - left = len; - zmemcpy(s->strm->next_out, s->window + s->block_start, left); - s->strm->next_out += left; - s->strm->avail_out -= left; - s->strm->total_out += left; - s->block_start += left; - len -= left; - } - - /* Copy uncompressed bytes directly from next_in to next_out, updating - * the check value. - */ - if (len) { - read_buf(s->strm, s->strm->next_out, len); - s->strm->next_out += len; - s->strm->avail_out -= len; - s->strm->total_out += len; - } - } while (last == 0); - - /* Update the sliding window with the last s->w_size bytes of the copied - * data, or append all of the copied data to the existing window if less - * than s->w_size bytes were copied. Also update the number of bytes to - * insert in the hash tables, in the event that deflateParams() switches to - * a non-zero compression level. - */ - used -= s->strm->avail_in; /* number of input bytes directly copied */ - if (used) { - /* If any input was used, then no unused input remains in the window, - * therefore s->block_start == s->strstart. - */ - if (used >= s->w_size) { /* supplant the previous history */ - s->matches = 2; /* clear hash */ - zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); - s->strstart = s->w_size; - s->insert = s->strstart; - } - else { - if (s->window_size - s->strstart <= used) { - /* Slide the window down. */ - s->strstart -= s->w_size; - zmemcpy(s->window, s->window + s->w_size, s->strstart); - if (s->matches < 2) - s->matches++; /* add a pending slide_hash() */ - if (s->insert > s->strstart) - s->insert = s->strstart; - } - zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); - s->strstart += used; - s->insert += MIN(used, s->w_size - s->insert); - } - s->block_start = s->strstart; - } - if (s->high_water < s->strstart) - s->high_water = s->strstart; - - /* If the last block was written to next_out, then done. */ - if (last) - return finish_done; - - /* If flushing and all input has been consumed, then done. */ - if (flush != Z_NO_FLUSH && flush != Z_FINISH && - s->strm->avail_in == 0 && (long)s->strstart == s->block_start) - return block_done; - - /* Fill the window with any remaining input. */ - have = s->window_size - s->strstart; - if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { - /* Slide the window down. */ - s->block_start -= s->w_size; - s->strstart -= s->w_size; - zmemcpy(s->window, s->window + s->w_size, s->strstart); - if (s->matches < 2) - s->matches++; /* add a pending slide_hash() */ - have += s->w_size; /* more space now */ - if (s->insert > s->strstart) - s->insert = s->strstart; - } - if (have > s->strm->avail_in) - have = s->strm->avail_in; - if (have) { - read_buf(s->strm, s->window + s->strstart, have); - s->strstart += have; - s->insert += MIN(have, s->w_size - s->insert); - } - if (s->high_water < s->strstart) - s->high_water = s->strstart; - - /* There was not enough avail_out to write a complete worthy or flushed - * stored block to next_out. Write a stored block to pending instead, if we - * have enough input for a worthy block, or if flushing and there is enough - * room for the remaining input as a stored block in the pending buffer. - */ - have = (s->bi_valid + 42) >> 3; /* number of header bytes */ - /* maximum stored block length that will fit in pending: */ - have = MIN(s->pending_buf_size - have, MAX_STORED); - min_block = MIN(have, s->w_size); - left = s->strstart - s->block_start; - if (left >= min_block || - ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH && - s->strm->avail_in == 0 && left <= have)) { - len = MIN(left, have); - last = flush == Z_FINISH && s->strm->avail_in == 0 && - len == left ? 1 : 0; - _tr_stored_block(s, (charf *)s->window + s->block_start, len, last); - s->block_start += len; - flush_pending(s->strm); - } - - /* We've done all we can with the available input and output. */ - return last ? finish_started : need_more; -} - -/* =========================================================================== - * Compress as much as possible from the input stream, return the current - * block state. - * This function does not perform lazy evaluation of matches and inserts - * new strings in the dictionary only for unmatched strings or for short - * matches. It is used only for the fast compression options. - */ -local block_state deflate_fast(s, flush) - deflate_state *s; - int flush; -{ - IPos hash_head; /* head of the hash chain */ - int bflush; /* set if current block must be flushed */ - - for (;;) { - /* Make sure that we always have enough lookahead, except - * at the end of the input file. We need MAX_MATCH bytes - * for the next match, plus MIN_MATCH bytes to insert the - * string following the next match. - */ - if (s->lookahead < MIN_LOOKAHEAD) { - fill_window(s); - if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { - return need_more; - } - if (s->lookahead == 0) break; /* flush the current block */ - } - - /* Insert the string window[strstart .. strstart+2] in the - * dictionary, and set hash_head to the head of the hash chain: - */ - hash_head = NIL; - if (s->lookahead >= MIN_MATCH) { - INSERT_STRING(s, s->strstart, hash_head); - } - - /* Find the longest match, discarding those <= prev_length. - * At this point we have always match_length < MIN_MATCH - */ - if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { - /* To simplify the code, we prevent matches with the string - * of window index 0 (in particular we have to avoid a match - * of the string with itself at the start of the input file). - */ - s->match_length = longest_match (s, hash_head); - /* longest_match() sets match_start */ - } - if (s->match_length >= MIN_MATCH) { - check_match(s, s->strstart, s->match_start, s->match_length); - - _tr_tally_dist(s, s->strstart - s->match_start, - s->match_length - MIN_MATCH, bflush); - - s->lookahead -= s->match_length; - - /* Insert new strings in the hash table only if the match length - * is not too large. This saves time but degrades compression. - */ -#ifndef FASTEST - if (s->match_length <= s->max_insert_length && - s->lookahead >= MIN_MATCH) { - s->match_length--; /* string at strstart already in table */ - do { - s->strstart++; - INSERT_STRING(s, s->strstart, hash_head); - /* strstart never exceeds WSIZE-MAX_MATCH, so there are - * always MIN_MATCH bytes ahead. - */ - } while (--s->match_length != 0); - s->strstart++; - } else -#endif - { - s->strstart += s->match_length; - s->match_length = 0; - s->ins_h = s->window[s->strstart]; - UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); -#if MIN_MATCH != 3 - Call UPDATE_HASH() MIN_MATCH-3 more times -#endif - /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not - * matter since it will be recomputed at next deflate call. - */ - } - } else { - /* No match, output a literal byte */ - Tracevv((stderr,"%c", s->window[s->strstart])); - _tr_tally_lit (s, s->window[s->strstart], bflush); - s->lookahead--; - s->strstart++; - } - if (bflush) FLUSH_BLOCK(s, 0); - } - s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; - if (flush == Z_FINISH) { - FLUSH_BLOCK(s, 1); - return finish_done; - } - if (s->sym_next) - FLUSH_BLOCK(s, 0); - return block_done; -} - -#ifndef FASTEST -/* =========================================================================== - * Same as above, but achieves better compression. We use a lazy - * evaluation for matches: a match is finally adopted only if there is - * no better match at the next window position. - */ -local block_state deflate_slow(s, flush) - deflate_state *s; - int flush; -{ - IPos hash_head; /* head of hash chain */ - int bflush; /* set if current block must be flushed */ - - /* Process the input block. */ - for (;;) { - /* Make sure that we always have enough lookahead, except - * at the end of the input file. We need MAX_MATCH bytes - * for the next match, plus MIN_MATCH bytes to insert the - * string following the next match. - */ - if (s->lookahead < MIN_LOOKAHEAD) { - fill_window(s); - if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { - return need_more; - } - if (s->lookahead == 0) break; /* flush the current block */ - } - - /* Insert the string window[strstart .. strstart+2] in the - * dictionary, and set hash_head to the head of the hash chain: - */ - hash_head = NIL; - if (s->lookahead >= MIN_MATCH) { - INSERT_STRING(s, s->strstart, hash_head); - } - - /* Find the longest match, discarding those <= prev_length. - */ - s->prev_length = s->match_length, s->prev_match = s->match_start; - s->match_length = MIN_MATCH-1; - - if (hash_head != NIL && s->prev_length < s->max_lazy_match && - s->strstart - hash_head <= MAX_DIST(s)) { - /* To simplify the code, we prevent matches with the string - * of window index 0 (in particular we have to avoid a match - * of the string with itself at the start of the input file). - */ - s->match_length = longest_match (s, hash_head); - /* longest_match() sets match_start */ - - if (s->match_length <= 5 && (s->strategy == Z_FILTERED -#if TOO_FAR <= 32767 - || (s->match_length == MIN_MATCH && - s->strstart - s->match_start > TOO_FAR) -#endif - )) { - - /* If prev_match is also MIN_MATCH, match_start is garbage - * but we will ignore the current match anyway. - */ - s->match_length = MIN_MATCH-1; - } - } - /* If there was a match at the previous step and the current - * match is not better, output the previous match: - */ - if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { - uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; - /* Do not insert strings in hash table beyond this. */ - - check_match(s, s->strstart-1, s->prev_match, s->prev_length); - - _tr_tally_dist(s, s->strstart -1 - s->prev_match, - s->prev_length - MIN_MATCH, bflush); - - /* Insert in hash table all strings up to the end of the match. - * strstart-1 and strstart are already inserted. If there is not - * enough lookahead, the last two strings are not inserted in - * the hash table. - */ - s->lookahead -= s->prev_length-1; - s->prev_length -= 2; - do { - if (++s->strstart <= max_insert) { - INSERT_STRING(s, s->strstart, hash_head); - } - } while (--s->prev_length != 0); - s->match_available = 0; - s->match_length = MIN_MATCH-1; - s->strstart++; - - if (bflush) FLUSH_BLOCK(s, 0); - - } else if (s->match_available) { - /* If there was no match at the previous position, output a - * single literal. If there was a match but the current match - * is longer, truncate the previous match to a single literal. - */ - Tracevv((stderr,"%c", s->window[s->strstart-1])); - _tr_tally_lit(s, s->window[s->strstart-1], bflush); - if (bflush) { - FLUSH_BLOCK_ONLY(s, 0); - } - s->strstart++; - s->lookahead--; - if (s->strm->avail_out == 0) return need_more; - } else { - /* There is no previous match to compare with, wait for - * the next step to decide. - */ - s->match_available = 1; - s->strstart++; - s->lookahead--; - } - } - Assert (flush != Z_NO_FLUSH, "no flush?"); - if (s->match_available) { - Tracevv((stderr,"%c", s->window[s->strstart-1])); - _tr_tally_lit(s, s->window[s->strstart-1], bflush); - s->match_available = 0; - } - s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; - if (flush == Z_FINISH) { - FLUSH_BLOCK(s, 1); - return finish_done; - } - if (s->sym_next) - FLUSH_BLOCK(s, 0); - return block_done; -} -#endif /* FASTEST */ - -/* =========================================================================== - * For Z_RLE, simply look for runs of bytes, generate matches only of distance - * one. Do not maintain a hash table. (It will be regenerated if this run of - * deflate switches away from Z_RLE.) - */ -local block_state deflate_rle(s, flush) - deflate_state *s; - int flush; -{ - int bflush; /* set if current block must be flushed */ - uInt prev; /* byte at distance one to match */ - Bytef *scan, *strend; /* scan goes up to strend for length of run */ - - for (;;) { - /* Make sure that we always have enough lookahead, except - * at the end of the input file. We need MAX_MATCH bytes - * for the longest run, plus one for the unrolled loop. - */ - if (s->lookahead <= MAX_MATCH) { - fill_window(s); - if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { - return need_more; - } - if (s->lookahead == 0) break; /* flush the current block */ - } - - /* See how many times the previous byte repeats */ - s->match_length = 0; - if (s->lookahead >= MIN_MATCH && s->strstart > 0) { - scan = s->window + s->strstart - 1; - prev = *scan; - if (prev == *++scan && prev == *++scan && prev == *++scan) { - strend = s->window + s->strstart + MAX_MATCH; - do { - } while (prev == *++scan && prev == *++scan && - prev == *++scan && prev == *++scan && - prev == *++scan && prev == *++scan && - prev == *++scan && prev == *++scan && - scan < strend); - s->match_length = MAX_MATCH - (uInt)(strend - scan); - if (s->match_length > s->lookahead) - s->match_length = s->lookahead; - } - Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan"); - } - - /* Emit match if have run of MIN_MATCH or longer, else emit literal */ - if (s->match_length >= MIN_MATCH) { - check_match(s, s->strstart, s->strstart - 1, s->match_length); - - _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); - - s->lookahead -= s->match_length; - s->strstart += s->match_length; - s->match_length = 0; - } else { - /* No match, output a literal byte */ - Tracevv((stderr,"%c", s->window[s->strstart])); - _tr_tally_lit (s, s->window[s->strstart], bflush); - s->lookahead--; - s->strstart++; - } - if (bflush) FLUSH_BLOCK(s, 0); - } - s->insert = 0; - if (flush == Z_FINISH) { - FLUSH_BLOCK(s, 1); - return finish_done; - } - if (s->sym_next) - FLUSH_BLOCK(s, 0); - return block_done; -} - -/* =========================================================================== - * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. - * (It will be regenerated if this run of deflate switches away from Huffman.) - */ -local block_state deflate_huff(s, flush) - deflate_state *s; - int flush; -{ - int bflush; /* set if current block must be flushed */ - - for (;;) { - /* Make sure that we have a literal to write. */ - if (s->lookahead == 0) { - fill_window(s); - if (s->lookahead == 0) { - if (flush == Z_NO_FLUSH) - return need_more; - break; /* flush the current block */ - } - } - - /* Output a literal byte */ - s->match_length = 0; - Tracevv((stderr,"%c", s->window[s->strstart])); - _tr_tally_lit (s, s->window[s->strstart], bflush); - s->lookahead--; - s->strstart++; - if (bflush) FLUSH_BLOCK(s, 0); - } - s->insert = 0; - if (flush == Z_FINISH) { - FLUSH_BLOCK(s, 1); - return finish_done; - } - if (s->sym_next) - FLUSH_BLOCK(s, 0); - return block_done; -} +/* deflate.c -- compress data using the deflation algorithm
+ * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/*
+ * ALGORITHM
+ *
+ * The "deflation" process depends on being able to identify portions
+ * of the input text which are identical to earlier input (within a
+ * sliding window trailing behind the input currently being processed).
+ *
+ * The most straightforward technique turns out to be the fastest for
+ * most input files: try all possible matches and select the longest.
+ * The key feature of this algorithm is that insertions into the string
+ * dictionary are very simple and thus fast, and deletions are avoided
+ * completely. Insertions are performed at each input character, whereas
+ * string matches are performed only when the previous match ends. So it
+ * is preferable to spend more time in matches to allow very fast string
+ * insertions and avoid deletions. The matching algorithm for small
+ * strings is inspired from that of Rabin & Karp. A brute force approach
+ * is used to find longer strings when a small match has been found.
+ * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
+ * (by Leonid Broukhis).
+ * A previous version of this file used a more sophisticated algorithm
+ * (by Fiala and Greene) which is guaranteed to run in linear amortized
+ * time, but has a larger average cost, uses more memory and is patented.
+ * However the F&G algorithm may be faster for some highly redundant
+ * files if the parameter max_chain_length (described below) is too large.
+ *
+ * ACKNOWLEDGEMENTS
+ *
+ * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
+ * I found it in 'freeze' written by Leonid Broukhis.
+ * Thanks to many people for bug reports and testing.
+ *
+ * REFERENCES
+ *
+ * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
+ * Available in http://tools.ietf.org/html/rfc1951
+ *
+ * A description of the Rabin and Karp algorithm is given in the book
+ * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
+ *
+ * Fiala,E.R., and Greene,D.H.
+ * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
+ *
+ */
+
+/* @(#) $Id$ */
+
+#include "deflate.h"
+
+const char deflate_copyright[] =
+ " deflate 1.2.13 Copyright 1995-2022 Jean-loup Gailly and Mark Adler ";
+/*
+ If you use the zlib library in a product, an acknowledgment is welcome
+ in the documentation of your product. If for some reason you cannot
+ include such an acknowledgment, I would appreciate that you keep this
+ copyright string in the executable of your product.
+ */
+
+/* ===========================================================================
+ * Function prototypes.
+ */
+typedef enum {
+ need_more, /* block not completed, need more input or more output */
+ block_done, /* block flush performed */
+ finish_started, /* finish started, need only more output at next deflate */
+ finish_done /* finish done, accept no more input or output */
+} block_state;
+
+typedef block_state (*compress_func) OF((deflate_state *s, int flush));
+/* Compression function. Returns the block state after the call. */
+
+local int deflateStateCheck OF((z_streamp strm));
+local void slide_hash OF((deflate_state *s));
+local void fill_window OF((deflate_state *s));
+local block_state deflate_stored OF((deflate_state *s, int flush));
+local block_state deflate_fast OF((deflate_state *s, int flush));
+#ifndef FASTEST
+local block_state deflate_slow OF((deflate_state *s, int flush));
+#endif
+local block_state deflate_rle OF((deflate_state *s, int flush));
+local block_state deflate_huff OF((deflate_state *s, int flush));
+local void lm_init OF((deflate_state *s));
+local void putShortMSB OF((deflate_state *s, uInt b));
+local void flush_pending OF((z_streamp strm));
+local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
+local uInt longest_match OF((deflate_state *s, IPos cur_match));
+
+#ifdef ZLIB_DEBUG
+local void check_match OF((deflate_state *s, IPos start, IPos match,
+ int length));
+#endif
+
+/* ===========================================================================
+ * Local data
+ */
+
+#define NIL 0
+/* Tail of hash chains */
+
+#ifndef TOO_FAR
+# define TOO_FAR 4096
+#endif
+/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
+
+/* Values for max_lazy_match, good_match and max_chain_length, depending on
+ * the desired pack level (0..9). The values given below have been tuned to
+ * exclude worst case performance for pathological files. Better values may be
+ * found for specific files.
+ */
+typedef struct config_s {
+ ush good_length; /* reduce lazy search above this match length */
+ ush max_lazy; /* do not perform lazy search above this match length */
+ ush nice_length; /* quit search above this match length */
+ ush max_chain;
+ compress_func func;
+} config;
+
+#ifdef FASTEST
+local const config configuration_table[2] = {
+/* good lazy nice chain */
+/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
+/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
+#else
+local const config configuration_table[10] = {
+/* good lazy nice chain */
+/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
+/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
+/* 2 */ {4, 5, 16, 8, deflate_fast},
+/* 3 */ {4, 6, 32, 32, deflate_fast},
+
+/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
+/* 5 */ {8, 16, 32, 32, deflate_slow},
+/* 6 */ {8, 16, 128, 128, deflate_slow},
+/* 7 */ {8, 32, 128, 256, deflate_slow},
+/* 8 */ {32, 128, 258, 1024, deflate_slow},
+/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
+#endif
+
+/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
+ * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
+ * meaning.
+ */
+
+/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
+#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
+
+/* ===========================================================================
+ * Update a hash value with the given input byte
+ * IN assertion: all calls to UPDATE_HASH are made with consecutive input
+ * characters, so that a running hash key can be computed from the previous
+ * key instead of complete recalculation each time.
+ */
+#define UPDATE_HASH(s,h,c) (h = (((h) << s->hash_shift) ^ (c)) & s->hash_mask)
+
+
+/* ===========================================================================
+ * Insert string str in the dictionary and set match_head to the previous head
+ * of the hash chain (the most recent string with same hash key). Return
+ * the previous length of the hash chain.
+ * If this file is compiled with -DFASTEST, the compression level is forced
+ * to 1, and no hash chains are maintained.
+ * IN assertion: all calls to INSERT_STRING are made with consecutive input
+ * characters and the first MIN_MATCH bytes of str are valid (except for
+ * the last MIN_MATCH-1 bytes of the input file).
+ */
+#ifdef FASTEST
+#define INSERT_STRING(s, str, match_head) \
+ (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
+ match_head = s->head[s->ins_h], \
+ s->head[s->ins_h] = (Pos)(str))
+#else
+#define INSERT_STRING(s, str, match_head) \
+ (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
+ match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
+ s->head[s->ins_h] = (Pos)(str))
+#endif
+
+/* ===========================================================================
+ * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
+ * prev[] will be initialized on the fly.
+ */
+#define CLEAR_HASH(s) \
+ do { \
+ s->head[s->hash_size - 1] = NIL; \
+ zmemzero((Bytef *)s->head, \
+ (unsigned)(s->hash_size - 1)*sizeof(*s->head)); \
+ } while (0)
+
+/* ===========================================================================
+ * Slide the hash table when sliding the window down (could be avoided with 32
+ * bit values at the expense of memory usage). We slide even when level == 0 to
+ * keep the hash table consistent if we switch back to level > 0 later.
+ */
+local void slide_hash(s)
+ deflate_state *s;
+{
+ unsigned n, m;
+ Posf *p;
+ uInt wsize = s->w_size;
+
+ n = s->hash_size;
+ p = &s->head[n];
+ do {
+ m = *--p;
+ *p = (Pos)(m >= wsize ? m - wsize : NIL);
+ } while (--n);
+ n = wsize;
+#ifndef FASTEST
+ p = &s->prev[n];
+ do {
+ m = *--p;
+ *p = (Pos)(m >= wsize ? m - wsize : NIL);
+ /* If n is not on any hash chain, prev[n] is garbage but
+ * its value will never be used.
+ */
+ } while (--n);
+#endif
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateInit_(strm, level, version, stream_size)
+ z_streamp strm;
+ int level;
+ const char *version;
+ int stream_size;
+{
+ return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
+ Z_DEFAULT_STRATEGY, version, stream_size);
+ /* To do: ignore strm->next_in if we use it as window */
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
+ version, stream_size)
+ z_streamp strm;
+ int level;
+ int method;
+ int windowBits;
+ int memLevel;
+ int strategy;
+ const char *version;
+ int stream_size;
+{
+ deflate_state *s;
+ int wrap = 1;
+ static const char my_version[] = ZLIB_VERSION;
+
+ if (version == Z_NULL || version[0] != my_version[0] ||
+ stream_size != sizeof(z_stream)) {
+ return Z_VERSION_ERROR;
+ }
+ if (strm == Z_NULL) return Z_STREAM_ERROR;
+
+ strm->msg = Z_NULL;
+ if (strm->zalloc == (alloc_func)0) {
+#ifdef Z_SOLO
+ return Z_STREAM_ERROR;
+#else
+ strm->zalloc = zcalloc;
+ strm->opaque = (voidpf)0;
+#endif
+ }
+ if (strm->zfree == (free_func)0)
+#ifdef Z_SOLO
+ return Z_STREAM_ERROR;
+#else
+ strm->zfree = zcfree;
+#endif
+
+#ifdef FASTEST
+ if (level != 0) level = 1;
+#else
+ if (level == Z_DEFAULT_COMPRESSION) level = 6;
+#endif
+
+ if (windowBits < 0) { /* suppress zlib wrapper */
+ wrap = 0;
+ if (windowBits < -15)
+ return Z_STREAM_ERROR;
+ windowBits = -windowBits;
+ }
+#ifdef GZIP
+ else if (windowBits > 15) {
+ wrap = 2; /* write gzip wrapper instead */
+ windowBits -= 16;
+ }
+#endif
+ if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
+ windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
+ strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
+ return Z_STREAM_ERROR;
+ }
+ if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
+ s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
+ if (s == Z_NULL) return Z_MEM_ERROR;
+ strm->state = (struct internal_state FAR *)s;
+ s->strm = strm;
+ s->status = INIT_STATE; /* to pass state test in deflateReset() */
+
+ s->wrap = wrap;
+ s->gzhead = Z_NULL;
+ s->w_bits = (uInt)windowBits;
+ s->w_size = 1 << s->w_bits;
+ s->w_mask = s->w_size - 1;
+
+ s->hash_bits = (uInt)memLevel + 7;
+ s->hash_size = 1 << s->hash_bits;
+ s->hash_mask = s->hash_size - 1;
+ s->hash_shift = ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH);
+
+ s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
+ s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
+ s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
+
+ s->high_water = 0; /* nothing written to s->window yet */
+
+ s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
+
+ /* We overlay pending_buf and sym_buf. This works since the average size
+ * for length/distance pairs over any compressed block is assured to be 31
+ * bits or less.
+ *
+ * Analysis: The longest fixed codes are a length code of 8 bits plus 5
+ * extra bits, for lengths 131 to 257. The longest fixed distance codes are
+ * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
+ * possible fixed-codes length/distance pair is then 31 bits total.
+ *
+ * sym_buf starts one-fourth of the way into pending_buf. So there are
+ * three bytes in sym_buf for every four bytes in pending_buf. Each symbol
+ * in sym_buf is three bytes -- two for the distance and one for the
+ * literal/length. As each symbol is consumed, the pointer to the next
+ * sym_buf value to read moves forward three bytes. From that symbol, up to
+ * 31 bits are written to pending_buf. The closest the written pending_buf
+ * bits gets to the next sym_buf symbol to read is just before the last
+ * code is written. At that time, 31*(n - 2) bits have been written, just
+ * after 24*(n - 2) bits have been consumed from sym_buf. sym_buf starts at
+ * 8*n bits into pending_buf. (Note that the symbol buffer fills when n - 1
+ * symbols are written.) The closest the writing gets to what is unread is
+ * then n + 14 bits. Here n is lit_bufsize, which is 16384 by default, and
+ * can range from 128 to 32768.
+ *
+ * Therefore, at a minimum, there are 142 bits of space between what is
+ * written and what is read in the overlain buffers, so the symbols cannot
+ * be overwritten by the compressed data. That space is actually 139 bits,
+ * due to the three-bit fixed-code block header.
+ *
+ * That covers the case where either Z_FIXED is specified, forcing fixed
+ * codes, or when the use of fixed codes is chosen, because that choice
+ * results in a smaller compressed block than dynamic codes. That latter
+ * condition then assures that the above analysis also covers all dynamic
+ * blocks. A dynamic-code block will only be chosen to be emitted if it has
+ * fewer bits than a fixed-code block would for the same set of symbols.
+ * Therefore its average symbol length is assured to be less than 31. So
+ * the compressed data for a dynamic block also cannot overwrite the
+ * symbols from which it is being constructed.
+ */
+
+ s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4);
+ s->pending_buf_size = (ulg)s->lit_bufsize * 4;
+
+ if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
+ s->pending_buf == Z_NULL) {
+ s->status = FINISH_STATE;
+ strm->msg = ERR_MSG(Z_MEM_ERROR);
+ deflateEnd (strm);
+ return Z_MEM_ERROR;
+ }
+ s->sym_buf = s->pending_buf + s->lit_bufsize;
+ s->sym_end = (s->lit_bufsize - 1) * 3;
+ /* We avoid equality with lit_bufsize*3 because of wraparound at 64K
+ * on 16 bit machines and because stored blocks are restricted to
+ * 64K-1 bytes.
+ */
+
+ s->level = level;
+ s->strategy = strategy;
+ s->method = (Byte)method;
+
+ return deflateReset(strm);
+}
+
+/* =========================================================================
+ * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
+ */
+local int deflateStateCheck(strm)
+ z_streamp strm;
+{
+ deflate_state *s;
+ if (strm == Z_NULL ||
+ strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
+ return 1;
+ s = strm->state;
+ if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
+#ifdef GZIP
+ s->status != GZIP_STATE &&
+#endif
+ s->status != EXTRA_STATE &&
+ s->status != NAME_STATE &&
+ s->status != COMMENT_STATE &&
+ s->status != HCRC_STATE &&
+ s->status != BUSY_STATE &&
+ s->status != FINISH_STATE))
+ return 1;
+ return 0;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateSetDictionary(strm, dictionary, dictLength)
+ z_streamp strm;
+ const Bytef *dictionary;
+ uInt dictLength;
+{
+ deflate_state *s;
+ uInt str, n;
+ int wrap;
+ unsigned avail;
+ z_const unsigned char *next;
+
+ if (deflateStateCheck(strm) || dictionary == Z_NULL)
+ return Z_STREAM_ERROR;
+ s = strm->state;
+ wrap = s->wrap;
+ if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
+ return Z_STREAM_ERROR;
+
+ /* when using zlib wrappers, compute Adler-32 for provided dictionary */
+ if (wrap == 1)
+ strm->adler = adler32(strm->adler, dictionary, dictLength);
+ s->wrap = 0; /* avoid computing Adler-32 in read_buf */
+
+ /* if dictionary would fill window, just replace the history */
+ if (dictLength >= s->w_size) {
+ if (wrap == 0) { /* already empty otherwise */
+ CLEAR_HASH(s);
+ s->strstart = 0;
+ s->block_start = 0L;
+ s->insert = 0;
+ }
+ dictionary += dictLength - s->w_size; /* use the tail */
+ dictLength = s->w_size;
+ }
+
+ /* insert dictionary into window and hash */
+ avail = strm->avail_in;
+ next = strm->next_in;
+ strm->avail_in = dictLength;
+ strm->next_in = (z_const Bytef *)dictionary;
+ fill_window(s);
+ while (s->lookahead >= MIN_MATCH) {
+ str = s->strstart;
+ n = s->lookahead - (MIN_MATCH-1);
+ do {
+ UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+ s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+ s->head[s->ins_h] = (Pos)str;
+ str++;
+ } while (--n);
+ s->strstart = str;
+ s->lookahead = MIN_MATCH-1;
+ fill_window(s);
+ }
+ s->strstart += s->lookahead;
+ s->block_start = (long)s->strstart;
+ s->insert = s->lookahead;
+ s->lookahead = 0;
+ s->match_length = s->prev_length = MIN_MATCH-1;
+ s->match_available = 0;
+ strm->next_in = next;
+ strm->avail_in = avail;
+ s->wrap = wrap;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateGetDictionary(strm, dictionary, dictLength)
+ z_streamp strm;
+ Bytef *dictionary;
+ uInt *dictLength;
+{
+ deflate_state *s;
+ uInt len;
+
+ if (deflateStateCheck(strm))
+ return Z_STREAM_ERROR;
+ s = strm->state;
+ len = s->strstart + s->lookahead;
+ if (len > s->w_size)
+ len = s->w_size;
+ if (dictionary != Z_NULL && len)
+ zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
+ if (dictLength != Z_NULL)
+ *dictLength = len;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateResetKeep(strm)
+ z_streamp strm;
+{
+ deflate_state *s;
+
+ if (deflateStateCheck(strm)) {
+ return Z_STREAM_ERROR;
+ }
+
+ strm->total_in = strm->total_out = 0;
+ strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
+ strm->data_type = Z_UNKNOWN;
+
+ s = (deflate_state *)strm->state;
+ s->pending = 0;
+ s->pending_out = s->pending_buf;
+
+ if (s->wrap < 0) {
+ s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
+ }
+ s->status =
+#ifdef GZIP
+ s->wrap == 2 ? GZIP_STATE :
+#endif
+ INIT_STATE;
+ strm->adler =
+#ifdef GZIP
+ s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
+#endif
+ adler32(0L, Z_NULL, 0);
+ s->last_flush = -2;
+
+ _tr_init(s);
+
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateReset(strm)
+ z_streamp strm;
+{
+ int ret;
+
+ ret = deflateResetKeep(strm);
+ if (ret == Z_OK)
+ lm_init(strm->state);
+ return ret;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateSetHeader(strm, head)
+ z_streamp strm;
+ gz_headerp head;
+{
+ if (deflateStateCheck(strm) || strm->state->wrap != 2)
+ return Z_STREAM_ERROR;
+ strm->state->gzhead = head;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflatePending(strm, pending, bits)
+ unsigned *pending;
+ int *bits;
+ z_streamp strm;
+{
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ if (pending != Z_NULL)
+ *pending = strm->state->pending;
+ if (bits != Z_NULL)
+ *bits = strm->state->bi_valid;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflatePrime(strm, bits, value)
+ z_streamp strm;
+ int bits;
+ int value;
+{
+ deflate_state *s;
+ int put;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ s = strm->state;
+ if (bits < 0 || bits > 16 ||
+ s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
+ return Z_BUF_ERROR;
+ do {
+ put = Buf_size - s->bi_valid;
+ if (put > bits)
+ put = bits;
+ s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
+ s->bi_valid += put;
+ _tr_flush_bits(s);
+ value >>= put;
+ bits -= put;
+ } while (bits);
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateParams(strm, level, strategy)
+ z_streamp strm;
+ int level;
+ int strategy;
+{
+ deflate_state *s;
+ compress_func func;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ s = strm->state;
+
+#ifdef FASTEST
+ if (level != 0) level = 1;
+#else
+ if (level == Z_DEFAULT_COMPRESSION) level = 6;
+#endif
+ if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
+ return Z_STREAM_ERROR;
+ }
+ func = configuration_table[s->level].func;
+
+ if ((strategy != s->strategy || func != configuration_table[level].func) &&
+ s->last_flush != -2) {
+ /* Flush the last buffer: */
+ int err = deflate(strm, Z_BLOCK);
+ if (err == Z_STREAM_ERROR)
+ return err;
+ if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead)
+ return Z_BUF_ERROR;
+ }
+ if (s->level != level) {
+ if (s->level == 0 && s->matches != 0) {
+ if (s->matches == 1)
+ slide_hash(s);
+ else
+ CLEAR_HASH(s);
+ s->matches = 0;
+ }
+ s->level = level;
+ s->max_lazy_match = configuration_table[level].max_lazy;
+ s->good_match = configuration_table[level].good_length;
+ s->nice_match = configuration_table[level].nice_length;
+ s->max_chain_length = configuration_table[level].max_chain;
+ }
+ s->strategy = strategy;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
+ z_streamp strm;
+ int good_length;
+ int max_lazy;
+ int nice_length;
+ int max_chain;
+{
+ deflate_state *s;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ s = strm->state;
+ s->good_match = (uInt)good_length;
+ s->max_lazy_match = (uInt)max_lazy;
+ s->nice_match = nice_length;
+ s->max_chain_length = (uInt)max_chain;
+ return Z_OK;
+}
+
+/* =========================================================================
+ * For the default windowBits of 15 and memLevel of 8, this function returns a
+ * close to exact, as well as small, upper bound on the compressed size. This
+ * is an expansion of ~0.03%, plus a small constant.
+ *
+ * For any setting other than those defaults for windowBits and memLevel, one
+ * of two worst case bounds is returned. This is at most an expansion of ~4% or
+ * ~13%, plus a small constant.
+ *
+ * Both the 0.03% and 4% derive from the overhead of stored blocks. The first
+ * one is for stored blocks of 16383 bytes (memLevel == 8), whereas the second
+ * is for stored blocks of 127 bytes (the worst case memLevel == 1). The
+ * expansion results from five bytes of header for each stored block.
+ *
+ * The larger expansion of 13% results from a window size less than or equal to
+ * the symbols buffer size (windowBits <= memLevel + 7). In that case some of
+ * the data being compressed may have slid out of the sliding window, impeding
+ * a stored block from being emitted. Then the only choice is a fixed or
+ * dynamic block, where a fixed block limits the maximum expansion to 9 bits
+ * per 8-bit byte, plus 10 bits for every block. The smallest block size for
+ * which this can occur is 255 (memLevel == 2).
+ *
+ * Shifts are used to approximate divisions, for speed.
+ */
+uLong ZEXPORT deflateBound(strm, sourceLen)
+ z_streamp strm;
+ uLong sourceLen;
+{
+ deflate_state *s;
+ uLong fixedlen, storelen, wraplen;
+
+ /* upper bound for fixed blocks with 9-bit literals and length 255
+ (memLevel == 2, which is the lowest that may not use stored blocks) --
+ ~13% overhead plus a small constant */
+ fixedlen = sourceLen + (sourceLen >> 3) + (sourceLen >> 8) +
+ (sourceLen >> 9) + 4;
+
+ /* upper bound for stored blocks with length 127 (memLevel == 1) --
+ ~4% overhead plus a small constant */
+ storelen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) +
+ (sourceLen >> 11) + 7;
+
+ /* if can't get parameters, return larger bound plus a zlib wrapper */
+ if (deflateStateCheck(strm))
+ return (fixedlen > storelen ? fixedlen : storelen) + 6;
+
+ /* compute wrapper length */
+ s = strm->state;
+ switch (s->wrap) {
+ case 0: /* raw deflate */
+ wraplen = 0;
+ break;
+ case 1: /* zlib wrapper */
+ wraplen = 6 + (s->strstart ? 4 : 0);
+ break;
+#ifdef GZIP
+ case 2: /* gzip wrapper */
+ wraplen = 18;
+ if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
+ Bytef *str;
+ if (s->gzhead->extra != Z_NULL)
+ wraplen += 2 + s->gzhead->extra_len;
+ str = s->gzhead->name;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ str = s->gzhead->comment;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ if (s->gzhead->hcrc)
+ wraplen += 2;
+ }
+ break;
+#endif
+ default: /* for compiler happiness */
+ wraplen = 6;
+ }
+
+ /* if not default parameters, return one of the conservative bounds */
+ if (s->w_bits != 15 || s->hash_bits != 8 + 7)
+ return (s->w_bits <= s->hash_bits ? fixedlen : storelen) + wraplen;
+
+ /* default settings: return tight bound for that case -- ~0.03% overhead
+ plus a small constant */
+ return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+ (sourceLen >> 25) + 13 - 6 + wraplen;
+}
+
+/* =========================================================================
+ * Put a short in the pending buffer. The 16-bit value is put in MSB order.
+ * IN assertion: the stream state is correct and there is enough room in
+ * pending_buf.
+ */
+local void putShortMSB(s, b)
+ deflate_state *s;
+ uInt b;
+{
+ put_byte(s, (Byte)(b >> 8));
+ put_byte(s, (Byte)(b & 0xff));
+}
+
+/* =========================================================================
+ * Flush as much pending output as possible. All deflate() output, except for
+ * some deflate_stored() output, goes through this function so some
+ * applications may wish to modify it to avoid allocating a large
+ * strm->next_out buffer and copying into it. (See also read_buf()).
+ */
+local void flush_pending(strm)
+ z_streamp strm;
+{
+ unsigned len;
+ deflate_state *s = strm->state;
+
+ _tr_flush_bits(s);
+ len = s->pending;
+ if (len > strm->avail_out) len = strm->avail_out;
+ if (len == 0) return;
+
+ zmemcpy(strm->next_out, s->pending_out, len);
+ strm->next_out += len;
+ s->pending_out += len;
+ strm->total_out += len;
+ strm->avail_out -= len;
+ s->pending -= len;
+ if (s->pending == 0) {
+ s->pending_out = s->pending_buf;
+ }
+}
+
+/* ===========================================================================
+ * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
+ */
+#define HCRC_UPDATE(beg) \
+ do { \
+ if (s->gzhead->hcrc && s->pending > (beg)) \
+ strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
+ s->pending - (beg)); \
+ } while (0)
+
+/* ========================================================================= */
+int ZEXPORT deflate(strm, flush)
+ z_streamp strm;
+ int flush;
+{
+ int old_flush; /* value of flush param for previous deflate call */
+ deflate_state *s;
+
+ if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
+ return Z_STREAM_ERROR;
+ }
+ s = strm->state;
+
+ if (strm->next_out == Z_NULL ||
+ (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
+ (s->status == FINISH_STATE && flush != Z_FINISH)) {
+ ERR_RETURN(strm, Z_STREAM_ERROR);
+ }
+ if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
+
+ old_flush = s->last_flush;
+ s->last_flush = flush;
+
+ /* Flush as much pending output as possible */
+ if (s->pending != 0) {
+ flush_pending(strm);
+ if (strm->avail_out == 0) {
+ /* Since avail_out is 0, deflate will be called again with
+ * more output space, but possibly with both pending and
+ * avail_in equal to zero. There won't be anything to do,
+ * but this is not an error situation so make sure we
+ * return OK instead of BUF_ERROR at next call of deflate:
+ */
+ s->last_flush = -1;
+ return Z_OK;
+ }
+
+ /* Make sure there is something to do and avoid duplicate consecutive
+ * flushes. For repeated and useless calls with Z_FINISH, we keep
+ * returning Z_STREAM_END instead of Z_BUF_ERROR.
+ */
+ } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
+ flush != Z_FINISH) {
+ ERR_RETURN(strm, Z_BUF_ERROR);
+ }
+
+ /* User must not provide more input after the first FINISH: */
+ if (s->status == FINISH_STATE && strm->avail_in != 0) {
+ ERR_RETURN(strm, Z_BUF_ERROR);
+ }
+
+ /* Write the header */
+ if (s->status == INIT_STATE && s->wrap == 0)
+ s->status = BUSY_STATE;
+ if (s->status == INIT_STATE) {
+ /* zlib header */
+ uInt header = (Z_DEFLATED + ((s->w_bits - 8) << 4)) << 8;
+ uInt level_flags;
+
+ if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
+ level_flags = 0;
+ else if (s->level < 6)
+ level_flags = 1;
+ else if (s->level == 6)
+ level_flags = 2;
+ else
+ level_flags = 3;
+ header |= (level_flags << 6);
+ if (s->strstart != 0) header |= PRESET_DICT;
+ header += 31 - (header % 31);
+
+ putShortMSB(s, header);
+
+ /* Save the adler32 of the preset dictionary: */
+ if (s->strstart != 0) {
+ putShortMSB(s, (uInt)(strm->adler >> 16));
+ putShortMSB(s, (uInt)(strm->adler & 0xffff));
+ }
+ strm->adler = adler32(0L, Z_NULL, 0);
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+#ifdef GZIP
+ if (s->status == GZIP_STATE) {
+ /* gzip header */
+ strm->adler = crc32(0L, Z_NULL, 0);
+ put_byte(s, 31);
+ put_byte(s, 139);
+ put_byte(s, 8);
+ if (s->gzhead == Z_NULL) {
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, s->level == 9 ? 2 :
+ (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+ 4 : 0));
+ put_byte(s, OS_CODE);
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+ else {
+ put_byte(s, (s->gzhead->text ? 1 : 0) +
+ (s->gzhead->hcrc ? 2 : 0) +
+ (s->gzhead->extra == Z_NULL ? 0 : 4) +
+ (s->gzhead->name == Z_NULL ? 0 : 8) +
+ (s->gzhead->comment == Z_NULL ? 0 : 16)
+ );
+ put_byte(s, (Byte)(s->gzhead->time & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
+ put_byte(s, s->level == 9 ? 2 :
+ (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+ 4 : 0));
+ put_byte(s, s->gzhead->os & 0xff);
+ if (s->gzhead->extra != Z_NULL) {
+ put_byte(s, s->gzhead->extra_len & 0xff);
+ put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
+ }
+ if (s->gzhead->hcrc)
+ strm->adler = crc32(strm->adler, s->pending_buf,
+ s->pending);
+ s->gzindex = 0;
+ s->status = EXTRA_STATE;
+ }
+ }
+ if (s->status == EXTRA_STATE) {
+ if (s->gzhead->extra != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
+ while (s->pending + left > s->pending_buf_size) {
+ uInt copy = s->pending_buf_size - s->pending;
+ zmemcpy(s->pending_buf + s->pending,
+ s->gzhead->extra + s->gzindex, copy);
+ s->pending = s->pending_buf_size;
+ HCRC_UPDATE(beg);
+ s->gzindex += copy;
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ left -= copy;
+ }
+ zmemcpy(s->pending_buf + s->pending,
+ s->gzhead->extra + s->gzindex, left);
+ s->pending += left;
+ HCRC_UPDATE(beg);
+ s->gzindex = 0;
+ }
+ s->status = NAME_STATE;
+ }
+ if (s->status == NAME_STATE) {
+ if (s->gzhead->name != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ int val;
+ do {
+ if (s->pending == s->pending_buf_size) {
+ HCRC_UPDATE(beg);
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ }
+ val = s->gzhead->name[s->gzindex++];
+ put_byte(s, val);
+ } while (val != 0);
+ HCRC_UPDATE(beg);
+ s->gzindex = 0;
+ }
+ s->status = COMMENT_STATE;
+ }
+ if (s->status == COMMENT_STATE) {
+ if (s->gzhead->comment != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ int val;
+ do {
+ if (s->pending == s->pending_buf_size) {
+ HCRC_UPDATE(beg);
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ }
+ val = s->gzhead->comment[s->gzindex++];
+ put_byte(s, val);
+ } while (val != 0);
+ HCRC_UPDATE(beg);
+ }
+ s->status = HCRC_STATE;
+ }
+ if (s->status == HCRC_STATE) {
+ if (s->gzhead->hcrc) {
+ if (s->pending + 2 > s->pending_buf_size) {
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+ put_byte(s, (Byte)(strm->adler & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
+ strm->adler = crc32(0L, Z_NULL, 0);
+ }
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+#endif
+
+ /* Start a new block or continue the current one.
+ */
+ if (strm->avail_in != 0 || s->lookahead != 0 ||
+ (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
+ block_state bstate;
+
+ bstate = s->level == 0 ? deflate_stored(s, flush) :
+ s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
+ s->strategy == Z_RLE ? deflate_rle(s, flush) :
+ (*(configuration_table[s->level].func))(s, flush);
+
+ if (bstate == finish_started || bstate == finish_done) {
+ s->status = FINISH_STATE;
+ }
+ if (bstate == need_more || bstate == finish_started) {
+ if (strm->avail_out == 0) {
+ s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
+ }
+ return Z_OK;
+ /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
+ * of deflate should use the same flush parameter to make sure
+ * that the flush is complete. So we don't have to output an
+ * empty block here, this will be done at next call. This also
+ * ensures that for a very small output buffer, we emit at most
+ * one empty block.
+ */
+ }
+ if (bstate == block_done) {
+ if (flush == Z_PARTIAL_FLUSH) {
+ _tr_align(s);
+ } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
+ _tr_stored_block(s, (char*)0, 0L, 0);
+ /* For a full flush, this empty block will be recognized
+ * as a special marker by inflate_sync().
+ */
+ if (flush == Z_FULL_FLUSH) {
+ CLEAR_HASH(s); /* forget history */
+ if (s->lookahead == 0) {
+ s->strstart = 0;
+ s->block_start = 0L;
+ s->insert = 0;
+ }
+ }
+ }
+ flush_pending(strm);
+ if (strm->avail_out == 0) {
+ s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
+ return Z_OK;
+ }
+ }
+ }
+
+ if (flush != Z_FINISH) return Z_OK;
+ if (s->wrap <= 0) return Z_STREAM_END;
+
+ /* Write the trailer */
+#ifdef GZIP
+ if (s->wrap == 2) {
+ put_byte(s, (Byte)(strm->adler & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
+ put_byte(s, (Byte)(strm->total_in & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
+ }
+ else
+#endif
+ {
+ putShortMSB(s, (uInt)(strm->adler >> 16));
+ putShortMSB(s, (uInt)(strm->adler & 0xffff));
+ }
+ flush_pending(strm);
+ /* If avail_out is zero, the application will call deflate again
+ * to flush the rest.
+ */
+ if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
+ return s->pending != 0 ? Z_OK : Z_STREAM_END;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateEnd(strm)
+ z_streamp strm;
+{
+ int status;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+
+ status = strm->state->status;
+
+ /* Deallocate in reverse order of allocations: */
+ TRY_FREE(strm, strm->state->pending_buf);
+ TRY_FREE(strm, strm->state->head);
+ TRY_FREE(strm, strm->state->prev);
+ TRY_FREE(strm, strm->state->window);
+
+ ZFREE(strm, strm->state);
+ strm->state = Z_NULL;
+
+ return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
+}
+
+/* =========================================================================
+ * Copy the source state to the destination state.
+ * To simplify the source, this is not supported for 16-bit MSDOS (which
+ * doesn't have enough memory anyway to duplicate compression states).
+ */
+int ZEXPORT deflateCopy(dest, source)
+ z_streamp dest;
+ z_streamp source;
+{
+#ifdef MAXSEG_64K
+ return Z_STREAM_ERROR;
+#else
+ deflate_state *ds;
+ deflate_state *ss;
+
+
+ if (deflateStateCheck(source) || dest == Z_NULL) {
+ return Z_STREAM_ERROR;
+ }
+
+ ss = source->state;
+
+ zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
+
+ ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
+ if (ds == Z_NULL) return Z_MEM_ERROR;
+ dest->state = (struct internal_state FAR *) ds;
+ zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
+ ds->strm = dest;
+
+ ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
+ ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
+ ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
+ ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4);
+
+ if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
+ ds->pending_buf == Z_NULL) {
+ deflateEnd (dest);
+ return Z_MEM_ERROR;
+ }
+ /* following zmemcpy do not work for 16-bit MSDOS */
+ zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
+ zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
+ zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
+ zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
+
+ ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
+ ds->sym_buf = ds->pending_buf + ds->lit_bufsize;
+
+ ds->l_desc.dyn_tree = ds->dyn_ltree;
+ ds->d_desc.dyn_tree = ds->dyn_dtree;
+ ds->bl_desc.dyn_tree = ds->bl_tree;
+
+ return Z_OK;
+#endif /* MAXSEG_64K */
+}
+
+/* ===========================================================================
+ * Read a new buffer from the current input stream, update the adler32
+ * and total number of bytes read. All deflate() input goes through
+ * this function so some applications may wish to modify it to avoid
+ * allocating a large strm->next_in buffer and copying from it.
+ * (See also flush_pending()).
+ */
+local unsigned read_buf(strm, buf, size)
+ z_streamp strm;
+ Bytef *buf;
+ unsigned size;
+{
+ unsigned len = strm->avail_in;
+
+ if (len > size) len = size;
+ if (len == 0) return 0;
+
+ strm->avail_in -= len;
+
+ zmemcpy(buf, strm->next_in, len);
+ if (strm->state->wrap == 1) {
+ strm->adler = adler32(strm->adler, buf, len);
+ }
+#ifdef GZIP
+ else if (strm->state->wrap == 2) {
+ strm->adler = crc32(strm->adler, buf, len);
+ }
+#endif
+ strm->next_in += len;
+ strm->total_in += len;
+
+ return len;
+}
+
+/* ===========================================================================
+ * Initialize the "longest match" routines for a new zlib stream
+ */
+local void lm_init(s)
+ deflate_state *s;
+{
+ s->window_size = (ulg)2L*s->w_size;
+
+ CLEAR_HASH(s);
+
+ /* Set the default configuration parameters:
+ */
+ s->max_lazy_match = configuration_table[s->level].max_lazy;
+ s->good_match = configuration_table[s->level].good_length;
+ s->nice_match = configuration_table[s->level].nice_length;
+ s->max_chain_length = configuration_table[s->level].max_chain;
+
+ s->strstart = 0;
+ s->block_start = 0L;
+ s->lookahead = 0;
+ s->insert = 0;
+ s->match_length = s->prev_length = MIN_MATCH-1;
+ s->match_available = 0;
+ s->ins_h = 0;
+}
+
+#ifndef FASTEST
+/* ===========================================================================
+ * Set match_start to the longest match starting at the given string and
+ * return its length. Matches shorter or equal to prev_length are discarded,
+ * in which case the result is equal to prev_length and match_start is
+ * garbage.
+ * IN assertions: cur_match is the head of the hash chain for the current
+ * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
+ * OUT assertion: the match length is not greater than s->lookahead.
+ */
+local uInt longest_match(s, cur_match)
+ deflate_state *s;
+ IPos cur_match; /* current match */
+{
+ unsigned chain_length = s->max_chain_length;/* max hash chain length */
+ register Bytef *scan = s->window + s->strstart; /* current string */
+ register Bytef *match; /* matched string */
+ register int len; /* length of current match */
+ int best_len = (int)s->prev_length; /* best match length so far */
+ int nice_match = s->nice_match; /* stop if match long enough */
+ IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
+ s->strstart - (IPos)MAX_DIST(s) : NIL;
+ /* Stop when cur_match becomes <= limit. To simplify the code,
+ * we prevent matches with the string of window index 0.
+ */
+ Posf *prev = s->prev;
+ uInt wmask = s->w_mask;
+
+#ifdef UNALIGNED_OK
+ /* Compare two bytes at a time. Note: this is not always beneficial.
+ * Try with and without -DUNALIGNED_OK to check.
+ */
+ register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
+ register ush scan_start = *(ushf*)scan;
+ register ush scan_end = *(ushf*)(scan + best_len - 1);
+#else
+ register Bytef *strend = s->window + s->strstart + MAX_MATCH;
+ register Byte scan_end1 = scan[best_len - 1];
+ register Byte scan_end = scan[best_len];
+#endif
+
+ /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
+ * It is easy to get rid of this optimization if necessary.
+ */
+ Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
+
+ /* Do not waste too much time if we already have a good match: */
+ if (s->prev_length >= s->good_match) {
+ chain_length >>= 2;
+ }
+ /* Do not look for matches beyond the end of the input. This is necessary
+ * to make deflate deterministic.
+ */
+ if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;
+
+ Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+ "need lookahead");
+
+ do {
+ Assert(cur_match < s->strstart, "no future");
+ match = s->window + cur_match;
+
+ /* Skip to next match if the match length cannot increase
+ * or if the match length is less than 2. Note that the checks below
+ * for insufficient lookahead only occur occasionally for performance
+ * reasons. Therefore uninitialized memory will be accessed, and
+ * conditional jumps will be made that depend on those values.
+ * However the length of the match is limited to the lookahead, so
+ * the output of deflate is not affected by the uninitialized values.
+ */
+#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
+ /* This code assumes sizeof(unsigned short) == 2. Do not use
+ * UNALIGNED_OK if your compiler uses a different size.
+ */
+ if (*(ushf*)(match + best_len - 1) != scan_end ||
+ *(ushf*)match != scan_start) continue;
+
+ /* It is not necessary to compare scan[2] and match[2] since they are
+ * always equal when the other bytes match, given that the hash keys
+ * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
+ * strstart + 3, + 5, up to strstart + 257. We check for insufficient
+ * lookahead only every 4th comparison; the 128th check will be made
+ * at strstart + 257. If MAX_MATCH-2 is not a multiple of 8, it is
+ * necessary to put more guard bytes at the end of the window, or
+ * to check more often for insufficient lookahead.
+ */
+ Assert(scan[2] == match[2], "scan[2]?");
+ scan++, match++;
+ do {
+ } while (*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
+ *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
+ *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
+ *(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
+ scan < strend);
+ /* The funny "do {}" generates better code on most compilers */
+
+ /* Here, scan <= window + strstart + 257 */
+ Assert(scan <= s->window + (unsigned)(s->window_size - 1),
+ "wild scan");
+ if (*scan == *match) scan++;
+
+ len = (MAX_MATCH - 1) - (int)(strend - scan);
+ scan = strend - (MAX_MATCH-1);
+
+#else /* UNALIGNED_OK */
+
+ if (match[best_len] != scan_end ||
+ match[best_len - 1] != scan_end1 ||
+ *match != *scan ||
+ *++match != scan[1]) continue;
+
+ /* The check at best_len - 1 can be removed because it will be made
+ * again later. (This heuristic is not always a win.)
+ * It is not necessary to compare scan[2] and match[2] since they
+ * are always equal when the other bytes match, given that
+ * the hash keys are equal and that HASH_BITS >= 8.
+ */
+ scan += 2, match++;
+ Assert(*scan == *match, "match[2]?");
+
+ /* We check for insufficient lookahead only every 8th comparison;
+ * the 256th check will be made at strstart + 258.
+ */
+ do {
+ } while (*++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ scan < strend);
+
+ Assert(scan <= s->window + (unsigned)(s->window_size - 1),
+ "wild scan");
+
+ len = MAX_MATCH - (int)(strend - scan);
+ scan = strend - MAX_MATCH;
+
+#endif /* UNALIGNED_OK */
+
+ if (len > best_len) {
+ s->match_start = cur_match;
+ best_len = len;
+ if (len >= nice_match) break;
+#ifdef UNALIGNED_OK
+ scan_end = *(ushf*)(scan + best_len - 1);
+#else
+ scan_end1 = scan[best_len - 1];
+ scan_end = scan[best_len];
+#endif
+ }
+ } while ((cur_match = prev[cur_match & wmask]) > limit
+ && --chain_length != 0);
+
+ if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
+ return s->lookahead;
+}
+
+#else /* FASTEST */
+
+/* ---------------------------------------------------------------------------
+ * Optimized version for FASTEST only
+ */
+local uInt longest_match(s, cur_match)
+ deflate_state *s;
+ IPos cur_match; /* current match */
+{
+ register Bytef *scan = s->window + s->strstart; /* current string */
+ register Bytef *match; /* matched string */
+ register int len; /* length of current match */
+ register Bytef *strend = s->window + s->strstart + MAX_MATCH;
+
+ /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
+ * It is easy to get rid of this optimization if necessary.
+ */
+ Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
+
+ Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+ "need lookahead");
+
+ Assert(cur_match < s->strstart, "no future");
+
+ match = s->window + cur_match;
+
+ /* Return failure if the match length is less than 2:
+ */
+ if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
+
+ /* The check at best_len - 1 can be removed because it will be made
+ * again later. (This heuristic is not always a win.)
+ * It is not necessary to compare scan[2] and match[2] since they
+ * are always equal when the other bytes match, given that
+ * the hash keys are equal and that HASH_BITS >= 8.
+ */
+ scan += 2, match += 2;
+ Assert(*scan == *match, "match[2]?");
+
+ /* We check for insufficient lookahead only every 8th comparison;
+ * the 256th check will be made at strstart + 258.
+ */
+ do {
+ } while (*++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ *++scan == *++match && *++scan == *++match &&
+ scan < strend);
+
+ Assert(scan <= s->window + (unsigned)(s->window_size - 1), "wild scan");
+
+ len = MAX_MATCH - (int)(strend - scan);
+
+ if (len < MIN_MATCH) return MIN_MATCH - 1;
+
+ s->match_start = cur_match;
+ return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
+}
+
+#endif /* FASTEST */
+
+#ifdef ZLIB_DEBUG
+
+#define EQUAL 0
+/* result of memcmp for equal strings */
+
+/* ===========================================================================
+ * Check that the match at match_start is indeed a match.
+ */
+local void check_match(s, start, match, length)
+ deflate_state *s;
+ IPos start, match;
+ int length;
+{
+ /* check that the match is indeed a match */
+ if (zmemcmp(s->window + match,
+ s->window + start, length) != EQUAL) {
+ fprintf(stderr, " start %u, match %u, length %d\n",
+ start, match, length);
+ do {
+ fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
+ } while (--length != 0);
+ z_error("invalid match");
+ }
+ if (z_verbose > 1) {
+ fprintf(stderr,"\\[%d,%d]", start - match, length);
+ do { putc(s->window[start++], stderr); } while (--length != 0);
+ }
+}
+#else
+# define check_match(s, start, match, length)
+#endif /* ZLIB_DEBUG */
+
+/* ===========================================================================
+ * Fill the window when the lookahead becomes insufficient.
+ * Updates strstart and lookahead.
+ *
+ * IN assertion: lookahead < MIN_LOOKAHEAD
+ * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
+ * At least one byte has been read, or avail_in == 0; reads are
+ * performed for at least two bytes (required for the zip translate_eol
+ * option -- not supported here).
+ */
+local void fill_window(s)
+ deflate_state *s;
+{
+ unsigned n;
+ unsigned more; /* Amount of free space at the end of the window. */
+ uInt wsize = s->w_size;
+
+ Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
+
+ do {
+ more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
+
+ /* Deal with !@#$% 64K limit: */
+ if (sizeof(int) <= 2) {
+ if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
+ more = wsize;
+
+ } else if (more == (unsigned)(-1)) {
+ /* Very unlikely, but possible on 16 bit machine if
+ * strstart == 0 && lookahead == 1 (input done a byte at time)
+ */
+ more--;
+ }
+ }
+
+ /* If the window is almost full and there is insufficient lookahead,
+ * move the upper half to the lower one to make room in the upper half.
+ */
+ if (s->strstart >= wsize + MAX_DIST(s)) {
+
+ zmemcpy(s->window, s->window + wsize, (unsigned)wsize - more);
+ s->match_start -= wsize;
+ s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
+ s->block_start -= (long) wsize;
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
+ slide_hash(s);
+ more += wsize;
+ }
+ if (s->strm->avail_in == 0) break;
+
+ /* If there was no sliding:
+ * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
+ * more == window_size - lookahead - strstart
+ * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
+ * => more >= window_size - 2*WSIZE + 2
+ * In the BIG_MEM or MMAP case (not yet supported),
+ * window_size == input_size + MIN_LOOKAHEAD &&
+ * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
+ * Otherwise, window_size == 2*WSIZE so more >= 2.
+ * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
+ */
+ Assert(more >= 2, "more < 2");
+
+ n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
+ s->lookahead += n;
+
+ /* Initialize the hash value now that we have some input: */
+ if (s->lookahead + s->insert >= MIN_MATCH) {
+ uInt str = s->strstart - s->insert;
+ s->ins_h = s->window[str];
+ UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
+#if MIN_MATCH != 3
+ Call UPDATE_HASH() MIN_MATCH-3 more times
+#endif
+ while (s->insert) {
+ UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+ s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+ s->head[s->ins_h] = (Pos)str;
+ str++;
+ s->insert--;
+ if (s->lookahead + s->insert < MIN_MATCH)
+ break;
+ }
+ }
+ /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
+ * but this is not important since only literal bytes will be emitted.
+ */
+
+ } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
+
+ /* If the WIN_INIT bytes after the end of the current data have never been
+ * written, then zero those bytes in order to avoid memory check reports of
+ * the use of uninitialized (or uninitialised as Julian writes) bytes by
+ * the longest match routines. Update the high water mark for the next
+ * time through here. WIN_INIT is set to MAX_MATCH since the longest match
+ * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+ */
+ if (s->high_water < s->window_size) {
+ ulg curr = s->strstart + (ulg)(s->lookahead);
+ ulg init;
+
+ if (s->high_water < curr) {
+ /* Previous high water mark below current data -- zero WIN_INIT
+ * bytes or up to end of window, whichever is less.
+ */
+ init = s->window_size - curr;
+ if (init > WIN_INIT)
+ init = WIN_INIT;
+ zmemzero(s->window + curr, (unsigned)init);
+ s->high_water = curr + init;
+ }
+ else if (s->high_water < (ulg)curr + WIN_INIT) {
+ /* High water mark at or above current data, but below current data
+ * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+ * to end of window, whichever is less.
+ */
+ init = (ulg)curr + WIN_INIT - s->high_water;
+ if (init > s->window_size - s->high_water)
+ init = s->window_size - s->high_water;
+ zmemzero(s->window + s->high_water, (unsigned)init);
+ s->high_water += init;
+ }
+ }
+
+ Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+ "not enough room for search");
+}
+
+/* ===========================================================================
+ * Flush the current block, with given end-of-file flag.
+ * IN assertion: strstart is set to the end of the current match.
+ */
+#define FLUSH_BLOCK_ONLY(s, last) { \
+ _tr_flush_block(s, (s->block_start >= 0L ? \
+ (charf *)&s->window[(unsigned)s->block_start] : \
+ (charf *)Z_NULL), \
+ (ulg)((long)s->strstart - s->block_start), \
+ (last)); \
+ s->block_start = s->strstart; \
+ flush_pending(s->strm); \
+ Tracev((stderr,"[FLUSH]")); \
+}
+
+/* Same but force premature exit if necessary. */
+#define FLUSH_BLOCK(s, last) { \
+ FLUSH_BLOCK_ONLY(s, last); \
+ if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
+}
+
+/* Maximum stored block length in deflate format (not including header). */
+#define MAX_STORED 65535
+
+/* Minimum of a and b. */
+#define MIN(a, b) ((a) > (b) ? (b) : (a))
+
+/* ===========================================================================
+ * Copy without compression as much as possible from the input stream, return
+ * the current block state.
+ *
+ * In case deflateParams() is used to later switch to a non-zero compression
+ * level, s->matches (otherwise unused when storing) keeps track of the number
+ * of hash table slides to perform. If s->matches is 1, then one hash table
+ * slide will be done when switching. If s->matches is 2, the maximum value
+ * allowed here, then the hash table will be cleared, since two or more slides
+ * is the same as a clear.
+ *
+ * deflate_stored() is written to minimize the number of times an input byte is
+ * copied. It is most efficient with large input and output buffers, which
+ * maximizes the opportunities to have a single copy from next_in to next_out.
+ */
+local block_state deflate_stored(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ /* Smallest worthy block size when not flushing or finishing. By default
+ * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
+ * large input and output buffers, the stored block size will be larger.
+ */
+ unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);
+
+ /* Copy as many min_block or larger stored blocks directly to next_out as
+ * possible. If flushing, copy the remaining available input to next_out as
+ * stored blocks, if there is enough space.
+ */
+ unsigned len, left, have, last = 0;
+ unsigned used = s->strm->avail_in;
+ do {
+ /* Set len to the maximum size block that we can copy directly with the
+ * available input data and output space. Set left to how much of that
+ * would be copied from what's left in the window.
+ */
+ len = MAX_STORED; /* maximum deflate stored block length */
+ have = (s->bi_valid + 42) >> 3; /* number of header bytes */
+ if (s->strm->avail_out < have) /* need room for header */
+ break;
+ /* maximum stored block length that will fit in avail_out: */
+ have = s->strm->avail_out - have;
+ left = s->strstart - s->block_start; /* bytes left in window */
+ if (len > (ulg)left + s->strm->avail_in)
+ len = left + s->strm->avail_in; /* limit len to the input */
+ if (len > have)
+ len = have; /* limit len to the output */
+
+ /* If the stored block would be less than min_block in length, or if
+ * unable to copy all of the available input when flushing, then try
+ * copying to the window and the pending buffer instead. Also don't
+ * write an empty block when flushing -- deflate() does that.
+ */
+ if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
+ flush == Z_NO_FLUSH ||
+ len != left + s->strm->avail_in))
+ break;
+
+ /* Make a dummy stored block in pending to get the header bytes,
+ * including any pending bits. This also updates the debugging counts.
+ */
+ last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
+ _tr_stored_block(s, (char *)0, 0L, last);
+
+ /* Replace the lengths in the dummy stored block with len. */
+ s->pending_buf[s->pending - 4] = len;
+ s->pending_buf[s->pending - 3] = len >> 8;
+ s->pending_buf[s->pending - 2] = ~len;
+ s->pending_buf[s->pending - 1] = ~len >> 8;
+
+ /* Write the stored block header bytes. */
+ flush_pending(s->strm);
+
+#ifdef ZLIB_DEBUG
+ /* Update debugging counts for the data about to be copied. */
+ s->compressed_len += len << 3;
+ s->bits_sent += len << 3;
+#endif
+
+ /* Copy uncompressed bytes from the window to next_out. */
+ if (left) {
+ if (left > len)
+ left = len;
+ zmemcpy(s->strm->next_out, s->window + s->block_start, left);
+ s->strm->next_out += left;
+ s->strm->avail_out -= left;
+ s->strm->total_out += left;
+ s->block_start += left;
+ len -= left;
+ }
+
+ /* Copy uncompressed bytes directly from next_in to next_out, updating
+ * the check value.
+ */
+ if (len) {
+ read_buf(s->strm, s->strm->next_out, len);
+ s->strm->next_out += len;
+ s->strm->avail_out -= len;
+ s->strm->total_out += len;
+ }
+ } while (last == 0);
+
+ /* Update the sliding window with the last s->w_size bytes of the copied
+ * data, or append all of the copied data to the existing window if less
+ * than s->w_size bytes were copied. Also update the number of bytes to
+ * insert in the hash tables, in the event that deflateParams() switches to
+ * a non-zero compression level.
+ */
+ used -= s->strm->avail_in; /* number of input bytes directly copied */
+ if (used) {
+ /* If any input was used, then no unused input remains in the window,
+ * therefore s->block_start == s->strstart.
+ */
+ if (used >= s->w_size) { /* supplant the previous history */
+ s->matches = 2; /* clear hash */
+ zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
+ s->strstart = s->w_size;
+ s->insert = s->strstart;
+ }
+ else {
+ if (s->window_size - s->strstart <= used) {
+ /* Slide the window down. */
+ s->strstart -= s->w_size;
+ zmemcpy(s->window, s->window + s->w_size, s->strstart);
+ if (s->matches < 2)
+ s->matches++; /* add a pending slide_hash() */
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
+ }
+ zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
+ s->strstart += used;
+ s->insert += MIN(used, s->w_size - s->insert);
+ }
+ s->block_start = s->strstart;
+ }
+ if (s->high_water < s->strstart)
+ s->high_water = s->strstart;
+
+ /* If the last block was written to next_out, then done. */
+ if (last)
+ return finish_done;
+
+ /* If flushing and all input has been consumed, then done. */
+ if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
+ s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
+ return block_done;
+
+ /* Fill the window with any remaining input. */
+ have = s->window_size - s->strstart;
+ if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
+ /* Slide the window down. */
+ s->block_start -= s->w_size;
+ s->strstart -= s->w_size;
+ zmemcpy(s->window, s->window + s->w_size, s->strstart);
+ if (s->matches < 2)
+ s->matches++; /* add a pending slide_hash() */
+ have += s->w_size; /* more space now */
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
+ }
+ if (have > s->strm->avail_in)
+ have = s->strm->avail_in;
+ if (have) {
+ read_buf(s->strm, s->window + s->strstart, have);
+ s->strstart += have;
+ s->insert += MIN(have, s->w_size - s->insert);
+ }
+ if (s->high_water < s->strstart)
+ s->high_water = s->strstart;
+
+ /* There was not enough avail_out to write a complete worthy or flushed
+ * stored block to next_out. Write a stored block to pending instead, if we
+ * have enough input for a worthy block, or if flushing and there is enough
+ * room for the remaining input as a stored block in the pending buffer.
+ */
+ have = (s->bi_valid + 42) >> 3; /* number of header bytes */
+ /* maximum stored block length that will fit in pending: */
+ have = MIN(s->pending_buf_size - have, MAX_STORED);
+ min_block = MIN(have, s->w_size);
+ left = s->strstart - s->block_start;
+ if (left >= min_block ||
+ ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
+ s->strm->avail_in == 0 && left <= have)) {
+ len = MIN(left, have);
+ last = flush == Z_FINISH && s->strm->avail_in == 0 &&
+ len == left ? 1 : 0;
+ _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
+ s->block_start += len;
+ flush_pending(s->strm);
+ }
+
+ /* We've done all we can with the available input and output. */
+ return last ? finish_started : need_more;
+}
+
+/* ===========================================================================
+ * Compress as much as possible from the input stream, return the current
+ * block state.
+ * This function does not perform lazy evaluation of matches and inserts
+ * new strings in the dictionary only for unmatched strings or for short
+ * matches. It is used only for the fast compression options.
+ */
+local block_state deflate_fast(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ IPos hash_head; /* head of the hash chain */
+ int bflush; /* set if current block must be flushed */
+
+ for (;;) {
+ /* Make sure that we always have enough lookahead, except
+ * at the end of the input file. We need MAX_MATCH bytes
+ * for the next match, plus MIN_MATCH bytes to insert the
+ * string following the next match.
+ */
+ if (s->lookahead < MIN_LOOKAHEAD) {
+ fill_window(s);
+ if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
+ return need_more;
+ }
+ if (s->lookahead == 0) break; /* flush the current block */
+ }
+
+ /* Insert the string window[strstart .. strstart + 2] in the
+ * dictionary, and set hash_head to the head of the hash chain:
+ */
+ hash_head = NIL;
+ if (s->lookahead >= MIN_MATCH) {
+ INSERT_STRING(s, s->strstart, hash_head);
+ }
+
+ /* Find the longest match, discarding those <= prev_length.
+ * At this point we have always match_length < MIN_MATCH
+ */
+ if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
+ /* To simplify the code, we prevent matches with the string
+ * of window index 0 (in particular we have to avoid a match
+ * of the string with itself at the start of the input file).
+ */
+ s->match_length = longest_match (s, hash_head);
+ /* longest_match() sets match_start */
+ }
+ if (s->match_length >= MIN_MATCH) {
+ check_match(s, s->strstart, s->match_start, s->match_length);
+
+ _tr_tally_dist(s, s->strstart - s->match_start,
+ s->match_length - MIN_MATCH, bflush);
+
+ s->lookahead -= s->match_length;
+
+ /* Insert new strings in the hash table only if the match length
+ * is not too large. This saves time but degrades compression.
+ */
+#ifndef FASTEST
+ if (s->match_length <= s->max_insert_length &&
+ s->lookahead >= MIN_MATCH) {
+ s->match_length--; /* string at strstart already in table */
+ do {
+ s->strstart++;
+ INSERT_STRING(s, s->strstart, hash_head);
+ /* strstart never exceeds WSIZE-MAX_MATCH, so there are
+ * always MIN_MATCH bytes ahead.
+ */
+ } while (--s->match_length != 0);
+ s->strstart++;
+ } else
+#endif
+ {
+ s->strstart += s->match_length;
+ s->match_length = 0;
+ s->ins_h = s->window[s->strstart];
+ UPDATE_HASH(s, s->ins_h, s->window[s->strstart + 1]);
+#if MIN_MATCH != 3
+ Call UPDATE_HASH() MIN_MATCH-3 more times
+#endif
+ /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
+ * matter since it will be recomputed at next deflate call.
+ */
+ }
+ } else {
+ /* No match, output a literal byte */
+ Tracevv((stderr,"%c", s->window[s->strstart]));
+ _tr_tally_lit(s, s->window[s->strstart], bflush);
+ s->lookahead--;
+ s->strstart++;
+ }
+ if (bflush) FLUSH_BLOCK(s, 0);
+ }
+ s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
+
+#ifndef FASTEST
+/* ===========================================================================
+ * Same as above, but achieves better compression. We use a lazy
+ * evaluation for matches: a match is finally adopted only if there is
+ * no better match at the next window position.
+ */
+local block_state deflate_slow(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ IPos hash_head; /* head of hash chain */
+ int bflush; /* set if current block must be flushed */
+
+ /* Process the input block. */
+ for (;;) {
+ /* Make sure that we always have enough lookahead, except
+ * at the end of the input file. We need MAX_MATCH bytes
+ * for the next match, plus MIN_MATCH bytes to insert the
+ * string following the next match.
+ */
+ if (s->lookahead < MIN_LOOKAHEAD) {
+ fill_window(s);
+ if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
+ return need_more;
+ }
+ if (s->lookahead == 0) break; /* flush the current block */
+ }
+
+ /* Insert the string window[strstart .. strstart + 2] in the
+ * dictionary, and set hash_head to the head of the hash chain:
+ */
+ hash_head = NIL;
+ if (s->lookahead >= MIN_MATCH) {
+ INSERT_STRING(s, s->strstart, hash_head);
+ }
+
+ /* Find the longest match, discarding those <= prev_length.
+ */
+ s->prev_length = s->match_length, s->prev_match = s->match_start;
+ s->match_length = MIN_MATCH-1;
+
+ if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
+ s->strstart - hash_head <= MAX_DIST(s)) {
+ /* To simplify the code, we prevent matches with the string
+ * of window index 0 (in particular we have to avoid a match
+ * of the string with itself at the start of the input file).
+ */
+ s->match_length = longest_match (s, hash_head);
+ /* longest_match() sets match_start */
+
+ if (s->match_length <= 5 && (s->strategy == Z_FILTERED
+#if TOO_FAR <= 32767
+ || (s->match_length == MIN_MATCH &&
+ s->strstart - s->match_start > TOO_FAR)
+#endif
+ )) {
+
+ /* If prev_match is also MIN_MATCH, match_start is garbage
+ * but we will ignore the current match anyway.
+ */
+ s->match_length = MIN_MATCH-1;
+ }
+ }
+ /* If there was a match at the previous step and the current
+ * match is not better, output the previous match:
+ */
+ if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
+ uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
+ /* Do not insert strings in hash table beyond this. */
+
+ check_match(s, s->strstart - 1, s->prev_match, s->prev_length);
+
+ _tr_tally_dist(s, s->strstart - 1 - s->prev_match,
+ s->prev_length - MIN_MATCH, bflush);
+
+ /* Insert in hash table all strings up to the end of the match.
+ * strstart - 1 and strstart are already inserted. If there is not
+ * enough lookahead, the last two strings are not inserted in
+ * the hash table.
+ */
+ s->lookahead -= s->prev_length - 1;
+ s->prev_length -= 2;
+ do {
+ if (++s->strstart <= max_insert) {
+ INSERT_STRING(s, s->strstart, hash_head);
+ }
+ } while (--s->prev_length != 0);
+ s->match_available = 0;
+ s->match_length = MIN_MATCH-1;
+ s->strstart++;
+
+ if (bflush) FLUSH_BLOCK(s, 0);
+
+ } else if (s->match_available) {
+ /* If there was no match at the previous position, output a
+ * single literal. If there was a match but the current match
+ * is longer, truncate the previous match to a single literal.
+ */
+ Tracevv((stderr,"%c", s->window[s->strstart - 1]));
+ _tr_tally_lit(s, s->window[s->strstart - 1], bflush);
+ if (bflush) {
+ FLUSH_BLOCK_ONLY(s, 0);
+ }
+ s->strstart++;
+ s->lookahead--;
+ if (s->strm->avail_out == 0) return need_more;
+ } else {
+ /* There is no previous match to compare with, wait for
+ * the next step to decide.
+ */
+ s->match_available = 1;
+ s->strstart++;
+ s->lookahead--;
+ }
+ }
+ Assert (flush != Z_NO_FLUSH, "no flush?");
+ if (s->match_available) {
+ Tracevv((stderr,"%c", s->window[s->strstart - 1]));
+ _tr_tally_lit(s, s->window[s->strstart - 1], bflush);
+ s->match_available = 0;
+ }
+ s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
+#endif /* FASTEST */
+
+/* ===========================================================================
+ * For Z_RLE, simply look for runs of bytes, generate matches only of distance
+ * one. Do not maintain a hash table. (It will be regenerated if this run of
+ * deflate switches away from Z_RLE.)
+ */
+local block_state deflate_rle(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ int bflush; /* set if current block must be flushed */
+ uInt prev; /* byte at distance one to match */
+ Bytef *scan, *strend; /* scan goes up to strend for length of run */
+
+ for (;;) {
+ /* Make sure that we always have enough lookahead, except
+ * at the end of the input file. We need MAX_MATCH bytes
+ * for the longest run, plus one for the unrolled loop.
+ */
+ if (s->lookahead <= MAX_MATCH) {
+ fill_window(s);
+ if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
+ return need_more;
+ }
+ if (s->lookahead == 0) break; /* flush the current block */
+ }
+
+ /* See how many times the previous byte repeats */
+ s->match_length = 0;
+ if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
+ scan = s->window + s->strstart - 1;
+ prev = *scan;
+ if (prev == *++scan && prev == *++scan && prev == *++scan) {
+ strend = s->window + s->strstart + MAX_MATCH;
+ do {
+ } while (prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ scan < strend);
+ s->match_length = MAX_MATCH - (uInt)(strend - scan);
+ if (s->match_length > s->lookahead)
+ s->match_length = s->lookahead;
+ }
+ Assert(scan <= s->window + (uInt)(s->window_size - 1),
+ "wild scan");
+ }
+
+ /* Emit match if have run of MIN_MATCH or longer, else emit literal */
+ if (s->match_length >= MIN_MATCH) {
+ check_match(s, s->strstart, s->strstart - 1, s->match_length);
+
+ _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
+
+ s->lookahead -= s->match_length;
+ s->strstart += s->match_length;
+ s->match_length = 0;
+ } else {
+ /* No match, output a literal byte */
+ Tracevv((stderr,"%c", s->window[s->strstart]));
+ _tr_tally_lit(s, s->window[s->strstart], bflush);
+ s->lookahead--;
+ s->strstart++;
+ }
+ if (bflush) FLUSH_BLOCK(s, 0);
+ }
+ s->insert = 0;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
+
+/* ===========================================================================
+ * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
+ * (It will be regenerated if this run of deflate switches away from Huffman.)
+ */
+local block_state deflate_huff(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ int bflush; /* set if current block must be flushed */
+
+ for (;;) {
+ /* Make sure that we have a literal to write. */
+ if (s->lookahead == 0) {
+ fill_window(s);
+ if (s->lookahead == 0) {
+ if (flush == Z_NO_FLUSH)
+ return need_more;
+ break; /* flush the current block */
+ }
+ }
+
+ /* Output a literal byte */
+ s->match_length = 0;
+ Tracevv((stderr,"%c", s->window[s->strstart]));
+ _tr_tally_lit(s, s->window[s->strstart], bflush);
+ s->lookahead--;
+ s->strstart++;
+ if (bflush) FLUSH_BLOCK(s, 0);
+ }
+ s->insert = 0;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
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