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Diffstat (limited to 'modules/zlib/src/deflate.c')
| -rw-r--r-- | modules/zlib/src/deflate.c | 2217 |
1 files changed, 2217 insertions, 0 deletions
diff --git a/modules/zlib/src/deflate.c b/modules/zlib/src/deflate.c new file mode 100644 index 0000000000..4a689db359 --- /dev/null +++ b/modules/zlib/src/deflate.c @@ -0,0 +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 1.2.13 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; +} |