Chris@43: /* deflate.c -- compress data using the deflation algorithm Chris@43: * Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler Chris@43: * For conditions of distribution and use, see copyright notice in zlib.h Chris@43: */ Chris@43: Chris@43: /* Chris@43: * ALGORITHM Chris@43: * Chris@43: * The "deflation" process depends on being able to identify portions Chris@43: * of the input text which are identical to earlier input (within a Chris@43: * sliding window trailing behind the input currently being processed). Chris@43: * Chris@43: * The most straightforward technique turns out to be the fastest for Chris@43: * most input files: try all possible matches and select the longest. Chris@43: * The key feature of this algorithm is that insertions into the string Chris@43: * dictionary are very simple and thus fast, and deletions are avoided Chris@43: * completely. Insertions are performed at each input character, whereas Chris@43: * string matches are performed only when the previous match ends. So it Chris@43: * is preferable to spend more time in matches to allow very fast string Chris@43: * insertions and avoid deletions. The matching algorithm for small Chris@43: * strings is inspired from that of Rabin & Karp. A brute force approach Chris@43: * is used to find longer strings when a small match has been found. Chris@43: * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze Chris@43: * (by Leonid Broukhis). Chris@43: * A previous version of this file used a more sophisticated algorithm Chris@43: * (by Fiala and Greene) which is guaranteed to run in linear amortized Chris@43: * time, but has a larger average cost, uses more memory and is patented. Chris@43: * However the F&G algorithm may be faster for some highly redundant Chris@43: * files if the parameter max_chain_length (described below) is too large. Chris@43: * Chris@43: * ACKNOWLEDGEMENTS Chris@43: * Chris@43: * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and Chris@43: * I found it in 'freeze' written by Leonid Broukhis. Chris@43: * Thanks to many people for bug reports and testing. Chris@43: * Chris@43: * REFERENCES Chris@43: * Chris@43: * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". Chris@43: * Available in http://tools.ietf.org/html/rfc1951 Chris@43: * Chris@43: * A description of the Rabin and Karp algorithm is given in the book Chris@43: * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. Chris@43: * Chris@43: * Fiala,E.R., and Greene,D.H. Chris@43: * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 Chris@43: * Chris@43: */ Chris@43: Chris@43: /* @(#) $Id$ */ Chris@43: Chris@43: #include "deflate.h" Chris@43: Chris@43: const char deflate_copyright[] = Chris@43: " deflate 1.2.8 Copyright 1995-2013 Jean-loup Gailly and Mark Adler "; Chris@43: /* Chris@43: If you use the zlib library in a product, an acknowledgment is welcome Chris@43: in the documentation of your product. If for some reason you cannot Chris@43: include such an acknowledgment, I would appreciate that you keep this Chris@43: copyright string in the executable of your product. Chris@43: */ Chris@43: Chris@43: /* =========================================================================== Chris@43: * Function prototypes. Chris@43: */ Chris@43: typedef enum { Chris@43: need_more, /* block not completed, need more input or more output */ Chris@43: block_done, /* block flush performed */ Chris@43: finish_started, /* finish started, need only more output at next deflate */ Chris@43: finish_done /* finish done, accept no more input or output */ Chris@43: } block_state; Chris@43: Chris@43: typedef block_state (*compress_func) OF((deflate_state *s, int flush)); Chris@43: /* Compression function. Returns the block state after the call. */ Chris@43: Chris@43: local void fill_window OF((deflate_state *s)); Chris@43: local block_state deflate_stored OF((deflate_state *s, int flush)); Chris@43: local block_state deflate_fast OF((deflate_state *s, int flush)); Chris@43: #ifndef FASTEST Chris@43: local block_state deflate_slow OF((deflate_state *s, int flush)); Chris@43: #endif Chris@43: local block_state deflate_rle OF((deflate_state *s, int flush)); Chris@43: local block_state deflate_huff OF((deflate_state *s, int flush)); Chris@43: local void lm_init OF((deflate_state *s)); Chris@43: local void putShortMSB OF((deflate_state *s, uInt b)); Chris@43: local void flush_pending OF((z_streamp strm)); Chris@43: local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); Chris@43: #ifdef ASMV Chris@43: void match_init OF((void)); /* asm code initialization */ Chris@43: uInt longest_match OF((deflate_state *s, IPos cur_match)); Chris@43: #else Chris@43: local uInt longest_match OF((deflate_state *s, IPos cur_match)); Chris@43: #endif Chris@43: Chris@43: #ifdef DEBUG Chris@43: local void check_match OF((deflate_state *s, IPos start, IPos match, Chris@43: int length)); Chris@43: #endif Chris@43: Chris@43: /* =========================================================================== Chris@43: * Local data Chris@43: */ Chris@43: Chris@43: #define NIL 0 Chris@43: /* Tail of hash chains */ Chris@43: Chris@43: #ifndef TOO_FAR Chris@43: # define TOO_FAR 4096 Chris@43: #endif Chris@43: /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ Chris@43: Chris@43: /* Values for max_lazy_match, good_match and max_chain_length, depending on Chris@43: * the desired pack level (0..9). The values given below have been tuned to Chris@43: * exclude worst case performance for pathological files. Better values may be Chris@43: * found for specific files. Chris@43: */ Chris@43: typedef struct config_s { Chris@43: ush good_length; /* reduce lazy search above this match length */ Chris@43: ush max_lazy; /* do not perform lazy search above this match length */ Chris@43: ush nice_length; /* quit search above this match length */ Chris@43: ush max_chain; Chris@43: compress_func func; Chris@43: } config; Chris@43: Chris@43: #ifdef FASTEST Chris@43: local const config configuration_table[2] = { Chris@43: /* good lazy nice chain */ Chris@43: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ Chris@43: /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ Chris@43: #else Chris@43: local const config configuration_table[10] = { Chris@43: /* good lazy nice chain */ Chris@43: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ Chris@43: /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ Chris@43: /* 2 */ {4, 5, 16, 8, deflate_fast}, Chris@43: /* 3 */ {4, 6, 32, 32, deflate_fast}, Chris@43: Chris@43: /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ Chris@43: /* 5 */ {8, 16, 32, 32, deflate_slow}, Chris@43: /* 6 */ {8, 16, 128, 128, deflate_slow}, Chris@43: /* 7 */ {8, 32, 128, 256, deflate_slow}, Chris@43: /* 8 */ {32, 128, 258, 1024, deflate_slow}, Chris@43: /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ Chris@43: #endif Chris@43: Chris@43: /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 Chris@43: * For deflate_fast() (levels <= 3) good is ignored and lazy has a different Chris@43: * meaning. Chris@43: */ Chris@43: Chris@43: #define EQUAL 0 Chris@43: /* result of memcmp for equal strings */ Chris@43: Chris@43: #ifndef NO_DUMMY_DECL Chris@43: struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ Chris@43: #endif Chris@43: Chris@43: /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */ Chris@43: #define RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 0)) Chris@43: Chris@43: /* =========================================================================== Chris@43: * Update a hash value with the given input byte Chris@43: * IN assertion: all calls to to UPDATE_HASH are made with consecutive Chris@43: * input characters, so that a running hash key can be computed from the Chris@43: * previous key instead of complete recalculation each time. Chris@43: */ Chris@43: #define UPDATE_HASH(s,h,c) (h = (((h)<hash_shift) ^ (c)) & s->hash_mask) Chris@43: Chris@43: Chris@43: /* =========================================================================== Chris@43: * Insert string str in the dictionary and set match_head to the previous head Chris@43: * of the hash chain (the most recent string with same hash key). Return Chris@43: * the previous length of the hash chain. Chris@43: * If this file is compiled with -DFASTEST, the compression level is forced Chris@43: * to 1, and no hash chains are maintained. Chris@43: * IN assertion: all calls to to INSERT_STRING are made with consecutive Chris@43: * input characters and the first MIN_MATCH bytes of str are valid Chris@43: * (except for the last MIN_MATCH-1 bytes of the input file). Chris@43: */ Chris@43: #ifdef FASTEST Chris@43: #define INSERT_STRING(s, str, match_head) \ Chris@43: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ Chris@43: match_head = s->head[s->ins_h], \ Chris@43: s->head[s->ins_h] = (Pos)(str)) Chris@43: #else Chris@43: #define INSERT_STRING(s, str, match_head) \ Chris@43: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ Chris@43: match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ Chris@43: s->head[s->ins_h] = (Pos)(str)) Chris@43: #endif Chris@43: Chris@43: /* =========================================================================== Chris@43: * Initialize the hash table (avoiding 64K overflow for 16 bit systems). Chris@43: * prev[] will be initialized on the fly. Chris@43: */ Chris@43: #define CLEAR_HASH(s) \ Chris@43: s->head[s->hash_size-1] = NIL; \ Chris@43: zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateInit_(strm, level, version, stream_size) Chris@43: z_streamp strm; Chris@43: int level; Chris@43: const char *version; Chris@43: int stream_size; Chris@43: { Chris@43: return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Chris@43: Z_DEFAULT_STRATEGY, version, stream_size); Chris@43: /* To do: ignore strm->next_in if we use it as window */ Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, Chris@43: version, stream_size) Chris@43: z_streamp strm; Chris@43: int level; Chris@43: int method; Chris@43: int windowBits; Chris@43: int memLevel; Chris@43: int strategy; Chris@43: const char *version; Chris@43: int stream_size; Chris@43: { Chris@43: deflate_state *s; Chris@43: int wrap = 1; Chris@43: static const char my_version[] = ZLIB_VERSION; Chris@43: Chris@43: ushf *overlay; Chris@43: /* We overlay pending_buf and d_buf+l_buf. This works since the average Chris@43: * output size for (length,distance) codes is <= 24 bits. Chris@43: */ Chris@43: Chris@43: if (version == Z_NULL || version[0] != my_version[0] || Chris@43: stream_size != sizeof(z_stream)) { Chris@43: return Z_VERSION_ERROR; Chris@43: } Chris@43: if (strm == Z_NULL) return Z_STREAM_ERROR; Chris@43: Chris@43: strm->msg = Z_NULL; Chris@43: if (strm->zalloc == (alloc_func)0) { Chris@43: #ifdef Z_SOLO Chris@43: return Z_STREAM_ERROR; Chris@43: #else Chris@43: strm->zalloc = zcalloc; Chris@43: strm->opaque = (voidpf)0; Chris@43: #endif Chris@43: } Chris@43: if (strm->zfree == (free_func)0) Chris@43: #ifdef Z_SOLO Chris@43: return Z_STREAM_ERROR; Chris@43: #else Chris@43: strm->zfree = zcfree; Chris@43: #endif Chris@43: Chris@43: #ifdef FASTEST Chris@43: if (level != 0) level = 1; Chris@43: #else Chris@43: if (level == Z_DEFAULT_COMPRESSION) level = 6; Chris@43: #endif Chris@43: Chris@43: if (windowBits < 0) { /* suppress zlib wrapper */ Chris@43: wrap = 0; Chris@43: windowBits = -windowBits; Chris@43: } Chris@43: #ifdef GZIP Chris@43: else if (windowBits > 15) { Chris@43: wrap = 2; /* write gzip wrapper instead */ Chris@43: windowBits -= 16; Chris@43: } Chris@43: #endif Chris@43: if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || Chris@43: windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || Chris@43: strategy < 0 || strategy > Z_FIXED) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ Chris@43: s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); Chris@43: if (s == Z_NULL) return Z_MEM_ERROR; Chris@43: strm->state = (struct internal_state FAR *)s; Chris@43: s->strm = strm; Chris@43: Chris@43: s->wrap = wrap; Chris@43: s->gzhead = Z_NULL; Chris@43: s->w_bits = windowBits; Chris@43: s->w_size = 1 << s->w_bits; Chris@43: s->w_mask = s->w_size - 1; Chris@43: Chris@43: s->hash_bits = memLevel + 7; Chris@43: s->hash_size = 1 << s->hash_bits; Chris@43: s->hash_mask = s->hash_size - 1; Chris@43: s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); Chris@43: Chris@43: s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); Chris@43: s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); Chris@43: s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); Chris@43: Chris@43: s->high_water = 0; /* nothing written to s->window yet */ Chris@43: Chris@43: s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ Chris@43: Chris@43: overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); Chris@43: s->pending_buf = (uchf *) overlay; Chris@43: s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); Chris@43: Chris@43: if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || Chris@43: s->pending_buf == Z_NULL) { Chris@43: s->status = FINISH_STATE; Chris@43: strm->msg = ERR_MSG(Z_MEM_ERROR); Chris@43: deflateEnd (strm); Chris@43: return Z_MEM_ERROR; Chris@43: } Chris@43: s->d_buf = overlay + s->lit_bufsize/sizeof(ush); Chris@43: s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; Chris@43: Chris@43: s->level = level; Chris@43: s->strategy = strategy; Chris@43: s->method = (Byte)method; Chris@43: Chris@43: return deflateReset(strm); Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) Chris@43: z_streamp strm; Chris@43: const Bytef *dictionary; Chris@43: uInt dictLength; Chris@43: { Chris@43: deflate_state *s; Chris@43: uInt str, n; Chris@43: int wrap; Chris@43: unsigned avail; Chris@43: z_const unsigned char *next; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL) Chris@43: return Z_STREAM_ERROR; Chris@43: s = strm->state; Chris@43: wrap = s->wrap; Chris@43: if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) Chris@43: return Z_STREAM_ERROR; Chris@43: Chris@43: /* when using zlib wrappers, compute Adler-32 for provided dictionary */ Chris@43: if (wrap == 1) Chris@43: strm->adler = adler32(strm->adler, dictionary, dictLength); Chris@43: s->wrap = 0; /* avoid computing Adler-32 in read_buf */ Chris@43: Chris@43: /* if dictionary would fill window, just replace the history */ Chris@43: if (dictLength >= s->w_size) { Chris@43: if (wrap == 0) { /* already empty otherwise */ Chris@43: CLEAR_HASH(s); Chris@43: s->strstart = 0; Chris@43: s->block_start = 0L; Chris@43: s->insert = 0; Chris@43: } Chris@43: dictionary += dictLength - s->w_size; /* use the tail */ Chris@43: dictLength = s->w_size; Chris@43: } Chris@43: Chris@43: /* insert dictionary into window and hash */ Chris@43: avail = strm->avail_in; Chris@43: next = strm->next_in; Chris@43: strm->avail_in = dictLength; Chris@43: strm->next_in = (z_const Bytef *)dictionary; Chris@43: fill_window(s); Chris@43: while (s->lookahead >= MIN_MATCH) { Chris@43: str = s->strstart; Chris@43: n = s->lookahead - (MIN_MATCH-1); Chris@43: do { Chris@43: UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); Chris@43: #ifndef FASTEST Chris@43: s->prev[str & s->w_mask] = s->head[s->ins_h]; Chris@43: #endif Chris@43: s->head[s->ins_h] = (Pos)str; Chris@43: str++; Chris@43: } while (--n); Chris@43: s->strstart = str; Chris@43: s->lookahead = MIN_MATCH-1; Chris@43: fill_window(s); Chris@43: } Chris@43: s->strstart += s->lookahead; Chris@43: s->block_start = (long)s->strstart; Chris@43: s->insert = s->lookahead; Chris@43: s->lookahead = 0; Chris@43: s->match_length = s->prev_length = MIN_MATCH-1; Chris@43: s->match_available = 0; Chris@43: strm->next_in = next; Chris@43: strm->avail_in = avail; Chris@43: s->wrap = wrap; Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateResetKeep (strm) Chris@43: z_streamp strm; Chris@43: { Chris@43: deflate_state *s; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL || Chris@43: strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: Chris@43: strm->total_in = strm->total_out = 0; Chris@43: strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ Chris@43: strm->data_type = Z_UNKNOWN; Chris@43: Chris@43: s = (deflate_state *)strm->state; Chris@43: s->pending = 0; Chris@43: s->pending_out = s->pending_buf; Chris@43: Chris@43: if (s->wrap < 0) { Chris@43: s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ Chris@43: } Chris@43: s->status = s->wrap ? INIT_STATE : BUSY_STATE; Chris@43: strm->adler = Chris@43: #ifdef GZIP Chris@43: s->wrap == 2 ? crc32(0L, Z_NULL, 0) : Chris@43: #endif Chris@43: adler32(0L, Z_NULL, 0); Chris@43: s->last_flush = Z_NO_FLUSH; Chris@43: Chris@43: _tr_init(s); Chris@43: Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateReset (strm) Chris@43: z_streamp strm; Chris@43: { Chris@43: int ret; Chris@43: Chris@43: ret = deflateResetKeep(strm); Chris@43: if (ret == Z_OK) Chris@43: lm_init(strm->state); Chris@43: return ret; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateSetHeader (strm, head) Chris@43: z_streamp strm; Chris@43: gz_headerp head; Chris@43: { Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: if (strm->state->wrap != 2) return Z_STREAM_ERROR; Chris@43: strm->state->gzhead = head; Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflatePending (strm, pending, bits) Chris@43: unsigned *pending; Chris@43: int *bits; Chris@43: z_streamp strm; Chris@43: { Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: if (pending != Z_NULL) Chris@43: *pending = strm->state->pending; Chris@43: if (bits != Z_NULL) Chris@43: *bits = strm->state->bi_valid; Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflatePrime (strm, bits, value) Chris@43: z_streamp strm; Chris@43: int bits; Chris@43: int value; Chris@43: { Chris@43: deflate_state *s; Chris@43: int put; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: s = strm->state; Chris@43: if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3)) Chris@43: return Z_BUF_ERROR; Chris@43: do { Chris@43: put = Buf_size - s->bi_valid; Chris@43: if (put > bits) Chris@43: put = bits; Chris@43: s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); Chris@43: s->bi_valid += put; Chris@43: _tr_flush_bits(s); Chris@43: value >>= put; Chris@43: bits -= put; Chris@43: } while (bits); Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateParams(strm, level, strategy) Chris@43: z_streamp strm; Chris@43: int level; Chris@43: int strategy; Chris@43: { Chris@43: deflate_state *s; Chris@43: compress_func func; Chris@43: int err = Z_OK; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: s = strm->state; Chris@43: Chris@43: #ifdef FASTEST Chris@43: if (level != 0) level = 1; Chris@43: #else Chris@43: if (level == Z_DEFAULT_COMPRESSION) level = 6; Chris@43: #endif Chris@43: if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: func = configuration_table[s->level].func; Chris@43: Chris@43: if ((strategy != s->strategy || func != configuration_table[level].func) && Chris@43: strm->total_in != 0) { Chris@43: /* Flush the last buffer: */ Chris@43: err = deflate(strm, Z_BLOCK); Chris@43: if (err == Z_BUF_ERROR && s->pending == 0) Chris@43: err = Z_OK; Chris@43: } Chris@43: if (s->level != level) { Chris@43: s->level = level; Chris@43: s->max_lazy_match = configuration_table[level].max_lazy; Chris@43: s->good_match = configuration_table[level].good_length; Chris@43: s->nice_match = configuration_table[level].nice_length; Chris@43: s->max_chain_length = configuration_table[level].max_chain; Chris@43: } Chris@43: s->strategy = strategy; Chris@43: return err; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) Chris@43: z_streamp strm; Chris@43: int good_length; Chris@43: int max_lazy; Chris@43: int nice_length; Chris@43: int max_chain; Chris@43: { Chris@43: deflate_state *s; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: s = strm->state; Chris@43: s->good_match = good_length; Chris@43: s->max_lazy_match = max_lazy; Chris@43: s->nice_match = nice_length; Chris@43: s->max_chain_length = max_chain; Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= Chris@43: * For the default windowBits of 15 and memLevel of 8, this function returns Chris@43: * a close to exact, as well as small, upper bound on the compressed size. Chris@43: * They are coded as constants here for a reason--if the #define's are Chris@43: * changed, then this function needs to be changed as well. The return Chris@43: * value for 15 and 8 only works for those exact settings. Chris@43: * Chris@43: * For any setting other than those defaults for windowBits and memLevel, Chris@43: * the value returned is a conservative worst case for the maximum expansion Chris@43: * resulting from using fixed blocks instead of stored blocks, which deflate Chris@43: * can emit on compressed data for some combinations of the parameters. Chris@43: * Chris@43: * This function could be more sophisticated to provide closer upper bounds for Chris@43: * every combination of windowBits and memLevel. But even the conservative Chris@43: * upper bound of about 14% expansion does not seem onerous for output buffer Chris@43: * allocation. Chris@43: */ Chris@43: uLong ZEXPORT deflateBound(strm, sourceLen) Chris@43: z_streamp strm; Chris@43: uLong sourceLen; Chris@43: { Chris@43: deflate_state *s; Chris@43: uLong complen, wraplen; Chris@43: Bytef *str; Chris@43: Chris@43: /* conservative upper bound for compressed data */ Chris@43: complen = sourceLen + Chris@43: ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; Chris@43: Chris@43: /* if can't get parameters, return conservative bound plus zlib wrapper */ Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) Chris@43: return complen + 6; Chris@43: Chris@43: /* compute wrapper length */ Chris@43: s = strm->state; Chris@43: switch (s->wrap) { Chris@43: case 0: /* raw deflate */ Chris@43: wraplen = 0; Chris@43: break; Chris@43: case 1: /* zlib wrapper */ Chris@43: wraplen = 6 + (s->strstart ? 4 : 0); Chris@43: break; Chris@43: case 2: /* gzip wrapper */ Chris@43: wraplen = 18; Chris@43: if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ Chris@43: if (s->gzhead->extra != Z_NULL) Chris@43: wraplen += 2 + s->gzhead->extra_len; Chris@43: str = s->gzhead->name; Chris@43: if (str != Z_NULL) Chris@43: do { Chris@43: wraplen++; Chris@43: } while (*str++); Chris@43: str = s->gzhead->comment; Chris@43: if (str != Z_NULL) Chris@43: do { Chris@43: wraplen++; Chris@43: } while (*str++); Chris@43: if (s->gzhead->hcrc) Chris@43: wraplen += 2; Chris@43: } Chris@43: break; Chris@43: default: /* for compiler happiness */ Chris@43: wraplen = 6; Chris@43: } Chris@43: Chris@43: /* if not default parameters, return conservative bound */ Chris@43: if (s->w_bits != 15 || s->hash_bits != 8 + 7) Chris@43: return complen + wraplen; Chris@43: Chris@43: /* default settings: return tight bound for that case */ Chris@43: return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + Chris@43: (sourceLen >> 25) + 13 - 6 + wraplen; Chris@43: } Chris@43: Chris@43: /* ========================================================================= Chris@43: * Put a short in the pending buffer. The 16-bit value is put in MSB order. Chris@43: * IN assertion: the stream state is correct and there is enough room in Chris@43: * pending_buf. Chris@43: */ Chris@43: local void putShortMSB (s, b) Chris@43: deflate_state *s; Chris@43: uInt b; Chris@43: { Chris@43: put_byte(s, (Byte)(b >> 8)); Chris@43: put_byte(s, (Byte)(b & 0xff)); Chris@43: } Chris@43: Chris@43: /* ========================================================================= Chris@43: * Flush as much pending output as possible. All deflate() output goes Chris@43: * through this function so some applications may wish to modify it Chris@43: * to avoid allocating a large strm->next_out buffer and copying into it. Chris@43: * (See also read_buf()). Chris@43: */ Chris@43: local void flush_pending(strm) Chris@43: z_streamp strm; Chris@43: { Chris@43: unsigned len; Chris@43: deflate_state *s = strm->state; Chris@43: Chris@43: _tr_flush_bits(s); Chris@43: len = s->pending; Chris@43: if (len > strm->avail_out) len = strm->avail_out; Chris@43: if (len == 0) return; Chris@43: Chris@43: zmemcpy(strm->next_out, s->pending_out, len); Chris@43: strm->next_out += len; Chris@43: s->pending_out += len; Chris@43: strm->total_out += len; Chris@43: strm->avail_out -= len; Chris@43: s->pending -= len; Chris@43: if (s->pending == 0) { Chris@43: s->pending_out = s->pending_buf; Chris@43: } Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflate (strm, flush) Chris@43: z_streamp strm; Chris@43: int flush; Chris@43: { Chris@43: int old_flush; /* value of flush param for previous deflate call */ Chris@43: deflate_state *s; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL || Chris@43: flush > Z_BLOCK || flush < 0) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: s = strm->state; Chris@43: Chris@43: if (strm->next_out == Z_NULL || Chris@43: (strm->next_in == Z_NULL && strm->avail_in != 0) || Chris@43: (s->status == FINISH_STATE && flush != Z_FINISH)) { Chris@43: ERR_RETURN(strm, Z_STREAM_ERROR); Chris@43: } Chris@43: if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); Chris@43: Chris@43: s->strm = strm; /* just in case */ Chris@43: old_flush = s->last_flush; Chris@43: s->last_flush = flush; Chris@43: Chris@43: /* Write the header */ Chris@43: if (s->status == INIT_STATE) { Chris@43: #ifdef GZIP Chris@43: if (s->wrap == 2) { Chris@43: strm->adler = crc32(0L, Z_NULL, 0); Chris@43: put_byte(s, 31); Chris@43: put_byte(s, 139); Chris@43: put_byte(s, 8); Chris@43: if (s->gzhead == Z_NULL) { Chris@43: put_byte(s, 0); Chris@43: put_byte(s, 0); Chris@43: put_byte(s, 0); Chris@43: put_byte(s, 0); Chris@43: put_byte(s, 0); Chris@43: put_byte(s, s->level == 9 ? 2 : Chris@43: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? Chris@43: 4 : 0)); Chris@43: put_byte(s, OS_CODE); Chris@43: s->status = BUSY_STATE; Chris@43: } Chris@43: else { Chris@43: put_byte(s, (s->gzhead->text ? 1 : 0) + Chris@43: (s->gzhead->hcrc ? 2 : 0) + Chris@43: (s->gzhead->extra == Z_NULL ? 0 : 4) + Chris@43: (s->gzhead->name == Z_NULL ? 0 : 8) + Chris@43: (s->gzhead->comment == Z_NULL ? 0 : 16) Chris@43: ); Chris@43: put_byte(s, (Byte)(s->gzhead->time & 0xff)); Chris@43: put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); Chris@43: put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); Chris@43: put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); Chris@43: put_byte(s, s->level == 9 ? 2 : Chris@43: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? Chris@43: 4 : 0)); Chris@43: put_byte(s, s->gzhead->os & 0xff); Chris@43: if (s->gzhead->extra != Z_NULL) { Chris@43: put_byte(s, s->gzhead->extra_len & 0xff); Chris@43: put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); Chris@43: } Chris@43: if (s->gzhead->hcrc) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf, Chris@43: s->pending); Chris@43: s->gzindex = 0; Chris@43: s->status = EXTRA_STATE; Chris@43: } Chris@43: } Chris@43: else Chris@43: #endif Chris@43: { Chris@43: uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; Chris@43: uInt level_flags; Chris@43: Chris@43: if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) Chris@43: level_flags = 0; Chris@43: else if (s->level < 6) Chris@43: level_flags = 1; Chris@43: else if (s->level == 6) Chris@43: level_flags = 2; Chris@43: else Chris@43: level_flags = 3; Chris@43: header |= (level_flags << 6); Chris@43: if (s->strstart != 0) header |= PRESET_DICT; Chris@43: header += 31 - (header % 31); Chris@43: Chris@43: s->status = BUSY_STATE; Chris@43: putShortMSB(s, header); Chris@43: Chris@43: /* Save the adler32 of the preset dictionary: */ Chris@43: if (s->strstart != 0) { Chris@43: putShortMSB(s, (uInt)(strm->adler >> 16)); Chris@43: putShortMSB(s, (uInt)(strm->adler & 0xffff)); Chris@43: } Chris@43: strm->adler = adler32(0L, Z_NULL, 0); Chris@43: } Chris@43: } Chris@43: #ifdef GZIP Chris@43: if (s->status == EXTRA_STATE) { Chris@43: if (s->gzhead->extra != Z_NULL) { Chris@43: uInt beg = s->pending; /* start of bytes to update crc */ Chris@43: Chris@43: while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { Chris@43: if (s->pending == s->pending_buf_size) { Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: flush_pending(strm); Chris@43: beg = s->pending; Chris@43: if (s->pending == s->pending_buf_size) Chris@43: break; Chris@43: } Chris@43: put_byte(s, s->gzhead->extra[s->gzindex]); Chris@43: s->gzindex++; Chris@43: } Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: if (s->gzindex == s->gzhead->extra_len) { Chris@43: s->gzindex = 0; Chris@43: s->status = NAME_STATE; Chris@43: } Chris@43: } Chris@43: else Chris@43: s->status = NAME_STATE; Chris@43: } Chris@43: if (s->status == NAME_STATE) { Chris@43: if (s->gzhead->name != Z_NULL) { Chris@43: uInt beg = s->pending; /* start of bytes to update crc */ Chris@43: int val; Chris@43: Chris@43: do { Chris@43: if (s->pending == s->pending_buf_size) { Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: flush_pending(strm); Chris@43: beg = s->pending; Chris@43: if (s->pending == s->pending_buf_size) { Chris@43: val = 1; Chris@43: break; Chris@43: } Chris@43: } Chris@43: val = s->gzhead->name[s->gzindex++]; Chris@43: put_byte(s, val); Chris@43: } while (val != 0); Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: if (val == 0) { Chris@43: s->gzindex = 0; Chris@43: s->status = COMMENT_STATE; Chris@43: } Chris@43: } Chris@43: else Chris@43: s->status = COMMENT_STATE; Chris@43: } Chris@43: if (s->status == COMMENT_STATE) { Chris@43: if (s->gzhead->comment != Z_NULL) { Chris@43: uInt beg = s->pending; /* start of bytes to update crc */ Chris@43: int val; Chris@43: Chris@43: do { Chris@43: if (s->pending == s->pending_buf_size) { Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: flush_pending(strm); Chris@43: beg = s->pending; Chris@43: if (s->pending == s->pending_buf_size) { Chris@43: val = 1; Chris@43: break; Chris@43: } Chris@43: } Chris@43: val = s->gzhead->comment[s->gzindex++]; Chris@43: put_byte(s, val); Chris@43: } while (val != 0); Chris@43: if (s->gzhead->hcrc && s->pending > beg) Chris@43: strm->adler = crc32(strm->adler, s->pending_buf + beg, Chris@43: s->pending - beg); Chris@43: if (val == 0) Chris@43: s->status = HCRC_STATE; Chris@43: } Chris@43: else Chris@43: s->status = HCRC_STATE; Chris@43: } Chris@43: if (s->status == HCRC_STATE) { Chris@43: if (s->gzhead->hcrc) { Chris@43: if (s->pending + 2 > s->pending_buf_size) Chris@43: flush_pending(strm); Chris@43: if (s->pending + 2 <= s->pending_buf_size) { Chris@43: put_byte(s, (Byte)(strm->adler & 0xff)); Chris@43: put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); Chris@43: strm->adler = crc32(0L, Z_NULL, 0); Chris@43: s->status = BUSY_STATE; Chris@43: } Chris@43: } Chris@43: else Chris@43: s->status = BUSY_STATE; Chris@43: } Chris@43: #endif Chris@43: Chris@43: /* Flush as much pending output as possible */ Chris@43: if (s->pending != 0) { Chris@43: flush_pending(strm); Chris@43: if (strm->avail_out == 0) { Chris@43: /* Since avail_out is 0, deflate will be called again with Chris@43: * more output space, but possibly with both pending and Chris@43: * avail_in equal to zero. There won't be anything to do, Chris@43: * but this is not an error situation so make sure we Chris@43: * return OK instead of BUF_ERROR at next call of deflate: Chris@43: */ Chris@43: s->last_flush = -1; Chris@43: return Z_OK; Chris@43: } Chris@43: Chris@43: /* Make sure there is something to do and avoid duplicate consecutive Chris@43: * flushes. For repeated and useless calls with Z_FINISH, we keep Chris@43: * returning Z_STREAM_END instead of Z_BUF_ERROR. Chris@43: */ Chris@43: } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && Chris@43: flush != Z_FINISH) { Chris@43: ERR_RETURN(strm, Z_BUF_ERROR); Chris@43: } Chris@43: Chris@43: /* User must not provide more input after the first FINISH: */ Chris@43: if (s->status == FINISH_STATE && strm->avail_in != 0) { Chris@43: ERR_RETURN(strm, Z_BUF_ERROR); Chris@43: } Chris@43: Chris@43: /* Start a new block or continue the current one. Chris@43: */ Chris@43: if (strm->avail_in != 0 || s->lookahead != 0 || Chris@43: (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { Chris@43: block_state bstate; Chris@43: Chris@43: bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : Chris@43: (s->strategy == Z_RLE ? deflate_rle(s, flush) : Chris@43: (*(configuration_table[s->level].func))(s, flush)); Chris@43: Chris@43: if (bstate == finish_started || bstate == finish_done) { Chris@43: s->status = FINISH_STATE; Chris@43: } Chris@43: if (bstate == need_more || bstate == finish_started) { Chris@43: if (strm->avail_out == 0) { Chris@43: s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ Chris@43: } Chris@43: return Z_OK; Chris@43: /* If flush != Z_NO_FLUSH && avail_out == 0, the next call Chris@43: * of deflate should use the same flush parameter to make sure Chris@43: * that the flush is complete. So we don't have to output an Chris@43: * empty block here, this will be done at next call. This also Chris@43: * ensures that for a very small output buffer, we emit at most Chris@43: * one empty block. Chris@43: */ Chris@43: } Chris@43: if (bstate == block_done) { Chris@43: if (flush == Z_PARTIAL_FLUSH) { Chris@43: _tr_align(s); Chris@43: } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ Chris@43: _tr_stored_block(s, (char*)0, 0L, 0); Chris@43: /* For a full flush, this empty block will be recognized Chris@43: * as a special marker by inflate_sync(). Chris@43: */ Chris@43: if (flush == Z_FULL_FLUSH) { Chris@43: CLEAR_HASH(s); /* forget history */ Chris@43: if (s->lookahead == 0) { Chris@43: s->strstart = 0; Chris@43: s->block_start = 0L; Chris@43: s->insert = 0; Chris@43: } Chris@43: } Chris@43: } Chris@43: flush_pending(strm); Chris@43: if (strm->avail_out == 0) { Chris@43: s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ Chris@43: return Z_OK; Chris@43: } Chris@43: } Chris@43: } Chris@43: Assert(strm->avail_out > 0, "bug2"); Chris@43: Chris@43: if (flush != Z_FINISH) return Z_OK; Chris@43: if (s->wrap <= 0) return Z_STREAM_END; Chris@43: Chris@43: /* Write the trailer */ Chris@43: #ifdef GZIP Chris@43: if (s->wrap == 2) { Chris@43: put_byte(s, (Byte)(strm->adler & 0xff)); Chris@43: put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); Chris@43: put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); Chris@43: put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); Chris@43: put_byte(s, (Byte)(strm->total_in & 0xff)); Chris@43: put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); Chris@43: put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); Chris@43: put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); Chris@43: } Chris@43: else Chris@43: #endif Chris@43: { Chris@43: putShortMSB(s, (uInt)(strm->adler >> 16)); Chris@43: putShortMSB(s, (uInt)(strm->adler & 0xffff)); Chris@43: } Chris@43: flush_pending(strm); Chris@43: /* If avail_out is zero, the application will call deflate again Chris@43: * to flush the rest. Chris@43: */ Chris@43: if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ Chris@43: return s->pending != 0 ? Z_OK : Z_STREAM_END; Chris@43: } Chris@43: Chris@43: /* ========================================================================= */ Chris@43: int ZEXPORT deflateEnd (strm) Chris@43: z_streamp strm; Chris@43: { Chris@43: int status; Chris@43: Chris@43: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; Chris@43: Chris@43: status = strm->state->status; Chris@43: if (status != INIT_STATE && Chris@43: status != EXTRA_STATE && Chris@43: status != NAME_STATE && Chris@43: status != COMMENT_STATE && Chris@43: status != HCRC_STATE && Chris@43: status != BUSY_STATE && Chris@43: status != FINISH_STATE) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: Chris@43: /* Deallocate in reverse order of allocations: */ Chris@43: TRY_FREE(strm, strm->state->pending_buf); Chris@43: TRY_FREE(strm, strm->state->head); Chris@43: TRY_FREE(strm, strm->state->prev); Chris@43: TRY_FREE(strm, strm->state->window); Chris@43: Chris@43: ZFREE(strm, strm->state); Chris@43: strm->state = Z_NULL; Chris@43: Chris@43: return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; Chris@43: } Chris@43: Chris@43: /* ========================================================================= Chris@43: * Copy the source state to the destination state. Chris@43: * To simplify the source, this is not supported for 16-bit MSDOS (which Chris@43: * doesn't have enough memory anyway to duplicate compression states). Chris@43: */ Chris@43: int ZEXPORT deflateCopy (dest, source) Chris@43: z_streamp dest; Chris@43: z_streamp source; Chris@43: { Chris@43: #ifdef MAXSEG_64K Chris@43: return Z_STREAM_ERROR; Chris@43: #else Chris@43: deflate_state *ds; Chris@43: deflate_state *ss; Chris@43: ushf *overlay; Chris@43: Chris@43: Chris@43: if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { Chris@43: return Z_STREAM_ERROR; Chris@43: } Chris@43: Chris@43: ss = source->state; Chris@43: Chris@43: zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); Chris@43: Chris@43: ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); Chris@43: if (ds == Z_NULL) return Z_MEM_ERROR; Chris@43: dest->state = (struct internal_state FAR *) ds; Chris@43: zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state)); Chris@43: ds->strm = dest; Chris@43: Chris@43: ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); Chris@43: ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); Chris@43: ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); Chris@43: overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); Chris@43: ds->pending_buf = (uchf *) overlay; Chris@43: Chris@43: if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || Chris@43: ds->pending_buf == Z_NULL) { Chris@43: deflateEnd (dest); Chris@43: return Z_MEM_ERROR; Chris@43: } Chris@43: /* following zmemcpy do not work for 16-bit MSDOS */ Chris@43: zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); Chris@43: zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos)); Chris@43: zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos)); Chris@43: zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); Chris@43: Chris@43: ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); Chris@43: ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); Chris@43: ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; Chris@43: Chris@43: ds->l_desc.dyn_tree = ds->dyn_ltree; Chris@43: ds->d_desc.dyn_tree = ds->dyn_dtree; Chris@43: ds->bl_desc.dyn_tree = ds->bl_tree; Chris@43: Chris@43: return Z_OK; Chris@43: #endif /* MAXSEG_64K */ Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * Read a new buffer from the current input stream, update the adler32 Chris@43: * and total number of bytes read. All deflate() input goes through Chris@43: * this function so some applications may wish to modify it to avoid Chris@43: * allocating a large strm->next_in buffer and copying from it. Chris@43: * (See also flush_pending()). Chris@43: */ Chris@43: local int read_buf(strm, buf, size) Chris@43: z_streamp strm; Chris@43: Bytef *buf; Chris@43: unsigned size; Chris@43: { Chris@43: unsigned len = strm->avail_in; Chris@43: Chris@43: if (len > size) len = size; Chris@43: if (len == 0) return 0; Chris@43: Chris@43: strm->avail_in -= len; Chris@43: Chris@43: zmemcpy(buf, strm->next_in, len); Chris@43: if (strm->state->wrap == 1) { Chris@43: strm->adler = adler32(strm->adler, buf, len); Chris@43: } Chris@43: #ifdef GZIP Chris@43: else if (strm->state->wrap == 2) { Chris@43: strm->adler = crc32(strm->adler, buf, len); Chris@43: } Chris@43: #endif Chris@43: strm->next_in += len; Chris@43: strm->total_in += len; Chris@43: Chris@43: return (int)len; Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * Initialize the "longest match" routines for a new zlib stream Chris@43: */ Chris@43: local void lm_init (s) Chris@43: deflate_state *s; Chris@43: { Chris@43: s->window_size = (ulg)2L*s->w_size; Chris@43: Chris@43: CLEAR_HASH(s); Chris@43: Chris@43: /* Set the default configuration parameters: Chris@43: */ Chris@43: s->max_lazy_match = configuration_table[s->level].max_lazy; Chris@43: s->good_match = configuration_table[s->level].good_length; Chris@43: s->nice_match = configuration_table[s->level].nice_length; Chris@43: s->max_chain_length = configuration_table[s->level].max_chain; Chris@43: Chris@43: s->strstart = 0; Chris@43: s->block_start = 0L; Chris@43: s->lookahead = 0; Chris@43: s->insert = 0; Chris@43: s->match_length = s->prev_length = MIN_MATCH-1; Chris@43: s->match_available = 0; Chris@43: s->ins_h = 0; Chris@43: #ifndef FASTEST Chris@43: #ifdef ASMV Chris@43: match_init(); /* initialize the asm code */ Chris@43: #endif Chris@43: #endif Chris@43: } Chris@43: Chris@43: #ifndef FASTEST Chris@43: /* =========================================================================== Chris@43: * Set match_start to the longest match starting at the given string and Chris@43: * return its length. Matches shorter or equal to prev_length are discarded, Chris@43: * in which case the result is equal to prev_length and match_start is Chris@43: * garbage. Chris@43: * IN assertions: cur_match is the head of the hash chain for the current Chris@43: * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 Chris@43: * OUT assertion: the match length is not greater than s->lookahead. Chris@43: */ Chris@43: #ifndef ASMV Chris@43: /* For 80x86 and 680x0, an optimized version will be provided in match.asm or Chris@43: * match.S. The code will be functionally equivalent. Chris@43: */ Chris@43: local uInt longest_match(s, cur_match) Chris@43: deflate_state *s; Chris@43: IPos cur_match; /* current match */ Chris@43: { Chris@43: unsigned chain_length = s->max_chain_length;/* max hash chain length */ Chris@43: register Bytef *scan = s->window + s->strstart; /* current string */ Chris@43: register Bytef *match; /* matched string */ Chris@43: register int len; /* length of current match */ Chris@43: int best_len = s->prev_length; /* best match length so far */ Chris@43: int nice_match = s->nice_match; /* stop if match long enough */ Chris@43: IPos limit = s->strstart > (IPos)MAX_DIST(s) ? Chris@43: s->strstart - (IPos)MAX_DIST(s) : NIL; Chris@43: /* Stop when cur_match becomes <= limit. To simplify the code, Chris@43: * we prevent matches with the string of window index 0. Chris@43: */ Chris@43: Posf *prev = s->prev; Chris@43: uInt wmask = s->w_mask; Chris@43: Chris@43: #ifdef UNALIGNED_OK Chris@43: /* Compare two bytes at a time. Note: this is not always beneficial. Chris@43: * Try with and without -DUNALIGNED_OK to check. Chris@43: */ Chris@43: register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; Chris@43: register ush scan_start = *(ushf*)scan; Chris@43: register ush scan_end = *(ushf*)(scan+best_len-1); Chris@43: #else Chris@43: register Bytef *strend = s->window + s->strstart + MAX_MATCH; Chris@43: register Byte scan_end1 = scan[best_len-1]; Chris@43: register Byte scan_end = scan[best_len]; Chris@43: #endif Chris@43: Chris@43: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. Chris@43: * It is easy to get rid of this optimization if necessary. Chris@43: */ Chris@43: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); Chris@43: Chris@43: /* Do not waste too much time if we already have a good match: */ Chris@43: if (s->prev_length >= s->good_match) { Chris@43: chain_length >>= 2; Chris@43: } Chris@43: /* Do not look for matches beyond the end of the input. This is necessary Chris@43: * to make deflate deterministic. Chris@43: */ Chris@43: if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; Chris@43: Chris@43: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); Chris@43: Chris@43: do { Chris@43: Assert(cur_match < s->strstart, "no future"); Chris@43: match = s->window + cur_match; Chris@43: Chris@43: /* Skip to next match if the match length cannot increase Chris@43: * or if the match length is less than 2. Note that the checks below Chris@43: * for insufficient lookahead only occur occasionally for performance Chris@43: * reasons. Therefore uninitialized memory will be accessed, and Chris@43: * conditional jumps will be made that depend on those values. Chris@43: * However the length of the match is limited to the lookahead, so Chris@43: * the output of deflate is not affected by the uninitialized values. Chris@43: */ Chris@43: #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) Chris@43: /* This code assumes sizeof(unsigned short) == 2. Do not use Chris@43: * UNALIGNED_OK if your compiler uses a different size. Chris@43: */ Chris@43: if (*(ushf*)(match+best_len-1) != scan_end || Chris@43: *(ushf*)match != scan_start) continue; Chris@43: Chris@43: /* It is not necessary to compare scan[2] and match[2] since they are Chris@43: * always equal when the other bytes match, given that the hash keys Chris@43: * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at Chris@43: * strstart+3, +5, ... up to strstart+257. We check for insufficient Chris@43: * lookahead only every 4th comparison; the 128th check will be made Chris@43: * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is Chris@43: * necessary to put more guard bytes at the end of the window, or Chris@43: * to check more often for insufficient lookahead. Chris@43: */ Chris@43: Assert(scan[2] == match[2], "scan[2]?"); Chris@43: scan++, match++; Chris@43: do { Chris@43: } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && Chris@43: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && Chris@43: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && Chris@43: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && Chris@43: scan < strend); Chris@43: /* The funny "do {}" generates better code on most compilers */ Chris@43: Chris@43: /* Here, scan <= window+strstart+257 */ Chris@43: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); Chris@43: if (*scan == *match) scan++; Chris@43: Chris@43: len = (MAX_MATCH - 1) - (int)(strend-scan); Chris@43: scan = strend - (MAX_MATCH-1); Chris@43: Chris@43: #else /* UNALIGNED_OK */ Chris@43: Chris@43: if (match[best_len] != scan_end || Chris@43: match[best_len-1] != scan_end1 || Chris@43: *match != *scan || Chris@43: *++match != scan[1]) continue; Chris@43: Chris@43: /* The check at best_len-1 can be removed because it will be made Chris@43: * again later. (This heuristic is not always a win.) Chris@43: * It is not necessary to compare scan[2] and match[2] since they Chris@43: * are always equal when the other bytes match, given that Chris@43: * the hash keys are equal and that HASH_BITS >= 8. Chris@43: */ Chris@43: scan += 2, match++; Chris@43: Assert(*scan == *match, "match[2]?"); Chris@43: Chris@43: /* We check for insufficient lookahead only every 8th comparison; Chris@43: * the 256th check will be made at strstart+258. Chris@43: */ Chris@43: do { Chris@43: } while (*++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: scan < strend); Chris@43: Chris@43: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); Chris@43: Chris@43: len = MAX_MATCH - (int)(strend - scan); Chris@43: scan = strend - MAX_MATCH; Chris@43: Chris@43: #endif /* UNALIGNED_OK */ Chris@43: Chris@43: if (len > best_len) { Chris@43: s->match_start = cur_match; Chris@43: best_len = len; Chris@43: if (len >= nice_match) break; Chris@43: #ifdef UNALIGNED_OK Chris@43: scan_end = *(ushf*)(scan+best_len-1); Chris@43: #else Chris@43: scan_end1 = scan[best_len-1]; Chris@43: scan_end = scan[best_len]; Chris@43: #endif Chris@43: } Chris@43: } while ((cur_match = prev[cur_match & wmask]) > limit Chris@43: && --chain_length != 0); Chris@43: Chris@43: if ((uInt)best_len <= s->lookahead) return (uInt)best_len; Chris@43: return s->lookahead; Chris@43: } Chris@43: #endif /* ASMV */ Chris@43: Chris@43: #else /* FASTEST */ Chris@43: Chris@43: /* --------------------------------------------------------------------------- Chris@43: * Optimized version for FASTEST only Chris@43: */ Chris@43: local uInt longest_match(s, cur_match) Chris@43: deflate_state *s; Chris@43: IPos cur_match; /* current match */ Chris@43: { Chris@43: register Bytef *scan = s->window + s->strstart; /* current string */ Chris@43: register Bytef *match; /* matched string */ Chris@43: register int len; /* length of current match */ Chris@43: register Bytef *strend = s->window + s->strstart + MAX_MATCH; Chris@43: Chris@43: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. Chris@43: * It is easy to get rid of this optimization if necessary. Chris@43: */ Chris@43: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); Chris@43: Chris@43: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); Chris@43: Chris@43: Assert(cur_match < s->strstart, "no future"); Chris@43: Chris@43: match = s->window + cur_match; Chris@43: Chris@43: /* Return failure if the match length is less than 2: Chris@43: */ Chris@43: if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; Chris@43: Chris@43: /* The check at best_len-1 can be removed because it will be made Chris@43: * again later. (This heuristic is not always a win.) Chris@43: * It is not necessary to compare scan[2] and match[2] since they Chris@43: * are always equal when the other bytes match, given that Chris@43: * the hash keys are equal and that HASH_BITS >= 8. Chris@43: */ Chris@43: scan += 2, match += 2; Chris@43: Assert(*scan == *match, "match[2]?"); Chris@43: Chris@43: /* We check for insufficient lookahead only every 8th comparison; Chris@43: * the 256th check will be made at strstart+258. Chris@43: */ Chris@43: do { Chris@43: } while (*++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: *++scan == *++match && *++scan == *++match && Chris@43: scan < strend); Chris@43: Chris@43: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); Chris@43: Chris@43: len = MAX_MATCH - (int)(strend - scan); Chris@43: Chris@43: if (len < MIN_MATCH) return MIN_MATCH - 1; Chris@43: Chris@43: s->match_start = cur_match; Chris@43: return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; Chris@43: } Chris@43: Chris@43: #endif /* FASTEST */ Chris@43: Chris@43: #ifdef DEBUG Chris@43: /* =========================================================================== Chris@43: * Check that the match at match_start is indeed a match. Chris@43: */ Chris@43: local void check_match(s, start, match, length) Chris@43: deflate_state *s; Chris@43: IPos start, match; Chris@43: int length; Chris@43: { Chris@43: /* check that the match is indeed a match */ Chris@43: if (zmemcmp(s->window + match, Chris@43: s->window + start, length) != EQUAL) { Chris@43: fprintf(stderr, " start %u, match %u, length %d\n", Chris@43: start, match, length); Chris@43: do { Chris@43: fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); Chris@43: } while (--length != 0); Chris@43: z_error("invalid match"); Chris@43: } Chris@43: if (z_verbose > 1) { Chris@43: fprintf(stderr,"\\[%d,%d]", start-match, length); Chris@43: do { putc(s->window[start++], stderr); } while (--length != 0); Chris@43: } Chris@43: } Chris@43: #else Chris@43: # define check_match(s, start, match, length) Chris@43: #endif /* DEBUG */ Chris@43: Chris@43: /* =========================================================================== Chris@43: * Fill the window when the lookahead becomes insufficient. Chris@43: * Updates strstart and lookahead. Chris@43: * Chris@43: * IN assertion: lookahead < MIN_LOOKAHEAD Chris@43: * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD Chris@43: * At least one byte has been read, or avail_in == 0; reads are Chris@43: * performed for at least two bytes (required for the zip translate_eol Chris@43: * option -- not supported here). Chris@43: */ Chris@43: local void fill_window(s) Chris@43: deflate_state *s; Chris@43: { Chris@43: register unsigned n, m; Chris@43: register Posf *p; Chris@43: unsigned more; /* Amount of free space at the end of the window. */ Chris@43: uInt wsize = s->w_size; Chris@43: Chris@43: Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); Chris@43: Chris@43: do { Chris@43: more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); Chris@43: Chris@43: /* Deal with !@#$% 64K limit: */ Chris@43: if (sizeof(int) <= 2) { Chris@43: if (more == 0 && s->strstart == 0 && s->lookahead == 0) { Chris@43: more = wsize; Chris@43: Chris@43: } else if (more == (unsigned)(-1)) { Chris@43: /* Very unlikely, but possible on 16 bit machine if Chris@43: * strstart == 0 && lookahead == 1 (input done a byte at time) Chris@43: */ Chris@43: more--; Chris@43: } Chris@43: } Chris@43: Chris@43: /* If the window is almost full and there is insufficient lookahead, Chris@43: * move the upper half to the lower one to make room in the upper half. Chris@43: */ Chris@43: if (s->strstart >= wsize+MAX_DIST(s)) { Chris@43: Chris@43: zmemcpy(s->window, s->window+wsize, (unsigned)wsize); Chris@43: s->match_start -= wsize; Chris@43: s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ Chris@43: s->block_start -= (long) wsize; Chris@43: Chris@43: /* Slide the hash table (could be avoided with 32 bit values Chris@43: at the expense of memory usage). We slide even when level == 0 Chris@43: to keep the hash table consistent if we switch back to level > 0 Chris@43: later. (Using level 0 permanently is not an optimal usage of Chris@43: zlib, so we don't care about this pathological case.) Chris@43: */ Chris@43: n = s->hash_size; Chris@43: p = &s->head[n]; Chris@43: do { Chris@43: m = *--p; Chris@43: *p = (Pos)(m >= wsize ? m-wsize : NIL); Chris@43: } while (--n); Chris@43: Chris@43: n = wsize; Chris@43: #ifndef FASTEST Chris@43: p = &s->prev[n]; Chris@43: do { Chris@43: m = *--p; Chris@43: *p = (Pos)(m >= wsize ? m-wsize : NIL); Chris@43: /* If n is not on any hash chain, prev[n] is garbage but Chris@43: * its value will never be used. Chris@43: */ Chris@43: } while (--n); Chris@43: #endif Chris@43: more += wsize; Chris@43: } Chris@43: if (s->strm->avail_in == 0) break; Chris@43: Chris@43: /* If there was no sliding: Chris@43: * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && Chris@43: * more == window_size - lookahead - strstart Chris@43: * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) Chris@43: * => more >= window_size - 2*WSIZE + 2 Chris@43: * In the BIG_MEM or MMAP case (not yet supported), Chris@43: * window_size == input_size + MIN_LOOKAHEAD && Chris@43: * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. Chris@43: * Otherwise, window_size == 2*WSIZE so more >= 2. Chris@43: * If there was sliding, more >= WSIZE. So in all cases, more >= 2. Chris@43: */ Chris@43: Assert(more >= 2, "more < 2"); Chris@43: Chris@43: n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); Chris@43: s->lookahead += n; Chris@43: Chris@43: /* Initialize the hash value now that we have some input: */ Chris@43: if (s->lookahead + s->insert >= MIN_MATCH) { Chris@43: uInt str = s->strstart - s->insert; Chris@43: s->ins_h = s->window[str]; Chris@43: UPDATE_HASH(s, s->ins_h, s->window[str + 1]); Chris@43: #if MIN_MATCH != 3 Chris@43: Call UPDATE_HASH() MIN_MATCH-3 more times Chris@43: #endif Chris@43: while (s->insert) { Chris@43: UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); Chris@43: #ifndef FASTEST Chris@43: s->prev[str & s->w_mask] = s->head[s->ins_h]; Chris@43: #endif Chris@43: s->head[s->ins_h] = (Pos)str; Chris@43: str++; Chris@43: s->insert--; Chris@43: if (s->lookahead + s->insert < MIN_MATCH) Chris@43: break; Chris@43: } Chris@43: } Chris@43: /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, Chris@43: * but this is not important since only literal bytes will be emitted. Chris@43: */ Chris@43: Chris@43: } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); Chris@43: Chris@43: /* If the WIN_INIT bytes after the end of the current data have never been Chris@43: * written, then zero those bytes in order to avoid memory check reports of Chris@43: * the use of uninitialized (or uninitialised as Julian writes) bytes by Chris@43: * the longest match routines. Update the high water mark for the next Chris@43: * time through here. WIN_INIT is set to MAX_MATCH since the longest match Chris@43: * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. Chris@43: */ Chris@43: if (s->high_water < s->window_size) { Chris@43: ulg curr = s->strstart + (ulg)(s->lookahead); Chris@43: ulg init; Chris@43: Chris@43: if (s->high_water < curr) { Chris@43: /* Previous high water mark below current data -- zero WIN_INIT Chris@43: * bytes or up to end of window, whichever is less. Chris@43: */ Chris@43: init = s->window_size - curr; Chris@43: if (init > WIN_INIT) Chris@43: init = WIN_INIT; Chris@43: zmemzero(s->window + curr, (unsigned)init); Chris@43: s->high_water = curr + init; Chris@43: } Chris@43: else if (s->high_water < (ulg)curr + WIN_INIT) { Chris@43: /* High water mark at or above current data, but below current data Chris@43: * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up Chris@43: * to end of window, whichever is less. Chris@43: */ Chris@43: init = (ulg)curr + WIN_INIT - s->high_water; Chris@43: if (init > s->window_size - s->high_water) Chris@43: init = s->window_size - s->high_water; Chris@43: zmemzero(s->window + s->high_water, (unsigned)init); Chris@43: s->high_water += init; Chris@43: } Chris@43: } Chris@43: Chris@43: Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, Chris@43: "not enough room for search"); Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * Flush the current block, with given end-of-file flag. Chris@43: * IN assertion: strstart is set to the end of the current match. Chris@43: */ Chris@43: #define FLUSH_BLOCK_ONLY(s, last) { \ Chris@43: _tr_flush_block(s, (s->block_start >= 0L ? \ Chris@43: (charf *)&s->window[(unsigned)s->block_start] : \ Chris@43: (charf *)Z_NULL), \ Chris@43: (ulg)((long)s->strstart - s->block_start), \ Chris@43: (last)); \ Chris@43: s->block_start = s->strstart; \ Chris@43: flush_pending(s->strm); \ Chris@43: Tracev((stderr,"[FLUSH]")); \ Chris@43: } Chris@43: Chris@43: /* Same but force premature exit if necessary. */ Chris@43: #define FLUSH_BLOCK(s, last) { \ Chris@43: FLUSH_BLOCK_ONLY(s, last); \ Chris@43: if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * Copy without compression as much as possible from the input stream, return Chris@43: * the current block state. Chris@43: * This function does not insert new strings in the dictionary since Chris@43: * uncompressible data is probably not useful. This function is used Chris@43: * only for the level=0 compression option. Chris@43: * NOTE: this function should be optimized to avoid extra copying from Chris@43: * window to pending_buf. Chris@43: */ Chris@43: local block_state deflate_stored(s, flush) Chris@43: deflate_state *s; Chris@43: int flush; Chris@43: { Chris@43: /* Stored blocks are limited to 0xffff bytes, pending_buf is limited Chris@43: * to pending_buf_size, and each stored block has a 5 byte header: Chris@43: */ Chris@43: ulg max_block_size = 0xffff; Chris@43: ulg max_start; Chris@43: Chris@43: if (max_block_size > s->pending_buf_size - 5) { Chris@43: max_block_size = s->pending_buf_size - 5; Chris@43: } Chris@43: Chris@43: /* Copy as much as possible from input to output: */ Chris@43: for (;;) { Chris@43: /* Fill the window as much as possible: */ Chris@43: if (s->lookahead <= 1) { Chris@43: Chris@43: Assert(s->strstart < s->w_size+MAX_DIST(s) || Chris@43: s->block_start >= (long)s->w_size, "slide too late"); Chris@43: Chris@43: fill_window(s); Chris@43: if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; Chris@43: Chris@43: if (s->lookahead == 0) break; /* flush the current block */ Chris@43: } Chris@43: Assert(s->block_start >= 0L, "block gone"); Chris@43: Chris@43: s->strstart += s->lookahead; Chris@43: s->lookahead = 0; Chris@43: Chris@43: /* Emit a stored block if pending_buf will be full: */ Chris@43: max_start = s->block_start + max_block_size; Chris@43: if (s->strstart == 0 || (ulg)s->strstart >= max_start) { Chris@43: /* strstart == 0 is possible when wraparound on 16-bit machine */ Chris@43: s->lookahead = (uInt)(s->strstart - max_start); Chris@43: s->strstart = (uInt)max_start; Chris@43: FLUSH_BLOCK(s, 0); Chris@43: } Chris@43: /* Flush if we may have to slide, otherwise block_start may become Chris@43: * negative and the data will be gone: Chris@43: */ Chris@43: if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { Chris@43: FLUSH_BLOCK(s, 0); Chris@43: } Chris@43: } Chris@43: s->insert = 0; Chris@43: if (flush == Z_FINISH) { Chris@43: FLUSH_BLOCK(s, 1); Chris@43: return finish_done; Chris@43: } Chris@43: if ((long)s->strstart > s->block_start) Chris@43: FLUSH_BLOCK(s, 0); Chris@43: return block_done; Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * Compress as much as possible from the input stream, return the current Chris@43: * block state. Chris@43: * This function does not perform lazy evaluation of matches and inserts Chris@43: * new strings in the dictionary only for unmatched strings or for short Chris@43: * matches. It is used only for the fast compression options. Chris@43: */ Chris@43: local block_state deflate_fast(s, flush) Chris@43: deflate_state *s; Chris@43: int flush; Chris@43: { Chris@43: IPos hash_head; /* head of the hash chain */ Chris@43: int bflush; /* set if current block must be flushed */ Chris@43: Chris@43: for (;;) { Chris@43: /* Make sure that we always have enough lookahead, except Chris@43: * at the end of the input file. We need MAX_MATCH bytes Chris@43: * for the next match, plus MIN_MATCH bytes to insert the Chris@43: * string following the next match. Chris@43: */ Chris@43: if (s->lookahead < MIN_LOOKAHEAD) { Chris@43: fill_window(s); Chris@43: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { Chris@43: return need_more; Chris@43: } Chris@43: if (s->lookahead == 0) break; /* flush the current block */ Chris@43: } Chris@43: Chris@43: /* Insert the string window[strstart .. strstart+2] in the Chris@43: * dictionary, and set hash_head to the head of the hash chain: Chris@43: */ Chris@43: hash_head = NIL; Chris@43: if (s->lookahead >= MIN_MATCH) { Chris@43: INSERT_STRING(s, s->strstart, hash_head); Chris@43: } Chris@43: Chris@43: /* Find the longest match, discarding those <= prev_length. Chris@43: * At this point we have always match_length < MIN_MATCH Chris@43: */ Chris@43: if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { Chris@43: /* To simplify the code, we prevent matches with the string Chris@43: * of window index 0 (in particular we have to avoid a match Chris@43: * of the string with itself at the start of the input file). Chris@43: */ Chris@43: s->match_length = longest_match (s, hash_head); Chris@43: /* longest_match() sets match_start */ Chris@43: } Chris@43: if (s->match_length >= MIN_MATCH) { Chris@43: check_match(s, s->strstart, s->match_start, s->match_length); Chris@43: Chris@43: _tr_tally_dist(s, s->strstart - s->match_start, Chris@43: s->match_length - MIN_MATCH, bflush); Chris@43: Chris@43: s->lookahead -= s->match_length; Chris@43: Chris@43: /* Insert new strings in the hash table only if the match length Chris@43: * is not too large. This saves time but degrades compression. Chris@43: */ Chris@43: #ifndef FASTEST Chris@43: if (s->match_length <= s->max_insert_length && Chris@43: s->lookahead >= MIN_MATCH) { Chris@43: s->match_length--; /* string at strstart already in table */ Chris@43: do { Chris@43: s->strstart++; Chris@43: INSERT_STRING(s, s->strstart, hash_head); Chris@43: /* strstart never exceeds WSIZE-MAX_MATCH, so there are Chris@43: * always MIN_MATCH bytes ahead. Chris@43: */ Chris@43: } while (--s->match_length != 0); Chris@43: s->strstart++; Chris@43: } else Chris@43: #endif Chris@43: { Chris@43: s->strstart += s->match_length; Chris@43: s->match_length = 0; Chris@43: s->ins_h = s->window[s->strstart]; Chris@43: UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); Chris@43: #if MIN_MATCH != 3 Chris@43: Call UPDATE_HASH() MIN_MATCH-3 more times Chris@43: #endif Chris@43: /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not Chris@43: * matter since it will be recomputed at next deflate call. Chris@43: */ Chris@43: } Chris@43: } else { Chris@43: /* No match, output a literal byte */ Chris@43: Tracevv((stderr,"%c", s->window[s->strstart])); Chris@43: _tr_tally_lit (s, s->window[s->strstart], bflush); Chris@43: s->lookahead--; Chris@43: s->strstart++; Chris@43: } Chris@43: if (bflush) FLUSH_BLOCK(s, 0); Chris@43: } Chris@43: s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; Chris@43: if (flush == Z_FINISH) { Chris@43: FLUSH_BLOCK(s, 1); Chris@43: return finish_done; Chris@43: } Chris@43: if (s->last_lit) Chris@43: FLUSH_BLOCK(s, 0); Chris@43: return block_done; Chris@43: } Chris@43: Chris@43: #ifndef FASTEST Chris@43: /* =========================================================================== Chris@43: * Same as above, but achieves better compression. We use a lazy Chris@43: * evaluation for matches: a match is finally adopted only if there is Chris@43: * no better match at the next window position. Chris@43: */ Chris@43: local block_state deflate_slow(s, flush) Chris@43: deflate_state *s; Chris@43: int flush; Chris@43: { Chris@43: IPos hash_head; /* head of hash chain */ Chris@43: int bflush; /* set if current block must be flushed */ Chris@43: Chris@43: /* Process the input block. */ Chris@43: for (;;) { Chris@43: /* Make sure that we always have enough lookahead, except Chris@43: * at the end of the input file. We need MAX_MATCH bytes Chris@43: * for the next match, plus MIN_MATCH bytes to insert the Chris@43: * string following the next match. Chris@43: */ Chris@43: if (s->lookahead < MIN_LOOKAHEAD) { Chris@43: fill_window(s); Chris@43: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { Chris@43: return need_more; Chris@43: } Chris@43: if (s->lookahead == 0) break; /* flush the current block */ Chris@43: } Chris@43: Chris@43: /* Insert the string window[strstart .. strstart+2] in the Chris@43: * dictionary, and set hash_head to the head of the hash chain: Chris@43: */ Chris@43: hash_head = NIL; Chris@43: if (s->lookahead >= MIN_MATCH) { Chris@43: INSERT_STRING(s, s->strstart, hash_head); Chris@43: } Chris@43: Chris@43: /* Find the longest match, discarding those <= prev_length. Chris@43: */ Chris@43: s->prev_length = s->match_length, s->prev_match = s->match_start; Chris@43: s->match_length = MIN_MATCH-1; Chris@43: Chris@43: if (hash_head != NIL && s->prev_length < s->max_lazy_match && Chris@43: s->strstart - hash_head <= MAX_DIST(s)) { Chris@43: /* To simplify the code, we prevent matches with the string Chris@43: * of window index 0 (in particular we have to avoid a match Chris@43: * of the string with itself at the start of the input file). Chris@43: */ Chris@43: s->match_length = longest_match (s, hash_head); Chris@43: /* longest_match() sets match_start */ Chris@43: Chris@43: if (s->match_length <= 5 && (s->strategy == Z_FILTERED Chris@43: #if TOO_FAR <= 32767 Chris@43: || (s->match_length == MIN_MATCH && Chris@43: s->strstart - s->match_start > TOO_FAR) Chris@43: #endif Chris@43: )) { Chris@43: Chris@43: /* If prev_match is also MIN_MATCH, match_start is garbage Chris@43: * but we will ignore the current match anyway. Chris@43: */ Chris@43: s->match_length = MIN_MATCH-1; Chris@43: } Chris@43: } Chris@43: /* If there was a match at the previous step and the current Chris@43: * match is not better, output the previous match: Chris@43: */ Chris@43: if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { Chris@43: uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; Chris@43: /* Do not insert strings in hash table beyond this. */ Chris@43: Chris@43: check_match(s, s->strstart-1, s->prev_match, s->prev_length); Chris@43: Chris@43: _tr_tally_dist(s, s->strstart -1 - s->prev_match, Chris@43: s->prev_length - MIN_MATCH, bflush); Chris@43: Chris@43: /* Insert in hash table all strings up to the end of the match. Chris@43: * strstart-1 and strstart are already inserted. If there is not Chris@43: * enough lookahead, the last two strings are not inserted in Chris@43: * the hash table. Chris@43: */ Chris@43: s->lookahead -= s->prev_length-1; Chris@43: s->prev_length -= 2; Chris@43: do { Chris@43: if (++s->strstart <= max_insert) { Chris@43: INSERT_STRING(s, s->strstart, hash_head); Chris@43: } Chris@43: } while (--s->prev_length != 0); Chris@43: s->match_available = 0; Chris@43: s->match_length = MIN_MATCH-1; Chris@43: s->strstart++; Chris@43: Chris@43: if (bflush) FLUSH_BLOCK(s, 0); Chris@43: Chris@43: } else if (s->match_available) { Chris@43: /* If there was no match at the previous position, output a Chris@43: * single literal. If there was a match but the current match Chris@43: * is longer, truncate the previous match to a single literal. Chris@43: */ Chris@43: Tracevv((stderr,"%c", s->window[s->strstart-1])); Chris@43: _tr_tally_lit(s, s->window[s->strstart-1], bflush); Chris@43: if (bflush) { Chris@43: FLUSH_BLOCK_ONLY(s, 0); Chris@43: } Chris@43: s->strstart++; Chris@43: s->lookahead--; Chris@43: if (s->strm->avail_out == 0) return need_more; Chris@43: } else { Chris@43: /* There is no previous match to compare with, wait for Chris@43: * the next step to decide. Chris@43: */ Chris@43: s->match_available = 1; Chris@43: s->strstart++; Chris@43: s->lookahead--; Chris@43: } Chris@43: } Chris@43: Assert (flush != Z_NO_FLUSH, "no flush?"); Chris@43: if (s->match_available) { Chris@43: Tracevv((stderr,"%c", s->window[s->strstart-1])); Chris@43: _tr_tally_lit(s, s->window[s->strstart-1], bflush); Chris@43: s->match_available = 0; Chris@43: } Chris@43: s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; Chris@43: if (flush == Z_FINISH) { Chris@43: FLUSH_BLOCK(s, 1); Chris@43: return finish_done; Chris@43: } Chris@43: if (s->last_lit) Chris@43: FLUSH_BLOCK(s, 0); Chris@43: return block_done; Chris@43: } Chris@43: #endif /* FASTEST */ Chris@43: Chris@43: /* =========================================================================== Chris@43: * For Z_RLE, simply look for runs of bytes, generate matches only of distance Chris@43: * one. Do not maintain a hash table. (It will be regenerated if this run of Chris@43: * deflate switches away from Z_RLE.) Chris@43: */ Chris@43: local block_state deflate_rle(s, flush) Chris@43: deflate_state *s; Chris@43: int flush; Chris@43: { Chris@43: int bflush; /* set if current block must be flushed */ Chris@43: uInt prev; /* byte at distance one to match */ Chris@43: Bytef *scan, *strend; /* scan goes up to strend for length of run */ Chris@43: Chris@43: for (;;) { Chris@43: /* Make sure that we always have enough lookahead, except Chris@43: * at the end of the input file. We need MAX_MATCH bytes Chris@43: * for the longest run, plus one for the unrolled loop. Chris@43: */ Chris@43: if (s->lookahead <= MAX_MATCH) { Chris@43: fill_window(s); Chris@43: if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { Chris@43: return need_more; Chris@43: } Chris@43: if (s->lookahead == 0) break; /* flush the current block */ Chris@43: } Chris@43: Chris@43: /* See how many times the previous byte repeats */ Chris@43: s->match_length = 0; Chris@43: if (s->lookahead >= MIN_MATCH && s->strstart > 0) { Chris@43: scan = s->window + s->strstart - 1; Chris@43: prev = *scan; Chris@43: if (prev == *++scan && prev == *++scan && prev == *++scan) { Chris@43: strend = s->window + s->strstart + MAX_MATCH; Chris@43: do { Chris@43: } while (prev == *++scan && prev == *++scan && Chris@43: prev == *++scan && prev == *++scan && Chris@43: prev == *++scan && prev == *++scan && Chris@43: prev == *++scan && prev == *++scan && Chris@43: scan < strend); Chris@43: s->match_length = MAX_MATCH - (int)(strend - scan); Chris@43: if (s->match_length > s->lookahead) Chris@43: s->match_length = s->lookahead; Chris@43: } Chris@43: Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan"); Chris@43: } Chris@43: Chris@43: /* Emit match if have run of MIN_MATCH or longer, else emit literal */ Chris@43: if (s->match_length >= MIN_MATCH) { Chris@43: check_match(s, s->strstart, s->strstart - 1, s->match_length); Chris@43: Chris@43: _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); Chris@43: Chris@43: s->lookahead -= s->match_length; Chris@43: s->strstart += s->match_length; Chris@43: s->match_length = 0; Chris@43: } else { Chris@43: /* No match, output a literal byte */ Chris@43: Tracevv((stderr,"%c", s->window[s->strstart])); Chris@43: _tr_tally_lit (s, s->window[s->strstart], bflush); Chris@43: s->lookahead--; Chris@43: s->strstart++; Chris@43: } Chris@43: if (bflush) FLUSH_BLOCK(s, 0); Chris@43: } Chris@43: s->insert = 0; Chris@43: if (flush == Z_FINISH) { Chris@43: FLUSH_BLOCK(s, 1); Chris@43: return finish_done; Chris@43: } Chris@43: if (s->last_lit) Chris@43: FLUSH_BLOCK(s, 0); Chris@43: return block_done; Chris@43: } Chris@43: Chris@43: /* =========================================================================== Chris@43: * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. Chris@43: * (It will be regenerated if this run of deflate switches away from Huffman.) Chris@43: */ Chris@43: local block_state deflate_huff(s, flush) Chris@43: deflate_state *s; Chris@43: int flush; Chris@43: { Chris@43: int bflush; /* set if current block must be flushed */ Chris@43: Chris@43: for (;;) { Chris@43: /* Make sure that we have a literal to write. */ Chris@43: if (s->lookahead == 0) { Chris@43: fill_window(s); Chris@43: if (s->lookahead == 0) { Chris@43: if (flush == Z_NO_FLUSH) Chris@43: return need_more; Chris@43: break; /* flush the current block */ Chris@43: } Chris@43: } Chris@43: Chris@43: /* Output a literal byte */ Chris@43: s->match_length = 0; Chris@43: Tracevv((stderr,"%c", s->window[s->strstart])); Chris@43: _tr_tally_lit (s, s->window[s->strstart], bflush); Chris@43: s->lookahead--; Chris@43: s->strstart++; Chris@43: if (bflush) FLUSH_BLOCK(s, 0); Chris@43: } Chris@43: s->insert = 0; Chris@43: if (flush == Z_FINISH) { Chris@43: FLUSH_BLOCK(s, 1); Chris@43: return finish_done; Chris@43: } Chris@43: if (s->last_lit) Chris@43: FLUSH_BLOCK(s, 0); Chris@43: return block_done; Chris@43: }