alpar@9: /* deflate.c -- compress data using the deflation algorithm alpar@9: * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler alpar@9: * For conditions of distribution and use, see copyright notice in zlib.h alpar@9: */ alpar@9: alpar@9: /* alpar@9: * ALGORITHM alpar@9: * alpar@9: * The "deflation" process depends on being able to identify portions alpar@9: * of the input text which are identical to earlier input (within a alpar@9: * sliding window trailing behind the input currently being processed). alpar@9: * alpar@9: * The most straightforward technique turns out to be the fastest for alpar@9: * most input files: try all possible matches and select the longest. alpar@9: * The key feature of this algorithm is that insertions into the string alpar@9: * dictionary are very simple and thus fast, and deletions are avoided alpar@9: * completely. Insertions are performed at each input character, whereas alpar@9: * string matches are performed only when the previous match ends. So it alpar@9: * is preferable to spend more time in matches to allow very fast string alpar@9: * insertions and avoid deletions. The matching algorithm for small alpar@9: * strings is inspired from that of Rabin & Karp. A brute force approach alpar@9: * is used to find longer strings when a small match has been found. alpar@9: * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze alpar@9: * (by Leonid Broukhis). alpar@9: * A previous version of this file used a more sophisticated algorithm alpar@9: * (by Fiala and Greene) which is guaranteed to run in linear amortized alpar@9: * time, but has a larger average cost, uses more memory and is patented. alpar@9: * However the F&G algorithm may be faster for some highly redundant alpar@9: * files if the parameter max_chain_length (described below) is too large. alpar@9: * alpar@9: * ACKNOWLEDGEMENTS alpar@9: * alpar@9: * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and alpar@9: * I found it in 'freeze' written by Leonid Broukhis. alpar@9: * Thanks to many people for bug reports and testing. alpar@9: * alpar@9: * REFERENCES alpar@9: * alpar@9: * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". alpar@9: * Available in http://www.ietf.org/rfc/rfc1951.txt alpar@9: * alpar@9: * A description of the Rabin and Karp algorithm is given in the book alpar@9: * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. alpar@9: * alpar@9: * Fiala,E.R., and Greene,D.H. alpar@9: * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 alpar@9: * alpar@9: */ alpar@9: alpar@9: /* @(#) $Id$ */ alpar@9: alpar@9: #include "deflate.h" alpar@9: alpar@9: const char deflate_copyright[] = alpar@9: " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler "; alpar@9: /* alpar@9: If you use the zlib library in a product, an acknowledgment is welcome alpar@9: in the documentation of your product. If for some reason you cannot alpar@9: include such an acknowledgment, I would appreciate that you keep this alpar@9: copyright string in the executable of your product. alpar@9: */ alpar@9: alpar@9: /* =========================================================================== alpar@9: * Function prototypes. alpar@9: */ alpar@9: typedef enum { alpar@9: need_more, /* block not completed, need more input or more output */ alpar@9: block_done, /* block flush performed */ alpar@9: finish_started, /* finish started, need only more output at next deflate */ alpar@9: finish_done /* finish done, accept no more input or output */ alpar@9: } block_state; alpar@9: alpar@9: typedef block_state (*compress_func) OF((deflate_state *s, int flush)); alpar@9: /* Compression function. Returns the block state after the call. */ alpar@9: alpar@9: local void fill_window OF((deflate_state *s)); alpar@9: local block_state deflate_stored OF((deflate_state *s, int flush)); alpar@9: local block_state deflate_fast OF((deflate_state *s, int flush)); alpar@9: #ifndef FASTEST alpar@9: local block_state deflate_slow OF((deflate_state *s, int flush)); alpar@9: #endif alpar@9: local block_state deflate_rle OF((deflate_state *s, int flush)); alpar@9: local block_state deflate_huff OF((deflate_state *s, int flush)); alpar@9: local void lm_init OF((deflate_state *s)); alpar@9: local void putShortMSB OF((deflate_state *s, uInt b)); alpar@9: local void flush_pending OF((z_streamp strm)); alpar@9: local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); alpar@9: #ifdef ASMV alpar@9: void match_init OF((void)); /* asm code initialization */ alpar@9: uInt longest_match OF((deflate_state *s, IPos cur_match)); alpar@9: #else alpar@9: local uInt longest_match OF((deflate_state *s, IPos cur_match)); alpar@9: #endif alpar@9: alpar@9: #ifdef DEBUG alpar@9: local void check_match OF((deflate_state *s, IPos start, IPos match, alpar@9: int length)); alpar@9: #endif alpar@9: alpar@9: /* =========================================================================== alpar@9: * Local data alpar@9: */ alpar@9: alpar@9: #define NIL 0 alpar@9: /* Tail of hash chains */ alpar@9: alpar@9: #ifndef TOO_FAR alpar@9: # define TOO_FAR 4096 alpar@9: #endif alpar@9: /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ alpar@9: alpar@9: /* Values for max_lazy_match, good_match and max_chain_length, depending on alpar@9: * the desired pack level (0..9). The values given below have been tuned to alpar@9: * exclude worst case performance for pathological files. Better values may be alpar@9: * found for specific files. alpar@9: */ alpar@9: typedef struct config_s { alpar@9: ush good_length; /* reduce lazy search above this match length */ alpar@9: ush max_lazy; /* do not perform lazy search above this match length */ alpar@9: ush nice_length; /* quit search above this match length */ alpar@9: ush max_chain; alpar@9: compress_func func; alpar@9: } config; alpar@9: alpar@9: #ifdef FASTEST alpar@9: local const config configuration_table[2] = { alpar@9: /* good lazy nice chain */ alpar@9: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ alpar@9: /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ alpar@9: #else alpar@9: local const config configuration_table[10] = { alpar@9: /* good lazy nice chain */ alpar@9: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ alpar@9: /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ alpar@9: /* 2 */ {4, 5, 16, 8, deflate_fast}, alpar@9: /* 3 */ {4, 6, 32, 32, deflate_fast}, alpar@9: alpar@9: /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ alpar@9: /* 5 */ {8, 16, 32, 32, deflate_slow}, alpar@9: /* 6 */ {8, 16, 128, 128, deflate_slow}, alpar@9: /* 7 */ {8, 32, 128, 256, deflate_slow}, alpar@9: /* 8 */ {32, 128, 258, 1024, deflate_slow}, alpar@9: /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ alpar@9: #endif alpar@9: alpar@9: /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 alpar@9: * For deflate_fast() (levels <= 3) good is ignored and lazy has a different alpar@9: * meaning. alpar@9: */ alpar@9: alpar@9: #define EQUAL 0 alpar@9: /* result of memcmp for equal strings */ alpar@9: alpar@9: #ifndef NO_DUMMY_DECL alpar@9: struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ alpar@9: #endif alpar@9: alpar@9: /* =========================================================================== alpar@9: * Update a hash value with the given input byte alpar@9: * IN assertion: all calls to to UPDATE_HASH are made with consecutive alpar@9: * input characters, so that a running hash key can be computed from the alpar@9: * previous key instead of complete recalculation each time. alpar@9: */ alpar@9: #define UPDATE_HASH(s,h,c) (h = (((h)<hash_shift) ^ (c)) & s->hash_mask) alpar@9: alpar@9: alpar@9: /* =========================================================================== alpar@9: * Insert string str in the dictionary and set match_head to the previous head alpar@9: * of the hash chain (the most recent string with same hash key). Return alpar@9: * the previous length of the hash chain. alpar@9: * If this file is compiled with -DFASTEST, the compression level is forced alpar@9: * to 1, and no hash chains are maintained. alpar@9: * IN assertion: all calls to to INSERT_STRING are made with consecutive alpar@9: * input characters and the first MIN_MATCH bytes of str are valid alpar@9: * (except for the last MIN_MATCH-1 bytes of the input file). alpar@9: */ alpar@9: #ifdef FASTEST alpar@9: #define INSERT_STRING(s, str, match_head) \ alpar@9: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ alpar@9: match_head = s->head[s->ins_h], \ alpar@9: s->head[s->ins_h] = (Pos)(str)) alpar@9: #else alpar@9: #define INSERT_STRING(s, str, match_head) \ alpar@9: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ alpar@9: match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ alpar@9: s->head[s->ins_h] = (Pos)(str)) alpar@9: #endif alpar@9: alpar@9: /* =========================================================================== alpar@9: * Initialize the hash table (avoiding 64K overflow for 16 bit systems). alpar@9: * prev[] will be initialized on the fly. alpar@9: */ alpar@9: #define CLEAR_HASH(s) \ alpar@9: s->head[s->hash_size-1] = NIL; \ alpar@9: zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateInit_(strm, level, version, stream_size) alpar@9: z_streamp strm; alpar@9: int level; alpar@9: const char *version; alpar@9: int stream_size; alpar@9: { alpar@9: return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, alpar@9: Z_DEFAULT_STRATEGY, version, stream_size); alpar@9: /* To do: ignore strm->next_in if we use it as window */ alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, alpar@9: version, stream_size) alpar@9: z_streamp strm; alpar@9: int level; alpar@9: int method; alpar@9: int windowBits; alpar@9: int memLevel; alpar@9: int strategy; alpar@9: const char *version; alpar@9: int stream_size; alpar@9: { alpar@9: deflate_state *s; alpar@9: int wrap = 1; alpar@9: static const char my_version[] = ZLIB_VERSION; alpar@9: alpar@9: ushf *overlay; alpar@9: /* We overlay pending_buf and d_buf+l_buf. This works since the average alpar@9: * output size for (length,distance) codes is <= 24 bits. alpar@9: */ alpar@9: alpar@9: if (version == Z_NULL || version[0] != my_version[0] || alpar@9: stream_size != sizeof(z_stream)) { alpar@9: return Z_VERSION_ERROR; alpar@9: } alpar@9: if (strm == Z_NULL) return Z_STREAM_ERROR; alpar@9: alpar@9: strm->msg = Z_NULL; alpar@9: if (strm->zalloc == (alloc_func)0) { alpar@9: strm->zalloc = zcalloc; alpar@9: strm->opaque = (voidpf)0; alpar@9: } alpar@9: if (strm->zfree == (free_func)0) strm->zfree = zcfree; alpar@9: alpar@9: #ifdef FASTEST alpar@9: if (level != 0) level = 1; alpar@9: #else alpar@9: if (level == Z_DEFAULT_COMPRESSION) level = 6; alpar@9: #endif alpar@9: alpar@9: if (windowBits < 0) { /* suppress zlib wrapper */ alpar@9: wrap = 0; alpar@9: windowBits = -windowBits; alpar@9: } alpar@9: #ifdef GZIP alpar@9: else if (windowBits > 15) { alpar@9: wrap = 2; /* write gzip wrapper instead */ alpar@9: windowBits -= 16; alpar@9: } alpar@9: #endif alpar@9: if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || alpar@9: windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || alpar@9: strategy < 0 || strategy > Z_FIXED) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ alpar@9: s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); alpar@9: if (s == Z_NULL) return Z_MEM_ERROR; alpar@9: strm->state = (struct internal_state FAR *)s; alpar@9: s->strm = strm; alpar@9: alpar@9: s->wrap = wrap; alpar@9: s->gzhead = Z_NULL; alpar@9: s->w_bits = windowBits; alpar@9: s->w_size = 1 << s->w_bits; alpar@9: s->w_mask = s->w_size - 1; alpar@9: alpar@9: s->hash_bits = memLevel + 7; alpar@9: s->hash_size = 1 << s->hash_bits; alpar@9: s->hash_mask = s->hash_size - 1; alpar@9: s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); alpar@9: alpar@9: s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); alpar@9: s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); alpar@9: s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); alpar@9: alpar@9: s->high_water = 0; /* nothing written to s->window yet */ alpar@9: alpar@9: s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ alpar@9: alpar@9: overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); alpar@9: s->pending_buf = (uchf *) overlay; alpar@9: s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); alpar@9: alpar@9: if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || alpar@9: s->pending_buf == Z_NULL) { alpar@9: s->status = FINISH_STATE; alpar@9: strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); alpar@9: deflateEnd (strm); alpar@9: return Z_MEM_ERROR; alpar@9: } alpar@9: s->d_buf = overlay + s->lit_bufsize/sizeof(ush); alpar@9: s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; alpar@9: alpar@9: s->level = level; alpar@9: s->strategy = strategy; alpar@9: s->method = (Byte)method; alpar@9: alpar@9: return deflateReset(strm); alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) alpar@9: z_streamp strm; alpar@9: const Bytef *dictionary; alpar@9: uInt dictLength; alpar@9: { alpar@9: deflate_state *s; alpar@9: uInt length = dictLength; alpar@9: uInt n; alpar@9: IPos hash_head = 0; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || alpar@9: strm->state->wrap == 2 || alpar@9: (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) alpar@9: return Z_STREAM_ERROR; alpar@9: alpar@9: s = strm->state; alpar@9: if (s->wrap) alpar@9: strm->adler = adler32(strm->adler, dictionary, dictLength); alpar@9: alpar@9: if (length < MIN_MATCH) return Z_OK; alpar@9: if (length > s->w_size) { alpar@9: length = s->w_size; alpar@9: dictionary += dictLength - length; /* use the tail of the dictionary */ alpar@9: } alpar@9: zmemcpy(s->window, dictionary, length); alpar@9: s->strstart = length; alpar@9: s->block_start = (long)length; alpar@9: alpar@9: /* Insert all strings in the hash table (except for the last two bytes). alpar@9: * s->lookahead stays null, so s->ins_h will be recomputed at the next alpar@9: * call of fill_window. alpar@9: */ alpar@9: s->ins_h = s->window[0]; alpar@9: UPDATE_HASH(s, s->ins_h, s->window[1]); alpar@9: for (n = 0; n <= length - MIN_MATCH; n++) { alpar@9: INSERT_STRING(s, n, hash_head); alpar@9: } alpar@9: if (hash_head) hash_head = 0; /* to make compiler happy */ alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateReset (strm) alpar@9: z_streamp strm; alpar@9: { alpar@9: deflate_state *s; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL || alpar@9: strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: alpar@9: strm->total_in = strm->total_out = 0; alpar@9: strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ alpar@9: strm->data_type = Z_UNKNOWN; alpar@9: alpar@9: s = (deflate_state *)strm->state; alpar@9: s->pending = 0; alpar@9: s->pending_out = s->pending_buf; alpar@9: alpar@9: if (s->wrap < 0) { alpar@9: s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ alpar@9: } alpar@9: s->status = s->wrap ? INIT_STATE : BUSY_STATE; alpar@9: strm->adler = alpar@9: #ifdef GZIP alpar@9: s->wrap == 2 ? crc32(0L, Z_NULL, 0) : alpar@9: #endif alpar@9: adler32(0L, Z_NULL, 0); alpar@9: s->last_flush = Z_NO_FLUSH; alpar@9: alpar@9: _tr_init(s); alpar@9: lm_init(s); alpar@9: alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateSetHeader (strm, head) alpar@9: z_streamp strm; alpar@9: gz_headerp head; alpar@9: { alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; alpar@9: if (strm->state->wrap != 2) return Z_STREAM_ERROR; alpar@9: strm->state->gzhead = head; alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflatePrime (strm, bits, value) alpar@9: z_streamp strm; alpar@9: int bits; alpar@9: int value; alpar@9: { alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; alpar@9: strm->state->bi_valid = bits; alpar@9: strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateParams(strm, level, strategy) alpar@9: z_streamp strm; alpar@9: int level; alpar@9: int strategy; alpar@9: { alpar@9: deflate_state *s; alpar@9: compress_func func; alpar@9: int err = Z_OK; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; alpar@9: s = strm->state; alpar@9: alpar@9: #ifdef FASTEST alpar@9: if (level != 0) level = 1; alpar@9: #else alpar@9: if (level == Z_DEFAULT_COMPRESSION) level = 6; alpar@9: #endif alpar@9: if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: func = configuration_table[s->level].func; alpar@9: alpar@9: if ((strategy != s->strategy || func != configuration_table[level].func) && alpar@9: strm->total_in != 0) { alpar@9: /* Flush the last buffer: */ alpar@9: err = deflate(strm, Z_BLOCK); alpar@9: } alpar@9: if (s->level != level) { alpar@9: s->level = level; alpar@9: s->max_lazy_match = configuration_table[level].max_lazy; alpar@9: s->good_match = configuration_table[level].good_length; alpar@9: s->nice_match = configuration_table[level].nice_length; alpar@9: s->max_chain_length = configuration_table[level].max_chain; alpar@9: } alpar@9: s->strategy = strategy; alpar@9: return err; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) alpar@9: z_streamp strm; alpar@9: int good_length; alpar@9: int max_lazy; alpar@9: int nice_length; alpar@9: int max_chain; alpar@9: { alpar@9: deflate_state *s; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; alpar@9: s = strm->state; alpar@9: s->good_match = good_length; alpar@9: s->max_lazy_match = max_lazy; alpar@9: s->nice_match = nice_length; alpar@9: s->max_chain_length = max_chain; alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= alpar@9: * For the default windowBits of 15 and memLevel of 8, this function returns alpar@9: * a close to exact, as well as small, upper bound on the compressed size. alpar@9: * They are coded as constants here for a reason--if the #define's are alpar@9: * changed, then this function needs to be changed as well. The return alpar@9: * value for 15 and 8 only works for those exact settings. alpar@9: * alpar@9: * For any setting other than those defaults for windowBits and memLevel, alpar@9: * the value returned is a conservative worst case for the maximum expansion alpar@9: * resulting from using fixed blocks instead of stored blocks, which deflate alpar@9: * can emit on compressed data for some combinations of the parameters. alpar@9: * alpar@9: * This function could be more sophisticated to provide closer upper bounds for alpar@9: * every combination of windowBits and memLevel. But even the conservative alpar@9: * upper bound of about 14% expansion does not seem onerous for output buffer alpar@9: * allocation. alpar@9: */ alpar@9: uLong ZEXPORT deflateBound(strm, sourceLen) alpar@9: z_streamp strm; alpar@9: uLong sourceLen; alpar@9: { alpar@9: deflate_state *s; alpar@9: uLong complen, wraplen; alpar@9: Bytef *str; alpar@9: alpar@9: /* conservative upper bound for compressed data */ alpar@9: complen = sourceLen + alpar@9: ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; alpar@9: alpar@9: /* if can't get parameters, return conservative bound plus zlib wrapper */ alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) alpar@9: return complen + 6; alpar@9: alpar@9: /* compute wrapper length */ alpar@9: s = strm->state; alpar@9: switch (s->wrap) { alpar@9: case 0: /* raw deflate */ alpar@9: wraplen = 0; alpar@9: break; alpar@9: case 1: /* zlib wrapper */ alpar@9: wraplen = 6 + (s->strstart ? 4 : 0); alpar@9: break; alpar@9: case 2: /* gzip wrapper */ alpar@9: wraplen = 18; alpar@9: if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ alpar@9: if (s->gzhead->extra != Z_NULL) alpar@9: wraplen += 2 + s->gzhead->extra_len; alpar@9: str = s->gzhead->name; alpar@9: if (str != Z_NULL) alpar@9: do { alpar@9: wraplen++; alpar@9: } while (*str++); alpar@9: str = s->gzhead->comment; alpar@9: if (str != Z_NULL) alpar@9: do { alpar@9: wraplen++; alpar@9: } while (*str++); alpar@9: if (s->gzhead->hcrc) alpar@9: wraplen += 2; alpar@9: } alpar@9: break; alpar@9: default: /* for compiler happiness */ alpar@9: wraplen = 6; alpar@9: } alpar@9: alpar@9: /* if not default parameters, return conservative bound */ alpar@9: if (s->w_bits != 15 || s->hash_bits != 8 + 7) alpar@9: return complen + wraplen; alpar@9: alpar@9: /* default settings: return tight bound for that case */ alpar@9: return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + alpar@9: (sourceLen >> 25) + 13 - 6 + wraplen; alpar@9: } alpar@9: alpar@9: /* ========================================================================= alpar@9: * Put a short in the pending buffer. The 16-bit value is put in MSB order. alpar@9: * IN assertion: the stream state is correct and there is enough room in alpar@9: * pending_buf. alpar@9: */ alpar@9: local void putShortMSB (s, b) alpar@9: deflate_state *s; alpar@9: uInt b; alpar@9: { alpar@9: put_byte(s, (Byte)(b >> 8)); alpar@9: put_byte(s, (Byte)(b & 0xff)); alpar@9: } alpar@9: alpar@9: /* ========================================================================= alpar@9: * Flush as much pending output as possible. All deflate() output goes alpar@9: * through this function so some applications may wish to modify it alpar@9: * to avoid allocating a large strm->next_out buffer and copying into it. alpar@9: * (See also read_buf()). alpar@9: */ alpar@9: local void flush_pending(strm) alpar@9: z_streamp strm; alpar@9: { alpar@9: unsigned len = strm->state->pending; alpar@9: alpar@9: if (len > strm->avail_out) len = strm->avail_out; alpar@9: if (len == 0) return; alpar@9: alpar@9: zmemcpy(strm->next_out, strm->state->pending_out, len); alpar@9: strm->next_out += len; alpar@9: strm->state->pending_out += len; alpar@9: strm->total_out += len; alpar@9: strm->avail_out -= len; alpar@9: strm->state->pending -= len; alpar@9: if (strm->state->pending == 0) { alpar@9: strm->state->pending_out = strm->state->pending_buf; alpar@9: } alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflate (strm, flush) alpar@9: z_streamp strm; alpar@9: int flush; alpar@9: { alpar@9: int old_flush; /* value of flush param for previous deflate call */ alpar@9: deflate_state *s; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL || alpar@9: flush > Z_BLOCK || flush < 0) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: s = strm->state; alpar@9: alpar@9: if (strm->next_out == Z_NULL || alpar@9: (strm->next_in == Z_NULL && strm->avail_in != 0) || alpar@9: (s->status == FINISH_STATE && flush != Z_FINISH)) { alpar@9: ERR_RETURN(strm, Z_STREAM_ERROR); alpar@9: } alpar@9: if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); alpar@9: alpar@9: s->strm = strm; /* just in case */ alpar@9: old_flush = s->last_flush; alpar@9: s->last_flush = flush; alpar@9: alpar@9: /* Write the header */ alpar@9: if (s->status == INIT_STATE) { alpar@9: #ifdef GZIP alpar@9: if (s->wrap == 2) { alpar@9: strm->adler = crc32(0L, Z_NULL, 0); alpar@9: put_byte(s, 31); alpar@9: put_byte(s, 139); alpar@9: put_byte(s, 8); alpar@9: if (s->gzhead == Z_NULL) { alpar@9: put_byte(s, 0); alpar@9: put_byte(s, 0); alpar@9: put_byte(s, 0); alpar@9: put_byte(s, 0); alpar@9: put_byte(s, 0); alpar@9: put_byte(s, s->level == 9 ? 2 : alpar@9: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? alpar@9: 4 : 0)); alpar@9: put_byte(s, OS_CODE); alpar@9: s->status = BUSY_STATE; alpar@9: } alpar@9: else { alpar@9: put_byte(s, (s->gzhead->text ? 1 : 0) + alpar@9: (s->gzhead->hcrc ? 2 : 0) + alpar@9: (s->gzhead->extra == Z_NULL ? 0 : 4) + alpar@9: (s->gzhead->name == Z_NULL ? 0 : 8) + alpar@9: (s->gzhead->comment == Z_NULL ? 0 : 16) alpar@9: ); alpar@9: put_byte(s, (Byte)(s->gzhead->time & 0xff)); alpar@9: put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); alpar@9: put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); alpar@9: put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); alpar@9: put_byte(s, s->level == 9 ? 2 : alpar@9: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? alpar@9: 4 : 0)); alpar@9: put_byte(s, s->gzhead->os & 0xff); alpar@9: if (s->gzhead->extra != Z_NULL) { alpar@9: put_byte(s, s->gzhead->extra_len & 0xff); alpar@9: put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); alpar@9: } alpar@9: if (s->gzhead->hcrc) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf, alpar@9: s->pending); alpar@9: s->gzindex = 0; alpar@9: s->status = EXTRA_STATE; alpar@9: } alpar@9: } alpar@9: else alpar@9: #endif alpar@9: { alpar@9: uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; alpar@9: uInt level_flags; alpar@9: alpar@9: if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) alpar@9: level_flags = 0; alpar@9: else if (s->level < 6) alpar@9: level_flags = 1; alpar@9: else if (s->level == 6) alpar@9: level_flags = 2; alpar@9: else alpar@9: level_flags = 3; alpar@9: header |= (level_flags << 6); alpar@9: if (s->strstart != 0) header |= PRESET_DICT; alpar@9: header += 31 - (header % 31); alpar@9: alpar@9: s->status = BUSY_STATE; alpar@9: putShortMSB(s, header); alpar@9: alpar@9: /* Save the adler32 of the preset dictionary: */ alpar@9: if (s->strstart != 0) { alpar@9: putShortMSB(s, (uInt)(strm->adler >> 16)); alpar@9: putShortMSB(s, (uInt)(strm->adler & 0xffff)); alpar@9: } alpar@9: strm->adler = adler32(0L, Z_NULL, 0); alpar@9: } alpar@9: } alpar@9: #ifdef GZIP alpar@9: if (s->status == EXTRA_STATE) { alpar@9: if (s->gzhead->extra != Z_NULL) { alpar@9: uInt beg = s->pending; /* start of bytes to update crc */ alpar@9: alpar@9: while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { alpar@9: if (s->pending == s->pending_buf_size) { alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: flush_pending(strm); alpar@9: beg = s->pending; alpar@9: if (s->pending == s->pending_buf_size) alpar@9: break; alpar@9: } alpar@9: put_byte(s, s->gzhead->extra[s->gzindex]); alpar@9: s->gzindex++; alpar@9: } alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: if (s->gzindex == s->gzhead->extra_len) { alpar@9: s->gzindex = 0; alpar@9: s->status = NAME_STATE; alpar@9: } alpar@9: } alpar@9: else alpar@9: s->status = NAME_STATE; alpar@9: } alpar@9: if (s->status == NAME_STATE) { alpar@9: if (s->gzhead->name != Z_NULL) { alpar@9: uInt beg = s->pending; /* start of bytes to update crc */ alpar@9: int val; alpar@9: alpar@9: do { alpar@9: if (s->pending == s->pending_buf_size) { alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: flush_pending(strm); alpar@9: beg = s->pending; alpar@9: if (s->pending == s->pending_buf_size) { alpar@9: val = 1; alpar@9: break; alpar@9: } alpar@9: } alpar@9: val = s->gzhead->name[s->gzindex++]; alpar@9: put_byte(s, val); alpar@9: } while (val != 0); alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: if (val == 0) { alpar@9: s->gzindex = 0; alpar@9: s->status = COMMENT_STATE; alpar@9: } alpar@9: } alpar@9: else alpar@9: s->status = COMMENT_STATE; alpar@9: } alpar@9: if (s->status == COMMENT_STATE) { alpar@9: if (s->gzhead->comment != Z_NULL) { alpar@9: uInt beg = s->pending; /* start of bytes to update crc */ alpar@9: int val; alpar@9: alpar@9: do { alpar@9: if (s->pending == s->pending_buf_size) { alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: flush_pending(strm); alpar@9: beg = s->pending; alpar@9: if (s->pending == s->pending_buf_size) { alpar@9: val = 1; alpar@9: break; alpar@9: } alpar@9: } alpar@9: val = s->gzhead->comment[s->gzindex++]; alpar@9: put_byte(s, val); alpar@9: } while (val != 0); alpar@9: if (s->gzhead->hcrc && s->pending > beg) alpar@9: strm->adler = crc32(strm->adler, s->pending_buf + beg, alpar@9: s->pending - beg); alpar@9: if (val == 0) alpar@9: s->status = HCRC_STATE; alpar@9: } alpar@9: else alpar@9: s->status = HCRC_STATE; alpar@9: } alpar@9: if (s->status == HCRC_STATE) { alpar@9: if (s->gzhead->hcrc) { alpar@9: if (s->pending + 2 > s->pending_buf_size) alpar@9: flush_pending(strm); alpar@9: if (s->pending + 2 <= s->pending_buf_size) { alpar@9: put_byte(s, (Byte)(strm->adler & 0xff)); alpar@9: put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); alpar@9: strm->adler = crc32(0L, Z_NULL, 0); alpar@9: s->status = BUSY_STATE; alpar@9: } alpar@9: } alpar@9: else alpar@9: s->status = BUSY_STATE; alpar@9: } alpar@9: #endif alpar@9: alpar@9: /* Flush as much pending output as possible */ alpar@9: if (s->pending != 0) { alpar@9: flush_pending(strm); alpar@9: if (strm->avail_out == 0) { alpar@9: /* Since avail_out is 0, deflate will be called again with alpar@9: * more output space, but possibly with both pending and alpar@9: * avail_in equal to zero. There won't be anything to do, alpar@9: * but this is not an error situation so make sure we alpar@9: * return OK instead of BUF_ERROR at next call of deflate: alpar@9: */ alpar@9: s->last_flush = -1; alpar@9: return Z_OK; alpar@9: } alpar@9: alpar@9: /* Make sure there is something to do and avoid duplicate consecutive alpar@9: * flushes. For repeated and useless calls with Z_FINISH, we keep alpar@9: * returning Z_STREAM_END instead of Z_BUF_ERROR. alpar@9: */ alpar@9: } else if (strm->avail_in == 0 && flush <= old_flush && alpar@9: flush != Z_FINISH) { alpar@9: ERR_RETURN(strm, Z_BUF_ERROR); alpar@9: } alpar@9: alpar@9: /* User must not provide more input after the first FINISH: */ alpar@9: if (s->status == FINISH_STATE && strm->avail_in != 0) { alpar@9: ERR_RETURN(strm, Z_BUF_ERROR); alpar@9: } alpar@9: alpar@9: /* Start a new block or continue the current one. alpar@9: */ alpar@9: if (strm->avail_in != 0 || s->lookahead != 0 || alpar@9: (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { alpar@9: block_state bstate; alpar@9: alpar@9: bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : alpar@9: (s->strategy == Z_RLE ? deflate_rle(s, flush) : alpar@9: (*(configuration_table[s->level].func))(s, flush)); alpar@9: alpar@9: if (bstate == finish_started || bstate == finish_done) { alpar@9: s->status = FINISH_STATE; alpar@9: } alpar@9: if (bstate == need_more || bstate == finish_started) { alpar@9: if (strm->avail_out == 0) { alpar@9: s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ alpar@9: } alpar@9: return Z_OK; alpar@9: /* If flush != Z_NO_FLUSH && avail_out == 0, the next call alpar@9: * of deflate should use the same flush parameter to make sure alpar@9: * that the flush is complete. So we don't have to output an alpar@9: * empty block here, this will be done at next call. This also alpar@9: * ensures that for a very small output buffer, we emit at most alpar@9: * one empty block. alpar@9: */ alpar@9: } alpar@9: if (bstate == block_done) { alpar@9: if (flush == Z_PARTIAL_FLUSH) { alpar@9: _tr_align(s); alpar@9: } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ alpar@9: _tr_stored_block(s, (char*)0, 0L, 0); alpar@9: /* For a full flush, this empty block will be recognized alpar@9: * as a special marker by inflate_sync(). alpar@9: */ alpar@9: if (flush == Z_FULL_FLUSH) { alpar@9: CLEAR_HASH(s); /* forget history */ alpar@9: if (s->lookahead == 0) { alpar@9: s->strstart = 0; alpar@9: s->block_start = 0L; alpar@9: } alpar@9: } alpar@9: } alpar@9: flush_pending(strm); alpar@9: if (strm->avail_out == 0) { alpar@9: s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ alpar@9: return Z_OK; alpar@9: } alpar@9: } alpar@9: } alpar@9: Assert(strm->avail_out > 0, "bug2"); alpar@9: alpar@9: if (flush != Z_FINISH) return Z_OK; alpar@9: if (s->wrap <= 0) return Z_STREAM_END; alpar@9: alpar@9: /* Write the trailer */ alpar@9: #ifdef GZIP alpar@9: if (s->wrap == 2) { alpar@9: put_byte(s, (Byte)(strm->adler & 0xff)); alpar@9: put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); alpar@9: put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); alpar@9: put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); alpar@9: put_byte(s, (Byte)(strm->total_in & 0xff)); alpar@9: put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); alpar@9: put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); alpar@9: put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); alpar@9: } alpar@9: else alpar@9: #endif alpar@9: { alpar@9: putShortMSB(s, (uInt)(strm->adler >> 16)); alpar@9: putShortMSB(s, (uInt)(strm->adler & 0xffff)); alpar@9: } alpar@9: flush_pending(strm); alpar@9: /* If avail_out is zero, the application will call deflate again alpar@9: * to flush the rest. alpar@9: */ alpar@9: if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ alpar@9: return s->pending != 0 ? Z_OK : Z_STREAM_END; alpar@9: } alpar@9: alpar@9: /* ========================================================================= */ alpar@9: int ZEXPORT deflateEnd (strm) alpar@9: z_streamp strm; alpar@9: { alpar@9: int status; alpar@9: alpar@9: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; alpar@9: alpar@9: status = strm->state->status; alpar@9: if (status != INIT_STATE && alpar@9: status != EXTRA_STATE && alpar@9: status != NAME_STATE && alpar@9: status != COMMENT_STATE && alpar@9: status != HCRC_STATE && alpar@9: status != BUSY_STATE && alpar@9: status != FINISH_STATE) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: alpar@9: /* Deallocate in reverse order of allocations: */ alpar@9: TRY_FREE(strm, strm->state->pending_buf); alpar@9: TRY_FREE(strm, strm->state->head); alpar@9: TRY_FREE(strm, strm->state->prev); alpar@9: TRY_FREE(strm, strm->state->window); alpar@9: alpar@9: ZFREE(strm, strm->state); alpar@9: strm->state = Z_NULL; alpar@9: alpar@9: return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; alpar@9: } alpar@9: alpar@9: /* ========================================================================= alpar@9: * Copy the source state to the destination state. alpar@9: * To simplify the source, this is not supported for 16-bit MSDOS (which alpar@9: * doesn't have enough memory anyway to duplicate compression states). alpar@9: */ alpar@9: int ZEXPORT deflateCopy (dest, source) alpar@9: z_streamp dest; alpar@9: z_streamp source; alpar@9: { alpar@9: #ifdef MAXSEG_64K alpar@9: return Z_STREAM_ERROR; alpar@9: #else alpar@9: deflate_state *ds; alpar@9: deflate_state *ss; alpar@9: ushf *overlay; alpar@9: alpar@9: alpar@9: if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { alpar@9: return Z_STREAM_ERROR; alpar@9: } alpar@9: alpar@9: ss = source->state; alpar@9: alpar@9: zmemcpy(dest, source, sizeof(z_stream)); alpar@9: alpar@9: ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); alpar@9: if (ds == Z_NULL) return Z_MEM_ERROR; alpar@9: dest->state = (struct internal_state FAR *) ds; alpar@9: zmemcpy(ds, ss, sizeof(deflate_state)); alpar@9: ds->strm = dest; alpar@9: alpar@9: ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); alpar@9: ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); alpar@9: ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); alpar@9: overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); alpar@9: ds->pending_buf = (uchf *) overlay; alpar@9: alpar@9: if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || alpar@9: ds->pending_buf == Z_NULL) { alpar@9: deflateEnd (dest); alpar@9: return Z_MEM_ERROR; alpar@9: } alpar@9: /* following zmemcpy do not work for 16-bit MSDOS */ alpar@9: zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); alpar@9: zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); alpar@9: zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); alpar@9: zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); alpar@9: alpar@9: ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); alpar@9: ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); alpar@9: ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; alpar@9: alpar@9: ds->l_desc.dyn_tree = ds->dyn_ltree; alpar@9: ds->d_desc.dyn_tree = ds->dyn_dtree; alpar@9: ds->bl_desc.dyn_tree = ds->bl_tree; alpar@9: alpar@9: return Z_OK; alpar@9: #endif /* MAXSEG_64K */ alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * Read a new buffer from the current input stream, update the adler32 alpar@9: * and total number of bytes read. All deflate() input goes through alpar@9: * this function so some applications may wish to modify it to avoid alpar@9: * allocating a large strm->next_in buffer and copying from it. alpar@9: * (See also flush_pending()). alpar@9: */ alpar@9: local int read_buf(strm, buf, size) alpar@9: z_streamp strm; alpar@9: Bytef *buf; alpar@9: unsigned size; alpar@9: { alpar@9: unsigned len = strm->avail_in; alpar@9: alpar@9: if (len > size) len = size; alpar@9: if (len == 0) return 0; alpar@9: alpar@9: strm->avail_in -= len; alpar@9: alpar@9: if (strm->state->wrap == 1) { alpar@9: strm->adler = adler32(strm->adler, strm->next_in, len); alpar@9: } alpar@9: #ifdef GZIP alpar@9: else if (strm->state->wrap == 2) { alpar@9: strm->adler = crc32(strm->adler, strm->next_in, len); alpar@9: } alpar@9: #endif alpar@9: zmemcpy(buf, strm->next_in, len); alpar@9: strm->next_in += len; alpar@9: strm->total_in += len; alpar@9: alpar@9: return (int)len; alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * Initialize the "longest match" routines for a new zlib stream alpar@9: */ alpar@9: local void lm_init (s) alpar@9: deflate_state *s; alpar@9: { alpar@9: s->window_size = (ulg)2L*s->w_size; alpar@9: alpar@9: CLEAR_HASH(s); alpar@9: alpar@9: /* Set the default configuration parameters: alpar@9: */ alpar@9: s->max_lazy_match = configuration_table[s->level].max_lazy; alpar@9: s->good_match = configuration_table[s->level].good_length; alpar@9: s->nice_match = configuration_table[s->level].nice_length; alpar@9: s->max_chain_length = configuration_table[s->level].max_chain; alpar@9: alpar@9: s->strstart = 0; alpar@9: s->block_start = 0L; alpar@9: s->lookahead = 0; alpar@9: s->match_length = s->prev_length = MIN_MATCH-1; alpar@9: s->match_available = 0; alpar@9: s->ins_h = 0; alpar@9: #ifndef FASTEST alpar@9: #ifdef ASMV alpar@9: match_init(); /* initialize the asm code */ alpar@9: #endif alpar@9: #endif alpar@9: } alpar@9: alpar@9: #ifndef FASTEST alpar@9: /* =========================================================================== alpar@9: * Set match_start to the longest match starting at the given string and alpar@9: * return its length. Matches shorter or equal to prev_length are discarded, alpar@9: * in which case the result is equal to prev_length and match_start is alpar@9: * garbage. alpar@9: * IN assertions: cur_match is the head of the hash chain for the current alpar@9: * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 alpar@9: * OUT assertion: the match length is not greater than s->lookahead. alpar@9: */ alpar@9: #ifndef ASMV alpar@9: /* For 80x86 and 680x0, an optimized version will be provided in match.asm or alpar@9: * match.S. The code will be functionally equivalent. alpar@9: */ alpar@9: local uInt longest_match(s, cur_match) alpar@9: deflate_state *s; alpar@9: IPos cur_match; /* current match */ alpar@9: { alpar@9: unsigned chain_length = s->max_chain_length;/* max hash chain length */ alpar@9: register Bytef *scan = s->window + s->strstart; /* current string */ alpar@9: register Bytef *match; /* matched string */ alpar@9: register int len; /* length of current match */ alpar@9: int best_len = s->prev_length; /* best match length so far */ alpar@9: int nice_match = s->nice_match; /* stop if match long enough */ alpar@9: IPos limit = s->strstart > (IPos)MAX_DIST(s) ? alpar@9: s->strstart - (IPos)MAX_DIST(s) : NIL; alpar@9: /* Stop when cur_match becomes <= limit. To simplify the code, alpar@9: * we prevent matches with the string of window index 0. alpar@9: */ alpar@9: Posf *prev = s->prev; alpar@9: uInt wmask = s->w_mask; alpar@9: alpar@9: #ifdef UNALIGNED_OK alpar@9: /* Compare two bytes at a time. Note: this is not always beneficial. alpar@9: * Try with and without -DUNALIGNED_OK to check. alpar@9: */ alpar@9: register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; alpar@9: register ush scan_start = *(ushf*)scan; alpar@9: register ush scan_end = *(ushf*)(scan+best_len-1); alpar@9: #else alpar@9: register Bytef *strend = s->window + s->strstart + MAX_MATCH; alpar@9: register Byte scan_end1 = scan[best_len-1]; alpar@9: register Byte scan_end = scan[best_len]; alpar@9: #endif alpar@9: alpar@9: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. alpar@9: * It is easy to get rid of this optimization if necessary. alpar@9: */ alpar@9: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); alpar@9: alpar@9: /* Do not waste too much time if we already have a good match: */ alpar@9: if (s->prev_length >= s->good_match) { alpar@9: chain_length >>= 2; alpar@9: } alpar@9: /* Do not look for matches beyond the end of the input. This is necessary alpar@9: * to make deflate deterministic. alpar@9: */ alpar@9: if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; alpar@9: alpar@9: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); alpar@9: alpar@9: do { alpar@9: Assert(cur_match < s->strstart, "no future"); alpar@9: match = s->window + cur_match; alpar@9: alpar@9: /* Skip to next match if the match length cannot increase alpar@9: * or if the match length is less than 2. Note that the checks below alpar@9: * for insufficient lookahead only occur occasionally for performance alpar@9: * reasons. Therefore uninitialized memory will be accessed, and alpar@9: * conditional jumps will be made that depend on those values. alpar@9: * However the length of the match is limited to the lookahead, so alpar@9: * the output of deflate is not affected by the uninitialized values. alpar@9: */ alpar@9: #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) alpar@9: /* This code assumes sizeof(unsigned short) == 2. Do not use alpar@9: * UNALIGNED_OK if your compiler uses a different size. alpar@9: */ alpar@9: if (*(ushf*)(match+best_len-1) != scan_end || alpar@9: *(ushf*)match != scan_start) continue; alpar@9: alpar@9: /* It is not necessary to compare scan[2] and match[2] since they are alpar@9: * always equal when the other bytes match, given that the hash keys alpar@9: * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at alpar@9: * strstart+3, +5, ... up to strstart+257. We check for insufficient alpar@9: * lookahead only every 4th comparison; the 128th check will be made alpar@9: * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is alpar@9: * necessary to put more guard bytes at the end of the window, or alpar@9: * to check more often for insufficient lookahead. alpar@9: */ alpar@9: Assert(scan[2] == match[2], "scan[2]?"); alpar@9: scan++, match++; alpar@9: do { alpar@9: } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && alpar@9: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && alpar@9: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && alpar@9: *(ushf*)(scan+=2) == *(ushf*)(match+=2) && alpar@9: scan < strend); alpar@9: /* The funny "do {}" generates better code on most compilers */ alpar@9: alpar@9: /* Here, scan <= window+strstart+257 */ alpar@9: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); alpar@9: if (*scan == *match) scan++; alpar@9: alpar@9: len = (MAX_MATCH - 1) - (int)(strend-scan); alpar@9: scan = strend - (MAX_MATCH-1); alpar@9: alpar@9: #else /* UNALIGNED_OK */ alpar@9: alpar@9: if (match[best_len] != scan_end || alpar@9: match[best_len-1] != scan_end1 || alpar@9: *match != *scan || alpar@9: *++match != scan[1]) continue; alpar@9: alpar@9: /* The check at best_len-1 can be removed because it will be made alpar@9: * again later. (This heuristic is not always a win.) alpar@9: * It is not necessary to compare scan[2] and match[2] since they alpar@9: * are always equal when the other bytes match, given that alpar@9: * the hash keys are equal and that HASH_BITS >= 8. alpar@9: */ alpar@9: scan += 2, match++; alpar@9: Assert(*scan == *match, "match[2]?"); alpar@9: alpar@9: /* We check for insufficient lookahead only every 8th comparison; alpar@9: * the 256th check will be made at strstart+258. alpar@9: */ alpar@9: do { alpar@9: } while (*++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: scan < strend); alpar@9: alpar@9: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); alpar@9: alpar@9: len = MAX_MATCH - (int)(strend - scan); alpar@9: scan = strend - MAX_MATCH; alpar@9: alpar@9: #endif /* UNALIGNED_OK */ alpar@9: alpar@9: if (len > best_len) { alpar@9: s->match_start = cur_match; alpar@9: best_len = len; alpar@9: if (len >= nice_match) break; alpar@9: #ifdef UNALIGNED_OK alpar@9: scan_end = *(ushf*)(scan+best_len-1); alpar@9: #else alpar@9: scan_end1 = scan[best_len-1]; alpar@9: scan_end = scan[best_len]; alpar@9: #endif alpar@9: } alpar@9: } while ((cur_match = prev[cur_match & wmask]) > limit alpar@9: && --chain_length != 0); alpar@9: alpar@9: if ((uInt)best_len <= s->lookahead) return (uInt)best_len; alpar@9: return s->lookahead; alpar@9: } alpar@9: #endif /* ASMV */ alpar@9: alpar@9: #else /* FASTEST */ alpar@9: alpar@9: /* --------------------------------------------------------------------------- alpar@9: * Optimized version for FASTEST only alpar@9: */ alpar@9: local uInt longest_match(s, cur_match) alpar@9: deflate_state *s; alpar@9: IPos cur_match; /* current match */ alpar@9: { alpar@9: register Bytef *scan = s->window + s->strstart; /* current string */ alpar@9: register Bytef *match; /* matched string */ alpar@9: register int len; /* length of current match */ alpar@9: register Bytef *strend = s->window + s->strstart + MAX_MATCH; alpar@9: alpar@9: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. alpar@9: * It is easy to get rid of this optimization if necessary. alpar@9: */ alpar@9: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); alpar@9: alpar@9: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); alpar@9: alpar@9: Assert(cur_match < s->strstart, "no future"); alpar@9: alpar@9: match = s->window + cur_match; alpar@9: alpar@9: /* Return failure if the match length is less than 2: alpar@9: */ alpar@9: if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; alpar@9: alpar@9: /* The check at best_len-1 can be removed because it will be made alpar@9: * again later. (This heuristic is not always a win.) alpar@9: * It is not necessary to compare scan[2] and match[2] since they alpar@9: * are always equal when the other bytes match, given that alpar@9: * the hash keys are equal and that HASH_BITS >= 8. alpar@9: */ alpar@9: scan += 2, match += 2; alpar@9: Assert(*scan == *match, "match[2]?"); alpar@9: alpar@9: /* We check for insufficient lookahead only every 8th comparison; alpar@9: * the 256th check will be made at strstart+258. alpar@9: */ alpar@9: do { alpar@9: } while (*++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: *++scan == *++match && *++scan == *++match && alpar@9: scan < strend); alpar@9: alpar@9: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); alpar@9: alpar@9: len = MAX_MATCH - (int)(strend - scan); alpar@9: alpar@9: if (len < MIN_MATCH) return MIN_MATCH - 1; alpar@9: alpar@9: s->match_start = cur_match; alpar@9: return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; alpar@9: } alpar@9: alpar@9: #endif /* FASTEST */ alpar@9: alpar@9: #ifdef DEBUG alpar@9: /* =========================================================================== alpar@9: * Check that the match at match_start is indeed a match. alpar@9: */ alpar@9: local void check_match(s, start, match, length) alpar@9: deflate_state *s; alpar@9: IPos start, match; alpar@9: int length; alpar@9: { alpar@9: /* check that the match is indeed a match */ alpar@9: if (zmemcmp(s->window + match, alpar@9: s->window + start, length) != EQUAL) { alpar@9: fprintf(stderr, " start %u, match %u, length %d\n", alpar@9: start, match, length); alpar@9: do { alpar@9: fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); alpar@9: } while (--length != 0); alpar@9: z_error("invalid match"); alpar@9: } alpar@9: if (z_verbose > 1) { alpar@9: fprintf(stderr,"\\[%d,%d]", start-match, length); alpar@9: do { putc(s->window[start++], stderr); } while (--length != 0); alpar@9: } alpar@9: } alpar@9: #else alpar@9: # define check_match(s, start, match, length) alpar@9: #endif /* DEBUG */ alpar@9: alpar@9: /* =========================================================================== alpar@9: * Fill the window when the lookahead becomes insufficient. alpar@9: * Updates strstart and lookahead. alpar@9: * alpar@9: * IN assertion: lookahead < MIN_LOOKAHEAD alpar@9: * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD alpar@9: * At least one byte has been read, or avail_in == 0; reads are alpar@9: * performed for at least two bytes (required for the zip translate_eol alpar@9: * option -- not supported here). alpar@9: */ alpar@9: local void fill_window(s) alpar@9: deflate_state *s; alpar@9: { alpar@9: register unsigned n, m; alpar@9: register Posf *p; alpar@9: unsigned more; /* Amount of free space at the end of the window. */ alpar@9: uInt wsize = s->w_size; alpar@9: alpar@9: do { alpar@9: more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); alpar@9: alpar@9: /* Deal with !@#$% 64K limit: */ alpar@9: if (sizeof(int) <= 2) { alpar@9: if (more == 0 && s->strstart == 0 && s->lookahead == 0) { alpar@9: more = wsize; alpar@9: alpar@9: } else if (more == (unsigned)(-1)) { alpar@9: /* Very unlikely, but possible on 16 bit machine if alpar@9: * strstart == 0 && lookahead == 1 (input done a byte at time) alpar@9: */ alpar@9: more--; alpar@9: } alpar@9: } alpar@9: alpar@9: /* If the window is almost full and there is insufficient lookahead, alpar@9: * move the upper half to the lower one to make room in the upper half. alpar@9: */ alpar@9: if (s->strstart >= wsize+MAX_DIST(s)) { alpar@9: alpar@9: zmemcpy(s->window, s->window+wsize, (unsigned)wsize); alpar@9: s->match_start -= wsize; alpar@9: s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ alpar@9: s->block_start -= (long) wsize; alpar@9: alpar@9: /* Slide the hash table (could be avoided with 32 bit values alpar@9: at the expense of memory usage). We slide even when level == 0 alpar@9: to keep the hash table consistent if we switch back to level > 0 alpar@9: later. (Using level 0 permanently is not an optimal usage of alpar@9: zlib, so we don't care about this pathological case.) alpar@9: */ alpar@9: n = s->hash_size; alpar@9: p = &s->head[n]; alpar@9: do { alpar@9: m = *--p; alpar@9: *p = (Pos)(m >= wsize ? m-wsize : NIL); alpar@9: } while (--n); alpar@9: alpar@9: n = wsize; alpar@9: #ifndef FASTEST alpar@9: p = &s->prev[n]; alpar@9: do { alpar@9: m = *--p; alpar@9: *p = (Pos)(m >= wsize ? m-wsize : NIL); alpar@9: /* If n is not on any hash chain, prev[n] is garbage but alpar@9: * its value will never be used. alpar@9: */ alpar@9: } while (--n); alpar@9: #endif alpar@9: more += wsize; alpar@9: } alpar@9: if (s->strm->avail_in == 0) return; alpar@9: alpar@9: /* If there was no sliding: alpar@9: * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && alpar@9: * more == window_size - lookahead - strstart alpar@9: * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) alpar@9: * => more >= window_size - 2*WSIZE + 2 alpar@9: * In the BIG_MEM or MMAP case (not yet supported), alpar@9: * window_size == input_size + MIN_LOOKAHEAD && alpar@9: * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. alpar@9: * Otherwise, window_size == 2*WSIZE so more >= 2. alpar@9: * If there was sliding, more >= WSIZE. So in all cases, more >= 2. alpar@9: */ alpar@9: Assert(more >= 2, "more < 2"); alpar@9: alpar@9: n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); alpar@9: s->lookahead += n; alpar@9: alpar@9: /* Initialize the hash value now that we have some input: */ alpar@9: if (s->lookahead >= MIN_MATCH) { alpar@9: s->ins_h = s->window[s->strstart]; alpar@9: UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); alpar@9: #if MIN_MATCH != 3 alpar@9: Call UPDATE_HASH() MIN_MATCH-3 more times alpar@9: #endif alpar@9: } alpar@9: /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, alpar@9: * but this is not important since only literal bytes will be emitted. alpar@9: */ alpar@9: alpar@9: } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); alpar@9: alpar@9: /* If the WIN_INIT bytes after the end of the current data have never been alpar@9: * written, then zero those bytes in order to avoid memory check reports of alpar@9: * the use of uninitialized (or uninitialised as Julian writes) bytes by alpar@9: * the longest match routines. Update the high water mark for the next alpar@9: * time through here. WIN_INIT is set to MAX_MATCH since the longest match alpar@9: * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. alpar@9: */ alpar@9: if (s->high_water < s->window_size) { alpar@9: ulg curr = s->strstart + (ulg)(s->lookahead); alpar@9: ulg init; alpar@9: alpar@9: if (s->high_water < curr) { alpar@9: /* Previous high water mark below current data -- zero WIN_INIT alpar@9: * bytes or up to end of window, whichever is less. alpar@9: */ alpar@9: init = s->window_size - curr; alpar@9: if (init > WIN_INIT) alpar@9: init = WIN_INIT; alpar@9: zmemzero(s->window + curr, (unsigned)init); alpar@9: s->high_water = curr + init; alpar@9: } alpar@9: else if (s->high_water < (ulg)curr + WIN_INIT) { alpar@9: /* High water mark at or above current data, but below current data alpar@9: * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up alpar@9: * to end of window, whichever is less. alpar@9: */ alpar@9: init = (ulg)curr + WIN_INIT - s->high_water; alpar@9: if (init > s->window_size - s->high_water) alpar@9: init = s->window_size - s->high_water; alpar@9: zmemzero(s->window + s->high_water, (unsigned)init); alpar@9: s->high_water += init; alpar@9: } alpar@9: } alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * Flush the current block, with given end-of-file flag. alpar@9: * IN assertion: strstart is set to the end of the current match. alpar@9: */ alpar@9: #define FLUSH_BLOCK_ONLY(s, last) { \ alpar@9: _tr_flush_block(s, (s->block_start >= 0L ? \ alpar@9: (charf *)&s->window[(unsigned)s->block_start] : \ alpar@9: (charf *)Z_NULL), \ alpar@9: (ulg)((long)s->strstart - s->block_start), \ alpar@9: (last)); \ alpar@9: s->block_start = s->strstart; \ alpar@9: flush_pending(s->strm); \ alpar@9: Tracev((stderr,"[FLUSH]")); \ alpar@9: } alpar@9: alpar@9: /* Same but force premature exit if necessary. */ alpar@9: #define FLUSH_BLOCK(s, last) { \ alpar@9: FLUSH_BLOCK_ONLY(s, last); \ alpar@9: if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * Copy without compression as much as possible from the input stream, return alpar@9: * the current block state. alpar@9: * This function does not insert new strings in the dictionary since alpar@9: * uncompressible data is probably not useful. This function is used alpar@9: * only for the level=0 compression option. alpar@9: * NOTE: this function should be optimized to avoid extra copying from alpar@9: * window to pending_buf. alpar@9: */ alpar@9: local block_state deflate_stored(s, flush) alpar@9: deflate_state *s; alpar@9: int flush; alpar@9: { alpar@9: /* Stored blocks are limited to 0xffff bytes, pending_buf is limited alpar@9: * to pending_buf_size, and each stored block has a 5 byte header: alpar@9: */ alpar@9: ulg max_block_size = 0xffff; alpar@9: ulg max_start; alpar@9: alpar@9: if (max_block_size > s->pending_buf_size - 5) { alpar@9: max_block_size = s->pending_buf_size - 5; alpar@9: } alpar@9: alpar@9: /* Copy as much as possible from input to output: */ alpar@9: for (;;) { alpar@9: /* Fill the window as much as possible: */ alpar@9: if (s->lookahead <= 1) { alpar@9: alpar@9: Assert(s->strstart < s->w_size+MAX_DIST(s) || alpar@9: s->block_start >= (long)s->w_size, "slide too late"); alpar@9: alpar@9: fill_window(s); alpar@9: if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; alpar@9: alpar@9: if (s->lookahead == 0) break; /* flush the current block */ alpar@9: } alpar@9: Assert(s->block_start >= 0L, "block gone"); alpar@9: alpar@9: s->strstart += s->lookahead; alpar@9: s->lookahead = 0; alpar@9: alpar@9: /* Emit a stored block if pending_buf will be full: */ alpar@9: max_start = s->block_start + max_block_size; alpar@9: if (s->strstart == 0 || (ulg)s->strstart >= max_start) { alpar@9: /* strstart == 0 is possible when wraparound on 16-bit machine */ alpar@9: s->lookahead = (uInt)(s->strstart - max_start); alpar@9: s->strstart = (uInt)max_start; alpar@9: FLUSH_BLOCK(s, 0); alpar@9: } alpar@9: /* Flush if we may have to slide, otherwise block_start may become alpar@9: * negative and the data will be gone: alpar@9: */ alpar@9: if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { alpar@9: FLUSH_BLOCK(s, 0); alpar@9: } alpar@9: } alpar@9: FLUSH_BLOCK(s, flush == Z_FINISH); alpar@9: return flush == Z_FINISH ? finish_done : block_done; alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * Compress as much as possible from the input stream, return the current alpar@9: * block state. alpar@9: * This function does not perform lazy evaluation of matches and inserts alpar@9: * new strings in the dictionary only for unmatched strings or for short alpar@9: * matches. It is used only for the fast compression options. alpar@9: */ alpar@9: local block_state deflate_fast(s, flush) alpar@9: deflate_state *s; alpar@9: int flush; alpar@9: { alpar@9: IPos hash_head; /* head of the hash chain */ alpar@9: int bflush; /* set if current block must be flushed */ alpar@9: alpar@9: for (;;) { alpar@9: /* Make sure that we always have enough lookahead, except alpar@9: * at the end of the input file. We need MAX_MATCH bytes alpar@9: * for the next match, plus MIN_MATCH bytes to insert the alpar@9: * string following the next match. alpar@9: */ alpar@9: if (s->lookahead < MIN_LOOKAHEAD) { alpar@9: fill_window(s); alpar@9: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { alpar@9: return need_more; alpar@9: } alpar@9: if (s->lookahead == 0) break; /* flush the current block */ alpar@9: } alpar@9: alpar@9: /* Insert the string window[strstart .. strstart+2] in the alpar@9: * dictionary, and set hash_head to the head of the hash chain: alpar@9: */ alpar@9: hash_head = NIL; alpar@9: if (s->lookahead >= MIN_MATCH) { alpar@9: INSERT_STRING(s, s->strstart, hash_head); alpar@9: } alpar@9: alpar@9: /* Find the longest match, discarding those <= prev_length. alpar@9: * At this point we have always match_length < MIN_MATCH alpar@9: */ alpar@9: if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { alpar@9: /* To simplify the code, we prevent matches with the string alpar@9: * of window index 0 (in particular we have to avoid a match alpar@9: * of the string with itself at the start of the input file). alpar@9: */ alpar@9: s->match_length = longest_match (s, hash_head); alpar@9: /* longest_match() sets match_start */ alpar@9: } alpar@9: if (s->match_length >= MIN_MATCH) { alpar@9: check_match(s, s->strstart, s->match_start, s->match_length); alpar@9: alpar@9: _tr_tally_dist(s, s->strstart - s->match_start, alpar@9: s->match_length - MIN_MATCH, bflush); alpar@9: alpar@9: s->lookahead -= s->match_length; alpar@9: alpar@9: /* Insert new strings in the hash table only if the match length alpar@9: * is not too large. This saves time but degrades compression. alpar@9: */ alpar@9: #ifndef FASTEST alpar@9: if (s->match_length <= s->max_insert_length && alpar@9: s->lookahead >= MIN_MATCH) { alpar@9: s->match_length--; /* string at strstart already in table */ alpar@9: do { alpar@9: s->strstart++; alpar@9: INSERT_STRING(s, s->strstart, hash_head); alpar@9: /* strstart never exceeds WSIZE-MAX_MATCH, so there are alpar@9: * always MIN_MATCH bytes ahead. alpar@9: */ alpar@9: } while (--s->match_length != 0); alpar@9: s->strstart++; alpar@9: } else alpar@9: #endif alpar@9: { alpar@9: s->strstart += s->match_length; alpar@9: s->match_length = 0; alpar@9: s->ins_h = s->window[s->strstart]; alpar@9: UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); alpar@9: #if MIN_MATCH != 3 alpar@9: Call UPDATE_HASH() MIN_MATCH-3 more times alpar@9: #endif alpar@9: /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not alpar@9: * matter since it will be recomputed at next deflate call. alpar@9: */ alpar@9: } alpar@9: } else { alpar@9: /* No match, output a literal byte */ alpar@9: Tracevv((stderr,"%c", s->window[s->strstart])); alpar@9: _tr_tally_lit (s, s->window[s->strstart], bflush); alpar@9: s->lookahead--; alpar@9: s->strstart++; alpar@9: } alpar@9: if (bflush) FLUSH_BLOCK(s, 0); alpar@9: } alpar@9: FLUSH_BLOCK(s, flush == Z_FINISH); alpar@9: return flush == Z_FINISH ? finish_done : block_done; alpar@9: } alpar@9: alpar@9: #ifndef FASTEST alpar@9: /* =========================================================================== alpar@9: * Same as above, but achieves better compression. We use a lazy alpar@9: * evaluation for matches: a match is finally adopted only if there is alpar@9: * no better match at the next window position. alpar@9: */ alpar@9: local block_state deflate_slow(s, flush) alpar@9: deflate_state *s; alpar@9: int flush; alpar@9: { alpar@9: IPos hash_head; /* head of hash chain */ alpar@9: int bflush; /* set if current block must be flushed */ alpar@9: alpar@9: /* Process the input block. */ alpar@9: for (;;) { alpar@9: /* Make sure that we always have enough lookahead, except alpar@9: * at the end of the input file. We need MAX_MATCH bytes alpar@9: * for the next match, plus MIN_MATCH bytes to insert the alpar@9: * string following the next match. alpar@9: */ alpar@9: if (s->lookahead < MIN_LOOKAHEAD) { alpar@9: fill_window(s); alpar@9: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { alpar@9: return need_more; alpar@9: } alpar@9: if (s->lookahead == 0) break; /* flush the current block */ alpar@9: } alpar@9: alpar@9: /* Insert the string window[strstart .. strstart+2] in the alpar@9: * dictionary, and set hash_head to the head of the hash chain: alpar@9: */ alpar@9: hash_head = NIL; alpar@9: if (s->lookahead >= MIN_MATCH) { alpar@9: INSERT_STRING(s, s->strstart, hash_head); alpar@9: } alpar@9: alpar@9: /* Find the longest match, discarding those <= prev_length. alpar@9: */ alpar@9: s->prev_length = s->match_length, s->prev_match = s->match_start; alpar@9: s->match_length = MIN_MATCH-1; alpar@9: alpar@9: if (hash_head != NIL && s->prev_length < s->max_lazy_match && alpar@9: s->strstart - hash_head <= MAX_DIST(s)) { alpar@9: /* To simplify the code, we prevent matches with the string alpar@9: * of window index 0 (in particular we have to avoid a match alpar@9: * of the string with itself at the start of the input file). alpar@9: */ alpar@9: s->match_length = longest_match (s, hash_head); alpar@9: /* longest_match() sets match_start */ alpar@9: alpar@9: if (s->match_length <= 5 && (s->strategy == Z_FILTERED alpar@9: #if TOO_FAR <= 32767 alpar@9: || (s->match_length == MIN_MATCH && alpar@9: s->strstart - s->match_start > TOO_FAR) alpar@9: #endif alpar@9: )) { alpar@9: alpar@9: /* If prev_match is also MIN_MATCH, match_start is garbage alpar@9: * but we will ignore the current match anyway. alpar@9: */ alpar@9: s->match_length = MIN_MATCH-1; alpar@9: } alpar@9: } alpar@9: /* If there was a match at the previous step and the current alpar@9: * match is not better, output the previous match: alpar@9: */ alpar@9: if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { alpar@9: uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; alpar@9: /* Do not insert strings in hash table beyond this. */ alpar@9: alpar@9: check_match(s, s->strstart-1, s->prev_match, s->prev_length); alpar@9: alpar@9: _tr_tally_dist(s, s->strstart -1 - s->prev_match, alpar@9: s->prev_length - MIN_MATCH, bflush); alpar@9: alpar@9: /* Insert in hash table all strings up to the end of the match. alpar@9: * strstart-1 and strstart are already inserted. If there is not alpar@9: * enough lookahead, the last two strings are not inserted in alpar@9: * the hash table. alpar@9: */ alpar@9: s->lookahead -= s->prev_length-1; alpar@9: s->prev_length -= 2; alpar@9: do { alpar@9: if (++s->strstart <= max_insert) { alpar@9: INSERT_STRING(s, s->strstart, hash_head); alpar@9: } alpar@9: } while (--s->prev_length != 0); alpar@9: s->match_available = 0; alpar@9: s->match_length = MIN_MATCH-1; alpar@9: s->strstart++; alpar@9: alpar@9: if (bflush) FLUSH_BLOCK(s, 0); alpar@9: alpar@9: } else if (s->match_available) { alpar@9: /* If there was no match at the previous position, output a alpar@9: * single literal. If there was a match but the current match alpar@9: * is longer, truncate the previous match to a single literal. alpar@9: */ alpar@9: Tracevv((stderr,"%c", s->window[s->strstart-1])); alpar@9: _tr_tally_lit(s, s->window[s->strstart-1], bflush); alpar@9: if (bflush) { alpar@9: FLUSH_BLOCK_ONLY(s, 0); alpar@9: } alpar@9: s->strstart++; alpar@9: s->lookahead--; alpar@9: if (s->strm->avail_out == 0) return need_more; alpar@9: } else { alpar@9: /* There is no previous match to compare with, wait for alpar@9: * the next step to decide. alpar@9: */ alpar@9: s->match_available = 1; alpar@9: s->strstart++; alpar@9: s->lookahead--; alpar@9: } alpar@9: } alpar@9: Assert (flush != Z_NO_FLUSH, "no flush?"); alpar@9: if (s->match_available) { alpar@9: Tracevv((stderr,"%c", s->window[s->strstart-1])); alpar@9: _tr_tally_lit(s, s->window[s->strstart-1], bflush); alpar@9: s->match_available = 0; alpar@9: } alpar@9: FLUSH_BLOCK(s, flush == Z_FINISH); alpar@9: return flush == Z_FINISH ? finish_done : block_done; alpar@9: } alpar@9: #endif /* FASTEST */ alpar@9: alpar@9: /* =========================================================================== alpar@9: * For Z_RLE, simply look for runs of bytes, generate matches only of distance alpar@9: * one. Do not maintain a hash table. (It will be regenerated if this run of alpar@9: * deflate switches away from Z_RLE.) alpar@9: */ alpar@9: local block_state deflate_rle(s, flush) alpar@9: deflate_state *s; alpar@9: int flush; alpar@9: { alpar@9: int bflush; /* set if current block must be flushed */ alpar@9: uInt prev; /* byte at distance one to match */ alpar@9: Bytef *scan, *strend; /* scan goes up to strend for length of run */ alpar@9: alpar@9: for (;;) { alpar@9: /* Make sure that we always have enough lookahead, except alpar@9: * at the end of the input file. We need MAX_MATCH bytes alpar@9: * for the longest encodable run. alpar@9: */ alpar@9: if (s->lookahead < MAX_MATCH) { alpar@9: fill_window(s); alpar@9: if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { alpar@9: return need_more; alpar@9: } alpar@9: if (s->lookahead == 0) break; /* flush the current block */ alpar@9: } alpar@9: alpar@9: /* See how many times the previous byte repeats */ alpar@9: s->match_length = 0; alpar@9: if (s->lookahead >= MIN_MATCH && s->strstart > 0) { alpar@9: scan = s->window + s->strstart - 1; alpar@9: prev = *scan; alpar@9: if (prev == *++scan && prev == *++scan && prev == *++scan) { alpar@9: strend = s->window + s->strstart + MAX_MATCH; alpar@9: do { alpar@9: } while (prev == *++scan && prev == *++scan && alpar@9: prev == *++scan && prev == *++scan && alpar@9: prev == *++scan && prev == *++scan && alpar@9: prev == *++scan && prev == *++scan && alpar@9: scan < strend); alpar@9: s->match_length = MAX_MATCH - (int)(strend - scan); alpar@9: if (s->match_length > s->lookahead) alpar@9: s->match_length = s->lookahead; alpar@9: } alpar@9: } alpar@9: alpar@9: /* Emit match if have run of MIN_MATCH or longer, else emit literal */ alpar@9: if (s->match_length >= MIN_MATCH) { alpar@9: check_match(s, s->strstart, s->strstart - 1, s->match_length); alpar@9: alpar@9: _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); alpar@9: alpar@9: s->lookahead -= s->match_length; alpar@9: s->strstart += s->match_length; alpar@9: s->match_length = 0; alpar@9: } else { alpar@9: /* No match, output a literal byte */ alpar@9: Tracevv((stderr,"%c", s->window[s->strstart])); alpar@9: _tr_tally_lit (s, s->window[s->strstart], bflush); alpar@9: s->lookahead--; alpar@9: s->strstart++; alpar@9: } alpar@9: if (bflush) FLUSH_BLOCK(s, 0); alpar@9: } alpar@9: FLUSH_BLOCK(s, flush == Z_FINISH); alpar@9: return flush == Z_FINISH ? finish_done : block_done; alpar@9: } alpar@9: alpar@9: /* =========================================================================== alpar@9: * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. alpar@9: * (It will be regenerated if this run of deflate switches away from Huffman.) alpar@9: */ alpar@9: local block_state deflate_huff(s, flush) alpar@9: deflate_state *s; alpar@9: int flush; alpar@9: { alpar@9: int bflush; /* set if current block must be flushed */ alpar@9: alpar@9: for (;;) { alpar@9: /* Make sure that we have a literal to write. */ alpar@9: if (s->lookahead == 0) { alpar@9: fill_window(s); alpar@9: if (s->lookahead == 0) { alpar@9: if (flush == Z_NO_FLUSH) alpar@9: return need_more; alpar@9: break; /* flush the current block */ alpar@9: } alpar@9: } alpar@9: alpar@9: /* Output a literal byte */ alpar@9: s->match_length = 0; alpar@9: Tracevv((stderr,"%c", s->window[s->strstart])); alpar@9: _tr_tally_lit (s, s->window[s->strstart], bflush); alpar@9: s->lookahead--; alpar@9: s->strstart++; alpar@9: if (bflush) FLUSH_BLOCK(s, 0); alpar@9: } alpar@9: FLUSH_BLOCK(s, flush == Z_FINISH); alpar@9: return flush == Z_FINISH ? finish_done : block_done; alpar@9: }