From 965fe72aed580d518c979c9a33b49e7df28205f7 Mon Sep 17 00:00:00 2001 From: Mark Adler Date: Fri, 9 Sep 2011 23:19:55 -0700 Subject: zlib 1.1.0 --- deflate.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 85 insertions(+), 8 deletions(-) (limited to 'deflate.c') diff --git a/deflate.c b/deflate.c index e9c14d7..dc60299 100644 --- a/deflate.c +++ b/deflate.c @@ -52,7 +52,7 @@ #include "deflate.h" const char deflate_copyright[] = - " deflate 1.0.9 Copyright 1995-1998 Jean-loup Gailly "; + " deflate 1.1.0 Copyright 1995-1998 Jean-loup Gailly "; /* If you use the zlib library in a product, an acknowledgment is welcome in the documentation of your product. If for some reason you cannot @@ -160,14 +160,23 @@ struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ * Insert string str in the dictionary and set match_head to the previous head * of the hash chain (the most recent string with same hash key). Return * the previous length of the hash chain. + * If this file is compiled with -DFASTEST, the compression level is forced + * to 1, and no hash chains are maintained. * IN assertion: all calls to to INSERT_STRING are made with consecutive * input characters and the first MIN_MATCH bytes of str are valid * (except for the last MIN_MATCH-1 bytes of the input file). */ +#ifdef FASTEST +#define INSERT_STRING(s, str, match_head) \ + (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ + match_head = s->head[s->ins_h], \ + s->head[s->ins_h] = (Pos)(str)) +#else #define INSERT_STRING(s, str, match_head) \ (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \ s->head[s->ins_h] = (Pos)(str)) +#endif /* =========================================================================== * Initialize the hash table (avoiding 64K overflow for 16 bit systems). @@ -224,6 +233,9 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, if (strm->zfree == Z_NULL) strm->zfree = zcfree; if (level == Z_DEFAULT_COMPRESSION) level = 6; +#ifdef FASTEST + level = 1; +#endif if (windowBits < 0) { /* undocumented feature: suppress zlib header */ noheader = 1; @@ -708,6 +720,7 @@ local void lm_init (s) /* For 80x86 and 680x0, an optimized version will be provided in match.asm or * match.S. The code will be functionally equivalent. */ +#ifndef FASTEST local uInt longest_match(s, cur_match) deflate_state *s; IPos cur_match; /* current match */ @@ -845,6 +858,64 @@ local uInt longest_match(s, cur_match) if ((uInt)best_len <= s->lookahead) return (uInt)best_len; return s->lookahead; } + +#else /* FASTEST */ +/* --------------------------------------------------------------------------- + * Optimized version for level == 1 only + */ +local uInt longest_match(s, cur_match) + deflate_state *s; + IPos cur_match; /* current match */ +{ + register Bytef *scan = s->window + s->strstart; /* current string */ + register Bytef *match; /* matched string */ + register int len; /* length of current match */ + register Bytef *strend = s->window + s->strstart + MAX_MATCH; + + /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. + * It is easy to get rid of this optimization if necessary. + */ + Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); + + Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); + + Assert(cur_match < s->strstart, "no future"); + + match = s->window + cur_match; + + /* Return failure if the match length is less than 2: + */ + if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; + + /* The check at best_len-1 can be removed because it will be made + * again later. (This heuristic is not always a win.) + * It is not necessary to compare scan[2] and match[2] since they + * are always equal when the other bytes match, given that + * the hash keys are equal and that HASH_BITS >= 8. + */ + scan += 2, match += 2; + Assert(*scan == *match, "match[2]?"); + + /* We check for insufficient lookahead only every 8th comparison; + * the 256th check will be made at strstart+258. + */ + do { + } while (*++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + scan < strend); + + Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); + + len = MAX_MATCH - (int)(strend - scan); + + if (len < MIN_MATCH) return MIN_MATCH - 1; + + s->match_start = cur_match; + return len <= s->lookahead ? len : s->lookahead; +} +#endif /* FASTEST */ #endif /* ASMV */ #ifdef DEBUG @@ -930,6 +1001,7 @@ local void fill_window(s) } while (--n); n = wsize; +#ifndef FASTEST p = &s->prev[n]; do { m = *--p; @@ -938,6 +1010,7 @@ local void fill_window(s) * its value will never be used. */ } while (--n); +#endif more += wsize; } if (s->strm->avail_in == 0) return; @@ -1105,14 +1178,15 @@ local block_state deflate_fast(s, flush) if (s->match_length >= MIN_MATCH) { check_match(s, s->strstart, s->match_start, s->match_length); - bflush = _tr_tally(s, s->strstart - s->match_start, - s->match_length - MIN_MATCH); + _tr_tally_dist(s, s->strstart - s->match_start, + s->match_length - MIN_MATCH, bflush); s->lookahead -= s->match_length; /* Insert new strings in the hash table only if the match length * is not too large. This saves time but degrades compression. */ +#ifndef FASTEST if (s->match_length <= s->max_insert_length && s->lookahead >= MIN_MATCH) { s->match_length--; /* string at strstart already in hash table */ @@ -1124,7 +1198,9 @@ local block_state deflate_fast(s, flush) */ } while (--s->match_length != 0); s->strstart++; - } else { + } else +#endif + { s->strstart += s->match_length; s->match_length = 0; s->ins_h = s->window[s->strstart]; @@ -1139,7 +1215,7 @@ local block_state deflate_fast(s, flush) } else { /* No match, output a literal byte */ Tracevv((stderr,"%c", s->window[s->strstart])); - bflush = _tr_tally (s, 0, s->window[s->strstart]); + _tr_tally_lit (s, s->window[s->strstart], bflush); s->lookahead--; s->strstart++; } @@ -1219,7 +1295,7 @@ local block_state deflate_slow(s, flush) check_match(s, s->strstart-1, s->prev_match, s->prev_length); bflush = _tr_tally(s, s->strstart -1 - s->prev_match, - s->prev_length - MIN_MATCH); + s->prev_length - MIN_MATCH); /* Insert in hash table all strings up to the end of the match. * strstart-1 and strstart are already inserted. If there is not @@ -1245,7 +1321,8 @@ local block_state deflate_slow(s, flush) * is longer, truncate the previous match to a single literal. */ Tracevv((stderr,"%c", s->window[s->strstart-1])); - if (_tr_tally (s, 0, s->window[s->strstart-1])) { + _tr_tally_lit(s, s->window[s->strstart-1], bflush); + if (bflush) { FLUSH_BLOCK_ONLY(s, 0); } s->strstart++; @@ -1263,7 +1340,7 @@ local block_state deflate_slow(s, flush) Assert (flush != Z_NO_FLUSH, "no flush?"); if (s->match_available) { Tracevv((stderr,"%c", s->window[s->strstart-1])); - _tr_tally (s, 0, s->window[s->strstart-1]); + _tr_tally_lit(s, s->window[s->strstart-1], bflush); s->match_available = 0; } FLUSH_BLOCK(s, flush == Z_FINISH); -- cgit v1.2.3-55-g6feb