diff options
| -rw-r--r-- | match_tpl.h | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/match_tpl.h b/match_tpl.h index c8c2cad8e2..f321f700e2 100644 --- a/match_tpl.h +++ b/match_tpl.h @@ -29,20 +29,25 @@ * matches once a match has already been found. */ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { - unsigned int strstart = s->strstart; const unsigned wmask = W_MASK(s); - unsigned char *window = s->window; - unsigned char *scan = window + strstart; - Z_REGISTER unsigned char *mbase_start = window; - Z_REGISTER unsigned char *mbase_end; + unsigned int strstart = s->strstart; + const unsigned char *window = s->window; const Pos *prev = s->prev; +#ifdef LONGEST_MATCH_SLOW + const Pos *head = s->head; +#endif + const unsigned char *scan; + const unsigned char *mbase_start = window; + const unsigned char *mbase_end; Pos limit; #ifdef LONGEST_MATCH_SLOW Pos limit_base; #else int32_t early_exit; #endif - uint32_t chain_length, nice_match, best_len, offset; + uint32_t chain_length = s->max_chain_length; + uint32_t nice_match = (uint32_t)s->nice_match; + uint32_t best_len, offset; uint32_t lookahead = s->lookahead; Pos match_offset = 0; uint64_t scan_start; @@ -51,6 +56,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { /* The code is optimized for STD_MAX_MATCH-2 multiple of 16. */ Assert(STD_MAX_MATCH == 258, "Code too clever"); + scan = window + strstart; best_len = s->prev_length ? s->prev_length : STD_MIN_MATCH-1; /* Calculate read offset which should only extend an extra byte @@ -68,10 +74,8 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { mbase_end = (mbase_start+offset); /* Do not waste too much time if we already have a good match */ - chain_length = s->max_chain_length; if (best_len >= s->good_match) chain_length >>= 2; - nice_match = (uint32_t)s->nice_match; /* Stop when cur_match becomes <= limit. To simplify the code, * we prevent matches with the string of window index 0 @@ -81,7 +85,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { limit_base = limit; if (best_len >= STD_MIN_MATCH) { /* We're continuing search (lazy evaluation). */ - uint32_t i, hash; + uint32_t hash; Pos pos; /* Find a most distant chain starting from scan with index=1 (index=0 corresponds @@ -92,11 +96,11 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { hash = update_hash_roll(0, scan[1]); hash = update_hash_roll(hash, scan[2]); - for (i = 3; i <= best_len; i++) { + for (uint32_t i = 3; i <= best_len; i++) { // use update_hash_roll for deflate_slow hash = update_hash_roll(hash, scan[i]); /* If we're starting with best_len >= 3, we can use offset search. */ - pos = s->head[hash]; + pos = head[hash]; if (pos < cur_match) { match_offset = (Pos)(i - 2); cur_match = pos; @@ -157,9 +161,10 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { /* Do not look for matches beyond the end of the input. */ if (len > lookahead) return lookahead; + if (len >= nice_match) + return len; + best_len = len; - if (best_len >= nice_match) - return best_len; offset = best_len-1; if (best_len >= sizeof(uint32_t)) { @@ -173,15 +178,15 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { #ifdef LONGEST_MATCH_SLOW /* Look for a better string offset */ if (UNLIKELY(len > STD_MIN_MATCH && match_start + len < strstart)) { + const unsigned char *scan_endstr; + uint32_t hash; Pos pos, next_pos; - uint32_t i, hash; - unsigned char *scan_endstr; /* Go back to offset 0 */ cur_match -= match_offset; match_offset = 0; next_pos = cur_match; - for (i = 0; i <= len - STD_MIN_MATCH; i++) { + for (uint32_t i = 0; i <= len - STD_MIN_MATCH; i++) { pos = prev[(cur_match + i) & wmask]; if (pos < next_pos) { /* Hash chain is more distant, use it */ @@ -206,7 +211,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) { hash = update_hash_roll(hash, scan_endstr[1]); hash = update_hash_roll(hash, scan_endstr[2]); - pos = s->head[hash]; + pos = head[hash]; if (pos < cur_match) { match_offset = (Pos)(len - (STD_MIN_MATCH+1)); if (pos <= limit_base + match_offset) |