921     IPos hash_head = NIL; /* head of the hash chain */  in deflate_fast()  local
942             INSERT_STRING(s, s->strstart, hash_head);  in deflate_fast()
948         if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {  in deflate_fast()
954                 s->match_length = longest_match (s, hash_head);  in deflate_fast()
974                     INSERT_STRING(s, s->strstart, hash_head);  in deflate_fast()
1015     IPos hash_head = NIL;    /* head of hash chain */  in deflate_slow()  local
1037             INSERT_STRING(s, s->strstart, hash_head);  in deflate_slow()
1045         if (hash_head != NIL && s->prev_length < s->max_lazy_match &&  in deflate_slow()
1046             s->strstart - hash_head <= MAX_DIST(s)) {  in deflate_slow()
1052                 s->match_length = longest_match (s, hash_head);  in deflate_slow()
1087                     INSERT_STRING(s, s->strstart, hash_head);  in deflate_slow()