Author: rjek Date: Sun Aug 20 00:37:58 2006 New Revision: 2870 URL: http://svn.semichrome.net?rev=2870&view=rev Log: Slightly improve hash table for Messages file. Paves way for more generic use of it, as well as more constant performance. Modified: trunk/netsurf/utils/messages.c Modified: trunk/netsurf/utils/messages.c URL: http://svn.semichrome.net/trunk/netsurf/utils/messages.c?rev=2870&r1=... ============================================================================== --- trunk/netsurf/utils/messages.c (original) +++ trunk/netsurf/utils/messages.c Sun Aug 20 00:37:58 2006 @@ -21,7 +21,7 @@ #include "netsurf/utils/utils.h" /** We store the messages in a fixed-size hash table. */ -#define HASH_SIZE 77 +#define HASH_SIZE 101 /** Maximum length of a key. */ #define MAX_KEY_LENGTH 24 @@ -126,13 +126,22 @@ * Hash function for keys. */ +/* This is Fowler Noll Vo - a very fast and simple hash ideal for short + * strings. See http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash for more + * details. + */ unsigned int messages_hash(const char *s) { - unsigned int i, z = 0; - if (!s) + unsigned int z = 0x01000193, i; + + if (s == NULL) return 0; - for (i = 0; i != MAX_KEY_LENGTH && s[i]; i++) - z += s[i] & 0x1f; /* lower 5 bits, case insensitive */ + + for (i = 0; i != MAX_KEY_LENGTH && s[i]; i++) { + z *= 0x01000193; + z ^= (s[i] & 0x1f); /* lower 5 bits, case insensitive */ + } + return z % HASH_SIZE; }