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| author | Nathan Moinvaziri <nathan@nathanm.com> | 2020-04-30 21:05:05 -0700 |
|---|---|---|
| committer | Hans Kristian Rosbach <hk-github@circlestorm.org> | 2020-05-24 14:32:26 +0200 |
| commit | 07207681ed29d6cc7528df9d5cf8f587c6199a1c (patch) | |
| tree | 85f008dc8b81a40258e346d20068246d53ce57a2 /insert_string.c | |
| parent | 600dcc301259f006af5e7141ae9b7129d24f23ef (diff) | |
Simplify generic hash function using knuth's multiplicative hash.
Diffstat (limited to 'insert_string.c')
| -rw-r--r-- | insert_string.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/insert_string.c b/insert_string.c index e9efd51..774d18a 100644 --- a/insert_string.c +++ b/insert_string.c @@ -15,16 +15,8 @@ * previous key instead of complete recalculation each time. */ -#if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86) -# define UPDATE_HASH(s, h, val) \ - h = (3483 * ((val) & 0xff) +\ - 23081 * (((val) >> 8) & 0xff) +\ - 6954 * (((val) >> 16) & 0xff) +\ - 20947 * (((val) >> 24) & 0xff)); -#else -# define UPDATE_HASH(s, h, val)\ - h = (s->ins_h = ((s->ins_h << s->hash_shift) ^ ((val) >> ((MIN_MATCH - 1) * 8))) & s->hash_mask) -#endif +#define UPDATE_HASH(s, h, val) \ + h = ((val * 2654435761U) >> (32 - s->hash_bits)); #define INSERT_STRING insert_string_c #define QUICK_INSERT_STRING quick_insert_string_c |