diff options
Diffstat (limited to 'APACHE_1_3_42/src/lib/sdbm/sdbm_hash.c')
-rw-r--r-- | APACHE_1_3_42/src/lib/sdbm/sdbm_hash.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/APACHE_1_3_42/src/lib/sdbm/sdbm_hash.c b/APACHE_1_3_42/src/lib/sdbm/sdbm_hash.c new file mode 100644 index 0000000000..4b04add367 --- /dev/null +++ b/APACHE_1_3_42/src/lib/sdbm/sdbm_hash.c @@ -0,0 +1,48 @@ +/* + * sdbm - ndbm work-alike hashed database library + * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). + * author: oz@nexus.yorku.ca + * status: public domain. keep it that way. + * + * hashing routine + */ + +#include "sdbm.h" +/* + * polynomial conversion ignoring overflows + * [this seems to work remarkably well, in fact better + * then the ndbm hash function. Replace at your own risk] + * use: 65599 nice. + * 65587 even better. + */ +long +sdbm_hash(str, len) +register char *str; +register int len; +{ + register unsigned long n = 0; + +#define DUFF /* go ahead and use the loop-unrolled version */ +#ifdef DUFF + +#define HASHC n = *str++ + 65599 * n + + if (len > 0) { + register int loop = (len + 8 - 1) >> 3; + + switch(len & (8 - 1)) { + case 0: do { + HASHC; case 7: HASHC; + case 6: HASHC; case 5: HASHC; + case 4: HASHC; case 3: HASHC; + case 2: HASHC; case 1: HASHC; + } while (--loop); + } + + } +#else + while (len--) + n = *str++ + 65599 * n; +#endif + return n; +} |