diff options
Diffstat (limited to 'rubbos/app/httpd-2.0.64/srclib/apr-util/dbm/sdbm/sdbm_hash.c')
-rw-r--r-- | rubbos/app/httpd-2.0.64/srclib/apr-util/dbm/sdbm/sdbm_hash.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/rubbos/app/httpd-2.0.64/srclib/apr-util/dbm/sdbm/sdbm_hash.c b/rubbos/app/httpd-2.0.64/srclib/apr-util/dbm/sdbm/sdbm_hash.c new file mode 100644 index 00000000..012e3d07 --- /dev/null +++ b/rubbos/app/httpd-2.0.64/srclib/apr-util/dbm/sdbm/sdbm_hash.c @@ -0,0 +1,63 @@ +/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as + * applicable. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* + * 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: ex-public domain. keep it that way. + * + * hashing routine + */ + +#include "apr_sdbm.h" +#include "sdbm_private.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(const char *str, 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; +} |