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/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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;
}
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