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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: clib/hash.h $ */
/* */
/* OpenPOWER FFS Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2014,2015 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* 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. */
/* */
/* IBM_PROLOG_END_TAG */
/*
* File: hash.h
* Author: Shaun Wetzstein <shaun@us.ibm.com>
* Descr: Various int32 hash functions
* Note:
* Date: 10/03/10
*/
#ifndef __HASH_H__
#define __HASH_H__
#include <stdint.h>
/* ======================================================================= */
static inline int32_t int32_hash1(int32_t);
static inline int32_t int32_hash2(int32_t);
static inline int32_t int32_hash3(int32_t);
typedef uint32_t(*hash_t) (char *, uint32_t);
static inline uint32_t rs_hash(char *, uint32_t);
static inline uint32_t js_hash(char *, uint32_t);
static inline uint32_t pjw_hash(char *, uint32_t);
static inline uint32_t elf_hash(char *, uint32_t);
static inline uint32_t bkdr_hash(char *, uint32_t);
static inline uint32_t sdbm_hash(char *, uint32_t);
static inline uint32_t djb_hash(char *, uint32_t);
static inline uint32_t dek_hash(char *, uint32_t);
static inline uint32_t bp_hash(char *, uint32_t);
static inline uint32_t fnv_hash(char *, uint32_t);
static inline uint32_t ap_hash(char *, uint32_t);
/* ======================================================================= */
static inline int32_t int32_hash1(int32_t key)
{
key = ~key + (key << 15);
key = key ^ (key >> 12);
key = key + (key << 2);
key = key ^ (key >> 4);
key = key * 2057;
key = key ^ (key >> 16);
return key;
}
static inline int32_t int32_hash2(int32_t key)
{
key = (key + 0x7ed55d16) + (key << 12);
key = (key ^ 0xc761c23c) ^ (key >> 19);
key = (key + 0x165667b1) + (key << 5);
key = (key + 0xd3a2646c) ^ (key << 9);
key = (key + 0xfd7046c5) + (key << 3);
key = (key ^ 0xb55a4f09) ^ (key >> 16);
return key;
}
static inline int32_t int32_hash3(int32_t key)
{
int32_t c2 = 0x27d4eb2d;
key = (key ^ 61) ^ (key >> 16);
key = key + (key << 3);
key = key ^ (key >> 4);
key = key * c2;
key = key ^ (key >> 15);
return key;
}
/* ======================================================================= */
static inline uint32_t rs_hash(char *str, uint32_t len)
{
uint32_t b = 378551;
uint32_t a = 63689;
uint32_t hash = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = hash * a + (*str);
a = a * b;
}
return hash;
}
static inline uint32_t js_hash(char *str, uint32_t len)
{
uint32_t hash = 1315423911;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash ^= ((hash << 5) + (*str) + (hash >> 2));
}
return hash;
}
static inline uint32_t pjw_hash(char *str, uint32_t len)
{
const uint32_t BitsInUnsignedInt = (uint32_t) (sizeof(uint32_t) * 8);
const uint32_t ThreeQuarters = (uint32_t) ((BitsInUnsignedInt * 3) / 4);
const uint32_t OneEighth = (uint32_t) (BitsInUnsignedInt / 8);
const uint32_t HighBits =
(uint32_t) (0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
uint32_t hash = 0;
uint32_t test = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = (hash << OneEighth) + (*str);
if ((test = hash & HighBits) != 0) {
hash = ((hash ^ (test >> ThreeQuarters)) & (~HighBits));
}
}
return hash;
}
static inline uint32_t elf_hash(char *str, uint32_t len)
{
uint32_t hash = 0;
uint32_t x = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = (hash << 4) + (*str);
if ((x = hash & 0xF0000000L) != 0) {
hash ^= (x >> 24);
}
hash &= ~x;
}
return hash;
}
static inline uint32_t bkdr_hash(char *str, uint32_t len)
{
uint32_t seed = 131; /* 31 131 1313 13131 131313 etc.. */
uint32_t hash = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = (hash * seed) + (*str);
}
return hash;
}
static inline uint32_t sdbm_hash(char *str, uint32_t len)
{
uint32_t hash = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = (*str) + (hash << 6) + (hash << 16) - hash;
}
return hash;
}
static inline uint32_t djb_hash(char *str, uint32_t len)
{
uint32_t hash = 5381;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = ((hash << 5) + hash) + (*str);
}
return hash;
}
static inline uint32_t dek_hash(char *str, uint32_t len)
{
uint32_t hash = len;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = ((hash << 5) ^ (hash >> 27)) ^ (*str);
}
return hash;
}
static inline uint32_t bp_hash(char *str, uint32_t len)
{
uint32_t hash = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash = hash << 7 ^ (*str);
}
return hash;
}
static inline uint32_t fnv_hash(char *str, uint32_t len)
{
const uint32_t fnv_prime = 0x811C9DC5;
uint32_t hash = 0;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash *= fnv_prime;
hash ^= (*str);
}
return hash;
}
static inline uint32_t ap_hash(char *str, uint32_t len)
{
uint32_t hash = 0xAAAAAAAA;
uint32_t i = 0;
for (i = 0; i < len; str++, i++) {
hash ^= ((i & 1) == 0) ? ((hash << 7) ^ (*str) * (hash >> 3)) :
(~((hash << 11) + ((*str) ^ (hash >> 5))));
}
return hash;
}
/* ======================================================================= */
#endif /* __HASH_H__ */
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