forked from acouzens/open5gs
425 lines
11 KiB
C
425 lines
11 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* Copyright (C) 2019-2020 by Sukchan Lee <acetcom@gmail.com>
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*
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* This file is part of Open5GS.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "ogs-core.h"
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typedef struct ogs_hash_entry_t ogs_hash_entry_t;
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struct ogs_hash_entry_t {
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ogs_hash_entry_t *next;
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unsigned int hash;
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const void *key;
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int klen;
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const void *val;
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};
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struct ogs_hash_index_t {
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ogs_hash_t *ht;
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ogs_hash_entry_t *this, *next;
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unsigned int index;
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};
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struct ogs_hash_t {
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ogs_hash_entry_t **array;
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ogs_hash_index_t iterator; /* For ogs_hash_first(NULL, ...) */
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unsigned int count, max, seed;
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ogs_hashfunc_t hash_func;
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ogs_hash_entry_t *free; /* List of recycled entries */
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};
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#define INITIAL_MAX 15 /* tunable == 2^n - 1 */
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static ogs_hash_entry_t **alloc_array(ogs_hash_t *ht, unsigned int max)
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{
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ogs_hash_entry_t **ptr = ogs_calloc(1, sizeof(*ht->array) * (max + 1));
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ogs_assert(ptr);
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return ptr;
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}
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ogs_hash_t *ogs_hash_make(void)
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{
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ogs_hash_t *ht;
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ogs_time_t now = ogs_get_monotonic_time();
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ht = ogs_malloc(sizeof(ogs_hash_t));
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if (!ht) {
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ogs_error("ogs_malloc() failed");
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return NULL;
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}
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ht->free = NULL;
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ht->count = 0;
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ht->max = INITIAL_MAX;
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ht->seed = (unsigned int)((now >> 32) ^ now ^
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(uintptr_t)ht ^ (uintptr_t)&now) - 1;
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ht->array = alloc_array(ht, ht->max);
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ht->hash_func = NULL;
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return ht;
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}
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ogs_hash_t *ogs_hash_make_custom(ogs_hashfunc_t hash_func)
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{
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ogs_hash_t *ht = ogs_hash_make();
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if (!ht) {
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ogs_error("ogs_hash_make() failed");
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return NULL;
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}
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ht->hash_func = hash_func;
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return ht;
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}
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void ogs_hash_destroy(ogs_hash_t *ht)
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{
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ogs_hash_entry_t *he = NULL, *next_he = NULL;
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ogs_assert(ht);
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ogs_assert(ht->array);
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ogs_hash_clear(ht);
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he = ht->free;
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while(he) {
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next_he = he->next;
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ogs_free(he);
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he = next_he;
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}
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ogs_free(ht->array);
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ogs_free(ht);
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}
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ogs_hash_index_t *ogs_hash_next(ogs_hash_index_t *hi)
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{
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ogs_assert(hi);
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hi->this = hi->next;
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while (!hi->this) {
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if (hi->index > hi->ht->max)
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return NULL;
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hi->this = hi->ht->array[hi->index++];
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}
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hi->next = hi->this->next;
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return hi;
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}
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ogs_hash_index_t *ogs_hash_first(ogs_hash_t *ht)
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{
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ogs_hash_index_t *hi;
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ogs_assert(ht);
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hi = &ht->iterator;
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hi->ht = ht;
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hi->index = 0;
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hi->this = NULL;
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hi->next = NULL;
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return ogs_hash_next(hi);
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}
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void ogs_hash_this(ogs_hash_index_t *hi,
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const void **key, int *klen, void **val)
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{
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ogs_assert(hi);
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if (key) *key = hi->this->key;
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if (klen) *klen = hi->this->klen;
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if (val) *val = (void *)hi->this->val;
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}
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const void *ogs_hash_this_key(ogs_hash_index_t *hi)
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{
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const void *key;
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ogs_hash_this(hi, &key, NULL, NULL);
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return key;
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}
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int ogs_hash_this_key_len(ogs_hash_index_t *hi)
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{
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int klen;
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ogs_hash_this(hi, NULL, &klen, NULL);
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return klen;
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}
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void *ogs_hash_this_val(ogs_hash_index_t *hi)
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{
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void *val;
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ogs_hash_this(hi, NULL, NULL, &val);
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return val;
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}
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static void expand_array(ogs_hash_t *ht)
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{
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ogs_hash_index_t *hi;
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ogs_hash_entry_t **new_array;
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unsigned int new_max;
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new_max = ht->max * 2 + 1;
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new_array = alloc_array(ht, new_max);
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for (hi = ogs_hash_first(ht); hi; hi = ogs_hash_next(hi)) {
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unsigned int i = hi->this->hash & new_max;
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hi->this->next = new_array[i];
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new_array[i] = hi->this;
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}
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ogs_free(ht->array);
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ht->array = new_array;
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ht->max = new_max;
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}
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static unsigned int hashfunc_default(
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const char *char_key, int *klen, unsigned int hash)
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{
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const unsigned char *key = (const unsigned char *)char_key;
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const unsigned char *p;
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int i;
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/*
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* This is the popular `times 33' hash algorithm which is used by
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* perl and also appears in Berkeley DB. This is one of the best
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* known hash functions for strings because it is both computed
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* very fast and distributes very well.
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*
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* The originator may be Dan Bernstein but the code in Berkeley DB
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* cites Chris Torek as the source. The best citation I have found
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* is "Chris Torek, Hash function for text in C, Usenet message
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* <27038@mimsy.umd.edu> in comp.lang.c , October, 1990." in Rich
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* Salz's USENIX 1992 paper about INN which can be found at
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* <http://citeseer.nj.nec.com/salz92internetnews.html>.
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*
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* The magic of number 33, i.e. why it works better than many other
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* constants, prime or not, has never been adequately explained by
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* anyone. So I try an explanation: if one experimentally tests all
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* multipliers between 1 and 256 (as I did while writing a low-level
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* data structure library some time ago) one detects that even
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* numbers are not useable at all. The remaining 128 odd numbers
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* (except for the number 1) work more or less all equally well.
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* They all distribute in an acceptable way and this way fill a hash
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* table with an average percent of approx. 86%.
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*
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* If one compares the chi^2 values of the variants (see
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* Bob Jenkins ``Hashing Frequently Asked Questions'' at
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* http://burtleburtle.net/bob/hash/hashfaq.html for a description
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* of chi^2), the number 33 not even has the best value. But the
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* number 33 and a few other equally good numbers like 17, 31, 63,
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* 127 and 129 have nevertheless a great advantage to the remaining
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* numbers in the large set of possible multipliers: their multiply
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* operation can be replaced by a faster operation based on just one
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* shift plus either a single addition or subtraction operation. And
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* because a hash function has to both distribute good _and_ has to
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* be very fast to compute, those few numbers should be preferred.
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*
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* -- Ralf S. Engelschall <rse@engelschall.com>
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*/
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if (*klen == OGS_HASH_KEY_STRING) {
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for (p = key; *p; p++) {
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hash = hash * 33 + *p;
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}
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*klen = p - key;
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}
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else {
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for (p = key, i = *klen; i; i--, p++) {
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hash = hash * 33 + *p;
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}
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}
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return hash;
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}
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unsigned int ogs_hashfunc_default(const char *char_key, int *klen)
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{
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return hashfunc_default(char_key, klen, 0);
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}
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static ogs_hash_entry_t **find_entry(ogs_hash_t *ht,
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const void *key, int klen, const void *val, const char *file_line)
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{
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ogs_hash_entry_t **hep, *he;
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unsigned int hash;
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if (ht->hash_func)
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hash = ht->hash_func(key, &klen);
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else
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hash = hashfunc_default(key, &klen, ht->seed);
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/* scan linked list */
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for (hep = &ht->array[hash & ht->max], he = *hep;
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he; hep = &he->next, he = *hep) {
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if (he->hash == hash
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&& he->klen == klen
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&& memcmp(he->key, key, klen) == 0)
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break;
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}
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if (he || !val)
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return hep;
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/* add a new entry for non-NULL values */
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if ((he = ht->free) != NULL)
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ht->free = he->next;
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else {
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he = ogs_malloc(sizeof(*he));
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ogs_assert(he);
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}
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he->next = NULL;
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he->hash = hash;
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he->key = key;
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he->klen = klen;
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he->val = val;
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*hep = he;
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ht->count++;
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return hep;
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}
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void *ogs_hash_get_debug(ogs_hash_t *ht,
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const void *key, int klen, const char *file_line)
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{
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ogs_hash_entry_t *he;
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ogs_assert(ht);
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ogs_assert(key);
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ogs_assert(klen);
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he = *find_entry(ht, key, klen, NULL, file_line);
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if (he)
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return (void *)he->val;
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else
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return NULL;
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}
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void ogs_hash_set_debug(ogs_hash_t *ht,
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const void *key, int klen, const void *val, const char *file_line)
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{
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ogs_hash_entry_t **hep;
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ogs_assert(ht);
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ogs_assert(key);
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ogs_assert(klen);
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hep = find_entry(ht, key, klen, val, file_line);
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if (*hep) {
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if (!val) {
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/* delete entry */
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ogs_hash_entry_t *old = *hep;
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*hep = (*hep)->next;
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old->next = ht->free;
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ht->free = old;
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--ht->count;
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} else {
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/* replace entry */
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(*hep)->val = val;
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/* check that the collision rate isn't too high */
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if (ht->count > ht->max) {
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expand_array(ht);
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}
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}
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}
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/* else key not present and val==NULL */
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}
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void *ogs_hash_get_or_set_debug(ogs_hash_t *ht,
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const void *key, int klen, const void *val, const char *file_line)
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{
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ogs_hash_entry_t **hep;
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ogs_assert(ht);
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ogs_assert(key);
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ogs_assert(klen);
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hep = find_entry(ht, key, klen, val, file_line);
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if (*hep) {
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val = (*hep)->val;
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/* check that the collision rate isn't too high */
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if (ht->count > ht->max) {
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expand_array(ht);
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}
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return (void *)val;
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}
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/* else key not present and val==NULL */
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return NULL;
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}
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unsigned int ogs_hash_count(ogs_hash_t *ht)
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{
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ogs_assert(ht);
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return ht->count;
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}
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void ogs_hash_clear(ogs_hash_t *ht)
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{
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ogs_hash_index_t *hi;
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ogs_assert(ht);
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for (hi = ogs_hash_first(ht); hi; hi = ogs_hash_next(hi))
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ogs_hash_set(ht, hi->this->key, hi->this->klen, NULL);
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}
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/* This is basically the following...
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* for every element in hash table {
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* comp elemeny.key, element.value
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* }
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*
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* Like with table_do, the comp callback is called for each and every
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* element of the hash table.
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*/
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int ogs_hash_do(ogs_hash_do_callback_fn_t *comp,
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void *rec, const ogs_hash_t *ht)
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{
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ogs_hash_index_t hix;
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ogs_hash_index_t *hi;
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int rv, dorv = 1;
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hix.ht = (ogs_hash_t *)ht;
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hix.index = 0;
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hix.this = NULL;
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hix.next = NULL;
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if ((hi = ogs_hash_next(&hix))) {
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/* Scan the entire table */
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do {
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rv = (*comp)(rec, hi->this->key, hi->this->klen, hi->this->val);
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} while (rv && (hi = ogs_hash_next(hi)));
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if (rv == 0) {
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dorv = 0;
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}
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}
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return dorv;
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}
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