167 lines
4.7 KiB
C
167 lines
4.7 KiB
C
/*
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* Author: Christian Huitema
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* Copyright (c) 2017, Private Octopus, Inc.
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* All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL Private Octopus, Inc. BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Basic hash implementation, like we have seen tons off already.
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*/
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#include "picohash.h"
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#include <stdlib.h>
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#include <string.h>
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picohash_table* picohash_create(size_t nb_bin,
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uint64_t (*picohash_hash)(const void*),
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int (*picohash_compare)(const void*, const void*))
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{
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picohash_table* t = (picohash_table*)malloc(sizeof(picohash_table));
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if (t != NULL) {
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t->hash_bin = (picohash_item**)malloc(sizeof(picohash_item*) * nb_bin);
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if (t->hash_bin == NULL) {
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free(t);
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t = NULL;
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} else {
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(void)memset(t->hash_bin, 0, sizeof(picohash_item*) * nb_bin);
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t->nb_bin = nb_bin;
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t->count = 0;
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t->picohash_hash = picohash_hash;
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t->picohash_compare = picohash_compare;
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}
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}
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return t;
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}
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picohash_item* picohash_retrieve(picohash_table* hash_table, const void* key)
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{
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uint64_t hash = hash_table->picohash_hash(key);
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uint32_t bin = (uint32_t)(hash % hash_table->nb_bin);
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picohash_item* item = hash_table->hash_bin[bin];
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while (item != NULL) {
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if (hash_table->picohash_compare(key, item->key) == 0) {
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break;
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} else {
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item = item->next_in_bin;
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}
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}
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return item;
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}
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int picohash_insert(picohash_table* hash_table, const void* key)
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{
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uint64_t hash = hash_table->picohash_hash(key);
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uint32_t bin = (uint32_t)(hash % hash_table->nb_bin);
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int ret = 0;
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picohash_item* item = (picohash_item*)malloc(sizeof(picohash_item));
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if (item == NULL) {
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ret = -1;
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} else {
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item->hash = hash;
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item->key = key;
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item->next_in_bin = hash_table->hash_bin[bin];
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hash_table->hash_bin[bin] = item;
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hash_table->count++;
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}
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return ret;
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}
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void picohash_delete_item(picohash_table* hash_table, picohash_item* item, int delete_key_too)
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{
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uint32_t bin = (uint32_t)(item->hash % hash_table->nb_bin);
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picohash_item* previous = hash_table->hash_bin[bin];
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if (previous == item) {
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hash_table->hash_bin[bin] = item->next_in_bin;
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hash_table->count--;
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} else {
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while (previous != NULL) {
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if (previous->next_in_bin == item) {
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previous->next_in_bin = item->next_in_bin;
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hash_table->count--;
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break;
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} else {
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previous = previous->next_in_bin;
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}
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}
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}
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if (delete_key_too) {
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free((void*)item->key);
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}
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free(item);
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}
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void picohash_delete_key(picohash_table* hash_table, void* key, int delete_key_too)
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{
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picohash_item* item = picohash_retrieve(hash_table, key);
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if (item != NULL) {
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picohash_delete_item(hash_table, item, delete_key_too);
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}
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else if (delete_key_too) {
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free(key);
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}
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}
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void picohash_delete(picohash_table* hash_table, int delete_key_too)
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{
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for (uint32_t i = 0; i < hash_table->nb_bin; i++) {
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picohash_item* item = hash_table->hash_bin[i];
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while (item != NULL) {
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picohash_item* tmp = item;
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item = tmp->next_in_bin;
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if (delete_key_too) {
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free((void*)tmp->key);
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}
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free(tmp);
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}
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}
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free(hash_table->hash_bin);
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free(hash_table);
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}
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uint64_t picohash_hash_mix(uint64_t hash, uint64_t h2)
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{
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h2 ^= (hash << 17) ^ (hash >> 37);
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hash ^= ((h2 << 31) ^ (h2 >> 17));
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return hash;
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}
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uint64_t picohash_bytes(const uint8_t* key, uint32_t length)
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{
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uint64_t hash = 0xDEADBEEF;
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for (uint32_t i = 0; i < length; i++) {
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hash ^= key[i];
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hash ^= ((hash << 31) ^ (hash >> 17));
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}
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return hash;
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}
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