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A Neat HashTable Implementation
/*
* Copyright (c) 2011 Eddie Ringle <eddie@eringle.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "hashtable.h"
HashTable *crb_hashtable_create(uint32_t _size) {
HashTable *tbl = malloc(sizeof(HashTable));
tbl->size = 0;
tbl->capacity = 0;
tbl->table = NULL;
return tbl;
}
void crb_hashtable_destroy(HashTable **_tbl) {
if (_tbl == NULL || *_tbl == NULL) return;
if ((*_tbl)->table != NULL) {
free((*_tbl)->table);
(*_tbl)->table = NULL;
}
free(*_tbl);
*_tbl = NULL;
}
void crb_hashtable_grow(HashTable *_tbl) {
unsigned int oldCapacity;
struct table_entry **oldTable;
unsigned int i;
if (_tbl == NULL) return;
oldCapacity = _tbl->capacity;
if (_tbl->capacity > 0) {
_tbl->capacity *= 2;
} else {
_tbl->capacity = 32;
}
oldTable = _tbl->table;
_tbl->table = calloc(_tbl->capacity, sizeof(struct table_entry*));
for (i = 0; i < oldCapacity; i++) {
if (oldTable[i] != NULL) {
crb_hashtable_insert(_tbl, oldTable[i]->key, oldTable[i]->value);
free(oldTable[i]);
}
}
free(oldTable);
}
void crb_hashtable_hash(const char *_key, uint32_t *hash) {
murmurhash3_x86_32(_key, strlen(_key), 0, hash);
}
bool crb_hashtable_insert(HashTable *_tbl, const char *_key, void *_data) {
struct table_entry *entry, *next_entry;
uint32_t index;
if (_tbl == NULL || _key == NULL || _data == NULL) return false;
if (_tbl->size == _tbl->capacity) {
crb_hashtable_grow(_tbl);
}
entry = malloc(sizeof(struct table_entry));
if (entry == NULL) return false;
crb_hashtable_hash(_key, &entry->hash);
index = entry->hash % _tbl->capacity;
entry->key = crb_strdup(_key);
entry->value = _data;
entry->next = NULL;
if (_tbl->table[index] == NULL) {
_tbl->table[index] = entry;
} else {
next_entry = _tbl->table[index];
while (next_entry != NULL) {
if (next_entry->next == NULL) {
next_entry->next = entry;
break;
}
next_entry = next_entry->next;
}
}
_tbl->size++;
return true;
}
void *crb_hashtable_find(HashTable *_tbl, const char *_key) {
uint32_t hash;
struct table_entry *entry;
if (_tbl == NULL || _key == NULL) return NULL;
crb_hashtable_hash(_key, &hash);
for (entry = _tbl->table[hash % _tbl->capacity]; entry != NULL; entry = entry->next) {
if (strcmp(_key, entry->key) == 0) return entry->value;
}
return NULL;
}
void *crb_hashtable_remove(HashTable *_tbl, const char *_key) {
uint32_t hash;
struct table_entry *entry, *sibling;
bool top = true;
void *data;
if (_tbl == NULL || _key == NULL) return NULL;
crb_hashtable_hash(_key, &hash);
for (entry = _tbl->table[hash % _tbl->capacity]; entry != NULL; sibling = entry, entry = entry->next) {
if (strcmp(_key, entry->key) == 0) {
break;
} else {
top = false;
}
}
if (entry != NULL) {
data = entry->value;
if (top) {
if (entry->next != NULL) {
_tbl->table[hash % _tbl->capacity] = entry->next;
} else {
_tbl->table[hash % _tbl->capacity] = NULL;
}
} else {
if (entry->next != NULL) {
sibling->next = entry->next;
} else {
sibling->next = NULL;
}
}
free(entry->key);
free(entry);
entry = NULL;
_tbl->size--;
return data;
}
return NULL;
}
/*
* Copyright (c) 2011 Eddie Ringle <eddie@eringle.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __included_hashtable_h
#define __included_hashtable_h
#include "universal_include.h"
#include "murmurhash.h"
struct table_entry {
char *key;
void *value;
uint32_t hash;
struct table_entry *next;
};
struct hash_table {
uint32_t capacity;
uint32_t size;
struct table_entry **table;
};
typedef struct hash_table HashTable;
HashTable *crb_hashtable_create(uint32_t _size);
void crb_hashtable_destroy(HashTable **_tbl);
void crb_hashtable_grow(HashTable *_tbl);
void crb_hashtable_hash(const char *_key, uint32_t *hash);
bool crb_hashtable_insert(HashTable *_tbl, const char *_key, void *_data);
void *crb_hashtable_find(HashTable *_tbl, const char *_key);
void *crb_hashtable_remove(HashTable *_tbl, const char *_key);
#endif /* __included_hashtable_h */
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