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ohtbl.c
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ohtbl.c
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/*
* Copyright (c) 2014, Jusse Wang <wanyco@gmail.com>.
* All rights reserved.
*
* @date: 2014-11-07
* @file ohtbl.c
* @brief open-addressed hash tables implementation file
*
*/
/* ohtbl.c - open-addressed hash tables */
/* */
/* This program is free software; you can redistribute it and/or modify */
/* it under the terms of the GNU General Public License as published by */
/* the Free Software Foundation; either version 2, or (at your option) */
/* any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program; if not, write to the Free Software */
/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA */
/* 02111-1307, USA. */
/* code is based on "Mastering Algorithms with C", Kyle Loudon */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <sys/types.h>
#include <linux/types.h>
#include <assert.h>
#include "ohtbl.h"
#define l7_log_err printf
/**
* Reserve a memory location
* when a element be removed, the hash table element's data pointer will be set to the vacated's address
*/
static char vacated;
/**
* @function: obthl_init
* @bried: open-addressed hash table initialization
* @param: htbl: the open-addressed hash table pointer, you must allocate it well before.
* size: the hash table size
* h1: calculate hash value function pointer 1
* h2: calculate hash value function pointer 2
* match:match hash table element function pointer
* alloc: allocate hash table memory function pointer
* destroy: free/destroy hash table memory function pointer
* tolerance: the maximum number of hash table element tolerance
* @return: 1 if everything ok, otherwise return 0.
*/
uint16_t g_proc_index = 0;
int ohtbl_init(ohtbl_t *htbl, unsigned int size, unsigned int (*h1)(const void *elem),
unsigned int (*h2)(const void *elem), int (*match)(const void *ohtbl_elem, const void *elem),
void *(*alloc)(size_t), void (*destroy)(void *data), unsigned int tolerance)
{
unsigned int i;
unsigned int hash_size_byte, active_size_byte;
rwlock_init(&htbl->lock);
hash_size_byte = (size + 1) * sizeof(struct ohtbl_item);
htbl->table = (struct ohtbl_item *)alloc(hash_size_byte);
if (htbl->table == NULL) {
return 0;
}
memset(htbl->table, 0, hash_size_byte);
active_size_byte = (size + 1) * sizeof(unsigned int);
htbl->active = (unsigned int *)alloc(active_size_byte);
if (htbl->active == NULL) {
destroy(htbl->table);
htbl->table = NULL;
return 0;
}
memset(htbl->active, 0, active_size_byte);
/* Initialize each position */
htbl->size = size;
for (i = 0; i < htbl->size; i++) {
htbl->table[i].data = NULL;
}
/* Set the vacated member to the sentinel memory address reserved for this */
htbl->vacated = &vacated;
/* Encapsulate the functions */
htbl->h1 = h1;
htbl->h2 = h2;
htbl->match = match;
htbl->destroy = destroy;
/* Initialize the number of elements in the table */
htbl->count = htbl->conflict = 0;
/* Initialize tolerance */
htbl->tolerance = tolerance >= size ? (size * 0.8) : tolerance;
return 1;
}
/**
* @function: ohtbl_reset
* @brief: reset all the hash table element to zero, you have to manage the element pointer (e.g. reuse/free)
* @param: htbl: the open-addressed hash table which to reset.
* @return: void
*/
void ohtbl_reset(ohtbl_t *htbl)
{
int lock_ret;
unsigned int hash_size_byte, active_size_byte;
if (htbl == NULL) {
return;
}
lock_ret = rwlock_wrlock_ms(&htbl->lock, 5000);
if (lock_ret == 0) {
l7_log_err("hash table wrlock() error, write: %d --- flag: %"PRIu64", read: %d --- flag: %"PRIu64"", htbl->lock.write, htbl->lock.wrflag, htbl->lock.read, htbl->lock.rdflag);
}
hash_size_byte = (htbl->size + 1) * sizeof(struct ohtbl_item);
memset(htbl->table, 0, hash_size_byte);
active_size_byte = (htbl->size + 1) * sizeof(uint32_t);
memset(htbl->active, 0, active_size_byte);
htbl->count = htbl->conflict = 0;
rwlock_init(&htbl->lock);
rwlock_wrunlock(&htbl->lock);
}
/**
* @function: ohtbl_destroy
* @brief: destroy the hash table
* @param: htbl: the open-addressed hash table which to destroy.
* @return: void
*/
void ohtbl_destroy(ohtbl_t *htbl)
{
unsigned int i;
if (htbl->destroy != NULL){
/* Call a user-defined function to free dynamically allocated data */
for (i = 0; i < htbl->size; i++) {
if (htbl->table[i].data != NULL && htbl->table[i].data != htbl->vacated) {
htbl->destroy(htbl->table[i].data);
}
}
}
/* Free the storage allocated for the actives table */
htbl->destroy(htbl->active);
/* Free the storage allocated for the hash table */
htbl->destroy(htbl->table);
//* No operations are allowed now, but clear the structure as a precaution */
memset(htbl, 0, sizeof(ohtbl_t));
}
/**
* @function: obthl_insert
* @brief: insert elem into hash table
* @param: htbl: the hash table which to insert
* elem: hash table element
* @return: 1 if there is no conflict, return -1 when the hash table element number
* reached the maximum tolerated value, otherwise return 0
*/
int ohtbl_insert(ohtbl_t *htbl, void *elem)
{
int lock_ret;
unsigned int key = 0;
/* Do not exceed the tolerance in the table */
if (htbl->count == htbl->tolerance) {
return -1;
}
/* Do nothing if the data is already in the table */
if (__ohtbl_lookup(htbl, elem, &key) != NULL) {
return 0;
}
/* Insert the data into the table */
htbl->table[key].data = elem;
htbl->table[key].hash = key;
/* Record pos in active[] */
lock_ret = rwlock_wrlock_ms(&htbl->lock, 1000);
if (lock_ret == 0) {
l7_log_err("hash table wrlock() error, write:%d --- flag: %"PRIu64", read:%d --- flag: %"PRIu64"",
htbl->lock.write, htbl->lock.wrflag, htbl->lock.read, htbl->lock.rdflag);
}
htbl->active[htbl->count] = key;
htbl->count++;
htbl->table[key].pos = htbl->count;
if (lock_ret != 0) {
rwlock_wrunlock(&htbl->lock);
}
if (key != htbl->h1(elem) % htbl->size) {
htbl->conflict++;
}
return 1;
}
/**
* @function: obtbl_remove
* @brief: remove the elem from hash table
* @param: htbl: the hash table
* elem: the element which to remove
* @return: the element pointer which be removed, or NULL
*/
void *ohtbl_remove(ohtbl_t *htbl, const void *elem)
{
int lock_ret;
unsigned int pos = 0;
unsigned int tmp_key = 0;
unsigned int i = 0;
unsigned int key = 0;
unsigned int next_key = 0;
unsigned int is_conflict = 0;
void *ret = NULL;
if (htbl == NULL || htbl->count == 0) {
return NULL;
}
for (i = 0; i < htbl->size; i++){
key = (htbl->h1(elem) + i * htbl->h2(elem)) % htbl->size;
if (htbl->table[key].data == NULL) {
/* Return that the elem was not found */
return NULL;
} else if (htbl->table[key].data == htbl->vacated) {
/* Search beyond vacated positions */
continue;
} else if (htbl->match(htbl->table[key].data, elem)) {
/* Pass back the elem from the table */
ret = htbl->table[key].data;
htbl->table[key].data = htbl->vacated;
/* Remove pos in active[] */
lock_ret = rwlock_wrlock_ms(&htbl->lock, 1000);
if (lock_ret == 0) {
l7_log_err("hash table wrlock() error, write:%d --- flag: %"PRIu64", read:%d --- flag: %"PRIu64"",
htbl->lock.write, htbl->lock.wrflag, htbl->lock.read, htbl->lock.rdflag);
}
htbl->count--;
pos = htbl->table[key].pos;
if (pos <= htbl->count) {
tmp_key = htbl->active[htbl->count];
htbl->active[pos - 1] = tmp_key;
htbl->table[tmp_key].pos = pos;
}
if (lock_ret != 0) {
rwlock_wrunlock(&htbl->lock);
}
if ((i + 1) < htbl->size) {
next_key = (htbl->h1(elem) + (i + 1) * htbl->h2(elem)) % htbl->size;
if (htbl->table[next_key].data != NULL) {
is_conflict = 1;
}
}
if (is_conflict == 1 && htbl->conflict > 0) {
htbl->conflict--;
}
return ret;
}
is_conflict = 1;
}
return ret;
}
#if 0
/**
* @function: ohtbl_flush
* @brief: flush current position for traversing
* @param: htbl: the hash table
* @return: void
*/
void ohtbl_flush(ohtbl_t *htbl)
{
htbl->cur = htbl->head;
}
/**
* @function: ohtbl_traverse
* @brief: Traverse hash table
* @param: htbl: the hash table
* @return: the hash table element pointer, or NULL
*/
void *ohtbl_traverse(ohtbl_t *htbl)
{
if (htbl->cur == htbl->tail) {
return NULL;
}
htbl->cur = htbl->cur->next;
return htbl->cur->data;
}
#endif
/**
* @function: ohtbl_foreach
* @brief: traverse the hash table, and calls the callback function on each element
* @param: htbl: the hash table
* callback: the callback function pointer
* data: the argument of callback function
* @return: void
*/
void ohtbl_foreach(ohtbl_t *htbl, void (*callback)(void *ohtbl_elem, void *data), void *data)
{
int lock_ret;
unsigned int pos, key;
void *elem;
if (htbl == NULL || callback == NULL) {
return;
}
lock_ret = rwlock_rdlock_ms(&htbl->lock, 2000);
if (lock_ret == 0) {
l7_log_err("hash table rdlock() error, write:%d --- flag: %"PRIu64", read:%d --- flag: %"PRIu64"",
htbl->lock.write, htbl->lock.wrflag, htbl->lock.read, htbl->lock.rdflag);
}
for(pos = 0; pos < htbl->count; pos++) {
key = htbl->active[pos];
elem = htbl->table[key].data;
callback(elem, data);
}
if (lock_ret != 0) {
rwlock_rdunlock(&htbl->lock);
}
}
/**
* @function: __ohtbl_lookup
* @brief: lookup the elem whether in the hash table
* @param: htbl: the hash table
* elem: the element which will to be lookup
* ekey: use to save the elem's hash table key
* @return: the hash table element pointer, or NULL
*/
void *__ohtbl_lookup(ohtbl_t *htbl, const void *elem, unsigned int *ekey)
{
unsigned int key = 0;
unsigned int i = 0, n = 0;
/* Use double hashing to hash the key */
for (i = 0; i < htbl->size; i++) {
key = (htbl->h1(elem) + i * htbl->h2(elem)) % htbl->size;
if (htbl->table[key].data == NULL) {
/* Return that the elem was not found */
if (ekey != NULL && n == 0) {
*ekey = key;
n++;
}
return NULL;
} else if (htbl->table[key].data == htbl->vacated) {
if (ekey != NULL && n == 0) {
*ekey = key;
n++;
}
continue;
} else if (htbl->match(htbl->table[key].data, elem)) {
if (ekey != NULL) {
*ekey = key;
}
/* Data was found */
return htbl->table[key].data;
}
}
/* Return that the elem was not found */
return NULL;
}