8363673be6
Added tracking of the number of inserted elements to the hashtable. Also added utility function to get the size of the hashtable.
136 lines
4.7 KiB
C
136 lines
4.7 KiB
C
#ifndef _HASTABLE_H
|
|
#define _HASTABLE_H
|
|
/*
|
|
* This file is distributed as part of the MariaDB Corporation MaxScale. It 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,
|
|
* version 2.
|
|
*
|
|
* 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., 51
|
|
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Copyright MariaDB Corporation Ab 2013-2014
|
|
*/
|
|
|
|
/**
|
|
* @file hashtable.h A general purpose hashtable mechanism for use within the
|
|
* gateway
|
|
*
|
|
* @verbatim
|
|
* Revision History
|
|
*
|
|
* Date Who Description
|
|
* 23/06/2013 Mark Riddoch Initial implementation
|
|
* 23/07/2013 Mark Riddoch Addition of iterator mechanism
|
|
* 08/01/2014 Massimiliano Pinto Added function pointers for key/value copy and free
|
|
* the routine hashtable_memory_fns() changed accordingly
|
|
*
|
|
* @endverbatim
|
|
*/
|
|
#include <skygw_debug.h>
|
|
#include <spinlock.h>
|
|
#include <atomic.h>
|
|
#include <dcb.h>
|
|
|
|
/**
|
|
* The entries within a hashtable.
|
|
*
|
|
* A NULL value for key indicates an empty entry.
|
|
* The next pointer is the overflow chain for this hashentry.
|
|
*/
|
|
typedef struct hashentry {
|
|
void *key; /**< The value of the key or NULL if empty entry */
|
|
void *value; /**< The value associated with key */
|
|
struct hashentry *next; /**< The overflow chain */
|
|
} HASHENTRIES;
|
|
|
|
/**
|
|
* HASHTABLE iterator - used to walk the hashtable in a thread safe
|
|
* way
|
|
*/
|
|
typedef struct hashiterator {
|
|
struct hashtable
|
|
*table; /**< The hashtable the iterator refers to */
|
|
int chain; /**< The current chain we are walking */
|
|
int depth; /**< The current depth down the chain */
|
|
} HASHITERATOR;
|
|
|
|
/**
|
|
* The type definition for the memory allocation functions
|
|
*/
|
|
typedef void *(*HASHMEMORYFN)(void *);
|
|
|
|
/**
|
|
* The general purpose hashtable struct.
|
|
*/
|
|
typedef struct hashtable {
|
|
#if defined(SS_DEBUG)
|
|
skygw_chk_t ht_chk_top;
|
|
#endif
|
|
int hashsize; /**< The number of HASHENTRIES */
|
|
HASHENTRIES **entries; /**< The entries themselves */
|
|
int (*hashfn)(void *); /**< The hash function */
|
|
int (*cmpfn)(void *, void *); /**< The key comparison function */
|
|
HASHMEMORYFN kcopyfn; /**< Optional key copy function */
|
|
HASHMEMORYFN vcopyfn; /**< Optional value copy function */
|
|
HASHMEMORYFN kfreefn; /**< Optional key free function */
|
|
HASHMEMORYFN vfreefn; /**< Optional value free function */
|
|
SPINLOCK spin; /**< Internal spinlock for the hashtable */
|
|
int n_readers; /**< Number of clients reading the table */
|
|
int writelock; /**< The table is locked by a writer */
|
|
bool ht_isflat; /**< Indicates whether hashtable is in stack or heap */
|
|
int n_elements; /*< Number of added elements */
|
|
#if defined(SS_DEBUG)
|
|
skygw_chk_t ht_chk_tail;
|
|
#endif
|
|
} HASHTABLE;
|
|
|
|
extern HASHTABLE *hashtable_alloc(int, int (*hashfn)(), int (*cmpfn)());
|
|
HASHTABLE *hashtable_alloc_flat(HASHTABLE* target,
|
|
int size,
|
|
int (*hashfn)(),
|
|
int (*cmpfn)());
|
|
/**< Allocate a hashtable */
|
|
extern void hashtable_memory_fns(HASHTABLE *table,
|
|
HASHMEMORYFN kcopyfn,
|
|
HASHMEMORYFN vcopyfn,
|
|
HASHMEMORYFN kfreefn,
|
|
HASHMEMORYFN vfreefn);
|
|
/**< Provide an interface to control key/value memory
|
|
* manipulation
|
|
*/
|
|
extern void hashtable_free(HASHTABLE *); /**< Free a hashtable */
|
|
extern int hashtable_add(HASHTABLE *, void *, void *); /**< Add an entry */
|
|
extern int hashtable_delete(HASHTABLE *, void *);
|
|
/**< Delete an entry table */
|
|
extern void *hashtable_fetch(HASHTABLE *, void *);
|
|
/**< Fetch the data for a given key */
|
|
extern void hashtable_stats(HASHTABLE *); /**< Print statisitics */
|
|
void hashtable_get_stats(
|
|
void* hashtable,
|
|
int* hashsize,
|
|
int* nelems,
|
|
int* longest);
|
|
extern int hashtable_save(HASHTABLE *,
|
|
char *,
|
|
int (*keywrite)(int, void*),
|
|
int (*valuewrite)(int, void*));
|
|
extern int hashtable_load(HASHTABLE *,
|
|
char *,
|
|
void *(*keyread)(int),
|
|
void *(*valueread)(int));
|
|
|
|
extern HASHITERATOR *hashtable_iterator(HASHTABLE *);
|
|
/**< Allocate an iterator on the hashtable */
|
|
extern void *hashtable_next(HASHITERATOR *);
|
|
/**< Return the key of the hash table iterator */
|
|
extern void hashtable_iterator_free(HASHITERATOR *);
|
|
extern int hashtable_size(HASHTABLE *table);
|
|
#endif
|