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/*
* Generic hash table implementation.
*
* Copyright (c) 2006 Dustin Sallings <dustin@spy.net>
*/
#ifndef GENHASH_H
#define GENHASH_H 1
#include <memcached/visibility.h>
#ifdef __cplusplus
extern "C" {
#endif
/*! \mainpage genhash
*
* \section intro_sec Introduction
*
* genhash is a generic hash table implementation in C. It's
* well-tested, freely available (MIT-license) and does what you need.
*
* \section docs_sec API Documentation
*
* Jump right into <a href="group___core.html">the API docs</a> to get started.
*/
/**
* \defgroup Core genhash core
*/
/**
* \addtogroup Core
* @{
*/
/**
* Operations on keys and values in the hash table.
*/
struct hash_ops {
/**
* Function to compute a hash for the given value.
*/
int (*hashfunc)(const void *, size_t);
/**
* Function that returns true if the given keys are equal.
*/
int (*hasheq)(const void *, size_t, const void *, size_t);
/**
* Function to duplicate a key for storage.
*/
void* (*dupKey)(const void *, size_t);
/**
* Function to duplicate a value for storage.
*/
void* (*dupValue)(const void *, size_t);
/**
* Function to free a key.
*/
void (*freeKey)(void *);
/**
* Function to free a value.
*/
void (*freeValue)(void *);
};
/**
* The hash table structure.
*/
typedef struct _genhash genhash_t ;
/**
* Type of update performed by an update function.
*/
enum update_type {
MODIFICATION, /**< This update is modifying an existing entry */
NEW /**< This update is creating a new entry */
};
/**
* Create a new generic hashtable.
*
* @param est the estimated number of items to store (must be > 0)
* @param ops the key and value operations
*
* @return the new genhash_t or NULL if one cannot be created
*/
MEMCACHED_PUBLIC_API
genhash_t* genhash_init(int est, struct hash_ops ops);
/**
* Free a gen hash.
*
* @param h the genhash to free (may be NULL)
*/
MEMCACHED_PUBLIC_API
void genhash_free(genhash_t *h);
/**
* Store an item.
*
* @param h the genhash
* @param k the key
* @param v the value
*/
MEMCACHED_PUBLIC_API
void genhash_store(genhash_t *h, const void *k, size_t klen,
const void *v, size_t vlen);
/**
* Get the most recent value stored for the given key.
*
* @param h the genhash
* @param k the key
*
* @return the value, or NULL if one cannot be found
*/
MEMCACHED_PUBLIC_API
void* genhash_find(genhash_t *h, const void *k, size_t klen);
/**
* Delete the most recent value stored for a key.
*
* @param h the genhash
* @param k the key
*
* @return the number of items deleted
*/
MEMCACHED_PUBLIC_API
int genhash_delete(genhash_t *h, const void *k, size_t klen);
/**
* Delete all mappings of a given key.
*
* @param h the genhash
* @param k the key
*
* @return the number of items deleted
*/
MEMCACHED_PUBLIC_API
int genhash_delete_all(genhash_t *h, const void *k, size_t klen);
/**
* Create or update an item in-place.
*
* @param h the genhash
* @param k the key
* @param v the new value to store for this key
*
* @return an indicator of whether this created a new item or updated
* an existing one
*/
MEMCACHED_PUBLIC_API
enum update_type genhash_update(genhash_t *h, const void *k, size_t klen,
const void *v, size_t vlen);
/**
* Create or update an item in-place with a function.
*
* @param h hashtable
* @param key the key of the item
* @param upd function that will be called with the key and current
* value. Should return the new value.
* @param fr function to free the return value returned by the update
* function
* @param def default value
*
* @return an indicator of whether this created a new item or updated
* an existing one
*/
MEMCACHED_PUBLIC_API
enum update_type genhash_fun_update(genhash_t *h, const void *key, size_t klen,
void *(*upd)(const void *k, const void *oldv,
size_t *ns, void *a),
void (*fr)(void*),
void *arg,
const void *def, size_t deflen);
/**
* Iterate all keys and values in a hash table.
*
* @param h the genhash
* @param iterfunc a function that will be called once for every k/v pair
* @param arg an argument to be passed to the iterfunc on each iteration
*/
MEMCACHED_PUBLIC_API
void genhash_iter(genhash_t *h,
void (*iterfunc)(const void* key, size_t nkey,
const void* val, size_t nval,
void *arg),
void *arg);
/**
* Iterate all values for a given key in a hash table.
*
* @param h the genhash
* @param key the key to iterate
* @param iterfunc a function that will be called once for every k/v pair
* @param arg an argument to be passed to the iterfunc on each iteration
*/
MEMCACHED_PUBLIC_API
void genhash_iter_key(genhash_t *h, const void* key, size_t nkey,
void (*iterfunc)(const void* key, size_t inkey,
const void* val, size_t inval,
void *arg),
void *arg);
/**
* Get the total number of entries in this hash table.
*
* @param h the genhash
*
* @return the number of entries in the hash table
*/
MEMCACHED_PUBLIC_API
int genhash_size(genhash_t *h);
/**
* Remove all items from a genhash.
*
* @param h the genhash
*
* @return the number of items removed
*/
MEMCACHED_PUBLIC_API
int genhash_clear(genhash_t *h);
/**
* Get the total number of entries in this hash table that map to the given
* key.
*
* @param h the genhash
* @param k a key
*
* @return the number of entries keyed with the given key
*/
MEMCACHED_PUBLIC_API
int genhash_size_for_key(genhash_t *h, const void *k, size_t nkey);
/**
* Convenient hash function for strings.
*
* @param k a null-terminated string key.
*
* @return a hash value for this string.
*/
MEMCACHED_PUBLIC_API
int genhash_string_hash(const void *k, size_t nkey);
/**
* @}
*/
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* GENHASH_H */
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