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/* Licensed under LGPLv2+ - see LICENSE file for details */
#ifndef CCAN_HTABLE_H
#define CCAN_HTABLE_H
#include "config.h"
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
/**
* struct htable - private definition of a htable.
*
* It's exposed here so you can put it in your structures and so we can
* supply inline functions.
*/
struct htable {
size_t (*rehash)(const void *elem, void *priv);
void *priv;
unsigned int bits;
size_t elems, deleted, max, max_with_deleted;
/* These are the bits which are the same in all pointers. */
uintptr_t common_mask, common_bits;
uintptr_t perfect_bit;
uintptr_t *table;
};
/**
* HTABLE_INITIALIZER - static initialization for a hash table.
* @name: name of this htable.
* @rehash: hash function to use for rehashing.
* @priv: private argument to @rehash function.
*
* This is useful for setting up static and global hash tables.
*
* Example:
* // For simplicity's sake, say hash value is contents of elem.
* static size_t rehash(const void *elem, void *unused)
* {
* return *(size_t *)elem;
* }
* static struct htable ht = HTABLE_INITIALIZER(ht, rehash, NULL);
*/
#define HTABLE_INITIALIZER(name, rehash, priv) \
{ rehash, priv, 0, 0, 0, 0, 0, -1, 0, 0, &name.perfect_bit }
/**
* htable_init - initialize an empty hash table.
* @ht: the hash table to initialize
* @rehash: hash function to use for rehashing.
* @priv: private argument to @rehash function.
*/
void htable_init(struct htable *ht,
size_t (*rehash)(const void *elem, void *priv), void *priv);
/**
* htable_clear - empty a hash table.
* @ht: the hash table to clear
*
* This doesn't do anything to any pointers left in it.
*/
void htable_clear(struct htable *ht);
/**
* htable_rehash - use a hashtree's rehash function
* @elem: the argument to rehash()
*
*/
size_t htable_rehash(const void *elem);
/**
* htable_add - add a pointer into a hash table.
* @ht: the htable
* @hash: the hash value of the object
* @p: the non-NULL pointer
*
* Also note that this can only fail due to allocation failure. Otherwise, it
* returns true.
*/
bool htable_add(struct htable *ht, size_t hash, const void *p);
/**
* htable_del - remove a pointer from a hash table
* @ht: the htable
* @hash: the hash value of the object
* @p: the pointer
*
* Returns true if the pointer was found (and deleted).
*/
bool htable_del(struct htable *ht, size_t hash, const void *p);
/**
* struct htable_iter - iterator or htable_first or htable_firstval etc.
*
* This refers to a location inside the hashtable.
*/
struct htable_iter {
size_t off;
};
/**
* htable_firstval - find a candidate for a given hash value
* @htable: the hashtable
* @i: the struct htable_iter to initialize
* @hash: the hash value
*
* You'll need to check the value is what you want; returns NULL if none.
* See Also:
* htable_delval()
*/
void *htable_firstval(const struct htable *htable,
struct htable_iter *i, size_t hash);
/**
* htable_nextval - find another candidate for a given hash value
* @htable: the hashtable
* @i: the struct htable_iter to initialize
* @hash: the hash value
*
* You'll need to check the value is what you want; returns NULL if no more.
*/
void *htable_nextval(const struct htable *htable,
struct htable_iter *i, size_t hash);
/**
* htable_get - find an entry in the hash table
* @ht: the hashtable
* @h: the hash value of the entry
* @cmp: the comparison function
* @ptr: the pointer to hand to the comparison function.
*
* Convenient inline wrapper for htable_firstval/htable_nextval loop.
*/
static inline void *htable_get(const struct htable *ht,
size_t h,
bool (*cmp)(const void *candidate, void *ptr),
const void *ptr)
{
struct htable_iter i;
void *c;
for (c = htable_firstval(ht,&i,h); c; c = htable_nextval(ht,&i,h)) {
if (cmp(c, (void *)ptr))
return c;
}
return NULL;
}
/**
* htable_first - find an entry in the hash table
* @ht: the hashtable
* @i: the struct htable_iter to initialize
*
* Get an entry in the hashtable; NULL if empty.
*/
void *htable_first(const struct htable *htable, struct htable_iter *i);
/**
* htable_next - find another entry in the hash table
* @ht: the hashtable
* @i: the struct htable_iter to use
*
* Get another entry in the hashtable; NULL if all done.
* This is usually used after htable_first or prior non-NULL htable_next.
*/
void *htable_next(const struct htable *htable, struct htable_iter *i);
/**
* htable_delval - remove an iterated pointer from a hash table
* @ht: the htable
* @i: the htable_iter
*
* Usually used to delete a hash entry after it has been found with
* htable_firstval etc.
*/
void htable_delval(struct htable *ht, struct htable_iter *i);
#endif /* CCAN_HTABLE_H */
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