/*
* $Id: linkhash.h,v 1.6 2006/01/30 23:07:57 mclark Exp $
*
* Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
* Michael Clark <michael@metaparadigm.com>
* Copyright (c) 2009 Hewlett-Packard Development Company, L.P.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See COPYING for details.
*
*/
#ifndef _linkhash_h_
#define _linkhash_h_
#include "json_object.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* golden prime used in hash functions
*/
#define LH_PRIME 0x9e370001UL
/**
* The fraction of filled hash buckets until an insert will cause the table
* to be resized.
* This can range from just above 0 up to 1.0.
*/
#define LH_LOAD_FACTOR 0.66
/**
* sentinel pointer value for empty slots
*/
#define LH_EMPTY (void*)-1
/**
* sentinel pointer value for freed slots
*/
#define LH_FREED (void*)-2
struct lh_entry;
/**
* callback function prototypes
*/
typedef void (lh_entry_free_fn) (struct lh_entry *e);
/**
* callback function prototypes
*/
typedef unsigned long (lh_hash_fn) (const void *k);
/**
* callback function prototypes
*/
typedef int (lh_equal_fn) (const void *k1, const void *k2);
/**
* An entry in the hash table
*/
struct lh_entry {
/**
* The key.
*/
void *k;
/**
* The value.
*/
const void *v;
/**
* The next entry
*/
struct lh_entry *next;
/**
* The previous entry.
*/
struct lh_entry *prev;
};
/**
* The hash table structure.
*/
struct lh_table {
/**
* Size of our hash.
*/
int size;
/**
* Numbers of entries.
*/
int count;
/**
* Number of collisions.
*/
int collisions;
/**
* Number of resizes.
*/
int resizes;
/**
* Number of lookups.
*/
int lookups;
/**
* Number of inserts.
*/
int inserts;
/**
* Number of deletes.
*/
int deletes;
/**
* Name of the hash table.
*/
const char *name;
/**
* The first entry.
*/
struct lh_entry *head;
/**
* The last entry.
*/
struct lh_entry *tail;
struct lh_entry *table;
/**
* A pointer onto the function responsible for freeing an entry.
*/
lh_entry_free_fn *free_fn;
lh_hash_fn *hash_fn;
lh_equal_fn *equal_fn;
};
/**
* Pre-defined hash and equality functions
*/
extern unsigned long lh_ptr_hash(const void *k);
extern int lh_ptr_equal(const void *k1, const void *k2);
extern unsigned long lh_char_hash(const void *k);
extern int lh_char_equal(const void *k1, const void *k2);
/**
* Convenience list iterator.
*/
#define lh_foreach(table, entry) \
for(entry = table->head; entry; entry = entry->next)
/**
* lh_foreach_safe allows calling of deletion routine while iterating.
*/
#define lh_foreach_safe(table, entry, tmp) \
for(entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)
/**
* Create a new linkhash table.
* @param size initial table size. The table is automatically resized
* although this incurs a performance penalty.
* @param name the table name.
* @param free_fn callback function used to free memory for entries
* when lh_table_free or lh_table_delete is called.
* If NULL is provided, then memory for keys and values
* must be freed by the caller.
* @param hash_fn function used to hash keys. 2 standard ones are defined:
* lh_ptr_hash and lh_char_hash for hashing pointer values
* and C strings respectively.
* @param equal_fn comparison function to compare keys. 2 standard ones defined:
* lh_ptr_hash and lh_char_hash for comparing pointer values
* and C strings respectively.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_table_new(int size, const char *name,
lh_entry_free_fn *free_fn,
lh_hash_fn *hash_fn,
lh_equal_fn *equal_fn);
/**
* Convenience function to create a new linkhash
* table with char keys.
* @param size initial table size.
* @param name table name.
* @param free_fn callback function used to free memory for entries.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_kchar_table_new(int size, const char *name,
lh_entry_free_fn *free_fn);
/**
* Convenience function to create a new linkhash
* table with ptr keys.
* @param size initial table size.
* @param name table name.
* @param free_fn callback function used to free memory for entries.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_kptr_table_new(int size, const char *name,
lh_entry_free_fn *free_fn);
/**
* Free a linkhash table.
* If a callback free function is provided then it is called for all
* entries in the table.
* @param t table to free.
*/
extern void lh_table_free(struct lh_table *t);
/**
* Insert a record into the table.
* @param t the table to insert into.
* @param k a pointer to the key to insert.
* @param v a pointer to the value to insert.
*/
extern int lh_table_insert(struct lh_table *t, void *k, const void *v);
/**
* Lookup a record into the table.
* @param t the table to lookup
* @param k a pointer to the key to lookup
* @return a pointer to the record structure of the value or NULL if it does not exist.
*/
extern struct lh_entry* lh_table_lookup_entry(struct lh_table *t, const void *k);
/**
* Lookup a record into the table
* @param t the table to lookup
* @param k a pointer to the key to lookup
* @return a pointer to the found value or NULL if it does not exist.
* @deprecated Use lh_table_lookup_ex instead.
*/
THIS_FUNCTION_IS_DEPRECATED(extern const void* lh_table_lookup(struct lh_table *t, const void *k));
/**
* Lookup a record in the table
* @param t the table to lookup
* @param k a pointer to the key to lookup
* @param v a pointer to a where to store the found value (set to NULL if it doesn't exist).
* @return whether or not the key was found
*/
extern json_bool lh_table_lookup_ex(struct lh_table *t, const void *k, void **v);
/**
* Delete a record from the table.
* If a callback free function is provided then it is called for the
* for the item being deleted.
* @param t the table to delete from.
* @param e a pointer to the entry to delete.
* @return 0 if the item was deleted.
* @return -1 if it was not found.
*/
extern int lh_table_delete_entry(struct lh_table *t, struct lh_entry *e);
/**
* Delete a record from the table.
* If a callback free function is provided then it is called for the
* for the item being deleted.
* @param t the table to delete from.
* @param k a pointer to the key to delete.
* @return 0 if the item was deleted.
* @return -1 if it was not found.
*/
extern int lh_table_delete(struct lh_table *t, const void *k);
extern int lh_table_length(struct lh_table *t);
void lh_abort(const char *msg, ...);
void lh_table_resize(struct lh_table *t, int new_size);
#ifdef __cplusplus
}
#endif
#endif