linkhash.h File Reference

Data Structures
struct	lh_entry
struct	lh_table

Macros
#define	LH_PRIME   0x9e370001UL
#define	LH_LOAD_FACTOR   0.66
#define	LH_EMPTY   (void*)-1
#define	LH_FREED   (void*)-2
#define	lh_foreach(table, entry)   for(entry = table->head; entry; entry = entry->next)
#define	lh_foreach_safe(table, entry, tmp)   for(entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)

Typedefs
typedef void(	lh_entry_free_fn )(struct lh_entry *e)
typedef unsigned long(	lh_hash_fn )(const void *k)
typedef int(	lh_equal_fn )(const void *k1, const void *k2)

Functions
unsigned long	lh_ptr_hash (const void *k)
int	lh_ptr_equal (const void *k1, const void *k2)
unsigned long	lh_char_hash (const void *k)
int	lh_char_equal (const void *k1, const void *k2)
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)
struct lh_table *	lh_kchar_table_new (int size, const char *name, lh_entry_free_fn *free_fn)
struct lh_table *	lh_kptr_table_new (int size, const char *name, lh_entry_free_fn *free_fn)
void	lh_table_free (struct lh_table *t)
int	lh_table_insert (struct lh_table *t, void *k, const void *v)
struct lh_entry *	lh_table_lookup_entry (struct lh_table *t, const void *k)
	THIS_FUNCTION_IS_DEPRECATED (extern const void *lh_table_lookup(struct lh_table *t, const void *k))
json_bool	lh_table_lookup_ex (struct lh_table *t, const void *k, void **v)
int	lh_table_delete_entry (struct lh_table *t, struct lh_entry *e)
int	lh_table_delete (struct lh_table *t, const void *k)
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)

Macro Definition Documentation

#define LH_EMPTY   (void*)-1

sentinel pointer value for empty slots

#define lh_foreach	(		table,
			entry
	)		for(entry = table->head; entry; entry = entry->next)

Convenience list iterator.

#define lh_foreach_safe	(		table,
			entry,
			tmp
	)		for(entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)

lh_foreach_safe allows calling of deletion routine while iterating.

#define LH_FREED   (void*)-2

sentinel pointer value for freed slots

#define LH_LOAD_FACTOR   0.66

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_PRIME   0x9e370001UL

golden prime used in hash functions

Typedef Documentation

typedef void( lh_entry_free_fn)(struct lh_entry *e)

callback function prototypes

typedef int( lh_equal_fn)(const void *k1, const void *k2)

callback function prototypes

typedef unsigned long( lh_hash_fn)(const void *k)

callback function prototypes

Function Documentation

void lh_abort	(	const char *	msg,
			...
	)

int lh_char_equal	(	const void *	k1,
		const void *	k2
	)

unsigned long lh_char_hash

(

const void *

k

)

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 char keys.

Parameters

size	initial table size.
name	table name.
free_fn	callback function used to free memory for entries.

Returns

a pointer onto the linkhash table.

struct lh_table* lh_kptr_table_new	(	int	size,
		const char *	name,
		lh_entry_free_fn *	free_fn
	)

Convenience function to create a new linkhash table with ptr keys.

Parameters

size	initial table size.
name	table name.
free_fn	callback function used to free memory for entries.

Returns

a pointer onto the linkhash table.

int lh_ptr_equal	(	const void *	k1,
		const void *	k2
	)

unsigned long lh_ptr_hash

(

const void *

k

)

Pre-defined hash and equality functions

int lh_table_delete	(	struct lh_table *	t,
		const void *	k
	)

Delete a record from the table. If a callback free function is provided then it is called for the for the item being deleted.

Parameters

t	the table to delete from.
k	a pointer to the key to delete.

Returns

0 if the item was deleted.

-1 if it was not found.

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.

Parameters

t	the table to delete from.
e	a pointer to the entry to delete.

Returns

0 if the item was deleted.

-1 if it was not found.

void lh_table_free

(

struct lh_table *

t

)

Free a linkhash table. If a callback free function is provided then it is called for all entries in the table.

Parameters

t	table to free.

int lh_table_insert	(	struct lh_table *	t,
		void *	k,
		const void *	v
	)

Insert a record into the table.

Parameters

t	the table to insert into.
k	a pointer to the key to insert.
v	a pointer to the value to insert.

int lh_table_length

(

struct lh_table *

t

)

struct lh_entry* lh_table_lookup_entry	(	struct lh_table *	t,
		const void *	k
	)

Lookup a record into the table.

Parameters

t	the table to lookup
k	a pointer to the key to lookup

Returns

a pointer to the record structure of the value or NULL if it does not exist.

json_bool lh_table_lookup_ex	(	struct lh_table *	t,
		const void *	k,
		void **	v
	)

Lookup a record in the table

Parameters

t	the table to lookup
k	a pointer to the key to lookup
v	a pointer to a where to store the found value (set to NULL if it doesn't exist).

Returns

whether or not the key was found

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
	)

Create a new linkhash table.

Parameters

size	initial table size. The table is automatically resized although this incurs a performance penalty.
name	the table name.
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.
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.
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.

Returns

a pointer onto the linkhash table.

void lh_table_resize	(	struct lh_table *	t,
		int	new_size
	)

THIS_FUNCTION_IS_DEPRECATED

(

extern const void *

lh_table_lookupstruct lh_table *t, const void *k

)

Lookup a record into the table

Parameters

t	the table to lookup
k	a pointer to the key to lookup

Returns

a pointer to the found value or NULL if it does not exist.

Deprecated:

Use lh_table_lookup_ex instead.