Hash Table
[Containers]

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Data Structures
struct	_Eina_Hash_Tuple
Defines
#define	EINA_KEY_LENGTH(Function) ((Eina_Key_Length)Function)
#define	EINA_KEY_CMP(Function) ((Eina_Key_Cmp)Function)
#define	EINA_KEY_HASH(Function) ((Eina_Key_Hash)Function)
Typedefs
typedef struct _Eina_Hash	Eina_Hash
	Type for a generic hash table.
typedef struct _Eina_Hash_Tuple	Eina_Hash_Tuple
typedef unsigned int(*	Eina_Key_Length )(const void *key)
typedef int(*	Eina_Key_Cmp )(const void key1, int key1_length, const void key2, int key2_length)
typedef int(*	Eina_Key_Hash )(const void *key, int key_length)
typedef Eina_Bool(*	Eina_Hash_Foreach )(const Eina_Hash hash, const void key, void data, void fdata)
Functions
Eina_Hash *	eina_hash_new (Eina_Key_Length key_length_cb, Eina_Key_Cmp key_cmp_cb, Eina_Key_Hash key_hash_cb, Eina_Free_Cb data_free_cb, int buckets_power_size)
	Create a new hash table.
Eina_Hash *	eina_hash_string_djb2_new (Eina_Free_Cb data_free_cb)
	Create a new hash table using the djb2 algorithm.
Eina_Hash *	eina_hash_string_superfast_new (Eina_Free_Cb data_free_cb)
	Create a new hash table for use with strings.
Eina_Hash *	eina_hash_string_small_new (Eina_Free_Cb data_free_cb)
	Create a new hash table for use with strings with small bucket size.
Eina_Hash *	eina_hash_int32_new (Eina_Free_Cb data_free_cb)
	Create a new hash table for use with 32bit integers.
Eina_Hash *	eina_hash_int64_new (Eina_Free_Cb data_free_cb)
	Create a new hash table for use with 64bit integers.
Eina_Hash *	eina_hash_pointer_new (Eina_Free_Cb data_free_cb)
	Create a new hash table for use with pointers.
Eina_Hash *	eina_hash_stringshared_new (Eina_Free_Cb data_free_cb)
	Create a new hash table optimized for stringshared values.
Eina_Bool	eina_hash_add (Eina_Hash hash, const void key, const void *data)
	Add an entry to the given hash table.
Eina_Bool	eina_hash_direct_add (Eina_Hash hash, const void key, const void *data)
	Add an entry to the given hash table without duplicating the string key.
Eina_Bool	eina_hash_del (Eina_Hash hash, const void key, const void *data)
	Remove the entry identified by a key or a data from the given hash table.
void *	eina_hash_find (const Eina_Hash hash, const void key)
	Retrieve a specific entry in the given hash table.
void *	eina_hash_modify (Eina_Hash hash, const void key, const void *data)
	Modify the entry pointer at the specified key and return the old entry.
void *	eina_hash_set (Eina_Hash hash, const void key, const void *data)
	Modify the entry pointer at the specified key and return the old entry or add the entry if not found.
Eina_Bool	eina_hash_move (Eina_Hash hash, const void old_key, const void *new_key)
	Change the key associated with a data without triggering the free callback.
void	eina_hash_free (Eina_Hash *hash)
	Free the given hash table resources.
void	eina_hash_free_buckets (Eina_Hash *hash)
	Free the given hash table buckets resources.
int	eina_hash_population (const Eina_Hash *hash)
	Returns the number of entries in the given hash table.
Eina_Bool	eina_hash_add_by_hash (Eina_Hash hash, const void key, int key_length, int key_hash, const void *data)
	Add an entry to the given hash table.
Eina_Bool	eina_hash_direct_add_by_hash (Eina_Hash hash, const void key, int key_length, int key_hash, const void *data)
	Add an entry to the given hash table and do not duplicate the string key.
Eina_Bool	eina_hash_del_by_key_hash (Eina_Hash hash, const void key, int key_length, int key_hash)
	Remove the entry identified by a key and a key hash from the given hash table.
Eina_Bool	eina_hash_del_by_key (Eina_Hash hash, const void key)
	Remove the entry identified by a key from the given hash table.
Eina_Bool	eina_hash_del_by_data (Eina_Hash hash, const void data)
	Remove the entry identified by a data from the given hash table.
Eina_Bool	eina_hash_del_by_hash (Eina_Hash hash, const void key, int key_length, int key_hash, const void *data)
	Remove the entry identified by a key and a key hash or a data from the given hash table.
void *	eina_hash_find_by_hash (const Eina_Hash hash, const void key, int key_length, int key_hash)
	Retrieve a specific entry in the given hash table.
void *	eina_hash_modify_by_hash (Eina_Hash hash, const void key, int key_length, int key_hash, const void *data)
	Modify the entry pointer at the specified key and returns the old entry.
Eina_Iterator *	eina_hash_iterator_key_new (const Eina_Hash *hash)
	Returned a new iterator associated to hash keys.
Eina_Iterator *	eina_hash_iterator_data_new (const Eina_Hash *hash)
	Returned a new iterator associated to hash data.
Eina_Iterator *	eina_hash_iterator_tuple_new (const Eina_Hash *hash)
	Returned a new iterator associated to hash keys and data.
void	eina_hash_foreach (const Eina_Hash hash, Eina_Hash_Foreach func, const void fdata)
	Call a function on every member stored in the hash table.
int	eina_hash_superfast (const char *key, int len)
static int	eina_hash_djb2 (const char *key, int len)
static int	eina_hash_djb2_len (const char key, int plen)
static int	eina_hash_int32 (const unsigned int *pkey, int len)
static int	eina_hash_int64 (const unsigned long int *pkey, int len)

Detailed Description

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..

Hash API. Give some hints about the use (functions that must be used like init / shutdown), general use, etc... Give also a link to tutorial below.

Algorithm

Give here the algorithm used in the implementation

Performance

Give some hints about performance if it is possible, and an image !

Tutorial

Here is a fantastic tutorial about our hash table

Function Documentation

Eina_Hash * eina_hash_new	(	Eina_Key_Length	key_length_cb,
		Eina_Key_Cmp	key_cmp_cb,
		Eina_Key_Hash	key_hash_cb,
		Eina_Free_Cb	data_free_cb,
		int	buckets_power_size
	)

Create a new hash table.

Parameters:

	key_length_cb	The function called when getting the size of the key.
	key_cmp_cb	The function called when comparing the keys.
	key_hash_cb	The function called when getting the values.
	data_free_cb	The function called when the hash table is freed.
	buckets_power_size	The size of the buckets.

Returns:: The new hash table.

This function create a new hash table using user-defined callbacks to manage the hash table. On failure, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. If key_cmp_cb or key_hash_cb are NULL, NULL is returned. If buckets_power_size is smaller or equal than 2, or if it is greater or equal than 17, NULL is returned.

Pre-defined functions are available to create a hash table. See eina_hash_string_djb2_new(), eina_hash_string_superfast_new(), eina_hash_string_small_new(), eina_hash_int32_new(), eina_hash_int64_new(), eina_hash_pointer_new() and eina_hash_stringshared_new().

Eina_Hash * eina_hash_string_djb2_new ( Eina_Free_Cb data_free_cb )

Create a new hash table using the djb2 algorithm.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the djb2 algorithm for table management and strcmp() to compare the keys. Values can then be looked up with pointers other than the original key pointer that was used to add values. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_string_superfast_new ( Eina_Free_Cb data_free_cb )

Create a new hash table for use with strings.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the superfast algorithm for table management and strcmp() to compare the keys. Values can then be looked up with pointers other than the original key pointer that was used to add values. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_string_small_new ( Eina_Free_Cb data_free_cb )

Create a new hash table for use with strings with small bucket size.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the superfast algorithm for table management and strcmp() to compare the keys, but with a smaller bucket size (compared to eina_hash_string_superfast_new()) which will minimize the memory used by the returned hash table. Values can then be looked up with pointers other than the original key pointer that was used to add values. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_int32_new ( Eina_Free_Cb data_free_cb )

Create a new hash table for use with 32bit integers.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the int32 algorithm for table management and dereferenced pointers to compare the keys. Values can then be looked up with pointers other than the original key pointer that was used to add values. This method may appear to be able to match string keys, actually it only matches the first character. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_int64_new ( Eina_Free_Cb data_free_cb )

Create a new hash table for use with 64bit integers.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the int64 algorithm for table management and dereferenced pointers to compare the keys. Values can then be looked up with pointers other than the original key pointer that was used to add values. This method may appear to be able to match string keys, actually it only matches the first character. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_pointer_new ( Eina_Free_Cb data_free_cb )

Create a new hash table for use with pointers.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table using the int64 algorithm for table management and dereferenced pointers to compare the keys. Values can then be looked up with pointers other than the original key pointer that was used to add values. This method may appear to be able to match string keys, actually it only matches the first character. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Eina_Hash * eina_hash_stringshared_new ( Eina_Free_Cb data_free_cb )

Create a new hash table optimized for stringshared values.

Parameters:

data_free_cb

The function called when the hash table is freed.

Returns:: The new hash table.

This function create a new hash table optimized for stringshared values. Values CAN NOT be looked up with pointers not equal to the original key pointer that was used to add a value. On failure, this function returns NULL. data_free_cb is a callback called when the hash table is freed. NULL can be passed as callback.

Excerpt of code that will NOT work with this type of hash:

 extern Eina_Hash *hash;
 extern const char *value;
 const char *a = eina_stringshare_add("key");

 eina_hash_add(hash, a, value);
 eina_hash_find(hash, "key")

Eina_Bool eina_hash_add	(	Eina_Hash *	hash,
		const void *	key,
		const void *	data
	)

Add an entry to the given hash table.

Parameters:

	hash	The given hash table.
	key	A unique key.
	data	Data to associate with the string given by `key`.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function adds key to hash. hash, key and data can be NULL, in that case EINA_FALSE is returned. key is expected to be unique within the hash table. Key uniqueness varies depending on the type of hash: a stringshared Eina_Hash need only have unique pointers for keys, but the strings in the pointers may be identical. All other hash types require the strings themselves to be unique. Failure to use sufficient uniqueness will result in unexpected results when inserting data pointers accessed with eina_hash_find(), and removed with eina_hash_del(). Key strings are case sensitive. If an error occurs, eina_error_get() should be used to determine if an allocation error occurred during this function. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Eina_Bool eina_hash_direct_add	(	Eina_Hash *	hash,
		const void *	key,
		const void *	data
	)

Add an entry to the given hash table without duplicating the string key.

Parameters:

	hash	The given hash table. Can be `NULL`.
	key	A unique key. Can be `NULL`.
	data	Data to associate with the string given by `key`.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function adds key to hash. hash, key and data can be NULL, in that case EINA_FALSE is returned. key is expected to be unique within the hash table. Key uniqueness varies depending on the type of hash: a stringshared Eina_Hash need only have unique pointers for keys, but the strings in the pointers may be identical. All other hash types require the strings themselves to be unique. Failure to use sufficient uniqueness will result in unexpected results when inserting data pointers accessed with eina_hash_find(), and removed with eina_hash_del(). This function does not make a copy of key, so it must be a string constant or stored elsewhere ( in the object being added). Key strings are case sensitive. If an error occurs, eina_error_get() should be used to determine if an allocation error occurred during this function. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Eina_Bool eina_hash_del	(	Eina_Hash *	hash,
		const void *	key,
		const void *	data
	)

Remove the entry identified by a key or a data from the given hash table.

Parameters:

	hash	The given hash table.
	key	The key.
	data	The data pointer to remove if the key is `NULL`.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function removes the entry identified by key or data from hash. If a free function was given to the callback on creation, it will be called for the data being deleted. If hash is NULL, the functions returns immediately EINA_FALSE. If key is NULL, then data is used to find the a match to remove, otherwise key is used and data is not required and can be NULL. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Note:: if you know you already have the key, use eina_hash_del_by_key() or eina_hash_del_by_key_hash(). If you know you don't have the key, use eina_hash_del_by_data() directly.

void * eina_hash_find	(	const Eina_Hash *	hash,
		const void *	key
	)

Retrieve a specific entry in the given hash table.

Parameters:

	hash	The given hash table.
	key	The key of the entry to find.

Returns:: The data pointer for the stored entry on success, NULL otherwise.

This function retrieves the entry associated to key in hash. If hash is NULL, this function returns immediately NULL. This function returns the data pointer on success, NULL otherwise.

void * eina_hash_modify	(	Eina_Hash *	hash,
		const void *	key,
		const void *	data
	)

Modify the entry pointer at the specified key and return the old entry.

Parameters:

	hash	The given hash table.
	key	The key of the entry to modify.
	data	The data to replace the old entry.

Returns:: The data pointer for the old stored entry on success, or NULL otherwise.

This function modifies the data of key with data in hash. If no entry is found, nothing is added to hash. On success this function returns the old entry, otherwise it returns NULL.

void * eina_hash_set	(	Eina_Hash *	hash,
		const void *	key,
		const void *	data
	)

Modify the entry pointer at the specified key and return the old entry or add the entry if not found.

Parameters:

	hash	The given hash table.
	key	The key of the entry to modify.
	data	The data to replace the old entry

Returns:: The data pointer for the old stored entry, or NULL otherwise.

This function modifies the data of key with data in hash. If no entry is found, data is added to hash with the key key. On success this function returns the old entry, otherwise it returns NULL. To check for errors, use eina_error_get().

Eina_Bool eina_hash_move	(	Eina_Hash *	hash,
		const void *	old_key,
		const void *	new_key
	)

Change the key associated with a data without triggering the free callback.

Parameters:

	hash	The given hash table.
	old_key	The current key associated with the data
	new_key	The new key to associate data with

Returns:: EINA_FALSE in any case but success, EINA_TRUE on success.

This function allows for the move of data from one key to another, but does not call the Eina_Free_Cb associated with the hash table when destroying the old key.

void eina_hash_free ( Eina_Hash * hash )

Free the given hash table resources.

Parameters:

hash

The hash table to be freed.

This function frees up all the memory allocated to storing hash, and call the free callback if it has been passed to the hash table at creation time. If no free callback has been passed, any entries in the table that the program has no more pointers for elsewhere may now be lost, so this should only be called if the program has already freed any allocated data in the hash table or has the pointers for data in the table stored elsewhere as well. If hash is NULL, the function returns immediately.

Example:

 extern Eina_Hash *hash;

 eina_hash_free(hash);
 hash = NULL;

void eina_hash_free_buckets ( Eina_Hash * hash )

Free the given hash table buckets resources.

Parameters:

hash

The hash table whose buckets have to be freed.

This function frees up all the memory allocated to storing the buckets of hash, and call the free callback on all hash table buckets if it has been passed to the hash table at creation time, then frees the buckets. If no free callback has been passed, no buckets value will be freed. If hash is NULL, the function returns immediately.

int eina_hash_population ( const Eina_Hash * hash )

Returns the number of entries in the given hash table.

Parameters:

hash

The given hash table.

Returns:: The number of entries in the hash table.

This function returns the number of entries in hash, or 0 on error. If hash is NULL, 0 is returned.

Eina_Bool eina_hash_add_by_hash	(	Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash,
		const void *	data
	)

Add an entry to the given hash table.

Parameters:

	hash	The given hash table.
	key	A unique key.
	key_length	The length of the key.
	key_hash	The hash that will always match key.
	data	The data to associate with the string given by the key.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function adds key to hash. hash, key and data can be NULL, in that case EINA_FALSE is returned. key is expected to be a unique string within the hash table. Otherwise, one cannot be sure which inserted data pointer will be accessed with eina_hash_find, and removed with eina_hash_del. Do not forget to count '\0' for string when setting the value of key_length. key_hash is expected to always match key. Otherwise, one cannot be sure to find it again with eina_hash_find_by_hash. Key strings are case sensitive. If an error occurs, eina_error_get() should be used to determine if an allocation error occurred during this function. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Eina_Bool eina_hash_direct_add_by_hash	(	Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash,
		const void *	data
	)

Add an entry to the given hash table and do not duplicate the string key.

Parameters:

	hash	The given hash table. Can be `NULL`.
	key	A unique key. Can be `NULL`.
	key_length	Should be the length of `key` (don't forget to count '\0' for string).
	key_hash	The hash that will always match key.
	data	Data to associate with the string given by `key`.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function adds key to hash. hash, key and data can be NULL, in that case EINA_FALSE is returned. key is expected to be a unique string within the hash table. Otherwise, one cannot be sure which inserted data pointer will be accessed with eina_hash_find, and removed with eina_hash_del. This function does not make a copy of key so it must be a string constant or stored elsewhere (in the object being added). Do not forget to count '\0' for string when setting the value of key_length. key_hash is expected to always match key. Otherwise, one cannot be sure to find it again with eina_hash_find_by_hash. Key strings are case sensitive. If an error occurs, eina_error_get() should be used to determine if an allocation error occurred during this function. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Eina_Bool eina_hash_del_by_key_hash	(	Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash
	)

Remove the entry identified by a key and a key hash from the given hash table.

Parameters:

	hash	The given hash table.
	key	The key.
	key_length	The length of the key.
	key_hash	The hash that always match the key.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function removes the entry identified by key and key_hash from hash. If a free function was given to the callback on creation, it will be called for the data being deleted. Do not forget to count '\0' for string when setting the value of key_length. If hash or key are NULL, the functions returns immediately EINA_FALSE. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Note:: if you don't have the key_hash, use eina_hash_del_by_key() instead.; if you don't have the key, use eina_hash_del_by_data() instead.

Eina_Bool eina_hash_del_by_key	(	Eina_Hash *	hash,
		const void *	key
	)

Remove the entry identified by a key from the given hash table.

This version will calculate key length and hash by using functions provided to hash creation function.

Parameters:

	hash	The given hash table.
	key	The key.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function removes the entry identified by key from hash. The key length and hash will be calculated automatically by using functiond provided to has creation function. If a free function was given to the callback on creation, it will be called for the data being deleted. If hash or key are NULL, the functions returns immediately EINA_FALSE. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Note:: if you already have the key_hash, use eina_hash_del_by_key_hash() instead.; if you don't have the key, use eina_hash_del_by_data() instead.

Eina_Bool eina_hash_del_by_data	(	Eina_Hash *	hash,
		const void *	data
	)

Remove the entry identified by a data from the given hash table.

This version is slow since there is no quick access to nodes based on data.

Parameters:

	hash	The given hash table.
	data	The data value to search and remove.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise. thing goes fine.

This function removes the entry identified by data from hash. If a free function was given to the callback on creation, it will be called for the data being deleted. If hash or data are NULL, the functions returns immediately EINA_FALSE. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Note:: if you already have the key, use eina_hash_del_by_key() or eina_hash_del_by_key_hash() instead.

Eina_Bool eina_hash_del_by_hash	(	Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash,
		const void *	data
	)

Remove the entry identified by a key and a key hash or a data from the given hash table.

If key is NULL, then data is used to find a match to remove.

Parameters:

	hash	The given hash table.
	key	The key.
	key_length	The length of the key.
	key_hash	The hash that always match the key.
	data	The data pointer to remove if the key is `NULL`.

Returns:: EINA_FALSE if an error occurred, EINA_TRUE otherwise.

This function removes the entry identified by key and key_hash, or data, from hash. If a free function was given to the callback on creation, it will be called for the data being deleted. If hash is NULL, the functions returns immediately EINA_FALSE. If key is NULL, then key_hash and key_hash are ignored and data is used to find a match to remove, otherwise key and key_hash are used and data is not required and can be NULL. Do not forget to count '\0' for string when setting the value of key_length. This function returns EINA_FALSE if an error occurred, EINA_TRUE otherwise.

Note:: if you know you already have the key, use eina_hash_del_by_key_hash(), if you know you don't have the key, use eina_hash_del_by_data() directly.

void * eina_hash_find_by_hash	(	const Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash
	)

Retrieve a specific entry in the given hash table.

Parameters:

	hash	The given hash table.
	key	The key of the entry to find.
	key_length	The length of the key.
	key_hash	The hash that always match the key

Returns:: The data pointer for the stored entry on success, NULL otherwise.

This function retrieves the entry associated to key of length key_length in hash. key_hash is the hash that always match key. It is ignored if key is NULL. Do not forget to count '\0' for string when setting the value of key_length. If hash is NULL, this function returns immediately NULL. This function returns the data pointer on success, NULL otherwise.

void * eina_hash_modify_by_hash	(	Eina_Hash *	hash,
		const void *	key,
		int	key_length,
		int	key_hash,
		const void *	data
	)

Modify the entry pointer at the specified key and returns the old entry.

Parameters:

	hash	The given hash table.
	key	The key of the entry to modify.
	key_length	Should be the length of `key` (don't forget to count '\0' for string).
	key_hash	The hash that always match the key. Ignored if `key` is `NULL`.
	data	The data to replace the old entry, if it exists.

Returns:: The data pointer for the old stored entry, or NULL if not found. If an existing entry is not found, nothing is added to the hash.

Eina_Iterator * eina_hash_iterator_key_new ( const Eina_Hash * hash )

Returned a new iterator associated to hash keys.

Parameters:

hash

The hash.

Returns:: A new iterator.

This function returns a newly allocated iterator associated to hash. If hash is not populated, this function still returns a valid iterator that will always return false on eina_iterator_next(), thus keeping API sane.

If the memory can not be allocated, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid iterator is returned.

Warning:: if the hash structure changes then the iterator becomes invalid! That is, if you add or remove items this iterator behavior is undefined and your program may crash!

Eina_Iterator * eina_hash_iterator_data_new ( const Eina_Hash * hash )

Returned a new iterator associated to hash data.

Parameters:

hash

The hash.

Returns:: A new iterator.

This function returns a newly allocated iterator associated to hash. If hash is not populated, this function still returns a valid iterator that will always return false on eina_iterator_next(), thus keeping API sane.

If the memory can not be allocated, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid iterator is returned.

Warning:: if the hash structure changes then the iterator becomes invalid. That is, if you add or remove items this iterator behavior is undefined and your program may crash.

Eina_Iterator * eina_hash_iterator_tuple_new ( const Eina_Hash * hash )

Returned a new iterator associated to hash keys and data.

Parameters:

hash

The hash.

Returns:: A new iterator.

This function returns a newly allocated iterator associated to hash. If hash is not populated, this function still returns a valid iterator that will always return false on eina_iterator_next(), thus keeping API sane.

If the memory can not be allocated, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid iterator is returned.

Note:: iterator data will provide values as Eina_Hash_Tuple that should not be modified!

Warning:: if the hash structure changes then the iterator becomes invalid! That is, if you add or remove items this iterator behavior is undefined and your program may crash!

void eina_hash_foreach	(	const Eina_Hash *	hash,
		Eina_Hash_Foreach	func,
		const void *	fdata
	)

Call a function on every member stored in the hash table.

Parameters:

	hash	The hash table whose members will be walked
	func	The function to call on each parameter
	fdata	The data pointer to pass to the function being called

This function goes through every entry in the hash table hash and calls the function func on each member. The function should not modify the hash table contents if it returns 1. If the hash table contents are modified by this function or the function wishes to stop processing it must return 0, otherwise return 1 to keep processing.

Example:

 extern Eina_Hash *hash;

 Eina_Bool hash_fn(const Eina_Hash *hash, const void *key, void *data, void *fdata)
 {
   printf("Func data: %s, Hash entry: %s / %p\n", fdata, (const char *)key, data);
   return 1;
 }

 int main(int argc, char **argv)
 {
   char *hash_fn_data;

   hash_fn_data = strdup("Hello World");
   eina_hash_foreach(hash, hash_fn, hash_fn_data);
   free(hash_fn_data);
 }

Enlightenment

Beauty at your fingertips

Hash Table
[Containers]

Data Structures

Defines

Typedefs

Functions

Detailed Description

Algorithm

Performance

Tutorial

Function Documentation

Enlightenment

Beauty at your fingertips

Hash Table [Containers]

Data Structures

Defines

Typedefs

Functions

Detailed Description

Algorithm

Performance

Tutorial

Function Documentation

Hash Table
[Containers]