Tizen Native API
7.0
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These functions manage iterators on containers.
These functions allow accessing elements of a container in a generic way, without knowing which container is used (a bit like iterators in the C++ STL). Iterators only allow sequential access (that is, from one element to the next one). For random access, see Accessor Functions.
Getting an iterator to access elements of a given container is done through the functions of that particular container. There is no function to create a generic iterator as iterators absolutely depend on the container. This means you won't find an iterator creation function here, those can be found with the documentation of the container type you're using. Though created with container specific functions iterators are always deleted with the same function: eina_iterator_free().
To get the data and iterate, use eina_iterator_next(). To call a function on all the elements of a container, use eina_iterator_foreach().
Here an example
Functions | |
void | eina_iterator_free (Eina_Iterator *iterator) |
Frees an iterator. | |
void * | eina_iterator_container_get (Eina_Iterator *iterator) |
Returns the container of an iterator. | |
Eina_Bool | eina_iterator_next (Eina_Iterator *iterator, void **data) |
Returns the value of the current element and go to the next one. | |
void | eina_iterator_foreach (Eina_Iterator *iterator, Eina_Each_Cb callback, const void *fdata) |
Iterates over the container and execute a callback on each element. | |
Eina_Bool | eina_iterator_lock (Eina_Iterator *iterator) |
Locks the container of the iterator. | |
Eina_Bool | eina_iterator_unlock (Eina_Iterator *iterator) |
Unlocks the container of the iterator. | |
Eina_Iterator * | eina_iterator_filter_new (Eina_Iterator *original, Eina_Each_Cb filter, Eina_Free_Cb free_cb, void *data) |
Creates a new iterator which which iterates through all elements with are accepted by the filter callback. | |
Eina_Iterator * | eina_iterator_processed_new (Eina_Iterator *iterator, Eina_Process_Cb process, Eina_Free_Cb free_cb, void *fdata) |
Calls the process method on each node of iterator, producing new "processed" nodes and returning a new iterator which contains them. | |
Typedefs | |
typedef struct _Eina_Iterator | Eina_Iterator |
typedef Eina_Bool(* | Eina_Iterator_Next_Callback )(Eina_Iterator *it, void **data) |
typedef void *(* | Eina_Iterator_Get_Container_Callback )(Eina_Iterator *it) |
typedef void(* | Eina_Iterator_Free_Callback )(Eina_Iterator *it) |
typedef Eina_Bool(* | Eina_Iterator_Lock_Callback )(Eina_Iterator *it) |
Defines | |
#define | FUNC_ITERATOR_NEXT(Function) ((Eina_Iterator_Next_Callback)Function) |
#define | FUNC_ITERATOR_GET_CONTAINER(Function) ((Eina_Iterator_Get_Container_Callback)Function) |
#define | FUNC_ITERATOR_FREE(Function) ((Eina_Iterator_Free_Callback)Function) |
#define | FUNC_ITERATOR_LOCK(Function) ((Eina_Iterator_Lock_Callback)Function) |
#define | EINA_C_ARRAY_ITERATOR_NEW(Array) eina_carray_length_iterator_new((void**) Array, sizeof (Array[0]), EINA_C_ARRAY_LENGTH(Array)) |
Creates an Eina_Iterator that iterates through a NUL-terminated C array. | |
#define | eina_multi_iterator_new(It,...) eina_multi_iterator_internal_new(It, ##__VA_ARGS__, NULL) |
Creates an Eina_Iterator that iterates through a series of Eina_Iterator. | |
#define | EINA_ITERATOR_FOREACH(itr,data) |
Definition for the macro to iterate over all elements easily. |
Define Documentation
#define EINA_C_ARRAY_ITERATOR_NEW | ( | Array | ) | eina_carray_length_iterator_new((void**) Array, sizeof (Array[0]), EINA_C_ARRAY_LENGTH(Array)) |
Creates an Eina_Iterator that iterates through a NUL-terminated C array.
- Parameters:
-
[in] Array The NUL-terminated array
- Returns:
- The iterator that will walk over the array.
You can create it like this: int array[] = {1, 2, 3, 4};
Eina_Iterator* iterator = EINA_C_ARRAY_ITERATOR_NEW(array);
- Since (EFL) :
- 1.22
#define EINA_ITERATOR_FOREACH | ( | itr, | |
data | |||
) |
while (eina_iterator_next((itr), \ (void **)(void *)&(data)))
Definition for the macro to iterate over all elements easily.
- Parameters:
-
[in,out] itr The iterator to use. [out] data Where to store * data, must be a pointer support getting its address since * eina_iterator_next() requires a pointer to pointer!
This macro is a convenient way to use iterators, very similar to EINA_LIST_FOREACH().
This macro can be used for freeing the data of a list, like in the following example. It has the same goal as the one documented in EINA_LIST_FOREACH(), but using iterators:
Eina_List *list; Eina_Iterator *itr; char *data; // list is already filled, // its elements are just duplicated strings itr = eina_list_iterator_new(list); EINA_ITERATOR_FOREACH(itr, data) free(data); eina_iterator_free(itr); eina_list_free(list);
- Note:
- This example is not optimal algorithm to release a list since it will walk the list twice, but it serves as an example. For optimized version use EINA_LIST_FREE()
- Warning:
- The order in which the elements will be traversed depends on the underlying container and shouldn't be relied upon.
- unless explicitly stated in functions returning iterators, do not modify the iterated object while you walk it, in this example using lists, do not remove list nodes or you might crash! This is not a limitation of iterators themselves, rather in the iterators implementations to keep them as simple and fast as possible.
- Examples:
- ecore_thread_example.c, eina_file_01.c, eina_list_03.c, and eina_tiler_01.c.
#define eina_multi_iterator_new | ( | It, | |
... | |||
) | eina_multi_iterator_internal_new(It, ##__VA_ARGS__, NULL) |
Creates an Eina_Iterator that iterates through a series of Eina_Iterator.
- Parameters:
-
[in] It The first Eina_Iterator to iterate over
- Returns:
- The iterator that will walk all the other iterator
Eina_Iterator* iterator = eina_multi_iterator_new(it1, it2, it3);
- Note:
- The returned array will destroy iterator given to it once they are not necessary anymore. Taking ownership of those iterator.
- Since (EFL) :
- 1.22
#define FUNC_ITERATOR_FREE | ( | Function | ) | ((Eina_Iterator_Free_Callback)Function) |
Helper macro to cast Function
to a Eina_Iterator_Free_Callback.
#define FUNC_ITERATOR_GET_CONTAINER | ( | Function | ) | ((Eina_Iterator_Get_Container_Callback)Function) |
Helper macro to cast Function
to a Eina_Iterator_Get_Container_Callback.
#define FUNC_ITERATOR_LOCK | ( | Function | ) | ((Eina_Iterator_Lock_Callback)Function) |
Helper macro to cast Function
to a Eina_Iterator_Lock_Callback.
#define FUNC_ITERATOR_NEXT | ( | Function | ) | ((Eina_Iterator_Next_Callback)Function) |
Helper macro to cast Function
to a Eina_Iterator_Next_Callback.
Typedef Documentation
Abstract type for iterators.
Type for a callback that frees the container.
Type for a callback that returns the container.
Type for a callback that lock the container.
Type for a callback that returns the next element in a container.
Function Documentation
void* eina_iterator_container_get | ( | Eina_Iterator * | iterator | ) |
Returns the container of an iterator.
- Parameters:
-
[in] iterator The iterator.
- Returns:
- The container which created the iterator.
This function returns the container which created iterator
. If iterator
is NULL
, this function returns NULL
.
- Since :
- 2.3.1
- Examples:
- eina_iterator_01.c.
Eina_Iterator* eina_iterator_filter_new | ( | Eina_Iterator * | original, |
Eina_Each_Cb | filter, | ||
Eina_Free_Cb | free_cb, | ||
void * | data | ||
) |
Creates a new iterator which which iterates through all elements with are accepted by the filter callback.
- Parameters:
-
[in] original the iterator the use as original set [in] filter if the callback returns true the element from the original set is taken into the the new set. [in] free_cb when the iterator is gone this callback will be called with data as argument [in] data the data which is passed to the filter callback
The iterator is filtered while it is being iterated. The original iterator you pass in here is is then owned and will be freed once the the new iterator is freed.
- Since (EFL) :
- 1.19
void eina_iterator_foreach | ( | Eina_Iterator * | iterator, |
Eina_Each_Cb | callback, | ||
const void * | fdata | ||
) |
Iterates over the container and execute a callback on each element.
- Parameters:
-
[in,out] iterator The iterator. [in] callback The callback called on each iteration. [in] fdata The data passed to the callback.
This function iterates over the elements pointed by iterator
, beginning with the current element. For each element, the callback cb
is called with the data fdata
. If iterator
is NULL
, the function returns immediately. Also, if cb
returns EINA_FALSE, the iteration stops at that point, if cb
returns EINA_TRUE the iteration continues.
- Since :
- 2.3.1
- Examples:
- eina_iterator_01.c.
void eina_iterator_free | ( | Eina_Iterator * | iterator | ) |
Frees an iterator.
- Parameters:
-
[in,out] iterator The iterator to free.
This function frees iterator
if it is not NULL
;
- Since :
- 2.3.1
Eina_Bool eina_iterator_lock | ( | Eina_Iterator * | iterator | ) |
Locks the container of the iterator.
- Parameters:
-
[in,out] iterator The iterator.
- Returns:
- EINA_TRUE on success, EINA_FALSE otherwise.
If the container of the iterator
permits it, it will be locked. When a container is locked calling eina_iterator_foreach() on it will return immediately. If iterator
is NULL
or if a problem occurred, EINA_FALSE is returned, otherwise EINA_TRUE is returned. If the container isn't lockable, it will return EINA_TRUE.
- Warning:
- None of the existing eina data structures are lockable.
- Since :
- 2.3.1
Eina_Bool eina_iterator_next | ( | Eina_Iterator * | iterator, |
void ** | data | ||
) |
Returns the value of the current element and go to the next one.
- Parameters:
-
[in,out] iterator The iterator. [out] data The data of the element.
- Returns:
- EINA_TRUE on success, EINA_FALSE otherwise.
This function returns the value of the current element pointed by iterator
in data
, then goes to the next element. If iterator
is NULL
or if a problem occurred, EINA_FALSE is returned, otherwise EINA_TRUE is returned.
- Since :
- 2.3.1
- Examples:
- eina_hash_01.c, eina_hash_03.c, eina_hash_04.c, eina_hash_05.c, eina_hash_06.c, eina_hash_07.c, and eina_iterator_01.c.
Eina_Iterator* eina_iterator_processed_new | ( | Eina_Iterator * | iterator, |
Eina_Process_Cb | process, | ||
Eina_Free_Cb | free_cb, | ||
void * | fdata | ||
) |
Calls the process method on each node of iterator, producing new "processed" nodes and returning a new iterator which contains them.
- Parameters:
-
[in] iterator Iterator containing the nodes to process. [in] process Method to call on each node. [in] free_cb Method called when all nodes have been processed. It receives "data" as a parameter. [in] fdata Additional data passed to the process method.
Processes every node in the input iterator and returns a new iterator containing the processed nodes. This is akin to a Map function: https://en.wikipedia.org/wiki/Map_(higher-order_function)
- Since (EFL) :
- 1.24
Eina_Bool eina_iterator_unlock | ( | Eina_Iterator * | iterator | ) |
Unlocks the container of the iterator.
- Parameters:
-
[in,out] iterator The iterator.
- Returns:
- EINA_TRUE on success, EINA_FALSE otherwise.
If the container of the iterator
permits it and was previously locked, it will be unlocked. If iterator
is NULL
or if a problem occurred, EINA_FALSE is returned, otherwise EINA_TRUE is returned. If the container is not lockable, it will return EINA_TRUE.
- Warning:
- None of the existing eina data structures are lockable.
- Since :
- 2.3.1