This group discusses the functions to provide array management.

The Array data type in Eina is designed to have very fast access to its data (compared to the Eina List). On the other hand, data can be added or removed only at the end of the array. To insert data at any place, the Eina List is the correct container to use.

An array must be created with eina_array_new(). It allocates all the necessary data for an array. When not needed anymore, an array is freed with eina_array_free(). This function does not free any allocated memory used to store the data of each element. For that, just iterate over the array to free them. A convenient way to do that is by using EINA_ARRAY_ITER_NEXT. An example of code is given in the description of this macro.

Functions do not check if the used array is valid or not. It's up to the user to be sure of that. It is designed like that for performance reasons.

The usual features of an array are classic ones: to append an element, use eina_array_push() and to remove the last element, use eina_array_pop(). To retrieve the element at a given position, use eina_array_data_get(). The number of elements can be retrieved with eina_array_count().

Eina_Array is different from a conventional C array in a number of ways, most importantly they grow and shrink dynamically, this means that if you add an element to a full array it grows and when you remove an element from an array it may shrink.

When the array needs to grow it allocates memory not just for the element currently being added, since that would mean allocating memory(which is computationally expensive) often, instead it grows to be able to hold step more elements. Similarly, if you remove elements in such a way that the array is left holding its capacity, step elements shrink.

The following image illustrates how an Eina_Array grows:

Remarks:: Eina_Array only stores pointers, but it can store data of any type in the form of void pointers.

Functions
Eina_Array *	eina_array_new (unsigned int step)
	Creates a new array.
void	eina_array_free (Eina_Array *array)
	Frees an array.
void	eina_array_step_set (Eina_Array *array, unsigned int sizeof_eina_array, unsigned int step)
	Sets the step of an array.
static void	eina_array_clean (Eina_Array *array)
	Cleans an array.
void	eina_array_flush (Eina_Array *array)
	Flushes an array.
Eina_Bool	eina_array_remove (Eina_Array array, Eina_Bool(keep)(void data, void gdata), void *gdata) 2)
	Rebuilds an array by specifying the data to keep.
static Eina_Bool	eina_array_push (Eina_Array array, const void data) 2)
	Append a data to an array.
static void *	eina_array_pop (Eina_Array *array)
	Remove the last data of an array.
static void *	eina_array_data_get (const Eina_Array *array, unsigned int idx)
	Sets the data at the given position in an array.
static void	eina_array_data_set (const Eina_Array array, unsigned int idx, const void data)
	Sets the data at the given position in an array.
static unsigned int	eina_array_count_get (const Eina_Array *array)
	Return the number of elements in an array.
static unsigned int	eina_array_count (const Eina_Array *array)
	Return the number of elements in an array.
Eina_Iterator *	eina_array_iterator_new (const Eina_Array *array)
	Returns a new iterator associated to an array.
Eina_Accessor *	eina_array_accessor_new (const Eina_Array *array)
	Returns a new accessor associated to an array.
static Eina_Bool	eina_array_foreach (Eina_Array array, Eina_Each_Cb cb, void fdata)
	Provides a safe way to iterate over an array.
Typedefs
typedef struct _Eina_Array	Eina_Array
	The structure type for a generic vector.
typedef void **	Eina_Array_Iterator
	The structure type for an iterator on arrays, used with EINA_ARRAY_ITER_NEXT.
Defines
#define	EINA_ARRAY_ITER_NEXT(array, index, item, iterator)
	Definition of the macro to iterate over an array easily.

Define Documentation

#define EINA_ARRAY_ITER_NEXT	(	array,
		index,
		item,
		iterator
	)

Value:

for (index = 0, iterator = (array)->data;                                 \
       (index < eina_array_count(array)) && ((item = *((iterator)++)));     \
                                                  ++(index))

Definition of the macro to iterate over an array easily.

This macro allows the iteration over array in an easy way. It iterates from the first element to the last one. index is an integer that increases from 0 to the number of elements. item is the data of each element of array, so it is a pointer to a type chosen by the user. iterator is of type Eina_Array_Iterator.

Since :: 2.3.1

Remarks:: This macro can be used for freeing the data of an array, like in the following example:

 Eina_Array         *array;
 char               *item;
 Eina_Array_Iterator iterator;
 unsigned int        i;

 // array is already filled,
 // its elements are just duplicated strings,
 // EINA_ARRAY_ITER_NEXT will be used to free those strings

 EINA_ARRAY_ITER_NEXT(array, i, item, iterator)
   free(item);

Parameters:

array	The array to iterate over
index	The integer number that is increased while iterating
item	The data
iterator	The iterator

Function Documentation

Eina_Accessor* eina_array_accessor_new ( const Eina_Array * array )

Returns a new accessor associated to an array.

This function returns a newly allocated accessor associated to array. If array is NULL or the count member of array is less than or equal to 0, this function returns NULL. If the memory cannot be allocated, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid accessor is returned.

Since :: 2.3.1

Parameters:

[in] array The array

Returns:: A new accessor

static void eina_array_clean ( Eina_Array * array ) [static]

Cleans an array.

This function sets the count member of array to 0. However, it doesn't free any space. This is particularly useful if you need to empty the array and add lots of elements quickly. For performance reasons, there is no check on array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in] array The array to clean

static unsigned int eina_array_count ( const Eina_Array * array ) [static]

Return the number of elements in an array.

This function returns the number of elements in array (array->count). For performance reasons, there is no check of array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in] array The array.

Returns:: The number of elements.

static unsigned int eina_array_count_get ( const Eina_Array * array ) [static]

Return the number of elements in an array.

This function returns the number of elements in array (array->count). For performance reasons, there is no check of array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in] array The array.

Returns:: The number of elements.

Deprecated:: use eina_array_count()

static void* eina_array_data_get	(	const Eina_Array *	array,
		unsigned int	idx
	)		`[static]`

Sets the data at the given position in an array.

This function sets the data at the position idx in array to data, this effectively replaces the previously held data, you must therefore get a pointer to it first if you need to free it. For performance reasons, there is no check on array or idx. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in]	array	The array
[in]	idx	The position of the data to set

static void eina_array_data_set	(	const Eina_Array *	array,
		unsigned int	idx,
		const void *	data
	)		`[static]`

Sets the data at the given position in an array.

This function sets the data at the position idx in array to data, this effectively replaces the previously held data, you must therefore get a pointer to it first if you need to free it. For performance reasons, there is no check on array or idx. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in]	array	The array
[in]	idx	The position of the data to set
[in]	data	The data to set

void eina_array_flush ( Eina_Array * array )

Flushes an array.

This function sets the count and total members of array to 0, frees and sets its data member to NULL. For performance reasons, there is no check on array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Parameters:

[in] array The array to flush

static Eina_Bool eina_array_foreach	(	Eina_Array *	array,
		Eina_Each_Cb	cb,
		void *	fdata
	)		`[static]`

Provides a safe way to iterate over an array.

This function provides a safe way to iterate over an array. cb should return EINA_TRUE as long as you want the function to continue iterating, by returning EINA_FALSE it stops and returns EINA_FALSE as a result.

Since :: 2.3.1

Parameters:

[in]	array	The array to iterate over
[in]	cb	The callback to call for each item
[in]	fdata	The user data to pass to the callback

Returns:: EINA_TRUE if it successfully iterates all the items of the array, otherwise EINA_FALSE

void eina_array_free ( Eina_Array * array )

Frees an array.

This function frees array. It calls first eina_array_flush() then frees the memory of the pointer. It does not free the memory allocated for the elements of array. To free them, use EINA_ARRAY_ITER_NEXT. For performance reasons, there is no check on array.

Since :: 2.3.1

Parameters:

[in] array The array to free

Eina_Iterator* eina_array_iterator_new ( const Eina_Array * array )

Returns a new iterator associated to an array.

This function returns a newly allocated iterator associated to array. If array is NULL or the count member of array is less than or equal to 0, this function returns NULL. If the memory cannot be allocated, NULL is returned and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid iterator is returned.

Since :: 2.3.1

Parameters:

[in] array The array

Returns:: A new iterator

Eina_Array* eina_array_new ( unsigned int step )

Creates a new array.

This function creates a new array. When adding an element, the array allocates step elements. When that buffer is full, adding another element increases the buffer by step elements again.

Since :: 2.3.1

Remarks:: This function returns a valid array on success, or NULL if memory allocation fails. In that case, the error is set to EINA_ERROR_OUT_OF_MEMORY.

Parameters:

[in] step The count of pointers to add when increasing the array size

Returns:: NULL on failure, otherwise a non NULL value

static void* eina_array_pop ( Eina_Array * array ) [static]

Remove the last data of an array.

This function removes the last data of array, decreases the count of array and returns the data. For performance reasons, there is no check of array. If it is NULL or invalid, the program may crash. If the count member is less or equal than 0, NULL is returned.

Since :: 2.3.1

Parameters:

[in] array The array.

Returns:: The retrieved data.

static Eina_Bool eina_array_push	(	Eina_Array *	array,
		const void *	data
	)		`[static]`

Append a data to an array.

This function appends data to array. For performance reasons, there is no check of array. If it is NULL or invalid, the program may crash. If data is NULL, or if an allocation is necessary and fails, EINA_FALSE is returned Otherwise, EINA_TRUE is returned.

Since :: 2.3.1

Parameters:

[in]	array	The array.
[in]	data	The data to add.

Returns:: EINA_TRUE on success, EINA_FALSE otherwise.

Eina_Bool eina_array_remove	(	Eina_Array *	array,
		Eina_Bool()(void data, void *gdata)	keep,
		void *	gdata
	)

Rebuilds an array by specifying the data to keep.

This function rebuilds array by specifying the elements to keep with the function keep. No empty/invalid fields are left in the array. gdata is an additional data to pass to keep. For performance reasons, there is no check on array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Remarks:: If it isn't able to remove items due to an allocation failure, it returns EINA_FALSE and the error is set to EINA_ERROR_OUT_OF_MEMORY.

Parameters:

[in]	array	The array
[in]	keep	The functions that selects the data to keep
[in]	gdata	The data to pass to the function keep

Returns:: EINA_TRUE on success, otherwise EINA_FALSE

void eina_array_step_set	(	Eina_Array *	array,
		unsigned int	sizeof_eina_array,
		unsigned int	step
	)

Sets the step of an array.

This function sets the step of array to step. For performance reasons, there is no check on array. If it is NULL or invalid, the program may crash.

Since :: 2.3.1

Remarks:: This function can only be called on uninitialized arrays.

Parameters:

[in]	array	The array
[in]	sizeof_eina_array	The value returned by sizeof(Eina_Array)
[in]	step	The count of pointers to add when increasing the array size

Functions

Typedefs

Defines

Define Documentation

Function Documentation