These functions 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 position, the Eina List is the correct container to use.

To use the array data type, eina_init() must be called before any other array functions. When no more eina array functions are used, eina_shutdown() must be called to free all the resources.

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 frees the memory used by the Eina_Array itself, but does not free any memory used to store the data of each element. To free that memory you must iterate over the array and free each data element individually. A convenient way to do that is by using EINA_ARRAY_ITER_NEXT. An example of that pattern is given in the description of EINA_ARRAY_ITER_NEXT.

Warning:: 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 that when you remove an element from an array it may shrink.

Allocating memory is expensive, so when the array needs to grow it allocates enough memory to hold step additional elements, not just the element currently being added. Similarly if you remove elements, it won't free space until you have removed step elements.

The following image illustrates how an Eina_Array grows:

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

See here some examples:

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)
	Appends a data to an array.
static void *	eina_array_pop (Eina_Array *array)
	Removes the last data of an array.
static void *	eina_array_data_get (const Eina_Array *array, unsigned int idx)
	Returns the data at a 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 a given position in an array.
static unsigned int	eina_array_count_get (const Eina_Array *array)
	Returns the number of elements in an array.
static unsigned int	eina_array_count (const Eina_Array *array)
	Returns the number of elements in an array.
Eina_Iterator *	eina_array_iterator_new (const Eina_Array *array)
	Gets a new iterator associated to an array.
Eina_Accessor *	eina_array_accessor_new (const Eina_Array *array)
	Gets 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
typedef void **	Eina_Array_Iterator
Defines
#define	EINA_ARRAY_ITER_NEXT(array, index, item, iterator)
	Definition for 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 for the macro to iterate over an array easily.

Parameters:

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

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.

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);

Examples:: eina_array_02.c.

Typedef Documentation

Eina_Array

Type for a generic vector.

Eina_Array_Iterator

Type for an iterator on arrays, used with EINA_ARRAY_ITER_NEXT.

Function Documentation

Eina_Accessor* eina_array_accessor_new ( const Eina_Array * array )

Gets a new accessor associated to an array.

Parameters:

array The array.

Returns:: A new accessor.

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

Since :: 2.3.1

Examples:: eina_accessor_01.c.

static void eina_array_clean ( Eina_Array * array ) [static]

Cleans an array.

Parameters:

array The array to clean.

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 of array. If it is NULL or invalid, the program may crash.

Examples:: eina_array_02.c.

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

Returns the number of elements in an array.

Parameters:

array The array.

Returns:: The number of elements.

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.

Examples:: eina_array_01.c.

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

Returns the number of elements in an array.

Deprecated:: use eina_array_count()

Parameters:

array The array.

Returns:: The number of elements.

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.

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

Returns the data at a given position in an array.

Parameters:

array	The array.
idx	The position of the data to retrieve.

Returns:: The retrieved data.

This function returns the data at the position idx in array. For performance reasons, there is no check of array or idx. If it is NULL or invalid, the program may crash.

Examples:: eina_array_01.c.

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

Sets the data at a given position in an array.

Parameters:

array	The array.
idx	The position of the data to set.
data	The data to set.

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 of array or idx. If it is NULL or invalid, the program may crash.

Examples:: eina_array_02.c.

void eina_array_flush ( Eina_Array * array )

Flushes an array.

Parameters:

array The array to flush.

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

Since :: 2.3.1

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.

Parameters:

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

Returns:: EINA_TRUE if it successfully iterate all items of the 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. If cb returns EINA_FALSE, iterations will stop and the function will also return EINA_FALSE.

Examples:: eina_array_01.c, and eina_simple_xml_parser_01.c.

void eina_array_free ( Eina_Array * array )

Frees an array.

Parameters:

array The array to free.

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

Since :: 2.3.1

Examples:: eina_accessor_01.c, eina_array_01.c, eina_array_02.c, eina_iterator_01.c, and eina_simple_xml_parser_01.c.

Eina_Iterator* eina_array_iterator_new ( const Eina_Array * array )

Gets a new iterator associated to an array.

Parameters:

array The array.

Returns:: A new iterator.

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

Since :: 2.3.1

Examples:: eina_iterator_01.c.

Eina_Array* eina_array_new ( unsigned int step )

Creates a new array.

Parameters:

step	The count of pointers to add when increasing the array size.

Returns:: NULL on failure, non NULL otherwise.

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

This function return a valid array on success, or NULL if memory allocation fails.

Since :: 2.3.1

Examples:: eina_accessor_01.c, eina_array_01.c, eina_array_02.c, eina_iterator_01.c, and eina_simple_xml_parser_01.c.

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

Removes the last data of an array.

Parameters:

array The array.

Returns:: The retrieved data.

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.

Examples:: eina_array_01.c.

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

Appends a data to an array.

Parameters:

array	The array.
data	The data to add.

Returns:: EINA_TRUE on success, EINA_FALSE otherwise.

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.

Examples:: eina_accessor_01.c, eina_array_01.c, eina_array_02.c, eina_iterator_01.c, and eina_simple_xml_parser_01.c.

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.

Parameters:

array	The array.
keep	The functions which selects the data to keep.
gdata	The data to pass to the function keep.

Returns:: EINA_TRUE on success, EINA_FALSE otherwise.

This function rebuilds array be 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 of array. If it is NULL or invalid, the program may crash.

If it wasn't able to remove items due to an allocation failure, it will return EINA_FALSE.

Since :: 2.3.1

Examples:: eina_array_02.c.

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

Sets the step of an array.

Parameters:

array	The array.
sizeof_eina_array	Should be the value returned by sizeof(Eina_Array).
step	The count of pointers to add when increasing the array size.

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

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

Since :: 2.3.1

Examples:: eina_array_01.c.

Functions

Typedefs

Defines

Define Documentation

Typedef Documentation

Function Documentation