These functions provide array management. More...

Data Structures

struct  _Eina_Array
 Type for an array of data. More...
 

Macros

#define EINA_ARRAY_ITER_NEXT(array, index, item, iterator)
 Macro to iterate over an array easily. More...
 

Typedefs

typedef struct _Eina_Array Eina_Array
 Type for a generic vector.
 
typedef void ** Eina_Array_Iterator
 Type for an iterator on arrays, used with EINA_ARRAY_ITER_NEXT.
 

Functions

EAPI Eina_Arrayeina_array_new (unsigned int step) EINA_WARN_UNUSED_RESULT EINA_MALLOC EINA_WARN_UNUSED_RESULT
 Create a new array. More...
 
EAPI void eina_array_free (Eina_Array *array) EINA_ARG_NONNULL(1)
 Free an array. More...
 
EAPI void eina_array_step_set (Eina_Array *array, unsigned int sizeof_eina_array, unsigned int step) EINA_ARG_NONNULL(1)
 Set the step of an array. More...
 
static void eina_array_clean (Eina_Array *array) EINA_ARG_NONNULL(1)
 Clean an array. More...
 
EAPI void eina_array_flush (Eina_Array *array) EINA_ARG_NONNULL(1)
 Flush an array. More...
 
EAPI Eina_Bool eina_array_remove (Eina_Array *array, Eina_Bool(*keep)(void *data, void *gdata), void *gdata) EINA_ARG_NONNULL(1
 Rebuild an array by specifying the data to keep. More...
 
EAPI Eina_Bool static Eina_Bool eina_array_push (Eina_Array *array, const void *data) EINA_ARG_NONNULL(1
 
EAPI Eina_Bool static
Eina_Bool static void * 
eina_array_pop (Eina_Array *array) EINA_ARG_NONNULL(1)
 
static void * eina_array_data_get (const Eina_Array *array, unsigned int idx) EINA_ARG_NONNULL(1)
 
static void eina_array_data_set (const Eina_Array *array, unsigned int idx, const void *data) EINA_ARG_NONNULL(1)
 Set the data at a given position in an array. More...
 
static unsigned int eina_array_count_get (const Eina_Array *array) EINA_ARG_NONNULL(1) EINA_WARN_UNUSED_RESULT
 
static unsigned int eina_array_count (const Eina_Array *array) EINA_ARG_NONNULL(1) EINA_WARN_UNUSED_RESULT
 
EAPI Eina_Iteratoreina_array_iterator_new (const Eina_Array *array) EINA_MALLOC EINA_ARG_NONNULL(1) EINA_WARN_UNUSED_RESULT
 Returned a new iterator associated to an array. More...
 
EAPI Eina_Accessoreina_array_accessor_new (const Eina_Array *array) EINA_MALLOC EINA_ARG_NONNULL(1) EINA_WARN_UNUSED_RESULT
 Returned a new accessor associated to an array. More...
 
static Eina_Bool eina_array_foreach (Eina_Array *array, Eina_Each_Cb cb, void *fdata)
 Provide a safe way to iterate over an array. More...
 

Detailed Description

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 place, 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 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.

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.

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 that the array is left holding its capacity - step elements it will shrink.

The following image illustrates how an Eina_Array grows:

eina_array-growth.png

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

See here some examples:

Macro Definition 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))

Macro to iterate over an array easily.

Parameters
arrayThe array to iterate over.
indexThe integer number that is increased while itareting.
itemThe data
iteratorThe 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;
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.

Referenced by eina_benchmark_free(), eina_module_find(), eina_module_list_free(), eina_module_list_load(), and eina_module_list_unload().

Function Documentation

EAPI Eina_Array* eina_array_new ( unsigned int  step)

Create a new array.

Parameters
stepThe 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. In that case, the error is set to EINA_ERROR_OUT_OF_MEMORY.

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

References _Eina_Array::count, _Eina_Array::data, EINA_ERROR_OUT_OF_MEMORY, eina_error_set(), EINA_MAGIC_SET, _Eina_Array::step, _Eina_Array::total, and _Eina_Array::version.

Referenced by eina_benchmark_run(), eina_file_split(), eina_module_arch_list_get(), and eina_module_list_get().

EAPI void eina_array_free ( Eina_Array array)

Free an array.

Parameters
arrayThe 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, use EINA_ARRAY_ITER_NEXT. For performance reasons, there is no check of array.

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

References eina_array_flush().

Referenced by eina_benchmark_free().

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

Set the step of an array.

Parameters
arrayThe array.
sizeof_eina_arrayShould be the value returned by sizeof(Eina_Array).
stepThe 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.
Examples:
eina_array_01.c.

References _Eina_Array::count, _Eina_Array::data, EINA_MAGIC_SET, _Eina_Array::step, _Eina_Array::total, and _Eina_Array::version.

static void eina_array_clean ( Eina_Array array)
inlinestatic

Clean an array.

Parameters
arrayThe 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.

References _Eina_Array::count, and _Eina_Array::version.

EAPI void eina_array_flush ( Eina_Array array)

Flush an array.

Parameters
arrayThe 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.

References _Eina_Array::count, _Eina_Array::data, and _Eina_Array::total.

Referenced by eina_array_free(), and eina_module_list_free().

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

Rebuild an array by specifying the data to keep.

Parameters
arrayThe array.
keepThe functions which selects the data to keep.
gdataThe data to pass to the function keep.
Returns
EINA_TRUE on success, EINA_FALSE oterwise.

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 and the error is set to EINA_ERROR_OUT_OF_MEMORY.

Examples:
eina_array_02.c.
static void eina_array_data_set ( const Eina_Array array,
unsigned int  idx,
const void *  data 
)
inlinestatic

Set the data at a given position in an array.

Parameters
arrayThe array.
idxThe potition of the data to set.
dataThe 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.
EAPI Eina_Iterator* eina_array_iterator_new ( const Eina_Array array)

Returned a new iterator associated to an array.

Parameters
arrayThe 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 and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid iterator is returned.

Examples:
eina_iterator_01.c.

References EINA_ERROR_OUT_OF_MEMORY, eina_error_set(), EINA_MAGIC_SET, FUNC_ITERATOR_FREE, FUNC_ITERATOR_GET_CONTAINER, FUNC_ITERATOR_NEXT, and _Eina_Array::version.

EAPI Eina_Accessor* eina_array_accessor_new ( const Eina_Array array)

Returned a new accessor associated to an array.

Parameters
arrayThe 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 and EINA_ERROR_OUT_OF_MEMORY is set. Otherwise, a valid accessor is returned.

Examples:
eina_accessor_01.c.

References EINA_ERROR_OUT_OF_MEMORY, eina_error_set(), EINA_MAGIC_SET, FUNC_ACCESSOR_FREE, FUNC_ACCESSOR_GET_AT, FUNC_ACCESSOR_GET_CONTAINER, and _Eina_Array::version.

static Eina_Bool eina_array_foreach ( Eina_Array array,
Eina_Each_Cb  cb,
void *  fdata 
)
inlinestatic

Provide a safe way to iterate over an array.

Parameters
arrayThe array to iterate over.
cbThe callback to call for each item.
fdataThe user data to pass to the callback.
Returns
EINA_TRUE if it successfully iterate all items of the array.

This function provide 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 will stop and return EINA_FALSE as a result.

Examples:
eina_array_01.c, and eina_simple_xml_parser_01.c.