Eina_Iterator usage

As always when using eina we need to include it:

#include <stdio.h>
#include <Eina.h>

Here we a declare an unimpressive function that prints some data:

static Eina_Bool
print_one(const void *container EINA_UNUSED, void *data, void *fdata EINA_UNUSED)
{
printf("%s\n", (char*)data);
return EINA_TRUE;
}
Note
Returning EINA_TRUE is important so we don't stop iterating over the container.

And here's a more interesting function, it uses an iterator to print the contents of a container. What's interesting about it is that it doesn't care the type of container, it works for anything that can provide an iterator:

static void
print_eina_container(Eina_Iterator *it)
{
eina_iterator_foreach(it, print_one, NULL);
printf("\n");
}

And on to our main function were we declare some variables and initialize eina, nothing too special:

int
main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
{
const char *strings[] = {
"unintersting string", "husker", "starbuck", "husker"
};
const char *more_strings[] = {
"very unintersting string",
"what do your hear?",
"nothing but the rain",
"then grab your gun and bring the cat in"
};
Eina_Array *array;
Eina_List *list = NULL;
unsigned short int i;
char *uninteresting;

Next we populate both an array and a list with our strings, for more details see Adding elements to Eina_List and Basic array usage :

array = eina_array_new(4);
for (i = 0; i < 4; i++)
{
eina_array_push(array, strings[i]);
list = eina_list_append(list, more_strings[i]);
}

And now we create an array and because the first element of the container doesn't interest us we skip it:

if (!eina_iterator_next(it, (void **)&uninteresting))

Having our iterator now pointing to interesting data we go ahead and print:

return -1;
print_eina_container(it);

As always once data with a structure we free it, but just because we can we do it by asking the iterator for it's container, and then of course free the iterator itself:

But so far you're not impressed in Basic array usage an array is also printed, so now we go to the cool stuff and use an iterator to do same stuff to a list:

if (!eina_iterator_next(it, (void **)&uninteresting))
return -1;
print_eina_container(it);
Note
The only significant difference to the block above is in the function used to create the iterator.

And now we free the list and shut eina down:

return 0;
}
_Eina_Iterator
Definition: eina_iterator.h:158
eina_list_iterator_new
EAPI Eina_Iterator * eina_list_iterator_new(const Eina_List *list)
Returns a new iterator associated with a list.
Definition: eina_list.c:1574
eina_iterator_next
Eina_Bool eina_iterator_next(Eina_Iterator *iterator, void **data)
Returns the value of the current element and go to the next one.
Definition: eina_iterator.c:118
eina_list_append
EAPI Eina_List * eina_list_append(Eina_List *list, const void *data)
Appends the given data to the given linked list.
Definition: eina_list.c:584
EINA_UNUSED
#define EINA_UNUSED
Definition: eina_types.h:339
Eina.h
Eina Utility library.
eina_iterator_foreach
void eina_iterator_foreach(Eina_Iterator *iterator, Eina_Each_Cb cb, const void *fdata)
Iterates over the container and execute a callback on each element.
Definition: eina_iterator.c:130
eina_init
int eina_init(void)
Initializes the Eina library.
Definition: eina_main.c:279
_Eina_Array
Definition: eina_array.h:228
eina_array_free
EAPI void eina_array_free(Eina_Array *array)
Frees an array.
Definition: eina_array.c:295
eina_array_push
EAPI Eina_Bool static Eina_Bool eina_array_push(Eina_Array *array, const void *data) EINA_ARG_NONNULL(1
Appends a data item to an array.
eina_array_iterator_new
EAPI Eina_Iterator * eina_array_iterator_new(const Eina_Array *array)
Gets a new iterator associated with an array.
Definition: eina_array.c:394
eina_shutdown
int eina_shutdown(void)
Shuts down the Eina library.
Definition: eina_main.c:350
EINA_TRUE
#define EINA_TRUE
Definition: eina_types.h:539
eina_array_new
EAPI Eina_Array * eina_array_new(unsigned int step)
Creates a new array.
Definition: eina_array.c:276
eina_list_free
EAPI Eina_List * eina_list_free(Eina_List *list)
Frees an entire list and all the nodes, ignoring the data contained.
Definition: eina_list.c:823
eina_iterator_container_get
void * eina_iterator_container_get(Eina_Iterator *iterator)
Returns the container of an iterator.
Definition: eina_iterator.c:109
Eina_Bool
unsigned char Eina_Bool
Definition: eina_types.h:527
eina_iterator_free
void eina_iterator_free(Eina_Iterator *iterator)
Frees an iterator.
Definition: eina_iterator.c:98
_Eina_List
Definition: eina_list.h:317