Sorted list library

The sorted list library provides an implementation of the ordered list. Access to the list is not protected. The user function is used for comparing items.

Creating a list

To create a sorted list instance, use the NRF_SORTLIST_DEF macro and provide the identifier and the compare function.

Using the list

Items which can be put into the list must contain the nrf_sortlist_item_t element. CONTAINER_OF() macro should be used to ensure that the nrf_sortlist_item_t element is correctly used.

Sample code for element structure definition:

typedef struct {
 uint32_t x;
 nrf_sortlist_item_t item;
} item_t;

Example of the compare function:

bool compare_function(nrf_sortlist_item_t * p_item0, nrf_sortlist_item_t * p_item1)
{
 item_t * p_item0 = CONTAINER_OF(p_item0, item_t, item);
 item_t * p_item1 = CONTAINER_OF(p_item1, item_t, item);

 return (p_item0->x > p_item1->x) ? true : false;
}

Example of sorted list instance definition:

NRF_SORTLIST_DEF(example_list, compare_function);

Example of adding and poping an element into/from the list:

item_t item0, item1;
item0.x = 100;
item1.x = 110;

nrf_sortlist_add(&example_list, &item0.item);
nrf_sortlist_add(&example_list, &item1.item);

item_t * p_item;
p_item = CONTAINER_OF(nrf_sortlist_pop(&example_list), item_t, item);

// p_item points to item1 even though it was later added to the list.
// This happens because the compare function evaluated the elements and reordered them.