Bluetooth: Host: Add function to retreive per_adv_sync obj from index.

Gives the application a two way mapping between array index
and a per_adv_sync object instead of current only per_adv_sync
obj -> index using bt_le_per_adv_sync_get_index.

Signed-off-by: Jakob Krantz <[email protected]>

Author: jakkra

include/zephyr/bluetooth/bluetooth.h

@@ -1417,6 +1417,20 @@ struct bt_le_per_adv_sync_param {
  */
 uint8_t bt_le_per_adv_sync_get_index(struct bt_le_per_adv_sync *per_adv_sync);
 
+/**
+ * @brief Get a periodic advertising sync object from the array index.
+ *
+ * This function is to get the periodic advertising sync object from
+ * the array index.
+ * The array has CONFIG_BT_PER_ADV_SYNC_MAX elements.
+ *
+ * @param index The index of the periodic advertising sync object.
+ *              The range of the index value is 0..CONFIG_BT_PER_ADV_SYNC_MAX-1
+ *
+ * @return The periodic advertising sync object of the array index or NULL if invalid index.
+ */
+struct bt_le_per_adv_sync *bt_le_per_adv_sync_lookup_index(uint8_t index);
+
 /** @brief Advertising set info structure. */
 struct bt_le_per_adv_sync_info {
 	/** Periodic Advertiser Address */

subsys/bluetooth/host/scan.c

@@ -1345,6 +1345,15 @@ uint8_t bt_le_per_adv_sync_get_index(struct bt_le_per_adv_sync *per_adv_sync)
 	return (uint8_t)index;
 }
 
+struct bt_le_per_adv_sync *bt_le_per_adv_sync_lookup_index(uint8_t index)
+{
+	if (index >= ARRAY_SIZE(per_adv_sync_pool)) {
+		return NULL;
+	}
+
+	return &per_adv_sync_pool[index];
+}
+
 int bt_le_per_adv_sync_get_info(struct bt_le_per_adv_sync *per_adv_sync,
 				struct bt_le_per_adv_sync_info *info)
 {