text: /**
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   * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
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   * 4. This software, with or without modification, must only be used with a
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  /** @file coap_queue.h
   *
   * @defgroup iot_sdk_coap_queue CoAP Message Queue
   * @ingroup iot_sdk_coap
   * @{
   * @brief TODO.
   */
  
  #ifndef COAP_QUEUE_H__
  #define COAP_QUEUE_H__
  
  #include <stdint.h>
  
  #include "coap_transport.h"
  #include "coap_message.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  typedef struct
  {
      void *                   p_arg;                 /**< Miscellaneous pointer to application provided data that is associated with the message. Copied from the coap_message_t when creating the item. */
      uint32_t                 handle;                /**< Quick reference to the handle value of the current item. */
      uint16_t                 mid;                   /**< Message ID. */
      uint8_t                  token_len;             /**< Message Token length. */
      uint8_t                  token[8];              /**< Message Token value up to 8 bytes. */
      uint8_t                  retrans_count;         /**< Re-transmission attempt count. */
      uint16_t                 timeout;               /**< Time until new re-transmission attempt. */
      uint16_t                 timeout_val;           /**< Last timeout value used. */
      coap_port_t              port;                  /**< Source port to use when re-transmitting. */
      uint8_t *                p_buffer;              /**< Pointer to the data buffer containing the encoded CoAP message. */
      uint32_t                 buffer_len;            /**< Size of the data buffer containing the encoded CoAP message. */
      coap_remote_t            remote;                /**< Destination address and port number to the remote. */
      coap_response_callback_t callback;              /**< Callback function to be called upon response or transmission timeout. */
  } coap_queue_item_t;
  
  /**@brief Initilize the CoAP message queue.
   *
   * @retval NRF_SUCCESS If initialization completed successfully.
   */
  uint32_t coap_queue_init(void);
  
  /**@brief Add item to the queue.
   *
   * @param[in] p_item      Pointer to an item which to add to the queue. The function will copy all
   *                        data provided.
   *
   * @retval NRF_SUCCESS         If adding the item was successful.
   * @retval NRF_ERROR_NO_MEM    If max number of queued elements has been reached. This is
   *                             configured by COAP_MESSAGE_QUEUE_SIZE in sdk_config.h.
   * @retval NRF_ERROR_DATA_SIZE If the element could not be added.
   */
  uint32_t coap_queue_add(coap_queue_item_t * p_item);
  
  /**@brief Remove item from the queue.
   *
   * @param[in] p_item      Pointer to an item which to remove from the queue. Should not be NULL.
   *
   * @retval NRF_SUCCESS         If the item was successfully removed from the queue.
   * @retval NRF_ERROR_NULL      If p_item pointer is NULL.
   * @retval NRF_ERROR_NOT_FOUND If the item was not located in the queue.
   */
  uint32_t coap_queue_remove(coap_queue_item_t * p_item);
  
  /**@brief Search for item by token.
   *
   * @details Search the items for any item matching the token.
   *
   * @param[out] pp_item    Pointer to be filled by the function if item matching the token
   *                        has been found. Should not be NULL.
   * @param[in]  p_token    Pointer to token array to be matched.
   * @param[in]  token_len  Length of the token to be matched.
   *
   * @retval NRF_SUCCESS         If an item was successfully located.
   * @retval NRF_ERROR_NULL      If pp_item pointer is NULL.
   * @retval NRF_ERROR_NOT_FOUND If no item was found.
   */
  uint32_t coap_queue_item_by_token_get(coap_queue_item_t ** pp_item, uint8_t * p_token, uint8_t token_len);
  
  /**@brief Search for item by message id.
   *
   * @details Search the items for any item matching the message id.
   *
   * @param[out] pp_item    Pointer to be filled by the funciton if item matching the message id
   *                        has been found. Should not be NULL.
   * @param[in]  message_id Message id to be matched.
   *
   * @retval NRF_SUCCESS If an item was successfully located.
   * @retval NRF_ERROR_NULL      If pp_item pointer is NULL.
   * @retval NRF_ERROR_NOT_FOUND If no item was found.
   */
  uint32_t coap_queue_item_by_mid_get(coap_queue_item_t ** pp_item, uint16_t message_id);
  
  /**@brief Iterate through items.
   *
   * @param[out] pp_item    Pointer to be filled by the search function upon finding the next
   *                        queued item starting from the p_item pointer provided. Should
   *                        not be NULL.
   * @param[in]  p_item     Pointer to the item where to start the search.
   *
   * @retval NRF_SUCCESS         If item was found.
   * @retval NRF_ERROR_NULL      If pp_item pointer is NULL.
   * @retval NRF_ERROR_NOT_FOUND If next item was not found.
   */
  uint32_t coap_queue_item_next_get(coap_queue_item_t ** pp_item, coap_queue_item_t * p_item);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif // COAP_QUEUE_H__
  
  /** @} */
  