app_fifo.h

00001 /* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved.
00002  *
00003  * The information contained herein is property of Nordic Semiconductor ASA.
00004  * Terms and conditions of usage are described in detail in NORDIC
00005  * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
00006  *
00007  * Licensees are granted free, non-transferable use of the information. NO
00008  * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
00009  * the file.
00010  *
00011  */
00012 
00013 /**@file
00014  *
00015  * @defgroup app_fifo FIFO implementation
00016  * @{
00017  * @ingroup app_common
00018  *
00019  * @brief FIFO implementation.
00020  */
00021 
00022 #ifndef APP_FIFO_H__
00023 #define APP_FIFO_H__
00024 
00025 #include <stdint.h>
00026 #include <stdlib.h>
00027 #include "nrf_error.h"
00028 
00029 /**@brief A FIFO instance structure. Keeps track of which bytes to read and write next.
00030  *        Also it keeps the information about which memory is allocated for the buffer
00031  *        and its size. This needs to be initialized by app_fifo_init() before use.
00032  */
00033 typedef struct
00034 {
00035     uint8_t *          p_buf;           /**< Pointer to FIFO buffer memory.                      */
00036     uint16_t           buf_size_mask;   /**< Read/write index mask. Also used for size checking. */
00037     volatile uint32_t  read_pos;        /**< Next read position in the FIFO buffer.              */
00038     volatile uint32_t  write_pos;       /**< Next write position in the FIFO buffer.             */
00039 } app_fifo_t;
00040 
00041 /**@brief Function for initializing the FIFO.
00042  *
00043  * @param[out] p_fifo   FIFO object.
00044  * @param[in]  p_buf    FIFO buffer for storing data. The buffer size has to be a power of two.
00045  * @param[in]  buf_size Size of the FIFO buffer provided, has to be a power of 2.
00046  *
00047  * @retval     NRF_SUCCESS              If initialization was successful.
00048  * @retval     NRF_ERROR_NULL           If a NULL pointer is provided as buffer.
00049  * @retval     NRF_ERROR_INVALID_LENGTH If size of buffer provided is not a power of two.
00050  */
00051 uint32_t app_fifo_init(app_fifo_t * p_fifo, uint8_t * p_buf, uint16_t buf_size);
00052 
00053 /**@brief Function for adding an element to the FIFO.
00054  *
00055  * @param[in]  p_fifo   Pointer to the FIFO.
00056  * @param[in]  byte     Data byte to add to the FIFO.
00057  *
00058  * @retval     NRF_SUCCESS              If an element has been successfully added to the FIFO.
00059  * @retval     NRF_ERROR_NO_MEM         If the FIFO is full.
00060  */
00061 uint32_t app_fifo_put(app_fifo_t * p_fifo, uint8_t byte);
00062 
00063 /**@brief Function for getting the next element from the FIFO.
00064  *
00065  * @param[in]  p_fifo   Pointer to the FIFO.
00066  * @param[out] p_byte   Byte fetched from the FIFO.
00067  *
00068  * @retval     NRF_SUCCESS              If an element was returned.
00069  * @retval     NRF_ERROR_NOT_FOUND      If there is no more elements in the queue.
00070  */
00071 uint32_t app_fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte);
00072 
00073 /**@brief Function for flushing the FIFO.
00074  *
00075  * @param[in]  p_fifo   Pointer to the FIFO.
00076  *
00077  * @retval     NRF_SUCCESS              If the FIFO flushed successfully.
00078  */
00079 uint32_t app_fifo_flush(app_fifo_t * p_fifo);
00080 
00081 #endif // APP_FIFO_H__
00082 
00083 /** @} */