146 lines
6.9 KiB
C
146 lines
6.9 KiB
C
/* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved.
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*
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* The information contained herein is property of Nordic Semiconductor ASA.
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* Terms and conditions of usage are described in detail in NORDIC
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* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
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*
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* Licensees are granted free, non-transferable use of the information. NO
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* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
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* the file.
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*
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*/
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/**@file
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*
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* @defgroup app_fifo FIFO implementation
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* @{
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* @ingroup app_common
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*
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* @brief FIFO implementation.
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*/
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#ifndef APP_FIFO_H__
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#define APP_FIFO_H__
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#include <stdint.h>
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#include <stdlib.h>
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/**@brief A FIFO instance structure.
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* @details Keeps track of which bytes to read and write next.
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* Also, it keeps the information about which memory is allocated for the buffer
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* and its size. This structure must be initialized by app_fifo_init() before use.
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*/
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typedef struct
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{
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uint8_t * p_buf; /**< Pointer to FIFO buffer memory. */
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uint16_t buf_size_mask; /**< Read/write index mask. Also used for size checking. */
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volatile uint32_t read_pos; /**< Next read position in the FIFO buffer. */
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volatile uint32_t write_pos; /**< Next write position in the FIFO buffer. */
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} app_fifo_t;
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/**@brief Function for initializing the FIFO.
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*
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* @param[out] p_fifo FIFO object.
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* @param[in] p_buf FIFO buffer for storing data. The buffer size must be a power of two.
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* @param[in] buf_size Size of the FIFO buffer provided. This size must be a power of two.
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*
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* @retval NRF_SUCCESS If initialization was successful.
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* @retval NRF_ERROR_NULL If a NULL pointer is provided as buffer.
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* @retval NRF_ERROR_INVALID_LENGTH If size of buffer provided is not a power of two.
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*/
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uint32_t app_fifo_init(app_fifo_t * p_fifo, uint8_t * p_buf, uint16_t buf_size);
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/**@brief Function for adding an element to the FIFO.
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*
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* @param[in] p_fifo Pointer to the FIFO.
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* @param[in] byte Data byte to add to the FIFO.
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*
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* @retval NRF_SUCCESS If an element has been successfully added to the FIFO.
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* @retval NRF_ERROR_NO_MEM If the FIFO is full.
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*/
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uint32_t app_fifo_put(app_fifo_t * p_fifo, uint8_t byte);
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/**@brief Function for getting the next element from the FIFO.
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*
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* @param[in] p_fifo Pointer to the FIFO.
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* @param[out] p_byte Byte fetched from the FIFO.
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*
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* @retval NRF_SUCCESS If an element was returned.
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* @retval NRF_ERROR_NOT_FOUND If there are no more elements in the queue.
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*/
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uint32_t app_fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte);
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/**@brief Function for looking at an element in the FIFO, without consuming it.
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*
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* @param[in] p_fifo Pointer to the FIFO.
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* @param[in] index Which element to look at. The lower the index, the earlier it was put.
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* @param[out] p_byte Byte fetched from the FIFO.
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*
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* @retval NRF_SUCCESS If an element was returned.
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* @retval NRF_ERROR_NOT_FOUND If there are no more elements in the queue, or the index was
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* too large.
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*/
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uint32_t app_fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte);
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/**@brief Function for flushing the FIFO.
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*
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* @param[in] p_fifo Pointer to the FIFO.
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*
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* @retval NRF_SUCCESS If the FIFO was flushed successfully.
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*/
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uint32_t app_fifo_flush(app_fifo_t * p_fifo);
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/**@brief Function for reading bytes from the FIFO.
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*
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* This function can also be used to get the number of bytes in the FIFO.
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*
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* @param[in] p_fifo Pointer to the FIFO. Must not be NULL.
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* @param[out] p_byte_array Memory pointer where the read bytes are fetched from the FIFO.
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* Can be NULL. If NULL, the number of bytes that can be read in the FIFO
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* are returned in the p_size parameter.
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* @param[inout] p_size Address to memory indicating the maximum number of bytes to be read.
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* The provided memory is overwritten with the actual number of bytes
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* read if the procedure was successful. This field must not be NULL.
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* If p_byte_array is set to NULL by the application, this parameter
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* returns the number of bytes in the FIFO.
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*
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* @retval NRF_SUCCESS If the procedure is successful. The actual number of bytes read might
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* be less than the requested maximum, depending on how many elements exist
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* in the FIFO. Even if less bytes are returned, the procedure is considered
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* successful.
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* @retval NRF_ERROR_NULL If a NULL parameter was passed for a parameter that must not
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* be NULL.
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* @retval NRF_ERROR_NOT_FOUND If the FIFO is empty.
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*/
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uint32_t app_fifo_read(app_fifo_t * p_fifo, uint8_t * p_byte_array, uint32_t * p_size);
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/**@brief Function for writing bytes to the FIFO.
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*
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* This function can also be used to get the available size on the FIFO.
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*
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* @param[in] p_fifo Pointer to the FIFO. Must not be NULL.
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* @param[in] p_byte_array Memory pointer containing the bytes to be written to the FIFO.
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* Can be NULL. If NULL, this function returns the number of bytes
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* that can be written to the FIFO.
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* @param[inout] p_size Address to memory indicating the maximum number of bytes to be written.
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* The provided memory is overwritten with the number of bytes that were actually
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* written if the procedure is successful. This field must not be NULL.
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* If p_byte_array is set to NULL by the application, this parameter
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* returns the number of bytes available in the FIFO.
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*
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* @retval NRF_SUCCESS If the procedure is successful. The actual number of bytes written might
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* be less than the requested maximum, depending on how much room there is in
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* the FIFO. Even if less bytes are written, the procedure is considered
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* successful. If the write was partial, the application should use
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* subsequent calls to attempt writing the data again.
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* @retval NRF_ERROR_NULL If a NULL parameter was passed for a parameter that must not
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* be NULL.
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* @retval NRF_ERROR_NO_MEM If the FIFO is full.
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*
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*/
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uint32_t app_fifo_write(app_fifo_t * p_fifo, uint8_t const * p_byte_array, uint32_t * p_size);
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#endif // APP_FIFO_H__
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/** @} */
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