这个fifo是nordic的源码
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.h文件
/**
* Copyright (c) 2013 - 2017, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/**@file
*
* @defgroup app_fifo FIFO implementation
* @{
* @ingroup app_common
*
* @brief FIFO implementation.
*/
#ifndef APP_FIFO_H__
#define APP_FIFO_H__
#include
#include
#ifdef __cplusplus
extern "C" {
#endif
/**@brief A FIFO instance structure.
* @details Keeps track of which bytes to read and write next.
* Also, it keeps the information about which memory is allocated for the buffer
* and its size. This structure must be initialized by app_fifo_init() before use.
*/
typedef struct
{
uint8_t * p_buf; /**< Pointer to FIFO buffer memory. */
uint16_t buf_size_mask; /**< Read/write index mask. Also used for size checking. */
volatile uint32_t read_pos; /**< Next read position in the FIFO buffer. */
volatile uint32_t write_pos; /**< Next write position in the FIFO buffer. */
} app_fifo_t;
/**@brief Function for initializing the FIFO.
*
* @param[out] p_fifo FIFO object.
* @param[in] p_buf FIFO buffer for storing data. The buffer size must be a power of two.
* @param[in] buf_size Size of the FIFO buffer provided. This size must be a power of two.
*
* @retval NRF_SUCCESS If initialization was successful.
* @retval NRF_ERROR_NULL If a NULL pointer is provided as buffer.
* @retval NRF_ERROR_INVALID_LENGTH If size of buffer provided is not a power of two.
*/
uint32_t app_fifo_init(app_fifo_t * p_fifo, uint8_t * p_buf, uint16_t buf_size);
/**@brief Function for adding an element to the FIFO.
*
* @param[in] p_fifo Pointer to the FIFO.
* @param[in] byte Data byte to add to the FIFO.
*
* @retval NRF_SUCCESS If an element has been successfully added to the FIFO.
* @retval NRF_ERROR_NO_MEM If the FIFO is full.
*/
uint32_t app_fifo_put(app_fifo_t * p_fifo, uint8_t byte);
/**@brief Function for getting the next element from the FIFO.
*
* @param[in] p_fifo Pointer to the FIFO.
* @param[out] p_byte Byte fetched from the FIFO.
*
* @retval NRF_SUCCESS If an element was returned.
* @retval NRF_ERROR_NOT_FOUND If there are no more elements in the queue.
*/
uint32_t app_fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte);
/**@brief Function for looking at an element in the FIFO, without consuming it.
*
* @param[in] p_fifo Pointer to the FIFO.
* @param[in] index Which element to look at. The lower the index, the earlier it was put.
* @param[out] p_byte Byte fetched from the FIFO.
*
* @retval NRF_SUCCESS If an element was returned.
* @retval NRF_ERROR_NOT_FOUND If there are no more elements in the queue, or the index was
* too large.
*/
uint32_t app_fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte);
/**@brief Function for flushing the FIFO.
*
* @param[in] p_fifo Pointer to the FIFO.
*
* @retval NRF_SUCCESS If the FIFO was flushed successfully.
*/
uint32_t app_fifo_flush(app_fifo_t * p_fifo);
/**@brief Function for reading bytes from the FIFO.
*
* This function can also be used to get the number of bytes in the FIFO.
*
* @param[in] p_fifo Pointer to the FIFO. Must not be NULL.
* @param[out] p_byte_array Memory pointer where the read bytes are fetched from the FIFO.
* Can be NULL. If NULL, the number of bytes that can be read in the FIFO
* are returned in the p_size parameter.
* @param[inout] p_size Address to memory indicating the maximum number of bytes to be read.
* The provided memory is overwritten with the actual number of bytes
* read if the procedure was successful. This field must not be NULL.
* If p_byte_array is set to NULL by the application, this parameter
* returns the number of bytes in the FIFO.
*
* @retval NRF_SUCCESS If the procedure is successful. The actual number of bytes read might
* be less than the requested maximum, depending on how many elements exist
* in the FIFO. Even if less bytes are returned, the procedure is considered
* successful.
* @retval NRF_ERROR_NULL If a NULL parameter was passed for a parameter that must not
* be NULL.
* @retval NRF_ERROR_NOT_FOUND If the FIFO is empty.
*/
uint32_t app_fifo_read(app_fifo_t * p_fifo, uint8_t * p_byte_array, uint32_t * p_size);
/**@brief Function for writing bytes to the FIFO.
*
* This function can also be used to get the available size on the FIFO.
*
* @param[in] p_fifo Pointer to the FIFO. Must not be NULL.
* @param[in] p_byte_array Memory pointer containing the bytes to be written to the FIFO.
* Can be NULL. If NULL, this function returns the number of bytes
* that can be written to the FIFO.
* @param[inout] p_size Address to memory indicating the maximum number of bytes to be written.
* The provided memory is overwritten with the number of bytes that were actually
* written if the procedure is successful. This field must not be NULL.
* If p_byte_array is set to NULL by the application, this parameter
* returns the number of bytes available in the FIFO.
*
* @retval NRF_SUCCESS If the procedure is successful. The actual number of bytes written might
* be less than the requested maximum, depending on how much room there is in
* the FIFO. Even if less bytes are written, the procedure is considered
* successful. If the write was partial, the application should use
* subsequent calls to attempt writing the data again.
* @retval NRF_ERROR_NULL If a NULL parameter was passed for a parameter that must not
* be NULL.
* @retval NRF_ERROR_NO_MEM If the FIFO is full.
*
*/
uint32_t app_fifo_write(app_fifo_t * p_fifo, uint8_t const * p_byte_array, uint32_t * p_size);
#ifdef __cplusplus
}
#endif
#endif // APP_FIFO_H__
/** @} */
下面是.c文件
/**
* Copyright (c) 2013 - 2017, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "sdk_common.h"
#if NRF_MODULE_ENABLED(APP_FIFO)
#include "app_fifo.h"
static __INLINE uint32_t fifo_length(app_fifo_t * p_fifo)
{
uint32_t tmp = p_fifo->read_pos;
return p_fifo->write_pos - tmp;
}
#define FIFO_LENGTH() fifo_length(p_fifo) /**< Macro for calculating the FIFO length. */
/**@brief Put one byte to the FIFO. */
static __INLINE void fifo_put(app_fifo_t * p_fifo, uint8_t byte)
{
p_fifo->p_buf[p_fifo->write_pos & p_fifo->buf_size_mask] = byte;
p_fifo->write_pos++;
}
/**@brief Look at one byte in the FIFO. */
static __INLINE void fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte)
{
*p_byte = p_fifo->p_buf[(p_fifo->read_pos + index) & p_fifo->buf_size_mask];
}
/**@brief Get one byte from the FIFO. */
static __INLINE void fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte)
{
fifo_peek(p_fifo, 0, p_byte);
p_fifo->read_pos++;
}
uint32_t app_fifo_init(app_fifo_t * p_fifo, uint8_t * p_buf, uint16_t buf_size)
{
// Check buffer for null pointer.
if (p_buf == NULL)
{
return NRF_ERROR_NULL;
}
// Check that the buffer size is a power of two.
if (!IS_POWER_OF_TWO(buf_size))
{
return NRF_ERROR_INVALID_LENGTH;
}
p_fifo->p_buf = p_buf;
p_fifo->buf_size_mask = buf_size - 1;
p_fifo->read_pos = 0;
p_fifo->write_pos = 0;
return NRF_SUCCESS;
}
uint32_t app_fifo_put(app_fifo_t * p_fifo, uint8_t byte)
{
if (FIFO_LENGTH() <= p_fifo->buf_size_mask)
{
fifo_put(p_fifo, byte);
return NRF_SUCCESS;
}
return NRF_ERROR_NO_MEM;
}
uint32_t app_fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte)
{
if (FIFO_LENGTH() != 0)
{
fifo_get(p_fifo, p_byte);
return NRF_SUCCESS;
}
return NRF_ERROR_NOT_FOUND;
}
uint32_t app_fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte)
{
if (FIFO_LENGTH() > index)
{
fifo_peek(p_fifo, index, p_byte);
return NRF_SUCCESS;
}
return NRF_ERROR_NOT_FOUND;
}
uint32_t app_fifo_flush(app_fifo_t * p_fifo)
{
p_fifo->read_pos = p_fifo->write_pos;
return NRF_SUCCESS;
}
uint32_t app_fifo_read(app_fifo_t * p_fifo, uint8_t * p_byte_array, uint32_t * p_size)
{
VERIFY_PARAM_NOT_NULL(p_fifo);
VERIFY_PARAM_NOT_NULL(p_size);
const uint32_t byte_count = fifo_length(p_fifo);
const uint32_t requested_len = (*p_size);
uint32_t index = 0;
uint32_t read_size = MIN(requested_len, byte_count);
(*p_size) = byte_count;
// Check if the FIFO is empty.
if (byte_count == 0)
{
return NRF_ERROR_NOT_FOUND;
}
// Check if application has requested only the size.
if (p_byte_array == NULL)
{
return NRF_SUCCESS;
}
// Fetch bytes from the FIFO.
while (index < read_size)
{
fifo_get(p_fifo, &p_byte_array[index++]);
}
(*p_size) = read_size;
return NRF_SUCCESS;
}
uint32_t app_fifo_write(app_fifo_t * p_fifo, uint8_t const * p_byte_array, uint32_t * p_size)
{
VERIFY_PARAM_NOT_NULL(p_fifo);
VERIFY_PARAM_NOT_NULL(p_size);
const uint32_t available_count = p_fifo->buf_size_mask - fifo_length(p_fifo) + 1;
const uint32_t requested_len = (*p_size);
uint32_t index = 0;
uint32_t write_size = MIN(requested_len, available_count);
(*p_size) = available_count;
// Check if the FIFO is FULL.
if (available_count == 0)
{
return NRF_ERROR_NO_MEM;
}
// Check if application has requested only the size.
if (p_byte_array == NULL)
{
return NRF_SUCCESS;
}
//Fetch bytes from the FIFO.
while (index < write_size)
{
fifo_put(p_fifo, p_byte_array[index++]);
}
(*p_size) = write_size;
return NRF_SUCCESS;
}
#endif //NRF_MODULE_ENABLED(APP_FIFO)