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#ifndef RING_BUFFER_INCLUDED
#define RING_BUFFER_INCLUDED
/**************************************************************************//**
* @file
* A ring buffer.
*
* License
* -------
*
* Copyright(c) <2016>, AT&T Intellectual Property. All other 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 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement: This product includes
* software developed by the AT&T.
* 4. Neither the name of AT&T nor the names of its contributors may be used to
* endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY AT&T INTELLECTUAL PROPERTY ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL AT&T INTELLECTUAL PROPERTY 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 <pthread.h>
/**************************************************************************//**
* Ring buffer structure.
*****************************************************************************/
typedef struct ring_buffer
{
int size;
int next_write;
int next_read;
void ** ring;
pthread_cond_t ring_cv;
pthread_mutex_t ring_mutex;
} ring_buffer;
/**************************************************************************//**
* Ring buffer initialization.
*
* Initialize the buffer supplied to the specified size.
*
* @param buffer Pointer to the ring-buffer to be initialized.
* @param size How many elements to be stored in the ring-buffer.
*
* @returns Nothing
******************************************************************************/
void ring_buffer_initialize(ring_buffer * buffer, int size);
/**************************************************************************//**
* Read an element from a ring_buffer.
*
* Reads an element from the ring_buffer, advancing the next-read position.
* Operation is synchronized and therefore MT-safe. Blocks if no data is
* available.
*
* @param buffer Pointer to the ring-buffer to be read.
*
* @returns Pointer to the element read from the buffer.
******************************************************************************/
void * ring_buffer_read(ring_buffer * buffer);
/**************************************************************************//**
* Write an element into a ring_buffer.
*
* Writes an element into the ring_buffer, advancing the next-write position.
* Operation is synchronized and therefore MT-safe. Fails if the buffer is
* full without blocking.
*
* @param buffer Pointer to the ring-buffer to be written.
* @param msg Pointer to data to be stored in the ring_buffer.
*
* @returns Number of items written.
* @retval 1 The data was written successfully.
* @retval 0 The ring_buffer was full so no data written.
******************************************************************************/
int ring_buffer_write(ring_buffer * buffer, void * msg);
/**************************************************************************//**
* Tests whether there is data in the ring_buffer.
*
* Tests whether there is currently data in the ring_buffer without blocking.
*
* @param buffer Pointer to the ring-buffer to be tested.
*
* @returns Whether there is data in the ring_buffer.
* @retval 0 There isn't any data in the ring_buffer.
* @retval 1 There is data in the ring_buffer.
******************************************************************************/
int ring_buffer_is_empty(ring_buffer * buffer);
#endif
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