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#ifndef RING_BUFFER_INCLUDED
#define RING_BUFFER_INCLUDED
/**************************************************************************//**
* @file
* A ring buffer.
*
* License
* -------
*
* Copyright © 2017 AT&T Intellectual Property. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*****************************************************************************/
#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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