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/*
* STMicroelectronics Circular Buffer Class
*
* Copyright 2013-2015 STMicroelectronics Inc.
* Author: Denis Ciocca - <denis.ciocca@st.com>
*
* Licensed under the Apache License, Version 2.0 (the "License").
*/
#include "CircularBuffer.h"
#include <stdlib.h>
#include <string.h>
#include <cutils/log.h>
CircularBuffer::CircularBuffer(unsigned int num_elements)
{
data_sensor = (SensorBaseData *)malloc(num_elements * sizeof(SensorBaseData));
pthread_mutex_init(&data_mutex, NULL);
lenght = num_elements;
elements_available = 0;
first_free_element = &data_sensor[0];
first_available_element = &data_sensor[0];
}
CircularBuffer::~CircularBuffer()
{
delete data_sensor;
}
void CircularBuffer::writeElement(SensorBaseData *data)
{
pthread_mutex_lock(&data_mutex);
if (elements_available == lenght) {
first_available_element++;
if (first_available_element == (&data_sensor[0] + lenght))
first_available_element = &data_sensor[0];
}
memcpy(first_free_element, data, sizeof(SensorBaseData));
first_free_element++;
if (first_free_element == (&data_sensor[0] + lenght))
first_free_element = &data_sensor[0];
if (elements_available < lenght)
elements_available++;
pthread_mutex_unlock(&data_mutex);
}
int CircularBuffer::readElement(SensorBaseData *data)
{
int num_remaining_elements;
pthread_mutex_lock(&data_mutex);
if (elements_available == 0) {
pthread_mutex_unlock(&data_mutex);
return -EFAULT;
}
memcpy(data, first_available_element, sizeof(SensorBaseData));
first_available_element++;
if (first_available_element == (&data_sensor[0] + lenght))
first_available_element = &data_sensor[0];
elements_available--;
num_remaining_elements = elements_available;
pthread_mutex_unlock(&data_mutex);
return num_remaining_elements;
}
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