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/******************************************************************************\
* Copyright (c) 2004-2020
*
* Author(s):
* Julian Santander
*
******************************************************************************
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*
\******************************************************************************/
#pragma once
#include <vector>
/**
* Implementantion of a ring buffer.
* Data is contained in a vector dynamically allocated.
*/
template<typename T>
class RingBuffer {
public:
/**
* @brief RingBuffer
* @param max maximum number of elements that can be contained in the ring buffer
*/
RingBuffer(std::size_t max = 0):mData(max),mRead(0),mWrite(0),mFull(false) { }
/**
* @brief Resets the ring_buffer
* @param max maximum number of elements that can be contained in the ring buffer.
*/
void reset(std::size_t max = 0) {
mData = std::vector<T>(max);
mRead = 0;
mWrite = 0;
mFull = false;
}
/**
* @brief Current number of elements contained in the ring buffer
* @return
*/
std::size_t size() const {
std::size_t size = capacity();
if(!mFull) {
if(mWrite >= mRead) {
size = mWrite - mRead;
} else {
size = capacity() + mWrite - mRead;
}
}
return size;
}
/**
* @brief whether the ring buffer is full
* @return
*/
bool isFull() const { return mFull; }
/**
* @brief whether the ring buffer is empty.
* @return
*/
bool isEmpty() const { return !isFull() && (mRead == mWrite); }
/**
* @brief Maximum number of elements in the ring buffer
* @return
*/
std::size_t capacity() const { return mData.size(); }
/**
* @brief Adds a single value
* @param v the value to add
*/
void put(const T &v) {
mData[mWrite] = v;
forward();
}
/**
* @brief Reads a single value
* @param v the value read
* @return true if the value was read
*/
bool get(T&v) {
if(!isEmpty()) {
v = mData[mRead];
backward();
return true;
} else {
return false;
}
}
/**
* @brief Adds a multiple consecutive values
* @param v pointer to the consecutive values
* @param count number of consecutive values.
*/
void put(const T *v, std::size_t count) {
std::size_t avail = mWrite - capacity();
std::size_t to_copy = std::min(count,avail);
memcpy(mData.data() + mWrite,v, to_copy*sizeof(T));
forward(to_copy);
if(to_copy < count) {
put(v+to_copy,count - to_copy);
}
}
/**
* @brief Reads multiple values
* @param v pointer to the memory wher ethe values will be written
* @param count Maximum available size in the memory area
* @return actual number of elements read.
*/
std::size_t get(T *v, std::size_t count) {
std::size_t avail = 0;
if(mRead < mWrite) {
avail = mWrite - mRead;
} else {
avail = mRead - capacity();
}
std::size_t to_copy = std::min(count, avail);
memcpy(v, mData.data() + mRead, to_copy * sizeof(T));
backward(to_copy);
if((size()>0)&&(count > to_copy)) {
return to_copy + get(v + to_copy, count - to_copy);
} else {
return to_copy;
}
}
private:
void forward() {
if(isFull()) {
mRead = (mRead + 1) % capacity();
}
mWrite = (mWrite + 1) % capacity();
mFull = (mRead == mWrite);
}
void forward(std::size_t count) {
for(std::size_t i=0; i<count;i++) {
forward();
}
}
void backward(std::size_t count) {
mFull = false;
mRead = (mRead + count) % capacity();
}
std::vector<T> mData;
std::size_t mRead; /** offset to reading point */
std::size_t mWrite; /** offset to writing point */
bool mFull;
};
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