rhubarb-lip-sync/lib/webrtc-8d2248ff/webrtc/call/ringbuffer.h

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2016-06-21 20:13:05 +00:00
/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*
*/
#ifndef WEBRTC_CALL_RINGBUFFER_H_
#define WEBRTC_CALL_RINGBUFFER_H_
#include <memory>
#include <utility>
#include "webrtc/base/checks.h"
#include "webrtc/base/constructormagic.h"
namespace webrtc {
// A RingBuffer works like a fixed size queue which starts discarding
// the oldest elements when it becomes full.
template <typename T>
class RingBuffer {
public:
// Creates a RingBuffer with space for |capacity| elements.
explicit RingBuffer(size_t capacity)
: // We allocate space for one extra sentinel element.
data_(new T[capacity + 1]) {
RTC_DCHECK(capacity > 0);
end_ = data_.get() + (capacity + 1);
front_ = data_.get();
back_ = data_.get();
}
~RingBuffer() {
// The unique_ptr will free the memory.
}
// Removes an element from the front of the queue.
void pop_front() {
RTC_DCHECK(!empty());
++front_;
if (front_ == end_) {
front_ = data_.get();
}
}
// Appends an element to the back of the queue (and removes an
// element from the front if there is no space at the back of the queue).
void push_back(const T& elem) {
*back_ = elem;
++back_;
if (back_ == end_) {
back_ = data_.get();
}
if (back_ == front_) {
++front_;
}
if (front_ == end_) {
front_ = data_.get();
}
}
// Appends an element to the back of the queue (and removes an
// element from the front if there is no space at the back of the queue).
void push_back(T&& elem) {
*back_ = std::move(elem);
++back_;
if (back_ == end_) {
back_ = data_.get();
}
if (back_ == front_) {
++front_;
}
if (front_ == end_) {
front_ = data_.get();
}
}
T& front() { return *front_; }
const T& front() const { return *front_; }
bool empty() const { return (front_ == back_); }
private:
std::unique_ptr<T[]> data_;
T* end_;
T* front_;
T* back_;
RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RingBuffer);
};
} // namespace webrtc
#endif // WEBRTC_CALL_RINGBUFFER_H_