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