terelius | 4311ba5 | 2016-04-22 12:40:37 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2015 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | * |
| 10 | */ |
| 11 | |
skvlad | cc91d28 | 2016-10-03 18:31:22 -0700 | [diff] [blame^] | 12 | #ifndef WEBRTC_LOGGING_RTC_EVENT_LOG_RINGBUFFER_H_ |
| 13 | #define WEBRTC_LOGGING_RTC_EVENT_LOG_RINGBUFFER_H_ |
terelius | 4311ba5 | 2016-04-22 12:40:37 -0700 | [diff] [blame] | 14 | |
| 15 | #include <memory> |
| 16 | #include <utility> |
| 17 | |
| 18 | #include "webrtc/base/checks.h" |
kwiberg | 4485ffb | 2016-04-26 08:14:39 -0700 | [diff] [blame] | 19 | #include "webrtc/base/constructormagic.h" |
terelius | 4311ba5 | 2016-04-22 12:40:37 -0700 | [diff] [blame] | 20 | |
| 21 | namespace webrtc { |
| 22 | |
| 23 | // A RingBuffer works like a fixed size queue which starts discarding |
| 24 | // the oldest elements when it becomes full. |
| 25 | template <typename T> |
| 26 | class RingBuffer { |
| 27 | public: |
| 28 | // Creates a RingBuffer with space for |capacity| elements. |
| 29 | explicit RingBuffer(size_t capacity) |
| 30 | : // We allocate space for one extra sentinel element. |
| 31 | data_(new T[capacity + 1]) { |
| 32 | RTC_DCHECK(capacity > 0); |
| 33 | end_ = data_.get() + (capacity + 1); |
| 34 | front_ = data_.get(); |
| 35 | back_ = data_.get(); |
| 36 | } |
| 37 | |
| 38 | ~RingBuffer() { |
| 39 | // The unique_ptr will free the memory. |
| 40 | } |
| 41 | |
| 42 | // Removes an element from the front of the queue. |
| 43 | void pop_front() { |
| 44 | RTC_DCHECK(!empty()); |
| 45 | ++front_; |
| 46 | if (front_ == end_) { |
| 47 | front_ = data_.get(); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | // Appends an element to the back of the queue (and removes an |
| 52 | // element from the front if there is no space at the back of the queue). |
| 53 | void push_back(const T& elem) { |
| 54 | *back_ = elem; |
| 55 | ++back_; |
| 56 | if (back_ == end_) { |
| 57 | back_ = data_.get(); |
| 58 | } |
| 59 | if (back_ == front_) { |
| 60 | ++front_; |
| 61 | } |
| 62 | if (front_ == end_) { |
| 63 | front_ = data_.get(); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | // Appends an element to the back of the queue (and removes an |
| 68 | // element from the front if there is no space at the back of the queue). |
| 69 | void push_back(T&& elem) { |
| 70 | *back_ = std::move(elem); |
| 71 | ++back_; |
| 72 | if (back_ == end_) { |
| 73 | back_ = data_.get(); |
| 74 | } |
| 75 | if (back_ == front_) { |
| 76 | ++front_; |
| 77 | } |
| 78 | if (front_ == end_) { |
| 79 | front_ = data_.get(); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | T& front() { return *front_; } |
| 84 | |
| 85 | const T& front() const { return *front_; } |
| 86 | |
| 87 | bool empty() const { return (front_ == back_); } |
| 88 | |
| 89 | private: |
| 90 | std::unique_ptr<T[]> data_; |
| 91 | T* end_; |
| 92 | T* front_; |
| 93 | T* back_; |
| 94 | |
| 95 | RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RingBuffer); |
| 96 | }; |
| 97 | |
| 98 | } // namespace webrtc |
| 99 | |
skvlad | cc91d28 | 2016-10-03 18:31:22 -0700 | [diff] [blame^] | 100 | #endif // WEBRTC_LOGGING_RTC_EVENT_LOG_RINGBUFFER_H_ |