Refactored CL for moving the output to a separate thread.

webrtc/call/ringbuffer.h

+/*
+ *  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 "webrtc/base/checks.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) {
+    RTC_DCHECK(capacity > 0);
+    data_ = new T[capacity + 1];
+    end_ = data_ + (capacity + 1);
+    front_ = data_;
+    back_ = data_;
+  }
+  ~RingBuffer() {
+    delete[] data_;
+  }
+
+  // Removes an element from the front of the queue.
+  void pop_front() {
+    RTC_DCHECK(!empty());
+    front_++;
+    if (front_ == end_) {
+      front_ = data_;
+    }
+  }
+
+  // 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_;
+    }
+    if (back_ == front_) {
+      front_++;
+    }
+    if (front_ == end_) {
+      front_ = data_;
+    }
+  }
+
+  T& front() {
+    return *front_;
+  }
+
+  const T& front() const {
+    return *front_;
+  }
+
+  bool empty() const {
+    return (front_ == back_);
+  }
+
+ private:
+  T* data_;
+  T* end_;
+  T* front_;
+  T* back_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RingBuffer);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_CALL_RINGBUFFER_H_