Add ConcurrentQueue implementation.

Change-Id: I28224d07c0b093bd520f0a1038cc808b1fac626c

src/support/ConcurrentQueue.h

@@ -0,0 +1,68 @@
+//
+// Copyright (c) 2013 Juan Palacios juan.palacios.puyana@gmail.com
+// Subject to the BSD 2-Clause License
+// - see < http://opensource.org/licenses/BSD-2-Clause>
+//
+
+#ifndef CONCURRENT_QUEUE_
+#define CONCURRENT_QUEUE_
+
+#include <queue>
+#include <thread>
+#include <mutex>
+#include <condition_variable>
+
+template <typename T>
+class ConcurrentQueue
+{
+public:
+    T pop() 
+    {
+        std::unique_lock<std::mutex> mlock(mutex_);
+        while (queue_.empty())
+        {
+            cond_.wait(mlock);
+        }
+        auto item = std::move(queue_.front());
+        queue_.pop();
+        return item;
+    }
+
+    void pop(T& item)
+    {
+        std::unique_lock<std::mutex> mlock(mutex_);
+        while (queue_.empty())
+        {
+            cond_.wait(mlock);
+        }
+        item = queue_.front();
+        queue_.pop();
+    }
+
+    void push(const T& item)
+    {
+        std::unique_lock<std::mutex> mlock(mutex_);
+        queue_.push(item);
+        mlock.unlock();
+        cond_.notify_one();
+    }
+
+    void push(T&& item)
+    {
+        std::unique_lock<std::mutex> mlock(mutex_);
+        queue_.push(std::move(item));
+        mlock.unlock();
+        cond_.notify_one();
+    }
+
+    ConcurrentQueue() = default;
+    ConcurrentQueue(const ConcurrentQueue&) = delete;
+    ConcurrentQueue& operator=(const ConcurrentQueue&) = delete;
+  
+private:
+    std::queue<T> queue_;
+    std::mutex mutex_;
+    std::condition_variable cond_;
+};
+
+#endif