Add missing ThreadsafeQueue.h

1 files changed, 144 insertions, 0 deletions

diff --git a/src/ThreadsafeQueue.h b/src/ThreadsafeQueue.h
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+/*
+   Copyright (C) 2007, 2008, 2009, 2010, 2011 Her Majesty the Queen in
+   Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2013, 2014
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+   An implementation for a threadsafe queue using boost thread library
+
+   When creating a ThreadsafeQueue, one can specify the minimal number
+   of elements it must contain before it is possible to take one
+   element out.
+ */
+/*
+   This file is part of ODR-DabMux.
+
+   ODR-DabMux is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of the
+   License, or (at your option) any later version.
+
+   ODR-DabMux is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with ODR-DabMux.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef THREADSAFE_QUEUE_H
+#define THREADSAFE_QUEUE_H
+
+#include <boost/thread.hpp>
+#include <queue>
+
+/* This queue is meant to be used by two threads. One producer
+ * that pushes elements into the queue, and one consumer that
+ * retrieves the elements.
+ *
+ * The queue can make the consumer block until an element
+ * is available.
+ */
+
+template<typename T>
+class ThreadsafeQueue
+{
+public:
+    /* Push one element into the queue, and notify another thread that
+     * might be waiting.
+     *
+     * returns the new queue size.
+     */
+    size_t push(T const& val)
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        the_queue.push(val);
+        size_t queue_size = the_queue.size();
+        lock.unlock();
+
+        the_rx_notification.notify_one();
+
+        return queue_size;
+    }
+
+    /* Push one element into the queue, but wait until the
+     * queue size goes below the threshold.
+     *
+     * Notify waiting thread.
+     *
+     * returns the new queue size.
+     */
+    size_t push_wait_if_full(T const& val, size_t threshold)
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        while (the_queue.size() >= threshold) {
+            the_tx_notification.wait(lock);
+        }
+        the_queue.push(val);
+        size_t queue_size = the_queue.size();
+        lock.unlock();
+
+        the_rx_notification.notify_one();
+
+        return queue_size;
+    }
+
+    /* Send a notification for the receiver thread */
+    void notify(void)
+    {
+        the_rx_notification.notify_one();
+    }
+
+    bool empty() const
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        return the_queue.empty();
+    }
+
+    size_t size() const
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        return the_queue.size();
+    }
+
+    bool try_pop(T& popped_value)
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        if (the_queue.empty()) {
+            return false;
+        }
+
+        popped_value = the_queue.front();
+        the_queue.pop();
+
+        lock.unlock();
+        the_tx_notification.notify_one();
+
+        return true;
+    }
+
+    void wait_and_pop(T& popped_value, size_t prebuffering = 1)
+    {
+        boost::mutex::scoped_lock lock(the_mutex);
+        while (the_queue.size() < prebuffering) {
+            the_rx_notification.wait(lock);
+        }
+
+        popped_value = the_queue.front();
+        the_queue.pop();
+
+        lock.unlock();
+        the_tx_notification.notify_one();
+    }
+
+private:
+    std::queue<T> the_queue;
+    mutable boost::mutex the_mutex;
+    boost::condition_variable the_rx_notification;
+    boost::condition_variable the_tx_notification;
+};
+
+#endif
+