--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/network/torrent/ratecontroller.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,156 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "peerwireclient.h"
+#include "ratecontroller.h"
+
+#include <QtCore>
+
+Q_GLOBAL_STATIC(RateController, rateController)
+
+RateController *RateController::instance()
+{
+    return rateController();
+}
+
+void RateController::addSocket(PeerWireClient *socket)
+{
+    connect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
+    socket->setReadBufferSize(downLimit * 4);
+    sockets << socket;
+    scheduleTransfer();
+}
+
+void RateController::removeSocket(PeerWireClient *socket)
+{
+    disconnect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
+    socket->setReadBufferSize(0);
+    sockets.remove(socket);
+}
+
+void RateController::setDownloadLimit(int bytesPerSecond)
+{
+    downLimit = bytesPerSecond;
+    foreach (PeerWireClient *socket, sockets)
+        socket->setReadBufferSize(downLimit * 4);
+}
+
+void RateController::scheduleTransfer()
+{
+    if (transferScheduled)
+        return;
+    transferScheduled = true;
+    QTimer::singleShot(50, this, SLOT(transfer()));
+}
+
+void RateController::transfer()
+{
+    transferScheduled = false;
+    if (sockets.isEmpty())
+        return;
+
+    int msecs = 1000;
+    if (!stopWatch.isNull())
+        msecs = qMin(msecs, stopWatch.elapsed());
+
+    qint64 bytesToWrite = (upLimit * msecs) / 1000;
+    qint64 bytesToRead = (downLimit * msecs) / 1000;
+    if (bytesToWrite == 0 && bytesToRead == 0) {
+        scheduleTransfer();
+        return;
+    }
+
+    QSet<PeerWireClient *> pendingSockets;
+    foreach (PeerWireClient *client, sockets) {
+        if (client->canTransferMore())
+            pendingSockets << client;
+    }
+    if (pendingSockets.isEmpty())
+        return;
+
+    stopWatch.start();
+
+    bool canTransferMore;
+    do {
+        canTransferMore = false;
+        qint64 writeChunk = qMax<qint64>(1, bytesToWrite / pendingSockets.size());
+        qint64 readChunk = qMax<qint64>(1, bytesToRead / pendingSockets.size());
+
+        QSetIterator<PeerWireClient *> it(pendingSockets);
+        while (it.hasNext() && (bytesToWrite > 0 || bytesToRead > 0)) {
+            PeerWireClient *socket = it.next();
+            if (socket->state() != QAbstractSocket::ConnectedState) {
+                pendingSockets.remove(socket);
+                continue;
+            }
+
+            bool dataTransferred = false;
+            qint64 available = qMin<qint64>(socket->socketBytesAvailable(), readChunk);
+            if (available > 0) {
+                qint64 readBytes = socket->readFromSocket(qMin<qint64>(available, bytesToRead));
+                if (readBytes > 0) {
+                    bytesToRead -= readBytes;
+                    dataTransferred = true;
+                }
+            }
+
+            if (upLimit * 2 > socket->bytesToWrite()) {
+                qint64 chunkSize = qMin<qint64>(writeChunk, bytesToWrite);
+                qint64 toWrite = qMin(upLimit * 2 - socket->bytesToWrite(), chunkSize);
+                if (toWrite > 0) {
+                    qint64 writtenBytes = socket->writeToSocket(toWrite);
+                    if (writtenBytes > 0) {
+                        bytesToWrite -= writtenBytes;
+                        dataTransferred = true;
+                    }
+                }
+            }
+
+            if (dataTransferred && socket->canTransferMore())
+                canTransferMore = true;
+            else
+                pendingSockets.remove(socket);
+        }
+    } while (canTransferMore && (bytesToWrite > 0 || bytesToRead > 0) && !pendingSockets.isEmpty());
+
+    if (canTransferMore || bytesToWrite == 0 || bytesToRead == 0)
+        scheduleTransfer();
+}