Long live the TuioTouch input plugin!

This is an import of the tuio2qt plugin (https://github.com/rburchell/tuio2qt),
as of sha 9b1f163ac52ea440e83f16b3906f9b55e21b87be henceforth to be developed as
a part of Qt itself.

This plugin offers touch events via QPA interfaces, using data offered over the
TUIO protocol (http://www.tuio.org).

It is useful for accepting touch input on devices which otherwise don't have
touch input (such as desktops) for the purposes of development, as well as
accepting input from some hardware which offers up touch events specifically
over the TUIO protocol.

Known "shortcomings" at this time, as documented in the README:
 * Multiple TUIO sources sending data at the same time will conflict. This will
   not cause problems, strictly speaking, but it will not work well (repeated
   touchpoint release/press events for the same IDs)
 * TCP transport is not currently supported. I don't see a need for it at this
   time, but I have left the capability in terms of port acceptance open for it
   to be made available.

Change-Id: I7178f9db13c635268db8460fbe4d4ea6be654c05
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

1 files changed, 186 insertions, 0 deletions

diff --git a/src/plugins/generic/tuiotouch/qoscbundle.cpp b/src/plugins/generic/tuiotouch/qoscbundle.cpp
new file mode 100644
index 0000000000..39e1bdcd81
--- /dev/null
+++ b/src/plugins/generic/tuiotouch/qoscbundle.cpp
@@ -0,0 +1,186 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Robin Burchell <robin.burchell@viroteck.net>
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights. These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtEndian>
+#include <QDebug>
+#include <QLoggingCategory>
+
+#include "qoscbundle_p.h"
+#include "qtuio_p.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(lcTuioBundle, "qt.qpa.tuio.bundle")
+
+// TUIO packets are transmitted using the OSC protocol, located at:
+//   http://opensoundcontrol.org/specification
+// Snippets of this specification have been pasted into the source as a means of
+// easily communicating requirements.
+
+QOscBundle::QOscBundle(const QByteArray &data)
+    : m_isValid(false)
+    , m_immediate(false)
+    , m_timeEpoch(0)
+    , m_timePico(0)
+{
+    // 8  16 24 32 40 48 56 64
+    // #  b  u  n  d  l  e  \0
+    // 23 62 75 6e 64 6c 65 00 // OSC string bundle identifier
+    // 00 00 00 00 00 00 00 01 // osc time-tag, "immediately"
+    // 00 00 00 30 // element length
+    //      => message or bundle(s), preceded by length each time
+    qCDebug(lcTuioBundle) << data.toHex();
+    quint32 parsedBytes = 0;
+
+    // "An OSC Bundle consists of the OSC-string "#bundle""
+    QByteArray identifier;
+    if (!qt_readOscString(data, identifier, parsedBytes) || identifier != "#bundle")
+        return;
+
+    // "followed by an OSC Time
+    // Tag, followed by zero or more OSC Bundle Elements. The OSC-timetag is a
+    // 64-bit fixed point time tag whose semantics are described below."
+    if (parsedBytes > (quint32)data.size() || data.size() - parsedBytes < sizeof(quint64))
+        return;
+
+    // "Time tags are represented by a 64 bit fixed point number. The first 32
+    // bits specify the number of seconds since midnight on January 1,  1900,
+    // and the last 32 bits specify fractional parts of a second to a precision
+    // of about 200 picoseconds. This is the representation used by Internet NTP
+    // timestamps."
+    //
+    // (editor's note: one may wonder how a 64bit big-endian number can also be
+    // two 32bit numbers, without specifying in which order they occur or
+    // anything, and one may indeed continue to wonder.)
+    quint32 oscTimeEpoch = qFromBigEndian<quint32>((const uchar*)data.constData() + parsedBytes);
+    parsedBytes += sizeof(quint32);
+    quint32 oscTimePico = qFromBigEndian<quint32>((const uchar*)data.constData() + parsedBytes);
+    parsedBytes += sizeof(quint32);
+
+    bool isImmediate = false;
+
+    if (oscTimeEpoch == 0 && oscTimePico == 1) {
+        // "The time tag value consisting of 63 zero bits followed by a
+        // one in the least signifigant bit is a special case meaning
+        // "immediately.""
+        isImmediate = true;
+    }
+
+    while (parsedBytes < (quint32)data.size()) {
+        // "An OSC Bundle Element consists of its size and its contents. The size is an
+        // int32 representing the number of 8-bit bytes in the contents, and will
+        // always be a multiple of 4."
+        //
+        // in practice, a bundle can contain multiple bundles or messages,
+        // though, and each is prefixed by a size.
+        if (data.size() - parsedBytes < sizeof(quint32))
+            return;
+
+        quint32 size = qFromBigEndian<quint32>((const uchar*)data.constData() + parsedBytes);
+        parsedBytes += sizeof(quint32);
+
+        if (data.size() - parsedBytes < size)
+            return;
+
+        if (size == 0) {
+            // empty bundle; these are valid, but should they be allowed? the
+            // spec is unclear on this...
+            qWarning() << "Empty bundle?";
+            m_isValid = true;
+            m_immediate = isImmediate;
+            m_timeEpoch = oscTimeEpoch;
+            m_timePico = oscTimePico;
+            return;
+        }
+
+        // "The contents are either an OSC Message or an OSC Bundle.
+        // Note this recursive definition: bundle may contain bundles."
+        QByteArray subdata = data.mid(parsedBytes, size);
+        parsedBytes += size;
+
+        // "The contents of an OSC packet must be either an OSC Message or an OSC Bundle.
+        // The first byte of the packet's contents unambiguously distinguishes between
+        // these two alternatives."
+        //
+        // we're not dealing with a packet here, but the same trick works just
+        // the same.
+        QByteArray bundleIdentifier = QByteArray("#bundle\0",  8);
+        if (subdata.startsWith('/')) {
+            // starts with / => address pattern => start of a message
+            QOscMessage subMessage(subdata);
+            if (subMessage.isValid()) {
+                m_isValid = true;
+                m_immediate = isImmediate;
+                m_timeEpoch = oscTimeEpoch;
+                m_timePico = oscTimePico;
+                m_messages.append(subMessage);
+            } else {
+                qWarning() << "Invalid sub-message";
+                return;
+            }
+        } else if (subdata.startsWith(bundleIdentifier)) {
+            // bundle identifier start => bundle
+            QOscBundle subBundle(subdata);
+            if (subBundle.isValid()) {
+                m_isValid = true;
+                m_immediate = isImmediate;
+                m_timeEpoch = oscTimeEpoch;
+                m_timePico = oscTimePico;
+                m_bundles.append(subBundle);
+            }
+        } else {
+            qWarning() << "Malformed sub-data!";
+            return;
+        }
+    }
+}
+
+
+bool QOscBundle::isValid() const
+{
+    return m_isValid;
+}
+
+QList<QOscBundle> QOscBundle::bundles() const
+{
+    return m_bundles;
+}
+
+QList<QOscMessage> QOscBundle::messages() const
+{
+    return m_messages;
+}
+
+QT_END_NAMESPACE
+