Add a QAudioBuffer class.

Prereq for probing or decoding.  The abstract API probably needs
to change.

Change-Id: Ie0bf796c1f581f34bbc0a8af2dffc387c513a330
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

src/multimedia/audio/qaudiobuffer_p.h

@@ -0,0 +1,90 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QAUDIOBUFFER_P_H
+#define QAUDIOBUFFER_P_H
+
+#include <qtmultimediadefs.h>
+#include <qtmedianamespace.h>
+
+#include "qaudioformat.h"
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Multimedia)
+
+class Q_MULTIMEDIA_EXPORT QAbstractAudioBuffer {
+public:
+    virtual ~QAbstractAudioBuffer() {}
+
+    // Lifetime management
+    virtual void release() = 0;
+
+    // Format related
+    virtual QAudioFormat format() const = 0;
+    virtual qint64 startTime() const = 0;
+    virtual int sampleCount() const = 0;
+
+    // R/O Data
+    virtual void *constData() const = 0;
+
+    // For writable data we do this:
+    // If we only have one reference to the provider,
+    // call writableData().  If that does not return 0,
+    // then we're finished.  If it does return 0, then we call
+    // writableClone() to get a new buffer and then release
+    // the old clone if that succeeds.  If it fails, we create
+    // a memory clone from the constData and release the old buffer.
+    // If writableClone() succeeds, we then call writableData() on it
+    // and that should be good.
+
+    virtual void *writableData() = 0;
+    virtual QAbstractAudioBuffer *clone() const = 0;
+};
+
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QAUDIOBUFFER_P_H