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==Create QDataStream from QBuffer==

<source lang="cpp">
/****************************************************************************
**
** 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 documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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.
**
** 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QApplication>
#include <QBuffer>
#include <QPalette>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QByteArray byteArray;
QBuffer buffer(&byteArray);
buffer.open(QIODevice::WriteOnly);
QDataStream out(&buffer);
out << QApplication::palette();
return 0;
}

</source>

==Read datastream==

<source lang="cpp">
/****************************************************************************
**
** 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 documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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.
**
** 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QApplication>
#include <QBuffer>
#include <QPalette>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QByteArray byteArray;

QPalette palette;
QBuffer buffer(&byteArray);
buffer.open(QIODevice::ReadOnly);
QDataStream in(&buffer);
in >> palette;
return 0;
}

</source>

==Saving file with QDataStream==

<source lang="cpp">

Foundations of Qt Development\Chapter08\datastream\main.cpp
/*
* Copyright (c) 2006-2007, Johan Thelin
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of APress nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <QFile>
#include <QDataStream>
#include <QList>
#include <QColor>
#include <QtDebug>
struct ColorText
{
QString text;
QColor color;
};
QDataStream &operator<<( QDataStream &stream, const ColorText &data )
{
stream << data.text << data.color;

return stream;
}
QDataStream &operator>>( QDataStream &stream, ColorText &data )
{
stream >> data.text;
stream >> data.color;

return stream;
}
void saveList()
{
QList<ColorText> list;
ColorText data;

data.text = "Red";
data.color = Qt::red;
list << data;

data.text = "Blue";
data.color = Qt::blue;
list << data;
data.text = "Yellow";
data.color = Qt::yellow;
list << data;
data.text = "Green";
data.color = Qt::green;
list << data;

QFile file( "test.dat" );
if( !file.open( QIODevice::WriteOnly ) )
return;

QDataStream stream( &file );
stream.setVersion( QDataStream::Qt_4_2 );

stream << list;

file.close();
}
void loadList()
{
QList<ColorText> list;

QFile file( "test.dat" );
if( !file.open( QIODevice::ReadOnly ) )
return;

QDataStream stream( &file );
stream.setVersion( QDataStream::Qt_4_2 );
stream >> list;

file.close();
foreach( ColorText data, list )
qDebug() << data.text << "("
<< data.color.red() << ","
<< data.color.green() << ","
<< data.color.blue() << ")";
}
int main( int argc, char **argv )
{
saveList();
loadList();

return 0;
}

</source>

==Serialization with QDataStream==

<source lang="cpp">

/****************************************************************************
**
** 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 documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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.
**
** 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
#include <QByteArray>
#include <QDataStream>

struct Movie
{
int id;
QString title;
QDate releaseDate;
};

QDataStream &operator<<(QDataStream &out, const Movie &movie)
{
out << (quint32)movie.id << movie.title
<< movie.releaseDate;
return out;
}

QDataStream &operator>>(QDataStream &in, Movie &movie)
{
quint32 id;
QDate date;
in >> id >> movie.title >> date;
movie.id = (int)id;
movie.releaseDate = date;
return in;
}

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
Movie m;
m.id = 0001;
m.title = "Happy Meal";
m.releaseDate = QDate(1995, 5, 17);
QByteArray byteArray;
QDataStream stream(&byteArray, QIODevice::WriteOnly);
stream << m;

// display
qDebug() << m.id << m.releaseDate << m.title;
Movie m2;

int id2;
QString title2;
QDate date2;
QDataStream stream2(byteArray);
stream2 >> id2 >> title2 >> date2;
m2.id = id2;
m2.title = title2;
m2.releaseDate = date2;
qDebug() << id2 << " " << date2 << " " << title2;
return 0;
}

</source>

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C++/Qt/QDataStream - История изменений

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