source: trunk/doc/src/datastreamformat.qdoc@ 321

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/****************************************************************************
**
** Documentation of the Format of the QDataStream operators.
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information ([email protected])
**
** This file is part of the Qt GUI Toolkit.
** EDITIONS: FREE, PROFESSIONAL, ENTERPRISE
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****************************************************************************/

/*!
    \page datastreamformat.html
    \title Format of the QDataStream Operators
    \ingroup architecture
    \brief Representations of data types that can be serialized by QDataStream.

    The \l QDataStream allows you to serialize some of the Qt data types.
    The table below lists the data types that QDataStream can serialize
    and how they are represented. The format described below is
    \l{QDataStream::setVersion()}{version 8}.

    It is always best to cast integers to a Qt integer type, such as
    qint16 or quint32, when reading and writing. This ensures that
    you always know exactly what size integers you are reading and
    writing, no matter what the underlying platform and architecture
    the application happens to be running on.

    \table
    \row \o qint8
         \o \list
            \o signed byte
            \endlist
    \row \o qint16
         \o \list
            \o signed 16-bit integer
            \endlist
    \row \o qint32
         \o \list
            \o signed 32-bit integer
            \endlist
    \row \o qint64
         \o \list
            \o signed 64-bit integer
            \endlist
    \row \o quint8
         \o \list
            \o unsigned byte
            \endlist
    \row \o quint16
         \o \list
            \o unsigned 16-bit integer
            \endlist
    \row \o quint32
         \o \list
            \o unsigned 32-bit integer
            \endlist
    \row \o quint64
         \o \list
            \o unsigned 64-bit integer
            \endlist
    \row \o \c float
         \o \list
            \o 32-bit floating point number using the standard IEEE 754 format
            \endlist
    \row \o \c double
         \o \list
            \o 64-bit floating point number using the standard IEEE 754 format
            \endlist
    \row \o \c {const char *}
         \o \list
            \o The string length (quint32)
            \o The string bytes, excluding the terminating 0
            \endlist
    \row \o QBitArray
         \o \list
            \o The array size (quint32)
            \o The array bits, i.e. (size + 7)/8 bytes
            \endlist
    \row \o QBrush
         \o \list
            \o The brush style (quint8)
            \o The brush color (QColor)
            \o If style is CustomPattern, the brush pixmap (QPixmap)
            \endlist
    \row \o QByteArray
         \o \list
            \o If the byte array is null: 0xFFFFFFFF (quint32)
            \o Otherwise: the array size (quint32) followed by the array bytes, i.e. size bytes
            \endlist
    \row \o \l QColor
         \o \list
            \o Color spec (qint8)
            \o Alpha value (quint16)
            \o Red value (quint16)
            \o Green value (quint16)
            \o Blue value (quint16)
            \o Pad value (quint16)
            \endlist
    \row \o QCursor
         \o \list
            \o Shape ID (qint16)
            \o If shape is BitmapCursor: The bitmap (QPixmap), mask (QPixmap), and hot spot (QPoint)
            \endlist
    \row \o QDate
         \o \list
            \o Julian day (quint32)
            \endlist
    \row \o QDateTime
         \o \list
            \o Date (QDate)
            \o Time (QTime)
            \o 0 for Qt::LocalTime, 1 for Qt::UTC (quint8)
            \endlist
    \row \o QFont
         \o \list
            \o The family (QString)
            \o The point size (qint16)
            \o The style hint (quint8)
            \o The char set (quint8)
            \o The weight (quint8)
            \o The font bits (quint8)
            \endlist
    \row \o QHash<Key, T>
         \o \list
            \o The number of items (quint32)
            \o For all items, the key (Key) and value (T)
            \endlist
    \row \o QIcon
         \o \list
            \o The number of pixmap entries (quint32)
            \o For all pixmap entries:
               \list
               \o The pixmap (QPixmap)
               \o The file name (QString)
               \o The pixmap size (QSize)
               \o The \l{QIcon::Mode}{mode} (quint32)
               \o The \l{QIcon::State}{state} (quint32)
               \endlist
            \endlist
    \row \o QImage
         \o \list
            \o If the image is null a "null image" marker is saved;
            otherwise the image is saved in PNG or BMP format (depending
            on the stream version). If you want control of the format,
            stream the image into a QBuffer (using QImageIO) and stream
            that.
            \endlist
    \row \o QKeySequence
         \o \list
            \o A QList<int>, where each integer is a key in the key sequence
            \endlist
    \row \o QLinkedList<T>
         \o \list
            \o The number of items (quint32)
            \o The items (T)
            \endlist
    \row \o QList<T>
         \o \list
            \o The number of items (quint32)
            \o The items (T)
            \endlist
    \row \o QMap<Key, T>
         \o \list
            \o The number of items (quint32)
            \o For all items, the key (Key) and value (T)
            \endlist
    \row \o QMatrix
         \o \list
            \o m11 (double)
            \o m12 (double)
            \o m21 (double)
            \o m22 (double)
            \o dx (double)
            \o dy (double)
            \endlist
    \row \o QPair<T1, T2>
         \o \list
            \o first (T1)
            \o second (T2)
            \endlist
    \row \o QPalette
         \o The disabled, active, and inactive color groups, each of which consists
            of the following:
            \list
            \o foreground (QBrush)
            \o button (QBrush)
            \o light (QBrush)
            \o midlight (QBrush)
            \o dark (QBrush)
            \o mid (QBrush)
            \o text (QBrush)
            \o brightText (QBrush)