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[править] Format of the QDataStream Operators

The 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 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.

qint8	signed byte
qint16	signed 16-bit integer
qint32	signed 32-bit integer
qint64	signed 64-bit integer
quint8	unsigned byte
quint16	unsigned 16-bit integer
quint32	unsigned 32-bit integer
quint64	unsigned 64-bit integer
float	32-bit floating point number using the standard IEEE 754 format
double	64-bit floating point number using the standard IEEE 754 format
const char *	The string length (quint32) The string bytes, excluding the terminating 0
QBitArray	The array size (quint32) The array bits, i.e. (size + 7)/8 bytes
QBrush	The brush style (quint8) The brush color ( QColor) If style is CustomPattern, the brush pixmap ( QPixmap)
QByteArray	If the byte array is null: 0xFFFFFFFF (quint32) Otherwise: the array size (quint32) followed by the array bytes, i.e. size bytes
QColor	RGB value serialized as a quint32
QCursor	Shape ID (qint16) If shape is BitmapCursor: The bitmap ( QPixmap), mask ( QPixmap), and hot spot ( QPoint)
QDate	Julian day (quint32)
QDateTime	Date ( QDate) Time ( QTime) 0 for Qt::LocalTime, 1 for Qt::UTC (quint8)
QFont	The family ( QString) The point size (qint16) The style hint (quint8) The char set (quint8) The weight (quint8) The font bits (quint8)
QHash<Key, T>	The number of items (quint32) For all items, the key (Key) and value (T)
QIcon	The number of pixmap entries (quint32) For all pixmap entries: The pixmap ( QPixmap) The file name ( QString) The pixmap size ( QSize) The mode (quint32) The state (quint32)
QImage	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.
QKeySequence	A QList<int>, where each integer is a key in the key sequence
QLinkedList<T>	The number of items (quint32) The items (T)
QList<T>	The number of items (quint32) The items (T)
QMap<Key, T>	The number of items (quint32) For all items, the key (Key) and value (T)
QMatrix	m11 (double) m12 (double) m21 (double) m22 (double) dx (double) dy (double)
QPair<T1, T2>	first (T1) second (T2)
QPalette	The disabled, active, and inactive color groups, each of which consists of the following: foreground ( QBrush) button ( QBrush) light ( QBrush) midlight ( QBrush) dark ( QBrush) mid ( QBrush) text ( QBrush) brightText ( QBrush) buttonText ( QBrush) base ( QBrush) background ( QBrush) shadow ( QBrush) highlight ( QBrush) highlightedText ( QBrush) link ( QBrush) linkVisited ( QBrush)
QPen	The pen styles (quint8) The pen width (quint16) The pen color ( QColor)
QPicture	The size of the picture data (quint32) The raw bytes of picture data (char)
QPixmap	Save it as a PNG image.
QPoint	The x coordinate (qint32) The y coordinate (qint32)
QRect	left (qint32) top (qint32) right (qint32) bottom (qint32)
QRegExp	The regexp pattern ( QString) Case sensitivity (quint8) Regular expression syntax (quint8) Minimal matching (quint8)
QRegion	The size of the data, i.e. 8 + 16 * (number of rectangles) (quint32) 10 (qint32) The number of rectangles (quint32) The rectangles in sequential order ( QRect)
QSize	width (qint32) height (qint32)
QString	If the string is null: 0xFFFFFFFF (quint32) Otherwise: The string length in bytes (quint32) followed by the data in UTF-16
QTime	Milliseconds since midnight (quint32)
QVariant	The type of the data (quint32) The null flag (qint8) The data of the specified type
QVector<T>	The number of items (quint32) The items (T)

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