The QPacket class encapsulates an unfragmentable packet of data to be transmitted by QPacketProtocol. More...

#include <qpacket_p.h>

Inheritance diagram for QPacket:

Collaboration diagram for QPacket:

Public Member Functions
	QPacket (int version)
	Constructs an empty write-only packet.

	QPacket (int version, const QByteArray &ba)
	Constructs a read-only packet.

const QByteArray &	data () const
	Returns a reference to the raw packet data.

QByteArray	squeezedData () const
	Returns a copy of the raw packet data, with extra reserved space removed.

void	clear ()
	Clears the packet, discarding any data.

Public Member Functions inherited from QDataStream
enum Version	QT7_ONLY (:quint8)

enum Status	QT7_ONLY (:quint8)

enum FloatingPointPrecision	QT7_ONLY (:quint8)

	QDataStream ()
	Constructs a data stream that has no I/O device.

	QDataStream (QIODevice *)
	Constructs a data stream that uses the I/O device d.

	QDataStream (QByteArray *, OpenMode flags)
	Constructs a data stream that operates on a byte array, a.

	QDataStream (const QByteArray &)
	Constructs a read-only data stream that operates on byte array a.

	~QDataStream ()
	Destroys the data stream.

QIODevice *	device () const
	Returns the I/O device currently set, or \nullptr if no device is currently set.

void	setDevice (QIODevice *)
	void QDataStream::setDevice(QIODevice *d)

bool	atEnd () const
	Returns `true` if the I/O device has reached the end position (end of the stream or file) or if there is no I/O device set; otherwise returns `false`.

Status	status () const
	Returns the status of the data stream.

void	setStatus (Status status)
	Sets the status of the data stream to the status given.

void	resetStatus ()
	Resets the status of the data stream.

FloatingPointPrecision	floatingPointPrecision () const
	Returns the floating point precision of the data stream.

void	setFloatingPointPrecision (FloatingPointPrecision precision)
	Sets the floating point precision of the data stream to precision.

ByteOrder	byteOrder () const
	Returns the current byte order setting – either BigEndian or LittleEndian.

void	setByteOrder (ByteOrder)
	Sets the serialization byte order to bo.

int	version () const
	Returns the version number of the data serialization format.

void	setVersion (int)
	Sets the version number of the data serialization format to v, a value of the \l Version enum.

QDataStream &	operator>> (char &i)

QDataStream &	operator>> (qint8 &i)
	Reads a signed byte from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (quint8 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads an unsigned byte from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (qint16 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a signed 16-bit integer from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (quint16 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads an unsigned 16-bit integer from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (qint32 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a signed 32-bit integer from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (quint32 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads an unsigned 32-bit integer from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (qint64 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a signed 64-bit integer from the stream into i, and returns a reference to the stream.

QDataStream &	operator>> (quint64 &i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads an unsigned 64-bit integer from the stream, into i, and returns a reference to the stream.

QDataStream &	operator>> (std::nullptr_t &ptr)

QDataStream &	operator>> (bool &i)
	Reads a boolean value from the stream into i.

QDataStream &	operator>> (float &f)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a floating point number from the stream into f, using the standard IEEE 754 format.

QDataStream &	operator>> (double &f)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a floating point number from the stream into f, using the standard IEEE 754 format.

QDataStream &	operator>> (char *&str)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads string s from the stream and returns a reference to the stream.

QDataStream &	operator>> (char16_t &c)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QDataStream &	operator>> (char32_t &c)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QDataStream &	operator<< (char i)

QDataStream &	operator<< (qint8 i)
	Writes a signed byte, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (quint8 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes an unsigned byte, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (qint16 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes a signed 16-bit integer, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (quint16 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes an unsigned 16-bit integer, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (qint32 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes a signed 32-bit integer, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (quint32 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes an unsigned integer, i, to the stream as a 32-bit unsigned integer (quint32).

QDataStream &	operator<< (qint64 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes a signed 64-bit integer, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (quint64 i)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes an unsigned 64-bit integer, i, to the stream and returns a reference to the stream.

QDataStream &	operator<< (std::nullptr_t)

template<typename T , std::enable_if_t< std::is_same_v< T, bool >, bool > = true>
QDataStream &	operator<< (T i)

QDataStream &	operator<< (float f)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes a floating point number, f, to the stream using the standard IEEE 754 format.

QDataStream &	operator<< (double f)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes a floating point number, f, to the stream using the standard IEEE 754 format.

QDataStream &	operator<< (const char *str)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes the '\0'-terminated string s to the stream and returns a reference to the stream.

QDataStream &	operator<< (char16_t c)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QDataStream &	operator<< (char32_t c)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QDataStream &	readBytes (char *&, qint64 &len)

qint64	readRawData (char *, qint64 len)
	Reads at most len bytes from the stream into s and returns the number of bytes read.

QDataStream &	writeBytes (const char *, qint64 len)
	Writes the length specifier len and the buffer s to the stream and returns a reference to the stream.

qint64	writeRawData (const char *, qint64 len)
	Writes len bytes from s to the stream.

qint64	skipRawData (qint64 len)

void	startTransaction ()

bool	commitTransaction ()

void	rollbackTransaction ()

void	abortTransaction ()

bool	isDeviceTransactionStarted () const

Additional Inherited Members
Public Types inherited from QDataStream
enum	ByteOrder { BigEndian = QSysInfo::BigEndian , LittleEndian = QSysInfo::LittleEndian }
	The byte order used for reading/writing the data. More...

Public Types inherited from QIODeviceBase
enum	OpenModeFlag { NotOpen = 0x0000 , ReadOnly = 0x0001 , WriteOnly = 0x0002 , ReadWrite = ReadOnly \| WriteOnly , Append = 0x0004 , Truncate = 0x0008 , Text = 0x0010 , Unbuffered = 0x0020 , NewOnly = 0x0040 , ExistingOnly = 0x0080 }
	This enum is used with QIODevice::open() to describe the mode in which a device is opened. More...

Protected Member Functions inherited from QIODeviceBase
	~QIODeviceBase ()=default

Related Symbols inherited from QDataStream
	operator<< (QDataStream &ds, qfloat16 f)

	operator>> (QDataStream &ds, qfloat16 &f)

template< class T1, class T2 > QDataStream &	operator>> (QDataStream &in, std::pair< T1, T2 > &pair)

template< class T1, class T2 > QDataStream &	operator<< (QDataStream &out, const std::pair< T1, T2 > &pair)

Detailed Description

The QPacket class encapsulates an unfragmentable packet of data to be transmitted by QPacketProtocol.

The QPacket class works together with QPacketProtocol to make it simple to send arbitrary sized data "packets" across fragmented transports such as TCP and UDP.

QPacket provides a QDataStream interface to an unfragmentable packet. Applications should construct a QPacket, propagate it with data and then transmit it over a QPacketProtocol instance. For example:

int version = QDataStream::Qt_DefaultCompiledVersion;
QPacketProtocol protocol(...);
 
QPacket myPacket(version);
myPacket << "Hello world!" << 123;
protocol.send(myPacket.data());

As long as both ends of the connection are using the QPacketProtocol class and the same data stream version, the data within this packet will be delivered unfragmented at the other end, ready for extraction.

QByteArray greeting;
int count;
 
QPacket myPacket(version, protocol.read());
 
myPacket >> greeting >> count;

Only packets constructed from raw byte arrays may be read from. Empty QPacket instances are for transmission only and are considered "write only". Attempting to read data from them will result in undefined behavior.