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• sf
• Packet

Public Member Functions | Protected Member Functions | Friends | List of all members

sf::Packet Class Reference

Network module

Utility class to build blocks of data to transfer over the network. More...

#include <SFML/Network/Packet.hpp>

Public Member Functions
	Packet ()=default
	Default constructor.
virtual	~Packet ()=default
	Virtual destructor.
	Packet (const Packet &)=default
	Copy constructor.
Packet &	operator= (const Packet &)=default
	Copy assignment.
	Packet (Packet &&) noexcept=default
	Move constructor.
Packet &	operator= (Packet &&) noexcept=default
	Move assignment.
void	append (const void *data, std::size_t sizeInBytes)
	Append data to the end of the packet.
std::size_t	getReadPosition () const
	Get the current reading position in the packet.
void	clear ()
	Clear the packet.
const void *	getData () const
	Get a pointer to the data contained in the packet.
std::size_t	getDataSize () const
	Get the size of the data contained in the packet.
bool	endOfPacket () const
	Tell if the reading position has reached the end of the packet.
	operator bool () const
	Test the validity of the packet, for reading.
Packet &	operator>> (bool &data)
	Overload of operator>> to read data from the packet.
Packet &	operator>> (std::int8_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::uint8_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::int16_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::uint16_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::int32_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::uint32_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::int64_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::uint64_t &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (float &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (double &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (char *data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::string &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (wchar_t *data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (std::wstring &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator>> (String &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (bool data)
	Overload of operator<< to write data into the packet.
Packet &	operator<< (std::int8_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::uint8_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::int16_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::uint16_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::int32_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::uint32_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::int64_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (std::uint64_t data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (float data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (double data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (const char *data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (const std::string &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (const wchar_t *data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (const std::wstring &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Packet &	operator<< (const String &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Protected Member Functions
virtual const void *	onSend (std::size_t &size)
	Called before the packet is sent over the network.
virtual void	onReceive (const void *data, std::size_t size)
	Called after the packet is received over the network.

Friends
class	TcpSocket
class	UdpSocket

Detailed Description

Utility class to build blocks of data to transfer over the network.

Packets provide a safe and easy way to serialize data, in order to send it over the network using sockets (sf::TcpSocket, sf::UdpSocket).

Packets solve 2 fundamental problems that arise when transferring data over the network:

• data is interpreted correctly according to the endianness
• the bounds of the packet are preserved (one send == one receive)

The sf::Packet class provides both input and output modes. It is designed to follow the behavior of standard C++ streams, using operators >> and << to extract and insert data.

It is recommended to use only fixed-size types (like std::int32_t, etc.), to avoid possible differences between the sender and the receiver. Indeed, the native C++ types may have different sizes on two platforms and your data may be corrupted if that happens.

Usage example:

std::uint32_t x = 24;

std::string s = "hello";

double d = 5.89;

// Group the variables to send into a packet

sf::Packet packet;

packet << x << s << d;

// Send it over the network (socket is a valid sf::TcpSocket)

socket.send(packet);

-----------------------------------------------------------------

// Receive the packet at the other end

sf::Packet packet;

socket.receive(packet);

// Extract the variables contained in the packet

std::uint32_t x;

std::string s;

double d;

if (packet >> x >> s >> d)

{

// Data extracted successfully...

}

sf::Packet

Utility class to build blocks of data to transfer over the network.

Definition Packet.hpp:49

Packets have built-in operator>> and << overloads for standard types:

• bool
• fixed-size integer types (int[8|16|32]_t, uint[8|16|32]_t)
• floating point numbers (float, double)
• string types (char*, wchar_t*, std::string, std::wstring, sf::String)

Like standard streams, it is also possible to define your own overloads of operators >> and << in order to handle your custom types.

struct MyStruct

{

float number{};

std::int8_t integer{};

std::string str;

};

sf::Packet& operator <<(sf::Packet& packet, const MyStruct& m)

{

return packet << m.number << m.integer << m.str;

}

sf::Packet& operator >>(sf::Packet& packet, MyStruct& m)

{

return packet >> m.number >> m.integer >> m.str;

}

sf::Packet::operator>>

Packet & operator>>(bool &data)

Overload of operator>> to read data from the packet.

sf::Packet::operator<<

Packet & operator<<(bool data)

Overload of operator<< to write data into the packet.

Packets also provide an extra feature that allows to apply custom transformations to the data before it is sent, and after it is received. This is typically used to handle automatic compression or encryption of the data. This is achieved by inheriting from sf::Packet, and overriding the onSend and onReceive functions.

Here is an example:

class ZipPacket : public sf::Packet

{

const void* onSend(std::size_t& size) override

{

const void* srcData = getData();

std::size_t srcSize = getDataSize();

return MySuperZipFunction(srcData, srcSize, &size);

}

void onReceive(const void* data, std::size_t size) override

{

std::size_t dstSize;

const void* dstData = MySuperUnzipFunction(data, size, &dstSize);

append(dstData, dstSize);

}

};

// Use like regular packets:

ZipPacket packet;

packet << x << s << d;

...

sf::Packet::getDataSize

std::size_t getDataSize() const

Get the size of the data contained in the packet.

sf::Packet::append

void append(const void *data, std::size_t sizeInBytes)

Append data to the end of the packet.

sf::Packet::getData

const void * getData() const

Get a pointer to the data contained in the packet.

sf::Packet::onReceive

virtual void onReceive(const void *data, std::size_t size)

Called after the packet is received over the network.

sf::Packet::onSend

virtual const void * onSend(std::size_t &size)

Called before the packet is sent over the network.

See also

sf::TcpSocket, sf::UdpSocket

Definition at line 48 of file Packet.hpp.

Constructor & Destructor Documentation

◆ Packet() [1/3]

sf::Packet::Packet ( )

default

Default constructor.

Creates an empty packet.

◆ ~Packet()

virtual sf::Packet::~Packet ( )

virtualdefault

Virtual destructor.

◆ Packet() [2/3]

sf::Packet::Packet ( const Packet & )

default

Copy constructor.

◆ Packet() [3/3]

sf::Packet::Packet ( Packet && )

defaultnoexcept

Move constructor.

Member Function Documentation

◆ append()

void sf::Packet::append	(	const void *	data,
		std::size_t	sizeInBytes )

Append data to the end of the packet.

Parameters

data	Pointer to the sequence of bytes to append
sizeInBytes	Number of bytes to append

See also

clear

getReadPosition

◆ clear()

void sf::Packet::clear

(

)

Clear the packet.

After calling Clear, the packet is empty.

See also

append

◆ endOfPacket()

bool sf::Packet::endOfPacket ( ) const

nodiscard

Tell if the reading position has reached the end of the packet.

This function is useful to know if there is some data left to be read, without actually reading it.

Returns

true if all data was read, false otherwise

See also

operator bool

◆ getData()

const void * sf::Packet::getData ( ) const

nodiscard

Get a pointer to the data contained in the packet.

Warning: the returned pointer may become invalid after you append data to the packet, therefore it should never be stored. The return pointer is a nullptr if the packet is empty.

Returns

Pointer to the data

See also

getDataSize

◆ getDataSize()

std::size_t sf::Packet::getDataSize ( ) const

nodiscard

Get the size of the data contained in the packet.

This function returns the number of bytes pointed to by what getData returns.

Returns

Data size, in bytes

See also

getData

◆ getReadPosition()

std::size_t sf::Packet::getReadPosition ( ) const

nodiscard

Get the current reading position in the packet.

The next read operation will read data from this position

Returns

The byte offset of the current read position

See also

append

◆ onReceive()

virtual void sf::Packet::onReceive ( const void * data, std::size_t size )

protectedvirtual

Called after the packet is received over the network.

This function can be defined by derived classes to transform the data after it is received; this can be used for decompression, decryption, etc. The function receives a pointer to the received data, and must fill the packet with the transformed bytes. The default implementation fills the packet directly without transforming the data.

Parameters

data	Pointer to the received bytes
size	Number of bytes

See also

onSend

◆ onSend()

virtual const void * sf::Packet::onSend ( std::size_t & size )

protectedvirtual

Called before the packet is sent over the network.

This function can be defined by derived classes to transform the data before it is sent; this can be used for compression, encryption, etc. The function must return a pointer to the modified data, as well as the number of bytes pointed. The default implementation provides the packet's data without transforming it.

Parameters

size	Variable to fill with the size of data to send

Returns

Pointer to the array of bytes to send

See also

onReceive

◆ operator bool()

sf::Packet::operator bool ( ) const

explicit

Test the validity of the packet, for reading.

This operator allows to test the packet as a boolean variable, to check if a reading operation was successful.

A packet will be in an invalid state if it has no more data to read.

This behavior is the same as standard C++ streams.

Usage example:

float x;

packet >> x;

if (packet)

{

// ok, x was extracted successfully

}

// -- or --

float x;

if (packet >> x)

{

// ok, x was extracted successfully

}

Don't focus on the return type, it's equivalent to bool but it disallows unwanted implicit conversions to integer or pointer types.

Returns

true if last data extraction from packet was successful

See also

endOfPacket

◆ operator<<() [1/16]

Packet & sf::Packet::operator<<

(

bool

data

)

Overload of operator<< to write data into the packet.

◆ operator<<() [2/16]

Packet & sf::Packet::operator<<

(

const char *

data

)

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

◆ operator<<() [3/16]

Packet & sf::Packet::operator<<

(

const std::string &

data

)

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

◆ operator<<() [4/16]

Packet & sf::Packet::operator<<

(

const std::wstring &

data

)

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

◆ operator<<() [5/16]

Packet & sf::Packet::operator<<

(

const String &

data

)

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

◆ operator<<() [6/16]

Packet & sf::Packet::operator<<

(

const wchar_t *

data

)

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

◆ operator<<() [7/16]

Packet & sf::Packet::operator<<

(

double

data

)

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

◆ operator<<() [8/16]

Packet & sf::Packet::operator<<

(

float

data

)

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

◆ operator<<() [9/16]

Packet & sf::Packet::operator<<

(

std::int16_t

data

)

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

◆ operator<<() [10/16]

Packet & sf::Packet::operator<<

(

std::int32_t

data

)

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

◆ operator<<() [11/16]

Packet & sf::Packet::operator<<

(

std::int64_t

data

)

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

◆ operator<<() [12/16]

Packet & sf::Packet::operator<<

(

std::int8_t

data

)

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

◆ operator<<() [13/16]

Packet & sf::Packet::operator<<

(

std::uint16_t

data

)

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

◆ operator<<() [14/16]

Packet & sf::Packet::operator<<

(

std::uint32_t

data

)

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

◆ operator<<() [15/16]

Packet & sf::Packet::operator<<

(

std::uint64_t

data

)

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

◆ operator<<() [16/16]

Packet & sf::Packet::operator<<

(

std::uint8_t

data

)

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

◆ operator=() [1/2]

Packet & sf::Packet::operator= ( const Packet & )

default

Copy assignment.

◆ operator=() [2/2]

Packet & sf::Packet::operator= ( Packet && )

defaultnoexcept

Move assignment.

◆ operator>>() [1/16]

Packet & sf::Packet::operator>>

(

bool &

data

)

Overload of operator>> to read data from the packet.

◆ operator>>() [2/16]

Packet & sf::Packet::operator>>

(

char *

data

)

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

◆ operator>>() [3/16]

Packet & sf::Packet::operator>>

(

double &

data

)

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

◆ operator>>() [4/16]

Packet & sf::Packet::operator>>

(

float &

data

)

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

◆ operator>>() [5/16]

Packet & sf::Packet::operator>>

(

std::int16_t &

data

)

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

◆ operator>>() [6/16]

Packet & sf::Packet::operator>>

(

std::int32_t &

data

)

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

◆ operator>>() [7/16]

Packet & sf::Packet::operator>>

(

std::int64_t &

data

)

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

◆ operator>>() [8/16]

Packet & sf::Packet::operator>>

(

std::int8_t &

data

)

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

◆ operator>>() [9/16]

Packet & sf::Packet::operator>>

(

std::string &

data

)

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

◆ operator>>() [10/16]

Packet & sf::Packet::operator>>

(

std::uint16_t &

data

)

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

◆ operator>>() [11/16]

Packet & sf::Packet::operator>>

(

std::uint32_t &

data

)

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

◆ operator>>() [12/16]

Packet & sf::Packet::operator>>

(

std::uint64_t &

data

)

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

◆ operator>>() [13/16]

Packet & sf::Packet::operator>>

(

std::uint8_t &

data

)

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

◆ operator>>() [14/16]

Packet & sf::Packet::operator>>

(

std::wstring &

data

)

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

◆ operator>>() [15/16]

Packet & sf::Packet::operator>>

(

String &

data

)

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

◆ operator>>() [16/16]

Packet & sf::Packet::operator>>

(

wchar_t *

data

)

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

Friends And Related Symbol Documentation

◆ TcpSocket

friend class TcpSocket

friend

Definition at line 368 of file Packet.hpp.

◆ UdpSocket

friend class UdpSocket

friend

Definition at line 369 of file Packet.hpp.

---

The documentation for this class was generated from the following file:

• Packet.hpp