automatically resized byte buffer More...

#include "buffer.h"

Classes
struct	Data
	This data structure is variable-sized through its last member whose size is determined at allocation time and stored in the m_size field. More...

class	Iterator
	iterator in a Buffer instance More...

struct	LocalStaticDestructor
	Local static destructor structure. More...

Public Member Functions
	Buffer (Buffer const &o)
	Copy constructor. More...

	Buffer ()

	Buffer (uint32_t dataSize)
	Constructor. More...

	Buffer (uint32_t dataSize, bool initialize)
	Constructor. More...

	~Buffer ()

void	AddAtEnd (uint32_t end)

void	AddAtEnd (const Buffer &o)

void	AddAtStart (uint32_t start)

Buffer::Iterator	Begin (void) const

void	CopyData (std::ostream *os, uint32_t size) const
	Copy the specified amount of data from the buffer to the given output stream. More...

uint32_t	CopyData (uint8_t *buffer, uint32_t size) const
	Copy the specified amount of data from the buffer to the given buffer. More...

Buffer	CreateFragment (uint32_t start, uint32_t length) const

uint32_t	Deserialize (const uint8_t *buffer, uint32_t size)

Buffer::Iterator	End (void) const

uint32_t	GetSerializedSize (void) const
	Return the number of bytes required for serialization. More...

uint32_t	GetSize (void) const

Buffer &	operator= (Buffer const &o)
	Assignment operator. More...

uint8_t const *	PeekData (void) const

void	RemoveAtEnd (uint32_t end)

void	RemoveAtStart (uint32_t start)

uint32_t	Serialize (uint8_t *buffer, uint32_t maxSize) const

Private Types
typedef std::vector< struct Buffer::Data * >	FreeList
	Container for buffer data. More...

Private Member Functions
bool	CheckInternalState (void) const
	Checks the internal buffer structures consistency. More...

Buffer	CreateFullCopy (void) const
	Create a full copy of the buffer, including all the internal structures. More...

uint32_t	GetInternalEnd (void) const
	Get the buffer end position. More...

uint32_t	GetInternalSize (void) const
	Get the buffer real size. More...

void	Initialize (uint32_t zeroSize)
	Initializes the buffer with a number of zeroes. More...

void	TransformIntoRealBuffer (void) const
	Transform a "Virtual byte buffer" into a "Real byte buffer". More...

Static Private Member Functions
static struct Buffer::Data *	Allocate (uint32_t reqSize)
	Allocate a buffer data storage. More...

static struct Buffer::Data *	Create (uint32_t size)
	Create a buffer data storage. More...

static void	Deallocate (struct Buffer::Data *data)
	Deallocate the buffer memory. More...

static void	Recycle (struct Buffer::Data *data)
	Recycle the buffer memory. More...

Private Attributes
struct Data *	m_data
	the buffer data storage More...

uint32_t	m_end
	offset to the end of the data referenced by this Buffer instance from the start of m_data->m_data More...

uint32_t	m_maxZeroAreaStart
	keep track of the maximum value of m_zeroAreaStart across the lifetime of a Buffer instance. More...

uint32_t	m_start
	offset to the start of the data referenced by this Buffer instance from the start of m_data->m_data More...

uint32_t	m_zeroAreaEnd
	offset to the end of the virtual zero area from the start of m_data->m_data More...

uint32_t	m_zeroAreaStart
	offset to the start of the virtual zero area from the start of m_data->m_data More...

Static Private Attributes
static FreeList *	g_freeList = 0
	Buffer data container. More...

static struct LocalStaticDestructor	g_localStaticDestructor
	Local static destructor. More...

static uint32_t	g_maxSize = 0
	Max observed data size. More...

static uint32_t	g_recommendedStart = 0
	location in a newly-allocated buffer where you should start writing data. More...

Detailed Description

automatically resized byte buffer

This represents a buffer of bytes. Its size is automatically adjusted to hold any data prepended or appended by the user. Its implementation is optimized to ensure that the number of buffer resizes is minimized, by creating new Buffers of the maximum size ever used. The correct maximum size is learned at runtime during use by recording the maximum size of each packet.

Internal:: The implementation of the Buffer class uses a COW (Copy On Write) technique to ensure that the underlying data buffer which holds the data bytes is shared among a lot of Buffer instances despite data being added or removed from them.

When multiple Buffer instances hold a reference to the same underlying BufferData object, they must be able to detect when the operation they want to perform should trigger a copy of the BufferData. If the BufferData::m_count field is one, it means that there exist only one instance of Buffer which references the BufferData instance so, it is safe to modify it. It is also safe to modify the content of a BufferData if the modification falls outside of the "dirty area" defined by the BufferData. In every other case, the BufferData must be copied before being modified.

To understand the way the Buffer::Add and Buffer::Remove methods work, you first need to understand the "virtual offsets" used to keep track of the content of buffers. Each Buffer instance contains real data bytes in its BufferData instance but it also contains "virtual zero data" which typically is used to represent application-level payload. No memory is allocated to store the zero bytes of application-level payload unless the user fragments a Buffer: this application-level payload is kept track of with a pair of integers which describe where in the buffer content the "virtual zero area" starts and ends.

* ***: unused bytes
* xxx: bytes "added" at the front of the zero area
* ...: bytes "added" at the back of the zero area
* 000: virtual zero bytes
*
* Real byte buffer:      |********xxxxxxxxxxxx.........*****|
*                        |--------^ m_start
*                        |-------------------^ m_zeroAreaStart
*                        |-----------------------------^ m_end - (m_zeroAreaEnd - m_zeroAreaStart)
* Virtual byte buffer:           |xxxxxxxxxxxx0000000000000.........|
*                        |--------^ m_start
*                        |--------------------^ m_zeroAreaStart
*                        |---------------------------------^ m_zeroAreaEnd
*                        |------------------------------------------^ m_end
*

A simple state invariant is that m_start <= m_zeroStart <= m_zeroEnd <= m_end

Definition at line 92 of file buffer.h.

Member Typedef Documentation

◆ FreeList

typedef std::vector<struct Buffer::Data*> ns3::Buffer::FreeList

private

Container for buffer data.

Definition at line 795 of file buffer.h.

Constructor & Destructor Documentation

◆ Buffer() [1/4]

ns3::Buffer::Buffer ( Buffer const & o )

inline

Copy constructor.

Parameters

o	the buffer to copy

Definition at line 1050 of file buffer.h.

References CheckInternalState(), ns3::Buffer::Data::m_count, m_data, and NS_ASSERT.

◆ Buffer() [2/4]

ns3::Buffer::Buffer ( )

Definition at line 188 of file buffer.cc.

References Initialize(), and NS_LOG_FUNCTION.

◆ Buffer() [3/4]

ns3::Buffer::Buffer ( uint32_t dataSize )

Constructor.

The buffer will be initialized with zeroes up to its size.

Parameters

dataSize the buffer size

Definition at line 194 of file buffer.cc.

References Initialize(), and NS_LOG_FUNCTION.

◆ Buffer() [4/4]

ns3::Buffer::Buffer	(	uint32_t	dataSize,
		bool	initialize
	)

Constructor.

If initialize is set to true, the buffer will be initialized with zeroes up to its size.

Parameters

dataSize	the buffer size.
initialize	initialize the buffer with zeroes.

Definition at line 200 of file buffer.cc.

References Initialize(), and NS_LOG_FUNCTION.

◆ ~Buffer()

ns3::Buffer::~Buffer ( )

Definition at line 283 of file buffer.cc.

References CheckInternalState(), g_recommendedStart, ns3::Buffer::Data::m_count, m_data, m_maxZeroAreaStart, max, NS_ASSERT, NS_LOG_FUNCTION, and Recycle().

Member Function Documentation

◆ AddAtEnd() [1/2]

void ns3::Buffer::AddAtEnd ( uint32_t end )

Parameters

end	size to reserve

Add bytes at the end of the Buffer. The content of these bytes is undefined but debugging builds initialize them to 0x33. Any call to this method invalidates any Iterator pointing to this Buffer.

Definition at line 354 of file buffer.cc.

References CheckInternalState(), Create(), GetInternalEnd(), GetInternalSize(), LOG_INTERNAL_STATE, ns3::Buffer::Data::m_count, ns3::Buffer::Data::m_data, m_data, ns3::Buffer::Data::m_dirtyEnd, ns3::Buffer::Data::m_dirtyStart, m_end, m_maxZeroAreaStart, m_start, m_zeroAreaEnd, m_zeroAreaStart, max, NS_ASSERT, NS_LOG_FUNCTION, and Recycle().

Referenced by ns3::Packet::AddAtEnd(), AddAtEnd(), ns3::dsr::DsrOptionField::AddDsrOption(), ns3::OptionField::AddOption(), ns3::Packet::AddPaddingAtEnd(), ns3::Packet::AddTrailer(), CreateFullCopy(), ns3::Ipv6ExtensionHeader::Deserialize(), ns3::dsr::DsrOptionHeader::Deserialize(), ns3::Ipv6OptionHeader::Deserialize(), ns3::dsr::DsrFsHeader::Deserialize(), ns3::OptionField::Deserialize(), ns3::dsr::DsrOptionField::Deserialize(), Deserialize(), ns3::dsr::DsrOptionRerrHeader::Deserialize(), BufferTest::DoRun(), ns3::WifiInformationElement::operator==(), and ns3::Asn1Header::WriteOctet().

◆ AddAtEnd() [2/2]

void ns3::Buffer::AddAtEnd ( const Buffer & o )

Parameters

o	the buffer to append to the end of this buffer.

Add bytes at the end of the Buffer. Any call to this method invalidates any Iterator pointing to this Buffer.

This is an optimization which kicks in when we attempt to aggregate two buffers which contain adjacent zero areas.

Definition at line 400 of file buffer.cc.

References AddAtEnd(), Begin(), CheckInternalState(), CreateFullCopy(), End(), GetSize(), ns3::Buffer::Data::m_count, m_data, ns3::Buffer::Data::m_dirtyEnd, m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, NS_ASSERT, NS_LOG_FUNCTION, ns3::Buffer::Iterator::Prev(), and ns3::Buffer::Iterator::Write().

◆ AddAtStart()

void ns3::Buffer::AddAtStart ( uint32_t start )

Parameters

start size to reserve

Add bytes at the start of the Buffer. The content of these bytes is undefined but debugging builds initialize them to 0x33. Any call to this method invalidates any Iterator pointing to this Buffer.

Definition at line 309 of file buffer.cc.

References CheckInternalState(), Create(), GetInternalSize(), LOG_INTERNAL_STATE, ns3::Buffer::Data::m_count, ns3::Buffer::Data::m_data, m_data, ns3::Buffer::Data::m_dirtyEnd, ns3::Buffer::Data::m_dirtyStart, m_end, m_maxZeroAreaStart, m_start, m_zeroAreaEnd, m_zeroAreaStart, max, NS_ASSERT, NS_LOG_FUNCTION, Recycle(), and visualizer.core::start().

Referenced by ns3::Packet::AddHeader(), ns3::UdpHeader::CalculateHeaderChecksum(), ns3::TcpHeader::CalculateHeaderChecksum(), ns3::Icmpv6Header::CalculatePseudoHeaderChecksum(), TcpHeaderWithRFC793OptionTestCase::CheckCorrectDeserialize(), TcpHeaderWithRFC793OptionTestCase::CheckNoPadding(), ns3::SixLowPanNetDevice::CompressLowPanNhc(), CreateFullCopy(), ns3::SixLowPanNetDevice::DecompressLowPanNhc(), Deserialize(), ns3::PbbTlv::Deserialize(), TestEmptyOptionField::DoRun(), BufferTest::DoRun(), TcpHeaderGetSetTestCase::DoRun(), DsrFsHeaderTest::DoRun(), TestOptionWithoutAlignment::DoRun(), TestOptionWithAlignment::DoRun(), TestFulfilledAlignment::DoRun(), TcpHeaderWithRFC793OptionTestCase::OneOptionAtTime(), ns3::Packet::Packet(), PbbTestCase::PbbTestCase(), ns3::Ipv6ExtensionLooseRouting::Process(), ns3::PbbTlv::SetValue(), TcpOptionWSTestCase::TestSerialize(), PbbTestCase::TestSerialize(), TcpOptionTSTestCase::TestSerialize(), and ns3::PcapFile::Write().

◆ Allocate()

struct Buffer::Data * ns3::Buffer::Allocate ( uint32_t reqSize )

staticprivate

Allocate a buffer data storage.

Parameters

reqSize the storage size to create

Returns: a pointer to the allocated buffer storage

Definition at line 163 of file buffer.cc.

References data, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by Create().

◆ Begin()

Buffer::Iterator ns3::Buffer::Begin ( void ) const

inline

Returns: an Iterator which points to the start of this Buffer.

Definition at line 1069 of file buffer.h.

References CheckInternalState(), and NS_ASSERT.

Referenced by AddAtEnd(), ns3::Packet::AddHeader(), ns3::UdpHeader::CalculateHeaderChecksum(), ns3::TcpHeader::CalculateHeaderChecksum(), ns3::Icmpv6Header::CalculatePseudoHeaderChecksum(), TcpHeaderWithRFC793OptionTestCase::CheckCorrectDeserialize(), TcpHeaderWithRFC793OptionTestCase::CheckNoPadding(), ns3::SixLowPanNetDevice::CompressLowPanNhc(), CreateFullCopy(), ns3::SixLowPanNetDevice::DecompressLowPanNhc(), ns3::Ipv6ExtensionHeader::Deserialize(), ns3::dsr::DsrOptionHeader::Deserialize(), ns3::Ipv6OptionHeader::Deserialize(), ns3::dsr::DsrFsHeader::Deserialize(), ns3::OptionField::Deserialize(), ns3::dsr::DsrOptionField::Deserialize(), Deserialize(), ns3::dsr::DsrOptionRerrHeader::Deserialize(), ns3::PbbTlv::Deserialize(), BufferTest::DoRun(), TcpHeaderGetSetTestCase::DoRun(), TcpHeaderWithRFC793OptionTestCase::OneOptionAtTime(), ns3::WifiInformationElement::operator==(), ns3::Packet::Packet(), PbbTestCase::PbbTestCase(), ns3::Packet::PeekHeader(), ns3::Ipv6ExtensionLooseRouting::Process(), ns3::Packet::RemoveHeader(), ns3::Asn1Header::Serialize(), ns3::dsr::DsrOptionHeader::Serialize(), ns3::Ipv6OptionHeader::Serialize(), ns3::OptionField::Serialize(), ns3::dsr::DsrOptionField::Serialize(), ns3::dsr::DsrOptionRerrHeader::Serialize(), ns3::PbbTlv::SetValue(), TcpOptionWSTestCase::TestDeserialize(), PbbTestCase::TestDeserialize(), TcpOptionTSTestCase::TestDeserialize(), TcpOptionWSTestCase::TestSerialize(), PbbTestCase::TestSerialize(), TcpOptionTSTestCase::TestSerialize(), and ns3::PcapFile::Write().

◆ CheckInternalState()

bool ns3::Buffer::CheckInternalState ( void ) const

private

Checks the internal buffer structures consistency.

Used only for debugging purposes.

Returns: true if the buffer status is consistent.

Definition at line 210 of file buffer.cc.

References ns3::if(), LOG_INTERNAL_STATE, ns3::Buffer::Data::m_count, m_data, ns3::Buffer::Data::m_dirtyEnd, ns3::Buffer::Data::m_dirtyStart, m_end, ns3::Buffer::Data::m_size, m_start, m_zeroAreaEnd, m_zeroAreaStart, and NS_LOG_FUNCTION.

Referenced by AddAtEnd(), AddAtStart(), Begin(), Buffer(), CreateFragment(), CreateFullCopy(), End(), Initialize(), operator=(), PeekData(), RemoveAtEnd(), RemoveAtStart(), TransformIntoRealBuffer(), and ~Buffer().

◆ CopyData() [1/2]

void ns3::Buffer::CopyData	(	std::ostream *	os,
		uint32_t	size
	)		const

Copy the specified amount of data from the buffer to the given output stream.

Parameters

os	the output stream
size	the maximum amount of bytes to copy. If zero, nothing is copied.

Definition at line 715 of file buffer.cc.

References anonymous_namespace{buffer.cc}::Zeroes::buffer, anonymous_namespace{buffer.cc}::g_zeroes, ns3::Buffer::Data::m_data, m_data, m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, min, NS_LOG_FUNCTION, and anonymous_namespace{buffer.cc}::Zeroes::size.

Referenced by ns3::Packet::CopyData(), and ns3::PcapFile::Write().

◆ CopyData() [2/2]

uint32_t ns3::Buffer::CopyData	(	uint8_t *	buffer,
		uint32_t	size
	)		const

Copy the specified amount of data from the buffer to the given buffer.

Parameters

buffer	the output buffer
size	the maximum amount of bytes to copy. If zero, nothing is copied.

Returns: the amount of bytes copied

Definition at line 744 of file buffer.cc.

References anonymous_namespace{buffer.cc}::Zeroes::buffer, anonymous_namespace{buffer.cc}::g_zeroes, ns3::Buffer::Data::m_data, m_data, m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, min, NS_LOG_FUNCTION, and anonymous_namespace{buffer.cc}::Zeroes::size.

◆ Create()

Buffer::Data * ns3::Buffer::Create ( uint32_t size )

staticprivate

Create a buffer data storage.

Parameters

size	the storage size to create

Returns: a pointer to the created buffer storage

Definition at line 119 of file buffer.cc.

References Allocate(), data, Deallocate(), g_freeList, IS_INITIALIZED, IS_UNINITIALIZED, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by AddAtEnd(), AddAtStart(), and Initialize().

◆ CreateFragment()

Buffer ns3::Buffer::CreateFragment	(	uint32_t	start,
		uint32_t	length
	)		const

Parameters

start	offset from start of packet
length

Returns: a fragment of size length starting at offset start.

Definition at line 519 of file buffer.cc.

References CheckInternalState(), GetSize(), NS_ASSERT, NS_LOG_FUNCTION, RemoveAtEnd(), RemoveAtStart(), and visualizer.core::start().

Referenced by ns3::Packet::CreateFragment(), and BufferTest::DoRun().

◆ CreateFullCopy()

Buffer ns3::Buffer::CreateFullCopy ( void ) const

private

Create a full copy of the buffer, including all the internal structures.

Returns: a copy of the buffer

Definition at line 531 of file buffer.cc.

References AddAtEnd(), AddAtStart(), Begin(), CheckInternalState(), End(), ns3::Buffer::Data::m_data, m_data, m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, NS_ASSERT, NS_LOG_FUNCTION, ns3::Buffer::Iterator::Prev(), ns3::Buffer::Iterator::Write(), and ns3::Buffer::Iterator::WriteU8().

Referenced by AddAtEnd(), and TransformIntoRealBuffer().

◆ Deallocate()

void ns3::Buffer::Deallocate ( struct Buffer::Data * data )

staticprivate

Deallocate the buffer memory.

Parameters

data	the buffer data storage

Definition at line 180 of file buffer.cc.

References data, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by Create(), Recycle(), and ns3::Buffer::LocalStaticDestructor::~LocalStaticDestructor().

◆ Deserialize()

uint32_t ns3::Buffer::Deserialize	(	const uint8_t *	buffer,
		uint32_t	size
	)

Returns: zero if a complete buffer is not deserialized

Parameters

buffer	points to buffer for deserialization
size	number of bytes to deserialize

The raw character buffer is deserialized and all the data is placed into this buffer.

Definition at line 648 of file buffer.cc.

References AddAtEnd(), AddAtStart(), Begin(), End(), Initialize(), NS_ASSERT, NS_LOG_FUNCTION, ns3::Buffer::Iterator::Prev(), and ns3::Buffer::Iterator::Write().

Referenced by ns3::Packet::Deserialize().

◆ End()

Buffer::Iterator ns3::Buffer::End ( void ) const

inline

Returns: an Iterator which points to the end of this Buffer.

Definition at line 1075 of file buffer.h.

References CheckInternalState(), and NS_ASSERT.

Referenced by AddAtEnd(), ns3::dsr::DsrOptionField::AddDsrOption(), ns3::OptionField::AddOption(), ns3::Packet::AddTrailer(), CreateFullCopy(), Deserialize(), BufferTest::DoRun(), ns3::Packet::PeekTrailer(), ns3::Packet::RemoveTrailer(), ns3::Asn1Header::Serialize(), ns3::dsr::DsrOptionHeader::Serialize(), ns3::Ipv6OptionHeader::Serialize(), ns3::OptionField::Serialize(), ns3::dsr::DsrOptionField::Serialize(), ns3::dsr::DsrOptionRerrHeader::Serialize(), and ns3::Asn1Header::WriteOctet().

◆ GetInternalEnd()

uint32_t ns3::Buffer::GetInternalEnd ( void ) const

private

Get the buffer end position.

Returns: the buffer end index.

Definition at line 302 of file buffer.cc.

References m_end, m_zeroAreaEnd, m_zeroAreaStart, and NS_LOG_FUNCTION.

Referenced by AddAtEnd().

◆ GetInternalSize()

uint32_t ns3::Buffer::GetInternalSize ( void ) const

private

Get the buffer real size.

Warning: The real size is the actual memory used by the buffer.

Returns: the memory used by the buffer.

Definition at line 296 of file buffer.cc.

References m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, and NS_LOG_FUNCTION.

Referenced by AddAtEnd(), and AddAtStart().

◆ GetSerializedSize()

uint32_t ns3::Buffer::GetSerializedSize ( void ) const

Return the number of bytes required for serialization.

Returns: the number of bytes.

Definition at line 556 of file buffer.cc.

References m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, and NS_LOG_FUNCTION.

Referenced by ns3::Packet::GetSerializedSize(), and ns3::Packet::Serialize().

◆ GetSize()

uint32_t ns3::Buffer::GetSize ( void ) const

inline

Returns: the number of bytes stored in this buffer.

Definition at line 1063 of file buffer.h.

References m_end, and m_start.

Referenced by AddAtEnd(), ns3::OptionField::CalculatePad(), ns3::dsr::DsrOptionField::CalculatePad(), TcpHeaderWithRFC793OptionTestCase::CheckNoPadding(), ns3::SixLowPanNetDevice::CompressLowPanNhc(), ns3::Packet::CreateFragment(), CreateFragment(), ns3::Ipv6ExtensionHeader::Deserialize(), ns3::dsr::DsrFsHeader::Deserialize(), BufferTest::DoRun(), ns3::Asn1Header::GetSerializedSize(), ns3::OptionField::GetSerializedSize(), ns3::dsr::DsrOptionField::GetSerializedSize(), ns3::PbbTlv::GetSerializedSize(), ns3::Packet::GetSize(), TcpHeaderWithRFC793OptionTestCase::OneOptionAtTime(), ns3::PbbTlv::operator==(), ns3::PbbTlv::Print(), ns3::Ipv6ExtensionHeader::Serialize(), ns3::dsr::DsrFsHeader::Serialize(), ns3::PbbTlv::Serialize(), PbbTestCase::TestDeserialize(), PbbTestCase::TestSerialize(), and ns3::PbbTlv::~PbbTlv().

◆ Initialize()

void ns3::Buffer::Initialize ( uint32_t zeroSize )

private

Initializes the buffer with a number of zeroes.

Parameters

zeroSize the zeroes size

Definition at line 244 of file buffer.cc.

References CheckInternalState(), Create(), g_recommendedStart, m_data, ns3::Buffer::Data::m_dirtyEnd, ns3::Buffer::Data::m_dirtyStart, m_end, m_maxZeroAreaStart, ns3::Buffer::Data::m_size, m_start, m_zeroAreaEnd, m_zeroAreaStart, min, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by Buffer(), and Deserialize().

◆ operator=()

Buffer & ns3::Buffer::operator= ( Buffer const & o )

Assignment operator.

Parameters

o	the buffer to copy

Returns: a reference to the buffer

Definition at line 259 of file buffer.cc.

References CheckInternalState(), g_recommendedStart, ns3::Buffer::Data::m_count, m_data, m_end, m_maxZeroAreaStart, m_start, m_zeroAreaEnd, m_zeroAreaStart, max, NS_ASSERT, and Recycle().

◆ PeekData()

uint8_t const * ns3::Buffer::PeekData ( void ) const

Returns: a pointer to the start of the internal byte buffer.

The returned pointer points to an area of memory which is ns3::Buffer::GetSize () bytes big. Please, try to never ever use this method. It is really evil and is present only for a few specific uses.

Definition at line 705 of file buffer.cc.

References CheckInternalState(), ns3::Buffer::Data::m_data, m_data, m_start, NS_ASSERT, NS_LOG_FUNCTION, and TransformIntoRealBuffer().

Referenced by ns3::SixLowPanNetDevice::CompressLowPanNhc(), BufferTest::DoRun(), BufferTest::EnsureWrittenBytes(), ns3::WifiInformationElement::operator==(), ns3::PbbTlv::operator==(), ns3::Ipv6ExtensionHeader::Serialize(), ns3::dsr::DsrFsHeader::Serialize(), and PbbTestCase::TestSerialize().

◆ Recycle()

void ns3::Buffer::Recycle ( struct Buffer::Data * data )

staticprivate

Recycle the buffer memory.

Parameters

data	the buffer data storage

Definition at line 98 of file buffer.cc.

References data, Deallocate(), g_freeList, g_maxSize, IS_DESTROYED, IS_INITIALIZED, IS_UNINITIALIZED, max, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by AddAtEnd(), AddAtStart(), operator=(), and ~Buffer().

◆ RemoveAtEnd()

void ns3::Buffer::RemoveAtEnd ( uint32_t end )

Parameters

end	size to remove

Remove bytes at the end of the Buffer. Any call to this method invalidates any Iterator pointing to this Buffer.

Definition at line 483 of file buffer.cc.

References CheckInternalState(), LOG_INTERNAL_STATE, m_end, m_maxZeroAreaStart, m_start, m_zeroAreaEnd, m_zeroAreaStart, max, min, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by CreateFragment(), ns3::Ipv6ExtensionHeader::Deserialize(), ns3::dsr::DsrFsHeader::Deserialize(), BufferTest::DoRun(), ns3::Packet::RemoveAtEnd(), ns3::Packet::RemoveTrailer(), and ns3::PbbTlv::~PbbTlv().

◆ RemoveAtStart()

void ns3::Buffer::RemoveAtStart ( uint32_t start )

Parameters

start size to remove

Remove bytes at the start of the Buffer. Any call to this method invalidates any Iterator pointing to this Buffer.

Definition at line 438 of file buffer.cc.

References CheckInternalState(), LOG_INTERNAL_STATE, m_end, m_maxZeroAreaStart, m_start, m_zeroAreaEnd, m_zeroAreaStart, max, NS_ASSERT, NS_LOG_FUNCTION, and visualizer.core::start().

Referenced by ns3::SixLowPanNetDevice::CompressLowPanNhc(), CreateFragment(), BufferTest::DoRun(), ns3::Packet::RemoveAtStart(), and ns3::Packet::RemoveHeader().

◆ Serialize()

uint32_t ns3::Buffer::Serialize	(	uint8_t *	buffer,
		uint32_t	maxSize
	)		const

Returns: zero if buffer not large enough

Parameters

buffer	points to serialization buffer
maxSize	max number of bytes to write

This buffer's contents are serialized into the raw character buffer parameter. Note: The zero length data is not copied entirely. Only the length of zero byte data is serialized.

Definition at line 576 of file buffer.cc.

References ns3::Buffer::Data::m_data, m_data, m_end, m_start, m_zeroAreaEnd, m_zeroAreaStart, and NS_LOG_FUNCTION.

Referenced by ns3::Packet::Serialize().

◆ TransformIntoRealBuffer()

void ns3::Buffer::TransformIntoRealBuffer ( void ) const

private

Transform a "Virtual byte buffer" into a "Real byte buffer".

Definition at line 694 of file buffer.cc.

References CheckInternalState(), CreateFullCopy(), NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by PeekData().

Member Data Documentation

◆ g_freeList

Buffer::FreeList * ns3::Buffer::g_freeList = 0

staticprivate

Buffer data container.

Definition at line 802 of file buffer.h.

Referenced by Create(), Recycle(), and ns3::Buffer::LocalStaticDestructor::~LocalStaticDestructor().

◆ g_localStaticDestructor

struct LocalStaticDestructor ns3::Buffer::g_localStaticDestructor

staticprivate

Local static destructor.

Definition at line 803 of file buffer.h.

◆ g_maxSize

uint32_t ns3::Buffer::g_maxSize = 0

staticprivate

Max observed data size.

Definition at line 801 of file buffer.h.

Referenced by Recycle().

◆ g_recommendedStart

uint32_t ns3::Buffer::g_recommendedStart = 0

staticprivate

location in a newly-allocated buffer where you should start writing data.

i.e., m_start should be initialized to this value.

Definition at line 770 of file buffer.h.

Referenced by Initialize(), operator=(), and ~Buffer().

◆ m_data

struct Data* ns3::Buffer::m_data

private

the buffer data storage

Definition at line 752 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), Buffer(), CheckInternalState(), ns3::Buffer::Iterator::Construct(), CopyData(), CreateFullCopy(), Initialize(), operator=(), PeekData(), ns3::Buffer::Iterator::PeekU8(), ns3::Buffer::Iterator::ReadNtohU16(), ns3::Buffer::Iterator::ReadNtohU32(), Serialize(), ns3::Buffer::Iterator::Write(), ns3::Buffer::Iterator::WriteHtonU16(), ns3::Buffer::Iterator::WriteHtonU32(), ns3::Buffer::Iterator::WriteU8(), and ~Buffer().

◆ m_end

uint32_t ns3::Buffer::m_end

private

offset to the end of the data referenced by this Buffer instance from the start of m_data->m_data

Definition at line 791 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), CheckInternalState(), ns3::Buffer::Iterator::Construct(), CopyData(), CreateFullCopy(), GetInternalEnd(), GetInternalSize(), GetSerializedSize(), GetSize(), Initialize(), operator=(), RemoveAtEnd(), RemoveAtStart(), and Serialize().

◆ m_maxZeroAreaStart

uint32_t ns3::Buffer::m_maxZeroAreaStart

private

keep track of the maximum value of m_zeroAreaStart across the lifetime of a Buffer instance.

This variable is used purely as a source of information for the heuristics which decide on the position of the zero area in new buffers. It is read from the Buffer destructor to update the global heuristic data and these global heuristic data are used from the Buffer constructor to choose an initial value for m_zeroAreaStart.

Definition at line 764 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), Initialize(), operator=(), RemoveAtEnd(), RemoveAtStart(), and ~Buffer().

◆ m_start

uint32_t ns3::Buffer::m_start

private

offset to the start of the data referenced by this Buffer instance from the start of m_data->m_data

Definition at line 786 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), CheckInternalState(), ns3::Buffer::Iterator::Construct(), CopyData(), CreateFullCopy(), GetInternalSize(), GetSerializedSize(), GetSize(), Initialize(), operator=(), PeekData(), RemoveAtEnd(), RemoveAtStart(), and Serialize().

◆ m_zeroAreaEnd

uint32_t ns3::Buffer::m_zeroAreaEnd

private

offset to the end of the virtual zero area from the start of m_data->m_data

Definition at line 781 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), CheckInternalState(), ns3::Buffer::Iterator::Construct(), CopyData(), CreateFullCopy(), GetInternalEnd(), GetInternalSize(), GetSerializedSize(), Initialize(), operator=(), RemoveAtEnd(), RemoveAtStart(), and Serialize().

◆ m_zeroAreaStart

uint32_t ns3::Buffer::m_zeroAreaStart

private

offset to the start of the virtual zero area from the start of m_data->m_data

Definition at line 776 of file buffer.h.

Referenced by AddAtEnd(), AddAtStart(), CheckInternalState(), ns3::Buffer::Iterator::Construct(), CopyData(), CreateFullCopy(), GetInternalEnd(), GetInternalSize(), GetSerializedSize(), Initialize(), operator=(), RemoveAtEnd(), RemoveAtStart(), and Serialize().

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

src/network/model/buffer.h
src/network/model/buffer.cc

Classes

Public Member Functions

Private Types

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Typedef Documentation

◆ FreeList

Constructor & Destructor Documentation

◆ Buffer() [1/4]

◆ Buffer() [2/4]

◆ Buffer() [3/4]

◆ Buffer() [4/4]

◆ ~Buffer()

Member Function Documentation

◆ AddAtEnd() [1/2]

◆ AddAtEnd() [2/2]

◆ AddAtStart()

◆ Allocate()

◆ Begin()

◆ CheckInternalState()

◆ CopyData() [1/2]

◆ CopyData() [2/2]

◆ Create()

◆ CreateFragment()

◆ CreateFullCopy()

◆ Deallocate()

◆ Deserialize()

◆ End()

◆ GetInternalEnd()

◆ GetInternalSize()

◆ GetSerializedSize()

◆ GetSize()

◆ Initialize()

◆ operator=()

◆ PeekData()

◆ Recycle()

◆ RemoveAtEnd()

◆ RemoveAtStart()

◆ Serialize()

◆ TransformIntoRealBuffer()

Member Data Documentation

◆ g_freeList

◆ g_localStaticDestructor

◆ g_maxSize

◆ g_recommendedStart

◆ m_data

◆ m_end

◆ m_maxZeroAreaStart

◆ m_start

◆ m_zeroAreaEnd

◆ m_zeroAreaStart