A class that keeps ownership of a chain of linked DataBuffer references. More...

#include <DataBuffer.hxx>

Public Member Functions
	LinkedDataBufferPtr (LinkedDataBufferPtr &&o)
	Move constructor. Takes the ownership that o has. Leaves o as empty.

void	operator= (LinkedDataBufferPtr &&o)
	Move assignment operator.

	LinkedDataBufferPtr (const LinkedDataBufferPtr &)=delete
	We do not permit default copy operation.

void	operator= (const LinkedDataBufferPtr &)=delete

void	reset (const LinkedDataBufferPtr &o, ssize_t size=-1)
	Takes a reference of o, taking a prefix of len size (or all the data).

void	reset (DataBuffer *buf)
	Clears the current contents and replaces it with the empty buf.

void	reset (DataBuffer *buf, unsigned skip, unsigned size)
	Set to a single data buffer.

void	append_empty_buffer (DataBuffer *buf)
	Adds an empty buffer to the end of this buffer chain.

void	reset ()
	Deallocates the current content (by releasing the references).

uint8_t *	data_write_pointer ()

void	data_write_advance (size_t len)
	Advances the tail pointer after a write occurred into the tail.

const uint8_t *	data_read_pointer (size_t *len)
	Retrieves a pointer where data can be read out of the buffer.

void	data_read_advance (size_t len)
	Advances the head pointer.

DataBuffer *	head () const

DataBuffer *	tail () const

unsigned	skip () const

unsigned	size () const

size_t	free () const

LinkedDataBufferPtr	transfer_head (size_t len)
	Transfers the ownership of the prefix of this buffer.

void	append_to (std::string *recvd) const
	Appends all content in this buffer to an std::string.

bool	try_append_from (const LinkedDataBufferPtr &o, bool add_link=false)
	Attempt to combine *this with o into a single LinkedDataBufferPtr this.

Private Member Functions
void	clear ()
	Internal helper function of constructors and reset functions.

Private Attributes
DataBuffer *	head_ {nullptr}
	First buffer in the chain. This is the root of the ownership.

DataBuffer *	tail_ {nullptr}
	Last buffer in the chain. This is where we can extend the owned bytes.

size_t	size_ {0}
	How many bytes we have filled in (counting starts at head.data() + skip_).

uint16_t	skip_ {0}
	How many bytes to skip in the head buffer.

int16_t	free_ {0}
	If >= 0: How many free bytes are there in the tail buffer.

Detailed Description

A class that keeps ownership of a chain of linked DataBuffer references.

Definition at line 205 of file DataBuffer.hxx.

Constructor & Destructor Documentation

◆ LinkedDataBufferPtr() [1/3]

LinkedDataBufferPtr::LinkedDataBufferPtr ( )

inline

Definition at line 211 of file DataBuffer.hxx.

◆ ~LinkedDataBufferPtr()

LinkedDataBufferPtr::~LinkedDataBufferPtr ( )

inline

Definition at line 215 of file DataBuffer.hxx.

◆ LinkedDataBufferPtr() [2/3]

LinkedDataBufferPtr::LinkedDataBufferPtr ( LinkedDataBufferPtr && o )

inline

Move constructor. Takes the ownership that o has. Leaves o as empty.

Definition at line 221 of file DataBuffer.hxx.

◆ LinkedDataBufferPtr() [3/3]

LinkedDataBufferPtr::LinkedDataBufferPtr ( const LinkedDataBufferPtr & )

delete

We do not permit default copy operation.

Use the reset() function for that.

Member Function Documentation

◆ append_empty_buffer()

void LinkedDataBufferPtr::append_empty_buffer ( DataBuffer * buf )

inline

Adds an empty buffer to the end of this buffer chain.

Parameters

buf	is a new, empty DataBuffer. Ownership will be taken. The size() value of it has to be denoting the amount of available bytes.

Definition at line 311 of file DataBuffer.hxx.

◆ append_to()

void LinkedDataBufferPtr::append_to ( std::string * recvd ) const

inline

Appends all content in this buffer to an std::string.

Parameters

recvd string to append data to.

Definition at line 509 of file DataBuffer.hxx.

◆ clear()

void LinkedDataBufferPtr::clear ( )

inlineprivate

Internal helper function of constructors and reset functions.

Clears the current structure (references have to have been dealt with before).

Definition at line 616 of file DataBuffer.hxx.

◆ data_read_advance()

void LinkedDataBufferPtr::data_read_advance ( size_t len )

inline

Advances the head pointer.

Typically used after a successful read happened.

Parameters

len	how many bytes to advance the read pointer.

Definition at line 397 of file DataBuffer.hxx.

◆ data_read_pointer()

const uint8_t * LinkedDataBufferPtr::data_read_pointer ( size_t * len )

inline

Retrieves a pointer where data can be read out of the buffer.

Parameters

len	will be filled in with the number of available bytes to read at this point.

Returns: the read pointer, or nullptr if there is no data in this buffer.

Definition at line 376 of file DataBuffer.hxx.

◆ data_write_advance()

void LinkedDataBufferPtr::data_write_advance ( size_t len )

inline

Advances the tail pointer after a write occurred into the tail.

Parameters

len	how many bytes were written into the space pointed to by data_write_pointer().

Definition at line 363 of file DataBuffer.hxx.

◆ data_write_pointer()

uint8_t * LinkedDataBufferPtr::data_write_pointer ( )

inline

Returns: the pointer where data can be appended into the tail of this buffer chain. Use free() to know how many bytes can be written here.

Definition at line 351 of file DataBuffer.hxx.

◆ free()

size_t LinkedDataBufferPtr::free ( ) const

inline

Returns: the number of bytes that can be written into the tail of this buffer chain, at data_write_pointer().

Definition at line 458 of file DataBuffer.hxx.

◆ head()

DataBuffer * LinkedDataBufferPtr::head ( ) const

inline

Returns: buffer that is at head.

Definition at line 433 of file DataBuffer.hxx.

◆ operator=()

void LinkedDataBufferPtr::operator= ( LinkedDataBufferPtr && o )

inline

Move assignment operator.

Takes the ownership that o has. Leaves o as empty.

Definition at line 233 of file DataBuffer.hxx.

◆ reset() [1/4]

void LinkedDataBufferPtr::reset ( )

inline

Deallocates the current content (by releasing the references).

Definition at line 333 of file DataBuffer.hxx.

◆ reset() [2/4]

void LinkedDataBufferPtr::reset	(	const LinkedDataBufferPtr &	o,
		ssize_t	size = `-1`
	)

inline

Takes a reference of o, taking a prefix of len size (or all the data).

The current buffer becomes non-extensible.

Parameters

o	an owned LinkedDataBufferPtr
size	is non-negative, this is how many bytes from the beginning of o will be copied. If default (negative), takes all bytes that are filled.

Definition at line 255 of file DataBuffer.hxx.

◆ reset() [3/4]

void LinkedDataBufferPtr::reset ( DataBuffer * buf )

inline

Clears the current contents and replaces it with the empty buf.

Parameters

buf	is a new, empty DataBuffer. Ownership will be taken. The size() value of it has to be denoting the amount of available bytes.

Definition at line 283 of file DataBuffer.hxx.

◆ reset() [4/4]

void LinkedDataBufferPtr::reset	(	DataBuffer *	buf,
		unsigned	skip,
		unsigned	size
	)

inline

Set to a single data buffer.

Parameters

buf	is a filled-in data buffer. Takes ownership. Must be a single (non-chained) buffer.
skip	how many bytes to skip at the beginning
size	how many bytes to take after skip bytes.

Definition at line 298 of file DataBuffer.hxx.

◆ size()

unsigned LinkedDataBufferPtr::size ( ) const

inline

Returns: how many bytes are filled in the current buffer.

Definition at line 451 of file DataBuffer.hxx.

◆ skip()

unsigned LinkedDataBufferPtr::skip ( ) const

inline

Returns: how many bytes to skip from the head buffer.

Definition at line 445 of file DataBuffer.hxx.

◆ tail()

DataBuffer * LinkedDataBufferPtr::tail ( ) const

inline

Returns: buffer that is at the tail.

Definition at line 439 of file DataBuffer.hxx.

◆ transfer_head()

LinkedDataBufferPtr LinkedDataBufferPtr::transfer_head ( size_t len )

inline

Transfers the ownership of the prefix of this buffer.

The tail will remain in the current buffer chain as an extra reference. Any free space in the tail will also remain in the current bufferptr.

Parameters

len	how many bytes at the beginning (starting at skip_) to transfer. Must reach into the tail buffer, meaning that at least one byte from the tail buffer must be transferred.

Returns: a new (moveable) LinkedDataBufferPtr that will get the ownership of the head. It will be non-extendible.

Definition at line 475 of file DataBuffer.hxx.

◆ try_append_from()

bool LinkedDataBufferPtr::try_append_from	(	const LinkedDataBufferPtr &	o,
		bool	add_link = `false`
	)

inline

Attempt to combine *this with o into a single LinkedDataBufferPtr this.

This tries to do *this += o. It will succeed if o.head() == this->tail() and the bytes in these buffers are back to back.

Parameters

o	a LinkedDataBuffer with data payload.
add_link	creates a tail-to-head link if none exist yet between *this and o.head_. This is fundamentally dangerous, do it only if there is no shared ownership of this->tail_.

Returns: true if append succeeded. If false, nothing was changed.

Definition at line 538 of file DataBuffer.hxx.

Member Data Documentation

◆ free_

int16_t LinkedDataBufferPtr::free_ {0}

private

If >= 0: How many free bytes are there in the tail buffer.

If < 0: non-appendable buffer, the -offset of the first byte in the tail buffer that's after the payload. In other words, -1 * the skip() of the next linked buffer. In other words, -1 * the end pointer in the tail buffer.

Definition at line 635 of file DataBuffer.hxx.

◆ head_

DataBuffer* LinkedDataBufferPtr::head_ {nullptr}

private

First buffer in the chain. This is the root of the ownership.

Definition at line 623 of file DataBuffer.hxx.

◆ size_

size_t LinkedDataBufferPtr::size_ {0}

private

How many bytes we have filled in (counting starts at head.data() + skip_).

Definition at line 628 of file DataBuffer.hxx.

◆ skip_

uint16_t LinkedDataBufferPtr::skip_ {0}

private

How many bytes to skip in the head buffer.

Definition at line 630 of file DataBuffer.hxx.

◆ tail_

DataBuffer* LinkedDataBufferPtr::tail_ {nullptr}

private

Last buffer in the chain. This is where we can extend the owned bytes.

Definition at line 625 of file DataBuffer.hxx.

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

DataBuffer.hxx

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ LinkedDataBufferPtr() [1/3]

◆ ~LinkedDataBufferPtr()

◆ LinkedDataBufferPtr() [2/3]

◆ LinkedDataBufferPtr() [3/3]

Member Function Documentation

◆ append_empty_buffer()

◆ append_to()

◆ clear()

◆ data_read_advance()

◆ data_read_pointer()

◆ data_write_advance()

◆ data_write_pointer()

◆ free()

◆ head()

◆ operator=()

◆ reset() [1/4]

◆ reset() [2/4]

◆ reset() [3/4]

◆ reset() [4/4]

◆ size()

◆ skip()

◆ tail()

◆ transfer_head()

◆ try_append_from()

Member Data Documentation

◆ free_

◆ head_

◆ size_

◆ skip_

◆ tail_