Reference on memory from memory pool. More...

#include <dabc/Buffer.h>

Inheritance diagram for dabc::Buffer:

Public Member Functions
bool	Append (Buffer &src, bool moverefs=true) throw ()
	Append content of provided buffer. More...

std::string	AsStdString ()
	Convert content of the buffer into std::string. More...

bool	CanSafelyChange () const
	Returns true when user can modify buffer content without any doubts. More...

BufferSize_t	CopyFrom (const Buffer &srcbuf, BufferSize_t len=0) throw ()
	Copy content from source buffer. More...

BufferSize_t	CopyFromStr (const char *src, unsigned len=0) throw ()
	Copy data from string. More...

BufferSize_t	CopyTo (void *ptr, BufferSize_t len) const throw ()
	Copy content into provided raw buffer. More...

void	CutFromBegin (BufferSize_t len)
	Remove part of buffer from the beginning. More...

Buffer	Duplicate () const
	Duplicates instance of Buffer with new segments list independent from source. More...

Buffer	GetNextPart (Pointer &ptr, BufferSize_t len, bool allowsegmented=true) throw ()
	Returns reference on the part of the memory, referenced by the object. More...

Reference	GetPool () const
	Returns reference on the pool, in user code MemoryPoolRef can be used like dabc::Buffer buf = Recv(); dabc::MemoryPoolRef pool = buf.GetPool();. More...

BufferSize_t	GetTotalSize () const
	Return total size of all buffer segments. More...

unsigned	GetTypeId () const

Buffer	HandOver ()
	Method hands over buffer, that source will be emptied at the end. More...

bool	Insert (BufferSize_t pos, Buffer &src, bool moverefs=true)
	Insert content of buffer at specified position. More...

bool	IsPool (const Reference &pool) const
	Returns true if buffer produced by the pool provided as reference. More...

void	MakeEmpty (unsigned capacity=8)
	Method produce buffer with empty segments list Such buffer can be used to collect segments from other buffers without disturbing other bufs. More...

unsigned	NumSegments () const
	Returns number of segment in buffer. More...

bool	Prepend (Buffer &src, bool moverefs=true) throw ()
	Prepend content of provided buffer. More...

unsigned	SegmentId (unsigned n=0) const
	Returns id of the segment, no any boundary checks. More...

void *	SegmentPtr (unsigned n=0) const
	Returns pointer on the segment, no any boundary checks. More...

MemSegment *	Segments () const

unsigned	SegmentSize (unsigned n=0) const
	Returns size on the segment, no any boundary checks. More...

void	SetTotalSize (BufferSize_t len)
	Set total length of the buffer to specified value Size cannot be bigger than original size of the buffer. More...

void	SetTypeId (unsigned tid)

Public Member Functions inherited from dabc::Reference
bool	AddChild (Object *obj)
	Add child to list of object children. More...

const char *	ClassName () const
	Return class name of referenced object, if object not assigned, returns "---". More...

void	Destroy () throw ()
	Release reference and starts destroyment of referenced object. More...

Reference	FindChild (const char *name) const
	Searches for child in referenced object. More...

bool	GetAllChildRef (ReferencesVector *vect) const
	Return references for all childs. More...

Reference	GetChild (unsigned n) const
	Return reference on child n. More...

Reference	GetFolder (const std::string &name, bool force=false) throw ()
	Return folder of specified name, no special symbols are allowed. More...

const char *	GetName () const
	Return name of referenced object, if object not assigned, returns "---". More...

Object *	GetObject () const
	Return pointer on the object. More...

Object *	GetParent () const
	Returns pointer on parent object. More...

Reference	GetParentRef () const
	Returns reference on parent object. More...

bool	IsName (const char *name) const
	Returns true if object name is the same as specified one. More...

std::string	ItemName (bool compact=true) const
	Produce string, which can be used as name argument in dabc::mgr.FindItem(name) call. More...

bool	null () const
	Returns true if reference contains nullptr. More...

unsigned	NumChilds () const
	Return number of childs in referenced object. More...

unsigned	NumReferences () const
	Returns number of references on the object. More...

bool	operator! () const
	Returns true if reference contains nullptr. More...

bool	operator!= (const Reference &src) const
	Compare operator - return true if references refer to different object. More...

bool	operator!= (Object *obj) const
	Compare operator - return true if reference refer to different objects. More...

Object *	operator() () const
	Return pointer on the object. More...

Reference &	operator<< (Reference &src) throw ()
	Move operator - reference moved from source to target. More...

Reference &	operator= (const Reference &src) throw ()
	Assignment operator - copy reference. More...

Reference &	operator= (Object *obj) throw ()
	Assignment operator - copy reference. More...

bool	operator== (const Reference &src) const
	Compare operator - return true if references refer to same object. More...

bool	operator== (Object *obj) const
	Compare operator - return true if reference refer to same object. More...

void	Print (int lvl=0, const char *from=0) const
	Show on debug output content of reference. More...

	Reference (const Reference &src) throw ()
	Copy constructor, if source is transient than source reference will be emptied. More...

	Reference (Object *obj=nullptr)
	Constructor, creates reference on the object. More...

std::string	RelativeName (const dabc::Reference &topitem)
	Produce name, which can be used to find item, calling topitem.FindChild(). More...

void	Release () throw ()
	Releases reference on the object. More...

bool	RemoveChild (const char *name, bool cleanup=true)
	Remove child with given name and return reference on that child. More...

bool	RemoveChilds (bool cleanup=true)
	Remove all childs in referenced object If cleanup true (default) and object is owner, all objects will be destroyed. More...

void	SetAutoDestroy (bool on=true)
	Set autodestroy flag for the object Once enabled, object will be destroyed when last reference will be cleared. More...

void	SetObject (Object *obj, bool withmutex=true)
	Direct set of object to reference. More...

Reference	Take ()
	Copy reference to output object. More...

virtual	~Reference ()
	Destructor, releases reference on the object. More...

Static Public Member Functions
static Buffer	CreateBuffer (BufferSize_t sz) throw ()
	This static method create independent buffer for any other memory pools Therefore it can be used in standalone case. More...

static Buffer	CreateBuffer (const void *ptr, unsigned size, bool owner=false, bool makecopy=false) throw ()
	This static method create Buffer instance, which contains pointer on specified peace of memory Therefore it can be used in standalone case. More...

Protected Member Functions
void	AllocateContainer (unsigned capacity)

void	Locate (BufferSize_t p, unsigned &seg_indx, unsigned &seg_shift) const

MemoryPool *	PoolPtr () const

Protected Member Functions inherited from dabc::Reference
bool	AcquireRefWithoutMutex (Reference &ref)
	Special method, which allows to generate new reference when object mutex is locked. More...

void	Assign (const Reference &src)
	Method used in copy constructor and assigned operations. More...

Mutex *	ObjectMutex () const

template<class T >
bool	verify_object (Object src, T &tgt)
	Method used in reference constructor/assignments to verify is object is suitable. More...

Friends
class	MemoryPool

Additional Inherited Members
Protected Attributes inherited from dabc::Reference
Object *	fObj
	pointer on the object More...

Detailed Description

Reference on memory from memory pool.

Central class for memory usage concept in DABC framework.

All memory for data transfer should be pre-allocated in dabc::MemoryPool. Buffer class provides access to that memory.

Main concepts:

avoid memcpy as much as possible
exchange references between local modules
support zero-copy where possible (like InfiniBand VERBS)
reuse memory from memory pool, do not allocate/deallocate memory every time
provide possibility to gather many segments together (segments list)

Actual class description need to be done.

Definition at line 135 of file Buffer.h.

Member Function Documentation

◆ Locate()

void dabc::Buffer::Locate	(	BufferSize_t	p,
		unsigned &	seg_indx,
		unsigned &	seg_shift
	)		const

protected

Definition at line 172 of file Buffer.cxx.

◆ AllocateContainer()

void dabc::Buffer::AllocateContainer ( unsigned capacity )

protected

Definition at line 462 of file Buffer.cxx.

◆ PoolPtr()

dabc::MemoryPool * dabc::Buffer::PoolPtr ( ) const

protected

Definition at line 83 of file Buffer.cxx.

◆ SetTypeId()

void dabc::Buffer::SetTypeId ( unsigned tid )

inline

Definition at line 151 of file Buffer.h.

◆ GetTypeId()

unsigned dabc::Buffer::GetTypeId ( ) const

inline

Definition at line 152 of file Buffer.h.

◆ GetPool()

dabc::Reference dabc::Buffer::GetPool ( ) const

Returns reference on the pool, in user code MemoryPoolRef can be used like dabc::Buffer buf = Recv(); dabc::MemoryPoolRef pool = buf.GetPool();.

Definition at line 78 of file Buffer.cxx.

◆ IsPool()

bool dabc::Buffer::IsPool ( const Reference & pool ) const

inline

Returns true if buffer produced by the pool provided as reference.

Definition at line 160 of file Buffer.h.

◆ NumSegments()

unsigned dabc::Buffer::NumSegments ( ) const

inline

Returns number of segment in buffer.

Definition at line 163 of file Buffer.h.

◆ Segments()

MemSegment* dabc::Buffer::Segments ( ) const

inline

Definition at line 165 of file Buffer.h.

◆ SegmentId()

unsigned dabc::Buffer::SegmentId ( unsigned n = 0 ) const

inline

Returns id of the segment, no any boundary checks.

Definition at line 168 of file Buffer.h.

◆ SegmentPtr()

void* dabc::Buffer::SegmentPtr ( unsigned n = 0 ) const

inline

Returns pointer on the segment, no any boundary checks.

Definition at line 171 of file Buffer.h.

◆ SegmentSize()

unsigned dabc::Buffer::SegmentSize ( unsigned n = 0 ) const

inline

Returns size on the segment, no any boundary checks.

Definition at line 174 of file Buffer.h.

◆ GetTotalSize()

dabc::BufferSize_t dabc::Buffer::GetTotalSize ( ) const

Return total size of all buffer segments.

Definition at line 91 of file Buffer.cxx.

◆ Duplicate()

dabc::Buffer dabc::Buffer::Duplicate ( ) const

Duplicates instance of Buffer with new segments list independent from source.

Means original instance will remain as is. Memory which is referenced by Buffer object is not duplicated or copied, means both instances are reference same memory regions. This method can be time consuming, while pool mutex should be locked and reference counter of all segments should be incremented. When created instance destroyed, same operation in reverse order will be performed. Method must be used when new instance should be used in other thread while initial instance Do not duplicate buffer without real need for that.

Definition at line 192 of file Buffer.cxx.

◆ HandOver()

Buffer dabc::Buffer::HandOver ( )

inline

Method hands over buffer, that source will be emptied at the end.

This method creates temporary object which could be deliver to the any other method as argument. At the same time original object forgets buffer and will be empty at the end of the call. Typical place where it should be used is return method when source want to forget buffer itself:

dabc::Buffer MyClass::GetLast() { fLastBuf.SetTotalSize(1024); fLastBuf.SetTypeId(129); return fLastBuf.HandOver(); }

If one wants to keep reference on the memory after such call one should do: ... return fLastBuf; ...

Definition at line 211 of file Buffer.h.

◆ MakeEmpty()

void dabc::Buffer::MakeEmpty ( unsigned capacity = 8 )

inline

Method produce buffer with empty segments list Such buffer can be used to collect segments from other buffers without disturbing other bufs.

Definition at line 216 of file Buffer.h.

◆ SetTotalSize()

void dabc::Buffer::SetTotalSize ( BufferSize_t len )

Set total length of the buffer to specified value Size cannot be bigger than original size of the buffer.

Definition at line 99 of file Buffer.cxx.

◆ CutFromBegin()

void dabc::Buffer::CutFromBegin ( BufferSize_t len )

Remove part of buffer from the beginning.

Definition at line 139 of file Buffer.cxx.

◆ Append()

bool dabc::Buffer::Append	(	Buffer &	src,
		bool	moverefs = `true`
	)
throw	(
	)

Append content of provided buffer.

If source buffer belong to other memory pool, content will be copied.

Parameters

[in]	src	buffer to append
[in]	moverefs	if true, references moved to the target and source buffer will be emptied

Returns: false if operation failed, otherwise true

Definition at line 215 of file Buffer.cxx.

◆ Prepend()

bool dabc::Buffer::Prepend	(	Buffer &	src,
		bool	moverefs = `true`
	)
throw	(
	)

Prepend content of provided buffer.

If source buffer belong to other memory pool, content will be copied.

Parameters

[in]	src	buffer to prepend
[in]	moverefs	if true, references moved to the target and source buffer will be emptied

Returns: false if operation failed, otherwise true

Definition at line 220 of file Buffer.cxx.

◆ Insert()

bool dabc::Buffer::Insert	(	BufferSize_t	pos,
		Buffer &	src,
		bool	moverefs = `true`
	)

Insert content of buffer at specified position.

If source buffer belong to other memory pool, content will be copied.

Parameters

[in]	pos	position at which buffer must be inserted
[in]	src	buffer to insert
[in]	moverefs	if true, references moved to the target and source buffer will be emptied

Returns: false if operation failed, otherwise true

Definition at line 225 of file Buffer.cxx.

◆ AsStdString()

std::string dabc::Buffer::AsStdString ( )

Convert content of the buffer into std::string.

Definition at line 317 of file Buffer.cxx.

◆ CopyFrom()

dabc::BufferSize_t dabc::Buffer::CopyFrom	(	const Buffer &	srcbuf,
		BufferSize_t	len = `0`
	)
throw	(
	)

Copy content from source buffer.

Parameters

[in]	srcbuf	source buffer
[in]	len	bytes to copy, if 0 - whole buffer

Returns: actual number of bytes copied

Definition at line 333 of file Buffer.cxx.

◆ CopyFromStr()

dabc::BufferSize_t dabc::Buffer::CopyFromStr	(	const char *	src,
		unsigned	len = `0`
	)
throw	(
	)

Copy data from string.

Parameters

[in]	src	source string
[in]	len	bytes copied, (if 0, complete string excluding trailing null)

Returns: actual number of bytes copied

Definition at line 339 of file Buffer.cxx.

◆ CopyTo()

dabc::BufferSize_t dabc::Buffer::CopyTo	(	void *	ptr,
		BufferSize_t	len
	)		const
throw	(
	)

Copy content into provided raw buffer.

Parameters

[in]	ptr	pointer to destination memory
[in]	len	number of bytes to copy.

Returns: actual number of bytes copied

Definition at line 344 of file Buffer.cxx.

◆ GetNextPart()

dabc::Buffer dabc::Buffer::GetNextPart	(	Pointer &	ptr,
		BufferSize_t	len,
		bool	allowsegmented = `true`
	)
throw	(
	)

Returns reference on the part of the memory, referenced by the object.

Parameters

[in,out]	ptr	pointer where next part will be extracted
[in]	len	length of memory piece (0 - rest size of current segment will be delivered).
[in]	allowsegmented	defines if return memory peace could be segmented or not.

Returns: reference of buffer part or empty buffer when requested memory size is not available in the source buffer

This method could be used to manage small peaces of memory in the memory pool with big buffers. For instance, one need some small headers which should managed separately from the main data. Than one need to take big buffer from the pool and extract by small pieces:

// somewhere in the initialization Buffer buf = Pool()->TakeBuffer(64000);

// later in the code Buffer data = Recv(); Buffer hdr = buf.GetNextPart(16) data.Prepend(hdr); Send(data);

Of course, one should check if buffer is expired and one need to take next piece from the memory pool.

TODO: one can exclude pointer and just cut buffer pieces until buffer is empty

Definition at line 349 of file Buffer.cxx.

◆ CanSafelyChange()

bool dabc::Buffer::CanSafelyChange ( ) const

Returns true when user can modify buffer content without any doubts.

It happens when refcnt==1 for each memory segments

Definition at line 451 of file Buffer.cxx.

◆ CreateBuffer() [1/2]

dabc::Buffer dabc::Buffer::CreateBuffer	(	BufferSize_t	sz	)
throw	(
	)

static

This static method create independent buffer for any other memory pools Therefore it can be used in standalone case.

Definition at line 419 of file Buffer.cxx.

◆ CreateBuffer() [2/2]

dabc::Buffer dabc::Buffer::CreateBuffer	(	const void *	ptr,
		unsigned	size,
		bool	owner = `false`,
		bool	makecopy = `false`
	)
throw	(
	)

static

This static method create Buffer instance, which contains pointer on specified peace of memory Therefore it can be used in standalone case.

Definition at line 424 of file Buffer.cxx.

Friends And Related Function Documentation

◆ MemoryPool

friend class MemoryPool

friend

Definition at line 137 of file Buffer.h.

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

base/dabc/Buffer.h
base/src/Buffer.cxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ Locate()

◆ AllocateContainer()

◆ PoolPtr()

◆ SetTypeId()

◆ GetTypeId()

◆ GetPool()

◆ IsPool()

◆ NumSegments()

◆ Segments()

◆ SegmentId()

◆ SegmentPtr()

◆ SegmentSize()

◆ GetTotalSize()

◆ Duplicate()

◆ HandOver()

◆ MakeEmpty()

◆ SetTotalSize()

◆ CutFromBegin()

◆ Append()

◆ Prepend()

◆ Insert()

◆ AsStdString()

◆ CopyFrom()

◆ CopyFromStr()

◆ CopyTo()

◆ GetNextPart()

◆ CanSafelyChange()

◆ CreateBuffer() [1/2]

◆ CreateBuffer() [2/2]

Friends And Related Function Documentation

◆ MemoryPool