#include <NCollection_IncAllocator.hxx>

Inheritance diagram for NCollection_IncAllocator:

Data Structures
struct	IBlock

Public Types
typedef void *	aligned_t

Public Types inherited from Standard_Transient
typedef void	base_type
	Returns a type descriptor about this object. More...

Public Member Functions
	NCollection_IncAllocator (size_t theBlockSize=DefaultBlockSize)
	Constructor. Note that this constructor does NOT setup mutex for using allocator concurrently from different threads, see SetThreadSafe() method. More...

void	SetThreadSafe (bool theIsThreadSafe=true)
	Setup mutex for thread-safe allocations. More...

virtual void *	Allocate (const size_t size) override
	Allocate memory with given size. Returns NULL on failure. More...

virtual void	Free (void *anAddress) override
	Free a previously allocated memory. Does nothing. More...

size_t	GetMemSize () const
	Diagnostic method, returns the total allocated size. More...

	~NCollection_IncAllocator ()
	Destructor (calls Clean() internally) More...

void *	Reallocate (void *anAddress, const size_t oldSize, const size_t newSize)
	Reallocation: it is always allowed but is only efficient with the last allocated item. More...

void	Reset (const Standard_Boolean doReleaseMem=Standard_True)
	Re-initialize the allocator so that the next Allocate call should start allocating in the very beginning as though the allocator is just constructed. Warning: make sure that all previously allocated data are no more used in your code! More...

Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor. More...

	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing. More...

Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter. More...

virtual	~Standard_Transient ()
	Destructor must be virtual. More...

virtual void	Delete () const
	Memory deallocator for transient classes. More...

virtual const opencascade::handle< Standard_Type > &	DynamicType () const
	Returns a type descriptor about this object. More...

Standard_Boolean	IsInstance (const opencascade::handle< Standard_Type > &theType) const
	Returns a true value if this is an instance of Type. More...

Standard_Boolean	IsInstance (const Standard_CString theTypeName) const
	Returns a true value if this is an instance of TypeName. More...

Standard_Boolean	IsKind (const opencascade::handle< Standard_Type > &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

Standard_Boolean	IsKind (const Standard_CString theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

Standard_Transient *	This () const
	Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero. More...

Standard_Integer	GetRefCount () const
	Get the reference counter of this object. More...

void	IncrementRefCounter () const
	Increments the reference counter of this object. More...

Standard_Integer	DecrementRefCounter () const
	Decrements the reference counter of this object; returns the decremented value. More...

Static Public Attributes
static const size_t	DefaultBlockSize = 12300
	Default size for the memory blocks - 12KB. More...

Protected Member Functions
void	Clean ()
	Flush all previously allocated data. All pointers returned by Allocate() become invalid – be very careful with this. More...

void *	allocateNewBlock (const size_t cSize)
	Allocate a new block and return a pointer to it only for internal usage . More...

Protected Member Functions inherited from NCollection_BaseAllocator
	NCollection_BaseAllocator (void)
	Constructor - prohibited. More...

Protected Attributes
Standard_Mutex *	myMutex

IBlock *	myFirstBlock

size_t	mySize

size_t	myMemSize

Additional Inherited Members
Static Public Member Functions inherited from NCollection_BaseAllocator
static const Handle< NCollection_BaseAllocator > &	CommonBaseAllocator (void)
	CommonBaseAllocator This method is designed to have the only one BaseAllocator (to avoid useless copying of collections). However one can use operator new to create more BaseAllocators, but it is injurious. More...

static void	StandardCallBack (const Standard_Boolean theIsAlloc, const Standard_Address theStorage, const Standard_Size theRoundSize, const Standard_Size theSize)
	Callback function to register alloc/free calls. More...

static void	PrintMemUsageStatistics ()
	Prints memory usage statistics cumulated by StandardCallBack. More...

Static Public Member Functions inherited from Standard_Transient
static const char *	get_type_name ()
	Returns a type descriptor about this object. More...

static const opencascade::handle< Standard_Type > &	get_type_descriptor ()
	Returns type descriptor of Standard_Transient class. More...

Detailed Description

Class NCollection_IncAllocator - incremental memory allocator. This class allocates memory on request returning the pointer to an allocated block. This memory is never returned to the system until the allocator is destroyed.

By comparison with the standard new() and malloc() calls, this method is faster and consumes very small additional memory to maintain the heap.

All pointers returned by Allocate() are aligned to the size of the data type "aligned_t". To modify the size of memory blocks requested from the OS, use the parameter of the constructor (measured in bytes); if this parameter is smaller than 25 bytes on 32bit or 49 bytes on 64bit, the block size will be the default 12 kbytes.

It is not recommended to use memory blocks larger than 16KB on Windows platform for the repeated operations because Low Fragmentation Heap is not going to be used for these allocations which may lead to memory fragmentation and the general performance slow down.

Note that this allocator is most suitable for single-threaded algorithms (consider creating dedicated allocators per working thread), and thread-safety of allocations is DISABLED by default (see SetThreadSafe()).

Member Typedef Documentation

◆ aligned_t

typedef void* NCollection_IncAllocator::aligned_t

Constructor & Destructor Documentation

◆ NCollection_IncAllocator()

NCollection_IncAllocator::NCollection_IncAllocator ( size_t theBlockSize = DefaultBlockSize )

Constructor. Note that this constructor does NOT setup mutex for using allocator concurrently from different threads, see SetThreadSafe() method.

The default size of the memory blocks is 12KB. It is not recommended to use memory blocks larger than 16KB on Windows platform for the repeated operations (and thus multiple allocations) because Low Fragmentation Heap is not going to be used for these allocations, leading to memory fragmentation and eventual performance slow down.

◆ ~NCollection_IncAllocator()

NCollection_IncAllocator::~NCollection_IncAllocator ( )

Destructor (calls Clean() internally)

Member Function Documentation

◆ Allocate()

virtual void* NCollection_IncAllocator::Allocate ( const size_t size )

overridevirtual

Allocate memory with given size. Returns NULL on failure.

Reimplemented from NCollection_BaseAllocator.

◆ allocateNewBlock()

void* NCollection_IncAllocator::allocateNewBlock ( const size_t cSize )

protected

Allocate a new block and return a pointer to it ** only for internal usage **.

◆ Clean()

void NCollection_IncAllocator::Clean ( )

protected

Flush all previously allocated data. All pointers returned by Allocate() become invalid – be very careful with this.

◆ Free()

virtual void NCollection_IncAllocator::Free ( void * anAddress )

overridevirtual

Free a previously allocated memory. Does nothing.

Reimplemented from NCollection_BaseAllocator.

◆ GetMemSize()

size_t NCollection_IncAllocator::GetMemSize ( ) const

Diagnostic method, returns the total allocated size.

◆ Reallocate()

void* NCollection_IncAllocator::Reallocate	(	void *	anAddress,
		const size_t	oldSize,
		const size_t	newSize
	)

Reallocation: it is always allowed but is only efficient with the last allocated item.

◆ Reset()

void NCollection_IncAllocator::Reset ( const Standard_Boolean doReleaseMem = Standard_True )

Re-initialize the allocator so that the next Allocate call should start allocating in the very beginning as though the allocator is just constructed. Warning: make sure that all previously allocated data are no more used in your code!

Parameters

doReleaseMem True - release all previously allocated memory, False - preserve it for future allocations.

◆ SetThreadSafe()

void NCollection_IncAllocator::SetThreadSafe ( bool theIsThreadSafe = true )

Setup mutex for thread-safe allocations.

Field Documentation

◆ DefaultBlockSize

const size_t NCollection_IncAllocator::DefaultBlockSize = 12300

static

Default size for the memory blocks - 12KB.

◆ myFirstBlock

IBlock* NCollection_IncAllocator::myFirstBlock

protected

◆ myMemSize

size_t NCollection_IncAllocator::myMemSize

protected

◆ myMutex

Standard_Mutex* NCollection_IncAllocator::myMutex

protected

◆ mySize

size_t NCollection_IncAllocator::mySize

protected

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

NCollection_IncAllocator.hxx

Data Structures

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ aligned_t

Constructor & Destructor Documentation

◆ NCollection_IncAllocator()

◆ ~NCollection_IncAllocator()

Member Function Documentation

◆ Allocate()

◆ allocateNewBlock()

◆ Clean()

◆ Free()

◆ GetMemSize()

◆ Reallocate()

◆ Reset()

◆ SetThreadSafe()

Field Documentation

◆ DefaultBlockSize

◆ myFirstBlock

◆ myMemSize

◆ myMutex

◆ mySize