Open CASCADE memory manager optimized for speed. More...

#include <Standard_MMgrOpt.hxx>

Inheritance diagram for Standard_MMgrOpt:

Public Types
typedef void(*	TPCallBackFunc) (const Standard_Boolean theIsAlloc, const Standard_Address theStorage, const Standard_Size theRoundSize, const Standard_Size theSize)
	Declaration of a type pointer to the callback function that should accept the following arguments:

Public Member Functions
	Standard_MMgrOpt (const Standard_Boolean aClear=Standard_True, const Standard_Boolean aMMap=Standard_True, const Standard_Size aCellSize=200, const Standard_Integer aNbPages=10000, const Standard_Size aThreshold=40000)
	Constructor. If aClear is True, the allocated emmory will be nullified. For description of other parameters, see description of the class above.

virtual	~Standard_MMgrOpt ()
	Frees all free lists and pools allocated for small blocks.

virtual Standard_Address	Allocate (const Standard_Size aSize)
	Allocate aSize bytes; see class description above.

virtual Standard_Address	Reallocate (Standard_Address thePtr, const Standard_Size theSize)
	Reallocate previously allocated aPtr to a new size; new address is returned. In case that aPtr is null, the function behaves exactly as Allocate.

virtual void	Free (Standard_Address thePtr)
	Free previously allocated block. Note that block can not all blocks are released to the OS by this method (see class description)

virtual Standard_Integer	Purge (Standard_Boolean isDestroyed)
	Release medium-sized blocks of memory in free lists to the system. Returns number of actually freed blocks.

Public Member Functions inherited from Standard_MMgrRoot
virtual	~Standard_MMgrRoot ()
	Virtual destructor; required for correct inheritance.

Static Public Member Functions
static void	SetCallBackFunction (TPCallBackFunc pFunc)
	Set the callback function. You may pass 0 there to turn off the callback. The callback function, if set, will be automatically called from within Allocate and Free methods.

Protected Member Functions
void	Initialize ()
	Internal - initialization of buffers.

Standard_Size *	AllocMemory (Standard_Size &aSize)
	Internal - allocation of memory using either malloc or memory mapped files. The size of the actually allocated block may be greater than requested one when memory mapping is used, since it is aligned to page size.

void	FreeMemory (Standard_Address aPtr, const Standard_Size aSize)
	Internal - deallocation of memory taken by AllocMemory.

void	FreePools ()
	Internal - free memory pools allocated for small size blocks.

Protected Attributes
Standard_Boolean	myClear
	option to clear allocated memory

Standard_Size	myFreeListMax
	last allocated index in the free blocks list

Standard_Size **	myFreeList
	free blocks list

Standard_Size	myCellSize
	small blocks size

Standard_Integer	myNbPages
	size (pages) for small block memory pools

Standard_Size	myPageSize
	system-dependent memory page size

Standard_Size *	myAllocList
	list of memory pools for small blocks

Standard_Size *	myNextAddr
	next free address in the active memory pool

Standard_Size *	myEndBlock
	end of the active memory pool

Standard_Integer	myMMap
	non-null if using memory mapped files for allocation of large blocks

Standard_Size	myThreshold
	large block size

Standard_Mutex	myMutex
	Mutex to protect free lists data.

Standard_Mutex	myMutexPools
	Mutex to protect small block pools data.

Detailed Description

Open CASCADE memory manager optimized for speed.

The behaviour is different for memory blocks of different sizes, according to specified options provided to constructor:

Small blocks with size less than or equal to aCellSize are allocated in big pools of memory. The parameter aNbPages specifies size of these pools in pages (operating system-dependent). When freed, small block is not returned to the system but added into free blocks list and reused when block of the same size is requested.
Medium size blocks with size less than aThreshold are allocated using malloc() or calloc() function but not returned to the system when method Free() is called; instead they are put into free list and reused when block of the same size is requested. Blocks of medium size stored in free lists can be released to the system (by free()) by calling method Purge().
Large blocks with size greater than or equal to aThreshold are allocated and freed directly: either using malloc()/calloc() and free(), or using memory mapped files (if option aMMap is True)

Thus the optimization of memory allocation/deallocation is reached for small and medium size blocks using free lists method; note that space allocated for small blocks cannot be (currently) released to the system while space for medium size blocks can be released by method Purge().

Note that destructor of that class frees all free lists and memory pools allocated for small blocks.

Note that size of memory blocks allocated by this memory manager is always rounded up to 16 bytes. In addition, 8 bytes are added at the beginning of the memory block to hold auxiliary information (size of the block when in use, or pointer to the next free block when in free list). This the expense of speed optimization. At the same time, allocating small blocks is usually less costly than directly by malloc since allocation is made once (when allocating a pool) and overheads induced by malloc are minimized.

Member Typedef Documentation

◆ TPCallBackFunc

typedef void(* Standard_MMgrOpt::TPCallBackFunc) (const Standard_Boolean theIsAlloc, const Standard_Address theStorage, const Standard_Size theRoundSize, const Standard_Size theSize)

Declaration of a type pointer to the callback function that should accept the following arguments:

Parameters

theIsAlloc	true if the data is allocated, false if it is freed
theStorage	address of the allocated/freed block
theRoundSize	the real rounded size of the block
theSize	the size of the block that was requested by application (this value is correct only if theIsAlloc is true)

Constructor & Destructor Documentation

◆ Standard_MMgrOpt()

Standard_MMgrOpt::Standard_MMgrOpt	(	const Standard_Boolean	aClear = `Standard_True`,
		const Standard_Boolean	aMMap = `Standard_True`,
		const Standard_Size	aCellSize = `200`,
		const Standard_Integer	aNbPages = `10000`,
		const Standard_Size	aThreshold = `40000`
	)

Constructor. If aClear is True, the allocated emmory will be nullified. For description of other parameters, see description of the class above.

◆ ~Standard_MMgrOpt()

virtual Standard_MMgrOpt::~Standard_MMgrOpt ( )

virtual

Frees all free lists and pools allocated for small blocks.

Member Function Documentation

◆ Allocate()

virtual Standard_Address Standard_MMgrOpt::Allocate ( const Standard_Size aSize )

virtual

Allocate aSize bytes; see class description above.

Implements Standard_MMgrRoot.

◆ AllocMemory()

Standard_Size * Standard_MMgrOpt::AllocMemory ( Standard_Size & aSize )

protected

Internal - allocation of memory using either malloc or memory mapped files. The size of the actually allocated block may be greater than requested one when memory mapping is used, since it is aligned to page size.

◆ Free()

virtual void Standard_MMgrOpt::Free ( Standard_Address thePtr )

virtual

Free previously allocated block. Note that block can not all blocks are released to the OS by this method (see class description)

Implements Standard_MMgrRoot.

◆ FreeMemory()

void Standard_MMgrOpt::FreeMemory	(	Standard_Address	aPtr,
		const Standard_Size	aSize
	)

protected

Internal - deallocation of memory taken by AllocMemory.

◆ FreePools()

void Standard_MMgrOpt::FreePools ( )

protected

Internal - free memory pools allocated for small size blocks.

◆ Initialize()

void Standard_MMgrOpt::Initialize ( )

protected

Internal - initialization of buffers.

◆ Purge()

virtual Standard_Integer Standard_MMgrOpt::Purge ( Standard_Boolean isDestroyed )

virtual

Release medium-sized blocks of memory in free lists to the system. Returns number of actually freed blocks.

Reimplemented from Standard_MMgrRoot.

◆ Reallocate()

virtual Standard_Address Standard_MMgrOpt::Reallocate	(	Standard_Address	thePtr,
		const Standard_Size	theSize
	)

virtual

Reallocate previously allocated aPtr to a new size; new address is returned. In case that aPtr is null, the function behaves exactly as Allocate.

Implements Standard_MMgrRoot.

◆ SetCallBackFunction()

static void Standard_MMgrOpt::SetCallBackFunction ( TPCallBackFunc pFunc )

static

Set the callback function. You may pass 0 there to turn off the callback. The callback function, if set, will be automatically called from within Allocate and Free methods.

Field Documentation

◆ myAllocList

Standard_Size* Standard_MMgrOpt::myAllocList

protected

list of memory pools for small blocks

◆ myCellSize

Standard_Size Standard_MMgrOpt::myCellSize

protected

small blocks size

◆ myClear

Standard_Boolean Standard_MMgrOpt::myClear

protected

option to clear allocated memory

◆ myEndBlock

Standard_Size* Standard_MMgrOpt::myEndBlock

protected

end of the active memory pool

◆ myFreeList

Standard_Size** Standard_MMgrOpt::myFreeList

protected

free blocks list

◆ myFreeListMax

Standard_Size Standard_MMgrOpt::myFreeListMax

protected

last allocated index in the free blocks list

◆ myMMap

Standard_Integer Standard_MMgrOpt::myMMap

protected

non-null if using memory mapped files for allocation of large blocks

◆ myMutex

Standard_Mutex Standard_MMgrOpt::myMutex

protected

Mutex to protect free lists data.

◆ myMutexPools

Standard_Mutex Standard_MMgrOpt::myMutexPools

protected

Mutex to protect small block pools data.

◆ myNbPages

Standard_Integer Standard_MMgrOpt::myNbPages

protected

size (pages) for small block memory pools

◆ myNextAddr

Standard_Size* Standard_MMgrOpt::myNextAddr

protected

next free address in the active memory pool

◆ myPageSize

Standard_Size Standard_MMgrOpt::myPageSize

protected

system-dependent memory page size

◆ myThreshold

Standard_Size Standard_MMgrOpt::myThreshold

protected

large block size

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

Standard_MMgrOpt.hxx

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ TPCallBackFunc

Constructor & Destructor Documentation

◆ Standard_MMgrOpt()

◆ ~Standard_MMgrOpt()

Member Function Documentation

◆ Allocate()

◆ AllocMemory()

◆ Free()

◆ FreeMemory()

◆ FreePools()

◆ Initialize()

◆ Purge()

◆ Reallocate()

◆ SetCallBackFunction()

Field Documentation

◆ myAllocList

◆ myCellSize

◆ myClear

◆ myEndBlock

◆ myFreeList

◆ myFreeListMax

◆ myMMap

◆ myMutex

◆ myMutexPools

◆ myNbPages

◆ myNextAddr

◆ myPageSize

◆ myThreshold