SG::initParams< T, clear, no_ctor, no_dtor > Struct Template Reference

Heap-based allocator. More...

#include <ArenaHeapAllocator.h>

Inheritance diagram for SG::initParams< T, clear, no_ctor, no_dtor >:

Collaboration diagram for SG::initParams< T, clear, no_ctor, no_dtor >:

Public Types
typedef ArenaAllocatorBase::initParams< T, clear, no_ctor, no_dtor >	Base

Public Member Functions
	initParams (size_t nblock=1000, const std::string &name="")
	Constructor.
ArenaAllocatorBase::Params	params () const
	Return an initialized parameters structure.
	operator ArenaAllocatorBase::Params () const
	Return an initialized parameters structure.
	operator Params () const
	Return an initialized parameters structure.

Private Attributes
size_t	m_nblock
	Saved value of the number of elements to allocate per block.
std::string	m_name
	Saved value of the allocator name.

Detailed Description

template<typename T, bool clear = false, bool no_ctor = false, bool no_dtor = false>
struct SG::initParams< T, clear, no_ctor, no_dtor >

Heap-based allocator.

See Arena.h for an overview of the arena-based memory allocators.

This is a block-based memory allocator, with heap-like behavior. This allows freeing individual elements, but we don't implement resetTo or an iterator.

There are some extra costs though.

• We need an additional pointer (`link') for each free element.

  By default, this is done by increasing the element size by a pointer, since we don't know whether there is data in the element itself that must be preserved across free/allocate. However, if you know that part of the element may be safely while it is free, then the allocator can be configured to use that as the link instead.

• When reset() is called, we need to call clear() on all allocated elements (if it is defined). If canReclear is set, then we just call clear() on all elements in allocated blocks on reset(), regardless of whether or not the individual elements are allocated or not. Otherwise, we make two passes over the elements, first to build a list of those that are allocated and second to actually call clear().

  An intermediate strategy, not currently implemented, could be used if the link does not overlap the element: set the link to a magic value when an element is allocated. */ class ArenaHeapAllocator : public ArenaBlockAllocatorBase { public: /**

Helper to initialize a parameters structure.

This creates a Params class appropriately initialized for class T. Assumptions made:

• The constructor and destructor calls will be filled in if non-trivial, unless no_ctor or no_dtor is set to true.
• The clear call will be filled in if the optional template parameter clear is true.
• No space will be reserved for an extra link.
• canReclear is true and mustClear is false.
• The link will be allocated externally to the element.

If these are not appropriate, you can derive from this class and make the appropriate changes.

Definition at line 86 of file ArenaHeapAllocator.h.

Member Typedef Documentation

Base

template<typename T, bool clear = false, bool no_ctor = false, bool no_dtor = false>

typedef ArenaAllocatorBase::initParams<T, clear, no_ctor, no_dtor> SG::initParams< T, clear, no_ctor, no_dtor >::Base

Definition at line 90 of file ArenaHeapAllocator.h.

Constructor & Destructor Documentation

initParams()

template<typename T, bool clear = false, bool no_ctor = false, bool no_dtor = false>

SG::initParams< T, clear, no_ctor, no_dtor >::initParams	(	size_t	nblock = 1000,
		const std::string &	name = "" )

Constructor.

Parameters

nblock	Value to set in the parameters structure for the number of elements to allocate per block.
name	Value to set in the parameters structure for the allocator name.

Member Function Documentation

operator ArenaAllocatorBase::Params()

template<typename T, bool clear = false, bool no_ctor = false, bool no_dtor = false>

SG::initParams< T, clear, no_ctor, no_dtor >::operator ArenaAllocatorBase::Params ( ) const

inline

Return an initialized parameters structure.

Definition at line 107 of file ArenaHeapAllocator.h.

{ return params(); }

operator Params()

SG::ArenaAllocatorBase::initParams< T, clear, no_ctor, no_dtor >::operator Params ( ) const

inlineinherited

Return an initialized parameters structure.

Definition at line 335 of file ArenaAllocatorBase.h.

{ return params(); }

params()

template<typename T, bool clear = false, bool no_ctor = false, bool no_dtor = false>

ArenaAllocatorBase::Params SG::initParams< T, clear, no_ctor, no_dtor >::params

(

)

const

Return an initialized parameters structure.

Member Data Documentation

m_name

std::string SG::ArenaAllocatorBase::initParams< T, clear, no_ctor, no_dtor >::m_name

privateinherited

Saved value of the allocator name.

Definition at line 343 of file ArenaAllocatorBase.h.

m_nblock

size_t SG::ArenaAllocatorBase::initParams< T, clear, no_ctor, no_dtor >::m_nblock

privateinherited

Saved value of the number of elements to allocate per block.

Definition at line 340 of file ArenaAllocatorBase.h.

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

• ArenaHeapAllocator.h