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// File: NCollection_IncAllocator.hxx
// Created: 12.04.02 19:45:14
// Author: Alexander GRIGORIEV
// Copyright: Open Cascade 2002
#ifndef NCollection_IncAllocator_HeaderFile
#define NCollection_IncAllocator_HeaderFile
#include <NCollection_BaseAllocator.hxx>
/**
* 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 24 kbytes
*/
class NCollection_IncAllocator : public NCollection_BaseAllocator
{
public:
// The type defining the alignement of allocated objects
typedef void * aligned_t;
// ---------- PUBLIC METHODS ----------
//! Constructor
Standard_EXPORT NCollection_IncAllocator (const size_t theBlockSize = 24600);
//! Allocate memory with given size. Returns NULL on failure
Standard_EXPORT virtual void* Allocate (const size_t size);
//! Free a previously allocated memory. Does nothing
Standard_EXPORT virtual void Free (void *anAddress);
//! Diagnostic method, returns the total allocated size
Standard_EXPORT size_t GetMemSize () const;
//! Destructor (calls Clean() internally)
Standard_EXPORT ~NCollection_IncAllocator ();
//! Reallocation: it is always allowed but is only efficient with the
//! last allocated item
Standard_EXPORT void * Reallocate (void * anAddress,
const size_t oldSize,
const size_t newSize);
//! Re-initialize the allocator so that the next Allocate call should
//! start allocating in the very begining as though the allocator is just
//! constructed. Warning: make sure that all previously allocated data are
//! no more used in your code!
//! @param doReleaseMem
//! True - release all previously allocated memory, False - preserve it
//! for future allocations.
Standard_EXPORT void Reset (const Standard_Boolean
doReleaseMem=Standard_True);
protected:
struct IBlock;
//! Flush all previously allocated data. All pointers returned by
//! Allocate() become invalid -- be very careful with this
Standard_EXPORT void Clean ();
//! Allocate a new block and return a pointer to it
//! ** only for internal usage **
void * allocateNewBlock (const size_t cSize);
private:
// Prohibited methods
NCollection_IncAllocator (const NCollection_IncAllocator&);
NCollection_IncAllocator& operator = (const NCollection_IncAllocator&);
protected:
// ----- PROTECTED CLASS IBlock -------
struct IBlock {
aligned_t * allocateInBlock (const size_t cSize)
{
aligned_t * aResult = p_free_space;
p_free_space += cSize;
return aResult;
}
aligned_t * p_free_space;
aligned_t * p_end_block;
struct IBlock * p_next;
};
protected:
// --------- PROTECTED FIELDS ---------
IBlock * myFirstBlock;
size_t mySize;
size_t myMemSize;
public:
// Declaration of CASCADE RTTI
DEFINE_STANDARD_RTTI (NCollection_IncAllocator)
};
// Definition of HANDLE object using Standard_DefineHandle.hxx
DEFINE_STANDARD_HANDLE (NCollection_IncAllocator, NCollection_BaseAllocator)
#endif
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