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/*=========================================================================
Program: Visualization Toolkit
Module: vtkHeap.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
// .NAME vtkHeap - replacement for malloc/free and new/delete
// .SECTION Description
// This class is a replacement for malloc/free and new/delete for software
// that has inherent memory leak or performance problems. For example,
// external software such as the PLY library (vtkPLY) and VRML importer
// (vtkVRMLImporter) are often written with lots of malloc() calls but
// without the corresponding free() invocations. The class
// vtkOrderedTriangulator may create and delete millions of new/delete calls.
// This class allows the overloading of the C++ new operator (or other memory
// allocation requests) by using the method AllocateMemory(). Memory is
// deleted with an invocation of CleanAll() (which deletes ALL memory; any
// given memory allocation cannot be deleted). Note: a block size can be used
// to control the size of each memory allocation. Requests for memory are
// fulfilled from the block until the block runs out, then a new block is
// created.
//
// .SECTION Caveats
// Do not use this class as a general replacement for system memory
// allocation. This class should be used only as a last resort if memory
// leaks cannot be tracked down and eliminated by conventional means. Also,
// deleting memory from vtkHeap is not supported. Only the deletion of
// the entire heap is. (A Reset() method allows you to reuse previously
// allocated memory.)
// .SECTION See Also
// vtkVRMLImporter vtkPLY vtkOrderedTriangulator
#ifndef __vtkHeap_h
#define __vtkHeap_h
#include "vtkObject.h"
class vtkHeapBlock; //forward declaration
class VTK_COMMON_EXPORT vtkHeap : public vtkObject
{
public:
static vtkHeap *New();
vtkTypeMacro(vtkHeap,vtkObject);
void PrintSelf(ostream& os, vtkIndent indent);
// Description:
// Allocate the memory requested.
void* AllocateMemory(size_t n);
// Description:
// Set/Get the size at which blocks are allocated. If a memory
// request is bigger than the block size, then that size
// will be allocated.
virtual void SetBlockSize(size_t);
virtual size_t GetBlockSize() { return this->BlockSize;};
// Description:
// Get the number of allocations thus far.
vtkGetMacro(NumberOfBlocks,int);
vtkGetMacro(NumberOfAllocations,int);
// Description:
// This methods resets the current allocation location
// back to the beginning of the heap. This allows
// reuse of previously allocated memory which may be
// beneficial to performance in many cases.
void Reset();
// Description:
// Convenience method performs string duplication.
char* StringDup(const char* str);
protected:
vtkHeap();
~vtkHeap();
void Add(size_t blockSize);
void CleanAll();
vtkHeapBlock* DeleteAndNext();
size_t BlockSize;
int NumberOfAllocations;
int NumberOfBlocks;
int Alignment;
// Manage the blocks
vtkHeapBlock* First;
vtkHeapBlock* Last;
vtkHeapBlock* Current;
// Manage the memory in the block
size_t Position; //the position in the Current block
private:
vtkHeap(const vtkHeap&); // Not implemented.
void operator=(const vtkHeap&); // Not implemented.
};
#endif
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