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/*========================================================================= |
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Program: Insight Segmentation & Registration Toolkit |
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Module: $RCSfile: itkObjectStore.h.html,v $ |
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Language: C++ |
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Date: $Date: 2006/01/17 19:15:43 $ |
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Version: $Revision: 1.4 $ |
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Copyright (c) Insight Software Consortium. All rights reserved. |
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See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details. |
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This software is distributed WITHOUT ANY WARRANTY; without even |
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the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
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PURPOSE. See the above copyright notices for more information. |
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=========================================================================*/ |
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#ifndef __itkObjectStore_h |
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#define __itkObjectStore_h |
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#include "itkObjectFactory.h" |
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#include "itkObject.h" |
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#include <vector> |
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namespace itk { |
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/** \class ObjectStore |
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* \brief A specialized memory management object for allocating and destroying |
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* contiguous blocks of objects. |
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* |
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* ObjectStore implements a dynamically sizeable free memory store, from which |
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* instantiated objects can be borrowed and returned without always invoking |
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* calls to new/delete. This type of memory management is useful in situations |
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* where calls to new/delete may be expensive, such as a multithreaded |
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* environment to avoid the heap contention problem. |
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* |
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* ObjectStore is designed to grow dynamically. Shrinking is a more difficult |
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* problem and is only done if it will not invalidate any pointers that have |
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* been "lent" to a calling application. |
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* |
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* This implementation uses a very simple, list-based scheme to manage |
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* pointers that have been borrowed and returned. Memory overhead incurred is |
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* one pointer per object allocated. Because of this overhead, ObjectStore is |
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* not efficient for use with small objects such as native types. |
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* |
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* Important notes on thread-safety: This object is thread-safe in the same |
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* sense that STL defines thread-safety: simultaneous operations on distinct |
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* containers are safe. It is the user's responsibility to apply appropriate |
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* mutex locks if the same container is used across multiple threads. One (or |
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* more) ObjectStore's can be safely be created for each thread -- and may even |
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* be more efficient in terms of memory use than sharing a single ObjectStore |
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* across threads. Calls to \em{new} and \em{delete} have been placed in |
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* critical sections in case a compiler's implementation of new/delete is not |
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* thread-safe. |
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* |
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* Warnings: For efficiency reasons, the ObjectStore does not guard against the |
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* same pointer being Returned() more than once. Doing this could result in |
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* serious problems. |
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*/ |
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template < class TObjectType > |
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class ITK_EXPORT ObjectStore : public Object |
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{ |
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public: |
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***/** Standard typedefs. */ |
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typedef ObjectStore Self; |
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TDA |
typedef Object Superclass; |
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TDA |
typedef SmartPointer<Self> Pointer; |
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TDA |
typedef SmartPointer<const Self> ConstPointer; |
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/** Method for creation through the object factory. */ |
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itkNewMacro(Self); |
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/** Run-time type information (and related methods). */ |
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itkTypeMacro(ObjectStore, Object); |
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/** Type of the objects in storage. */ |
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typedef TObjectType ObjectType; |
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/** Type of list for storing pointers to free memory.*/ |
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typedef std::vector<ObjectType *> FreeListType; |
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/** Type of memory allocation strategy */ |
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typedef enum {LINEAR_GROWTH = 0, EXPONENTIAL_GROWTH = 1} GrowthStrategyType; |
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/** Borrow a pointer to an object from the memory store. */ |
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ObjectType *Borrow(); |
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/** Return a pointer to the memory store for reuse. WARNING: The ObjectStore |
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* assumes a pointer is returned exactly once after each time it has been |
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* borrowed. */ |
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void Return(ObjectType *p); |
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/** Returns the size of the container. This is not the number of objects |
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* available, but the total number of objects allocated. */ |
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itkGetMacro(Size, ::size_t); |
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/** Ensures that there are at least n elements allocated in the storage |
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* container. Will not shrink the container, but may enlarge the |
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* container. */ |
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void Reserve(::size_t n); |
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/** Attempts to free memory that is not in use and shrink the size of the |
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* container. Not guaranteed to do anything. */ |
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void Squeeze(); |
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/** Frees all memory in the container */ |
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void Clear(); |
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/** Set/Get the linear growth size */ |
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itkSetMacro(LinearGrowthSize, ::size_t); |
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itkGetMacro(LinearGrowthSize, ::size_t); |
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/** Set/Get the growth strategy. */ |
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itkSetMacro(GrowthStrategy, GrowthStrategyType); |
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itkGetMacro(GrowthStrategy, GrowthStrategyType); |
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/** Set growth strategy to exponential */ |
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void SetGrowthStrategyToExponential() |
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**{ this->SetGrowthStrategy(EXPONENTIAL_GROWTH); } |
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/** Set growth strategy to linear */ |
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void SetGrowthStrategyToLinear() |
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**{ this->SetGrowthStrategy(LINEAR_GROWTH); } |
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protected: |
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ObjectStore(); |
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~ObjectStore(); |
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virtual void PrintSelf(std::ostream& os, Indent indent) const; |
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/** Returns a new size to grow. */ |
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::size_t GetGrowthSize(); |
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struct MemoryBlock |
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**{ |
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MemoryBlock(): Size(0), Begin(0) {} |
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MemoryBlock(::size_t n) : Size(n) |
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****{ Begin = new ObjectType[n]; } |
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~MemoryBlock() { } // Purposely does *not* free memory |
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void Delete() |
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****{ if (Begin !=0) delete[] Begin; } |
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ObjectType *Begin; |
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::size_t Size; |
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**}; |
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private: |
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ObjectStore(const Self&); //purposely not implemented |
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void operator=(const Self&); //purposely not implemented |
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GrowthStrategyType m_GrowthStrategy; |
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::size_t m_Size; |
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::size_t m_LinearGrowthSize; |
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/** Pointers to objects available for borrowing. */ |
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FreeListType m_FreeList; |
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/** A list of MemoryBlocks that have been allocated. */ |
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std::vector<MemoryBlock> m_Store; |
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}; |
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} // end namespace itk |
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#ifndef ITK_MANUAL_INSTANTIATION |
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#include "itkObjectStore.txx" |
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#endif |
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#endif |
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