mirror of https://gitee.com/openkylin/gdcm.git
106 lines
3.0 KiB
C++
106 lines
3.0 KiB
C++
/*=========================================================================
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Program: GDCM (Grassroots DICOM). A DICOM library
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Copyright (c) 2006-2011 Mathieu Malaterre
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All rights reserved.
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See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html 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 notice for more information.
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=========================================================================*/
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#ifndef GDCMOBJECT_H
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#define GDCMOBJECT_H
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#include "gdcmTypes.h"
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#include <assert.h>
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#include <iostream> // grrrr
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//namespace std { class ostream; }
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namespace gdcm
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{
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template<class ObjectType> class SmartPointer;
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/**
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* \brief Object
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*
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* \note main superclass for object that want to use SmartPointer
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* invasive ref counting system
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*
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* \see SmartPointer
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*/
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class GDCM_EXPORT Object
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{
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template <class ObjectType> friend class SmartPointer;
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friend std::ostream& operator<<(std::ostream &os, const Object &obj);
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public:
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Object():ReferenceCount(0) {}
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// Implementation note:
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// If I move ~Object in the protected section I can prevent people
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// from writing:
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// SmartPointer<Object> p = new Object;
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// delete p; // due to SmartPointer::operator ObjectType * () const
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// but on the other hand one could not define an Object on the stack
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// Object obj;
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// Furthermore it would not prevent anyone from doing:
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// class MyObject : public Object {};
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// SmartPointer<MyObject> o = new MyObject;
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// delete o; // grrrrrr
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virtual ~Object() {
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// If your debugger reach here it means you are doing something silly
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// like using SmartPointer on object allocated on the stack (vs heap)
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assert(ReferenceCount == 0);
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}
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// http://www.parashift.com/c++-faq-lite/freestore-mgmt.html#faq-16.24
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// Set the ref count to 0
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// Do NOT copy the reference count !
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/// Special requirement for copy/cstor, assignment operator
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Object(const Object&):ReferenceCount(0){}
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void operator=(const Object&){}
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//static Object* New() { return new Object; }
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protected:
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// For the purpose of the invasive SmartPointer implementation
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void Register() {
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ReferenceCount++;
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assert( ReferenceCount > 0 );
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}
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void UnRegister() {
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assert( ReferenceCount > 0 );
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ReferenceCount--;
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if(!ReferenceCount)
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{
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delete this;
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}
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}
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public:
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// For dealing with printing of object and polymorphism
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virtual void Print(std::ostream &) const {}
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private:
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long ReferenceCount;
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};
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//----------------------------------------------------------------------------
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// function do not carry vtable. Thus define in the base class the operator
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// and use the member function ->Print() to call the appropriate function
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// NOTE: All subclass of Object needs to implement the Print function
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inline std::ostream& operator<<(std::ostream &os, const Object &obj)
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{
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obj.Print(os);
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return os;
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}
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} // end namespace gdcm
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#endif //GDCMOBJECT_H
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