ITK  4.1.0
Insight Segmentation and Registration Toolkit
itkAutoPointer.h
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00001 /*=========================================================================
00002  *
00003  *  Copyright Insight Software Consortium
00004  *
00005  *  Licensed under the Apache License, Version 2.0 (the "License");
00006  *  you may not use this file except in compliance with the License.
00007  *  You may obtain a copy of the License at
00008  *
00009  *         http://www.apache.org/licenses/LICENSE-2.0.txt
00010  *
00011  *  Unless required by applicable law or agreed to in writing, software
00012  *  distributed under the License is distributed on an "AS IS" BASIS,
00013  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  *  See the License for the specific language governing permissions and
00015  *  limitations under the License.
00016  *
00017  *=========================================================================*/
00018 #ifndef __itkAutoPointer_h
00019 #define __itkAutoPointer_h
00020 
00021 #include "itkMacro.h"
00022 #include <iostream>
00023 
00024 namespace itk
00025 {
00045 template< class TObjectType >
00046 class ITK_EXPORT AutoPointer
00047 {
00048 public:
00050   typedef TObjectType ObjectType;
00051   typedef AutoPointer Self;
00052 
00054   AutoPointer ():m_Pointer(0), m_IsOwner(false)
00055   {}
00056 
00058   explicit AutoPointer (AutoPointer & p)
00059   {
00060     m_IsOwner = p.IsOwner();          // Ownership can only be taken from
00061                                       // another owner
00062     m_Pointer = p.ReleaseOwnership(); // release ownership if appropriate
00063   }
00065 
00067   explicit AutoPointer (ObjectType *p, bool takeOwnership):
00068     m_Pointer(p), m_IsOwner(takeOwnership)
00069   {}
00070 
00072   ~AutoPointer ()
00073   {
00074     if ( m_IsOwner && m_Pointer )
00075       {
00076       delete m_Pointer;
00077       }
00078     m_Pointer = 0;
00079     m_IsOwner = false;
00080   }
00082 
00084   ObjectType * operator->() const
00085   { return m_Pointer; }
00086 
00089   void Reset(void)
00090   {
00091     if ( m_IsOwner && m_Pointer )
00092       {
00093       delete m_Pointer;
00094       }
00095     m_Pointer = 0;
00096     m_IsOwner = false;
00097   }
00099 
00101   void TakeOwnership(void)
00102   { m_IsOwner = true; }
00103 
00105   void TakeOwnership(ObjectType *objectptr)
00106   {
00107     if ( m_IsOwner && m_Pointer )
00108       {
00109       delete m_Pointer; // remove the current one
00110       }
00111     m_Pointer = objectptr;
00112     m_IsOwner = true;
00113   }
00115 
00117   void TakeNoOwnership(ObjectType *objectptr)
00118   {
00119     if ( m_IsOwner && m_Pointer )
00120       {
00121       delete m_Pointer; // remove the current one
00122       }
00123     m_Pointer = objectptr;
00124     m_IsOwner = false;
00125   }
00127 
00129   bool IsOwner(void) const
00130   { return m_IsOwner; }
00131 
00144   ObjectType * ReleaseOwnership(void)
00145   {
00146     m_IsOwner = false;
00147     return m_Pointer;
00148   }
00150 
00152   ObjectType * GetPointer() const
00153   { return m_Pointer; }
00154 
00156   bool operator==(const AutoPointer & r) const
00157   { return (void *)m_Pointer == (void *)r.m_Pointer; }
00158 
00160   bool operator!=(const AutoPointer & r) const
00161   { return (void *)m_Pointer != (void *)r.m_Pointer; }
00162 
00164   bool operator<(const AutoPointer & r) const
00165   { return (void *)m_Pointer < (void *)r.m_Pointer; }
00166 
00168   bool operator>(const AutoPointer & r) const
00169   { return (void *)m_Pointer > (void *)r.m_Pointer; }
00170 
00172   bool operator<=(const AutoPointer & r) const
00173   { return (void *)m_Pointer <= (void *)r.m_Pointer; }
00174 
00176   bool operator>=(const AutoPointer & r) const
00177   { return (void *)m_Pointer >= (void *)r.m_Pointer; }
00178 
00180   AutoPointer & operator=(AutoPointer & r)
00181   {
00182     AutoPointer(r).Swap(*this);
00183     return *this;
00184   }
00186 
00189   operator bool() const
00190                 { return ( m_Pointer != NULL ); }
00191 
00193 /*  ObjectType *Print (std::ostream& os) const
00194     {
00195     // This prints the object pointed to by the pointer
00196     (*m_Pointer).Print(os);
00197     os << "Owner: " << m_IsOwner << std::endl;
00198     return m_Pointer;
00199     }
00200 */
00201 private:
00203 
00205   void Swap(AutoPointer & r)
00206   throw( )
00207   {
00208     ObjectType *temp = m_Pointer;
00209 
00210     m_Pointer         = r.m_Pointer;
00211     r.m_Pointer       = temp;
00212   }
00213 
00215   ObjectType *m_Pointer;
00216   bool        m_IsOwner;
00217 };
00218 
00219 template< typename T >
00220 std::ostream & operator<<(std::ostream & os, AutoPointer< T > p)
00221 {
00222   p.Print(os);
00223   os << "Owner: " << p.IsOwner() << std::endl;
00224   return os;
00225 }
00226 
00229 template< typename TAutoPointerBase, typename TAutoPointerDerived >
00230 void
00231 ITK_EXPORT TransferAutoPointer(TAutoPointerBase & pa, TAutoPointerDerived & pb)
00232 {
00233   // give a chance to natural polymorphism
00234   pa.TakeNoOwnership( pb.GetPointer() );
00235   if ( pb.IsOwner() )
00236     {
00237     pa.TakeOwnership();      // pa Take Ownership
00238     pb.ReleaseOwnership();   // pb Release Ownership and clears
00239     }
00240 }
00241 } // end namespace itk
00243 
00244 #endif
00245