diff options
author | Hans Lambermont <hans@lambermont.dyndns.org> | 2002-10-12 15:37:38 +0400 |
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committer | Hans Lambermont <hans@lambermont.dyndns.org> | 2002-10-12 15:37:38 +0400 |
commit | 12315f4d0e0ae993805f141f64cb8c73c5297311 (patch) | |
tree | 59b45827cd8293cfb727758989c7a74b40183974 /source/kernel/gen_system/GEN_SmartPtr.h |
Initial revisionv2.25
Diffstat (limited to 'source/kernel/gen_system/GEN_SmartPtr.h')
-rw-r--r-- | source/kernel/gen_system/GEN_SmartPtr.h | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/source/kernel/gen_system/GEN_SmartPtr.h b/source/kernel/gen_system/GEN_SmartPtr.h new file mode 100644 index 00000000000..535d066be57 --- /dev/null +++ b/source/kernel/gen_system/GEN_SmartPtr.h @@ -0,0 +1,235 @@ +#ifndef NAN_INCLUDED_GEN_SmartPtr_h +#define NAN_INCLUDED_GEN_SmartPtr_h + +/** + * $Id$ + * + * ***** BEGIN GPL/BL DUAL LICENSE BLOCK ***** + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. The Blender + * Foundation also sells licenses for use in proprietary software under + * the Blender License. See http://www.blender.org/BL/ for information + * about this. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV. + * All rights reserved. + * + * The Original Code is: all of this file. + * + * Contributor(s): none yet. + * + * ***** END GPL/BL DUAL LICENSE BLOCK ***** + * + * @author Laurence + */ + +#include <stdlib.h> // for NULL ! + +/** + * @section GEN_SmartPtr + * This class defines a smart pointer similar to that defined in + * the Standard Template Library but without the painful get() + * semantics to access the internal c style pointer. + * + * It is often useful to explicitely decalre ownership of memory + * allocated on the heap within class or function scope. This + * class helps you to encapsulate this ownership within a value + * type. When an instance of this class goes out of scope it + * makes sure that any memory associated with it's internal pointer + * is deleted. It can help to inform users of an aggregate class + * that it owns instances of it's members and these instances + * should not be shared. This is not reliably enforcable in C++ + * but this class attempts to make the 1-1 relationship clear. + * + * @section Example usage + * + * class foo { + * ...constructors accessors etc. + * int x[1000]; + * } + * + * class bar { + * public : + * static + * bar * + * New( + * ) { + * GEN_SmartPtr<foo> afoo = new foo(); + * GEN_SmartPtr<bar> that = new bar(); + * + * if (foo == NULL || that == NULL) return NULL; + * + * that->m_foo = afoo.Release(); + * return that.Release(); + * } + * + * ~bar() { + * // smart ptr takes care of deletion + * } + * private : + * GEN_SmartPtr<foo> m_foo; + * } + * + * You my also safely construct vectors of GEN_SmartPtrs and + * have the vector own stuff you put into it. + * + * e.g. + * { + * std::vector<GEN_SmartPtr<foo> > foo_vector; + * foo_vector.push_back( new foo()); + * foo_vector.push_back( new foo()); + * + * foo_vector[0]->bla(); + * } // foo_vector out of scope => heap memory freed for both foos + * + * @warning this class should only be used for objects created + * on the heap via the new function. It will not behave correctly + * if you pass ptrs to objects created with new[] nor with + * objects declared on the stack. Doing this is likely to crash + * the program or lead to memory leaks. + */ + +template + < class T > +class GEN_SmartPtr { + +public : + + /** + * Construction from reference - this class + * always assumes ownership from the rhs. + */ + + GEN_SmartPtr( + const GEN_SmartPtr &rhs + ){ + m_val = rhs.Release(); + } + + /** + * Construction from ptr - this class always + * assumes that it now owns the memory associated with the + * ptr. + */ + + GEN_SmartPtr( + T* val + ) : + m_val (val) + { + } + + /** + * Defalut constructor + */ + + GEN_SmartPtr( + ) : + m_val (NULL) + { + } + + /** + * Type conversion from this class to the type + * of a pointer to the template parameter. + * This means you can pass an instance of this class + * to a function expecting a ptr of type T. + */ + + operator T * () const { + return m_val; + } + + /** + * Return a reference to the internal ptr class. + * Use with care when you now that the internal ptr + * is not NULL! + */ + + T & + Ref( + ) const { + return *m_val; + } + + /** + * Assignment operator - ownership is transfered from rhs to lhs. + * There is an intenional side-effect of function of transferring + * ownership from the const parameter rhs. This is to insure + * the 1-1 relationship. + * The object associated with this instance is deleted if it + * is not the same as that contained in the rhs. + */ + + GEN_SmartPtr & operator=( + const GEN_SmartPtr &rhs + ) { + if (this->m_val != rhs.m_val) { + delete this->m_val; + } + + this->m_val = rhs.Release(); + return *this; + } + + /** + * Overload the operator -> so that it's possible to access + * all the normal methods of the internal ptr. + */ + + T * operator->() const { + return m_val; + } + + /** + * Caller takes ownership of the object - the object will not + * be deleted when the ptr goes out of scope. + */ + + T * + Release( + ) const { + T* temp = m_val; + (const_cast<GEN_SmartPtr *>(this))->m_val = NULL; + return temp; + } + + /** + * Force destruction of the internal object. + */ + + void + Delete( + ) { + delete (m_val); + m_val = NULL; + } + + /** + * Destructor - deletes object if it exists + */ + + ~GEN_SmartPtr( + ) { + delete (m_val); + } + +private : + + /// The ptr owned by this class. + T * m_val; +}; + +#endif |