103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
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// Copyright (c) 1999
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/STL_Extension/include/CGAL/Handle.h $
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// $Id: Handle.h 8b474dd 2020-05-20T10:32:03+02:00 Laurent Rineau
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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//
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// Author(s) : Sylvain Pion
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#ifndef CGAL_HANDLE_H
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#define CGAL_HANDLE_H
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#include <cstddef>
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#include <CGAL/Handle_for.h>
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#include <CGAL/assertions.h>
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namespace CGAL {
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class Rep
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{
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friend class Handle;
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protected:
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Rep() { count = 1; }
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virtual ~Rep() {}
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int count;
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};
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class Handle
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{
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public:
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typedef std::ptrdiff_t Id_type ;
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Handle() noexcept
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: PTR(static_cast<Rep*>(0)) {}
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// FIXME: if the precondition throws in a noexcept function, the program terminates
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Handle(const Handle& x) noexcept
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{
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CGAL_precondition( x.PTR != static_cast<Rep*>(0) );
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PTR = x.PTR;
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CGAL_assume (PTR->count > 0);
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PTR->count++;
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}
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~Handle()
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{
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if ( PTR && (--PTR->count == 0))
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delete PTR;
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}
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Handle&
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operator=(const Handle& x) noexcept
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{
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CGAL_precondition( x.PTR != static_cast<Rep*>(0) );
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x.PTR->count++;
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if ( PTR && (--PTR->count == 0))
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delete PTR;
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PTR = x.PTR;
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return *this;
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}
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friend void swap(Handle& a, Handle& b) noexcept { std::swap(a.PTR, b.PTR); }
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void reset()
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{
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if (PTR)
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{
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if (--PTR->count==0)
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delete PTR;
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PTR=0;
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}
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}
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int
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refs() const noexcept { return PTR->count; }
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Id_type id() const noexcept { return PTR - static_cast<Rep*>(0); }
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bool identical(const Handle& h) const noexcept { return PTR == h.PTR; }
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void * for_compact_container() const { return PTR; }
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void for_compact_container(void* p) { PTR = static_cast<Rep*>(p); }
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protected:
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Rep* PTR;
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};
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//inline Handle::Id_type id(const Handle& x) { return x.id() ; }
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inline bool identical(const Handle &h1, const Handle &h2) noexcept { return h1.identical(h2); }
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} //namespace CGAL
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#endif // CGAL_HANDLE_H
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