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48 lines
1.9 KiB
C++
48 lines
1.9 KiB
C++
/*
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* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#ifndef SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP
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#define SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP
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#include "memory/allocation.hpp"
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// This metaprogramming tool allows explicitly enabling and disabling overloads
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// of member functions depending on whether the condition B holds true.
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// For example typename EnableIf<IsPointer<T>::value>::type func(T ptr) would
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// only become an overload the compiler chooses from if the type T is a pointer.
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// If it is not, then the template definition is not expanded and there will be
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// no compiler error if there is another overload of func that is selected when
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// T is not a pointer. Like for example
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// typename EnableIf<!IsPointer<T>::value>::type func(T not_ptr)
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template <bool B, typename T = void>
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struct EnableIf: AllStatic {};
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template <typename T>
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struct EnableIf<true, T>: AllStatic {
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typedef T type;
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};
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#endif // SHARE_VM_METAPROGRAMMING_ENABLEIF_HPP
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