1 /* 2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_UTILITIES_TRAITS_ISDERIVED_HPP 26 #define SHARE_VM_UTILITIES_TRAITS_ISDERIVED_HPP 27 28 #include "memory/allocation.hpp" 29 #include "utilities/traits/isSame.hpp" 30 31 namespace IsDerivedImpl { 32 template <typename DerivedType, typename BaseType> 33 struct Helper: public StackObj { 34 operator BaseType* () const; 35 operator DerivedType* (); 36 }; 37 } 38 39 template <typename DerivedType, typename BaseType> 40 struct IsDerived: AllStatic { 41 typedef char yes[1]; 42 typedef char no[2]; 43 44 template <typename T> 45 static yes& test(DerivedType*, T); 46 static no& test(BaseType*, int); 47 48 enum { 49 value = IsSame<DerivedType, BaseType>::value || sizeof(test(IsDerivedImpl::Helper<DerivedType, BaseType>(), 0)) == sizeof(yes) 50 }; 51 }; 52 53 #endif // SHARE_VM_UTILITIES_TRAITS_ISDERIVED_HPP