1/*
2 * Copyright (c) 2017, 2019, 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_METAPROGRAMMING_INTEGRALCONSTANT_HPP
26#define SHARE_METAPROGRAMMING_INTEGRALCONSTANT_HPP
27
28
29// An Integral Constant is a class providing a compile-time value of an
30// integral type. An Integral Constant is also a nullary metafunction,
31// returning itself. An integral constant object is implicitly
32// convertible to the associated value.
33//
34// A type n is a model of Integral Constant if it meets the following
35// requirements:
36//
37// n::ValueType : The integral type of n::value
38// n::value : An integral constant expression
39// n::type : IsSame<n::type, n>::value is true
40// n::value_type const c = n() : c == n::value
41
42// A model of the Integer Constant concept.
43// T is an integral type, and is the value_type.
44// v is an integral constant, and is the value.
45template<typename T, T v>
46struct IntegralConstant {
47 typedef T value_type;
48 static const value_type value = v;
49 typedef IntegralConstant<T, v> type;
50 operator value_type() { return value; }
51};
52
53// A bool valued IntegralConstant whose value is true.
54typedef IntegralConstant<bool, true> TrueType;
55
56// A bool valued IntegralConstant whose value is false.
57typedef IntegralConstant<bool, false> FalseType;
58
59#endif // SHARE_METAPROGRAMMING_INTEGRALCONSTANT_HPP
60