1/*
2 * Copyright (C) 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <type_traits>
29
30namespace WTF {
31
32template<typename> struct EnumTraits;
33
34template<typename E, E...> struct EnumValues;
35
36template<typename T, typename E> struct EnumValueChecker;
37
38template<typename T, typename E, E e, E... es>
39struct EnumValueChecker<T, EnumValues<E, e, es...>> {
40 static constexpr bool isValidEnum(T t)
41 {
42 return (static_cast<T>(e) == t) ? true : EnumValueChecker<T, EnumValues<E, es...>>::isValidEnum(t);
43 }
44};
45
46template<typename T, typename E>
47struct EnumValueChecker<T, EnumValues<E>> {
48 static constexpr bool isValidEnum(T)
49 {
50 return false;
51 }
52};
53
54template<typename E, typename T, std::enable_if_t<std::is_enum<E>::value && !std::is_same<std::underlying_type_t<E>, bool>::value>* = nullptr>
55constexpr bool isValidEnum(T t)
56{
57 static_assert(sizeof(T) >= std::underlying_type_t<E>(), "Integral type must be at least the size of the underlying enum type");
58
59 return EnumValueChecker<T, typename EnumTraits<E>::values>::isValidEnum(t);
60}
61
62template<typename E, typename T, std::enable_if_t<std::is_same<std::underlying_type_t<E>, bool>::value>* = nullptr>
63constexpr bool isValidEnum(T t)
64{
65 return !t || t == 1;
66}
67
68template<typename E>
69constexpr auto enumToUnderlyingType(E e)
70{
71 return static_cast<std::underlying_type_t<E>>(e);
72}
73
74}
75
76using WTF::isValidEnum;
77