1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef NVRAM_MESSAGES_TYPE_TRAITS_H_ 18 #define NVRAM_MESSAGES_TYPE_TRAITS_H_ 19 20 extern "C" { 21 #include <stddef.h> 22 } 23 24 // A subset of utilities similar to what is available in <type_traits>. We have 25 // our own standalone version here since not all target platforms have a full 26 // C++ standard library. 27 28 namespace nvram { 29 30 template <typename T> 31 struct remove_const { 32 using Type = T; 33 }; 34 template <typename T> 35 struct remove_const<const T> { 36 using Type = T; 37 }; 38 39 template <typename T> 40 struct remove_reference { 41 using Type = T; 42 }; 43 template <typename T> 44 struct remove_reference<T&> { 45 using Type = T; 46 }; 47 template <typename T> 48 struct remove_reference<T&&> { 49 using Type = T; 50 }; 51 52 template <bool value, typename T = void> 53 struct enable_if {}; 54 55 template <typename T> 56 struct enable_if<true, T> { 57 using Type = T; 58 }; 59 60 template <typename T, T const_value> 61 struct integral_constant { 62 static constexpr T value = const_value; 63 }; 64 65 using true_type = integral_constant<bool, true>; 66 using false_type = integral_constant<bool, false>; 67 68 template <typename T> 69 T declval(); 70 71 template <size_t... index> 72 struct index_sequence {}; 73 74 template <size_t size, size_t... indices> 75 struct make_index_sequence_builder { 76 using Type = typename make_index_sequence_builder<size - 1, 77 size - 1, 78 indices...>::Type; 79 }; 80 81 template <size_t... indices> 82 struct make_index_sequence_builder<0, indices...> { 83 using Type = index_sequence<indices...>; 84 }; 85 86 template <size_t size> 87 constexpr typename make_index_sequence_builder<size>::Type 88 make_index_sequence(){ 89 return typename make_index_sequence_builder<size>::Type(); 90 }; 91 92 } // namespace nvram 93 94 #endif // NVRAM_MESSAGES_TYPE_TRAITS_H_ 95
