1 /*
2  * Copyright (C) 2019 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 #pragma once
18 
19 #include <iterator>
20 #include <type_traits>
21 
22 namespace android {
23 
24 namespace internal {
25 
26 // Never instantiated. Used as a placeholder for template variables.
27 template <typename T>
28 struct invalid_type;
29 
30 // AIDL generates specializations of this for enums.
31 template <typename EnumType, typename = std::enable_if_t<std::is_enum<EnumType>::value>>
32 constexpr invalid_type<EnumType> enum_values;
33 } // namespace internal
34 
35 // Usage: for (const auto v : enum_range<EnumType>() ) { ... }
36 template <typename EnumType, typename = std::enable_if_t<std::is_enum<EnumType>::value>>
37 struct enum_range {
beginenum_range38     constexpr auto begin() const { return std::begin(internal::enum_values<EnumType>); }
endenum_range39     constexpr auto end() const { return std::end(internal::enum_values<EnumType>); }
40 };
41 
42 } // namespace android
43