1 /*
2  * Copyright (C) 2017 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 <atomic>
20 #include <limits>
21 
22 namespace android {
23 
24 template<typename T>
25 class HandleGenerator {
26   protected:
27     static T getNextHandle();
28 };
29 
30 template<typename T>
getNextHandle()31 T HandleGenerator<T>::getNextHandle() {
32     static std::atomic<uint32_t> mNextUniqueId(1);
33     uint32_t id = mNextUniqueId++;
34     while (id > std::numeric_limits<T>::max()) {
35         id -= std::numeric_limits<T>::max();
36     }
37     return static_cast<T>(id);
38 }
39 
40 }  // namespace android
41