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 #ifndef UTIL_CHRE_NESTED_DATA_PTR_H_
18 #define UTIL_CHRE_NESTED_DATA_PTR_H_
19 
20 namespace chre {
21 
22 /**
23  * A template that provides the ability to store data inside of a void pointer
24  * to avoid allocating space on the heap in the case where the data is smaller
25  * than the size of a void pointer.
26  */
27 template<typename DataType>
28 union NestedDataPtr {
NestedDataPtr()29   NestedDataPtr() {
30     static_assert(sizeof(NestedDataPtr<DataType>) == sizeof(void *),
31                   "Size of NestedDataPtr must be equal to that of void *");
32   }
33   void *dataPtr;
34   DataType data;
35 };
36 
37 }  // namespace chre
38 
39 #endif  // UTIL_CHRE_NESTED_DATA_PTR_H_