1 /* 2 * Copyright 2020 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 #pragma once 17 18 #include <cstdint> 19 #include <type_traits> 20 21 namespace bluetooth { 22 namespace packet { 23 24 template <typename T> 25 class CustomFieldFixedSizeInterface { 26 public: 27 virtual ~CustomFieldFixedSizeInterface() = default; 28 // Get a pointer to a modifiable and readable continuous array of data 29 virtual uint8_t* data() = 0; 30 virtual const uint8_t* data() const = 0; 31 // Get the length of underlying data array, data() + length() would be invalid 32 // subclass T must have kLength variable defined length()33 static constexpr size_t length() { 34 static_assert( 35 std::is_same_v<decltype(T::kLength), const size_t>, "T::kLength must be const size_t or constexpr size_t"); 36 static_assert(std::is_const_v<decltype(T::kLength)>, "T::kLength must be const"); 37 return T::kLength; 38 }; 39 }; 40 41 } // namespace packet 42 } // namespace bluetooth