1 // Copyright 2021 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <array> 17 #include <cstddef> 18 #include <type_traits> 19 #include <utility> 20 21 namespace pw { 22 namespace containers { 23 24 // If std::to_array is available, use it as pw::containers::to_array. 25 #ifdef __cpp_lib_to_array 26 27 using std::to_array; 28 29 #else 30 31 namespace impl { 32 33 template <typename T, size_t kSize, size_t... kIndices> 34 constexpr std::array<std::remove_cv_t<T>, kSize> CopyArray( 35 const T (&values)[kSize], std::index_sequence<kIndices...>) { 36 return {{values[kIndices]...}}; 37 } 38 39 template <typename T, size_t kSize, size_t... kIndices> 40 constexpr std::array<std::remove_cv_t<T>, kSize> MoveArray( 41 T (&&values)[kSize], std::index_sequence<kIndices...>) { 42 return {{std::move(values[kIndices])...}}; 43 } 44 45 } // namespace impl 46 47 // If C++20's std::to_array is not available, implement pw::containers::to_array 48 // in a C++14-compatible way. 49 template <typename T, size_t kSize> 50 constexpr std::array<std::remove_cv_t<T>, kSize> to_array(T (&values)[kSize]) { 51 return impl::CopyArray(values, std::make_index_sequence<kSize>{}); 52 } 53 54 template <typename T, size_t kSize> 55 constexpr std::array<std::remove_cv_t<T>, kSize> to_array(T (&&values)[kSize]) { 56 return impl::MoveArray(std::move(values), std::make_index_sequence<kSize>{}); 57 } 58 59 #endif // __cpp_lib_to_array 60 61 } // namespace containers 62 } // namespace pw 63