1 /* 2 // Copyright (c) 2018 Intel Corporation 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 #include <boost/type_index.hpp> 19 20 #include <stdexcept> 21 #include <string> 22 23 namespace details 24 { 25 26 template <typename U> 27 struct VariantToNumericVisitor 28 { 29 template <typename T> operator ()details::VariantToNumericVisitor30 U operator()(const T& t) const 31 { 32 if constexpr (std::is_arithmetic_v<T>) 33 { 34 return static_cast<U>(t); 35 } 36 throw std::invalid_argument( 37 "Cannot translate type " + 38 boost::typeindex::type_id<T>().pretty_name() + " to " + 39 boost::typeindex::type_id<U>().pretty_name()); 40 } 41 }; 42 43 } // namespace details 44 45 using VariantToFloatVisitor = details::VariantToNumericVisitor<float>; 46 using VariantToIntVisitor = details::VariantToNumericVisitor<int>; 47 using VariantToUnsignedIntVisitor = 48 details::VariantToNumericVisitor<unsigned int>; 49 using VariantToDoubleVisitor = details::VariantToNumericVisitor<double>; 50 51 struct VariantToStringVisitor 52 { 53 template <typename T> operator ()VariantToStringVisitor54 std::string operator()(const T& t) const 55 { 56 if constexpr (std::is_same_v<T, std::string>) 57 { 58 return t; 59 } 60 else if constexpr (std::is_arithmetic_v<T>) 61 { 62 return std::to_string(t); 63 } 64 throw std::invalid_argument( 65 "Cannot translate type " + 66 boost::typeindex::type_id<T>().pretty_name() + " to string"); 67 } 68 }; 69