srs/projections/str_cast.hpp

0001 // Boost.Geometry
0002
0003 // Copyright (c) 2018-2023, Oracle and/or its affiliates.
0004 // Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
0005 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0006
0007 // Use, modification and distribution is subject to the Boost Software License,
0008 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010
0011 #ifndef BOOST_GEOMETRY_SRS_PROJECTIONS_STR_CAST_HPP
0012 #define BOOST_GEOMETRY_SRS_PROJECTIONS_STR_CAST_HPP
0013
0014 #include <boost/config.hpp>
0015 #include <boost/geometry/core/exception.hpp>
0016 #include <boost/throw_exception.hpp>
0017 #include <boost/type_traits/remove_cv.hpp>
0018
0019 namespace boost { namespace geometry
0020 {
0021
0022 class bad_str_cast : public geometry::exception
0023 {
0024     char const* what() const noexcept override
0025     {
0026         return "Unable to convert from string.";
0027     }
0028 };
0029
0030 #ifndef DOXYGEN_NO_DETAIL
0031 namespace detail
0032 {
0033
0034 template
0035 <
0036     typename T,
0037     bool IsIntegral = std::is_integral<T>::value,
0038     bool IsSigned = std::is_signed<T>::value
0039 >
0040 struct str_cast_traits_strtox
0041 {
0042     static inline T apply(const char *str, char **str_end)
0043     {
0044         return strtod(str, str_end);
0045     }
0046 };
0047
0048 template <typename T>
0049 struct str_cast_traits_strtox<T, true, true>
0050 {
0051     static inline T apply(const char *str, char **str_end)
0052     {
0053         return strtol(str, str_end, 0);
0054     }
0055 };
0056
0057 template <typename T>
0058 struct str_cast_traits_strtox<T, true, false>
0059 {
0060     static inline T apply(const char *str, char **str_end)
0061     {
0062         return strtoul(str, str_end, 0);
0063     }
0064 };
0065
0066 template <typename T>
0067 struct str_cast_traits_strtox<T, false, false>
0068 {
0069     static inline T apply(const char *str, char **str_end)
0070     {
0071         return strtod(str, str_end);
0072     }
0073 };
0074
0075 template <>
0076 struct str_cast_traits_strtox<long long, true, true>
0077 {
0078     static inline long long apply(const char *str, char **str_end)
0079     {
0080         return strtoll(str, str_end, 0);
0081     }
0082 };
0083
0084 template <>
0085 struct str_cast_traits_strtox<unsigned long long, true, false>
0086 {
0087     static inline unsigned long long apply(const char *str, char **str_end)
0088     {
0089         return strtoull(str, str_end, 0);
0090     }
0091 };
0092
0093 template <>
0094 struct str_cast_traits_strtox<float, false, false>
0095 {
0096     static inline float apply(const char *str, char **str_end)
0097     {
0098         return strtof(str, str_end);
0099     }
0100 };
0101
0102 template <>
0103 struct str_cast_traits_strtox<long double, false, false>
0104 {
0105     static inline long double apply(const char *str, char **str_end)
0106     {
0107         return strtold(str, str_end);
0108     }
0109 };
0110
0111 template <typename T>
0112 struct str_cast_traits_generic
0113 {
0114     static inline T apply(const char *str)
0115     {
0116         char * str_end = (char*)(void*)str;
0117         T res = str_cast_traits_strtox
0118                     <
0119                         typename boost::remove_cv<T>::type
0120                     >::apply(str, &str_end);
0121         if (str_end == str)
0122         {
0123             BOOST_THROW_EXCEPTION( bad_str_cast() );
0124         }
0125         return res;
0126     }
0127 };
0128
0129 } // namespace detail
0130 #endif // DOXYGEN_NO_DETAIL
0131
0132 template <typename T>
0133 struct str_cast_traits
0134 {
0135     template <typename String>
0136     static inline T apply(String const& str)
0137     {
0138         return detail::str_cast_traits_generic<T>::apply(str.c_str());
0139     }
0140 };
0141
0142 template <typename T, typename String>
0143 inline T str_cast(String const& str)
0144 {
0145     return str_cast_traits<T>::apply(str);
0146 }
0147
0148
0149 }} // namespace boost::geometry
0150
0151 #endif // BOOST_GEOMETRY_SRS_PROJECTIONS_STR_CAST_HPP