toml11/toml/from_toml.hpp
2018-05-05 11:59:34 +09:00

70 lines
1.7 KiB
C++

#ifndef TOML11_FROM_TOML
#define TOML11_FROM_TOML
#include "get.hpp"
namespace toml
{
template<typename T>
void from_toml(T& x, const toml::value& v)
{
x = toml::get<T>(v);
return;
}
namespace detail
{
template<typename T>
constexpr toml::value_t determine_castable_type()
{
return check_type<T>() != toml::value_t::Unknown ? check_type<T>() :
toml::detail::is_map<T>::value ? toml::value_t::Table :
toml::detail::is_container<T>::value ? toml::value_t::Array :
toml::value_t::Unknown;
}
template<std::size_t N, typename ... Ts>
struct from_toml_tie_impl
{
constexpr static std::size_t index = sizeof...(Ts) - N;
constexpr static toml::value_t type_index =
determine_castable_type<
typename std::tuple_element<index, std::tuple<Ts...>>::type>();
static void invoke(std::tuple<Ts& ...> tie, const toml::value& v)
{
// static_cast is needed because with intel c++ compiler, operator==
// is only defined when the two types are strictly equal, and type_index
// is const toml::value_t, while v.type() is toml::value_t.
if(static_cast<toml::value_t>(type_index) == v.type())
{
from_toml(std::get<index>(tie), v);
return;
}
return from_toml_tie_impl<N-1, Ts...>::invoke(tie, v);
}
};
template<typename ... Ts>
struct from_toml_tie_impl<0, Ts...>
{
static void invoke(std::tuple<Ts& ...> tie, const toml::value& v)
{
return;
}
};
} // detail
template<typename ... Ts>
void from_toml(std::tuple<Ts& ...> tie, const toml::value& v)
{
detail::from_toml_tie_impl<sizeof...(Ts), Ts...>::invoke(tie, v);
return;
}
} // toml
#endif // TOML11_FROM_TOML