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/*
@file
Defines `boost::hana::experimental::type_name`.
@copyright Louis Dionne 2013-2017
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_HANA_EXPERIMENTAL_TYPE_NAME_HPP
#define BOOST_HANA_EXPERIMENTAL_TYPE_NAME_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/string.hpp>
#include <cstddef>
#include <utility>
BOOST_HANA_NAMESPACE_BEGIN namespace experimental {
namespace detail {
struct cstring {
char const* ptr;
std::size_t length;
};
// Note: We substract the null terminator from the string sizes below.
template <typename T>
constexpr cstring type_name_impl2() {
#if defined(__clang__)
constexpr char const* pretty_function = __PRETTY_FUNCTION__;
constexpr std::size_t total_size = sizeof(__PRETTY_FUNCTION__) - 1;
constexpr std::size_t prefix_size = sizeof("boost::hana::experimental::detail::cstring boost::hana::experimental::detail::type_name_impl2() [T = ") - 1;
constexpr std::size_t suffix_size = sizeof("]") - 1;
#else
#error "No support for this compiler."
#endif
return {pretty_function + prefix_size, total_size - prefix_size - suffix_size};
}
template <typename T, std::size_t ...i>
auto type_name_impl1(std::index_sequence<i...>) {
constexpr auto name = detail::type_name_impl2<T>();
return hana::string<*(name.ptr + i)...>{};
}
} // end namespace detail
//! @ingroup group-experimental
//! Returns a `hana::string` representing the name of the given type, at
//! compile-time.
//!
//! This only works on Clang (and apparently MSVC, but Hana does not work
//! there as of writing this). Original idea taken from
//! https://github.com/Manu343726/ctti.
template <typename T>
auto type_name() {
constexpr auto name = detail::type_name_impl2<T>();
return detail::type_name_impl1<T>(std::make_index_sequence<name.length>{});
}
} BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_EXPERIMENTAL_TYPE_NAME_HPP
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