Current File : //backups/router/usr/local/include/boost/pfr/detail/core_name20_static.hpp
// Copyright (c) 2023 Bela Schaum, X-Ryl669, Denis Mikhailov.
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// Initial implementation by Bela Schaum, https://github.com/schaumb
// The way to make it union and UB free by X-Ryl669, https://github.com/X-Ryl669
//
#ifndef BOOST_PFR_DETAIL_CORE_NAME20_STATIC_HPP
#define BOOST_PFR_DETAIL_CORE_NAME20_STATIC_HPP
#pragma once
#include <boost/pfr/detail/config.hpp>
#include <boost/pfr/detail/core.hpp>
#include <boost/pfr/detail/sequence_tuple.hpp>
#include <boost/pfr/detail/make_integer_sequence.hpp>
#include <boost/pfr/detail/fields_count.hpp>
#include <boost/pfr/detail/stdarray.hpp>
#include <boost/pfr/detail/fake_object.hpp>
#include <type_traits>
#include <string_view>
#include <array>
#include <memory> // for std::addressof
namespace boost { namespace pfr { namespace detail {
struct core_name_skip {
std::size_t size_at_begin;
std::size_t size_at_end;
bool is_backward;
std::string_view until_runtime;
consteval std::string_view apply(std::string_view sv) const noexcept {
// We use std::min here to make the compiler diagnostic shorter and
// cleaner in case of misconfigured BOOST_PFR_CORE_NAME_PARSING
sv.remove_prefix((std::min)(size_at_begin, sv.size()));
sv.remove_suffix((std::min)(size_at_end, sv.size()));
if (until_runtime.empty()) {
return sv;
}
const auto found = is_backward ? sv.rfind(until_runtime)
: sv.find(until_runtime);
const auto cut_until = found + until_runtime.size();
const auto safe_cut_until = (std::min)(cut_until, sv.size());
return sv.substr(safe_cut_until);
}
};
struct backward {
explicit consteval backward(std::string_view value) noexcept
: value(value)
{}
std::string_view value;
};
consteval core_name_skip make_core_name_skip(std::size_t size_at_begin,
std::size_t size_at_end,
std::string_view until_runtime) noexcept
{
return core_name_skip{size_at_begin, size_at_end, false, until_runtime};
}
consteval core_name_skip make_core_name_skip(std::size_t size_at_begin,
std::size_t size_at_end,
backward until_runtime) noexcept
{
return core_name_skip{size_at_begin, size_at_end, true, until_runtime.value};
}
// it might be compilation failed without this workaround sometimes
// See https://github.com/llvm/llvm-project/issues/41751 for details
template <class>
consteval std::string_view clang_workaround(std::string_view value) noexcept
{
return value;
}
template <class MsvcWorkaround, auto ptr>
consteval auto name_of_field_impl() noexcept {
// Some of the following compiler specific macro may be defined only
// inside the function body:
#ifndef BOOST_PFR_FUNCTION_SIGNATURE
# if defined(__FUNCSIG__)
# define BOOST_PFR_FUNCTION_SIGNATURE __FUNCSIG__
# elif defined(__PRETTY_FUNCTION__) || defined(__GNUC__) || defined(__clang__)
# define BOOST_PFR_FUNCTION_SIGNATURE __PRETTY_FUNCTION__
# else
# define BOOST_PFR_FUNCTION_SIGNATURE ""
# endif
#endif
constexpr std::string_view sv = detail::clang_workaround<MsvcWorkaround>(BOOST_PFR_FUNCTION_SIGNATURE);
static_assert(!sv.empty(),
"====================> Boost.PFR: Field reflection parser configured in a wrong way. "
"Please define the BOOST_PFR_FUNCTION_SIGNATURE to a compiler specific macro, "
"that outputs the whole function signature including non-type template parameters."
);
constexpr auto skip = detail::make_core_name_skip BOOST_PFR_CORE_NAME_PARSING;
static_assert(skip.size_at_begin + skip.size_at_end + skip.until_runtime.size() < sv.size(),
"====================> Boost.PFR: Field reflection parser configured in a wrong way. "
"It attempts to skip more chars than available. "
"Please define BOOST_PFR_CORE_NAME_PARSING to correct values. See documentation section "
"'Limitations and Configuration' for more information."
);
constexpr auto fn = skip.apply(sv);
static_assert(
!fn.empty(),
"====================> Boost.PFR: Extraction of field name is misconfigured for your compiler. "
"It skipped all the input, leaving the field name empty. "
"Please define BOOST_PFR_CORE_NAME_PARSING to correct values. See documentation section "
"'Limitations and Configuration' for more information."
);
auto res = std::array<char, fn.size()+1>{};
auto* out = res.data();
for (auto x: fn) {
*out = x;
++out;
}
return res;
}
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wundefined-var-template"
// clang 16 and earlier don't support address of non-static member as template parameter
// but fortunately it's possible to use C++20 non-type template parameters in another way
// even in clang 16 and more older clangs
// all we need is to wrap pointer into 'clang_wrapper_t' and then pass it into template
template <class T>
struct clang_wrapper_t {
T v;
};
template <class T>
clang_wrapper_t(T) -> clang_wrapper_t<T>;
template <class T>
constexpr auto make_clang_wrapper(const T& arg) noexcept {
return clang_wrapper_t{arg};
}
#else
template <class T>
constexpr const T& make_clang_wrapper(const T& arg) noexcept {
// It's everything OK with address of non-static member as template parameter support on this compiler
// so we don't need a wrapper here, just pass the pointer into template
return arg;
}
#endif
template <class MsvcWorkaround, auto ptr>
consteval auto name_of_field() noexcept {
// Sanity check: known field name must match the deduced one
static_assert(
sizeof(MsvcWorkaround) // do not trigger if `name_of_field()` is not used
&& std::string_view{
detail::name_of_field_impl<
core_name_skip, detail::make_clang_wrapper(std::addressof(
detail::fake_object<core_name_skip>().size_at_begin
))
>().data()
} == "size_at_begin",
"====================> Boost.PFR: Extraction of field name is misconfigured for your compiler. "
"It does not return the proper field name. "
"Please define BOOST_PFR_CORE_NAME_PARSING to correct values. See documentation section "
"'Limitations and Configuration' for more information."
);
return detail::name_of_field_impl<MsvcWorkaround, ptr>();
}
// Storing part of a string literal into an array minimizes the binary size.
//
// Without passing 'T' into 'name_of_field' different fields from different structures might have the same name!
// See https://developercommunity.visualstudio.com/t/__FUNCSIG__-outputs-wrong-value-with-C/10458554 for details
template <class T, std::size_t I>
inline constexpr auto stored_name_of_field = detail::name_of_field<T,
detail::make_clang_wrapper(std::addressof(detail::sequence_tuple::get<I>(
detail::tie_as_tuple(detail::fake_object<T>())
)))
>();
#ifdef __clang__
#pragma clang diagnostic pop
#endif
template <class T, std::size_t... I>
constexpr auto tie_as_names_tuple_impl(std::index_sequence<I...>) noexcept {
return detail::sequence_tuple::make_sequence_tuple(std::string_view{stored_name_of_field<T, I>.data()}...);
}
template <class T, std::size_t I>
constexpr std::string_view get_name() noexcept {
static_assert(
!std::is_union<T>::value,
"====================> Boost.PFR: For safety reasons it is forbidden to reflect unions. See `Reflection of unions` section in the docs for more info."
);
static_assert(
!std::is_array<T>::value,
"====================> Boost.PFR: It is impossible to extract name from old C array since it doesn't have named members"
);
static_assert(
sizeof(T) && BOOST_PFR_USE_CPP17,
"====================> Boost.PFR: Extraction of field's names is allowed only when the BOOST_PFR_USE_CPP17 macro enabled."
);
return stored_name_of_field<T, I>.data();
}
template <class T>
constexpr auto tie_as_names_tuple() noexcept {
static_assert(
!std::is_union<T>::value,
"====================> Boost.PFR: For safety reasons it is forbidden to reflect unions. See `Reflection of unions` section in the docs for more info."
);
static_assert(
!std::is_array<T>::value,
"====================> Boost.PFR: It is impossible to extract name from old C array since it doesn't have named members"
);
static_assert(
sizeof(T) && BOOST_PFR_USE_CPP17,
"====================> Boost.PFR: Extraction of field's names is allowed only when the BOOST_PFR_USE_CPP17 macro enabled."
);
return detail::tie_as_names_tuple_impl<T>(detail::make_index_sequence<detail::fields_count<T>()>{});
}
}}} // namespace boost::pfr::detail
#endif // BOOST_PFR_DETAIL_CORE_NAME20_STATIC_HPP
Mini Shell