enum_name_impl.hpp

/*
MIT License
 
Copyright (c) 2024 mguludag
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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SOFTWARE.
*/
 
#ifndef MGUTILITY_REFLECTION_DETAIL_ENUM_NAME_IMPL_HPP
#define MGUTILITY_REFLECTION_DETAIL_ENUM_NAME_IMPL_HPP
 
#include "enum_for_each.hpp"
#include "mgutility/std/optional.hpp"
#include "mgutility/std/string_view.hpp"
 
#include <algorithm>
#include <array>
 
#if defined(_MSC_VER) && _MSC_VER < 1910
#error "Requires MSVC 2017 or newer!"
#elif defined(__clang__) && __clang_major__ < 6
#error "Requires clang 6 or newer!"
#elif defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 9
#error "Requires gcc 9 or newer!"
#elif !defined(_MSC_VER) && !defined(__clang__) && !defined(__GNUC__)
#error "Your compiler is not supported!"
#endif
 
#ifdef _MSC_VER
#define __PRETTY_FUNCTION__ __FUNCSIG__
#endif
 
namespace mgutility {
namespace detail {
 
struct enum_type {
  template <
      typename Enum, Enum e,
      detail::enable_if_t<!detail::is_scoped_enum<Enum>::value, bool> = true>
  MGUTILITY_CNSTXPR static auto name() noexcept -> mgutility::string_view {
    auto str = mgutility::string_view(__PRETTY_FUNCTION__);
    auto offset = lastidxenumname[0] + lastidxenumname[1];
    auto index = std::max(str.rfind(lastidxenumname[2], str.size() - offset),
                          str.rfind(lastidxenumname[3], str.size() - offset));
    auto result = str.substr(index + 1, str.size() - offset - index);
    return result[0] == '(' ? "" : result;
  }
 
  template <
      typename Enum, Enum e,
      detail::enable_if_t<detail::is_scoped_enum<Enum>::value, bool> = true>
  MGUTILITY_CNSTXPR static auto name() noexcept -> mgutility::string_view {
    auto str = mgutility::string_view(__PRETTY_FUNCTION__);
    auto index =
        str.rfind(lastidxenumname[3], str.size() - lastidxenumname[0]) + 1;
    auto result = str.substr(index, str.size() - lastidxenumname[0] - index);
    return result.size() > 4 && result[4] == lastidxenumname[4] ? "" : result;
  }
 
private:
  static constexpr int lastidxenumname[] =
#if defined(__clang__)
      {1, 1, ' ', ':', '('};
#elif defined(_MSC_VER)
      {21, 0, ',', ':', '<'};
#elif defined(__GNUC__)
      {
#if MGUTILITY_CPLUSPLUS < 201703L
          163,
#else
          157,
#endif
          5, ' ', ':', '('};
#endif
};
 
template <typename Enum, Enum... Is>
MGUTILITY_CNSTXPR inline auto
get_enum_array(detail::enum_sequence<Enum, Is...> /*unused*/) noexcept
    -> std::array<mgutility::string_view, sizeof...(Is) + 1> {
  return std::array<mgutility::string_view, sizeof...(Is) + 1>{
      "", enum_type::template name<Enum, Is>()...};
}
 
template <typename Enum, int Min = mgutility::enum_range<Enum>::min,
          int Max = mgutility::enum_range<Enum>::max>
MGUTILITY_CNSTXPR inline auto get_enum_array() noexcept
    -> std::array<mgutility::string_view, Max - Min + 1> {
  auto array =
      get_enum_array<Enum>(detail::make_enum_sequence<Enum, Min, Max>());
  for (auto &pair : mgutility::custom_enum<Enum>::map) {
    const auto index{(Min < 0 ? -Min : Min) + static_cast<int>(pair.first) + 1};
    (index < Min || index > array.size() - 1)
        ? void()
        : (array[index] = pair.second, void());
  }
  return array;
}
 
template <typename Enum, int Min, int Max>
MGUTILITY_CNSTXPR inline auto to_enum_impl(mgutility::string_view str) noexcept
    -> mgutility::optional<Enum> {
  MGUTILITY_CNSTXPR_CLANG_WA auto arr = get_enum_array<Enum, Min, Max>();
  const auto index{std::find(arr.begin() + 1, arr.end(), str)};
  return index == arr.end() ? mgutility::nullopt
                            : mgutility::optional<Enum>{static_cast<Enum>(
                                  std::distance(arr.begin(), index) + Min - 1)};
}
 
template <typename Enum, int Min, int Max>
MGUTILITY_CNSTXPR auto to_enum_bitmask_impl(mgutility::string_view str) noexcept
    -> mgutility::optional<Enum> {
 
  // Check if the string contains a '|' character
  if (str.find('|') == mgutility::string_view::npos) {
    return to_enum_impl<Enum, Min, Max>(str);
  }
 
  mgutility::optional<Enum> result{mgutility::nullopt};
  std::size_t index = 0;
 
  for (std::size_t i = 0; i < str.size(); ++i) {
    if (str[i] == '|') {
      auto name = str.substr(index, i - index);
      auto maybe_enum = to_enum_impl<Enum, Min, Max>(name);
 
      if (!name.empty() && maybe_enum) {
        result.emplace(result ? static_cast<Enum>(*result | *maybe_enum)
                              : *maybe_enum);
      }
 
      index = i + 1;
    }
  }
 
  auto maybe_enum = to_enum_impl<Enum, Min, Max>(str.substr(index));
  if (result && maybe_enum) {
    result.emplace(static_cast<Enum>(*result | *maybe_enum));
  } else {
    result.reset();
  }
 
  return result;
}
 
template <typename Enum, int Min, int Max,
          detail::enable_if_t<!detail::has_bit_or<Enum>::value, bool> = true>
MGUTILITY_CNSTXPR auto enum_name_impl(Enum e) noexcept
    -> mgutility::string_view {
  MGUTILITY_CNSTXPR auto arr = get_enum_array<Enum, Min, Max>();
  const auto index{(Min < 0 ? -Min : Min) + static_cast<int>(e) + 1};
  return arr[(index < Min || index > arr.size() - 1) ? 0 : index];
}
 
template <typename Enum, int Min, int Max,
          detail::enable_if_t<detail::has_bit_or<Enum>::value, bool> = true>
MGUTILITY_CNSTXPR_CLANG_WA inline auto enum_name_impl(Enum e) noexcept
    -> detail::string_or_view_t<Enum> {
 
  // Get the array of enum names
  MGUTILITY_CNSTXPR_CLANG_WA auto arr = get_enum_array<Enum, Min, Max>();
 
  // Calculate the index in the array
  const auto index = (Min < 0 ? -Min : Min) + static_cast<int>(e) + 1;
  const auto name =
      arr[(index < Min || index >= static_cast<int>(arr.size())) ? 0 : index];
 
  // Lambda to check if a character is a digit
  const auto is_digit = [](char c) { return c >= '0' && c <= '9'; };
 
  // Return the name if it's valid
  if (!name.empty() && !is_digit(name[0])) {
    return std::string{name};
  }
 
  // Construct bitmasked name
  std::string bitmasked_name;
  for (auto i = Min; i < Max; ++i) {
    const auto idx = (Min < 0 ? -Min : Min) + i + 1;
    if (idx >= 0 && idx < static_cast<int>(arr.size()) && !arr[idx].empty() &&
        !is_digit(arr[idx][0]) &&
        (e & static_cast<Enum>(i)) == static_cast<Enum>(i)) {
      bitmasked_name.append(arr[idx]).append("|");
    }
  }
 
  // Remove the trailing '|' if present
  if (!bitmasked_name.empty()) {
    bitmasked_name.pop_back();
  }
 
  if (bitmasked_name.find('|') != std::string::npos) {
    return bitmasked_name;
  }
  return std::string{""};
}
} // namespace detail
} // namespace mgutility
 
#endif // MGUTILITY_REFLECTION_DETAIL_ENUM_NAME_IMPL_HPP