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.
 
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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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
 
// NOLINTNEXTLINE [unused-includes]
#include "enum_for_each.hpp"
#include "meta.hpp"
#include "mgutility/_common/definitions.hpp"
#include "mgutility/std/fixed_string.hpp"
#include "mgutility/std/optional.hpp"
#include "mgutility/std/string_view.hpp"
#include "mgutility/std/utility.hpp"
 
#include <algorithm>
#include <array>
#include <cstddef>
#include <cstring>
 
#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
 
// NOLINTNEXTLINE [modernize-concat-nested-namespaces]
namespace mgutility {
namespace detail {
 
#ifndef MGUTILITY_STRLEN
// NOLINTNEXTLINE [cppcoreguidelines-macro-usage]
#define MGUTILITY_STRLEN(x) sizeof(x) - 1
#endif
 
template <typename U, int Min, int Max> struct enum_name_parse_result {
  static constexpr auto size = std::size_t{Max - Min};
  fixed_string<MGUTILITY_GLOBAL_ENUM_BLOB_SIZE> strings;
  std::array<pair<std::size_t, std::size_t>, size> ranges;
};
 
template <typename T, int Min, int Max>
using enum_name_array =
    std::array<mgutility::string_view, static_cast<std::size_t>(Max - Min)>;
 
struct enum_type {
private:
  template <typename Enum, Enum... e>
  MGUTILITY_CNSTXPR static auto
  raw_name(detail::enum_sequence<Enum, e...> /*unused*/) noexcept
      -> mgutility::string_view {
#if defined(__GNUC__) && !defined(__clang__) && MGUTILITY_CPLUSPLUS >= 201402L
#define PREFIX                                                                 \
  MGUTILITY_STRLEN("static constexpr mgutility::string_view "                  \
                   "mgutility::detail::enum_type::raw_name(mgutility::detail:" \
                   ":enum_sequence<Enum, e ...>) [with Enum = ")
#elif defined(__clang__) || defined(__GNUC__)
#define PREFIX                                                                 \
  MGUTILITY_STRLEN("static mgutility::string_view "                            \
                   "mgutility::detail::enum_type::raw_name(mgutility::detail:" \
                   ":enum_sequence<Enum, e ...>) [with Enum = ")
#elif defined(_MSC_VER)
#if MGUTILITY_CPLUSPLUS > 201402L
#define PREFIX                                                                 \
  MGUTILITY_STRLEN(                                                            \
      "class std::basic_string_view<char,struct std::char_traits<char> > "     \
      "__cdecl mgutility::detail::enum_type::raw_name")
#else
#define PREFIX                                                                 \
  MGUTILITY_STRLEN("class mgutility::basic_string_view<char> __cdecl "         \
                   "mgutility::detail::enum_type::raw_name")
#endif
#else
#define PREFIX 0
#endif
 
    return mgutility::string_view(__PRETTY_FUNCTION__ + PREFIX,
                                  MGUTILITY_STRLEN(__PRETTY_FUNCTION__) -
                                      PREFIX + 1);
  }
 
  template <typename Enum, int Min, int Max>
  MGUTILITY_CNSTXPR static auto parse() noexcept
      -> enum_name_parse_result<detail::underlying_type_t<Enum>, Min, Max> {
    using U = detail::underlying_type_t<Enum>;
    using result_type = enum_name_parse_result<U, Min, Max>;
 
    MGUTILITY_CNSTXPR auto str =
        raw_name<Enum>(detail::make_enum_sequence<Enum, Min, Max>{});
 
#if defined(__clang__) || defined(__GNUC__)
#if defined(__clang__)
    auto end = str.rfind(']');
#elif defined(__GNUC__) && !defined(__clang__)
    auto end = str.rfind(';');
#endif
 
    auto enum_names = str.substr(0, end);
 
#elif defined(_MSC_VER)
    // MSVC: different format
    auto pos = str.find(',');
    if (pos == mgutility::string_view::npos)
      return {};
 
    ++pos;
 
    auto end = str.rfind('>');
    auto enum_names = str.substr(pos, end - pos);
 
#else
    return {};
#endif
 
    if (enum_names.empty()) {
      return {};
    }
 
    result_type result{};
 
    std::size_t idx = 0;
 
    while (!enum_names.empty() && idx < result.ranges.size()) {
      auto pos = enum_names.find(',');
      if (pos != mgutility::string_view::npos) {
        auto token = enum_names.substr(0, pos);
 
        // remove whitespace
        while (!token.empty() && token.front() == ' ') {
          token = token.substr(1);
        }
 
        while (!token.empty() && token.back() == ' ') {
          token = token.substr(0, token.size() - 1);
        }
 
        std::size_t begin = token.find('(');
        std::size_t end = token.rfind(')');
        if (begin != mgutility::string_view::npos ||
            end != mgutility::string_view::npos) {
          result.ranges[idx++] = {0, 0};
          enum_names = enum_names.substr(pos + 1);
          continue;
        }
 
        std::size_t start = 0;
        if (token.find(':') != mgutility::string_view::npos) {
          start = token.find(':') + 2;
          token = token.substr(start);
        }
 
        // Write into the fixed-size global buffer
        auto offset = result.strings.size();
        result.strings.append(token);
        result.ranges[idx++] = {offset, token.size()};
 
        enum_names = enum_names.substr(pos + 1);
        continue;
      }
      enum_names = {};
    }
 
    return result;
  }
 
public:
  template <typename Enum, int Min, int Max>
  MGUTILITY_CNSTXPR static auto name() noexcept
      -> enum_name_parse_result<detail::underlying_type_t<Enum>, Min, Max> {
    return parse<Enum, Min, Max>();
  }
};
 
template <typename Enum, int Min, int Max> struct enum_array_cache;
 
template <typename Enum, int Min, int Max> struct enum_array_cache {
  using underlying = detail::underlying_type_t<Enum>;
  using parse_result_t = enum_name_parse_result<underlying, Min, Max>;
 
#if MGUTILITY_CPLUSPLUS > 201402L
 
  static constexpr auto parse_result =
      enum_type::template name<Enum, Min, Max>();
 
#else
  // C++11: lazy runtime array
  static parse_result_t &value() {
    static parse_result_t arr = enum_type::template name<Enum, Min, Max>();
 
    return arr;
  }
#endif
 
  static MGUTILITY_CNSTXPR auto
  apply_custom(const parse_result_t &result) noexcept
      -> enum_name_array<Enum, Min, Max> {
    enum_name_array<Enum, Min, Max> arr{};
 
    for (std::size_t idx = 0; idx < result.ranges.size(); ++idx) {
      arr[idx] = result.strings.view().substr(result.ranges[idx].first,
                                              result.ranges[idx].second);
    }
 
#if MGUTILITY_CPLUSPLUS >= 201402L
    constexpr auto map = mgutility::custom_enum<Enum>::map;
    for (const auto &pair : map) {
#else
    for (const auto &pair : mgutility::custom_enum<Enum>::map) {
#endif
      if (pair.first >= static_cast<Enum>(Min) &&
          pair.first < static_cast<Enum>(Max)) {
        arr[static_cast<std::size_t>(pair.first) - Min] = pair.second;
      }
    }
 
    return arr;
  }
};
 
template <typename Enum, int Min = mgutility::enum_range<Enum>::min,
          int Max = mgutility::enum_range<Enum>::max>
MGUTILITY_CNSTXPR auto get_enum_array() noexcept
    -> enum_name_array<Enum, Min, Max> {
#if MGUTILITY_CPLUSPLUS > 201402L
  constexpr auto &cache = enum_array_cache<Enum, Min, Max>::parse_result;
  return enum_array_cache<Enum, Min, Max>::apply_custom(cache);
#else
  return enum_array_cache<Enum, Min, Max>::apply_custom(
      enum_array_cache<Enum, Min, Max>::value());
#endif
}
 
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{detail::find(arr, str)};
  return index == 0 ? mgutility::nullopt
                    : mgutility::optional<Enum>{static_cast<Enum>(index + Min)};
}
 
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 enumValue) noexcept
    -> mgutility::string_view {
  MGUTILITY_CNSTXPR_CLANG_WA auto arr = get_enum_array<Enum, Min, Max>();
  const auto index{(Min < 0 ? -Min : Min) + static_cast<int>(enumValue)};
  if (index < Min || index > static_cast<int>(arr.size()) - 1) {
    return mgutility::string_view{};
  }
 
  return arr[static_cast<size_t>(index)];
}
 
// NOLINTNEXTLINE [modernize-use-constraints]
template <typename Enum, int Min, int Max,
          detail::enable_if_t<detail::has_bit_or<Enum>::value, bool> = true>
MGUTILITY_CNSTXPR_CLANG_WA auto enum_name_impl(Enum enumValue) noexcept
    -> mgutility::fixed_string<enum_name_buffer<Enum>::size> {
 
  // 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>(enumValue);
 
  mgutility::fixed_string<enum_name_buffer<Enum>::size> bitmasked_name;
 
  if (index >= 0 && index < static_cast<int>(arr.size())) {
    bitmasked_name.append(arr[static_cast<size_t>(index)]);
  }
 
  if (!bitmasked_name.empty()) {
    return bitmasked_name;
  }
 
  for (auto i = 0; i < Max - Min; ++i) {
    if (i >= 0 && i < static_cast<int>(arr.size()) && arr[i].size() > 0 &&
        (enumValue & static_cast<Enum>(i)) == static_cast<Enum>(i)) {
      bitmasked_name.append(arr[i]).append("|");
    }
  }
 
  // Remove the trailing '|' if present
  if (!bitmasked_name.empty()) {
    bitmasked_name.pop_back();
  }
 
  return bitmasked_name;
}
} // namespace detail
} // namespace mgutility
 
#endif // MGUTILITY_REFLECTION_DETAIL_ENUM_NAME_IMPL_HPP