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chatterino2/src/util/QMagicEnum.hpp
2024-03-23 11:22:42 +00:00

314 lines
9.4 KiB
C++

#pragma once
#include <magic_enum/magic_enum.hpp>
#include <QString>
#include <QStringView>
namespace chatterino::qmagicenum::detail {
template <bool, typename R>
struct EnableIfEnum {
};
template <typename R>
struct EnableIfEnum<true, R> {
using type = R;
};
template <typename T, typename R, typename BinaryPredicate = std::equal_to<>,
typename D = std::decay_t<T>>
using enable_if_t = typename EnableIfEnum<
std::is_enum_v<D> &&
std::is_invocable_r_v<bool, BinaryPredicate, QChar, QChar>,
R>::type;
template <std::size_t N>
consteval QStringView fromArray(const std::array<char16_t, N> &arr)
{
return QStringView{arr.data(), static_cast<QStringView::size_type>(N - 1)};
}
// Only the latin1 subset may be used right now, since it's easily convertible
template <std::size_t N>
consteval bool isLatin1(std::string_view maybe)
{
for (std::size_t i = 0; i < N; i++)
{
if (maybe[i] < 0x20 || maybe[i] > 0x7e)
{
return false;
}
}
return true;
}
template <typename BinaryPredicate>
inline constexpr bool eq(
QStringView a, QStringView b,
[[maybe_unused]] BinaryPredicate &&
p) noexcept(magic_enum::detail::is_nothrow_invocable<BinaryPredicate>())
{
// Note: operator== isn't constexpr
if (a.size() != b.size())
{
return false;
}
for (QStringView::size_type i = 0; i < a.size(); i++)
{
if (!p(a[i], b[i]))
{
return false;
}
}
return true;
}
template <typename C, typename E, E V>
consteval auto enumNameStorage()
{
constexpr auto utf8 = magic_enum::enum_name<V>();
static_assert(isLatin1<utf8.size()>(utf8),
"Can't convert non-latin1 UTF8 to UTF16");
std::array<C, utf8.size() + 1> storage;
for (std::size_t i = 0; i < utf8.size(); i++)
{
storage[i] = static_cast<C>(utf8[i]);
}
storage[utf8.size()] = 0;
return storage;
}
template <typename E, E V>
inline constexpr auto ENUM_NAME_STORAGE = enumNameStorage<char16_t, E, V>();
template <typename E, magic_enum::detail::enum_subtype S, std::size_t... I>
consteval auto namesStorage(std::index_sequence<I...> /*unused*/)
{
return std::array<QStringView, sizeof...(I)>{{detail::fromArray(
ENUM_NAME_STORAGE<E, magic_enum::enum_values<E, S>()[I]>)...}};
}
template <typename E,
magic_enum::detail::enum_subtype S = magic_enum::detail::subtype_v<E>>
inline constexpr auto NAMES_STORAGE = namesStorage<E, S>(
std::make_index_sequence<magic_enum::enum_count<E, S>()>{});
template <typename E, magic_enum::detail::enum_subtype S,
typename D = std::decay_t<E>>
using NamesStorage = decltype((NAMES_STORAGE<D, S>));
template <typename Op = std::equal_to<>>
class CaseInsensitive
{
static constexpr QChar toLower(QChar c) noexcept
{
return (c >= u'A' && c <= u'Z')
? QChar(c.unicode() + static_cast<char16_t>(u'a' - u'A'))
: c;
}
public:
template <typename L, typename R>
constexpr std::enable_if_t<std::is_same_v<std::decay_t<L>, QChar> &&
std::is_same_v<std::decay_t<R>, QChar>,
bool>
operator()(L lhs, R rhs) const noexcept
{
return Op{}(toLower(lhs), toLower(rhs));
}
};
} // namespace chatterino::qmagicenum::detail
namespace chatterino::qmagicenum {
/// @brief Get the name of an enum value
///
/// This version is much lighter on the compile times and is not restricted to the enum_range limitation.
///
/// @tparam V The enum value
/// @returns The name as a string view
template <auto V>
[[nodiscard]] consteval detail::enable_if_t<decltype(V), QStringView>
enumName() noexcept
{
return QStringView{
detail::fromArray(detail::ENUM_NAME_STORAGE<decltype(V), V>)};
}
/// @brief Get the name of an enum value
///
/// @param value The enum value
/// @returns The name as a string view. If @a value does not have name or the
/// value is out of range an empty string is returned.
template <typename E,
magic_enum::detail::enum_subtype S = magic_enum::detail::subtype_v<E>>
[[nodiscard]] constexpr detail::enable_if_t<E, QStringView> enumName(
E value) noexcept
{
using D = std::decay_t<E>;
if (const auto i = magic_enum::enum_index<D, S>(value))
{
return detail::NAMES_STORAGE<D, S>[*i];
}
return {};
}
/// @brief Gets a static QString from @a view.
///
/// @pre @a view must be a static string view (i.e. it must be valid throughout
/// the entire duration of the program).
///
/// @param view The view to turn into a static string
/// @returns Qt6: A static string (never gets freed), Qt5: regular string
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
[[nodiscard]] inline QString staticString(QStringView view) noexcept
{
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
return QString(QStringPrivate(nullptr, const_cast<char16_t *>(view.utf16()),
view.size()));
}
#else
[[nodiscard]] inline QString staticString(QStringView view)
{
return view.toString();
}
#endif
/// @brief Get the name of an enum value
///
/// This version is much lighter on the compile times and is not restricted to
/// the enum_range limitation.
///
/// @tparam V The enum value
/// @returns The name as a string. The returned string is static.
template <auto V>
[[nodiscard]] inline detail::enable_if_t<decltype(V), QString>
enumNameString() noexcept
{
return staticString(enumName<V>());
}
/// @brief Get the name of an enum value
///
/// This version is much lighter on the compile times and is not restricted to
/// the enum_range limitation.
///
/// @tparam V The enum value
/// @returns The name as a string. If @a value does not have name or the
/// value is out of range an empty string is returned.
/// The returned string is static.
template <typename E,
magic_enum::detail::enum_subtype S = magic_enum::detail::subtype_v<E>>
[[nodiscard]] inline detail::enable_if_t<E, QString> enumNameString(
E value) noexcept
{
using D = std::decay_t<E>;
return staticString(enumName<D, S>(value));
}
/// @brief Gets the enum value from a name
///
/// @tparam E The enum type to parse the @a name as
/// @param name The name of the enum value to parse
/// @param p A predicate to compare characters of a string
/// (defaults to std::equal_to)
/// @returns A `std::optional` of the parsed value. If no value was parsed,
/// `std::nullopt` is returned.
template <typename E,
magic_enum::detail::enum_subtype S = magic_enum::detail::subtype_v<E>,
typename BinaryPredicate = std::equal_to<>>
[[nodiscard]] constexpr detail::enable_if_t<E, std::optional<std::decay_t<E>>,
BinaryPredicate>
enumCast(QStringView name,
[[maybe_unused]] BinaryPredicate p =
{}) noexcept(magic_enum::detail::
is_nothrow_invocable<BinaryPredicate>())
{
using D = std::decay_t<E>;
if constexpr (magic_enum::enum_count<D, S>() == 0)
{
static_cast<void>(name);
return std::nullopt; // Empty enum.
}
for (std::size_t i = 0; i < magic_enum::enum_count<D, S>(); i++)
{
if (detail::eq(name, detail::NAMES_STORAGE<D, S>[i], p))
{
return magic_enum::enum_value<D, S>(i);
}
}
return std::nullopt; // Invalid value or out of range.
}
/// @brief Constructs a name from the @a flags
///
/// @param flags The combined flags to construct the name from
/// @param sep A separator between each flag (defaults to u'|')
/// @returns A string containing all names separated by @a sep. If any flag in
/// @a flags is out of rage or does not have a name, an empty string
/// is returned.
template <typename E>
[[nodiscard]] inline detail::enable_if_t<E, QString> enumFlagsName(
E flags, char16_t sep = u'|')
{
using D = std::decay_t<E>;
using U = std::underlying_type_t<D>;
constexpr auto S = magic_enum::detail::enum_subtype::flags; // NOLINT
QString name;
auto checkValue = U{0};
for (std::size_t i = 0; i < magic_enum::enum_count<D, S>(); ++i)
{
const auto v = static_cast<U>(magic_enum::enum_value<D, S>(i));
if ((static_cast<U>(flags) & v) != 0)
{
const auto n = detail::NAMES_STORAGE<D, S>[i];
if (!n.empty())
{
checkValue |= v;
if (!name.isEmpty())
{
name.append(sep);
}
name.append(n);
}
else
{
return {}; // Value out of range.
}
}
}
if (checkValue != 0 && checkValue == static_cast<U>(flags))
{
return name;
}
return {}; // Invalid value or out of range.
}
/// @brief Get the names of all values from @a E.
///
/// @tparam E The enum type
/// @returns A `std::array` of all names (`QStringView`s)
template <typename E,
magic_enum::detail::enum_subtype S = magic_enum::detail::subtype_v<E>>
[[nodiscard]] constexpr auto enumNames() noexcept
-> detail::enable_if_t<E, detail::NamesStorage<E, S>>
{
return detail::NAMES_STORAGE<std::decay_t<E>, S>;
}
/// Allows you to write qmagicenum::enumCast<foo>("bar", qmagicenum::CASE_INSENSITIVE)
inline constexpr auto CASE_INSENSITIVE = detail::CaseInsensitive<>{};
} // namespace chatterino::qmagicenum