ClickHouse/src/Core/MultiEnum.h

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#pragma once
#include <cstdint>
#include <type_traits>
// Wrapper around enum that can have multiple values (or none) set at once.
template <typename EnumTypeT, typename StorageTypeT = std::uint64_t>
struct MultiEnum
{
using StorageType = StorageTypeT;
using EnumType = EnumTypeT;
MultiEnum() = default;
template <typename ... EnumValues, typename = std::enable_if_t<std::conjunction_v<std::is_same<EnumTypeT, EnumValues>...>>>
explicit MultiEnum(EnumValues ... v)
: MultiEnum((toBitFlag(v) | ... | 0u))
{}
template <typename ValueType, typename = std::enable_if_t<std::is_convertible_v<ValueType, StorageType>>>
explicit MultiEnum(ValueType v)
: bitset(v)
{
static_assert(std::is_unsigned_v<ValueType>);
static_assert(std::is_unsigned_v<StorageType> && std::is_integral_v<StorageType>);
}
MultiEnum(const MultiEnum & other) = default;
MultiEnum & operator=(const MultiEnum & other) = default;
bool isSet(EnumType value) const
{
return bitset & toBitFlag(value);
}
void set(EnumType value)
{
bitset |= toBitFlag(value);
}
void unSet(EnumType value)
{
bitset &= ~(toBitFlag(value));
}
void reset()
{
bitset = 0;
}
StorageType getValue() const
{
return bitset;
}
template <typename ValueType, typename = std::enable_if_t<std::is_convertible_v<ValueType, StorageType>>>
void setValue(ValueType new_value)
{
// Can't set value from any enum avoid confusion
static_assert(!std::is_enum_v<ValueType>);
bitset = new_value;
}
bool operator==(const MultiEnum & other) const
{
return bitset == other.bitset;
}
template <typename ValueType, typename = std::enable_if_t<std::is_convertible_v<ValueType, StorageType>>>
bool operator==(ValueType other) const
{
// Shouldn't be comparable with any enum to avoid confusion
static_assert(!std::is_enum_v<ValueType>);
return bitset == other;
}
template <typename U>
bool operator!=(U && other) const
{
return !(*this == other);
}
template <typename ValueType, typename = std::enable_if_t<std::is_convertible_v<ValueType, StorageType>>>
friend bool operator==(ValueType left, MultiEnum right)
{
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return right.operator==(left);
}
template <typename L, typename = typename std::enable_if<!std::is_same_v<L, MultiEnum>>::type>
friend bool operator!=(L left, MultiEnum right)
{
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return !(right.operator==(left));
}
private:
StorageType bitset = 0;
static StorageType toBitFlag(EnumType v) { return StorageType{1} << static_cast<StorageType>(v); }
};