dfx::Utils::Flags< Enum > Class Template Reference

Typesafe bitmask wrapper for enum flags. More...

#include <dfx-utilities/Flags.hpp>

Public Types
using	enum_type = Enum
	The wrapped enum type.
using	value_type = std::underlying_type_t<Enum>
	The underlying integer storage type.

Public Member Functions
constexpr	Flags () noexcept=default
	Construct an empty flag set (value = 0).
constexpr	Flags (enum_type e) noexcept
	Construct from a single enum flag.
constexpr	Flags (std::initializer_list< enum_type > f) noexcept
	Construct from an initializer-list of flags. All provided flags are OR-ed into the resulting mask.
constexpr Flags< enum_type > &	setFlag (enum_type flag, bool on=true) noexcept
	Set or clear a single flag.
constexpr bool	testFlag (enum_type flag) const noexcept
	Test whether a given flag is set.
constexpr bool	testAnyFlag (Flags< enum_type > const &flags) const noexcept
	Test whether any bit from flags is set.
constexpr bool	testAllFlags (Flags< enum_type > const &flags) const noexcept
	Test whether all bits from flags are set.
constexpr bool	operator== (Flags< enum_type > const &other) const noexcept
	Equality comparison between two flag sets.
constexpr bool	operator!= (Flags< enum_type > const &other) const noexcept
	Inequality comparison between two flag sets.
constexpr bool	operator== (enum_type flag) const noexcept
	Compare the flag set against a single enum mask.
constexpr bool	operator!= (enum_type flag) const noexcept
	Negated form of operator==(enum_type).
constexpr	operator enum_type () const noexcept
	Implicit conversion to the enum type.
constexpr	operator value_type () const noexcept
	Implicit conversion to the underlying integer storage type.
constexpr Flags< enum_type >	operator& (enum_type mask) const noexcept
	Bitwise AND with an enum mask.
constexpr Flags< enum_type >	operator& (Flags< enum_type > mask) const noexcept
	Bitwise AND with another flag set.
constexpr Flags< enum_type > &	operator&= (enum_type mask) noexcept
	In-place bitwise AND with an enum mask.
constexpr Flags< enum_type > &	operator&= (Flags< enum_type > mask) noexcept
	In-place bitwise AND with another flag set.
constexpr Flags< enum_type >	operator| (enum_type mask) const noexcept
	Bitwise OR with an enum mask.
constexpr Flags< enum_type >	operator| (Flags< enum_type > mask) const noexcept
	Bitwise OR with another flag set.
constexpr Flags< enum_type > &	operator|= (enum_type mask) noexcept
	In-place bitwise OR with an enum mask.
constexpr Flags< enum_type > &	operator|= (Flags< enum_type > mask) noexcept
	In-place bitwise OR with another flag set.
constexpr Flags< enum_type >	operator^ (enum_type mask) const noexcept
	Bitwise XOR with an enum mask.
constexpr Flags< enum_type >	operator^ (Flags< enum_type > mask) const noexcept
	Bitwise XOR with another flag set.
constexpr Flags< enum_type > &	operator^= (enum_type mask) noexcept
	In-place bitwise XOR with an enum mask.
constexpr Flags< enum_type > &	operator^= (Flags< enum_type > mask) noexcept
	In-place bitwise XOR with another flag set.
constexpr Flags< enum_type >	operator~ () const noexcept
	Bitwise NOT.
constexpr bool	operator! () const noexcept
	Logical negation.

Detailed Description

template<IsEnum Enum>
class dfx::Utils::Flags< Enum >

Typesafe bitmask wrapper for enum flags.

Flags<Enum> wraps an enum whose enumerators represent bit flags (typically powers of two), and provides common bitmask operations (|, &, ^, ~), as well as helpers to set/test flags.

The internal storage is the enum underlying type (std::underlying_type_t<Enum>).

Template Parameters

Enum	An enum type used as a bitmask (must satisfy IsEnum).

Typical usage

enum class Mode : uint32_t
{
    Read  = 0x01,
    Write = 0x02,
    Exec  = 0x04,
};
DECLARE_FLAGS(Modes, Mode);
DECLARE_OPERATOR_FOR_FLAGS(Modes);
 
Modes m{ Mode::Read };
m.setFlag(Mode::Write);
if (m.testAllFlags(Mode::Read  | Mode::Write)) { ... }

Notes / caveats

• No validation is performed: if your enum values are not proper bit flags, semantics are on you.
• operator enum_type() converts the underlying bitmask back to the enum type; this may produce a value that is not one of the declared enumerators. This is intentional for flag enums.

Member Typedef Documentation

enum_type

template<IsEnum Enum>

using dfx::Utils::Flags< Enum >::enum_type = Enum

The wrapped enum type.

value_type

template<IsEnum Enum>

using dfx::Utils::Flags< Enum >::value_type = std::underlying_type_t<Enum>

The underlying integer storage type.

Constructor & Destructor Documentation

Flags() [1/3]

template<IsEnum Enum>

dfx::Utils::Flags< Enum >::Flags ( )

constexprdefaultnoexcept

Construct an empty flag set (value = 0).

Flags() [2/3]

template<IsEnum Enum>

dfx::Utils::Flags< Enum >::Flags ( enum_type e )

inlineconstexprnoexcept

Construct from a single enum flag.

Parameters

e	Flag to set.

Flags() [3/3]

template<IsEnum Enum>

dfx::Utils::Flags< Enum >::Flags ( std::initializer_list< enum_type > f )

inlineconstexprnoexcept

Construct from an initializer-list of flags. All provided flags are OR-ed into the resulting mask.

Parameters

f	List of flags to set.

Member Function Documentation

operator enum_type()

template<IsEnum Enum>

dfx::Utils::Flags< Enum >::operator enum_type ( ) const

inlinenodiscardconstexprnoexcept

Implicit conversion to the enum type.

Returns

The current bitmask reinterpreted as the enum type.

Warning

The returned enum value may not correspond to a named enumerator.

operator value_type()

template<IsEnum Enum>

dfx::Utils::Flags< Enum >::operator value_type ( ) const

inlinenodiscardconstexprnoexcept

Implicit conversion to the underlying integer storage type.

Returns

The underlying bitmask value.

operator!()

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::operator! ( ) const

inlinenodiscardconstexprnoexcept

Logical negation.

operator!=() [1/2]

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::operator!= ( enum_type flag ) const

inlinenodiscardconstexprnoexcept

Negated form of operator==(enum_type).

operator!=() [2/2]

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::operator!= ( Flags< enum_type > const & other ) const

inlinenodiscardconstexprnoexcept

Inequality comparison between two flag sets.

operator&() [1/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator& ( enum_type mask ) const

inlinenodiscardconstexprnoexcept

Bitwise AND with an enum mask.

operator&() [2/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator& ( Flags< enum_type > mask ) const

inlinenodiscardconstexprnoexcept

Bitwise AND with another flag set.

operator&=() [1/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator&= ( enum_type mask )

inlineconstexprnoexcept

In-place bitwise AND with an enum mask.

operator&=() [2/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator&= ( Flags< enum_type > mask )

inlineconstexprnoexcept

In-place bitwise AND with another flag set.

operator==() [1/2]

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::operator== ( enum_type flag ) const

inlinenodiscardconstexprnoexcept

Compare the flag set against a single enum mask.

operator==() [2/2]

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::operator== ( Flags< enum_type > const & other ) const

inlinenodiscardconstexprnoexcept

Equality comparison between two flag sets.

operator^() [1/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator^ ( enum_type mask ) const

inlinenodiscardconstexprnoexcept

Bitwise XOR with an enum mask.

operator^() [2/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator^ ( Flags< enum_type > mask ) const

inlinenodiscardconstexprnoexcept

Bitwise XOR with another flag set.

operator^=() [1/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator^= ( enum_type mask )

inlineconstexprnoexcept

In-place bitwise XOR with an enum mask.

operator^=() [2/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator^= ( Flags< enum_type > mask )

inlineconstexprnoexcept

In-place bitwise XOR with another flag set.

operator|() [1/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator| ( enum_type mask ) const

inlinenodiscardconstexprnoexcept

Bitwise OR with an enum mask.

operator|() [2/2]

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator| ( Flags< enum_type > mask ) const

inlinenodiscardconstexprnoexcept

Bitwise OR with another flag set.

operator|=() [1/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator|= ( enum_type mask )

inlineconstexprnoexcept

In-place bitwise OR with an enum mask.

operator|=() [2/2]

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::operator|= ( Flags< enum_type > mask )

inlineconstexprnoexcept

In-place bitwise OR with another flag set.

operator~()

template<IsEnum Enum>

Flags< enum_type > dfx::Utils::Flags< Enum >::operator~ ( ) const

inlinenodiscardconstexprnoexcept

Bitwise NOT.

setFlag()

template<IsEnum Enum>

Flags< enum_type > & dfx::Utils::Flags< Enum >::setFlag ( enum_type flag, bool on = true )

inlineconstexprnoexcept

Set or clear a single flag.

Parameters

flag	Flag to modify.
on	If true, sets the flag; if false, clears it.

Returns

*this.

testAllFlags()

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::testAllFlags ( Flags< enum_type > const & flags ) const

inlinenodiscardconstexprnoexcept

Test whether all bits from flags are set.

Parameters

flags

Mask of bits to test.

Returns

True if all those bits are set.

testAnyFlag()

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::testAnyFlag ( Flags< enum_type > const & flags ) const

inlinenodiscardconstexprnoexcept

Test whether any bit from flags is set.

Parameters

flags

Mask of bits to test.

Returns

True if at least one of those bits is set.

testFlag()

template<IsEnum Enum>

bool dfx::Utils::Flags< Enum >::testFlag ( enum_type flag ) const

inlinenodiscardconstexprnoexcept

Test whether a given flag is set.

This checks that all bits in flag are present in this mask.

Parameters

flag	Flag (or bitmask) to test.

Returns

True if all bits from flag are set.

---

The documentation for this class was generated from the following file:

• lib/dfx-utilities/Flags.hpp