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	explicit (false) Flags(enum_type e) noexcept
	Construct from a single enum flag.
constexpr	Flags (value_type val) noexcept
	Construct from an underlying value.

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,
};
DFX_DECLARE_FLAGS(Modes, Mode);
DFX_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() [1/2]

template<IsEnum Enum>

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

constexprdefaultnoexcept

Construct an empty flag set (value = 0).

Flags() [2/2]

template<IsEnum Enum>

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

inlineexplicitconstexprnoexcept

Construct from an underlying value.

This constructor allows creating a flag set directly from an integral value. It is primarily intended for cases where flags have been serialized or manipulated as integers and need to be re-wrapped.

Warning

This constructor is unsafe as it performs no validation. It is the caller's responsibility to ensure that val represents a valid combination of flags for the enum_type. Passing arbitrary integers that do not map to valid bitmasks may result in undefined logical behavior during later flag testing.

Parameters

val	The raw integral value to be interpreted as a bitmask.

Member Function Documentation

explicit()

template<IsEnum Enum>

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

inlineconstexprnoexcept

Construct from a single enum flag.

Parameters

e	Flag to set.

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

• lib/dfx-utilities/Flags.hpp