Permanent identifier for entities, assets and any object that must keep the same identity across sessions. More...

#include <quasar/core/UUID.h>

Public Member Functions
constexpr	UUID ()=default
	Creates an invalid UUID, with the value 0.
constexpr	UUID (std::uint64_t value)
	Creates a UUID from a saved value, for example when a scene is loaded.
constexpr std::uint64_t	GetValue () const
	Returns the raw value, to save the UUID in a file.
constexpr bool	IsValid () const
	Returns true if the UUID is not the reserved value 0.
std::string	ToString () const
	Returns the UUID as text, to save it in a file: 16 lowercase hexadecimal digits.
constexpr auto	operator<=> (const UUID &) const =default
	Compares two UUIDs by their value, so they can be sorted and used as map keys.

Static Public Member Functions
static UUID	Generate ()
	Creates a new random UUID.
static std::optional< UUID >	FromString (std::string_view text)
	Reads a UUID from the text written by ToString().

Detailed Description

Permanent identifier for entities, assets and any object that must keep the same identity across sessions.

The value is saved as is in scene and asset files. The value 0 is reserved: a default-constructed UUID is invalid. Use Generate() to create a new identifier. A UUID can be used as a key in std::map and std::unordered_map.

Constructor & Destructor Documentation

◆ UUID()

Quasar::UUID::UUID ( std::uint64_t value )

inlineexplicitconstexpr

Creates a UUID from a saved value, for example when a scene is loaded.

Parameters

value The value returned by GetValue() when the UUID was saved.

Member Function Documentation

◆ Generate()

UUID Quasar::UUID::Generate ( )

static

Creates a new random UUID.

Safe to call from any thread.

Returns: A valid UUID, never equal to 0.

◆ GetValue()

std::uint64_t Quasar::UUID::GetValue ( ) const

inlineconstexpr

Returns the raw value, to save the UUID in a file.

Returns: The 64-bit value of the UUID.

◆ IsValid()

bool Quasar::UUID::IsValid ( ) const

inlineconstexpr

Returns true if the UUID is not the reserved value 0.

Returns: False for a default-constructed UUID, true for a generated one.

◆ ToString()

std::string Quasar::UUID::ToString ( ) const

Returns the UUID as text, to save it in a file: 16 lowercase hexadecimal digits.

Returns: For example "00ab3f9c12e45d07". An invalid UUID gives "0000000000000000".

◆ FromString()

std::optional< UUID > Quasar::UUID::FromString ( std::string_view text )

static

Reads a UUID from the text written by ToString().

Nothing is logged when the text is invalid: the caller knows which file or field it came from, so it can report a clearer error.