Class allowing a value object (integer, string, etc) to be optional, by storing a current value, default value and a boolean to state which is valid.

The template type 'Type' must be default-constructible.

public: const Type & Default() const

Returns the default value.

public: bool IsDefaultDefined() const

Returns true if the default value has been set.

public: bool IsDefined() const

Returns true if the value has been set.

public: bool Load
(
    Geo::IGeoStream & stream
)

Load this Geo::Optional<Type> from a Geo::IGeoStream.

Expected the file value to be in little-endian, and restores to native. Does not read/modify the default value.

public: bool operator!=
(
    const Optional & v
) const

Inequality operator.

public: Optional & operator=
(
    const Type & v
)

Assignment operator.

public: bool operator==
(
    const Optional & v
) const

Equality operator.

public: Optional()

Constructor. Defaults to undefined.

public: Optional
(
    const Type & v
)

Explicit construction from a value.

public: Optional
(
    const Optional & v
)

Copy constructor.

public: Optional
(
    void * ,
    const Type & def
)

Constructor that allows you to set a default, but leave value undefined.

public: bool Save
(
    Geo::IGeoStream & stream
) const

Save this Geo::Optional<Type> to a Geo::IGeoStream.

Writes the file value in little-endian. Does not store the default value.

public: void SetDefault
(
    const Type & val
)

Set the default value.

public: void Undefine()

Unsets the value, returning it to the default.

public: void UndefineDefault()

Unsets the default value.

public: const Type & Value() const

Return the value, if set, otherwise the default.