Enum UnitKind 

pub enum UnitKind {
    Si {
        unit_type: Arc<str>,
        name: Arc<str>,
        prefix: Option<Arc<str>>,
        prefix_exponent: Option<i32>,
    },
    Conversion {
        unit_type: Arc<str>,
        name: Option<Arc<str>>,
        factor: Option<f64>,
        factor_unit: Option<EntityId>,
        offset: Option<f64>,
    },
    Derived {
        unit_type: Arc<str>,
        elements: Vec<(EntityId, i64)>,
    },
    Monetary {
        currency: Option<Arc<str>>,
    },
    ContextDependent {
        unit_type: Arc<str>,
    },
}

A unit as the file states it.

Variants

Si

IfcSIUnit: a base SI unit with an optional decimal prefix.

Fields

unit_type: Arc<str>

IfcUnitEnum, e.g. LENGTHUNIT.

name: Arc<str>

IfcSIUnitName, e.g. METRE.

prefix: Option<Arc<str>>

IfcSIPrefix, e.g. MILLI. None means unprefixed.

prefix_exponent: Option<i32>

Decimal exponent of the prefix: MILLI is Some(-3), absent is Some(0), and a prefix that is not an IfcSIPrefix is None.

Exposed as an exponent rather than a factor so callers can apply it exactly instead of multiplying by a rounded 0.001. An unknown prefix is not read as “unprefixed”: that would silently rescale every value in the unit.

Conversion

IfcConversionBasedUnit: a named unit defined by a factor.

Fields

unit_type: Arc<str>

IfcUnitEnum.

name: Option<Arc<str>>

The unit’s name, e.g. inch.

factor: Option<f64>

The numeric conversion factor, when readable.

factor_unit: Option<EntityId>

The unit the factor is expressed in.

offset: Option<f64>

IfcConversionBasedUnitWithOffset.ConversionOffset, as stated.

None for a plain conversion-based unit. Kept raw: IFC4’s own documentation contradicts itself on which direction the offset applies, so this crate does not apply it.

Derived

IfcDerivedUnit: a product of powers of other units.

Fields

unit_type: Arc<str>

IfcDerivedUnitEnum, e.g. VOLUMETRICFLOWRATEUNIT.

elements: Vec<(EntityId, i64)>

The (unit, exponent) elements.

Monetary

IfcMonetaryUnit: a currency, with no dimension.

Fields

currency: Option<Arc<str>>

ISO currency code as stated.

ContextDependent

IfcContextDependentUnit or another named unit form.

Fields

unit_type: Arc<str>

IfcUnitEnum.

Implementations

impl UnitKind

pub fn unit_type(&self) -> Option<&str>

The IfcUnitEnum this unit declares, when it has one.

IfcMonetaryUnit has none: it is not an IfcNamedUnit.

pub fn si_scale(&self) -> Option<f64>

Multiplier converting a value in this unit to the unprefixed SI unit.

The prefix is raised to the unit’s power: MILLI SQUARE_METRE gives 1e-6 and MILLI CUBIC_METRE 1e-9. None for an unknown prefix.

Only defined for Si: a conversion-based unit needs its factor unit resolved too, and a derived unit needs its elements combined, so neither can answer honestly on its own. crate::exact_unit resolves all three to the SI base unit.

Trait Implementations

impl Clone for UnitKind

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UnitKind

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for UnitKind

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for UnitKind