Trait sp_runtime::PerThing

source · [−]
pub trait PerThing: Saturating + Copy + Default + Eq + PartialEq<Self> + Ord + PartialOrd<Self> + Bounded + Debug {
    type Inner: BaseArithmetic + Unsigned + Copy + Into<u128> + Debug;
    type Upper: BaseArithmetic + Copy + From<Self::Inner> + TryInto<Self::Inner> + UniqueSaturatedInto<Self::Inner> + Unsigned + Debug;

    const ACCURACY: Self::Inner;

Show 15 methods
    fn deconstruct(self) -> Self::Inner;

    fn from_parts(parts: Self::Inner) -> Self;

    fn from_fraction(x: f64) -> Self;

    fn from_rational_approximation<N>(p: N, q: N) -> Self
    where
        N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper> + Div<N, Output = N> + Rem<N, Output = N> + Add<N, Output = N> + Unsigned,
        Self::Inner: Into<N>;

    fn zero() -> Self { ... }

    fn is_zero(&self) -> bool { ... }

    fn one() -> Self { ... }

    fn is_one(&self) -> bool { ... }

    fn from_percent(x: Self::Inner) -> Self { ... }

    fn square(self) -> Self { ... }

    fn mul_floor<N>(self, b: N) -> N
    where
        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Unsigned,
        Self::Inner: Into<N>,
    { ... }

    fn mul_ceil<N>(self, b: N) -> N
    where
        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Unsigned,
        Self::Inner: Into<N>,
    { ... }

    fn saturating_reciprocal_mul<N>(self, b: N) -> N
    where
        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,
        Self::Inner: Into<N>,
    { ... }

    fn saturating_reciprocal_mul_floor<N>(self, b: N) -> N
    where
        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,
        Self::Inner: Into<N>,
    { ... }

    fn saturating_reciprocal_mul_ceil<N>(self, b: N) -> N
    where
        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,
        Self::Inner: Into<N>,
    { ... }

}
Expand description

Re-export top-level arithmetic stuff. Something that implements a fixed point ration with an arbitrary granularity X, as parts per X.

Associated Types

The data type used to build this per-thingy.

A data type larger than Self::Inner, used to avoid overflow in some computations. It must be able to compute ACCURACY^2.

Associated Constants

The accuracy of this type.

Required methods

Consume self and return the number of parts per thing.

Build this type from a number of parts per thing.

Converts a fraction into Self.

Approximate the fraction p/q into a per-thing fraction. This will never overflow.

The computation of this approximation is performed in the generic type N. Given M as the data type that can hold the maximum value of this per-thing (e.g. u32 for perbill), this can only work if N == M or N: From<M> + TryInto<M>.

Note that this always rounds down, i.e.

// 989/100 is technically closer to 99%.
assert_eq!(
		Percent::from_rational_approximation(989u64, 1000),
		Percent::from_parts(98),
	);

Provided methods

Equivalent to Self::from_parts(0).

Return true if this is nothing.

Equivalent to Self::from_parts(Self::ACCURACY).

Return true if this is one.

Build this type from a percent. Equivalent to Self::from_parts(x * Self::ACCURACY / 100) but more accurate and can cope with potential type overflows.

Return the product of multiplication of this value by itself.

Multiplication that always rounds down to a whole number. The standard Mul rounds to the nearest whole number.

// round to nearest
assert_eq!(Percent::from_percent(34) * 10u64, 3);
assert_eq!(Percent::from_percent(36) * 10u64, 4);

// round down
assert_eq!(Percent::from_percent(34).mul_floor(10u64), 3);
assert_eq!(Percent::from_percent(36).mul_floor(10u64), 3);

Multiplication that always rounds the result up to a whole number. The standard Mul rounds to the nearest whole number.

// round to nearest
assert_eq!(Percent::from_percent(34) * 10u64, 3);
assert_eq!(Percent::from_percent(36) * 10u64, 4);

// round up
assert_eq!(Percent::from_percent(34).mul_ceil(10u64), 4);
assert_eq!(Percent::from_percent(36).mul_ceil(10u64), 4);

Saturating multiplication by the reciprocal of self. The result is rounded to the nearest whole number and saturates at the numeric bounds instead of overflowing.

assert_eq!(Percent::from_percent(50).saturating_reciprocal_mul(10u64), 20);

Saturating multiplication by the reciprocal of self. The result is rounded down to the nearest whole number and saturates at the numeric bounds instead of overflowing.

// round to nearest
assert_eq!(Percent::from_percent(60).saturating_reciprocal_mul(10u64), 17);
// round down
assert_eq!(Percent::from_percent(60).saturating_reciprocal_mul_floor(10u64), 16);

Saturating multiplication by the reciprocal of self. The result is rounded up to the nearest whole number and saturates at the numeric bounds instead of overflowing.

// round to nearest
assert_eq!(Percent::from_percent(61).saturating_reciprocal_mul(10u64), 16);
// round up
assert_eq!(Percent::from_percent(61).saturating_reciprocal_mul_ceil(10u64), 17);

Implementors