Trait sp_arithmetic::per_things::PerThing

pub trait PerThing: Sized + Saturating + Copy + Default + Eq + PartialEq + Ord + PartialOrd + 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;

    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>,
    { ... }
}

Something that implements a fixed point ration with an arbitrary granularity X, as parts per X.

Associated Types

type Inner: BaseArithmetic + Unsigned + Copy + Into<u128> + Debug

The data type used to build this per-thingy.

type Upper: BaseArithmetic + Copy + From<Self::Inner> + TryInto<Self::Inner> + UniqueSaturatedInto<Self::Inner> + Unsigned + Debug

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

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Associated Constants

const ACCURACY: Self::Inner

The accuracy of this type.

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Required methods

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

Converts a fraction into 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>, 

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),
	);

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Provided methods

fn zero() -> Self

Equivalent to Self::from_parts(0).

fn is_zero(&self) -> bool

Return true if this is nothing.

fn one() -> Self

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

fn is_one(&self) -> bool

Return true if this is one.

fn from_percent(x: Self::Inner) -> Self

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.

fn square(self) -> Self

Return the product of multiplication of this value by itself.

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>, 

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);

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>, 

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);

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>, 

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);

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>, 

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);

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>, 

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);

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Implementors

impl PerThing for PerU16

type Inner = u16

type Upper = u32

const ACCURACY: Self::Inner

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

NOTE: saturate to 0 or 1 if x is beyond [0, 1]

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 + Zero + One,
    Self::Inner: Into<N>, 

impl PerThing for Perbill

type Inner = u32

type Upper = u64

const ACCURACY: Self::Inner

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

NOTE: saturate to 0 or 1 if x is beyond [0, 1]

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 + Zero + One,
    Self::Inner: Into<N>, 

impl PerThing for Percent

type Inner = u8

type Upper = u16

const ACCURACY: Self::Inner

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

NOTE: saturate to 0 or 1 if x is beyond [0, 1]

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 + Zero + One,
    Self::Inner: Into<N>, 

impl PerThing for Permill

type Inner = u32

type Upper = u64

const ACCURACY: Self::Inner

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

NOTE: saturate to 0 or 1 if x is beyond [0, 1]

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 + Zero + One,
    Self::Inner: Into<N>, 

impl PerThing for Perquintill

type Inner = u64

type Upper = u128

const ACCURACY: Self::Inner

fn deconstruct(self) -> Self::Inner

Consume self and return the number of parts per thing.

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

Build this type from a number of parts per thing.

fn from_fraction(x: f64) -> Self

NOTE: saturate to 0 or 1 if x is beyond [0, 1]

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 + Zero + One,
    Self::Inner: Into<N>, 

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