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Diffstat (limited to 'third_party/rust/euclid/src/length.rs')
-rw-r--r-- | third_party/rust/euclid/src/length.rs | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/third_party/rust/euclid/src/length.rs b/third_party/rust/euclid/src/length.rs new file mode 100644 index 0000000000..e65d38b61d --- /dev/null +++ b/third_party/rust/euclid/src/length.rs @@ -0,0 +1,609 @@ +// Copyright 2014 The Servo Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +//! A one-dimensional length, tagged with its units. + +use crate::approxeq::ApproxEq; +use crate::num::Zero; +use crate::scale::Scale; +use crate::approxord::{max, min}; + +use crate::num::One; +use core::cmp::Ordering; +use core::fmt; +use core::hash::{Hash, Hasher}; +use core::iter::Sum; +use core::marker::PhantomData; +use core::ops::{Add, Div, Mul, Neg, Sub}; +use core::ops::{AddAssign, DivAssign, MulAssign, SubAssign}; +use num_traits::{NumCast, Saturating}; +#[cfg(feature = "serde")] +use serde::{Deserialize, Deserializer, Serialize, Serializer}; +#[cfg(feature = "bytemuck")] +use bytemuck::{Zeroable, Pod}; + +/// A one-dimensional distance, with value represented by `T` and unit of measurement `Unit`. +/// +/// `T` can be any numeric type, for example a primitive type like `u64` or `f32`. +/// +/// `Unit` is not used in the representation of a `Length` value. It is used only at compile time +/// to ensure that a `Length` stored with one unit is converted explicitly before being used in an +/// expression that requires a different unit. It may be a type without values, such as an empty +/// enum. +/// +/// You can multiply a `Length` by a `scale::Scale` to convert it from one unit to +/// another. See the [`Scale`] docs for an example. +/// +/// [`Scale`]: struct.Scale.html +#[repr(C)] +pub struct Length<T, Unit>(pub T, #[doc(hidden)] pub PhantomData<Unit>); + +impl<T: Clone, U> Clone for Length<T, U> { + fn clone(&self) -> Self { + Length(self.0.clone(), PhantomData) + } +} + +impl<T: Copy, U> Copy for Length<T, U> {} + +#[cfg(feature = "serde")] +impl<'de, T, U> Deserialize<'de> for Length<T, U> +where + T: Deserialize<'de>, +{ + fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> + where + D: Deserializer<'de>, + { + Ok(Length(Deserialize::deserialize(deserializer)?, PhantomData)) + } +} + +#[cfg(feature = "serde")] +impl<T, U> Serialize for Length<T, U> +where + T: Serialize, +{ + fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> + where + S: Serializer, + { + self.0.serialize(serializer) + } +} + +#[cfg(feature = "bytemuck")] +unsafe impl<T: Zeroable, U> Zeroable for Length<T, U> {} + +#[cfg(feature = "bytemuck")] +unsafe impl<T: Pod, U: 'static> Pod for Length<T, U> {} + +impl<T, U> Length<T, U> { + /// Associate a value with a unit of measure. + #[inline] + pub const fn new(x: T) -> Self { + Length(x, PhantomData) + } +} + +impl<T: Clone, U> Length<T, U> { + /// Unpack the underlying value from the wrapper. + pub fn get(self) -> T { + self.0 + } + + /// Cast the unit + #[inline] + pub fn cast_unit<V>(self) -> Length<T, V> { + Length::new(self.0) + } + + /// Linearly interpolate between this length and another length. + /// + /// # Example + /// + /// ```rust + /// use euclid::default::Length; + /// + /// let from = Length::new(0.0); + /// let to = Length::new(8.0); + /// + /// assert_eq!(from.lerp(to, -1.0), Length::new(-8.0)); + /// assert_eq!(from.lerp(to, 0.0), Length::new( 0.0)); + /// assert_eq!(from.lerp(to, 0.5), Length::new( 4.0)); + /// assert_eq!(from.lerp(to, 1.0), Length::new( 8.0)); + /// assert_eq!(from.lerp(to, 2.0), Length::new(16.0)); + /// ``` + #[inline] + pub fn lerp(self, other: Self, t: T) -> Self + where + T: One + Sub<Output = T> + Mul<Output = T> + Add<Output = T>, + { + let one_t = T::one() - t.clone(); + Length::new(one_t * self.0.clone() + t * other.0) + } +} + +impl<T: PartialOrd, U> Length<T, U> { + /// Returns minimum between this length and another length. + #[inline] + pub fn min(self, other: Self) -> Self { + min(self, other) + } + + /// Returns maximum between this length and another length. + #[inline] + pub fn max(self, other: Self) -> Self { + max(self, other) + } +} + +impl<T: NumCast + Clone, U> Length<T, U> { + /// Cast from one numeric representation to another, preserving the units. + #[inline] + pub fn cast<NewT: NumCast>(self) -> Length<NewT, U> { + self.try_cast().unwrap() + } + + /// Fallible cast from one numeric representation to another, preserving the units. + pub fn try_cast<NewT: NumCast>(self) -> Option<Length<NewT, U>> { + NumCast::from(self.0).map(Length::new) + } +} + +impl<T: fmt::Debug, U> fmt::Debug for Length<T, U> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + self.0.fmt(f) + } +} + +impl<T: Default, U> Default for Length<T, U> { + #[inline] + fn default() -> Self { + Length::new(Default::default()) + } +} + +impl<T: Hash, U> Hash for Length<T, U> { + fn hash<H: Hasher>(&self, h: &mut H) { + self.0.hash(h); + } +} + +// length + length +impl<T: Add, U> Add for Length<T, U> { + type Output = Length<T::Output, U>; + + fn add(self, other: Self) -> Self::Output { + Length::new(self.0 + other.0) + } +} + +// length + &length +impl<T: Add + Copy, U> Add<&Self> for Length<T, U> { + type Output = Length<T::Output, U>; + + fn add(self, other: &Self) -> Self::Output { + Length::new(self.0 + other.0) + } +} + +// length_iter.copied().sum() +impl<T: Add<Output = T> + Zero, U> Sum for Length<T, U> { + fn sum<I: Iterator<Item=Self>>(iter: I) -> Self { + iter.fold(Self::zero(), Add::add) + } +} + +// length_iter.sum() +impl<'a, T: 'a + Add<Output = T> + Copy + Zero, U: 'a> Sum<&'a Self> for Length<T, U> { + fn sum<I: Iterator<Item=&'a Self>>(iter: I) -> Self { + iter.fold(Self::zero(), Add::add) + } +} + +// length += length +impl<T: AddAssign, U> AddAssign for Length<T, U> { + fn add_assign(&mut self, other: Self) { + self.0 += other.0; + } +} + +// length - length +impl<T: Sub, U> Sub for Length<T, U> { + type Output = Length<T::Output, U>; + + fn sub(self, other: Length<T, U>) -> Self::Output { + Length::new(self.0 - other.0) + } +} + +// length -= length +impl<T: SubAssign, U> SubAssign for Length<T, U> { + fn sub_assign(&mut self, other: Self) { + self.0 -= other.0; + } +} + +// Saturating length + length and length - length. +impl<T: Saturating, U> Saturating for Length<T, U> { + fn saturating_add(self, other: Self) -> Self { + Length::new(self.0.saturating_add(other.0)) + } + + fn saturating_sub(self, other: Self) -> Self { + Length::new(self.0.saturating_sub(other.0)) + } +} + +// length / length +impl<Src, Dst, T: Div> Div<Length<T, Src>> for Length<T, Dst> { + type Output = Scale<T::Output, Src, Dst>; + + #[inline] + fn div(self, other: Length<T, Src>) -> Self::Output { + Scale::new(self.0 / other.0) + } +} + +// length * scalar +impl<T: Mul, U> Mul<T> for Length<T, U> { + type Output = Length<T::Output, U>; + + #[inline] + fn mul(self, scale: T) -> Self::Output { + Length::new(self.0 * scale) + } +} + +// length *= scalar +impl<T: Copy + Mul<T, Output = T>, U> MulAssign<T> for Length<T, U> { + #[inline] + fn mul_assign(&mut self, scale: T) { + *self = *self * scale + } +} + +// length / scalar +impl<T: Div, U> Div<T> for Length<T, U> { + type Output = Length<T::Output, U>; + + #[inline] + fn div(self, scale: T) -> Self::Output { + Length::new(self.0 / scale) + } +} + +// length /= scalar +impl<T: Copy + Div<T, Output = T>, U> DivAssign<T> for Length<T, U> { + #[inline] + fn div_assign(&mut self, scale: T) { + *self = *self / scale + } +} + +// length * scaleFactor +impl<Src, Dst, T: Mul> Mul<Scale<T, Src, Dst>> for Length<T, Src> { + type Output = Length<T::Output, Dst>; + + #[inline] + fn mul(self, scale: Scale<T, Src, Dst>) -> Self::Output { + Length::new(self.0 * scale.0) + } +} + +// length / scaleFactor +impl<Src, Dst, T: Div> Div<Scale<T, Src, Dst>> for Length<T, Dst> { + type Output = Length<T::Output, Src>; + + #[inline] + fn div(self, scale: Scale<T, Src, Dst>) -> Self::Output { + Length::new(self.0 / scale.0) + } +} + +// -length +impl<U, T: Neg> Neg for Length<T, U> { + type Output = Length<T::Output, U>; + + #[inline] + fn neg(self) -> Self::Output { + Length::new(-self.0) + } +} + +impl<T: PartialEq, U> PartialEq for Length<T, U> { + fn eq(&self, other: &Self) -> bool { + self.0.eq(&other.0) + } +} + +impl<T: PartialOrd, U> PartialOrd for Length<T, U> { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + self.0.partial_cmp(&other.0) + } +} + +impl<T: Eq, U> Eq for Length<T, U> {} + +impl<T: Ord, U> Ord for Length<T, U> { + fn cmp(&self, other: &Self) -> Ordering { + self.0.cmp(&other.0) + } +} + +impl<T: Zero, U> Zero for Length<T, U> { + #[inline] + fn zero() -> Self { + Length::new(Zero::zero()) + } +} + +impl<U, T: ApproxEq<T>> ApproxEq<T> for Length<T, U> { + #[inline] + fn approx_epsilon() -> T { + T::approx_epsilon() + } + + #[inline] + fn approx_eq_eps(&self, other: &Length<T, U>, approx_epsilon: &T) -> bool { + self.0.approx_eq_eps(&other.0, approx_epsilon) + } +} + +#[cfg(test)] +mod tests { + use super::Length; + use crate::num::Zero; + + use crate::scale::Scale; + use core::f32::INFINITY; + use num_traits::Saturating; + + enum Inch {} + enum Mm {} + enum Cm {} + enum Second {} + + #[cfg(feature = "serde")] + mod serde { + use super::*; + + extern crate serde_test; + use self::serde_test::assert_tokens; + use self::serde_test::Token; + + #[test] + fn test_length_serde() { + let one_cm: Length<f32, Mm> = Length::new(10.0); + + assert_tokens(&one_cm, &[Token::F32(10.0)]); + } + } + + #[test] + fn test_clone() { + // A cloned Length is a separate length with the state matching the + // original Length at the point it was cloned. + let mut variable_length: Length<f32, Inch> = Length::new(12.0); + + let one_foot = variable_length.clone(); + variable_length.0 = 24.0; + + assert_eq!(one_foot.get(), 12.0); + assert_eq!(variable_length.get(), 24.0); + } + + #[test] + fn test_add() { + let length1: Length<u8, Mm> = Length::new(250); + let length2: Length<u8, Mm> = Length::new(5); + + assert_eq!((length1 + length2).get(), 255); + assert_eq!((length1 + &length2).get(), 255); + } + + #[test] + fn test_sum() { + type L = Length<f32, Mm>; + let lengths = [L::new(1.0), L::new(2.0), L::new(3.0)]; + + assert_eq!(lengths.iter().sum::<L>(), L::new(6.0)); + } + + #[test] + fn test_addassign() { + let one_cm: Length<f32, Mm> = Length::new(10.0); + let mut measurement: Length<f32, Mm> = Length::new(5.0); + + measurement += one_cm; + + assert_eq!(measurement.get(), 15.0); + } + + #[test] + fn test_sub() { + let length1: Length<u8, Mm> = Length::new(250); + let length2: Length<u8, Mm> = Length::new(5); + + let result = length1 - length2; + + assert_eq!(result.get(), 245); + } + + #[test] + fn test_subassign() { + let one_cm: Length<f32, Mm> = Length::new(10.0); + let mut measurement: Length<f32, Mm> = Length::new(5.0); + + measurement -= one_cm; + + assert_eq!(measurement.get(), -5.0); + } + + #[test] + fn test_saturating_add() { + let length1: Length<u8, Mm> = Length::new(250); + let length2: Length<u8, Mm> = Length::new(6); + + let result = length1.saturating_add(length2); + + assert_eq!(result.get(), 255); + } + + #[test] + fn test_saturating_sub() { + let length1: Length<u8, Mm> = Length::new(5); + let length2: Length<u8, Mm> = Length::new(10); + + let result = length1.saturating_sub(length2); + + assert_eq!(result.get(), 0); + } + + #[test] + fn test_division_by_length() { + // Division results in a Scale from denominator units + // to numerator units. + let length: Length<f32, Cm> = Length::new(5.0); + let duration: Length<f32, Second> = Length::new(10.0); + + let result = length / duration; + + let expected: Scale<f32, Second, Cm> = Scale::new(0.5); + assert_eq!(result, expected); + } + + #[test] + fn test_multiplication() { + let length_mm: Length<f32, Mm> = Length::new(10.0); + let cm_per_mm: Scale<f32, Mm, Cm> = Scale::new(0.1); + + let result = length_mm * cm_per_mm; + + let expected: Length<f32, Cm> = Length::new(1.0); + assert_eq!(result, expected); + } + + #[test] + fn test_multiplication_with_scalar() { + let length_mm: Length<f32, Mm> = Length::new(10.0); + + let result = length_mm * 2.0; + + let expected: Length<f32, Mm> = Length::new(20.0); + assert_eq!(result, expected); + } + + #[test] + fn test_multiplication_assignment() { + let mut length: Length<f32, Mm> = Length::new(10.0); + + length *= 2.0; + + let expected: Length<f32, Mm> = Length::new(20.0); + assert_eq!(length, expected); + } + + #[test] + fn test_division_by_scalefactor() { + let length: Length<f32, Cm> = Length::new(5.0); + let cm_per_second: Scale<f32, Second, Cm> = Scale::new(10.0); + + let result = length / cm_per_second; + + let expected: Length<f32, Second> = Length::new(0.5); + assert_eq!(result, expected); + } + + #[test] + fn test_division_by_scalar() { + let length: Length<f32, Cm> = Length::new(5.0); + + let result = length / 2.0; + + let expected: Length<f32, Cm> = Length::new(2.5); + assert_eq!(result, expected); + } + + #[test] + fn test_division_assignment() { + let mut length: Length<f32, Mm> = Length::new(10.0); + + length /= 2.0; + + let expected: Length<f32, Mm> = Length::new(5.0); + assert_eq!(length, expected); + } + + #[test] + fn test_negation() { + let length: Length<f32, Cm> = Length::new(5.0); + + let result = -length; + + let expected: Length<f32, Cm> = Length::new(-5.0); + assert_eq!(result, expected); + } + + #[test] + fn test_cast() { + let length_as_i32: Length<i32, Cm> = Length::new(5); + + let result: Length<f32, Cm> = length_as_i32.cast(); + + let length_as_f32: Length<f32, Cm> = Length::new(5.0); + assert_eq!(result, length_as_f32); + } + + #[test] + fn test_equality() { + let length_5_point_0: Length<f32, Cm> = Length::new(5.0); + let length_5_point_1: Length<f32, Cm> = Length::new(5.1); + let length_0_point_1: Length<f32, Cm> = Length::new(0.1); + + assert!(length_5_point_0 == length_5_point_1 - length_0_point_1); + assert!(length_5_point_0 != length_5_point_1); + } + + #[test] + fn test_order() { + let length_5_point_0: Length<f32, Cm> = Length::new(5.0); + let length_5_point_1: Length<f32, Cm> = Length::new(5.1); + let length_0_point_1: Length<f32, Cm> = Length::new(0.1); + + assert!(length_5_point_0 < length_5_point_1); + assert!(length_5_point_0 <= length_5_point_1); + assert!(length_5_point_0 <= length_5_point_1 - length_0_point_1); + assert!(length_5_point_1 > length_5_point_0); + assert!(length_5_point_1 >= length_5_point_0); + assert!(length_5_point_0 >= length_5_point_1 - length_0_point_1); + } + + #[test] + fn test_zero_add() { + type LengthCm = Length<f32, Cm>; + let length: LengthCm = Length::new(5.0); + + let result = length - LengthCm::zero(); + + assert_eq!(result, length); + } + + #[test] + fn test_zero_division() { + type LengthCm = Length<f32, Cm>; + let length: LengthCm = Length::new(5.0); + let length_zero: LengthCm = Length::zero(); + + let result = length / length_zero; + + let expected: Scale<f32, Cm, Cm> = Scale::new(INFINITY); + assert_eq!(result, expected); + } +} |