1 files changed, 136 insertions, 0 deletions
diff --git a/servo/components/style/values/computed/percentage.rs b/servo/components/style/values/computed/percentage.rs
new file mode 100644
index 0000000000..994c01594a
--- /dev/null
+++ b/servo/components/style/values/computed/percentage.rs
@@ -0,0 +1,136 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Computed percentages.
+
+use crate::values::animated::ToAnimatedValue;
+use crate::values::generics::NonNegative;
+use crate::values::specified::percentage::ToPercentage;
+use crate::values::{serialize_normalized_percentage, CSSFloat};
+use crate::Zero;
+use std::fmt;
+use style_traits::{CssWriter, ToCss};
+
+/// A computed percentage.
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Debug,
+    Default,
+    Deserialize,
+    MallocSizeOf,
+    PartialEq,
+    PartialOrd,
+    Serialize,
+    SpecifiedValueInfo,
+    ToAnimatedValue,
+    ToAnimatedZero,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(C)]
+pub struct Percentage(pub CSSFloat);
+
+impl Percentage {
+    /// 100%
+    #[inline]
+    pub fn hundred() -> Self {
+        Percentage(1.)
+    }
+
+    /// Returns the absolute value for this percentage.
+    #[inline]
+    pub fn abs(&self) -> Self {
+        Percentage(self.0.abs())
+    }
+
+    /// Clamps this percentage to a non-negative percentage.
+    #[inline]
+    pub fn clamp_to_non_negative(self) -> Self {
+        Percentage(self.0.max(0.))
+    }
+}
+
+impl Zero for Percentage {
+    fn zero() -> Self {
+        Percentage(0.)
+    }
+
+    fn is_zero(&self) -> bool {
+        self.0 == 0.
+    }
+}
+
+impl ToPercentage for Percentage {
+    fn to_percentage(&self) -> CSSFloat {
+        self.0
+    }
+}
+
+impl std::ops::AddAssign for Percentage {
+    fn add_assign(&mut self, other: Self) {
+        self.0 += other.0
+    }
+}
+
+impl std::ops::Add for Percentage {
+    type Output = Self;
+
+    fn add(self, other: Self) -> Self {
+        Percentage(self.0 + other.0)
+    }
+}
+
+impl std::ops::Sub for Percentage {
+    type Output = Self;
+
+    fn sub(self, other: Self) -> Self {
+        Percentage(self.0 - other.0)
+    }
+}
+
+impl std::ops::Rem for Percentage {
+    type Output = Self;
+
+    fn rem(self, other: Self) -> Self {
+        Percentage(self.0 % other.0)
+    }
+}
+
+impl ToCss for Percentage {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        serialize_normalized_percentage(self.0, dest)
+    }
+}
+
+/// A wrapper over a `Percentage`, whose value should be clamped to 0.
+pub type NonNegativePercentage = NonNegative<Percentage>;
+
+impl NonNegativePercentage {
+    /// 100%
+    #[inline]
+    pub fn hundred() -> Self {
+        NonNegative(Percentage::hundred())
+    }
+}
+
+impl ToAnimatedValue for NonNegativePercentage {
+    type AnimatedValue = Percentage;
+
+    #[inline]
+    fn to_animated_value(self) -> Self::AnimatedValue {
+        self.0
+    }
+
+    #[inline]
+    fn from_animated_value(animated: Self::AnimatedValue) -> Self {
+        NonNegative(animated.clamp_to_non_negative())
+    }
+}