diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs index ec6525485f7a1..174ceb6b8a7e6 100644 --- a/src/libcore/cmp.rs +++ b/src/libcore/cmp.rs @@ -481,6 +481,32 @@ pub trait Ord: Eq + PartialOrd { where Self: Sized { if self <= other { self } else { other } } + + /// Returns max if self is greater than max, and min if self is less than min. + /// Otherwise this will return self. Panics if min > max. + /// + /// # Examples + /// + /// ``` + /// #![feature(clamp)] + /// + /// assert!((-3).clamp(-2, 1) == -2); + /// assert!(0.clamp(-2, 1) == 0); + /// assert!(2.clamp(-2, 1) == 1); + /// ``` + #[unstable(feature = "clamp", issue = "44095")] + fn clamp(self, min: Self, max: Self) -> Self + where Self: Sized { + assert!(min <= max); + if self < min { + min + } + else if self > max { + max + } else { + self + } + } } #[stable(feature = "rust1", since = "1.0.0")] diff --git a/src/libstd/f32.rs b/src/libstd/f32.rs index 0135cd0a588cf..18bc27faa8227 100644 --- a/src/libstd/f32.rs +++ b/src/libstd/f32.rs @@ -1080,6 +1080,26 @@ impl f32 { 0.5 * ((2.0 * self) / (1.0 - self)).ln_1p() } + /// Returns max if self is greater than max, and min if self is less than min. + /// Otherwise this returns self. Panics if min > max, min equals NaN, or max equals NaN. + /// + /// # Examples + /// + /// ``` + /// assert!((-3.0f32).clamp(-2.0f32, 1.0f32) == -2.0f32); + /// assert!((0.0f32).clamp(-2.0f32, 1.0f32) == 0.0f32); + /// assert!((2.0f32).clamp(-2.0f32, 1.0f32) == 1.0f32); + /// ``` + #[unstable(feature = "clamp", issue = "44095")] + #[inline] + pub fn clamp(self, min: f32, max: f32) -> f32 { + assert!(min <= max); + let mut x = self; + if x < min { x = min; } + if x > max { x = max; } + x + } + /// Raw transmutation to `u32`. /// /// Converts the `f32` into its raw memory representation, diff --git a/src/libstd/f64.rs b/src/libstd/f64.rs index d73d7cd2c7bd1..b04ba9eabdbb3 100644 --- a/src/libstd/f64.rs +++ b/src/libstd/f64.rs @@ -970,6 +970,26 @@ impl f64 { 0.5 * ((2.0 * self) / (1.0 - self)).ln_1p() } + /// Returns max if self is greater than max, and min if self is less than min. + /// Otherwise this returns self. Panics if min > max, min equals NaN, or max equals NaN. + /// + /// # Examples + /// + /// ``` + /// assert!((-3.0f64).clamp(-2.0f64, 1.0f64) == -2.0f64); + /// assert!((0.0f64).clamp(-2.0f64, 1.0f64) == 0.0f64); + /// assert!((2.0f64).clamp(-2.0f64, 1.0f64) == 1.0f64); + /// ``` + #[unstable(feature = "clamp", issue = "44095")] + #[inline] + pub fn clamp(self, min: f64, max: f64) -> f64 { + assert!(min <= max); + let mut x = self; + if x < min { x = min; } + if x > max { x = max; } + x + } + // Solaris/Illumos requires a wrapper around log, log2, and log10 functions // because of their non-standard behavior (e.g. log(-n) returns -Inf instead // of expected NaN).