/// Compare and return the minimum of two values.
///
+/// Returns the first argument if the comparison determines them to be equal.
+///
/// # Examples
///
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn min<T: Ord>(v1: T, v2: T) -> T {
- if v1 < v2 { v1 } else { v2 }
+ if v1 <= v2 { v1 } else { v2 }
}
/// Compare and return the maximum of two values.
///
+/// Returns the second argument if the comparison determines them to be equal.
+///
/// # Examples
///
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn max<T: Ord>(v1: T, v2: T) -> T {
- if v1 > v2 { v1 } else { v2 }
+ if v2 >= v1 { v2 } else { v1 }
}
/// Compare and return the minimum of two values if there is one.
/// Compare and return the maximum of two values if there is one.
///
-/// Returns the first argument if the comparison determines them to be equal.
+/// Returns the second argument if the comparison determines them to be equal.
///
/// # Examples
///
#[unstable(feature = "core")]
pub fn partial_max<T: PartialOrd>(v1: T, v2: T) -> Option<T> {
match v1.partial_cmp(&v2) {
- Some(Less) => Some(v2),
- Some(Equal) | Some(Greater) => Some(v1),
+ Some(Equal) | Some(Less) => Some(v2),
+ Some(Greater) => Some(v1),
None => None
}
}
/// Consumes the entire iterator to return the maximum element.
///
+ /// Returns the rightmost element if the comparison determines two elements
+ /// to be equally maximum.
+ ///
/// # Examples
///
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn max(self) -> Option<Self::Item> where Self: Sized, Self::Item: Ord
{
- self.fold(None, |max, x| {
+ self.fold(None, |max, y| {
match max {
- None => Some(x),
- Some(y) => Some(cmp::max(x, y))
+ None => Some(y),
+ Some(x) => Some(cmp::max(x, y))
}
})
}
/// Consumes the entire iterator to return the minimum element.
///
+ /// Returns the leftmost element if the comparison determines two elements
+ /// to be equally minimum.
+ ///
/// # Examples
///
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn min(self) -> Option<Self::Item> where Self: Sized, Self::Item: Ord
{
- self.fold(None, |min, x| {
+ self.fold(None, |min, y| {
match min {
- None => Some(x),
- Some(y) => Some(cmp::min(x, y))
+ None => Some(y),
+ Some(x) => Some(cmp::min(x, y))
}
})
}
Some(x) => {
match self.next() {
None => return OneElement(x),
- Some(y) => if x < y {(x, y)} else {(y,x)}
+ Some(y) => if x <= y {(x, y)} else {(y, x)}
}
}
};
None => {
if first < min {
min = first;
- } else if first > max {
+ } else if first >= max {
max = first;
}
break;
}
Some(x) => x
};
- if first < second {
- if first < min {min = first;}
- if max < second {max = second;}
+ if first <= second {
+ if first < min { min = first }
+ if second >= max { max = second }
} else {
- if second < min {min = second;}
- if max < first {max = first;}
+ if second < min { min = second }
+ if first >= max { max = first }
}
}
/// Return the element that gives the maximum value from the
/// specified function.
///
+ /// Returns the rightmost element if the comparison determines two elements
+ /// to be equally maximum.
+ ///
/// # Examples
///
/// ```
Self: Sized,
F: FnMut(&Self::Item) -> B,
{
- self.fold(None, |max: Option<(Self::Item, B)>, x| {
- let x_val = f(&x);
+ self.fold(None, |max: Option<(Self::Item, B)>, y| {
+ let y_val = f(&y);
match max {
- None => Some((x, x_val)),
- Some((y, y_val)) => if x_val > y_val {
- Some((x, x_val))
- } else {
+ None => Some((y, y_val)),
+ Some((x, x_val)) => if y_val >= x_val {
Some((y, y_val))
+ } else {
+ Some((x, x_val))
}
}
}).map(|(x, _)| x)
/// Return the element that gives the minimum value from the
/// specified function.
///
+ /// Returns the leftmost element if the comparison determines two elements
+ /// to be equally minimum.
+ ///
/// # Examples
///
/// ```
Self: Sized,
F: FnMut(&Self::Item) -> B,
{
- self.fold(None, |min: Option<(Self::Item, B)>, x| {
- let x_val = f(&x);
+ self.fold(None, |min: Option<(Self::Item, B)>, y| {
+ let y_val = f(&y);
match min {
- None => Some((x, x_val)),
- Some((y, y_val)) => if x_val < y_val {
+ None => Some((y, y_val)),
+ Some((x, x_val)) => if x_val <= y_val {
Some((x, x_val))
} else {
Some((y, y_val))
--- /dev/null
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// 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.
+
+#![feature(core)]
+use std::fmt::Debug;
+use std::cmp::{self, PartialOrd, Ordering};
+use std::iter::MinMaxResult::MinMax;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+struct Foo {
+ n: u8,
+ name: &'static str
+}
+
+impl PartialOrd for Foo {
+ fn partial_cmp(&self, other: &Foo) -> Option<Ordering> {
+ Some(self.cmp(other))
+ }
+}
+
+impl Ord for Foo {
+ fn cmp(&self, other: &Foo) -> Ordering {
+ self.n.cmp(&other.n)
+ }
+}
+
+fn main() {
+ let a = Foo { n: 4, name: "a" };
+ let b = Foo { n: 4, name: "b" };
+ let c = Foo { n: 8, name: "c" };
+ let d = Foo { n: 8, name: "d" };
+ let e = Foo { n: 22, name: "e" };
+ let f = Foo { n: 22, name: "f" };
+
+ let data = [a, b, c, d, e, f];
+
+ // `min` should return the left when the values are equal
+ assert_eq!(data.iter().min(), Some(&a));
+ assert_eq!(data.iter().min_by(|a| a.n), Some(&a));
+ assert_eq!(cmp::min(a, b), a);
+ assert_eq!(cmp::min(b, a), b);
+ assert_eq!(cmp::partial_min(a, b), Some(a));
+ assert_eq!(cmp::partial_min(b, a), Some(b));
+
+ // `max` should return the right when the values are equal
+ assert_eq!(data.iter().max(), Some(&f));
+ assert_eq!(data.iter().max_by(|a| a.n), Some(&f));
+ assert_eq!(cmp::max(e, f), f);
+ assert_eq!(cmp::max(f, e), e);
+ assert_eq!(cmp::partial_max(e, f), Some(f));
+ assert_eq!(cmp::partial_max(f, e), Some(e));
+
+ // Similar for `min_max`
+ assert_eq!(data.iter().min_max(), MinMax(&a, &f));
+ assert_eq!(data[1..5].iter().min_max(), MinMax(&b, &e));
+ assert_eq!(data[2..4].iter().min_max(), MinMax(&c, &d));
+
+ let mut presorted = data.to_vec();
+ presorted.sort();
+ assert_stable(&presorted);
+
+ let mut presorted = data.to_vec();
+ presorted.sort_by(|a, b| a.cmp(b));
+ assert_stable(&presorted);
+
+ // Assert that sorted and min/max are the same
+ fn assert_stable<T: Ord + Debug>(presorted: &[T]) {
+ for slice in presorted.windows(2) {
+ let a = &slice[0];
+ let b = &slice[1];
+
+ assert_eq!(a, cmp::min(a, b));
+ assert_eq!(b, cmp::max(a, b));
+ }
+ }
+}
projects / rust.git / commitdiff