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Auto merge of rust-lang#79473 - m-ou-se:clamp-in-core, r=m-ou-se
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Move {f32,f64}::clamp to core.

`clamp` was recently stabilized (tracking issue: rust-lang#44095). But although `Ord::clamp` was added in `core` (because `Ord` is in `core`), the versions for the `f32` and `f64` primitives were added in `std` (together with `floor`, `sin`, etc.), not in `core` (together with `min`, `max`, `from_bits`, etc.).

This change moves them to `core`, such that `clamp` on floats is available in `no_std` programs as well.
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bors committed Dec 19, 2020
2 parents 1f5bc17 + 0523eeb commit c1d5843
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35 changes: 35 additions & 0 deletions library/core/src/num/f32.rs
Original file line number Diff line number Diff line change
Expand Up @@ -961,4 +961,39 @@ impl f32 {

left.cmp(&right)
}

/// Restrict a value to a certain interval unless it is NaN.
///
/// Returns `max` if `self` is greater than `max`, and `min` if `self` is
/// less than `min`. Otherwise this returns `self`.
///
/// Note that this function returns NaN if the initial value was NaN as
/// well.
///
/// # Panics
///
/// Panics if `min > max`, `min` is NaN, or `max` is NaN.
///
/// # Examples
///
/// ```
/// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
/// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
/// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
/// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
/// ```
#[must_use = "method returns a new number and does not mutate the original value"]
#[stable(feature = "clamp", since = "1.50.0")]
#[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
}
}
35 changes: 35 additions & 0 deletions library/core/src/num/f64.rs
Original file line number Diff line number Diff line change
Expand Up @@ -975,4 +975,39 @@ impl f64 {

left.cmp(&right)
}

/// Restrict a value to a certain interval unless it is NaN.
///
/// Returns `max` if `self` is greater than `max`, and `min` if `self` is
/// less than `min`. Otherwise this returns `self`.
///
/// Note that this function returns NaN if the initial value was NaN as
/// well.
///
/// # Panics
///
/// Panics if `min > max`, `min` is NaN, or `max` is NaN.
///
/// # Examples
///
/// ```
/// assert!((-3.0f64).clamp(-2.0, 1.0) == -2.0);
/// assert!((0.0f64).clamp(-2.0, 1.0) == 0.0);
/// assert!((2.0f64).clamp(-2.0, 1.0) == 1.0);
/// assert!((f64::NAN).clamp(-2.0, 1.0).is_nan());
/// ```
#[must_use = "method returns a new number and does not mutate the original value"]
#[stable(feature = "clamp", since = "1.50.0")]
#[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
}
}
35 changes: 0 additions & 35 deletions library/std/src/f32.rs
Original file line number Diff line number Diff line change
Expand Up @@ -879,39 +879,4 @@ impl f32 {
pub fn atanh(self) -> f32 {
0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
}

/// Restrict a value to a certain interval unless it is NaN.
///
/// Returns `max` if `self` is greater than `max`, and `min` if `self` is
/// less than `min`. Otherwise this returns `self`.
///
/// Note that this function returns NaN if the initial value was NaN as
/// well.
///
/// # Panics
///
/// Panics if `min > max`, `min` is NaN, or `max` is NaN.
///
/// # Examples
///
/// ```
/// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
/// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
/// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
/// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
/// ```
#[must_use = "method returns a new number and does not mutate the original value"]
#[stable(feature = "clamp", since = "1.50.0")]
#[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
}
}
35 changes: 0 additions & 35 deletions library/std/src/f64.rs
Original file line number Diff line number Diff line change
Expand Up @@ -882,41 +882,6 @@ impl f64 {
0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
}

/// Restrict a value to a certain interval unless it is NaN.
///
/// Returns `max` if `self` is greater than `max`, and `min` if `self` is
/// less than `min`. Otherwise this returns `self`.
///
/// Note that this function returns NaN if the initial value was NaN as
/// well.
///
/// # Panics
///
/// Panics if `min > max`, `min` is NaN, or `max` is NaN.
///
/// # Examples
///
/// ```
/// assert!((-3.0f64).clamp(-2.0, 1.0) == -2.0);
/// assert!((0.0f64).clamp(-2.0, 1.0) == 0.0);
/// assert!((2.0f64).clamp(-2.0, 1.0) == 1.0);
/// assert!((f64::NAN).clamp(-2.0, 1.0).is_nan());
/// ```
#[must_use = "method returns a new number and does not mutate the original value"]
#[stable(feature = "clamp", since = "1.50.0")]
#[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).
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