From 77610afe09b65fd2ff8215d3e0e461af3dc47fdc Mon Sep 17 00:00:00 2001
From: Chen-Pang He <chen.pang.he@jdh8.org>
Date: Sun, 12 May 2024 05:09:15 +0800
Subject: [PATCH 1/2] Implement NaN propagating minmax with TotalOrder and
FloatCore
---
src/float.rs | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/src/float.rs b/src/float.rs
index d0d21a5..bb1e9ce 100644
--- a/src/float.rs
+++ b/src/float.rs
@@ -2245,7 +2245,7 @@ float_const_impl! {
/// Trait for floating point numbers that provide an implementation
/// of the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
/// floating point standard.
-pub trait TotalOrder {
+pub trait TotalOrder: FloatCore {
/// Return the ordering between `self` and `other`.
///
/// Unlike the standard partial comparison between floating point numbers,
@@ -2297,6 +2297,32 @@ pub trait TotalOrder {
/// check_lt(-0.0_f64, 0.0_f64);
/// ```
fn total_cmp(&self, other: &Self) -> Ordering;
+
+ /// Get the maximum of two numbers, propagating NaN
+ ///
+ /// For this operation, -0.0 is considered to be less than +0.0 as
+ /// specified in IEEE 754-2019.
+ #[must_use]
+ fn maximum(self, other: Self) -> Self {
+ match (self.is_nan(), other.is_nan()) {
+ (true, _) => self,
+ (_, true) => other,
+ _ => core::cmp::max_by(self, other, Self::total_cmp),
+ }
+ }
+
+ /// Get the minimum of two numbers, propagating NaN
+ ///
+ /// For this operation, -0.0 is considered to be less than +0.0 as
+ /// specified in IEEE 754-2019.
+ #[must_use]
+ fn minimum(self, other: Self) -> Self {
+ match (self.is_nan(), other.is_nan()) {
+ (true, _) => self,
+ (_, true) => other,
+ _ => core::cmp::min_by(self, other, Self::total_cmp),
+ }
+ }
}
macro_rules! totalorder_impl {
($T:ident, $I:ident, $U:ident, $bits:expr) => {
From 180299c1922dc911749c3c382f0ac8bbeb64fee2 Mon Sep 17 00:00:00 2001
From: Chen-Pang He <chen.pang.he@jdh8.org>
Date: Thu, 16 May 2024 00:52:31 +0800
Subject: [PATCH 2/2] Move Self: FloatCore requirement to (min|max)imum
functions to avoid a breaking change
---
src/float.rs | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/src/float.rs b/src/float.rs
index bb1e9ce..d38dd1a 100644
--- a/src/float.rs
+++ b/src/float.rs
@@ -2245,7 +2245,7 @@ float_const_impl! {
/// Trait for floating point numbers that provide an implementation
/// of the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
/// floating point standard.
-pub trait TotalOrder: FloatCore {
+pub trait TotalOrder {
/// Return the ordering between `self` and `other`.
///
/// Unlike the standard partial comparison between floating point numbers,
@@ -2303,7 +2303,10 @@ pub trait TotalOrder: FloatCore {
/// For this operation, -0.0 is considered to be less than +0.0 as
/// specified in IEEE 754-2019.
#[must_use]
- fn maximum(self, other: Self) -> Self {
+ fn maximum(self, other: Self) -> Self
+ where
+ Self: FloatCore,
+ {
match (self.is_nan(), other.is_nan()) {
(true, _) => self,
(_, true) => other,
@@ -2316,7 +2319,10 @@ pub trait TotalOrder: FloatCore {
/// For this operation, -0.0 is considered to be less than +0.0 as
/// specified in IEEE 754-2019.
#[must_use]
- fn minimum(self, other: Self) -> Self {
+ fn minimum(self, other: Self) -> Self
+ where
+ Self: FloatCore,
+ {
match (self.is_nan(), other.is_nan()) {
(true, _) => self,
(_, true) => other,