Auto merge of #95454 - randomicon00:fix95444, r=wesleywiser

[rust.git] / library / core / src / num / mod.rs

diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index f45b73b053364442ce346e03f5aec2ae4b09e61b..66193eaf5da73c1da12d93265d8b8b8f5a78636c 100644 (file)
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -890,6 +890,27 @@ impl usize {
     widening_impl! { usize, u128, 64, unsigned }
 }
 
+impl usize {
+    /// Returns an `usize` where every byte is equal to `x`.
+    #[inline]
+    pub(crate) const fn repeat_u8(x: u8) -> usize {
+        usize::from_ne_bytes([x; mem::size_of::<usize>()])
+    }
+
+    /// Returns an `usize` where every byte pair is equal to `x`.
+    #[inline]
+    pub(crate) const fn repeat_u16(x: u16) -> usize {
+        let mut r = 0usize;
+        let mut i = 0;
+        while i < mem::size_of::<usize>() {
+            // Use `wrapping_shl` to make it work on targets with 16-bit `usize`
+            r = r.wrapping_shl(16) | (x as usize);
+            i += 2;
+        }
+        r
+    }
+}
+
 /// A classification of floating point numbers.
 ///
 /// This `enum` is used as the return type for [`f32::classify`] and [`f64::classify`]. See
@@ -999,7 +1020,7 @@ fn checked_add(&self, other: u32) -> Option<Self> {
 }
 impl_helper_for! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
 
-/// Determins if a string of text of that length of that radix could be guaranteed to be
+/// Determines if a string of text of that length of that radix could be guaranteed to be
 /// stored in the given type T.
 /// Note that if the radix is known to the compiler, it is just the check of digits.len that
 /// is done at runtime.