1 files changed, 104 insertions, 0 deletions
diff --git a/src/v1_37.rs b/src/v1_37.rs
new file mode 100644
index 0000000..70d477b
--- /dev/null
+++ b/src/v1_37.rs
@@ -0,0 +1,104 @@
+use crate::traits::Sealed;
+use core::{
+    cell::Cell,
+    ops::{Bound, RangeBounds},
+    ptr,
+};
+
+pub trait Cell_v1_37<T>: Sealed<Cell<T>> {
+    fn from_mut(t: &mut T) -> &Cell<T>;
+}
+
+impl<T> Cell_v1_37<T> for Cell<T> {
+    #[inline]
+    fn from_mut(t: &mut T) -> &Cell<T> {
+        unsafe { &*(t as *mut T as *const Cell<T>) }
+    }
+}
+
+pub trait Cell_v1_37_<T>: Sealed<Cell<[T]>> {
+    fn as_slice_of_cells(&self) -> &[Cell<T>];
+}
+
+impl<T> Cell_v1_37_<T> for Cell<[T]> {
+    fn as_slice_of_cells(&self) -> &[Cell<T>] {
+        unsafe { &*(self as *const Cell<[T]> as *const [Cell<T>]) }
+    }
+}
+
+pub trait Option_v1_37<T>: Sealed<Option<T>> {
+    fn xor(self, optb: Option<T>) -> Option<T>;
+}
+
+impl<T> Option_v1_37<T> for Option<T> {
+    #[inline]
+    fn xor(self, optb: Option<T>) -> Option<T> {
+        match (self, optb) {
+            (Some(a), None) => Some(a),
+            (None, Some(b)) => Some(b),
+            _ => None,
+        }
+    }
+}
+
+pub trait Slice_v1_37<T>: Sealed<[T]> {
+    fn copy_within<R: RangeBounds<usize>>(&mut self, src: R, dest: usize)
+    where
+        T: Copy;
+}
+
+impl<T> Slice_v1_37<T> for [T] {
+    fn copy_within<R: RangeBounds<usize>>(&mut self, src: R, dest: usize)
+    where
+        T: Copy,
+    {
+        let src_start = match src.start_bound() {
+            Bound::Included(&n) => n,
+            Bound::Excluded(&n) => n
+                .checked_add(1)
+                .unwrap_or_else(|| slice_index_overflow_fail()),
+            Bound::Unbounded => 0,
+        };
+        let src_end = match src.end_bound() {
+            Bound::Included(&n) => n
+                .checked_add(1)
+                .unwrap_or_else(|| slice_index_overflow_fail()),
+            Bound::Excluded(&n) => n,
+            Bound::Unbounded => self.len(),
+        };
+        assert!(src_start <= src_end, "src end is before src start");
+        assert!(src_end <= self.len(), "src is out of bounds");
+        let count = src_end - src_start;
+        assert!(dest <= self.len() - count, "dest is out of bounds");
+        unsafe {
+            ptr::copy(
+                self.as_ptr().add(src_start),
+                self.as_mut_ptr().add(dest),
+                count,
+            );
+        }
+    }
+}
+
+#[inline(never)]
+#[cold]
+fn slice_index_overflow_fail() -> ! {
+    panic!("attempted to index slice up to maximum usize");
+}
+
+pub trait DoubleEndedIterator_v1_37: DoubleEndedIterator {
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item>;
+}
+
+impl<Iter: DoubleEndedIterator> DoubleEndedIterator_v1_37 for Iter {
+    #[inline]
+    fn nth_back(&mut self, mut n: usize) -> Option<Self::Item> {
+        for x in self.rev() {
+            if n == 0 {
+                return Some(x);
+            }
+            n -= 1;
+        }
+        None
+    }
+}