From 739ba0417ae6477ffc9c5e8298b5075725d52420 Mon Sep 17 00:00:00 2001
From: Adrian Friedli <adi@koalatux.ch>
Date: Sun, 24 Feb 2019 00:22:41 +0100
Subject: implement nth_back for Windows

---
 src/libcore/slice/mod.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'src/libcore/slice')

diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index acca9748372..b048a12e402 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -3835,6 +3835,19 @@ impl<'a, T> DoubleEndedIterator for Windows<'a, T> {
             ret
         }
     }
+
+    #[inline]
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        let (end, overflow) = self.v.len().overflowing_sub(n);
+        if end < self.size || overflow {
+            self.v = &[];
+            None
+        } else {
+            let ret = &self.v[end-self.size..end];
+            self.v = &self.v[..end-1];
+            Some(ret)
+        }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-- 
cgit 1.4.1-3-g733a5