From d43bf539482b8244690824e0880a80ed578d5429 Mon Sep 17 00:00:00 2001
From: Ulrik Sverdrup <root@localhost>
Date: Tue, 9 Jun 2015 11:23:22 +0200
Subject: Add str::split_at

Implement RFC rust-lang/rfcs#1123

Add str method str::split_at(mid: usize) -> (&str, &str).
---
 src/libcore/str/mod.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'src/libcore')

diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 11ca6e332b5..4db64a3097e 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1517,6 +1517,7 @@ pub trait StrExt {
     fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
         where P::Searcher: ReverseSearcher<'a>;
     fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
+    fn split_at(&self, mid: usize) -> (&str, &str);
     fn slice_shift_char<'a>(&'a self) -> Option<(char, &'a str)>;
     fn subslice_offset(&self, inner: &str) -> usize;
     fn as_ptr(&self) -> *const u8;
@@ -1809,6 +1810,18 @@ impl StrExt for str {
         self.find(pat)
     }
 
+    fn split_at(&self, mid: usize) -> (&str, &str) {
+        // is_char_boundary checks that the index is in [0, .len()]
+        if self.is_char_boundary(mid) {
+            unsafe {
+                (self.slice_unchecked(0, mid),
+                 self.slice_unchecked(mid, self.len()))
+            }
+        } else {
+            slice_error_fail(self, 0, mid)
+        }
+    }
+
     #[inline]
     fn slice_shift_char(&self) -> Option<(char, &str)> {
         if self.is_empty() {
-- 
cgit 1.4.1-3-g733a5