From 52949fbf1876ecd03303006c534a74c5e29bc90d Mon Sep 17 00:00:00 2001
From: Gary Linscott <glinscott@gmail.com>
Date: Sat, 6 Jul 2013 01:54:29 -0400
Subject: [PATCH] Faster check for ascii-space

Since ' ' is by far one of the most common characters, it is worthwhile
to put it first, and short-circuit the rest of the function.

On the same JSON benchmark, as the json_perf improvement, reading example.json
10 times from https://code.google.com/p/rapidjson/wiki/Performance.

Before: 0.16s
After: 0.11s
---
 src/libstd/char.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libstd/char.rs b/src/libstd/char.rs
index 6a9555f4efcd..47473c2faba6 100644
--- a/src/libstd/char.rs
+++ b/src/libstd/char.rs
@@ -82,7 +82,8 @@ pub fn is_uppercase(c: char) -> bool { general_category::Lu(c) }
 ///
 #[inline]
 pub fn is_whitespace(c: char) -> bool {
-    ('\x09' <= c && c <= '\x0d')
+    c == ' '
+        || ('\x09' <= c && c <= '\x0d')
         || general_category::Zs(c)
         || general_category::Zl(c)
         || general_category::Zp(c)