[String] Fast paths for hasPrefix and hasSuffix

Author: ikesyo

Foundation/NSString.swift

@@ -1428,29 +1428,29 @@ extension String : _NSBridgeable, _CFBridgeable {
 #if !(os(OSX) || os(iOS))
 extension String {
     public func hasPrefix(_ prefix: String) -> Bool {
+        if prefix.isEmpty {
+            return true
+        }
+
         let cfstring = self._cfObject
         let range = CFRangeMake(0, CFStringGetLength(cfstring))
         let opts = CFStringCompareFlags(
             kCFCompareAnchored | kCFCompareNonliteral)
-        if prefix.isEmpty {
-            return true
-        } else {
-            return CFStringFindWithOptions(cfstring, prefix._cfObject,
-                                       range, opts, nil)
-        } 
+        return CFStringFindWithOptions(cfstring, prefix._cfObject,
+                                   range, opts, nil)
     }
 
     public func hasSuffix(_ suffix: String) -> Bool {
+        if suffix.isEmpty {
+            return true
+        }
+
         let cfstring = self._cfObject
         let range = CFRangeMake(0, CFStringGetLength(cfstring))
         let opts = CFStringCompareFlags(
             kCFCompareAnchored | kCFCompareBackwards | kCFCompareNonliteral)
-        if suffix.isEmpty {
-            return true
-        } else {
-            return CFStringFindWithOptions(cfstring, suffix._cfObject,
-                                       range, opts, nil)
-        }    
+        return CFStringFindWithOptions(cfstring, suffix._cfObject,
+                                   range, opts, nil)
     }
 }
 #endif