decodeURI and decodeURIComponent speedup

src/uri.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 72 matching lines @@
   var z = cc2 & 63;
   var octets = new $Array(4);
   octets[0] = (u >> 2) + 240;
   octets[1] = (((u & 3) << 4) | w) + 128;
   octets[2] = ((x << 4) | y) + 128;
   octets[3] = z + 128;
   return URIEncodeOctets(octets, result, index);
 }
 
 
-function URIHexCharsToCharCode(ch1, ch2) {
-  if (HexValueOf(ch1) == -1 || HexValueOf(ch2) == -1) {
+function URIHexCharsToCharCode(highChar, lowChar) {
+  var highCode = HexValueOf(highChar);
+  var lowCode = HexValueOf(lowChar);
+  if (highCode == -1 || lowCode == -1) {
     throw new $URIError("URI malformed");
   }
-  return HexStrToCharCode(ch1 + ch2);
+  return (highCode << 4) + lowCode;
 }
 
 
 function URIDecodeOctets(octets, result, index) {
   var value;
   var o0 = octets[0];
   if (o0 < 0x80) {
     value = o0;
   } else if (o0 < 0xc2) {
     throw new $URIError("URI malformed");
@@ skipping 81 matching lines @@
 
 // ECMA-262, section 15.1.3
 function Decode(uri, reserved) {
   var uriLength = uri.length;
   var result = new $Array(uriLength);
   var index = 0;
   for (var k = 0; k < uriLength; k++) {
     var ch = uri.charAt(k);
     if (ch == '%') {
       if (k + 2 >= uriLength) throw new $URIError("URI malformed");
-      var cc = URIHexCharsToCharCode(uri.charAt(++k), uri.charAt(++k));
+      var cc = URIHexCharsToCharCode(uri.charCodeAt(++k), uri.charCodeAt(++k));
       if (cc >> 7) {
         var n = 0;
         while (((cc << ++n) & 0x80) != 0) ;
         if (n == 1 || n > 4) throw new $URIError("URI malformed");
         var octets = new $Array(n);
         octets[0] = cc;
         if (k + 3 * (n - 1) >= uriLength) throw new $URIError("URI malformed");
         for (var i = 1; i < n; i++) {
           if (uri.charAt(++k) != '%') throw new $URIError("URI malformed");
-          octets[i] = URIHexCharsToCharCode(uri.charAt(++k), uri.charAt(++k));
+          octets[i] = URIHexCharsToCharCode(uri.charCodeAt(++k), uri.charCodeAt(++k));
         }
         index = URIDecodeOctets(octets, result, index);
       } else {
         if (reserved(cc)) {
           result[index++] = 37; // Char code of '%'.
           result[index++] = uri.charCodeAt(k - 1);
           result[index++] = uri.charCodeAt(k);
         } else {
           result[index++] = cc;
         }
@@ skipping 98 matching lines @@
     if (cc == 126) return true;
 
     return false;
   };
 
   var string = ToString(component);
   return Encode(string, unescapePredicate);
 }
 
 
-function HexValueOf(c) {
-  var code = c.charCodeAt(0);
-
+function HexValueOf(code) {
   // 0-9
   if (code >= 48 && code <= 57) return code - 48;
   // A-F
   if (code >= 65 && code <= 70) return code - 55;
   // a-f
   if (code >= 97 && code <= 102) return code - 87;
 
   return -1;
 }
 
 
 // Convert a character code to 4-digit hex string representation
 // 64 -> 0040, 62234 -> F31A.
 function CharCodeToHex4Str(cc) {
   var r = "";
   if (hexCharArray === 0) {
     hexCharArray = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
                     "A", "B", "C", "D", "E", "F"];
   }
   for (var i = 0; i < 4; ++i) {
     var c = hexCharArray[cc & 0x0F];
     r = c + r;
     cc = cc >>> 4;
   }
   return r;
 }
 
 
-// Converts hex string to char code. Not efficient.
-function HexStrToCharCode(s) {
-  var m = 0;
-  var r = 0;
-  for (var i = s.length - 1; i >= 0; --i) {
-    r = r + (HexValueOf(s.charAt(i)) << m);
-    m = m + 4;
-  }
-  return r;
-}
-
-
 // Returns true if all digits in string s are valid hex numbers
 function IsValidHex(s) {
   for (var i = 0; i < s.length; ++i) {
     var cc = s.charCodeAt(i);
     if ((48 <= cc && cc <= 57) || (65 <= cc && cc <= 70) || (97 <= cc && cc <= 102)) {
       // '0'..'9', 'A'..'F' and 'a' .. 'f'.
     } else {
       return false;
     }
   }
@@ skipping 24 matching lines @@
     "escape", URIEscape,
     "unescape", URIUnescape,
     "decodeURI", URIDecode,
     "decodeURIComponent", URIDecodeComponent,
     "encodeURI", URIEncode,
     "encodeURIComponent", URIEncodeComponent
   ));
 }
 
 SetupURI();