Harden a few builtins

src/uri.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 // -------------------------------------------------------------------
 
 // This file contains support for URI manipulations written in
 // JavaScript.
 
-// Lazily initialized.
-var hexCharArray = 0;
-var hexCharCodeArray = 0;
-
-
-function URIAddEncodedOctetToBuffer(octet, result, index) {
-  result[index++] = 37; // Char code of '%'.
-  result[index++] = hexCharCodeArray[octet >> 4];
-  result[index++] = hexCharCodeArray[octet & 0x0F];
-  return index;
-}
-
-
-function URIEncodeOctets(octets, result, index) {
-  if (hexCharCodeArray === 0) {
-    hexCharCodeArray = [48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
-                        65, 66, 67, 68, 69, 70];
-  }
-  index = URIAddEncodedOctetToBuffer(octets[0], result, index);
-  if (octets[1]) index = URIAddEncodedOctetToBuffer(octets[1], result, index);
-  if (octets[2]) index = URIAddEncodedOctetToBuffer(octets[2], result, index);
-  if (octets[3]) index = URIAddEncodedOctetToBuffer(octets[3], result, index);
-  return index;
-}
-
-
-function URIEncodeSingle(cc, result, index) {
-  var x = (cc >> 12) & 0xF;
-  var y = (cc >> 6) & 63;
-  var z = cc & 63;
-  var octets = new $Array(3);
-  if (cc <= 0x007F) {
-    octets[0] = cc;
-  } else if (cc <= 0x07FF) {
-    octets[0] = y + 192;
-    octets[1] = z + 128;
-  } else {
-    octets[0] = x + 224;
-    octets[1] = y + 128;
-    octets[2] = z + 128;
-  }
-  return URIEncodeOctets(octets, result, index);
-}
-
-
-function URIEncodePair(cc1 , cc2, result, index) {
-  var u = ((cc1 >> 6) & 0xF) + 1;
-  var w = (cc1 >> 2) & 0xF;
-  var x = cc1 & 3;
-  var y = (cc2 >> 6) & 0xF;
-  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(highChar, lowChar) {
-  var highCode = HexValueOf(highChar);
-  var lowCode = HexValueOf(lowChar);
-  if (highCode == -1 || lowCode == -1) {
-    throw new $URIError("URI malformed");
-  }
-  return (highCode << 4) | lowCode;
-}
-
-
-function URIDecodeOctets(octets, result, index) {
-  if (!IS_STRING(result)) throw new $URIError("Internal error");
-  var value;
-  var o0 = octets[0];
-  if (o0 < 0x80) {
-    value = o0;
-  } else if (o0 < 0xc2) {
-    throw new $URIError("URI malformed");
-  } else {
-    var o1 = octets[1];
-    if (o0 < 0xe0) {
-      var a = o0 & 0x1f;
-      if ((o1 < 0x80) || (o1 > 0xbf)) {
-        throw new $URIError("URI malformed");
-      }
-      var b = o1 & 0x3f;
-      value = (a << 6) + b;
-      if (value < 0x80 || value > 0x7ff) {
-        throw new $URIError("URI malformed");
-      }
+
+(function() {
+
+  // -------------------------------------------------------------------
+  // Define internal helper functions.
+
+  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;
+  }
+
+  // Does the char code correspond to an alpha-numeric char.
+  function isAlphaNumeric(cc) {
+    // a - z
+    if (97 <= cc && cc <= 122) return true;
+    // A - Z
+    if (65 <= cc && cc <= 90) return true;
+    // 0 - 9
+    if (48 <= cc && cc <= 57) return true;
+
+    return false;
+  }
+
+  //Lazily initialized.
+  var hexCharCodeArray = 0;
+
+  function URIAddEncodedOctetToBuffer(octet, result, index) {
+    result[index++] = 37; // Char code of '%'.
+    result[index++] = hexCharCodeArray[octet >> 4];
+    result[index++] = hexCharCodeArray[octet & 0x0F];
+    return index;
+  }
+
+  function URIEncodeOctets(octets, result, index) {
+    if (hexCharCodeArray === 0) {
+      hexCharCodeArray = [48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
+                          65, 66, 67, 68, 69, 70];
+    }
+    index = URIAddEncodedOctetToBuffer(octets[0], result, index);
+    if (octets[1]) index = URIAddEncodedOctetToBuffer(octets[1], result, index);
+    if (octets[2]) index = URIAddEncodedOctetToBuffer(octets[2], result, index);
+    if (octets[3]) index = URIAddEncodedOctetToBuffer(octets[3], result, index);
+    return index;
+  }
+
+  function URIEncodeSingle(cc, result, index) {
+    var x = (cc >> 12) & 0xF;
+    var y = (cc >> 6) & 63;
+    var z = cc & 63;
+    var octets = new $Array(3);
+    if (cc <= 0x007F) {
+      octets[0] = cc;
+    } else if (cc <= 0x07FF) {
+      octets[0] = y + 192;
+      octets[1] = z + 128;
     } else {
-      var o2 = octets[2];
-      if (o0 < 0xf0) {
-        var a = o0 & 0x0f;
+      octets[0] = x + 224;
+      octets[1] = y + 128;
+      octets[2] = z + 128;
+    }
+    return URIEncodeOctets(octets, result, index);
+  }
+
+  function URIEncodePair(cc1 , cc2, result, index) {
+    var u = ((cc1 >> 6) & 0xF) + 1;
+    var w = (cc1 >> 2) & 0xF;
+    var x = cc1 & 3;
+    var y = (cc2 >> 6) & 0xF;
+    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(highChar, lowChar) {
+    var highCode = HexValueOf(highChar);
+    var lowCode = HexValueOf(lowChar);
+    if (highCode == -1 || lowCode == -1) {
+      throw new $URIError("URI malformed");
+    }
+    return (highCode << 4) | lowCode;
+  }
+
+  // Callers must ensure that |result| is a sufficiently long sequential
+  // two-byte string!
+  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");
+    } else {
+      var o1 = octets[1];
+      if (o0 < 0xe0) {
+        var a = o0 & 0x1f;
         if ((o1 < 0x80) || (o1 > 0xbf)) {
           throw new $URIError("URI malformed");
         }
         var b = o1 & 0x3f;
-        if ((o2 < 0x80) || (o2 > 0xbf)) {
+        value = (a << 6) + b;
+        if (value < 0x80 || value > 0x7ff) {
           throw new $URIError("URI malformed");
         }
-        var c = o2 & 0x3f;
-        value = (a << 12) + (b << 6) + c;
-        if ((value < 0x800) || (value > 0xffff)) {
-          throw new $URIError("URI malformed");
-        }
       } else {
-        var o3 = octets[3];
-        if (o0 < 0xf8) {
-          var a = (o0 & 0x07);
+        var o2 = octets[2];
+        if (o0 < 0xf0) {
+          var a = o0 & 0x0f;
           if ((o1 < 0x80) || (o1 > 0xbf)) {
             throw new $URIError("URI malformed");
           }
-          var b = (o1 & 0x3f);
+          var b = o1 & 0x3f;
           if ((o2 < 0x80) || (o2 > 0xbf)) {
             throw new $URIError("URI malformed");
           }
-          var c = (o2 & 0x3f);
-          if ((o3 < 0x80) || (o3 > 0xbf)) {
+          var c = o2 & 0x3f;
+          value = (a << 12) + (b << 6) + c;
+          if ((value < 0x800) || (value > 0xffff)) {
             throw new $URIError("URI malformed");
           }
-          var d = (o3 & 0x3f);
-          value = (a << 18) + (b << 12) + (c << 6) + d;
-          if ((value < 0x10000) || (value > 0x10ffff)) {
+        } else {
+          var o3 = octets[3];
+          if (o0 < 0xf8) {
+            var a = (o0 & 0x07);
+            if ((o1 < 0x80) || (o1 > 0xbf)) {
+              throw new $URIError("URI malformed");
+            }
+            var b = (o1 & 0x3f);
+            if ((o2 < 0x80) || (o2 > 0xbf)) {
+              throw new $URIError("URI malformed");
+            }
+            var c = (o2 & 0x3f);
+            if ((o3 < 0x80) || (o3 > 0xbf)) {
+              throw new $URIError("URI malformed");
+            }
+            var d = (o3 & 0x3f);
+            value = (a << 18) + (b << 12) + (c << 6) + d;
+            if ((value < 0x10000) || (value > 0x10ffff)) {
+              throw new $URIError("URI malformed");
+            }
+          } else {
             throw new $URIError("URI malformed");
           }
+        }
+      }
+    }
+    if (0xD800 <= value && value <= 0xDFFF) {
+      throw new $URIError("URI malformed");
+    }
+    if (value < 0x10000) {
+      %_TwoByteSeqStringSetChar(result, index++, value);
+    } else {
+      %_TwoByteSeqStringSetChar(result, index++, (value >> 10) + 0xd7c0);
+      %_TwoByteSeqStringSetChar(result, index++, (value & 0x3ff) + 0xdc00);
+    }
+    return index;
+  }
+
+  // ECMA-262, section 15.1.3
+  function Encode(uri, unescape) {
+    var uriLength = uri.length;
+    var array = new InternalArray(uriLength);
+    var index = 0;
+    for (var k = 0; k < uriLength; k++) {
+      var cc1 = uri.charCodeAt(k);
+      if (unescape(cc1)) {
+        array[index++] = cc1;
+      } else {
+        if (cc1 >= 0xDC00 && cc1 <= 0xDFFF) throw new $URIError("URI malformed");
+        if (cc1 < 0xD800 || cc1 > 0xDBFF) {
+          index = URIEncodeSingle(cc1, array, index);
         } else {
-          throw new $URIError("URI malformed");
+          k++;
+          if (k == uriLength) throw new $URIError("URI malformed");
+          var cc2 = uri.charCodeAt(k);
+          if (cc2 < 0xDC00 || cc2 > 0xDFFF) throw new $URIError("URI malformed");
+          index = URIEncodePair(cc1, cc2, array, index);
         }
       }
     }
-  }
-  if (0xD800 <= value && value <= 0xDFFF) {
-    throw new $URIError("URI malformed");
-  }
-  if (value < 0x10000) {
-    if (index < 0 || index >= result.length) {
-      throw new $URIError("Internal error");
-    }
-    %_TwoByteSeqStringSetChar(result, index++, value);
-    return index;
-  } else {
-    if (index < 0 || index >= result.length - 1) {
-      throw new $URIError("Internal error");
-    }
-    %_TwoByteSeqStringSetChar(result, index++, (value >> 10) + 0xd7c0);
-    %_TwoByteSeqStringSetChar(result, index++, (value & 0x3ff) + 0xdc00);
-    return index;
-  }
-}
-
-
-// ECMA-262, section 15.1.3
-function Encode(uri, unescape) {
-  var uriLength = uri.length;
-  var array = new InternalArray(uriLength);
-  var index = 0;
-  for (var k = 0; k < uriLength; k++) {
-    var cc1 = uri.charCodeAt(k);
-    if (unescape(cc1)) {
-      array[index++] = cc1;
-    } else {
-      if (cc1 >= 0xDC00 && cc1 <= 0xDFFF) throw new $URIError("URI malformed");
-      if (cc1 < 0xD800 || cc1 > 0xDBFF) {
-        index = URIEncodeSingle(cc1, array, index);
+
+    var result = %NewString(array.length, NEW_ONE_BYTE_STRING);
+    for (var i = 0; i < array.length; i++) {
+      %_OneByteSeqStringSetChar(result, i, array[i]);
+    }
+    return result;
+  }
+
+  // ECMA-262, section 15.1.3
+  function Decode(uri, reserved) {
+    var uriLength = uri.length;
+    var one_byte = %NewString(uriLength, NEW_ONE_BYTE_STRING);
+    var index = 0;
+    var k = 0;
+
+    // Optimistically assume ascii string.
+    for ( ; k < uriLength; k++) {
+      var code = uri.charCodeAt(k);
+      if (code == 37) {  // '%'
+        if (k + 2 >= uriLength) throw new $URIError("URI malformed");
+        var cc = URIHexCharsToCharCode(uri.charCodeAt(k+1), uri.charCodeAt(k+2));
+        if (cc >> 7) break;  // Assumption wrong, two byte string.
+        if (reserved(cc)) {
+          %_OneByteSeqStringSetChar(one_byte, index++, 37);  // '%'.
+          %_OneByteSeqStringSetChar(one_byte, index++, uri.charCodeAt(k+1));
+          %_OneByteSeqStringSetChar(one_byte, index++, uri.charCodeAt(k+2));
+        } else {
+          %_OneByteSeqStringSetChar(one_byte, index++, cc);
+        }
+        k += 2;
       } else {
-        k++;
-        if (k == uriLength) throw new $URIError("URI malformed");
-        var cc2 = uri.charCodeAt(k);
-        if (cc2 < 0xDC00 || cc2 > 0xDFFF) throw new $URIError("URI malformed");
-        index = URIEncodePair(cc1, cc2, array, index);
+        if (code > 0x7f) break;  // Assumption wrong, two byte string.
+        %_OneByteSeqStringSetChar(one_byte, index++, code);
       }
     }
-  }
-
-  var result = %NewString(array.length, NEW_ONE_BYTE_STRING);
-  for (var i = 0; i < array.length; i++) {
-    %_OneByteSeqStringSetChar(result, i, array[i]);
-  }
-  return result;
-}
-
-
-// ECMA-262, section 15.1.3
-function Decode(uri, reserved) {
-  var uriLength = uri.length;
-  var one_byte = %NewString(uriLength, NEW_ONE_BYTE_STRING);
-  var index = 0;
-  var k = 0;
-
-  // Optimistically assume ascii string.
-  for ( ; k < uriLength; k++) {
-    var code = uri.charCodeAt(k);
-    if (code == 37) {  // '%'
-      if (k + 2 >= uriLength) throw new $URIError("URI malformed");
-      var cc = URIHexCharsToCharCode(uri.charCodeAt(k+1), uri.charCodeAt(k+2));
-      if (cc >> 7) break;  // Assumption wrong, two byte string.
-      if (reserved(cc)) {
-        %_OneByteSeqStringSetChar(one_byte, index++, 37);  // '%'.
-        %_OneByteSeqStringSetChar(one_byte, index++, uri.charCodeAt(k+1));
-        %_OneByteSeqStringSetChar(one_byte, index++, uri.charCodeAt(k+2));
+
+    one_byte = %TruncateString(one_byte, index);
+    if (k == uriLength) return one_byte;
+
+    // Write into two byte string.
+    var two_byte = %NewString(uriLength - k, NEW_TWO_BYTE_STRING);
+    index = 0;
+
+    for ( ; k < uriLength; k++) {
+      var code = uri.charCodeAt(k);
+      if (code == 37) {  // '%'
+        if (k + 2 >= uriLength) throw new $URIError("URI malformed");
+        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.charCodeAt(++k),
+                                              uri.charCodeAt(++k));
+          }
+          index = URIDecodeOctets(octets, two_byte, index);
+        } else  if (reserved(cc)) {
+          %_TwoByteSeqStringSetChar(two_byte, index++, 37);  // '%'.
+          %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k - 1));
+          %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k));
+        } else {
+          %_TwoByteSeqStringSetChar(two_byte, index++, cc);
+        }
       } else {
-        %_OneByteSeqStringSetChar(one_byte, index++, cc);
+        %_TwoByteSeqStringSetChar(two_byte, index++, code);
       }
-      k += 2;
-    } else {
-      if (code > 0x7f) break;  // Assumption wrong, two byte string.
-      %_OneByteSeqStringSetChar(one_byte, index++, code);
-    }
-  }
-
-  one_byte = %TruncateString(one_byte, index);
-  if (k == uriLength) return one_byte;
-
-  // Write into two byte string.
-  var two_byte = %NewString(uriLength - k, NEW_TWO_BYTE_STRING);
-  index = 0;
-
-  for ( ; k < uriLength; k++) {
-    var code = uri.charCodeAt(k);
-    if (code == 37) {  // '%'
-      if (k + 2 >= uriLength) throw new $URIError("URI malformed");
-      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 $URIError("URI malformed");
-          octets[i] = URIHexCharsToCharCode(uri.charCodeAt(++k),
-                                            uri.charCodeAt(++k));
-        }
-        index = URIDecodeOctets(octets, two_byte, index);
-      } else  if (reserved(cc)) {
-        %_TwoByteSeqStringSetChar(two_byte, index++, 37);  // '%'.
-        %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k - 1));
-        %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k));
-      } else {
-        %_TwoByteSeqStringSetChar(two_byte, index++, cc);
-      }
-    } else {
-      %_TwoByteSeqStringSetChar(two_byte, index++, code);
-    }
-  }
-
-  two_byte = %TruncateString(two_byte, index);
-  return one_byte + two_byte;
-}
-
-
-// ECMA-262 - 15.1.3.1.
-function URIDecode(uri) {
-  var reservedPredicate = function(cc) {
-    // #$
-    if (35 <= cc && cc <= 36) return true;
-    // &
-    if (cc == 38) return true;
-    // +,
-    if (43 <= cc && cc <= 44) return true;
-    // /
-    if (cc == 47) return true;
-    // :;
-    if (58 <= cc && cc <= 59) return true;
-    // =
-    if (cc == 61) return true;
-    // ?@
-    if (63 <= cc && cc <= 64) return true;
-
-    return false;
-  };
-  var string = ToString(uri);
-  return Decode(string, reservedPredicate);
-}
-
-
-// ECMA-262 - 15.1.3.2.
-function URIDecodeComponent(component) {
-  var reservedPredicate = function(cc) { return false; };
-  var string = ToString(component);
-  return Decode(string, reservedPredicate);
-}
-
-
-// Does the char code correspond to an alpha-numeric char.
-function isAlphaNumeric(cc) {
-  // a - z
-  if (97 <= cc && cc <= 122) return true;
-  // A - Z
-  if (65 <= cc && cc <= 90) return true;
-  // 0 - 9
-  if (48 <= cc && cc <= 57) return true;
-
-  return false;
-}
-
-
-// ECMA-262 - 15.1.3.3.
-function URIEncode(uri) {
-  var unescapePredicate = function(cc) {
-    if (isAlphaNumeric(cc)) return true;
-    // !
-    if (cc == 33) return true;
-    // #$
-    if (35 <= cc && cc <= 36) return true;
-    // &'()*+,-./
-    if (38 <= cc && cc <= 47) return true;
-    // :;
-    if (58 <= cc && cc <= 59) return true;
-    // =
-    if (cc == 61) return true;
-    // ?@
-    if (63 <= cc && cc <= 64) return true;
-    // _
-    if (cc == 95) return true;
-    // ~
-    if (cc == 126) return true;
-
-    return false;
-  };
-
-  var string = ToString(uri);
-  return Encode(string, unescapePredicate);
-}
-
-
-// ECMA-262 - 15.1.3.4
-function URIEncodeComponent(component) {
-  var unescapePredicate = function(cc) {
-    if (isAlphaNumeric(cc)) return true;
-    // !
-    if (cc == 33) return true;
-    // '()*
-    if (39 <= cc && cc <= 42) return true;
-    // -.
-    if (45 <= cc && cc <= 46) return true;
-    // _
-    if (cc == 95) return true;
-    // ~
-    if (cc == 126) return true;
-
-    return false;
-  };
-
-  var string = ToString(component);
-  return Encode(string, unescapePredicate);
-}
-
-
-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;
-}
-
-
-// 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 {
+    }
+
+    two_byte = %TruncateString(two_byte, index);
+    return one_byte + two_byte;
+  }
+
+  // -------------------------------------------------------------------
+  // Define exported functions.
+
+  // ECMA-262 - B.2.1.
+  function URIEscapeJS(str) {
+    var s = ToString(str);
+    return %URIEscape(s);
+  }
+
+  // ECMA-262 - B.2.2.
+  function URIUnescapeJS(str) {
+    var s = ToString(str);
+    return %URIUnescape(s);
+  }
+
+  // ECMA-262 - 15.1.3.1.
+  function URIDecode(uri) {
+    var reservedPredicate = function(cc) {
+      // #$
+      if (35 <= cc && cc <= 36) return true;
+      // &
+      if (cc == 38) return true;
+      // +,
+      if (43 <= cc && cc <= 44) return true;
+      // /
+      if (cc == 47) return true;
+      // :;
+      if (58 <= cc && cc <= 59) return true;
+      // =
+      if (cc == 61) return true;
+      // ?@
+      if (63 <= cc && cc <= 64) return true;
+
       return false;
-    }
-  }
-  return true;
-}
-
-
-// ECMA-262 - B.2.1.
-function URIEscapeJS(str) {
-  var s = ToString(str);
-  return %URIEscape(s);
-}
-
-
-// ECMA-262 - B.2.2.
-function URIUnescapeJS(str) {
-  var s = ToString(str);
-  return %URIUnescape(s);
-}
-
-
-// -------------------------------------------------------------------
-
-function SetUpUri() {
+    };
+    var string = ToString(uri);
+    return Decode(string, reservedPredicate);
+  }
+
+  // ECMA-262 - 15.1.3.2.
+  function URIDecodeComponent(component) {
+    var reservedPredicate = function(cc) { return false; };
+    var string = ToString(component);
+    return Decode(string, reservedPredicate);
+  }
+
+  // ECMA-262 - 15.1.3.3.
+  function URIEncode(uri) {
+    var unescapePredicate = function(cc) {
+      if (isAlphaNumeric(cc)) return true;
+      // !
+      if (cc == 33) return true;
+      // #$
+      if (35 <= cc && cc <= 36) return true;
+      // &'()*+,-./
+      if (38 <= cc && cc <= 47) return true;
+      // :;
+      if (58 <= cc && cc <= 59) return true;
+      // =
+      if (cc == 61) return true;
+      // ?@
+      if (63 <= cc && cc <= 64) return true;
+      // _
+      if (cc == 95) return true;
+      // ~
+      if (cc == 126) return true;
+
+      return false;
+    };
+    var string = ToString(uri);
+    return Encode(string, unescapePredicate);
+  }
+
+  // ECMA-262 - 15.1.3.4
+  function URIEncodeComponent(component) {
+    var unescapePredicate = function(cc) {
+      if (isAlphaNumeric(cc)) return true;
+      // !
+      if (cc == 33) return true;
+      // '()*
+      if (39 <= cc && cc <= 42) return true;
+      // -.
+      if (45 <= cc && cc <= 46) return true;
+      // _
+      if (cc == 95) return true;
+      // ~
+      if (cc == 126) return true;
+
+      return false;
+    };
+    var string = ToString(component);
+    return Encode(string, unescapePredicate);
+  }
+
+  // -------------------------------------------------------------------
+  // Install exported functions.
+
   %CheckIsBootstrapping();
 
   // Set up non-enumerable URI functions on the global object and set
   // their names.
   InstallFunctions(global, DONT_ENUM, $Array(
-    "escape", URIEscapeJS,
-    "unescape", URIUnescapeJS,
-    "decodeURI", URIDecode,
-    "decodeURIComponent", URIDecodeComponent,
-    "encodeURI", URIEncode,
-    "encodeURIComponent", URIEncodeComponent
+      "escape", URIEscapeJS,
+      "unescape", URIUnescapeJS,
+      "decodeURI", URIDecode,
+      "decodeURIComponent", URIDecodeComponent,
+      "encodeURI", URIEncode,
+      "encodeURIComponent", URIEncodeComponent
   ));
-}
-
-SetUpUri();
+
+})();