Port and integrate the irregexp engine from V8

runtime/lib/regexp_patch.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class RegExp {
   /* patch */ factory RegExp(String source,
                              {bool multiLine: false,
-                              bool caseSensitive: true}) {
-    return new _JSSyntaxRegExp(source,
+                              bool caseSensitive: true}) {    
+    _JSSyntaxRegExpHash hash = new _JSSyntaxRegExpHash(
+        source, multiLine, caseSensitive);
+    if (!_regExpCache.containsKey(hash)) {
+      _regExpCache[hash] = new _JSSyntaxRegExp(source,
                                multiLine: multiLine,
                                caseSensitive: caseSensitive);
+    }
+    
+    return _regExpCache[hash];
+  }
+  
+  static final Map<_JSSyntaxRegExpHash, _JSSyntaxRegExp> _regExpCache =
+      <_JSSyntaxRegExpHash, _JSSyntaxRegExp>{ };
+}
+
+// Represents a key in the regular expression cache.
+class _JSSyntaxRegExpHash {
+  final String pattern;
+  final bool multiLine;
+  final bool caseSensitive;
+  
+  _JSSyntaxRegExpHash(this.pattern, this.multiLine, this.caseSensitive);
+  
+  int get hashCode => pattern.hashCode;
+  bool operator==(_JSSyntaxRegExpHash that) {
+    return (pattern == that.pattern) &&
+           (this.multiLine == that.multiLine) &&
+           (this.caseSensitive == that.caseSensitive);
   }
 }
 
 class _JSRegExpMatch implements Match {
   _JSRegExpMatch(this._regexp, this.input, this._match);
 
   int get start => _start(0);
   int get end => _end(0);
 
   int _start(int groupIdx) {
@@ skipping 89 matching lines @@
   }
 
   String get pattern native "JSSyntaxRegExp_getPattern";
 
   bool get isMultiLine native "JSSyntaxRegExp_getIsMultiLine";
 
   bool get isCaseSensitive native "JSSyntaxRegExp_getIsCaseSensitive";
 
   int get _groupCount native "JSSyntaxRegExp_getGroupCount";
 
+  // Byte map of one byte characters with a 0xff if the character is a word
+  // character (digit, letter or underscore) and 0x00 otherwise.
+  // Used by generated RegExp code.
+  static const List<int> _wordCharacterMap = const <int>[
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // '0' - '7'
+    0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // '8' - '9'
+
+    0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'A' - 'G'
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'H' - 'O'
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'P' - 'W'
+    0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0xff,  // 'X' - 'Z', '_'
+
+    0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'a' - 'g'
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'h' - 'o'
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  // 'p' - 'w'
+    0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00,  // 'x' - 'z'
+    // Latin-1 range
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  ];
+
   List _ExecuteMatch(String str, int start_index)
       native "JSSyntaxRegExp_ExecuteMatch";
 }
 
 class _AllMatchesIterable extends IterableBase<Match> {
   final _JSSyntaxRegExp _re;
   final String _str;
   final int _start;
 
   _AllMatchesIterable(this._re, this._str, this._start);
@@ skipping 23 matching lines @@
           _nextIndex++;
         }
         return true;
       }
     }
     _current = null;
     _re = null;
     return false;
   }
 }