1  /*
     2   * Copyright the original author or authors.
     3   * 
     4   * Licensed under the MOZILLA PUBLIC LICENSE, Version 1.1 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   * 
     8   *      http://www.mozilla.org/MPL/MPL-1.1.html
     9   * 
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  import org.as2lib.regexp.node.Node;
    18  
    19  /**
    20   * {@code GroupHead} saves the location where the group begins in the 
    21   * locals and restores them when the match is done.
    22   *
    23   * The matchRef is used when a reference to this group is accessed later
    24   * in the expression. The locals will have a negative value in them to
    25   * indicate that we do not want to unset the group if the reference
    26   * doesn't match.
    27   * 
    28   * @author Igor Sadovskiy
    29   */
    30   
    31  class org.as2lib.regexp.node.GroupHead extends Node {
    32  	
    33      private var localIndex:Number;
    34      
    35      public function GroupHead(localCount:Number) {
    36          localIndex = localCount;
    37      }
    38      
    39      public function match(matcher:Object, i:Number, seq:String):Boolean {
    40          var save:Number = matcher.locals[localIndex];
    41          matcher.locals[localIndex] = i;
    42          var ret:Boolean = next.match(matcher, i, seq);
    43          matcher.locals[localIndex] = save;
    44          return ret;
    45      }
    46      
    47      public function matchRef(matcher:Object, i:Number, seq:String):Boolean {
    48          var save:Number = matcher.locals[localIndex];
    49          matcher.locals[localIndex] = ~i; 
    50          var ret:Boolean = next.match(matcher, i, seq);
    51          matcher.locals[localIndex] = save;
    52          return ret;
    53      }
    54      
    55      public function getLocalIndex(Void):Number {
    56      	return localIndex;
    57      }
    58  }
    59  
    60
as2api