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  import org.as2lib.regexp.node.BnM;
    19  import org.as2lib.regexp.node.TreeInfo;
    20  
    21  /**
    22   * {@code First} searches until the next instance of its atom. This is 
    23   * useful for finding the atom efficiently without passing an instance of it
    24   * (greedy problem) and without a lot of wasted search time (reluctant
    25   * problem).
    26   * 
    27   * @author Igor Sadovskiy
    28   */
    29   
    30  class org.as2lib.regexp.node.First extends Node {
    31  	
    32      private var atom:Node;
    33      
    34      public function First(node:Node) {
    35          this.atom = BnM.optimize(node);
    36      }
    37      
    38      public function match(matcher:Object, i:Number, seq:String):Boolean {
    39          if (atom instanceof BnM) {
    40              return atom.match(matcher, i, seq)
    41                  && next.match(matcher, matcher.last, seq);
    42          }
    43          while (true) {
    44              if (i > matcher.to) {
    45                  return false;
    46              }
    47              if (atom.match(matcher, i, seq)) {
    48                  return next.match(matcher, matcher.last, seq);
    49              }
    50              i++;
    51              matcher.first++;
    52          }
    53      }
    54      
    55      public function study(info:TreeInfo):Boolean {
    56          atom.study(info);
    57          info.maxValid = false;
    58          info.deterministic = false;
    59          return next.study(info);
    60      }
    61  }
    62  
    63
as2api