text: /* ***** BEGIN LICENSE BLOCK *****
   * Distributed under the BSD license:
   *
   * Copyright (c) 2010, Ajax.org B.V.
   * 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 with the distribution.
   *     * Neither the name of Ajax.org B.V. nor the
   *       names of its contributors may be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ***** END LICENSE BLOCK ***** */
  
  define(function(require, exports, module) {
  "use strict";
  
  var Range = require("./range").Range;
  
  /**
   * 
   *
   * This class provides an essay way to treat the document as a stream of tokens, and provides methods to iterate over these tokens.
   * @class TokenIterator
   **/
  
  /**
   * Creates a new token iterator object. The inital token index is set to the provided row and column coordinates.
   * @param {EditSession} session The session to associate with
   * @param {Number} initialRow The row to start the tokenizing at
   * @param {Number} initialColumn The column to start the tokenizing at
   *
   * @constructor
   **/
  var TokenIterator = function(session, initialRow, initialColumn) {
      this.$session = session;
      this.$row = initialRow;
      this.$rowTokens = session.getTokens(initialRow);
  
      var token = session.getTokenAt(initialRow, initialColumn);
      this.$tokenIndex = token ? token.index : -1;
  };
  
  (function() {
     
      /**
       * Tokenizes all the items from the current point to the row prior in the document. 
       * @returns {[String]} If the current point is not at the top of the file, this function returns `null`. Otherwise, it returns an array of the tokenized strings.
       **/ 
      this.stepBackward = function() {
          this.$tokenIndex -= 1;
          
          while (this.$tokenIndex < 0) {
              this.$row -= 1;
              if (this.$row < 0) {
                  this.$row = 0;
                  return null;
              }
                  
              this.$rowTokens = this.$session.getTokens(this.$row);
              this.$tokenIndex = this.$rowTokens.length - 1;
          }
              
          return this.$rowTokens[this.$tokenIndex];
      };
    
      /**
       * Tokenizes all the items from the current point until the next row in the document. If the current point is at the end of the file, this function returns `null`. Otherwise, it returns the tokenized string.
       * @returns {String}
       **/   
      this.stepForward = function() {
          this.$tokenIndex += 1;
          var rowCount;
          while (this.$tokenIndex >= this.$rowTokens.length) {
              this.$row += 1;
              if (!rowCount)
                  rowCount = this.$session.getLength();
              if (this.$row >= rowCount) {
                  this.$row = rowCount - 1;
                  return null;
              }
  
              this.$rowTokens = this.$session.getTokens(this.$row);
              this.$tokenIndex = 0;
          }
              
          return this.$rowTokens[this.$tokenIndex];
      };
   
      /**
       * 
       * Returns the current tokenized string.
       * @returns {String}
       **/      
      this.getCurrentToken = function () {
          return this.$rowTokens[this.$tokenIndex];
      };
  
      /**
       * 
       * Returns the current row.
       * @returns {Number}
       **/      
      this.getCurrentTokenRow = function () {
          return this.$row;
      };
  
      /**
       * 
       * Returns the current column.
       * @returns {Number}
       **/     
      this.getCurrentTokenColumn = function() {
          var rowTokens = this.$rowTokens;
          var tokenIndex = this.$tokenIndex;
          
          // If a column was cached by EditSession.getTokenAt, then use it
          var column = rowTokens[tokenIndex].start;
          if (column !== undefined)
              return column;
              
          column = 0;
          while (tokenIndex > 0) {
              tokenIndex -= 1;
              column += rowTokens[tokenIndex].value.length;
          }
          
          return column;  
      };
  
      /**
       * Return the current token position.
       * @returns {Position}
       */
      this.getCurrentTokenPosition = function() {
          return {row: this.$row, column: this.getCurrentTokenColumn()};
      };
      
      /**
       * Return the current token range.
       * @returns {Range}
       */
      this.getCurrentTokenRange = function() {
          var token = this.$rowTokens[this.$tokenIndex];
          var column = this.getCurrentTokenColumn();
          return new Range(this.$row, column, this.$row, column + token.value.length);
      };
      
  }).call(TokenIterator.prototype);
  
  exports.TokenIterator = TokenIterator;
  });
  