001/*
002 * Copyright (C) 2012 eXo Platform SAS.
003 *
004 * This is free software; you can redistribute it and/or modify it
005 * under the terms of the GNU Lesser General Public License as
006 * published by the Free Software Foundation; either version 2.1 of
007 * the License, or (at your option) any later version.
008 *
009 * This software is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * You should have received a copy of the GNU Lesser General Public
015 * License along with this software; if not, write to the Free
016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018 */
019
020package org.crsh.lang.script;
021
022import org.crsh.command.ScriptException;
023
024class Tokenizer {
025
026  /** . */
027  private final CharSequence s;
028
029  /** . */
030  private int index;
031
032  /** . */
033  private Character c;
034
035  /**
036   * Create a new tokenizer.
037   *
038   * @param s the sequence to tokenize
039   * @throws NullPointerException if the sequence is null
040   */
041  public Tokenizer(CharSequence s) throws NullPointerException {
042    if (s == null) {
043      throw new NullPointerException();
044    }
045    this.s = s;
046    this.index = 0;
047
048    // Initialize state
049    // index points to next char to read
050    // c = s.charAt(index - 1);
051    this.c = index < s.length() ? s.charAt(index++) : null;
052  }
053
054  private void next() {
055    if (index < s.length()) {
056      c = s.charAt(index++);
057    } else {
058      c = null;
059    }
060  }
061
062  public Token nextToken() {
063    if (c == null) {
064      return Token.EOF;
065    } else {
066      switch (c) {
067        case '|':
068          next();
069          return Token.PIPE;
070        default:
071          return parseCommand();
072      }
073    }
074  }
075
076  private Token parseCommand() throws ScriptException {
077
078    //
079    StringBuilder line = new StringBuilder();
080
081    //
082    Character lastQuote = null;
083    while (c != null) {
084      if (lastQuote == null && (c == '+' || c == '|')) {
085        break;
086      } else {
087        line.append(c);
088        switch (c) {
089          case '"':
090          case '\'':
091            if (lastQuote == null) {
092              lastQuote = c;
093            } else if (lastQuote != c) {
094            } else {
095              lastQuote = null;
096            }
097            break;
098          default:
099            break;
100        }
101      }
102
103      //
104      next();
105    }
106
107    //
108    return new Token.Command(line.toString());
109  }
110}