// ========================================================================
// Copyright (c) 1999 Mort Bay Consulting (Australia) Pty. Ltd.
// $Id: QuotedStringTokenizer.java,v 1.1 2001/09/02 01:13:08 gregwilkins Exp $
// ========================================================================

package org.mortbay.util;

import java.util.NoSuchElementException;
import java.util.StringTokenizer;

/* ------------------------------------------------------------ */
/** StringTokenizer with Quoting support.
 *
 * This class is a copy of the java.util.StringTokenizer API and
 * the behaviour is the same, except that single and doulbe quoted
 * string values are recognized.
 * Delimiters within quotes are not considered delimiters.
 * Quotes can be escaped with '\'.
 *
 * @see java.util.StringTokenizer
 * @version $Id: QuotedStringTokenizer.java,v 1.1 2001/09/02 01:13:08 gregwilkins Exp $
 * @author Greg Wilkins (gregw)
 */
public class QuotedStringTokenizer
    extends StringTokenizer
{
    private String _string;
    private String _delim = "\t\n\r";
    private boolean _returnQuotes=false;
    private boolean _returnTokens=false;
    private StringBuffer _token;
    private boolean _hasToken=false;
    private int _i=0;
    private int _lastStart=0;
    
    /* ------------------------------------------------------------ */
    public QuotedStringTokenizer(String str,
                                 String delim,
                                 boolean returnTokens,
                                 boolean returnQuotes)
    {
        super("");
        _string=str;
        if (delim!=null)
            _delim=delim;
        _returnTokens=returnTokens;
        _returnQuotes=returnQuotes;
        
        if (_delim.indexOf('\'')>=0 ||
            _delim.indexOf('"')>=0)
            throw new Error("Can't use quotes as delimiters: "+_delim);
        
        _token=new StringBuffer(_string.length()>1024?512:_string.length()/2);
    }

    /* ------------------------------------------------------------ */
    public QuotedStringTokenizer(String str,
                                 String delim,
                                 boolean returnTokens)
    {
        this(str,delim,returnTokens,false);
    }
    
    /* ------------------------------------------------------------ */
    public QuotedStringTokenizer(String str,
                                 String delim)
    {
        this(str,delim,false,false);
    }

    /* ------------------------------------------------------------ */
    public QuotedStringTokenizer(String str)
    {
        this(str,null,false,false);
    }

    /* ------------------------------------------------------------ */
    public boolean hasMoreTokens()
    {
        // Already found a token
        if (_hasToken)
            return true;
        
        _lastStart=_i;
        
        int state=0;
        boolean escape=false;
        while (_i<_string.length())
        {
            char c=_string.charAt(_i++);
            
            switch (state)
            {
              case 0: // Start
                  if(_delim.indexOf(c)>=0)
                  {
                      if (_returnTokens)
                      {
                          _token.append(c);
                          return _hasToken=true;
                      }
                  }
                  else if (c=='\'')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=2;
                  }
                  else if (c=='\"')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=3;
                  }
                  else
                  {
                      _token.append(c);
                      _hasToken=true;
                      state=1;
                  }
                  continue;
                  
              case 1: // Token
                  _hasToken=true;
                  if(_delim.indexOf(c)>=0)
                  {
                      if (_returnTokens)
                          _i--;
                      return _hasToken;
                  }
                  else if (c=='\'')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=2;
                  }
                  else if (c=='\"')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=3;
                  }
                  else
                      _token.append(c);
                  continue;

                  
              case 2: // Single Quote
                  _hasToken=true;
                  if (escape)
                  {
                      escape=false;
                      _token.append(c);
                  }
                  else if (c=='\'')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=1;
                  }
                  else if (c=='\\')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      escape=true;
                  }
                  else
                      _token.append(c);
                  continue;

                  
              case 3: // Double Quote
                  _hasToken=true;
                  if (escape)
                  {
                      escape=false;
                      _token.append(c);
                  }
                  else if (c=='\"')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      state=1;
                  }
                  else if (c=='\\')
                  {
                      if (_returnQuotes)
                          _token.append(c);
                      escape=true;
                  }
                  else
                      _token.append(c);
                  continue;
            }
        }

        return _hasToken;
    }

    /* ------------------------------------------------------------ */
    public String nextToken()
        throws NoSuchElementException 
    {
        if (!hasMoreTokens() || _token==null)
            throw new NoSuchElementException();
        String t=_token.toString();
        _token.setLength(0);
        _hasToken=false;
        return t;
    }

    /* ------------------------------------------------------------ */
    public String nextToken(String delim)
        throws NoSuchElementException 
    {
        _delim=delim;
        _i=_lastStart;
        _token.setLength(0);
        _hasToken=false;
        return nextToken();
    }

    /* ------------------------------------------------------------ */
    public boolean hasMoreElements()
    {
        return hasMoreTokens();
    }

    /* ------------------------------------------------------------ */
    public Object nextElement()
        throws NoSuchElementException 
    {
        return nextToken();
    }

    /* ------------------------------------------------------------ */
    /** Not implemented.
     */
    public int countTokens()
    {
        return -1;
    }

    
    /* ------------------------------------------------------------ */
    /** Quote a string.
     * The string is quoted only if quoting is required due to
     * embeded delimiters, quote characters or the
     * empty string.
     * @param s The string to quote.
     * @return quoted string
     */
    public static String quote(String s, String delim)
    {
        if (s==null)
            return null;
        if (s.length()==0)
            return "\"\"";
        StringBuffer b=new StringBuffer(s.length()+8);
        boolean quote=false;
        synchronized(b)
        {
            b.append("\"");
            for (int i=0;i<s.length();i++)
            {
                char c = s.charAt(i);
                if (c=='"')
                {   
                      b.append("\\\"");
                      quote=true;
                      continue;
                }
                if (c=='\\')
                {   
                      b.append("\\\\");
                      quote=true;
                      continue;
                }
                if (c=='\'')
                {   
                      b.append('\'');
                      quote=true;
                      continue;
                }
                else if (delim.indexOf(c)>=0)
                {
                    quote=true;
                    b.append(c);
                    continue;
                }
                else
                {
                    b.append(c);
                    continue;
                }
            }
            if (quote)
            {
                b.append("\"");
                return b.toString();
            }
        }
        return s;
    }


    /* ------------------------------------------------------------ */
    /** Unquote a string.
     * @param s The string to unquote.
     * @return quoted string
     */
    public static String unquote(String s)
    {
        if (s==null)
            return null;
        if (s.length()<2)
            return s;

        char first=s.charAt(0);
        char last=s.charAt(s.length()-1);
        if (first!=last || (first!='"' && first!='\''))
            return s;
        
        StringBuffer b=new StringBuffer(s.length()-2);
        synchronized(b)
        {
            boolean quote=false;
            for (int i=1;i<s.length()-1;i++)
            {
                char c = s.charAt(i);

                if (c=='\\' && !quote)
                {
                    quote=true;
                    continue;
                }
                quote=false;
                b.append(c);
            }
            
            return b.toString();
        }
    }
}