//==============================================================================
// CommandFile.java
//==============================================================================

package tribble.net.ftp.shell;


// System imports

import java.io.IOException;
import java.io.Reader;
import java.io.PrintWriter;

import java.lang.Exception;
import java.lang.String;


/*******************************************************************************
* FTP source command script.
* Manages the input stream for a single command script.
*
* <!-- - - - - - - - - - - - - - - - - -->
* @version	$Revision: 1.3 $ $Date: 2007/03/27 23:54:44 $
* @since	API 1.0, 2007-03-22
* @author	David R. Tribble (david&#64;tribble.com).
*	<p>
*	Copyright ©2007 by David R. Tribble, all rights reserved.<br>
*	Permission is granted to any person or entity except those designated by
*	by the United States Department of State as a terrorist, or terrorist
*	government or agency, to use and distribute this source code provided
*	that the original copyright notice remains present and unaltered.
*
* @see	CommandLexer
*/

class CommandFile
{
// Identification

    /** Revision information. */
    static final String		REV =
        "@(#)tribble/net/ftp/shell/CommandFile.java $Revision: 1.3 $ $Date: 2007/03/27 23:54:44 $\n";


// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Variables

    /** Source name. */
    private String		m_srcName =	"-";

    /** Previous (outer) command script. */
    private CommandFile		m_prev;

    /** Input source stream. */
    private Reader		m_in;

    /** Error/warning message output stream. */
    private PrintWriter		m_out;

    /** Source line number of the next input character. */
    int				m_lineNo =	1;

    /** Pushed-back character. */
    private int			m_nextChar =	-1;

    /** Last character read. */
    private int			m_lastCh =	-1;


// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Constructors

    /***************************************************************************
    * Constructor.
    *
    * @param	in
    * Input source stream.
    *
    * @param	out
    * Error/warning message output stream.
    *
    * @param	prev
    * Previous source stream that includes this one.
    *
    * @since	1.1, 2007-03-22
    */

    CommandFile(Reader in, PrintWriter out, CommandFile prev)
    {
        m_in =   in;
        m_out =  out;
        m_prev = prev;
    }


// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Methods

    /***************************************************************************
    * Establish the name of this source stream (the command script).
    *
    * @param	name
    * Name of the input stream.  This is usually a filename, but it can be any
    * kind of identification for the source stream.
    *
    * @since	1.1, 2007-03-22
    */

    void setSourceName(String name)
    {
        m_srcName = name;
    }


    /***************************************************************************
    * Retrieve the name of this source stream (the command script).
    *
    * @return
    * Name of the input stream.  This is usually a filename, but it can be any
    * kind of identification for the source stream.
    *
    * @since	1.3, 2007-03-27
    */

    String getSourceName()
    {
        return (m_srcName);
    }


    /***************************************************************************
    * Terminate this input source stream.
    *
    * @return
    * The previous source stream that included this one, or null if this was the
    * first (top-most) source stream.  Note that the input stream itself is
    * <i>not</i> closed.
    *
    * @since	1.1, 2007-03-22
    */

    CommandFile pop()
    {
        // Shut down this source stream
        m_in = null;
        return (m_prev);
    }


    /***************************************************************************
    * Read the next input characters from this input source stream.
    * This also updates {@link #m_lineNo} to reflect the source line number of
    * the returned character.
    *
    * <p>
    * Each newline (end of line) sequence (CR, LF, CR/LF) is translated into a
    * single newline character (<tt>'\n'</tt>).  A newline character
    * (<tt>'\n'</tt>) is always returned as the last character before the
    * end of the input stream, even if the stream does not contain a final
    * newline sequence.
    *
    * @return
    * The next character from the input source stream, or <tt>'\n'</tt> if an
    * end of line (newline) is reached, or -1 if the end of the source stream
    * is reached.  Note that the stream is <i>not</i> closed after the end is
    * reached.
    *
    * @since	1.1, 2007-03-22
    */

    int readChar()
        throws IOException
    {
        int	ch;
        int	prev;

        // Check for a pushed-back character
        if (m_nextChar >= 0)
        {
            ch = m_nextChar;
            m_nextChar = -1;
            return (ch);
        }

        // Check for end of input
        if (m_in == null)
            return (-1);

        // Read the next input character
        ch = m_in.read();

        // Handle end of input
        if (ch < 0)
        {
            if (m_lastCh != '\r'  &&  m_lastCh != '\n')
            {
                // Insert a final newline
                m_out.println(m_srcName + ":" + m_lineNo
                    + ": warning: Missing a newline at end of file");
                m_out.flush();
                m_lastCh = '\n';
                return ('\n');
            }
            else
            {
                m_in = null;
                return (-1);
            }
        }

        // Handle end of line (newline)
        prev = m_lastCh;
        m_lastCh = ch;

        if (ch == '\r')
        {
            m_lineNo++;
            return ('\n');
        }
        else if (ch == '\n')
        {
            if (prev == '\r')
            {
                // Ignore LF of CR/LF pair, read another char
                return (readChar());
            }
            else
            {
                m_lineNo++;
                return ('\n');
            }
        }
        else if (ch == '\t'  ||  ch == '\f')
        {
            return (' ');
        }
        else if (Character.isISOControl((char) ch))
        {
            String	s;

            // Unprintable control character, treat like a space
            s = (ch < 0x10 ? "0" : "") + Integer.toHexString(ch);
            s = s.toUpperCase();
            m_out.println(m_srcName + ":" + m_lineNo
                + ": warning: Unprintable character (0x" + s
                + ") replaced with a space");
            m_out.flush();
            return (' ');
        }
        else
        {
            // Normal character
            return (ch);
        }
    }


    /***************************************************************************
    * Push back an input character from the source script.
    *
    * @see	#readChar readChar()
    *
    * @since	1.1, 2007-03-22
    */

    void unReadChar(int ch)
    {
        m_nextChar = ch;
    }
}

// End CommandFile.java