// HTMLParser Library $Name: v1_6 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2004 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/sax/Locator.java,v $
// $Author: derrickoswald $
// $Date: 2004/07/14 01:58:02 $
// $Revision: 1.1 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//

package org.htmlparser.sax;

import org.htmlparser.Parser;
import org.htmlparser.lexer.Lexer;

/**
 * Transforms character offsets into line and column in the HTML file.
 */
public class Locator
    implements
        org.xml.sax.Locator
{
    /**
     * Underlying parser object.
     */
    protected Parser mParser;

    /**
     * Creates a locator for the given parser.
     * @param parser The parser with the {@link org.htmlparser.lexer.Page Page} being accessed.
     */
    public Locator (Parser parser)
    {
        mParser = parser;
    }
    
    /**
     * Return the public identifier for the current document event.
     *
     * <p>The return value is the public identifier of the document
     * entity or of the external parsed entity in which the markup
     * triggering the event appears.</p>
     *
     * @return A string containing the public identifier, or
     *         null if none is available.
     * @see #getSystemId
     */
    public String getPublicId ()
    {
        return (null); // I assume this would be <title></title>
    }
    
    
    /**
     * Return the system identifier for the current document event.
     *
     * <p>The return value is the system identifier of the document
     * entity or of the external parsed entity in which the markup
     * triggering the event appears.</p>
     *
     * <p>If the system identifier is a URL, the parser must resolve it
     * fully before passing it to the application.  For example, a file
     * name must always be provided as a <em>file:...</em> URL, and other
     * kinds of relative URI are also resolved against their bases.</p>
     *
     * @return A string containing the system identifier, or null
     *         if none is available.
     * @see #getPublicId
     */
    public String getSystemId ()
    {
        return (mParser.getURL ());
    }
    
    
    /**
     * Return the line number where the current document event ends.
     * Lines are delimited by line ends, which are defined in
     * the XML specification.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of diagnostics;
     * it is not intended to provide sufficient information
     * to edit the character content of the original XML document.
     * In some cases, these "line" numbers match what would be displayed
     * as columns, and in others they may not match the source text
     * due to internal entity expansion.  </p>
     *
     * <p>The return value is an approximation of the line number
     * in the document entity or external parsed entity where the
     * markup triggering the event appears.</p>
     *
     * <p>If possible, the SAX driver should provide the line position 
     * of the first character after the text associated with the document 
     * event.  The first line is line 1.</p>
     *
     * @return The line number, or -1 if none is available.
     * @see #getColumnNumber
     */
    public int getLineNumber ()
    {
        Lexer lexer;
        
        lexer = mParser.getLexer ();
        return (lexer.getPage ().row (lexer.getCursor ()));
    }
    
    
    /**
     * Return the column number where the current document event ends.
     * This is one-based number of Java <code>char</code> values since
     * the last line end.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of diagnostics;
     * it is not intended to provide sufficient information
     * to edit the character content of the original XML document.
     * For example, when lines contain combining character sequences, wide
     * characters, surrogate pairs, or bi-directional text, the value may
     * not correspond to the column in a text editor's display. </p>
     *
     * <p>The return value is an approximation of the column number
     * in the document entity or external parsed entity where the
     * markup triggering the event appears.</p>
     *
     * <p>If possible, the SAX driver should provide the line position 
     * of the first character after the text associated with the document 
     * event.  The first column in each line is column 1.</p>
     *
     * @return The column number, or -1 if none is available.
     * @see #getLineNumber
     */
    public int getColumnNumber ()
    {
        Lexer lexer;
        
        lexer = mParser.getLexer ();
        return (lexer.getPage ().column (lexer.getCursor ()));
    }
}
