// $Header: /home/cvs/jakarta-jmeter/src/htmlparser/org/htmlparser/parserHelper/StringParser.java,v 1.2 2004/02/10 13:41:08 woolfel Exp $
/*
 * ====================================================================
 * Copyright 2002-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

// The developers of JMeter and Apache are greatful to the developers
// of HTMLParser for giving Apache Software Foundation a non-exclusive
// license. The performance benefits of HTMLParser are clear and the
// users of JMeter will benefit from the hard work the HTMLParser
// team. For detailed information about HTMLParser, the project is
// hosted on sourceforge at http://htmlparser.sourceforge.net/.
//
// HTMLParser was originally created by Somik Raha in 2000. Since then
// a healthy community of users has formed and helped refine the
// design so that it is able to tackle the difficult task of parsing
// dirty HTML. Derrick Oswald is the current lead developer and was kind
// enough to assist JMeter.

package org.htmlparser.parserHelper;

import org.htmlparser.Node;
import org.htmlparser.NodeReader;
import org.htmlparser.StringNode;

public class StringParser
{
    private final static int BEFORE_PARSE_BEGINS_STATE = 0;
    private final static int PARSE_HAS_BEGUN_STATE = 1;
    private final static int PARSE_COMPLETED_STATE = 2;
    private final static int PARSE_IGNORE_STATE = 3;

    /**
     * Returns true if the text at pos in line should be scanned as a tag.
     * Basically an open angle followed by a known special character or a letter.
     * @param line The current line being parsed.
     * @param pos The position in the line to examine.
     * @return true if we think this is the start of a tag.
     */
    private boolean beginTag(String line, int pos)
    {
        char ch;
        boolean ret;

        ret = false;

        if (pos + 2 <= line.length())
            if ('<' == line.charAt(pos))
            {
                ch = line.charAt(pos + 1);
                // the order of these tests might be optimized for speed
                if ('/' == ch
                    || '%' == ch
                    || Character.isLetter(ch)
                    || '!' == ch)
                    ret = true;
            }

        return (ret);
    }

    /**
     * Locate the StringNode within the input string, by parsing from the given position
     * @param reader HTML reader to be provided so as to allow reading of next line
     * @param input Input String
     * @param position Position to start parsing from
     * @param balance_quotes If true enter ignoring state on
     * encountering quotes.
     */
    public Node find(
        NodeReader reader,
        String input,
        int position,
        boolean balance_quotes)
    {
        StringBuffer textBuffer = new StringBuffer();
        int state = BEFORE_PARSE_BEGINS_STATE;
        int textBegin = position;
        int textEnd = position;
        int inputLen = input.length();
        char ch;
        char ignore_ender = '\"';
        for (int i = position;
            (i < inputLen && state != PARSE_COMPLETED_STATE);
            i++)
        {
            ch = input.charAt(i);
            if (ch == '<' && state != PARSE_IGNORE_STATE)
            {
                if (beginTag(input, i))
                {
                    state = PARSE_COMPLETED_STATE;
                    textEnd = i - 1;
                }
            }
            if (balance_quotes && (ch == '\'' || ch == '"'))
            {
                if (state == PARSE_IGNORE_STATE)
                {
                    if (ch == ignore_ender)
                        state = PARSE_HAS_BEGUN_STATE;
                }
                else
                {
                    ignore_ender = ch;
                    state = PARSE_IGNORE_STATE;
                }
            }
            if (state == BEFORE_PARSE_BEGINS_STATE)
            {
                state = PARSE_HAS_BEGUN_STATE;
            }
            if (state == PARSE_HAS_BEGUN_STATE || state == PARSE_IGNORE_STATE)
            {
                textBuffer.append(input.charAt(i));
            }
            // Patch by Cedric Rosa
            if (state == BEFORE_PARSE_BEGINS_STATE && i == inputLen - 1)
                state = PARSE_HAS_BEGUN_STATE;
            if (state == PARSE_HAS_BEGUN_STATE && i == inputLen - 1)
            {
                do
                {
                    input = reader.getNextLine();
                    if (input != null && input.length() == 0)
                        textBuffer.append(Node.getLineSeparator());
                }
                while (input != null && input.length() == 0);

                if (input == null)
                {
                    textEnd = i;
                    state = PARSE_COMPLETED_STATE;

                }
                else
                {
                    textBuffer.append(Node.getLineSeparator());
                    inputLen = input.length();
                    i = -1;
                }

            }
        }
        return new StringNode(textBuffer, textBegin, textEnd);
    }
}