symon/src/main/java/com/loomcom/symon/jterminal/vt100/AnsiControlSequenceParser.java

/*
 * Copyright (c) 2009-2011 Graham Edgecombe.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package com.loomcom.symon.jterminal.vt100;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

/**
 * A class which parses {@link AnsiControlSequence}s from {@link String}(s).
 * @author Graham Edgecombe
 */
public class AnsiControlSequenceParser {

	/**
	 * The multi-byte control sequence introducer.
	 */
	private static final char[] MULTI_CSI = new char[] { 27, '[' };

	/**
	 * The single-byte control sequence introducer.
	 */
	private static final char SINGLE_CSI = 155;

	/**
	 * The buffer of data from the last call to {@link #parse()}. This is
	 * populated with data if an escape sequence is not complete.
	 */
	private StringBuilder buffer = new StringBuilder();

	/**
	 * The ANSI control sequence listener.
	 */
	private final AnsiControlSequenceListener listener;

	/**
	 * Creates the ANSI control sequence parser.
	 * @param listener The listener.
	 */
	public AnsiControlSequenceParser(AnsiControlSequenceListener listener) {
		this.listener = listener;
	}

	/**
	 * Parses the specified string.
	 * @param str The string to parse.
	 */
	public void parse(String str) {
		if (buffer.length() > 0) {
			str = buffer.toString().concat(str);
			buffer = new StringBuilder();
		}
		Reader reader = new StringReader(str);
		try {
			try {
				parse(reader);
			} finally {
				reader.close();
			}
		} catch (IOException ex) {
			/* ignore */
		}
	}

	/**
	 * Parses characters from the specified character reader.
	 * @param reader The character reader.
	 * @throws IOException if an I/O error occurs.
	 */
	private void parse(Reader reader) throws IOException {
		StringBuilder text = new StringBuilder();
		int character;
		while ((character = reader.read()) != -1) {
			boolean introducedControlSequence = false;
			if (character == SINGLE_CSI) {
				introducedControlSequence = true;
			} else if (character == MULTI_CSI[0]) {
				int nextCharacter = reader.read();
				if (nextCharacter == -1) {
					buffer.append((char) character);
					break;
				} else if (nextCharacter == MULTI_CSI[1]) {
					introducedControlSequence = true;
				} else {
					text.append((char) character);
					text.append((char) nextCharacter);
				}
			} else {
				text.append((char) character);
			}

			if (introducedControlSequence) {
				if (text.length() > 0) {
					listener.parsedString(text.toString());
					text = new StringBuilder();
				}
				parseControlSequence(reader);
			}
		}

		if (text.length() > 0) {
			listener.parsedString(text.toString());
		}
	}

	/**
	 * Parses a control sequence.
	 * @param reader The character reader.
	 * @throws IOException if an I/O error occurs.
	 */
	private void parseControlSequence(Reader reader) throws IOException {
		boolean finishedSequence = false;
		StringBuilder parameters = new StringBuilder();
		int character;
		while ((character = reader.read()) != -1) {
			if ((character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z')) {
				String[] array = parameters.toString().split(";");
				AnsiControlSequence seq = new AnsiControlSequence((char) character, array);
				listener.parsedControlSequence(seq);

				finishedSequence = true;
				break;
			} else {
				parameters.append((char) character);
			}
		}
		if (!finishedSequence) {
			// not an ideal solution if they used the two byte CSI, but it's
			// easier and cleaner than keeping track of it
			buffer.append((char) SINGLE_CSI);
			buffer.append(parameters);
		}
	}

}