<?php
/**
 * A class for handling incoming (encoded) raw data with start and end markers.
 * The "stream" is being verified by its length (if modulo 4 of it is always
 * zero) and if the "stream" contains all valid characters (the BASE64
 * "alphabet").
 *
 * Since the latest refacturing this class works "handler-less".
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009  Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.ship-simu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
class RawDataInputStream extends BaseStream implements InputStreamable {
	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Creates an instance of this node class
	 *
	 * @return	$streamInstance		An instance of this node class
	 */
	public final static function createRawDataInputStream () {
		// Get a new instance
		$streamInstance = new RawDataInputStream();

		// Return the instance
		return $streamInstance;
	}

	/**
	 * Streams the data and maybe does something to it
	 *
	 * @param	$data	The data (string mostly) to "stream"
	 * @return	$data	The data (string mostly) to "stream"
	 * @todo	Do we need to do something more here?
	 * @throws	Base64EncodingModuloException	If the data's length modulo 4 is not zero
	 * @throws	Base64EncodingBadException		If the data contains characters which are not in the "alphabet" of BASE64 messages.
	 */
	public function streamData ($data) {
		// Do we have start and end marker again?
		assert($this->ifStartEndMarkersSet($data));

		// Remove both
		$data = substr($data, strlen(BaseRawDataHandler::STREAM_START_MARKER), -1 * strlen(BaseRawDataHandler::STREAM_END_MARKER));

		// Can it be validated?
		if ((strlen($data) % 4) != 0) {
			// Length modulo 4 must be zero, else it is an invalid Base64 message
			throw new Base64EncodingModuloException(array($this, $data), self::EXCEPTION_BASE64_ENCODING_NOT_MODULO_4);
		} elseif (!$this->isBase64Encoded($data)) {
			// Is not a valid Base64-encoded message
			throw new Base64EncodingBadException(array($this, $data), self::EXCEPTION_BASE64_BAD_ENCODING);
		} else {
			// Decode the data with BASE64-encoding
			$data = base64_decode($data);
		}

		// Debug message
		/* NOISY-DEBUG: */ $this->debugOutput('RAW-INPUT-STREAM: Length of data is now ' . strlen($data) . ' Bytes.');

		// Return it
		return $data;
	}
}

// [EOF]
?>