<?php
/**
 * A TestUnitKeyProducer iterator
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub 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 TestUnitKeyProducerIterator extends BaseIterator implements Iterator {
	/**
	 * Maximum different bit combinations
	 */
	private $maxBits = 0;

	/**
	 * Key length
	 */
	private $keyLength = 0;

	/**
	 * Current iteration
	 */
	private $currentIteration = 0;

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);

		// Get key length
		$this->keyLength = $this->getConfigInstance()->getConfigEntry('test_unit_random_secret_key_length');

		// Make sure the key length isn't getting to big (32 byte = 256 bit is really, really a lot!)
		assert($this->keyLength <= (8 * 32));

		// Set max bits entry
		$this->maxBits = pow(2, $this->keyLength);

		// Debug message
		$this->debugOutput('ITERATOR: maxBits=' . $this->maxBits . ',keyLength=' . $this->keyLength . ' bits');
	}

	/**
	 * Creates an instance of this class
	 *
	 * @return	$iteratorInstance	An instance of a Iterator class
	 */
	public final static function createTestUnitKeyProducerIterator () {
		// Get new instance
		$iteratorInstance = new TestUnitKeyProducerIterator();

		// Return the prepared instance
		return $iteratorInstance;
	}

	/**
	 * Getter for current value
	 *
	 * @return	$current	Current value in iteration
	 */
	public function current () {
		// Calculate ASCII string representation of the key number
		$current = $this->dec2asc($this->currentIteration);

		// Prepend more zeros
		$current = $this->prependStringToString($current, chr(0), ($this->keyLength / 8));

		// Return it
		return $current;
	}

	/**
	 * Getter for key from group or generic
	 *
	 * @return	$key	Current key in iteration
	 * @throws	UnsupportedOperationException	This method should not be called
	 */
	public function key () {
		throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Advances to the next entry
	 *
	 * @return	void
	 */
	public function next () {
		/*
		 * This is of course a very ineffective key generation iterator because
		 * it will create a lot of keys that will never decode an encrypted
		 * message. If you know a better algorithm which is freely available and
		 * can be implemented as an itertator please contact me.
		 */
		$this->currentIteration++;
	}

	/**
	 * Rewinds to the beginning of the iteration
	 *
	 * @return	void
	 * @throws	UnsupportedOperationException	This method should not be called
	 */
	public function rewind () {
		throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Checks whether the current entry is valid (not at the end of the list)
	 *
	 * @return	void
	 */
	public function valid () {
		return ($this->currentIteration <= $this->maxBits);
	}
}

// [EOF]
?>