<?php

/**

 * SimplePie

 *

 * A PHP-Based RSS and Atom Feed Framework.

 * Takes the hard work out of managing a complete RSS/Atom solution.

 *

 * Copyright (c) 2004-2016, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modification, are

 * permitted provided that the following conditions are met:

 *

 * 	* Redistributions of source code must retain the above copyright notice, this list of

 * 	  conditions and the following disclaimer.

 *

 * 	* Redistributions in binary form must reproduce the above copyright notice, this list

 * 	  of conditions and the following disclaimer in the documentation and/or other materials

 * 	  provided with the distribution.

 *

 * 	* Neither the name of the SimplePie Team nor the names of its contributors may be used

 * 	  to endorse or promote products derived from this software without specific prior

 * 	  written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY

 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS

 * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 *

 * @package SimplePie

 * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue

 * @author Ryan Parman

 * @author Sam Sneddon

 * @author Ryan McCue

 * @link http://simplepie.org/ SimplePie

 * @license http://www.opensource.org/licenses/bsd-license.php BSD License

 */

/**

 * Parses the XML Declaration

 *

 * @package SimplePie

 * @subpackage Parsing

 */

class SimplePie_XML_Declaration_Parser

{

	/**

	 * XML Version

	 *

	 * @access public

	 * @var string

	 */

	var $version = '1.0';

	/**

	 * Encoding

	 *

	 * @access public

	 * @var string

	 */

	var $encoding = 'UTF-8';

	/**

	 * Standalone

	 *

	 * @access public

	 * @var bool

	 */

	var $standalone = false;

	/**

	 * Current state of the state machine

	 *

	 * @access private

	 * @var string

	 */

	var $state = 'before_version_name';

	/**

	 * Input data

	 *

	 * @access private

	 * @var string

	 */

	var $data = '';

	/**

	 * Input data length (to avoid calling strlen() everytime this is needed)

	 *

	 * @access private

	 * @var int

	 */

	var $data_length = 0;

	/**

	 * Current position of the pointer

	 *

	 * @var int

	 * @access private

	 */

	var $position = 0;

	/**

	 * Create an instance of the class with the input data

	 *

	 * @access public

	 * @param string $data Input data

	 */

	public function __construct($data)

	{

		$this->data = $data;

		$this->data_length = strlen($this->data);

	}

	/**

	 * Parse the input data

	 *

	 * @access public

	 * @return bool true on success, false on failure

	 */

	public function parse()

	{

		while ($this->state && $this->state !== 'emit' && $this->has_data())

		{

			$state = $this->state;

			$this->$state();

		}

		$this->data = '';

		if ($this->state === 'emit')

		{

			return true;

		}

		$this->version = '';

		$this->encoding = '';

		$this->standalone = '';

		return false;

	}

	/**

	 * Check whether there is data beyond the pointer

	 *

	 * @access private

	 * @return bool true if there is further data, false if not

	 */

	public function has_data()

	{

		return (bool) ($this->position < $this->data_length);

	}

	/**

	 * Advance past any whitespace

	 *

	 * @return int Number of whitespace characters passed

	 */

	public function skip_whitespace()

	{

		$whitespace = strspn($this->data, "\x09\x0A\x0D\x20", $this->position);

		$this->position += $whitespace;

		return $whitespace;

	}

	/**

	 * Read value

	 */

	public function get_value()

	{

		$quote = substr($this->data, $this->position, 1);

		if ($quote === '"' || $quote === "'")

		{

			$this->position++;

			$len = strcspn($this->data, $quote, $this->position);

			if ($this->has_data())

			{

				$value = substr($this->data, $this->position, $len);

				$this->position += $len + 1;

				return $value;

			}

		}

		return false;

	}

	public function before_version_name()

	{

		if ($this->skip_whitespace())

		{

			$this->state = 'version_name';

		}

		else

		{

			$this->state = false;

		}

	}

	public function version_name()

	{

		if (substr($this->data, $this->position, 7) === 'version')

		{

			$this->position += 7;

			$this->skip_whitespace();

			$this->state = 'version_equals';

		}

		else

		{

			$this->state = false;

		}

	}

	public function version_equals()

	{

		if (substr($this->data, $this->position, 1) === '=')

		{

			$this->position++;

			$this->skip_whitespace();

			$this->state = 'version_value';

		}

		else

		{

			$this->state = false;

		}

	}

	public function version_value()

	{

		if ($this->version = $this->get_value())

		{

			$this->skip_whitespace();

			if ($this->has_data())

			{

				$this->state = 'encoding_name';

			}

			else

			{

				$this->state = 'emit';

			}

		}

		else

		{

			$this->state = false;

		}

	}

	public function encoding_name()

	{

		if (substr($this->data, $this->position, 8) === 'encoding')

		{

			$this->position += 8;

			$this->skip_whitespace();

			$this->state = 'encoding_equals';

		}

		else

		{

			$this->state = 'standalone_name';

		}

	}

	public function encoding_equals()

	{

		if (substr($this->data, $this->position, 1) === '=')

		{

			$this->position++;

			$this->skip_whitespace();

			$this->state = 'encoding_value';

		}

		else

		{

			$this->state = false;

		}

	}

	public function encoding_value()

	{

		if ($this->encoding = $this->get_value())

		{

			$this->skip_whitespace();

			if ($this->has_data())

			{

				$this->state = 'standalone_name';

			}

			else

			{

				$this->state = 'emit';

			}

		}

		else

		{

			$this->state = false;

		}

	}

	public function standalone_name()

	{

		if (substr($this->data, $this->position, 10) === 'standalone')

		{

			$this->position += 10;

			$this->skip_whitespace();

			$this->state = 'standalone_equals';

		}

		else

		{

			$this->state = false;

		}

	}

	public function standalone_equals()

	{

		if (substr($this->data, $this->position, 1) === '=')

		{

			$this->position++;

			$this->skip_whitespace();

			$this->state = 'standalone_value';

		}

		else

		{

			$this->state = false;

		}

	}

	public function standalone_value()

	{

		if ($standalone = $this->get_value())

		{

			switch ($standalone)

			{

				case 'yes':

					$this->standalone = true;

					break;

				case 'no':

					$this->standalone = false;

					break;

				default:

					$this->state = false;

					return;

			}

			$this->skip_whitespace();

			if ($this->has_data())

			{

				$this->state = false;

			}

			else

			{

				$this->state = 'emit';

			}

		}

		else

		{

			$this->state = false;

		}

	}

}