<?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

 */

/**

 * Class to validate and to work with IPv6 addresses.

 *

 * @package SimplePie

 * @subpackage HTTP

 * @copyright 2003-2005 The PHP Group

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

 * @link http://pear.php.net/package/Net_IPv6

 * @author Alexander Merz <alexander.merz@web.de>

 * @author elfrink at introweb dot nl

 * @author Josh Peck <jmp at joshpeck dot org>

 * @author Sam Sneddon <geoffers@gmail.com>

 */

class SimplePie_Net_IPv6

{

	/**

	 * Uncompresses an IPv6 address

	 *

	 * RFC 4291 allows you to compress concecutive zero pieces in an address to

	 * '::'. This method expects a valid IPv6 address and expands the '::' to

	 * the required number of zero pieces.

	 *

	 * Example:  FF01::101   ->  FF01:0:0:0:0:0:0:101

	 *           ::1         ->  0:0:0:0:0:0:0:1

	 *

	 * @author Alexander Merz <alexander.merz@web.de>

	 * @author elfrink at introweb dot nl

	 * @author Josh Peck <jmp at joshpeck dot org>

	 * @copyright 2003-2005 The PHP Group

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

	 * @param string $ip An IPv6 address

	 * @return string The uncompressed IPv6 address

	 */

	public static function uncompress($ip)

	{

		$c1 = -1;

		$c2 = -1;

		if (substr_count($ip, '::') === 1)

		{

			list($ip1, $ip2) = explode('::', $ip);

			if ($ip1 === '')

			{

				$c1 = -1;

			}

			else

			{

				$c1 = substr_count($ip1, ':');

			}

			if ($ip2 === '')

			{

				$c2 = -1;

			}

			else

			{

				$c2 = substr_count($ip2, ':');

			}

			if (strpos($ip2, '.') !== false)

			{

				$c2++;

			}

			// ::

			if ($c1 === -1 && $c2 === -1)

			{

				$ip = '0:0:0:0:0:0:0:0';

			}

			// ::xxx

			else if ($c1 === -1)

			{

				$fill = str_repeat('0:', 7 - $c2);

				$ip = str_replace('::', $fill, $ip);

			}

			// xxx::

			else if ($c2 === -1)

			{

				$fill = str_repeat(':0', 7 - $c1);

				$ip = str_replace('::', $fill, $ip);

			}

			// xxx::xxx

			else

			{

				$fill = ':' . str_repeat('0:', 6 - $c2 - $c1);

				$ip = str_replace('::', $fill, $ip);

			}

		}

		return $ip;

	}

	/**

	 * Compresses an IPv6 address

	 *

	 * RFC 4291 allows you to compress concecutive zero pieces in an address to

	 * '::'. This method expects a valid IPv6 address and compresses consecutive

	 * zero pieces to '::'.

	 *

	 * Example:  FF01:0:0:0:0:0:0:101   ->  FF01::101

	 *           0:0:0:0:0:0:0:1        ->  ::1

	 *

	 * @see uncompress()

	 * @param string $ip An IPv6 address

	 * @return string The compressed IPv6 address

	 */

	public static function compress($ip)

	{

		// Prepare the IP to be compressed

		$ip = self::uncompress($ip);

		$ip_parts = self::split_v6_v4($ip);

		// Replace all leading zeros

		$ip_parts[0] = preg_replace('/(^|:)0+([0-9])/', '\1\2', $ip_parts[0]);

		// Find bunches of zeros

		if (preg_match_all('/(?:^|:)(?:0(?::|$))+/', $ip_parts[0], $matches, PREG_OFFSET_CAPTURE))

		{

			$max = 0;

			$pos = null;

			foreach ($matches[0] as $match)

			{

				if (strlen($match[0]) > $max)

				{

					$max = strlen($match[0]);

					$pos = $match[1];

				}

			}

			$ip_parts[0] = substr_replace($ip_parts[0], '::', $pos, $max);

		}

		if ($ip_parts[1] !== '')

		{

			return implode(':', $ip_parts);

		}

		return $ip_parts[0];

	}

	/**

	 * Splits an IPv6 address into the IPv6 and IPv4 representation parts

	 *

	 * RFC 4291 allows you to represent the last two parts of an IPv6 address

	 * using the standard IPv4 representation

	 *

	 * Example:  0:0:0:0:0:0:13.1.68.3

	 *           0:0:0:0:0:FFFF:129.144.52.38

	 *

	 * @param string $ip An IPv6 address

	 * @return array [0] contains the IPv6 represented part, and [1] the IPv4 represented part

	 */

	private static function split_v6_v4($ip)

	{

		if (strpos($ip, '.') !== false)

		{

			$pos = strrpos($ip, ':');

			$ipv6_part = substr($ip, 0, $pos);

			$ipv4_part = substr($ip, $pos + 1);

			return array($ipv6_part, $ipv4_part);

		}

		return array($ip, '');

	}

	/**

	 * Checks an IPv6 address

	 *

	 * Checks if the given IP is a valid IPv6 address

	 *

	 * @param string $ip An IPv6 address

	 * @return bool true if $ip is a valid IPv6 address

	 */

	public static function check_ipv6($ip)

	{

		$ip = self::uncompress($ip);

		list($ipv6, $ipv4) = self::split_v6_v4($ip);

		$ipv6 = explode(':', $ipv6);

		$ipv4 = explode('.', $ipv4);

		if (count($ipv6) === 8 && count($ipv4) === 1 || count($ipv6) === 6 && count($ipv4) === 4)

		{

			foreach ($ipv6 as $ipv6_part)

			{

				// The section can't be empty

				if ($ipv6_part === '')

					return false;

				// Nor can it be over four characters

				if (strlen($ipv6_part) > 4)

					return false;

				// Remove leading zeros (this is safe because of the above)

				$ipv6_part = ltrim($ipv6_part, '0');

				if ($ipv6_part === '')

					$ipv6_part = '0';

				// Check the value is valid

				$value = hexdec($ipv6_part);

				if (dechex($value) !== strtolower($ipv6_part) || $value < 0 || $value > 0xFFFF)

					return false;

			}

			if (count($ipv4) === 4)

			{

				foreach ($ipv4 as $ipv4_part)

				{

					$value = (int) $ipv4_part;

					if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF)

						return false;

				}

			}

			return true;

		}

		return false;

	}

	/**

	 * Checks if the given IP is a valid IPv6 address

	 *

	 * @codeCoverageIgnore

	 * @deprecated Use {@see SimplePie_Net_IPv6::check_ipv6()} instead

	 * @see check_ipv6

	 * @param string $ip An IPv6 address

	 * @return bool true if $ip is a valid IPv6 address

	 */

	public static function checkIPv6($ip)

	{

		return self::check_ipv6($ip);

	}

}