<?php

/**

 * SimplePie

 *

 * A PHP-Based RSS and Atom Feed Framework.

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

 *

 * Copyright (c) 2004-2022, 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

 */

namespace SimplePie\Net;

/**

 * 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 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) {

            [$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

            elseif ($c1 === -1) {

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

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

            }

            // xxx::

            elseif ($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 [$ipv6_part, $ipv4_part];

        }

        return [$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);

        [$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 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);

    }

}

class_alias('SimplePie\Net\IPv6', 'SimplePie_Net_IPv6');