<?php

/**

 * WordPress implementation for PHP functions either missing from older PHP versions or not included by default.

 *

 * @package PHP

 * @access private

 */

// If gettext isn't available.

if ( ! function_exists( '_' ) ) {

	}

}

/**

 * Returns whether PCRE/u (PCRE_UTF8 modifier) is available for use.

 *

 * @ignore

 * @since 4.2.2

 * @access private

 *

 * @param bool $set - Used for testing only

 *             null   : default - get PCRE/u capability

 *             false  : Used for testing - return false for future calls to this function

 *             'reset': Used for testing - restore default behavior of this function

 */

function _wp_can_use_pcre_u( $set = null ) {

	static $utf8_pcre = 'reset';

	if ( null !== $set ) {

		$utf8_pcre = $set;

	}

	if ( 'reset' === $utf8_pcre ) {

		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- intentional error generated to detect PCRE/u support.

		$utf8_pcre = @preg_match( '/^./u', 'a' );

	}

	return $utf8_pcre;

}

if ( ! function_exists( 'mb_substr' ) ) :

	/**

	 * Compat function to mimic mb_substr().

	 *

	 * @ignore

	 * @since 3.2.0

	 *

	 * @see _mb_substr()

	 *

	 *                              Default null.

	 * @param string|null $encoding Optional. Character encoding to use. Default null.

	 * @return string Extracted substring.

	 */

	}

endif;

/**

 * Internal compat function to mimic mb_substr().

 *

 *

 * @ignore

 * @since 3.2.0

 *

 * @param string      $str      The string to extract the substring from.

 * @param int         $start    Position to being extraction from in `$str`.

 * @param int|null    $length   Optional. Maximum number of characters to extract from `$str`.

 *                              Default null.

 * @param string|null $encoding Optional. Character encoding to use. Default null.

 * @return string Extracted substring.

 */

function _mb_substr( $str, $start, $length = null, $encoding = null ) {

	if ( null === $str ) {

		return '';

	}

	if ( null === $encoding ) {

		$encoding = get_option( 'blog_charset' );

	}

	/*

	 * The solution below works only for UTF-8, so in case of a different

	 * charset just use built-in substr().

	 */

		return is_null( $length ) ? substr( $str, $start ) : substr( $str, $start, $length );

	}

	if ( _wp_can_use_pcre_u() ) {

		// Use the regex unicode support to separate the UTF-8 characters into an array.

		preg_match_all( '/./us', $str, $match );

		$chars = is_null( $length ) ? array_slice( $match[0], $start ) : array_slice( $match[0], $start, $length );

		return implode( '', $chars );

	}

	$regex = '/(

		[\x00-\x7F]                  # single-byte sequences   0xxxxxxx

		| [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx

		| \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2

		| [\xE1-\xEC][\x80-\xBF]{2}

		| \xED[\x80-\x9F][\x80-\xBF]

		| [\xEE-\xEF][\x80-\xBF]{2}

		| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3

		| [\xF1-\xF3][\x80-\xBF]{3}

		| \xF4[\x80-\x8F][\x80-\xBF]{2}

	)/x';

	// Start with 1 element instead of 0 since the first thing we do is pop.

	$chars = array( '' );

	do {

		// We had some string left over from the last round, but we counted it in that last round.

		array_pop( $chars );

		/*

		 * Split by UTF-8 character, limit to 1000 characters (last array element will contain

		 * the rest of the string).

		 */

		$pieces = preg_split( $regex, $str, 1000, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );

		$chars = array_merge( $chars, $pieces );

		// If there's anything left over, repeat the loop.

	} while ( count( $pieces ) > 1 && $str = array_pop( $pieces ) );

	return implode( '', array_slice( $chars, $start, $length ) );

}

if ( ! function_exists( 'mb_strlen' ) ) :

	/**

	 * Compat function to mimic mb_strlen().

	 *

	 * @ignore

	 * @since 4.2.0

	 *

	 * @see _mb_strlen()

	 *

	 * @param string|null $encoding Optional. Character encoding to use. Default null.

	 */

	}

endif;

/**

 * Internal compat function to mimic mb_strlen().

 *

 * sequence. The behavior of this function for invalid inputs is undefined.

 *

 * @ignore

 * @since 4.2.0

 *

 * @param string      $str      The string to retrieve the character length from.

 * @param string|null $encoding Optional. Character encoding to use. Default null.

 * @return int String length of `$str`.

 */

function _mb_strlen( $str, $encoding = null ) {

	if ( null === $encoding ) {

		$encoding = get_option( 'blog_charset' );

	}

	/*

	 * The solution below works only for UTF-8, so in case of a different charset

	 * just use built-in strlen().

	 */

		return strlen( $str );

	}

	if ( _wp_can_use_pcre_u() ) {

		// Use the regex unicode support to separate the UTF-8 characters into an array.

		preg_match_all( '/./us', $str, $match );

		return count( $match[0] );

	}

	$regex = '/(?:

		[\x00-\x7F]                  # single-byte sequences   0xxxxxxx

		| [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx

		| \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2

		| [\xE1-\xEC][\x80-\xBF]{2}

		| \xED[\x80-\x9F][\x80-\xBF]

		| [\xEE-\xEF][\x80-\xBF]{2}

		| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3

		| [\xF1-\xF3][\x80-\xBF]{3}

		| \xF4[\x80-\x8F][\x80-\xBF]{2}

	)/x';

	// Start at 1 instead of 0 since the first thing we do is decrement.

	$count = 1;

	do {

		// We had some string left over from the last round, but we counted it in that last round.

		/*

		 * Split by UTF-8 character, limit to 1000 characters (last array element will contain

		 * the rest of the string).

		 */

		$pieces = preg_split( $regex, $str, 1000 );

		// Increment.

		$count += count( $pieces );

		// If there's anything left over, repeat the loop.

	} while ( $str = array_pop( $pieces ) );

	// Fencepost: preg_split() always returns one extra item in the array.

	return --$count;

}

if ( ! function_exists( 'hash_hmac' ) ) :

	/**

	 * Compat function to mimic hash_hmac().

	 *

	 * The Hash extension is bundled with PHP by default since PHP 5.1.2.

	 * However, the extension may be explicitly disabled on select servers.

	 * As of PHP 7.4.0, the Hash extension is a core PHP extension and can no

	 * longer be disabled.

	 * I.e. when PHP 7.4.0 becomes the minimum requirement, this polyfill

	 * and the associated `_hash_hmac()` function can be safely removed.

	 *

	 * @ignore

	 * @since 3.2.0

	 *

	 * @see _hash_hmac()

	 *

	 */

	}

endif;

/**

 * Internal compat function to mimic hash_hmac().

 *

 * @ignore

 * @since 3.2.0

 *

 */

	$packs = array(

		'md5'  => 'H32',

		'sha1' => 'H40',

	);

	if ( ! isset( $packs[ $algo ] ) ) {

		return false;

	}

	$pack = $packs[ $algo ];

	if ( strlen( $key ) > 64 ) {

		$key = pack( $pack, $algo( $key ) );

	}

	$key = str_pad( $key, 64, chr( 0 ) );

	$ipad = ( substr( $key, 0, 64 ) ^ str_repeat( chr( 0x36 ), 64 ) );

	$opad = ( substr( $key, 0, 64 ) ^ str_repeat( chr( 0x5C ), 64 ) );

	$hmac = $algo( $opad . pack( $pack, $algo( $ipad . $data ) ) );

		return pack( $pack, $hmac );

	}

	return $hmac;

}

if ( ! function_exists( 'hash_equals' ) ) :

	/**

	 *

	 * Compares two strings using the same time whether they're equal or not.

	 *

	 * Note: It can leak the length of a string when arguments of differing length are supplied.

	 *

	 * This function was added in PHP 5.6.

	 * However, the Hash extension may be explicitly disabled on select servers.

	 * As of PHP 7.4.0, the Hash extension is a core PHP extension and can no

	 * longer be disabled.

	 * I.e. when PHP 7.4.0 becomes the minimum requirement, this polyfill

	 * can be safely removed.

	 *

	 * @since 3.9.2

	 *

	 * @return bool Whether strings are equal.

	 */

			return false;

		}

		$result = 0;

		// Do not attempt to "optimize" this.

		}

		return 0 === $result;

	}

endif;

// sodium_crypto_box() was introduced in PHP 7.2.

if ( ! function_exists( 'sodium_crypto_box' ) ) {

	require ABSPATH . WPINC . '/sodium_compat/autoload.php';

}

if ( ! function_exists( 'is_countable' ) ) {

	/**

	 * Polyfill for is_countable() function added in PHP 7.3.

	 *

	 * Verify that the content of a variable is an array or an object

	 * implementing the Countable interface.

	 *

	 * @since 4.9.6

	 *

	 */

		);

	}

}

if ( ! function_exists( 'array_key_first' ) ) {

	/**

	 * Polyfill for array_key_first() function added in PHP 7.3.

	 *

	 * Get the first key of the given array without affecting

	 * the internal array pointer.

	 *

	 * @since 5.9.0

	 *

	 * @return string|int|null The first key of array if the array

	 *                         is not empty; `null` otherwise.

	 */

			return $key;

		}

	}

}

if ( ! function_exists( 'array_key_last' ) ) {

	/**

	 * Polyfill for `array_key_last()` function added in PHP 7.3.