6.6.0
	 *
	 * @param string $indent Optional. Use this string for indentation, or rely on the default horizontal tab character. Default "\t".
	 * @return string Value which can be pasted into a PHP source file for quick loading of table.
	 */
	public function precomputed_php_source_table( $indent = "\t" ) {
		$i1 = $indent;
		$i2 = $i1 . $indent;
		$i3 = $i2 . $indent;

		$class_version = self::STORAGE_VERSION;

		$output  = self::class . "::from_precomputed_table(\n";
		$output .= "{$i1}array(\n";
		$output .= "{$i2}\"storage_version\" => \"{$class_version}\",\n";
		$output .= "{$i2}\"key_length\" => {$this->key_length},\n";

		$group_line = str_replace( "\x00", "\\x00", $this->groups );
		$output    .= "{$i2}\"groups\" => \"{$group_line}\",\n";

		$output .= "{$i2}\"large_words\" => array(\n";

		$prefixes = explode( "\x00", $this->groups );
		foreach ( $prefixes as $index => $prefix ) {
			if ( '' === $prefix ) {
				break;
			}
			$group        = $this->large_words[ $index ];
			$group_length = strlen( $group );
			$comment_line = "{$i3}//";
			$data_line    = "{$i3}\"";
			$at           = 0;
			while ( $at < $group_length ) {
				$token_length   = unpack( 'C', $group[ $at++ ] )[1];
				$token          = substr( $group, $at, $token_length );
				$at            += $token_length;
				$mapping_length = unpack( 'C', $group[ $at++ ] )[1];
				$mapping        = substr( $group, $at, $mapping_length );
				$at            += $mapping_length;

				$token_digits   = str_pad( dechex( $token_length ), 2, '0', STR_PAD_LEFT );
				$mapping_digits = str_pad( dechex( $mapping_length ), 2, '0', STR_PAD_LEFT );

				$mapping = preg_replace_callback(
					"~[\\x00-\\x1f\\x22\\x5c]~",
					static function ( $match_result ) {
						switch ( $match_result[0] ) {
							case '"':
								return '\\"';

							case '\\':
								return '\\\\';

							default:
								$hex = dechex( ord( $match_result[0] ) );
								return "\\x{$hex}";
						}
					},
					$mapping
				);

				$comment_line .= " {$prefix}{$token}[{$mapping}]";
				$data_line    .= "\\x{$token_digits}{$token}\\x{$mapping_digits}{$mapping}";
			}
			$comment_line .= ".\n";
			$data_line    .= "\",\n";

			$output .= $comment_line;
			$output .= $data_line;
		}

		$output .= "{$i2}),\n";

		$small_words  = array();
		$small_length = strlen( $this->small_words );
		$at           = 0;
		while ( $at < $small_length ) {
			$small_words[] = substr( $this->small_words, $at, $this->key_length + 1 );
			$at           += $this->key_length + 1;
		}

		$small_text = str_replace( "\x00", '\x00', implode( '', $small_words ) );
		$output    .= "{$i2}\"small_words\" => \"{$small_text}\",\n";

		$output .= "{$i2}\"small_mappings\" => array(\n";
		foreach ( $this->small_mappings as $mapping ) {
			$output .= "{$i3}\"{$mapping}\",\n";
		}
		$output .= "{$i2})\n";
		$output .= "{$i1})\n";
		$output .= ')';

		return $output;
	}

	/**
	 * Compares two strings, returning the longest, or whichever
	 * is first alphabetically if they are the same length.
	 *
	 * This is an important sort when building the token map because
	 * it should not form a match on a substring of a longer potential
	 * match. For example, it should not detect `Cap` when matching
	 * against the string `CapitalDifferentialD`.
	 *
	 * @since 6.6.0
	 *
	 * @param string $a First string to compare.
	 * @param string $b Second string to compare.
	 * @return int -1 or lower if `$a` is less than `$b`; 1 or greater if `$a` is greater than `$b`, and 0 if they are equal.
	 */
	private static function longest_first_then_alphabetical( $a, $b ) {
		if ( $a === $b ) {
			return 0;
		}

		$length_a = strlen( $a );
		$length_b = strlen( $b );

		// Longer strings are less-than for comparison's sake.
		if ( $length_a !== $length_b ) {
			return $length_b - $length_a;
		}

		return strcmp( $a, $b );
	}
}
URL if headers are sent. Returns false
 *                      if headers are not sent.
 */
function send_origin_headers() {
	$origin = get_http_origin();

	if ( is_allowed_http_origin( $origin ) ) {
		header( 'Access-Control-Allow-Origin: ' . $origin );
		header( 'Access-Control-Allow-Credentials: true' );
		if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
			exit;
		}
		return $origin;
	}

	if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
		status_header( 403 );
		exit;
	}

	return false;
}

/**
 * Validates a URL for safe use in the HTTP API.
 *
 * Examples of URLs that are considered unsafe:
 *
 * - ftp://example.com/caniload.php - Invalid protocol - only http and https are allowed.
 * - http:///example.com/caniload.php - Malformed URL.
 * - http://user:pass@example.com/caniload.php - Login information.
 * - http://exampleeeee.com/caniload.php - Invalid hostname, as the IP cannot be looked up in DNS.
 *
 * Examples of URLs that are considered unsafe by default:
 *
 * - http://192.168.0.1/caniload.php - IPs from LAN networks.
 *   This can be changed with the {@see 'http_request_host_is_external'} filter.
 * - http://198.143.164.252:81/caniload.php - By default, only 80, 443, and 8080 ports are allowed.
 *   This can be changed with the {@see 'http_allowed_safe_ports'} filter.
 *
 * @since 3.5.2
 *
 * @param string $url Request URL.
 * @return string|false URL or false on failure.
 */
function wp_http_validate_url( $url ) {
	if ( ! is_string( $url ) || '' === $url || is_numeric( $url ) ) {
		return false;
	}

	$original_url = $url;
	$url          = wp_kses_bad_protocol( $url, array( 'http', 'https' ) );
	if ( ! $url || strtolower( $url ) !== strtolower( $original_url ) ) {
		return false;
	}

	$parsed_url = parse_url( $url );
	if ( ! $parsed_url || empty( $parsed_url['host'] ) ) {
		return false;
	}

	if ( isset( $parsed_url['user'] ) || isset( $parsed_url['pass'] ) ) {
		return false;
	}

	if ( false !== strpbrk( $parsed_url['host'], ':#?[]' ) ) {
		return false;
	}

	$parsed_home = parse_url( get_option( 'home' ) );
	$same_host   = isset( $parsed_home['host'] ) && strtolower( $parsed_home['host'] ) === strtolower( $parsed_url['host'] );
	$host        = trim( $parsed_url['host'], '.' );

	if ( ! $same_host ) {
		if ( preg_match( '#^(([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)\.){3}([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)$#', $host ) ) {
			$ip = $host;
		} else {
			$ip = gethostbyname( $host );
			if ( $ip === $host ) { // Error condition for gethostbyname().
				return false;
			}
		}
		if ( $ip ) {
			$parts = array_map( 'intval', explode( '.', $ip ) );
			if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]
				|| ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
				|| ( 192 === $parts[0] && 168 === $parts[1] )
			) {
				// If host appears local, reject unless specifically allowed.
				/**
				 * Checks if HTTP request is external or not.
				 *
				 * Allows to change and allow external requests for the HTTP request.
				 *
				 * @since 3.6.0
				 *
				 * @param bool   $external Whether HTTP request is external or not.
				 * @param string $host     Host name of the requested URL.
				 * @param string $url      Requested URL.
				 */
				if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {
					return false;
				}
			}
		}
	}

	if ( empty( $parsed_url['port'] ) ) {
		return $url;
	}

	$port = $parsed_url['port'];

	/**
	 * Controls the list of ports considered safe in HTTP API.
	 *
	 * Allows to change and allow external requests for the HTTP request.
	 *
	 * @since 5.9.0
	 *
	 * @param int[]  $allowed_ports Array of integers for valid ports.
	 * @param string $host          Host name of the requested URL.
	 * @param string $url           Requested URL.
	 */
	$allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
	if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
		return $url;
	}

	if ( $parsed_home && $same_host && isset( $parsed_home['port'] ) && $parsed_home['port'] === $port ) {
		return $url;
	}

	return false;
}

/**
 * Marks allowed redirect hosts safe for HTTP requests as well.
 *
 * Attached to the {@see 'http_request_host_is_external'} filter.
 *
 * @since 3.6.0
 *
 * @param bool   $is_external
 * @param string $host
 * @return bool
 */
function allowed_http_request_hosts( $is_external, $host ) {
	if ( ! $is_external && wp_validate_redirect( 'http://' . $host ) ) {
		$is_external = true;
	}
	return $is_external;
}

/**
 * Adds any domain in a multisite installation for safe HTTP requests to the
 * allowed list.
 *
 * Attached to the {@see 'http_request_host_is_external'} filter.
 *
 * @since 3.6.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param bool   $is_external
 * @param string $host
 * @return bool
 */
function ms_allowed_http_request_hosts( $is_external, $host ) {
	global $wpdb;
	static $queried = array();
	if ( $is_external ) {
		return $is_external;
	}
	if ( get_network()->domain === $host ) {
		return true;
	}
	if ( isset( $queried[ $host ] ) ) {
		return $queried[ $host ];
	}
	$queried[ $host ] = (bool) $wpdb->get_var( $wpdb->prepare( "SELECT domain FROM $wpdb->blogs WHERE domain = %s LIMIT 1", $host ) );
	return $queried[ $host ];
}

/**
 * A wrapper for PHP's parse_url() function that handles consistency in the return values
 * across PHP versions.
 *
 * PHP 5.4.7 expanded parse_url()'s ability to handle non-absolute URLs, including
 * schemeless and relative URLs with "://" in the path. This function works around
 * those limitations providing a standard output on PHP 5.2~5.4+.
 *
 * Secondly, across various PHP versions, schemeless URLs containing a ":" in the query
 * are being handled inconsistently. This function works around those differences as well.
 *
 * @since 4.4.0
 * @since 4.7.0 The `$component` parameter was added for parity with PHP's `parse_url()`.
 *
 * @link https://www.php.net/manual/en/function.parse-url.php
 *
 * @param string $url       The URL to parse.
 * @param int    $component The specific component to retrieve. Use one of the PHP
 *                          predefined constants to specify which one.
 *                          Defaults to -1 (= return all parts as an array).
 * @return mixed False on parse failure; Array of URL components on success;
 *               When a specific component has been requested: null if the component
 *               doesn't exist in the given URL; a string or - in the case of
 *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 */
function wp_parse_url( $url, $component = -1 ) {
	$to_unset = array();
	$url      = (string) $url;

	if ( str_starts_with( $url, '//' ) ) {
		$to_unset[] = 'scheme';
		$url        = 'placeholder:' . $url;
	} elseif ( str_starts_with( $url, '/' ) ) {
		$to_unset[] = 'scheme';
		$to_unset[] = 'host';
		$url        = 'placeholder://placeholder' . $url;
	}

	$parts = parse_url( $url );

	if ( false === $parts ) {
		// Parsing failure.
		return $parts;
	}

	// Remove the placeholder values.
	foreach ( $to_unset as $key ) {
		unset( $parts[ $key ] );
	}

	return _get_component_from_parsed_url_array( $parts, $component );
}

/**
 * Retrieves a specific component from a parsed URL array.
 *
 * @internal
 *
 * @since 4.7.0
 * @access private
 *
 * @link https://www.php.net/manual/en/function.parse-url.php
 *
 * @param array|false $url_parts The parsed URL. Can be false if the URL failed to parse.
 * @param int         $component The specific component to retrieve. Use one of the PHP
 *                               predefined constants to specify which one.
 *                               Defaults to -1 (= return all parts as an array).
 * @return mixed False on parse failure; Array of URL components on success;
 *               When a specific component has been requested: null if the component
 *               doesn't exist in the given URL; a string or - in the case of
 *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 */
function _get_component_from_parsed_url_array( $url_parts, $component = -1 ) {
	if ( -1 === $component ) {
		return $url_parts;
	}

	$key = _wp_translate_php_url_constant_to_key( $component );
	if ( false !== $key && is_array( $url_parts ) && isset( $url_parts[ $key ] ) ) {
		return $url_parts[ $key ];
	} else {
		return null;
	}
}

/**
 * Translates a PHP_URL_* constant to the named array keys PHP uses.
 *
 * @internal
 *
 * @since 4.7.0
 * @access private
 *
 * @link https://www.php.net/manual/en/url.constants.php
 *
 * @param int $constant PHP_URL_* constant.
 * @return string|false The named key or false.
 */
function _wp_translate_php_url_constant_to_key( $constant ) {
	$translation = array(
		PHP_URL_SCHEME   => 'scheme',
		PHP_URL_HOST     => 'host',
		PHP_URL_PORT     => 'port',
		PHP_URL_USER     => 'user',
		PHP_URL_PASS     => 'pass',
		PHP_URL_PATH     => 'path',
		PHP_URL_QUERY    => 'query',
		PHP_URL_FRAGMENT => 'fragment',
	);

	if ( isset( $translation[ $constant ] ) ) {
		return $translation[ $constant ];
	} else {
		return false;
	}
}