Cookie::domain_matches( string $domain )

	public function domain_matches($domain) {
		if (is_string($domain) === false) {
			return false;
		}

		if (!isset($this->attributes['domain'])) {
			// Cookies created manually; cookies created by Requests will set
			// the domain to the requested domain
			return true;
		}

		$cookie_domain = $this->attributes['domain'];
		if ($cookie_domain === $domain) {
			// The cookie domain and the passed domain are identical.
			return true;
		}

		// If the cookie is marked as host-only and we don't have an exact
		// match, reject the cookie
		if ($this->flags['host-only'] === true) {
			return false;
		}

		if (strlen($domain) <= strlen($cookie_domain)) {
			// For obvious reasons, the cookie domain cannot be a suffix if the passed domain
			// is shorter than the cookie domain
			return false;
		}

		if (substr($domain, -1 * strlen($cookie_domain)) !== $cookie_domain) {
			// The cookie domain should be a suffix of the passed domain.
			return false;
		}

		$prefix = substr($domain, 0, strlen($domain) - strlen($cookie_domain));
		if (substr($prefix, -1) !== '.') {
			// The last character of the passed domain that is not included in the
			// domain string should be a %x2E (".") character.
			return false;
		}

		// The passed domain should be a host name (i.e., not an IP address).
		return !preg_match('#^(.+\.)\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$#', $domain);
	}