public static function codepoint_to_utf8($codepoint)
	{
		$codepoint = (int) $codepoint;
		if ($codepoint < 0)
		{
			return false;
		}
		else if ($codepoint <= 0x7f)
		{
			return chr($codepoint);
		}
		else if ($codepoint <= 0x7ff)
		{
			return chr(0xc0 | ($codepoint >> 6)) . chr(0x80 | ($codepoint & 0x3f));
		}
		else if ($codepoint <= 0xffff)
		{
			return chr(0xe0 | ($codepoint >> 12)) . chr(0x80 | (($codepoint >> 6) & 0x3f)) . chr(0x80 | ($codepoint & 0x3f));
		}
		else if ($codepoint <= 0x10ffff)
		{
			return chr(0xf0 | ($codepoint >> 18)) . chr(0x80 | (($codepoint >> 12) & 0x3f)) . chr(0x80 | (($codepoint >> 6) & 0x3f)) . chr(0x80 | ($codepoint & 0x3f));
		}
		else
		{
			// U+FFFD REPLACEMENT CHARACTER
			return "\xEF\xBF\xBD";
		}
	}