class TraceContextValidator

class TraceContextValidator {
    public const TRACE_FLAG_LENGTH = 2;
    public const TRACE_VERSION_REGEX = '/^(?!ff)[\\da-f]{2}$/';
    public static function isValidTraceVersion(string $traceVersion) : bool {
        return 1 === preg_match(self::TRACE_VERSION_REGEX, $traceVersion);
    }
    
    /**
     * @return bool Returns a value that indicates whether trace flag is valid
     * TraceFlags must be exactly 1 bytes (1 char) representing a bit field
     */
    public static function isValidTraceFlag(string $traceFlag) : bool {
        return ctype_xdigit($traceFlag) && strlen($traceFlag) === self::TRACE_FLAG_LENGTH;
    }

}