public static function codePointBefore($chars, int $index, int $start = null): int
    {
        if ($start !== null && ($start < 0 || $index <= $start)) {
            throw new InvalidArgumentException('Start cannot be negative and index must be greater than start!');
        }

        return static::codePointAt($chars, $index - 1);
    }
public static function codePointBefore($chars, int $index, int $start = null): int
    {
        if ($start !== null && ($start < 0 || $index <= $start)) {
            throw new InvalidArgumentException('Start cannot be negative and index must be greater than start!');
        }

        return static::codePointAt($chars, $index - 1);
    }
public static function codePointBefore ( $ chars , int $ index , int $ start = null ) : int { if ( $ start !== null && ( $ start < 0 || $ index <= $ start ) ) { throw new InvalidArgumentException ( 'Start cannot be negative and index must be greater than start!' ) ; } return static :: codePointAt ( $ chars , $ index - 1 ) ; }
Returns the unicode code point before specified index

@param CharSequence|static[] $chars
@param int                   $index
@param int                   $start
@return int
@throws InvalidArgumentException
Returns the unicode code point before specified index