current_streak_for_month.sql

CREATE OR REPLACE FUNCTION current_streak_for_month(x integer, as_of date) RETURNS INTEGER AS
$$
DECLARE
    shifted_checkin bigint;
    rightmost_zero bigint;
BEGIN
    shifted_checkin := x >> 31 - day_of_month(as_of);
    rightmost_zero := ~shifted_checkin & (shifted_checkin + 1);
    RETURN log(2, rightmost_zero)::INTEGER;
END
$$ LANGUAGE 'plpgsql';