numeric_bitwise_functions.sql

-- implementation of bitwise & operator for the numeric data type
create or replace function numeric_and(leftarg numeric, rightarg numeric) returns numeric as
$$
declare
    width  int     := 32;
    modulo bigint  := 2 ^ width;
    b1     bigint  := 0;
    b2     bigint  := 0;
    r      numeric := 0;
    i      integer := 0;
begin
    while leftarg != 0 and rightarg != 0
        loop
            b1 := leftarg % modulo;
            b2 := rightarg % modulo;
            r := r + ((b1 & b2)::numeric << (width * i));
            leftarg = leftarg >> width;
            rightarg = rightarg >> width;
            i := i + 1;
        end loop;
    return r;
end;
$$ language plpgsql;


create operator & (
    function = numeric_and,
    leftarg = numeric,
    rightarg = numeric
    );


-- implementation of bitwise | operator for the numeric data type
create or replace function numeric_or(leftarg numeric, rightarg numeric) returns numeric as
$$
declare
    width  int     := 32;
    modulo bigint  := 2 ^ width;
    b1     bigint  := 0;
    b2     bigint  := 0;
    r      numeric := 0;
    i      integer := 0;
begin
    while leftarg != 0 or rightarg != 0
        loop
            b1 := leftarg % modulo;
            b2 := rightarg % modulo;
            r := r + ((b1 | b2)::numeric << (width * i));
            leftarg = leftarg >> width;
            rightarg = rightarg >> width;
            i := i + 1;
        end loop;
    return r;
end;
$$ language plpgsql;


create operator | (
    function = numeric_or,
    leftarg = numeric,
    rightarg = numeric
    );


-- implementation of bitwise # operator for the numeric data type
create or replace function numeric_xor(leftarg numeric, rightarg numeric) returns numeric as
$$
declare
    width  int     := 32;
    modulo bigint  := 2 ^ width;
    b1     bigint  := 0;
    b2     bigint  := 0;
    r      numeric := 0;
    i      integer := 0;
begin
    while leftarg != 0 or rightarg != 0
        loop
            b1 := leftarg % modulo;
            b2 := rightarg % modulo;
            r := r + ((b1 # b2)::numeric << (width * i));
            leftarg = leftarg >> width;
            rightarg = rightarg >> width;
            i := i + 1;
        end loop;
    return r;
end;
$$ language plpgsql;


create operator # (
    function = numeric_xor,
    leftarg = numeric,
    rightarg = numeric
    );


-- implementation of bitwise >> operator for the numeric data type
create or replace function numeric_shift_right(leftarg numeric, rightarg numeric) returns numeric as
$$
begin
    return floor(leftarg / (2 ^ rightarg));
end;
$$ language plpgsql;


create operator >> (
    function = numeric_shift_right,
    leftarg = numeric,
    rightarg = numeric
    );


-- implementation of bitwise << operator for the numeric data type
create or replace function numeric_shift_left(leftarg numeric, rightarg numeric) returns numeric as
$$
begin
    return leftarg * (2 ^ rightarg);
end;
$$ language plpgsql;


create operator << (
    function = numeric_shift_left,
    leftarg = numeric,
    rightarg = numeric
    );
    
do
$$
    begin
        assert 129401205912050919051920510251920501925::numeric &
               12591205901209501209490409120949109249012040124::numeric = 375224963989548894071315746773172388;
        assert 129401205912050919051920510251920501925::numeric #
               12591205901209501209490409120949109249012040124::numeric = 12591206029860257193562230384726988007386197273;
        assert 129401205912050919051920510251920501925::numeric | 
               12591205901209501209490409120949109249012040124::numeric = 12591206030235482157551779278798303754159369661;
        assert 129401205912050919051920510251920501925::numeric >> 27 = 964114113986871533482674585669;
        assert 129401205912050919051920510251920501925::numeric << 27 = 17367935857975642175460684922613477404993126400;
    end;
$$;