PG Cast Helpers

bit2text.sql

CREATE OR REPLACE FUNCTION bit2text(BIT VARYING)
  RETURNS TEXT
AS $$
SELECT textin(bit_out($1));
$$ LANGUAGE 'sql';

bit_count.sql

CREATE OR REPLACE FUNCTION bit_count(bitVal BIT VARYING)
  RETURNS INTEGER AS $$
  BEGIN
    RETURN LENGTH( REPLACE( CAST( bitVal AS TEXT ), '0',''));
  END;
  $$ LANGUAGE 'plpgsql' IMMUTABLE STRICT;

hex_to_bit.sql

CREATE OR REPLACE FUNCTION hex_to_bit(hexVal VARCHAR)
  RETURNS BIT VARYING AS $$
DECLARE
  bitResult BIT VARYING := 0;
  hexLength INTEGER;
  i         INTEGER;
  hexDigit  VARCHAR;
BEGIN
  hexLength := length(hexVal);

  FOR i IN 1..hexLength
  LOOP
    hexDigit := substr(hexVal, hexLength - i + 1, 1);
    IF i = 1
    THEN
      bitResult := B'000' || bitResult;
    ELSE
      bitResult := B'0000' || bitResult;
    END IF;
    bitResult := bitResult |
                 text2bitstring(rpad(bit2text((('X' || hexDigit) :: BIT(4))), i * 4, '0'));
  END LOOP;

  RETURN bitResult;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE STRICT;

text2bit.sql

CREATE OR REPLACE FUNCTION text2bitstring(TEXT)
  RETURNS BIT VARYING
AS $$
SELECT bit_in(textout('B' :: TEXT || $1), 67, length($1));
$$ LANGUAGE 'sql';
COMMENT ON FUNCTION text2bitstring(TEXT) IS 'Convert text (contianing 1''s and 0''s only) to a bit varying type.';