Postgresql string parsing

Hi Folks,
I'm looking for the fatest way to parse string in a postgresql function and insert each parsed chunk in a table. Something like that:

CREATE FUNCTION parse_and_insert(text) RETURNS integer AS '

DECLARE
my_string ALIAS FOR $1;

-- empty string, do nothing
IF my_string IS NULL THEN
-- split my_string at each new line char '\n', '\r\n' or '\r'

-- loop for each founded chunk, and simply insert it
INSERT INTO tableX (data) VALUES (chunk);

return 1;
END IF;

-- empty string, do nothing
return 0;

END;
' LANGUAGE 'plpgsql';

My be there is exists complety different and fasted method?

Thanks in advance guys

/Youn