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.
Somethinglike 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