Firebird SQL – URL parse procedure

create or alter procedure SP_PARSE_URL
(
  p_url VARCHAR(32000)
)
RETURNS (
  protocol VARCHAR(10),
  host VARCHAR(255),
  path VARCHAR(32000)
)
AS
BEGIN
  IF (POSITION('://' IN p_url) > 0) THEN
    protocol = SUBSTRING(p_url FROM 1 FOR POSITION('://' IN p_url) - 1);
  ELSE
    protocol = '';

  IF (POSITION('://' IN p_url) > 0) THEN
    p_url = SUBSTRING(p_url FROM POSITION('://' IN p_url) + 3);
  ELSE
    p_url = p_url;

  IF (POSITION('/' IN p_url) > 0) THEN
  BEGIN
    host = SUBSTRING(p_url FROM 1 FOR POSITION('/' IN p_url) - 1);
    p_url = SUBSTRING(p_url FROM POSITION('/' IN p_url));
  END
  ELSE
  BEGIN
    host = p_url;
    p_url = '';
  END

  path = p_url;

  SUSPEND;
END