Selecting ip address octets

Original - SQL Code CREATE OR REPLACE FUNCTION getClassB (ip IN VARCHAR2 default NULL) return varchar2 /* Author:Jonathon Wright Version: (Release) 1.0.0 Notes: Takes in a VARCHAR IP, returns class B String Would be same as "anding" the ip with 255.255.0.0 LEAVE THIS IN HEADER. FOR QUESTIONS: jonathon.wright@us.army.mil */ IS posA NUMBER; --position in string to end of first octet posB NUMBER; --position in string to end of second octet first_octet VARCHAR2(3); second_octet VARCHAR2(3); classB VARCHAR2(20); BEGIN --get position to first period select instr(ip,'.') into posA from dual; --get first octet select substr(ip, 1, posA - 1) into first_octet from dual; --get position to 2nd period select instr(substr(ip, posA + 1),'.') into posB from dual; --get 2nd octet select substr(ip,posA + 1, posB - 1) into second_octet from dual; --return classB classB := first_octet || '.' || second_octet || '.0.0'; return classB; exception when others then dbms_output.put_line('SQLERR:'|| SQLCODE || '-' || SQLERRM); END getClassB; /

CREATE OR REPLACE FUNCTION getClassB (ip IN VARCHAR2 DEFAULT NULL) RETURN varchar2
 
 
/*
  Author:Jonathon Wright
  Version: (Release) 1.0.0
  Notes: Takes in a VARCHAR IP, returns class B String
    Would be same as "anding" the ip with 255.255.0.0
    
    LEAVE THIS IN HEADER. FOR QUESTIONS: jonathon.wright@us.army.mil
*/
IS
 
posA NUMBER; --position in string to end of first octet
posB NUMBER; --position in string to end of second octet
first_octet  VARCHAR2(3);
second_octet VARCHAR2(3);
classB  VARCHAR2(20);
 
 
BEGIN
 
--get position to first period
SELECT instr(ip,'.') INTO posA FROM dual;
 
--get first octet
SELECT substr(ip, 1, posA - 1) INTO first_octet FROM dual;
 
--get position to 2nd period
SELECT instr(substr(ip, posA + 1),'.') INTO posB FROM dual;
 
--get 2nd octet
SELECT substr(ip,posA + 1, posB - 1) INTO second_octet FROM dual;
 
--return classB
classB := first_octet || '.' || second_octet || '.0.0';
 
RETURN classB;
 
exception WHEN others THEN
dbms_output.put_line('SQLERR:'|| SQLCODE || '-' || SQLERRM);
 
END getClassB;
/