oracle 身份验证函数

CREATE OR REPLACE FUNCTION fn_checkidcard (p_idcard IN VARCHAR2)
   RETURN INT
IS
-------------------------------------
--
--身份证认证
--
--
------------------------------------
   v_regstr      VARCHAR2 (2000);
   v_sum         NUMBER;
   v_mod         NUMBER;
   v_checkcode   CHAR (11)       := '10X98765432';
   v_checkbit    CHAR (1);
   v_areacode    VARCHAR2 (2000) :='11,12,13,14,15,21,22,23,31,32,33,34,35,36,37,41,42,43,44,45,46,50,51,52,53,54,61,62,63,64,65,71,81,82,91,';
BEGIN
   CASE LENGTHB (p_idcard)
      WHEN 15
      THEN                                                            -- 15位
         IF INSTRB (v_areacode, SUBSTR (p_idcard, 1, 2) || ',') = 0
         THEN
            RETURN 0;
         END IF;

         IF    MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 2)) + 1900, 400) = 0
            OR (    MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 2)) + 1900, 100) <>
                                                                             0
                AND MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 2)) + 1900, 4) = 0
               )
         THEN                                                          -- 闰年
            v_regstr :=
               '^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}$';
         ELSE
            v_regstr :=
               '^[1-9][0-9]{5}[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}$';
         END IF;

         IF REGEXP_LIKE (p_idcard, v_regstr)
         THEN
            RETURN 1;
         ELSE
            RETURN 0;
         END IF;
      WHEN 18
      THEN                                                             -- 18位
         IF INSTRB (v_areacode, SUBSTRB (p_idcard, 1, 2) || ',') = 0
         THEN
            RETURN 0;
         END IF;

         IF    MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 4)), 400) = 0
            OR (    MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 4)), 100) <> 0
                AND MOD (TO_NUMBER (SUBSTRB (p_idcard, 6, 4)), 4) = 0
               )
         THEN                                                          -- 闰年
            v_regstr :=
               '^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|[1-2][0-9]))[0-9]{3}[0-9Xx]$';
         ELSE
            v_regstr :=
               '^[1-9][0-9]{5}19[0-9]{2}((01|03|05|07|08|10|12)(0[1-9]|[1-2][0-9]|3[0-1])|(04|06|09|11)(0[1-9]|[1-2][0-9]|30)|02(0[1-9]|1[0-9]|2[0-8]))[0-9]{3}[0-9Xx]$';
         END IF;

         IF REGEXP_LIKE (p_idcard, v_regstr)
         THEN
            v_sum :=
                   (  TO_NUMBER (SUBSTRB (p_idcard, 1, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 11, 1))
                   )
                 * 7
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 2, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 12, 1))
                   )
                 * 9
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 3, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 13, 1))
                   )
                 * 10
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 4, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 14, 1))
                   )
                 * 5
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 5, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 15, 1))
                   )
                 * 8
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 6, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 16, 1))
                   )
                 * 4
               +   (  TO_NUMBER (SUBSTRB (p_idcard, 7, 1))
                    + TO_NUMBER (SUBSTRB (p_idcard, 17, 1))
                   )
                 * 2
               + TO_NUMBER (SUBSTRB (p_idcard, 8, 1)) * 1
               + TO_NUMBER (SUBSTRB (p_idcard, 9, 1)) * 6
               + TO_NUMBER (SUBSTRB (p_idcard, 10, 1)) * 3;
            v_mod := MOD (v_sum, 11);
            v_checkbit := SUBSTRB (v_checkcode, v_mod + 1, 1);

            IF v_checkbit = SUBSTRB (p_idcard, 18, 1)
            THEN
               RETURN 1;
            ELSE
               RETURN 0;
            END IF;
         ELSE
            RETURN 0;
         END IF;
      ELSE
         RETURN 0;                                      -- 身份证号码位数不对
   END CASE;
EXCEPTION
   WHEN OTHERS
   THEN
      RETURN 0;
END fn_checkidcard;