根据上面的代码写一段Murmurhash3的Oracle函数

根据上面提供的C++代码，以下是一个Oracle PL/SQL版本的Murmurhash3函数示例：

CREATE OR REPLACE FUNCTION Murmurhash3(input_data IN VARCHAR2, seed IN NUMBER) RETURN NUMBER
IS
  h NUMBER := seed;
  c1 NUMBER := 0xcc9e2d51;
  c2 NUMBER := 0x1b873593;
  r1 NUMBER := 15;
  r2 NUMBER := 13;
  m NUMBER := 5;
  n NUMBER := 0xe6546b64;
  blkNums NUMBER := LENGTH(input_data) / 4;
  remaining_bytes VARCHAR2(4);
  K NUMBER;
  k NUMBER := 0;
BEGIN
  FOR i IN 0..blkNums-1 LOOP
    K := TO_NUMBER(SUBSTR(input_data, i*4+1, 4), 'xxxxxxxx');
    K := K * c1;
    K := BITAND(K, 4294967295);
    K := BITAND(K SHL r1, 4294967295);
    K := K * c2;
    K := BITAND(K, 4294967295);
    K := BITAND(K SHL r2, 4294967295);
    h := BITAND(h * m + n, 4294967295);
    h := BITAND(h + K, 4294967295);
  END LOOP;
  
  remaining_bytes := SUBSTR(input_data, blkNums*4+1);
  CASE LENGTH(remaining_bytes)
    WHEN 1 THEN k := TO_NUMBER(remaining_bytes, 'xx');
    WHEN 2 THEN k := TO_NUMBER(SUBSTR(remaining_bytes, 1, 1), 'xx')*256 
                    + TO_NUMBER(SUBSTR(remaining_bytes, 2, 1), 'xx');
    WHEN 3 THEN k := TO_NUMBER(SUBSTR(remaining_bytes, 1, 1), 'xx')*65536 
                    + TO_NUMBER(SUBSTR(remaining_bytes, 2, 1), 'xx')*256 
                    + TO_NUMBER(SUBSTR(remaining_bytes, 3, 1), 'xx');
  END CASE;
  k := BITAND(k * c1, 4294967295);
  k := BITAND(k SHL r1, 4294967295);
  k := BITAND(k * c2, 4294967295);
  h := BITAND(h XOR k, 4294967295);
  h := BITAND(h XOR LENGTH(input_data), 4294967295);
  h := BITAND(h XOR BITRSHIFT(h, 16), 4294967295);
  h := BITAND(h * 0x85ebca6b, 4294967295);
  h := BITAND(h XOR BITRSHIFT(h, 13), 4294967295);
  h := BITAND(h * 0xc2b2ae35, 4294967295);
  h := BITAND(h XOR BITRSHIFT(h, 16), 4294967295);
  
  RETURN h;
END;

在Oracle PL/SQL中，需要使用位运算符BITAND和BITRSHIFT来替代C++代码中的位运算符，同时需要注意数据类型的转换和溢出问题。以上示例代码可能并不是最优的实现方式，但可以作为参考，供实际使用时进行优化和改进。