写一个MurmurHash3的存储过程
时间: 2023-07-06 22:41:05 浏览: 53
以下是一个使用MySQL编写的MurmurHash3的存储过程:
```
DELIMITER $$
CREATE PROCEDURE murmurhash3(IN input CHAR(255), IN seed INT, OUT hash BIGINT)
BEGIN
DECLARE c1 BIGINT UNSIGNED DEFAULT 0x87c37b91;
DECLARE c2 BIGINT UNSIGNED DEFAULT 0x4cf5ad43;
DECLARE r1 INT UNSIGNED DEFAULT 15;
DECLARE r2 INT UNSIGNED DEFAULT 13;
DECLARE m BIGINT UNSIGNED DEFAULT 5;
DECLARE n BIGINT UNSIGNED DEFAULT 0xe6546b64;
DECLARE len INT UNSIGNED;
DECLARE i INT UNSIGNED;
DECLARE k BIGINT UNSIGNED;
DECLARE remaining CHAR(4) DEFAULT '';
SET len = LENGTH(input);
SET hash = seed;
FOR i = 1 TO FLOOR(len/4) DO
SET k = CONV(SUBSTR(input, (i-1)*4+1, 4), 16, 10);
SET k = k * c1;
SET k = (k << r1) | (k >> (32 - r1));
SET k = k * c2;
SET hash = hash XOR k;
SET hash = (hash << r2) | (hash >> (32 - r2));
SET hash = hash * m + n;
END FOR;
IF len % 4 = 3 THEN
SET remaining = CONCAT(SUBSTR(input, len-2), '\x00');
ELSEIF len % 4 = 2 THEN
SET remaining = CONCAT(SUBSTR(input, len-1), '\x00\x00');
ELSEIF len % 4 = 1 THEN
SET remaining = CONCAT(SUBSTR(input, len), '\x00\x00\x00');
END IF;
SET k = CONV(remaining, 16, 10);
SET k = k * c1;
SET k = (k << r1) | (k >> (32 - r1));
SET k = k * c2;
SET hash = hash XOR k;
SET hash = hash XOR len;
SET hash = hash XOR (hash >> 16);
SET hash = hash * 0x85ebca6b;
SET hash = hash XOR (hash >> 13);
SET hash = hash * 0xc2b2ae35;
SET hash = hash XOR (hash >> 16);
END$$
DELIMITER ;
```
该存储过程接受输入字符串和哈希种子,输出MurmurHash3的哈希值。它使用了与前面伪代码相似的方法进行处理,但是需要注意MySQL中的数据类型和函数的使用。同时,该存储过程只支持长度小于等于255的输入字符串,如果需要处理更长的字符串,可以进行适当的调整。