MySQL 计算CRC16的函数
MySQL function to calculate CRC16
我在一个使用大型 MySQL 数据库的系统上工作，我需要根据 table 中的某些列计算 crc16。但我找不到任何对我有帮助的功能。 MySQL只有crc32，但我需要CRC16/ARC
我试图创建一个 SQL 代码来计算我在 Java 和 C# 中的 CRC16，但没有成功。
有人可以帮助我吗？
谢谢！
--- 已编辑 ------------------
SQL 中的代码来自 MySQL try...
CREATE FUNCTION `fn_crc16`(pValue varchar(255)) RETURNS varchar(50) CHARSET utf8mb4
BEGIN
declare retval, b binary;
declare c char(1) default '';
declare i, len integer default 0;
set retval = 0x0000;
set len = length(pValue);
set i = 1;
repeat
set c = substring(pValue, i, 1);
set b = (retval ^ cast(c as binary)) & 0xff;
select value into b from tbl_crc16 where idx = b;
set retval = b ^ (retval >> 8);
set i = i + 1;
until i > len end repeat;
set retval = retval & 0xffff;
return hex(retval);
END
tbl_crc16 是一个十六进制代码列表。
我的 Java 和 C# 代码生成相同的 CRC16 十六进制值。
这是我在 Java 中为 Android 实现的 CRC16。
public class Crc16 {
static int[] table = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
};
public static String hash(String s) {
byte[] bytes = s.getBytes();
int crc16 = 0x0000;
for (byte b : bytes)
crc16 = table[(crc16 ^ b) & 0xff] ^ (crc16 >> 8);
crc16 = crc16 & 0xFFFF;
return Integer.toHexString(crc16);
}
}
如果您根据您的函数对 varchars 进行操作，那么这将起作用：
declare retval, b, c integer;
declare i, len integer default 0;
set retval = 0x0000;
set len = length(pValue);
set i = 1;
repeat
set c = ascii(substring(pValue, i, 1));
set b = (retval ^ c) & 0xff;
select value into b from tbl_crc16 where idx = b + 1; -- my idx starts at 1
set retval = b ^ (retval >> 8);
set i = i + 1;
until i > len end repeat;
set retval = retval & 0xffff;
return hex(retval);
备注：
- 我的tbl_crc16的idx从1开始；如果您的条件从 0
开始，则将 where 条件更改为 idx = b
binary 您用于 retval 的数据类型和 b 是单字节类型，这就是它不起作用的原因；我正在使用整数
Live example via dbfiddle.uk, checks out with https://crccalc.com
这实现了 CRC16/modbus，无需使用 table
DELIMITER //
CREATE DEFINER=`root`@`%` FUNCTION `CRC16`( _STRING VARCHAR(25)) RETURNS varchar(50) CHARSET utf8mb4
DETERMINISTIC
BEGIN
DECLARE _myCRC integer;
DECLARE _ord INTEGER;
DECLARE _n Integer;
DECLARE _m Integer;
DECLARE _strlend Integer;
SET _myCRC := x'FFFF';
SET _n := 1;
SET _strlend := LENGTH(_STRING) ;
loop_crc: LOOP
IF _n > _strlend THEN
LEAVE loop_crc;
END IF;
SET _ord := ORD(SUBSTRING(_STRING, _n, 1) );
SET _myCRC := _myCRC ^ _ord;
SET _m := 0;
loop_bit: LOOP
IF _m = 8 THEN
LEAVE loop_bit;
END IF;
IF (_myCRC & x'0001') = x'0001' THEN
SET _myCRC := (_myCRC >> 1) ^ x'A001';
ELSE
SET _myCRC := _myCRC >> 1;
END IF;
SET _m := _m + 1;
END LOOP;
SET _n := _n + 1;
END LOOP;
return HEX(_myCRC);
END//
DELIMITER ;
查询SELECT CRC16("A");
Returns
CRC16("A")
707F
您可以在 https://crccalc.com/ 中查看结果，或者使用您自己在 java 或 C#
中的结果
我在一个使用大型 MySQL 数据库的系统上工作，我需要根据 table 中的某些列计算 crc16。但我找不到任何对我有帮助的功能。 MySQL只有crc32，但我需要CRC16/ARC
我试图创建一个 SQL 代码来计算我在 Java 和 C# 中的 CRC16，但没有成功。
有人可以帮助我吗？ 谢谢！
--- 已编辑 ------------------
SQL 中的代码来自 MySQL try...
CREATE FUNCTION `fn_crc16`(pValue varchar(255)) RETURNS varchar(50) CHARSET utf8mb4
BEGIN
declare retval, b binary;
declare c char(1) default '';
declare i, len integer default 0;
set retval = 0x0000;
set len = length(pValue);
set i = 1;
repeat
set c = substring(pValue, i, 1);
set b = (retval ^ cast(c as binary)) & 0xff;
select value into b from tbl_crc16 where idx = b;
set retval = b ^ (retval >> 8);
set i = i + 1;
until i > len end repeat;
set retval = retval & 0xffff;
return hex(retval);
END
tbl_crc16 是一个十六进制代码列表。
我的 Java 和 C# 代码生成相同的 CRC16 十六进制值。
这是我在 Java 中为 Android 实现的 CRC16。
public class Crc16 {
static int[] table = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
};
public static String hash(String s) {
byte[] bytes = s.getBytes();
int crc16 = 0x0000;
for (byte b : bytes)
crc16 = table[(crc16 ^ b) & 0xff] ^ (crc16 >> 8);
crc16 = crc16 & 0xFFFF;
return Integer.toHexString(crc16);
}
}
如果您根据您的函数对 varchars 进行操作，那么这将起作用：
declare retval, b, c integer;
declare i, len integer default 0;
set retval = 0x0000;
set len = length(pValue);
set i = 1;
repeat
set c = ascii(substring(pValue, i, 1));
set b = (retval ^ c) & 0xff;
select value into b from tbl_crc16 where idx = b + 1; -- my idx starts at 1
set retval = b ^ (retval >> 8);
set i = i + 1;
until i > len end repeat;
set retval = retval & 0xffff;
return hex(retval);
备注：
- 我的tbl_crc16的idx从1开始；如果您的条件从 0 开始，则将 where 条件更改为 idx = b
binary您用于 retval 的数据类型和 b 是单字节类型，这就是它不起作用的原因；我正在使用整数
Live example via dbfiddle.uk, checks out with https://crccalc.com
这实现了 CRC16/modbus，无需使用 table
DELIMITER //
CREATE DEFINER=`root`@`%` FUNCTION `CRC16`( _STRING VARCHAR(25)) RETURNS varchar(50) CHARSET utf8mb4
DETERMINISTIC
BEGIN
DECLARE _myCRC integer;
DECLARE _ord INTEGER;
DECLARE _n Integer;
DECLARE _m Integer;
DECLARE _strlend Integer;
SET _myCRC := x'FFFF';
SET _n := 1;
SET _strlend := LENGTH(_STRING) ;
loop_crc: LOOP
IF _n > _strlend THEN
LEAVE loop_crc;
END IF;
SET _ord := ORD(SUBSTRING(_STRING, _n, 1) );
SET _myCRC := _myCRC ^ _ord;
SET _m := 0;
loop_bit: LOOP
IF _m = 8 THEN
LEAVE loop_bit;
END IF;
IF (_myCRC & x'0001') = x'0001' THEN
SET _myCRC := (_myCRC >> 1) ^ x'A001';
ELSE
SET _myCRC := _myCRC >> 1;
END IF;
SET _m := _m + 1;
END LOOP;
SET _n := _n + 1;
END LOOP;
return HEX(_myCRC);
END//
DELIMITER ;
查询SELECT CRC16("A");
Returns
CRC16("A")
707F
您可以在 https://crccalc.com/ 中查看结果，或者使用您自己在 java 或 C#
中的结果