C++ CRC16校验和计算:哪一个是正确的?
目前我正在研究,它需要一个CRC校验和。我实现了三个功能,产生了不同的结果:C++ CRC16校验和计算:哪一个是正确的?,c++,checksum,crc,modbus,C++,Checksum,Crc,Modbus,目前我正在研究,它需要一个CRC校验和。我实现了三个功能,产生了不同的结果: CRC16_表:根据modbus手册第114页上的内容实施,这是一种查表方式,但我没有验证手册中提供的表 CRC16_modbus:基于modbus手册第112页实现,这是一种简单的方法 CRC16_来源:基于实现,并至少与具有相同结果 我的代码如下: #include <iostream> #include <iomanip> using namespace std; static unsi
#include <iostream>
#include <iomanip>
using namespace std;
static unsigned char auchCRCHi[] = {
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40
};
static char auchCRCLo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4,
0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD,
0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32, 0x36, 0xF6, 0xF7,
0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE,
0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3, 0xA2,
0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB,
0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0, 0x50, 0x90, 0x91,
0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88,
0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80,
0x40
};
unsigned short CRC16_table(char* message, int len)
{
unsigned char uchCRCHi = 0xFF;
unsigned char uchCRCLo = 0xFF;
unsigned uIndex;
while(len--)
{
uIndex = uchCRCHi ^ *message++;
uchCRCHi = uchCRCLo ^ auchCRCHi[uIndex];
uchCRCLo = auchCRCLo[uIndex];
}
return (((unsigned short)uchCRCHi << 8) | (unsigned short)uchCRCLo);
}
unsigned short CRC16_origin(char* message, int len)
{
const unsigned short generator = 0xA001;
unsigned short crc = 0;
for(int i = 0; i < len; ++i)
{
crc ^= (unsigned short)(message[i] << 8);
for(int b = 0; b < 8; ++b)
{
if((crc & 0x8000) != 0)
{
crc <<= 1;
crc ^= generator;
}
else
crc <<= 1;
}
}
return crc;
}
unsigned short CRC16_modbus(char* message, int len)
{
const unsigned short generator = 0xA001;
unsigned short crc = 0xFFFF;
for(int i = 0; i < len; ++i)
{
crc ^= (unsigned short)message[i];
for(int b = 0; b < 8; ++b)
{
if((crc & 1) != 0)
{
crc >>= 1;
crc ^= generator;
}
else
crc >>= 1;
}
}
return crc;
}
int main()
{
char message[] = {0x01, 0x06,0x00, 0x63, 0x04, 0x00};
int len = 6;
unsigned short temp1 = CRC16_table(message, len);
unsigned short temp2 = CRC16_origin(message, len);
unsigned short temp3 = CRC16_modbus(message, len);
cout<<hex<<temp1<<endl;
cout<<hex<<temp2<<endl;
cout<<hex<<temp3<<endl;
return 0;
}
#包括
#包括
使用名称空间std;
静态无符号字符AUCHCCHI[]={
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,
0x40、0x01、0xC0、0x80、0x41、0x00、0xC1、0x81、0x40、0x00、0xC1、0x81、0x40、0x01、0xC0,
0x80、0x41、0x01、0xC0、0x80、0x41、0x00、0xC1、0x81、0x40、0x00、0xC1、0x81、0x40、0x01,
0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,
0x40、0x01、0xC0、0x80、0x41、0x00、0xC1、0x81、0x40、0x01、0xC0、0x80、0x41、0x01、0xC0、,
0x80、0x41、0x00、0xC1、0x81、0x40、0x00、0xC1、0x81、0x40、0x01、0xC0、0x80、0x41、0x01,
0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,
0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,
0x80、0x41、0x01、0xC0、0x80、0x41、0x00、0xC1、0x81、0x40、0x00、0xC1、0x81、0x40、0x01,
0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,
0x40、0x01、0xC0、0x80、0x41、0x01、0xC0、0x80、0x41、0x00、0xC1、0x81、0x40、0x01、0xC0,
0x80、0x41、0x00、0xC1、0x81、0x40、0x00、0xC1、0x81、0x40、0x01、0xC0、0x80、0x41、0x01,
0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,
0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,
0x40
};
静态字符AUCHCRCO[]={
0x00、0xC0、0xC1、0x01、0xC3、0x03、0x02、0xC2、0xC6、0x06、0x07、0xC7、0x05、0xC5、0xC4,
0x04、0xCC、0x0C、0x0D、0xCD、0x0F、0xCF、0xCE、0x0E、0x0A、0xCA、0xCB、0x0B、0xC9、0x09、,
0x08、0xC8、0xD8、0x18、0x19、0xD9、0x1B、0xDB、0xDA、0x1A、0x1E、0xDE、0xDF、0x1F、0xDD、,
0x1D、0x1C、0xDC、0x14、0xD4、0xD5、0x15、0xD7、0x17、0x16、0xD6、0xD2、0x12、0x13、0xD3、,
0x11、0xD1、0xD0、0x10、0xF0、0x30、0x31、0xF1、0x33、0xF3、0xF2、0x32、0x36、0xF6、0xF7、,
0x37、0xF5、0x35、0x34、0xF4、0x3C、0xFC、0xFD、0x3D、0xFF、0x3F、0x3E、0xFE、0xFA、0x3A、,
0x3B、0xFB、0x39、0xF9、0xF8、0x38、0x28、0xE8、0xE9、0x29、0xEB、0x2B、0x2A、0xEA、0xEE、,
0x2E,0x2F,0xEF,0x2D,0xED,0xEC,0x2C,0xE4,0x24,0x25,0xE5,0x27,0xE7,0xE6,0x26,
0x22、0xE2、0xE3、0x23、0xE1、0x21、0x20、0xE0、0xA0、0x60、0x61、0xA1、0x63、0xA3、0xA2,
0x62、0x66、0xA6、0xA7、0x67、0xA5、0x65、0x64、0xA4、0x6C、0xAC、0xAD、0x6D、0xAF、0x6F、,
0x6E、0xAE、0xAA、0x6A、0x6B、0xAB、0x69、0xA9、0xA8、0x68、0x78、0xB8、0xB9、0x79、0xBB、,
0x7B、0x7A、0xBA、0xBE、0x7E、0x7F、0xBF、0x7D、0xBD、0xBC、0x7C、0xB4、0x74、0x75、0xB5、,
0x77、0xB7、0xB6、0x76、0x72、0xB2、0xB3、0x73、0xB1、0x71、0x70、0xB0、0x50、0x90、0x91,
0x51、0x93、0x53、0x52、0x92、0x96、0x56、0x57、0x97、0x55、0x95、0x94、0x54、0x9C、0x5C、,
0x5D、0x9D、0x5F、0x9F、0x9E、0x5E、0x5A、0x9A、0x9B、0x5B、0x99、0x59、0x58、0x98、0x88,
0x48、0x49、0x89、0x4B、0x8B、0x8A、0x4A、0x4E、0x8E、0x8F、0x4F、0x8D、0x4D、0x4C、0x8C、,
0x44、0x84、0x85、0x45、0x87、0x47、0x46、0x86、0x82、0x42、0x43、0x83、0x41、0x81、0x80,
0x40
};
无符号短CRC16_表(字符*消息,整数长度)
{
无符号字符uchCRCHi=0xFF;
无符号字符uchCRCLo=0xFF;
未签名的uIndex;
而(len--)
{
uIndex=uchCRCHi^*消息++;
uchCRCHi=uchCRCLo^auchcchi[uIndex];
uchCRCLo=auchcrco[uIndex];
}
返回(((无符号短)uchCRCHi
- Modbus使用初始值0xffff
- 您的第三个示例使用的初始值为零,在文盲示例中执行得很差
它们不会提供相同的结果。请坚持使用Modbus代码。除了其他答案外,我应该在函数中使用无符号字符*
作为第一个参数,而不是字符*
,因为当我将其转换为无符号短
时,如果它是字符*
,并且MSB是1,它将为t添加ff
他输入了高字节,这显然是错误的
谢谢大家!解决了!三种方法中的一种:
CRC16_table
是正确的,但仅在big-endian CPU上。在过去,基于表的方法是最快的方法,但它不能很好地在处理器之间进行移植
CRC16\u origin
使用了错误的种子值。它为某些内容计算CRC,但不计算modbus
CRC16\u modbus
正确且可移植
对于现代处理器,CRC16_表
和CRC16_modbus
方法之间的性能差异可能不值得考虑可移植性问题。分析一下并找出答案。在我的PC上,它们并驾齐驱,可以说是最简单、最便携的。在ARM或MSP430上,谁能说呢
实验性黑客代码:
#include <stdint.h>
#include <iostream>
#include <chrono>
uint16_t sizeeffect; // hack global to force execution of loops
static unsigned char auchCRCHi[] = {
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40
};
static unsigned char auchCRCLo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4,
0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD,
0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32, 0x36, 0xF6, 0xF7,
0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE,
0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3, 0xA2,
0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB,
0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0, 0x50, 0x90, 0x91,
0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88,
0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80,
0x40
};
unsigned short CRC16_table(char* message, int len)
{
unsigned char uchCRCHi = 0xFF;
unsigned char uchCRCLo = 0xFF;
unsigned uIndex;
while(len--)
{
uIndex = uchCRCHi ^ *message++;
uchCRCHi = uchCRCLo ^ auchCRCHi[uIndex];
uchCRCLo = auchCRCLo[uIndex];
}
return (((unsigned short)uchCRCHi << 8) | (unsigned short)uchCRCLo);
}
// CRC table I'm using for Wintell and PC linux
static const uint16_t lCRCTable[] =
{
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
};
// CRC table I'm using for Wintell and PC linux
uint16_t CRC16 (const uint8_t *datap, size_t len)
{
uint8_t loc;
uint16_t crc = 0xFFFF;
while (len--)
{
loc = *datap++ ^ crc;
crc >>= 8;
crc ^= lCRCTable[loc];
}
return crc;
}
unsigned short CRC16_modbus(const char* message, int len)
{
const unsigned short generator = 0xA001;
unsigned short crc = 0xFFFF;
for(int i = 0; i < len; ++i)
{
crc ^= (unsigned short)message[i];
for(int b = 0; b < 8; ++b)
{
if((crc & 1) != 0)
{
crc >>= 1;
crc ^= generator;
}
else
crc >>= 1;
}
}
return crc;
}
int main()
{
char message[] = "I am the very model of a modern major general.";
uint16_t a = CRC16((uint8_t *)message, sizeof(message));
uint16_t b = CRC16_modbus(message, sizeof(message));
uint16_t c = CRC16_table(message, sizeof(message));
if (a == b)
{
std::cout << "A-B Match"<< std::endl;
}
else
{
std::cout << a << std::endl;
std::cout << b << std::endl;
}
if (a == c)
{
std::cout << "A-C Match"<< std::endl;
}
else
{
std::cout << a << std::endl;
std::cout << c << std::endl;
}
int count = 10000000;
std::chrono::time_point<std::chrono::high_resolution_clock> start, end;
start = std::chrono::high_resolution_clock::now();
while (count--)
{
sizeeffect = CRC16((uint8_t *)message, sizeof(message));
}
end = std::chrono::high_resolution_clock::now();
std::cout << "Table took " << std::chrono::duration_cast<std::chrono::microseconds>(end-start).count() << "\n";
count = 10000000;
start = std::chrono::high_resolution_clock::now();
while (count--)
{
sizeeffect = CRC16((uint8_t *)message, sizeof(message));
}
end = std::chrono::high_resolution_clock::now();
std::cout << "Calc took " << std::chrono::duration_cast<std::chrono::microseconds>(end-start).count() << "\n";
}
这不是审查服务。如果您有特定问题,请参阅并提供一个。查找消息加预期校验和的规范示例,以找出哪一个是正确的CRC16_表方法与我用于modbus的CRC表类似,但在您知道您需要表方法的速度之前,请使用易于阅读和解析的方法bug.感谢@user4581301,然而,这两种方法(表一和modbus原始方法)有时甚至会产生不同的结果,例如,当“message[]={0x01,0x06,0x00,0x63,0x04,0x80}”时,它们是完全不同的。然而,当“message[]={0x0”时
A-B Match
5874
61974
Table took 900167
Calc took 892935