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純C的 CRC16(和 C# CRC16 CCITT TABLE 範例運算結果相同)運算 – jashliao部落格

2021/12/25

純C的 CRC16(和 C# CRC16 CCITT TABLE 範例運算結果相同)運算

資料來源:https://github.com/jash-git/C_CRC16

#include
#include
/*
Figure 2.7 ¡V C Language implementation of the CRC calculation
*/
unsigned int calcrc16( unsigned char * dataP, int n )
{
   unsigned char i, j; // Byte counter, bit counter
   unsigned int crc16; // calculation
   crc16 = 0x0000; // PRESET value
   for (i = 0; i < n; i++) // check each Byte in the array
   {
       crc16 ^= *dataP++;
       for (j = 0; j < 8; j++) // test each bit in the Byte
       {
           if(crc16 & 0x0001 )
           {
               crc16 >>= 1;
               crc16 ^= 0x8408; // POLYNOMIAL x^16 + x^12 + x^5 + 1
           }
           else
           {
               crc16 >>= 1;
           }
       }
   }
   return( crc16 ); // returns calculated crc (16 bits)
}
int main()
{
unsigned char data[6];
//string input = “00 06 80 01 00 03”;
data[0]=00;
data[1]=06;
data[2]=16*8;
data[3]=01;
data[4]=00;
data[5]=02;
unsigned int CRC16= calcrc16( data, 6 );
printf(“%d\n%X”,CRC16,CRC16);
return 0;
}