CRC 算法

crc16 算法

unsigned shortcrc16 (unsigned char *pD, int len)
{
   static unsigned short poly[2]={0, 0xa001};
   unsigned short crc = 0xffff;
   unsigned char ds;
   int i,j;

   for(j=len; j>0; j--)
   {
    unsigned char ds = *pD++;
    for(i=0; i<8; i++)
     {
        crc = (crc >> 1) ^ poly[(crc ^ ds ) & 1];
        ds = ds >> 1;
     }
   }

  return crc;
}