/*this is the CRC function */

/* you have to pass the buf to this function or make it a global 
variable  */ 

   	unsigned long crce( )  
   	{
   	long k,q,pol;
   	unsigned long crc;
   	
	crc = 0;
   	pol=0x104c11db7;  
// I picked this polynomial but you can pick another one
   	
   	for(q=0;q<8*4*sizeof(long);q++)
   	{
   	k=crc&(1<<31);
   	crc <<= 1;
   	if(buf[q/32]&(1<<(31-q%32)))
   	crc|=1;
   	if(k) crc^=pol;
   	}
 
   	return crc;
   	
   	} /* End of CRC function */

//  oh, do not for get to add a prototype for the function