rem: uint32 _checksum_(const uchar* buf, int32 size)
add: _checksum_(const uchar* buf, int32 size)
context: uint32 _checksum_(const uchar* buf, int32 size){	uint32 sum = 0;	uint32 temp = 0;	while (size > 3) {#if defined(__INTEL__)		sum += B_SWAP_INT32(*(int*)buf);#else		sum += *(int*)buf;#endif		buf += 4;		size -= 4;	}	while (size > 0) {		temp = (temp << 8) + *buf++;		size -= 1;		sum += temp;	}	return sum;}