求C++大神和VB大神帮小弟我把转换下代码:c++ to vb

/*-------------------------------------------*/
// Summary：判断校验位是否正确
// Parameter:
//    (char*)buf -> 报文段(在0ah与0dh之间的片段)
// Return:  SUM_OK(0): The sum check is succeed.
//    SUM_ERR(1):The sum check is fail.
/*-------------------------------------------*/
int CSocketManager::SumCheck(unsigned char *buf) 
{
    unsigned char sum = 0;
    unsigned char rx_sum;
    int    i;
    int    len = strlen((char*)buf);

    rx_sum = ((buf[len-2] << 4) & 0xf0) + (buf[len-1] & 0x0f);
    for( i = 0 ; i < len-2 ; i++)
    {
        sum += buf[i];
    }
    if(sum != rx_sum)    return SUM_ERR;

    return    SUM_OK;
}