onKeyEvent(keycode,status_a,status_b)
{
if(keycode==1)
onKeyEvent_1(status_a,status_b)
else if(keycode==2)
onKeyEvent_2(status_a,status_b)
...
}

onKeyEvent_1(status_a,status_b)
{
if(status_a==1)
onKeyEvent_1_1(status_b)
else if(status_a==2)
onKeyEvent_1_2(status_b)
...
}

onKeyEvent_1_2(status_b)
...