rem: struct map_struct *buf,int offset,int n)
add: struct map_struct *buf,OFF_T offset,int n)
context: static void simple_send_token(int f,int token,			      struct map_struct *buf,int offset,int n){	if (n > 0) {		int l = 0;		while (l < n) {			int n1 = MIN(CHUNK_SIZE,n-l);			write_int(f,n1);			write_buf(f,map_ptr(buf,offset+l,n1),n1);			l += n1;		}	}	write_int(f,-(token+1));}