For example a list is encoded as

	l        u32
	[l]item  itemType

on decode len is read from data stream and for rest of data len(data) is
checked to be < l*sizeof(item).

However since l is u32 and sizeof(item) is just number the result of `l
* sizeof(item)` has also u32 type. However it could overflow e.g. for

	l		= 0x20000000
	sizeof(item)	= 8

with the l*sizeof(item) being = u32(0)	(exactly zero) -> oops.

Avoid the problem by doing all checking arithmetics with u64 ints.