Why does 0x8FFFFFF equal 128MB?

Question

I sometimes see code like this:

int length = 0x8FFFFFF; //128MB
byte buf = new byte[length];

It does not make much sense to me as:

0x8FFFFFF = 150,994,943
128MB = 128 * 1024 * 1024 byte = 134,217,728 byte

These two number does not equal. What am I missing here?

Thanks,

Answer 1

Well, 0x7FFFFFF = 134217727, so 128MB should be 0x8000000

Answer 2

Someone previously had a 7 there but changed it to a 8 in order to avoid an off-by-one error, but forgot to change the rest to 0.