This prevents out of array reads. An alternative solution would be
to check the index but this would require several checks in the
inner loops
Yet another alternative would be to change the index reset logic
but this likely would introduce a difference to the binary decoder
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This code relies on the result wrapping as for unsigned
values, and the sign is not used. Thus an unsigned type
is proper here.
Signed-off-by: Mans Rullgard <mans@mansr.com>