Power of two

[dasJ]

Hello,

this is not a bug or something like that, but I think, you can optimize your code.
https://github.com/lxndr/vtf/blob/master/vtf.cpp#L88
The method in this file isPowerOfTwo has a loop and can not recognize sizes > 32768.
The faster way is a simple macro:

define IS_POWER_OF_TWO(t) ( t > 0 && !(t & (t − 1)))

The simple reason for this is that powers of two look in binary like this:
1: 0001
2: 0010
4: 0100
8: 1000
Everytime, there is exacly one bit set.

• Janne

[lxndr]

Thank you, dasJ! This seems to be the best way to do it.