Slight refactoring to avoid GCC signed overflow warnings. [ci skip]
Slight refactoring to avoid GCC signed overflow warnings. [ci skip]

Couldn't occur since length is 24 bits but GCC couldn't figure that out.

webmaster128/botan,randombit/botan,webmaster128/botan,randombit/botan,randombit/botan,webmaster128/botan,webmaster128/botan,webmaster128/botan,randombit/botan,randombit/botan