nette/utils — pull request #47 by JanTvrdik (2014-12-14 21:20:40+00:00)
Title: Strings::substring(): avoid calculating string length unless necessary

Minor optimization. I was originally wanted to call `self::length` only when `mb_substr` is not available but as it turned out, `mb_substr` also does not handles this well in PHP < 5.4.8.