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Date: Thu, 17 Apr 2014 17:07:34 +0200
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Subject: Re: [PHP-DEV] Negative string offsets
From: johannes@schlueters.de (Johannes =?ISO-8859-1?Q?Schl=FCter?=)

On Thu, 2014-04-17 at 17:18 +0300, Andrey Andreev wrote:
> For example, every time you need to check for a filename extension,
> last segment of a path, etc. When I need that, I always endup with
> substr(), strrchr() or explode(), end() ... both are suboptimal.

I don't see where this helps in that case.

        $sep = strrpos($filename, ".");
        if ($sep !== false) {
            $ext = substr($filename, $sep + 1);
        }

is clear and concise, two fcalls, can be understood even after years and
the new programmer easily.

This is the most concise form I came up using this new offset:

        $ext = '';
        $pos = -1;
        do {
            $ext = $filename[$pos].$ext;
        } while ($filename[--$pos] != '.');

While this form is bugged as it assumes that there is a . without
checking. For checking I'd have to use strlen(), but if i call strlen()
I can also initialize $pos accordingly and iterate from strlen() to 0.
Also this form does more comparisons and way more allocations and is (in
my opinion) way harder to understand.

Maye I didn't see a simple form ...

johannes