Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:73733
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.128.174 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <CAPhkiZytT+-8NSF9BNUXnOa-tsfN1a-Fjbj0tOoxB1hPnuqqnQ@mail.gmail.com>
References: <CAPwsocErQTJ=2S2Yn5PhWgCha8T_GVkJSz0XkTN9Qz3OPDTVyA@mail.gmail.com>
	<1397744009.2829.3212.camel@guybrush>
	<CAPhkiZze6mtk8_+tcibWG7Z3KYCaJT-OxEb8BKBsKrBK6Kw2Tw@mail.gmail.com>
	<1397747255.2829.3225.camel@guybrush>
	<CAPhkiZytT+-8NSF9BNUXnOa-tsfN1a-Fjbj0tOoxB1hPnuqqnQ@mail.gmail.com>
Date: Fri, 18 Apr 2014 06:11:09 +0800
Message-ID: <CAHMUw2EAr33Ceq1UL9gT2OYUoSo8gqdP0Aah+5O=fVxgYBdbVw@mail.gmail.com>
To: Andrey Andreev <narf@devilix.net>
Cc: =?UTF-8?Q?Johannes_Schl=C3=BCter?= <johannes@schlueters.de>, 
	Leigh <leight@gmail.com>, "internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=bcaec52e635d6ac10b04f7444f7f
Subject: Re: [PHP-DEV] Negative string offsets
From: tjerk.meesters@gmail.com (Tjerk Meesters)

--bcaec52e635d6ac10b04f7444f7f
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Hi,


On Thu, Apr 17, 2014 at 11:22 PM, Andrey Andreev <narf@devilix.net> wrote:

> Hi,
>
> On Thu, Apr 17, 2014 at 6:07 PM, Johannes Schl=C3=BCter
> <johannes@schlueters.de> wrote:
> > 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.
> >
> >         $sep =3D strrpos($filename, ".");
> >         if ($sep !=3D=3D false) {
> >             $ext =3D substr($filename, $sep + 1);
> >         }
> >
> > is clear and concise, two fcalls, can be understood even after years an=
d
> > the new programmer easily.
> >
> > This is the most concise form I came up using this new offset:
> >
> >         $ext =3D '';
> >         $pos =3D -1;
> >         do {
> >             $ext =3D $filename[$pos].$ext;
> >         } while ($filename[--$pos] !=3D '.');
> >
> > 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 $pos accordingly and iterate from strlen() to 0.
> > Also this form does more comparisons and way more allocations and is (i=
n
> > my opinion) way harder to understand.
> >
> > Maye I didn't see a simple form ...
> >
> > johannes
>
> For most filename extensions:
>
>     if ($filename[-4] =3D=3D=3D '.')
>     {
>         $ext =3D substr($filename, -3);
>     }
>

I know that this was just an example of the use-case, but to get a file
extension you would typically do:

    $ext =3D pathinfo($filename, PATHINFO_EXTENSION);

;-)


> Or, checking if a path has a slash at the end:
>
>     if ($path[-1] =3D=3D=3D '/') { ... }
>
> I'm talking strictly about validation here (and yes, the filename
> example won't work with i.e. .jpeg, but would satisfy a large amount
> of use cases), comparing stuff on the fly.
>
> Cheers,
> Andrey.
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>


--=20
--
Tjerk

--bcaec52e635d6ac10b04f7444f7f--