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Date: Sat, 27 Jul 2024 15:26:09 +0200
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Subject: Re: [PHP-DEV] [RFC] Working With Substrings
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To: Rowan Tommins <rowan.collins@gmail.com>, internals@lists.php.net,
 Thomas Hruska <thruska@cubiclesoft.com>
References: <e352423f-b740-07c9-2c4a-996112e17bbe@cubiclesoft.com>
 <92c4514f-70e3-75c9-7084-9e29641e25e7@gmail.com>
 <7e86a2d2-b971-592c-64e3-e86c13b5be80@cubiclesoft.com>
 <E963ED74-0404-4A5D-9811-8D1E662F764A@gmail.com>
In-Reply-To: <E963ED74-0404-4A5D-9811-8D1E662F764A@gmail.com>
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From: cmbecker69@gmx.de ("Christoph M. Becker")

On 15.02.2023 at 06:18, Rowan Tommins wrote:

> On 15 February 2023 02:35:42 GMT, Thomas Hruska <thruska@cubiclesoft.com=
> wrote:
>
>> On 2/14/2023 2:02 PM, Rowan Tommins wrote:
>>
>> I thought about that but didn't know how well it would be received nor,=
 perhaps more importantly, the direction it should take (i.e. a formal Zen=
d type in the engine, extending the existing zend_string type, a class, so=
me combination, or something else entirely).  All of the more advanced opt=
ions I came up with would have required some code changes to the PHP sourc=
e itself with a new data type being the most involved and probably the mos=
t controversial.
>
> My instinct was that it could just be a built-in class, with an internal=
 pointer to a zend_string that's completely invisible to userland. Somethi=
ng like how the SimpleXML and DOM objects just point into a libxml parse r=
esult.
>
> Then to add to existing functions requires changing an argument type fro=
m string to string|Buffer, rather than adding new arguments.
>
> No change to the type system needed, internally or externally, just some=
 code to unwrap the pointer. But perhaps I'm being naive and oversimplifyi=
ng, as I don't have a deep understanding of the engine.
>
>> I'm not entirely sure what the next step here should be.  Should I go r=
esearch the above, or go back and develop/test and then propose something =
concrete in an OO direction and gather feedback at that point, or should w=
e hash it out a bit more here on the list to get a more specific direction=
 to go in?
>
> Well, those were just my thoughts; maybe someone else will come along sh=
ortly with a very different take.

I'm very late on this discussion, but I think it is an interesting
topic, and maybe <https://github.com/cmb69/php-stringbuilder>, which I
had written long ago just to check some assumptions, can serve as POC.
It is certainly possible to have such a string buffer class without
having to patch the engine; it could even be made available as PECL
extension (first).

Note that this StringBuilder uses `smart_str`s[1] what might be a good
idea or not.  But certainly you could use some other internal handling;
interoperability with `zend_string`s[2] requires to copy the char arrays
in most cases anyway, since these have a fixed length, and if these
copies are reduced to a minimum (i.e. the new class has enough
flexibility to work without casting to and from string), that should be
bearable.

Not sure if that would work for the "gd imageexportpixels() and
imageimportpixels()" RFC[3], but it might be worth investigating.

[1]
<https://www.phpinternalsbook.com/php7/internal_types/strings/smart_str.ht=
ml>
[2]
<https://www.phpinternalsbook.com/php7/internal_types/strings/zend_strings=
.html>
[3] <https://wiki.php.net/rfc/gd_image_export_import_pixels>

Cheers,
Christoph