Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:80863
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain zeyos.com designates 109.70.220.166 as permitted sender)
Date: Tue, 20 Jan 2015 10:06:20 +0100
To: Xinchen Hui <xinchen.h@zend.com>
Cc: Dmitry Stogov <dmitry@zend.com>,
	PHP Internals <internals@lists.php.net>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset="UTF-8"
Message-ID: <20150120090623.19AB15F8D3@mx.zeyon.net>
Subject: Re: [PHP-DEV] Re: Improvements to array.c code base
From: ben.coutu@zeyos.com (Benjamin Coutu)

Hi,=0A=0ARegarding ARRAY_SLICE(..., preserve_keys=3Dfalse) my whole point w=
as that the check for non-numeric key inputs is not necessary if preserve_k=
eys is false.=0AIt should basically be analogue to array_values(), but of c=
ourse respecting the offset and length boundaries.=0A=0AOne question regard=
ing FAST_ZPP: Why is it not used more often, especially in the satndard lib=
raries? Is there some particular drawback? I'd like to understand.=0A=0ATha=
nks,=0A=0ABen=0A=0A=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Original =3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=0AFrom: Xinchen Hui <xinchen.h@zend.com>=0ATo: Benjamin Cou=
tu <ben.coutu@zeyos.com>=0ADate: Tue, 20 Jan 2015 09:53:38 +0100=0ASubject:=
 [PHP-DEV] Re: Improvements to array.c code base=0A=0A=0A=0AHey:=0A=0A=0AOn=
 Tue, Jan 20, 2015 at 4:30 PM, Benjamin Coutu <ben.coutu@zeyos.com> wrote:=
=0A> Hi Dmitry,=0A>=0A> I was doing some code review of ext/standard/array.=
c and have recognized some potential for a few performance improvements:=0A=
>=0A> =3D=3D=3D ARRAY_SLICE(..., preserve_keys=3Dfalse) =3D=3D=3D=0A>=0A> a=
rray_slice() can always construct a packed array if preserve_keys is false,=
 restricting it to inputs with packed flag does not make much sense.=0A> Re=
moving the check for packed inputs on line 2376 would improve performance i=
f used on non-packed inputs with the default preserve_keys=3Dfalse.=0AThis =
is check for non-numeric key inputs=0A=0A> Furthermore, ZEND_HASH_FOREACH_V=
AL should be used instead of ZEND_HASH_FOREACH_NUM_KEY_VAL on line 2379.=0A=
yeah, I will fix it.=0A> It also think range() should use FAST_ZPP as it is=
 a basic language feature (other languages even have extra operators for it=
, e.g. [0..10])=0A>=0A> =3D=3D=3D RANGE(...) =3D=3D=3D=0A>=0A> range() alwa=
ys returns a numerically indexed array [0..count-1]. The resulting array th=
erefore should be constructed as a packed array (ZEND_HASH_FILL_PACKED+ZEND=
_HASH_FILL_ADD instead of zend_hash_next_index_insert_new).=0A>=0A> =3D=3D=
=3D ARRAY_FILL(start_key=3D0, ...)=0A>  =3D=3D=3D=0A>=0A> Just like with ra=
nge(), array_fill() always returns a numerically indexed array [0..count-1]=
 if start_key is 0. In this special but very common case the resulting arra=
y can be constructed as a packed array (ZEND_HASH_FILL_PACKED+ZEND_HASH_FIL=
L_ADD instead of zend_hash_next_index_insert_new).=0A> Another common case =
is for start_key to be 1. One could refine the proposed packed-array branch=
 to just set the first bucket to undefined in this case.=0A>=0A> =3D=3D=3D =
COUNT(...) =3D=3D=3D=0A>=0A> count() is so ubiquitous! Giving it an opcode =
and making it part of the VM seams reasonable.=0A>=0A> Please let me know y=
our thoughts.=0Ahmm, we currently do optimization based on profile against =
some real=0Alife apps, like wordpress.=0A=0Arange and array_fill etc doesn'=
t used very common.. so I didn't look into it..=0A=0Athanks for the advise,=
 I will take a look .=0A=0Athanks=0A>=0A> Cheers,=0A>=0A> Ben=0A>=0A> --=0A=
>=0A> Benjamin Coutu=0A> Zeyon Technologies Inc.=0A> http://www.zeyos.com=
=0A>