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Date: Tue, 20 Jan 2015 10:21:43 +0100
To: Xinchen Hui <xinchen.h@zend.com>
Cc: Dmitry Stogov <dmitry@zend.com>,
	PHP Internals <internals@lists.php.net>
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Message-ID: <20150120092146.E93615F8D3@mx.zeyon.net>
Subject: Re: [PHP-DEV] Re: Improvements to array.c code base
From: ben.coutu@zeyos.com (Benjamin Coutu)

Sorry, your right of course as not preserving keys only applies to numeric =
indices.=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 Coutu <be=
n.coutu@zeyos.com>=0ADate: Tue, 20 Jan 2015 10:13:04 +0100=0ASubject: Re: [=
PHP-DEV] Re: Improvements to array.c code base=0A=0A=0A=0AHey:=0A=0AOn Tue,=
 Jan 20, 2015 at 5:06 PM, Benjamin Coutu <ben.coutu@zeyos.com> wrote:=0A> H=
i,=0A>=0A> Regarding ARRAY_SLICE(..., preserve_keys=3Dfalse) my whole point=
 was that the check for non-numeric key inputs is not necessary if preserve=
_keys is false.=0A> It should basically be analogue to array_values(), but =
of course respecting the offset and length boundaries.=0AI am not sure I un=
derstood your point.=0A=0Aeven if preserve_keys is false, it still use stri=
ng key if origin is string key.=0A=0A=0A>=0A> One question regarding FAST_Z=
PP: Why is it not used more often, especially in the satndard libraries? Is=
 there some particular drawback? I'd like to understand.=0A=0Ahmm, https://=
wiki.php.net/rfc/fast_zpp :)=0A=0Athanks=0A>=0A> Thanks,=0A>=0A> Ben=0A>=0A=
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Original =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0A=
> From: Xinchen Hui <xinchen.h@zend.com>=0A> To: Benjamin Coutu <ben.coutu@=
zeyos.com>=0A> Date: Tue, 20 Jan 2015 09:53:38 +0100=0A> Subject: [PHP-DEV]=
 Re: Improvements to array.c code base=0A>=0A>=0A>=0A> Hey:=0A>=0A>=0A> On =
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/arr=
ay.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>> array_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>> Removing the check for packed inputs on line 2376 would improve perfo=
rmance if used on non-packed inputs with the default preserve_keys=3Dfalse.=
=0A> This is check for non-numeric key inputs=0A>=0A>> Furthermore, ZEND_HA=
SH_FOREACH_VAL should be used instead of ZEND_HASH_FOREACH_NUM_KEY_VAL on l=
ine 2379.=0A> yeah, I will fix it.=0A>> It also think range() should use FA=
ST_ZPP as it is a basic language feature (other languages even have extra o=
perators for it, e.g. [0..10])=0A>>=0A>> =3D=3D=3D RANGE(...) =3D=3D=3D=0A>=
>=0A>> range() always returns a numerically indexed array [0..count-1]. The=
 resulting array therefore should be constructed as a packed array (ZEND_HA=
SH_FILL_PACKED+ZEND_HASH_FILL_ADD instead of zend_hash_next_index_insert_ne=
w).=0A>>=0A>> =3D=3D=3D ARRAY_FILL(start_key=3D0, ...)=0A>>  =3D=3D=3D=0A>>=
=0A>> Just like with range(), array_fill() always returns a numerically ind=
exed array [0..count-1] if start_key is 0. In this special but very common =
case the resulting array can be constructed as a packed array (ZEND_HASH_FI=
LL_PACKED+ZEND_HASH_FILL_ADD instead of zend_hash_next_index_insert_new).=
=0A>> Another common case is for start_key to be 1. One could refine the pr=
oposed packed-array branch to just set the first bucket to undefined in thi=
s case.=0A>>=0A>> =3D=3D=3D COUNT(...) =3D=3D=3D=0A>>=0A>> count() is so ub=
iquitous! Giving it an opcode and making it part of the VM seams reasonable=
.=0A>>=0A>> Please let me know your thoughts.=0A> hmm, we currently do opti=
mization based on profile against some real=0A> life apps, like wordpress.=
=0A>=0A> range and array_fill etc doesn't used very common.. so I didn't lo=
ok into it..=0A>=0A> thanks for the advise, I will take a look .=0A>=0A> th=
anks=0A>>=0A>> Cheers,=0A>>=0A>> Ben=0A>>=0A>> --=0A>>=0A>> Benjamin Coutu=
=0A>> Zeyon Technologies Inc.=0A>> http://www.zeyos.com=0A>>=0A>