Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:105090
Date: Fri, 05 Apr 2019 09:26:30 +0200
To: PHP Internals <internals@lists.php.net>
Cc: Dmitry Stogov <dmitry@zend.com>,
	Nikita Popov <nikita.ppv@gmail.com>
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Message-ID: <20190405072630.E2A025FB14@mx.zeyos.com>
Subject: Optimize zend_string equality check with hash key
From: ben.coutu@zeyos.com (Benjamin Coutu)

Hello,=0A=0AI was surprised to find out that equality checks on zend_string=
 do not take advantage of the fact that in many cases we have a hash key av=
ailable that can be utilized in a quick bailout path without having to reso=
rt to a costly `memcmp` on the value.=0A=0AI recommend to modify `zend_stri=
ng_equal_content` like so:=0A=0Astatic zend_always_inline zend_bool zend_st=
ring_equal_content(zend_string *s1, zend_string *s2)=0A{=0A  if (ZSTR_LEN(s=
1) !=3D ZSTR_LEN(s2)) {=0A    return 0;=0A  }=0A=0A  if (ZSTR_H(s1) && ZSTR=
_H(s1) !=3D ZSTR_H(s2)) {=0A    return 0;=0A  }=0A=0A  return zend_string_e=
qual_val(s1, s2);=0A}=0A=0AThoughts?=0A=0A-- =0A=0ABenjamin Coutu=0Aben.cou=
tu@zeyos.com