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Date: Wed, 16 Jul 2014 07:12:13 +0900
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To: Andrea Faulds <ajf@ajf.me>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] intdiv()
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

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Hi Andrea,

On Tue, Jul 15, 2014 at 11:10 AM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:

> On Tue, Jul 15, 2014 at 9:14 AM, Andrea Faulds <ajf@ajf.me> wrote:
>
>> PHP currently lacks a way to do integer division. You can floor or int
>> cast a floating-point division, but beyond 53-bits that produces the wro=
ng
>> result:
>>
>> $ sapi/cli/php -r 'var_dump((int)(PHP_INT_MAX / 3));'
>> int(3074457345618258432)
>>
>> Furthermore, using a floating-point division isn=E2=80=99t really a prop=
er way to
>> do it; it=E2=80=99s a workaround for a lack of language support for a qu=
ite basic
>> operation. This RFC proposes a function for integer division, intdiv(). =
It
>> would work properly with 64-bit values:
>>
>> $ sapi/cli/php -r 'var_dump(intdiv(PHP_INT_MAX, 3));'
>> int(3074457345618258602)
>>
>
> We have GMP object from 5.6 and we can do
>
> [yohgaki@dev php-5.6]$ ./php-bin -r '$i =3D gmp_init('21342'); $a =3D $i =
/ 3;
> var_dump($a);'
> object(GMP)#2 (1) {
>   ["num"]=3D>
>   string(4) "7114"
> }
> [yohgaki@dev php-5.6]$ ./php-bin -r '$i =3D gmp_init('21342'); $a =3D $i =
*
> 99999999; var_dump($a);'
> object(GMP)#2 (1) {
>   ["num"]=3D>
>   string(13) "2134199978658"
> }
>
> IMHO, GMP is the choice when precise computation is needed as it could be
> any number.
> Native integer type is much faster for sure. Question is do we really nee=
d
> it?
>

If we are going to have integer arithmetics, it may be better to have full
set of operators/functions

https://bugs.php.net/bug.php?id=3D30701

Regards,

--
Yasuo Ohgaki
yohgaki@ohgaki.net

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