Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:24997
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <010601c6b169$225b9eb0$0201a8c0@pc1>
To: <internals@lists.php.net>
References: <00c601c6b095$a1a2e220$0201a8c0@pc1>
Date: Thu, 27 Jul 2006 05:40:52 -0500
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] dec*(), *dec(), base_convert() and negative numbers
From: php_lists@realplain.com ("Matt W")

Hi again,

I realize I might not get any answer about updating these little ol'
functions :-/, but it'd be nice to hear something one way or the other so I
can submit an acceptable patch with correct behavior.

After thinking about it more, are negative numbers even "officially
supported" with the dec[bin|hex|oct] functions?  You won't get anything
close to the original back with *dec(dec*(-123)).

Since base_convert() uses the number's absolute value, I'm thinking the only
reason for using "unsigned long" for the dec*() functions is to handle cases
where a PHP double is between LONG_MAX and ULONG_MAX.  If so, I think
absolute value can be used everywhere.

Or again, should I update the functions to correctly accept and return
negative values?  But I'm not sure if negative bin/hex/oct strings are
desired (semantically).

Thanks for any simple guidance!


Matt


----- Original Message -----
From: "Matt W"
Sent: Wednesday, July 26, 2006


> Hi all,
>
> I was just updating the dec[bin|hex|oct] functions to convert numbers >=
> 2^32 since the [bin|hex|oct]dec counterparts were updated way back in PHP
> 4.1.
>
> My question is if negative numbers should be handled any differently.  Now
> negative longs are converted to unsigned which gives a weird result for
> regular users IMO.  The *dec() functions ignore negative strings.  Because
> of the way base_convert() works, if you pass a negative number (gets
> converted to string), the result will be from the absolute value instead
of
> what you get with dec*().
>
> *) Should the dec*() functions continue to convert negative longs to
> unsigned and use absolute value for doubles?
>
> *) Should absolute value always be used, like with base_convert()?
>
> *) Should everything be changed to support negative numbers going both
> directions (to or from base)?
>
>
> Thanks,
> Matt