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To: <internals@lists.php.net>,
	"Dmitry Stogov" <dmitry@zend.com>
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Date: Mon, 23 Mar 2009 10:05:30 -0500
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Subject: Re: [PATCH] Bug #45877: LONG_MAX/MIN array key as string/int
From: php_lists@realplain.com ("Matt Wilmas")

Hi Dmitry,

----- Original Message -----
From: "Dmitry Stogov"
Sent: Monday, March 23, 2009

> Hi Matt,
>
> Matt Wilmas wrote:
>> Hi Dmitry,
>>
>> While updating my version (more below), I noticed another problem that I 
>> overlooked before with your leading zero check: "-0" is being treated as 
>> numeric.
>
> Yeah. Thank you for catching this. It should be fixed.
>
>> ----- Original Message -----
>> From: "Dmitry Stogov"
>> Sent: Friday, March 20, 2009
>>
>>> Hi Matt,
>>>
>>> I ran you version but it looked little bit slower (I checked it with 
>>> callgrind). So I kept the current CVS version. Anyway, it is not a big 
>>> problem to change it after RC.
>>
>> Yeah, after I sent that message, I noticed other times were strange 
>> (bench.php, etc.), so it looks like I was getting compiler weirdness with 
>> that code layout...  And of course looking at the code, there shouldn't 
>> have been anything faster about it, though it was shorter, which you 
>> confirmed with callgrind.
>>
>> Anyway, my updated version seems good, still smaller, and should do 
>> better with callgrind. :-)  On 32-bit, the first digit of a 10 digit 
>> number can be checked which avoids having "2x overflow" on "5000000000", 
>> etc. that I pointed out with your original code.  (No problem on 64-bit.) 
>> Also made the terminating null check be last again since it's least 
>> likely to fail...
>>
>> http://realplain.com/php/handle_numeric.txt
>> OLD: http://realplain.com/php/handle_numeric-v1.txt
>
> It looks like now your version must be better.
> Are you sure that it can't miss overflow? Can it be proved?

Well, as far as I can tell, it can be proved. :-)  On 32-bit, <= 9 digits is 
obviously OK, and if there's 10, it's only used if it starts with a 1 or 2. 
Overflow with 2500000000 is caught by the </> 0 check, and 5000000000, which 
the </> 0 check in your first version missed, won't be used since we can 
tell from the first digit that it wouldn't fit.  On 64-bit, LONG_MAX starts 
with a 9, and there wouldn't be an overflow missed by the </> 0 check until 
ULONG_MAX, which is another digit longer, and would be skipped by the 
"numbers too long" check.

> Thanks. Dmitry.

- Matt