Bug #54973 [Com]: SimpleXML casts intergers wrong.
Edit report at https://bugs.php.net/bug.php?id=54973&edit=1
ID: 54973
Comment by: kaplan@php.net
Reported by: bphelpsen at gmail dot com
Summary: SimpleXML casts intergers wrong.
Status: Analyzed
Type: Bug
Package: SimpleXML related
Operating System: Linux
PHP Version: 5.3.6
Block user comment: N
Private report: N
New Comment:
The referenced pull request (#213) has two tests to verify the fix for this bug
(when and if ready). Please don't forget to use them when commiting the fix.
Previous Comments:
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[2011-06-03 11:55:06] cataphract@php.net
I remember seeing this before. The problem is that the Zend engine, when doing the add operation,
converts any objects it finds to ints. The simplexml extension is merely doing what it's asked,
i.e., convert the value of the object to int.
The solution must be either
a) making the Zend Engine default the conversion to a double
b) making the Zend Engine try both a double and an int and compare the two results
c) making the Zend Engine convert the object to a string instead and then convert the string using
the usual means (that is, is_numeric_string)
d) change the API so that cast_object can be told to convert the object to either an int or a
double, sort of like is_numeric_string
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[2011-06-02 22:14:14] dtajchreber@php.net
This looks like a bug... SimpleXML's cast_object handler doesn't check for
overflow when trying to convert a node value to a
long. $xml->value goes through Zend's add_function and gets passed to
zendi_convert_scalar_to_number which calls SimpleXML's
cast_object handler because $xml->number is an object. It then gets chopped into
LONG_MAX by strtol. An overflow check could
fix this... but it might break some BC....
[1] http://lxr.php.net/xref/PHP_5_3/Zend/zend_operators.c#758
[2] http://lxr.php.net/xref/PHP_5_3/ext/simplexml/simplexml.c#1722
[3] http://lxr.php.net/xref/PHP_5_3/Zend/zend_operators.c#355
[4] http://lxr.php.net/xref/PHP_5_3/Zend/zend_operators.c#768
[5] http://www.gnu.org/s/hello/manual/libc/Parsing-of-Integers.html
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[2011-06-02 20:05:07] bphelpsen at gmail dot com
Then why do I get different results when I run this code:
<?php echo "214748364800" / 1024 / 1024 / 1024; ?>
than when I run the example code. Shouldn't they return the same value?
Here is an example, with the same results as my local test:
http://codepad.org/KICl3xHw
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[2011-06-02 20:00:54] iliaa@php.net
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php
This has nothing to do with SimpleXML, but rather the fact that a numeric string
in PHP by default would converted to an integer.
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[2011-06-01 22:18:27] bphelpsen at gmail dot com
Description:
------------
When an XML node value is an integer SimpleXML always casts it to an int, even if its a float or
double.
Test script:
---------------
<?php
$xml =
simplexml_load_string("<xml><number>214748364800</number></xml>");
echo $xml->number . "\n"; // the proper number
$int = $xml->number / 1024 / 1024 / 1024; // initial cast to an int causes problems
echo $int . "\n";
$double = (double) $xml->number / 1024 / 1024 / 1024; // hard cast to a double fixes it
echo $double . "\n";
?>
Expected result:
----------------
214748364800
200
200
Actual result:
--------------
214748364800
1.9999999990687
200
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=54973&edit=1
Thread (10 messages)