Force PHP integer overflow

So I solved the problem, and discovered a lot about PHP (at least in the way it handles Integer overflow).

1) It completely depended on a cross between which platform the machine was running on, which version of PHP, whether or not it had Suhosin Hardened PHP running, and how many bits it was compiled for (32 or 64). 6 machines behaved the way I expected (which was actually wrong, at least wrong according to their documentation) and 3 machines behaved in a way I still can't explain, and 3 machines behaved according to what the intval command says it does in the documentation.

2) Intval is supposed to return PHP_INT_MAX when int > PHP_INT_MAX (not int & 0xffffffff), but this only happens on some versions of PHP4 and PHP5. Different versions of PHP return different values when int > PHP_INT_MAX.

3) The following code can return 3 different results (see 1):

<?php
echo "Php max int: ".PHP_INT_MAX."\n";
echo "The Val: ".(-1580033017 + -2072974554)."\n";
echo "Intval of the val: ".intval(-3653007571)."\n";
echo "And 0xffffffff of the val: ".(-3653007571 & 0xffffffff)."\n";
?>

It can return (which appears to be right for Intval but wrong for & 0xffffff)

Php max int: 2147483647
The Val: -3653007571
Intval of the val: -2147483648
And of the val: -2147483648

And it can return (which contradicts the PHP documentation for intval):

Php max int: 2147483647
The Val: -3653007571
Intval of the val: -641959725
And of the val: -641959725

And on 64 Bit machines it returns (which is correct):

Php max int: 2147483647
The Val: -3653007571
Intval of the val: -3653007571
And of the val: -641959725

Solution

Anyhow, I needed a solution that would work on all these platforms, and not be dependent upon quirks of a particular version of PHP compiled with a particular Max int. Thus I cam up with the following cross-PHP thirtyTwoBitIntval function:

function thirtyTwoBitIntval($value)
{
    if ($value < -2147483648)
    {
        return -(-($value) & 0xffffffff);
    }
    elseif ($value > 2147483647)
    {
        return ($value & 0xffffffff);
    }
    return $value;
}

Comment

I do think the designers of PHP should have said an Int is a 32 Bit Int no matter whether it is running on a 32 or 64 or 128 bit machine (like the DotNet CLR for example), and didn't randomly upconvert it to a float depending on the number of Bits that PHP is compiler under.

If you want to have 100% working solution for 32-bit intval both on 32 and 64 bit platforms, then I suggest you to use the following solution:

function intval32bits($value)
{
    $value = ($value & 0xFFFFFFFF);

    if ($value & 0x80000000)
        $value = -((~$value & 0xFFFFFFFF) + 1);

    return $value;
}

Internally, PHP uses an "integer" type for most numbers. However, these only go so far: if you add a large integer to a large integer, PHP will see that the result is too big to fit into a normal integer and will assign it to a floating-point number. Floating-point numbers (floats) themselves only go so high, however, and there's a point around the sixteen-digit mark where PHP will just lose the plot entirely.

There is an option to use arbitrary-precision mathematics which supports numbers of any size and precision, represented as strings. See more here: http://us2.php.net/bc