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Base_convert changes

php.internals

Scott Dutton

7 years ago

Hi,

I have just put a pull request together to make some changes to base_convert, the changes are as follows:

1, Allow conversion of negative numbers (fixes https://bugs.php.net/bug.php?id=55393)
2, Raise a notice when passing in invalid chars as input, currently they are just silently ignored

Part of the negative number change causes a BC break due to needing to use a "zend_long" instead of a "zend_ulong" this breaks a number of tests, but allows negative numbers to be represented correctly.

The PR is here https://github.com/php/php-src/pull/3911/files

I look forward to hearing thoughts on this

Thanks

Scott

Nikita Popov

7 years ago

On Sun, Mar 10, 2019 at 1:29 PM Scott Dutton <scott@exussum.co.uk> wrote:

> Hi,
>
> I have just put a pull request together to make some changes to
> base_convert, the changes are as follows:
>
> 1, Allow conversion of negative numbers (fixes
> https://bugs.php.net/bug.php?id=55393)
> 2, Raise a notice when passing in invalid chars as input, currently they
> are just silently ignored
>
> Part of the negative number change causes a BC break due to needing to use
> a "zend_long" instead of a "zend_ulong" this breaks a number of tests, but
> allows negative numbers to be represented correctly.
>
> The PR is here https://github.com/php/php-src/pull/3911/files
>
> I look forward to hearing thoughts on this
>
> Thanks
>
> Scott

Both changes sound reasonable to me. Could you show some examples where the
output is going to change due to the zend_ulong->zend_long switch?

Nikita

Scott Dutton

7 years ago

On 11.03.2019 10:51, Nikita Popov wrote:

>
> Both changes sound reasonable to me. Could you show some examples
> where the
> output is going to change due to the zend_ulong->zend_long switch?
>
> Nikita

Sure!

For example

var_dump(decbin(9223372036854775807));

would currently show

string(64)
"1000000000000000000000000000000000000000000000000000000000000000"

After these changes it would show

string(65)
"-000000000000000000000000000000000000000000000000000000000000000"

var_dump(decbin(9223372036854775806));

would be the same for both showing.

string(63)
"111111111111111111111111111111111111111111111111111111111111110"

As the code is reused for decbin etc all of the helper functions have a
similar effect.

Also userland code would look like this currently

$converted = base_convert($original, 2, 10);
if ($original < 0) {
$converted = - $converted;
}

So anyone who use coded around this will also break.

I have pushed some fixed suggested to the PR again all comments
welcome, my C is quite rusty so happy to change anything

Thanks

Marc

3 years ago

Hi,

I noticed a deprecation of passing invalid characters to bindec since
PHP 7.4 which is still deprecated and does not result in an error.

Haven't checked the other affected functions of this RFC.

https://3v4l.org/Bqj5B

Is anyone taking care to remove this in 9.0?

Thanks,

Marc