Re: [PATCH] gconv: Do not emit spurious NUL character in ISO-2022-JP-3 (bug 28524)

[Florian Weimer <fweimer@redhat.com>]

* Никита Попов:

> From d8321b3b4399a6e1999bd0ebd1466f6235dc5630 Mon Sep 17 00:00:00 2001
> From: Nikita Popov <npv1310@gmail.com>
> Date: Tue, 2 Nov 2021 13:21:42 +0500
> Subject: [PATCH] gconv: Do not emit spurious NUL character in ISO-2022-JP-3
>  (bug 28524)
>
> Bugfix 27256 has introduced another issue:
> In conversion from ISO-2022-JP-3 encoding, it is possible
> to force iconv to emit extra NUL character on internal state reset.
> To do this, it is sufficient to feed iconv with escape sequence
> which switches active character set.
> The simplified check 'data->__statep->__count != ASCII_set'
> introduced by the aforementioned bugfix picks that case and
> behaves as if '\0' character has been queued thus emitting it.
>
> To eliminate this issue, these steps are taken:
> * Restore original condition
> '(data->__statep->__count & ~7) != ASCII_set'.
> It is necessary since bits 0-2 may contain
> number of buffered input characters.
> * Check that queued character is not NUL.
> Similar step is taken for main conversion loop.
>
> Bundled test case follows following logic:
> * Try to convert ISO-2022-JP-3 escape sequence
> switching active character set
> * Reset internal state by providing NULL as input buffer
> * Ensure that nothing has been converted.
>
> Signed-off-by: Nikita Popov <npv1310@gmail.com>

Thanks, applied.

Florian