[parted-devel] wcslwidth and the width of non ascii characters

[Brian C. Lane]

On Fri, Dec 08, 2017 at 02:30:00PM -0500, Phil Susi wrote:
> So this crash was being caused by parted/table.c calling wcswidth() as
> part of how it calculates how much whitespace to pad the column out
> with.  It seems that wcswidth returns -1 if it finds a non printable
> character, which causes the padding to overflow the buffer and corrupt
> memory.  I can fix that by switching to wcslen(), but then the columns
> are no longer lined up properly.
> 
> It appears this is because these Kanji(?) characters are actually extra
> wide, despite supposedly being a fixed width font.  It seems as though
> wcswidth() knows this and takes it into account, but it blows up on non
> printable characters.
> 
> Any idea how to get the correct width even with non printable characters
> present?

Maybe declare unprintable characters a lost cause? Use wcswidth unless
it returns -1 and then fall back to wcswidth? So usually the columns
will align, except in rare (hopefully!) cases when they won't, but at
least it won't crash.

-- 
Brian C. Lane (PST8PDT)