From: David Laight <David.Laight@ACULAB.COM>
To: "'Pali Rohár'" <pali.rohar@gmail.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Namjae Jeon <linkinjeon@gmail.com>,
"Gabriel Krisman Bertazi" <krisman@collabora.com>
Subject: RE: vfat: Broken case-insensitive support for UTF-8
Date: Mon, 20 Jan 2020 15:47:22 +0000 [thread overview]
Message-ID: <1a4c545dc7f14e33b7e59321a0aab868@AcuMS.aculab.com> (raw)
In-Reply-To: <20200120152009.5vbemgmvhke4qupq@pali>
From: Pali Rohár
> Sent: 20 January 2020 15:20
...
> This is not possible. There is 1:1 mapping between UTF-8 sequence and
> Unicode code point. wchar_t in kernel represent either one Unicode code
> point (limited up to U+FFFF in NLS framework functions) or 2bytes in
> UTF-16 sequence (only in utf8s_to_utf16s() and utf16s_to_utf8s()
> functions).
Unfortunately there is neither a 1:1 mapping of all possible byte sequences
to wchar_t (or unicode code points), nor a 1:1 mapping of all possible
wchar_t values to UTF-8.
Really both need to be defined - even for otherwise 'invalid' sequences.
Even the 16-bit values above 0xd000 can appear on their own in
windows filesystems (according to wikipedia).
It is all to easy to get sequences of values that cannot be converted
to/from UTF-8.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-01-20 15:48 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-19 22:14 vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-19 23:08 ` Al Viro
2020-01-19 23:33 ` Pali Rohár
2020-01-20 0:09 ` Al Viro
2020-01-20 11:19 ` Pali Rohár
2020-01-20 4:04 ` OGAWA Hirofumi
2020-01-20 7:30 ` Al Viro
2020-01-20 7:45 ` Al Viro
2020-01-20 8:07 ` oopsably broken case-insensitive support in ext4 and f2fs (Re: vfat: Broken case-insensitive support for UTF-8) Al Viro
2020-01-20 19:35 ` Al Viro
2020-01-24 4:29 ` Eric Biggers
2020-01-24 17:47 ` Linus Torvalds
2020-01-24 18:03 ` Jaegeuk Kim
2020-01-24 18:45 ` Eric Biggers
2020-01-20 11:04 ` vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-20 12:07 ` OGAWA Hirofumi
2020-01-20 21:40 ` Pali Rohár
2020-01-20 22:46 ` Al Viro
2020-01-20 23:57 ` Pali Rohár
2020-01-21 0:07 ` Al Viro
2020-01-21 20:34 ` Pali Rohár
2020-01-21 21:36 ` Al Viro
2020-01-21 22:14 ` Al Viro
2020-01-21 22:46 ` Pali Rohár
2020-01-26 23:08 ` Pali Rohár
2020-01-21 12:43 ` David Laight
2020-01-22 0:25 ` Gabriel Krisman Bertazi
2020-01-20 15:07 ` David Laight
2020-01-20 15:20 ` Pali Rohár
2020-01-20 15:47 ` David Laight [this message]
2020-01-20 16:12 ` Al Viro
2020-01-20 16:51 ` David Laight
2020-01-20 16:27 ` Pali Rohár
2020-01-20 16:43 ` David Laight
2020-01-20 16:56 ` Pali Rohár
2020-01-20 17:37 ` Theodore Y. Ts'o
2020-01-20 17:32 ` Theodore Y. Ts'o
2020-01-20 17:56 ` Pali Rohár
2020-01-21 3:52 ` OGAWA Hirofumi
2020-01-21 11:00 ` Pali Rohár
2020-01-21 12:26 ` OGAWA Hirofumi
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