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From: "H. Peter Anvin" <hpa@zytor.com>
To: Adam Borowski <kilobyte@angband.pl>
Cc: Roy Franz <roy.franz@linaro.org>,
	linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
	matt.fleming@intel.com, leif.lindholm@linaro.org,
	msalter@redhat.com
Subject: Re: [PATCH 09/17] Move unicode to ASCII conversion to shared function.
Date: Wed, 18 Sep 2013 22:46:39 -0500	[thread overview]
Message-ID: <523A739F.9050103@zytor.com> (raw)
In-Reply-To: <20130919034406.GA26385@angband.pl>

On 09/18/2013 10:44 PM, Adam Borowski wrote:
> 
> In fact, these days it's 8-bit encodings that are more likely to be Unicode
> than 16-bit ones: UTF-8 is ubiquitous, while you usually get UCS2 at most.
> In either case, though, we have here is a 7-bit charset encoded as either
> 8-bit or 16-bit units.  What this function does is blindly truncating upper
> byte.  The supported payload is in both cases ASCII.
> 
> I'd thus rename the function to what it already does: truncating u16 to u8,
> and adjust comments accordingly.
> 
> Replacing values above 126 with a token character like '?' would be good
> too: that'd avoid producing corrupted characters and/or random ASCII chars.
> 
> Your commit only moves things around, so it might be out of scope for now,
> but I wonder: what if the kernel actually supported Unicode here?  Few
> cmdline arguments take values where non-ASCII makes sense, but at least some
> do: for example, a Russian guy is not unlikely to name subvolumes using
> cyrillic.  Supporting that would be easy (estimating the length then
> utf16s_to_utf8s()).  There's just one problem: which encoding to use, but
> these days, most distributions have either dropped non-UTF8 or hardly pay
> lip service, so we could get away with hard-coding UTF-8: those few who
> use ancient charsets can stick to ASCII.  Would this be ok?  If so, shout,
> I can code this if you don't care enough.
> 

We should, indeed, do proper conversion to UTF-8 here.

I also suspect we should assume the input is UTF-16 rather than UCS-2,
although that is a bit more exotic.

	-hpa


  reply	other threads:[~2013-09-19  3:47 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-17  4:11 [PATCH V4 00/17] ARM EFI stub common code Roy Franz
2013-09-17  4:11 ` [PATCH 01/17] EFI stub documentation updates Roy Franz
2013-09-17  4:11 ` [PATCH 02/17] Add proper definitions for some EFI function pointers Roy Franz
2013-09-17  4:11 ` [PATCH 03/17] Move common EFI stub code from x86 arch code to common location Roy Franz
2013-09-17  4:11 ` [PATCH 04/17] Add system table pointer argument to shared functions Roy Franz
2013-09-17  4:11 ` [PATCH 05/17] Rename memory allocation/free functions Roy Franz
2013-09-17  4:11 ` [PATCH 06/17] Enforce minimum alignment of 1 page on allocations Roy Franz
2013-09-17  4:11 ` [PATCH 07/17] Move relocate_kernel() to shared file Roy Franz
2013-09-17  4:11 ` [PATCH 08/17] Generalize relocate_kernel() for use by other architectures Roy Franz
2013-09-18 12:12   ` Matt Fleming
2013-09-18 16:31     ` Roy Franz
2013-09-17  4:11 ` [PATCH 09/17] Move unicode to ASCII conversion to shared function Roy Franz
2013-09-19  3:44   ` Adam Borowski
2013-09-19  3:46     ` H. Peter Anvin [this message]
2013-09-19  4:48     ` Roy Franz
2013-09-19 23:02       ` Adam Borowski
2013-09-20  9:30         ` Matt Fleming
2013-09-20  9:27       ` Matt Fleming
2013-09-20 15:00         ` H. Peter Anvin
2013-09-21 21:31           ` Roy Franz
2013-09-17  4:11 ` [PATCH 10/17] Rename __get_map() to efi_get_memory_map() Roy Franz
2013-09-17  4:11 ` [PATCH 11/17] generalize efi_get_memory_map() Roy Franz
2013-09-17  4:11 ` [PATCH 12/17] use efi_get_memory_map() to get final map for x86 Roy Franz
2013-09-17  4:11 ` [PATCH 13/17] Allow efi_free() to be called with size of 0, and do nothing in that case Roy Franz
2013-09-17  4:11 ` [PATCH 14/17] Generalize handle_ramdisks() and rename to handle_cmdline_files() Roy Franz
2013-09-17  4:11 ` [PATCH 15/17] Renames in handle_cmdline_files() to complete generalization Roy Franz
2013-09-17  4:11 ` [PATCH 16/17] Fix types in EFI calls to match EFI function definitions Roy Franz
2013-09-17  4:11 ` [PATCH 17/17] resolve warnings found on ARM compile Roy Franz
2013-09-18 13:21 ` [PATCH V4 00/17] ARM EFI stub common code Matt Fleming
2013-09-20 14:32 ` H. Peter Anvin

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