[U-Boot] [U-Boot, v0, 07/20] vsprintf.c: add wide string (%ls) support

[Rob Clark]

On Tue, Aug 8, 2017 at 6:03 PM, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> On 08/04/2017 09:31 PM, Rob Clark wrote:
>> This is convenient for efi_loader which deals a lot with utf16.
>>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>
> Please, put this patch together with
> [PATCH] vsprintf.c: add GUID printing
> https://patchwork.ozlabs.org/patch/798362/
> and
> [PATCH v0 06/20] common: add some utf16 handling helpers
> https://patchwork.ozlabs.org/patch/797968/
> into a separate patch series.
>
> These three patches can be reviewed independently of the efi_loader
> patches and probably will not be integrated via the efi-next tree.

I'll resend these as a separate patchset, and just not in next
revision of efi_loader patchset that it is a dependency

>> ---
>>  lib/vsprintf.c | 30 ++++++++++++++++++++++++++++--
>>  1 file changed, 28 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
>> index 874a2951f7..0c40f852ce 100644
>> --- a/lib/vsprintf.c
>> +++ b/lib/vsprintf.c
>> @@ -17,6 +17,7 @@
>>  #include <linux/ctype.h>
>>
>>  #include <common.h>
>> +#include <charset.h>
>>
>>  #include <div64.h>
>>  #define noinline __attribute__((noinline))
>> @@ -270,6 +271,26 @@ static char *string(char *buf, char *end, char *s, int field_width,
>>       return buf;
>>  }
>>
>> +static char *string16(char *buf, char *end, u16 *s, int field_width,
>> +             int precision, int flags)
>> +{
>> +     u16 *str = s ? s : L"<NULL>";
> Please, do not use the L-notation here as it requires -fshort-wchar.
> As we currently cannot switch the complete project to C11 you cannot use
> the u-notation either.

current plan was to either switch whole project to -fshort-wchar or
c11 and rework these patches (as well as a few patches in the
efi_loader patchset).  (In the c11 case, I'm not sure what we'll use
as the fmt string, since afaict that isn't specified.  We could use %S
although that seems to be a deprecated way to do %ls, or something
different like %A, I guess)..

how far are we from c11?  If there is stuff I can do to help let me
know.  If feasible, I'd rather do that first rather than have a bunch
of stuff in vsprintf and elsewhere that needs to be cleaned up later
after the switch.

>
>> +     int len = utf16_strnlen(str, precision);
>> +     u8 utf8[len * MAX_UTF8_PER_UTF16];
>
> Didn't you forget 1 byte for \0 here?
>
> This is what strlnlen does:
>
> The strnlen() function returns the number of characters in the string
> pointed to by s, **excluding** the terminating null byte ('\0'), but at
> most maxlen.
>
> I would expect the exclusion of the terminating null word by an
> utf16_strnlen function.

you are right, but fixing the wrong problem.. the code is definitely
wrong since length of a utf16 string != length of a utf8 string, and
we don't need to append a null terminator.. so my logic below using
'len' is wrong.  I'll fix that in the next version.

>> +     int i;
>> +
>> +     *utf16_to_utf8(utf8, str, len) = '\0';
>> +
>> +     if (!(flags & LEFT))
>> +             while (len < field_width--)
>> +                     ADDCH(buf, ' ');
>> +     for (i = 0; i < len; ++i)
>> +             ADDCH(buf, utf8[i]);
>> +     while (len < field_width--)
>> +             ADDCH(buf, ' ');
>> +     return buf;
>> +}
>> +
>>  #ifdef CONFIG_CMD_NET
>>  static const char hex_asc[] = "0123456789abcdef";
>>  #define hex_asc_lo(x)        hex_asc[((x) & 0x0f)]
>> @@ -528,8 +549,13 @@ repeat:
>>                       continue;
>>
>>               case 's':
>> -                     str = string(str, end, va_arg(args, char *),
>> -                                  field_width, precision, flags);
>> +                     if (qualifier == 'l') {
>
> %ls refers to wchar with implementation dependent width in the C standard.
> There is no qualifier for 16-bit wchar. Couldn't we use %us here in
> reference to the u-notation ( u'MyString' ). This would leave the path
> open for a standard compliant '%ls'.

hmm, yeah, that is a clever idea, and I like it better than %A or %S..
so if we go the c11 route I'll do that.  The c11 committee should have
thought of that ;-)

BR,
-R

> Best regards
>
> Heinrich
>
>> +                             str = string16(str, end, va_arg(args, u16 *),
>> +                                            field_width, precision, flags);
>> +                     } else {
>> +                             str = string(str, end, va_arg(args, char *),
>> +                                          field_width, precision, flags);
>> +                     }
>>                       continue;
>>
>>               case 'p':
>>