[U-Boot] [PATCH] vsprintf.c: add wide string (%ls) support

[Rob Clark]

On Tue, Aug 1, 2017 at 10:22 PM, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> On 07/31/2017 02:42 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>
>> ---
>>  lib/vsprintf.c | 39 +++++++++++++++++++++++++++++++++++++--
>>  1 file changed, 37 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
>> index 874a2951f7..84e157ecb1 100644
>> --- a/lib/vsprintf.c
>> +++ b/lib/vsprintf.c
>> @@ -270,6 +270,35 @@ static char *string(char *buf, char *end, char *s, int field_width,
>>       return buf;
>>  }
>>
>> +static size_t strnlen16(const u16* s, size_t count)
>> +{
>> +     const u16 *sc;
>> +
>> +     for (sc = s; count-- && *sc; ++sc)
>> +             /* nothing */;
>> +     return sc - s;
>> +}
>> +
>> +static char *string16(char *buf, char *end, u16 *s, int field_width,
>> +             int precision, int flags)
>> +{
>> +     int len, i;
>> +
>> +     if (s == NULL)
>> +             s = L"<NULL>";
>
> The L notation creates a wchar_t string. The width of wchar_t depends on
> gcc compiler flag -fshort-wchar.
>
> vsprintf.c is not compiled with -fshort-wchar. So change this to
>
> const u16 null[] = { '<', 'N', 'U', 'L', 'L', '>', 0};
> s = null;

oh, I have another patch that adds -fshort-wchar globally.. which I
probably should have split out and sent with this.

The problem is we cannot mix objects using short-wchar and ones that
don't without a compiler warning.  Travis would complain a lot more
but I guess BOOTEFI_HELLO is not normally enabled.

With addition of efi_bootmgr.c we really want to be able to use
L"string" to be u16.. and I don't think u-boot has any good reason to
use 32b wchar.

But maybe for this code I should use wchar_t instead of u16.

BR,
-R

>> +
>> +     len = strnlen16(s, precision);
>> +
>> +     if (!(flags & LEFT))
>> +             while (len < field_width--)
>> +                     ADDCH(buf, ' ');
>> +     for (i = 0; i < len; ++i)
>> +             ADDCH(buf, *s++);
>> +     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 +557,14 @@ repeat:
>>                       continue;
>>
>>               case 's':
>> -                     str = string(str, end, va_arg(args, char *),
>> -                                  field_width, precision, flags);
>> +                     if (qualifier == 'l') {
>
> According to ISO 9899:1999 %ls is used to indicate a wchar_t string,
> which may be u32 * or u16 * depending on GCC flag -fshort-wchar.
>
> Wouldn't it make sense to use some other notation, e.g. %S, to indicate
> that we explicitly mean u16 *?
>
> Please, add a comment into the code indicating why we need u16 * support
> referring to the UEFI spec.
>
> 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':
>>
>