[U-Boot] [PATCH 1/1] efi_loader: MAX_UTF8_PER_UTF16 = 3

[Heinrich Schuchardt]

On 10/09/2017 08:43 PM, Alexander Graf wrote:
> 
> 
>> Am 09.10.2017 um 20:39 schrieb Heinrich Schuchardt <xypron.glpk at gmx.de>:
>>
>> A code point encoded by one UTF-16 symbol is converted to a
>> maximum of three UTF-8 symbols.
>>
>> 0xffff could be encoded as 0xef 0xbf 0xbf.
>> The first byte carries four bits, the second and third byte
>> carry six bits each.
>>
>> A code point encoded by two UTF-16 symbols is converted to four
>> UTF-8 symbols.
> 
> Yes, so why do you set it to 3?

The constant is not bytes per code point but bytes per UTF-16.

4 / 2 = 2 < 3

Cheers

Heinrich

> 
> Please also explain what exactly this actually fixes :).
> 
> 
> Alex
> 
>>
>> Fixes: 78178bb0c9d lib: add some utf16 handling helpers
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>> The code is only used by efi_loader.
>> So this patch should go via efi-next.
>> ---
>> include/charset.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/charset.h b/include/charset.h
>> index 9c2866bbe6..2f7f7eacc9 100644
>> --- a/include/charset.h
>> +++ b/include/charset.h
>> @@ -9,7 +9,7 @@
>> #ifndef __CHARSET_H_
>> #define __CHARSET_H_
>>
>> -#define MAX_UTF8_PER_UTF16 4
>> +#define MAX_UTF8_PER_UTF16 3
>>
>> /**
>>  * utf16_strlen() - Get the length of an utf16 string
>> @@ -52,7 +52,7 @@ uint16_t *utf16_strdup(const uint16_t *s);
>>  * Converts 'size' characters of the utf16 string 'src' to utf8
>>  * written to the 'dest' buffer.
>>  *
>> - * NOTE that a single utf16 character can generate up to 4 utf8
>> + * NOTE that a single utf16 character can generate up to 3 utf8
>>  * characters.  See MAX_UTF8_PER_UTF16.
>>  *
>>  * @dest   the destination buffer to write the utf8 characters
>> -- 
>> 2.14.1
>>
>