Re: [PATCH v12 04/10] utf8: teach same_encoding() alternative UTF encoding names

> On 16 Mar 2018, at 00:25, Eric Sunshine <sunshine@sunshineco.com> wrote:
> 
> On Thu, Mar 15, 2018 at 6:57 PM,  <lars.schneider@autodesk.com> wrote:
>> The function same_encoding() checked only for alternative UTF-8 encoding
>> names. Teach it to check for all kinds of alternative UTF encoding
>> names.
>> 
>> Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
>> ---
>> diff --git a/utf8.c b/utf8.c
>> @@ -401,11 +401,27 @@ void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width,
>> +static int same_utf_encoding(const char *src, const char *dst)
>> +{
>> +       if (istarts_with(src, "utf") && istarts_with(dst, "utf")) {
>> +               /* src[3] or dst[3] might be '\0' */
>> +               int i = (src[3] == '-' ? 4 : 3);
>> +               int j = (dst[3] == '-' ? 4 : 3);
>> +               return !strcasecmp(src+i, dst+j);
>> +       }
>> +       return 0;
>> +}
> 
> Alternate implementation without magic numbers:
> 
>    if (iskip_prefix(src, "utf", &src) &&
>        iskip_prefix(dst, "utf", &dst)) {
>        if (*src == '-')
>            src++;
>        if (*dst == '-')
>            dst++;
>        return !strcasecmp(src, dst);
>    }
>    return 0;
> 
> ... assuming you add an iskip_prefix() function (patterned after skip_prefix()).

>> int is_encoding_utf8(const char *name)
>> {
>>        if (!name)
>>                return 1;
>> -       if (!strcasecmp(name, "utf-8") || !strcasecmp(name, "utf8"))
>> +       if (same_utf_encoding("utf-8", name))
>>                return 1;
>>        return 0;
>> }
>> @@ -414,6 +430,8 @@ int same_encoding(const char *src, const char *dst)
>> {
>>        if (is_encoding_utf8(src) && is_encoding_utf8(dst))
>>                return 1;
>> +       if (same_utf_encoding(src, dst))
>> +               return 1;
>>        return !strcasecmp(src, dst);
>> }
> 
> This seems odd. I would have expected the newly-added generalized
> conditional to replace the original UTF-8-specific conditional, not
> supplement it. That is, shouldn't the entire function body be:
> 
>    if (same_utf_encoding(src, dst))
>        return 1;
>    return !strcasecmp(src, dst);