Re: [PATCH v6 1/4] libcpp: reject codepoints above 0x10FFFF

[Damien Guibouret <damien.guibouret@partition-saving.com>]

Le 19/06/2023 à 23:34, Jason Merrill a écrit :
> On 6/6/23 16:50, Ben Boeckel wrote:
>> Unicode does not support such values because they are unrepresentable in
>> UTF-16.
> 
> Pushed.
> 
>> libcpp/
>>
>>     * charset.cc: Reject encodings of codepoints above 0x10FFFF.
>>     UTF-16 does not support such codepoints and therefore all
>>     Unicode rejects such values.
>>
>> Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
>> ---
>>   libcpp/charset.cc | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/libcpp/charset.cc b/libcpp/charset.cc
>> index d7f323b2cd5..3b34d804cf1 100644
>> --- a/libcpp/charset.cc
>> +++ b/libcpp/charset.cc
>> @@ -1886,6 +1886,13 @@ cpp_valid_utf8_p (const char *buffer, size_t 
>> num_bytes)
>>         int err = one_utf8_to_cppchar (&iter, &bytesleft, &cp);
>>         if (err)
>>       return false;
>> +
>> +      /* Additionally, Unicode declares that all codepoints above 
>> 0010FFFF are
>> +     invalid because they cannot be represented in UTF-16.
>> +
>> +     Reject such values.*/
>> +      if (cp >= 0x10FFFF)
>> +    return false;
>>       }
>>     /* No problems encountered.  */
>>     return true;
> 

Hello,

I think the comparison should be ">" instead of ">=" as 0x10ffff seems a 
valid value (Unicode says value above 0x10ffff is invalid).
Other tests around same value in this file are using ">".

Regards,

Damien