Re: string and wide string usage

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 7 Mar 2013 06:20:05 -0800 (PST), ytomino wrote:

> On Thursday, March 7, 2013 8:12:01 PM UTC+9, Ali Bendriss wrote:
>> I've got some problem with some string in example:
>> a base 64 encoded string
>> V2luZG93c8KgNyBQcm9mZXNzaW9ubmVsIE4=
>> wich decode to 'Windows\xa07 Professionnel N' in utf-8
>> every thing is working if I feed directly the database, but if want to 
>> apply Ada.Characters.Handling.To_Lower on the string before feeding the 
>> database postgres is not happy 
>> 'ERROR:  invalid byte sequence for encoding "UTF8": 0xe2 0xa0 0x37'
>> it's not really a big deal, but I would like to understand where the 
>> problem is. Do I have to use wide string ?
> 
> Because functions in Ada.Characters.Handling take not UTF-8 but Latin-1.
> You have to
> 1. convert UTF-8 String to Wide_Wide_String, process UTF-32 and restore it to UTF-8.
>   (Ada.Characters.Conversion also take Latin-1. You have to use GNAT.Encode_String/Decode_String or Ada.Strings.UTF_Encoding for converting.)
> 2. search a external library to process UTF-8 directly.

Provided the base 64 encodes an UTF-8 string, which you wanted to convert
to lower case UTF-8 string using the Unicode lower case mapping, then you
can use

   function To_Lowercase (Value : String) return String;

from

http://www.dmitry-kazakov.de/ada/strings_edit.htm#7.6

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de