Re: [Vala] [Fwd: Re: Fwd: uchar and uint8. Same? Different?]

[pancake <pancake youterm com>]

For unicode characters you have 'unichar'. uchar doesnt applies to
multibyte characters.

I have been informed that the non8bit char architectures are:

   * Digital Equipment Corporation PDP-6/10
   * IBM 701/704/709/7090/7094
   * UNIVAC 1103/1103A/1105/1100/2200,

The uchar in those boxes are 6 and 9 bit size.

Weird but true :)

So, child! take care when compiling Vala programs on PDP and VAX!

pancake wrote:
> ------------------------------------------------------------------------
>
> Subject:
> Re: [Vala] Fwd: uchar and uint8. Same? Different?
> From:
> bb <bblochl arcor de>
> Date:
> Thu, 18 Feb 2010 09:23:14 +0100
> To:
> pancake <pancake youterm com>
>
> To:
> pancake <pancake youterm com>
>
>
> pancake schrieb:
> > Begin forwarded message:
> >
> > > From: pancake <pancake youterm com>
> > > Date: February 18, 2010 1:38:12 AM GMT+01:00
> > > To: Sandino Flores Moreno <tigrux gmail com>
> > > Subject: Re: [Vala] uchar and uint8. Same? Different?
> >
> > > This vapi looks wrong. Didn't [] implies a _length variable with no 
> > > ccodes?
> > >
> > > Those two types are the same in practice but not in theory. A uint8 
> > > is 8 bit size for sure, but uchar do not specifies the size.
> > >
> > > This should depend on the C compiler and platform. I don't know any 
> > > that uchar is != 8, but this doesn't means they exist.
> > >
> > > On Feb 17, 2010, at 10:03 PM, Sandino Flores Moreno 
> > > <tigrux gmail com> wrote:
> > >
> > > > Hello.
> > > >
> > > > I noticed that gstreamer has this declaration:
> > > >
> > > > GstBuffer {
> > > > uint8 *data;
> > > > }
> > > >
> > > > However, the corresponding .vapi has
> > > > class Gst.buffer {
> > > > uchar[] data;
> > > > }
> > > >
> > > > I know uchar and uint8 are the same in C.
> > > > And, apparently for vala too.
> > > >
> > > > So, the question is:
> > > >
> > > > Can we assume uint8 is the same than uchar in vala?
> > > > _______________________________________________
> > > > Vala-list mailing list
> > > > Vala-list gnome org
> > > > http://mail.gnome.org/mailman/listinfo/vala-list
> >
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> >   
>
> I do not know if the following might help. Anyway here is some 
> explanation:
>
> UTF-8 (8-bit UCS/Unicode Transformation Format) is a /variable-length/ 
> character encoding!
>
> First one has to remember that ASCII originally only wa a 7 bit 
> character set. UTF8 is backwards compatible with 7 bit ASCII only!
>
> But ASCII  was extended to 8 bit with the rise of the IBM-PC. 
> Therefore UCS characters U+0000 to U+007F (ASCII) are encoded simply 
> as bytes 0x00 to 0x7F (ASCII compatibility). This means that files and 
> strings which contain only 7-bit ASCII characters have the same 
> encoding under both ASCII and UTF-8.
>
> U-00000000 -- U-0000007F : 0/xxxxxxx/
>
> But the extendet code ASCII is reprensented with numbers (in 
> hexadecimal) 0x00 to 0xFF (0 to 255) and there the problem will begin. 
> If it is greater than 127 then you need to split it into two characters.
> UTF-8 encoded characters may theoretically be up to six bytes long, 
> however 16-bit BMP characters are only up to three bytes long, where 
> the bytes 0xFE and 0xFF are never used in the UTF-8 encoding. The 
> encoding beyond ASCII 7F is different:
>
> /The Copyright Character in /
>
> /ASCII = 0xA9 = 1010 1001/
>
> /compares to /
>
> /UTF8 = 0xC2 0xA9 = 11000010 10101001/
>
> I do not plan to write a complete tutorial here, but I was involved 
> with the problem in the past. May be some C-code from my past 
> (transfer it to vala) might help:
>
> char *ascii_to_utf8(unsigned char c)
> {
>        unsigned char *out;
>               if(c < 128)
>        {
>                out = (char *)calloc(2, sizeof(char));
>                out[0] = c;
>                out[1] = '\0';
>        }
>        else
>        {
>                out = (char *)calloc(3, sizeof(char));
>                out[1] = (c >> 6) | 0xC0;
>                out[0] = (c & 0x3F) | 0x80;
>                out[2] = '\0';
>        }
>               return out;
> }
>
> Might be a good idea to add it to the vala examples?
>
> One more example from http://www.cl.cam.ac.uk/~mgk25/unicode.html 
> <http://www.cl.cam.ac.uk/%7Emgk25/unicode.html> :
>
> #include <stdio.h>
> #include <locale.h>
>
> int main()
> {
>    if (!setlocale(LC_CTYPE, "")) {
>      fprintf(stderr, "Can't set the specified locale! "
>              "Check LANG, LC_CTYPE, LC_ALL.\n");
>      return 1;
>    }
>    printf("%ls\n", L"Schöne Grüße");
>    return 0;
> }
>
> There are some special german characters, so one might see the problem 
> of encoding. The comment from the given source:
>
> "Call this program with the locale setting LANG=de_DE and the output 
> will be in ISO 8859-1. Call it with LANG=de_DE.UTF-8 and the output 
> will be in UTF-8. The %ls format specifier in printf calls wcsrtombs 
> in order to convert the wide character argument string into the 
> locale-dependent multi-byte encoding."
>
> Some more settings for experiments:
>
> en_US English - United States
>
> ru_RU Russian for Russia
>
> zh_TW Traditional Chinese for Taiwan
>
> etc.
>
>
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