[vlc-devel] Checking for __STDC_ISO_10646__ in Qt4 module

[Juho Vähä-Herttua]

Hi,

The code with slight portability issues in customwidgets.cpp is as follows:

    if( qtk <= 0xff )
        /* VLC and X11 use lowercase whereas Qt uses uppercase */
#if defined( __STDC_ISO_10646__ ) || defined( _WIN32 ) || defined( __APPLE__ )
         i_vlck = towlower( qtk );
#else
# error FIXME
#endif
    else
    {
        ...

This means that towlower is only called for qtk values smaller or equal to 255. I wrote a small test to check for the functionality of towlower with these values:

#include <stdio.h>
#include <wctype.h>

#ifndef __STDC_ISO_10646__
#error FIXME
#endif

main(i,c) {
        for (i=0; i<256; i++) {
                c = (i >= 'A' && i <= 'Z') ? i+32 : i;
                if (towlower(i) != c) printf("mismatch: %d\n", i);
        }
}

The result of this test was that it compiled fine on a linux machine and didn't print any output. This means that only characters [A-Z] are changed to lower case by the standard compliant towlower function, even though with a quick look code points between 0xC0 and 0xDE (excluding 0x0xD7) should be changed as well.

To avoid any change in VLC functionality, I would therefore rewrite the original code as follows:

    if( qtk <= 0xff )
        /* VLC and X11 use lowercase whereas Qt uses uppercase */
         i_vlck = (i >= 'A' && i <= 'Z') ? qtk+32 : qtk;
    else
    {
        ...

Any objections?

It feels funny now that I wasted hours debating about this issue just to find that only ASCII characters were affected in the first place.


Juho



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