towlower.cpp File Reference

#include <corecrt_internal.h>
#include <ctype.h>
#include <locale.h>

Include dependency graph for towlower.cpp:

Go to the source code of this file.

Functions
wint_t __cdecl	_towlower_l (wint_t const c, _locale_t const plocinfo)
wint_t __cdecl	towlower (wint_t c)

Function Documentation

_towlower_l()

wint_t __cdecl _towlower_l	(	wint_t const	c,
		_locale_t const	plocinfo
	)

Definition at line 28 of file towlower.cpp.

{
    if (c == WEOF)
    {
        return c;
    }
 
    _LocaleUpdate _loc_update(plocinfo);
    auto const locinfo = _loc_update.GetLocaleT()->locinfo;
 
    if (locinfo->_public._locale_lc_codepage == CP_UTF8)
    {
        // For 128 <= c < 256, the tolower map would consider the wide character as it is in UTF-8, not UTF-16.
        // Below 128, UTF-8 and UTF-16 have the same encodings, so we can use the table.
        if (c < 128)
        {
            return _towlower_fast_internal(static_cast<unsigned char>(c), _loc_update.GetLocaleT());
        }
    }
    else
    {
        // For 128 <= c < 256, the tolower map will consider the wide character as it would be in the current narrow code page,
        // which can lead to unexpected behavior. This behavior is maintained for backwards compatibility.
        if (c < 256)
        {
            return _towlower_fast_internal(static_cast<unsigned char>(c), _loc_update.GetLocaleT());
        }
 
        if (locinfo->locale_name[LC_CTYPE] == nullptr)
        {
            // If the locale is C, then the only characters that would be transformed are <256
            // and have been processed already.
            return c;
        }
    }
 
    wint_t widechar;
    if (0 == __acrt_LCMapStringW(
                locinfo->locale_name[LC_CTYPE],
                LCMAP_LOWERCASE,
                (LPCWSTR)&c,
                1,
                (LPWSTR)&widechar,
                1))
    {
        return c;
    }
 
    return widechar;
}

Referenced by towlower().

towlower()

wint_t __cdecl towlower

(

wint_t

c

)

Definition at line 99 of file towlower.cpp.

{
 
    return _towlower_l(c, nullptr);
}