74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
/* Determine the number of screen columns needed for a character.
|
|
Copyright (C) 2006-2007, 2010-2023 Free Software Foundation, Inc.
|
|
|
|
This file is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This file is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
#include <config.h>
|
|
|
|
/* Specification. */
|
|
#include <wchar.h>
|
|
|
|
/* Get iswprint. */
|
|
#include <wctype.h>
|
|
|
|
#include "localcharset.h"
|
|
#include "streq.h"
|
|
#include "uniwidth.h"
|
|
|
|
/* Returns 1 if the current locale is an UTF-8 locale, 0 otherwise. */
|
|
static inline int
|
|
is_locale_utf8 (void)
|
|
{
|
|
const char *encoding = locale_charset ();
|
|
return STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0);
|
|
}
|
|
|
|
#if GNULIB_WCHAR_SINGLE_LOCALE
|
|
/* When we know that the locale does not change, provide a speedup by
|
|
caching the value of is_locale_utf8. */
|
|
static int cached_is_locale_utf8 = -1;
|
|
static inline int
|
|
is_locale_utf8_cached (void)
|
|
{
|
|
if (cached_is_locale_utf8 < 0)
|
|
cached_is_locale_utf8 = is_locale_utf8 ();
|
|
return cached_is_locale_utf8;
|
|
}
|
|
#else
|
|
/* By default, don't make assumptions, hence no caching. */
|
|
# define is_locale_utf8_cached is_locale_utf8
|
|
#endif
|
|
|
|
int
|
|
wcwidth (wchar_t wc)
|
|
#undef wcwidth
|
|
{
|
|
/* In UTF-8 locales, use a Unicode aware width function. */
|
|
if (is_locale_utf8_cached ())
|
|
{
|
|
/* We assume that in a UTF-8 locale, a wide character is the same as a
|
|
Unicode character. */
|
|
return uc_width (wc, "UTF-8");
|
|
}
|
|
else
|
|
{
|
|
/* Otherwise, fall back to the system's wcwidth function. */
|
|
#if HAVE_WCWIDTH
|
|
return wcwidth (wc);
|
|
#else
|
|
return wc == 0 ? 0 : iswprint (wc) ? 1 : -1;
|
|
#endif
|
|
}
|
|
}
|