diff options
Diffstat (limited to 'lib/wcwidth.c')
| -rw-r--r-- | lib/wcwidth.c | 54 |
1 files changed, 34 insertions, 20 deletions
diff --git a/lib/wcwidth.c b/lib/wcwidth.c index 1e5e87cb..f99a0a61 100644 --- a/lib/wcwidth.c +++ b/lib/wcwidth.c @@ -1,26 +1,17 @@ /* Determine the number of screen columns needed for a character. - Copyright (C) 2006-2007, 2010-2018 Free Software Foundation, Inc. + Copyright (C) 2006-2007, 2010-2022 Free Software Foundation, Inc. - This program is free software: you can redistribute it and/or - modify it under the terms of either: + 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. - * the GNU Lesser General Public License as published by the Free - Software Foundation; either version 3 of the License, or (at your - option) any later version. - - or - - * the GNU General Public License as published by the Free - Software Foundation; either version 2 of the License, or (at your - option) any later version. - - or both in parallel, as here. - This program is distributed in the hope that it will be useful, + 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 General Public License for more details. + GNU Lesser General Public License for more details. - You should have received a copy of the GNU General Public License + 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> @@ -35,17 +26,40 @@ #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. */ - const char *encoding = locale_charset (); - if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0 ,0)) + 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, encoding); + return uc_width (wc, "UTF-8"); } else { |