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Diffstat (limited to '')
-rw-r--r-- | lib/c32width.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/lib/c32width.c b/lib/c32width.c new file mode 100644 index 0000000..7edf008 --- /dev/null +++ b/lib/c32width.c @@ -0,0 +1,102 @@ +/* Determine the number of screen columns needed for a 32-bit wide character. + Copyright (C) 2020-2024 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/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2023. */ + +#include <config.h> + +#define IN_C32WIDTH +/* Specification. */ +#include <uchar.h> + +#include <wchar.h> + +#ifdef __CYGWIN__ +# include <cygwin/version.h> +#endif + +#if GNULIB_defined_mbstate_t +# include "streq.h" +#endif + +#include "localcharset.h" + +#if GL_CHAR32_T_IS_UNICODE +# include "lc-charset-unicode.h" +#endif + +#include "uniwidth.h" + +#if _GL_WCHAR_T_IS_UCS4 && !GNULIB_defined_mbstate_t +_GL_EXTERN_INLINE +#endif +int +c32width (char32_t wc) +{ + /* The char32_t encoding of a multibyte character is defined by the way + mbrtoc32() is defined. */ + +#if GNULIB_defined_mbstate_t /* AIX, IRIX */ + /* mbrtoc32() is defined on top of mbtowc() for the non-UTF-8 locales + and directly for the UTF-8 locales. */ + const char *encoding = locale_charset (); + if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0)) + return uc_width (wc, encoding); + else + return wcwidth (wc); + +#elif HAVE_WORKING_MBRTOC32 /* glibc, Android */ + /* mbrtoc32() is essentially defined by the system libc. */ + +# if _GL_WCHAR_T_IS_UCS4 + /* The char32_t encoding of a multibyte character is known to be the same as + the wchar_t encoding. */ + return wcwidth (wc); +# else + /* The char32_t encoding of a multibyte character is known to be UCS-4, + different from the wchar_t encoding. */ + return uc_width (wc, locale_charset ()); +# endif + +#elif _GL_SMALL_WCHAR_T /* Cygwin, mingw, MSVC */ + /* The wchar_t encoding is UTF-16. + The char32_t encoding is UCS-4. */ + +# if defined __CYGWIN__ && CYGWIN_VERSION_DLL_MAJOR >= 1007 && 0 + /* As an extension to POSIX, the wcwidth() function of Cygwin >= 1.7 + supports also wc arguments outside the Unicode BMP, that is, outside + the 'wchar_t' range. See + <https://www.cygwin.com/cgit/newlib-cygwin/commit/?id=098a75dc51caa98f369d98a9809d773bc45329aa>. + But the resulting values for these characters are not of good quality. */ + return wcwidth (wc); +# else + if (wc == (wchar_t) wc) + /* wc is in the range for the wcwidth function. */ + return wcwidth (wc); + else + return uc_width (wc, locale_charset ()); +# endif + +#else /* macOS, FreeBSD, NetBSD, OpenBSD, HP-UX, Solaris, Minix, Android */ + /* char32_t and wchar_t are equivalent. */ + static_assert (sizeof (char32_t) == sizeof (wchar_t)); + +# if GL_CHAR32_T_IS_UNICODE && GL_CHAR32_T_VS_WCHAR_T_NEEDS_CONVERSION + return uc_width (wc, locale_charset ()); +# endif + return wcwidth (wc); +#endif +} |