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Diffstat (limited to '')
-rw-r--r-- | src/wchar/wcsstrncpy.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/wchar/wcsstrncpy.c b/src/wchar/wcsstrncpy.c new file mode 100644 index 0000000..89dd7f7 --- /dev/null +++ b/src/wchar/wcsstrncpy.c @@ -0,0 +1,55 @@ +/** + * slibc — Yet another C library + * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <wchar.h> + + + +/** + * Copy a memory segment to another, non-overlapping, segment, + * stop when a NUL wide character or a specified substring is encountered. + * + * This is a slibc extension added for completeness. + * It is only available if GNU extensions are available. + * + * @param whither The destination memory segment. + * @param whence The source memory segment. + * @param str The substring, ignored if `NULL`. + * @param maxlen The maximum number of wide characters to copy. + * NOTE that if the resulting string at least this + * long, no NUL character will be written to `whither'. + * On the otherhand, if the resultnig string is + * shorter, `whither` will be filled with NUL characters + * until this amount of characters have been written. + * @return `NULL` if `str` was not encountered, otherwise + * the position of `str` translated to `whither`, + * that is, the address of `whither` plus the + * number of copied chartacters; the address of + * one character passed the last written non-NUL + * character. + */ +wchar_t* wcsstrncpy(wchar_t* restrict whither, const wchar_t* restrict whence, + const wchar_t* restrict str, size_t maxlen) +{ + const wchar_t* stop = wcsnstr(whence, str, maxlen); + size_t n = stop == NULL ? wcsnlen(whence, maxlen) : (size_t)(stop - whence); + wchar_t* r = stop == NULL ? NULL : (whither + n); + wmemcpy(whither, whence, n); + wmemset(whither, 0, maxlen - n); + return r; +} + |