diff options
Diffstat (limited to 'lib/wcsstr-impl.h')
-rw-r--r-- | lib/wcsstr-impl.h | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/lib/wcsstr-impl.h b/lib/wcsstr-impl.h new file mode 100644 index 0000000000..f3fb3fb967 --- /dev/null +++ b/lib/wcsstr-impl.h @@ -0,0 +1,51 @@ +/* Locate a substring in a wide string. + Copyright (C) 1999, 2011 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 1999. + + 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/>. */ + +wchar_t * +wcsstr (const wchar_t *haystack, const wchar_t *needle) +{ + wchar_t n = needle[0]; + + /* Is needle empty? */ + if (n == (wchar_t)'\0') + return (wchar_t *) haystack; + + /* Is needle nearly empty? */ + if (needle[1] == (wchar_t)'\0') + return wcschr (haystack, n); + + /* Search for needle's first character. */ + for (; *haystack != (wchar_t)'\0'; haystack++) + { + if (*haystack == n) + { + /* Compare with needle's remaining characters. */ + const wchar_t *hptr = haystack + 1; + const wchar_t *nptr = needle + 1; + for (;;) + { + if (*hptr != *nptr) + break; + hptr++; nptr++; + if (*nptr == (wchar_t)'\0') + return (wchar_t *) haystack; + } + } + } + + return NULL; +} |