diff options
Diffstat (limited to 'REORG.TODO/wcsmbs/wcsstr.c')
| -rw-r--r-- | REORG.TODO/wcsmbs/wcsstr.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/REORG.TODO/wcsmbs/wcsstr.c b/REORG.TODO/wcsmbs/wcsstr.c new file mode 100644 index 0000000000..0a9fc4cc67 --- /dev/null +++ b/REORG.TODO/wcsmbs/wcsstr.c @@ -0,0 +1,97 @@ +/* Copyright (C) 1995-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library 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 C Library 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 the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* + * The original strstr() file contains the following comment: + * + * My personal strstr() implementation that beats most other algorithms. + * Until someone tells me otherwise, I assume that this is the + * fastest implementation of strstr() in C. + * I deliberately chose not to comment it. You should have at least + * as much fun trying to understand it, as I had to write it :-). + * + * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */ + +#include <wchar.h> + +wchar_t * +wcsstr (const wchar_t *haystack, const wchar_t *needle) +{ + wchar_t b, c; + + if ((b = *needle) != L'\0') + { + haystack--; /* possible ANSI violation */ + do + if ((c = *++haystack) == L'\0') + goto ret0; + while (c != b); + + if (!(c = *++needle)) + goto foundneedle; + ++needle; + goto jin; + + for (;;) + { + wchar_t a; + const wchar_t *rhaystack, *rneedle; + + do + { + if (!(a = *++haystack)) + goto ret0; + if (a == b) + break; + if ((a = *++haystack) == L'\0') + goto ret0; +shloop: ; + } + while (a != b); + +jin: if (!(a = *++haystack)) + goto ret0; + + if (a != c) + goto shloop; + + if (*(rhaystack = haystack-- + 1) == (a = *(rneedle = needle))) + do + { + if (a == L'\0') + goto foundneedle; + if (*++rhaystack != (a = *++needle)) + break; + if (a == L'\0') + goto foundneedle; + } + while (*++rhaystack == (a = *++needle)); + + needle = rneedle; /* took the register-poor approach */ + + if (a == L'\0') + break; + } + } +foundneedle: + return (wchar_t*) haystack; +ret0: + return NULL; +} +/* This alias is for backward compatibility with drafts of the ISO C + standard. Unfortunately the Unix(TM) standard requires this name. */ +weak_alias (wcsstr, wcswcs) |