1 /* Copyright (C) 1995-2015 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
19 * The original strstr() file contains the following comment:
21 * My personal strstr() implementation that beats most other algorithms.
22 * Until someone tells me otherwise, I assume that this is the
23 * fastest implementation of strstr() in C.
24 * I deliberately chose not to comment it. You should have at least
25 * as much fun trying to understand it, as I had to write it :-).
27 * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */
32 wcsstr (haystack, needle)
33 const wchar_t *haystack;
34 const wchar_t *needle;
38 if ((b = *needle) != L'\0')
40 haystack--; /* possible ANSI violation */
42 if ((c = *++haystack) == L'\0')
54 const wchar_t *rhaystack, *rneedle;
58 if (!(a = *++haystack))
62 if ((a = *++haystack) == L'\0')
68 jin: if (!(a = *++haystack))
74 if (*(rhaystack = haystack-- + 1) == (a = *(rneedle = needle)))
79 if (*++rhaystack != (a = *++needle))
84 while (*++rhaystack == (a = *++needle));
86 needle = rneedle; /* took the register-poor approach */
93 return (wchar_t*) haystack;
97 /* This alias is for backward compatibility with drafts of the ISO C
98 standard. Unfortunately the Unix(TM) standard requires this name. */
99 weak_alias (wcsstr, wcswcs)