libc/string/strstr.c

   1 /*
   2  * Copyright (C) 2002     Manuel Novoa III
   3  * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
   4  *
   5  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
   6  */
   7
   8 #include "_string.h"
   9
  10 #ifdef WANT_WIDE
  11 # define Wstrstr wcsstr
  12 #else
  13 # define Wstrstr strstr
  14 #endif
  15
  16 /* NOTE: This is the simple-minded O(len(s1) * len(s2)) worst-case approach. */
  17
  18 Wchar *Wstrstr(const Wchar *s1, const Wchar *s2)
  19 {
  20         register const Wchar *s = s1;
  21         register const Wchar *p = s2;
  22
  23         do {
  24                 if (!*p) {
  25                         return (Wchar *) s1;;
  26                 }
  27                 if (*p == *s) {
  28                         ++p;
  29                         ++s;
  30                 } else {
  31                         p = s2;
  32                         if (!*s) {
  33                                 return NULL;
  34                         }
  35                         s = ++s1;
  36                 }
  37         } while (1);
  38 }
  39 #ifndef WANT_WIDE
  40 libc_hidden_def(strstr)
  41 #elif defined __UCLIBC_SUSV3_LEGACY__
  42 strong_alias(wcsstr,wcswcs)
  43 #endif