src/system/libroot/posix/string/strstr.c

   1 /*
   2  * Taken from Wikipedia, which declared it as "public domain".
   3  */
   4
   5 #include <sys/types.h>
   6 #include <string.h>
   7
   8
   9 char *
  10 strstr(const char *s1, const char *s2)
  11 {
  12     size_t s2len;
  13     /* Check for the null s2 case. */
  14     if (*s2 == '\0')
  15         return (char *) s1;
  16     s2len = strlen(s2);
  17     for (; (s1 = strchr(s1, *s2)) != NULL; s1++) {
  18         if (strncmp(s1, s2, s2len) == 0)
  19             return (char *)s1;
  20     }
  21     return NULL;
  22 }
  23