missing/strstr.c

   1 /* public domain rewrite of strstr(3) */
   2
   3 char *
   4 strstr(const char *haystack, const char *needle)
   5 {
   6     const char *hend;
   7     const char *a, *b;
   8
   9     if (*needle == 0) return (char *)haystack;
  10     hend = haystack + strlen(haystack) - strlen(needle) + 1;
  11     while (haystack < hend) {
  12         if (*haystack == *needle) {
  13             a = haystack;
  14             b = needle;
  15             for (;;) {
  16                 if (*b == 0) return (char *)haystack;
  17                 if (*a++ != *b++) {
  18                     break;
  19                 }
  20             }
  21         }
  22         haystack++;
  23     }
  24     return 0;
  25 }