+/* Returns the offset in HAYSTACK of the first instance of NEEDLE,
+ or SIZE_MAX if NEEDLE does not occur in HAYSTACK. */
+size_t
+ss_find_substring (struct substring haystack, struct substring needle)
+{
+ const char *p = memmem (haystack.string, haystack.length,
+ needle.string, needle.length);
+ return p != NULL ? p - haystack.string : SIZE_MAX;
+}
+