return false instead of throwing on a url with nothing after the schema

libi2pd/HTTP.cpp

@@ -133,6 +133,7 @@ namespace http
 			}
 
 			/* hostname[:port][/path] */
+			if (pos_p >= url.length ()) return false; /* nothing left after schema or user part */
 			if (url.at(pos_p) == '[') // ipv6
 			{
 				auto pos_b = url.find(']', pos_p);

tests/test-http-url.cpp

@@ -125,6 +125,12 @@ int main() {
   assert(url->frag == "frag");
   delete url;
 
+  /* nothing after the schema or the user part: must not throw */
+  url = new URL;
+  assert(url->parse("http://") == false);
+  assert(url->parse("http://user@") == false);
+  delete url;
+
   return 0;
 }