Fix issue #13 (#15)

* `stream.IsNextSequence` or `stream.GoTo` froze when they meets end of the stream (#13)

stream.go

@@ -138,6 +138,20 @@ func (s *Stream) GoPrev() *Stream {
 // GoTo moves pointer of stream to specific token.
 // The search is done by token ID.
 func (s *Stream) GoTo(id int) *Stream {
+	if s.current == undefToken {
+		if s.prev != nil && id <= s.prev.id { // we at the end of the stream
+			s.GoPrev() // now current is available
+			for s.current != nil && id != s.current.id {
+				s.GoPrev()
+			}
+		} else if s.next != nil && id >= s.prev.id { // we at the beginning of the stream
+			s.GoNext() // now current is available
+			for s.current != nil && id != s.current.id {
+				s.GoNext()
+			}
+		}
+		return s
+	}
 	if id > s.current.id {
 		for s.current != nil && id != s.current.id {
 			s.GoNext()

stream_test.go

@@ -232,6 +232,17 @@ func TestInfStream(t *testing.T) {
 
 }
 
+func TestIssues13_SequenceLongerThenStream(t *testing.T) {
+	const TOK_CMD = 100
+	var parser = New()
+	parser.DefineTokens(TOK_CMD, []string{"CMD"})
+
+	stream := parser.ParseString("CMD CMD")
+
+	ok := stream.IsNextSequence(TOK_CMD, TOK_CMD, TOK_CMD, TOK_CMD)
+	require.False(t, ok)
+}
+
 var pattern = []byte(`<item count=10 valid id="n9762"> Носки <![CDATA[ socks ]]></item>`)
 
 type dataGenerator struct {