diff --git a/reader.go b/reader.go
index 280c4ff..cdc6764 100644
--- a/reader.go
+++ b/reader.go
@@ -33,10 +33,9 @@ func NewReader(src io.Reader) *Reader {
 func (r *Reader) Reset(src io.Reader) error {
 	decoderStateInit(r)
 	r.src = src
-	if r.buf != nil {
-		return nil
+	if r.buf == nil {
+		r.buf = make([]byte, readBufSize)
 	}
-	r.buf = make([]byte, readBufSize)
 	return nil
 }