1 files changed, 99 insertions, 0 deletions
diff --git a/wsrep-lib/include/wsrep/seqno.hpp b/wsrep-lib/include/wsrep/seqno.hpp
new file mode 100644
index 00000000..9d8cedbc
--- /dev/null
+++ b/wsrep-lib/include/wsrep/seqno.hpp
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2018 Codership Oy <info@codership.com>
+ *
+ * This file is part of wsrep-lib.
+ *
+ * Wsrep-lib is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Wsrep-lib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wsrep-lib.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef WSREP_SEQNO_HPP
+#define WSREP_SEQNO_HPP
+
+#include <iosfwd>
+
+namespace wsrep
+{
+    /** @class seqno
+     *
+     * Sequence number type.
+     */
+    class seqno
+    {
+    public:
+        typedef long long native_type;
+
+        seqno()
+            : seqno_(-1)
+        { }
+
+        explicit seqno(long long seqno)
+            : seqno_(seqno)
+        { }
+
+        long long get() const
+        {
+            return seqno_;
+        }
+
+        bool is_undefined() const
+        {
+            return (seqno_ == -1);
+        }
+
+        bool operator<(seqno other) const
+        {
+            return (seqno_ < other.seqno_);
+        }
+
+        bool operator>(seqno other) const
+        {
+            return (seqno_ > other.seqno_);
+        }
+
+        bool operator<=(seqno other) const
+        {
+            return !(seqno_ > other.seqno_);
+        }
+
+        bool operator>=(seqno other) const
+        {
+            return !(seqno_ < other.seqno_);
+        }
+
+        bool operator==(seqno other) const
+        {
+            return (seqno_ == other.seqno_);
+        }
+        bool operator!=(seqno other) const
+        {
+            return !(seqno_ == other.seqno_);
+        }
+        seqno operator+(seqno other) const
+        {
+            return (seqno(seqno_ + other.seqno_));
+        }
+        seqno operator+(long long other) const
+        {
+            return (*this + seqno(other));
+        }
+        static seqno undefined() { return seqno(-1); }
+
+    private:
+        native_type seqno_;
+    };
+
+    std::ostream& operator<<(std::ostream& os, wsrep::seqno seqno);
+}
+
+#endif // WSREP_SEQNO_HPP