Adding nsync for NLSR
diff --git a/nsync/src/sync-seq-no.h b/nsync/src/sync-seq-no.h
new file mode 100644
index 0000000..bf21704
--- /dev/null
+++ b/nsync/src/sync-seq-no.h
@@ -0,0 +1,198 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ * Chaoyi Bian <bcy@pku.edu.cn>
+ * Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ * Yingdi Yu <yingdi@cs.ucla.edu>
+ */
+
+#ifndef SYNC_SEQ_NO_H
+#define SYNC_SEQ_NO_H
+
+#include <boost/cstdint.hpp>
+#include "sync-digest.h"
+
+namespace Sync {
+
+/**
+ * @ingroup sync
+ * @brief Sequence number abstraction
+ */
+class SeqNo
+{
+public:
+ /**
+ * @brief Default constructor. Creates an zero sequence number with zero session ID (basically is an invalid object)
+ */
+ SeqNo ()
+ : m_valid (false)
+ , m_session (0)
+ , m_seq (0)
+ {
+ }
+
+ /**
+ * @brief Copy constructor
+ * @param seq sequence number object to copy from
+ */
+ SeqNo (const SeqNo &seq)
+ {
+ *this = seq;
+ }
+
+ /**
+ * @brief Assignment operator
+ * @param seq sequence number object to copy from
+ */
+ SeqNo &
+ operator = (const SeqNo &seq)
+ {
+ m_valid = seq.m_valid;
+ m_session = seq.m_session;
+ m_seq = seq.m_seq;
+
+ return *this;
+ }
+
+ /**
+ * @brief Constructor with just sequence number. Session assumed to be zero
+ * @param seq Sequence number
+ */
+ SeqNo (uint64_t seq)
+ : m_valid (true)
+ , m_session (0)
+ , m_seq (seq)
+ { }
+
+ /**
+ * @brief Constructor with session and sequence id
+ * @param session Session ID
+ * @param seq Sequence number
+ */
+ SeqNo (uint64_t session, uint64_t seq)
+ : m_valid (true)
+ , m_session (session)
+ , m_seq (seq)
+ { }
+
+ /**
+ * @brief Get sequence number digest
+ *
+ * Digest will be calculated every time it is requested
+ */
+ DigestConstPtr
+ getDigest () const;
+
+ /**
+ * @brief Compare if one sequence number is lower
+ * @param seq Another sequence number to compare with
+ *
+ * tuple (session1, seq1) is less than (session2, seq2) in two cases:
+ * 1. session1 < session2
+ * 2. session1 == session2 and seq1 < seq2
+ */
+ bool
+ operator < (const SeqNo &seq) const
+ {
+ return m_session < seq.m_session || (m_session == seq.m_session && m_seq < seq.m_seq);
+ }
+
+ /**
+ * @brief Compare if two sequence numbers are equal
+ * @param seq Another sequence number to compare with
+ */
+ bool
+ operator == (const SeqNo &seq) const
+ {
+ return m_session == seq.m_session && m_seq == seq.m_seq;
+ }
+
+ bool
+ operator <= (const SeqNo &seq) const
+ {
+ return m_session == seq.m_session && m_seq <= seq.m_seq;
+ }
+
+ SeqNo &
+ operator ++ ()
+ {
+ if (m_valid) {
+ m_seq ++;
+ }
+ else {
+ m_valid = true;
+ }
+ return *this;
+ }
+
+ bool
+ isValid () const
+ {
+ return m_valid;
+ }
+
+ /**
+ * @brief Get session id
+ */
+ uint64_t getSession () const
+ { return m_session; }
+
+ /**
+ * @brief Get sequence number
+ */
+ uint64_t getSeq () const
+ { return m_seq; }
+
+ /**
+ * @brief Set sequence number
+ */
+ void
+ setSeq(uint64_t seq)
+ { m_seq = seq; }
+
+private:
+ bool m_valid;
+
+ /**
+ * @brief Session ID (e.g., after crash, application will choose new session ID.
+ *
+ * Note that session IDs for the same name should always increase. So, the good choice
+ * for the session ID is client's timestamp
+ */
+ uint64_t m_session;
+
+ /**
+ * @brief Sequence number
+ *
+ * Sequence number for a session always starts with 0 and goes to max value.
+ *
+ * For now, wrapping sequence number after max to zero is not supported
+ */
+ uint64_t m_seq;
+};
+
+inline std::ostream &
+operator << (std::ostream &os, const SeqNo &seqno)
+{
+ os << "<session>" << seqno.getSession () << "</session><seqno>" << seqno.getSeq () << "</seqno>";
+ return os;
+}
+
+} // Sync
+
+#endif // SYNC_SEQ_NO_H