digest-tree.hpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
#ifndef NDN_DIGEST_TREE_HPP
#define NDN_DIGEST_TREE_HPP

#include <ndn-cpp/common.hpp>
#include <string>

namespace ndn {

class DigestTree {
public:
  DigestTree()
  : root_("00")
  {}

  class Node {
  public:
    Node(const std::string& dataPrefix, int sessionNo, int sequenceNo)
    : dataPrefix_(dataPrefix),
      sessionNo_(sessionNo),
      sequenceNo_(sequenceNo)
    {
      recomputeDigest();
    }

    const std::string&
    getDataPrefix() const { return dataPrefix_; }

    int
    getSessionNo() const { return sessionNo_; }

    int
    getSequenceNo() const { return sequenceNo_; }

    const std::string&
    getDigest() const { return digest_; }

    void
    setSequenceNo(int sequenceNo)
    {
      sequenceNo_ = sequenceNo;
      recomputeDigest();
    }

    class Compare {
    public:
      bool
      operator()
        (const ptr_lib::shared_ptr<const Node>& node1,
         const ptr_lib::shared_ptr<const Node>& node2) const
      {
        int nameComparison = node1->dataPrefix_.compare(node2->dataPrefix_);
        if (nameComparison != 0)
          return nameComparison < 0;

        return node1->sessionNo_ < node2->sessionNo_;
      }
    };

  private:
    void
    recomputeDigest();

    static void
    int32ToLittleEndian(uint32_t value, uint8_t* result);

    std::string dataPrefix_;
    int sessionNo_;
    int sequenceNo_;
    std::string digest_;
  };

  bool
  update(const std::string& dataPrefix, int sessionNo, int sequenceNo);

  int
  find(const std::string& dataPrefix, int sessionNo) const;

  size_t
  size() const { return digestNode_.size(); }

  const DigestTree::Node&
  get(size_t i) const { return *digestNode_[i]; }

  const std::string&
  getRoot() const { return root_; }

private:
  void
  recomputeRoot();

  std::vector<ptr_lib::shared_ptr<DigestTree::Node> > digestNode_;
  std::string root_;
  Node::Compare nodeCompare_;
};

}

#endif