text: /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
  /*
   * Copyright (c) 2013-2018 Regents of the University of California.
   *
   * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
   *
   * ndn-cxx library is free software: you can redistribute it and/or modify it under the
   * terms of the GNU Lesser General Public License as published by the Free Software
   * Foundation, either version 3 of the License, or (at your option) any later version.
   *
   * ndn-cxx library 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 Lesser General Public License for more details.
   *
   * You should have received copies of the GNU General Public License and GNU Lesser
   * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
   * <http://www.gnu.org/licenses/>.
   *
   * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
   */
  
  #ifndef NDN_CXX_SECURITY_TRANSFORM_DIGEST_FILTER_HPP
  #define NDN_CXX_SECURITY_TRANSFORM_DIGEST_FILTER_HPP
  
  #include "transform-base.hpp"
  #include "../security-common.hpp"
  
  namespace ndn {
  namespace security {
  namespace transform {
  
  /**
   * @brief The module to calculate digest.
   */
  class DigestFilter : public Transform
  {
  public:
    /**
     * @brief Create a digest module with algorithm @p algo
     */
    explicit
    DigestFilter(DigestAlgorithm algo);
  
    ~DigestFilter();
  
  private:
    /**
     * @brief Append data @p buf into digest calculation
     *
     * @return The number of bytes that have been accepted
     */
    size_t
    convert(const uint8_t* buf, size_t size) final;
  
    /**
     * @brief Finalize digest calculation and write the digest into next module.
     */
    void
    finalize() final;
  
  private:
    class Impl;
    const unique_ptr<Impl> m_impl;
  };
  
  unique_ptr<Transform>
  digestFilter(DigestAlgorithm algo);
  
  } // namespace transform
  } // namespace security
  } // namespace ndn
  
  #endif // NDN_CXX_SECURITY_TRANSFORM_DIGEST_FILTER_HPP
  