// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
/*
 * This file is open source software, licensed to you under the terms
 * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership.  You may not use this file except in compliance with the License.
 *
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/*
 * Copyright (C) 2014 Cloudius Systems, Ltd.
 */

#ifndef CEPH_MSG_CHECKSUM_H_
#define CEPH_MSG_CHECKSUM_H_

#include <cstdint>
#include <cstddef>
#include <arpa/inet.h>

#include "Packet.h"

uint16_t ip_checksum(const void* data, size_t len);

struct checksummer {
  __int128 csum = 0;
  bool odd = false;
  void sum(const char* data, size_t len);
  void sum(const Packet& p);
  void sum(uint8_t data) {
    if (!odd) {
      csum += data << 8;
    } else {
      csum += data;
    }
    odd = !odd;
  }
  void sum(uint16_t data) {
    if (odd) {
      sum(uint8_t(data >> 8));
      sum(uint8_t(data));
    } else {
      csum += data;
    }
  }
  void sum(uint32_t data) {
    if (odd) {
      sum(uint16_t(data));
      sum(uint16_t(data >> 16));
    } else {
      csum += data;
    }
  }
  void sum_many() {}
  template <typename T0, typename... T>
  void sum_many(T0 data, T... rest) {
    sum(data);
    sum_many(rest...);
  }
  uint16_t get() const;
};

#endif /* CEPH_MSG_CHECKSUM_H_ */
