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+// Copyright (c) 2014-2016, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
+
+#pragma once
+#include <map>
+#include <vector>
+#include "cryptonote_basic_impl.h"
+#include "misc_log_ex.h"
+#include "storages/portable_storage_template_helper.h" // epee json include
+
+#define ADD_CHECKPOINT(h, hash)  CHECK_AND_ASSERT(add_checkpoint(h,  hash), false);
+#define JSON_HASH_FILE_NAME "checkpoints.json"
+
+
+namespace cryptonote
+{
+  /**
+   * @brief A container for blockchain checkpoints
+   *
+   * A checkpoint is a pre-defined hash for the block at a given height.
+   * Some of these are compiled-in, while others can be loaded at runtime
+   * either from a json file or via DNS from a checkpoint-hosting server.
+   */
+  class checkpoints
+  {
+  public:
+
+    /**
+     * @brief default constructor
+     */
+    checkpoints();
+
+    /**
+     * @brief adds a checkpoint to the container
+     *
+     * @param height the height of the block the checkpoint is for
+     * @param hash_str the hash of the block, as a string
+     *
+     * @return false if parsing the hash fails, or if the height is a duplicate
+     *         AND the existing checkpoint hash does not match the new one,
+     *         otherwise returns true
+     */
+    bool add_checkpoint(uint64_t height, const std::string& hash_str);
+
+    /**
+     * @brief checks if there is a checkpoint in the future
+     *
+     * This function checks if the height passed is lower than the highest
+     * checkpoint.
+     *
+     * @param height the height to check against
+     *
+     * @return false if no checkpoints, otherwise returns whether or not
+     *         the height passed is lower than the highest checkpoint.
+     */
+    bool is_in_checkpoint_zone(uint64_t height) const;
+
+    /**
+     * @brief checks if the given height and hash agree with the checkpoints
+     *
+     * This function checks if the given height and hash exist in the
+     * checkpoints container.  If so, it returns whether or not the passed
+     * parameters match the stored values.
+     *
+     * @param height the height to be checked
+     * @param h the hash to be checked
+     * @param is_a_checkpoint return-by-reference if there is a checkpoint at the given height
+     *
+     * @return true if there is no checkpoint at the given height,
+     *         true if the passed parameters match the stored checkpoint,
+     *         false otherwise
+     */
+    bool check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const;
+
+    /**
+     * @overload
+     */
+    bool check_block(uint64_t height, const crypto::hash& h) const;
+
+    /**
+     * @brief checks if alternate chain blocks should be kept for a given height
+     *
+     * this basically says if the blockchain is smaller than the first
+     * checkpoint then alternate blocks are allowed.  Alternatively, if the
+     * last checkpoint *before* the end of the current chain is also before
+     * the block to be added, then this is fine.
+     *
+     * @param blockchain_height the current blockchain height
+     * @param block_height the height of the block to be added as alternate
+     *
+     * @return true if alternate blocks are allowed given the parameters,
+     *         otherwise false
+     */
+    bool is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const;
+
+    /**
+     * @brief gets the highest checkpoint height
+     *
+     * @return the height of the highest checkpoint
+     */
+    uint64_t get_max_height() const;
+
+    /**
+     * @brief gets the checkpoints container
+     *
+     * @return a const reference to the checkpoints container
+     */
+    const std::map<uint64_t, crypto::hash>& get_points() const;
+
+    /**
+     * @brief checks if our checkpoints container conflicts with another
+     *
+     * A conflict refers to a case where both checkpoint sets have a checkpoint
+     * for a specific height but their hashes for that height do not match.
+     *
+     * @param other the other checkpoints instance to check against
+     *
+     * @return false if any conflict is found, otherwise true
+     */
+    bool check_for_conflicts(const checkpoints& other) const;
+
+    /**
+     * @brief loads the default main chain checkpoints
+     *
+     * @return true unless adding a checkpoint fails
+     */
+    bool init_default_checkpoints();
+
+    /**
+     * @brief load new checkpoints
+     *
+     * Loads new checkpoints from the specified json file, as well as
+     * (optionally) from DNS.
+     *
+     * @param json_hashfile_fullpath path to the json checkpoints file
+     * @param testnet whether to load testnet checkpoints or mainnet
+     * @param dns whether or not to load DNS checkpoints
+     *
+     * @return true if loading successful and no conflicts
+     */
+    bool load_new_checkpoints(const std::string json_hashfile_fullpath, bool testnet=false, bool dns=true);
+
+    /**
+     * @brief load new checkpoints from json
+     *
+     * @param json_hashfile_fullpath path to the json checkpoints file
+     *
+     * @return true if loading successful and no conflicts
+     */
+    bool load_checkpoints_from_json(const std::string json_hashfile_fullpath);
+
+    /**
+     * @brief load new checkpoints from DNS
+     *
+     * @param testnet whether to load testnet checkpoints or mainnet
+     *
+     * @return true if loading successful and no conflicts
+     */
+    bool load_checkpoints_from_dns(bool testnet = false);
+
+  private:
+
+
+    /**
+     * @brief struct for loading a checkpoint from json
+     */
+  struct t_hashline
+  {
+    uint64_t height; //!< the height of the checkpoint
+    std::string hash; //!< the hash for the checkpoint
+        BEGIN_KV_SERIALIZE_MAP()
+          KV_SERIALIZE(height)
+          KV_SERIALIZE(hash)
+        END_KV_SERIALIZE_MAP()
+  };
+
+  /**
+   * @brief struct for loading many checkpoints from json
+   */
+  struct t_hash_json {
+    std::vector<t_hashline> hashlines; //!< the checkpoint lines from the file
+        BEGIN_KV_SERIALIZE_MAP()
+          KV_SERIALIZE(hashlines)
+        END_KV_SERIALIZE_MAP()
+  };
+
+    std::map<uint64_t, crypto::hash> m_points; //!< the checkpoints container
+
+  };
+}