text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2015 The Bitcoin Core developers
  // Copyright (c) 2017-2018 The NavCoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "main.h"
  
  #include "addrman.h"
  #include "arith_uint256.h"
  #include "base58.h"
  #include "blockencodings.h"
  #include "chainparams.h"
  #include "checkpoints.h"
  #include "checkqueue.h"
  #include "consensus/consensus.h"
  #include "consensus/merkle.h"
  #include "consensus/validation.h"
  #include "core_io.h"
  #include "hash.h"
  #include "init.h"
  #include "merkleblock.h"
  #include "net.h"
  #include "policy/fees.h"
  #include "policy/policy.h"
  #include "pow.h"
  #include "primitives/block.h"
  #include "primitives/transaction.h"
  #include "random.h"
  #include "script/script.h"
  #include "script/sigcache.h"
  #include "script/standard.h"
  #include "tinyformat.h"
  #include "timedata.h"
  #include "txdb.h"
  #include "txmempool.h"
  #include "ui_interface.h"
  #include "undo.h"
  #include "util.h"
  #include "utilmoneystr.h"
  #include "utilstrencodings.h"
  #include "validationinterface.h"
  #include "versionbits.h"
  #include "wallet/wallet.h"
  
  #include <atomic>
  #include <sstream>
  
  #include <boost/algorithm/string/replace.hpp>
  #include <boost/algorithm/string/join.hpp>
  #include <boost/filesystem.hpp>
  #include <boost/filesystem/fstream.hpp>
  #include <boost/math/distributions/poisson.hpp>
  #include <boost/thread.hpp>
  
  using namespace std;
  
  #if defined(NDEBUG)
  # error "Navcoin cannot be compiled without assertions."
  #endif
  
  /**
   * Global state
   */
  
  CCriticalSection cs_main;
  
  BlockMap mapBlockIndex;
  CChain chainActive;
  CBlockIndex *pindexBestHeader = NULL;
  int64_t nTimeBestReceived = 0;
  CWaitableCriticalSection csBestBlock;
  CConditionVariable cvBlockChange;
  int nScriptCheckThreads = 0;
  bool fImporting = false;
  bool fReindex = false;
  bool fTxIndex = false;
  bool fAddressIndex = false;
  bool fTimestampIndex = false;
  bool fSpentIndex = false;
  bool fHavePruned = false;
  bool fPruneMode = false;
  bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
  bool fRequireStandard = true;
  bool fCheckBlockIndex = false;
  bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
  size_t nCoinCacheUsage = 5000 * 300;
  uint64_t nPruneTarget = 0;
  int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;
  bool fEnableReplacement = DEFAULT_ENABLE_REPLACEMENT;
  
  
  CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
  CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
  
  uint256 hashBestChain = uint256();
  CBlockIndex* pindexBest = NULL;
  
  set<pair<COutPoint, unsigned int> > setStakeSeen;
  
  CTxMemPool mempool(::minRelayTxFee);
  FeeFilterRounder filterRounder(::minRelayTxFee);
  
  struct IteratorComparator
  {
      template<typename I>
      bool operator()(const I& a, const I& b)
      {
          return &(*a) < &(*b);
      }
  };
  
  struct COrphanTx {
      CTransaction tx;
      NodeId fromPeer;
      int64_t nTimeExpire;
  };
  map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(cs_main);
  map<COutPoint, set<map<uint256, COrphanTx>::iterator, IteratorComparator>> mapOrphanTransactionsByPrev GUARDED_BY(cs_main);
  void EraseOrphansFor(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
  
  /**
   * Returns true if there are nRequired or more blocks of minVersion or above
   * in the last Consensus::Params::nMajorityWindow blocks, starting at pstart and going backwards.
   */
  static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned nRequired, const Consensus::Params& consensusParams);
  static void CheckBlockIndex(const Consensus::Params& consensusParams);
  
  /* Proof of Stake constants */
  
  extern std::set<std::pair<COutPoint, unsigned int> > setStakeSeen;
  
  arith_uint256 bnProofOfStakeLimit(~arith_uint256() >> 20);
  arith_uint256 bnProofOfStakeLimitV2(~arith_uint256() >> 20);
  
  /** Constant stuff for coinbase transactions we create: */
  CScript COINBASE_FLAGS;
  
  const string strMessageMagic = "Navcoin Signed Message:\n";
  
  
  enum FlushStateMode {
      FLUSH_STATE_NONE,
      FLUSH_STATE_IF_NEEDED,
      FLUSH_STATE_PERIODIC,
      FLUSH_STATE_ALWAYS
  };
  
  // Internal stuff
  namespace {
  
      struct CBlockIndexWorkComparator
      {
          bool operator()(CBlockIndex *pa, CBlockIndex *pb) const {
              // First sort by most total work, ...
              if (pa->nChainWork > pb->nChainWork) return false;
              if (pa->nChainWork < pb->nChainWork) return true;
  
              // ... then by earliest time received, ...
              if (pa->nSequenceId < pb->nSequenceId) return false;
              if (pa->nSequenceId > pb->nSequenceId) return true;
  
              // Use pointer address as tie breaker (should only happen with blocks
              // loaded from disk, as those all have id 0).
              if (pa < pb) return false;
              if (pa > pb) return true;
  
              // Identical blocks.
              return false;
          }
      };
  
      CBlockIndex *pindexBestInvalid;
  
      /**
       * The set of all CBlockIndex entries with BLOCK_VALID_TRANSACTIONS (for itself and all ancestors) and
       * as good as our current tip or better. Entries may be failed, though, and pruning nodes may be
       * missing the data for the block.
       */
      set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;
      /** Number of nodes with fSyncStarted. */
      int nSyncStarted = 0;
      /** All pairs A->B, where A (or one of its ancestors) misses transactions, but B has transactions.
       * Pruned nodes may have entries where B is missing data.
       */
      multimap<CBlockIndex*, CBlockIndex*> mapBlocksUnlinked;
  
      CCriticalSection cs_LastBlockFile;
      std::vector<CBlockFileInfo> vinfoBlockFile;
      int nLastBlockFile = 0;
      /** Global flag to indicate we should check to see if there are
       *  block/undo files that should be deleted.  Set on startup
       *  or if we allocate more file space when we're in prune mode
       */
      bool fCheckForPruning = false;
  
      /**
       * Every received block is assigned a unique and increasing identifier, so we
       * know which one to give priority in case of a fork.
       */
      CCriticalSection cs_nBlockSequenceId;
      /** Blocks loaded from disk are assigned id 0, so start the counter at 1. */
      uint32_t nBlockSequenceId = 1;
  
      /**
       * Sources of received blocks, saved to be able to send them reject
       * messages or ban them when processing happens afterwards. Protected by
       * cs_main.
       */
      map<uint256, NodeId> mapBlockSource;
  
      /**
       * Filter for transactions that were recently rejected by
       * AcceptToMemoryPool. These are not rerequested until the chain tip
       * changes, at which point the entire filter is reset. Protected by
       * cs_main.
       *
       * Without this filter we'd be re-requesting txs from each of our peers,
       * increasing bandwidth consumption considerably. For instance, with 100
       * peers, half of which relay a tx we don't accept, that might be a 50x
       * bandwidth increase. A flooding attacker attempting to roll-over the
       * filter using minimum-sized, 60byte, transactions might manage to send
       * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a
       * two minute window to send invs to us.
       *
       * Decreasing the false positive rate is fairly cheap, so we pick one in a
       * million to make it highly unlikely for users to have issues with this
       * filter.
       *
       * Memory used: 1.3 MB
       */
      boost::scoped_ptr<CRollingBloomFilter> recentRejects;
      uint256 hashRecentRejectsChainTip;
  
      /** Blocks that are in flight, and that are in the queue to be downloaded. Protected by cs_main. */
      struct QueuedBlock {
          uint256 hash;
          CBlockIndex* pindex;                                     //!< Optional.
          bool fValidatedHeaders;                                  //!< Whether this block has validated headers at the time of request.
          std::unique_ptr<PartiallyDownloadedBlock> partialBlock;  //!< Optional, used for CMPCTBLOCK downloads
      };
      map<uint256, pair<NodeId, list<QueuedBlock>::iterator> > mapBlocksInFlight;
  
      /** Stack of nodes which we have set to announce using compact blocks */
      list<NodeId> lNodesAnnouncingHeaderAndIDs;
  
      /** Number of preferable block download peers. */
      int nPreferredDownload = 0;
  
      /** Dirty block index entries. */
      set<CBlockIndex*> setDirtyBlockIndex;
  
      /** Dirty block file entries. */
      set<int> setDirtyFileInfo;
  
      /** Number of peers from which we're downloading blocks. */
      int nPeersWithValidatedDownloads = 0;
  
      /** Relay map, protected by cs_main. */
      typedef std::map<uint256, std::shared_ptr<const CTransaction>> MapRelay;
      MapRelay mapRelay;
      /** Expiration-time ordered list of (expire time, relay map entry) pairs, protected by cs_main). */
      std::deque<std::pair<int64_t, MapRelay::iterator>> vRelayExpiration;
  } // anon namespace
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // Registration of network node signals.
  //
  
  namespace {
  
  struct CBlockReject {
      unsigned char chRejectCode;
      string strRejectReason;
      uint256 hashBlock;
  };
  
  class CNodeHeaders
  {
  public:
      CNodeHeaders():
          maxSize(0),
          maxAvg(0)
      {
          maxSize = GetArg("-headerspamfiltermaxsize", DEFAULT_HEADER_SPAM_FILTER_MAX_SIZE);
          maxAvg = GetArg("-headerspamfiltermaxavg", DEFAULT_HEADER_SPAM_FILTER_MAX_AVG);
      }
  
      bool addHeaders(int nBegin, int nEnd)
      {
  
          if(nBegin > 0 && nEnd > 0 && maxSize && maxAvg)
          {
  
              for(int point = nBegin; point<= nEnd; point++)
              {
                  addPoint(point);
              }
  
              return true;
          }
  
          return false;
      }
  
      bool updateState(CValidationState& state, bool ret)
      {
          // No headers
          size_t size = points.size();
          if(size == 0)
              return ret;
  
          // Compute the number of the received headers
          size_t nHeaders = 0;
          for(auto point : points)
          {
              nHeaders += point.second;
          }
  
          // Compute the average value per height
          double nAvgValue = (double)nHeaders / size;
  
          // Ban the node if try to spam
          bool banNode = (nAvgValue >= 1.5 * maxAvg && size >= maxAvg) ||
                  (nAvgValue >= maxAvg && nHeaders >= maxSize) ||
                  (nHeaders >= maxSize * 3);
          if(banNode)
          {
              // Clear the points and ban the node
              points.clear();
              return state.DoS(100, false, REJECT_INVALID, "header-spam", false, "ban node for sending spam");
          }
  
          return ret;
      }
  
  private:
      void addPoint(int height)
      {
          // Erace the last element in the list
          if(points.size() == maxSize)
          {
              points.erase(points.begin());
          }
  
          // Add the point to the list
          int occurrence = 0;
          auto mi = points.find(height);
           if (mi != points.end())
               occurrence = (*mi).second;
           occurrence++;
           points[height] = occurrence;
       }
  
   private:
       std::map<int,int> points;
       size_t maxSize;
       size_t maxAvg;
   };
  
  /**
   * Maintain validation-specific state about nodes, protected by cs_main, instead
   * by CNode's own locks. This simplifies asynchronous operation, where
   * processing of incoming data is done after the ProcessMessage call returns,
   * and we're no longer holding the node's locks.
   */
  struct CNodeState {
      //! The peer's address
      CService address;
      //! Whether we have a fully established connection.
      bool fCurrentlyConnected;
      //! Accumulated misbehaviour score for this peer.
      int nMisbehavior;
      //! Whether this peer should be disconnected and banned (unless whitelisted).
      bool fShouldBan;
      //! String name of this peer (debugging/logging purposes).
      std::string name;
      //! List of asynchronously-determined block rejections to notify this peer about.
      std::vector<CBlockReject> rejects;
      //! The best known block we know this peer has announced.
      CBlockIndex *pindexBestKnownBlock;
      //! The hash of the last unknown block this peer has announced.
      uint256 hashLastUnknownBlock;
      //! The last full block we both have.
      CBlockIndex *pindexLastCommonBlock;
      //! The best header we have sent our peer.
      CBlockIndex *pindexBestHeaderSent;
      //! Length of current-streak of unconnecting headers announcements
      int nUnconnectingHeaders;
      //! Whether we've started headers synchronization with this peer.
      bool fSyncStarted;
      //! Since when we're stalling block download progress (in microseconds), or 0.
      int64_t nStallingSince;
      list<QueuedBlock> vBlocksInFlight;
      //! When the first entry in vBlocksInFlight started downloading. Don't care when vBlocksInFlight is empty.
      int64_t nDownloadingSince;
      int nBlocksInFlight;
      int nBlocksInFlightValidHeaders;
      //! Whether we consider this a preferred download peer.
      bool fPreferredDownload;
      //! Whether this peer wants invs or headers (when possible) for block announcements.
      bool fPreferHeaders;
      //! Whether this peer wants invs or cmpctblocks (when possible) for block announcements.
      bool fPreferHeaderAndIDs;
      //! Whether this peer will send us cmpctblocks if we request them
      bool fProvidesHeaderAndIDs;
      //! Whether this peer can give us witnesses
      bool fHaveWitness;
  
      CNodeState() {
          fCurrentlyConnected = false;
          nMisbehavior = 0;
          fShouldBan = false;
          pindexBestKnownBlock = NULL;
          hashLastUnknownBlock.SetNull();
          pindexLastCommonBlock = NULL;
          pindexBestHeaderSent = NULL;
          nUnconnectingHeaders = 0;
          fSyncStarted = false;
          nStallingSince = 0;
          nDownloadingSince = 0;
          nBlocksInFlight = 0;
          nBlocksInFlightValidHeaders = 0;
          fPreferredDownload = false;
          fPreferHeaders = false;
          fPreferHeaderAndIDs = false;
          fProvidesHeaderAndIDs = false;
          fHaveWitness = false;
      }
  };
  
  /** Map maintaining per-node state. Requires cs_main. */
  map<NodeId, CNodeState> mapNodeState;
  map<CService, CNodeHeaders> mapServiceHeaders;
  
  // Requires cs_main.
  CNodeState *State(NodeId pnode) {
      map<NodeId, CNodeState>::iterator it = mapNodeState.find(pnode);
      if (it == mapNodeState.end())
          return NULL;
      return &it->second;
  }
  
  static CNodeHeaders &ServiceHeaders(const CService& address) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
      unsigned short port =
              GetBoolArg("-headerspamfilterignoreport", DEFAULT_HEADER_SPAM_FILTER_IGNORE_PORT) ? 0 : address.GetPort();
      CService addr(address, port);
      return mapServiceHeaders[addr];
  }
  
  static void CleanAddressHeaders(const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
      CSubNet subNet(addr);
      for (std::map<CService, CNodeHeaders>::iterator it=mapServiceHeaders.begin(); it!=mapServiceHeaders.end();){
          if(subNet.Match(it->first))
          {
              it = mapServiceHeaders.erase(it);
          }
          else{
              it++;
          }
      }
  }
  
  int GetHeight()
  {
      LOCK(cs_main);
      return chainActive.Height();
  }
  
  void UpdatePreferredDownload(CNode* node, CNodeState* state)
  {
      nPreferredDownload -= state->fPreferredDownload;
  
      // Whether this node should be marked as a preferred download node.
      state->fPreferredDownload = (!node->fInbound || node->fWhitelisted) && !node->fOneShot && !node->fClient;
  
      nPreferredDownload += state->fPreferredDownload;
  }
  
  void InitializeNode(NodeId nodeid, const CNode *pnode) {
      LOCK(cs_main);
      CNodeState &state = mapNodeState.insert(std::make_pair(nodeid, CNodeState())).first->second;
      state.name = pnode->addrName;
      state.address = pnode->addr;
  }
  
  void FinalizeNode(NodeId nodeid) {
      LOCK(cs_main);
      CNodeState *state = State(nodeid);
  
      if (state->fSyncStarted)
          nSyncStarted--;
  
      if (state->nMisbehavior == 0 && state->fCurrentlyConnected) {
          AddressCurrentlyConnected(state->address);
      }
  
      BOOST_FOREACH(const QueuedBlock& entry, state->vBlocksInFlight) {
          mapBlocksInFlight.erase(entry.hash);
      }
      EraseOrphansFor(nodeid);
      nPreferredDownload -= state->fPreferredDownload;
      nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0);
      assert(nPeersWithValidatedDownloads >= 0);
  
      mapNodeState.erase(nodeid);
  
      if (mapNodeState.empty()) {
          // Do a consistency check after the last peer is removed.
          assert(mapBlocksInFlight.empty());
          assert(nPreferredDownload == 0);
          assert(nPeersWithValidatedDownloads == 0);
      }
  }
  
  // Requires cs_main.
  // Returns a bool indicating whether we requested this block.
  // Also used if a block was /not/ received and timed out or started with another peer
  bool MarkBlockAsReceived(const uint256& hash) {
      map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
      if (itInFlight != mapBlocksInFlight.end()) {
          CNodeState *state = State(itInFlight->second.first);
          state->nBlocksInFlightValidHeaders -= itInFlight->second.second->fValidatedHeaders;
          if (state->nBlocksInFlightValidHeaders == 0 && itInFlight->second.second->fValidatedHeaders) {
              // Last validated block on the queue was received.
              nPeersWithValidatedDownloads--;
          }
          if (state->vBlocksInFlight.begin() == itInFlight->second.second) {
              // First block on the queue was received, update the start download time for the next one
              state->nDownloadingSince = std::max(state->nDownloadingSince, GetTimeMicros());
          }
          state->vBlocksInFlight.erase(itInFlight->second.second);
          state->nBlocksInFlight--;
          state->nStallingSince = 0;
          mapBlocksInFlight.erase(itInFlight);
          return true;
      }
      return false;
  }
  
  // Requires cs_main.
  // returns false, still setting pit, if the block was already in flight from the same peer
  // pit will only be valid as long as the same cs_main lock is being held
  bool MarkBlockAsInFlight(NodeId nodeid, const uint256& hash, const Consensus::Params& consensusParams, CBlockIndex *pindex = NULL, list<QueuedBlock>::iterator **pit = NULL) {
      CNodeState *state = State(nodeid);
      assert(state != NULL);
  
      // Short-circuit most stuff in case its from the same node
      map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
      if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) {
          *pit = &itInFlight->second.second;
          return false;
      }
  
      // Make sure it's not listed somewhere already.
      MarkBlockAsReceived(hash);
  
      list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(),
              {hash, pindex, pindex != NULL, std::unique_ptr<PartiallyDownloadedBlock>(pit ? new PartiallyDownloadedBlock(&mempool) : NULL)});
      state->nBlocksInFlight++;
      state->nBlocksInFlightValidHeaders += it->fValidatedHeaders;
      if (state->nBlocksInFlight == 1) {
          // We're starting a block download (batch) from this peer.
          state->nDownloadingSince = GetTimeMicros();
      }
      if (state->nBlocksInFlightValidHeaders == 1 && pindex != NULL) {
          nPeersWithValidatedDownloads++;
      }
      itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it))).first;
      if (pit)
          *pit = &itInFlight->second.second;
      return true;
  }
  
  /** Check whether the last unknown block a peer advertised is not yet known. */
  void ProcessBlockAvailability(NodeId nodeid) {
      CNodeState *state = State(nodeid);
      assert(state != NULL);
  
      if (!state->hashLastUnknownBlock.IsNull()) {
          BlockMap::iterator itOld = mapBlockIndex.find(state->hashLastUnknownBlock);
  
          if (itOld != mapBlockIndex.end()) {
              if (state->pindexBestKnownBlock == NULL || itOld->second->nChainWork >= state->pindexBestKnownBlock->nChainWork){
                  state->pindexBestKnownBlock = itOld->second;
              }
              state->hashLastUnknownBlock.SetNull();
          }
      }
  }
  
  /** Update tracking information about which blocks a peer is assumed to have. */
  void UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) {
      CNodeState *state = State(nodeid);
      assert(state != NULL);
  
      ProcessBlockAvailability(nodeid);
  
      BlockMap::iterator it = mapBlockIndex.find(hash);
      if (it != mapBlockIndex.end() && it->second->nChainWork > 0) {
          // An actually better block was announced.
          if (state->pindexBestKnownBlock == NULL || it->second->nChainWork >= state->pindexBestKnownBlock->nChainWork)
              state->pindexBestKnownBlock = it->second;
      } else {
          // An unknown block was announced; just assume that the latest one is the best one.
          state->hashLastUnknownBlock = hash;
      }
  }
  
  //void MaybeSetPeerAsAnnouncingHeaderAndIDs(const CNodeState* nodestate, CNode* pfrom) {
  //    if (nLocalServices & NODE_WITNESS) {
  //        // Don't ever request compact blocks when segwit is enabled.
  //        return;
  //    }
  //    if (nodestate->fProvidesHeaderAndIDs) {
  //        BOOST_FOREACH(const NodeId nodeid, lNodesAnnouncingHeaderAndIDs)
  //            if (nodeid == pfrom->GetId())
  //                return;
  //        bool fAnnounceUsingCMPCTBLOCK = false;
  //        uint64_t nCMPCTBLOCKVersion = 1;
  //        if (lNodesAnnouncingHeaderAndIDs.size() >= 3) {
  //            // As per BIP152, we only get 3 of our peers to announce
  //            // blocks using compact encodings.
  //            CNode* pnodeStop = FindNode(lNodesAnnouncingHeaderAndIDs.front());
  //            if (pnodeStop) {
  //                pnodeStop->PushMessage(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
  //                lNodesAnnouncingHeaderAndIDs.pop_front();
  //            }
  //        }
  //        fAnnounceUsingCMPCTBLOCK = true;
  //        pfrom->PushMessage(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
  //        lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
  //    }
  //}
  
  // Requires cs_main
  bool CanDirectFetch(const Consensus::Params &consensusParams)
  {
      return chainActive.Tip()->GetBlockTime() > GetAdjustedTime() - consensusParams.nPowTargetSpacing * 20;
  }
  
  // Requires cs_main
  bool PeerHasHeader(CNodeState *state, CBlockIndex *pindex)
  {
      if (state->pindexBestKnownBlock && pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight))
          return true;
      if (state->pindexBestHeaderSent && pindex == state->pindexBestHeaderSent->GetAncestor(pindex->nHeight))
          return true;
      return false;
  }
  
  /** Find the last common ancestor two blocks have.
   *  Both pa and pb must be non-NULL. */
  CBlockIndex* LastCommonAncestor(CBlockIndex* pa, CBlockIndex* pb) {
      if (pa->nHeight > pb->nHeight) {
          pa = pa->GetAncestor(pb->nHeight);
      } else if (pb->nHeight > pa->nHeight) {
          pb = pb->GetAncestor(pa->nHeight);
      }
  
      while (pa != pb && pa && pb) {
          pa = pa->pprev;
          pb = pb->pprev;
      }
  
      // Eventually all chain branches meet at the genesis block.
      assert(pa == pb);
      return pa;
  }
  
  /** Update pindexLastCommonBlock and add not-in-flight missing successors to vBlocks, until it has
   *  at most count entries. */
  void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vector<CBlockIndex*>& vBlocks, NodeId& nodeStaller) {
      if (count == 0)
          return;
  
      vBlocks.reserve(vBlocks.size() + count);
      CNodeState *state = State(nodeid);
      assert(state != NULL);
  
      // Make sure pindexBestKnownBlock is up to date, we'll need it.
      ProcessBlockAvailability(nodeid);
  
      if (state->pindexBestKnownBlock == NULL || state->pindexBestKnownBlock->nChainWork < chainActive.Tip()->nChainWork) {
          // This peer has nothing interesting.
          return;
      }
  
      if (state->pindexLastCommonBlock == NULL) {
          // Bootstrap quickly by guessing a parent of our best tip is the forking point.
          // Guessing wrong in either direction is not a problem.
          state->pindexLastCommonBlock = chainActive[std::min(state->pindexBestKnownBlock->nHeight, chainActive.Height())];
      }
  
      // If the peer reorganized, our previous pindexLastCommonBlock may not be an ancestor
      // of its current tip anymore. Go back enough to fix that.
      state->pindexLastCommonBlock = LastCommonAncestor(state->pindexLastCommonBlock, state->pindexBestKnownBlock);
      if (state->pindexLastCommonBlock == state->pindexBestKnownBlock)
          return;
  
      std::vector<CBlockIndex*> vToFetch;
      CBlockIndex *pindexWalk = state->pindexLastCommonBlock;
      // Never fetch further than the best block we know the peer has, or more than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last
      // linked block we have in common with this peer. The +1 is so we can detect stalling, namely if we would be able to
      // download that next block if the window were 1 larger.
      int nWindowEnd = state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW;
      int nMaxHeight = std::min<int>(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1);
      NodeId waitingfor = -1;
      while (pindexWalk->nHeight < nMaxHeight) {
          // Read up to 128 (or more, if more blocks than that are needed) successors of pindexWalk (towards
          // pindexBestKnownBlock) into vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as expensive
          // as iterating over ~100 CBlockIndex* entries anyway.
          int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight, std::max<int>(count - vBlocks.size(), 128));
          vToFetch.resize(nToFetch);
          pindexWalk = state->pindexBestKnownBlock->GetAncestor(pindexWalk->nHeight + nToFetch);
          vToFetch[nToFetch - 1] = pindexWalk;
          for (unsigned int i = nToFetch - 1; i > 0; i--) {
              vToFetch[i - 1] = vToFetch[i]->pprev;
          }
  
          // Iterate over those blocks in vToFetch (in forward direction), adding the ones that
          // are not yet downloaded and not in flight to vBlocks. In the mean time, update
          // pindexLastCommonBlock as long as all ancestors are already downloaded, or if it's
          // already part of our chain (and therefore don't need it even if pruned).
          BOOST_FOREACH(CBlockIndex* pindex, vToFetch) {
              if (!pindex->IsValid(BLOCK_VALID_TREE)) {
                  // We consider the chain that this peer is on invalid.
                  return;
              }
              if (pindex->nStatus & BLOCK_HAVE_DATA || chainActive.Contains(pindex)) {
                  if (pindex->nChainTx)
                      state->pindexLastCommonBlock = pindex;
              } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) {
                  // The block is not already downloaded, and not yet in flight.
                  if (pindex->nHeight > nWindowEnd) {
                      // We reached the end of the window.
                      if (vBlocks.size() == 0 && waitingfor != nodeid) {
                          // We aren't able to fetch anything, but we would be if the download window was one larger.
                          nodeStaller = waitingfor;
                      }
                      return;
                  }
                  vBlocks.push_back(pindex);
                  if (vBlocks.size() == count) {
                      return;
                  }
              } else if (waitingfor == -1) {
                  // This is the first already-in-flight block.
                  waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first;
              }
          }
      }
  }
  
  } // anon namespace
  
  bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) {
      LOCK(cs_main);
      CNodeState *state = State(nodeid);
      if (state == NULL)
          return false;
      stats.nMisbehavior = state->nMisbehavior;
      stats.nSyncHeight = state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1;
      stats.nCommonHeight = state->pindexLastCommonBlock ? state->pindexLastCommonBlock->nHeight : -1;
      BOOST_FOREACH(const QueuedBlock& queue, state->vBlocksInFlight) {
          if (queue.pindex)
              stats.vHeightInFlight.push_back(queue.pindex->nHeight);
      }
      return true;
  }
  
  void RegisterNodeSignals(CNodeSignals& nodeSignals)
  {
      nodeSignals.GetHeight.connect(&GetHeight);
      nodeSignals.ProcessMessages.connect(&ProcessMessages);
      nodeSignals.SendMessages.connect(&SendMessages);
      nodeSignals.InitializeNode.connect(&InitializeNode);
      nodeSignals.FinalizeNode.connect(&FinalizeNode);
  }
  
  void UnregisterNodeSignals(CNodeSignals& nodeSignals)
  {
      nodeSignals.GetHeight.disconnect(&GetHeight);
      nodeSignals.ProcessMessages.disconnect(&ProcessMessages);
      nodeSignals.SendMessages.disconnect(&SendMessages);
      nodeSignals.InitializeNode.disconnect(&InitializeNode);
      nodeSignals.FinalizeNode.disconnect(&FinalizeNode);
  }
  
  CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
  {
      // Find the first block the caller has in the main chain
      BOOST_FOREACH(const uint256& hash, locator.vHave) {
          BlockMap::iterator mi = mapBlockIndex.find(hash);
          if (mi != mapBlockIndex.end())
          {
              CBlockIndex* pindex = (*mi).second;
              if (chain.Contains(pindex))
                  return pindex;
              if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
                  return chain.Tip();
              }
          }
      }
      return chain.Genesis();
  }
  
  CCoinsViewCache *pcoinsTip = NULL;
  CBlockTreeDB *pblocktree = NULL;
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // mapOrphanTransactions
  //
  
  bool AddOrphanTx(const CTransaction& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
  {
      uint256 hash = tx.GetHash();
      if (mapOrphanTransactions.count(hash))
          return false;
  
      // Ignore big transactions, to avoid a
      // send-big-orphans memory exhaustion attack. If a peer has a legitimate
      // large transaction with a missing parent then we assume
      // it will rebroadcast it later, after the parent transaction(s)
      // have been mined or received.
      // 100 orphans, each of which is at most 99,999 bytes big is
      // at most 10 megabytes of orphans and somewhat more byprev index (in the worst case):
      unsigned int sz = GetTransactionWeight(tx);
      if (sz >= MAX_STANDARD_TX_WEIGHT)
      {
          LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
          return false;
      }
  
      auto ret = mapOrphanTransactions.emplace(hash, COrphanTx{tx, peer, GetTime() + ORPHAN_TX_EXPIRE_TIME});
      assert(ret.second);
      BOOST_FOREACH(const CTxIn& txin, tx.vin) {
          mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first);
      }
  
      LogPrint("mempool", "stored orphan tx %s (mapsz %u outsz %u)\n", hash.ToString(),
               mapOrphanTransactions.size(), mapOrphanTransactionsByPrev.size());
      return true;
  }
  
  int static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
  {
      map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.find(hash);
      if (it == mapOrphanTransactions.end())
          return 0;
      BOOST_FOREACH(const CTxIn& txin, it->second.tx.vin)
      {
          auto itPrev = mapOrphanTransactionsByPrev.find(txin.prevout);
          if (itPrev == mapOrphanTransactionsByPrev.end())
              continue;
          itPrev->second.erase(it);
          if (itPrev->second.empty())
              mapOrphanTransactionsByPrev.erase(itPrev);
      }
      mapOrphanTransactions.erase(it);
      return 1;
  }
  
  void EraseOrphansFor(NodeId peer)
  {
      int nErased = 0;
      map<uint256, COrphanTx>::iterator iter = mapOrphanTransactions.begin();
      while (iter != mapOrphanTransactions.end())
      {
          map<uint256, COrphanTx>::iterator maybeErase = iter++; // increment to avoid iterator becoming invalid
          if (maybeErase->second.fromPeer == peer)
          {
              nErased += EraseOrphanTx(maybeErase->second.tx.GetHash());
          }
      }
      if (nErased > 0) LogPrint("mempool", "Erased %d orphan tx from peer %d\n", nErased, peer);
  }
  
  
  unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
  {
      unsigned int nEvicted = 0;
      static int64_t nNextSweep;
      int64_t nNow = GetTime();
      if (nNextSweep <= nNow) {
          // Sweep out expired orphan pool entries:
          int nErased = 0;
          int64_t nMinExpTime = nNow + ORPHAN_TX_EXPIRE_TIME - ORPHAN_TX_EXPIRE_INTERVAL;
          map<uint256, COrphanTx>::iterator iter = mapOrphanTransactions.begin();
          while (iter != mapOrphanTransactions.end())
          {
              map<uint256, COrphanTx>::iterator maybeErase = iter++;
              if (maybeErase->second.nTimeExpire <= nNow) {
                  nErased += EraseOrphanTx(maybeErase->second.tx.GetHash());
              } else {
                  nMinExpTime = std::min(maybeErase->second.nTimeExpire, nMinExpTime);
              }
          }
          // Sweep again 5 minutes after the next entry that expires in order to batch the linear scan.
          nNextSweep = nMinExpTime + ORPHAN_TX_EXPIRE_INTERVAL;
          if (nErased > 0) LogPrint("mempool", "Erased %d orphan tx due to expiration\n", nErased);
      }
      while (mapOrphanTransactions.size() > nMaxOrphans)
      {
          // Evict a random orphan:
          uint256 randomhash = GetRandHash();
          map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
          if (it == mapOrphanTransactions.end())
              it = mapOrphanTransactions.begin();
          EraseOrphanTx(it->first);
          ++nEvicted;
      }
      return nEvicted;
  }
  
  bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
  {
      if (tx.nLockTime == 0)
          return true;
      if ((int64_t)tx.nLockTime < ((int64_t)tx.nLockTime < LOCKTIME_THRESHOLD ? (int64_t)nBlockHeight : nBlockTime))
          return true;
      BOOST_FOREACH(const CTxIn& txin, tx.vin) {
          if (!(txin.nSequence == CTxIn::SEQUENCE_FINAL))
              return false;
      }
      return true;
  }
  
  bool CheckFinalTx(const CTransaction &tx, int flags)
  {
      AssertLockHeld(cs_main);
  
      // By convention a negative value for flags indicates that the
      // current network-enforced consensus rules should be used. In
      // a future soft-fork scenario that would mean checking which
      // rules would be enforced for the next block and setting the
      // appropriate flags. At the present time no soft-forks are
      // scheduled, so no flags are set.
      flags = std::max(flags, 0);
  
      // CheckFinalTx() uses chainActive.Height()+1 to evaluate
      // nLockTime because when IsFinalTx() is called within
      // CBlock::AcceptBlock(), the height of the block *being*
      // evaluated is what is used. Thus if we want to know if a
      // transaction can be part of the *next* block, we need to call
      // IsFinalTx() with one more than chainActive.Height().
      const int nBlockHeight = chainActive.Height() + 1;
  
      // BIP113 will require that time-locked transactions have nLockTime set to
      // less than the median time of the previous block they're contained in.
      // When the next block is created its previous block will be the current
      // chain tip, so we use that to calculate the median time passed to
      // IsFinalTx() if LOCKTIME_MEDIAN_TIME_PAST is set.
      const int64_t nBlockTime = (flags & LOCKTIME_MEDIAN_TIME_PAST)
                               ? chainActive.Tip()->GetMedianTimePast()
                               : GetAdjustedTime();
  
      return IsFinalTx(tx, nBlockHeight, nBlockTime);
  }
  
  /**
   * Calculates the block height and previous block's median time past at
   * which the transaction will be considered final in the context of BIP 68.
   * Also removes from the vector of input heights any entries which did not
   * correspond to sequence locked inputs as they do not affect the calculation.
   */
  static std::pair<int, int64_t> CalculateSequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
  {
      assert(prevHeights->size() == tx.vin.size());
  
      // Will be set to the equivalent height- and time-based nLockTime
      // values that would be necessary to satisfy all relative lock-
      // time constraints given our view of block chain history.
      // The semantics of nLockTime are the last invalid height/time, so
      // use -1 to have the effect of any height or time being valid.
      int nMinHeight = -1;
      int64_t nMinTime = -1;
  
      // tx.nVersion is signed integer so requires cast to unsigned otherwise
      // we would be doing a signed comparison and half the range of nVersion
      // wouldn't support BIP 68.
      bool fEnforceBIP68 = static_cast<uint32_t>(tx.nVersion) >= 2
                        && flags & LOCKTIME_VERIFY_SEQUENCE;
  
      // Do not enforce sequence numbers as a relative lock time
      // unless we have been instructed to
      if (!fEnforceBIP68) {
          return std::make_pair(nMinHeight, nMinTime);
      }
  
      for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
          const CTxIn& txin = tx.vin[txinIndex];
  
          // Sequence numbers with the most significant bit set are not
          // treated as relative lock-times, nor are they given any
          // consensus-enforced meaning at this point.
          if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) {
              // The height of this input is not relevant for sequence locks
              (*prevHeights)[txinIndex] = 0;
              continue;
          }
  
          int nCoinHeight = (*prevHeights)[txinIndex];
  
          if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) {
              int64_t nCoinTime = block.GetAncestor(std::max(nCoinHeight-1, 0))->GetMedianTimePast();
              // NOTE: Subtract 1 to maintain nLockTime semantics
              // BIP 68 relative lock times have the semantics of calculating
              // the first block or time at which the transaction would be
              // valid. When calculating the effective block time or height
              // for the entire transaction, we switch to using the
              // semantics of nLockTime which is the last invalid block
              // time or height.  Thus we subtract 1 from the calculated
              // time or height.
  
              // Time-based relative lock-times are measured from the
              // smallest allowed timestamp of the block containing the
              // txout being spent, which is the median time past of the
              // block prior.
              nMinTime = std::max(nMinTime, nCoinTime + (int64_t)((txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) << CTxIn::SEQUENCE_LOCKTIME_GRANULARITY) - 1);
          } else {
              nMinHeight = std::max(nMinHeight, nCoinHeight + (int)(txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) - 1);
          }
      }
  
      return std::make_pair(nMinHeight, nMinTime);
  }
  
  static bool EvaluateSequenceLocks(const CBlockIndex& block, std::pair<int, int64_t> lockPair)
  {
      assert(block.pprev);
      int64_t nBlockTime = block.pprev->GetMedianTimePast();
      if (lockPair.first >= block.nHeight || lockPair.second >= nBlockTime)
          return false;
  
      return true;
  }
  
  bool SequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
  {
      return EvaluateSequenceLocks(block, CalculateSequenceLocks(tx, flags, prevHeights, block));
  }
  
  bool TestLockPointValidity(const LockPoints* lp)
  {
      AssertLockHeld(cs_main);
      assert(lp);
      // If there are relative lock times then the maxInputBlock will be set
      // If there are no relative lock times, the LockPoints don't depend on the chain
      if (lp->maxInputBlock) {
          // Check whether chainActive is an extension of the block at which the LockPoints
          // calculation was valid.  If not LockPoints are no longer valid
          if (!chainActive.Contains(lp->maxInputBlock)) {
              return false;
          }
      }
  
      // LockPoints still valid
      return true;
  }
  
  bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool useExistingLockPoints)
  {
      AssertLockHeld(cs_main);
      AssertLockHeld(mempool.cs);
  
      CBlockIndex* tip = chainActive.Tip();
      CBlockIndex index;
      index.pprev = tip;
      // CheckSequenceLocks() uses chainActive.Height()+1 to evaluate
      // height based locks because when SequenceLocks() is called within
      // ConnectBlock(), the height of the block *being*
      // evaluated is what is used.
      // Thus if we want to know if a transaction can be part of the
      // *next* block, we need to use one more than chainActive.Height()
      index.nHeight = tip->nHeight + 1;
  
      std::pair<int, int64_t> lockPair;
      if (useExistingLockPoints) {
          assert(lp);
          lockPair.first = lp->height;
          lockPair.second = lp->time;
      }
      else {
          // pcoinsTip contains the UTXO set for chainActive.Tip()
          CCoinsViewMemPool viewMemPool(pcoinsTip, mempool);
          std::vector<int> prevheights;
          prevheights.resize(tx.vin.size());
          for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
              const CTxIn& txin = tx.vin[txinIndex];
              CCoins coins;
              if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
                  return error("%s: Missing input", __func__);
              }
              if (coins.nHeight == MEMPOOL_HEIGHT) {
                  // Assume all mempool transaction confirm in the next block
                  prevheights[txinIndex] = tip->nHeight + 1;
              } else {
                  prevheights[txinIndex] = coins.nHeight;
              }
          }
          lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
          if (lp) {
              lp->height = lockPair.first;
              lp->time = lockPair.second;
              // Also store the hash of the block with the highest height of
              // all the blocks which have sequence locked prevouts.
              // This hash needs to still be on the chain
              // for these LockPoint calculations to be valid
              // Note: It is impossible to correctly calculate a maxInputBlock
              // if any of the sequence locked inputs depend on unconfirmed txs,
              // except in the special case where the relative lock time/height
              // is 0, which is equivalent to no sequence lock. Since we assume
              // input height of tip+1 for mempool txs and test the resulting
              // lockPair from CalculateSequenceLocks against tip+1.  We know
              // EvaluateSequenceLocks will fail if there was a non-zero sequence
              // lock on a mempool input, so we can use the return value of
              // CheckSequenceLocks to indicate the LockPoints validity
              int maxInputHeight = 0;
              BOOST_FOREACH(int height, prevheights) {
                  // Can ignore mempool inputs since we'll fail if they had non-zero locks
                  if (height != tip->nHeight+1) {
                      maxInputHeight = std::max(maxInputHeight, height);
                  }
              }
              lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
          }
      }
      return EvaluateSequenceLocks(index, lockPair);
  }
  
  
  unsigned int GetLegacySigOpCount(const CTransaction& tx)
  {
      unsigned int nSigOps = 0;
      BOOST_FOREACH(const CTxIn& txin, tx.vin)
      {
          nSigOps += txin.scriptSig.GetSigOpCount(false);
      }
      BOOST_FOREACH(const CTxOut& txout, tx.vout)
      {
          nSigOps += txout.scriptPubKey.GetSigOpCount(false);
      }
      return nSigOps;
  }
  
  unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& inputs)
  {
      if (tx.IsCoinBase())
          return 0;
  
      unsigned int nSigOps = 0;
      for (unsigned int i = 0; i < tx.vin.size(); i++)
      {
          const CTxOut &prevout = inputs.GetOutputFor(tx.vin[i]);
          if (prevout.scriptPubKey.IsPayToScriptHash())
              nSigOps += prevout.scriptPubKey.GetSigOpCount(tx.vin[i].scriptSig);
      }
      return nSigOps;
  }
  
  int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, int flags)
  {
      int64_t nSigOps = GetLegacySigOpCount(tx) * WITNESS_SCALE_FACTOR;
  
      if (tx.IsCoinBase())
          return nSigOps;
  
      if (flags & SCRIPT_VERIFY_P2SH) {
          nSigOps += GetP2SHSigOpCount(tx, inputs) * WITNESS_SCALE_FACTOR;
      }
  
      for (unsigned int i = 0; i < tx.vin.size(); i++)
      {
          const CTxOut &prevout = inputs.GetOutputFor(tx.vin[i]);
          nSigOps += CountWitnessSigOps(tx.vin[i].scriptSig, prevout.scriptPubKey, i < tx.wit.vtxinwit.size() ? &tx.wit.vtxinwit[i].scriptWitness : NULL, flags);
      }
      return nSigOps;
  }
  
  bool CheckTransaction(const CTransaction& tx, CValidationState &state)
  {
  
      // Basic checks that don't depend on any context
      if (tx.vin.empty())
          return state.DoS(10, false, REJECT_INVALID, "bad-txns-vin-empty");
      if (tx.vout.empty())
          return state.DoS(10, false, REJECT_INVALID, "bad-txns-vout-empty");
      // Size limits (this doesn't take the witness into account, as that hasn't been checked for malleability)
      if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) > MAX_BLOCK_BASE_SIZE)
          return state.DoS(100, false, REJECT_INVALID, "bad-txns-oversize");
  
      // Check for negative or overflow output values
      CAmount nValueOut = 0;
      BOOST_FOREACH(const CTxOut& txout, tx.vout)
      {
          if (txout.IsEmpty() && !tx.IsCoinBase() && !tx.IsCoinStake())
              return state.DoS(100, error("CTransaction::CheckTransaction() : txout empty for user transaction"));
          if (txout.nValue < 0)
              return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative");
          if (txout.nValue > MAX_MONEY)
              return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-toolarge");
          nValueOut += txout.nValue;
          if (!MoneyRange(nValueOut))
              return state.DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge");
      }
  
      // Check for duplicate inputs
      set<COutPoint> vInOutPoints;
      BOOST_FOREACH(const CTxIn& txin, tx.vin)
      {
          if (vInOutPoints.count(txin.prevout))
              return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
          vInOutPoints.insert(txin.prevout);
      }
  
      if (tx.IsCoinBase())
      {
          if (tx.vin[0].scriptSig.size() < 2 || tx.vin[0].scriptSig.size() > 100)
              return state.DoS(100, false, REJECT_INVALID, "bad-cb-length");
      }
      else
      {
          BOOST_FOREACH(const CTxIn& txin, tx.vin)
              if (txin.prevout.IsNull())
                  return state.DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null");
      }
  
      return true;
  }
  
  void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
      int expired = pool.Expire(GetTime() - age);
      if (expired != 0)
          LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
  
      std::vector<uint256> vNoSpendsRemaining;
      pool.TrimToSize(limit, &vNoSpendsRemaining);
      BOOST_FOREACH(const uint256& removed, vNoSpendsRemaining)
          pcoinsTip->Uncache(removed);
  }
  
  /** Convert CValidationState to a human-readable message for logging */
  std::string FormatStateMessage(const CValidationState &state)
  {
      return strprintf("%s%s (code %i)",
          state.GetRejectReason(),
          state.GetDebugMessage().empty() ? "" : ", "+state.GetDebugMessage(),
          state.GetRejectCode());
  }
  
  bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree,
                                bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount& nAbsurdFee,
                                std::vector<uint256>& vHashTxnToUncache)
  {
      const uint256 hash = tx.GetHash();
      AssertLockHeld(cs_main);
      if (pfMissingInputs)
          *pfMissingInputs = false;
      if (!CheckTransaction(tx, state))
          return false; // state filled in by CheckTransaction
  
      if (IsCommunityFundEnabled(chainActive.Tip(), Params().GetConsensus()) && tx.nVersion < CTransaction::TXDZEEL_VERSION_V2)
        return state.DoS(100, false, REJECT_INVALID, "old-version");
  
      // Coinbase is only valid in a block, not as a loose transaction
      if (tx.IsCoinBase())
          return state.DoS(100, false, REJECT_INVALID, "coinbase");
  
      // Coinbase is only valid in a block, not as a loose transaction
      if (tx.IsCoinStake())
          return state.DoS(100, false, REJECT_INVALID, "coinstake");
  
      // Reject transactions with witness before segregated witness activates (override with -prematurewitness)
      bool witnessEnabled = IsWitnessEnabled(chainActive.Tip(), Params().GetConsensus());
      if (!GetBoolArg("-prematurewitness",false) && !tx.wit.IsNull() && !witnessEnabled) {
          return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
      }
  
      // Rather not work on nonstandard transactions (unless -testnet/-regtest)
      string reason;
      if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
          return state.DoS(0, false, REJECT_NONSTANDARD, reason);
  
      // Only accept nLockTime-using transactions that can be mined in the next
      // block; we don't want our mempool filled up with transactions that can't
      // be mined yet.
      if (!CheckFinalTx(tx, STANDARD_LOCKTIME_VERIFY_FLAGS))
          return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");
  
      // is it already in the memory pool?
      if (pool.exists(hash))
          return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-in-mempool");
  
      // Check for conflicts with in-memory transactions
      set<uint256> setConflicts;
      {
      LOCK(pool.cs); // protect pool.mapNextTx
      BOOST_FOREACH(const CTxIn &txin, tx.vin)
      {
          auto itConflicting = pool.mapNextTx.find(txin.prevout);
          if (itConflicting != pool.mapNextTx.end())
          {
              const CTransaction *ptxConflicting = itConflicting->second;
              if (!setConflicts.count(ptxConflicting->GetHash()))
              {
                  // Allow opt-out of transaction replacement by setting
                  // nSequence >= maxint-1 on all inputs.
                  //
                  // maxint-1 is picked to still allow use of nLockTime by
                  // non-replacable transactions. All inputs rather than just one
                  // is for the sake of multi-party protocols, where we don't
                  // want a single party to be able to disable replacement.
                  //
                  // The opt-out ignores descendants as anyone relying on
                  // first-seen mempool behavior should be checking all
                  // unconfirmed ancestors anyway; doing otherwise is hopelessly
                  // insecure.
                  bool fReplacementOptOut = true;
                  if (fEnableReplacement)
                  {
                      BOOST_FOREACH(const CTxIn &txin, ptxConflicting->vin)
                      {
                          if (txin.nSequence < std::numeric_limits<unsigned int>::max()-1)
                          {
                              fReplacementOptOut = false;
                              break;
                          }
                      }
                  }
                  if (fReplacementOptOut)
                      return state.Invalid(false, REJECT_CONFLICT, "txn-mempool-conflict");
  
                  setConflicts.insert(ptxConflicting->GetHash());
              }
          }
      }
      }
  
      {
          CCoinsView dummy;
          CCoinsViewCache view(&dummy);
  
          CAmount nValueIn = 0;
          LockPoints lp;
          {
          LOCK(pool.cs);
          CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
          view.SetBackend(viewMemPool);
  
          if (IsCommunityFundEnabled(chainActive.Tip(), Params().GetConsensus())) {
              bool fReducedQuorum = IsReducedCFundQuorumEnabled(chainActive.Tip(), Params().GetConsensus());
              int nMaxVersionProposal = fReducedQuorum ? Params().GetConsensus().nProposalMaxVersion : 2;
              int nMaxVersionPaymentRequest = fReducedQuorum ? Params().GetConsensus().nPaymentRequestMaxVersion : 2;
  
              if(tx.nVersion == CTransaction::PROPOSAL_VERSION) // Community Fund Proposal
                  if(!CFund::IsValidProposal(tx, nMaxVersionProposal))
                      return state.DoS(10, false, REJECT_INVALID, "bad-cfund-proposal");
  
              if(tx.nVersion == CTransaction::PAYMENT_REQUEST_VERSION) // Community Fund Payment Request
                  if(!CFund::IsValidPaymentRequest(tx, view, nMaxVersionPaymentRequest))
                      return state.DoS(10, false, REJECT_INVALID, "bad-cfund-payment-request");
          }
  
          // do we already have it?
          bool fHadTxInCache = pcoinsTip->HaveCoinsInCache(hash);
          if (view.HaveCoins(hash)) {
              if (!fHadTxInCache)
                  vHashTxnToUncache.push_back(hash);
              return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-known");
          }
  
          // do all inputs exist?
          // Note that this does not check for the presence of actual outputs (see the next check for that),
          // and only helps with filling in pfMissingInputs (to determine missing vs spent).
          BOOST_FOREACH(const CTxIn txin, tx.vin) {
              if (!pcoinsTip->HaveCoinsInCache(txin.prevout.hash))
                  vHashTxnToUncache.push_back(txin.prevout.hash);
              if (!view.HaveCoins(txin.prevout.hash)) {
                  if (pfMissingInputs)
                      *pfMissingInputs = true;
                  return false; // fMissingInputs and !state.IsInvalid() is used to detect this condition, don't set state.Invalid()
              }
          }
  
          // are the actual inputs available?
          if (!view.HaveInputs(tx))
              return state.Invalid(false, REJECT_DUPLICATE, "bad-txns-inputs-spent");
  
          // Bring the best block into scope
          view.GetBestBlock();
  
          nValueIn = view.GetValueIn(tx);
  
          if (!IsColdStakingEnabled(chainActive.Tip(), Params().GetConsensus()))
          {
              for (const CTxOut& txout: tx.vout)
              {
                  if(txout.scriptPubKey.IsColdStaking())
                      return state.DoS(100, false, REJECT_INVALID, "cold-staking-not-enabled");
              }
          }
  
          if(IsCommunityFundEnabled(chainActive.Tip(), Params().GetConsensus())) {
              CAmount nProposalFee = 0;
              bool fReducedQuorum = IsReducedCFundQuorumEnabled(chainActive.Tip(), Params().GetConsensus());
              int nMaxVersionProposal = fReducedQuorum ? Params().GetConsensus().nProposalMaxVersion : 2;
              int nMaxVersionPaymentRequest = fReducedQuorum ? Params().GetConsensus().nPaymentRequestMaxVersion : 2;
  
              BOOST_FOREACH(const CTxOut& vout, tx.vout)
              {
                if(vout.IsCommunityFundContribution())
                {
                  nProposalFee += vout.nValue;
                }
              }
  
              if(nProposalFee > 0 && tx.nVersion == CTransaction::PROPOSAL_VERSION && CFund::IsValidProposal(tx, nMaxVersionProposal)){
                  CFund::CProposal proposal;
                  if (TxToProposal(tx.strDZeel, tx.GetHash(), uint256(), nProposalFee, proposal))
                  {
                      viewMemPool.AddProposal(proposal);
                      LogPrint("cfund","New proposal (mempool) %s\n", proposal.ToString(view, GetTime()));
                  }
                  else
                  {
                      return state.DoS(0, false, REJECT_NONSTANDARD, "invalid proposal");
                  }
              }
  
              if(tx.nVersion == CTransaction::PAYMENT_REQUEST_VERSION && CFund::IsValidPaymentRequest(tx, view, nMaxVersionPaymentRequest)){
                  CFund::CPaymentRequest prequest;
                  if (TxToPaymentRequest(tx.strDZeel, tx.GetHash(), uint256(), prequest, view))
                  {
                      viewMemPool.AddPaymentRequest(prequest);
                      LogPrint("cfund","New payment request (mempool) %s\n", prequest.ToString());
                  }
                  else
                  {
                      return state.DoS(0, false, REJECT_NONSTANDARD, "invalid payment request");
                  }
              }
          }
  
          // we have all inputs cached now, so switch back to dummy, so we don't need to keep lock on mempool
          view.SetBackend(dummy);
  
          // Only accept BIP68 sequence locked transactions that can be mined in the next
          // block; we don't want our mempool filled up with transactions that can't
          // be mined yet.
          // Must keep pool.cs for this unless we change CheckSequenceLocks to take a
          // CoinsViewCache instead of create its own
          if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
              return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");
          }
  
          // Check for non-standard pay-to-script-hash in inputs
          if (fRequireStandard && !AreInputsStandard(tx, view))
              return state.Invalid(false, REJECT_NONSTANDARD, "bad-txns-nonstandard-inputs");
  
          int64_t nSigOpsCost = GetTransactionSigOpCost(tx, view, STANDARD_SCRIPT_VERIFY_FLAGS);
  
          CAmount nValueOut = tx.GetValueOut();
          CAmount nFees = (!tx.IsCoinStake())?nValueIn-nValueOut:0;
          // nModifiedFees includes any fee deltas from PrioritiseTransaction
          CAmount nModifiedFees = nFees;
          double nPriorityDummy = 0;
          pool.ApplyDeltas(hash, nPriorityDummy, nModifiedFees);
  
          CAmount inChainInputValue;
          double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);
  
          // Keep track of transactions that spend a coinbase, which we re-scan
          // during reorgs to ensure Params().GetConsensus().nCoinbaseMaturity is still met.
          bool fSpendsCoinbase = false;
          BOOST_FOREACH(const CTxIn &txin, tx.vin) {
              const CCoins *coins = view.AccessCoins(txin.prevout.hash);
              if (coins->IsCoinBase() || coins->IsCoinStake()) {
                  fSpendsCoinbase = true;
                  break;
              }
          }
  
          CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOpsCost, lp);
          unsigned int nSize = entry.GetTxSize();
  
          // Check that the transaction doesn't have an excessive number of
          // sigops, making it impossible to mine. Since the coinbase transaction
          // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
          // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
          // merely non-standard transaction.
          if (nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST)
              return state.DoS(0, false, REJECT_NONSTANDARD, "bad-txns-too-many-sigops", false,
                  strprintf("%d", nSigOpsCost));
  
          CAmount mempoolRejectFee = pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nSize);
          if (mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee) {
              return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
          } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) && nModifiedFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
              // Require that free transactions have sufficient priority to be mined in the next block.
              return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
          }
  
          // Continuously rate-limit free (really, very-low-fee) transactions
          // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
          // be annoying or make others' transactions take longer to confirm.
          if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize))
          {
              static CCriticalSection csFreeLimiter;
              static double dFreeCount;
              static int64_t nLastTime;
              int64_t nNow = GetTime();
  
              LOCK(csFreeLimiter);
  
              // Use an exponentially decaying ~10-minute window:
              dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
              nLastTime = nNow;
              // -limitfreerelay unit is thousand-bytes-per-minute
              // At default rate it would take over a month to fill 1GB
              if (dFreeCount + nSize >= GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) * 10 * 1000)
                  return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "rate limited free transaction");
              LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
              dFreeCount += nSize;
          }
  
          if (nAbsurdFee && nFees > nAbsurdFee)
              return state.Invalid(false,
                  REJECT_HIGHFEE, "absurdly-high-fee",
                  strprintf("%d > %d", nFees, nAbsurdFee));
  
          // Calculate in-mempool ancestors, up to a limit.
          CTxMemPool::setEntries setAncestors;
          size_t nLimitAncestors = GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
          size_t nLimitAncestorSize = GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT)*1000;
          size_t nLimitDescendants = GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
          size_t nLimitDescendantSize = GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT)*1000;
          std::string errString;
          if (!pool.CalculateMemPoolAncestors(entry, setAncestors, nLimitAncestors, nLimitAncestorSize, nLimitDescendants, nLimitDescendantSize, errString)) {
              return state.DoS(0, false, REJECT_NONSTANDARD, "too-long-mempool-chain", false, errString);
          }
  
          // A transaction that spends outputs that would be replaced by it is invalid. Now
          // that we have the set of all ancestors we can detect this
          // pathological case by making sure setConflicts and setAncestors don't
          // intersect.
          BOOST_FOREACH(CTxMemPool::txiter ancestorIt, setAncestors)
          {
              const uint256 &hashAncestor = ancestorIt->GetTx().GetHash();
              if (setConflicts.count(hashAncestor))
              {
                  return state.DoS(10, false,
                                   REJECT_INVALID, "bad-txns-spends-conflicting-tx", false,
                                   strprintf("%s spends conflicting transaction %s",
                                             hash.ToString(),
                                             hashAncestor.ToString()));
              }
          }
  
          // Check if it's economically rational to mine this transaction rather
          // than the ones it replaces.
          CAmount nConflictingFees = 0;
          size_t nConflictingSize = 0;
          uint64_t nConflictingCount = 0;
          CTxMemPool::setEntries allConflicting;
  
          // If we don't hold the lock allConflicting might be incomplete; the
          // subsequent RemoveStaged() and addUnchecked() calls don't guarantee
          // mempool consistency for us.
          LOCK(pool.cs);
          if (setConflicts.size())
          {
              CFeeRate newFeeRate(nModifiedFees, nSize);
              set<uint256> setConflictsParents;
              const int maxDescendantsToVisit = 100;
              CTxMemPool::setEntries setIterConflicting;
              BOOST_FOREACH(const uint256 &hashConflicting, setConflicts)
              {
                  CTxMemPool::txiter mi = pool.mapTx.find(hashConflicting);
                  if (mi == pool.mapTx.end())
                      continue;
  
                  // Save these to avoid repeated lookups
                  setIterConflicting.insert(mi);
  
                  // Don't allow the replacement to reduce the feerate of the
                  // mempool.
                  //
                  // We usually don't want to accept replacements with lower
                  // feerates than what they replaced as that would lower the
                  // feerate of the next block. Requiring that the feerate always
                  // be increased is also an easy-to-reason about way to prevent
                  // DoS attacks via replacements.
                  //
                  // The mining code doesn't (currently) take children into
                  // account (CPFP) so we only consider the feerates of
                  // transactions being directly replaced, not their indirect
                  // descendants. While that does mean high feerate children are
                  // ignored when deciding whether or not to replace, we do
                  // require the replacement to pay more overall fees too,
                  // mitigating most cases.
                  CFeeRate oldFeeRate(mi->GetModifiedFee(), mi->GetTxSize());
                  if (newFeeRate <= oldFeeRate)
                  {
                      return state.DoS(0, false,
                              REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                              strprintf("rejecting replacement %s; new feerate %s <= old feerate %s",
                                    hash.ToString(),
                                    newFeeRate.ToString(),
                                    oldFeeRate.ToString()));
                  }
  
                  BOOST_FOREACH(const CTxIn &txin, mi->GetTx().vin)
                  {
                      setConflictsParents.insert(txin.prevout.hash);
                  }
  
                  nConflictingCount += mi->GetCountWithDescendants();
              }
              // This potentially overestimates the number of actual descendants
              // but we just want to be conservative to avoid doing too much
              // work.
              if (nConflictingCount <= maxDescendantsToVisit) {
                  // If not too many to replace, then calculate the set of
                  // transactions that would have to be evicted
                  BOOST_FOREACH(CTxMemPool::txiter it, setIterConflicting) {
                      pool.CalculateDescendants(it, allConflicting);
                  }
                  BOOST_FOREACH(CTxMemPool::txiter it, allConflicting) {
                      nConflictingFees += it->GetModifiedFee();
                      nConflictingSize += it->GetTxSize();
                  }
              } else {
                  return state.DoS(0, false,
                          REJECT_NONSTANDARD, "too many potential replacements", false,
                          strprintf("rejecting replacement %s; too many potential replacements (%d > %d)\n",
                              hash.ToString(),
                              nConflictingCount,
                              maxDescendantsToVisit));
              }
  
              for (unsigned int j = 0; j < tx.vin.size(); j++)
              {
                  // We don't want to accept replacements that require low
                  // feerate junk to be mined first. Ideally we'd keep track of
                  // the ancestor feerates and make the decision based on that,
                  // but for now requiring all new inputs to be confirmed works.
                  if (!setConflictsParents.count(tx.vin[j].prevout.hash))
                  {
                      // Rather than check the UTXO set - potentially expensive -
                      // it's cheaper to just check if the new input refers to a
                      // tx that's in the mempool.
                      if (pool.mapTx.find(tx.vin[j].prevout.hash) != pool.mapTx.end())
                          return state.DoS(0, false,
                                           REJECT_NONSTANDARD, "replacement-adds-unconfirmed", false,
                                           strprintf("replacement %s adds unconfirmed input, idx %d",
                                                    hash.ToString(), j));
                  }
              }
  
              // The replacement must pay greater fees than the transactions it
              // replaces - if we did the bandwidth used by those conflicting
              // transactions would not be paid for.
              if (nModifiedFees < nConflictingFees)
              {
                  return state.DoS(0, false,
                                   REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                                   strprintf("rejecting replacement %s, less fees than conflicting txs; %s < %s",
                                            hash.ToString(), FormatMoney(nModifiedFees), FormatMoney(nConflictingFees)));
              }
  
              // Finally in addition to paying more fees than the conflicts the
              // new transaction must pay for its own bandwidth.
              CAmount nDeltaFees = nModifiedFees - nConflictingFees;
              if (nDeltaFees < ::minRelayTxFee.GetFee(nSize))
              {
                  return state.DoS(0, false,
                          REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                          strprintf("rejecting replacement %s, not enough additional fees to relay; %s < %s",
                                hash.ToString(),
                                FormatMoney(nDeltaFees),
                                FormatMoney(::minRelayTxFee.GetFee(nSize))));
              }
          }
  
          unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
          if (!Params().RequireStandard()) {
              scriptVerifyFlags = GetArg("-promiscuousmempoolflags", scriptVerifyFlags);
          }
  
          // Check against previous transactions
          // This is done last to help prevent CPU exhaustion denial-of-service attacks.
          PrecomputedTransactionData txdata(tx);
          if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, txdata)) {
              // SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we
              // need to turn both off, and compare against just turning off CLEANSTACK
              // to see if the failure is specifically due to witness validation.
              if (CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, txdata) &&
                  !CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, txdata)) {
                  // Only the witness is wrong, so the transaction itself may be fine.
                  state.SetCorruptionPossible();
              }
              return false;
          }
  
          // Check again against just the consensus-critical mandatory script
          // verification flags, in case of bugs in the standard flags that cause
          // transactions to pass as valid when they're actually invalid. For
          // instance the STRICTENC flag was incorrectly allowing certain
          // CHECKSIG NOT scripts to pass, even though they were invalid.
          //
          // There is a similar check in CreateNewBlock() to prevent creating
          // invalid blocks, however allowing such transactions into the mempool
          // can be exploited as a DoS attack.
          if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, txdata))
          {
              return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
                  __func__, hash.ToString(), FormatStateMessage(state));
          }
  
          // Remove conflicting transactions from the mempool
          BOOST_FOREACH(const CTxMemPool::txiter it, allConflicting)
          {
              LogPrint("mempool", "replacing tx %s with %s for %s BTC additional fees, %d delta bytes\n",
                      it->GetTx().GetHash().ToString(),
                      hash.ToString(),
                      FormatMoney(nModifiedFees - nConflictingFees),
                      (int)nSize - (int)nConflictingSize);
          }
          pool.RemoveStaged(allConflicting, false);
  
          // Store transaction in memory
          pool.addUnchecked(hash, entry, setAncestors, !IsInitialBlockDownload());
  
          // Add memory address index
          if (fAddressIndex) {
              pool.addAddressIndex(entry, view);
          }
  
          // Add memory spent index
          if (fSpentIndex) {
              pool.addSpentIndex(entry, view);
          }
  
          // trim mempool and check if tx was trimmed
          if (!fOverrideMempoolLimit) {
              LimitMempoolSize(pool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
              if (!pool.exists(hash))
                  return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
          }
      }
  
      SyncWithWallets(tx, NULL, NULL);
  
      return true;
  }
  
  bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
                          bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount nAbsurdFee)
  {
      std::vector<uint256> vHashTxToUncache;
      bool res = AcceptToMemoryPoolWorker(pool, state, tx, fLimitFree, pfMissingInputs, fOverrideMempoolLimit, nAbsurdFee, vHashTxToUncache);
      if (!res) {
          BOOST_FOREACH(const uint256& hashTx, vHashTxToUncache)
              pcoinsTip->Uncache(hashTx);
      }
      return res;
  }
  
  bool GetTimestampIndex(const unsigned int &high, const unsigned int &low, const bool fActiveOnly, std::vector<std::pair<uint256, unsigned int> > &hashes)
  {
      if (!fTimestampIndex)
          return error("Timestamp index not enabled");
  
      if (!pblocktree->ReadTimestampIndex(high, low, fActiveOnly, hashes))
          return error("Unable to get hashes for timestamps");
  
      return true;
  }
  
  bool GetSpentIndex(CSpentIndexKey &key, CSpentIndexValue &value)
  {
      if (!fSpentIndex)
          return false;
  
      if (mempool.getSpentIndex(key, value))
          return true;
  
      if (!pblocktree->ReadSpentIndex(key, value))
          return false;
  
      return true;
  }
  
  bool HashOnchainActive(const uint256 &hash)
  {
      CBlockIndex* pblockindex = mapBlockIndex[hash];
  
      if (!chainActive.Contains(pblockindex)) {
          return false;
      }
  
      return true;
  }
  
  bool GetAddressIndex(uint160 addressHash, int type,
                       std::vector<std::pair<CAddressIndexKey, CAmount> > &addressIndex, int start, int end)
  {
      if (!fAddressIndex)
          return error("address index not enabled");
  
      if (!pblocktree->ReadAddressIndex(addressHash, type, addressIndex, start, end))
          return error("unable to get txids for address");
  
      return true;
  }
  
  bool GetAddressUnspent(uint160 addressHash, int type,
                         std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > &unspentOutputs)
  {
      if (!fAddressIndex)
          return error("address index not enabled");
  
      if (!pblocktree->ReadAddressUnspentIndex(addressHash, type, unspentOutputs))
          return error("unable to get txids for address");
  
      return true;
  }
  
  /** Return transaction in tx, and if it was found inside a block, its hash is placed in hashBlock */
  bool GetTransaction(const uint256 &hash, CTransaction &txOut, const Consensus::Params& consensusParams, uint256 &hashBlock, bool fAllowSlow)
  {
  
      CBlockIndex *pindexSlow = NULL;
  
      LOCK(cs_main);
  
      std::shared_ptr<const CTransaction> ptx = mempool.get(hash);
      if (ptx)
      {
          txOut = *ptx;
          return true;
      }
  
      if (fTxIndex) {
          CDiskTxPos postx;
          if (pblocktree->ReadTxIndex(hash, postx)) {
              CAutoFile file(OpenBlockFile(postx, true), SER_DISK, CLIENT_VERSION);
              if (file.IsNull())
                  return error("%s: OpenBlockFile failed", __func__);
              CBlockHeader header;
              try {
                  file >> header;
                  fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                  file >> txOut;
              } catch (const std::exception& e) {
                  return error("%s: Deserialize or I/O error - %s", __func__, e.what());
              }
              hashBlock = header.GetHash();
              if (txOut.GetHash() != hash)
                  return error("%s: txid mismatch", __func__);
              return true;
          }
      }
  
      if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
          int nHeight = -1;
          {
              const CCoinsViewCache& view = *pcoinsTip;
              const CCoins* coins = view.AccessCoins(hash);
              if (coins)
                  nHeight = coins->nHeight;
          }
          if (nHeight > 0)
              pindexSlow = chainActive[nHeight];
      }
  
      if (pindexSlow) {
          CBlock block;
          if (ReadBlockFromDisk(block, pindexSlow, consensusParams)) {
              BOOST_FOREACH(const CTransaction &tx, block.vtx) {
                  if (tx.GetHash() == hash) {
                      txOut = tx;
                      hashBlock = pindexSlow->GetBlockHash();
                      return true;
                  }
              }
          }
      }
  
      return false;
  }
  
  
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // CBlock and CBlockIndex
  //
  
  bool WriteBlockToDisk(const CBlock& block, CDiskBlockPos& pos, const CMessageHeader::MessageStartChars& messageStart)
  {
      // Open history file to append
      CAutoFile fileout(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
      if (fileout.IsNull())
          return error("WriteBlockToDisk: OpenBlockFile failed");
  
      // Write index header
      unsigned int nSize = fileout.GetSerializeSize(block);
      fileout << FLATDATA(messageStart) << nSize;
  
      // Write block
      long fileOutPos = ftell(fileout.Get());
      if (fileOutPos < 0)
          return error("WriteBlockToDisk: ftell failed");
      pos.nPos = (unsigned int)fileOutPos;
      fileout << block;
  
      return true;
  }
  
  bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams)
  {
      block.SetNull();
  
      // Open history file to read
      CAutoFile filein(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION);
      if (filein.IsNull())
          return error("ReadBlockFromDisk: OpenBlockFile failed for %s", pos.ToString());
  
      // Read block
      try {
          filein >> block;
      }
      catch (const std::exception& e) {
          return error("%s: Deserialize or I/O error - %s at %s", __func__, e.what(), pos.ToString());
      }
  
      return true;
  }
  
  bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
  {
      if (!ReadBlockFromDisk(block, pindex->GetBlockPos(), consensusParams))
          return false;
      if (block.GetHash() != pindex->GetBlockHash())
          return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() doesn't match index for %s at %s",
                  pindex->ToString(), pindex->GetBlockPos().ToString());
      return true;
  }
  
  CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams)
  {
  
      if (nHeight == 1)
      {
          CAmount nSubsidy = 1000000 * COIN;
          return nSubsidy;
      }
  
      if (nHeight <= Params().GetConsensus().nLastPOWBlock)
          return CAmount(50 * COIN);
  
      return 0;
  }
  
  bool IsInitialBlockDownload()
  {
      const CChainParams& chainParams = Params();
  
      // Once this function has returned false, it must remain false.
      static std::atomic<bool> latchToFalse{false};
      // Optimization: pre-test latch before taking the lock.
      if (latchToFalse.load(std::memory_order_relaxed))
          return false;
  
      LOCK(cs_main);
      if (latchToFalse.load(std::memory_order_relaxed))
          return false;
      if (fImporting || fReindex)
          return true;
      if (fCheckpointsEnabled && chainActive.Height() < Checkpoints::GetTotalBlocksEstimate(chainParams.Checkpoints()))
          return true;
      bool state = (chainActive.Height() < pindexBestHeader->nHeight - 24 * 6 ||
              std::max(chainActive.Tip()->GetBlockTime(), pindexBestHeader->GetBlockTime()) < GetTime() - nMaxTipAge);
      if (!state)
          latchToFalse.store(true, std::memory_order_relaxed);
      return state;
  }
  
  bool fLargeWorkForkFound = false;
  bool fLargeWorkInvalidChainFound = false;
  CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;
  
  void CheckForkWarningConditions()
  {
      AssertLockHeld(cs_main);
      // Before we get past initial download, we cannot reliably alert about forks
      // (we assume we don't get stuck on a fork before the last checkpoint)
      if (IsInitialBlockDownload())
          return;
  
      // If our best fork is no longer within 72 blocks (+/- 12 hours if no one mines it)
      // of our head, drop it
      if (pindexBestForkTip && chainActive.Height() - pindexBestForkTip->nHeight >= 72)
          pindexBestForkTip = NULL;
  
      if (pindexBestForkTip || (pindexBestInvalid && pindexBestInvalid->nChainWork > chainActive.Tip()->nChainWork + (GetBlockProof(*chainActive.Tip()) * 6)))
      {
          if (!fLargeWorkForkFound && pindexBestForkBase)
          {
              std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                  pindexBestForkBase->phashBlock->ToString() + std::string("'");
              AlertNotify(warning);
          }
          if (pindexBestForkTip && pindexBestForkBase)
          {
              LogPrintf("%s: Warning: Large valid fork found\n  forking the chain at height %d (%s)\n  lasting to height %d (%s).\nChain state database corruption likely.\n", __func__,
                     pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString(),
                     pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString());
              fLargeWorkForkFound = true;
          }
          else
          {
              LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__);
              fLargeWorkInvalidChainFound = true;
          }
      }
      else
      {
          fLargeWorkForkFound = false;
          fLargeWorkInvalidChainFound = false;
      }
  }
  
  void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
  {
      AssertLockHeld(cs_main);
      // If we are on a fork that is sufficiently large, set a warning flag
      CBlockIndex* pfork = pindexNewForkTip;
      CBlockIndex* plonger = chainActive.Tip();
      while (pfork && pfork != plonger)
      {
          while (plonger && plonger->nHeight > pfork->nHeight)
              plonger = plonger->pprev;
          if (pfork == plonger)
              break;
          pfork = pfork->pprev;
      }
  
      // We define a condition where we should warn the user about as a fork of at least 7 blocks
      // with a tip within 72 blocks (+/- 12 hours if no one mines it) of ours
      // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
      // hash rate operating on the fork.
      // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
      // We define it this way because it allows us to only store the highest fork tip (+ base) which meets
      // the 7-block condition and from this always have the most-likely-to-cause-warning fork
      if (pfork && (!pindexBestForkTip || (pindexBestForkTip && pindexNewForkTip->nHeight > pindexBestForkTip->nHeight)) &&
              pindexNewForkTip->nChainWork - pfork->nChainWork > (GetBlockProof(*pfork) * 7) &&
              chainActive.Height() - pindexNewForkTip->nHeight < 72)
      {
          pindexBestForkTip = pindexNewForkTip;
          pindexBestForkBase = pfork;
      }
  
      CheckForkWarningConditions();
  }
  
  // Requires cs_main.
  void Misbehaving(NodeId pnode, int howmuch)
  {
      if (howmuch == 0)
          return;
  
      CNodeState *state = State(pnode);
      if (state == NULL)
          return;
  
      state->nMisbehavior += howmuch;
      int banscore = GetArg("-banscore", DEFAULT_BANSCORE_THRESHOLD);
      if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore)
      {
          LogPrintf("%s: %s (%d -> %d) BAN THRESHOLD EXCEEDED\n", __func__, state->name, state->nMisbehavior-howmuch, state->nMisbehavior);
          state->fShouldBan = true;
      } else
          LogPrintf("%s: %s (%d -> %d)\n", __func__, state->name, state->nMisbehavior-howmuch, state->nMisbehavior);
  }
  
  void static InvalidChainFound(CBlockIndex* pindexNew)
  {
      if (!pindexBestInvalid || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
          pindexBestInvalid = pindexNew;
  
      LogPrintf("%s: invalid block=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
        pindexNew->GetBlockHash().ToString(), pindexNew->nHeight,
        log(pindexNew->nChainWork.getdouble())/log(2.0), DateTimeStrFormat("%Y-%m-%d %H:%M:%S",
        pindexNew->GetBlockTime()));
      CBlock block;
      CBlockIndex *tip = chainActive.Tip();
      assert (tip);
      if (ReadBlockFromDisk(block, pindexNew, Params().GetConsensus())) {
          BOOST_FOREACH(const CTransaction &tx, block.vtx) {
              SyncWithWallets(tx, tip, NULL, false);
          }
      }
      LogPrintf("%s:  current best=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
        tip->GetBlockHash().ToString(), chainActive.Height(), log(tip->nChainWork.getdouble())/log(2.0),
        DateTimeStrFormat("%Y-%m-%d %H:%M:%S", tip->GetBlockTime()));
      CheckForkWarningConditions();
  }
  
  void static InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state) {
      int nDoS = 0;
      if (state.IsInvalid(nDoS)) {
          std::map<uint256, NodeId>::iterator it = mapBlockSource.find(pindex->GetBlockHash());
          if (it != mapBlockSource.end() && State(it->second)) {
              assert (state.GetRejectCode() < REJECT_INTERNAL); // Blocks are never rejected with internal reject codes
              CBlockReject reject = {(unsigned char)state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), pindex->GetBlockHash()};
              State(it->second)->rejects.push_back(reject);
              if (nDoS > 0)
                  Misbehaving(it->second, nDoS);
          }
      }
      if (!state.CorruptionPossible()) {
          pindex->nStatus |= BLOCK_FAILED_VALID;
          setDirtyBlockIndex.insert(pindex);
          setBlockIndexCandidates.erase(pindex);
          InvalidChainFound(pindex);
      }
  }
  
  void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight)
  {
      // mark inputs spent
      if (!tx.IsCoinBase()) {
          txundo.vprevout.reserve(tx.vin.size());
          BOOST_FOREACH(const CTxIn &txin, tx.vin) {
              CCoinsModifier coins = inputs.ModifyCoins(txin.prevout.hash);
              unsigned nPos = txin.prevout.n;
  
              if (nPos >= coins->vout.size() || coins->vout[nPos].IsNull())
                  assert(false);
              // mark an outpoint spent, and construct undo information
              txundo.vprevout.push_back(CTxInUndo(coins->vout[nPos]));
              coins->Spend(nPos);
              if (coins->vout.size() == 0) {
                  CTxInUndo& undo = txundo.vprevout.back();
                  undo.nHeight = coins->nHeight;
                  undo.fCoinBase = coins->fCoinBase;
                  undo.nVersion = coins->nVersion;
              }
          }
      }
      // add outputs
      inputs.ModifyNewCoins(tx.GetHash(), tx.IsCoinBase())->FromTx(tx, nHeight);
  }
  
  void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight)
  {
      CTxUndo txundo;
      UpdateCoins(tx, inputs, txundo, nHeight);
  }
  
  bool CScriptCheck::operator()() {
      const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
      const CScriptWitness *witness = (nIn < ptxTo->wit.vtxinwit.size()) ? &ptxTo->wit.vtxinwit[nIn].scriptWitness : NULL;
  
      if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore, *txdata), &error)) {
          return false;
      }
      return true;
  }
  
  int GetSpendHeight(const CCoinsViewCache& inputs)
  {
      LOCK(cs_main);
      CBlockIndex* pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
      return pindexPrev->nHeight + 1;
  }
  
  namespace Consensus {
  bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight)
  {
          // This doesn't trigger the DoS code on purpose; if it did, it would make it easier
          // for an attacker to attempt to split the network.
          if (!inputs.HaveInputs(tx))
              return state.Invalid(false, 0, "", "Inputs unavailable");
          CAmount nValueIn = 0;
          CAmount nFees = 0;
          for (unsigned int i = 0; i < tx.vin.size(); i++)
          {
              const COutPoint &prevout = tx.vin[i].prevout;
              const CCoins *coins = inputs.AccessCoins(prevout.hash);
              assert(coins);
  
              // If prev is coinbase, check that it's matured
              if ((coins->IsCoinBase() || coins->IsCoinStake()) && !GetBoolArg("-testnet",false)) {
                  if (nSpendHeight - coins->nHeight < ::Params().GetConsensus().nCoinbaseMaturity && nSpendHeight - coins->nHeight > 0)
                      return state.Invalid(false,
                          REJECT_INVALID, "bad-txns-premature-spend-of-coinbase",
                          strprintf("tried to spend %s at depth %d", coins->IsCoinBase() ?"coinbase":"coinstake",nSpendHeight - coins->nHeight));
              }
  
              // Check for negative or overflow input values
              nValueIn += coins->vout[prevout.n].nValue;
              if (!MoneyRange(coins->vout[prevout.n].nValue) || !MoneyRange(nValueIn))
                  return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputvalues-outofrange");
  
          }
  
          if(!tx.IsCoinBase() && !tx.IsCoinStake()){
            if (nValueIn < tx.GetValueOut())
                return state.DoS(100, false, REJECT_INVALID, "bad-txns-in-belowout", false,
                    strprintf("value in (%s) < value out (%s)", FormatMoney(nValueIn), FormatMoney(tx.GetValueOut())));
  
            // Tally transaction fees
            CAmount nTxFee = nValueIn - tx.GetValueOut();
            if (nTxFee < 0)
                return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-negative");
            nFees += nTxFee;
            if (!MoneyRange(nFees))
                return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-outofrange");
          }
  
  
      return true;
  }
  }// namespace Consensus
  
  bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks)
  {
      if (!tx.IsCoinBase())
      {
          if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs)))
              return false;
  
          if (pvChecks)
              pvChecks->reserve(tx.vin.size());
  
          // The first loop above does all the inexpensive checks.
          // Only if ALL inputs pass do we perform expensive ECDSA signature checks.
          // Helps prevent CPU exhaustion attacks.
  
          // Skip ECDSA signature verification when connecting blocks before the
          // last block chain checkpoint. Assuming the checkpoints are valid this
          // is safe because block merkle hashes are still computed and checked,
          // and any change will be caught at the next checkpoint. Of course, if
          // the checkpoint is for a chain that's invalid due to false scriptSigs
          // this optimisation would allow an invalid chain to be accepted.
          if (fScriptChecks) {
              for (unsigned int i = 0; i < tx.vin.size(); i++) {
                  const COutPoint &prevout = tx.vin[i].prevout;
                  const CCoins* coins = inputs.AccessCoins(prevout.hash);
                  assert(coins);
  
                  CTransaction txPrev;
                  uint256 hashBlock = uint256();
                  int valid = 1;
  
                  if (!GetTransaction(prevout.hash, txPrev, Params().GetConsensus(), hashBlock, true))
                     valid = 0;
  
                  if (mapBlockIndex.count(hashBlock) == 0)
                     valid = 0;
  
                  if(valid){ // prev out is already checked in CheckTxInputs
                      CBlockIndex* pblockindex = mapBlockIndex[hashBlock];
  
                      // ppcoin: check transaction timestamp
                      if (txPrev.nTime > tx.nTime && pblockindex->nHeight > 1294597)
                          return state.DoS(100, false, REJECT_INVALID, "tx-timestamp-earlier-as-output");
                  }
  
                  // Verify signature
                  CScriptCheck check(*coins, tx, i, flags, cacheStore, &txdata);
                  if (pvChecks) {
                      pvChecks->push_back(CScriptCheck());
                      check.swap(pvChecks->back());
                  } else if (!check()) {
                      if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) {
                          // Check whether the failure was caused by a
                          // non-mandatory script verification check, such as
                          // non-standard DER encodings or non-null dummy
                          // arguments; if so, don't trigger DoS protection to
                          // avoid splitting the network between upgraded and
                          // non-upgraded nodes.
                          CScriptCheck check2(*coins, tx, i,
                                  flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore, &txdata);
                          if (check2())
                              return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
                      }
                      // Failures of other flags indicate a transaction that is
                      // invalid in new blocks, e.g. a invalid P2SH. We DoS ban
                      // such nodes as they are not following the protocol. That
                      // said during an upgrade careful thought should be taken
                      // as to the correct behavior - we may want to continue
                      // peering with non-upgraded nodes even after soft-fork
                      // super-majority signaling has occurred.
                      return state.DoS(100,false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError())));
                  }
              }
          }
      }
  
      return true;
  }
  
  namespace {
  
  bool UndoWriteToDisk(const CBlockUndo& blockundo, CDiskBlockPos& pos, const uint256& hashBlock, const CMessageHeader::MessageStartChars& messageStart)
  {
      // Open history file to append
      CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
      if (fileout.IsNull())
          return error("%s: OpenUndoFile failed", __func__);
  
      // Write index header
      unsigned int nSize = fileout.GetSerializeSize(blockundo);
      fileout << FLATDATA(messageStart) << nSize;
  
      // Write undo data
      long fileOutPos = ftell(fileout.Get());
      if (fileOutPos < 0)
          return error("%s: ftell failed", __func__);
      pos.nPos = (unsigned int)fileOutPos;
      fileout << blockundo;
  
      // calculate & write checksum
      CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
      hasher << hashBlock;
      hasher << blockundo;
      fileout << hasher.GetHash();
  
      return true;
  }
  
  bool UndoReadFromDisk(CBlockUndo& blockundo, const CDiskBlockPos& pos, const uint256& hashBlock)
  {
      // Open history file to read
      CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
      if (filein.IsNull())
          return error("%s: OpenBlockFile failed", __func__);
  
      // Read block
      uint256 hashChecksum;
      try {
          filein >> blockundo;
          filein >> hashChecksum;
      }
      catch (const std::exception& e) {
          return error("%s: Deserialize or I/O error - %s", __func__, e.what());
      }
  
      // Verify checksum
      CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
      hasher << hashBlock;
      hasher << blockundo;
      if (hashChecksum != hasher.GetHash())
          return error("%s: Checksum mismatch", __func__);
  
      return true;
  }
  
  /** Abort with a message */
  bool AbortNode(const std::string& strMessage, const std::string& userMessage="")
  {
      strMiscWarning = strMessage;
      LogPrintf("*** %s\n", strMessage);
      uiInterface.ThreadSafeMessageBox(
          userMessage.empty() ? _("Error: A fatal internal error occurred, see debug.log for details") : userMessage,
          "", CClientUIInterface::MSG_ERROR);
      StartShutdown();
      return false;
  }
  
  bool AbortNode(CValidationState& state, const std::string& strMessage, const std::string& userMessage="")
  {
      AbortNode(strMessage, userMessage);
      return state.Error(strMessage);
  }
  
  } // anon namespace
  
  /**
   * Apply the undo operation of a CTxInUndo to the given chain state.
   * @param undo The undo object.
   * @param view The coins view to which to apply the changes.
   * @param out The out point that corresponds to the tx input.
   * @return True on success.
   */
  static bool ApplyTxInUndo(const CTxInUndo& undo, CCoinsViewCache& view, const COutPoint& out)
  {
      bool fClean = true;
  
      CCoinsModifier coins = view.ModifyCoins(out.hash);
      if (undo.nHeight != 0) {
          // undo data contains height: this is the last output of the prevout tx being spent
          if (!coins->IsPruned())
              fClean = fClean && error("%s: undo data overwriting existing transaction", __func__);
          coins->Clear();
          coins->fCoinBase = undo.fCoinBase;
          coins->nHeight = undo.nHeight;
          coins->nVersion = undo.nVersion;
      } else {
          if (coins->IsPruned())
              fClean = fClean && error("%s: undo data adding output to missing transaction", __func__);
      }
      if (coins->IsAvailable(out.n))
          fClean = fClean && error("%s: undo data overwriting existing output", __func__);
      if (coins->vout.size() < out.n+1)
          coins->vout.resize(out.n+1);
      coins->vout[out.n] = undo.txout;
  
      return fClean;
  }
  
  bool DisconnectBlock(const CBlock& block, CValidationState& state, const CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
  {
      assert(pindex->GetBlockHash() == view.GetBestBlock());
  
      if (pfClean)
          *pfClean = false;
  
      bool fClean = true;
  
      CBlockUndo blockUndo;
      CDiskBlockPos pos = pindex->GetUndoPos();
      if (pos.IsNull())
          return error("DisconnectBlock(): no undo data available");
      if (!UndoReadFromDisk(blockUndo, pos, pindex->pprev->GetBlockHash()))
          return error("DisconnectBlock(): failure reading undo data");
  
      if (blockUndo.vtxundo.size() + 1 != block.vtx.size())
          return error("DisconnectBlock(): block and undo data inconsistent");
  
      std::vector<std::pair<CAddressIndexKey, CAmount> > addressIndex;
      std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > addressUnspentIndex;
      std::vector<std::pair<CSpentIndexKey, CSpentIndexValue> > spentIndex;
  
      // undo transactions in reverse order
      for (int i = block.vtx.size() - 1; i >= 0; i--) {
          const CTransaction &tx = block.vtx[i];
          uint256 hash = tx.GetHash();
  
          if(IsCommunityFundEnabled(pindex->pprev, Params().GetConsensus())) {
              bool fReducedQuorum = IsReducedCFundQuorumEnabled(chainActive.Tip(), Params().GetConsensus());
              int nMaxVersionProposal = fReducedQuorum ? Params().GetConsensus().nProposalMaxVersion : 2;
              int nMaxVersionPaymentRequest = fReducedQuorum ? Params().GetConsensus().nPaymentRequestMaxVersion : 2;
  
              if(tx.nVersion == CTransaction::PROPOSAL_VERSION && CFund::IsValidProposal(tx, nMaxVersionProposal)) {
                  view.RemoveProposal(hash);
              }
  
              if(tx.nVersion == CTransaction::PAYMENT_REQUEST_VERSION && CFund::IsValidPaymentRequest(tx, view, nMaxVersionPaymentRequest)) {
                  view.RemovePaymentRequest(hash);
              }
          }
  
          if (fAddressIndex)
          {
              for (unsigned int k = tx.vout.size(); k-- > 0;) {
                  const CTxOut &out = tx.vout[k];
  
                  if (out.scriptPubKey.IsPayToScriptHash()) {
                      vector<unsigned char> hashBytes(out.scriptPubKey.begin()+2, out.scriptPubKey.begin()+22);
  
                      // undo receiving activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(2, uint160(hashBytes), pindex->nHeight, i, hash, k, false), out.nValue));
  
                      // undo unspent index
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(2, uint160(hashBytes), hash, k), CAddressUnspentValue()));
  
  
                  }  else if (out.scriptPubKey.IsPayToPublicKey() || out.scriptPubKey.IsColdStaking()) {
                      uint160 hashBytes;
                      int type = 0;
                      CTxDestination destination;
                      ExtractDestination(out.scriptPubKey, destination);
                      CNavCoinAddress address(destination);
                      if (out.scriptPubKey.IsColdStaking())
                          address.GetSpendingAddress(address);
                      address.GetIndexKey(hashBytes, type);
  
                      // undo spending activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(type, uint160(hashBytes), pindex->nHeight, i, hash, k, true), out.nValue));
  
                      // restore unspent index
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(type, uint160(hashBytes), hash, k), CAddressUnspentValue()));
  
  
                  } else if (out.scriptPubKey.IsPayToPublicKeyHash()) {
                      vector<unsigned char> hashBytes(out.scriptPubKey.begin()+3, out.scriptPubKey.begin()+23);
  
                      // undo receiving activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(1, uint160(hashBytes), pindex->nHeight, i, hash, k, false), out.nValue));
  
                      // undo unspent index
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(1, uint160(hashBytes), hash, k), CAddressUnspentValue()));
  
                  } else {
                      continue;
                  }
  
              }
  
          }
  
          // Check that all outputs are available and match the outputs in the block itself
          // exactly.
          {
          CCoinsModifier outs = view.ModifyCoins(hash);
          outs->ClearUnspendable();
  
          CCoins outsBlock(tx, pindex->nHeight);
          // The CCoins serialization does not serialize negative numbers.
          // No network rules currently depend on the version here, so an inconsistency is harmless
          // but it must be corrected before txout nversion ever influences a network rule.
          if (outsBlock.nVersion < 0)
              outs->nVersion = outsBlock.nVersion;
  
          if (*outs != outsBlock)
              fClean = fClean && error("DisconnectBlock(): added transaction mismatch? database corrupted");
  
          // remove outputs
          outs->Clear();
          }
  
          // restore inputs
          if (i > 0) { // not coinbases
              const CTxUndo &txundo = blockUndo.vtxundo[i-1];
              if (txundo.vprevout.size() != tx.vin.size())
                  return error("DisconnectBlock(): transaction and undo data inconsistent");
              for (unsigned int j = tx.vin.size(); j-- > 0;) {
                  const COutPoint &out = tx.vin[j].prevout;
                  const CTxInUndo &undo = txundo.vprevout[j];
                  if (!ApplyTxInUndo(undo, view, out))
                      fClean = false;
  
                  const CTxIn input = tx.vin[j];
  
                  if (fSpentIndex) {
                      // undo and delete the spent index
                      spentIndex.push_back(make_pair(CSpentIndexKey(input.prevout.hash, input.prevout.n), CSpentIndexValue()));
                  }
  
                  if (fAddressIndex) {
                      const CTxOut &prevout = view.GetOutputFor(tx.vin[j]);
                      if (prevout.scriptPubKey.IsPayToScriptHash()) {
                          vector<unsigned char> hashBytes(prevout.scriptPubKey.begin()+2, prevout.scriptPubKey.begin()+22);
  
                          // undo spending activity
                          addressIndex.push_back(make_pair(CAddressIndexKey(2, uint160(hashBytes), pindex->nHeight, i, hash, j, true), prevout.nValue * -1));
  
                          // restore unspent index
                          addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(2, uint160(hashBytes), input.prevout.hash, input.prevout.n), CAddressUnspentValue(prevout.nValue, prevout.scriptPubKey, undo.nHeight)));
  
  
                      } else if (prevout.scriptPubKey.IsPayToPublicKey() || prevout.scriptPubKey.IsColdStaking()) {
                          uint160 hashBytes;
                          int type = 0;
                          CTxDestination destination;
                          ExtractDestination(prevout.scriptPubKey, destination);
                          CNavCoinAddress address(destination);
                          if (prevout.scriptPubKey.IsColdStaking())
                              address.GetSpendingAddress(address);
                          address.GetIndexKey(hashBytes, type);
  
                          // undo spending activity
                          addressIndex.push_back(make_pair(CAddressIndexKey(type, uint160(hashBytes), pindex->nHeight, i, hash, j, true), prevout.nValue * -1));
  
                          // restore unspent index
                          addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(type, uint160(hashBytes), input.prevout.hash, input.prevout.n), CAddressUnspentValue(prevout.nValue, prevout.scriptPubKey, undo.nHeight)));
  
  
                      } else if (prevout.scriptPubKey.IsPayToPublicKeyHash()) {
                          vector<unsigned char> hashBytes(prevout.scriptPubKey.begin()+3, prevout.scriptPubKey.begin()+23);
  
                          // undo spending activity
                          addressIndex.push_back(make_pair(CAddressIndexKey(1, uint160(hashBytes), pindex->nHeight, i, hash, j, true), prevout.nValue * -1));
  
                          // restore unspent index
                          addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(1, uint160(hashBytes), input.prevout.hash, input.prevout.n), CAddressUnspentValue(prevout.nValue, prevout.scriptPubKey, undo.nHeight)));
  
                      } else {
                          continue;
                      }
                  }
  
              }
          }
      }
  
      std::map<uint256, bool> vSeen;
  
      for(unsigned int i = 0; i < pindex->vProposalVotes.size(); i++)
      {
          if(!view.HaveProposal(pindex->vProposalVotes[i].first))
              continue;
  
          CProposalModifier proposal = view.ModifyProposal(pindex->vProposalVotes[i].first);
  
          if(vSeen.count(proposal->hash) == 0)
          {
              if(pindex->vProposalVotes[i].second)
                  proposal->nVotesYes = max(proposal->nVotesYes - 1, 0);
              else
                  proposal->nVotesNo = max(proposal->nVotesNo - 1, 0);
  
              vSeen[pindex->vProposalVotes[i].first]=true;
          }
      }
  
      for(unsigned int i = 0; i < pindex->vPaymentRequestVotes.size(); i++)
      {
          if(!view.HavePaymentRequest(pindex->vPaymentRequestVotes[i].first))
              continue;
  
          CPaymentRequestModifier prequest = view.ModifyPaymentRequest(pindex->vPaymentRequestVotes[i].first);
          CFund::CProposal proposal;
  
          if(!view.GetProposal(prequest->proposalhash, proposal))
              continue;
  
          if (mapBlockIndex.count(proposal.blockhash) == 0)
              continue;
  
          CBlockIndex* pindexblockparent = mapBlockIndex[proposal.blockhash];
  
          if(pindexblockparent == NULL)
              continue;
  
          if(vSeen.count(prequest->hash) == 0)
          {
              if(pindex->vPaymentRequestVotes[i].second)
                  prequest->nVotesYes = max(prequest->nVotesYes - 1, 0);
              else
                  prequest->nVotesNo = max(prequest->nVotesNo - 1, 0);
  
              vSeen[pindex->vPaymentRequestVotes[i].first]=true;
          }
      }
  
      // move best block pointer to prevout block
      view.SetBestBlock(pindex->pprev->GetBlockHash());
  
      if (pfClean) {
          *pfClean = fClean;
          return true;
      }
  
      if (fAddressIndex) {
          if (!pblocktree->EraseAddressIndex(addressIndex)) {
              return AbortNode(state, "Failed to delete address index");
          }
          if (!pblocktree->UpdateAddressUnspentIndex(addressUnspentIndex)) {
              return AbortNode(state, "Failed to write address unspent index");
          }
      }
  
      return fClean;
  }
  
  void static FlushBlockFile(bool fFinalize = false)
  {
      LOCK(cs_LastBlockFile);
  
      CDiskBlockPos posOld(nLastBlockFile, 0);
  
      FILE *fileOld = OpenBlockFile(posOld);
      if (fileOld) {
          if (fFinalize)
              TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nSize);
          FileCommit(fileOld);
          fclose(fileOld);
      }
  
      fileOld = OpenUndoFile(posOld);
      if (fileOld) {
          if (fFinalize)
              TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nUndoSize);
          FileCommit(fileOld);
          fclose(fileOld);
      }
  }
  
  bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigned int nAddSize);
  
  static CCheckQueue<CScriptCheck> scriptcheckqueue(128);
  
  void ThreadScriptCheck() {
      RenameThread("navcoin-scriptch");
      scriptcheckqueue.Thread();
  }
  
  // Protected by cs_main
  VersionBitsCache versionbitscache;
  
  int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      int32_t nVersion = IsSigHFEnabled(Params().GetConsensus(), pindexPrev) ? VERSIONBITS_TOP_BITS_SIG : VERSIONBITS_TOP_BITS;
  
      for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
          ThresholdState state = VersionBitsState(pindexPrev, params, (Consensus::DeploymentPos)i, versionbitscache);
          if ((state == THRESHOLD_LOCKED_IN || state == THRESHOLD_ACTIVE  ||
               (state == THRESHOLD_STARTED && !IsVersionBitRejected(params, (Consensus::DeploymentPos)i)))) {
              nVersion |= VersionBitsMask(params, (Consensus::DeploymentPos)i);
          }
      }
  
      if(IsWitnessEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nSegWitVersionMask;
  
      if(IsNtpSyncEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nNSyncVersionMask;
  
      if(IsCommunityFundEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nCFundVersionMask;
  
      if(IsCommunityFundAccumulationEnabled(pindexPrev,Params().GetConsensus(), true))
          nVersion |= nCFundAccVersionMask;
  
      if(IsColdStakingEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nColdStakingVersionMask;
  
      if(IsCommunityFundAccumulationSpreadEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nCFundAccSpreadVersionMask;
  
      if(IsCommunityFundAmountV2Enabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nCFundAmountV2Mask;
  
      if(IsStaticRewardEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nStaticRewardVersionMask;
  
      if(IsReducedCFundQuorumEnabled(pindexPrev,Params().GetConsensus()))
          nVersion |= nCFundReducedQuorumMask;
  
      if(pindexPrev->nHeight >= Params().GetConsensus().nHeightv451Fork)
          nVersion |= nV451ForkMask;
  
      if(pindexPrev->nHeight >= Params().GetConsensus().nHeightv452Fork)
          nVersion |= nV452ForkMask;
  
      return nVersion;
  }
  
  static bool IsSigHFEnabled(const Consensus::Params &consensus, int64_t nMedianTimePast) {
      return nMedianTimePast >=
             consensus.sigActivationTime;
  }
  
  bool IsSigHFEnabled(const Consensus::Params &consensus, const CBlockIndex *pindexPrev) {
      if (pindexPrev == nullptr) {
          return false;
      }
  
      return IsSigHFEnabled(consensus, pindexPrev->GetMedianTimePast());
  }
  
  /**
   * Threshold condition checker that triggers when unknown versionbits are seen on the network.
   */
  class WarningBitsConditionChecker : public AbstractThresholdConditionChecker
  {
  private:
      int bit;
  
  public:
      WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}
  
      int64_t BeginTime(const Consensus::Params& params) const { return 0; }
      int64_t EndTime(const Consensus::Params& params) const { return std::numeric_limits<int64_t>::max(); }
      int Period(const Consensus::Params& params) const { return params.nMinerConfirmationWindow; }
      int Threshold(const Consensus::Params& params) const { return params.nRuleChangeActivationThreshold; }
  
      bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const
      {
          return  (pindex->nVersion & VERSIONBITS_TOP_MASK) == (IsSigHFEnabled(Params().GetConsensus(), pindex) ? VERSIONBITS_TOP_BITS_SIG : VERSIONBITS_TOP_BITS) &&
                 ((pindex->nVersion >> bit) & 1) != 0 &&
                 ((ComputeBlockVersion(pindex->pprev, params) >> bit) & 1) == 0;
      }
  };
  
  bool TxToProposal(std::string strDZeel, uint256 hash, const uint256& blockhash, const CAmount& nProposalFee, CFund::CProposal& proposal)
  {
      UniValue metadata(UniValue::VOBJ);
      try {
          UniValue valRequest;
          if (!valRequest.read(strDZeel))
              return error("%s: Could not read strDZeel of Proposal\n", __func__);
  
          if (valRequest.isObject())
              metadata = valRequest.get_obj();
          else
              return error("%s: Could not read strDZeel of Proposal\n", __func__);
  
      } catch (const UniValue& objError) {
          error("%s: Could not read strDZeel of Proposal\n", __func__);
      } catch (const std::exception& e) {
          return error("%s: Could not read strDZeel of Proposal: %s\n", __func__, e.what());
      }
  
      proposal.nAmount = find_value(metadata, "n").get_int64();
      proposal.Address = find_value(metadata, "a").get_str();
      proposal.nDeadline = find_value(metadata, "d").get_int64();
      proposal.strDZeel = find_value(metadata, "s").get_str();
      proposal.nVersion = find_value(metadata, "v").isNum() ? find_value(metadata, "v").get_int() : 1;
      proposal.nFee = nProposalFee;
      proposal.hash = hash;
      proposal.txblockhash = blockhash;
      proposal.fDirty = true;
  
      if(proposal.nAmount < 0) {
          return error("%s: Proposal cannot have an amount less than 0\n", __func__);
      }
  
      return true;
  }
  
  bool TxToPaymentRequest(std::string strDZeel, uint256 hash, const uint256& blockhash,  CFund::CPaymentRequest& prequest, CCoinsViewCache& view)
  {
      UniValue metadata(UniValue::VOBJ);
      try {
          UniValue valRequest;
          if (!valRequest.read(strDZeel))
              return error("%s: Could not read strDZeel of Payment Request\n", __func__);
  
          if (valRequest.isObject())
              metadata = valRequest.get_obj();
          else
              return error("%s: Could not read strDZeel of Payment Request\n", __func__);
  
      } catch (const UniValue& objError) {
          return error("%s: Could not read strDZeel of Payment Request\n", __func__);
      } catch (const std::exception& e) {
          return error("%s: Could not read strDZeel of Payment Request: %s\n", __func__, e.what());
      }  // May not return ever false, as transactions were already checked.
  
      prequest.hash = hash;
      prequest.nAmount = find_value(metadata, "n").get_int64();
      prequest.proposalhash = uint256S("0x" + find_value(metadata, "h").get_str());
      prequest.strDZeel = find_value(metadata, "i").get_str();
      prequest.nVersion = find_value(metadata, "v").isNum() ? find_value(metadata, "v").get_int() : 1;
      prequest.txblockhash = blockhash;
      prequest.fDirty = true;
  
      if(prequest.nAmount < 0) {
          return error("%s: Payment request cannot have an amount less than 0\n", __func__);
      }
  
      return true;
  }
  
  // Protected by cs_main
  static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS];
  
  static int64_t nTimeCheck = 0;
  static int64_t nTimeForks = 0;
  static int64_t nTimeVerify = 0;
  static int64_t nTimeConnect = 0;
  static int64_t nTimeIndex = 0;
  static int64_t nTimeCallbacks = 0;
  static int64_t nTimeTotal = 0;
  
  bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex,
                    CCoinsViewCache& view, const CChainParams& chainparams, bool fJustCheck, bool fProofOfStake)
  {
  
      AssertLockHeld(cs_main);
  
      pindex->nCFSupply = pindex->pprev != NULL ? pindex->pprev->nCFSupply : 0;
      pindex->nCFLocked = pindex->pprev != NULL ? pindex->pprev->nCFLocked : 0;
  
      pindex->vProposalVotes.clear();
      pindex->vPaymentRequestVotes.clear();
  
      if (block.IsProofOfStake())
      {
          pindex->SetProofOfStake();
          pindex->prevoutStake = block.vtx[1].vin[0].prevout;
          pindex->nStakeTime = block.vtx[1].nTime;
      }
      else
      {
          pindex->prevoutStake.SetNull();
          pindex->nStakeTime = 0;
      }
  
      int64_t nTimeStart = GetTimeMicros();
      int64_t nStakeReward = 0;
  
      // Check it again in case a previous version let a bad block in
      if (!CheckBlock(block, state, chainparams.GetConsensus(), !fJustCheck, !fJustCheck, !fJustCheck))
          return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));
  
      // verify that the view's current state corresponds to the previous block
      uint256 hashPrevBlock = pindex->pprev == NULL ? uint256() : pindex->pprev->GetBlockHash();
  
      assert(hashPrevBlock == view.GetBestBlock());
  
      // Special case for the genesis block, skipping connection of its transactions
      // (its coinbase is unspendable)
  
      if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
          if (!fJustCheck)
              view.SetBestBlock(pindex->GetBlockHash());
          return true;
      }
  
      if (pindex->IsProofOfStake())
          setStakeSeen.insert(make_pair(pindex->prevoutStake, pindex->nStakeTime));
  
  
      // Check proof of stake
      if (block.nBits != GetNextTargetRequired(pindex->pprev, block.IsProofOfStake())){
          return state.DoS(1,error("ContextualCheckBlock() : incorrect %s at height %d (%d)", !block.IsProofOfStake() ? "proof-of-work" : "proof-of-stake",pindex->pprev->nHeight, block.nBits), REJECT_INVALID, "bad-diffbits");
      }
  
      arith_uint256 hashProof;
  
      // Verify hash target and signature of coinstake tx
      if (block.IsProofOfStake())
      {
          arith_uint256 targetProofOfStake;
          // Signature will be checked in CheckInputs(), we can avoid it here (fCheckSignature = false)
          if (!CheckProofOfStake(pindex->pprev, block.vtx[1], block.nBits, hashProof, targetProofOfStake, NULL, false))
          {
                return error("ConnectBlock() : check proof-of-stake signature failed for block %s", block.GetHash().GetHex());
          }
      }
  
      if (block.IsProofOfWork())
          hashProof = UintToArith256(block.GetPoWHash());
  
      if (!pindex->SetStakeEntropyBit(block.GetStakeEntropyBit()))
          return state.DoS(1,error("ConnectBlock() : SetStakeEntropyBit() failed"), REJECT_INVALID, "bad-entropy-bit");
  
      // Record proof hash value
      pindex->hashProof = hashProof;
  
      uint64_t nStakeModifier = 0;
      bool fGeneratedStakeModifier = false;
      if (!ComputeNextStakeModifier(pindex->pprev, nStakeModifier, fGeneratedStakeModifier))
          return state.DoS(1, error("ConnectBlock() : ComputeNextStakeModifier() failed"), REJECT_INVALID, "bad-stake-modifier");
  
      pindex->SetStakeModifier(nStakeModifier, fGeneratedStakeModifier);
  
      // Flag the block index so we can be sure it will be saved on disk
      if (!pindex->IsValid(BLOCK_VALID_STAKE))
      {
          pindex->RaiseValidity(BLOCK_VALID_STAKE);
          setDirtyBlockIndex.insert(pindex);
      }
  
  
      bool fScriptChecks = true;
      if (fCheckpointsEnabled) {
          CBlockIndex *pindexLastCheckpoint = Checkpoints::GetLastCheckpoint(chainparams.Checkpoints());
          if (pindexLastCheckpoint && pindexLastCheckpoint->GetAncestor(pindex->nHeight) == pindex) {
              // This block is an ancestor of a checkpoint: disable script checks
              fScriptChecks = false;
          }
      }
  
      int64_t nTime1 = GetTimeMicros(); nTimeCheck += nTime1 - nTimeStart;
      LogPrint("bench", "    - Sanity checks: %.2fms [%.2fs]\n", 0.001 * (nTime1 - nTimeStart), nTimeCheck * 0.000001);
  
      // Do not allow blocks that contain transactions which 'overwrite' older transactions,
      // unless those are already completely spent.
      // If such overwrites are allowed, coinbases and transactions depending upon those
      // can be duplicated to remove the ability to spend the first instance -- even after
      // being sent to another address.
      // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
      // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
      // already refuses previously-known transaction ids entirely.
      // This rule was originally applied to all blocks with a timestamp after March 15, 2012, 0:00 UTC.
      // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the
      // two in the chain that violate it. This prevents exploiting the issue against nodes during their
      // initial block download.
      bool fEnforceBIP30 = (!pindex->phashBlock); // || Enforce on CreateNewBlock invocations which don't have a hash.
                            // !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
                            //  (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256S("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")));
  
      // Once BIP34 activated it was not possible to create new duplicate coinbases and thus other than starting
      // with the 2 existing duplicate coinbase pairs, not possible to create overwriting txs.  But by the
      // time BIP34 activated, in each of the existing pairs the duplicate coinbase had overwritten the first
      // before the first had been spent.  Since those coinbases are sufficiently buried its no longer possible to create further
      // duplicate transactions descending from the known pairs either.
      // If we're on the known chain at height greater than where BIP34 activated, we can save the db accesses needed for the BIP30 check.
      CBlockIndex *pindexBIP34height = pindex->pprev->GetAncestor(chainparams.GetConsensus().BIP34Height);
      //Only continue to enforce if we're below BIP34 activation height or the block hash at that height doesn't correspond.
      fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height || !(pindexBIP34height->GetBlockHash() == chainparams.GetConsensus().BIP34Hash));
  
      if (fEnforceBIP30) {
          BOOST_FOREACH(const CTransaction& tx, block.vtx) {
              const CCoins* coins = view.AccessCoins(tx.GetHash());
              if (coins && !coins->IsPruned())
                  return state.DoS(100, error("ConnectBlock(): tried to overwrite transaction"),
                                   REJECT_INVALID, "bad-txns-BIP30");
          }
      }
  
      // BIP16 didn't become active until Apr 1 2012
      int64_t nBIP16SwitchTime = 1333238400;
      bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
  
      unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
  
      // Start enforcing the DERSIG (BIP66) rules, for block.nVersion=3 blocks,
      // when 75% of the network has upgraded:
      if (block.nVersion >= 3 && IsSuperMajority(3, pindex->pprev, chainparams.GetConsensus().nMajorityEnforceBlockUpgrade, chainparams.GetConsensus())) {
          flags |= SCRIPT_VERIFY_DERSIG;
      }
  
      // Start enforcing CHECKLOCKTIMEVERIFY, (BIP65) for block.nVersion=4
      // blocks, when 75% of the network has upgraded:
      if (block.nVersion >= 4 && IsSuperMajority(4, pindex->pprev, chainparams.GetConsensus().nMajorityEnforceBlockUpgrade, chainparams.GetConsensus())) {
          flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
      }
  
      // Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY) using versionbits logic.
      int nLockTimeFlags = 0;
      if (VersionBitsState(pindex->pprev, chainparams.GetConsensus(), Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
          flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
          nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
      }
  
      // Start enforcing WITNESS rules using versionbits logic.
      if (IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) {
          flags |= SCRIPT_VERIFY_WITNESS;
      }
  
      int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1;
      LogPrint("bench", "    - Fork checks: %.2fms [%.2fs]\n", 0.001 * (nTime2 - nTime1), nTimeForks * 0.000001);
  
      CBlockUndo blockundo;
  
      std::vector<uint256> vOrphanErase;
      std::vector<int> prevheights;
      CAmount nFees = 0;
      int nInputs = 0;
      int64_t nSigOpsCost = 0;
      CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
      std::vector<std::pair<uint256, CDiskTxPos> > vPos;
      vPos.reserve(block.vtx.size());
      blockundo.vtxundo.reserve(block.vtx.size() - 1);
      std::vector<std::pair<CAddressIndexKey, CAmount> > addressIndex;
      std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > addressUnspentIndex;
      std::vector<std::pair<CSpentIndexKey, CSpentIndexValue> > spentIndex;
  
      CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);
      std::vector<PrecomputedTransactionData> txdata;
      txdata.reserve(block.vtx.size()); // Required so that pointers to individual PrecomputedTransactionData don't get invalidated
  
      for (unsigned int i = 0; i < block.vtx.size(); i++)
      {
          const CTransaction &tx = block.vtx[i];
          const uint256 txhash = tx.GetHash();
  
          nInputs += tx.vin.size();
  
          if (IsCommunityFundEnabled(pindex->pprev, chainparams.GetConsensus()))
          {
              // Add Community Fund Votes from the block coinbase
              if(tx.IsCoinBase())
              {
                  for (size_t j = 0; j < tx.vout.size(); j++)
                  {
                      std::map<uint256, bool> votes;
                      uint256 hash;
                      bool vote;
  
                      if(tx.vout[j].IsVote())
                          tx.vout[j].scriptPubKey.ExtractVote(hash, vote);
  
                      if(tx.vout[j].IsProposalVote())
                      {
                          if(votes.count(hash) == 0)
                          {
                              votes[hash] = vote;
                              CProposal proposal;
                              if(view.GetProposal(hash, proposal))
                              {
                                  if(proposal.CanVote())
                                  {
                                      pindex->vProposalVotes.push_back(make_pair(hash, vote));
                                  }
                              }
                          }
                      }
                      else if (tx.vout[j].IsPaymentRequestVote())
                      {
                          if(votes.count(hash) == 0)
                          {
                              votes[hash] = vote;
                              CPaymentRequest prequest;
  
                              if (view.GetPaymentRequest(hash, prequest))
                              {
                                  CProposal proposal;
  
                                  if (view.GetProposal(prequest.proposalhash, proposal))
                                  {
                                      if (mapBlockIndex.count(proposal.blockhash) == 0)
                                          continue;
  
                                      CBlockIndex* pblockindex = mapBlockIndex[proposal.blockhash];
  
                                      if(pblockindex == NULL)
                                          continue;
  
                                      if((proposal.CanRequestPayments() || proposal.fState == CFund::PENDING_VOTING_PREQ)
                                              && prequest.CanVote(view)
                                              && pindex->nHeight - pblockindex->nHeight > Params().GetConsensus().nCommunityFundMinAge)
                                      {
                                          pindex->vPaymentRequestVotes.push_back(make_pair(hash, vote));
                                      }
  
                                  }
                              }
                          }
                      }
                  }
              }
  
              bool fReducedQuorum = IsReducedCFundQuorumEnabled(chainActive.Tip(), Params().GetConsensus());
              int nMaxVersionProposal = fReducedQuorum ? Params().GetConsensus().nProposalMaxVersion : 2;
              int nMaxVersionPaymentRequest = fReducedQuorum ? Params().GetConsensus().nPaymentRequestMaxVersion : 2;
  
              if(tx.nVersion == CTransaction::PROPOSAL_VERSION) // Community Fund Proposal
                  if(!CFund::IsValidProposal(tx, nMaxVersionProposal))
                      return state.DoS(10, false, REJECT_INVALID, "bad-cfund-proposal");
  
              if(tx.nVersion == CTransaction::PAYMENT_REQUEST_VERSION) // Community Fund Payment Request
                  if(!CFund::IsValidPaymentRequest(tx, view, nMaxVersionPaymentRequest))
                      return state.DoS(10, false, REJECT_INVALID, "bad-cfund-payment-request");
          }
  
          if (!tx.IsCoinBase())
          {
              if (!view.HaveInputs(tx))
                  return state.DoS(100, error("ConnectBlock(): inputs missing/spent"),
                                   REJECT_INVALID, "bad-txns-inputs-missingorspent");
  
              // Check that transaction is BIP68 final
              // BIP68 lock checks (as opposed to nLockTime checks) must
              // be in ConnectBlock because they require the UTXO set
              prevheights.resize(tx.vin.size());
              for (size_t j = 0; j < tx.vin.size(); j++) {
                  prevheights[j] = view.AccessCoins(tx.vin[j].prevout.hash)->nHeight;
              }
  
              // Which orphan pool entries must we evict?
              for (size_t j = 0; j < tx.vin.size(); j++) {
                  auto itByPrev = mapOrphanTransactionsByPrev.find(tx.vin[j].prevout);
                  if (itByPrev == mapOrphanTransactionsByPrev.end()) continue;
                  for (auto mi = itByPrev->second.begin(); mi != itByPrev->second.end(); ++mi) {
                      const CTransaction& orphanTx = (*mi)->second.tx;
                      const uint256& orphanHash = orphanTx.GetHash();
                      vOrphanErase.push_back(orphanHash);
                  }
              }
  
              if (!SequenceLocks(tx, nLockTimeFlags, &prevheights, *pindex)) {
                  return state.DoS(100, error("%s: contains a non-BIP68-final transaction", __func__),
                                   REJECT_INVALID, "bad-txns-nonfinal");
              }
  
              if (fAddressIndex || fSpentIndex)
              {
                  for (size_t j = 0; j < tx.vin.size(); j++) {
  
                      const CTxIn input = tx.vin[j];
                      const CTxOut &prevout = view.GetOutputFor(tx.vin[j]);
                      uint160 hashBytes;
                      int addressType;
  
                      if (prevout.scriptPubKey.IsPayToScriptHash()) {
                          hashBytes = uint160(vector <unsigned char>(prevout.scriptPubKey.begin()+2, prevout.scriptPubKey.begin()+22));
                          addressType = 2;
                      } else if (prevout.scriptPubKey.IsPayToPublicKeyHash()) {
                          hashBytes = uint160(vector <unsigned char>(prevout.scriptPubKey.begin()+3, prevout.scriptPubKey.begin()+23));
                          addressType = 1;
                      } else if (prevout.scriptPubKey.IsPayToPublicKey() || prevout.scriptPubKey.IsColdStaking()) {
                          CTxDestination destination;
                          ExtractDestination(prevout.scriptPubKey, destination);
                          CNavCoinAddress address(destination);
                          if (prevout.scriptPubKey.IsColdStaking())
                              address.GetSpendingAddress(address);
                          address.GetIndexKey(hashBytes, addressType);
                      } else {
                          hashBytes.SetNull();
                          addressType = 0;
                      }
  
                      if (fAddressIndex && addressType > 0) {
                          // record spending activity
                          addressIndex.push_back(make_pair(CAddressIndexKey(addressType, hashBytes, pindex->nHeight, i, txhash, j, true), prevout.nValue * -1));
  
                          // remove address from unspent index
                          addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(addressType, hashBytes, input.prevout.hash, input.prevout.n), CAddressUnspentValue()));
                      }
  
                      if (fSpentIndex) {
                          // add the spent index to determine the txid and input that spent an output
                          // and to find the amount and address from an input
                          spentIndex.push_back(make_pair(CSpentIndexKey(input.prevout.hash, input.prevout.n), CSpentIndexValue(txhash, j, pindex->nHeight, prevout.nValue, addressType, hashBytes)));
                      }
                  }
  
              }
          }
  
          // GetTransactionSigOpCost counts 3 types of sigops:
          // * legacy (always)
          // * p2sh (when P2SH enabled in flags and excludes coinbase)
          // * witness (when witness enabled in flags and excludes coinbase)
          nSigOpsCost += GetTransactionSigOpCost(tx, view, flags);
          if (nSigOpsCost > MAX_BLOCK_SIGOPS_COST)
              return state.DoS(100, error("ConnectBlock(): too many sigops"),
                               REJECT_INVALID, "bad-blk-sigops");
  
          txdata.emplace_back(tx);
  
          if (!tx.IsCoinBase())
          {
  
              if (!tx.IsCoinStake())
                  nFees += view.GetValueIn(tx) - tx.GetValueOut();
              if (tx.IsCoinStake())
              {
  
                  nStakeReward = tx.GetValueOut() - view.GetValueIn(tx);
                  pindex->strDZeel = tx.strDZeel;
  
                  if(IsCommunityFundAccumulationEnabled(pindex->pprev, Params().GetConsensus(), false))
                  {
                      int nMultiplier = 1;
  
                      if(IsCommunityFundAccumulationSpreadEnabled(pindex->pprev, Params().GetConsensus()))
                          nMultiplier = (pindex->nHeight % Params().GetConsensus().nBlockSpreadCFundAccumulation) == 0 ? Params().GetConsensus().nBlockSpreadCFundAccumulation : 0;
  
                      if(!tx.vout[tx.vout.size() - 1].IsCommunityFundContribution() && nMultiplier > 0)
                          return state.DoS(100, error("ConnectBlock(): block does not contribute to the community fund"),
                                           REJECT_INVALID, "no-cf-amount");
  
  
                      if(IsCommunityFundAmountV2Enabled(pindex->pprev, Params().GetConsensus())) {
                          if(tx.vout[tx.vout.size() - 1].nValue != Params().GetConsensus().nCommunityFundAmountV2 * nMultiplier && nMultiplier > 0)
                              return state.DoS(100, error("ConnectBlock(): block pays incorrect amount to community fund (actual=%d vs consensus=%d)",
                                                          tx.vout[tx.vout.size() - 1].nValue, Params().GetConsensus().nCommunityFundAmountV2 * nMultiplier),
                                      REJECT_INVALID, "bad-cf-amount");
                      } else {
                          if(tx.vout[tx.vout.size() - 1].nValue != Params().GetConsensus().nCommunityFundAmount * nMultiplier && nMultiplier > 0)
                              return state.DoS(100, error("ConnectBlock(): block pays incorrect amount to community fund (actual=%d vs consensus=%d)",
                                                          tx.vout[tx.vout.size() - 1].nValue, Params().GetConsensus().nCommunityFundAmount * nMultiplier),
                                      REJECT_INVALID, "bad-cf-amount");
                      }
  
  
                      if(IsCommunityFundAmountV2Enabled(pindex->pprev, Params().GetConsensus()))
                      {
                          nStakeReward -= Params().GetConsensus().nCommunityFundAmountV2 * nMultiplier;
                      } else {
                          nStakeReward -= Params().GetConsensus().nCommunityFundAmount * nMultiplier;
                      }
                  }
              }
  
              std::vector<CScriptCheck> vChecks;
              bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
              if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : NULL))
                  return error("ConnectBlock(): CheckInputs on %s failed with %s",
                      tx.GetHash().ToString(), FormatStateMessage(state));
              control.Add(vChecks);
  
          } else {
              if (tx.nTime < block.nTime && pindex->nHeight > Params().GetConsensus().nCoinbaseTimeActivationHeight)
                  return error("ConnectBlock(): Coinbase timestamp doesn't meet protocol (tx=%d vs block=%d)",
                               tx.nTime, block.nTime);
          }
  
          if (fAddressIndex) {
              for (unsigned int k = 0; k < tx.vout.size(); k++) {
                  const CTxOut &out = tx.vout[k];
  
                  if (out.scriptPubKey.IsPayToScriptHash()) {
                      vector<unsigned char> hashBytes(out.scriptPubKey.begin()+2, out.scriptPubKey.begin()+22);
  
                      // record receiving activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(2, uint160(hashBytes), pindex->nHeight, i, txhash, k, false), out.nValue));
  
                      // record unspent output
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(2, uint160(hashBytes), txhash, k), CAddressUnspentValue(out.nValue, out.scriptPubKey, pindex->nHeight)));
  
                  } else if (out.scriptPubKey.IsPayToPublicKey() || out.scriptPubKey.IsColdStaking()) {
                      uint160 hashBytes;
                      int type = 0;
                      CTxDestination destination;
                      ExtractDestination(out.scriptPubKey, destination);
                      CNavCoinAddress address(destination);
                      if (out.scriptPubKey.IsColdStaking())
                          address.GetSpendingAddress(address);
                      address.GetIndexKey(hashBytes, type);
  
                      // undo spending activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(type, uint160(hashBytes), pindex->nHeight, i, txhash, k, true), out.nValue));
  
                      // restore unspent index
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(type, uint160(hashBytes), txhash, k), CAddressUnspentValue(out.nValue, out.scriptPubKey, pindex->nHeight)));
  
                  } else if (out.scriptPubKey.IsPayToPublicKeyHash()) {
                      vector<unsigned char> hashBytes(out.scriptPubKey.begin()+3, out.scriptPubKey.begin()+23);
  
                      // record receiving activity
                      addressIndex.push_back(make_pair(CAddressIndexKey(1, uint160(hashBytes), pindex->nHeight, i, txhash, k, false), out.nValue));
  
                      // record unspent output
                      addressUnspentIndex.push_back(make_pair(CAddressUnspentKey(1, uint160(hashBytes), txhash, k), CAddressUnspentValue(out.nValue, out.scriptPubKey, pindex->nHeight)));
  
                  } else {
                      continue;
                  }
  
              }
          }
  
          bool fContribution = false;
          CAmount nProposalFee = 0;
  
          BOOST_FOREACH(const CTxOut& vout, tx.vout)
          {
            if(vout.IsCommunityFundContribution())
            {
              fContribution=true;
              pindex->nCFSupply += vout.nValue;
              nProposalFee += vout.nValue;
            }
          }
  
          if(IsCommunityFundEnabled(pindex->pprev, Params().GetConsensus())) {
              bool fReducedQuorum = IsReducedCFundQuorumEnabled(chainActive.Tip(), Params().GetConsensus());
              int nMaxVersionProposal = fReducedQuorum ? Params().GetConsensus().nProposalMaxVersion : 2;
              int nMaxVersionPaymentRequest = fReducedQuorum ? Params().GetConsensus().nPaymentRequestMaxVersion : 2;
  
              if(fContribution && tx.nVersion == CTransaction::PROPOSAL_VERSION && CFund::IsValidProposal(tx, nMaxVersionProposal)){
                  CFund::CProposal proposal;
                  if (TxToProposal(tx.strDZeel, tx.GetHash(), block.GetHash(), nProposalFee, proposal))
                  {
                      view.AddProposal(proposal);
                      LogPrint("cfund","New proposal %s\n", proposal.ToString(view, block.nTime));
                  }
                  else
                  {
                      return false;
                  }
              }
  
              if(tx.nVersion == CTransaction::PAYMENT_REQUEST_VERSION && CFund::IsValidPaymentRequest(tx, view, nMaxVersionPaymentRequest)){
                  CFund::CPaymentRequest prequest;
                  if (TxToPaymentRequest(tx.strDZeel, tx.GetHash(), block.GetHash(), prequest, view))
                  {
                      view.AddPaymentRequest(prequest);
                      LogPrint("cfund","New payment request %s\n", prequest.ToString());
                  }
                  else
                  {
                      return false;
                  }
              }
          }
  
  
          CTxUndo undoDummy;
          if (i > 0) {
              blockundo.vtxundo.push_back(CTxUndo());
          }
          UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);
  
          vPos.push_back(std::make_pair(tx.GetHash(), pos));
          pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
      }
  
      int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2;
      LogPrint("bench", "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs]\n", (unsigned)block.vtx.size(), 0.001 * (nTime3 - nTime2), 0.001 * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : 0.001 * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * 0.000001);
  
      CAmount nPOWBlockReward = block.IsProofOfWork() ? nFees + GetBlockSubsidy(pindex->nHeight, chainparams.GetConsensus()) : 0;
  
      // Coinbase output can only include outputs with value if:
      //  - its a POW block, POW blocks are allowed and the value meets the consensus rules, or
      //  - if it contains an accepted payment request which is correctly referred on the strDZeel.
  
      int nPaymentRequestsCount = 0;
      CAmount nAccValue = 0;
      for (unsigned int i = 0; i < block.vtx[0].vout.size(); i++) {
          bool isJson = true;
          UniValue metadata(UniValue::VARR);
          try {
              UniValue valRequest;
              if (!valRequest.read(block.vtx[0].strDZeel))
                  isJson = false;
  
              if (valRequest.isArray())
                  metadata = valRequest.get_array();
              else
                  isJson = false;
  
          } catch (const UniValue& objError) {
              isJson = false;
          } catch (const std::exception& e) {
              isJson = false;
          }
  
          nAccValue += block.vtx[0].vout[i].nValue;
  
          if(nAccValue > nPOWBlockReward && block.vtx[0].vout[i].nValue > 0) {
              if(!isJson)
                  return state.DoS(100, error("CheckBlock() : coinbase pays too much (%d vs %d).", block.vtx[0].GetValueOut(), nPOWBlockReward));
              if(metadata[nPaymentRequestsCount].isStr())
              {
                  uint256 prid = uint256S(metadata[nPaymentRequestsCount].get_str());
  
                  if(!view.HavePaymentRequest(prid))
                      return state.DoS(100, error("CheckBlock() : coinbase strdzeel refers wrong payment request hash."));
  
                  CPaymentRequestModifier prequest = view.ModifyPaymentRequest(prid);
                  CFund::CProposal proposal;
  
                  if(!view.GetProposal(prequest->proposalhash, proposal))
                      return state.DoS(100, error("CheckBlock() : coinbase strdzeel payment request does not have parent proposal."));
  
                  CTxDestination address;
                  bool fValidAddress = ExtractDestination(block.vtx[0].vout[i].scriptPubKey, address);
  
                  if(!fValidAddress)
                      return state.DoS(100, error("CheckBlock() : coinbase cant extract destination from scriptpubkey."));
  
                  if (mapBlockIndex.count(prequest->blockhash) == 0)
                      return state.DoS(100, error("CheckBlock() : cant find payment request block %s", prequest->blockhash.ToString()));
  
                  CBlockIndex* pblockindex = mapBlockIndex[prequest->blockhash];
  
                  if(pblockindex == NULL)
                      return state.DoS(100, error("CheckBlock() : cant find payment request block %s.", prequest->blockhash.ToString()));
  
                  if(!(pindex->pprev->nHeight - pblockindex->nHeight > Params().GetConsensus().nCommunityFundMinAge))
                      return state.DoS(100, error("CheckBlock() : payment request not mature enough."));
  
                  if(block.vtx[0].vout[i].nValue != prequest->nAmount || prequest->fState != CFund::ACCEPTED || proposal.Address != CNavCoinAddress(address).ToString())
                      return state.DoS(100, error("CheckBlock() : coinbase output does not match an accepted payment request"));
  
                  if(prequest->paymenthash != uint256() && pindex->pprev->nHeight >= Params().GetConsensus().nHeightv452Fork)
                      return state.DoS(100, error("CheckBlock() : coinbase output tries to pay an already paid payment request"));
  
                  prequest->paymenthash = block.GetHash();
              }
              else
              {
                  return state.DoS(100, error("CheckBlock() : coinbase strdzeel %s array does not include a string (%d) at position %d",
                                              block.vtx[0].strDZeel, metadata[nPaymentRequestsCount].type(), nPaymentRequestsCount));
              }
              nPaymentRequestsCount++;
          }
      }
  
      if (block.IsProofOfStake())
      {
          // ppcoin: coin stake tx earns reward instead of paying fee
          uint64_t nCoinAge;
          if (!TransactionGetCoinAge(const_cast<CTransaction&>(block.vtx[1]), nCoinAge))
              return error("ConnectBlock() : %s unable to get coin age for coinstake", block.vtx[1].GetHash().ToString());
  
          int64_t nCalculatedStakeReward = GetProofOfStakeReward(pindex->nHeight, nCoinAge, nFees, pindex->pprev);
  
          if (nStakeReward > nCalculatedStakeReward)
              return state.DoS(100, error("ConnectBlock() : coinstake pays too much(actual=%d vs calculated=%d)", nStakeReward, nCalculatedStakeReward));
      }
  
      if (!control.Wait()) {
          return state.DoS(100, false);
      }
      int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2;
      LogPrint("bench", "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs]\n", nInputs - 1, 0.001 * (nTime4 - nTime2), nInputs <= 1 ? 0 : 0.001 * (nTime4 - nTime2) / (nInputs-1), nTimeVerify * 0.000001);
  
      if (fJustCheck)
          return true;
  
      // Write undo information to disk
      if (pindex->GetUndoPos().IsNull() || !pindex->IsValid(BLOCK_VALID_SCRIPTS))
      {
          if (pindex->GetUndoPos().IsNull()) {
              CDiskBlockPos pos;
              if (!FindUndoPos(state, pindex->nFile, pos, ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) + 40))
                  return error("ConnectBlock(): FindUndoPos failed");
              if (!UndoWriteToDisk(blockundo, pos, pindex->pprev->GetBlockHash(), chainparams.MessageStart()))
                  return AbortNode(state, "Failed to write undo data");
  
              // update nUndoPos in block index
              pindex->nUndoPos = pos.nPos;
              pindex->nStatus |= BLOCK_HAVE_UNDO;
          }
  
          pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
          setDirtyBlockIndex.insert(pindex);
      }
  
      if (fTxIndex)
          if (!pblocktree->WriteTxIndex(vPos))
              return AbortNode(state, "Failed to write transaction index");
  
      if (fAddressIndex) {
          if (!pblocktree->WriteAddressIndex(addressIndex)) {
              return AbortNode(state, "Failed to write address index");
          }
  
          if (!pblocktree->UpdateAddressUnspentIndex(addressUnspentIndex)) {
              return AbortNode(state, "Failed to write address unspent index");
          }
      }
  
      if (fSpentIndex)
          if (!pblocktree->UpdateSpentIndex(spentIndex))
              return AbortNode(state, "Failed to write transaction index");
  
      if (fTimestampIndex) {
          unsigned int logicalTS = pindex->nTime;
          unsigned int prevLogicalTS = 0;
  
          // retrieve logical timestamp of the previous block
          if (pindex->pprev)
              if (!pblocktree->ReadTimestampBlockIndex(pindex->pprev->GetBlockHash(), prevLogicalTS))
                  LogPrintf("%s: Failed to read previous block's logical timestamp\n", __func__);
  
          if (logicalTS <= prevLogicalTS) {
              logicalTS = prevLogicalTS + 1;
              LogPrintf("%s: Previous logical timestamp is newer Actual[%d] prevLogical[%d] Logical[%d]\n", __func__, pindex->nTime, prevLogicalTS, logicalTS);
          }
  
          if (!pblocktree->WriteTimestampIndex(CTimestampIndexKey(logicalTS, pindex->GetBlockHash())))
              return AbortNode(state, "Failed to write timestamp index");
  
          if (!pblocktree->WriteTimestampBlockIndex(CTimestampBlockIndexKey(pindex->GetBlockHash()), CTimestampBlockIndexValue(logicalTS)))
              return AbortNode(state, "Failed to write blockhash index");
      }
  
      // add this block to the view's block chain
      view.SetBestBlock(pindex->GetBlockHash());
  
      int64_t nTime5 = GetTimeMicros(); nTimeIndex += nTime5 - nTime4;
      LogPrint("bench", "    - Index writing: %.2fms [%.2fs]\n", 0.001 * (nTime5 - nTime4), nTimeIndex * 0.000001);
  
      // Watch for changes to the previous coinbase transaction.
      static uint256 hashPrevBestCoinBase;
      GetMainSignals().UpdatedTransaction(hashPrevBestCoinBase);
      hashPrevBestCoinBase = block.vtx[0].GetHash();
  
      // Erase orphan transactions include or precluded by this block
      if (vOrphanErase.size()) {
          int nErased = 0;
          BOOST_FOREACH(uint256 &orphanHash, vOrphanErase) {
              nErased += EraseOrphanTx(orphanHash);
          }
          LogPrint("mempool", "Erased %d orphan tx included or conflicted by block\n", nErased);
      }
  
      int64_t nTime6 = GetTimeMicros(); nTimeCallbacks += nTime6 - nTime5;
      LogPrint("bench", "    - Callbacks: %.2fms [%.2fs]\n", 0.001 * (nTime6 - nTime5), nTimeCallbacks * 0.000001);
  
      return true;
  }
  
  
  /**
   * Update the on-disk chain state.
   * The caches and indexes are flushed depending on the mode we're called with
   * if they're too large, if it's been a while since the last write,
   * or always and in all cases if we're in prune mode and are deleting files.
   */
  bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) {
      const CChainParams& chainparams = Params();
      int64_t nMempoolUsage = mempool.DynamicMemoryUsage();
      LOCK2(cs_main, cs_LastBlockFile);
      static int64_t nLastWrite = 0;
      static int64_t nLastFlush = 0;
      static int64_t nLastSetChain = 0;
      std::set<int> setFilesToPrune;
      bool fFlushForPrune = false;
      try {
      if (fPruneMode && fCheckForPruning && !fReindex) {
          FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
          fCheckForPruning = false;
          if (!setFilesToPrune.empty()) {
              fFlushForPrune = true;
              if (!fHavePruned) {
                  pblocktree->WriteFlag("prunedblockfiles", true);
                  fHavePruned = true;
              }
          }
      }
      int64_t nNow = GetTimeMicros();
      // Avoid writing/flushing immediately after startup.
      if (nLastWrite == 0) {
          nLastWrite = nNow;
      }
      if (nLastFlush == 0) {
          nLastFlush = nNow;
      }
      if (nLastSetChain == 0) {
          nLastSetChain = nNow;
      }
  
      int64_t nMempoolSizeMax = GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
      int64_t cacheSize = pcoinsTip->DynamicMemoryUsage() * DB_PEAK_USAGE_FACTOR;
      int64_t nTotalSpace = nCoinCacheUsage + std::max<int64_t>(nMempoolSizeMax - nMempoolUsage, 0);
      // The cache is large and we're within 10% and 200 MiB or 50% and 50MiB of the limit, but we have time now (not in the middle of a block processing).
      bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize > std::min(std::max(nTotalSpace / 2, nTotalSpace - MIN_BLOCK_COINSDB_USAGE * 1024 * 1024),
          std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE * 1024 * 1024));
      // The cache is over the limit, we have to write now.
      bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > (int64_t)nCoinCacheUsage;
      // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash.
      bool fPeriodicWrite = mode == FLUSH_STATE_PERIODIC && nNow > nLastWrite + (int64_t)DATABASE_WRITE_INTERVAL * 1000000;
      // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage.
      bool fPeriodicFlush = mode == FLUSH_STATE_PERIODIC && nNow > nLastFlush + (int64_t)DATABASE_FLUSH_INTERVAL * 1000000;
      // Combine all conditions that result in a full cache flush.
      bool fDoFullFlush = (mode == FLUSH_STATE_ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune;
      // Write blocks and block index to disk.
      if (fDoFullFlush || fPeriodicWrite) {
          // Depend on nMinDiskSpace to ensure we can write block index
          if (!CheckDiskSpace(0))
              return state.Error("out of disk space");
          // First make sure all block and undo data is flushed to disk.
          FlushBlockFile();
          // Then update all block file information (which may refer to block and undo files).
          {
              std::vector<std::pair<int, const CBlockFileInfo*> > vFiles;
              vFiles.reserve(setDirtyFileInfo.size());
              for (set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end(); ) {
                  vFiles.push_back(make_pair(*it, &vinfoBlockFile[*it]));
                  setDirtyFileInfo.erase(it++);
              }
              std::vector<const CBlockIndex*> vBlocks;
              vBlocks.reserve(setDirtyBlockIndex.size());
              for (set<CBlockIndex*>::iterator it = setDirtyBlockIndex.begin(); it != setDirtyBlockIndex.end(); ) {
                  vBlocks.push_back(*it);
                  setDirtyBlockIndex.erase(it++);
              }
              if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile, vBlocks)) {
                  return AbortNode(state, "Files to write to block index database");
              }
          }
          // Finally remove any pruned files
          if (fFlushForPrune)
              UnlinkPrunedFiles(setFilesToPrune);
          nLastWrite = nNow;
      }
      // Flush best chain related state. This can only be done if the blocks / block index write was also done.
      if (fDoFullFlush) {
          // Typical CCoins structures on disk are around 128 bytes in size.
          // Pushing a new one to the database can cause it to be written
          // twice (once in the log, and once in the tables). This is already
          // an overestimation, as most will delete an existing entry or
          // overwrite one. Still, use a conservative safety factor of 2.
          if (!CheckDiskSpace(128 * 2 * 2 * pcoinsTip->GetCacheSize()))
              return state.Error("out of disk space");
          // Flush the chainstate (which may refer to block index entries).
          if (!pcoinsTip->Flush())
              return AbortNode(state, "Failed to write to coin database");
          nLastFlush = nNow;
      }
      if (fDoFullFlush || ((mode == FLUSH_STATE_ALWAYS || mode == FLUSH_STATE_PERIODIC) && nNow > nLastSetChain + (int64_t)DATABASE_WRITE_INTERVAL * 1000000)) {
          // Update best block in wallet (so we can detect restored wallets).
          GetMainSignals().SetBestChain(chainActive.GetLocator());
          nLastSetChain = nNow;
      }
      } catch (const std::runtime_error& e) {
          return AbortNode(state, std::string("System error while flushing: ") + e.what());
      }
      return true;
  }
  //boost
  
  void FlushStateToDisk() {
      CValidationState state;
      FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
  }
  
  void FlushStateToDiskIfNeeded() {
      CValidationState state;
      FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED);
  }
  
  void PruneAndFlush() {
      CValidationState state;
      fCheckForPruning = true;
      FlushStateToDisk(state, FLUSH_STATE_NONE);
  }
  
  /** Update chainActive and related internal data structures. */
  void static UpdateTip(CBlockIndex *pindexNew, const CChainParams& chainParams) {
      chainActive.SetTip(pindexNew);
  
      // New best block
      nTimeBestReceived = GetTime();
      mempool.AddTransactionsUpdated(1);
  
      cvBlockChange.notify_all();
  
      static bool fWarned = false;
      std::vector<std::string> warningMessages;
      if (!IsInitialBlockDownload())
      {
          int nUpgraded = 0;
          const CBlockIndex* pindex = chainActive.Tip();
  //
  // Commented - NavCoin uses now version control
  //
  //        for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) {
  //            WarningBitsConditionChecker checker(bit);
  //            ThresholdState state = checker.GetStateFor(pindex, chainParams.GetConsensus(), warningcache[bit], bit);
  //            if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
  //                if (state == THRESHOLD_ACTIVE) {
  //                    warningMessages.push_back(strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit));
  //                    if (!fWarned) {
  //                        AlertNotify(strMiscWarning);
  //                        fWarned = true;
  //                    }
  //                } else {
  //                    warningMessages.push_back(strprintf("unknown new rules are about to activate (versionbit %i)", bit));
  //                }
  //            }
  //        }
  
          // Check the version of the last 1000 blocks to see if we need to upgrade:
          for (int i = 0; i < 1000 && pindex != NULL; i++)
          {
              int32_t nExpectedVersion = CLIENT_VERSION;
              if (atoi(pindex->strDZeel.substr(pindex->strDZeel.find(";") + 1).c_str()) > nExpectedVersion
                      && pindex->strDZeel.find(';') != std::string::npos)
                  ++nUpgraded;
              pindex = pindex->pprev;
          }
          if (nUpgraded > 0)
              warningMessages.push_back(strprintf("%d of last 1000 blocks use a new version of the wallet", nUpgraded));
          if (nUpgraded > 1000/2.5)
          {
              // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
              strMiscWarning = _("A new version of the wallet has been released. Please update as soon as possible.");
              warningMessages.push_back("A new version of the wallet has been released. Please update as soon as possible.");
              if (!fWarned) {
                  uiInterface.ThreadSafeMessageBox(
                      strMiscWarning,
                      "", CClientUIInterface::MSG_WARNING);
                  AlertNotify(strMiscWarning);
                  fWarned = true;
              }
          }
      }
      hashBestChain = chainActive.Tip()->GetBlockHash();
  
      LogPrintf("%s: new best=%s height=%d version=0x%08x log2_work=%.8g tx=%lu date='%s' progress=%f cache=%.1fMiB(%utx)", __func__,
        chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), chainActive.Tip()->nVersion,
        log(chainActive.Tip()->nChainWork.getdouble())/log(2.0), (unsigned long)chainActive.Tip()->nChainTx,
        DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
        Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip()), pcoinsTip->DynamicMemoryUsage() * (1.0 / (1<<20)), pcoinsTip->GetCacheSize());
      if (!warningMessages.empty())
          LogPrintf(" warning='%s'", boost::algorithm::join(warningMessages, ", "));
      LogPrintf("\n");
  
  }
  
  /** Disconnect chainActive's tip. You probably want to call mempool.removeForReorg and manually re-limit mempool size after this, with cs_main held. */
  bool static DisconnectTip(CValidationState& state, const CChainParams& chainparams, bool fBare = false)
  {
      CBlockIndex *pindexDelete = chainActive.Tip();
      assert(pindexDelete);
      // Read block from disk.
      CBlock block;
      if (!ReadBlockFromDisk(block, pindexDelete, chainparams.GetConsensus()))
          return AbortNode(state, "Failed to read block");
      // Apply the block atomically to the chain state.
      int64_t nStart = GetTimeMicros();
      {
          CCoinsViewCache view(pcoinsTip);
          if (!DisconnectBlock(block, state, pindexDelete, view))
              return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString());
          CFundStep(state, pindexDelete, true, view);
          assert(view.Flush());
      }
      LogPrint("bench", "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * 0.001);
  
      // Write the chain state to disk, if necessary.
      if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
          return false;
  
      if (!fBare) {
          // Resurrect mempool transactions from the disconnected block.
          std::vector<uint256> vHashUpdate;
          BOOST_FOREACH(const CTransaction &tx, block.vtx) {
              // ignore validation errors in resurrected transactions
              list<CTransaction> removed;
              CValidationState stateDummy;
              if (!(tx.IsCoinBase() || tx.IsCoinStake()) || !AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL, true)) {
                  mempool.removeRecursive(tx, removed);
              } else if (mempool.exists(tx.GetHash())) {
                  vHashUpdate.push_back(tx.GetHash());
              }
          }
          // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have
          // no in-mempool children, which is generally not true when adding
          // previously-confirmed transactions back to the mempool.
          // UpdateTransactionsFromBlock finds descendants of any transactions in this
          // block that were added back and cleans up the mempool state.
          mempool.UpdateTransactionsFromBlock(vHashUpdate);
      }
  
      // Update chainActive and related variables.
      UpdateTip(pindexDelete->pprev, chainparams);
  
      // Let wallets know transactions went from 1-confirmed to
      // 0-confirmed or conflicted:
      BOOST_FOREACH(const CTransaction &tx, block.vtx) {
          SyncWithWallets(tx, pindexDelete->pprev, NULL, false);
      }
      return true;
  }
  
  static int64_t nTimeReadFromDisk = 0;
  static int64_t nTimeConnectTotal = 0;
  static int64_t nTimeFlush = 0;
  static int64_t nTimeChainState = 0;
  static int64_t nTimePostConnect = 0;
  
  /**
   * Connect a new block to chainActive. pblock is either NULL or a pointer to a CBlock
   * corresponding to pindexNew, to bypass loading it again from disk.
   */
  bool static ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const CBlock* pblock)
  {
      assert(pindexNew->pprev == chainActive.Tip());
      // Read block from disk.
      int64_t nTime1 = GetTimeMicros();
      CBlock block;
      if (!pblock) {
          if (!ReadBlockFromDisk(block, pindexNew, chainparams.GetConsensus()))
              return AbortNode(state, "Failed to read block");
          pblock = &block;
      }
      // Apply the block atomically to the chain state.
      int64_t nTime2 = GetTimeMicros(); nTimeReadFromDisk += nTime2 - nTime1;
      int64_t nTime3;
      int64_t nTime4;
      LogPrint("bench", "  - Load block from disk: %.2fms [%.2fs]\n", (nTime2 - nTime1) * 0.001, nTimeReadFromDisk * 0.000001);
      {
          CCoinsViewCache view(pcoinsTip);
  
          bool rv = ConnectBlock(*pblock, state, pindexNew, view, chainparams);
  
          GetMainSignals().BlockChecked(*pblock, state);
          if (!rv) {
              if (state.IsInvalid())
                  InvalidBlockFound(pindexNew, state);
              return error("ConnectTip(): ConnectBlock %s failed: ", pindexNew->GetBlockHash().ToString());
          }
          mapBlockSource.erase(pindexNew->GetBlockHash());
          nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2;
          LogPrint("bench", "  - Connect total: %.2fms [%.2fs]\n", (nTime3 - nTime2) * 0.001, nTimeConnectTotal * 0.000001);
          CFundStep(state, pindexNew, false, view);
          nTime4 = GetTimeMicros(); nTimeConnectTotal += nTime4 - nTime3;
          assert(view.Flush());
      }
      int64_t nTime5 = GetTimeMicros(); nTimeFlush += nTime5 - nTime4;
      LogPrint("bench", "  - Flush: %.2fms [%.2fs]\n", (nTime5 - nTime4) * 0.001, nTimeFlush * 0.000001);
      // Write the chain state to disk, if necessary.
      if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
          return false;
      int64_t nTime6 = GetTimeMicros(); nTimeChainState += nTime6 - nTime5;
      LogPrint("bench", "  - Writing chainstate: %.2fms [%.2fs]\n", (nTime6 - nTime5) * 0.001, nTimeChainState * 0.000001);
      // Remove conflicting transactions from the mempool.
      list<CTransaction> txConflicted;
      mempool.removeForBlock(pblock->vtx, pindexNew->nHeight, txConflicted, !IsInitialBlockDownload());
      // Update chainActive & related variables.
      UpdateTip(pindexNew, chainparams);
      // Tell wallet about transactions that went from mempool
      // to conflicted:
      BOOST_FOREACH(const CTransaction &tx, txConflicted) {
          SyncWithWallets(tx, pindexNew, NULL);
      }
      // ... and about transactions that got confirmed:
      BOOST_FOREACH(const CTransaction &tx, pblock->vtx) {
          SyncWithWallets(tx, pindexNew, pblock);
      }
  
      int64_t nTime7 = GetTimeMicros(); nTimePostConnect += nTime7 - nTime6; nTimeTotal += nTime7 - nTime1;
      LogPrint("bench", "  - Connect postprocess: %.2fms [%.2fs]\n", (nTime7 - nTime6) * 0.001, nTimePostConnect * 0.000001);
      LogPrint("bench", "- Connect block: %.2fms [%.2fs]\n", (nTime7 - nTime1) * 0.001, nTimeTotal * 0.000001);
      return true;
  }
  
  /**
   * Return the tip of the chain with the most work in it, that isn't
   * known to be invalid (it's however far from certain to be valid).
   */
  static CBlockIndex* FindMostWorkChain() {
      do {
          CBlockIndex *pindexNew = NULL;
  
          // Find the best candidate header.
          {
              std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin();
              if (it == setBlockIndexCandidates.rend())
                  return NULL;
              pindexNew = *it;
          }
  
          // Check whether all blocks on the path between the currently active chain and the candidate are valid.
          // Just going until the active chain is an optimization, as we know all blocks in it are valid already.
          CBlockIndex *pindexTest = pindexNew;
          bool fInvalidAncestor = false;
          while (pindexTest && !chainActive.Contains(pindexTest)) {
              assert(pindexTest->nChainTx || pindexTest->nHeight == 0);
  
              // Pruned nodes may have entries in setBlockIndexCandidates for
              // which block files have been deleted.  Remove those as candidates
              // for the most work chain if we come across them; we can't switch
              // to a chain unless we have all the non-active-chain parent blocks.
              bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK;
              bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA);
              if (fFailedChain || fMissingData) {
                  // Candidate chain is not usable (either invalid or missing data)
                  if (fFailedChain && (pindexBestInvalid == NULL || pindexNew->nChainWork > pindexBestInvalid->nChainWork))
                      pindexBestInvalid = pindexNew;
                  CBlockIndex *pindexFailed = pindexNew;
                  // Remove the entire chain from the set.
                  while (pindexTest != pindexFailed) {
                      if (fFailedChain) {
                          pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                      } else if (fMissingData) {
                          // If we're missing data, then add back to mapBlocksUnlinked,
                          // so that if the block arrives in the future we can try adding
                          // to setBlockIndexCandidates again.
                          mapBlocksUnlinked.insert(std::make_pair(pindexFailed->pprev, pindexFailed));
                      }
                      setBlockIndexCandidates.erase(pindexFailed);
                      pindexFailed = pindexFailed->pprev;
                  }
                  setBlockIndexCandidates.erase(pindexTest);
                  fInvalidAncestor = true;
                  break;
              }
              pindexTest = pindexTest->pprev;
          }
          if (!fInvalidAncestor)
              return pindexNew;
      } while(true);
  }
  
  /** Delete all entries in setBlockIndexCandidates that are worse than the current tip. */
  static void PruneBlockIndexCandidates() {
      // Note that we can't delete the current block itself, as we may need to return to it later in case a
      // reorganization to a better block fails.
      std::set<CBlockIndex*, CBlockIndexWorkComparator>::iterator it = setBlockIndexCandidates.begin();
      while (it != setBlockIndexCandidates.end() && setBlockIndexCandidates.value_comp()(*it, chainActive.Tip())) {
          setBlockIndexCandidates.erase(it++);
      }
      // Either the current tip or a successor of it we're working towards is left in setBlockIndexCandidates.
      assert(!setBlockIndexCandidates.empty());
  }
  
  /**
   * Try to make some progress towards making pindexMostWork the active block.
   * pblock is either NULL or a pointer to a CBlock corresponding to pindexMostWork.
   */
  static bool ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const CBlock* pblock, bool& fInvalidFound)
  {
      AssertLockHeld(cs_main);
      const CBlockIndex *pindexOldTip = chainActive.Tip();
      const CBlockIndex *pindexFork = chainActive.FindFork(pindexMostWork);
  
      // Disconnect active blocks which are no longer in the best chain.
      bool fBlocksDisconnected = false;
      while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
          if (!DisconnectTip(state, chainparams))
              return false;
          fBlocksDisconnected = true;
      }
  
      // Build list of new blocks to connect.
      std::vector<CBlockIndex*> vpindexToConnect;
      bool fContinue = true;
      int nHeight = pindexFork ? pindexFork->nHeight : -1;
      while (fContinue && nHeight != pindexMostWork->nHeight) {
          // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need
          // a few blocks along the way.
          int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
          vpindexToConnect.clear();
          vpindexToConnect.reserve(nTargetHeight - nHeight);
          CBlockIndex *pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
          while (pindexIter && pindexIter->nHeight != nHeight) {
              vpindexToConnect.push_back(pindexIter);
              pindexIter = pindexIter->pprev;
          }
          nHeight = nTargetHeight;
  
          // Connect new blocks.
          BOOST_REVERSE_FOREACH(CBlockIndex *pindexConnect, vpindexToConnect) {
              if (!ConnectTip(state, chainparams, pindexConnect, pindexConnect == pindexMostWork ? pblock : NULL)) {
                  if (state.IsInvalid()) {
                      // The block violates a consensus rule.
                      if (!state.CorruptionPossible())
                          InvalidChainFound(vpindexToConnect.back());
                      state = CValidationState();
                      fInvalidFound = true;
                      fContinue = false;
                      break;
                  } else {
                      // A system error occurred (disk space, database error, ...).
                      return false;
                  }
              } else {
                  PruneBlockIndexCandidates();
                  if (!pindexOldTip || chainActive.Tip()->nChainWork > pindexOldTip->nChainWork) {
                      // We're in a better position than we were. Return temporarily to release the lock.
                      fContinue = false;
                      break;
                  }
              }
          }
      }
  
      if (fBlocksDisconnected) {
          mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
          LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
      }
      mempool.check(pcoinsTip);
  
      // Callbacks/notifications for a new best chain.
      if (fInvalidFound)
          CheckForkWarningConditionsOnNewFork(vpindexToConnect.back());
      else
          CheckForkWarningConditions();
  
      return true;
  }
  
  static void NotifyHeaderTip() {
      bool fNotify = false;
      bool fInitialBlockDownload = false;
      static CBlockIndex* pindexHeaderOld = NULL;
      {
          LOCK(cs_main);
          if (pindexBestHeader != pindexHeaderOld) {
              fNotify = true;
              fInitialBlockDownload = IsInitialBlockDownload();
              pindexHeaderOld = pindexBestHeader;
          }
      }
      // Send block tip changed notifications without cs_main
      if (fNotify) {
          uiInterface.NotifyHeaderTip(fInitialBlockDownload, pindexBestHeader);
      }
  }
  
  /**
   * Make the best chain active, in multiple steps. The result is either failure
   * or an activated best chain. pblock is either NULL or a pointer to a block
   * that is already loaded (to avoid loading it again from disk).
   */
  bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, const CBlock *pblock) {
      CBlockIndex *pindexMostWork = NULL;
      CBlockIndex *pindexNewTip = NULL;
      do {
          boost::this_thread::interruption_point();
          if (ShutdownRequested())
              break;
  
          const CBlockIndex *pindexFork;
          bool fInitialDownload;
          int nNewHeight;
          {
              LOCK(cs_main);
              CBlockIndex *pindexOldTip = chainActive.Tip();
              if (pindexMostWork == NULL) {
                  pindexMostWork = FindMostWorkChain();
              }
  
              // Whether we have anything to do at all.
              if (pindexMostWork == NULL || pindexMostWork == chainActive.Tip())
                  return true;
  
              bool fInvalidFound = false;
              if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : NULL, fInvalidFound))
                  return false;
  
              if (fInvalidFound) {
                  // Wipe cache, we may need another branch now.
                  pindexMostWork = NULL;
              }
              pindexNewTip = chainActive.Tip();
              pindexFork = chainActive.FindFork(pindexOldTip);
              fInitialDownload = IsInitialBlockDownload();
              nNewHeight = chainActive.Height();
          }
          // When we reach this point, we switched to a new tip (stored in pindexNewTip).
  
          // Notifications/callbacks that can run without cs_main
          // Always notify the UI if a new block tip was connected
          if (pindexFork != pindexNewTip) {
              uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
  
              if (!fInitialDownload) {
                  // Find the hashes of all blocks that weren't previously in the best chain.
                  std::vector<uint256> vHashes;
                  CBlockIndex *pindexToAnnounce = pindexNewTip;
                  while (pindexToAnnounce != pindexFork) {
                      vHashes.push_back(pindexToAnnounce->GetBlockHash());
                      pindexToAnnounce = pindexToAnnounce->pprev;
                      if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
                          // Limit announcements in case of a huge reorganization.
                          // Rely on the peer's synchronization mechanism in that case.
                          break;
                      }
                  }
                  // Relay inventory, but don't relay old inventory during initial block download.
                  int nBlockEstimate = 0;
                  if (fCheckpointsEnabled)
                      nBlockEstimate = Checkpoints::GetTotalBlocksEstimate(chainparams.Checkpoints());
                  {
                      LOCK(cs_vNodes);
                      BOOST_FOREACH(CNode* pnode, vNodes) {
                          if (nNewHeight > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : nBlockEstimate)) {
                              BOOST_REVERSE_FOREACH(const uint256& hash, vHashes) {
                                  pnode->PushBlockHash(hash);
                              }
                          }
                      }
                  }
                  // Notify external listeners about the new tip.
                  if (!vHashes.empty()) {
                      GetMainSignals().UpdatedBlockTip(pindexNewTip);
                  }
              }
          }
      } while (pindexNewTip != pindexMostWork);
      CheckBlockIndex(chainparams.GetConsensus());
  
      // Write changes periodically to disk, after relay.
      if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC)) {
          return false;
      }
  
      return true;
  }
  
  bool InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex)
  {
      AssertLockHeld(cs_main);
  
      // Mark the block itself as invalid.
      pindex->nStatus |= BLOCK_FAILED_VALID;
      setDirtyBlockIndex.insert(pindex);
      setBlockIndexCandidates.erase(pindex);
  
      while (chainActive.Contains(pindex)) {
          CBlockIndex *pindexWalk = chainActive.Tip();
          pindexWalk->nStatus |= BLOCK_FAILED_CHILD;
          setDirtyBlockIndex.insert(pindexWalk);
          setBlockIndexCandidates.erase(pindexWalk);
          // ActivateBestChain considers blocks already in chainActive
          // unconditionally valid already, so force disconnect away from it.
          if (!DisconnectTip(state, chainparams)) {
              mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
              return false;
          }
      }
  
      LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
  
      // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
      // add it again.
      BlockMap::iterator it = mapBlockIndex.begin();
      while (it != mapBlockIndex.end()) {
          if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
              setBlockIndexCandidates.insert(it->second);
          }
          it++;
      }
  
      InvalidChainFound(pindex);
      mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
      return true;
  }
  
  bool ResetBlockFailureFlags(CBlockIndex *pindex) {
      AssertLockHeld(cs_main);
  
      int nHeight = pindex->nHeight;
  
      // Remove the invalidity flag from this block and all its descendants.
      BlockMap::iterator it = mapBlockIndex.begin();
      while (it != mapBlockIndex.end()) {
          if (!it->second->IsValid() && it->second->GetAncestor(nHeight) == pindex) {
              it->second->nStatus &= ~BLOCK_FAILED_MASK;
              setDirtyBlockIndex.insert(it->second);
              if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && setBlockIndexCandidates.value_comp()(chainActive.Tip(), it->second)) {
                  setBlockIndexCandidates.insert(it->second);
              }
              if (it->second == pindexBestInvalid) {
                  // Reset invalid block marker if it was pointing to one of those.
                  pindexBestInvalid = NULL;
              }
          }
          it++;
      }
  
      // Remove the invalidity flag from all ancestors too.
      while (pindex != NULL) {
          if (pindex->nStatus & BLOCK_FAILED_MASK) {
              pindex->nStatus &= ~BLOCK_FAILED_MASK;
              setDirtyBlockIndex.insert(pindex);
          }
          pindex = pindex->pprev;
      }
      return true;
  }
  
  CBlockIndex* AddToBlockIndex(const CBlockHeader& block)
  {
      // Check for duplicate
      uint256 hash = block.GetHash();
      BlockMap::iterator it = mapBlockIndex.find(hash);
      if (it != mapBlockIndex.end())
          return it->second;
  
      // Construct new block index object
      CBlockIndex* pindexNew = new CBlockIndex(block);
      assert(pindexNew);
      // We assign the sequence id to blocks only when the full data is available,
      // to avoid miners withholding blocks but broadcasting headers, to get a
      // competitive advantage.
      pindexNew->nSequenceId = 0;
      BlockMap::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
      pindexNew->phashBlock = &((*mi).first);
      BlockMap::iterator miPrev = mapBlockIndex.find(block.hashPrevBlock);
      if (miPrev != mapBlockIndex.end())
      {
          pindexNew->pprev = (*miPrev).second;
          pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
          pindexNew->BuildSkip();
      }
  
      // ppcoin: compute chain trust score
      pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
  
      if (pindexBestHeader == NULL || pindexBestHeader->nChainWork < pindexNew->nChainWork)
          pindexBestHeader = pindexNew;
  
      pindexNew->RaiseValidity(BLOCK_VALID_TREE);
      setDirtyBlockIndex.insert(pindexNew);
  
      return pindexNew;
  }
  
  /** Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS). */
  bool ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos)
  {
      pindexNew->nTx = block.vtx.size();
      pindexNew->nChainTx = 0;
      pindexNew->nFile = pos.nFile;
      pindexNew->nDataPos = pos.nPos;
      pindexNew->nUndoPos = 0;
      pindexNew->nStatus |= BLOCK_HAVE_DATA;
      if (IsWitnessEnabled(pindexNew->pprev, Params().GetConsensus())) {
          pindexNew->nStatus |= BLOCK_OPT_WITNESS;
      }
      pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
      setDirtyBlockIndex.insert(pindexNew);
  
      if (pindexNew->pprev == NULL || pindexNew->pprev->nChainTx) {
          // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS.
          deque<CBlockIndex*> queue;
          queue.push_back(pindexNew);
  
          // Recursively process any descendant blocks that now may be eligible to be connected.
          while (!queue.empty()) {
              CBlockIndex *pindex = queue.front();
              queue.pop_front();
              pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
              {
                  LOCK(cs_nBlockSequenceId);
                  pindex->nSequenceId = nBlockSequenceId++;
              }
              if (chainActive.Tip() == NULL || !setBlockIndexCandidates.value_comp()(pindex, chainActive.Tip())) {
                  setBlockIndexCandidates.insert(pindex);
              }
              std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex);
              while (range.first != range.second) {
                  std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first;
                  queue.push_back(it->second);
                  range.first++;
                  mapBlocksUnlinked.erase(it);
              }
          }
      } else {
          if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) {
              mapBlocksUnlinked.insert(std::make_pair(pindexNew->pprev, pindexNew));
          }
      }
  
      return true;
  }
  
  bool FindBlockPos(CValidationState &state, CDiskBlockPos &pos, unsigned int nAddSize, unsigned int nHeight, uint64_t nTime, bool fKnown = false)
  {
      LOCK(cs_LastBlockFile);
  
      unsigned int nFile = fKnown ? pos.nFile : nLastBlockFile;
      if (vinfoBlockFile.size() <= nFile) {
          vinfoBlockFile.resize(nFile + 1);
      }
  
      if (!fKnown) {
          while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
              nFile++;
              if (vinfoBlockFile.size() <= nFile) {
                  vinfoBlockFile.resize(nFile + 1);
              }
          }
          pos.nFile = nFile;
          pos.nPos = vinfoBlockFile[nFile].nSize;
      }
  
      if ((int)nFile != nLastBlockFile) {
          if (!fKnown) {
              LogPrintf("Leaving block file %i: %s\n", nLastBlockFile, vinfoBlockFile[nLastBlockFile].ToString());
          }
          FlushBlockFile(!fKnown);
          nLastBlockFile = nFile;
      }
  
      vinfoBlockFile[nFile].AddBlock(nHeight, nTime);
      if (fKnown)
          vinfoBlockFile[nFile].nSize = std::max(pos.nPos + nAddSize, vinfoBlockFile[nFile].nSize);
      else
          vinfoBlockFile[nFile].nSize += nAddSize;
  
      if (!fKnown) {
          unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
          unsigned int nNewChunks = (vinfoBlockFile[nFile].nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
          if (nNewChunks > nOldChunks) {
              if (fPruneMode)
                  fCheckForPruning = true;
              if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                  FILE *file = OpenBlockFile(pos);
                  if (file) {
                      LogPrintf("Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
                      AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
                      fclose(file);
                  }
              }
              else
                  return state.Error("out of disk space");
          }
      }
  
      setDirtyFileInfo.insert(nFile);
      return true;
  }
  
  bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigned int nAddSize)
  {
      pos.nFile = nFile;
  
      LOCK(cs_LastBlockFile);
  
      unsigned int nNewSize;
      pos.nPos = vinfoBlockFile[nFile].nUndoSize;
      nNewSize = vinfoBlockFile[nFile].nUndoSize += nAddSize;
      setDirtyFileInfo.insert(nFile);
  
      unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
      unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
      if (nNewChunks > nOldChunks) {
          if (fPruneMode)
              fCheckForPruning = true;
          if (CheckDiskSpace(nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos)) {
              FILE *file = OpenUndoFile(pos);
              if (file) {
                  LogPrintf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
                  AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
                  fclose(file);
              }
          }
          else
              return state.Error("out of disk space");
      }
  
      return true;
  }
  
  bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW)
  {
      // Check proof of work matches claimed amount
      CBlockIndex pblock = CBlockIndex(block);
      if (pblock.IsProofOfWork())
          if (!CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
              return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");
  
      return true;
  }
  
  bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig)
  {
      // These are checks that are independent of context.
      if (block.fChecked)
          return true;
  
      // Check that the header is valid (particularly PoW).  This is mostly
      // redundant with the call in AcceptBlockHeader.
      if(block.IsProofOfWork())
          if (!CheckBlockHeader(block, state, consensusParams, false))
              return false;
  
      // Check the merkle root.
      if (fCheckMerkleRoot) {
          bool mutated;
          uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
  
          if (block.hashMerkleRoot != hashMerkleRoot2)
              return state.DoS(100, false, REJECT_INVALID, "bad-txnmrklroot", true, "hashMerkleRoot mismatch");
  
          // Check for merkle tree malleability (CVE-2012-2459): repeating sequences
          // of transactions in a block without affecting the merkle root of a block,
          // while still invalidating it.
          if (mutated)
              return state.DoS(100, false, REJECT_INVALID, "bad-txns-duplicate", true, "duplicate transaction");
      }
  
      if (block.IsProofOfStake())
      {
          // Second transaction must be coinstake, the rest must not be
          if (block.vtx.empty() || !block.vtx[1].IsCoinStake())
              return state.DoS(100, error("CheckBlock() : second tx is not coinstake"));
          for (unsigned int i = 2; i < block.vtx.size(); i++)
              if (block.vtx[i].IsCoinStake())
                  return state.DoS(100, error("CheckBlock() : more than one coinstake"));
      }
  
      // All potential-corruption validation must be done before we do any
      // transaction validation, as otherwise we may mark the header as invalid
      // because we receive the wrong transactions for it.
      // Note that witness malleability is checked in ContextualCheckBlock, so no
      // checks that use witness data may be performed here.
  
      // Size limits
      if (block.vtx.empty() || block.vtx.size() > MAX_BLOCK_BASE_SIZE || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) > MAX_BLOCK_BASE_SIZE)
          return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false, "size limits failed");
  
      // First transaction must be coinbase, the rest must not be
      if (block.vtx.empty() || !block.vtx[0].IsCoinBase())
          return state.DoS(100, false, REJECT_INVALID, "bad-cb-missing", false, "first tx is not coinbase");
      for (unsigned int i = 1; i < block.vtx.size(); i++)
          if (block.vtx[i].IsCoinBase())
              return state.DoS(100, false, REJECT_INVALID, "bad-cb-multiple", false, "more than one coinbase");
  
      // Check proof-of-stake block signature
      if (fCheckSig && !CheckBlockSignature(block))
      {
          return error("CheckBlock() : bad proof-of-stake block signature");
      }
  
      bool fColdStakingEnabled = IsColdStakingEnabled(chainActive.Tip(), Params().GetConsensus());
  
      // Check transactions
      BOOST_FOREACH(const CTransaction& tx, block.vtx)
      {
          if (!CheckTransaction(tx, state))
              return state.Invalid(false, state.GetRejectCode(), state.GetRejectReason(),
                                   strprintf("Transaction check failed (tx hash %s) %s\n%s", tx.GetHash().ToString(), state.GetDebugMessage(), tx.ToString()));
  
          if (!fColdStakingEnabled)
          {
              for (const CTxOut& txout: tx.vout)
                  if(txout.scriptPubKey.IsColdStaking())
                      return state.DoS(100, false, REJECT_INVALID, "cold-staking-not-enabled");
          }
      }
  
      unsigned int nSigOps = 0;
      BOOST_FOREACH(const CTransaction& tx, block.vtx)
          nSigOps += GetLegacySigOpCount(tx);
  
      if (nSigOps * WITNESS_SCALE_FACTOR > MAX_BLOCK_SIGOPS_COST)
          return state.DoS(100, false, REJECT_INVALID, "bad-blk-sigops", false, "out-of-bounds SigOpCount");
  
      if (fCheckMerkleRoot)
          block.fChecked = true;
  
      return true;
  }
  
  bool CheckBlockSignature(const CBlock& block)
  {
      if (block.IsProofOfWork())
      {
          return block.vchBlockSig.empty() ? true : error("CheckBlockSignature: Bad Block - can't check signature of a proof of work block\n");
      }
  
      if (block.vchBlockSig.empty())
      {
          return error("CheckBlockSignature: Bad Block - vchBlockSig empty\n");
      }
  
      vector<std::vector<unsigned char>> vSolutions;
      txnouttype whichType;
  
      const CTxOut& txout = block.vtx[1].vout[1];
  
      if (!Solver(txout.scriptPubKey, whichType, vSolutions))
      {
          LogPrintf("CheckBlockSignature: Bad Block - wrong signature\n");
          return false;
      }
  
      if (whichType == TX_PUBKEY)
      {
          std::vector<unsigned char>& vchPubKey = vSolutions[0];
          return CPubKey(vchPubKey).Verify(block.GetHash(), block.vchBlockSig);
      }
  
      if(whichType == TX_COLDSTAKING) // We need to get the public key from the input's scriptSig
      {
          if(block.vtx[1].vin[0].scriptSig.size() <= 0x21)
              return false;
  
          vector<unsigned char> signerPubKey(block.vtx[1].vin[0].scriptSig.end()-0x21,block.vtx[1].vin[0].scriptSig.end());
          return CPubKey(signerPubKey).Verify(block.GetHash(), block.vchBlockSig);
      }
  
      LogPrintf("CheckBlockSignature: Unknown type\n");
      return false;
  }
  
  static bool CheckIndexAgainstCheckpoint(const CBlockIndex* pindexPrev, CValidationState& state, const CChainParams& chainparams, const uint256& hash)
  {
      if (*pindexPrev->phashBlock == chainparams.GetConsensus().hashGenesisBlock)
          return true;
  
      int nHeight = pindexPrev->nHeight+1;
      // Don't accept any forks from the main chain prior to last checkpoint
      CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(chainparams.Checkpoints());
      if (pcheckpoint && nHeight < pcheckpoint->nHeight)
          return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight));
  
      return true;
  }
  
  bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsWitnessLocked(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_LOCKED_IN);
  }
  
  bool IsCommunityFundEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COMMUNITYFUND, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsReducedCFundQuorumEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_QUORUM_CFUND, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsCommunityFundAccumulationEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params, bool fStrict)
  {
      LOCK(cs_main);
      return (IsCommunityFundEnabled(pindexPrev, params) && !fStrict) ||
            (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COMMUNITYFUND_ACCUMULATION, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsCommunityFundAmountV2Enabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COMMUNITYFUND_AMOUNT_V2, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsCommunityFundAccumulationSpreadEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COMMUNITYFUND_ACCUMULATION_SPREAD, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsNtpSyncEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_NTPSYNC, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsCommunityFundLocked(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COMMUNITYFUND, versionbitscache) == THRESHOLD_LOCKED_IN);
  }
  
  bool IsColdStakingEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_COLDSTAKING, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  bool IsStaticRewardLocked(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_STATIC_REWARD, versionbitscache) == THRESHOLD_LOCKED_IN);
  }
  
  bool IsStaticRewardEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
  {
      LOCK(cs_main);
      return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_STATIC_REWARD, versionbitscache) == THRESHOLD_ACTIVE);
  }
  
  // Compute at which vout of the block's coinbase transaction the witness
  // commitment occurs, or -1 if not found.
  static int GetWitnessCommitmentIndex(const CBlock& block)
  {
      int commitpos = -1;
      for (size_t o = 0; o < block.vtx[0].vout.size(); o++) {
          if (block.vtx[0].vout[o].scriptPubKey.size() >= 38 && block.vtx[0].vout[o].scriptPubKey[0] == OP_RETURN && block.vtx[0].vout[o].scriptPubKey[1] == 0x24 && block.vtx[0].vout[o].scriptPubKey[2] == 0xaa && block.vtx[0].vout[o].scriptPubKey[3] == 0x21 && block.vtx[0].vout[o].scriptPubKey[4] == 0xa9 && block.vtx[0].vout[o].scriptPubKey[5] == 0xed) {
              commitpos = o;
          }
      }
      return commitpos;
  }
  
  void UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams)
  {
      int commitpos = GetWitnessCommitmentIndex(block);
      static const std::vector<unsigned char> nonce(32, 0x00);
      if (commitpos != -1 && IsWitnessEnabled(pindexPrev, consensusParams) && block.vtx[0].wit.IsEmpty()) {
          block.vtx[0].wit.vtxinwit.resize(1);
          block.vtx[0].wit.vtxinwit[0].scriptWitness.stack.resize(1);
          block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0] = nonce;
      }
  }
  
  std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams)
  {
      std::vector<unsigned char> commitment;
      int commitpos = GetWitnessCommitmentIndex(block);
      bool fHaveWitness = false;
      for (size_t t = 1; t < block.vtx.size(); t++) {
          if (!block.vtx[t].wit.IsNull()) {
              fHaveWitness = true;
              break;
          }
      }
      std::vector<unsigned char> ret(32, 0x00);
      if (fHaveWitness && IsWitnessEnabled(pindexPrev, consensusParams)) {
          if (commitpos == -1) {
              uint256 witnessroot = BlockWitnessMerkleRoot(block, NULL);
              CHash256().Write(witnessroot.begin(), 32).Write(&ret[0], 32).Finalize(witnessroot.begin());
              CTxOut out;
              out.nValue = 0;
              out.scriptPubKey.resize(38);
              out.scriptPubKey[0] = OP_RETURN;
              out.scriptPubKey[1] = 0x24;
              out.scriptPubKey[2] = 0xaa;
              out.scriptPubKey[3] = 0x21;
              out.scriptPubKey[4] = 0xa9;
              out.scriptPubKey[5] = 0xed;
              memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
              commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
              const_cast<std::vector<CTxOut>*>(&block.vtx[0].vout)->push_back(out);
              block.vtx[0].UpdateHash();
          }
      }
      UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams);
      return commitment;
  }
  
  bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, CBlockIndex * const pindexPrev, int64_t nAdjustedTime)
  {
  
      // Check timestamp
      if (block.GetBlockTime() > nAdjustedTime + (IsNtpSyncEnabled(pindexPrev,Params().GetConsensus()) ? Params().GetConsensus().nMaxFutureDrift : 2 * 60 * 60))
          return state.Invalid(false, REJECT_INVALID, "time-too-new", "block timestamp too far in the future");
  
      // Reject outdated version blocks when 95% (75% on testnet) of the network has upgraded:
      for (int32_t version = 2; version < 5; ++version) // check for version 2, 3 and 4 upgrades
          if (block.nVersion < version && IsSuperMajority(version, pindexPrev, consensusParams.nMajorityRejectBlockOutdated, consensusParams))
              return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", version - 1),
                                   strprintf("rejected nVersion=0x%08x block", version - 1));
  
      if((block.nVersion & VERSIONBITS_TOP_BITS_SIG) != VERSIONBITS_TOP_BITS_SIG && IsSigHFEnabled(Params().GetConsensus(), pindexPrev))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no sig block");
  
      if((block.nVersion & nSegWitVersionMask) != nSegWitVersionMask && IsWitnessEnabled(pindexPrev,Params().GetConsensus()))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no segwit block");
  
      if((block.nVersion & nCFundVersionMask) != nCFundVersionMask && IsCommunityFundEnabled(pindexPrev,Params().GetConsensus()))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no cfund block");
  
      if(!GetBoolArg("-testnet",false)) {
          if((block.nVersion & nCFundAccVersionMask) != nCFundAccVersionMask && IsCommunityFundAccumulationEnabled(pindexPrev,Params().GetConsensus(), true))
              return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                                 "rejected no cfund accumulation block");
          if((block.nVersion & nColdStakingVersionMask) != nColdStakingVersionMask && IsColdStakingEnabled(pindexPrev,Params().GetConsensus()))
              return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                                 "rejected no cold-staking block");
      }
  
      if((block.nVersion & nCFundAccSpreadVersionMask) != nCFundAccSpreadVersionMask && IsCommunityFundAccumulationSpreadEnabled(pindexPrev,Params().GetConsensus()))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no cfund accumulation spread block");
  
      if((block.nVersion & nCFundAmountV2Mask) != nCFundAmountV2Mask && IsCommunityFundAmountV2Enabled(pindexPrev,Params().GetConsensus()))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no cfund amount v2 block");
  
      if((block.nVersion & nNSyncVersionMask) != nNSyncVersionMask && IsNtpSyncEnabled(pindexPrev,Params().GetConsensus()))
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                             "rejected no nsync block");
  
     if((block.nVersion & nStaticRewardVersionMask) != nStaticRewardVersionMask && IsStaticRewardEnabled(pindexPrev,Params().GetConsensus()))
       return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                          "rejected no static reward block");
  
     if((block.nVersion & nCFundReducedQuorumMask) != nCFundReducedQuorumMask && IsReducedCFundQuorumEnabled(pindexPrev,Params().GetConsensus()))
         return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                          "rejected no reduced quorum block");
  
     if((block.nVersion & nV451ForkMask) != nV451ForkMask && pindexPrev->nHeight >= Params().GetConsensus().nHeightv451Fork)
         return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                          "rejected, block version isn't v4.5.1");
  
      if((block.nVersion & nV452ForkMask) != nV452ForkMask && pindexPrev->nHeight >= Params().GetConsensus().nHeightv452Fork)
          return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                           "rejected, block version isn't v4.5.2");
      
      return true;
  }
  
  bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIndex * const pindexPrev, bool fProofOfStake)
  {
      const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
      const Consensus::Params& consensusParams = Params().GetConsensus();
  
      // Start enforcing BIP113 (Median Time Past) using versionbits logic.
      int nLockTimeFlags = 0;
      if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
          nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
      }
  
      if (block.IsProofOfWork() && nHeight > Params().GetConsensus().nLastPOWBlock)
          return state.DoS(10, false, REJECT_INVALID, "check-pow-height", "pow-mined blocks not allowed");
  
      if (IsNtpSyncEnabled(pindexPrev,Params().GetConsensus()) && block.GetBlockTime() < pindexPrev->GetPastTimeLimit())
          return state.Invalid(false, REJECT_INVALID, "too-old", "block goes too far in the past");
  
      // Check CheckCoinStakeTimestamp
      if (block.IsProofOfStake() && !CheckCoinStakeTimestamp(nHeight, block.GetBlockTime(), (int64_t)block.vtx[1].nTime))
          return state.Invalid(false, REJECT_INVALID, "check-coinstake-timestamp", "coinstake timestamp violation");
  
      int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
                                ? pindexPrev->GetMedianTimePast()
                                : block.GetBlockTime();
  
      // Check that all transactions are finalized
      BOOST_FOREACH(const CTransaction& tx, block.vtx) {
          if (!IsFinalTx(tx, nHeight, nLockTimeCutoff)) {
              return state.DoS(10, false, REJECT_INVALID, "bad-txns-nonfinal", false, "non-final transaction");
          }
      }
  
      // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height
      // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
      if (block.nVersion >= 2 && IsSuperMajority(2, pindexPrev, consensusParams.nMajorityEnforceBlockUpgrade, consensusParams))
      {
          CScript expect = CScript() << nHeight;
          if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
              !std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin())) {
              return state.DoS(100, false, REJECT_INVALID, "bad-cb-height", false, "block height mismatch in coinbase");
          }
      }
  
      // Validation for witness commitments.
      // * We compute the witness hash (which is the hash including witnesses) of all the block's transactions, except the
      //   coinbase (where 0x0000....0000 is used instead).
      // * The coinbase scriptWitness is a stack of a single 32-byte vector, containing a witness nonce (unconstrained).
      // * We build a merkle tree with all those witness hashes as leaves (similar to the hashMerkleRoot in the block header).
      // * There must be at least one output whose scriptPubKey is a single 36-byte push, the first 4 bytes of which are
      //   {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness nonce). In case there are
      //   multiple, the last one is used.
      bool fHaveWitness = false;
      if (IsWitnessEnabled(pindexPrev, consensusParams)) {
          int commitpos = GetWitnessCommitmentIndex(block);
          if (commitpos != -1) {
              bool malleated = false;
              uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated, true);
              // The malleation check is ignored; as the transaction tree itself
              // already does not permit it, it is impossible to trigger in the
              // witness tree.
              if (block.vtx[0].wit.vtxinwit.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0].size() != 32) {
                  return state.DoS(100, error("%s : invalid witness nonce size", __func__), REJECT_INVALID, "bad-witness-nonce-size", true);
              }
              CHash256().Write(hashWitness.begin(), 32).Write(&block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0][0], 32).Finalize(hashWitness.begin());
              if (memcmp(hashWitness.begin(), &block.vtx[0].vout[commitpos].scriptPubKey[6], 32)) {
                  return state.DoS(100, error("%s : witness merkle commitment mismatch", __func__), REJECT_INVALID, "bad-witness-merkle-match", true);
              }
              fHaveWitness = true;
          }
      }
  
      // No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam
      if (!fHaveWitness) {
          for (size_t i = 0; i < block.vtx.size(); i++) {
              if (!block.vtx[i].wit.IsNull()) {
                  return state.DoS(100, error("%s : unexpected witness data found", __func__), REJECT_INVALID, "unexpected-witness", true);
              }
          }
      }
  
      // After the coinbase witness nonce and commitment are verified,
      // we can check if the block weight passes (before we've checked the
      // coinbase witness, it would be possible for the weight to be too
      // large by filling up the coinbase witness, which doesn't change
      // the block hash, so we couldn't mark the block as permanently
      // failed).
      if (GetBlockWeight(block) > MAX_BLOCK_WEIGHT) {
          return state.DoS(100, error("ContextualCheckBlock(): weight limit failed"), REJECT_INVALID, "bad-blk-weight");
      }
  
      return true;
  }
  
  static bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex=NULL)
  {
      AssertLockHeld(cs_main);
      // Check for duplicate
      uint256 hash = block.GetHash();
      BlockMap::iterator miSelf = mapBlockIndex.find(hash);
      CBlockIndex *pindex = NULL;
      if (hash != chainparams.GetConsensus().hashGenesisBlock) {
  
          if (miSelf != mapBlockIndex.end()) {
              // Block header is already known.
              pindex = miSelf->second;
              if (ppindex)
                  *ppindex = pindex;
              if (pindex->nStatus & BLOCK_FAILED_MASK)
                  return state.Invalid(error("%s: block %s is marked invalid", __func__, hash.ToString()), 0, "duplicate");
              return true;
          }
  
          if (!CheckBlockHeader(block, state, chainparams.GetConsensus(), false))
              return error("%s: Consensus::CheckBlockHeader: %s, %s", __func__, hash.ToString(), FormatStateMessage(state));
  
          // Get prev block index
          CBlockIndex* pindexPrev = NULL;
          BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
          if (mi == mapBlockIndex.end())
              return state.DoS(10, error("%s: prev block not found", __func__), 0, "bad-prevblk");
          pindexPrev = (*mi).second;
          if (pindexPrev->nStatus & BLOCK_FAILED_MASK)
              return state.DoS(100, error("%s: prev block invalid", __func__), REJECT_INVALID, "bad-prevblk");
  
          assert(pindexPrev);
          if (fCheckpointsEnabled && !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams, hash))
              return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__, state.GetRejectReason().c_str());
  
          if (!ContextualCheckBlockHeader(block, state, chainparams.GetConsensus(), pindexPrev, GetAdjustedTime()))
              return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s", __func__, hash.ToString(), FormatStateMessage(state));
  
      }
  
      if (pindex == NULL)
          pindex = AddToBlockIndex(block);
  
      if (ppindex)
          *ppindex = pindex;
  
      return true;
  }
  
  /** Store block on disk. If dbp is non-NULL, the file is known to already reside on disk */
  static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock)
  {
      if (fNewBlock) *fNewBlock = false;
      AssertLockHeld(cs_main);
  
      CBlockIndex *pindexDummy = NULL;
      CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy;
  
      if (!AcceptBlockHeader(block, state, chainparams, &pindex))
          return false;
  
      // Try to process all requested blocks that we don't have, but only
      // process an unrequested block if it's new and has enough work to
      // advance our tip, and isn't too many blocks ahead.
      bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
      bool fHasMoreWork = (chainActive.Tip() ? pindex->nChainWork > chainActive.Tip()->nChainWork : true);
      // Blocks that are too out-of-order needlessly limit the effectiveness of
      // pruning, because pruning will not delete block files that contain any
      // blocks which are too close in height to the tip.  Apply this test
      // regardless of whether pruning is enabled; it should generally be safe to
      // not process unrequested blocks.
      bool fTooFarAhead = (pindex->nHeight > int(chainActive.Height() + MIN_BLOCKS_TO_KEEP));
  
      // TODO: deal better with return value and error conditions for duplicate
      // and unrequested blocks.
      if (fAlreadyHave) return true;
      if (!fRequested) {  // If we didn't ask for it:
          if (pindex->nTx != 0) return true;  // This is a previously-processed block that was pruned
          if (!fHasMoreWork) return true;     // Don't process less-work chains
          if (fTooFarAhead) return true;      // Block height is too high
      }
      if (fNewBlock) *fNewBlock = true;
  
      if ((!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime())) || !ContextualCheckBlock(block, state, pindex->pprev)) {
          if (state.IsInvalid() && !state.CorruptionPossible()) {
              pindex->nStatus |= BLOCK_FAILED_VALID;
              setDirtyBlockIndex.insert(pindex);
          }
          return error("%s: %s", __func__, FormatStateMessage(state));
      }
  
      int nHeight = pindex->nHeight;
  
      // Write block to history file
      try {
          unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
          CDiskBlockPos blockPos;
          if (dbp != NULL)
              blockPos = *dbp;
          if (!FindBlockPos(state, blockPos, nBlockSize+8, nHeight, block.GetBlockTime(), dbp != NULL))
              return error("AcceptBlock(): FindBlockPos failed");
          if (dbp == NULL)
              if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
                  AbortNode(state, "Failed to write block");
          if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
              return error("AcceptBlock(): ReceivedBlockTransactions failed");
      } catch (const std::runtime_error& e) {
          return AbortNode(state, std::string("System error: ") + e.what());
      }
  
      if (fCheckForPruning)
          FlushStateToDisk(state, FLUSH_STATE_NONE); // we just allocated more disk space for block files
  
      return true;
  }
  
  static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned nRequired, const Consensus::Params& consensusParams)
  {
      unsigned int nFound = 0;
      for (int i = 0; i < consensusParams.nMajorityWindow && nFound < nRequired && pstart != NULL; i++)
      {
          if (pstart->nVersion >= minVersion)
              ++nFound;
          pstart = pstart->pprev;
      }
      return (nFound >= nRequired);
  }
  
  
  bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp)
  {
      {
          LOCK(cs_main);
          bool fRequested = MarkBlockAsReceived(pblock->GetHash());
          fRequested |= fForceProcessing;
  
          // Store to disk
          CBlockIndex *pindex = NULL;
          bool fNewBlock = false;
  
          bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fRequested, dbp, &fNewBlock);
          if (pindex && pfrom) {
              mapBlockSource[pindex->GetBlockHash()] = pfrom->GetId();
              if (fNewBlock) pfrom->nLastBlockTime = GetTime();
          }
  
          CheckBlockIndex(chainparams.GetConsensus());
  
          if (!ret)
              return error("%s: AcceptBlock FAILED", __func__);
      }
  
      NotifyHeaderTip();
  
      if (!ActivateBestChain(state, chainparams, pblock)){
        return error("%s: ActivateBestChain failed", __func__);
      }
  
      return true;
  }
  
  bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig)
  {
      AssertLockHeld(cs_main);
      assert(pindexPrev && pindexPrev == chainActive.Tip());
      if (fCheckpointsEnabled && !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams, block.GetHash()))
          return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__, state.GetRejectReason().c_str());
  
      CCoinsViewCache viewNew(pcoinsTip);
      CBlockIndex indexDummy(block);
      indexDummy.pprev = pindexPrev;
      indexDummy.nHeight = pindexPrev->nHeight + 1;
  
      // NOTE: CheckBlockHeader is called by CheckBlock
      if (!ContextualCheckBlockHeader(block, state, chainparams.GetConsensus(), pindexPrev, GetAdjustedTime()))
          return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, FormatStateMessage(state));
      if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot, fCheckSig))
          return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));
      if (!ContextualCheckBlock(block, state, pindexPrev, !fCheckPOW))
          return error("%s: Consensus::ContextualCheckBlock: %s", __func__, FormatStateMessage(state));
      if (!ConnectBlock(block, state, &indexDummy, viewNew, chainparams, true, !fCheckPOW))
          return false;
      assert(state.IsValid());
  
      return true;
  }
  
  /**
   * BLOCK PRUNING CODE
   */
  
  /* Calculate the amount of disk space the block & undo files currently use */
  uint64_t CalculateCurrentUsage()
  {
      uint64_t retval = 0;
      BOOST_FOREACH(const CBlockFileInfo &file, vinfoBlockFile) {
          retval += file.nSize + file.nUndoSize;
      }
      return retval;
  }
  
  /* Prune a block file (modify associated database entries)*/
  void PruneOneBlockFile(const int fileNumber)
  {
      for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); ++it) {
          CBlockIndex* pindex = it->second;
          if (pindex->nFile == fileNumber) {
              pindex->nStatus &= ~BLOCK_HAVE_DATA;
              pindex->nStatus &= ~BLOCK_HAVE_UNDO;
              pindex->nFile = 0;
              pindex->nDataPos = 0;
              pindex->nUndoPos = 0;
              setDirtyBlockIndex.insert(pindex);
  
              // Prune from mapBlocksUnlinked -- any block we prune would have
              // to be downloaded again in order to consider its chain, at which
              // point it would be considered as a candidate for
              // mapBlocksUnlinked or setBlockIndexCandidates.
              std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex->pprev);
              while (range.first != range.second) {
                  std::multimap<CBlockIndex *, CBlockIndex *>::iterator it = range.first;
                  range.first++;
                  if (it->second == pindex) {
                      mapBlocksUnlinked.erase(it);
                  }
              }
          }
      }
  
      vinfoBlockFile[fileNumber].SetNull();
      setDirtyFileInfo.insert(fileNumber);
  }
  
  
  void UnlinkPrunedFiles(std::set<int>& setFilesToPrune)
  {
      for (set<int>::iterator it = setFilesToPrune.begin(); it != setFilesToPrune.end(); ++it) {
          CDiskBlockPos pos(*it, 0);
          boost::filesystem::remove(GetBlockPosFilename(pos, "blk"));
          boost::filesystem::remove(GetBlockPosFilename(pos, "rev"));
          LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
      }
  }
  
  /* Calculate the block/rev files that should be deleted to remain under target*/
  void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight)
  {
      LOCK2(cs_main, cs_LastBlockFile);
      if (chainActive.Tip() == NULL || nPruneTarget == 0) {
          return;
      }
      if ((uint64_t)chainActive.Tip()->nHeight <= nPruneAfterHeight) {
          return;
      }
  
      unsigned int nLastBlockWeCanPrune = chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP;
      uint64_t nCurrentUsage = CalculateCurrentUsage();
      // We don't check to prune until after we've allocated new space for files
      // So we should leave a buffer under our target to account for another allocation
      // before the next pruning.
      uint64_t nBuffer = BLOCKFILE_CHUNK_SIZE + UNDOFILE_CHUNK_SIZE;
      uint64_t nBytesToPrune;
      int count=0;
  
      if (nCurrentUsage + nBuffer >= nPruneTarget) {
          for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
              nBytesToPrune = vinfoBlockFile[fileNumber].nSize + vinfoBlockFile[fileNumber].nUndoSize;
  
              if (vinfoBlockFile[fileNumber].nSize == 0)
                  continue;
  
              if (nCurrentUsage + nBuffer < nPruneTarget)  // are we below our target?
                  break;
  
              // don't prune files that could have a block within MIN_BLOCKS_TO_KEEP of the main chain's tip but keep scanning
              if (vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
                  continue;
  
              PruneOneBlockFile(fileNumber);
              // Queue up the files for removal
              setFilesToPrune.insert(fileNumber);
              nCurrentUsage -= nBytesToPrune;
              count++;
          }
      }
  
      LogPrint("prune", "Prune: target=%dMiB actual=%dMiB diff=%dMiB max_prune_height=%d removed %d blk/rev pairs\n",
             nPruneTarget/1024/1024, nCurrentUsage/1024/1024,
             ((int64_t)nPruneTarget - (int64_t)nCurrentUsage)/1024/1024,
             nLastBlockWeCanPrune, count);
  }
  
  bool CheckDiskSpace(uint64_t nAdditionalBytes)
  {
      uint64_t nFreeBytesAvailable = boost::filesystem::space(GetDataDir()).available;
  
      // Check for nMinDiskSpace bytes (currently 50MB)
      if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
          return AbortNode("Disk space is low!", _("Error: Disk space is low!"));
  
      return true;
  }
  
  FILE* OpenDiskFile(const CDiskBlockPos &pos, const char *prefix, bool fReadOnly)
  {
      if (pos.IsNull())
          return NULL;
      boost::filesystem::path path = GetBlockPosFilename(pos, prefix);
      boost::filesystem::create_directories(path.parent_path());
      FILE* file = fopen(path.string().c_str(), "rb+");
      if (!file && !fReadOnly)
          file = fopen(path.string().c_str(), "wb+");
      if (!file) {
          LogPrintf("Unable to open file %s\n", path.string());
          return NULL;
      }
      if (pos.nPos) {
          if (fseek(file, pos.nPos, SEEK_SET)) {
              LogPrintf("Unable to seek to position %u of %s\n", pos.nPos, path.string());
              fclose(file);
              return NULL;
          }
      }
      return file;
  }
  
  FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
      return OpenDiskFile(pos, "blk", fReadOnly);
  }
  
  FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
      return OpenDiskFile(pos, "rev", fReadOnly);
  }
  
  boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix)
  {
      return GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
  }
  
  CBlockIndex * InsertBlockIndex(uint256 hash)
  {
      if (hash.IsNull())
          return NULL;
  
      // Return existing
      BlockMap::iterator mi = mapBlockIndex.find(hash);
      if (mi != mapBlockIndex.end())
          return (*mi).second;
  
      // Create new
      CBlockIndex* pindexNew = new CBlockIndex();
      if (!pindexNew)
          throw runtime_error("LoadBlockIndex(): new CBlockIndex failed");
      mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
      pindexNew->phashBlock = &((*mi).first);
  
      return pindexNew;
  }
  
  bool static LoadBlockIndexDB()
  {
      const CChainParams& chainparams = Params();
      if (!pblocktree->LoadBlockIndexGuts(InsertBlockIndex))
          return false;
  
      boost::this_thread::interruption_point();
  
      // Calculate nChainWork
      vector<pair<int, CBlockIndex*> > vSortedByHeight;
      vSortedByHeight.reserve(mapBlockIndex.size());
      BOOST_FOREACH(const PAIRTYPE(uint256, CBlockIndex*)& item, mapBlockIndex)
      {
          CBlockIndex* pindex = item.second;
          vSortedByHeight.push_back(make_pair(pindex->nHeight, pindex));
      }
      sort(vSortedByHeight.begin(), vSortedByHeight.end());
      BOOST_FOREACH(const PAIRTYPE(int, CBlockIndex*)& item, vSortedByHeight)
      {
          CBlockIndex* pindex = item.second;
          pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) + GetBlockProof(*pindex);
          // We can link the chain of blocks for which we've received transactions at some point.
          // Pruned nodes may have deleted the block.
          if (pindex->nTx > 0) {
              if (pindex->pprev) {
                  if (pindex->pprev->nChainTx) {
                      pindex->nChainTx = pindex->pprev->nChainTx + pindex->nTx;
                  } else {
                      pindex->nChainTx = 0;
                      mapBlocksUnlinked.insert(std::make_pair(pindex->pprev, pindex));
                  }
              } else {
                  pindex->nChainTx = pindex->nTx;
              }
          }
          if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->nChainTx || pindex->pprev == NULL))
              setBlockIndexCandidates.insert(pindex);
          if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
              pindexBestInvalid = pindex;
          if (pindex->pprev)
              pindex->BuildSkip();
          if (pindex->IsValid(BLOCK_VALID_TREE) && (pindexBestHeader == NULL || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
              pindexBestHeader = pindex;
      }
  
      // Load block file info
      pblocktree->ReadLastBlockFile(nLastBlockFile);
      vinfoBlockFile.resize(nLastBlockFile + 1);
      LogPrintf("%s: last block file = %i\n", __func__, nLastBlockFile);
      for (int nFile = 0; nFile <= nLastBlockFile; nFile++) {
          pblocktree->ReadBlockFileInfo(nFile, vinfoBlockFile[nFile]);
      }
      LogPrintf("%s: last block file info: %s\n", __func__, vinfoBlockFile[nLastBlockFile].ToString());
      for (int nFile = nLastBlockFile + 1; true; nFile++) {
          CBlockFileInfo info;
          if (pblocktree->ReadBlockFileInfo(nFile, info)) {
              vinfoBlockFile.push_back(info);
          } else {
              break;
          }
      }
  
      // Check presence of blk files
      LogPrintf("Checking all blk files are present...\n");
      set<int> setBlkDataFiles;
      BOOST_FOREACH(const PAIRTYPE(uint256, CBlockIndex*)& item, mapBlockIndex)
      {
          CBlockIndex* pindex = item.second;
          if (pindex->nStatus & BLOCK_HAVE_DATA) {
              setBlkDataFiles.insert(pindex->nFile);
          }
      }
      for (std::set<int>::iterator it = setBlkDataFiles.begin(); it != setBlkDataFiles.end(); it++)
      {
          CDiskBlockPos pos(*it, 0);
          if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION).IsNull()) {
              return false;
          }
      }
  
      // Check whether we have ever pruned block & undo files
      pblocktree->ReadFlag("prunedblockfiles", fHavePruned);
      if (fHavePruned)
          LogPrintf("LoadBlockIndexDB(): Block files have previously been pruned\n");
  
      // Check whether we need to continue reindexing
      bool fReindexing = false;
      pblocktree->ReadReindexing(fReindexing);
      fReindex |= fReindexing;
  
      // Check whether we have a transaction index
      pblocktree->ReadFlag("txindex", fTxIndex);
      LogPrintf("%s: transaction index %s\n", __func__, fTxIndex ? "enabled" : "disabled");
  
      // Check whether we have an address index
      pblocktree->ReadFlag("addressindex", fAddressIndex);
      LogPrintf("%s: address index %s\n", __func__, fAddressIndex ? "enabled" : "disabled");
  
      // Check whether we have a timestamp index
      pblocktree->ReadFlag("timestampindex", fTimestampIndex);
      LogPrintf("%s: timestamp index %s\n", __func__, fTimestampIndex ? "enabled" : "disabled");
  
      // Check whether we have a spent index
      pblocktree->ReadFlag("spentindex", fSpentIndex);
      LogPrintf("%s: spent index %s\n", __func__, fSpentIndex ? "enabled" : "disabled");
  
      // Load pointer to end of best chain
      BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
      if (it == mapBlockIndex.end())
          return true;
      chainActive.SetTip(it->second);
  
      PruneBlockIndexCandidates();
  
      LogPrintf("%s: hashBestChain=%s height=%d date=%s progress=%f\n", __func__,
          chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
          DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
          Checkpoints::GuessVerificationProgress(chainparams.Checkpoints(), chainActive.Tip()));
  
      hashBestChain = chainActive.Tip()->GetBlockHash();
  
      return true;
  }
  
  CVerifyDB::CVerifyDB()
  {
      uiInterface.ShowProgress(_("Verifying blocks..."), 0);
  }
  
  CVerifyDB::~CVerifyDB()
  {
      uiInterface.ShowProgress("", 100);
  }
  
  bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview, int nCheckLevel, int nCheckDepth)
  {
      LOCK(cs_main);
      if (chainActive.Tip() == NULL || chainActive.Tip()->pprev == NULL)
          return true;
  
      // Verify blocks in the best chain
      if (nCheckDepth <= 0)
          nCheckDepth = 1000000000; // suffices until the year 19000
      if (nCheckDepth > chainActive.Height())
          nCheckDepth = chainActive.Height();
      nCheckLevel = std::max(0, std::min(4, nCheckLevel));
      LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
      CCoinsViewCache coins(coinsview);
      CBlockIndex* pindexState = chainActive.Tip();
      CBlockIndex* pindexFailure = NULL;
      int nGoodTransactions = 0;
      CValidationState state;
      int reportDone = 0;
      LogPrintf("[0%]...");
      for (CBlockIndex* pindex = chainActive.Tip(); pindex && pindex->pprev; pindex = pindex->pprev)
      {
          boost::this_thread::interruption_point();
          int percentageDone = std::max(1, std::min(99, (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100))));
          if (reportDone < percentageDone/10) {
              // report every 10% step
              LogPrintf("[%d%%]...", percentageDone);
              reportDone = percentageDone/10;
          }
          uiInterface.ShowProgress(_("Verifying blocks..."), percentageDone);
          if (pindex->nHeight < chainActive.Height()-nCheckDepth)
              break;
          if (fPruneMode && !(pindex->nStatus & BLOCK_HAVE_DATA)) {
              // If pruning, only go back as far as we have data.
              LogPrintf("VerifyDB(): block verification stopping at height %d (pruning, no data)\n", pindex->nHeight);
              break;
          }
          CBlock block;
          // check level 0: read from disk
          if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
              return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
          // check level 1: verify block validity
          if (nCheckLevel >= 1 && !CheckBlock(block, state, chainparams.GetConsensus()))
              return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__,
                           pindex->nHeight, pindex->GetBlockHash().ToString(), FormatStateMessage(state));
          // check level 2: verify undo validity
          if (nCheckLevel >= 2 && pindex) {
              CBlockUndo undo;
              CDiskBlockPos pos = pindex->GetUndoPos();
              if (!pos.IsNull()) {
                  if (!UndoReadFromDisk(undo, pos, pindex->pprev->GetBlockHash()))
                      return error("VerifyDB(): *** found bad undo data at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
              }
          }
          // check level 3: check for inconsistencies during memory-only disconnect of tip blocks
          if (nCheckLevel >= 3 && pindex == pindexState && (coins.DynamicMemoryUsage() + pcoinsTip->DynamicMemoryUsage()) <= nCoinCacheUsage) {
              bool fClean = true;
              if (!DisconnectBlock(block, state, pindex, coins, &fClean))
                  return error("VerifyDB(): *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
              pindexState = pindex->pprev;
              if (!fClean) {
                  nGoodTransactions = 0;
                  pindexFailure = pindex;
              } else
                  nGoodTransactions += block.vtx.size();
          }
          if (ShutdownRequested())
              return true;
      }
      if (pindexFailure)
          return error("VerifyDB(): *** coin database inconsistencies found (last %i blocks, %i good transactions before that)\n", chainActive.Height() - pindexFailure->nHeight + 1, nGoodTransactions);
  
      // check level 4: try reconnecting blocks
      if (nCheckLevel >= 4) {
          CBlockIndex *pindex = pindexState;
          while (pindex != chainActive.Tip()) {
              boost::this_thread::interruption_point();
              uiInterface.ShowProgress(_("Verifying blocks..."), std::max(1, std::min(99, 100 - (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * 50))));
              pindex = chainActive.Next(pindex);
              CBlock block;
              if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
                  return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
              if (!ConnectBlock(block, state, pindex, coins, chainparams))
                  return error("VerifyDB(): *** found unconnectable block at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
          }
      }
  
      LogPrintf("[DONE].\n");
      LogPrintf("No coin database inconsistencies in last %i blocks (%i transactions)\n", chainActive.Height() - pindexState->nHeight, nGoodTransactions);
  
      return true;
  }
  
  bool RewindBlockIndex(const CChainParams& params)
  {
      LOCK(cs_main);
  
      int nHeight = 1;
      while (nHeight <= chainActive.Height()) {
          if (IsWitnessEnabled(chainActive[nHeight - 1], params.GetConsensus()) && !(chainActive[nHeight]->nStatus & BLOCK_OPT_WITNESS)) {
              break;
          }
          nHeight++;
      }
  
      // nHeight is now the height of the first insufficiently-validated block, or tipheight + 1
      CValidationState state;
      CBlockIndex* pindex = chainActive.Tip();
      while (chainActive.Height() >= nHeight) {
          if (fPruneMode && !(chainActive.Tip()->nStatus & BLOCK_HAVE_DATA)) {
              // If pruning, don't try rewinding past the HAVE_DATA point;
              // since older blocks can't be served anyway, there's
              // no need to walk further, and trying to DisconnectTip()
              // will fail (and require a needless reindex/redownload
              // of the blockchain).
              break;
          }
          if (!DisconnectTip(state, params, true)) {
              return error("RewindBlockIndex: unable to disconnect block at height %i", pindex->nHeight);
          }
          // Occasionally flush state to disk.
          if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC))
              return false;
      }
  
      // Reduce validity flag and have-data flags.
      // We do this after actual disconnecting, otherwise we'll end up writing the lack of data
      // to disk before writing the chainstate, resulting in a failure to continue if interrupted.
      for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
          CBlockIndex* pindexIter = it->second;
  
          // Note: If we encounter an insufficiently validated block that
          // is on chainActive, it must be because we are a pruning node, and
          // this block or some successor doesn't HAVE_DATA, so we were unable to
          // rewind all the way.  Blocks remaining on chainActive at this point
          // must not have their validity reduced.
          if (IsWitnessEnabled(pindexIter->pprev, params.GetConsensus()) && !(pindexIter->nStatus & BLOCK_OPT_WITNESS) && !chainActive.Contains(pindexIter)) {
              // Reduce validity
              pindexIter->nStatus = std::min<unsigned int>(pindexIter->nStatus & BLOCK_VALID_MASK, BLOCK_VALID_TREE) | (pindexIter->nStatus & ~BLOCK_VALID_MASK);
              // Remove have-data flags.
              pindexIter->nStatus &= ~(BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO);
              // Remove storage location.
              pindexIter->nFile = 0;
              pindexIter->nDataPos = 0;
              pindexIter->nUndoPos = 0;
              // Remove various other things
              pindexIter->nTx = 0;
              pindexIter->nChainTx = 0;
              pindexIter->nSequenceId = 0;
              // Make sure it gets written.
              setDirtyBlockIndex.insert(pindexIter);
              // Update indexes
              setBlockIndexCandidates.erase(pindexIter);
              std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> ret = mapBlocksUnlinked.equal_range(pindexIter->pprev);
              while (ret.first != ret.second) {
                  if (ret.first->second == pindexIter) {
                      mapBlocksUnlinked.erase(ret.first++);
                  } else {
                      ++ret.first;
                  }
              }
          } else if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) && pindexIter->nChainTx) {
              setBlockIndexCandidates.insert(pindexIter);
          }
      }
  
      PruneBlockIndexCandidates();
  
      CheckBlockIndex(params.GetConsensus());
  
      if (!FlushStateToDisk(state, FLUSH_STATE_ALWAYS)) {
          return false;
      }
  
      return true;
  }
  
  void UnloadBlockIndex()
  {
      LOCK(cs_main);
      setBlockIndexCandidates.clear();
      chainActive.SetTip(NULL);
      pindexBestInvalid = NULL;
      pindexBestHeader = NULL;
      mempool.clear();
      mapOrphanTransactions.clear();
      mapOrphanTransactionsByPrev.clear();
      nSyncStarted = 0;
      mapBlocksUnlinked.clear();
      vinfoBlockFile.clear();
      nLastBlockFile = 0;
      nBlockSequenceId = 1;
      mapBlockSource.clear();
      mapBlocksInFlight.clear();
      nPreferredDownload = 0;
      setDirtyBlockIndex.clear();
      setDirtyFileInfo.clear();
      mapNodeState.clear();
      recentRejects.reset(NULL);
      versionbitscache.Clear();
      for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
          warningcache[b].clear();
      }
  
      BOOST_FOREACH(BlockMap::value_type& entry, mapBlockIndex) {
          delete entry.second;
      }
      mapBlockIndex.clear();
      fHavePruned = false;
  }
  
  bool LoadBlockIndex()
  {
      // Load block index from databases
      if (!fReindex && !LoadBlockIndexDB())
          return false;
      return true;
  }
  
  bool InitBlockIndex(const CChainParams& chainparams)
  {
      LOCK(cs_main);
  
      // Initialize global variables that cannot be constructed at startup.
      recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
  
      // Check whether we're already initialized
      if (chainActive.Genesis() != NULL)
          return true;
  
      // Use the provided setting for -txindex in the new database
      fTxIndex = GetBoolArg("-txindex", DEFAULT_TXINDEX);
      pblocktree->WriteFlag("txindex", fTxIndex);
      LogPrintf("%s: transaction index %s\n", __func__, fTxIndex ? "enabled" : "disabled");
  
      // Use the provided setting for -addressindex in the new database
      fAddressIndex = GetBoolArg("-addressindex", DEFAULT_ADDRESSINDEX);
      pblocktree->WriteFlag("addressindex", fAddressIndex);
      LogPrintf("%s: address index %s\n", __func__, fAddressIndex ? "enabled" : "disabled");
  
      // Use the provided setting for -timestampindex in the new database
      fTimestampIndex = GetBoolArg("-timestampindex", DEFAULT_TIMESTAMPINDEX);
      pblocktree->WriteFlag("timestampindex", fTimestampIndex);
      LogPrintf("%s: timestamp index %s\n", __func__, fTimestampIndex ? "enabled" : "disabled");
  
      // Use the provided setting for -spentindex in the new database
      fSpentIndex = GetBoolArg("-spentindex", DEFAULT_SPENTINDEX);
      pblocktree->WriteFlag("spentindex", fSpentIndex);
      LogPrintf("%s: spent index %s\n", __func__, fSpentIndex ? "enabled" : "disabled");
  
      LogPrintf("Initializing databases...\n");
  
      // Only add the genesis block if not reindexing (in which case we reuse the one already on disk)
      if (!fReindex) {
          try {
              CBlock &block = const_cast<CBlock&>(chainparams.GenesisBlock());
              // Start new block file
              unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
              CDiskBlockPos blockPos;
              CValidationState state;
              if (!FindBlockPos(state, blockPos, nBlockSize+8, 0, block.GetBlockTime()))
                  return error("LoadBlockIndex(): FindBlockPos failed");
              if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
                  return error("LoadBlockIndex(): writing genesis block to disk failed");
              CBlockIndex *pindex = AddToBlockIndex(block);
              if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
                  return error("LoadBlockIndex(): genesis block not accepted");
              if (!ActivateBestChain(state, chainparams, &block))
                  return error("LoadBlockIndex(): genesis block cannot be activated");
              // Force a chainstate write so that when we VerifyDB in a moment, it doesn't check stale data
              return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
          } catch (const std::runtime_error& e) {
              return error("LoadBlockIndex(): failed to initialize block database: %s", e.what());
          }
      }
  
      return true;
  }
  
  bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos *dbp)
  {
      // Map of disk positions for blocks with unknown parent (only used for reindex)
      static std::multimap<uint256, CDiskBlockPos> mapBlocksUnknownParent;
      int64_t nStart = GetTimeMillis();
  
      int nLoaded = 0;
      try {
          // This takes over fileIn and calls fclose() on it in the CBufferedFile destructor
          CBufferedFile blkdat(fileIn, 2*MAX_BLOCK_SERIALIZED_SIZE, MAX_BLOCK_SERIALIZED_SIZE+8, SER_DISK, CLIENT_VERSION);
          uint64_t nRewind = blkdat.GetPos();
          while (!blkdat.eof()) {
              boost::this_thread::interruption_point();
  
              blkdat.SetPos(nRewind);
              nRewind++; // start one byte further next time, in case of failure
              blkdat.SetLimit(); // remove former limit
              unsigned int nSize = 0;
              try {
                  // locate a header
                  unsigned char buf[MESSAGE_START_SIZE];
                  blkdat.FindByte(chainparams.MessageStart()[0]);
                  nRewind = blkdat.GetPos()+1;
                  blkdat >> FLATDATA(buf);
                  if (memcmp(buf, chainparams.MessageStart(), MESSAGE_START_SIZE))
                      continue;
                  // read size
                  blkdat >> nSize;
                  if (nSize < 80 || nSize > MAX_BLOCK_SERIALIZED_SIZE)
                      continue;
              } catch (const std::exception&) {
                  // no valid block header found; don't complain
                  break;
              }
              try {
                  // read block
                  uint64_t nBlockPos = blkdat.GetPos();
                  if (dbp)
                      dbp->nPos = nBlockPos;
                  blkdat.SetLimit(nBlockPos + nSize);
                  blkdat.SetPos(nBlockPos);
                  CBlock block;
                  blkdat >> block;
                  nRewind = blkdat.GetPos();
  
                  // detect out of order blocks, and store them for later
                  uint256 hash = block.GetHash();
                  if (hash != chainparams.GetConsensus().hashGenesisBlock && mapBlockIndex.find(block.hashPrevBlock) == mapBlockIndex.end()) {
                      LogPrint("reindex", "%s: Out of order block %s, parent %s not known\n", __func__, hash.ToString(),
                              block.hashPrevBlock.ToString());
                      if (dbp)
                          mapBlocksUnknownParent.insert(std::make_pair(block.hashPrevBlock, *dbp));
                      continue;
                  }
  
                  // process in case the block isn't known yet
                  if (mapBlockIndex.count(hash) == 0 || (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
                      LOCK(cs_main);
                      CValidationState state;
                      if (AcceptBlock(block, state, chainparams, NULL, true, dbp, NULL))
                          nLoaded++;
                      if (state.IsError())
                          break;
                  } else if (hash != chainparams.GetConsensus().hashGenesisBlock && mapBlockIndex[hash]->nHeight % 1000 == 0) {
                      LogPrint("reindex", "Block Import: already had block %s at height %d\n", hash.ToString(), mapBlockIndex[hash]->nHeight);
                  }
  
                  // Activate the genesis block so normal node progress can continue
                  if (hash == chainparams.GetConsensus().hashGenesisBlock) {
                      CValidationState state;
                      if (!ActivateBestChain(state, chainparams)) {
                          break;
                      }
                  }
  
                  NotifyHeaderTip();
  
                  // Recursively process earlier encountered successors of this block
                  deque<uint256> queue;
                  queue.push_back(hash);
                  while (!queue.empty()) {
                      uint256 head = queue.front();
                      queue.pop_front();
                      std::pair<std::multimap<uint256, CDiskBlockPos>::iterator, std::multimap<uint256, CDiskBlockPos>::iterator> range = mapBlocksUnknownParent.equal_range(head);
                      while (range.first != range.second) {
                          std::multimap<uint256, CDiskBlockPos>::iterator it = range.first;
                          if (ReadBlockFromDisk(block, it->second, chainparams.GetConsensus()))
                          {
                              LogPrint("reindex", "%s: Processing out of order child %s of %s\n", __func__, block.GetHash().ToString(),
                                      head.ToString());
                              LOCK(cs_main);
                              CValidationState dummy;
  
                              if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second, NULL))
                              {
                                  nLoaded++;
                                  queue.push_back(block.GetHash());
                              }
                          }
                          range.first++;
                          mapBlocksUnknownParent.erase(it);
                          NotifyHeaderTip();
                      }
                  }
              } catch (const std::exception& e) {
                  LogPrintf("%s: Deserialize or I/O error - %s\n", __func__, e.what());
              }
          }
      } catch (const std::runtime_error& e) {
          AbortNode(std::string("System error: ") + e.what());
      }
      if (nLoaded > 0)
          LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
      return nLoaded > 0;
  }
  
  void static CheckBlockIndex(const Consensus::Params& consensusParams)
  {
      if (!fCheckBlockIndex) {
          return;
      }
  
      LOCK(cs_main);
  
      // During a reindex, we read the genesis block and call CheckBlockIndex before ActivateBestChain,
      // so we have the genesis block in mapBlockIndex but no active chain.  (A few of the tests when
      // iterating the block tree require that chainActive has been initialized.)
      if (chainActive.Height() < 0) {
          assert(mapBlockIndex.size() <= 1);
          return;
      }
  
      // Build forward-pointing map of the entire block tree.
      std::multimap<CBlockIndex*,CBlockIndex*> forward;
      for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
          forward.insert(std::make_pair(it->second->pprev, it->second));
      }
  
      assert(forward.size() == mapBlockIndex.size());
  
      std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(NULL);
      CBlockIndex *pindex = rangeGenesis.first->second;
      rangeGenesis.first++;
      assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent NULL.
  
      // Iterate over the entire block tree, using depth-first search.
      // Along the way, remember whether there are blocks on the path from genesis
      // block being explored which are the first to have certain properties.
      size_t nNodes = 0;
      int nHeight = 0;
      CBlockIndex* pindexFirstInvalid = NULL; // Oldest ancestor of pindex which is invalid.
      CBlockIndex* pindexFirstMissing = NULL; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
      CBlockIndex* pindexFirstNeverProcessed = NULL; // Oldest ancestor of pindex for which nTx == 0.
      CBlockIndex* pindexFirstNotTreeValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not).
      CBlockIndex* pindexFirstNotTransactionsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not).
      CBlockIndex* pindexFirstNotChainValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not).
      CBlockIndex* pindexFirstNotScriptsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not).
      CBlockIndex* pindexFirstNotStakeValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_STAKE (regardless of being valid or not).
      while (pindex != NULL) {
          nNodes++;
          if (pindexFirstInvalid == NULL && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
          if (pindexFirstMissing == NULL && !(pindex->nStatus & BLOCK_HAVE_DATA)) pindexFirstMissing = pindex;
          if (pindexFirstNeverProcessed == NULL && pindex->nTx == 0) pindexFirstNeverProcessed = pindex;
          if (pindex->pprev != NULL && pindexFirstNotTreeValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex;
          if (pindex->pprev != NULL && pindexFirstNotTransactionsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) pindexFirstNotTransactionsValid = pindex;
          if (pindex->pprev != NULL && pindexFirstNotChainValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) pindexFirstNotChainValid = pindex;
          if (pindex->pprev != NULL && pindexFirstNotStakeValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_STAKE) pindexFirstNotStakeValid = pindex;
          if (pindex->pprev != NULL && pindexFirstNotScriptsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) pindexFirstNotScriptsValid = pindex;
  
          // Begin: actual consistency checks.
          if (pindex->pprev == NULL) {
              // Genesis block checks.
              assert(pindex->GetBlockHash() == consensusParams.hashGenesisBlock); // Genesis block's hash must match.
              assert(pindex == chainActive.Genesis()); // The current active chain's genesis block must be this block.
          }
          if (pindex->nChainTx == 0) assert(pindex->nSequenceId == 0);  // nSequenceId can't be set for blocks that aren't linked
          // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred).
          // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred.
          if (!fHavePruned) {
              // If we've never pruned, then HAVE_DATA should be equivalent to nTx > 0
              assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0));
              assert(pindexFirstMissing == pindexFirstNeverProcessed);
          } else {
              // If we have pruned, then we can only say that HAVE_DATA implies nTx > 0
              if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0);
          }
          if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA);
          assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent.
          // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to nChainTx being set.
          assert((pindexFirstNeverProcessed != NULL) == (pindex->nChainTx == 0)); // nChainTx != 0 is used to signal that all parent blocks have been processed (but may have been pruned).
          assert((pindexFirstNotTransactionsValid != NULL) == (pindex->nChainTx == 0));
          assert(pindex->nHeight == nHeight); // nHeight must be consistent.
          assert(pindex->pprev == NULL || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's.
          assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks.
          assert(pindexFirstNotTreeValid == NULL); // All mapBlockIndex entries must at least be TREE valid
          if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == NULL); // TREE valid implies all parents are TREE valid
          if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == NULL); // CHAIN valid implies all parents are CHAIN valid
          if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_STAKE) assert(pindexFirstNotStakeValid == NULL); // STAKE valid implies all parents are STAKE valid
          if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == NULL); // SCRIPTS valid implies all parents are SCRIPTS valid
          if (pindexFirstInvalid == NULL) {
              // Checks for not-invalid blocks.
              assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
          }
          if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && pindexFirstNeverProcessed == NULL) {
              if (pindexFirstInvalid == NULL) {
                  // If this block sorts at least as good as the current tip and
                  // is valid and we have all data for its parents, it must be in
                  // setBlockIndexCandidates.  chainActive.Tip() must also be there
                  // even if some data has been pruned.
                  if (pindexFirstMissing == NULL || pindex == chainActive.Tip()) {
                      assert(setBlockIndexCandidates.count(pindex));
                  }
                  // If some parent is missing, then it could be that this block was in
                  // setBlockIndexCandidates but had to be removed because of the missing data.
                  // In this case it must be in mapBlocksUnlinked -- see test below.
              }
          } else { // If this block sorts worse than the current tip or some ancestor's block has never been seen, it cannot be in setBlockIndexCandidates.
              assert(setBlockIndexCandidates.count(pindex) == 0);
          }
          // Check whether this block is in mapBlocksUnlinked.
          std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeUnlinked = mapBlocksUnlinked.equal_range(pindex->pprev);
          bool foundInUnlinked = false;
          while (rangeUnlinked.first != rangeUnlinked.second) {
              assert(rangeUnlinked.first->first == pindex->pprev);
              if (rangeUnlinked.first->second == pindex) {
                  foundInUnlinked = true;
                  break;
              }
              rangeUnlinked.first++;
          }
          if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != NULL && pindexFirstInvalid == NULL) {
              // If this block has block data available, some parent was never received, and has no invalid parents, it must be in mapBlocksUnlinked.
              assert(foundInUnlinked);
          }
          if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); // Can't be in mapBlocksUnlinked if we don't HAVE_DATA
          if (pindexFirstMissing == NULL) assert(!foundInUnlinked); // We aren't missing data for any parent -- cannot be in mapBlocksUnlinked.
          if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == NULL && pindexFirstMissing != NULL) {
              // We HAVE_DATA for this block, have received data for all parents at some point, but we're currently missing data for some parent.
              assert(fHavePruned); // We must have pruned.
              // This block may have entered mapBlocksUnlinked if:
              //  - it has a descendant that at some point had more work than the
              //    tip, and
              //  - we tried switching to that descendant but were missing
              //    data for some intermediate block between chainActive and the
              //    tip.
              // So if this block is itself better than chainActive.Tip() and it wasn't in
              // setBlockIndexCandidates, then it must be in mapBlocksUnlinked.
              if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && setBlockIndexCandidates.count(pindex) == 0) {
                  if (pindexFirstInvalid == NULL) {
                      assert(foundInUnlinked);
                  }
              }
          }
          // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash()); // Perhaps too slow
          // End: actual consistency checks.
  
          // Try descending into the first subnode.
          std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> range = forward.equal_range(pindex);
          if (range.first != range.second) {
              // A subnode was found.
              pindex = range.first->second;
              nHeight++;
              continue;
          }
          // This is a leaf node.
          // Move upwards until we reach a node of which we have not yet visited the last child.
          while (pindex) {
              // We are going to either move to a parent or a sibling of pindex.
              // If pindex was the first with a certain property, unset the corresponding variable.
              if (pindex == pindexFirstInvalid) pindexFirstInvalid = NULL;
              if (pindex == pindexFirstMissing) pindexFirstMissing = NULL;
              if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = NULL;
              if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = NULL;
              if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = NULL;
              if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = NULL;
              if (pindex == pindexFirstNotStakeValid) pindexFirstNotStakeValid = NULL;
              if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = NULL;
              // Find our parent.
              CBlockIndex* pindexPar = pindex->pprev;
              // Find which child we just visited.
              std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangePar = forward.equal_range(pindexPar);
              while (rangePar.first->second != pindex) {
                  assert(rangePar.first != rangePar.second); // Our parent must have at least the node we're coming from as child.
                  rangePar.first++;
              }
              // Proceed to the next one.
              rangePar.first++;
              if (rangePar.first != rangePar.second) {
                  // Move to the sibling.
                  pindex = rangePar.first->second;
                  break;
              } else {
                  // Move up further.
                  pindex = pindexPar;
                  nHeight--;
                  continue;
              }
          }
      }
  
      // Check that we actually traversed the entire map.
      assert(nNodes == forward.size());
  }
  
  std::string GetWarnings(const std::string& strFor)
  {
      return GetWarnings(strFor, false);
  }
  
  std::string GetWarnings(const std::string& strFor, bool fForStaking)
  {
      string strStatusBar;
      string strRPC;
      string strGUI;
  
      if (!CLIENT_VERSION_IS_RELEASE)
      {
          strStatusBar = "This is a pre-release Test build - use at your own risk - please make sure your wallet is backed up";
          strGUI = _("This is a pre-release Test build - use at your own risk - please make sure your wallet is backed up");
  
          if(CLIENT_BUILD_IS_RELEASE_CANDIDATE)
          {
              strStatusBar = "This is a Release Candidate build - use at your own risk - please make sure your wallet is backed up";
              strGUI = _("This is a Release Candidate build - use at your own risk - please make sure your wallet is backed up");
          }
      }
  
      if (GetBoolArg("-testsafemode", DEFAULT_TESTSAFEMODE))
          strStatusBar = strRPC = strGUI = "testsafemode enabled";
  
      // Misc warnings like out of disk space and clock is wrong
      if (strMiscWarning != "")
      {
          strStatusBar = strGUI = strMiscWarning;
      }
  
      if (fLargeWorkForkFound)
      {
          strStatusBar = strRPC = "Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.";
          strGUI = _(strRPC.c_str());
      }
      else if (fLargeWorkInvalidChainFound)
      {
          strStatusBar = strRPC = "Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.";
          strGUI = _(strRPC.c_str());
      }
  
      if (fForStaking)
      {
          if (pwalletMain->IsLocked())
          {
              strStatusBar = strRPC = "Warning: Wallet is locked. Please enter the wallet passphrase with walletpassphrase first.";
              strGUI = _(strRPC.c_str());
          }
  
          if (!pwalletMain->GetStakeWeight())
          {
              strStatusBar = strRPC = "Warning: We don't appear to have mature coins.";
              strGUI = _(strRPC.c_str());
          }
      }
  
      if (strFor == "gui")
          return strGUI;
  
      if (strFor == "statusbar")
          return strStatusBar;
  
      if (strFor == "rpc")
          return strRPC;
  
      assert(!"GetWarnings(): invalid parameter");
      return "error";
  }
  
  
  
  
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // Messages
  //
  
  
  bool static AlreadyHave(const CInv& inv) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
  {
      switch (inv.type)
      {
      case MSG_TX:
      case MSG_WITNESS_TX:
          {
              assert(recentRejects);
              if (chainActive.Tip()->GetBlockHash() != hashRecentRejectsChainTip)
              {
                  // If the chain tip has changed previously rejected transactions
                  // might be now valid, e.g. due to a nLockTime'd tx becoming valid,
                  // or a double-spend. Reset the rejects filter and give those
                  // txs a second chance.
                  hashRecentRejectsChainTip = chainActive.Tip()->GetBlockHash();
                  recentRejects->reset();
              }
  
              // Use pcoinsTip->HaveCoinsInCache as a quick approximation to exclude
              // requesting or processing some txs which have already been included in a block
              return recentRejects->contains(inv.hash) ||
                     mempool.exists(inv.hash) ||
                     mapOrphanTransactions.count(inv.hash) ||
                     pcoinsTip->HaveCoinsInCache(inv.hash);
          }
      case MSG_BLOCK:
      case MSG_WITNESS_BLOCK:
          return mapBlockIndex.count(inv.hash);
      }
      // Don't know what it is, just say we already got one
      return true;
  }
  
  void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParams)
  {
      std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
  
      vector<CInv> vNotFound;
  
      LOCK(cs_main);
  
      while (it != pfrom->vRecvGetData.end()) {
          // Don't bother if send buffer is too full to respond anyway
          if (pfrom->nSendSize >= SendBufferSize())
              break;
  
          const CInv &inv = *it;
          {
              boost::this_thread::interruption_point();
              it++;
  
              if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK)
              {
                  bool send = false;
                  BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
                  if (mi != mapBlockIndex.end())
                  {
                      if (chainActive.Contains(mi->second)) {
                          send = true;
                      } else {
                          static const int nOneMonth = 30 * 24 * 60 * 60;
                          // To prevent fingerprinting attacks, only send blocks outside of the active
                          // chain if they are valid, and no more than a month older (both in time, and in
                          // best equivalent proof of work) than the best header chain we know about.
                          send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != NULL) &&
                              (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() < nOneMonth) &&
                              (GetBlockProofEquivalentTime(*pindexBestHeader, *mi->second, *pindexBestHeader, consensusParams) < nOneMonth);
                          if (!send) {
                              LogPrintf("%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId());
                          }
                      }
                  }
                  // disconnect node in case we have reached the outbound limit for serving historical blocks
                  // never disconnect whitelisted nodes
                  static const int nOneWeek = 7 * 24 * 60 * 60; // assume > 1 week = historical
                  if (send && CNode::OutboundTargetReached(true) && ( ((pindexBestHeader != NULL) && (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() > nOneWeek)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted)
                  {
                      LogPrint("net", "historical block serving limit reached, disconnect peer=%d\n", pfrom->GetId());
  
                      //disconnect node
                      pfrom->fDisconnect = true;
                      send = false;
                  }
                  // Pruned nodes may have deleted the block, so check whether
                  // it's available before trying to send.
                  if (send && (mi->second->nStatus & BLOCK_HAVE_DATA))
                  {
                      // Send block from disk
                      CBlock block;
                      if (!ReadBlockFromDisk(block, (*mi).second, consensusParams))
                          assert(!"cannot load block from disk");
                      if (inv.type == MSG_BLOCK)
                          pfrom->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, block);
                      else if (inv.type == MSG_WITNESS_BLOCK)
                          pfrom->PushMessage(NetMsgType::BLOCK, block);
                      else if (inv.type == MSG_FILTERED_BLOCK)
                      {
                          LOCK(pfrom->cs_filter);
                          if (pfrom->pfilter)
                          {
                              CMerkleBlock merkleBlock(block, *pfrom->pfilter);
                              pfrom->PushMessage(NetMsgType::MERKLEBLOCK, merkleBlock);
                              // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see
                              // This avoids hurting performance by pointlessly requiring a round-trip
                              // Note that there is currently no way for a node to request any single transactions we didn't send here -
                              // they must either disconnect and retry or request the full block.
                              // Thus, the protocol spec specified allows for us to provide duplicate txn here,
                              // however we MUST always provide at least what the remote peer needs
                              typedef std::pair<unsigned int, uint256> PairType;
                              BOOST_FOREACH(PairType& pair, merkleBlock.vMatchedTxn)
                                  pfrom->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::TX, block.vtx[pair.first]);
                          }
                          // else
                              // no response
                      }
                      else if (inv.type == MSG_CMPCT_BLOCK)
                      {
                          // If a peer is asking for old blocks, we're almost guaranteed
                          // they wont have a useful mempool to match against a compact block,
                          // and we dont feel like constructing the object for them, so
                          // instead we respond with the full, non-compact block.
  //                        if (mi->second->nHeight >= chainActive.Height() - 10) {
  //                            CBlockHeaderAndShortTxIDs cmpctblock(block);
  //                            pfrom->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::CMPCTBLOCK, cmpctblock);
  //                        } else
                              pfrom->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, block);
                      }
  
                      // Trigger the peer node to send a getblocks request for the next batch of inventory
                      if (inv.hash == pfrom->hashContinue)
                      {
                          // Bypass PushInventory, this must send even if redundant,
                          // and we want it right after the last block so they don't
                          // wait for other stuff first.
                          vector<CInv> vInv;
                          vInv.push_back(CInv(MSG_BLOCK, chainActive.Tip()->GetBlockHash()));
                          pfrom->PushMessage(NetMsgType::INV, vInv);
                          pfrom->hashContinue.SetNull();
                      }
                  }
              }
              else if (inv.type == MSG_TX || inv.type == MSG_WITNESS_TX)
              {
                  // Send stream from relay memory
                  bool push = false;
                  auto mi = mapRelay.find(inv.hash);
                  if (mi != mapRelay.end()) {
                      pfrom->PushMessageWithFlag(inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0, NetMsgType::TX, *mi->second);
                      push = true;
                  } else if (pfrom->timeLastMempoolReq) {
                      auto txinfo = mempool.info(inv.hash);
                      // To protect privacy, do not answer getdata using the mempool when
                      // that TX couldn't have been INVed in reply to a MEMPOOL request.
                      if (txinfo.tx && txinfo.nTime <= pfrom->timeLastMempoolReq) {
                          pfrom->PushMessageWithFlag(inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0, NetMsgType::TX, *txinfo.tx);
                          push = true;
                      }
                  }
                  if (!push) {
                      vNotFound.push_back(inv);
                  }
              }
  
              // Track requests for our stuff.
              GetMainSignals().Inventory(inv.hash);
  
              if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK)
                  break;
          }
      }
  
      pfrom->vRecvGetData.erase(pfrom->vRecvGetData.begin(), it);
  
      if (!vNotFound.empty()) {
          // Let the peer know that we didn't find what it asked for, so it doesn't
          // have to wait around forever. Currently only SPV clients actually care
          // about this message: it's needed when they are recursively walking the
          // dependencies of relevant unconfirmed transactions. SPV clients want to
          // do that because they want to know about (and store and rebroadcast and
          // risk analyze) the dependencies of transactions relevant to them, without
          // having to download the entire memory pool.
          pfrom->PushMessage(NetMsgType::NOTFOUND, vNotFound);
      }
  }
  
  uint32_t GetFetchFlags(CNode* pfrom, CBlockIndex* pprev, const Consensus::Params& chainparams) {
      uint32_t nFetchFlags = 0;
      if (IsWitnessEnabled(pprev, chainparams) && State(pfrom->GetId())->fHaveWitness) {
          nFetchFlags |= MSG_WITNESS_FLAG;
      }
      return nFetchFlags;
  }
  
  bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived, const CChainParams& chainparams)
  {
      LogPrint("net", "received: %s (%u bytes) peer=%d\n", SanitizeString(strCommand), vRecv.size(), pfrom->id);
  
      if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
      {
          LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");
          return true;
      }
  
  
      if (!(nLocalServices & NODE_BLOOM) &&
                (strCommand == NetMsgType::FILTERLOAD ||
                 strCommand == NetMsgType::FILTERADD ||
                 strCommand == NetMsgType::FILTERCLEAR))
      {
          if (pfrom->nVersion >= NO_BLOOM_VERSION) {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 100);
              return false;
          } else {
              pfrom->fDisconnect = true;
              return false;
          }
      }
  
      if (pfrom->nVersion != 0)
      {
          bool fObsolete = false;
          string reason = "";
  
          if(pfrom->nVersion < 70015)
          {
              reason = "You are using an old version of NavCoin, please update.";
              fObsolete = true;
          }
  
          if(pfrom->nVersion < 70017 && IsWitnessEnabled(chainActive.Tip(), Params().GetConsensus()))
          {
              reason = "Segregated Witness has been enabled and you are using an old version of NavCoin, please update.";
              fObsolete = true;
          }
  
          if(pfrom->nVersion < 70020 && IsCommunityFundEnabled(chainActive.Tip(), Params().GetConsensus()))
          {
              reason = "Community Fund has been enabled and you are using an old version of NavCoin, please update.";
              fObsolete = true;
          }
  
          if(fObsolete)
          {
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE, reason);
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 100);
              return false;
          }
      }
  
  
      if (strCommand == NetMsgType::VERSION)
      {
          // Each connection can only send one version message
          if (pfrom->nVersion != 0)
          {
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_DUPLICATE, string("Duplicate version message"));
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 1);
              return false;
          }
  
          int64_t nTime;
          CAddress addrMe;
          CAddress addrFrom;
          uint64_t nNonce = 1;
          uint64_t nServiceInt;
          vRecv >> pfrom->nVersion >> nServiceInt >> nTime >> addrMe;
  
          pfrom->nServices = ServiceFlags(nServiceInt);
          if (!pfrom->fInbound)
          {
              addrman.SetServices(pfrom->addr, pfrom->nServices);
          }
          if (pfrom->nServicesExpected & ~pfrom->nServices)
          {
              LogPrint("net", "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom->id, pfrom->nServices, pfrom->nServicesExpected);
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD,
                                 strprintf("Expected to offer services %08x", pfrom->nServicesExpected));
              pfrom->fDisconnect = true;
              return false;
          }
  
          if (pfrom->nVersion < MIN_PEER_PROTO_VERSION)
          {
              // disconnect from peers older than this proto version
              LogPrintf("peer=%d using obsolete version %i; disconnecting\n", pfrom->id, pfrom->nVersion);
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
                                 strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION));
              pfrom->fDisconnect = true;
              return false;
          }
  
          if (pfrom->nVersion == 10300)
              pfrom->nVersion = 300;
          if (!vRecv.empty())
              vRecv >> addrFrom >> nNonce;
          if (!vRecv.empty()) {
              vRecv >> LIMITED_STRING(pfrom->strSubVer, MAX_SUBVERSION_LENGTH);
              pfrom->cleanSubVer = SanitizeString(pfrom->strSubVer);
          }
          if (!vRecv.empty()) {
              vRecv >> pfrom->nStartingHeight;
          }
          {
              LOCK(pfrom->cs_filter);
              if (!vRecv.empty())
                  vRecv >> pfrom->fRelayTxes; // set to true after we get the first filter* message
              else
                  pfrom->fRelayTxes = true;
          }
  
          // Disconnect if we connected to ourself
          if (nNonce == nLocalHostNonce && nNonce > 1)
          {
              LogPrintf("connected to self at %s, disconnecting\n", pfrom->addr.ToString());
              pfrom->fDisconnect = true;
              return true;
          }
  
          pfrom->addrLocal = addrMe;
          if (pfrom->fInbound && addrMe.IsRoutable())
          {
              SeenLocal(addrMe);
          }
  
          // Be shy and don't send version until we hear
          if (pfrom->fInbound)
              pfrom->PushVersion();
  
          pfrom->fClient = !(pfrom->nServices & NODE_NETWORK);
  
          if((pfrom->nServices & NODE_WITNESS))
          {
              LOCK(cs_main);
              State(pfrom->GetId())->fHaveWitness = true;
          }
  
          // Potentially mark this peer as a preferred download peer.
          {
          LOCK(cs_main);
          UpdatePreferredDownload(pfrom, State(pfrom->GetId()));
          }
  
          // Change version
          pfrom->PushMessage(NetMsgType::VERACK);
          pfrom->ssSend.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
  
          if (!pfrom->fInbound)
          {
              // Advertise our address
              if (fListen && !IsInitialBlockDownload())
              {
                  CAddress addr = GetLocalAddress(&pfrom->addr);
                  if (addr.IsRoutable())
                  {
                      LogPrintf("ProcessMessages: advertising address %s\n", addr.ToString());
                      pfrom->PushAddress(addr);
                  } else if (IsPeerAddrLocalGood(pfrom)) {
                      addr.SetIP(pfrom->addrLocal);
                      LogPrintf("ProcessMessages: advertising address %s\n", addr.ToString());
                      pfrom->PushAddress(addr);
                  }
              }
  
              // Get recent addresses
              if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
              {
                  pfrom->PushMessage(NetMsgType::GETADDR);
                  pfrom->fGetAddr = true;
              }
              addrman.Good(pfrom->addr);
          } else {
              if (((CNetAddr)pfrom->addr) == (CNetAddr)addrFrom)
              {
                  addrman.Add(addrFrom, addrFrom);
                  addrman.Good(addrFrom);
              }
          }
  
          string remoteAddr;
          if (fLogIPs)
              remoteAddr = ", peeraddr=" + pfrom->addr.ToString();
  
          LogPrintf("receive version message: %s: version %d, blocks=%d, us=%s, peer=%d%s\n",
                    pfrom->cleanSubVer, pfrom->nVersion,
                    pfrom->nStartingHeight, addrMe.ToString(), pfrom->id,
                    remoteAddr);
  
          if (mapMultiArgs.count("-banversion") > 0)
          {
              std::vector<std::string> vBannedVersions = mapMultiArgs["-banversion"];
              bool fBanned = false;
  
              for (unsigned int i = 0; i < vBannedVersions.size(); i++)
              {
                  if(vBannedVersions[i] == pfrom->cleanSubVer)
                  {
                      fBanned = true;
                      break;
                  }
              }
  
              if(fBanned)
              {
                  LOCK(cs_main);
                  Misbehaving(pfrom->GetId(), 100);
                  return false;
              }
          }
  
          int64_t nTimeOffset = nTime - GetTime();
          pfrom->nTimeOffset = nTimeOffset;
          if(IsNtpSyncEnabled(chainActive.Tip(), Params().GetConsensus()) && abs64(pfrom->nTimeOffset) > GetArg("-maxtimeoffset", MAXIMUM_TIME_OFFSET))
          {
              LogPrintf("peer=%d clock drifts too much (%d); disconnecting\n", pfrom->id, pfrom->nTimeOffset);
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_INVALID,
                                 strprintf("Clock drift cannot be greater than %d. Please, adjust your clock.", GetArg("-maxtimeoffset", MAXIMUM_TIME_OFFSET)));
              pfrom->fDisconnect = true;
              return false;
          }
          pfrom->fSuccessfullyConnected = true;
  
      }
  
  
      else if (pfrom->nVersion == 0)
      {
          // Must have a version message before anything else
          LOCK(cs_main);
          Misbehaving(pfrom->GetId(), 1);
          return false;
      }
  
  
      else if (strCommand == NetMsgType::VERACK)
      {
          pfrom->SetRecvVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
  
          // Mark this node as currently connected, so we update its timestamp later.
          if (pfrom->fNetworkNode) {
              LOCK(cs_main);
              State(pfrom->GetId())->fCurrentlyConnected = true;
          }
  
          if (pfrom->nVersion >= SENDHEADERS_VERSION) {
              // Tell our peer we prefer to receive headers rather than inv's
              // We send this to non-NODE NETWORK peers as well, because even
              // non-NODE NETWORK peers can announce blocks (such as pruning
              // nodes)
              pfrom->PushMessage(NetMsgType::SENDHEADERS);
          }
          if (pfrom->nVersion >= SHORT_IDS_BLOCKS_VERSION) {
              // Tell our peer we are willing to provide version-1 cmpctblocks
              // However, we do not request new block announcements using
              // cmpctblock messages.
              // We send this to non-NODE NETWORK peers as well, because
              // they may wish to request compact blocks from us
  //            bool fAnnounceUsingCMPCTBLOCK = false;
  //            uint64_t nCMPCTBLOCKVersion = 1;
  //            pfrom->PushMessage(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
          }
      }
  
  
      else if (strCommand == NetMsgType::ADDR)
      {
          vector<CAddress> vAddr;
          vRecv >> vAddr;
  
          // Don't want addr from older versions unless seeding
          if (pfrom->nVersion < CADDR_TIME_VERSION && addrman.size() > 1000)
              return true;
          if (vAddr.size() > 1000)
          {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 20);
              return error("message addr size() = %u", vAddr.size());
          }
  
          // Store the new addresses
          vector<CAddress> vAddrOk;
          int64_t nNow = GetAdjustedTime();
          int64_t nSince = nNow - 10 * 60;
          BOOST_FOREACH(CAddress& addr, vAddr)
          {
              boost::this_thread::interruption_point();
  
              if ((addr.nServices & REQUIRED_SERVICES) != REQUIRED_SERVICES)
                  continue;
  
              if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                  addr.nTime = nNow - 5 * 24 * 60 * 60;
              pfrom->AddAddressKnown(addr);
              bool fReachable = IsReachable(addr);
              if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable())
              {
                  // Relay to a limited number of other nodes
                  {
                      LOCK(cs_vNodes);
                      // Use deterministic randomness to send to the same nodes for 24 hours
                      // at a time so the addrKnowns of the chosen nodes prevent repeats
                      static const uint64_t salt0 = GetRand(std::numeric_limits<uint64_t>::max());
                      static const uint64_t salt1 = GetRand(std::numeric_limits<uint64_t>::max());
                      uint64_t hashAddr = addr.GetHash();
                      multimap<uint64_t, CNode*> mapMix;
                      const CSipHasher hasher = CSipHasher(salt0, salt1).Write(hashAddr << 32).Write((GetTime() + hashAddr) / (24*60*60));
                      BOOST_FOREACH(CNode* pnode, vNodes)
                      {
                          if (pnode->nVersion < CADDR_TIME_VERSION)
                              continue;
                          uint64_t hashKey = CSipHasher(hasher).Write(pnode->id).Finalize();
                          mapMix.insert(make_pair(hashKey, pnode));
                      }
                      int nRelayNodes = fReachable ? 2 : 1; // limited relaying of addresses outside our network(s)
                      for (multimap<uint64_t, CNode*>::iterator mi = mapMix.begin(); mi != mapMix.end() && nRelayNodes-- > 0; ++mi)
                          ((*mi).second)->PushAddress(addr);
                  }
              }
              // Do not store addresses outside our network
              if (fReachable)
                  vAddrOk.push_back(addr);
          }
          addrman.Add(vAddrOk, pfrom->addr, 2 * 60 * 60);
          if (vAddr.size() < 1000)
              pfrom->fGetAddr = false;
          if (pfrom->fOneShot)
              pfrom->fDisconnect = true;
      }
  
      else if (strCommand == NetMsgType::SENDHEADERS)
      {
          LOCK(cs_main);
          State(pfrom->GetId())->fPreferHeaders = true;
      }
  
      else if (strCommand == NetMsgType::SENDCMPCT)
      {
          bool fAnnounceUsingCMPCTBLOCK = false;
          uint64_t nCMPCTBLOCKVersion = 1;
          vRecv >> fAnnounceUsingCMPCTBLOCK >> nCMPCTBLOCKVersion;
          if (nCMPCTBLOCKVersion == 1) {
              LOCK(cs_main);
              State(pfrom->GetId())->fProvidesHeaderAndIDs = true;
              State(pfrom->GetId())->fPreferHeaderAndIDs = fAnnounceUsingCMPCTBLOCK;
          }
      }
  
  
      else if (strCommand == NetMsgType::INV)
      {
          vector<CInv> vInv;
          vRecv >> vInv;
          if (vInv.size() > MAX_INV_SZ)
          {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 20);
              return error("message inv size() = %u", vInv.size());
          }
  
          bool fBlocksOnly = !fRelayTxes;
  
          // Allow whitelisted peers to send data other than blocks in blocks only mode if whitelistrelay is true
          if (pfrom->fWhitelisted && GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY))
              fBlocksOnly = false;
  
          LOCK(cs_main);
  
          uint32_t nFetchFlags = GetFetchFlags(pfrom, chainActive.Tip(), chainparams.GetConsensus());
  
          std::vector<CInv> vToFetch;
  
          for (unsigned int nInv = 0; nInv < vInv.size(); nInv++)
          {
              CInv &inv = vInv[nInv];
  
              boost::this_thread::interruption_point();
  
              bool fAlreadyHave = AlreadyHave(inv);
              LogPrint("net", "got inv: %s  %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom->id);
  
              if (inv.type == MSG_TX) {
                  inv.type |= nFetchFlags;
              }
  
              if (inv.type == MSG_BLOCK) {
                  UpdateBlockAvailability(pfrom->GetId(), inv.hash);
                  if (!fAlreadyHave && !fImporting && !fReindex && !mapBlocksInFlight.count(inv.hash)) {
                      // First request the headers preceding the announced block. In the normal fully-synced
                      // case where a new block is announced that succeeds the current tip (no reorganization),
                      // there are no such headers.
                      // Secondly, and only when we are close to being synced, we request the announced block directly,
                      // to avoid an extra round-trip. Note that we must *first* ask for the headers, so by the
                      // time the block arrives, the header chain leading up to it is already validated. Not
                      // doing this will result in the received block being rejected as an orphan in case it is
                      // not a direct successor.
                      pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), inv.hash);
                      CNodeState *nodestate = State(pfrom->GetId());
                      if (CanDirectFetch(chainparams.GetConsensus()) &&
                          nodestate->nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER &&
                          (!IsWitnessEnabled(chainActive.Tip(), chainparams.GetConsensus()) || State(pfrom->GetId())->fHaveWitness)) {
                          inv.type |= nFetchFlags;
  //                        if (nodestate->fProvidesHeaderAndIDs && !(nLocalServices & NODE_WITNESS))
  //                            vToFetch.push_back(CInv(MSG_CMPCT_BLOCK, inv.hash));
  //                        else
                              vToFetch.push_back(inv);
                          // Mark block as in flight already, even though the actual "getdata" message only goes out
                          // later (within the same cs_main lock, though).
                          MarkBlockAsInFlight(pfrom->GetId(), inv.hash, chainparams.GetConsensus());
                      }
                      LogPrint("net", "getheaders (%d) %s to peer=%d\n", pindexBestHeader->nHeight, inv.hash.ToString(), pfrom->id);
                  }
              }
              else
              {
                  pfrom->AddInventoryKnown(inv);
                  if (fBlocksOnly)
                      LogPrint("net", "transaction (%s) inv sent in violation of protocol peer=%d\n", inv.hash.ToString(), pfrom->id);
                  else if (!fAlreadyHave && !fImporting && !fReindex && !IsInitialBlockDownload())
                      pfrom->AskFor(inv);
              }
  
              // Track requests for our stuff
              GetMainSignals().Inventory(inv.hash);
  
              if (pfrom->nSendSize > (SendBufferSize() * 2)) {
                  Misbehaving(pfrom->GetId(), 50);
                  return error("send buffer size() = %u", pfrom->nSendSize);
              }
          }
  
          if (!vToFetch.empty())
              pfrom->PushMessage(NetMsgType::GETDATA, vToFetch);
      }
  
  
      else if (strCommand == NetMsgType::GETDATA)
      {
          vector<CInv> vInv;
          vRecv >> vInv;
          if (vInv.size() > MAX_INV_SZ)
          {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 20);
              return error("message getdata size() = %u", vInv.size());
          }
  
          if (fDebug || (vInv.size() != 1))
              LogPrint("net", "received getdata (%u invsz) peer=%d\n", vInv.size(), pfrom->id);
  
          if ((fDebug && vInv.size() > 0) || (vInv.size() == 1))
              LogPrint("net", "received getdata for: %s peer=%d\n", vInv[0].ToString(), pfrom->id);
  
          pfrom->vRecvGetData.insert(pfrom->vRecvGetData.end(), vInv.begin(), vInv.end());
          ProcessGetData(pfrom, chainparams.GetConsensus());
      }
  
  
      else if (strCommand == NetMsgType::GETBLOCKS)
      {
          CBlockLocator locator;
          uint256 hashStop;
          vRecv >> locator >> hashStop;
  
          LOCK(cs_main);
  
          // Find the last block the caller has in the main chain
          CBlockIndex* pindex = FindForkInGlobalIndex(chainActive, locator);
  
          // Send the rest of the chain
          if (pindex)
              pindex = chainActive.Next(pindex);
          int nLimit = 500;
          LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit, pfrom->id);
          for (; pindex; pindex = chainActive.Next(pindex))
          {
              if (pindex->GetBlockHash() == hashStop)
              {
                  LogPrint("net", "  getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
                  break;
              }
              // If pruning, don't inv blocks unless we have on disk and are likely to still have
              // for some reasonable time window (1 hour) that block relay might require.
              const int nPrunedBlocksLikelyToHave = MIN_BLOCKS_TO_KEEP - 3600 / chainparams.GetConsensus().nPowTargetSpacing;
              if (fPruneMode && (!(pindex->nStatus & BLOCK_HAVE_DATA) || pindex->nHeight <= chainActive.Tip()->nHeight - nPrunedBlocksLikelyToHave))
              {
                  LogPrint("net", " getblocks stopping, pruned or too old block at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
                  break;
              }
              pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
              if (--nLimit <= 0)
              {
                  // When this block is requested, we'll send an inv that'll
                  // trigger the peer to getblocks the next batch of inventory.
                  LogPrint("net", "  getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
                  pfrom->hashContinue = pindex->GetBlockHash();
                  break;
              }
          }
      }
  
  
      else if (strCommand == NetMsgType::GETBLOCKTXN)
      {
          BlockTransactionsRequest req;
          vRecv >> req;
  
          BlockMap::iterator it = mapBlockIndex.find(req.blockhash);
          if (it == mapBlockIndex.end() || !(it->second->nStatus & BLOCK_HAVE_DATA)) {
              LogPrintf("Peer %d sent us a getblocktxn for a block we don't have", pfrom->id);
              return true;
          }
  
          if (it->second->nHeight < chainActive.Height() - 15) {
              LogPrint("net", "Peer %d sent us a getblocktxn for a block > 15 deep", pfrom->id);
              return true;
          }
  
          CBlock block;
          assert(ReadBlockFromDisk(block, it->second, chainparams.GetConsensus()));
  
          BlockTransactions resp(req);
          for (size_t i = 0; i < req.indexes.size(); i++) {
              if (req.indexes[i] >= block.vtx.size()) {
                  Misbehaving(pfrom->GetId(), 100);
                  LogPrintf("Peer %d sent us a getblocktxn with out-of-bounds tx indices", pfrom->id);
                  return true;
              }
              resp.txn[i] = block.vtx[req.indexes[i]];
          }
          pfrom->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCKTXN, resp);
      }
  
  
      else if (strCommand == NetMsgType::GETHEADERS)
      {
          CBlockLocator locator;
          uint256 hashStop;
          vRecv >> locator >> hashStop;
  
          LOCK(cs_main);
          if (IsInitialBlockDownload() && !pfrom->fWhitelisted) {
              LogPrint("net", "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom->id);
              return true;
          }
  
          CNodeState *nodestate = State(pfrom->GetId());
          CBlockIndex* pindex = NULL;
          if (locator.IsNull())
          {
              // If locator is null, return the hashStop block
              BlockMap::iterator mi = mapBlockIndex.find(hashStop);
              if (mi == mapBlockIndex.end())
                  return true;
              pindex = (*mi).second;
          }
          else
          {
              // Find the last block the caller has in the main chain
              pindex = FindForkInGlobalIndex(chainActive, locator);
              if (pindex)
                  pindex = chainActive.Next(pindex);
          }
  
          // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx count at the end
          vector<CBlock> vHeaders;
          int nLimit = MAX_HEADERS_RESULTS;
          LogPrint("net", "getheaders %d to %s from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.ToString(), pfrom->id);
          for (; pindex; pindex = chainActive.Next(pindex))
          {
              vHeaders.push_back(pindex->GetBlockHeader());
              if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop)
                  break;
          }
          // pindex can be NULL either if we sent chainActive.Tip() OR
          // if our peer has chainActive.Tip() (and thus we are sending an empty
          // headers message). In both cases it's safe to update
          // pindexBestHeaderSent to be our tip.
          nodestate->pindexBestHeaderSent = pindex ? pindex : chainActive.Tip();
          pfrom->PushMessage(NetMsgType::HEADERS, vHeaders);
      }
  
  
      else if (strCommand == NetMsgType::TX)
      {
          // Stop processing the transaction early if
          // We are in blocks only mode and peer is either not whitelisted or whitelistrelay is off
          if (!fRelayTxes && (!pfrom->fWhitelisted || !GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY)))
          {
              LogPrint("net", "transaction sent in violation of protocol peer=%d\n", pfrom->id);
              return true;
          }
  
          deque<COutPoint> vWorkQueue;
          vector<uint256> vEraseQueue;
          CTransaction tx;
          vRecv >> tx;
  
          LogPrint("net", "Received tx %s peer=%d\n%s\n", tx.GetHash().ToString(), pfrom->id, tx.ToString());
  
          CInv inv(MSG_TX, tx.GetHash());
          pfrom->AddInventoryKnown(inv);
  
          LOCK(cs_main);
  
          bool fMissingInputs = false;
          CValidationState state;
  
          pfrom->setAskFor.erase(inv.hash);
          mapAlreadyAskedFor.erase(inv.hash);
  
          if (!AlreadyHave(inv) && AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs)) {
              mempool.check(pcoinsTip);
              RelayTransaction(tx);
              for (unsigned int i = 0; i < tx.vout.size(); i++) {
                  vWorkQueue.emplace_back(inv.hash, i);
              }
  
              pfrom->nLastTXTime = GetTime();
  
              LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n",
                  pfrom->id,
                  tx.GetHash().ToString(),
                  mempool.size(), mempool.DynamicMemoryUsage() / 1000);
  
              // Recursively process any orphan transactions that depended on this one
              set<NodeId> setMisbehaving;
              while (!vWorkQueue.empty()) {
                  auto itByPrev = mapOrphanTransactionsByPrev.find(vWorkQueue.front());
                  vWorkQueue.pop_front();
                  if (itByPrev == mapOrphanTransactionsByPrev.end())
                      continue;
                  for (auto mi = itByPrev->second.begin();
                       mi != itByPrev->second.end();
                       ++mi)
                  {
                      const CTransaction& orphanTx = (*mi)->second.tx;
                      const uint256& orphanHash = orphanTx.GetHash();
                      NodeId fromPeer = (*mi)->second.fromPeer;
                      bool fMissingInputs2 = false;
                      // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan
                      // resolution (that is, feeding people an invalid transaction based on LegitTxX in order to get
                      // anyone relaying LegitTxX banned)
                      CValidationState stateDummy;
  
  
                      if (setMisbehaving.count(fromPeer))
                          continue;
                      if (AcceptToMemoryPool(mempool, stateDummy, orphanTx, true, &fMissingInputs2)) {
                          LogPrint("mempool", "   accepted orphan tx %s\n", orphanHash.ToString());
                          RelayTransaction(orphanTx);
                          for (unsigned int i = 0; i < orphanTx.vout.size(); i++) {
                              vWorkQueue.emplace_back(orphanHash, i);
                          }
                          vEraseQueue.push_back(orphanHash);
                      }
                      else if (!fMissingInputs2)
                      {
                          int nDos = 0;
                          if (stateDummy.IsInvalid(nDos) && nDos > 0 && (!state.CorruptionPossible() || State(fromPeer)->fHaveWitness))
                          {
                              // Punish peer that gave us an invalid orphan tx
                              Misbehaving(fromPeer, nDos);
                              setMisbehaving.insert(fromPeer);
                              LogPrint("mempool", "   invalid orphan tx %s\n", orphanHash.ToString());
                          }
                          // Has inputs but not accepted to mempool
                          // Probably non-standard or insufficient fee/priority
                          LogPrint("mempool", "   removed orphan tx %s\n", orphanHash.ToString());
                          vEraseQueue.push_back(orphanHash);
                          if (!stateDummy.CorruptionPossible()) {
                              assert(recentRejects);
                              recentRejects->insert(orphanHash);
                          }
                      }
                      mempool.check(pcoinsTip);
                  }
              }
  
              BOOST_FOREACH(uint256 hash, vEraseQueue)
                  EraseOrphanTx(hash);
          }
          else if (fMissingInputs)
          {
              bool fRejectedParents = false; // It may be the case that the orphans parents have all been rejected
              BOOST_FOREACH(const CTxIn& txin, tx.vin) {
                  if (recentRejects->contains(txin.prevout.hash)) {
                      fRejectedParents = true;
                      break;
                  }
              }
              if (!fRejectedParents) {
                  BOOST_FOREACH(const CTxIn& txin, tx.vin) {
                      CInv inv(MSG_TX, txin.prevout.hash);
                      pfrom->AddInventoryKnown(inv);
                      if (!AlreadyHave(inv)) pfrom->AskFor(inv);
                  }
                  AddOrphanTx(tx, pfrom->GetId());
  
                  // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
                  unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
                  unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
                  if (nEvicted > 0)
                      LogPrint("mempool", "mapOrphan overflow, removed %u tx\n", nEvicted);
              } else {
                  LogPrint("mempool", "not keeping orphan with rejected parents %s\n",tx.GetHash().ToString());
              }
          } else {
              if (!state.CorruptionPossible()) {
                  assert(recentRejects);
                  recentRejects->insert(tx.GetHash());
              }
  
              if (pfrom->fWhitelisted && GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY)) {
                  // Always relay transactions received from whitelisted peers, even
                  // if they were already in the mempool or rejected from it due
                  // to policy, allowing the node to function as a gateway for
                  // nodes hidden behind it.
                  //
                  // Never relay transactions that we would assign a non-zero DoS
                  // score for, as we expect peers to do the same with us in that
                  // case.
                  int nDoS = 0;
                  if (!state.IsInvalid(nDoS) || nDoS == 0) {
                      LogPrintf("Force relaying tx %s from whitelisted peer=%d\n", tx.GetHash().ToString(), pfrom->id);
                      RelayTransaction(tx);
                  } else {
                      LogPrintf("Not relaying invalid transaction %s from whitelisted peer=%d (%s)\n", tx.GetHash().ToString(), pfrom->id, FormatStateMessage(state));
                  }
              }
          }
          int nDoS = 0;
          if (state.IsInvalid(nDoS))
          {
              LogPrint("mempoolrej", "%s from peer=%d was not accepted: %s\n", tx.GetHash().ToString(),
                  pfrom->id,
                  FormatStateMessage(state));
              if (state.GetRejectCode() < REJECT_INTERNAL) // Never send AcceptToMemoryPool's internal codes over P2P
                  pfrom->PushMessage(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
                                     state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
              if (nDoS > 0 && (!state.CorruptionPossible() || State(pfrom->id)->fHaveWitness)) {
                  // When a non-witness-supporting peer gives us a transaction that would
                  // be accepted if witness validation was off, we can't blame them for it.
                  Misbehaving(pfrom->GetId(), nDoS);
              }
          }
          FlushStateToDisk(state, FLUSH_STATE_PERIODIC);
      }
  
  
      else if (strCommand == NetMsgType::CMPCTBLOCK && !fImporting && !fReindex) // Ignore blocks received while importing
      {
          CBlockHeaderAndShortTxIDs cmpctblock;
          vRecv >> cmpctblock;
  
          LOCK(cs_main);
  
          if (mapBlockIndex.find(cmpctblock.header.hashPrevBlock) == mapBlockIndex.end()) {
              // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers
              if (!IsInitialBlockDownload())
                  pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256());
              return true;
          }
  
          CBlockIndex *pindex = NULL;
          CValidationState state;
          if (!AcceptBlockHeader(cmpctblock.header, state, chainparams, &pindex)) {
              int nDoS;
              if (state.IsInvalid(nDoS)) {
                  if (nDoS > 0)
                      Misbehaving(pfrom->GetId(), nDoS);
                  LogPrintf("Peer %d sent us invalid header via cmpctblock\n", pfrom->id);
                  return true;
              }
          }
  
          // If AcceptBlockHeader returned true, it set pindex
          assert(pindex);
          UpdateBlockAvailability(pfrom->GetId(), pindex->GetBlockHash());
  
          std::map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator blockInFlightIt = mapBlocksInFlight.find(pindex->GetBlockHash());
          bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end();
  
          if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here
              return true;
  
          if (pindex->nChainWork <= chainActive.Tip()->nChainWork || // We know something better
                  pindex->nTx != 0) { // We had this block at some point, but pruned it
              if (fAlreadyInFlight) {
                  // We requested this block for some reason, but our mempool will probably be useless
                  // so we just grab the block via normal getdata
                  std::vector<CInv> vInv(1);
                  vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                  pfrom->PushMessage(NetMsgType::GETDATA, vInv);
              }
              return true;
          }
  
          // If we're not close to tip yet, give up and let parallel block fetch work its magic
          if (!fAlreadyInFlight && !CanDirectFetch(chainparams.GetConsensus()))
              return true;
  
          CNodeState *nodestate = State(pfrom->GetId());
  
          // We want to be a bit conservative just to be extra careful about DoS
          // possibilities in compact block processing...
          if (pindex->nHeight <= chainActive.Height() + 2) {
              if ((!fAlreadyInFlight && nodestate->nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) ||
                   (fAlreadyInFlight && blockInFlightIt->second.first == pfrom->GetId())) {
                  list<QueuedBlock>::iterator *queuedBlockIt = NULL;
                  if (!MarkBlockAsInFlight(pfrom->GetId(), pindex->GetBlockHash(), chainparams.GetConsensus(), pindex, &queuedBlockIt)) {
                      if (!(*queuedBlockIt)->partialBlock)
                          (*queuedBlockIt)->partialBlock.reset(new PartiallyDownloadedBlock(&mempool));
                      else {
                          // The block was already in flight using compact blocks from the same peer
                          LogPrint("net", "Peer sent us compact block we were already syncing!\n");
                          return true;
                      }
                  }
  
                  PartiallyDownloadedBlock& partialBlock = *(*queuedBlockIt)->partialBlock;
                  ReadStatus status = partialBlock.InitData(cmpctblock);
                  if (status == READ_STATUS_INVALID) {
                      MarkBlockAsReceived(pindex->GetBlockHash()); // Reset in-flight state in case of whitelist
                      Misbehaving(pfrom->GetId(), 100);
                      LogPrintf("Peer %d sent us invalid compact block\n", pfrom->id);
                      return true;
                  } else if (status == READ_STATUS_FAILED) {
                      // Duplicate txindexes, the block is now in-flight, so just request it
                      std::vector<CInv> vInv(1);
                      vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                      pfrom->PushMessage(NetMsgType::GETDATA, vInv);
                      return true;
                  }
  
                  BlockTransactionsRequest req;
                  for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
                      if (!partialBlock.IsTxAvailable(i))
                          req.indexes.push_back(i);
                  }
                  if (req.indexes.empty()) {
                      // Dirty hack to jump to BLOCKTXN code (TODO: move message handling into their own functions)
                      BlockTransactions txn;
                      txn.blockhash = cmpctblock.header.GetHash();
                      CDataStream blockTxnMsg(SER_NETWORK, PROTOCOL_VERSION);
                      blockTxnMsg << txn;
                      return ProcessMessage(pfrom, NetMsgType::BLOCKTXN, blockTxnMsg, nTimeReceived, chainparams);
                  } else {
                      req.blockhash = pindex->GetBlockHash();
                      pfrom->PushMessage(NetMsgType::GETBLOCKTXN, req);
                  }
              }
          } else {
              if (fAlreadyInFlight) {
                  // We requested this block, but its far into the future, so our
                  // mempool will probably be useless - request the block normally
                  std::vector<CInv> vInv(1);
                  vInv[0] = CInv(MSG_BLOCK, cmpctblock.header.GetHash());
                  pfrom->PushMessage(NetMsgType::GETDATA, vInv);
                  return true;
              } else {
                  // If this was an announce-cmpctblock, we want the same treatment as a header message
                  // Dirty hack to process as if it were just a headers message (TODO: move message handling into their own functions)
                  std::vector<CBlock> headers;
                  headers.push_back(cmpctblock.header);
                  CDataStream vHeadersMsg(SER_NETWORK, PROTOCOL_VERSION);
                  vHeadersMsg << headers;
                  return ProcessMessage(pfrom, NetMsgType::HEADERS, vHeadersMsg, nTimeReceived, chainparams);
              }
          }
  
          CheckBlockIndex(chainparams.GetConsensus());
      }
  
      else if (strCommand == NetMsgType::BLOCKTXN && !fImporting && !fReindex) // Ignore blocks received while importing
      {
          BlockTransactions resp;
          vRecv >> resp;
  
          LOCK(cs_main);
  
          map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator it = mapBlocksInFlight.find(resp.blockhash);
          if (it == mapBlocksInFlight.end() || !it->second.second->partialBlock ||
                  it->second.first != pfrom->GetId()) {
              LogPrint("net", "Peer %d sent us block transactions for block we weren't expecting\n", pfrom->id);
              return true;
          }
  
          PartiallyDownloadedBlock& partialBlock = *it->second.second->partialBlock;
          CBlock block;
          ReadStatus status = partialBlock.FillBlock(block, resp.txn);
          if (status == READ_STATUS_INVALID) {
              MarkBlockAsReceived(resp.blockhash); // Reset in-flight state in case of whitelist
              LogPrintf("Peer %d sent us invalid compact block/non-matching block transactions\n", pfrom->id);
              return true;
          } else if (status == READ_STATUS_FAILED) {
              // Might have collided, fall back to getdata now :(
              std::vector<CInv> invs;
              invs.push_back(CInv(MSG_BLOCK, resp.blockhash));
              pfrom->PushMessage(NetMsgType::GETDATA, invs);
          } else {
              CValidationState state;
              ProcessNewBlock(state, chainparams, pfrom, &block, false, NULL);
              int nDoS;
              if (state.IsInvalid(nDoS)) {
                  assert (state.GetRejectCode() < REJECT_INTERNAL); // Blocks are never rejected with internal reject codes
                  pfrom->PushMessage(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
                                     state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), block.GetHash());
                  if (nDoS > 0) {
                      LOCK(cs_main);
                      Misbehaving(pfrom->GetId(), nDoS);
                  }
              }
          }
      }
  
  
      else if (strCommand == NetMsgType::HEADERS && !fImporting && !fReindex) // Ignore headers received while importing
      {
          std::vector<CBlock> headers;
  
          // Bypass the normal CBlock deserialization, as we don't want to risk deserializing 2000 full blocks.
          unsigned int nCount = ReadCompactSize(vRecv);
  
          if (nCount > MAX_HEADERS_RESULTS) {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 20);
              return error("headers message size = %u", nCount);
          }
          headers.resize(nCount);
  
          for (unsigned int n = 0; n < nCount; n++) {
  
              vRecv >> headers[n];
  
              //ReadCompactSize(vRecv); // ignore tx count; assume it is 0.
          }
  
          {
          LOCK(cs_main);
  
          if (nCount == 0) {
              // Nothing interesting. Stop asking this peers for more headers.
              return true;
          }
  
          CNodeState *nodestate = State(pfrom->GetId());
  
          // If this looks like it could be a block announcement (nCount <
          // MAX_BLOCKS_TO_ANNOUNCE), use special logic for handling headers that
          // don't connect:
          // - Send a getheaders message in response to try to connect the chain.
          // - The peer can send up to MAX_UNCONNECTING_HEADERS in a row that
          //   don't connect before giving DoS points
          // - Once a headers message is received that is valid and does connect,
          //   nUnconnectingHeaders gets reset back to 0.
          if (mapBlockIndex.find(headers[0].hashPrevBlock) == mapBlockIndex.end() && nCount < MAX_BLOCKS_TO_ANNOUNCE) {
              nodestate->nUnconnectingHeaders++;
              pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256());
              LogPrint("net", "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, nUnconnectingHeaders=%d)\n",
                      headers[0].GetHash().ToString(),
                      headers[0].hashPrevBlock.ToString(),
                      pindexBestHeader->nHeight,
                      pfrom->id, nodestate->nUnconnectingHeaders);
              // Set hashLastUnknownBlock for this peer, so that if we
              // eventually get the headers - even from a different peer -
              // we can use this peer to download.
              UpdateBlockAvailability(pfrom->GetId(), headers.back().GetHash());
  
              if (nodestate->nUnconnectingHeaders % MAX_UNCONNECTING_HEADERS == 0) {
                  Misbehaving(pfrom->GetId(), 20);
              }
  
              return true;
          }
  
          bool ret = true;
          bool bFirst = true;
          string strError = "";
  
          int nFirst = 0;
          int nLast = 0;
  
          CBlockIndex *pindexLast = NULL;
  
          BOOST_FOREACH(const CBlock& header, headers) {
              CValidationState state;
              if (pindexLast != NULL && header.hashPrevBlock != pindexLast->GetBlockHash()) {
                  Misbehaving(pfrom->GetId(), 20);
                  ret = false;
                  strError = "non-continuous headers sequence";
                  break;
              }
              CBlockHeader pblockheader = CBlockHeader(header);
              if (!AcceptBlockHeader(pblockheader, state, chainparams, &pindexLast)) {
                  int nDoS;
                  if (state.IsInvalid(nDoS)) {
                      if (nDoS > 0)
                          Misbehaving(pfrom->GetId(), nDoS);
                      ret = false;
                      strError = "invalid header received";
                      break;
                  }
              }
              if (pindexLast) {
                  nLast = pindexLast->nHeight;
                  if (bFirst){
                      nFirst = pindexLast->nHeight;
                      bFirst = false;
                  }
              }
          }
  
          if(GetBoolArg("-headerspamfilter", DEFAULT_HEADER_SPAM_FILTER) && !IsInitialBlockDownload())
          {
              LOCK(cs_main);
              CValidationState state;
              CNodeState *nodestate = State(pfrom->GetId());
              CNodeHeaders& headers = ServiceHeaders(nodestate->address);
              headers.addHeaders(nFirst, nLast);
              int nDoS;
              ret = headers.updateState(state, ret);
              if (state.IsInvalid(nDoS)) {
                  if (nDoS > 0)
                      Misbehaving(pfrom->GetId(), nDoS);
                  ret = false;
                  strError = strError!="" ? strError + " / ": "";
                  strError = "header spam protection";
              }
          }
  
          if (!ret)
              return error(strError.c_str());
  
          if (nodestate->nUnconnectingHeaders > 0) {
              LogPrint("net", "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n", pfrom->id, nodestate->nUnconnectingHeaders);
          }
          nodestate->nUnconnectingHeaders = 0;
  
          assert(pindexLast);
          UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash());
  
          if (nCount == MAX_HEADERS_RESULTS) {
              // Headers message had its maximum size; the peer may have more headers.
              // TODO: optimize: if pindexLast is an ancestor of chainActive.Tip or pindexBestHeader, continue
              // from there instead.
              LogPrint("net", "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom->id, pfrom->nStartingHeight);
              pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexLast), uint256());
          }
  
          bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
  
          // If this set of headers is valid and ends in a block with at least as
          // much work as our tip, download as much as possible.
          if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) && chainActive.Tip()->nChainWork <= pindexLast->nChainWork) {
              vector<CBlockIndex *> vToFetch;
              CBlockIndex *pindexWalk = pindexLast;
              // Calculate all the blocks we'd need to switch to pindexLast, up to a limit.
              while (pindexWalk && !chainActive.Contains(pindexWalk) && vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                  if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) &&
                          !mapBlocksInFlight.count(pindexWalk->GetBlockHash()) &&
                          (!IsWitnessEnabled(pindexWalk->pprev, chainparams.GetConsensus()) || State(pfrom->GetId())->fHaveWitness)) {
                      // We don't have this block, and it's not yet in flight.
                      vToFetch.push_back(pindexWalk);
                  }
                  pindexWalk = pindexWalk->pprev;
              }
              // If pindexWalk still isn't on our main chain, we're looking at a
              // very large reorg at a time we think we're close to caught up to
              // the main chain -- this shouldn't really happen.  Bail out on the
              // direct fetch and rely on parallel download instead.
              if (!chainActive.Contains(pindexWalk)) {
                  LogPrint("net", "Large reorg, won't direct fetch to %s (%d)\n",
                          pindexLast->GetBlockHash().ToString(),
                          pindexLast->nHeight);
              } else {
                  vector<CInv> vGetData;
                  // Download as much as possible, from earliest to latest.
                  BOOST_REVERSE_FOREACH(CBlockIndex *pindex, vToFetch) {
                      if (nodestate->nBlocksInFlight >= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                          // Can't download any more from this peer
                          break;
                      }
                      uint32_t nFetchFlags = GetFetchFlags(pfrom, pindex->pprev, chainparams.GetConsensus());
                      vGetData.push_back(CInv(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash()));
                      MarkBlockAsInFlight(pfrom->GetId(), pindex->GetBlockHash(), chainparams.GetConsensus(), pindex);
                      LogPrint("net", "Requesting block %s from  peer=%d\n",
                              pindex->GetBlockHash().ToString(), pfrom->id);
                  }
                  if (vGetData.size() > 1) {
                      LogPrint("net", "Downloading blocks toward %s (%d) via headers direct fetch\n",
                              pindexLast->GetBlockHash().ToString(), pindexLast->nHeight);
                  }
                  if (vGetData.size() > 0) {
  //                    if (nodestate->fProvidesHeaderAndIDs && vGetData.size() == 1 && mapBlocksInFlight.size() == 1 && pindexLast->pprev->IsValid(BLOCK_VALID_CHAIN) && !(nLocalServices & NODE_WITNESS)) {
  //                        // We seem to be rather well-synced, so it appears pfrom was the first to provide us
  //                        // with this block! Let's get them to announce using compact blocks in the future.
  //                        MaybeSetPeerAsAnnouncingHeaderAndIDs(nodestate, pfrom);
  //                        // In any case, we want to download using a compact block, not a regular one
  //                        vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
  //                    }
                      pfrom->PushMessage(NetMsgType::GETDATA, vGetData);
                  }
              }
          }
  
          CheckBlockIndex(chainparams.GetConsensus());
          }
  
          NotifyHeaderTip();
      }
  
      else if (strCommand == NetMsgType::BLOCK && !fImporting && !fReindex) // Ignore blocks received while importing
      {
          CBlock block;
          vRecv >> block;
  
          LogPrint("net", "received block %s peer=%d\n%s\n", block.GetHash().ToString(), pfrom->id, block.ToString());
  
          CValidationState state;
          // Process all blocks from whitelisted peers, even if not requested,
          // unless we're still syncing with the network.
          // Such an unrequested block may still be processed, subject to the
          // conditions in AcceptBlock().
          bool forceProcessing = pfrom->fWhitelisted && !IsInitialBlockDownload();
          ProcessNewBlock(state, chainparams, pfrom, &block, forceProcessing, NULL);
          int nDoS;
          if (state.IsInvalid(nDoS)) {
              assert (state.GetRejectCode() < REJECT_INTERNAL); // Blocks are never rejected with internal reject codes
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
                                 state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), block.GetHash());
              if (nDoS > 0) {
                  LOCK(cs_main);
                  Misbehaving(pfrom->GetId(), nDoS);
              }
          }
  
      }
  
  
      else if (strCommand == NetMsgType::GETADDR)
      {
          // This asymmetric behavior for inbound and outbound connections was introduced
          // to prevent a fingerprinting attack: an attacker can send specific fake addresses
          // to users' AddrMan and later request them by sending getaddr messages.
          // Making nodes which are behind NAT and can only make outgoing connections ignore
          // the getaddr message mitigates the attack.
          if (!pfrom->fInbound) {
              LogPrint("net", "Ignoring \"getaddr\" from outbound connection. peer=%d\n", pfrom->id);
              return true;
          }
  
          // Only send one GetAddr response per connection to reduce resource waste
          //  and discourage addr stamping of INV announcements.
          if (pfrom->fSentAddr) {
              LogPrint("net", "Ignoring repeated \"getaddr\". peer=%d\n", pfrom->id);
              return true;
          }
          pfrom->fSentAddr = true;
  
          pfrom->vAddrToSend.clear();
          vector<CAddress> vAddr = addrman.GetAddr();
          BOOST_FOREACH(const CAddress &addr, vAddr)
              pfrom->PushAddress(addr);
      }
  
  
      else if (strCommand == NetMsgType::MEMPOOL)
      {
          if (!(nLocalServices & NODE_BLOOM) && !pfrom->fWhitelisted)
          {
              LogPrint("net", "mempool request with bloom filters disabled, disconnect peer=%d\n", pfrom->GetId());
              pfrom->fDisconnect = true;
              return true;
          }
  
          if (CNode::OutboundTargetReached(false) && !pfrom->fWhitelisted)
          {
              LogPrint("net", "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom->GetId());
              pfrom->fDisconnect = true;
              return true;
          }
  
          LOCK(pfrom->cs_inventory);
          pfrom->fSendMempool = true;
      }
  
  
      else if (strCommand == NetMsgType::PING)
      {
          if (pfrom->nVersion > BIP0031_VERSION)
          {
              uint64_t nonce = 0;
              vRecv >> nonce;
              // Echo the message back with the nonce. This allows for two useful features:
              //
              // 1) A remote node can quickly check if the connection is operational
              // 2) Remote nodes can measure the latency of the network thread. If this node
              //    is overloaded it won't respond to pings quickly and the remote node can
              //    avoid sending us more work, like chain download requests.
              //
              // The nonce stops the remote getting confused between different pings: without
              // it, if the remote node sends a ping once per second and this node takes 5
              // seconds to respond to each, the 5th ping the remote sends would appear to
              // return very quickly.
              pfrom->PushMessage(NetMsgType::PONG, nonce);
          }
      }
  
  
      else if (strCommand == NetMsgType::PONG)
      {
          int64_t pingUsecEnd = nTimeReceived;
          uint64_t nonce = 0;
          size_t nAvail = vRecv.in_avail();
          bool bPingFinished = false;
          std::string sProblem;
  
          if (nAvail >= sizeof(nonce)) {
              vRecv >> nonce;
  
              // Only process pong message if there is an outstanding ping (old ping without nonce should never pong)
              if (pfrom->nPingNonceSent != 0) {
                  if (nonce == pfrom->nPingNonceSent) {
                      // Matching pong received, this ping is no longer outstanding
                      bPingFinished = true;
                      int64_t pingUsecTime = pingUsecEnd - pfrom->nPingUsecStart;
                      if (pingUsecTime > 0) {
                          // Successful ping time measurement, replace previous
                          pfrom->nPingUsecTime = pingUsecTime;
                          pfrom->nMinPingUsecTime = std::min(pfrom->nMinPingUsecTime, pingUsecTime);
                      } else {
                          // This should never happen
                          sProblem = "Timing mishap";
                      }
                  } else {
                      // Nonce mismatches are normal when pings are overlapping
                      sProblem = "Nonce mismatch";
                      if (nonce == 0) {
                          // This is most likely a bug in another implementation somewhere; cancel this ping
                          bPingFinished = true;
                          sProblem = "Nonce zero";
                      }
                  }
              } else {
                  sProblem = "Unsolicited pong without ping";
              }
          } else {
              // This is most likely a bug in another implementation somewhere; cancel this ping
              bPingFinished = true;
              sProblem = "Short payload";
          }
  
          if (!(sProblem.empty())) {
              LogPrint("net", "pong peer=%d: %s, %x expected, %x received, %u bytes\n",
                  pfrom->id,
                  sProblem,
                  pfrom->nPingNonceSent,
                  nonce,
                  nAvail);
          }
          if (bPingFinished) {
              pfrom->nPingNonceSent = 0;
          }
      }
  
  
      else if (strCommand == NetMsgType::FILTERLOAD)
      {
          CBloomFilter filter;
          vRecv >> filter;
  
          LOCK(pfrom->cs_filter);
  
          if (!filter.IsWithinSizeConstraints())
          {
              // There is no excuse for sending a too-large filter
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 100);
          }
          else
          {
              delete pfrom->pfilter;
              pfrom->pfilter = new CBloomFilter(filter);
              pfrom->pfilter->UpdateEmptyFull();
          }
          pfrom->fRelayTxes = true;
      }
  
  
      else if (strCommand == NetMsgType::FILTERADD)
      {
          vector<unsigned char> vData;
          vRecv >> vData;
  
          // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object,
          // and thus, the maximum size any matched object can have) in a filteradd message
          if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE)
          {
              LOCK(cs_main);
              Misbehaving(pfrom->GetId(), 100);
          } else {
              LOCK(pfrom->cs_filter);
              if (pfrom->pfilter)
                  pfrom->pfilter->insert(vData);
              else
              {
                  LOCK(cs_main);
                  Misbehaving(pfrom->GetId(), 100);
              }
          }
      }
  
  
      else if (strCommand == NetMsgType::FILTERCLEAR)
      {
          LOCK(pfrom->cs_filter);
          delete pfrom->pfilter;
          pfrom->pfilter = new CBloomFilter();
          pfrom->fRelayTxes = true;
      }
  
  
      else if (strCommand == NetMsgType::REJECT)
      {
          try {
              string strMsg; unsigned char ccode; string strReason;
              vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
  
              ostringstream ss;
              ss << strMsg << " code " << itostr(ccode) << ": " << strReason;
  
              if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX)
              {
                  uint256 hash;
                  vRecv >> hash;
                  ss << ": hash " << hash.ToString();
              }
              if(fDebug || ccode == REJECT_OBSOLETE)
                  LogPrintf("Nodes are rejecting our messages. Reason: %s\n", SanitizeString(ss.str()));
          } catch (const std::ios_base::failure&) {
              // Avoid feedback loops by preventing reject messages from triggering a new reject message.
              if(fDebug)
                  LogPrint("net", "Unparseable reject message received\n");
          }
      }
  
      else if (strCommand == NetMsgType::FEEFILTER) {
          CAmount newFeeFilter = 0;
          vRecv >> newFeeFilter;
          if (MoneyRange(newFeeFilter)) {
              {
                  LOCK(pfrom->cs_feeFilter);
                  pfrom->minFeeFilter = newFeeFilter;
              }
              LogPrint("net", "received: feefilter of %s from peer=%d\n", CFeeRate(newFeeFilter).ToString(), pfrom->id);
          }
      }
  
      else {
          // Ignore unknown commands for extensibility
          LogPrint("net", "Unknown command \"%s\" from peer=%d\n", SanitizeString(strCommand), pfrom->id);
      }
  
  
  
      return true;
  }
  
  // requires LOCK(cs_vRecvMsg)
  bool ProcessMessages(CNode* pfrom)
  {
      const CChainParams& chainparams = Params();
      //if (fDebug)
      //    LogPrintf("%s(%u messages)\n", __func__, pfrom->vRecvMsg.size());
  
      //
      // Message format
      //  (4) message start
      //  (12) command
      //  (4) size
      //  (4) checksum
      //  (x) data
      //
      bool fOk = true;
  
      if (!pfrom->vRecvGetData.empty())
          ProcessGetData(pfrom, chainparams.GetConsensus());
  
      // this maintains the order of responses
      if (!pfrom->vRecvGetData.empty()) return fOk;
  
      std::deque<CNetMessage>::iterator it = pfrom->vRecvMsg.begin();
      while (!pfrom->fDisconnect && it != pfrom->vRecvMsg.end()) {
          // Don't bother if send buffer is too full to respond anyway
          if (pfrom->nSendSize >= SendBufferSize())
              break;
  
          // get next message
          CNetMessage& msg = *it;
  
          //if (fDebug)
          //    LogPrintf("%s(message %u msgsz, %u bytes, complete:%s)\n", __func__,
          //            msg.hdr.nMessageSize, msg.vRecv.size(),
          //            msg.complete() ? "Y" : "N");
  
          // end, if an incomplete message is found
          if (!msg.complete())
              break;
  
          // at this point, any failure means we can delete the current message
          it++;
  
          // Scan for message start
          if (memcmp(msg.hdr.pchMessageStart, chainparams.MessageStart(), MESSAGE_START_SIZE) != 0) {
              LogPrintf("PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n", SanitizeString(msg.hdr.GetCommand()), pfrom->id);
              fOk = false;
              break;
          }
  
          // Read header
          CMessageHeader& hdr = msg.hdr;
          if (!hdr.IsValid(chainparams.MessageStart()))
          {
              LogPrintf("PROCESSMESSAGE: ERRORS IN HEADER %s peer=%d\n", SanitizeString(hdr.GetCommand()), pfrom->id);
              continue;
          }
          string strCommand = hdr.GetCommand();
  
          // Message size
          unsigned int nMessageSize = hdr.nMessageSize;
  
          // Checksum
          CDataStream& vRecv = msg.vRecv;
          uint256 hash = Hash(vRecv.begin(), vRecv.begin() + nMessageSize);
          unsigned int nChecksum = ReadLE32((unsigned char*)&hash);
          if (nChecksum != hdr.nChecksum)
          {
              LogPrintf("%s(%s, %u bytes): CHECKSUM ERROR nChecksum=%08x hdr.nChecksum=%08x\n", __func__,
                 SanitizeString(strCommand), nMessageSize, nChecksum, hdr.nChecksum);
              continue;
          }
  
          // Process message
          bool fRet = false;
          try
          {
              fRet = ProcessMessage(pfrom, strCommand, vRecv, msg.nTime, chainparams);
              boost::this_thread::interruption_point();
          }
          catch (const std::ios_base::failure& e)
          {
              pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_MALFORMED, string("error parsing message"));
              if (strstr(e.what(), "end of data"))
              {
                  // Allow exceptions from under-length message on vRecv
                  LogPrintf("%s(%s, %u bytes): Exception '%s' caught, normally caused by a message being shorter than its stated length\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
              }
              else if (strstr(e.what(), "size too large"))
              {
                  // Allow exceptions from over-long size
                  LogPrintf("%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
              }
              else if (strstr(e.what(), "non-canonical ReadCompactSize()"))
              {
                  // Allow exceptions from non-canonical encoding
                  LogPrintf("%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
              }
              else
              {
                  PrintExceptionContinue(&e, "ProcessMessages()");
              }
          }
          catch (const boost::thread_interrupted&) {
              throw;
          }
          catch (const std::exception& e) {
              PrintExceptionContinue(&e, "ProcessMessages()");
          } catch (...) {
              PrintExceptionContinue(NULL, "ProcessMessages()");
          }
  
          if (!fRet)
              LogPrintf("%s(%s, %u bytes) FAILED peer=%d\n", __func__, SanitizeString(strCommand), nMessageSize, pfrom->id);
  
          break;
      }
  
      // In case the connection got shut down, its receive buffer was wiped
      if (!pfrom->fDisconnect)
          pfrom->vRecvMsg.erase(pfrom->vRecvMsg.begin(), it);
  
      return fOk;
  }
  
  class CompareInvMempoolOrder
  {
      CTxMemPool *mp;
  public:
      CompareInvMempoolOrder(CTxMemPool *mempool)
      {
          mp = mempool;
      }
  
      bool operator()(std::set<uint256>::iterator a, std::set<uint256>::iterator b)
      {
          /* As std::make_heap produces a max-heap, we want the entries with the
           * fewest ancestors/highest fee to sort later. */
          return mp->CompareDepthAndScore(*b, *a);
      }
  };
  
  bool SendMessages(CNode* pto)
  {
      const Consensus::Params& consensusParams = Params().GetConsensus();
      {
          // Don't send anything until we get its version message
          if (pto->nVersion == 0)
              return true;
  
          //
          // Message: ping
          //
          bool pingSend = false;
          if (pto->fPingQueued) {
              // RPC ping request by user
              pingSend = true;
          }
          if (pto->nPingNonceSent == 0 && pto->nPingUsecStart + PING_INTERVAL * 1000000 < GetTimeMicros()) {
              // Ping automatically sent as a latency probe & keepalive.
              pingSend = true;
          }
          if (pingSend) {
              uint64_t nonce = 0;
              while (nonce == 0) {
                  GetRandBytes((unsigned char*)&nonce, sizeof(nonce));
              }
              pto->fPingQueued = false;
              pto->nPingUsecStart = GetTimeMicros();
              if (pto->nVersion > BIP0031_VERSION) {
                  pto->nPingNonceSent = nonce;
                  pto->PushMessage(NetMsgType::PING, nonce);
              } else {
                  // Peer is too old to support ping command with nonce, pong will never arrive.
                  pto->nPingNonceSent = 0;
                  pto->PushMessage(NetMsgType::PING);
              }
          }
  
          TRY_LOCK(cs_main, lockMain); // Acquire cs_main for IsInitialBlockDownload() and CNodeState()
          if (!lockMain)
              return true;
  
          // Address refresh broadcast
          int64_t nNow = GetTimeMicros();
          if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
              AdvertiseLocal(pto);
              pto->nNextLocalAddrSend = PoissonNextSend(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
          }
  
          //
          // Message: addr
          //
          if (pto->nNextAddrSend < nNow) {
              pto->nNextAddrSend = PoissonNextSend(nNow, AVG_ADDRESS_BROADCAST_INTERVAL);
              vector<CAddress> vAddr;
              vAddr.reserve(pto->vAddrToSend.size());
              BOOST_FOREACH(const CAddress& addr, pto->vAddrToSend)
              {
                  if (!pto->addrKnown.contains(addr.GetKey()))
                  {
                      pto->addrKnown.insert(addr.GetKey());
                      vAddr.push_back(addr);
                      // receiver rejects addr messages larger than 1000
                      if (vAddr.size() >= 1000)
                      {
                          pto->PushMessage(NetMsgType::ADDR, vAddr);
                          vAddr.clear();
                      }
                  }
              }
              pto->vAddrToSend.clear();
              if (!vAddr.empty())
                  pto->PushMessage(NetMsgType::ADDR, vAddr);
              // we only send the big addr message once
              if (pto->vAddrToSend.capacity() > 40)
                  pto->vAddrToSend.shrink_to_fit();
          }
  
          CNodeState &state = *State(pto->GetId());
          if (state.fShouldBan) {
              if (pto->fWhitelisted)
                  LogPrintf("Warning: not punishing whitelisted peer %s!\n", pto->addr.ToString());
              else {
                  pto->fDisconnect = true;
                  if (pto->addr.IsLocal())
                      LogPrintf("Warning: not banning local peer %s!\n", pto->addr.ToString());
                  else
                  {
                      CNode::Ban(pto->addr, BanReasonNodeMisbehaving);
                      // Remove all data from the header spam filter when the address is banned
                      CleanAddressHeaders(pto->addr);
                  }
              }
              state.fShouldBan = false;
          }
  
          BOOST_FOREACH(const CBlockReject& reject, state.rejects)
              pto->PushMessage(NetMsgType::REJECT, (string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock);
          state.rejects.clear();
  
          // Start block sync
          if (pindexBestHeader == NULL)
              pindexBestHeader = chainActive.Tip();
  
          bool fFetch = state.fPreferredDownload || (nPreferredDownload == 0 && !pto->fClient && !pto->fOneShot); // Download if this is a nice peer, or we have no nice peers and this one might do.
          if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) {
              // Only actively request headers from a single peer, unless we're close to today.
              if ((nSyncStarted == 0 && fFetch) || pindexBestHeader->GetBlockTime() > GetAdjustedTime() - 24 * 60 * 60) {
                  state.fSyncStarted = true;
                  nSyncStarted++;
                  const CBlockIndex *pindexStart = pindexBestHeader;
                  /* If possible, start at the block preceding the currently
                     best known header.  This ensures that we always get a
                     non-empty list of headers back as long as the peer
                     is up-to-date.  With a non-empty response, we can initialise
                     the peer's known best block.  This wouldn't be possible
                     if we requested starting at pindexBestHeader and
                     got back an empty response.  */
                  if (pindexStart->pprev)
                      pindexStart = pindexStart->pprev;
                  LogPrint("net", "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->id, pto->nStartingHeight);
                  pto->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexStart), uint256());
              }
          }
  
          // Resend wallet transactions that haven't gotten in a block yet
          // Except during reindex, importing and IBD, when old wallet
          // transactions become unconfirmed and spams other nodes.
          if (!fReindex && !fImporting && !IsInitialBlockDownload())
          {
              GetMainSignals().Broadcast(nTimeBestReceived);
          }
  
          //
          // Try sending block announcements via headers
          //
          {
              // If we have less than MAX_BLOCKS_TO_ANNOUNCE in our
              // list of block hashes we're relaying, and our peer wants
              // headers announcements, then find the first header
              // not yet known to our peer but would connect, and send.
              // If no header would connect, or if we have too many
              // blocks, or if the peer doesn't want headers, just
              // add all to the inv queue.
              LOCK(pto->cs_inventory);
              vector<CBlock> vHeaders;
              bool fRevertToInv = ((!state.fPreferHeaders &&
                                   (!state.fPreferHeaderAndIDs || pto->vBlockHashesToAnnounce.size() > 1)) ||
                                  pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE);
              CBlockIndex *pBestIndex = NULL; // last header queued for delivery
              ProcessBlockAvailability(pto->id); // ensure pindexBestKnownBlock is up-to-date
  
              if (!fRevertToInv) {
                  bool fFoundStartingHeader = false;
                  // Try to find first header that our peer doesn't have, and
                  // then send all headers past that one.  If we come across any
                  // headers that aren't on chainActive, give up.
                  BOOST_FOREACH(const uint256 &hash, pto->vBlockHashesToAnnounce) {
                      BlockMap::iterator mi = mapBlockIndex.find(hash);
                      assert(mi != mapBlockIndex.end());
                      CBlockIndex *pindex = mi->second;
                      if (chainActive[pindex->nHeight] != pindex) {
                          // Bail out if we reorged away from this block
                          fRevertToInv = true;
                          break;
                      }
                      if (pBestIndex != NULL && pindex->pprev != pBestIndex) {
                          // This means that the list of blocks to announce don't
                          // connect to each other.
                          // This shouldn't really be possible to hit during
                          // regular operation (because reorgs should take us to
                          // a chain that has some block not on the prior chain,
                          // which should be caught by the prior check), but one
                          // way this could happen is by using invalidateblock /
                          // reconsiderblock repeatedly on the tip, causing it to
                          // be added multiple times to vBlockHashesToAnnounce.
                          // Robustly deal with this rare situation by reverting
                          // to an inv.
                          fRevertToInv = true;
                          break;
                      }
                      pBestIndex = pindex;
                      if (fFoundStartingHeader) {
                          // add this to the headers message
                          vHeaders.push_back(pindex->GetBlockHeader());
                      } else if (PeerHasHeader(&state, pindex)) {
                          continue; // keep looking for the first new block
                      } else if (pindex->pprev == NULL || PeerHasHeader(&state, pindex->pprev)) {
                          // Peer doesn't have this header but they do have the prior one.
                          // Start sending headers.
                          fFoundStartingHeader = true;
                          vHeaders.push_back(pindex->GetBlockHeader());
                      } else {
                          // Peer doesn't have this header or the prior one -- nothing will
                          // connect, so bail out.
                          fRevertToInv = true;
                          break;
                      }
                  }
              }
              if (!fRevertToInv && !vHeaders.empty()) {
                  if (vHeaders.size() == 1 && state.fPreferHeaderAndIDs) {
                      // We only send up to 1 block as header-and-ids, as otherwise
                      // probably means we're doing an initial-ish-sync or they're slow
                      LogPrint("net", "%s sending header-and-ids %s to peer %d\n", __func__,
                              vHeaders.front().GetHash().ToString(), pto->id);
                      //TODO: Shouldn't need to reload block from disk, but requires refactor
                      CBlock block;
                      assert(ReadBlockFromDisk(block, pBestIndex, consensusParams));
                      CBlockHeaderAndShortTxIDs cmpctblock(block);
                      pto->PushMessageWithFlag(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::CMPCTBLOCK, cmpctblock);
                      state.pindexBestHeaderSent = pBestIndex;
                  } else if (state.fPreferHeaders) {
                      if (vHeaders.size() > 1) {
                          LogPrint("net", "%s: %u headers, range (%s, %s), to peer=%d\n", __func__,
                                  vHeaders.size(),
                                  vHeaders.front().GetHash().ToString(),
                                  vHeaders.back().GetHash().ToString(), pto->id);
                      } else {
                          LogPrint("net", "%s: sending header %s to peer=%d\n", __func__,
                                  vHeaders.front().GetHash().ToString(), pto->id);
                      }
                      pto->PushMessage(NetMsgType::HEADERS, vHeaders);
                      state.pindexBestHeaderSent = pBestIndex;
                  } else
                      fRevertToInv = true;
              }
              if (fRevertToInv) {
                  // If falling back to using an inv, just try to inv the tip.
                  // The last entry in vBlockHashesToAnnounce was our tip at some point
                  // in the past.
                  if (!pto->vBlockHashesToAnnounce.empty()) {
                      const uint256 &hashToAnnounce = pto->vBlockHashesToAnnounce.back();
                      BlockMap::iterator mi = mapBlockIndex.find(hashToAnnounce);
                      assert(mi != mapBlockIndex.end());
                      CBlockIndex *pindex = mi->second;
  
                      // Warn if we're announcing a block that is not on the main chain.
                      // This should be very rare and could be optimized out.
                      // Just log for now.
                      if (chainActive[pindex->nHeight] != pindex) {
                          LogPrint("net", "Announcing block %s not on main chain (tip=%s)\n",
                              hashToAnnounce.ToString(), chainActive.Tip()->GetBlockHash().ToString());
                      }
  
                      // If the peer's chain has this block, don't inv it back.
                      if (!PeerHasHeader(&state, pindex)) {
                          pto->PushInventory(CInv(MSG_BLOCK, hashToAnnounce));
                          LogPrint("net", "%s: sending inv peer=%d hash=%s\n", __func__,
                              pto->id, hashToAnnounce.ToString());
                      }
                  }
              }
              pto->vBlockHashesToAnnounce.clear();
          }
  
          //
          // Message: inventory
          //
          vector<CInv> vInv;
          {
              LOCK(pto->cs_inventory);
              vInv.reserve(std::max<size_t>(pto->vInventoryBlockToSend.size(), INVENTORY_BROADCAST_MAX));
  
              // Add blocks
              BOOST_FOREACH(const uint256& hash, pto->vInventoryBlockToSend) {
                  vInv.push_back(CInv(MSG_BLOCK, hash));
                  if (vInv.size() == MAX_INV_SZ) {
                      pto->PushMessage(NetMsgType::INV, vInv);
                      vInv.clear();
                  }
              }
              pto->vInventoryBlockToSend.clear();
  
              // Check whether periodic sends should happen
              bool fSendTrickle = pto->fWhitelisted;
              if (pto->nNextInvSend < nNow) {
                  fSendTrickle = true;
                  // Use half the delay for outbound peers, as there is less privacy concern for them.
                  pto->nNextInvSend = PoissonNextSend(nNow, INVENTORY_BROADCAST_INTERVAL >> !pto->fInbound);
              }
  
              // Time to send but the peer has requested we not relay transactions.
              if (fSendTrickle) {
                  LOCK(pto->cs_filter);
                  if (!pto->fRelayTxes) pto->setInventoryTxToSend.clear();
              }
  
              // Respond to BIP35 mempool requests
              if (fSendTrickle && pto->fSendMempool) {
                  auto vtxinfo = mempool.infoAll();
                  pto->fSendMempool = false;
                  CAmount filterrate = 0;
                  {
                      LOCK(pto->cs_feeFilter);
                      filterrate = pto->minFeeFilter;
                  }
  
                  LOCK(pto->cs_filter);
  
                  for (const auto& txinfo : vtxinfo) {
                      const uint256& hash = txinfo.tx->GetHash();
                      CInv inv(MSG_TX, hash);
                      pto->setInventoryTxToSend.erase(hash);
                      if (filterrate) {
                          if (txinfo.feeRate.GetFeePerK() < filterrate)
                              continue;
                      }
                      if (pto->pfilter) {
                          if (!pto->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue;
                      }
                      pto->filterInventoryKnown.insert(hash);
                      vInv.push_back(inv);
                      if (vInv.size() == MAX_INV_SZ) {
                          pto->PushMessage(NetMsgType::INV, vInv);
                          vInv.clear();
                      }
                  }
                  pto->timeLastMempoolReq = GetTime();
              }
  
              // Determine transactions to relay
              if (fSendTrickle) {
                  // Produce a vector with all candidates for sending
                  vector<std::set<uint256>::iterator> vInvTx;
                  vInvTx.reserve(pto->setInventoryTxToSend.size());
                  for (std::set<uint256>::iterator it = pto->setInventoryTxToSend.begin(); it != pto->setInventoryTxToSend.end(); it++) {
                      vInvTx.push_back(it);
                  }
                  CAmount filterrate = 0;
                  {
                      LOCK(pto->cs_feeFilter);
                      filterrate = pto->minFeeFilter;
                  }
                  // Topologically and fee-rate sort the inventory we send for privacy and priority reasons.
                  // A heap is used so that not all items need sorting if only a few are being sent.
                  CompareInvMempoolOrder compareInvMempoolOrder(&mempool);
                  std::make_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder);
                  // No reason to drain out at many times the network's capacity,
                  // especially since we have many peers and some will draw much shorter delays.
                  unsigned int nRelayedTransactions = 0;
                  LOCK(pto->cs_filter);
                  while (!vInvTx.empty() && nRelayedTransactions < INVENTORY_BROADCAST_MAX) {
                      // Fetch the top element from the heap
                      std::pop_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder);
                      std::set<uint256>::iterator it = vInvTx.back();
                      vInvTx.pop_back();
                      uint256 hash = *it;
                      // Remove it from the to-be-sent set
                      pto->setInventoryTxToSend.erase(it);
                      // Check if not in the filter already
                      if (pto->filterInventoryKnown.contains(hash)) {
                          continue;
                      }
                      // Not in the mempool anymore? don't bother sending it.
                      auto txinfo = mempool.info(hash);
                      if (!txinfo.tx) {
                          continue;
                      }
                      if (filterrate && txinfo.feeRate.GetFeePerK() < filterrate) {
                          continue;
                      }
                      if (pto->pfilter && !pto->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue;
                      // Send
                      vInv.push_back(CInv(MSG_TX, hash));
                      nRelayedTransactions++;
                      {
                          // Expire old relay messages
                          while (!vRelayExpiration.empty() && vRelayExpiration.front().first < nNow)
                          {
                              mapRelay.erase(vRelayExpiration.front().second);
                              vRelayExpiration.pop_front();
                          }
  
                          auto ret = mapRelay.insert(std::make_pair(hash, std::move(txinfo.tx)));
                          if (ret.second) {
                              vRelayExpiration.push_back(std::make_pair(nNow + 15 * 60 * 1000000, ret.first));
                          }
                      }
                      if (vInv.size() == MAX_INV_SZ) {
                          pto->PushMessage(NetMsgType::INV, vInv);
                          vInv.clear();
                      }
                      pto->filterInventoryKnown.insert(hash);
                  }
              }
          }
          if (!vInv.empty())
              pto->PushMessage(NetMsgType::INV, vInv);
  
          // Detect whether we're stalling
          nNow = GetTimeMicros();
          if (!pto->fDisconnect && state.nStallingSince && state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
              // Stalling only triggers when the block download window cannot move. During normal steady state,
              // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection
              // should only happen during initial block download.
              LogPrintf("Peer=%d is stalling block download, disconnecting\n", pto->id);
              pto->fDisconnect = true;
          }
          // In case there is a block that has been in flight from this peer for 2 + 0.5 * N times the block interval
          // (with N the number of peers from which we're downloading validated blocks), disconnect due to timeout.
          // We compensate for other peers to prevent killing off peers due to our own downstream link
          // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes
          // to unreasonably increase our timeout.
          if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0) {
              QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
              int nOtherPeersWithValidatedDownloads = nPeersWithValidatedDownloads - (state.nBlocksInFlightValidHeaders > 0);
              if (nNow > state.nDownloadingSince + consensusParams.nPowTargetSpacing * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) {
                  LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", queuedBlock.hash.ToString(), pto->id);
                  pto->fDisconnect = true;
              }
          }
  
          //
          // Message: getdata (blocks)
          //
          vector<CInv> vGetData;
  
  
          if (!pto->fDisconnect && !pto->fClient && (fFetch || !IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
              vector<CBlockIndex*> vToDownload;
              NodeId staller = -1;
  
              FindNextBlocksToDownload(pto->GetId(), MAX_BLOCKS_IN_TRANSIT_PER_PEER - state.nBlocksInFlight, vToDownload, staller);
              BOOST_FOREACH(CBlockIndex *pindex, vToDownload) {
                  if (State(pto->GetId())->fHaveWitness || !IsWitnessEnabled(pindex->pprev, consensusParams)) {
                      uint32_t nFetchFlags = GetFetchFlags(pto, pindex->pprev, consensusParams);
                      vGetData.push_back(CInv(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash()));
                      MarkBlockAsInFlight(pto->GetId(), pindex->GetBlockHash(), consensusParams, pindex);
                      LogPrint("net", "Requesting block %s (%d) peer=%d\n", pindex->GetBlockHash().ToString(),
                          pindex->nHeight, pto->id);
                  }
              }
              if (state.nBlocksInFlight == 0 && staller != -1  && State(pto->GetId())->fHaveWitness) {
                  if (State(staller)->nStallingSince == 0) {
                      State(staller)->nStallingSince = nNow;
                      LogPrint("net", "Stall started peer=%d\n", staller);
                  }
              }
          }
  
          //
          // Message: getdata (non-blocks)
          //
          while (!pto->fDisconnect && !pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
          {
              const CInv& inv = (*pto->mapAskFor.begin()).second;
              if (!AlreadyHave(inv))
              {
                  if (fDebug)
                      LogPrint("net", "Requesting %s peer=%d\n", inv.ToString(), pto->id);
                  vGetData.push_back(inv);
                  if (vGetData.size() >= 1000)
                  {
                      pto->PushMessage(NetMsgType::GETDATA, vGetData);
                      vGetData.clear();
                  }
              } else {
                  //If we're not going to ask, don't expect a response.
                  pto->setAskFor.erase(inv.hash);
              }
              pto->mapAskFor.erase(pto->mapAskFor.begin());
          }
          if (!vGetData.empty())
              pto->PushMessage(NetMsgType::GETDATA, vGetData);
  
          //
          // Message: feefilter
          //
          // We don't want white listed peers to filter txs to us if we have -whitelistforcerelay
          if (pto->nVersion >= FEEFILTER_VERSION && GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
              !(pto->fWhitelisted && GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY))) {
              CAmount currentFilter = mempool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK();
              int64_t timeNow = GetTimeMicros();
              if (timeNow > pto->nextSendTimeFeeFilter) {
                  CAmount filterToSend = filterRounder.round(currentFilter);
                  if (filterToSend != pto->lastSentFeeFilter) {
                      pto->PushMessage(NetMsgType::FEEFILTER, filterToSend);
                      pto->lastSentFeeFilter = filterToSend;
                  }
                  pto->nextSendTimeFeeFilter = PoissonNextSend(timeNow, AVG_FEEFILTER_BROADCAST_INTERVAL);
              }
              // If the fee filter has changed substantially and it's still more than MAX_FEEFILTER_CHANGE_DELAY
              // until scheduled broadcast, then move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY.
              else if (timeNow + MAX_FEEFILTER_CHANGE_DELAY * 1000000 < pto->nextSendTimeFeeFilter &&
                       (currentFilter < 3 * pto->lastSentFeeFilter / 4 || currentFilter > 4 * pto->lastSentFeeFilter / 3)) {
                  pto->nextSendTimeFeeFilter = timeNow + (insecure_rand() % MAX_FEEFILTER_CHANGE_DELAY) * 1000000;
              }
          }
      }
      return true;
  }
  
   std::string CBlockFileInfo::ToString() const {
       return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
   }
  
  ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos)
  {
      LOCK(cs_main);
      return VersionBitsState(chainActive.Tip(), params, pos, versionbitscache);
  }
  
  class CMainCleanup
  {
  public:
      CMainCleanup() {}
      ~CMainCleanup() {
          // block headers
          BlockMap::iterator it1 = mapBlockIndex.begin();
          for (; it1 != mapBlockIndex.end(); it1++)
              delete (*it1).second;
          mapBlockIndex.clear();
  
          // orphan transactions
          mapOrphanTransactions.clear();
          mapOrphanTransactionsByPrev.clear();
      }
  } instance_of_cmaincleanup;
  
  // ppcoin: find last block index up to pindex
  const CBlockIndex* GetLastBlockIndex(const CBlockIndex* pindex, bool fProofOfStake)
  {
      while (pindex && pindex->pprev && (pindex->IsProofOfStake() != fProofOfStake))
          pindex = pindex->pprev;
      return pindex;
  }
  
  unsigned int ComputedMinStake(unsigned int nBase, int64_t nTime, unsigned int nBlockTime)
  {
    return ComputeMaxBits(bnProofOfStakeLimit, nBase, nTime);
  }
  
  unsigned int GetNextTargetRequired(const CBlockIndex* pindexLast, bool fProofOfStake)
  {
  
      arith_uint256 bnTargetLimit = fProofOfStake ? GetProofOfStakeLimit(pindexLast->nHeight) : Params().ProofOfWorkLimit();
  
      if (pindexLast == NULL)
          return bnTargetLimit.GetCompact(); // genesis block
  
  
      const CBlockIndex* pindexPrev = GetLastBlockIndex(pindexLast, fProofOfStake);
      if (pindexPrev->pprev == NULL)
          return bnTargetLimit.GetCompact(); // first block
  
      const CBlockIndex* pindexPrevPrev = GetLastBlockIndex(pindexPrev->pprev, fProofOfStake);
      if (pindexPrevPrev->pprev == NULL)
          return bnTargetLimit.GetCompact(); // second block
  
      int64_t nActualSpacing = pindexPrev->GetBlockTime() - pindexPrevPrev->GetBlockTime();
  
      if (nActualSpacing < 0)
          nActualSpacing = Params().GetConsensus().nTargetSpacing;
  
      // ppcoin: target change every block
      // ppcoin: retarget with exponential moving toward target spacing
      arith_uint256 bnNew;
      bnNew.SetCompact(pindexPrev->nBits);
  
      arith_uint256 nInterval = (Params().GetConsensus().nTargetTimespan) / (Params().GetConsensus().nTargetSpacing);
      bnNew *= (((nInterval - 1)) * (Params().GetConsensus().nTargetSpacing) + (nActualSpacing) + (nActualSpacing));
      bnNew /= (((nInterval + 1)) * (Params().GetConsensus().nTargetSpacing));
  
      if (bnNew <= 0 || bnNew > bnTargetLimit)
          bnNew = bnTargetLimit;
  
      return bnNew.GetCompact();
  }
  
  arith_uint256 GetProofOfStakeLimit(int nHeight)
  {
      return (bnProofOfStakeLimitV2);
  }
  
  bool TransactionGetCoinAge(CTransaction& transaction, uint64_t& nCoinAge)
  {
      arith_uint256 bnCentSecond = 0;  // coin age in the unit of cent-seconds
      nCoinAge = 0;
  
      if (transaction.IsCoinBase())
          return true;
  
      BOOST_FOREACH(const CTxIn& txin, transaction.vin)
      {
          // First try finding the previous transaction in database
          CTransaction txPrev;
          uint256 hashBlock = uint256();
  
          if (!GetTransaction(txin.prevout.hash, txPrev, Params().GetConsensus(), hashBlock, true))
              continue;  // previous transaction not in main chain
  
          if (transaction.nTime < txPrev.nTime)
              return false;  // Transaction timestamp violation
  
          if (mapBlockIndex.count(hashBlock) == 0)
              return false; //Block not found
  
          CBlockIndex* pblockindex = mapBlockIndex[hashBlock];
  
          if (pblockindex->nTime + Params().GetConsensus().nStakeMinAge > transaction.nTime)
              continue; // only count coins meeting min age requirement
  
          int64_t nValueIn = txPrev.vout[txin.prevout.n].nValue;
          bnCentSecond += arith_uint256(nValueIn) * (transaction.nTime-txPrev.nTime) / CENT;
  
  
          LogPrint("coinage", "coin age nValueIn=%d nTimeDiff=%d bnCentSecond=%s\n", nValueIn, transaction.nTime - txPrev.nTime, bnCentSecond.ToString());
      }
  
  
      arith_uint256 bnCoinDay = ((bnCentSecond * CENT) / COIN) / (24 * 60 * 60);
      LogPrint("coinage", "coin age bnCoinDay=%s\n", bnCoinDay.ToString());
      nCoinAge = bnCoinDay.GetLow64();
  
      return true;
  }
  
  using namespace std;
  
  // Get time weight
  int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd)
  {
      // Kernel hash weight starts from 0 at the min age
      // this change increases active coins participating the hash and helps
      // to secure the network when proof-of-stake difficulty is low
  
      return nIntervalEnd - nIntervalBeginning - Params().GetConsensus().nStakeMinAge;
  }
  
  // Get the last stake modifier and its generation time from a given block
  static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64_t& nStakeModifier, int64_t& nModifierTime)
  {
      if (!pindex)
          return error("GetLastStakeModifier: null pindex");
      while (pindex && pindex->pprev && !pindex->GeneratedStakeModifier())
          pindex = pindex->pprev;
      if (!pindex->GeneratedStakeModifier()){
          nStakeModifier = 1;
          nModifierTime = pindex->GetBlockTime();
          return true;
      }
      nStakeModifier = pindex->nStakeModifier;
      nModifierTime = pindex->GetBlockTime();
      return true;
  }
  
  // Get selection interval section (in seconds)
  static int64_t GetStakeModifierSelectionIntervalSection(int nSection)
  {
      assert (nSection >= 0 && nSection < 64);
      return (Params().GetConsensus().nModifierInterval * 63 / (63 + ((63 - nSection) * (MODIFIER_INTERVAL_RATIO - 1))));
  }
  
  // Get stake modifier selection interval (in seconds)
  static int64_t GetStakeModifierSelectionInterval()
  {
      int64_t nSelectionInterval = 0;
      for (int nSection=0; nSection<64; nSection++)
          nSelectionInterval += GetStakeModifierSelectionIntervalSection(nSection);
      return nSelectionInterval;
  }
  
  // select a block from the candidate blocks in vSortedByTimestamp, excluding
  // already selected blocks in vSelectedBlocks, and with timestamp up to
  // nSelectionIntervalStop.
  static bool SelectBlockFromCandidates(vector<pair<int64_t, uint256> >& vSortedByTimestamp, map<uint256, const CBlockIndex*>& mapSelectedBlocks,
      int64_t nSelectionIntervalStop, uint64_t nStakeModifierPrev, const CBlockIndex** pindexSelected)
  {
      bool fSelected = false;
      uint256 hashBest = uint256();
      *pindexSelected = (const CBlockIndex*) 0;
      BOOST_FOREACH(const PAIRTYPE(int64_t, uint256)& item, vSortedByTimestamp)
      {
          if (!mapBlockIndex.count(item.second))
              return error("SelectBlockFromCandidates: failed to find block index for candidate block %s", item.second.ToString());
          const CBlockIndex* pindex = mapBlockIndex[item.second];
          if (fSelected && pindex->GetBlockTime() > nSelectionIntervalStop){
  //            LogPrint("stakemodifier", "SelectBlockFromCandidates: selection hash=%s index=%d proofhash=%s nStakeModifierPrev=%08x\n", hashBest.ToString(), pindex->nHeight, pindex->hashProof.ToString(), nStakeModifierPrev);
              break;
  
          }
  
          if (mapSelectedBlocks.count(pindex->GetBlockHash()) > 0)
              continue;
          // compute the selection hash by hashing its proof-hash and the
          // previous proof-of-stake modifier
          CDataStream ss(SER_GETHASH, 0);
          ss << ArithToUint256(pindex->hashProof) << nStakeModifierPrev;
          uint256 hashSelection = Hash(ss.begin(), ss.end());
  
  
          // the selection hash is divided by 2**32 so that proof-of-stake block
          // is always favored over proof-of-work block. this is to preserve
          // the energy efficiency property
          if (pindex->IsProofOfStake())
              hashSelection = ArithToUint256(UintToArith256(hashSelection) >> 32);
  
          if (fSelected && hashSelection < hashBest)
          {
              hashBest = hashSelection;
              *pindexSelected = (const CBlockIndex*) pindex;
          }
          else if (!fSelected)
          {
              fSelected = true;
              hashBest = hashSelection;
              *pindexSelected = (const CBlockIndex*) pindex;
          }
      }
      return fSelected;
  }
  
  // Stake Modifier (hash modifier of proof-of-stake):
  // The purpose of stake modifier is to prevent a txout (coin) owner from
  // computing future proof-of-stake generated by this txout at the time
  // of transaction confirmation. To meet kernel protocol, the txout
  // must hash with a future stake modifier to generate the proof.
  // Stake modifier consists of bits each of which is contributed from a
  // selected block of a given block group in the past.
  // The selection of a block is based on a hash of the block's proof-hash and
  // the previous stake modifier.
  // Stake modifier is recomputed at a fixed time interval instead of every
  // block. This is to make it difficult for an attacker to gain control of
  // additional bits in the stake modifier, even after generating a chain of
  // blocks.
  bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier)
  {
      nStakeModifier = 0;
      fGeneratedStakeModifier = false;
      if (!pindexPrev)
      {
          fGeneratedStakeModifier = true;
          return error("ComputeNextStakeModifier(): Could not find pindexPrev");  // genesis block's modifier is 0
      }
      // First find current stake modifier and its generation block time
      // if it's not old enough, return the same stake modifier
      int64_t nModifierTime = 0;
      if (!GetLastStakeModifier(pindexPrev, nStakeModifier, nModifierTime))
          return error("ComputeNextStakeModifier: unable to get last modifier");
  //    LogPrint("stakemodifier", "ComputeNextStakeModifier: prev modifier=0x%016x time=%s\n", nStakeModifier, DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nModifierTime));
      if (nModifierTime / Params().GetConsensus().nModifierInterval >= pindexPrev->GetBlockTime() / Params().GetConsensus().nModifierInterval)
          return true;
  
      // Sort candidate blocks by timestamp
      vector<pair<int64_t, uint256> > vSortedByTimestamp;
      vSortedByTimestamp.reserve(64 * Params().GetConsensus().nModifierInterval / GetTargetSpacing(pindexPrev->nHeight));
      int64_t nSelectionInterval = GetStakeModifierSelectionInterval();
      int64_t nSelectionIntervalStart = (pindexPrev->GetBlockTime() / Params().GetConsensus().nModifierInterval)
              * Params().GetConsensus().nModifierInterval - nSelectionInterval;
  //    LogPrint("stakemodifier", "nSelectionInterval = %d nSelectionIntervalStart = %d\n",nSelectionInterval,nSelectionIntervalStart);
  
      const CBlockIndex* pindex = pindexPrev;
      while (pindex && pindex->GetBlockTime() >= nSelectionIntervalStart)
      {
          vSortedByTimestamp.push_back(make_pair(pindex->GetBlockTime(), pindex->GetBlockHash()));
          pindex = pindex->pprev;
      }
      int nHeightFirstCandidate = pindex ? (pindex->nHeight + 1) : 0;
      reverse(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
      sort(vSortedByTimestamp.begin(), vSortedByTimestamp.end());
  
      // Select 64 blocks from candidate blocks to generate stake modifier
      uint64_t nStakeModifierNew = 0;
      int64_t nSelectionIntervalStop = nSelectionIntervalStart;
      map<uint256, const CBlockIndex*> mapSelectedBlocks;
      for (int nRound=0; nRound<min(64, (int)vSortedByTimestamp.size()); nRound++)
      {
          // add an interval section to the current selection round
          nSelectionIntervalStop += GetStakeModifierSelectionIntervalSection(nRound);
          // select a block from the candidates of current round
          if (!SelectBlockFromCandidates(vSortedByTimestamp, mapSelectedBlocks, nSelectionIntervalStop, nStakeModifier, &pindex))
              return error("ComputeNextStakeModifier: unable to select block at round %d", nRound);
          // write the entropy bit of the selected block
          nStakeModifierNew |= (((uint64_t)pindex->GetStakeEntropyBit()) << nRound);
          // add the selected block from candidates to selected list
          mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex));
  //        LogPrint("stakemodifier", "ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nSelectionIntervalStop), pindex->nHeight, pindex->GetStakeEntropyBit());
      }
  
      // Print selection map for visualization of the selected blocks
      if (LogAcceptCategory("stakemodifier"))
      {
          string strSelectionMap = "";
          // '-' indicates proof-of-work blocks not selected
          strSelectionMap.insert(0, pindexPrev->nHeight - nHeightFirstCandidate + 1, '-');
          pindex = pindexPrev;
          while (pindex && pindex->nHeight >= nHeightFirstCandidate)
          {
              // '=' indicates proof-of-stake blocks not selected
              if (pindex->IsProofOfStake())
                  strSelectionMap.replace(pindex->nHeight - nHeightFirstCandidate, 1, "=");
              pindex = pindex->pprev;
          }
          BOOST_FOREACH(const PAIRTYPE(uint256, const CBlockIndex*)& item, mapSelectedBlocks)
          {
              // 'S' indicates selected proof-of-stake blocks
              // 'W' indicates selected proof-of-work blocks
              strSelectionMap.replace(item.second->nHeight - nHeightFirstCandidate, 1, item.second->IsProofOfStake()? "S" : "W");
          }
  //        LogPrintf("ComputeNextStakeModifier: selection height [%d, %d] map %s\n", nHeightFirstCandidate, pindexPrev->nHeight, strSelectionMap);
      }
  //    LogPrint("stakemodifier", "ComputeNextStakeModifier: new modifier=0x%016x time=%s\n", nStakeModifierNew, DateTimeStrFormat("%Y-%m-%d %H:%M:%S", pindexPrev->GetBlockTime()));
  
      nStakeModifier = nStakeModifierNew;
      fGeneratedStakeModifier = true;
      return true;
  }
  
  
  static bool CheckStakeKernelHashV2(CBlockIndex* pindexPrev, unsigned int nBits, unsigned int nTimeBlockFrom, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, arith_uint256& hashProofOfStake, arith_uint256& targetProofOfStake, bool fPrintProofOfStake)
  {
  
      if (nTimeTx < txPrev.nTime)  // Transaction timestamp violation
          return error("CheckStakeKernelHash() : nTime violation");
  
  
      if (nTimeBlockFrom + Params().GetConsensus().nStakeMinAge > nTimeTx) // Min age requirement
          return error("CheckStakeKernelHash() : min age violation");
  
      // Base target
      targetProofOfStake.SetCompact(nBits);
  
      // Weighted target
      int64_t nValueIn = txPrev.vout[prevout.n].nValue;
      arith_uint512 bnWeight = arith_uint512(nValueIn);
  
      // We need to convert to uint512 to prevent overflow when multiplying by 1st block coins
      base_uint<512> targetProofOfStake512(targetProofOfStake.GetHex());
      targetProofOfStake512 *= bnWeight;
  
      uint64_t nStakeModifier = pindexPrev->nStakeModifier;
      int nStakeModifierHeight = pindexPrev->nHeight;
      int64_t nStakeModifierTime = pindexPrev->nTime;
  
      // Calculate hash
      CDataStream ss(SER_GETHASH, 0);
      ss << nStakeModifier << nTimeBlockFrom << txPrev.nTime << prevout.hash << prevout.n << nTimeTx;
      hashProofOfStake = UintToArith256(Hash(ss.begin(), ss.end()));
  
      if (fPrintProofOfStake)
      {
          LogPrint("stakemodifier","CheckStakeKernelHash() : using modifier 0x%016x at height=%d timestamp=%s for block from timestamp=%s\n",
              nStakeModifier, nStakeModifierHeight,
              DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nStakeModifierTime),
              DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nTimeBlockFrom));
          LogPrint("stakemodifier","CheckStakeKernelHash() : check modifier=0x%016x nTimeBlockFrom=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s bnTarget=%s nBits=%08x nValueIn=%d bnWeight=%s\n",
              nStakeModifier,
              nTimeBlockFrom, txPrev.nTime, prevout.n, nTimeTx,
              hashProofOfStake.ToString(), targetProofOfStake512.ToString(), nBits, nValueIn,bnWeight.ToString());
      }
  
      // We need to convert type so it can be compared to target
      base_uint<512> hashProofOfStake512(hashProofOfStake.GetHex());
  
      // Now check if proof-of-stake hash meets target protocol
      if (hashProofOfStake512 > targetProofOfStake512)
        return false;
  
      if (fDebug && !fPrintProofOfStake)
      {
          LogPrint("stakemodifier","CheckStakeKernelHash() : using modifier 0x%016x at height=%d timestamp=%s for block from timestamp=%s\n",
              nStakeModifier, nStakeModifierHeight,
              DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nStakeModifierTime),
              DateTimeStrFormat("%Y-%m-%d %H:%M:%S", nTimeBlockFrom));
          LogPrint("stakemodifier","CheckStakeKernelHash() : pass modifier=0x%016x nTimeBlockFrom=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n",
              nStakeModifier,
              nTimeBlockFrom, txPrev.nTime, prevout.n, nTimeTx,
              hashProofOfStake.ToString());
      }
  
      return true;
  }
  
  bool CheckStakeKernelHash(CBlockIndex* pindexPrev, unsigned int nBits, CBlockIndex& blockFrom, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, arith_uint256& hashProofOfStake, arith_uint256& targetProofOfStake, bool fPrintProofOfStake)
  {
      // if (IsProtocolV2(pindexPrev->nHeight+1))
          return CheckStakeKernelHashV2(pindexPrev, nBits, blockFrom.GetBlockTime(), txPrev, prevout, nTimeTx, hashProofOfStake, targetProofOfStake, true);
      // else
          // return CheckStakeKernelHashV1(nBits, blockFrom, nTxPrevOffset, txPrev, prevout, nTimeTx, hashProofOfStake, targetProofOfStake, fPrintProofOfStake);
  }
  
  //Check kernel hash target and coinstake signature
  bool CheckProofOfStake(CBlockIndex* pindexPrev, const CTransaction& tx, unsigned int nBits, arith_uint256& hashProofOfStake, arith_uint256& targetProofOfStake, std::vector<CScriptCheck> *pvChecks, bool fCHeckSignature)
  {
      if (!tx.IsCoinStake())
          return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString());
  
      // Kernel (input 0) must match the stake hash target per coin age (nBits)
      const CTxIn& txin = tx.vin[0];
  
      CTransaction txPrev;
      uint256 hashBlock = uint256();
      if (!GetTransaction(txin.prevout.hash, txPrev, Params().GetConsensus(), hashBlock, true))
          return error("CheckProofOfStake() : INFO: read txPrev failed %s",txin.prevout.hash.GetHex());  // previous transaction not in main chain, may occur during initial download
  
      if (txPrev.vout[txin.prevout.n].scriptPubKey.IsColdStaking())
          for(unsigned int i = 1; i < tx.vout.size() - 1; i++) // First output is empty, last is CFund contribution
              if(tx.vout[i].scriptPubKey != txPrev.vout[txin.prevout.n].scriptPubKey)
                  return error(strprintf("CheckProofOfStake(): Coinstake output %d tried to move cold staking coins to a non authorised script. (%s vs. %s)",
                                         i, ScriptToAsmStr(txPrev.vout[txin.prevout.n].scriptPubKey), ScriptToAsmStr(tx.vout[i].scriptPubKey)));
  
      if (pvChecks)
          pvChecks->reserve(tx.vin.size());
  
      CCoinsViewCache inputs(pcoinsTip);
  
      if(fCHeckSignature)
      {
          PrecomputedTransactionData txdata(tx);
          const COutPoint &prevout = tx.vin[0].prevout;
          const CCoins* coins = inputs.AccessCoins(prevout.hash);
          assert(coins);
  
          // Verify signature
          CScriptCheck check(*coins, tx, 0, SCRIPT_VERIFY_NONE, false, &txdata);
          if (pvChecks) {
              pvChecks->push_back(CScriptCheck());
              check.swap(pvChecks->back());
          } else if (!check())
              return error("CheckProofOfStake() : script-verify-failed %s",ScriptErrorString(check.GetScriptError()));
      }
  
      if (mapBlockIndex.count(hashBlock) == 0)
          return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
  
      CBlockIndex* pblockindex = mapBlockIndex[hashBlock];
  
      if (txin.prevout.hash != txPrev.GetHash())
          return error("CheckProofOfStake(): Coinstake input does not match previous output %s",txin.prevout.hash.GetHex());
  
      if (!CheckStakeKernelHash(pindexPrev, nBits, *pblockindex, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug))
          return error("CheckProofOfStake() : INFO: check kernel failed on coinstake %s, hashProof=%s", tx.GetHash().ToString(), hashProofOfStake.ToString()); // may occur during initial download or if behind on block chain sync
  
      return true;
  }
  
  // Check whether the coinstake timestamp meets protocol
  bool CheckCoinStakeTimestamp(int nHeight, int64_t nTimeBlock, int64_t nTimeTx)
  {
      if (nHeight > 0)
          return (nTimeBlock == nTimeTx) && ((nTimeTx & STAKE_TIMESTAMP_MASK) == 0);
      else
          return (nTimeBlock == nTimeTx);
  }
  
  bool CheckKernel(CBlockIndex* pindexPrev, unsigned int nBits, int64_t nTime, const COutPoint& prevout, int64_t* pBlockTime)
  {
      arith_uint256 hashProofOfStake, targetProofOfStake;
  
      CTransaction txPrev;
      uint256 hashBlock = uint256();
      if (!GetTransaction(prevout.hash, txPrev, Params().GetConsensus(), hashBlock, true)){
          LogPrintf("CheckKernel : Could not find previous transaction %s\n",prevout.hash.ToString());
          return false;
      }
  
      if (mapBlockIndex.count(hashBlock) == 0){
          LogPrintf("CheckKernel : Could not find block of previous transaction %s\n",hashBlock.ToString());
          return false;
      }
  
      CBlockIndex* pblockindex = mapBlockIndex[hashBlock];
  
      if (pblockindex->GetBlockTime() + Params().GetConsensus().nStakeMinAge > nTime)
          return false;
  
      if (pBlockTime)
          *pBlockTime = pblockindex->GetBlockTime();
  
  
      if (!pwalletMain->mapWallet.count(prevout.hash))
          return("CheckProofOfStake(): Couldn't get Tx Index");
  
      return CheckStakeKernelHash(pindexPrev, nBits, *pblockindex, txPrev, prevout, nTime, hashProofOfStake, targetProofOfStake);
  }
  
  // staker's coin stake reward based on coin age spent (coin-days)
  int64_t GetProofOfStakeReward(int nHeight, int64_t nCoinAge, int64_t nFees, CBlockIndex* pindexPrev)
  {
    int64_t nSubsidy;
  
    if(IsStaticRewardEnabled(pindexPrev, Params().GetConsensus())){
        nSubsidy = Params().GetConsensus().nStaticReward;
    } else {
        int64_t nRewardCoinYear;
        nRewardCoinYear = MAX_MINT_PROOF_OF_STAKE;
  
        if(nHeight-1 < 7 * Params().GetConsensus().nDailyBlockCount)
            nRewardCoinYear = 1 * MAX_MINT_PROOF_OF_STAKE;
        else if(nHeight-1 < (365 * Params().GetConsensus().nDailyBlockCount))
            nRewardCoinYear = 0.5 * MAX_MINT_PROOF_OF_STAKE;
        else if(nHeight-1 < (730 * Params().GetConsensus().nDailyBlockCount))
            nRewardCoinYear = 0.5 * MAX_MINT_PROOF_OF_STAKE;
        else if(IsCommunityFundAccumulationEnabled(pindexPrev, Params().GetConsensus(), false))
            nRewardCoinYear = 0.4 * MAX_MINT_PROOF_OF_STAKE;
        else
            nRewardCoinYear = 0.5 * MAX_MINT_PROOF_OF_STAKE;
  
         nSubsidy = nCoinAge * nRewardCoinYear / 365;
    }
  
    return  nSubsidy + nFees;
  }
  
  unsigned int ComputeMaxBits(arith_uint256 bnTargetLimit, unsigned int nBase, int64_t nTime)
  {
      arith_uint256 bnResult;
      bnResult.SetCompact(nBase);
      bnResult *= 2;
      while (nTime > 0 && bnResult < bnTargetLimit)
      {
          // Maximum 200% adjustment per day...
          bnResult *= 2;
          nTime -= 24 * 60 * 60;
      }
      if (bnResult > bnTargetLimit)
          bnResult = bnTargetLimit;
      return bnResult.GetCompact();
  }
  