text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2012 The Bitcoin developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "alert.h"
  #include "checkpoints.h"
  #include "db.h"
  #include "txdb.h"
  #include "net.h"
  #include "init.h"
  #include "ui_interface.h"
  #include "kernel.h"
  #include <boost/algorithm/string/replace.hpp>
  #include <boost/filesystem.hpp>
  #include <boost/filesystem/fstream.hpp>
  
  
  using namespace std;
  using namespace boost;
  
  //
  // Global state
  //
  
  CCriticalSection cs_setpwalletRegistered;
  set<CWallet*> setpwalletRegistered;
  
  CCriticalSection cs_main;
  
  CTxMemPool mempool;
  unsigned int nTransactionsUpdated = 0;
  
  map<uint256, CBlockIndex*> mapBlockIndex;
  set<pair<COutPoint, unsigned int> > setStakeSeen;
  
  CBigNum bnProofOfWorkLimit(~uint256(0) >> 20);
  CBigNum bnProofOfStakeLimit(~uint256(0) >> 20);
  CBigNum bnProofOfWorkLimitTestNet(~uint256(0) >> 16);
  
  unsigned int nTargetSpacing = 60 ;
  unsigned int nTargetSpacing_2 = 150;
  
  unsigned int nStakeMinAge = 1 * 10 * 60; // 10 minutes
  unsigned int nStakeMinAge_2 = 24 * 60 * 60; // 24 hours
  unsigned int nStakeMaxAge = 30 * 24 * 60 * 60; // 30 days
  unsigned int nModifierInterval = 10 * 60; // time to elapse before new modifier is computed
  
  static const int64_t nTargetTimespan = 10 * 60;
  static const int64_t nTargetTimespan_2 = 24 * 60 * 60;
  
  int nCoinbaseMaturity = 40;
  CBlockIndex* pindexGenesisBlock = NULL;
  int nBestHeight = -1;
  
  uint256 nBestChainTrust = 0;
  uint256 nBestInvalidTrust = 0;
  
  uint256 hashBestChain = 0;
  CBlockIndex* pindexBest = NULL;
  int64_t nTimeBestReceived = 0;
  
  CMedianFilter<int> cPeerBlockCounts(5, 0); // Amount of blocks that other nodes claim to have
  
  map<uint256, CBlock*> mapOrphanBlocks;
  multimap<uint256, CBlock*> mapOrphanBlocksByPrev;
  set<pair<COutPoint, unsigned int> > setStakeSeenOrphan;
  
  map<uint256, CTransaction> mapOrphanTransactions;
  map<uint256, set<uint256> > mapOrphanTransactionsByPrev;
  
  // Constant stuff for coinbase transactions we create:
  CScript COINBASE_FLAGS;
  
  const string strMessageMagic = "bumbacoin2 Signed Message:\n";
  
  // Settings
  int64_t nTransactionFee = MIN_TX_FEE;
  int64_t nReserveBalance = 0;
  int64_t nMinimumInputValue = 0;
  int64_t nCombineThreshold = DEF_COMBINE_AMOUNT;
  int64_t nSplitThreshold = DEF_SPLIT_AMOUNT;
  
  extern enum Checkpoints::CPMode CheckpointsMode;
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // dispatching functions
  //
  
  // These functions dispatch to one or all registered wallets
  
  
  void RegisterWallet(CWallet* pwalletIn)
  {
      {
          LOCK(cs_setpwalletRegistered);
          setpwalletRegistered.insert(pwalletIn);
      }
  }
  
  void UnregisterWallet(CWallet* pwalletIn)
  {
      {
          LOCK(cs_setpwalletRegistered);
          setpwalletRegistered.erase(pwalletIn);
      }
  }
  
  // check whether the passed transaction is from us
  bool static IsFromMe(CTransaction& tx)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          if (pwallet->IsFromMe(tx))
              return true;
      return false;
  }
  
  // get the wallet transaction with the given hash (if it exists)
  bool static GetTransaction(const uint256& hashTx, CWalletTx& wtx)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          if (pwallet->GetTransaction(hashTx,wtx))
              return true;
      return false;
  }
  
  // erases transaction with the given hash from all wallets
  void static EraseFromWallets(uint256 hash)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->EraseFromWallet(hash);
  }
  
  // make sure all wallets know about the given transaction, in the given block
  void SyncWithWallets(const CTransaction& tx, const CBlock* pblock, bool fUpdate, bool fConnect)
  {
      if (!fConnect)
      {
          // ppcoin: wallets need to refund inputs when disconnecting coinstake
          if (tx.IsCoinStake())
          {
              BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
                  if (pwallet->IsFromMe(tx))
                      pwallet->DisableTransaction(tx);
          }
          return;
      }
  
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->AddToWalletIfInvolvingMe(tx, pblock, fUpdate);
  }
  
  // notify wallets about a new best chain
  void static SetBestChain(const CBlockLocator& loc)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->SetBestChain(loc);
  }
  
  // notify wallets about an updated transaction
  void static UpdatedTransaction(const uint256& hashTx)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->UpdatedTransaction(hashTx);
  }
  
  // dump all wallets
  void static PrintWallets(const CBlock& block)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->PrintWallet(block);
  }
  
  // notify wallets about an incoming inventory (for request counts)
  void static Inventory(const uint256& hash)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->Inventory(hash);
  }
  
  // ask wallets to resend their transactions
  void ResendWalletTransactions(bool fForce)
  {
      BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
          pwallet->ResendWalletTransactions(fForce);
  }
  
  
  
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // mapOrphanTransactions
  //
  
  bool AddOrphanTx(const CTransaction& tx)
  {
      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.
      // 10,000 orphans, each of which is at most 5,000 bytes big is
      // at most 500 megabytes of orphans:
  
      size_t nSize = tx.GetSerializeSize(SER_NETWORK, CTransaction::CURRENT_VERSION);
  
      if (nSize > 5000)
      {
          printf("ignoring large orphan tx (size: %"PRIszu", hash: %s)\n", nSize, hash.ToString().substr(0,10).c_str());
          return false;
      }
  
      mapOrphanTransactions[hash] = tx;
      BOOST_FOREACH(const CTxIn& txin, tx.vin)
          mapOrphanTransactionsByPrev[txin.prevout.hash].insert(hash);
  
      printf("stored orphan tx %s (mapsz %"PRIszu")\n", hash.ToString().substr(0,10).c_str(),
          mapOrphanTransactions.size());
      return true;
  }
  
  void static EraseOrphanTx(uint256 hash)
  {
      if (!mapOrphanTransactions.count(hash))
          return;
      const CTransaction& tx = mapOrphanTransactions[hash];
      BOOST_FOREACH(const CTxIn& txin, tx.vin)
      {
          mapOrphanTransactionsByPrev[txin.prevout.hash].erase(hash);
          if (mapOrphanTransactionsByPrev[txin.prevout.hash].empty())
              mapOrphanTransactionsByPrev.erase(txin.prevout.hash);
      }
      mapOrphanTransactions.erase(hash);
  }
  
  unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
  {
      unsigned int nEvicted = 0;
      while (mapOrphanTransactions.size() > nMaxOrphans)
      {
          // Evict a random orphan:
          uint256 randomhash = GetRandHash();
          map<uint256, CTransaction>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
          if (it == mapOrphanTransactions.end())
              it = mapOrphanTransactions.begin();
          EraseOrphanTx(it->first);
          ++nEvicted;
      }
      return nEvicted;
  }
  
  
  
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // CTransaction and CTxIndex
  //
  
  bool CTransaction::ReadFromDisk(CTxDB& txdb, COutPoint prevout, CTxIndex& txindexRet)
  {
      SetNull();
      if (!txdb.ReadTxIndex(prevout.hash, txindexRet))
          return false;
      if (!ReadFromDisk(txindexRet.pos))
          return false;
      if (prevout.n >= vout.size())
      {
          SetNull();
          return false;
      }
      return true;
  }
  
  bool CTransaction::ReadFromDisk(CTxDB& txdb, COutPoint prevout)
  {
      CTxIndex txindex;
      return ReadFromDisk(txdb, prevout, txindex);
  }
  
  bool CTransaction::ReadFromDisk(COutPoint prevout)
  {
      CTxDB txdb("r");
      CTxIndex txindex;
      return ReadFromDisk(txdb, prevout, txindex);
  }
  
  bool CTransaction::IsStandard() const
  {
      if (nVersion > CTransaction::CURRENT_VERSION)
          return false;
  
      BOOST_FOREACH(const CTxIn& txin, vin)
      {
          // Biggest 'standard' txin is a 3-signature 3-of-3 CHECKMULTISIG
          // pay-to-script-hash, which is 3 ~80-byte signatures, 3
          // ~65-byte public keys, plus a few script ops.
          if (txin.scriptSig.size() > 500)
              return false;
          if (!txin.scriptSig.IsPushOnly())
              return false;
          if (fEnforceCanonical && !txin.scriptSig.HasCanonicalPushes()) {
              return false;
          }
      }
      BOOST_FOREACH(const CTxOut& txout, vout) {
          if (!::IsStandard(txout.scriptPubKey))
              return false;
          if (txout.nValue == 0)
              return false;
          if (fEnforceCanonical && !txout.scriptPubKey.HasCanonicalPushes()) {
              return false;
          }
      }
      return true;
  }
  
  //
  // Check transaction inputs, and make sure any
  // pay-to-script-hash transactions are evaluating IsStandard scripts
  //
  // Why bother? To avoid denial-of-service attacks; an attacker
  // can submit a standard HASH... OP_EQUAL transaction,
  // which will get accepted into blocks. The redemption
  // script can be anything; an attacker could use a very
  // expensive-to-check-upon-redemption script like:
  //   DUP CHECKSIG DROP ... repeated 100 times... OP_1
  //
  bool CTransaction::AreInputsStandard(const MapPrevTx& mapInputs) const
  {
      if (IsCoinBase())
          return true; // Coinbases don't use vin normally
  
      for (unsigned int i = 0; i < vin.size(); i++)
      {
          const CTxOut& prev = GetOutputFor(vin[i], mapInputs);
  
          vector<vector<unsigned char> > vSolutions;
          txnouttype whichType;
          // get the scriptPubKey corresponding to this input:
          const CScript& prevScript = prev.scriptPubKey;
          if (!Solver(prevScript, whichType, vSolutions))
              return false;
          int nArgsExpected = ScriptSigArgsExpected(whichType, vSolutions);
          if (nArgsExpected < 0)
              return false;
  
          // Transactions with extra stuff in their scriptSigs are
          // non-standard. Note that this EvalScript() call will
          // be quick, because if there are any operations
          // beside "push data" in the scriptSig the
          // IsStandard() call returns false
          vector<vector<unsigned char> > stack;
          if (!EvalScript(stack, vin[i].scriptSig, *this, i, 0))
              return false;
  
          if (whichType == TX_SCRIPTHASH)
          {
              if (stack.empty())
                  return false;
              CScript subscript(stack.back().begin(), stack.back().end());
              vector<vector<unsigned char> > vSolutions2;
              txnouttype whichType2;
              if (!Solver(subscript, whichType2, vSolutions2))
                  return false;
              if (whichType2 == TX_SCRIPTHASH)
                  return false;
  
              int tmpExpected;
              tmpExpected = ScriptSigArgsExpected(whichType2, vSolutions2);
              if (tmpExpected < 0)
                  return false;
              nArgsExpected += tmpExpected;
          }
  
          if (stack.size() != (unsigned int)nArgsExpected)
              return false;
      }
  
      return true;
  }
  
  unsigned int
  CTransaction::GetLegacySigOpCount() const
  {
      unsigned int nSigOps = 0;
      BOOST_FOREACH(const CTxIn& txin, vin)
      {
          nSigOps += txin.scriptSig.GetSigOpCount(false);
      }
      BOOST_FOREACH(const CTxOut& txout, vout)
      {
          nSigOps += txout.scriptPubKey.GetSigOpCount(false);
      }
      return nSigOps;
  }
  
  
  int CMerkleTx::SetMerkleBranch(const CBlock* pblock)
  {
      if (fClient)
      {
          if (hashBlock == 0)
              return 0;
      }
      else
      {
          CBlock blockTmp;
          if (pblock == NULL)
          {
              // Load the block this tx is in
              CTxIndex txindex;
              if (!CTxDB("r").ReadTxIndex(GetHash(), txindex))
                  return 0;
              if (!blockTmp.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos))
                  return 0;
              pblock = &blockTmp;
          }
  
          // Update the tx's hashBlock
          hashBlock = pblock->GetHash();
  
          // Locate the transaction
          for (nIndex = 0; nIndex < (int)pblock->vtx.size(); nIndex++)
              if (pblock->vtx[nIndex] == *(CTransaction*)this)
                  break;
          if (nIndex == (int)pblock->vtx.size())
          {
              vMerkleBranch.clear();
              nIndex = -1;
              printf("ERROR: SetMerkleBranch() : couldn't find tx in block\n");
              return 0;
          }
  
          // Fill in merkle branch
          vMerkleBranch = pblock->GetMerkleBranch(nIndex);
      }
  
      // Is the tx in a block that's in the main chain
      map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
      if (mi == mapBlockIndex.end())
          return 0;
      CBlockIndex* pindex = (*mi).second;
      if (!pindex || !pindex->IsInMainChain())
          return 0;
  
      return pindexBest->nHeight - pindex->nHeight + 1;
  }
  
  
  
  
  
  
  
  bool CTransaction::CheckTransaction() const
  {
      // Basic checks that don't depend on any context
      if (vin.empty())
          return DoS(10, error("CTransaction::CheckTransaction() : vin empty"));
      if (vout.empty())
          return DoS(10, error("CTransaction::CheckTransaction() : vout empty"));
      // Size limits
      if (::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
          return DoS(100, error("CTransaction::CheckTransaction() : size limits failed"));
  
      // Check for negative or overflow output values
      int64_t nValueOut = 0;
      for (unsigned int i = 0; i < vout.size(); i++)
      {
          const CTxOut& txout = vout[i];
          if (txout.IsEmpty() && !IsCoinBase() && !IsCoinStake())
              return DoS(100, error("CTransaction::CheckTransaction() : txout empty for user transaction"));
          if (txout.nValue < 0)
              return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue negative"));
          if (txout.nValue > MAX_MONEY)
              return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue too high"));
          nValueOut += txout.nValue;
          if (!MoneyRange(nValueOut))
              return DoS(100, error("CTransaction::CheckTransaction() : txout total out of range"));
      }
  
      // Check for duplicate inputs
      set<COutPoint> vInOutPoints;
      BOOST_FOREACH(const CTxIn& txin, vin)
      {
          if (vInOutPoints.count(txin.prevout))
              return false;
          vInOutPoints.insert(txin.prevout);
      }
  
      if (IsCoinBase())
      {
          if (vin[0].scriptSig.size() < 2 || vin[0].scriptSig.size() > 100)
              return DoS(100, error("CTransaction::CheckTransaction() : coinbase script size is invalid"));
      }
      else
      {
          BOOST_FOREACH(const CTxIn& txin, vin)
              if (txin.prevout.IsNull())
                  return DoS(10, error("CTransaction::CheckTransaction() : prevout is null"));
      }
  
      return true;
  }
  
  int64_t CTransaction::GetMinFee(unsigned int nBlockSize, enum GetMinFee_mode mode, unsigned int nBytes) const
  {
      // Base fee is either MIN_TX_FEE or MIN_RELAY_TX_FEE
      int64_t nBaseFee = (mode == GMF_RELAY) ? MIN_RELAY_TX_FEE : MIN_TX_FEE;
  
      unsigned int nNewBlockSize = nBlockSize + nBytes;
      int64_t nMinFee = (1 + (int64_t)nBytes / 1000) * nBaseFee;
  
      // To limit dust spam, require MIN_TX_FEE/MIN_RELAY_TX_FEE if any output is less than 0.01
      if (nMinFee < nBaseFee)
      {
          BOOST_FOREACH(const CTxOut& txout, vout)
              if (txout.nValue < CENT)
                  nMinFee = nBaseFee;
      }
  
      // Raise the price as the block approaches full
      if (nBlockSize != 1 && nNewBlockSize >= MAX_BLOCK_SIZE_GEN/2)
      {
          if (nNewBlockSize >= MAX_BLOCK_SIZE_GEN)
              return MAX_MONEY;
          nMinFee *= MAX_BLOCK_SIZE_GEN / (MAX_BLOCK_SIZE_GEN - nNewBlockSize);
      }
  
      if (!MoneyRange(nMinFee))
          nMinFee = MAX_MONEY;
      return nMinFee;
  }
  
  
  bool CTxMemPool::accept(CTxDB& txdb, CTransaction &tx, bool fCheckInputs,
                          bool* pfMissingInputs)
  {
      if (pfMissingInputs)
          *pfMissingInputs = false;
  
      if (!tx.CheckTransaction())
          return error("CTxMemPool::accept() : CheckTransaction failed");
  
      // Coinbase is only valid in a block, not as a loose transaction
      if (tx.IsCoinBase())
          return tx.DoS(100, error("CTxMemPool::accept() : coinbase as individual tx"));
  
      // ppcoin: coinstake is also only valid in a block, not as a loose transaction
      if (tx.IsCoinStake())
          return tx.DoS(100, error("CTxMemPool::accept() : coinstake as individual tx"));
  
      // To help v0.1.5 clients who would see it as a negative number
      if ((int64_t)tx.nLockTime > std::numeric_limits<int>::max())
          return error("CTxMemPool::accept() : not accepting nLockTime beyond 2038 yet");
  
      // Rather not work on nonstandard transactions (unless -testnet)
      if (!fTestNet && !tx.IsStandard())
          return error("CTxMemPool::accept() : nonstandard transaction type");
  
      // Do we already have it?
      uint256 hash = tx.GetHash();
      {
          LOCK(cs);
          if (mapTx.count(hash))
              return false;
      }
      if (fCheckInputs)
          if (txdb.ContainsTx(hash))
              return false;
  
      // Check for conflicts with in-memory transactions
      CTransaction* ptxOld = NULL;
      for (unsigned int i = 0; i < tx.vin.size(); i++)
      {
          COutPoint outpoint = tx.vin[i].prevout;
          if (mapNextTx.count(outpoint))
          {
              // Disable replacement feature for now
              return false;
  
              // Allow replacing with a newer version of the same transaction
              if (i != 0)
                  return false;
              ptxOld = mapNextTx[outpoint].ptx;
              if (ptxOld->IsFinal())
                  return false;
              if (!tx.IsNewerThan(*ptxOld))
                  return false;
              for (unsigned int i = 0; i < tx.vin.size(); i++)
              {
                  COutPoint outpoint = tx.vin[i].prevout;
                  if (!mapNextTx.count(outpoint) || mapNextTx[outpoint].ptx != ptxOld)
                      return false;
              }
              break;
          }
      }
  
      if (fCheckInputs)
      {
          MapPrevTx mapInputs;
          map<uint256, CTxIndex> mapUnused;
          bool fInvalid = false;
          if (!tx.FetchInputs(txdb, mapUnused, false, false, mapInputs, fInvalid))
          {
              if (fInvalid)
                  return error("CTxMemPool::accept() : FetchInputs found invalid tx %s", hash.ToString().substr(0,10).c_str());
              if (pfMissingInputs)
                  *pfMissingInputs = true;
              return false;
          }
  
          // Check for non-standard pay-to-script-hash in inputs
          if (!tx.AreInputsStandard(mapInputs) && !fTestNet)
              return error("CTxMemPool::accept() : nonstandard transaction input");
  
          // Note: if you modify this code to accept non-standard transactions, then
          // you should add code here to check that the transaction does a
          // reasonable number of ECDSA signature verifications.
  
          int64_t nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
          unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
  
          // Don't accept it if it can't get into a block
          int64_t txMinFee = tx.GetMinFee(1000, GMF_RELAY, nSize);
          if (nFees < txMinFee)
              return error("CTxMemPool::accept() : not enough fees %s, %"PRId64" < %"PRId64,
                           hash.ToString().c_str(),
                           nFees, txMinFee);
  
          // Continuously rate-limit free transactions
          // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
          // be annoying or make others' transactions take longer to confirm.
          if (nFees < MIN_RELAY_TX_FEE)
          {
              static CCriticalSection cs;
              static double dFreeCount;
              static int64_t nLastTime;
              int64_t nNow = GetTime();
  
              {
                  LOCK(cs);
                  // 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 > GetArg("-limitfreerelay", 15)*10*1000 && !IsFromMe(tx))
                      return error("CTxMemPool::accept() : free transaction rejected by rate limiter");
                  if (fDebug)
                      printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
                  dFreeCount += nSize;
              }
          }
  
          // Check against previous transactions
          // This is done last to help prevent CPU exhaustion denial-of-service attacks.
          if (!tx.ConnectInputs(txdb, mapInputs, mapUnused, CDiskTxPos(1,1,1), pindexBest, false, false))
          {
              return error("CTxMemPool::accept() : ConnectInputs failed %s", hash.ToString().substr(0,10).c_str());
          }
      }
  
      // Store transaction in memory
      {
          LOCK(cs);
          if (ptxOld)
          {
              printf("CTxMemPool::accept() : replacing tx %s with new version\n", ptxOld->GetHash().ToString().c_str());
              remove(*ptxOld);
          }
          addUnchecked(hash, tx);
      }
  
      ///// are we sure this is ok when loading transactions or restoring block txes
      // If updated, erase old tx from wallet
      if (ptxOld)
          EraseFromWallets(ptxOld->GetHash());
  
      printf("CTxMemPool::accept() : accepted %s (poolsz %"PRIszu")\n",
             hash.ToString().substr(0,10).c_str(),
             mapTx.size());
      return true;
  }
  
  bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMissingInputs)
  {
      return mempool.accept(txdb, *this, fCheckInputs, pfMissingInputs);
  }
  
  bool CTxMemPool::addUnchecked(const uint256& hash, CTransaction &tx)
  {
      // Add to memory pool without checking anything.  Don't call this directly,
      // call CTxMemPool::accept to properly check the transaction first.
      {
          mapTx[hash] = tx;
          for (unsigned int i = 0; i < tx.vin.size(); i++)
              mapNextTx[tx.vin[i].prevout] = CInPoint(&mapTx[hash], i);
          nTransactionsUpdated++;
      }
      return true;
  }
  
  
  bool CTxMemPool::remove(const CTransaction &tx, bool fRecursive)
  {
      // Remove transaction from memory pool
      {
          LOCK(cs);
          uint256 hash = tx.GetHash();
          if (mapTx.count(hash))
          {
              if (fRecursive) {
                  for (unsigned int i = 0; i < tx.vout.size(); i++) {
                      std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(COutPoint(hash, i));
                      if (it != mapNextTx.end())
                          remove(*it->second.ptx, true);
                  }
              }
              BOOST_FOREACH(const CTxIn& txin, tx.vin)
                  mapNextTx.erase(txin.prevout);
              mapTx.erase(hash);
              nTransactionsUpdated++;
          }
      }
      return true;
  }
  
  bool CTxMemPool::removeConflicts(const CTransaction &tx)
  {
      // Remove transactions which depend on inputs of tx, recursively
      LOCK(cs);
      BOOST_FOREACH(const CTxIn &txin, tx.vin) {
          std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(txin.prevout);
          if (it != mapNextTx.end()) {
              const CTransaction &txConflict = *it->second.ptx;
              if (txConflict != tx)
                  remove(txConflict, true);
          }
      }
      return true;
  }
  
  void CTxMemPool::clear()
  {
      LOCK(cs);
      mapTx.clear();
      mapNextTx.clear();
      ++nTransactionsUpdated;
  }
  
  void CTxMemPool::queryHashes(std::vector<uint256>& vtxid)
  {
      vtxid.clear();
  
      LOCK(cs);
      vtxid.reserve(mapTx.size());
      for (map<uint256, CTransaction>::iterator mi = mapTx.begin(); mi != mapTx.end(); ++mi)
          vtxid.push_back((*mi).first);
  }
  
  
  
  
  int CMerkleTx::GetDepthInMainChainINTERNAL(CBlockIndex* &pindexRet) const
  {
      if (hashBlock == 0 || nIndex == -1)
          return 0;
  
      // Find the block it claims to be in
      map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
      if (mi == mapBlockIndex.end())
          return 0;
      CBlockIndex* pindex = (*mi).second;
      if (!pindex || !pindex->IsInMainChain())
          return 0;
  
      // Make sure the merkle branch connects to this block
      if (!fMerkleVerified)
      {
          if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot)
              return 0;
          fMerkleVerified = true;
      }
  
      pindexRet = pindex;
      return pindexBest->nHeight - pindex->nHeight + 1;
  }
  
  int CMerkleTx::GetDepthInMainChain(CBlockIndex* &pindexRet) const
  {
      int nResult = GetDepthInMainChainINTERNAL(pindexRet);
      if (nResult == 0 && !mempool.exists(GetHash()))
          return -1; // Not in chain, not in mempool
  
      return nResult;
  }
  
  int CMerkleTx::GetBlocksToMaturity() const
  {
      if (!(IsCoinBase() || IsCoinStake()))
          return 0;
      return max(0, (nCoinbaseMaturity+20) - GetDepthInMainChain());
  }
  
  
  bool CMerkleTx::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs)
  {
      if (fClient)
      {
          if (!IsInMainChain() && !ClientConnectInputs())
              return false;
          return CTransaction::AcceptToMemoryPool(txdb, fCheckInputs);
      }
      else
      {
          return CTransaction::AcceptToMemoryPool(txdb, fCheckInputs);
      }
  }
  
  bool CMerkleTx::AcceptToMemoryPool()
  {
      CTxDB txdb("r");
      return AcceptToMemoryPool(txdb);
  }
  
  
  
  bool CWalletTx::AcceptWalletTransaction(CTxDB& txdb, bool fCheckInputs)
  {
  
      {
          LOCK(mempool.cs);
          // Add previous supporting transactions first
          BOOST_FOREACH(CMerkleTx& tx, vtxPrev)
          {
              if (!(tx.IsCoinBase() || tx.IsCoinStake()))
              {
                  uint256 hash = tx.GetHash();
                  if (!mempool.exists(hash) && !txdb.ContainsTx(hash))
                      tx.AcceptToMemoryPool(txdb, fCheckInputs);
              }
          }
          return AcceptToMemoryPool(txdb, fCheckInputs);
      }
      return false;
  }
  
  bool CWalletTx::AcceptWalletTransaction()
  {
      CTxDB txdb("r");
      return AcceptWalletTransaction(txdb);
  }
  
  int CTxIndex::GetDepthInMainChain() const
  {
      // Read block header
      CBlock block;
      if (!block.ReadFromDisk(pos.nFile, pos.nBlockPos, false))
          return 0;
      // Find the block in the index
      map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(block.GetHash());
      if (mi == mapBlockIndex.end())
          return 0;
      CBlockIndex* pindex = (*mi).second;
      if (!pindex || !pindex->IsInMainChain())
          return 0;
      return 1 + nBestHeight - pindex->nHeight;
  }
  
  // Return transaction in tx, and if it was found inside a block, its hash is placed in hashBlock
  bool GetTransaction(const uint256 &hash, CTransaction &tx, uint256 &hashBlock)
  {
      {
          LOCK(cs_main);
          {
              LOCK(mempool.cs);
              if (mempool.exists(hash))
              {
                  tx = mempool.lookup(hash);
                  return true;
              }
          }
          CTxDB txdb("r");
          CTxIndex txindex;
          if (tx.ReadFromDisk(txdb, COutPoint(hash, 0), txindex))
          {
              CBlock block;
              if (block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
                  hashBlock = block.GetHash();
              return true;
          }
      }
      return false;
  }
  
  
  
  
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // CBlock and CBlockIndex
  //
  
  static CBlockIndex* pblockindexFBBHLast;
  CBlockIndex* FindBlockByHeight(int nHeight)
  {
      CBlockIndex *pblockindex;
      if (nHeight < nBestHeight / 2)
          pblockindex = pindexGenesisBlock;
      else
          pblockindex = pindexBest;
      if (pblockindexFBBHLast && abs(nHeight - pblockindex->nHeight) > abs(nHeight - pblockindexFBBHLast->nHeight))
          pblockindex = pblockindexFBBHLast;
      while (pblockindex->nHeight > nHeight)
          pblockindex = pblockindex->pprev;
      while (pblockindex->nHeight < nHeight)
          pblockindex = pblockindex->pnext;
      pblockindexFBBHLast = pblockindex;
      return pblockindex;
  }
  
  bool CBlock::ReadFromDisk(const CBlockIndex* pindex, bool fReadTransactions)
  {
      if (!fReadTransactions)
      {
          *this = pindex->GetBlockHeader();
          return true;
      }
      if (!ReadFromDisk(pindex->nFile, pindex->nBlockPos, fReadTransactions))
          return false;
      if (GetHash() != pindex->GetBlockHash())
          return error("CBlock::ReadFromDisk() : GetHash() doesn't match index");
      return true;
  }
  
  uint256 static GetOrphanRoot(const CBlock* pblock)
  {
      // Work back to the first block in the orphan chain
      while (mapOrphanBlocks.count(pblock->hashPrevBlock))
          pblock = mapOrphanBlocks[pblock->hashPrevBlock];
      return pblock->GetHash();
  }
  
  // ppcoin: find block wanted by given orphan block
  uint256 WantedByOrphan(const CBlock* pblockOrphan)
  {
      // Work back to the first block in the orphan chain
      while (mapOrphanBlocks.count(pblockOrphan->hashPrevBlock))
          pblockOrphan = mapOrphanBlocks[pblockOrphan->hashPrevBlock];
      return pblockOrphan->hashPrevBlock;
  }
  
  int64_t GetProofOfWorkReward(int64_t nFees)
  {
      int64_t nSubsidy = 0 * COIN;
      
      if (pindexBest->nHeight == 1)
      {
        nSubsidy = 20000000 * COIN;
        return nSubsidy + nFees;
      }
      
      else if (pindexBest->nHeight <= 2)
      {
        nSubsidy = 0 * COIN;
        return nSubsidy + nFees;
      }
  
      if (fDebug && GetBoolArg("-printcreation"))
          printf("GetProofOfWorkReward() : create=%s nSubsidy=%"PRId64"\n", FormatMoney(nSubsidy).c_str(), nSubsidy);
  	
      return nSubsidy + nFees;
  }
  
  // miner's coin stake reward based on coin age spent (coin-days)
  int64_t GetProofOfStakeReward(int64_t nCoinAge, int64_t nFees)
  {
      int64_t nRewardCoinYear;
      nRewardCoinYear = MAX_MINT_PROOF_OF_STAKE;
  
      int64_t nSubsidy = 0 * COIN;
  
      if (pindexBest->nHeight <= LAST_POW_BLOCK)
        {
        int64_t nSubsidy = nCoinAge * nRewardCoinYear / 365 / COIN;
        return nSubsidy + nFees;
        }
  
      else if (pindexBest->nHeight > LAST_POW_BLOCK && pindexBest->nHeight < HARD_FORK_DIFF_FIX)
        {
        int64_t nSubsidy = 2 * COIN;
        return nSubsidy + nFees;
        }
  
      else // increase reward to match increased block time
        {
        int64_t nSubsidy = 5 * COIN;
        return nSubsidy + nFees;
        }
  
      if (fDebug && GetBoolArg("-printcreation"))
          printf("GetProofOfStakeReward(): create=%s nCoinAge=%"PRId64"\n", FormatMoney(nSubsidy).c_str(), nCoinAge);
  
      return nSubsidy + nFees;
  }
  
  //
  // maximum nBits value could possible be required nTime after
  //
  unsigned int ComputeMaxBits(CBigNum bnTargetLimit, unsigned int nBase, int64_t nTime)
  {
      CBigNum 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();
  }
  
  //
  // minimum amount of work that could possibly be required nTime after
  // minimum proof-of-work required was nBase
  //
  unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime)
  {
      return ComputeMaxBits(bnProofOfWorkLimit, nBase, nTime);
  }
  
  //
  // minimum amount of stake that could possibly be required nTime after
  // minimum proof-of-stake required was nBase
  //
  unsigned int ComputeMinStake(unsigned int nBase, int64_t nTime, unsigned int nBlockTime)
  {
      return ComputeMaxBits(bnProofOfStakeLimit, nBase, nTime);
  }
  
  
  // 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;
  }
  
  static unsigned int GetNextTargetRequired_(const CBlockIndex* pindexLast, bool fProofOfStake)
  {
      CBigNum bnTargetLimit = fProofOfStake ? bnProofOfStakeLimit : bnProofOfWorkLimit;
  
      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(pindexBest->nHeight < HARD_FORK_DIFF_FIX )
  	{	if (nActualSpacing < 0)
          	nActualSpacing = nTargetSpacing;	}
  	unsigned int nSpacing = pindexBest->nHeight < HARD_FORK_DIFF_FIX ? nTargetSpacing : nTargetSpacing_2;
  
      // ppcoin: target change every block
      // ppcoin: retarget with exponential moving toward target spacing
      CBigNum bnNew;
      bnNew.SetCompact(pindexPrev->nBits);
  	int64_t nInterval = (pindexBest->nHeight < HARD_FORK_DIFF_FIX ? nTargetTimespan : nTargetTimespan_2) / nSpacing;
      bnNew *= ((nInterval - 1) * nSpacing + nActualSpacing + nActualSpacing);
      bnNew /= ((nInterval + 1) * nSpacing);
  
      if (bnNew <= 0 || bnNew > bnTargetLimit)
          bnNew = bnTargetLimit;
  
      return bnNew.GetCompact();
  }
  
  unsigned int GetNextTargetRequired(const CBlockIndex* pindexLast, bool fProofOfStake)
  {
      return GetNextTargetRequired_(pindexLast, fProofOfStake);
  }
  
  bool CheckProofOfWork(uint256 hash, unsigned int nBits)
  {
      CBigNum bnTarget;
      bnTarget.SetCompact(nBits);
  
      // Check range
      if (bnTarget <= 0 || bnTarget > bnProofOfWorkLimit)
          return error("CheckProofOfWork() : nBits below minimum work");
  
      // Check proof of work matches claimed amount
      if (hash > bnTarget.getuint256())
          return error("CheckProofOfWork() : hash doesn't match nBits");
  
      return true;
  }
  
  // Return maximum amount of blocks that other nodes claim to have
  int GetNumBlocksOfPeers()
  {
      return std::max(cPeerBlockCounts.median(), Checkpoints::GetTotalBlocksEstimate());
  }
  
  bool IsInitialBlockDownload()
  {
      if (pindexBest == NULL || nBestHeight < Checkpoints::GetTotalBlocksEstimate())
          return true;
      static int64_t nLastUpdate;
      static CBlockIndex* pindexLastBest;
      if (pindexBest != pindexLastBest)
      {
          pindexLastBest = pindexBest;
          nLastUpdate = GetTime();
      }
      return (GetTime() - nLastUpdate < 10 &&
              pindexBest->GetBlockTime() < GetTime() - 24 * 60 * 60);
  }
  
  void static InvalidChainFound(CBlockIndex* pindexNew)
  {
      if (pindexNew->nChainTrust > nBestInvalidTrust)
      {
          nBestInvalidTrust = pindexNew->nChainTrust;
          CTxDB().WriteBestInvalidTrust(CBigNum(nBestInvalidTrust));
          uiInterface.NotifyBlocksChanged();
      }
  
      uint256 nBestInvalidBlockTrust = pindexNew->nChainTrust - pindexNew->pprev->nChainTrust;
      uint256 nBestBlockTrust = pindexBest->nHeight != 0 ? (pindexBest->nChainTrust - pindexBest->pprev->nChainTrust) : pindexBest->nChainTrust;
  
      printf("InvalidChainFound: invalid block=%s  height=%d  trust=%s  blocktrust=%"PRId64"  date=%s\n",
        pindexNew->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->nHeight,
        CBigNum(pindexNew->nChainTrust).ToString().c_str(), nBestInvalidBlockTrust.Get64(),
        DateTimeStrFormat("%x %H:%M:%S", pindexNew->GetBlockTime()).c_str());
      printf("InvalidChainFound:  current best=%s  height=%d  trust=%s  blocktrust=%"PRId64"  date=%s\n",
        hashBestChain.ToString().substr(0,20).c_str(), nBestHeight,
        CBigNum(pindexBest->nChainTrust).ToString().c_str(),
        nBestBlockTrust.Get64(),
        DateTimeStrFormat("%x %H:%M:%S", pindexBest->GetBlockTime()).c_str());
  }
  
  
  void CBlock::UpdateTime(const CBlockIndex* pindexPrev)
  {
      nTime = max(GetBlockTime(), GetAdjustedTime());
  }
  
  
  
  
  bool CTransaction::DisconnectInputs(CTxDB& txdb)
  {
      // Relinquish previous transactions' spent pointers
      if (!IsCoinBase())
      {
          BOOST_FOREACH(const CTxIn& txin, vin)
          {
              COutPoint prevout = txin.prevout;
  
              // Get prev txindex from disk
              CTxIndex txindex;
              if (!txdb.ReadTxIndex(prevout.hash, txindex))
                  return error("DisconnectInputs() : ReadTxIndex failed");
  
              if (prevout.n >= txindex.vSpent.size())
                  return error("DisconnectInputs() : prevout.n out of range");
  
              // Mark outpoint as not spent
              txindex.vSpent[prevout.n].SetNull();
  
              // Write back
              if (!txdb.UpdateTxIndex(prevout.hash, txindex))
                  return error("DisconnectInputs() : UpdateTxIndex failed");
          }
      }
  
      // Remove transaction from index
      // This can fail if a duplicate of this transaction was in a chain that got
      // reorganized away. This is only possible if this transaction was completely
      // spent, so erasing it would be a no-op anyway.
      txdb.EraseTxIndex(*this);
  
      return true;
  }
  
  
  bool CTransaction::FetchInputs(CTxDB& txdb, const map<uint256, CTxIndex>& mapTestPool,
                                 bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid)
  {
      // FetchInputs can return false either because we just haven't seen some inputs
      // (in which case the transaction should be stored as an orphan)
      // or because the transaction is malformed (in which case the transaction should
      // be dropped).  If tx is definitely invalid, fInvalid will be set to true.
      fInvalid = false;
  
      if (IsCoinBase())
          return true; // Coinbase transactions have no inputs to fetch.
  
      for (unsigned int i = 0; i < vin.size(); i++)
      {
          COutPoint prevout = vin[i].prevout;
          if (inputsRet.count(prevout.hash))
              continue; // Got it already
  
          // Read txindex
          CTxIndex& txindex = inputsRet[prevout.hash].first;
          bool fFound = true;
          if ((fBlock || fMiner) && mapTestPool.count(prevout.hash))
          {
              // Get txindex from current proposed changes
              txindex = mapTestPool.find(prevout.hash)->second;
          }
          else
          {
              // Read txindex from txdb
              fFound = txdb.ReadTxIndex(prevout.hash, txindex);
          }
          if (!fFound && (fBlock || fMiner))
              return fMiner ? false : error("FetchInputs() : %s prev tx %s index entry not found", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
  
          // Read txPrev
          CTransaction& txPrev = inputsRet[prevout.hash].second;
          if (!fFound || txindex.pos == CDiskTxPos(1,1,1))
          {
              // Get prev tx from single transactions in memory
              {
                  LOCK(mempool.cs);
                  if (!mempool.exists(prevout.hash))
                      return error("FetchInputs() : %s mempool Tx prev not found %s", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
                  txPrev = mempool.lookup(prevout.hash);
              }
              if (!fFound)
                  txindex.vSpent.resize(txPrev.vout.size());
          }
          else
          {
              // Get prev tx from disk
              if (!txPrev.ReadFromDisk(txindex.pos))
                  return error("FetchInputs() : %s ReadFromDisk prev tx %s failed", GetHash().ToString().substr(0,10).c_str(),  prevout.hash.ToString().substr(0,10).c_str());
          }
      }
  
      // Make sure all prevout.n indexes are valid:
      for (unsigned int i = 0; i < vin.size(); i++)
      {
          const COutPoint prevout = vin[i].prevout;
          assert(inputsRet.count(prevout.hash) != 0);
          const CTxIndex& txindex = inputsRet[prevout.hash].first;
          const CTransaction& txPrev = inputsRet[prevout.hash].second;
          if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
          {
              // Revisit this if/when transaction replacement is implemented and allows
              // adding inputs:
              fInvalid = true;
              return DoS(100, error("FetchInputs() : %s prevout.n out of range %d %"PRIszu" %"PRIszu" prev tx %s\n%s", GetHash().ToString().substr(0,10).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size(), prevout.hash.ToString().substr(0,10).c_str(), txPrev.ToString().c_str()));
          }
      }
  
      return true;
  }
  
  const CTxOut& CTransaction::GetOutputFor(const CTxIn& input, const MapPrevTx& inputs) const
  {
      MapPrevTx::const_iterator mi = inputs.find(input.prevout.hash);
      if (mi == inputs.end())
          throw std::runtime_error("CTransaction::GetOutputFor() : prevout.hash not found");
  
      const CTransaction& txPrev = (mi->second).second;
      if (input.prevout.n >= txPrev.vout.size())
          throw std::runtime_error("CTransaction::GetOutputFor() : prevout.n out of range");
  
      return txPrev.vout[input.prevout.n];
  }
  
  int64_t CTransaction::GetValueIn(const MapPrevTx& inputs) const
  {
      if (IsCoinBase())
          return 0;
  
      int64_t nResult = 0;
      for (unsigned int i = 0; i < vin.size(); i++)
      {
          nResult += GetOutputFor(vin[i], inputs).nValue;
      }
      return nResult;
  
  }
  
  unsigned int CTransaction::GetP2SHSigOpCount(const MapPrevTx& inputs) const
  {
      if (IsCoinBase())
          return 0;
  
      unsigned int nSigOps = 0;
      for (unsigned int i = 0; i < vin.size(); i++)
      {
          const CTxOut& prevout = GetOutputFor(vin[i], inputs);
          if (prevout.scriptPubKey.IsPayToScriptHash())
              nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
      }
      return nSigOps;
  }
  
  bool CTransaction::ConnectInputs(CTxDB& txdb, MapPrevTx inputs, map<uint256, CTxIndex>& mapTestPool, const CDiskTxPos& posThisTx,
      const CBlockIndex* pindexBlock, bool fBlock, bool fMiner)
  {
      // Take over previous transactions' spent pointers
      // fBlock is true when this is called from AcceptBlock when a new best-block is added to the blockchain
      // fMiner is true when called from the internal bitcoin miner
      // ... both are false when called from CTransaction::AcceptToMemoryPool
      if (!IsCoinBase())
      {
          int64_t nValueIn = 0;
          int64_t nFees = 0;
          for (unsigned int i = 0; i < vin.size(); i++)
          {
              COutPoint prevout = vin[i].prevout;
              assert(inputs.count(prevout.hash) > 0);
              CTxIndex& txindex = inputs[prevout.hash].first;
              CTransaction& txPrev = inputs[prevout.hash].second;
  
              if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
                  return DoS(100, error("ConnectInputs() : %s prevout.n out of range %d %"PRIszu" %"PRIszu" prev tx %s\n%s", GetHash().ToString().substr(0,10).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size(), prevout.hash.ToString().substr(0,10).c_str(), txPrev.ToString().c_str()));
  
              // If prev is coinbase or coinstake, check that it's matured
              if (txPrev.IsCoinBase() || txPrev.IsCoinStake())
                  for (const CBlockIndex* pindex = pindexBlock; pindex && pindexBlock->nHeight - pindex->nHeight < nCoinbaseMaturity; pindex = pindex->pprev)
                      if (pindex->nBlockPos == txindex.pos.nBlockPos && pindex->nFile == txindex.pos.nFile)
                          return error("ConnectInputs() : tried to spend %s at depth %d", txPrev.IsCoinBase() ? "coinbase" : "coinstake", pindexBlock->nHeight - pindex->nHeight);
  
              // ppcoin: check transaction timestamp
              if (txPrev.nTime > nTime)
                  return DoS(100, error("ConnectInputs() : transaction timestamp earlier than input transaction"));
  
              // Check for negative or overflow input values
              nValueIn += txPrev.vout[prevout.n].nValue;
              if (!MoneyRange(txPrev.vout[prevout.n].nValue) || !MoneyRange(nValueIn))
                  return DoS(100, error("ConnectInputs() : txin values out of range"));
  
          }
          // 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.
          for (unsigned int i = 0; i < vin.size(); i++)
          {
              COutPoint prevout = vin[i].prevout;
              assert(inputs.count(prevout.hash) > 0);
              CTxIndex& txindex = inputs[prevout.hash].first;
              CTransaction& txPrev = inputs[prevout.hash].second;
  
              // Check for conflicts (double-spend)
              // 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 (!txindex.vSpent[prevout.n].IsNull())
                  return fMiner ? false : error("ConnectInputs() : %s prev tx already used at %s", GetHash().ToString().substr(0,10).c_str(), txindex.vSpent[prevout.n].ToString().c_str());
  
              // Skip ECDSA signature verification when connecting blocks (fBlock=true)
              // before the last blockchain checkpoint. This is safe because block merkle hashes are
              // still computed and checked, and any change will be caught at the next checkpoint.
              if (!(fBlock && (nBestHeight < Checkpoints::GetTotalBlocksEstimate())))
              {
                  // Verify signature
                  if (!VerifySignature(txPrev, *this, i, 0))
                  {
                      return DoS(100,error("ConnectInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
                  }
              }
  
              // Mark outpoints as spent
              txindex.vSpent[prevout.n] = posThisTx;
  
              // Write back
              if (fBlock || fMiner)
              {
                  mapTestPool[prevout.hash] = txindex;
              }
          }
  
          if (!IsCoinStake())
          {
              if (nValueIn < GetValueOut())
                  return DoS(100, error("ConnectInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));
  
              // Tally transaction fees
              int64_t nTxFee = nValueIn - GetValueOut();
              if (nTxFee < 0)
                  return DoS(100, error("ConnectInputs() : %s nTxFee < 0", GetHash().ToString().substr(0,10).c_str()));
  
              // enforce transaction fees for every block
              if (nTxFee < GetMinFee())
                  return fBlock? DoS(100, error("ConnectInputs() : %s not paying required fee=%s, paid=%s", GetHash().ToString().substr(0,10).c_str(), FormatMoney(GetMinFee()).c_str(), FormatMoney(nTxFee).c_str())) : false;
  
              nFees += nTxFee;
              if (!MoneyRange(nFees))
                  return DoS(100, error("ConnectInputs() : nFees out of range"));
          }
      }
  
      return true;
  }
  
  
  bool CTransaction::ClientConnectInputs()
  {
      if (IsCoinBase())
          return false;
  
      // Take over previous transactions' spent pointers
      {
          LOCK(mempool.cs);
          int64_t nValueIn = 0;
          for (unsigned int i = 0; i < vin.size(); i++)
          {
              // Get prev tx from single transactions in memory
              COutPoint prevout = vin[i].prevout;
              if (!mempool.exists(prevout.hash))
                  return false;
              CTransaction& txPrev = mempool.lookup(prevout.hash);
  
              if (prevout.n >= txPrev.vout.size())
                  return false;
  
              // Verify signature
              if (!VerifySignature(txPrev, *this, i, 0))
                  return error("ConnectInputs() : VerifySignature failed");
  
              nValueIn += txPrev.vout[prevout.n].nValue;
  
              if (!MoneyRange(txPrev.vout[prevout.n].nValue) || !MoneyRange(nValueIn))
                  return error("ClientConnectInputs() : txin values out of range");
          }
          if (GetValueOut() > nValueIn)
              return false;
      }
  
      return true;
  }
  
  
  
  
  bool CBlock::DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex)
  {
      // Disconnect in reverse order
      for (int i = vtx.size()-1; i >= 0; i--)
          if (!vtx[i].DisconnectInputs(txdb))
              return false;
  
      // Update block index on disk without changing it in memory.
      // The memory index structure will be changed after the db commits.
      if (pindex->pprev)
      {
          CDiskBlockIndex blockindexPrev(pindex->pprev);
          blockindexPrev.hashNext = 0;
          if (!txdb.WriteBlockIndex(blockindexPrev))
              return error("DisconnectBlock() : WriteBlockIndex failed");
      }
  
      // ppcoin: clean up wallet after disconnecting coinstake
      BOOST_FOREACH(CTransaction& tx, vtx)
          SyncWithWallets(tx, this, false, false);
  
      return true;
  }
  
  bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
  {
      // Check it again in case a previous version let a bad block in, but skip BlockSig checking
      if (!CheckBlock(!fJustCheck, !fJustCheck, false))
          return false;
  
      //// issue here: it doesn't know the version
      unsigned int nTxPos;
      if (fJustCheck)
          // FetchInputs treats CDiskTxPos(1,1,1) as a special "refer to memorypool" indicator
          // Since we're just checking the block and not actually connecting it, it might not (and probably shouldn't) be on the disk to get the transaction from
          nTxPos = 1;
      else
          nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK, CLIENT_VERSION) - (2 * GetSizeOfCompactSize(0)) + GetSizeOfCompactSize(vtx.size());
  
      map<uint256, CTxIndex> mapQueuedChanges;
      int64_t nFees = 0;
      int64_t nValueIn = 0;
      int64_t nValueOut = 0;
      int64_t nStakeReward = 0;
      unsigned int nSigOps = 0;
      BOOST_FOREACH(CTransaction& tx, vtx)
      {
          uint256 hashTx = tx.GetHash();
  
          // 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 all blocks whose timestamp was 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 in their
          // initial block download.
          CTxIndex txindexOld;
          if (txdb.ReadTxIndex(hashTx, txindexOld)) {
              BOOST_FOREACH(CDiskTxPos &pos, txindexOld.vSpent)
                  if (pos.IsNull())
                      return false;
          }
  
          nSigOps += tx.GetLegacySigOpCount();
          if (nSigOps > MAX_BLOCK_SIGOPS)
              return DoS(100, error("ConnectBlock() : too many sigops"));
  
          CDiskTxPos posThisTx(pindex->nFile, pindex->nBlockPos, nTxPos);
          if (!fJustCheck)
              nTxPos += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
  
          MapPrevTx mapInputs;
          if (tx.IsCoinBase())
              nValueOut += tx.GetValueOut();
          else
          {
              bool fInvalid;
              if (!tx.FetchInputs(txdb, mapQueuedChanges, true, false, mapInputs, fInvalid))
                  return false;
  
              // Add in sigops done by pay-to-script-hash inputs;
              // this is to prevent a "rogue miner" from creating
              // an incredibly-expensive-to-validate block.
              nSigOps += tx.GetP2SHSigOpCount(mapInputs);
              if (nSigOps > MAX_BLOCK_SIGOPS)
                  return DoS(100, error("ConnectBlock() : too many sigops"));
  
              int64_t nTxValueIn = tx.GetValueIn(mapInputs);
              int64_t nTxValueOut = tx.GetValueOut();
              nValueIn += nTxValueIn;
              nValueOut += nTxValueOut;
              if (!tx.IsCoinStake())
                  nFees += nTxValueIn - nTxValueOut;
              if (tx.IsCoinStake())
                  nStakeReward = nTxValueOut - nTxValueIn;
  
              if (!tx.ConnectInputs(txdb, mapInputs, mapQueuedChanges, posThisTx, pindex, true, false))
                  return false;
          }
  
          mapQueuedChanges[hashTx] = CTxIndex(posThisTx, tx.vout.size());
      }
  
      if (IsProofOfWork())
      {
          int64_t nReward = GetProofOfWorkReward(nFees);
          // Check coinbase reward
          if (vtx[0].GetValueOut() > nReward)
              return DoS(50, error("ConnectBlock() : coinbase reward exceeded (actual=%"PRId64" vs calculated=%"PRId64")",
                     vtx[0].GetValueOut(),
                     nReward));
      }
      if (IsProofOfStake())
      {
          // ppcoin: coin stake tx earns reward instead of paying fee
          uint64_t nCoinAge;
          if (!vtx[1].GetCoinAge(txdb, nCoinAge))
              return error("ConnectBlock() : %s unable to get coin age for coinstake", vtx[1].GetHash().ToString().substr(0,10).c_str());
  
          int64_t nCalculatedStakeReward = GetProofOfStakeReward(nCoinAge, nFees);
  
          if (nStakeReward > nCalculatedStakeReward)
              return DoS(100, error("ConnectBlock() : coinstake pays too much(actual=%"PRId64" vs calculated=%"PRId64")", nStakeReward, nCalculatedStakeReward));
      }
  
      // ppcoin: track money supply and mint amount info
      pindex->nMint = nValueOut - nValueIn + nFees;
      pindex->nMoneySupply = (pindex->pprev? pindex->pprev->nMoneySupply : 0) + nValueOut - nValueIn;
      if (!txdb.WriteBlockIndex(CDiskBlockIndex(pindex)))
          return error("Connect() : WriteBlockIndex for pindex failed");
  
      if (fJustCheck)
          return true;
  
      // Write queued txindex changes
      for (map<uint256, CTxIndex>::iterator mi = mapQueuedChanges.begin(); mi != mapQueuedChanges.end(); ++mi)
      {
          if (!txdb.UpdateTxIndex((*mi).first, (*mi).second))
              return error("ConnectBlock() : UpdateTxIndex failed");
      }
  
      // Update block index on disk without changing it in memory.
      // The memory index structure will be changed after the db commits.
      if (pindex->pprev)
      {
          CDiskBlockIndex blockindexPrev(pindex->pprev);
          blockindexPrev.hashNext = pindex->GetBlockHash();
          if (!txdb.WriteBlockIndex(blockindexPrev))
              return error("ConnectBlock() : WriteBlockIndex failed");
      }
  
      // Watch for transactions paying to me
      BOOST_FOREACH(CTransaction& tx, vtx)
          SyncWithWallets(tx, this, true);
  
      return true;
  }
  
  bool static Reorganize(CTxDB& txdb, CBlockIndex* pindexNew)
  {
      printf("REORGANIZE\n");
  
      // Find the fork
      CBlockIndex* pfork = pindexBest;
      CBlockIndex* plonger = pindexNew;
      while (pfork != plonger)
      {
          while (plonger->nHeight > pfork->nHeight)
              if (!(plonger = plonger->pprev))
                  return error("Reorganize() : plonger->pprev is null");
          if (pfork == plonger)
              break;
          if (!(pfork = pfork->pprev))
              return error("Reorganize() : pfork->pprev is null");
      }
  
      // List of what to disconnect
      vector<CBlockIndex*> vDisconnect;
      for (CBlockIndex* pindex = pindexBest; pindex != pfork; pindex = pindex->pprev)
          vDisconnect.push_back(pindex);
  
      // List of what to connect
      vector<CBlockIndex*> vConnect;
      for (CBlockIndex* pindex = pindexNew; pindex != pfork; pindex = pindex->pprev)
          vConnect.push_back(pindex);
      reverse(vConnect.begin(), vConnect.end());
  
      printf("REORGANIZE: Disconnect %"PRIszu" blocks; %s..%s\n", vDisconnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexBest->GetBlockHash().ToString().substr(0,20).c_str());
      printf("REORGANIZE: Connect %"PRIszu" blocks; %s..%s\n", vConnect.size(), pfork->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->GetBlockHash().ToString().substr(0,20).c_str());
  
      // Disconnect shorter branch
      vector<CTransaction> vResurrect;
      BOOST_FOREACH(CBlockIndex* pindex, vDisconnect)
      {
          CBlock block;
          if (!block.ReadFromDisk(pindex))
              return error("Reorganize() : ReadFromDisk for disconnect failed");
          if (!block.DisconnectBlock(txdb, pindex))
              return error("Reorganize() : DisconnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
  
          // Queue memory transactions to resurrect
          BOOST_FOREACH(const CTransaction& tx, block.vtx)
              if (!(tx.IsCoinBase() || tx.IsCoinStake()))
                  vResurrect.push_back(tx);
      }
  
      // Connect longer branch
      vector<CTransaction> vDelete;
      for (unsigned int i = 0; i < vConnect.size(); i++)
      {
          CBlockIndex* pindex = vConnect[i];
          CBlock block;
          if (!block.ReadFromDisk(pindex))
              return error("Reorganize() : ReadFromDisk for connect failed");
          if (!block.ConnectBlock(txdb, pindex))
          {
              // Invalid block
              return error("Reorganize() : ConnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
          }
  
          // Queue memory transactions to delete
          BOOST_FOREACH(const CTransaction& tx, block.vtx)
              vDelete.push_back(tx);
      }
      if (!txdb.WriteHashBestChain(pindexNew->GetBlockHash()))
          return error("Reorganize() : WriteHashBestChain failed");
  
      // Make sure it's successfully written to disk before changing memory structure
      if (!txdb.TxnCommit())
          return error("Reorganize() : TxnCommit failed");
  
      // Disconnect shorter branch
      BOOST_FOREACH(CBlockIndex* pindex, vDisconnect)
          if (pindex->pprev)
              pindex->pprev->pnext = NULL;
  
      // Connect longer branch
      BOOST_FOREACH(CBlockIndex* pindex, vConnect)
          if (pindex->pprev)
              pindex->pprev->pnext = pindex;
  
      // Resurrect memory transactions that were in the disconnected branch
      BOOST_FOREACH(CTransaction& tx, vResurrect)
          tx.AcceptToMemoryPool(txdb, false);
  
      // Delete redundant memory transactions that are in the connected branch
      BOOST_FOREACH(CTransaction& tx, vDelete) {
          mempool.remove(tx);
          mempool.removeConflicts(tx);
      }
  
      printf("REORGANIZE: done\n");
  
      return true;
  }
  
  
  // Called from inside SetBestChain: attaches a block to the new best chain being built
  bool CBlock::SetBestChainInner(CTxDB& txdb, CBlockIndex *pindexNew)
  {
      uint256 hash = GetHash();
  
      // Adding to current best branch
      if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
      {
          txdb.TxnAbort();
          InvalidChainFound(pindexNew);
          return false;
      }
      if (!txdb.TxnCommit())
          return error("SetBestChain() : TxnCommit failed");
  
      // Add to current best branch
      pindexNew->pprev->pnext = pindexNew;
  
      // Delete redundant memory transactions
      BOOST_FOREACH(CTransaction& tx, vtx)
          mempool.remove(tx);
  
      return true;
  }
  
  bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
  {
      uint256 hash = GetHash();
  
      if (!txdb.TxnBegin())
          return error("SetBestChain() : TxnBegin failed");
  
      if (pindexGenesisBlock == NULL && hash == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet))
      {
          txdb.WriteHashBestChain(hash);
          if (!txdb.TxnCommit())
              return error("SetBestChain() : TxnCommit failed");
          pindexGenesisBlock = pindexNew;
      }
      else if (hashPrevBlock == hashBestChain)
      {
          if (!SetBestChainInner(txdb, pindexNew))
              return error("SetBestChain() : SetBestChainInner failed");
      }
      else
      {
          // the first block in the new chain that will cause it to become the new best chain
          CBlockIndex *pindexIntermediate = pindexNew;
  
          // list of blocks that need to be connected afterwards
          std::vector<CBlockIndex*> vpindexSecondary;
  
          // Reorganize is costly in terms of db load, as it works in a single db transaction.
          // Try to limit how much needs to be done inside
          while (pindexIntermediate->pprev && pindexIntermediate->pprev->nChainTrust > pindexBest->nChainTrust)
          {
              vpindexSecondary.push_back(pindexIntermediate);
              pindexIntermediate = pindexIntermediate->pprev;
          }
  
          if (!vpindexSecondary.empty())
              printf("Postponing %"PRIszu" reconnects\n", vpindexSecondary.size());
  
          // Switch to new best branch
          if (!Reorganize(txdb, pindexIntermediate))
          {
              txdb.TxnAbort();
              InvalidChainFound(pindexNew);
              return error("SetBestChain() : Reorganize failed");
          }
  
          // Connect further blocks
          BOOST_REVERSE_FOREACH(CBlockIndex *pindex, vpindexSecondary)
          {
              CBlock block;
              if (!block.ReadFromDisk(pindex))
              {
                  printf("SetBestChain() : ReadFromDisk failed\n");
                  break;
              }
              if (!txdb.TxnBegin()) {
                  printf("SetBestChain() : TxnBegin 2 failed\n");
                  break;
              }
              // errors now are not fatal, we still did a reorganisation to a new chain in a valid way
              if (!block.SetBestChainInner(txdb, pindex))
                  break;
          }
      }
  
      // Update best block in wallet (so we can detect restored wallets)
      bool fIsInitialDownload = IsInitialBlockDownload();
      if (!fIsInitialDownload)
      {
          const CBlockLocator locator(pindexNew);
          ::SetBestChain(locator);
      }
  
      // New best block
      hashBestChain = hash;
      pindexBest = pindexNew;
      pblockindexFBBHLast = NULL;
      nBestHeight = pindexBest->nHeight;
      nBestChainTrust = pindexNew->nChainTrust;
      nTimeBestReceived = GetTime();
      nTransactionsUpdated++;
  
      uint256 nBestBlockTrust = pindexBest->nHeight != 0 ? (pindexBest->nChainTrust - pindexBest->pprev->nChainTrust) : pindexBest->nChainTrust;
  
      printf("SetBestChain: new best=%s  height=%d  trust=%s  blocktrust=%"PRId64"  date=%s\n",
        hashBestChain.ToString().substr(0,20).c_str(), nBestHeight,
        CBigNum(nBestChainTrust).ToString().c_str(),
        nBestBlockTrust.Get64(),
        DateTimeStrFormat("%x %H:%M:%S", pindexBest->GetBlockTime()).c_str());
  
      // Check the version of the last 100 blocks to see if we need to upgrade:
      if (!fIsInitialDownload)
      {
          int nUpgraded = 0;
          const CBlockIndex* pindex = pindexBest;
          for (int i = 0; i < 100 && pindex != NULL; i++)
          {
              if (pindex->nVersion > CBlock::CURRENT_VERSION)
                  ++nUpgraded;
              pindex = pindex->pprev;
          }
          if (nUpgraded > 0)
              printf("SetBestChain: %d of last 100 blocks above version %d\n", nUpgraded, CBlock::CURRENT_VERSION);
          if (nUpgraded > 100/2)
              // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
              strMiscWarning = _("Warning: This version is obsolete, upgrade required!");
      }
  
      std::string strCmd = GetArg("-blocknotify", "");
  
      if (!fIsInitialDownload && !strCmd.empty())
      {
          boost::replace_all(strCmd, "%s", hashBestChain.GetHex());
          boost::thread t(runCommand, strCmd); // thread runs free
      }
  
      return true;
  }
  
  // ppcoin: total coin age spent in transaction, in the unit of coin-days.
  // Only those coins meeting minimum age requirement counts. As those
  // transactions not in main chain are not currently indexed so we
  // might not find out about their coin age. Older transactions are 
  // guaranteed to be in main chain by sync-checkpoint. This rule is
  // introduced to help nodes establish a consistent view of the coin
  // age (trust score) of competing branches.
  bool CTransaction::GetCoinAge(CTxDB& txdb, uint64_t& nCoinAge) const
  {
      CBigNum bnCentSecond = 0;  // coin age in the unit of cent-seconds
      nCoinAge = 0;
  
      if (IsCoinBase())
          return true;
  
      BOOST_FOREACH(const CTxIn& txin, vin)
      {
          // First try finding the previous transaction in database
          CTransaction txPrev;
          CTxIndex txindex;
          if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex))
              continue;  // previous transaction not in main chain
          if (nTime < txPrev.nTime)
              return false;  // Transaction timestamp violation
  
          // Read block header
          CBlock block;
          if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
              return false; // unable to read block of previous transaction
          if (block.GetBlockTime() + (pindexBest->nHeight < HARD_FORK_DIFF_FIX ? nStakeMinAge : nStakeMinAge_2) > nTime)
              continue; // only count coins meeting min age requirement
  
          int64_t nValueIn = txPrev.vout[txin.prevout.n].nValue;
          bnCentSecond += CBigNum(nValueIn) * (nTime-txPrev.nTime) / CENT;
  
          if (fDebug && GetBoolArg("-printcoinage"))
              printf("coin age nValueIn=%"PRId64" nTimeDiff=%d bnCentSecond=%s\n", nValueIn, nTime - txPrev.nTime, bnCentSecond.ToString().c_str());
      }
  
      CBigNum bnCoinDay = bnCentSecond * CENT / (24 * 60 * 60);
      if (fDebug && GetBoolArg("-printcoinage"))
          printf("coin age bnCoinDay=%s\n", bnCoinDay.ToString().c_str());
      nCoinAge = bnCoinDay.getuint64();
      return true;
  }
  
  // ppcoin: total coin age spent in block, in the unit of coin-days.
  bool CBlock::GetCoinAge(uint64_t& nCoinAge) const
  {
      nCoinAge = 0;
  
      CTxDB txdb("r");
      BOOST_FOREACH(const CTransaction& tx, vtx)
      {
          uint64_t nTxCoinAge;
          if (tx.GetCoinAge(txdb, nTxCoinAge))
              nCoinAge += nTxCoinAge;
          else
              return false;
      }
  
      if (nCoinAge == 0) // block coin age minimum 1 coin-day
          nCoinAge = 1;
      if (fDebug && GetBoolArg("-printcoinage"))
          printf("block coin age total nCoinDays=%"PRId64"\n", nCoinAge);
      return true;
  }
  
  bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos, const uint256& hashProofOfStake)
  {
      // Check for duplicate
      uint256 hash = GetHash();
      if (mapBlockIndex.count(hash))
          return error("AddToBlockIndex() : %s already exists", hash.ToString().substr(0,20).c_str());
  
      // Construct new block index object
      CBlockIndex* pindexNew = new CBlockIndex(nFile, nBlockPos, *this);
      if (!pindexNew)
          return error("AddToBlockIndex() : new CBlockIndex failed");
      pindexNew->phashBlock = &hash;
      map<uint256, CBlockIndex*>::iterator miPrev = mapBlockIndex.find(hashPrevBlock);
      if (miPrev != mapBlockIndex.end())
      {
          pindexNew->pprev = (*miPrev).second;
          pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
      }
  
      // ppcoin: compute chain trust score
      pindexNew->nChainTrust = (pindexNew->pprev ? pindexNew->pprev->nChainTrust : 0) + pindexNew->GetBlockTrust();
  
      // ppcoin: compute stake entropy bit for stake modifier
      if (!pindexNew->SetStakeEntropyBit(GetStakeEntropyBit()))
          return error("AddToBlockIndex() : SetStakeEntropyBit() failed");
  
      // ppcoin: record proof-of-stake hash value
      pindexNew->hashProofOfStake = hashProofOfStake;
  
      // ppcoin: compute stake modifier
      uint64_t nStakeModifier = 0;
      bool fGeneratedStakeModifier = false;
      if (!ComputeNextStakeModifier(pindexNew->pprev, nStakeModifier, fGeneratedStakeModifier))
          return error("AddToBlockIndex() : ComputeNextStakeModifier() failed");
      pindexNew->SetStakeModifier(nStakeModifier, fGeneratedStakeModifier);
      pindexNew->nStakeModifierChecksum = GetStakeModifierChecksum(pindexNew);
  //    if (!CheckStakeModifierCheckpoints(pindexNew->nHeight, pindexNew->nStakeModifierChecksum))
  //        return error("AddToBlockIndex() : Rejected by stake modifier checkpoint height=%d, modifier=0x%016"PRIx64, pindexNew->nHeight, nStakeModifier);
  
      // Add to mapBlockIndex
      map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
      if (pindexNew->IsProofOfStake())
          setStakeSeen.insert(make_pair(pindexNew->prevoutStake, pindexNew->nStakeTime));
      pindexNew->phashBlock = &((*mi).first);
  
      // Write to disk block index
      CTxDB txdb;
      if (!txdb.TxnBegin())
          return false;
      txdb.WriteBlockIndex(CDiskBlockIndex(pindexNew));
      if (!txdb.TxnCommit())
          return false;
  
      // New best
      if (pindexNew->nChainTrust > nBestChainTrust)
          if (!SetBestChain(txdb, pindexNew))
              return false;
  
      if (pindexNew == pindexBest)
      {
          // Notify UI to display prev block's coinbase if it was ours
          static uint256 hashPrevBestCoinBase;
          UpdatedTransaction(hashPrevBestCoinBase);
          hashPrevBestCoinBase = vtx[0].GetHash();
      }
  
      uiInterface.NotifyBlocksChanged();
      return true;
  }
  
  
  
  
  bool CBlock::CheckBlock(bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig) const
  {
      // These are checks that are independent of context
      // that can be verified before saving an orphan block.
  
      // Size limits
      if (vtx.empty() || vtx.size() > MAX_BLOCK_SIZE || ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
          return DoS(100, error("CheckBlock() : size limits failed"));
  
      // Check proof of work matches claimed amount
      if (fCheckPOW && IsProofOfWork() && !CheckProofOfWork(GetHash(), nBits))
          return DoS(50, error("CheckBlock() : proof of work failed"));
  
      // Check timestamp
      if (GetBlockTime() > FutureDrift(GetAdjustedTime()))
          return error("CheckBlock() : block timestamp too far in the future");
  
      // First transaction must be coinbase, the rest must not be
      if (vtx.empty() || !vtx[0].IsCoinBase())
          return DoS(100, error("CheckBlock() : first tx is not coinbase"));
      for (unsigned int i = 1; i < vtx.size(); i++)
          if (vtx[i].IsCoinBase())
              return DoS(100, error("CheckBlock() : more than one coinbase"));
  
      // Check coinbase timestamp
      if (GetBlockTime() > FutureDrift((int64_t)vtx[0].nTime))
          return DoS(50, error("CheckBlock() : coinbase timestamp is too early"));
  
      if (IsProofOfStake())
      {
          // Coinbase output should be empty if proof-of-stake block
          if (vtx[0].vout.size() != 1 || !vtx[0].vout[0].IsEmpty())
              return DoS(100, error("CheckBlock() : coinbase output not empty for proof-of-stake block"));
  
          // Second transaction must be coinstake, the rest must not be
          if (vtx.empty() || !vtx[1].IsCoinStake())
              return DoS(100, error("CheckBlock() : second tx is not coinstake"));
          for (unsigned int i = 2; i < vtx.size(); i++)
              if (vtx[i].IsCoinStake())
                  return DoS(100, error("CheckBlock() : more than one coinstake"));
  
          // Check coinstake timestamp
          if (!CheckCoinStakeTimestamp(GetBlockTime(), (int64_t)vtx[1].nTime))
              return DoS(50, error("CheckBlock() : coinstake timestamp violation nTimeBlock=%"PRId64" nTimeTx=%u", GetBlockTime(), vtx[1].nTime));
  
          // NovaCoin: check proof-of-stake block signature
          if (fCheckSig && !CheckBlockSignature())
              return DoS(100, error("CheckBlock() : bad proof-of-stake block signature"));
      }
  
      // Check transactions
      BOOST_FOREACH(const CTransaction& tx, vtx)
      {
          if (!tx.CheckTransaction())
              return DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));
  
          // ppcoin: check transaction timestamp
          if (GetBlockTime() < (int64_t)tx.nTime)
              return DoS(50, error("CheckBlock() : block timestamp earlier than transaction timestamp"));
      }
  
      // Check for duplicate txids. This is caught by ConnectInputs(),
      // but catching it earlier avoids a potential DoS attack:
      set<uint256> uniqueTx;
      BOOST_FOREACH(const CTransaction& tx, vtx)
      {
          uniqueTx.insert(tx.GetHash());
      }
      if (uniqueTx.size() != vtx.size())
          return DoS(100, error("CheckBlock() : duplicate transaction"));
  
      unsigned int nSigOps = 0;
      BOOST_FOREACH(const CTransaction& tx, vtx)
      {
          nSigOps += tx.GetLegacySigOpCount();
      }
      if (nSigOps > MAX_BLOCK_SIGOPS)
          return DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"));
  
      // Check merkle root
      if (fCheckMerkleRoot && hashMerkleRoot != BuildMerkleTree())
          return DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"));
  
  
      return true;
  }
  
  bool CBlock::AcceptBlock()
  {
      // Check for duplicate
      uint256 hash = GetHash();
      if (mapBlockIndex.count(hash))
          return error("AcceptBlock() : block already in mapBlockIndex");
  
      // Get prev block index
      map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashPrevBlock);
      if (mi == mapBlockIndex.end())
          return DoS(10, error("AcceptBlock() : prev block not found"));
      CBlockIndex* pindexPrev = (*mi).second;
      int nHeight = pindexPrev->nHeight+1;
  
      if (IsProofOfWork() && nHeight > LAST_POW_BLOCK)
          return DoS(100, error("AcceptBlock() : reject proof-of-work at height %d", nHeight));
  
      if (IsProofOfStake() && nHeight < MODIFIER_INTERVAL_SWITCH)
          return DoS(100, error("AcceptBlock() : reject proof-of-stake at height %d", nHeight));
  
      // Check proof-of-work or proof-of-stake
      if (nBits != GetNextTargetRequired(pindexPrev, IsProofOfStake()))
          return DoS(100, error("AcceptBlock() : incorrect %s", IsProofOfWork() ? "proof-of-work" : "proof-of-stake"));
  
      // Check timestamp against prev
      if (GetBlockTime() <= pindexPrev->GetPastTimeLimit() || FutureDrift(GetBlockTime()) < pindexPrev->GetBlockTime())
          return error("AcceptBlock() : block's timestamp is too early");
  
      // Check that all transactions are finalized
      BOOST_FOREACH(const CTransaction& tx, vtx)
          if (!tx.IsFinal(nHeight, GetBlockTime()))
              return DoS(10, error("AcceptBlock() : contains a non-final transaction"));
  
      // Check that the block chain matches the known block chain up to a checkpoint
      if (!Checkpoints::CheckHardened(nHeight, hash))
          return DoS(100, error("AcceptBlock() : rejected by hardened checkpoint lock-in at %d", nHeight));
  
      // Verify hash target and signature of coinstake tx
      uint256 hashProofOfStake = 0, targetProofOfStake = 0;
      if (IsProofOfStake())
      {
          if (!CheckProofOfStake(vtx[1], nBits, hashProofOfStake, targetProofOfStake))
          {
  	    printf("WARNING: AcceptBlock(): check proof-of-stake failed for block %s\n", hash.ToString().c_str());
              return false; // do not error here as we expect this during initial block download
          }
      }
  
      bool cpSatisfies = Checkpoints::CheckSync(hash, pindexPrev);
  
      // Check that the block satisfies synchronized checkpoint
      if (CheckpointsMode == Checkpoints::STRICT && !cpSatisfies)
          return error("AcceptBlock() : rejected by synchronized checkpoint");
  
      if (CheckpointsMode == Checkpoints::ADVISORY && !cpSatisfies)
          strMiscWarning = _("WARNING: syncronized checkpoint violation detected, but skipped!");
  
      // Write block to history file
      if (!CheckDiskSpace(::GetSerializeSize(*this, SER_DISK, CLIENT_VERSION)))
          return error("AcceptBlock() : out of disk space");
      unsigned int nFile = -1;
      unsigned int nBlockPos = 0;
      if (!WriteToDisk(nFile, nBlockPos))
          return error("AcceptBlock() : WriteToDisk failed");
      if (!AddToBlockIndex(nFile, nBlockPos, hashProofOfStake))
          return error("AcceptBlock() : AddToBlockIndex failed");
  
      // Relay inventory, but don't relay old inventory during initial block download
      int nBlockEstimate = Checkpoints::GetTotalBlocksEstimate();
      if (hashBestChain == hash)
      {
          LOCK(cs_vNodes);
          BOOST_FOREACH(CNode* pnode, vNodes)
              if (nBestHeight > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : nBlockEstimate))
                  pnode->PushInventory(CInv(MSG_BLOCK, hash));
      }
  
      // ppcoin: check pending sync-checkpoint
      Checkpoints::AcceptPendingSyncCheckpoint();
  
      return true;
  }
  
  uint256 CBlockIndex::GetBlockTrust() const
  {
      CBigNum bnTarget;
      bnTarget.SetCompact(nBits);
  
      if (bnTarget <= 0)
          return 0;
  
      return ((CBigNum(1)<<256) / (bnTarget+1)).getuint256();
  }
  
  bool CBlockIndex::IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned int nRequired, unsigned int nToCheck)
  {
      unsigned int nFound = 0;
      for (unsigned int i = 0; i < nToCheck && nFound < nRequired && pstart != NULL; i++)
      {
          if (pstart->nVersion >= minVersion)
              ++nFound;
          pstart = pstart->pprev;
      }
      return (nFound >= nRequired);
  }
  
  bool ProcessBlock(CNode* pfrom, CBlock* pblock)
  {
      // Check for duplicate
      uint256 hash = pblock->GetHash();
      if (mapBlockIndex.count(hash))
          return error("ProcessBlock() : already have block %d %s", mapBlockIndex[hash]->nHeight, hash.ToString().substr(0,20).c_str());
      if (mapOrphanBlocks.count(hash))
          return error("ProcessBlock() : already have block (orphan) %s", hash.ToString().substr(0,20).c_str());
  
      // ppcoin: check proof-of-stake
      // Limited duplicity on stake: prevents block flood attack
      // Duplicate stake allowed only when there is orphan child block
      if (pblock->IsProofOfStake() && setStakeSeen.count(pblock->GetProofOfStake()) && !mapOrphanBlocksByPrev.count(hash) && !Checkpoints::WantedByPendingSyncCheckpoint(hash))
          return error("ProcessBlock() : duplicate proof-of-stake (%s, %d) for block %s", pblock->GetProofOfStake().first.ToString().c_str(), pblock->GetProofOfStake().second, hash.ToString().c_str());
  
      // Preliminary checks
      if (!pblock->CheckBlock())
          return error("ProcessBlock() : CheckBlock FAILED");
  
      CBlockIndex* pcheckpoint = Checkpoints::GetLastSyncCheckpoint();
      if (pcheckpoint && pblock->hashPrevBlock != hashBestChain && !Checkpoints::WantedByPendingSyncCheckpoint(hash))
      {
          // Extra checks to prevent "fill up memory by spamming with bogus blocks"
          int64_t deltaTime = pblock->GetBlockTime() - pcheckpoint->nTime;
          CBigNum bnNewBlock;
          bnNewBlock.SetCompact(pblock->nBits);
          CBigNum bnRequired;
  
          if (pblock->IsProofOfStake())
              bnRequired.SetCompact(ComputeMinStake(GetLastBlockIndex(pcheckpoint, true)->nBits, deltaTime, pblock->nTime));
          else
              bnRequired.SetCompact(ComputeMinWork(GetLastBlockIndex(pcheckpoint, false)->nBits, deltaTime));
  
          if (bnNewBlock > bnRequired)
          {
              if (pfrom)
                  pfrom->Misbehaving(100);
              return error("ProcessBlock() : block with too little %s", pblock->IsProofOfStake()? "proof-of-stake" : "proof-of-work");
          }
      }
  
      // ppcoin: ask for pending sync-checkpoint if any
      if (!IsInitialBlockDownload())
          Checkpoints::AskForPendingSyncCheckpoint(pfrom);
  
      // If don't already have its previous block, shunt it off to holding area until we get it
      if (!mapBlockIndex.count(pblock->hashPrevBlock))
      {
          printf("ProcessBlock: ORPHAN BLOCK, prev=%s\n", pblock->hashPrevBlock.ToString().substr(0,20).c_str());
          CBlock* pblock2 = new CBlock(*pblock);
          // ppcoin: check proof-of-stake
          if (pblock2->IsProofOfStake())
          {
              // Limited duplicity on stake: prevents block flood attack
              // Duplicate stake allowed only when there is orphan child block
              if (setStakeSeenOrphan.count(pblock2->GetProofOfStake()) && !mapOrphanBlocksByPrev.count(hash) && !Checkpoints::WantedByPendingSyncCheckpoint(hash))
                  return error("ProcessBlock() : duplicate proof-of-stake (%s, %d) for orphan block %s", pblock2->GetProofOfStake().first.ToString().c_str(), pblock2->GetProofOfStake().second, hash.ToString().c_str());
              else
                  setStakeSeenOrphan.insert(pblock2->GetProofOfStake());
          }
          mapOrphanBlocks.insert(make_pair(hash, pblock2));
          mapOrphanBlocksByPrev.insert(make_pair(pblock2->hashPrevBlock, pblock2));
  
          // Ask this guy to fill in what we're missing
          if (pfrom)
          {
              pfrom->PushGetBlocks(pindexBest, GetOrphanRoot(pblock2));
              // ppcoin: getblocks may not obtain the ancestor block rejected
              // earlier by duplicate-stake check so we ask for it again directly
              if (!IsInitialBlockDownload())
                  pfrom->AskFor(CInv(MSG_BLOCK, WantedByOrphan(pblock2)));
          }
          return true;
      }
  
      // Store to disk
      if (!pblock->AcceptBlock())
          return error("ProcessBlock() : AcceptBlock FAILED");
  
      // Recursively process any orphan blocks that depended on this one
      vector<uint256> vWorkQueue;
      vWorkQueue.push_back(hash);
      for (unsigned int i = 0; i < vWorkQueue.size(); i++)
      {
          uint256 hashPrev = vWorkQueue[i];
          for (multimap<uint256, CBlock*>::iterator mi = mapOrphanBlocksByPrev.lower_bound(hashPrev);
               mi != mapOrphanBlocksByPrev.upper_bound(hashPrev);
               ++mi)
          {
              CBlock* pblockOrphan = (*mi).second;
              if (pblockOrphan->AcceptBlock())
                  vWorkQueue.push_back(pblockOrphan->GetHash());
              mapOrphanBlocks.erase(pblockOrphan->GetHash());
              setStakeSeenOrphan.erase(pblockOrphan->GetProofOfStake());
              delete pblockOrphan;
          }
          mapOrphanBlocksByPrev.erase(hashPrev);
      }
  
      printf("ProcessBlock: ACCEPTED\n");
  
      // ppcoin: if responsible for sync-checkpoint send it
      if (pfrom && !CSyncCheckpoint::strMasterPrivKey.empty())
          Checkpoints::SendSyncCheckpoint(Checkpoints::AutoSelectSyncCheckpoint());
  
      return true;
  }
  
  // bumbacoin2: attempt to generate suitable proof-of-stake
  bool CBlock::SignBlock(CWallet& wallet, int64_t nFees)
  {
      // if we are trying to sign
      //    something except proof-of-stake block template
      if (!vtx[0].vout[0].IsEmpty())
          return false;
  
      // if we are trying to sign
      //    a complete proof-of-stake block
      if (IsProofOfStake())
          return true;
  
      static int64_t nLastCoinStakeSearchTime = GetAdjustedTime(); // startup timestamp
  
      CKey key;
      CTransaction txCoinStake;
      int64_t nSearchTime = txCoinStake.nTime; // search to current time
  
      if (nSearchTime > nLastCoinStakeSearchTime)
      {
          if (wallet.CreateCoinStake(wallet, nBits, nSearchTime-nLastCoinStakeSearchTime, nFees, txCoinStake, key))
          {
              if (txCoinStake.nTime >= max(pindexBest->GetPastTimeLimit()+1, PastDrift(pindexBest->GetBlockTime())))
              {
                  // make sure coinstake would meet timestamp protocol
                  //    as it would be the same as the block timestamp
                  vtx[0].nTime = nTime = txCoinStake.nTime;
                  nTime = max(pindexBest->GetPastTimeLimit()+1, GetMaxTransactionTime());
                  nTime = max(GetBlockTime(), PastDrift(pindexBest->GetBlockTime()));
  
                  // we have to make sure that we have no future timestamps in
                  //    our transactions set
                  for (vector<CTransaction>::iterator it = vtx.begin(); it != vtx.end();)
                      if (it->nTime > nTime) { it = vtx.erase(it); } else { ++it; }
  
                  vtx.insert(vtx.begin() + 1, txCoinStake);
                  hashMerkleRoot = BuildMerkleTree();
  
                  // append a signature to our block
                  return key.Sign(GetHash(), vchBlockSig);
              }
          }
          nLastCoinStakeSearchInterval = nSearchTime - nLastCoinStakeSearchTime;
          nLastCoinStakeSearchTime = nSearchTime;
      }
  
      return false;
  }
  
  bool CBlock::CheckBlockSignature() const
  {
      if (IsProofOfWork())
          return vchBlockSig.empty();
  
      vector<valtype> vSolutions;
      txnouttype whichType;
  
      const CTxOut& txout = vtx[1].vout[1];
  
      if (!Solver(txout.scriptPubKey, whichType, vSolutions))
          return false;
  
      if (whichType == TX_PUBKEY)
      {
          valtype& vchPubKey = vSolutions[0];
          CKey key;
          if (!key.SetPubKey(vchPubKey))
              return false;
          if (vchBlockSig.empty())
              return false;
          return key.Verify(GetHash(), vchBlockSig);
      }
  
      return false;
  }
  
  bool CheckDiskSpace(uint64_t nAdditionalBytes)
  {
      uint64_t nFreeBytesAvailable = filesystem::space(GetDataDir()).available;
  
      // Check for nMinDiskSpace bytes (currently 50MB)
      if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
      {
          fShutdown = true;
          string strMessage = _("Warning: Disk space is low!");
          strMiscWarning = strMessage;
          printf("*** %s\n", strMessage.c_str());
          uiInterface.ThreadSafeMessageBox(strMessage, "bumbacoin2", CClientUIInterface::OK | CClientUIInterface::ICON_EXCLAMATION | CClientUIInterface::MODAL);
          StartShutdown();
          return false;
      }
      return true;
  }
  
  static filesystem::path BlockFilePath(unsigned int nFile)
  {
      string strBlockFn = strprintf("blk%04u.dat", nFile);
      return GetDataDir() / strBlockFn;
  }
  
  FILE* OpenBlockFile(unsigned int nFile, unsigned int nBlockPos, const char* pszMode)
  {
      if ((nFile < 1) || (nFile == (unsigned int) -1))
          return NULL;
      FILE* file = fopen(BlockFilePath(nFile).string().c_str(), pszMode);
      if (!file)
          return NULL;
      if (nBlockPos != 0 && !strchr(pszMode, 'a') && !strchr(pszMode, 'w'))
      {
          if (fseek(file, nBlockPos, SEEK_SET) != 0)
          {
              fclose(file);
              return NULL;
          }
      }
      return file;
  }
  
  static unsigned int nCurrentBlockFile = 1;
  
  FILE* AppendBlockFile(unsigned int& nFileRet)
  {
      nFileRet = 0;
      while (true)
      {
          FILE* file = OpenBlockFile(nCurrentBlockFile, 0, "ab");
          if (!file)
              return NULL;
          if (fseek(file, 0, SEEK_END) != 0)
              return NULL;
          // FAT32 file size max 4GB, fseek and ftell max 2GB, so we must stay under 2GB
          if (ftell(file) < (long)(0x7F000000 - MAX_SIZE))
          {
              nFileRet = nCurrentBlockFile;
              return file;
          }
          fclose(file);
          nCurrentBlockFile++;
      }
  }
  
  bool LoadBlockIndex(bool fAllowNew)
  {
      CBigNum bnTrustedModulus;
  
      if (fTestNet)
      {
          bnProofOfWorkLimit = bnProofOfWorkLimitTestNet; // PoW base target is fixed in testnet
          nStakeMinAge = 1 * 60; // test net min age is 20 min
          nStakeMinAge_2 = 1 * 90; // test net min age is 20 min
          nCoinbaseMaturity = 10; // test maturity is 10 blocks
      }
  
      //
      // Load block index
      //
      CTxDB txdb("cr+");
      if (!txdb.LoadBlockIndex())
          return false;
  
      //
      // Init with genesis block
      //
      if (mapBlockIndex.empty())
      {
          if (!fAllowNew)
              return false;
  
          const char* pszTimestamp = "Bumba Bumba Coin";
          CTransaction txNew;
          txNew.nTime = 1412502251;
          txNew.vin.resize(1);
          txNew.vout.resize(1);
          txNew.vin[0].scriptSig = CScript() << 0 << CBigNum(42) << vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
          txNew.vout[0].SetEmpty();
          CBlock block;
          block.vtx.push_back(txNew);
          block.hashPrevBlock = 0;
          block.hashMerkleRoot = block.BuildMerkleTree();
          block.nVersion = 1;
          block.nTime    = 1412502251;
          block.nBits    = bnProofOfWorkLimit.GetCompact();
          block.nNonce   = 729236;
  		if(fTestNet)
          {
              block.nNonce   = 0;
              block.nTime	   = 1547414304;
          }
          if (false  && (block.GetHash() != hashGenesisBlock)) {
  
          // This will figure out a valid hash and Nonce if you're
          // creating a different genesis block:
              uint256 hashTarget = CBigNum().SetCompact(block.nBits).getuint256();
              while (block.GetHash() > hashTarget)
                 {
                     ++block.nNonce;
                     if (block.nNonce == 0)
                     {
                         printf("NONCE WRAPPED, incrementing time");
                         ++block.nTime;
                     }
                 }
          }
          block.print();
          printf("block.GetHash() == %s\n", block.GetHash().ToString().c_str());
          printf("block.hashMerkleRoot == %s\n", block.hashMerkleRoot.ToString().c_str());
          printf("block.nTime = %u \n", block.nTime);
          printf("block.nNonce = %u \n", block.nNonce);
  
          //// debug print
  //        assert(block.hashMerkleRoot == uint256("0x30bc1694525feefebbe7066c9f138aa20f135846a51f3189608ada17dbed97d6"));
          block.print();
          assert(block.GetHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
  
          // Start new block file
          unsigned int nFile;
          unsigned int nBlockPos;
          if (!block.WriteToDisk(nFile, nBlockPos))
              return error("LoadBlockIndex() : writing genesis block to disk failed");
          if (!block.AddToBlockIndex(nFile, nBlockPos, 0))
              return error("LoadBlockIndex() : genesis block not accepted");
  
          // ppcoin: initialize synchronized checkpoint
          if (!Checkpoints::WriteSyncCheckpoint((!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet)))
              return error("LoadBlockIndex() : failed to init sync checkpoint");
      }
  
      string strPubKey = "";
  
      // if checkpoint master key changed must reset sync-checkpoint
      if (!txdb.ReadCheckpointPubKey(strPubKey) || strPubKey != CSyncCheckpoint::strMasterPubKey)
      {
          // write checkpoint master key to db
          txdb.TxnBegin();
          if (!txdb.WriteCheckpointPubKey(CSyncCheckpoint::strMasterPubKey))
              return error("LoadBlockIndex() : failed to write new checkpoint master key to db");
          if (!txdb.TxnCommit())
              return error("LoadBlockIndex() : failed to commit new checkpoint master key to db");
          if ((!fTestNet) && !Checkpoints::ResetSyncCheckpoint())
              return error("LoadBlockIndex() : failed to reset sync-checkpoint");
      }
  
      return true;
  }
  
  
  
  void PrintBlockTree()
  {
      // pre-compute tree structure
      map<CBlockIndex*, vector<CBlockIndex*> > mapNext;
      for (map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.begin(); mi != mapBlockIndex.end(); ++mi)
      {
          CBlockIndex* pindex = (*mi).second;
          mapNext[pindex->pprev].push_back(pindex);
          // test
          //while (rand() % 3 == 0)
          //    mapNext[pindex->pprev].push_back(pindex);
      }
  
      vector<pair<int, CBlockIndex*> > vStack;
      vStack.push_back(make_pair(0, pindexGenesisBlock));
  
      int nPrevCol = 0;
      while (!vStack.empty())
      {
          int nCol = vStack.back().first;
          CBlockIndex* pindex = vStack.back().second;
          vStack.pop_back();
  
          // print split or gap
          if (nCol > nPrevCol)
          {
              for (int i = 0; i < nCol-1; i++)
                  printf("| ");
              printf("|\\\n");
          }
          else if (nCol < nPrevCol)
          {
              for (int i = 0; i < nCol; i++)
                  printf("| ");
              printf("|\n");
         }
          nPrevCol = nCol;
  
          // print columns
          for (int i = 0; i < nCol; i++)
              printf("| ");
  
          // print item
          CBlock block;
          block.ReadFromDisk(pindex);
          printf("%d (%u,%u) %s  %08x  %s  mint %7s  tx %"PRIszu"",
              pindex->nHeight,
              pindex->nFile,
              pindex->nBlockPos,
              block.GetHash().ToString().c_str(),
              block.nBits,
              DateTimeStrFormat("%x %H:%M:%S", block.GetBlockTime()).c_str(),
              FormatMoney(pindex->nMint).c_str(),
              block.vtx.size());
  
          PrintWallets(block);
  
          // put the main time-chain first
          vector<CBlockIndex*>& vNext = mapNext[pindex];
          for (unsigned int i = 0; i < vNext.size(); i++)
          {
              if (vNext[i]->pnext)
              {
                  swap(vNext[0], vNext[i]);
                  break;
              }
          }
  
          // iterate children
          for (unsigned int i = 0; i < vNext.size(); i++)
              vStack.push_back(make_pair(nCol+i, vNext[i]));
      }
  }
  
  bool LoadExternalBlockFile(FILE* fileIn)
  {
      int64_t nStart = GetTimeMillis();
  
      int nLoaded = 0;
      {
          LOCK(cs_main);
          try {
              CAutoFile blkdat(fileIn, SER_DISK, CLIENT_VERSION);
              unsigned int nPos = 0;
              while (nPos != (unsigned int)-1 && blkdat.good() && !fRequestShutdown)
              {
                  unsigned char pchData[65536];
                  do {
                      fseek(blkdat, nPos, SEEK_SET);
                      int nRead = fread(pchData, 1, sizeof(pchData), blkdat);
                      if (nRead <= 8)
                      {
                          nPos = (unsigned int)-1;
                          break;
                      }
                      void* nFind = memchr(pchData, pchMessageStart[0], nRead+1-sizeof(pchMessageStart));
                      if (nFind)
                      {
                          if (memcmp(nFind, pchMessageStart, sizeof(pchMessageStart))==0)
                          {
                              nPos += ((unsigned char*)nFind - pchData) + sizeof(pchMessageStart);
                              break;
                          }
                          nPos += ((unsigned char*)nFind - pchData) + 1;
                      }
                      else
                          nPos += sizeof(pchData) - sizeof(pchMessageStart) + 1;
                  } while(!fRequestShutdown);
                  if (nPos == (unsigned int)-1)
                      break;
                  fseek(blkdat, nPos, SEEK_SET);
                  unsigned int nSize;
                  blkdat >> nSize;
                  if (nSize > 0 && nSize <= MAX_BLOCK_SIZE)
                  {
                      CBlock block;
                      blkdat >> block;
                      if (ProcessBlock(NULL,&block))
                      {
                          nLoaded++;
                          nPos += 4 + nSize;
                      }
                  }
              }
          }
          catch (std::exception &e) {
              printf("%s() : Deserialize or I/O error caught during load\n",
                     __PRETTY_FUNCTION__);
          }
      }
      printf("Loaded %i blocks from external file in %"PRId64"ms\n", nLoaded, GetTimeMillis() - nStart);
      return nLoaded > 0;
  }
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // CAlert
  //
  
  extern map<uint256, CAlert> mapAlerts;
  extern CCriticalSection cs_mapAlerts;
  
  string GetWarnings(string strFor)
  {
      int nPriority = 0;
      string strStatusBar;
      string strRPC;
  
      if (GetBoolArg("-testsafemode"))
          strRPC = "test";
  
      // Misc warnings like out of disk space and clock is wrong
      if (strMiscWarning != "")
      {
          nPriority = 1000;
          strStatusBar = strMiscWarning;
      }
  
      // if detected invalid checkpoint enter safe mode
      if (Checkpoints::hashInvalidCheckpoint != 0)
      {
          nPriority = 3000;
          strStatusBar = strRPC = _("WARNING: Invalid checkpoint found! Displayed transactions may not be correct! You may need to upgrade, or notify developers.");
      }
  
      // Alerts
      {
          LOCK(cs_mapAlerts);
          BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
          {
              const CAlert& alert = item.second;
              if (alert.AppliesToMe() && alert.nPriority > nPriority)
              {
                  nPriority = alert.nPriority;
                  strStatusBar = alert.strStatusBar;
                  if (nPriority > 1000)
                      strRPC = strStatusBar;
              }
          }
      }
  
      if (strFor == "statusbar")
          return strStatusBar;
      else if (strFor == "rpc")
          return strRPC;
      assert(!"GetWarnings() : invalid parameter");
      return "error";
  }
  
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // Messages
  //
  
  
  bool static AlreadyHave(CTxDB& txdb, const CInv& inv)
  {
      switch (inv.type)
      {
      case MSG_TX:
          {
          bool txInMap = false;
              {
              LOCK(mempool.cs);
              txInMap = (mempool.exists(inv.hash));
              }
          return txInMap ||
                 mapOrphanTransactions.count(inv.hash) ||
                 txdb.ContainsTx(inv.hash);
          }
  
      case MSG_BLOCK:
          return mapBlockIndex.count(inv.hash) ||
                 mapOrphanBlocks.count(inv.hash);
      }
      // Don't know what it is, just say we already got one
      return true;
  }
  
  
  
  
  // The message start string is designed to be unlikely to occur in normal data.
  // The characters are rarely used upper ASCII, not valid as UTF-8, and produce
  // a large 4-byte int at any alignment.
  unsigned char pchMessageStart[4] = { 0xb1, 0xc0, 0xd2, 0xe3 };
  
  bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
  {
      static map<CService, CPubKey> mapReuseKey;
      RandAddSeedPerfmon();
      if (fDebug)
          printf("received: %s (%"PRIszu" bytes)\n", strCommand.c_str(), vRecv.size());
      if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
      {
          printf("dropmessagestest DROPPING RECV MESSAGE\n");
          return true;
      }
  
      if (strCommand == "version")
      {
          // Each connection can only send one version message
          if (pfrom->nVersion != 0)
          {
              pfrom->Misbehaving(1);
              return false;
          }
  
          int64_t nTime;
          CAddress addrMe;
          CAddress addrFrom;
          uint64_t nNonce = 1;
          vRecv >> pfrom->nVersion >> pfrom->nServices >> nTime >> addrMe;
  		if (pfrom->nVersion < (pindexBest->nHeight < HARD_FORK_DIFF_FIX ? MIN_PROTO_VERSION : MIN_PROTO_VERSION_FORK))
          {
              printf("partner %s using obsolete version %i; disconnecting\n", pfrom->addr.ToString().c_str(), pfrom->nVersion);
              pfrom->fDisconnect = true;
              return false;
          }
  
          if (pfrom->nVersion == 10300)
              pfrom->nVersion = 300;
          if (!vRecv.empty())
              vRecv >> addrFrom >> nNonce;
          if (!vRecv.empty())
              vRecv >> pfrom->strSubVer;
          if (!vRecv.empty())
              vRecv >> pfrom->nStartingHeight;
  
          if (pfrom->fInbound && addrMe.IsRoutable())
          {
              pfrom->addrLocal = addrMe;
              SeenLocal(addrMe);
          }
  
          // Disconnect if we connected to ourself
          if (nNonce == nLocalHostNonce && nNonce > 1)
          {
              printf("connected to self at %s, disconnecting\n", pfrom->addr.ToString().c_str());
              pfrom->fDisconnect = true;
              return true;
          }
  
          // record my external IP reported by peer
          if (addrFrom.IsRoutable() && addrMe.IsRoutable())
              addrSeenByPeer = addrMe;
  
          // Be shy and don't send version until we hear
          if (pfrom->fInbound)
              pfrom->PushVersion();
  
          pfrom->fClient = !(pfrom->nServices & NODE_NETWORK);
  
          if (GetBoolArg("-synctime", true))
              AddTimeData(pfrom->addr, nTime);
  
          // Change version
          pfrom->PushMessage("verack");
          pfrom->vSend.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
  
          if (!pfrom->fInbound)
          {
              // Advertise our address
              if (!fNoListen && !IsInitialBlockDownload())
              {
                  CAddress addr = GetLocalAddress(&pfrom->addr);
                  if (addr.IsRoutable())
                      pfrom->PushAddress(addr);
              }
  
              // Get recent addresses
              if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
              {
                  pfrom->PushMessage("getaddr");
                  pfrom->fGetAddr = true;
              }
              addrman.Good(pfrom->addr);
          } else {
              if (((CNetAddr)pfrom->addr) == (CNetAddr)addrFrom)
              {
                  addrman.Add(addrFrom, addrFrom);
                  addrman.Good(addrFrom);
              }
          }
  
          // Ask the first connected node for block updates
          static int nAskedForBlocks = 0;
          if (!pfrom->fClient && !pfrom->fOneShot &&
              (pfrom->nStartingHeight > (nBestHeight - 144)) &&
              (pfrom->nVersion < NOBLKS_VERSION_START ||
               pfrom->nVersion >= NOBLKS_VERSION_END) &&
               (nAskedForBlocks < 1 || vNodes.size() <= 1))
          {
              nAskedForBlocks++;
              pfrom->PushGetBlocks(pindexBest, uint256(0));
          }
  
          // Relay alerts
          {
              LOCK(cs_mapAlerts);
              BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
                  item.second.RelayTo(pfrom);
          }
  
          // Relay sync-checkpoint
          {
              LOCK(Checkpoints::cs_hashSyncCheckpoint);
              if (!Checkpoints::checkpointMessage.IsNull())
                  Checkpoints::checkpointMessage.RelayTo(pfrom);
          }
  
          pfrom->fSuccessfullyConnected = true;
  
          printf("receive version message: version %d, blocks=%d, us=%s, them=%s, peer=%s\n", pfrom->nVersion, pfrom->nStartingHeight, addrMe.ToString().c_str(), addrFrom.ToString().c_str(), pfrom->addr.ToString().c_str());
  
          cPeerBlockCounts.input(pfrom->nStartingHeight);
  
          // ppcoin: ask for pending sync-checkpoint if any
          if (!IsInitialBlockDownload())
              Checkpoints::AskForPendingSyncCheckpoint(pfrom);
      }
  
  
      else if (pfrom->nVersion == 0)
      {
          // Must have a version message before anything else
          pfrom->Misbehaving(1);
          return false;
      }
  
  
      else if (strCommand == "verack")
      {
          pfrom->vRecv.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
      }
  
  
      else if (strCommand == "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)
          {
              pfrom->Misbehaving(20);
              return error("message addr size() = %"PRIszu"", vAddr.size());
          }
  
          // Store the new addresses
          vector<CAddress> vAddrOk;
          int64_t nNow = GetAdjustedTime();
          int64_t nSince = nNow - 10 * 60;
          BOOST_FOREACH(CAddress& addr, vAddr)
          {
              if (fShutdown)
                  return true;
              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 setAddrKnowns of the chosen nodes prevent repeats
                      static uint256 hashSalt;
                      if (hashSalt == 0)
                          hashSalt = GetRandHash();
                      uint64_t hashAddr = addr.GetHash();
                      uint256 hashRand = hashSalt ^ (hashAddr<<32) ^ ((GetTime()+hashAddr)/(24*60*60));
                      hashRand = Hash(BEGIN(hashRand), END(hashRand));
                      multimap<uint256, CNode*> mapMix;
                      BOOST_FOREACH(CNode* pnode, vNodes)
                      {
                          if (pnode->nVersion < CADDR_TIME_VERSION)
                              continue;
                          unsigned int nPointer;
                          memcpy(&nPointer, &pnode, sizeof(nPointer));
                          uint256 hashKey = hashRand ^ nPointer;
                          hashKey = Hash(BEGIN(hashKey), END(hashKey));
                          mapMix.insert(make_pair(hashKey, pnode));
                      }
                      int nRelayNodes = fReachable ? 2 : 1; // limited relaying of addresses outside our network(s)
                      for (multimap<uint256, 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 == "inv")
      {
          vector<CInv> vInv;
          vRecv >> vInv;
          if (vInv.size() > MAX_INV_SZ)
          {
              pfrom->Misbehaving(20);
              return error("message inv size() = %"PRIszu"", vInv.size());
          }
  
          // find last block in inv vector
          unsigned int nLastBlock = (unsigned int)(-1);
          for (unsigned int nInv = 0; nInv < vInv.size(); nInv++) {
              if (vInv[vInv.size() - 1 - nInv].type == MSG_BLOCK) {
                  nLastBlock = vInv.size() - 1 - nInv;
                  break;
              }
          }
          CTxDB txdb("r");
          for (unsigned int nInv = 0; nInv < vInv.size(); nInv++)
          {
              const CInv &inv = vInv[nInv];
  
              if (fShutdown)
                  return true;
              pfrom->AddInventoryKnown(inv);
  
              bool fAlreadyHave = AlreadyHave(txdb, inv);
              if (fDebug)
                  printf("  got inventory: %s  %s\n", inv.ToString().c_str(), fAlreadyHave ? "have" : "new");
  
              if (!fAlreadyHave)
                  pfrom->AskFor(inv);
              else if (inv.type == MSG_BLOCK && mapOrphanBlocks.count(inv.hash)) {
                  pfrom->PushGetBlocks(pindexBest, GetOrphanRoot(mapOrphanBlocks[inv.hash]));
              } else if (nInv == nLastBlock) {
                  // In case we are on a very long side-chain, it is possible that we already have
                  // the last block in an inv bundle sent in response to getblocks. Try to detect
                  // this situation and push another getblocks to continue.
                  pfrom->PushGetBlocks(mapBlockIndex[inv.hash], uint256(0));
                  if (fDebug)
                      printf("force request: %s\n", inv.ToString().c_str());
              }
  
              // Track requests for our stuff
              Inventory(inv.hash);
          }
      }
  
  
      else if (strCommand == "getdata")
      {
          vector<CInv> vInv;
          vRecv >> vInv;
          if (vInv.size() > MAX_INV_SZ)
          {
              pfrom->Misbehaving(20);
              return error("message getdata size() = %"PRIszu"", vInv.size());
          }
  
          if (fDebugNet || (vInv.size() != 1))
              printf("received getdata (%"PRIszu" invsz)\n", vInv.size());
  
          BOOST_FOREACH(const CInv& inv, vInv)
          {
              if (fShutdown)
                  return true;
              if (fDebugNet || (vInv.size() == 1))
                  printf("received getdata for: %s\n", inv.ToString().c_str());
  
              if (inv.type == MSG_BLOCK)
              {
                  // Send block from disk
                  map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(inv.hash);
                  if (mi != mapBlockIndex.end())
                  {
                      CBlock block;
                      block.ReadFromDisk((*mi).second);
                      pfrom->PushMessage("block", block);
  
                      // Trigger them to send a getblocks request for the next batch of inventory
                      if (inv.hash == pfrom->hashContinue)
                      {
                          // ppcoin: send latest proof-of-work block to allow the
                          // download node to accept as orphan (proof-of-stake 
                          // block might be rejected by stake connection check)
                          vector<CInv> vInv;
                          vInv.push_back(CInv(MSG_BLOCK, GetLastBlockIndex(pindexBest, false)->GetBlockHash()));
                          pfrom->PushMessage("inv", vInv);
                          pfrom->hashContinue = 0;
                      }
                  }
              }
              else if (inv.IsKnownType())
              {
                  // Send stream from relay memory
                  bool pushed = false;
                  {
                      LOCK(cs_mapRelay);
                      map<CInv, CDataStream>::iterator mi = mapRelay.find(inv);
                      if (mi != mapRelay.end()) {
                          pfrom->PushMessage(inv.GetCommand(), (*mi).second);
                          pushed = true;
                      }
                  }
                  if (!pushed && inv.type == MSG_TX) {
                      LOCK(mempool.cs);
                      if (mempool.exists(inv.hash)) {
                          CTransaction tx = mempool.lookup(inv.hash);
                          CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
                          ss.reserve(1000);
                          ss << tx;
                          pfrom->PushMessage("tx", ss);
                      }
                  }
              }
  
              // Track requests for our stuff
              Inventory(inv.hash);
          }
      }
  
  
      else if (strCommand == "getblocks")
      {
          CBlockLocator locator;
          uint256 hashStop;
          vRecv >> locator >> hashStop;
  
          // Find the last block the caller has in the main chain
          CBlockIndex* pindex = locator.GetBlockIndex();
  
          // Send the rest of the chain
          if (pindex)
              pindex = pindex->pnext;
          int nLimit = 500;
          printf("getblocks %d to %s limit %d\n", (pindex ? pindex->nHeight : -1), hashStop.ToString().substr(0,20).c_str(), nLimit);
          for (; pindex; pindex = pindex->pnext)
          {
              if (pindex->GetBlockHash() == hashStop)
              {
                  printf("  getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str());
                  // ppcoin: tell downloading node about the latest block if it's
                  // without risk being rejected due to stake connection check
                  if (hashStop != hashBestChain && pindex->GetBlockTime() + (pindexBest->nHeight < HARD_FORK_DIFF_FIX ? nStakeMinAge : nStakeMinAge_2) > pindexBest->GetBlockTime())
                      pfrom->PushInventory(CInv(MSG_BLOCK, hashBestChain));
                  break;
              }
              pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
              if (--nLimit <= 0)
              {
                  // When this block is requested, we'll send an inv that'll make them
                  // getblocks the next batch of inventory.
                  printf("  getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString().substr(0,20).c_str());
                  pfrom->hashContinue = pindex->GetBlockHash();
                  break;
              }
          }
      }
      else if (strCommand == "checkpoint")
      {
          CSyncCheckpoint checkpoint;
          vRecv >> checkpoint;
  
          if (checkpoint.ProcessSyncCheckpoint(pfrom))
          {
              // Relay
              pfrom->hashCheckpointKnown = checkpoint.hashCheckpoint;
              LOCK(cs_vNodes);
              BOOST_FOREACH(CNode* pnode, vNodes)
                  checkpoint.RelayTo(pnode);
          }
      }
  
      else if (strCommand == "getheaders")
      {
          CBlockLocator locator;
          uint256 hashStop;
          vRecv >> locator >> hashStop;
  
          CBlockIndex* pindex = NULL;
          if (locator.IsNull())
          {
              // If locator is null, return the hashStop block
              map<uint256, CBlockIndex*>::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 = locator.GetBlockIndex();
              if (pindex)
                  pindex = pindex->pnext;
          }
  
          vector<CBlock> vHeaders;
          int nLimit = 2000;
          printf("getheaders %d to %s\n", (pindex ? pindex->nHeight : -1), hashStop.ToString().substr(0,20).c_str());
          for (; pindex; pindex = pindex->pnext)
          {
              vHeaders.push_back(pindex->GetBlockHeader());
              if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop)
                  break;
          }
          pfrom->PushMessage("headers", vHeaders);
      }
  
  
      else if (strCommand == "tx")
      {
          vector<uint256> vWorkQueue;
          vector<uint256> vEraseQueue;
          CDataStream vMsg(vRecv);
          CTxDB txdb("r");
          CTransaction tx;
          vRecv >> tx;
  
          CInv inv(MSG_TX, tx.GetHash());
          pfrom->AddInventoryKnown(inv);
  
          bool fMissingInputs = false;
          if (tx.AcceptToMemoryPool(txdb, true, &fMissingInputs))
          {
              SyncWithWallets(tx, NULL, true);
              RelayTransaction(tx, inv.hash);
              mapAlreadyAskedFor.erase(inv);
              vWorkQueue.push_back(inv.hash);
              vEraseQueue.push_back(inv.hash);
  
              // Recursively process any orphan transactions that depended on this one
              for (unsigned int i = 0; i < vWorkQueue.size(); i++)
              {
                  uint256 hashPrev = vWorkQueue[i];
                  for (set<uint256>::iterator mi = mapOrphanTransactionsByPrev[hashPrev].begin();
                       mi != mapOrphanTransactionsByPrev[hashPrev].end();
                       ++mi)
                  {
                      const uint256& orphanTxHash = *mi;
                      CTransaction& orphanTx = mapOrphanTransactions[orphanTxHash];
                      bool fMissingInputs2 = false;
  
                      if (orphanTx.AcceptToMemoryPool(txdb, true, &fMissingInputs2))
                      {
                          printf("   accepted orphan tx %s\n", orphanTxHash.ToString().substr(0,10).c_str());
                          SyncWithWallets(tx, NULL, true);
                          RelayTransaction(orphanTx, orphanTxHash);
                          mapAlreadyAskedFor.erase(CInv(MSG_TX, orphanTxHash));
                          vWorkQueue.push_back(orphanTxHash);
                          vEraseQueue.push_back(orphanTxHash);
                      }
                      else if (!fMissingInputs2)
                      {
                          // invalid orphan
                          vEraseQueue.push_back(orphanTxHash);
                          printf("   removed invalid orphan tx %s\n", orphanTxHash.ToString().substr(0,10).c_str());
                      }
                  }
              }
  
              BOOST_FOREACH(uint256 hash, vEraseQueue)
                  EraseOrphanTx(hash);
          }
          else if (fMissingInputs)
          {
              AddOrphanTx(tx);
  
              // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
              unsigned int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
              if (nEvicted > 0)
                  printf("mapOrphan overflow, removed %u tx\n", nEvicted);
          }
          if (tx.nDoS) pfrom->Misbehaving(tx.nDoS);
      }
  
  
      else if (strCommand == "block")
      {
          CBlock block;
          vRecv >> block;
          uint256 hashBlock = block.GetHash();
  
          printf("received block %s\n", hashBlock.ToString().substr(0,20).c_str());
          // block.print();
  
          CInv inv(MSG_BLOCK, hashBlock);
          pfrom->AddInventoryKnown(inv);
  
          if (ProcessBlock(pfrom, &block))
              mapAlreadyAskedFor.erase(inv);
          if (block.nDoS) pfrom->Misbehaving(block.nDoS);
      }
  
  
      else if (strCommand == "getaddr")
      {
          // Don't return addresses older than nCutOff timestamp
          int64_t nCutOff = GetTime() - (nNodeLifespan * 24 * 60 * 60);
          pfrom->vAddrToSend.clear();
          vector<CAddress> vAddr = addrman.GetAddr();
          BOOST_FOREACH(const CAddress &addr, vAddr)
              if(addr.nTime > nCutOff)
                  pfrom->PushAddress(addr);
      }
  
  
      else if (strCommand == "mempool")
      {
          std::vector<uint256> vtxid;
          mempool.queryHashes(vtxid);
          vector<CInv> vInv;
          for (unsigned int i = 0; i < vtxid.size(); i++) {
              CInv inv(MSG_TX, vtxid[i]);
              vInv.push_back(inv);
              if (i == (MAX_INV_SZ - 1))
                      break;
          }
          if (vInv.size() > 0)
              pfrom->PushMessage("inv", vInv);
      }
  
  
      else if (strCommand == "checkorder")
      {
          uint256 hashReply;
          vRecv >> hashReply;
  
          if (!GetBoolArg("-allowreceivebyip"))
          {
              pfrom->PushMessage("reply", hashReply, (int)2, string(""));
              return true;
          }
  
          CWalletTx order;
          vRecv >> order;
  
          /// we have a chance to check the order here
  
          // Keep giving the same key to the same ip until they use it
          if (!mapReuseKey.count(pfrom->addr))
              pwalletMain->GetKeyFromPool(mapReuseKey[pfrom->addr], true);
  
          // Send back approval of order and pubkey to use
          CScript scriptPubKey;
          scriptPubKey << mapReuseKey[pfrom->addr] << OP_CHECKSIG;
          pfrom->PushMessage("reply", hashReply, (int)0, scriptPubKey);
      }
  
  
      else if (strCommand == "reply")
      {
          uint256 hashReply;
          vRecv >> hashReply;
  
          CRequestTracker tracker;
          {
              LOCK(pfrom->cs_mapRequests);
              map<uint256, CRequestTracker>::iterator mi = pfrom->mapRequests.find(hashReply);
              if (mi != pfrom->mapRequests.end())
              {
                  tracker = (*mi).second;
                  pfrom->mapRequests.erase(mi);
              }
          }
          if (!tracker.IsNull())
              tracker.fn(tracker.param1, vRecv);
      }
  
  
      else if (strCommand == "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("pong", nonce);
          }
      }
  
  
      else if (strCommand == "alert")
      {
          CAlert alert;
          vRecv >> alert;
  
          uint256 alertHash = alert.GetHash();
          if (pfrom->setKnown.count(alertHash) == 0)
          {
              if (alert.ProcessAlert())
              {
                  // Relay
                  pfrom->setKnown.insert(alertHash);
                  {
                      LOCK(cs_vNodes);
                      BOOST_FOREACH(CNode* pnode, vNodes)
                          alert.RelayTo(pnode);
                  }
              }
              else {
                  // Small DoS penalty so peers that send us lots of
                  // duplicate/expired/invalid-signature/whatever alerts
                  // eventually get banned.
                  // This isn't a Misbehaving(100) (immediate ban) because the
                  // peer might be an older or different implementation with
                  // a different signature key, etc.
                  pfrom->Misbehaving(10);
              }
          }
      }
  
  
      else
      {
          // Ignore unknown commands for extensibility
      }
  
  
      // Update the last seen time for this node's address
      if (pfrom->fNetworkNode)
          if (strCommand == "version" || strCommand == "addr" || strCommand == "inv" || strCommand == "getdata" || strCommand == "ping")
              AddressCurrentlyConnected(pfrom->addr);
  
  
      return true;
  }
  
  bool ProcessMessages(CNode* pfrom)
  {
      CDataStream& vRecv = pfrom->vRecv;
      if (vRecv.empty())
          return true;
      //if (fDebug)
      //    printf("ProcessMessages(%u bytes)\n", vRecv.size());
  
      //
      // Message format
      //  (4) message start
      //  (12) command
      //  (4) size
      //  (4) checksum
      //  (x) data
      //
  
      while (true)
      {
          // Don't bother if send buffer is too full to respond anyway
          if (pfrom->vSend.size() >= SendBufferSize())
              break;
  
          // Scan for message start
          CDataStream::iterator pstart = search(vRecv.begin(), vRecv.end(), BEGIN(pchMessageStart), END(pchMessageStart));
          int nHeaderSize = vRecv.GetSerializeSize(CMessageHeader());
          if (vRecv.end() - pstart < nHeaderSize)
          {
              if ((int)vRecv.size() > nHeaderSize)
              {
                  printf("\n\nPROCESSMESSAGE MESSAGESTART NOT FOUND\n\n");
                  vRecv.erase(vRecv.begin(), vRecv.end() - nHeaderSize);
              }
              break;
          }
          if (pstart - vRecv.begin() > 0)
              printf("\n\nPROCESSMESSAGE SKIPPED %"PRIpdd" BYTES\n\n", pstart - vRecv.begin());
          vRecv.erase(vRecv.begin(), pstart);
  
          // Read header
          vector<char> vHeaderSave(vRecv.begin(), vRecv.begin() + nHeaderSize);
          CMessageHeader hdr;
          vRecv >> hdr;
          if (!hdr.IsValid())
          {
              printf("\n\nPROCESSMESSAGE: ERRORS IN HEADER %s\n\n\n", hdr.GetCommand().c_str());
              continue;
          }
          string strCommand = hdr.GetCommand();
  
          // Message size
          unsigned int nMessageSize = hdr.nMessageSize;
          if (nMessageSize > MAX_SIZE)
          {
              printf("ProcessMessages(%s, %u bytes) : nMessageSize > MAX_SIZE\n", strCommand.c_str(), nMessageSize);
              continue;
          }
          if (nMessageSize > vRecv.size())
          {
              // Rewind and wait for rest of message
              vRecv.insert(vRecv.begin(), vHeaderSave.begin(), vHeaderSave.end());
              break;
          }
  
          // Checksum
          uint256 hash = Hash(vRecv.begin(), vRecv.begin() + nMessageSize);
          unsigned int nChecksum = 0;
          memcpy(&nChecksum, &hash, sizeof(nChecksum));
          if (nChecksum != hdr.nChecksum)
          {
              printf("ProcessMessages(%s, %u bytes) : CHECKSUM ERROR nChecksum=%08x hdr.nChecksum=%08x\n",
                 strCommand.c_str(), nMessageSize, nChecksum, hdr.nChecksum);
              continue;
          }
  
          // Copy message to its own buffer
          CDataStream vMsg(vRecv.begin(), vRecv.begin() + nMessageSize, vRecv.nType, vRecv.nVersion);
          vRecv.ignore(nMessageSize);
  
          // Process message
          bool fRet = false;
          try
          {
              {
                  LOCK(cs_main);
                  fRet = ProcessMessage(pfrom, strCommand, vMsg);
              }
              if (fShutdown)
                  return true;
          }
          catch (std::ios_base::failure& e)
          {
              if (strstr(e.what(), "end of data"))
              {
                  // Allow exceptions from under-length message on vRecv
                  printf("ProcessMessages(%s, %u bytes) : Exception '%s' caught, normally caused by a message being shorter than its stated length\n", strCommand.c_str(), nMessageSize, e.what());
              }
              else if (strstr(e.what(), "size too large"))
              {
                  // Allow exceptions from over-long size
                  printf("ProcessMessages(%s, %u bytes) : Exception '%s' caught\n", strCommand.c_str(), nMessageSize, e.what());
              }
              else
              {
                  PrintExceptionContinue(&e, "ProcessMessages()");
              }
          }
          catch (std::exception& e) {
              PrintExceptionContinue(&e, "ProcessMessages()");
          } catch (...) {
              PrintExceptionContinue(NULL, "ProcessMessages()");
          }
  
          if (!fRet)
              printf("ProcessMessage(%s, %u bytes) FAILED\n", strCommand.c_str(), nMessageSize);
      }
  
      vRecv.Compact();
      return true;
  }
  
  
  bool SendMessages(CNode* pto, bool fSendTrickle)
  {
      TRY_LOCK(cs_main, lockMain);
      if (lockMain) {
          // Don't send anything until we get their version message
          if (pto->nVersion == 0)
              return true;
  
          // Keep-alive ping. We send a nonce of zero because we don't use it anywhere
          // right now.
          if (pto->nLastSend && GetTime() - pto->nLastSend > 30 * 60 && pto->vSend.empty()) {
              uint64_t nonce = 0;
              if (pto->nVersion > BIP0031_VERSION)
                  pto->PushMessage("ping", nonce);
              else
                  pto->PushMessage("ping");
          }
  
          // Resend wallet transactions that haven't gotten in a block yet
          ResendWalletTransactions();
  
          // Address refresh broadcast
          static int64_t nLastRebroadcast;
          if (!IsInitialBlockDownload() && (GetTime() - nLastRebroadcast > 24 * 60 * 60))
          {
              {
                  LOCK(cs_vNodes);
                  BOOST_FOREACH(CNode* pnode, vNodes)
                  {
                      // Periodically clear setAddrKnown to allow refresh broadcasts
                      if (nLastRebroadcast)
                          pnode->setAddrKnown.clear();
  
                      // Rebroadcast our address
                      if (!fNoListen)
                      {
                          CAddress addr = GetLocalAddress(&pnode->addr);
                          if (addr.IsRoutable())
                              pnode->PushAddress(addr);
                      }
                  }
              }
              nLastRebroadcast = GetTime();
          }
  
          //
          // Message: addr
          //
          if (fSendTrickle)
          {
              vector<CAddress> vAddr;
              vAddr.reserve(pto->vAddrToSend.size());
              BOOST_FOREACH(const CAddress& addr, pto->vAddrToSend)
              {
                  // returns true if wasn't already contained in the set
                  if (pto->setAddrKnown.insert(addr).second)
                  {
                      vAddr.push_back(addr);
                      // receiver rejects addr messages larger than 1000
                      if (vAddr.size() >= 1000)
                      {
                          pto->PushMessage("addr", vAddr);
                          vAddr.clear();
                      }
                  }
              }
              pto->vAddrToSend.clear();
              if (!vAddr.empty())
                  pto->PushMessage("addr", vAddr);
          }
  
  
          //
          // Message: inventory
          //
          vector<CInv> vInv;
          vector<CInv> vInvWait;
          {
              LOCK(pto->cs_inventory);
              vInv.reserve(pto->vInventoryToSend.size());
              vInvWait.reserve(pto->vInventoryToSend.size());
              BOOST_FOREACH(const CInv& inv, pto->vInventoryToSend)
              {
                  if (pto->setInventoryKnown.count(inv))
                      continue;
  
                  // trickle out tx inv to protect privacy
                  if (inv.type == MSG_TX && !fSendTrickle)
                  {
                      // 1/4 of tx invs blast to all immediately
                      static uint256 hashSalt;
                      if (hashSalt == 0)
                          hashSalt = GetRandHash();
                      uint256 hashRand = inv.hash ^ hashSalt;
                      hashRand = Hash(BEGIN(hashRand), END(hashRand));
                      bool fTrickleWait = ((hashRand & 3) != 0);
  
                      // always trickle our own transactions
                      if (!fTrickleWait)
                      {
                          CWalletTx wtx;
                          if (GetTransaction(inv.hash, wtx))
                              if (wtx.fFromMe)
                                  fTrickleWait = true;
                      }
  
                      if (fTrickleWait)
                      {
                          vInvWait.push_back(inv);
                          continue;
                      }
                  }
  
                  // returns true if wasn't already contained in the set
                  if (pto->setInventoryKnown.insert(inv).second)
                  {
                      vInv.push_back(inv);
                      if (vInv.size() >= 1000)
                      {
                          pto->PushMessage("inv", vInv);
                          vInv.clear();
                      }
                  }
              }
              pto->vInventoryToSend = vInvWait;
          }
          if (!vInv.empty())
              pto->PushMessage("inv", vInv);
  
  
          //
          // Message: getdata
          //
          vector<CInv> vGetData;
          int64_t nNow = GetTime() * 1000000;
          CTxDB txdb("r");
          while (!pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
          {
              const CInv& inv = (*pto->mapAskFor.begin()).second;
              if (!AlreadyHave(txdb, inv))
              {
                  if (fDebugNet)
                      printf("sending getdata: %s\n", inv.ToString().c_str());
                  vGetData.push_back(inv);
                  if (vGetData.size() >= 1000)
                  {
                      pto->PushMessage("getdata", vGetData);
                      vGetData.clear();
                  }
                  mapAlreadyAskedFor[inv] = nNow;
              }
              pto->mapAskFor.erase(pto->mapAskFor.begin());
          }
          if (!vGetData.empty())
              pto->PushMessage("getdata", vGetData);
  
      }
      return true;
  }
  