// 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 "net.h"
#include "init.h"
#include "ui_interface.h"
#include "kernel.h"
#include "zerocoin/Zerocoin.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;
libzerocoin::Params* ZCParams;

CBigNum bnProofOfWorkLimit(~uint256(0) >> 20); // "standard" scrypt target limit for proof of work, results with 0,000244140625 proof-of-work difficulty
CBigNum bnProofOfStakeLegacyLimit(~uint256(0) >> 24); // proof of stake target limit from block #15000 and until 20 June 2013, results with 0,00390625 proof of stake difficulty
CBigNum bnProofOfStakeLimit(~uint256(0) >> 27); // proof of stake target limit since 20 June 2013, equal to 0.03125  proof of stake difficulty
CBigNum bnProofOfStakeHardLimit(~uint256(0) >> 30); // disabled temporarily, will be used in the future to fix minimal proof of stake difficulty at 0.25
uint256 nPoWBase = uint256("0x00000000ffff0000000000000000000000000000000000000000000000000000"); // difficulty-1 target

CBigNum bnProofOfWorkLimitTestNet(~uint256(0) >> 16);

unsigned int nStakeMinAge = 60 * 60 * 24 * 30; // 30 days as zero time weight
unsigned int nStakeMaxAge = 60 * 60 * 24 * 90; // 90 days as full weight
unsigned int nStakeTargetSpacing = 10 * 60; // 10-minute stakes spacing
unsigned int nModifierInterval = 6 * 60 * 60; // time to elapse before new modifier is computed

int nCoinbaseMaturity = 500;
CBlockIndex* pindexGenesisBlock = NULL;
int nBestHeight = -1;

uint256 nBestChainTrust = 0;
uint256 nBestInvalidTrust = 0;

uint256 hashBestChain = 0;
CBlockIndex* pindexBest = NULL;
int64 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, uint256> mapProofOfStake;

map<uint256, CTransaction> mapOrphanTransactions;
map<uint256, set<uint256> > mapOrphanTransactionsByPrev;

// Constant stuff for coinbase transactions we create:
CScript COINBASE_FLAGS;

const string strMessageMagic = "NovaCoin Signed Message:\n";

// Settings
int64 nTransactionFee = MIN_TX_FEE;
int64 nMinimumInputValue = MIN_TX_FEE;

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()
{
    BOOST_FOREACH(CWallet* pwallet, setpwalletRegistered)
        pwallet->ResendWalletTransactions();
}


//////////////////////////////////////////////////////////////////////////////
//
// CCoinsView implementations
//

bool CCoinsView::GetCoins(uint256 txid, CCoins &coins) { return false; }
bool CCoinsView::SetCoins(uint256 txid, const CCoins &coins) { return false; }
bool CCoinsView::HaveCoins(uint256 txid) { return false; }
CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }

CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
bool CCoinsViewBacked::GetCoins(uint256 txid, CCoins &coins) { return base->GetCoins(txid, coins); }
bool CCoinsViewBacked::SetCoins(uint256 txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
bool CCoinsViewBacked::HaveCoins(uint256 txid) { return base->HaveCoins(txid); }
CBlockIndex *CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
bool CCoinsViewBacked::SetBestBlock(CBlockIndex *pindex) { return base->SetBestBlock(pindex); }
void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }

bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return base->BatchWrite(mapCoins, pindex); }

CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), pindexTip(NULL) { }

bool CCoinsViewCache::GetCoins(uint256 txid, CCoins &coins) {
    if (cacheCoins.count(txid)) {
        coins = cacheCoins[txid];
        return true;
    }
    if (base->GetCoins(txid, coins)) {
        cacheCoins[txid] = coins;
        return true;
    }
    return false;
}

bool CCoinsViewCache::SetCoins(uint256 txid, const CCoins &coins) {
    cacheCoins[txid] = coins;
    return true;
}

bool CCoinsViewCache::HaveCoins(uint256 txid) {
    return cacheCoins.count(txid) || base->HaveCoins(txid);
}

CBlockIndex *CCoinsViewCache::GetBestBlock() {
    if (pindexTip == NULL)
        pindexTip = base->GetBestBlock();
    return pindexTip;
}

bool CCoinsViewCache::SetBestBlock(CBlockIndex *pindex) {
    pindexTip = pindex;
    return true;
}

bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
    for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
        cacheCoins[it->first] = it->second;
    pindexTip = pindex;
    return true;
}

bool CCoinsViewCache::Flush() {
    bool fOk = base->BatchWrite(cacheCoins, pindexTip);
    if (fOk)
        cacheCoins.clear();
    return fOk;
}

unsigned int CCoinsViewCache::GetCacheSize() {
    return cacheCoins.size();
}

/** CCoinsView that brings transactions from a memorypool into view.
    It does not check for spendings by memory pool transactions. */
CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }

bool CCoinsViewMemPool::GetCoins(uint256 txid, CCoins &coins) {
    if (base->GetCoins(txid, coins))
        return true;
    if (mempool.exists(txid)) {
        const CTransaction &tx = mempool.lookup(txid);
        coins = CCoins(tx, MEMPOOL_HEIGHT, -1);
        return true;
    }
    return false;
}

bool CCoinsViewMemPool::HaveCoins(uint256 txid) {
    return mempool.exists(txid) || base->HaveCoins(txid);
}

CCoinsViewCache *pcoinsTip = NULL;

//////////////////////////////////////////////////////////////////////////////
//
// 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
//

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;
    }
    BOOST_FOREACH(const CTxOut& txout, vout) {
        if (!::IsStandard(txout.scriptPubKey))
            return false;
        if (txout.nValue == 0)
            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(CCoinsView& 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, false, 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) {
            CCoins coins;
            if (pcoinsTip->GetCoins(GetHash(), coins)) {
                CBlockIndex *pindex = FindBlockByHeight(coins.nHeight);
                if (pindex) {
                    if (!blockTmp.ReadFromDisk(pindex))
                        return 0;
                    pblock = &blockTmp;
                }
            }
        }

        if (pblock) {
        // 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 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"));

        // Enforce minimum output amount for user transactions until 1 May 2014 04:00:00 GMT
        if (!fTestNet && !IsCoinBase() && !txout.IsEmpty() && nTime < OUTPUT_SWITCH_TIME && txout.nValue < MIN_TXOUT_AMOUNT)
            return DoS(100, error("CTransaction::CheckTransaction() : txout.nValue below minimum"));

        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 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
                              enum GetMinFee_mode mode, unsigned int nBytes) const
{
    // Base fee is either MIN_TX_FEE or MIN_RELAY_TX_FEE
    int64 nBaseFee = (mode == GMF_RELAY) ? MIN_RELAY_TX_FEE : MIN_TX_FEE;

    unsigned int nNewBlockSize = nBlockSize + nBytes;
    int64 nMinFee = (1 + (int64)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;
}

void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
{
    LOCK(cs);

    std::map<COutPoint, CInPoint>::iterator it = mapNextTx.lower_bound(COutPoint(hashTx, 0));

    // iterate over all COutPoints in mapNextTx whose hash equals the provided hashTx
    while (it != mapNextTx.end() && it->first.hash == hashTx) {
        coins.Spend(it->first.n); // and remove those outputs from coins
        it++;
    }
}

bool CTxMemPool::accept(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"));

    // 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)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");

    // is it already in the memory pool?
    uint256 hash = tx.GetHash();
    {
        LOCK(cs);
        if (mapTx.count(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)
    {
        CCoinsViewCache &view = *pcoinsTip;

        // do we already have it?
        if (view.HaveCoins(hash))
            return false;

        // do all inputs exist?
        BOOST_FOREACH(const CTxIn txin, tx.vin) {
            if (!view.HaveCoins(txin.prevout.hash)) {
                if (pfMissingInputs)
                    *pfMissingInputs = true;
                return false;
            }
        }

        // Check for non-standard pay-to-script-hash in inputs
        if (!tx.AreInputsStandard(view) && !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 nFees = tx.GetValueIn(view)-tx.GetValueOut();
        unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);

        // Don't accept it if it can't get into a block
        int64 txMinFee = tx.GetMinFee(1000, false, GMF_RELAY, nSize);
        if (nFees < txMinFee)
            return error("CTxMemPool::accept() : not enough fees %s, %"PRI64d" < %"PRI64d,
                         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 nLastTime;
            int64 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.CheckInputs(view, CS_ALWAYS, true, 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(bool fCheckInputs, bool* pfMissingInputs)
{
    return mempool.accept(*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(CTransaction &tx)
{
    // Remove transaction from memory pool
    {
        LOCK(cs);
        uint256 hash = tx.GetHash();
        if (mapTx.count(hash))
        {
            BOOST_FOREACH(const CTxIn& txin, tx.vin)
                mapNextTx.erase(txin.prevout);
            mapTx.erase(hash);
            nTransactionsUpdated++;
        }
    }
    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::GetDepthInMainChain(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::GetBlocksToMaturity() const
{
    if (!(IsCoinBase() || IsCoinStake()))
        return 0;
    return max(0, (nCoinbaseMaturity+20) - GetDepthInMainChain());
}


bool CMerkleTx::AcceptToMemoryPool(bool fCheckInputs)
{
    if (fClient)
    {
        if (!IsInMainChain() && !ClientCheckInputs())
            return false;
        return CTransaction::AcceptToMemoryPool(false);
    }
    else
    {
        return CTransaction::AcceptToMemoryPool(fCheckInputs);
    }
}

bool CWalletTx::AcceptWalletTransaction(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) && pcoinsTip->HaveCoins(hash))
                    tx.AcceptToMemoryPool(fCheckInputs);
            }
        }
        return AcceptToMemoryPool(fCheckInputs);
    }
    return false;
}

// Return transaction in tx, and if it was found inside a block, its hash is placed in hashBlock
bool GetTransaction(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock, bool fAllowSlow)
{
    CBlockIndex *pindexSlow = NULL;
    {
        LOCK(cs_main);
        {
            LOCK(mempool.cs);
            if (mempool.exists(hash))
            {
                txOut = mempool.lookup(hash);
                return true;
            }
        }

        if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
            int nHeight = -1;
            {
                CCoinsViewCache &view = *pcoinsTip;
                CCoins coins;
                if (view.GetCoins(hash, coins))
                    nHeight = coins.nHeight;
            }
            if (nHeight > 0)
                pindexSlow = FindBlockByHeight(nHeight);
        }
    }

    if (pindexSlow) {
        CBlock block;
        if (block.ReadFromDisk(pindexSlow)) {
            BOOST_FOREACH(const CTransaction &tx, block.vtx) {
                if (tx.GetHash() == hash) {
                    txOut = tx;
                    hashBlock = pindexSlow->GetBlockHash();
                    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->GetBlockPos(), 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;
}

// select stake target limit according to hard-coded conditions
CBigNum inline GetProofOfStakeLimit(int nHeight, unsigned int nTime)
{
    if(fTestNet) // separate proof of stake target limit for testnet
        return bnProofOfStakeLimit;
    if(nTime > TARGETS_SWITCH_TIME) // 27 bits since 20 July 2013
        return bnProofOfStakeLimit;
    if(nHeight + 1 > 15000) // 24 bits since block 15000
        return bnProofOfStakeLegacyLimit;
    if(nHeight + 1 > 14060) // 31 bits since block 14060 until 15000
        return bnProofOfStakeHardLimit;

    return bnProofOfWorkLimit; // return bnProofOfWorkLimit of none matched
}

// miner's coin base reward based on nBits
int64 GetProofOfWorkReward(unsigned int nBits)
{
    CBigNum bnSubsidyLimit = MAX_MINT_PROOF_OF_WORK;

    CBigNum bnTarget;
    bnTarget.SetCompact(nBits);
    CBigNum bnTargetLimit = bnProofOfWorkLimit;
    bnTargetLimit.SetCompact(bnTargetLimit.GetCompact());

    // NovaCoin: subsidy is cut in half every 64x multiply of PoW difficulty
    // A reasonably continuous curve is used to avoid shock to market
    // (nSubsidyLimit / nSubsidy) ** 6 == bnProofOfWorkLimit / bnTarget
    //
    // Human readable form:
    //
    // nSubsidy = 100 / (diff ^ 1/6)
    CBigNum bnLowerBound = CENT;
    CBigNum bnUpperBound = bnSubsidyLimit;
    while (bnLowerBound + CENT <= bnUpperBound)
    {
        CBigNum bnMidValue = (bnLowerBound + bnUpperBound) / 2;
        if (fDebug && GetBoolArg("-printcreation"))
            printf("GetProofOfWorkReward() : lower=%"PRI64d" upper=%"PRI64d" mid=%"PRI64d"\n", bnLowerBound.getuint64(), bnUpperBound.getuint64(), bnMidValue.getuint64());
        if (bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnTargetLimit > bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnTarget)
            bnUpperBound = bnMidValue;
        else
            bnLowerBound = bnMidValue;
    }

    int64 nSubsidy = bnUpperBound.getuint64();

    nSubsidy = (nSubsidy / CENT) * CENT;
    if (fDebug && GetBoolArg("-printcreation"))
        printf("GetProofOfWorkReward() : create=%s nBits=0x%08x nSubsidy=%"PRI64d"\n", FormatMoney(nSubsidy).c_str(), nBits, nSubsidy);

    return min(nSubsidy, MAX_MINT_PROOF_OF_WORK);
}

// miner's coin stake reward based on nBits and coin age spent (coin-days)
int64 GetProofOfStakeReward(int64 nCoinAge, unsigned int nBits, unsigned int nTime, bool bCoinYearOnly)
{
    int64 nRewardCoinYear, nSubsidy, nSubsidyLimit = 10 * COIN;

    if(fTestNet || nTime > STAKE_SWITCH_TIME)
    {
        // Stage 2 of emission process is PoS-based. It will be active on mainNet since 20 Jun 2013.

        CBigNum bnRewardCoinYearLimit = MAX_MINT_PROOF_OF_STAKE; // Base stake mint rate, 100% year interest
        CBigNum bnTarget;
        bnTarget.SetCompact(nBits);
        CBigNum bnTargetLimit = GetProofOfStakeLimit(0, nTime);
        bnTargetLimit.SetCompact(bnTargetLimit.GetCompact());

        // NovaCoin: A reasonably continuous curve is used to avoid shock to market

        CBigNum bnLowerBound = 1 * CENT, // Lower interest bound is 1% per year
            bnUpperBound = bnRewardCoinYearLimit, // Upper interest bound is 100% per year
            bnMidPart, bnRewardPart;

        while (bnLowerBound + CENT <= bnUpperBound)
        {
            CBigNum bnMidValue = (bnLowerBound + bnUpperBound) / 2;
            if (fDebug && GetBoolArg("-printcreation"))
                printf("GetProofOfStakeReward() : lower=%"PRI64d" upper=%"PRI64d" mid=%"PRI64d"\n", bnLowerBound.getuint64(), bnUpperBound.getuint64(), bnMidValue.getuint64());

            if(!fTestNet && nTime < STAKECURVE_SWITCH_TIME)
            {
                //
                // Until 20 Oct 2013: reward for coin-year is cut in half every 64x multiply of PoS difficulty
                //
                // (nRewardCoinYearLimit / nRewardCoinYear) ** 6 == bnProofOfStakeLimit / bnTarget
                //
                // Human readable form: nRewardCoinYear = 1 / (posdiff ^ 1/6)
                //

                bnMidPart = bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue;
                bnRewardPart = bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit;
            }
            else
            {
                //
                // Since 20 Oct 2013: reward for coin-year is cut in half every 8x multiply of PoS difficulty
                //
                // (nRewardCoinYearLimit / nRewardCoinYear) ** 3 == bnProofOfStakeLimit / bnTarget
                //
                // Human readable form: nRewardCoinYear = 1 / (posdiff ^ 1/3)
                //

                bnMidPart = bnMidValue * bnMidValue * bnMidValue;
                bnRewardPart = bnRewardCoinYearLimit * bnRewardCoinYearLimit * bnRewardCoinYearLimit;
            }

            if (bnMidPart * bnTargetLimit > bnRewardPart * bnTarget)
                bnUpperBound = bnMidValue;
            else
                bnLowerBound = bnMidValue;
        }

        nRewardCoinYear = bnUpperBound.getuint64();
        nRewardCoinYear = min((nRewardCoinYear / CENT) * CENT, MAX_MINT_PROOF_OF_STAKE);
    }
    else
    {
        // Old creation amount per coin-year, 5% fixed stake mint rate
        nRewardCoinYear = 5 * CENT;
    }

    if(bCoinYearOnly)
        return nRewardCoinYear;

    nSubsidy = nCoinAge * nRewardCoinYear * 33 / (365 * 33 + 8);

    // Set reasonable reward limit for large inputs since 20 Oct 2013
    //
    // This will stimulate large holders to use smaller inputs, that's good for the network protection
    if(fTestNet || STAKECURVE_SWITCH_TIME < nTime)
    {
        if (fDebug && GetBoolArg("-printcreation") && nSubsidyLimit < nSubsidy)
            printf("GetProofOfStakeReward(): %s is greater than %s, coinstake reward will be truncated\n", FormatMoney(nSubsidy).c_str(), FormatMoney(nSubsidyLimit).c_str());

        nSubsidy = min(nSubsidy, nSubsidyLimit);
    }

    if (fDebug && GetBoolArg("-printcreation"))
        printf("GetProofOfStakeReward(): create=%s nCoinAge=%"PRI64d" nBits=%d\n", FormatMoney(nSubsidy).c_str(), nCoinAge, nBits);
    return nSubsidy;
}

static const int64 nTargetTimespan = 7 * 24 * 60 * 60;  // one week

// get proof of work blocks max spacing according to hard-coded conditions
int64 inline GetTargetSpacingWorkMax(int nHeight, unsigned int nTime)
{
    if(nTime > TARGETS_SWITCH_TIME)
        return 3 * nStakeTargetSpacing; // 30 minutes on mainNet since 20 Jul 2013 00:00:00

    if(fTestNet)
        return 3 * nStakeTargetSpacing; // 15 minutes on testNet

    return 12 * nStakeTargetSpacing; // 2 hours otherwise
}

//
// maximum nBits value could possible be required nTime after
//
unsigned int ComputeMaxBits(CBigNum bnTargetLimit, unsigned int nBase, int64 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 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 nTime, unsigned int nBlockTime)
{
    return ComputeMaxBits(GetProofOfStakeLimit(0, nBlockTime), 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;
}

unsigned int GetNextTargetRequired(const CBlockIndex* pindexLast, bool fProofOfStake)
{
    CBigNum bnTargetLimit = !fProofOfStake ? bnProofOfWorkLimit : GetProofOfStakeLimit(pindexLast->nHeight, pindexLast->nTime);

    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 nActualSpacing = pindexPrev->GetBlockTime() - pindexPrevPrev->GetBlockTime();

    // ppcoin: target change every block
    // ppcoin: retarget with exponential moving toward target spacing
    CBigNum bnNew;
    bnNew.SetCompact(pindexPrev->nBits);
    int64 nTargetSpacing = fProofOfStake? nStakeTargetSpacing : min(GetTargetSpacingWorkMax(pindexLast->nHeight, pindexLast->nTime), (int64) nStakeTargetSpacing * (1 + pindexLast->nHeight - pindexPrev->nHeight));
    int64 nInterval = nTargetTimespan / nTargetSpacing;
    bnNew *= ((nInterval - 1) * nTargetSpacing + nActualSpacing + nActualSpacing);
    bnNew /= ((nInterval + 1) * nTargetSpacing);

    if (bnNew > bnTargetLimit)
        bnNew = bnTargetLimit;

    return bnNew.GetCompact();
}

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 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;
        CChainDB().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=%"PRI64d"  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=%"PRI64d"  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());
}


CTxOut CTransaction::GetOutputFor(const CTxIn& input, CCoinsView& view)
{
    CCoins coins;
    if (!view.GetCoins(input.prevout.hash, coins))
        throw std::runtime_error("CTransaction::GetOutputFor() : prevout.hash not found");

    if (input.prevout.n >= coins.vout.size())
        throw std::runtime_error("CTransaction::GetOutputFor() : prevout.n out of range or already spent");

    const CTxOut &out = coins.vout[input.prevout.n];
    if (out.IsNull())
        throw std::runtime_error("CTransaction::GetOutputFor() : already spent");

    return out;
}

int64 CTransaction::GetValueIn(CCoinsView& inputs) const
{
    if (IsCoinBase())
        return 0;

    int64 nResult = 0;
    for (unsigned int i = 0; i < vin.size(); i++)
    {
        nResult += GetOutputFor(vin[i], inputs).nValue;
    }
    return nResult;
}

unsigned int CTransaction::GetP2SHSigOpCount(CCoinsView& inputs) const
{
    if (IsCoinBase())
        return 0;

    unsigned int nSigOps = 0;
    for (unsigned int i = 0; i < vin.size(); i++)
    {
        CTxOut prevout = GetOutputFor(vin[i], inputs);
        if (prevout.scriptPubKey.IsPayToScriptHash())
            nSigOps += prevout.scriptPubKey.GetSigOpCount(vin[i].scriptSig);
    }
    return nSigOps;
}

bool CTransaction::UpdateCoins(CCoinsView &inputs, CTxUndo &txundo, int nHeight, unsigned int nTimeStamp) const
{
    uint256 hash = GetHash();

    // mark inputs spent
    if (!IsCoinBase()) {
        BOOST_FOREACH(const CTxIn &txin, vin) {
            CCoins coins;
            if (!inputs.GetCoins(txin.prevout.hash, coins))
                return error("UpdateCoins() : cannot find prevtx");
            if (coins.nTime > nTimeStamp)
                return error("UpdateCoins() : timestamp violation");
            CTxInUndo undo;
            if (!coins.Spend(txin.prevout, undo))
                return error("UpdateCoins() : cannot spend input");
            txundo.vprevout.push_back(undo);
            if (!inputs.SetCoins(txin.prevout.hash, coins))
                return error("UpdateCoins() : cannot update input");
        }
    }

    // add outputs
    if (!inputs.SetCoins(hash, CCoins(*this, nHeight, nTimeStamp)))
        return error("UpdateCoins() : cannot update output");

    return true;
}

bool CTransaction::HaveInputs(CCoinsView &inputs) const
{
    if (!IsCoinBase()) {
        // first check whether information about the prevout hash is available
        for (unsigned int i = 0; i < vin.size(); i++) {
            const COutPoint &prevout = vin[i].prevout;
            if (!inputs.HaveCoins(prevout.hash))
                return false;
        }

        // then check whether the actual outputs are available
        for (unsigned int i = 0; i < vin.size(); i++) {
            const COutPoint &prevout = vin[i].prevout;
            CCoins coins;
            inputs.GetCoins(prevout.hash, coins);
            if (!coins.IsAvailable(prevout.n))
                return false;
        }
    }
    return true;
}

bool CTransaction::CheckInputs(CCoinsView &inputs, enum CheckSig_mode csmode, bool fStrictPayToScriptHash, bool fStrictEncodings, CBlock *pblock) const
{
    if (!IsCoinBase())
    {
        int64 nValueIn = 0;
        int64 nFees = 0;
        for (unsigned int i = 0; i < vin.size(); i++)
        {
            const COutPoint &prevout = vin[i].prevout;
            CCoins coins;
            if (!inputs.GetCoins(prevout.hash, coins))
                return error("CheckInputs() : cannot find prevout tx");

            // 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 (!coins.IsAvailable(prevout.n))
                return error("CheckInputs() : %s prev tx already used", GetHash().ToString().substr(0,10).c_str());

            // If prev is coinbase or coinstake, check that it's matured
            if (coins.IsCoinBase() || coins.IsCoinStake()) {
                CBlockIndex *pindexBlock = inputs.GetBestBlock();
                if (pindexBlock->nHeight - coins.nHeight < nCoinbaseMaturity)
                    return error("CheckInputs() : tried to spend %s at depth %d", coins.IsCoinBase() ? "coinbase" : "coinstake", pindexBlock->nHeight - coins.nHeight);
            }

            // Check transaction timestamp
            if (coins.nTime > nTime)
                return DoS(100, error("CheckInputs() : transaction timestamp earlier than input transaction"));

            // Check for negative or overflow input values
            nValueIn += coins.vout[prevout.n].nValue;
            if (!MoneyRange(coins.vout[prevout.n].nValue) || !MoneyRange(nValueIn))
                return DoS(100, error("CheckInputs() : txin values out of range"));
        }

        if (IsCoinStake())
        {
            if (!pblock)
                return error("CheckInputs() : %s is a coinstake, but no block specified", GetHash().ToString().substr(0,10).c_str());

            // Coin stake tx earns reward instead of paying fee
            uint64 nCoinAge;
            if (!GetCoinAge(nCoinAge))
                return error("CheckInputs() : %s unable to get coin age for coinstake", GetHash().ToString().substr(0,10).c_str());

            int64 nStakeReward = GetValueOut() - nValueIn;
            int64 nCalculatedStakeReward = GetProofOfStakeReward(nCoinAge, pblock->nBits, nTime) - GetMinFee() + MIN_TX_FEE;

            if (nStakeReward > nCalculatedStakeReward)
                return DoS(100, error("CheckInputs() : coinstake pays too much(actual=%"PRI64d" vs calculated=%"PRI64d")", nStakeReward, nCalculatedStakeReward));
        }
        else
        {
            if (nValueIn < GetValueOut())
                return DoS(100, error("ChecktInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));

            // Tally transaction fees
            int64 nTxFee = nValueIn - GetValueOut();
            if (nTxFee < 0)
                return DoS(100, error("CheckInputs() : %s nTxFee < 0", GetHash().ToString().substr(0,10).c_str()));
            nFees += nTxFee;
            if (!MoneyRange(nFees))
                return DoS(100, error("CheckInputs() : nFees out of range"));

            // enforce transaction fees for every block until 1 May 2014 04:00:00 GMT
            if (!fTestNet && nTxFee < GetMinFee() && nTime < OUTPUT_SWITCH_TIME)
                return pblock? DoS(100, error("CheckInputs() : %s not paying required fee=%s, paid=%s", GetHash().ToString().substr(0,10).c_str(), FormatMoney(GetMinFee()).c_str(), FormatMoney(nTxFee).c_str())) : false;
        }

        // The first loop above does all the inexpensive checks.
        // Only if ALL inputs pass do we perform expensive ECDSA signature checks.
        // Helps prevent CPU exhaustion attacks.

        // Skip ECDSA signature verification when connecting blocks
        // before the last 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 (csmode == CS_ALWAYS || 
            (csmode == CS_AFTER_CHECKPOINT && inputs.GetBestBlock()->nHeight >= Checkpoints::GetTotalBlocksEstimate())) {
            for (unsigned int i = 0; i < vin.size(); i++) {
                const COutPoint &prevout = vin[i].prevout;
                CCoins coins;
                inputs.GetCoins(prevout.hash, coins);

                // Verify signature
                if (!VerifySignature(coins, *this, i, fStrictPayToScriptHash, fStrictEncodings, 0)) {
                    // only during transition phase for P2SH: do not invoke anti-DoS code for
                    // potentially old clients relaying bad P2SH transactions
                    if (fStrictPayToScriptHash && VerifySignature(coins, *this, i, false, fStrictEncodings, 0))
                        return error("CheckInputs() : %s P2SH VerifySignature failed", GetHash().ToString().substr(0,10).c_str());

                    return DoS(100,error("CheckInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
                }
            }
        }
    }

    return true;
}


bool CTransaction::ClientCheckInputs() const
{
    if (IsCoinBase())
        return false;

    // Take over previous transactions' spent pointers
    {
        LOCK(mempool.cs);
        int64 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(CCoins(txPrev, -1, -1), *this, i, true, false, 0))
                return error("ConnectInputs() : VerifySignature failed");

            ///// this is redundant with the mempool.mapNextTx stuff,
            ///// not sure which I want to get rid of
            ///// this has to go away now that posNext is gone
            // // Check for conflicts
            // if (!txPrev.vout[prevout.n].posNext.IsNull())
            //     return error("ConnectInputs() : prev tx already used");
            //
            // // Flag outpoints as used
            // txPrev.vout[prevout.n].posNext = posThisTx;

            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(CBlockIndex *pindex, CCoinsView &view)
{
    assert(pindex == view.GetBestBlock());

    CBlockUndo blockUndo;
    {
        CDiskBlockPos pos = pindex->GetUndoPos();
        if (pos.IsNull())
            return error("DisconnectBlock() : no undo data available");
        FILE *file = OpenUndoFile(pos, true);
        if (file == NULL)
            return error("DisconnectBlock() : undo file not available");
        CAutoFile fileUndo(file, SER_DISK, CLIENT_VERSION);
        fileUndo >> blockUndo;
    }

    assert(blockUndo.vtxundo.size() + 1 == vtx.size());

    // undo transactions in reverse order
    for (int i = vtx.size() - 1; i >= 0; i--) {
        const CTransaction &tx = vtx[i];
        uint256 hash = tx.GetHash();

        // check that all outputs are available
        CCoins outs;
        if (!view.GetCoins(hash, outs))
            return error("DisconnectBlock() : outputs still spent? database corrupted");

        CCoins outsBlock = CCoins(tx, pindex->nHeight, pindex->nTime);
        if (outs != outsBlock)
            return error("DisconnectBlock() : added transaction mismatch? database corrupted");

        // remove outputs
        if (!view.SetCoins(hash, CCoins()))
            return error("DisconnectBlock() : cannot delete coin outputs");

        // restore inputs
        if (i > 0) { // not coinbases
            const CTxUndo &txundo = blockUndo.vtxundo[i-1];
            assert(txundo.vprevout.size() == tx.vin.size());
            for (unsigned int j = tx.vin.size(); j-- > 0;) {
                const COutPoint &out = tx.vin[j].prevout;
                const CTxInUndo &undo = txundo.vprevout[j];
                CCoins coins;
                view.GetCoins(out.hash, coins); // this can fail if the prevout was already entirely spent
                if (coins.IsPruned()) {
                    if (undo.nHeight == 0)
                        return error("DisconnectBlock() : undo data doesn't contain tx metadata? database corrupted");
                    coins.fCoinBase = undo.fCoinBase;
                    coins.fCoinStake = undo.fCoinStake;
                    coins.nHeight = undo.nHeight;
                    coins.nTime = undo.nTime;
                    coins.nBlockTime = undo.nBlockTime;
                    coins.nVersion = undo.nVersion;
                } else {
                    if (undo.nHeight != 0)
                        return error("DisconnectBlock() : undo data contains unneeded tx metadata? database corrupted");
                }
                if (coins.IsAvailable(out.n))
                    return error("DisconnectBlock() : prevout output not spent? database corrupted");
                if (coins.vout.size() < out.n+1)
                    coins.vout.resize(out.n+1);
                coins.vout[out.n] = undo.txout;
                if (!view.SetCoins(out.hash, coins))
                    return error("DisconnectBlock() : cannot restore coin inputs");
            }
        }
    }

    // move best block pointer to prevout block
    view.SetBestBlock(pindex->pprev);

    return true;
}

bool FindUndoPos(CChainDB &chaindb, int nFile, CDiskBlockPos &pos, unsigned int nAddSize);

bool CBlock::ConnectBlock(CBlockIndex* pindex, CCoinsView &view, bool fJustCheck)
{
    // Check it again in case a previous version let a bad block in
    if (!CheckBlock(!fJustCheck, !fJustCheck))
        return false;

    // verify that the view's current state corresponds to the previous block
    assert(pindex->pprev == view.GetBestBlock());

    // 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.
    bool fEnforceBIP30 = true;

    if (fEnforceBIP30) {
        BOOST_FOREACH(CTransaction& tx, vtx) {
            uint256 hash = tx.GetHash();
            CCoins coins;
            if (view.GetCoins(hash, coins) && !coins.IsPruned())
                return error("ConnectBlock() : tried to overwrite transaction");
        }
    }

    // BIP16 always active
    bool fStrictPayToScriptHash = true;

    CBlockUndo blockundo;

    int64 nFees = 0, nValueIn = 0, nValueOut = 0;
    unsigned int nSigOps = 0;
    BOOST_FOREACH(CTransaction& tx, vtx)
    {
        nSigOps += tx.GetLegacySigOpCount();
        if (nSigOps > MAX_BLOCK_SIGOPS)
            return DoS(100, error("ConnectBlock() : too many sigops"));

        if (!tx.IsCoinBase())
        {
            if (!tx.HaveInputs(view))
                return DoS(100, error("ConnectBlock() : inputs missing/spent"));

            if (fStrictPayToScriptHash)
            {
                // 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(view);
                if (nSigOps > MAX_BLOCK_SIGOPS)
                     return DoS(100, error("ConnectBlock() : too many sigops"));
            }

            int64 nTxValueOut = tx.GetValueOut();
            int64 nTxValueIn  = tx.GetValueIn(view);

            nValueIn += nTxValueIn;
            nValueOut += nTxValueOut;

            if (!tx.IsCoinStake())
                nFees += nTxValueIn - nTxValueOut;

            if (!tx.CheckInputs(view, CS_AFTER_CHECKPOINT, fStrictPayToScriptHash, false, this))
                return false;
        }
        else
        {
            nValueOut += tx.GetValueOut();
        }

        CTxUndo txundo;
        if (!tx.UpdateCoins(view, txundo, pindex->nHeight, pindex->nTime))
            return error("ConnectBlock() : UpdateInputs failed");
        if (!tx.IsCoinBase())
            blockundo.vtxundo.push_back(txundo);
    }

    pindex->nMint = nValueOut - nValueIn + nFees;
    pindex->nMoneySupply = (pindex->pprev? pindex->pprev->nMoneySupply : 0) + nValueOut - nValueIn;

    if (fJustCheck)
        return true;

    CChainDB chaindb;
    CDiskBlockPos pos;

    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull())
    {
        if (!FindUndoPos(chaindb, pindex->pos.nFile, pos, ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) + 8))
            return error("ConnectBlock() : FindUndoPos failed");
        if (!blockundo.WriteToDisk(pos))
            return error("ConnectBlock() : CBlockUndo::WriteToDisk failed");

        // update nUndoPos in block index
        pindex->nUndoPos = pos.nPos + 1;
    }

    CDiskBlockIndex blockindex(pindex);
    if (!chaindb.WriteBlockIndex(blockindex))
        return error("ConnectBlock() : WriteBlockIndex failed");

    // add this block to the view's blockchain
    if (!view.SetBestBlock(pindex))
        return false;

    // fees are destroyed to compensate the entire network
    if (fDebug && GetBoolArg("-printcreation"))
        printf("ConnectBlock() : destroy=%s nFees=%"PRI64d"\n", FormatMoney(nFees).c_str(), nFees);

    // Watch for transactions paying to me
    BOOST_FOREACH(CTransaction& tx, vtx)
        SyncWithWallets(tx, this, true);

    return true;
}

bool CBlock::SetBestChain(CBlockIndex* pindexNew)
{
    CCoinsViewCache &view = *pcoinsTip;

    // special case for attaching the genesis block
    // note that no ConnectBlock is called, so its coinbase output is non-spendable
    if (pindexGenesisBlock == NULL && pindexNew->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet))
    {
        view.SetBestBlock(pindexNew);
        if (!view.Flush())
            return false;
        pindexGenesisBlock = pindexNew;
        pindexBest = pindexNew;
        hashBestChain = pindexNew->GetBlockHash();
        nBestHeight = pindexBest->nHeight;
        nBestChainTrust = pindexNew->nChainTrust;
        return true;
    }

    // Find the fork (typically, there is none)
    CBlockIndex* pfork = view.GetBestBlock();
    CBlockIndex* plonger = pindexNew;
    while (pfork != plonger)
    {
        while (plonger->nHeight > pfork->nHeight)
            if (!(plonger = plonger->pprev))
                return error("SetBestChain() : plonger->pprev is null");
        if (pfork == plonger)
            break;
        if (!(pfork = pfork->pprev))
            return error("SetBestChain() : pfork->pprev is null");
    }

    // List of what to disconnect (typically nothing)
    vector<CBlockIndex*> vDisconnect;
    for (CBlockIndex* pindex = view.GetBestBlock(); pindex != pfork; pindex = pindex->pprev)
        vDisconnect.push_back(pindex);

    // List of what to connect (typically only pindexNew)
    vector<CBlockIndex*> vConnect;
    for (CBlockIndex* pindex = pindexNew; pindex != pfork; pindex = pindex->pprev)
        vConnect.push_back(pindex);
    reverse(vConnect.begin(), vConnect.end());

    if (vDisconnect.size() > 0) {
        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("SetBestBlock() : ReadFromDisk for disconnect failed");
        CCoinsViewCache viewTemp(view, true);
        if (!block.DisconnectBlock(pindex, viewTemp))
            return error("SetBestBlock() : DisconnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
        if (!viewTemp.Flush())
            return error("SetBestBlock() : Cache flush failed after disconnect");

        // 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;
    BOOST_FOREACH(CBlockIndex *pindex, vConnect) {
        CBlock block;
        CBlock *pblock;
        if (pindex == pindexNew) // connecting *this block
            pblock = this;
        else { // other block; read it from disk
            if (!block.ReadFromDisk(pindex))
                return error("SetBestBlock() : ReadFromDisk for connect failed");
            pblock = &block;
        }
        CCoinsViewCache viewTemp(view, true);
        if (!pblock->ConnectBlock(pindex, viewTemp)) {
            InvalidChainFound(pindexNew);
            return error("SetBestBlock() : ConnectBlock %s failed", pindex->GetBlockHash().ToString().substr(0,20).c_str());
        }
        if (!viewTemp.Flush())
            return error("SetBestBlock() : Cache flush failed after connect");

        // Queue memory transactions to delete
        BOOST_FOREACH(const CTransaction& tx, pblock->vtx)
            vDelete.push_back(tx);
    }

    // Make sure it's successfully written to disk before changing memory structure
    bool fIsInitialDownload = IsInitialBlockDownload();
    if (!fIsInitialDownload || view.GetCacheSize()>5000)
        if (!view.Flush())
            return false;

    // At this point, all changes have been done to the database.
    // Proceed by updating the memory structures.

    // 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(false);

    // Delete redundant memory transactions that are in the connected branch
    BOOST_FOREACH(CTransaction& tx, vDelete)
        mempool.remove(tx);

    // Update best block in wallet (so we can detect restored wallets)
    if (!fIsInitialDownload)
    {
        const CBlockLocator locator(pindexNew);
        ::SetBestChain(locator);
    }

    // New best block
    hashBestChain = pindexNew->GetBlockHash();
    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=%"PRI64d"  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;
}

// 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(uint64& nCoinAge) const
{
    CCoinsViewCache &inputs = *pcoinsTip;

    CBigNum bnCentSecond = 0;  // coin age in the unit of cent-seconds
    nCoinAge = 0;

    if (IsCoinBase())
        return true;

    for (unsigned int i = 0; i < vin.size(); i++)
    {
        const COutPoint &prevout = vin[i].prevout;
        CCoins coins;
        if (!inputs.GetCoins(prevout.hash, coins))
            continue;

        if (nTime < coins.nTime)
            return false;  // Transaction timestamp violation

        // only count coins meeting min age requirement
        if (coins.nBlockTime + nStakeMinAge > nTime)
            continue;

        int64 nValueIn = coins.vout[vin[i].prevout.n].nValue;
        bnCentSecond += CBigNum(nValueIn) * (nTime-coins.nTime) / CENT;
    }

    CBigNum bnCoinDay = bnCentSecond * CENT / COIN / (24 * 60 * 60);
    if (fDebug && GetBoolArg("-printcoinage"))
        printf("coin age bnCoinDay=%s\n", bnCoinDay.ToString().c_str());
    nCoinAge = bnCoinDay.getuint64();
    return true;
}

// Total coin age spent in block, in the unit of coin-days.
bool CBlock::GetCoinAge(uint64& nCoinAge) const
{
    nCoinAge = 0;

    BOOST_FOREACH(const CTransaction& tx, vtx)
    {
        uint64 nTxCoinAge;
        if (tx.GetCoinAge(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=%"PRI64d"\n", nCoinAge);
    return true;
}

bool CBlock::AddToBlockIndex(const CDiskBlockPos &pos)
{
    // 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(*this);
    if (!pindexNew)
        return error("AddToBlockIndex() : new CBlockIndex failed");
    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
    pindexNew->phashBlock = &((*mi).first);
    map<uint256, CBlockIndex*>::iterator miPrev = mapBlockIndex.find(hashPrevBlock);
    if (miPrev != mapBlockIndex.end())
    {
        pindexNew->pprev = (*miPrev).second;
        pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
    }
    pindexNew->nChainTrust = (pindexNew->pprev ? pindexNew->pprev->nChainTrust : 0) + pindexNew->GetBlockTrust();
    pindexNew->pos = pos;
    pindexNew->nUndoPos = 0;

    // Compute stake entropy bit for stake modifier
    if (!pindexNew->SetStakeEntropyBit(GetStakeEntropyBit(pindexNew->nTime)))
        return error("AddToBlockIndex() : SetStakeEntropyBit() failed");

    // Record proof-of-stake hash value
    if (pindexNew->IsProofOfStake())
    {
        if (!mapProofOfStake.count(hash))
            return error("AddToBlockIndex() : hashProofOfStake not found in map");
        pindexNew->hashProofOfStake = mapProofOfStake[hash];
    }

    // Compute stake modifier
    uint64 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"PRI64x, pindexNew->nHeight, nStakeModifier);

    CChainDB chaindb;
    if (!chaindb.TxnBegin())
        return false;
    chaindb.WriteBlockIndex(CDiskBlockIndex(pindexNew));
    if (!chaindb.TxnCommit())
        return false;

    // New best
    if (!SetBestChain(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 FindBlockPos(CChainDB &chaindb, CDiskBlockPos &pos, unsigned int nAddSize, unsigned int nHeight, uint64 nTime)
{
    bool fUpdatedLast = false;

    LOCK(cs_LastBlockFile);

    while (infoLastBlockFile.nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
        printf("Leaving block file %i: %s\n", nLastBlockFile, infoLastBlockFile.ToString().c_str());
        FILE *file = OpenBlockFile(pos);
        FileCommit(file);
        fclose(file);
        file = OpenUndoFile(pos);
        FileCommit(file);
        fclose(file);
        nLastBlockFile++;
        infoLastBlockFile.SetNull();
        chaindb.ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile); // check whether data for the new file somehow already exist; can fail just fine
        fUpdatedLast = true;
    }

    pos.nFile = nLastBlockFile;
    pos.nPos = infoLastBlockFile.nSize;
    infoLastBlockFile.nSize += nAddSize;
    infoLastBlockFile.AddBlock(nHeight, nTime);

    unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
    unsigned int nNewChunks = (infoLastBlockFile.nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
    if (nNewChunks > nOldChunks) {
        FILE *file = OpenBlockFile(pos);
        if (file) {
            printf("Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
            AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
        }
        fclose(file);
    }

    if (!chaindb.WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
        return error("FindBlockPos() : cannot write updated block info");
    if (fUpdatedLast)
        chaindb.WriteLastBlockFile(nLastBlockFile);

    return true;
}

bool FindUndoPos(CChainDB &chaindb, int nFile, CDiskBlockPos &pos, unsigned int nAddSize)
{
    pos.nFile = nFile;

    LOCK(cs_LastBlockFile);

    unsigned int nNewSize;
    if (nFile == nLastBlockFile) {
        pos.nPos = infoLastBlockFile.nUndoSize;
        nNewSize = (infoLastBlockFile.nUndoSize += nAddSize);
        if (!chaindb.WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
            return error("FindUndoPos() : cannot write updated block info");
    } else {
        CBlockFileInfo info;
        if (!chaindb.ReadBlockFileInfo(nFile, info))
            return error("FindUndoPos() : cannot read block info");
        pos.nPos = info.nUndoSize;
        nNewSize = (info.nUndoSize += nAddSize);
        if (!chaindb.WriteBlockFileInfo(nFile, info))
            return error("FindUndoPos() : cannot write updated block info");
    }

    unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    if (nNewChunks > nOldChunks) {
        FILE *file = OpenUndoFile(pos);
        if (file) {
            printf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
            AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
        }
        fclose(file);
    }

    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() > GetAdjustedTime() + 2 * 60 * 60)
        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)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)vtx[1].nTime))
            return DoS(50, error("CheckBlock() : coinstake timestamp violation nTimeBlock=%"PRI64d" nTimeTx=%u", GetBlockTime(), vtx[1].nTime));

        // NovaCoin: check proof-of-stake block signature
        if (fCheckSig && !CheckBlockSignature(true))
            return DoS(100, error("CheckBlock() : bad proof-of-stake block signature"));
    }
    else
    {
        int64 nReward = GetProofOfWorkReward(nBits);
        // Check coinbase reward
        if (vtx[0].GetValueOut() > nReward)
            return DoS(50, error("CheckBlock() : coinbase reward exceeded (actual=%"PRI64d" vs calculated=%"PRI64d")",
                   vtx[0].GetValueOut(),
                   nReward));

        // Should we check proof-of-work block signature or not?
        //
        // * Always skip on TestNet
        // * Perform checking for the first 9689 blocks
        // * Perform checking since last checkpoint until 20 Sep 2013 (will be removed after)

        if(!fTestNet && fCheckSig)
        {
            bool checkEntropySig = (GetBlockTime() < ENTROPY_SWITCH_TIME);

            // NovaCoin: check proof-of-work block signature
            if (checkEntropySig && !CheckBlockSignature(false))
                return DoS(100, error("CheckBlock() : bad proof-of-work block signature"));
        }
    }


    // Check transactions
    BOOST_FOREACH(const CTransaction& tx, vtx)
    {
        if (!tx.CheckTransaction())
            return DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));

        // check transaction timestamp
        if (GetBlockTime() < (int64)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;

    // 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->GetMedianTimePast() || 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));

    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!");

    // Enforce rule that the coinbase starts with serialized block height
    CScript expect = CScript() << nHeight;
    if (vtx[0].vin[0].scriptSig.size() < expect.size() ||
        !std::equal(expect.begin(), expect.end(), vtx[0].vin[0].scriptSig.begin()))
        return DoS(100, error("AcceptBlock() : block height mismatch in coinbase"));

    // Write block to history file
    unsigned int nBlockSize = ::GetSerializeSize(*this, SER_DISK, CLIENT_VERSION);
    if (!CheckDiskSpace(::GetSerializeSize(*this, SER_DISK, CLIENT_VERSION)))
        return error("AcceptBlock() : out of disk space");
    CDiskBlockPos blockPos;
    {
        CChainDB chaindb;
        if (!FindBlockPos(chaindb, blockPos, nBlockSize+8, nHeight, nTime))
            return error("AcceptBlock() : FindBlockPos failed");
    }
    if (!WriteToDisk(blockPos))
        return error("AcceptBlock() : WriteToDisk failed");
    if (!AddToBlockIndex(blockPos))
        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));
    }

    // Check pending sync-checkpoint
    Checkpoints::AcceptPendingSyncCheckpoint();

    return true;
}

uint256 CBlockIndex::GetBlockTrust() const
{
    CBigNum bnTarget;
    bnTarget.SetCompact(nBits);

    if (bnTarget <= 0)
        return 0;

    /* Old protocol */
    if (!fTestNet && GetBlockTime() < CHAINCHECKS_SWITCH_TIME)
        return (IsProofOfStake()? ((CBigNum(1)<<256) / (bnTarget+1)).getuint256() : 1);

    /* New protocol */

    // Calculate work amount for block
    uint256 nPoWTrust = (CBigNum(nPoWBase) / (bnTarget+1)).getuint256();

    // Set nPowTrust to 1 if we are checking PoS block or PoW difficulty is too low
    nPoWTrust = (IsProofOfStake() || nPoWTrust < 1) ? 1 : nPoWTrust;

    // Return nPoWTrust for the first 12 blocks
    if (pprev == NULL || pprev->nHeight < 12)
        return nPoWTrust;

    const CBlockIndex* currentIndex = pprev;

    if(IsProofOfStake())
    {
        CBigNum bnNewTrust = (CBigNum(1)<<256) / (bnTarget+1);

        // Return 1/3 of score if parent block is not the PoW block
        if (!pprev->IsProofOfWork())
            return (bnNewTrust / 3).getuint256();

        int nPoWCount = 0;

        // Check last 12 blocks type
        while (pprev->nHeight - currentIndex->nHeight < 12)
        {
            if (currentIndex->IsProofOfWork())
                nPoWCount++;
            currentIndex = currentIndex->pprev;
        }

        // Return 1/3 of score if less than 3 PoW blocks found
        if (nPoWCount < 3)
            return (bnNewTrust / 3).getuint256();

        return bnNewTrust.getuint256();
    }
    else
    {
        CBigNum bnLastBlockTrust = CBigNum(pprev->nChainTrust - pprev->pprev->nChainTrust);

        // Return nPoWTrust + 2/3 of previous block score if two parent blocks are not PoS blocks
        if (!(pprev->IsProofOfStake() && pprev->pprev->IsProofOfStake()))
            return nPoWTrust + (2 * bnLastBlockTrust / 3).getuint256();

        int nPoSCount = 0;

        // Check last 12 blocks type
        while (pprev->nHeight - currentIndex->nHeight < 12)
        {
            if (currentIndex->IsProofOfStake())
                nPoSCount++;
            currentIndex = currentIndex->pprev;
        }

        // Return nPoWTrust + 2/3 of previous block score if less than 7 PoS blocks found
        if (nPoSCount < 7)
            return nPoWTrust + (2 * bnLastBlockTrust / 3).getuint256();

        bnTarget.SetCompact(pprev->nBits);

        if (bnTarget <= 0)
            return 0;

        CBigNum bnNewTrust = (CBigNum(1)<<256) / (bnTarget+1);

        // Return nPoWTrust + full trust score for previous block nBits
        return nPoWTrust + bnNewTrust.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");

    // ppcoin: verify hash target and signature of coinstake tx
    if (pblock->IsProofOfStake())
    {
        uint256 hashProofOfStake = 0, targetProofOfStake = 0;
        if (!CheckProofOfStake(pblock->vtx[1], pblock->nBits, hashProofOfStake, targetProofOfStake))
        {
            printf("WARNING: ProcessBlock(): 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
        }
        if (!mapProofOfStake.count(hash)) // add to mapProofOfStake
            mapProofOfStake.insert(make_pair(hash, hashProofOfStake));
    }

    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 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;
}

// novacoin: attempt to generate suitable proof-of-stake
bool CBlock::SignBlock(CWallet& wallet)
{
    // 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 nLastCoinStakeSearchTime = GetAdjustedTime(); // startup timestamp

    CKey key;
    CTransaction txCoinStake;
    int64 nSearchTime = txCoinStake.nTime; // search to current time

    if (nSearchTime > nLastCoinStakeSearchTime)
    {
        if (wallet.CreateCoinStake(wallet, nBits, nSearchTime-nLastCoinStakeSearchTime, txCoinStake, key))
        {
            if (txCoinStake.nTime >= max(pindexBest->GetMedianTimePast()+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->GetMedianTimePast()+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;
}

// ppcoin: check block signature
bool CBlock::CheckBlockSignature(bool fProofOfStake) const
{
    if (GetHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet))
        return vchBlockSig.empty();

    vector<valtype> vSolutions;
    txnouttype whichType;

    if(fProofOfStake)
    {
        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);
        }
    }
    else
    {
        for(unsigned int i = 0; i < vtx[0].vout.size(); i++)
        {
            const CTxOut& txout = vtx[0].vout[i];

            if (!Solver(txout.scriptPubKey, whichType, vSolutions))
                return false;

            if (whichType == TX_PUBKEY)
            {
                // Verify
                valtype& vchPubKey = vSolutions[0];
                CKey key;
                if (!key.SetPubKey(vchPubKey))
                    continue;
                if (vchBlockSig.empty())
                    continue;
                if(!key.Verify(GetHash(), vchBlockSig))
                    continue;

                return true;
            }
        }
    }
    return false;
}

bool CheckDiskSpace(uint64 nAdditionalBytes)
{
    uint64 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, "NovaCoin", CClientUIInterface::OK | CClientUIInterface::ICON_EXCLAMATION | CClientUIInterface::MODAL);
        StartShutdown();
        return false;
    }
    return true;
}


CCriticalSection cs_LastBlockFile;
CBlockFileInfo infoLastBlockFile;
int nLastBlockFile = 0;

FILE* OpenDiskFile(const CDiskBlockPos &pos, const char *prefix, bool fReadOnly)
{
    if (pos.IsNull())
        return NULL;
    boost::filesystem::path path = GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
    boost::filesystem::create_directories(path.parent_path());
    FILE* file = fopen(path.string().c_str(), "rb+");
    if (!file && !fReadOnly)
        file = fopen(path.string().c_str(), "wb+");
    if (!file) {
        printf("Unable to open file %s\n", path.string().c_str());
        return NULL;
    }
    if (pos.nPos) {
        if (fseek(file, pos.nPos, SEEK_SET)) {
            printf("Unable to seek to position %u of %s\n", pos.nPos, path.string().c_str());
            fclose(file);
            return NULL;
        }
    }
    return file;
}

FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
    return OpenDiskFile(pos, "blk", fReadOnly);
}

FILE *OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
    return OpenDiskFile(pos, "rev", fReadOnly);
}

bool LoadBlockIndex(bool fAllowNew)
{
    CBigNum bnTrustedModulus;

    if (fTestNet)
    {
        pchMessageStart[0] = 0xcd;
        pchMessageStart[1] = 0xf2;
        pchMessageStart[2] = 0xc0;
        pchMessageStart[3] = 0xef;

        bnTrustedModulus.SetHex("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");
        bnProofOfWorkLimit = bnProofOfWorkLimitTestNet; // 16 bits PoW target limit for testnet
        nStakeMinAge = 2 * 60 * 60; // test net min age is 2 hours
        nModifierInterval = 20 * 60; // test modifier interval is 20 minutes
        nCoinbaseMaturity = 10; // test maturity is 10 blocks
        nStakeTargetSpacing = 5 * 60; // test block spacing is 5 minutes
    }
    else
    {
        bnTrustedModulus.SetHex("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");
    }

    // Set up the Zerocoin Params object
    ZCParams = new libzerocoin::Params(bnTrustedModulus);

    //
    // Load block index
    //
    CChainDB chaindb("cr");
    if (!LoadBlockIndex(chaindb))
        return false;
    chaindb.Close();

    //
    // Init with genesis block
    //
    if (mapBlockIndex.empty())
    {
        if (!fAllowNew)
            return false;

        // Genesis block

        // MainNet:

        //CBlock(hash=00000a060336cbb72fe969666d337b87198b1add2abaa59cca226820b32933a4, ver=1, hashPrevBlock=0000000000000000000000000000000000000000000000000000000000000000, hashMerkleRoot=4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b, nTime=1360105017, nBits=1e0fffff, nNonce=1575379, vtx=1, vchBlockSig=)
        //  Coinbase(hash=4cb33b3b6a, nTime=1360105017, ver=1, vin.size=1, vout.size=1, nLockTime=0)
        //    CTxIn(COutPoint(0000000000, 4294967295), coinbase 04ffff001d020f274468747470733a2f2f626974636f696e74616c6b2e6f72672f696e6465782e7068703f746f7069633d3133343137392e6d736731353032313936236d736731353032313936)
        //    CTxOut(empty)
        //  vMerkleTree: 4cb33b3b6a

        // TestNet:

        //CBlock(hash=0000c763e402f2436da9ed36c7286f62c3f6e5dbafce9ff289bd43d7459327eb, ver=1, hashPrevBlock=0000000000000000000000000000000000000000000000000000000000000000, hashMerkleRoot=4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b, nTime=1360105017, nBits=1f00ffff, nNonce=46534, vtx=1, vchBlockSig=)
        //  Coinbase(hash=4cb33b3b6a, nTime=1360105017, ver=1, vin.size=1, vout.size=1, nLockTime=0)
        //    CTxIn(COutPoint(0000000000, 4294967295), coinbase 04ffff001d020f274468747470733a2f2f626974636f696e74616c6b2e6f72672f696e6465782e7068703f746f7069633d3133343137392e6d736731353032313936236d736731353032313936)
        //    CTxOut(empty)
        //  vMerkleTree: 4cb33b3b6a

        const char* pszTimestamp = "https://bitcointalk.org/index.php?topic=134179.msg1502196#msg1502196";
        CTransaction txNew;
        txNew.nTime = 1360105017;
        txNew.vin.resize(1);
        txNew.vout.resize(1);
        txNew.vin[0].scriptSig = CScript() << 486604799 << CBigNum(9999) << 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    = 1360105017;
        block.nBits    = bnProofOfWorkLimit.GetCompact();
        block.nNonce   = !fTestNet ? 1575379 : 46534;

        //// debug print
        uint256 hash = block.GetHash();
        printf("%s\n", hash.ToString().c_str());
        assert(block.hashMerkleRoot == uint256("0x4cb33b3b6a861dcbc685d3e614a9cafb945738d6833f182855679f2fad02057b"));
        block.print();
        assert(hash == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet));
        assert(block.CheckBlock());

        // Start new block file
        unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
        CDiskBlockPos blockPos;
        {
            CChainDB chaindb;
            if (!FindBlockPos(chaindb, blockPos, nBlockSize+8, 0, block.nTime))
                return error("AcceptBlock() : FindBlockPos failed");
        }
        if (!block.WriteToDisk(blockPos))
            return error("LoadBlockIndex() : writing genesis block to disk failed");
        if (!block.AddToBlockIndex(blockPos))
            return error("LoadBlockIndex() : genesis block not accepted");

        // initialize synchronized checkpoint
        if (!Checkpoints::WriteSyncCheckpoint((!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet)))
            return error("LoadBlockIndex() : failed to init sync checkpoint");
    }

    string strPubKey = "";
    {
        CChainDB chaindb;
        // if checkpoint master key changed must reset sync-checkpoint
        if (!chaindb.ReadCheckpointPubKey(strPubKey) || strPubKey != CSyncCheckpoint::strMasterPubKey)
        {
            // write checkpoint master key to db
            chaindb.TxnBegin();
            if (!chaindb.WriteCheckpointPubKey(CSyncCheckpoint::strMasterPubKey))
                return error("LoadBlockIndex() : failed to write new checkpoint master key to db");
            if (!chaindb.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 (blk%05u.dat:0x%x)  %s  tx %"PRIszu"",
            pindex->nHeight,
            pindex->GetBlockPos().nFile, pindex->GetBlockPos().nPos,
            DateTimeStrFormat("%x %H:%M:%S", block.GetBlockTime()).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 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 %"PRI64d"ms\n", nLoaded, GetTimeMillis() - nStart);
    return nLoaded > 0;
}

//////////////////////////////////////////////////////////////////////////////
//
// CAlert
//

extern map<uint256, CAlert> mapAlerts;
extern CCriticalSection cs_mapAlerts;

extern string strMintMessage;
extern string strMintWarning;

string GetWarnings(string strFor)
{
    int nPriority = 0;
    string strStatusBar;
    string strRPC;

    if (GetBoolArg("-testsafemode"))
        strRPC = "test";

    // ppcoin: wallet lock warning for minting
    if (strMintWarning != "")
    {
        nPriority = 0;
        strStatusBar = strMintWarning;
    }

    // Misc warnings like out of disk space and clock is wrong
    if (strMiscWarning != "")
    {
        nPriority = 1000;
        strStatusBar = strMiscWarning;
    }

    // * Should not enter safe mode for longer invalid chain
    // * If sync-checkpoint is too old do not enter safe mode
    // * Display warning only in the STRICT mode
    if (CheckpointsMode == Checkpoints::STRICT && Checkpoints::IsSyncCheckpointTooOld(60 * 60 * 24 * 10) &&
        !fTestNet && !IsInitialBlockDownload())
    {
        nPriority = 100;
        strStatusBar = _("WARNING: Checkpoint is too old. Wait for block chain to download, or notify developers.");
    }

    // ppcoin: 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(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) ||
                pcoinsTip->HaveCoins(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] = { 0xe4, 0xe8, 0xe9, 0xe5 };

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 nTime;
        CAddress addrMe;
        CAddress addrFrom;
        uint64 nNonce = 1;
        vRecv >> pfrom->nVersion >> pfrom->nServices >> nTime >> addrMe;
        if (pfrom->nVersion < MIN_PROTO_VERSION)
        {
            // Since February 20, 2012, the protocol is initiated at version 209,
            // and earlier versions are no longer supported
            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);

        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 nNow = GetAdjustedTime();
        int64 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 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;
            }
        }
        for (unsigned int nInv = 0; nInv < vInv.size(); nInv++)
        {
            const CInv &inv = vInv[nInv];

            if (fShutdown)
                return true;
            pfrom->AddInventoryKnown(inv);

            bool fAlreadyHave = AlreadyHave(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() + nStakeMinAge > 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);
        CTransaction tx;
        vRecv >> tx;

        CInv inv(MSG_TX, tx.GetHash());
        pfrom->AddInventoryKnown(inv);

        bool fMissingInputs = false;
        if (tx.AcceptToMemoryPool(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(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 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 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 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 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 nNow = GetTime() * 1000000;
        while (!pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
        {
            const CInv& inv = (*pto->mapAskFor.begin()).second;
            if (!AlreadyHave(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;
}

// Amount compression:
// * If the amount is 0, output 0
// * first, divide the amount (in base units) by the largest power of 10 possible; call the exponent e (e is max 9)
// * if e<9, the last digit of the resulting number cannot be 0; store it as d, and drop it (divide by 10)
//   * call the result n
//   * output 1 + 10*(9*n + d - 1) + e
// * if e==9, we only know the resulting number is not zero, so output 1 + 10*(n - 1) + 9
// (this is decodable, as d is in [1-9] and e is in [0-9])

uint64 CTxOutCompressor::CompressAmount(uint64 n)
{
    if (n == 0)
        return 0;
    int e = 0;
    while (((n % 10) == 0) && e < 9) {
        n /= 10;
        e++;
    }
    if (e < 9) {
        int d = (n % 10);
        assert(d >= 1 && d <= 9);
        n /= 10;
        return 1 + (n*9 + d - 1)*10 + e;
    } else {
        return 1 + (n - 1)*10 + 9;
    }
}

uint64 CTxOutCompressor::DecompressAmount(uint64 x)
{
    // x = 0  OR  x = 1+10*(9*n + d - 1) + e  OR  x = 1+10*(n - 1) + 9
    if (x == 0)
        return 0;
    x--;
    // x = 10*(9*n + d - 1) + e
    int e = x % 10;
    x /= 10;
    uint64 n = 0;
    if (e < 9) {
        // x = 9*n + d - 1
        int d = (x % 9) + 1;
        x /= 9;
        // x = n
        n = x*10 + d;
    } else {
        n = x+1;
    }
    while (e) {
        n *= 10;
        e--;
    }
    return n;
}