Tx BlockDataViewer::getPrevTx(TxIn & txin) const
{
   if (txin.isCoinbase())
      return Tx();

   OutPoint op = txin.getOutPoint();
   return getTxByHash(op.getTxHash());
}
TxOut BlockDataViewer::getPrevTxOut(TxIn & txin) const
{
   if (txin.isCoinbase())
      return TxOut();

   OutPoint op = txin.getOutPoint();
   Tx theTx = getTxByHash(op.getTxHash());
   if (!theTx.isInitialized())
      throw runtime_error("couldn't find prev tx");

   uint32_t idx = op.getTxOutIndex();
   return theTx.getTxOutCopy(idx);
}
map<BinaryData, map<BinaryData, TxIOPair> >
ZeroConfContainer::ZCisMineBulkFilter(const Tx & tx,
   const BinaryData & ZCkey, uint32_t txtime, 
   function<bool(const BinaryData&)> filter, 
   bool withSecondOrderMultisig)
{
   // Since 99.999%+ of all transactions are not ours, let's do the 
   // fastest bulk filter possible, even though it will add 
   // redundant computation to the tx that are ours.  In fact,
   // we will skip the TxIn/TxOut convenience methods and follow the
   // pointers directly to the data we want

   /***filter is a pointer to a function that takes in a scrAddr (21 bytes,
   including the prefix) and returns a bool. For supernode, it should return
   true all the time.
   ***/

   map<BinaryData, map<BinaryData, TxIOPair> > processedTxIO;

   BinaryData txHash = tx.getThisHash();
   TxRef txref = db_->getTxRef(txHash);

   if (txref.isInitialized())
   {
      //Found this tx in the db. It is already part of a block thus 
      //is invalid as a ZC
      return processedTxIO;
   }

   uint8_t const * txStartPtr = tx.getPtr();
   for (uint32_t iin = 0; iin<tx.getNumTxIn(); iin++)
   {
      // We have the txin, now check if it contains one of our TxOuts
      OutPoint op;
      op.unserialize(txStartPtr + tx.getTxInOffset(iin), 36);

      //check ZC txhash first, always cheaper than grabing a stxo from DB,
      //and will always be checked if the tx doesn't hit in DB outpoints.
      {
         BinaryData opZcKey;
         if (getKeyForTxHash(op.getTxHash(), opZcKey))
         {
            TxRef outPointRef(opZcKey);
            uint16_t outPointId = op.getTxOutIndex();
            TxIOPair txio(outPointRef, outPointId,
               TxRef(ZCkey), iin);

            Tx chainedZC = getTxByHash(op.getTxHash());

            const TxOut& chainedTxOut = chainedZC.getTxOutCopy(outPointId);

            txio.setTxHashOfOutput(op.getTxHash());
            txio.setTxHashOfInput(txHash);

            txio.setValue(chainedTxOut.getValue());
            txio.setTxTime(txtime);

            BinaryData spentSA = chainedTxOut.getScrAddressStr();
            auto& key_txioPair = processedTxIO[spentSA];
            key_txioPair[txio.getDBKeyOfOutput()] = txio;
            
            auto& wltIdVec = keyToSpentScrAddr_[ZCkey];
            wltIdVec.push_back(spentSA);
            
            txOutsSpentByZC_.insert(txio.getDBKeyOfOutput());
            continue;
         }
      }


      //fetch the TxOut from DB
      BinaryData opKey = op.getDBkey(db_);
      if (opKey.getSize() == 8)
      {
         //found outPoint DBKey, grab the StoredTxOut
         StoredTxOut stxOut;
         if (db_->getStoredTxOut(stxOut, opKey))
         {
            BinaryData sa = stxOut.getScrAddress();
            if (filter(sa))
            {
               TxIOPair txio(TxRef(opKey.getSliceRef(0, 6)), op.getTxOutIndex(),
                  TxRef(ZCkey), iin);

               txio.setTxHashOfOutput(op.getTxHash());
               txio.setTxHashOfInput(txHash);
               txio.setValue(stxOut.getValue());
               txio.setTxTime(txtime);

               auto& key_txioPair = processedTxIO[sa];
               key_txioPair[opKey] = txio;

               auto& wltIdVec = keyToSpentScrAddr_[ZCkey];
               wltIdVec.push_back(sa);

               txOutsSpentByZC_.insert(opKey);
            }
         }
      }
   }

   // Simply convert the TxOut scripts to scrAddrs and check if registered
   for (uint32_t iout = 0; iout<tx.getNumTxOut(); iout++)
   {
      TxOut txout = tx.getTxOutCopy(iout);
      BinaryData scrAddr = txout.getScrAddressStr();
      if (filter(scrAddr))
      {
         TxIOPair txio(TxRef(ZCkey), iout);

         txio.setValue(txout.getValue());
         txio.setTxHashOfOutput(txHash);
         txio.setTxTime(txtime);
         txio.setUTXO(true);

         auto& key_txioPair = processedTxIO[scrAddr];

         key_txioPair[txio.getDBKeyOfOutput()] = txio;
         continue;
      }

      // It's still possible this is a multisig addr involving one of our 
      // existing scrAddrs, even if we aren't explicitly looking for this multisig
      if (withSecondOrderMultisig && txout.getScriptType() ==
         TXOUT_SCRIPT_MULTISIG)
      {
         BinaryRefReader brrmsig(scrAddr);
         uint8_t PREFIX = brrmsig.get_uint8_t();
         (void)PREFIX;
         uint8_t M = brrmsig.get_uint8_t();
         (void)M;
         uint8_t N = brrmsig.get_uint8_t();
         for (uint8_t a = 0; a<N; a++)
         if (filter(HASH160PREFIX + brrmsig.get_BinaryDataRef(20)))
         {
            TxIOPair txio(TxRef(ZCkey), iout);

            txio.setTxHashOfOutput(txHash);
            txio.setValue(txout.getValue());
            txio.setTxTime(txtime);
            txio.setUTXO(true);
            txio.setMultisig(true);

            auto& key_txioPair = processedTxIO[scrAddr];

            key_txioPair[txio.getDBKeyOfOutput()] = txio;
         }
      }
   }

   // If we got here, it's either non std or not ours
   return processedTxIO;
}