text: // Copyright (c) 2016-2018 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef KRYPTOFRANC_BLOCKENCODINGS_H
  #define KRYPTOFRANC_BLOCKENCODINGS_H
  
  #include <primitives/block.h>
  
  #include <memory>
  
  class CTxMemPool;
  
  // Dumb helper to handle CTransaction compression at serialize-time
  struct TransactionCompressor {
  private:
      CTransactionRef& tx;
  public:
      explicit TransactionCompressor(CTransactionRef& txIn) : tx(txIn) {}
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(tx); //TODO: Compress tx encoding
      }
  };
  
  class BlockTransactionsRequest {
  public:
      // A BlockTransactionsRequest message
      uint256 blockhash;
      std::vector<uint16_t> indexes;
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(blockhash);
          uint64_t indexes_size = (uint64_t)indexes.size();
          READWRITE(COMPACTSIZE(indexes_size));
          if (ser_action.ForRead()) {
              size_t i = 0;
              while (indexes.size() < indexes_size) {
                  indexes.resize(std::min((uint64_t)(1000 + indexes.size()), indexes_size));
                  for (; i < indexes.size(); i++) {
                      uint64_t index = 0;
                      READWRITE(COMPACTSIZE(index));
                      if (index > std::numeric_limits<uint16_t>::max())
                          throw std::ios_base::failure("index overflowed 16 bits");
                      indexes[i] = index;
                  }
              }
  
              int32_t offset = 0;
              for (size_t j = 0; j < indexes.size(); j++) {
                  if (int32_t(indexes[j]) + offset > std::numeric_limits<uint16_t>::max())
                      throw std::ios_base::failure("indexes overflowed 16 bits");
                  indexes[j] = indexes[j] + offset;
                  offset = int32_t(indexes[j]) + 1;
              }
          } else {
              for (size_t i = 0; i < indexes.size(); i++) {
                  uint64_t index = indexes[i] - (i == 0 ? 0 : (indexes[i - 1] + 1));
                  READWRITE(COMPACTSIZE(index));
              }
          }
      }
  };
  
  class BlockTransactions {
  public:
      // A BlockTransactions message
      uint256 blockhash;
      std::vector<CTransactionRef> txn;
  
      BlockTransactions() {}
      explicit BlockTransactions(const BlockTransactionsRequest& req) :
          blockhash(req.blockhash), txn(req.indexes.size()) {}
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(blockhash);
          uint64_t txn_size = (uint64_t)txn.size();
          READWRITE(COMPACTSIZE(txn_size));
          if (ser_action.ForRead()) {
              size_t i = 0;
              while (txn.size() < txn_size) {
                  txn.resize(std::min((uint64_t)(1000 + txn.size()), txn_size));
                  for (; i < txn.size(); i++)
                      READWRITE(TransactionCompressor(txn[i]));
              }
          } else {
              for (size_t i = 0; i < txn.size(); i++)
                  READWRITE(TransactionCompressor(txn[i]));
          }
      }
  };
  
  // Dumb serialization/storage-helper for CBlockHeaderAndShortTxIDs and PartiallyDownloadedBlock
  struct PrefilledTransaction {
      // Used as an offset since last prefilled tx in CBlockHeaderAndShortTxIDs,
      // as a proper transaction-in-block-index in PartiallyDownloadedBlock
      uint16_t index;
      CTransactionRef tx;
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          uint64_t idx = index;
          READWRITE(COMPACTSIZE(idx));
          if (idx > std::numeric_limits<uint16_t>::max())
              throw std::ios_base::failure("index overflowed 16-bits");
          index = idx;
          READWRITE(TransactionCompressor(tx));
      }
  };
  
  typedef enum ReadStatus_t
  {
      READ_STATUS_OK,
      READ_STATUS_INVALID, // Invalid object, peer is sending bogus crap
      READ_STATUS_FAILED, // Failed to process object
      READ_STATUS_CHECKBLOCK_FAILED, // Used only by FillBlock to indicate a
                                     // failure in CheckBlock.
  } ReadStatus;
  
  class CBlockHeaderAndShortTxIDs {
  private:
      mutable uint64_t shorttxidk0, shorttxidk1;
      uint64_t nonce;
  
      void FillShortTxIDSelector() const;
  
      friend class PartiallyDownloadedBlock;
  
      static const int SHORTTXIDS_LENGTH = 6;
  protected:
      std::vector<uint64_t> shorttxids;
      std::vector<PrefilledTransaction> prefilledtxn;
  
  public:
      CBlockHeader header;
  
      // Dummy for deserialization
      CBlockHeaderAndShortTxIDs() {}
  
      CBlockHeaderAndShortTxIDs(const CBlock& block, bool fUseWTXID);
  
      uint64_t GetShortID(const uint256& txhash) const;
  
      size_t BlockTxCount() const { return shorttxids.size() + prefilledtxn.size(); }
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(header);
          READWRITE(nonce);
  
          uint64_t shorttxids_size = (uint64_t)shorttxids.size();
          READWRITE(COMPACTSIZE(shorttxids_size));
          if (ser_action.ForRead()) {
              size_t i = 0;
              while (shorttxids.size() < shorttxids_size) {
                  shorttxids.resize(std::min((uint64_t)(1000 + shorttxids.size()), shorttxids_size));
                  for (; i < shorttxids.size(); i++) {
                      uint32_t lsb = 0; uint16_t msb = 0;
                      READWRITE(lsb);
                      READWRITE(msb);
                      shorttxids[i] = (uint64_t(msb) << 32) | uint64_t(lsb);
                      static_assert(SHORTTXIDS_LENGTH == 6, "shorttxids serialization assumes 6-byte shorttxids");
                  }
              }
          } else {
              for (size_t i = 0; i < shorttxids.size(); i++) {
                  uint32_t lsb = shorttxids[i] & 0xffffffff;
                  uint16_t msb = (shorttxids[i] >> 32) & 0xffff;
                  READWRITE(lsb);
                  READWRITE(msb);
              }
          }
  
          READWRITE(prefilledtxn);
  
          if (BlockTxCount() > std::numeric_limits<uint16_t>::max())
              throw std::ios_base::failure("indexes overflowed 16 bits");
  
          if (ser_action.ForRead())
              FillShortTxIDSelector();
      }
  };
  
  class PartiallyDownloadedBlock {
  protected:
      std::vector<CTransactionRef> txn_available;
      size_t prefilled_count = 0, mempool_count = 0, extra_count = 0;
      CTxMemPool* pool;
  public:
      CBlockHeader header;
      explicit PartiallyDownloadedBlock(CTxMemPool* poolIn) : pool(poolIn) {}
  
      // extra_txn is a list of extra transactions to look at, in <witness hash, reference> form
      ReadStatus InitData(const CBlockHeaderAndShortTxIDs& cmpctblock, const std::vector<std::pair<uint256, CTransactionRef>>& extra_txn);
      bool IsTxAvailable(size_t index) const;
      ReadStatus FillBlock(CBlock& block, const std::vector<CTransactionRef>& vtx_missing);
  };
  
  #endif // KRYPTOFRANC_BLOCKENCODINGS_H
  