text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2015 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 BITCOIN_PRIMITIVES_TRANSACTION_H
  #define BITCOIN_PRIMITIVES_TRANSACTION_H
  
  #include "amount.h"
  #include "script/script.h"
  #include "serialize.h"
  #include "uint256.h"
  
  /** Transaction types */
  enum {
      TRANSACTION_NORMAL = 0,
      TRANSACTION_PROVIDER_REGISTER = 1,
      TRANSACTION_PROVIDER_UPDATE_SERVICE = 2,
      TRANSACTION_PROVIDER_UPDATE_REGISTRAR = 3,
      TRANSACTION_PROVIDER_UPDATE_REVOKE = 4,
      TRANSACTION_COINBASE = 5,
      TRANSACTION_QUORUM_COMMITMENT = 6,
  };
  
  /** An outpoint - a combination of a transaction hash and an index n into its vout */
  class COutPoint
  {
  public:
      uint256 hash;
      uint32_t n;
  
      COutPoint() { SetNull(); }
      COutPoint(uint256 hashIn, uint32_t nIn) { hash = hashIn; n = nIn; }
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(hash);
          READWRITE(n);
      }
  
      void SetNull() { hash.SetNull(); n = (uint32_t) -1; }
      bool IsNull() const { return (hash.IsNull() && n == (uint32_t) -1); }
  
      friend bool operator<(const COutPoint& a, const COutPoint& b)
      {
          int cmp = a.hash.Compare(b.hash);
          return cmp < 0 || (cmp == 0 && a.n < b.n);
      }
  
      friend bool operator==(const COutPoint& a, const COutPoint& b)
      {
          return (a.hash == b.hash && a.n == b.n);
      }
  
      friend bool operator!=(const COutPoint& a, const COutPoint& b)
      {
          return !(a == b);
      }
  
      std::string ToString() const;
      std::string ToStringShort() const;
  };
  
  /** An input of a transaction.  It contains the location of the previous
   * transaction's output that it claims and a signature that matches the
   * output's public key.
   */
  class CTxIn
  {
  public:
      COutPoint prevout;
      CScript scriptSig;
      uint32_t nSequence;
  
      /* Setting nSequence to this value for every input in a transaction
       * disables nLockTime. */
      static const uint32_t SEQUENCE_FINAL = 0xffffffff;
  
      /* Below flags apply in the context of BIP 68*/
      /* If this flag set, CTxIn::nSequence is NOT interpreted as a
       * relative lock-time. */
      static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
  
      /* If CTxIn::nSequence encodes a relative lock-time and this flag
       * is set, the relative lock-time has units of 512 seconds,
       * otherwise it specifies blocks with a granularity of 1. */
      static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);
  
      /* If CTxIn::nSequence encodes a relative lock-time, this mask is
       * applied to extract that lock-time from the sequence field. */
      static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;
  
      /* In order to use the same number of bits to encode roughly the
       * same wall-clock duration, and because blocks are naturally
       * limited to occur every 600s on average, the minimum granularity
       * for time-based relative lock-time is fixed at 512 seconds.
       * Converting from CTxIn::nSequence to seconds is performed by
       * multiplying by 512 = 2^9, or equivalently shifting up by
       * 9 bits. */
      static const int SEQUENCE_LOCKTIME_GRANULARITY = 9;
  
      CTxIn()
      {
          nSequence = SEQUENCE_FINAL;
      }
  
      explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);
      CTxIn(uint256 hashPrevTx, uint32_t nOut, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(prevout);
          READWRITE(*(CScriptBase*)(&scriptSig));
          READWRITE(nSequence);
      }
  
      friend bool operator==(const CTxIn& a, const CTxIn& b)
      {
          return (a.prevout   == b.prevout &&
                  a.scriptSig == b.scriptSig &&
                  a.nSequence == b.nSequence);
      }
  
      friend bool operator!=(const CTxIn& a, const CTxIn& b)
      {
          return !(a == b);
      }
  
      friend bool operator<(const CTxIn& a, const CTxIn& b)
      {
          return a.prevout<b.prevout;
      }
  
      std::string ToString() const;
  };
  
  /** An output of a transaction.  It contains the public key that the next input
   * must be able to sign with to claim it.
   */
  class CTxOut
  {
  public:
      CAmount nValue;
      CScript scriptPubKey;
      int nRounds;
  
      CTxOut()
      {
          SetNull();
      }
  
      CTxOut(const CAmount& nValueIn, CScript scriptPubKeyIn, int nRoundsIn = -10);
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          READWRITE(nValue);
          READWRITE(*(CScriptBase*)(&scriptPubKey));
      }
  
      void SetNull()
      {
          nValue = -1;
          scriptPubKey.clear();
          nRounds = -10; // an initial value, should be no way to get this by calculations
      }
  
      bool IsNull() const
      {
          return (nValue == -1);
      }
  
      CAmount GetDustThreshold(const CFeeRate &minRelayTxFee) const
      {
          // "Dust" is defined in terms of CTransaction::minRelayTxFee, which has units COQUITOS-per-kilobyte.
          // If you'd pay more than 1/3 in fees to spend something, then we consider it dust.
          // A typical spendable txout is 34 bytes big, and will need a CTxIn of at least 148 bytes to spend
          // i.e. total is 148 + 34 = 182 bytes. Default -minrelaytxfee is 1000 COQUITOS per kB
          // and that means that fee per spendable txout is 182 * 1000 / 1000 = 182 COQUITOS.
          // So dust is a spendable txout less than 546 * minRelayTxFee / 1000 (in COQUITOS)
          // i.e. 182 * 3 = 546 COQUITOS with default -minrelaytxfee = minRelayTxFee = 1000 COQUITOS per kB.
          if (scriptPubKey.IsUnspendable())
              return 0;
  
          size_t nSize = GetSerializeSize(*this, SER_DISK, 0)+148u;
          return 3*minRelayTxFee.GetFee(nSize);
      }
  
      bool IsDust(const CFeeRate &minRelayTxFee) const
      {
          return (nValue < GetDustThreshold(minRelayTxFee));
      }
  
      friend bool operator==(const CTxOut& a, const CTxOut& b)
      {
          return (a.nValue       == b.nValue &&
                  a.scriptPubKey == b.scriptPubKey &&
                  a.nRounds      == b.nRounds);
      }
  
      friend bool operator!=(const CTxOut& a, const CTxOut& b)
      {
          return !(a == b);
      }
  
      std::string ToString() const;
  };
  
  struct CMutableTransaction;
  
  /** The basic transaction that is broadcasted on the network and contained in
   * blocks.  A transaction can contain multiple inputs and outputs.
   */
  class CTransaction
  {
  public:
      // Default transaction version.
      static const int32_t CURRENT_VERSION=2;
  
      // Changing the default transaction version requires a two step process: first
      // adapting relay policy by bumping MAX_STANDARD_VERSION, and then later date
      // bumping the default CURRENT_VERSION at which point both CURRENT_VERSION and
      // MAX_STANDARD_VERSION will be equal.
      static const int32_t MAX_STANDARD_VERSION=3;
  
      // The local variables are made const to prevent unintended modification
      // without updating the cached hash value. However, CTransaction is not
      // actually immutable; deserialization and assignment are implemented,
      // and bypass the constness. This is safe, as they update the entire
      // structure, including the hash.
      const int16_t nVersion;
      const int16_t nType;
      const std::vector<CTxIn> vin;
      const std::vector<CTxOut> vout;
      const uint32_t nLockTime;
      const std::vector<uint8_t> vExtraPayload; // only available for special transaction types
  
  private:
      /** Memory only. */
      const uint256 hash;
  
      uint256 ComputeHash() const;
  
  public:
      /** Construct a CTransaction that qualifies as IsNull() */
      CTransaction();
  
      /** Convert a CMutableTransaction into a CTransaction. */
      CTransaction(const CMutableTransaction &tx);
      CTransaction(CMutableTransaction &&tx);
  
      template <typename Stream>
      inline void Serialize(Stream& s) const {
          int32_t n32bitVersion = this->nVersion | (this->nType << 16);
          s << n32bitVersion;
          s << vin;
          s << vout;
          s << nLockTime;
          if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL)
              s << vExtraPayload;
      }
  
      /** This deserializing constructor is provided instead of an Unserialize method.
       *  Unserialize is not possible, since it would require overwriting const fields. */
      template <typename Stream>
      CTransaction(deserialize_type, Stream& s) : CTransaction(CMutableTransaction(deserialize, s)) {}
  
      bool IsNull() const {
          return vin.empty() && vout.empty();
      }
  
      const uint256& GetHash() const {
          return hash;
      }
  
      // Return sum of txouts.
      CAmount GetValueOut() const;
      // GetValueIn() is a method on CCoinsViewCache, because
      // inputs must be known to compute value in.
  
      /**
       * Get the total transaction size in bytes, including witness data.
       * "Total Size" defined in BIP141 and BIP144.
       * @return Total transaction size in bytes
       */
      unsigned int GetTotalSize() const;
  
      bool IsCoinBase() const
      {
          return (vin.size() == 1 && vin[0].prevout.IsNull());
      }
  
      friend bool operator==(const CTransaction& a, const CTransaction& b)
      {
          return a.hash == b.hash;
      }
  
      friend bool operator!=(const CTransaction& a, const CTransaction& b)
      {
          return a.hash != b.hash;
      }
  
      std::string ToString() const;
  };
  
  /** A mutable version of CTransaction. */
  struct CMutableTransaction
  {
      int16_t nVersion;
      int16_t nType;
      std::vector<CTxIn> vin;
      std::vector<CTxOut> vout;
      uint32_t nLockTime;
      std::vector<uint8_t> vExtraPayload; // only available for special transaction types
  
      CMutableTransaction();
      CMutableTransaction(const CTransaction& tx);
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action) {
          int32_t n32bitVersion = this->nVersion | (this->nType << 16);
          READWRITE(n32bitVersion);
          if (ser_action.ForRead()) {
              this->nVersion = (int16_t) (n32bitVersion & 0xffff);
              this->nType = (int16_t) ((n32bitVersion >> 16) & 0xffff);
          }
          READWRITE(vin);
          READWRITE(vout);
          READWRITE(nLockTime);
          if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL) {
              READWRITE(vExtraPayload);
          }
      }
  
      template <typename Stream>
      CMutableTransaction(deserialize_type, Stream& s) {
          Unserialize(s);
      }
  
      /** Compute the hash of this CMutableTransaction. This is computed on the
       * fly, as opposed to GetHash() in CTransaction, which uses a cached result.
       */
      uint256 GetHash() const;
  
      std::string ToString() const;
  
      friend bool operator==(const CMutableTransaction& a, const CMutableTransaction& b)
      {
          return a.GetHash() == b.GetHash();
      }
  
      friend bool operator!=(const CMutableTransaction& a, const CMutableTransaction& b)
      {
          return !(a == b);
      }
  
  };
  
  typedef std::shared_ptr<const CTransaction> CTransactionRef;
  static inline CTransactionRef MakeTransactionRef() { return std::make_shared<const CTransaction>(); }
  template <typename Tx> static inline CTransactionRef MakeTransactionRef(Tx&& txIn) { return std::make_shared<const CTransaction>(std::forward<Tx>(txIn)); }
  
  /** Implementation of BIP69
   * https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki
   */
  struct CompareInputBIP69
  {
      inline bool operator()(const CTxIn& a, const CTxIn& b) const
      {
          if (a.prevout.hash == b.prevout.hash) return a.prevout.n < b.prevout.n;
  
          uint256 hasha = a.prevout.hash;
          uint256 hashb = b.prevout.hash;
  
          typedef std::reverse_iterator<const unsigned char*> rev_it;
          rev_it rita = rev_it(hasha.end());
          rev_it ritb = rev_it(hashb.end());
  
          return std::lexicographical_compare(rita, rita + hasha.size(), ritb, ritb + hashb.size());
      }
  };
  
  struct CompareOutputBIP69
  {
      inline bool operator()(const CTxOut& a, const CTxOut& b) const
      {
          return a.nValue < b.nValue || (a.nValue == b.nValue && a.scriptPubKey < b.scriptPubKey);
      }
  };
  
  #endif // BITCOIN_PRIMITIVES_TRANSACTION_H
  