feerate.h raw

   1  // Copyright (c) 2009-2010 Satoshi Nakamoto
   2  // Copyright (c) 2009-present The Bitcoin Core developers
   3  // Distributed under the MIT software license, see the accompanying
   4  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5  
   6  #ifndef BITCOIN_POLICY_FEERATE_H
   7  #define BITCOIN_POLICY_FEERATE_H
   8  
   9  #include <consensus/amount.h>
  10  #include <serialize.h>
  11  #include <util/feefrac.h>
  12  #include <util/fees.h>
  13  
  14  
  15  #include <cstdint>
  16  #include <string>
  17  #include <type_traits>
  18  
  19  const std::string CURRENCY_UNIT = "BTC"; // One formatted unit
  20  const std::string CURRENCY_ATOM = "sat"; // One indivisible minimum value unit
  21  
  22  enum class FeeRateFormat {
  23      BTC_KVB, //!< Use BTC/kvB fee rate unit
  24      SAT_VB,  //!< Use sat/vB fee rate unit
  25  };
  26  
  27  /**
  28   * Fee rate in satoshis per virtualbyte: CAmount / vB
  29   * the feerate is represented internally as FeeFrac
  30   */
  31  class CFeeRate
  32  {
  33  private:
  34      /** Fee rate in sats/vB (satoshis per N virtualbytes) */
  35      FeePerVSize m_feerate;
  36  
  37  public:
  38      /** Fee rate of 0 satoshis per 0 vB */
  39      CFeeRate() = default;
  40      template<std::integral I> // Disallow silent float -> int conversion
  41      explicit CFeeRate(const I m_feerate_kvb) : m_feerate(FeePerVSize(m_feerate_kvb, 1000)) {}
  42  
  43      /**
  44       * Construct a fee rate from a fee in satoshis and a vsize in vB.
  45       *
  46       * Passing any virtual_bytes less than or equal to 0 will result in 0 fee rate per 0 size.
  47       */
  48      CFeeRate(const CAmount& nFeePaid, int32_t virtual_bytes);
  49  
  50      /**
  51       * Return the fee in satoshis for the given vsize in vbytes.
  52       * If the calculated fee would have fractional satoshis, then the
  53       * returned fee will always be rounded up to the nearest satoshi.
  54       */
  55      CAmount GetFee(int32_t virtual_bytes) const;
  56  
  57      FeePerVSize GetFeePerVSize() const { return m_feerate; }
  58  
  59      /**
  60       * Return the fee in satoshis for a vsize of 1000 vbytes
  61       */
  62      CAmount GetFeePerK() const { return CAmount(m_feerate.EvaluateFeeDown(1000)); }
  63      friend std::strong_ordering operator<=>(const CFeeRate& a, const CFeeRate& b) noexcept
  64      {
  65          return ByRatio{a.m_feerate} <=> ByRatio{b.m_feerate};
  66      }
  67      friend bool operator==(const CFeeRate& a, const CFeeRate& b) noexcept
  68      {
  69          return ByRatio{a.m_feerate} == ByRatio{b.m_feerate};
  70      }
  71      CFeeRate& operator+=(const CFeeRate& a) {
  72          m_feerate = FeePerVSize(GetFeePerK() + a.GetFeePerK(), 1000);
  73          return *this;
  74      }
  75      std::string ToString(FeeRateFormat fee_rate_format = FeeRateFormat::BTC_KVB) const;
  76      friend CFeeRate operator*(const CFeeRate& f, int a) { return CFeeRate(a * f.m_feerate.fee, f.m_feerate.size); }
  77      friend CFeeRate operator*(int a, const CFeeRate& f) { return CFeeRate(a * f.m_feerate.fee, f.m_feerate.size); }
  78  
  79      SERIALIZE_METHODS(CFeeRate, obj) { READWRITE(obj.m_feerate.fee, obj.m_feerate.size); }
  80  };
  81  
  82  #endif // BITCOIN_POLICY_FEERATE_H
  83