text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2016 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_AMOUNT_H
  #define BITCOIN_AMOUNT_H
  
  #include "serialize.h"
  
  #include <cstdlib>
  #include <string>
  
  /** Amount in satoshis (Can be negative) */
  typedef int64_t CAmount;
  
  static const CAmount COIN = 100000000;
  static const CAmount CENT = 1000000;
  
  extern const std::string CURRENCY_UNIT;
  
  /**
   * No amount larger than this (in satoshi) is valid.
   *
   * Note that this constant is *not* the total money supply, which in Bitcoin
   * currently happens to be less than 21,000,000 BCC for various reasons, but
   * rather a sanity check. As this sanity check is used by consensus-critical
   * validation code, the exact value of the MAX_MONEY constant is consensus
   * critical; in unusual circumstances like a(nother) overflow bug that allowed
   * for the creation of coins out of thin air modification could lead to a fork.
   */
  static const CAmount MAX_MONEY = 21000000 * COIN;
  inline bool MoneyRange(const CAmount &nValue) {
      return (nValue >= 0 && nValue <= MAX_MONEY);
  }
  
  /**
   * Fee rate in satoshis per kilobyte: CAmount / kB
   */
  class CFeeRate {
  private:
      // unit is satoshis-per-1,000-bytes
      CAmount nSatoshisPerK;
  
  public:
      /** Fee rate of 0 satoshis per kB */
      CFeeRate() : nSatoshisPerK(0) {}
      explicit CFeeRate(const CAmount &_nSatoshisPerK)
          : nSatoshisPerK(_nSatoshisPerK) {}
      /**
       * Constructor for a fee rate in satoshis per kB. The size in bytes must not
       * exceed (2^63 - 1)
       */
      CFeeRate(const CAmount &nFeePaid, size_t nBytes);
      CFeeRate(const CFeeRate &other) { nSatoshisPerK = other.nSatoshisPerK; }
      /**
       * Return the fee in satoshis for the given size in bytes.
       */
      CAmount GetFee(size_t nBytes) const;
      /**
       * Return the fee in satoshis for a size of 1000 bytes
       */
      CAmount GetFeePerK() const { return GetFee(1000); }
      friend bool operator<(const CFeeRate &a, const CFeeRate &b) {
          return a.nSatoshisPerK < b.nSatoshisPerK;
      }
      friend bool operator>(const CFeeRate &a, const CFeeRate &b) {
          return a.nSatoshisPerK > b.nSatoshisPerK;
      }
      friend bool operator==(const CFeeRate &a, const CFeeRate &b) {
          return a.nSatoshisPerK == b.nSatoshisPerK;
      }
      friend bool operator<=(const CFeeRate &a, const CFeeRate &b) {
          return a.nSatoshisPerK <= b.nSatoshisPerK;
      }
      friend bool operator>=(const CFeeRate &a, const CFeeRate &b) {
          return a.nSatoshisPerK >= b.nSatoshisPerK;
      }
      CFeeRate &operator+=(const CFeeRate &a) {
          nSatoshisPerK += a.nSatoshisPerK;
          return *this;
      }
      std::string ToString() const;
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream &s, Operation ser_action) {
          READWRITE(nSatoshisPerK);
      }
  };
  
  #endif //  BITCOIN_AMOUNT_H
  