text: // Copyright (c) 2012-2013 The PPCoin developers
  // Copyright (c) 2015-2019 The PIVX developers
  // Copyright (c) 2018-2019 The Simplicity developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BITCOIN_KERNEL_H
  #define BITCOIN_KERNEL_H
  
  #include "main.h"
  #include "stakeinput.h"
  
  
  // MODIFIER_INTERVAL: time to elapse before new modifier is computed
  static const unsigned int MODIFIER_INTERVAL = 60;
  
  // MODIFIER_INTERVAL_RATIO:
  // ratio of group interval length between the last group and the first group
  static const int MODIFIER_INTERVAL_RATIO = 3;
  
  // Compute the hash modifier for proof-of-stake
  bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int& nStakeModifierHeight, int64_t& nStakeModifierTime, bool fPrintProofOfStake);
  bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier);
  uint256 ComputeStakeModifier(const CBlockIndex* pindexPrev, const uint256& kernel);
  bool Stake(const CBlockIndex* pindexPrev, CStakeInput* stakeInput, unsigned int nBits, unsigned int& nTimeTx, uint256& hashProofOfStake);
  
  // Initialize the stake input object
  bool initStakeInput(const CBlock block, std::unique_ptr<CStakeInput>& stake, int nPreviousBlockHeight);
  
  // Check kernel hash target and coinstake signature
  // Sets hashProofOfStake on success return
  bool CheckProofOfStake(const CBlock block, uint256& hashProofOfStake, std::unique_ptr<CStakeInput>& stake, int nPreviousBlockHeight);
  bool CheckStakeKernelHash(const CBlockIndex* pindexPrev, const unsigned int nBits, CStakeInput* stake, const unsigned int nTimeTx, uint256& hashProofOfStake, const bool fVerify = false);
  // Returns the proof of stake hash
  bool GetHashProofOfStake(const CBlockIndex* pindexPrev, CStakeInput* stake, const unsigned int nTimeTx, const bool fVerify, uint256& hashProofOfStakeRet);
  // Get stake modifier checksum
  unsigned int GetStakeModifierChecksum(const CBlockIndex* pindex);
  
  // Check stake modifier hard checkpoints
  bool CheckStakeModifierCheckpoints(int nHeight, unsigned int nStakeModifierChecksum);
  
  bool ContextualCheckZerocoinStake(int nPreviousBlockHeight, CStakeInput* stake);
  
  // Get time weight using supplied timestamps
  int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd);
  
  #endif // BITCOIN_KERNEL_H
  