text: // Copyright (c) 2012-2013 The PPCoin developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  #ifndef PPCOIN_KERNEL_H
  #define PPCOIN_KERNEL_H
  
  #include <main.h>
  
  // To decrease granularity of timestamp
  // Supposed to be 2^n-1
  static const int STAKE_TIMESTAMP_MASK = 15;
  
  // MODIFIER_INTERVAL: time to elapse before new modifier is computed
  extern unsigned int nModifierInterval;
  
  // 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 ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64_t& nStakeModifier, bool& fGeneratedStakeModifier);
  uint256 ComputeStakeModifierV2(const CBlockIndex* pindexPrev, const uint256& kernel);
  
  // Check whether stake kernel meets hash target
  // Sets hashProofOfStake on success return
  bool CheckStakeKernelHash(CBlockIndex* pindexPrev, unsigned int nBits, const CBlock& blockFrom, unsigned int nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, uint256& hashProofOfStake, uint256& targetProofOfStake, bool fPrintProofOfStake=false);
  
  // Check kernel hash target and coinstake signature
  // Sets hashProofOfStake on success return
  bool CheckProofOfStake(CBlockIndex* pindexPrev, const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake);
  
  // Check whether the coinstake timestamp meets protocol
  bool CheckCoinStakeTimestamp(int nHeight, int64_t nTimeBlock, int64_t nTimeTx);
  
  // Get time weight using supplied timestamps
  int64_t GetWeight(int64_t nIntervalBeginning, int64_t nIntervalEnd);
  
  // Wrapper around CheckStakeKernelHash()
  // Also checks existence of kernel input and min age
  // Convenient for searching a kernel
  bool CheckKernel(CBlockIndex* pindexPrev, unsigned int nBits, int64_t nTime, const COutPoint& prevout, int64_t* pBlockTime = NULL);
  
  #endif // PPCOIN_KERNEL_H
  