text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2018 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_HASH_H
  #define BITCOIN_HASH_H
  
  #include <crypto/ripemd160.h>
  #include <crypto/sha256.h>
  #include <prevector.h>
  #include <serialize.h>
  #include <uint256.h>
  #include <version.h>
  
  #include <vector>
  
  #include "groestlcoin.h"
  
  typedef uint256 ChainCode;
  
  /** A hasher class for Bitcoin's 256-bit hash (double SHA-256). */
  class CHash256 {
  private:
      CSHA256 sha;
  public:
      static const size_t OUTPUT_SIZE = CSHA256::OUTPUT_SIZE;
  
      void Finalize(unsigned char hash[OUTPUT_SIZE]) {
          unsigned char buf[CSHA256::OUTPUT_SIZE];
          sha.Finalize(buf);
          sha.Reset().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
      }
  
      CHash256& Write(const unsigned char *data, size_t len) {
          sha.Write(data, len);
          return *this;
      }
  
      CHash256& Reset() {
          sha.Reset();
          return *this;
      }
  };
  
  /** A hasher class for Bitcoin's 160-bit hash (SHA-256 + RIPEMD-160). */
  class CHash160 {
  private:
      CSHA256 sha;
  public:
      static const size_t OUTPUT_SIZE = CRIPEMD160::OUTPUT_SIZE;
  
      void Finalize(unsigned char hash[OUTPUT_SIZE]) {
          unsigned char buf[CSHA256::OUTPUT_SIZE];
          sha.Finalize(buf);
          CRIPEMD160().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
      }
  
      CHash160& Write(const unsigned char *data, size_t len) {
          sha.Write(data, len);
          return *this;
      }
  
      CHash160& Reset() {
          sha.Reset();
          return *this;
      }
  };
  
  /** Compute the 256-bit hash of an object. */
  template<typename T1>
  inline uint256 Hash(const T1 pbegin, const T1 pend)
  {
      static const unsigned char pblank[1] = {};
      uint256 result;
      CHash256().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
                .Finalize((unsigned char*)&result);
      return result;
  }
  
  /** Compute the 256-bit hash of the concatenation of two objects. */
  template<typename T1, typename T2>
  inline uint256 Hash(const T1 p1begin, const T1 p1end,
                      const T2 p2begin, const T2 p2end) {
      static const unsigned char pblank[1] = {};
      uint256 result;
      CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
                .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
                .Finalize((unsigned char*)&result);
      return result;
  }
  
  /** Compute the 160-bit hash an object. */
  template<typename T1>
  inline uint160 Hash160(const T1 pbegin, const T1 pend)
  {
      static unsigned char pblank[1] = {};
      uint160 result;
      CHash160().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
                .Finalize((unsigned char*)&result);
      return result;
  }
  
  /** Compute the 160-bit hash of a vector. */
  inline uint160 Hash160(const std::vector<unsigned char>& vch)
  {
      return Hash160(vch.begin(), vch.end());
  }
  
  /** Compute the 160-bit hash of a vector. */
  template<unsigned int N>
  inline uint160 Hash160(const prevector<N, unsigned char>& vch)
  {
      return Hash160(vch.begin(), vch.end());
  }
  
  /** A writer stream (for serialization) that computes a 256-bit hash. */
  class CHashWriter
  {
  private:
      CSHA256 ctx;	//GRS
  
      const int nType;
      const int nVersion;
  public:
  
      CHashWriter(int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn) {}
  
      int GetType() const { return nType; }
      int GetVersion() const { return nVersion; }
  
      void write(const char *pch, size_t size) {
          ctx.Write((const unsigned char*)pch, size);
      }
  
      // invalidates the object
      uint256 GetHash() {
          uint256 result;
          ctx.Finalize((unsigned char*)&result);
          return result;
      }
  
      template<typename T>
      CHashWriter& operator<<(const T& obj) {
          // Serialize to this stream
          ::Serialize(*this, obj);
          return (*this);
      }
  };
  
  /** Reads data from an underlying stream, while hashing the read data. */
  template<typename Source>
  class CHashVerifier : public CHashWriter
  {
  private:
      Source* source;
  
  public:
      explicit CHashVerifier(Source* source_) : CHashWriter(source_->GetType(), source_->GetVersion()), source(source_) {}
  
      void read(char* pch, size_t nSize)
      {
          source->read(pch, nSize);
          this->write(pch, nSize);
      }
  
      void ignore(size_t nSize)
      {
          char data[1024];
          while (nSize > 0) {
              size_t now = std::min<size_t>(nSize, 1024);
              read(data, now);
              nSize -= now;
          }
      }
  
      template<typename T>
      CHashVerifier<Source>& operator>>(T&& obj)
      {
          // Unserialize from this stream
          ::Unserialize(*this, obj);
          return (*this);
      }
  };
  
  /** Compute the 256-bit hash of an object's serialization. */
  template<typename T>
  uint256 SerializeHash(const T& obj, int nType=SER_GETHASH, int nVersion=PROTOCOL_VERSION)
  {
      CHashWriter ss(nType, nVersion);
      ss << obj;
      return ss.GetHash();
  }
  
  unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char>& vDataToHash);
  
  void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]);
  
  /** SipHash-2-4 */
  class CSipHasher
  {
  private:
      uint64_t v[4];
      uint64_t tmp;
      int count;
  
  public:
      /** Construct a SipHash calculator initialized with 128-bit key (k0, k1) */
      CSipHasher(uint64_t k0, uint64_t k1);
      /** Hash a 64-bit integer worth of data
       *  It is treated as if this was the little-endian interpretation of 8 bytes.
       *  This function can only be used when a multiple of 8 bytes have been written so far.
       */
      CSipHasher& Write(uint64_t data);
      /** Hash arbitrary bytes. */
      CSipHasher& Write(const unsigned char* data, size_t size);
      /** Compute the 64-bit SipHash-2-4 of the data written so far. The object remains untouched. */
      uint64_t Finalize() const;
  };
  
  /** Optimized SipHash-2-4 implementation for uint256.
   *
   *  It is identical to:
   *    SipHasher(k0, k1)
   *      .Write(val.GetUint64(0))
   *      .Write(val.GetUint64(1))
   *      .Write(val.GetUint64(2))
   *      .Write(val.GetUint64(3))
   *      .Finalize()
   */
  uint64_t SipHashUint256(uint64_t k0, uint64_t k1, const uint256& val);
  uint64_t SipHashUint256Extra(uint64_t k0, uint64_t k1, const uint256& val, uint32_t extra);
  
  #endif // BITCOIN_HASH_H
  