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_SERIALIZE_H
  #define BITCOIN_SERIALIZE_H
  
  #include <compat/endian.h>
  
  #include <algorithm>
  #include <assert.h>
  #include <ios>
  #include <limits>
  #include <map>
  #include <memory>
  #include <set>
  #include <stdint.h>
  #include <string>
  #include <string.h>
  #include <utility>
  #include <vector>
  
  #include <prevector.h>
  #include <span.h>
  
  static const unsigned int MAX_SIZE = 0x10000000; // Metrix: Increase max serialized size to 256mb
  
  /**
   * Dummy data type to identify deserializing constructors.
   *
   * By convention, a constructor of a type T with signature
   *
   *   template <typename Stream> T::T(deserialize_type, Stream& s)
   *
   * is a deserializing constructor, which builds the type by
   * deserializing it from s. If T contains const fields, this
   * is likely the only way to do so.
   */
  struct deserialize_type {};
  constexpr deserialize_type deserialize {};
  
  /**
   * Used to bypass the rule against non-const reference to temporary
   * where it makes sense with wrappers.
   */
  template<typename T>
  inline T& REF(const T& val)
  {
      return const_cast<T&>(val);
  }
  
  /**
   * Used to acquire a non-const pointer "this" to generate bodies
   * of const serialization operations from a template
   */
  template<typename T>
  inline T* NCONST_PTR(const T* val)
  {
      return const_cast<T*>(val);
  }
  
  //! Safely convert odd char pointer types to standard ones.
  inline char* CharCast(char* c) { return c; }
  inline char* CharCast(unsigned char* c) { return (char*)c; }
  inline const char* CharCast(const char* c) { return c; }
  inline const char* CharCast(const unsigned char* c) { return (const char*)c; }
  
  /*
   * Lowest-level serialization and conversion.
   * @note Sizes of these types are verified in the tests
   */
  template<typename Stream> inline void ser_writedata8(Stream &s, uint8_t obj)
  {
      s.write((char*)&obj, 1);
  }
  template<typename Stream> inline void ser_writedata16(Stream &s, uint16_t obj)
  {
      obj = htole16(obj);
      s.write((char*)&obj, 2);
  }
  template<typename Stream> inline void ser_writedata16be(Stream &s, uint16_t obj)
  {
      obj = htobe16(obj);
      s.write((char*)&obj, 2);
  }
  template<typename Stream> inline void ser_writedata32(Stream &s, uint32_t obj)
  {
      obj = htole32(obj);
      s.write((char*)&obj, 4);
  }
  template<typename Stream> inline void ser_writedata32be(Stream &s, uint32_t obj)
  {
      obj = htobe32(obj);
      s.write((char*)&obj, 4);
  }
  template<typename Stream> inline void ser_writedata64(Stream &s, uint64_t obj)
  {
      obj = htole64(obj);
      s.write((char*)&obj, 8);
  }
  template<typename Stream> inline uint8_t ser_readdata8(Stream &s)
  {
      uint8_t obj;
      s.read((char*)&obj, 1);
      return obj;
  }
  template<typename Stream> inline uint16_t ser_readdata16(Stream &s)
  {
      uint16_t obj;
      s.read((char*)&obj, 2);
      return le16toh(obj);
  }
  template<typename Stream> inline uint16_t ser_readdata16be(Stream &s)
  {
      uint16_t obj;
      s.read((char*)&obj, 2);
      return be16toh(obj);
  }
  template<typename Stream> inline uint32_t ser_readdata32(Stream &s)
  {
      uint32_t obj;
      s.read((char*)&obj, 4);
      return le32toh(obj);
  }
  template<typename Stream> inline uint32_t ser_readdata32be(Stream &s)
  {
      uint32_t obj;
      s.read((char*)&obj, 4);
      return be32toh(obj);
  }
  template<typename Stream> inline uint64_t ser_readdata64(Stream &s)
  {
      uint64_t obj;
      s.read((char*)&obj, 8);
      return le64toh(obj);
  }
  inline uint64_t ser_double_to_uint64(double x)
  {
      union { double x; uint64_t y; } tmp;
      tmp.x = x;
      return tmp.y;
  }
  inline uint32_t ser_float_to_uint32(float x)
  {
      union { float x; uint32_t y; } tmp;
      tmp.x = x;
      return tmp.y;
  }
  inline double ser_uint64_to_double(uint64_t y)
  {
      union { double x; uint64_t y; } tmp;
      tmp.y = y;
      return tmp.x;
  }
  inline float ser_uint32_to_float(uint32_t y)
  {
      union { float x; uint32_t y; } tmp;
      tmp.y = y;
      return tmp.x;
  }
  
  
  /////////////////////////////////////////////////////////////////
  //
  // Templates for serializing to anything that looks like a stream,
  // i.e. anything that supports .read(char*, size_t) and .write(char*, size_t)
  //
  
  class CSizeComputer;
  
  enum
  {
      // primary actions
      SER_NETWORK         = (1 << 0),
      SER_DISK            = (1 << 1),
      SER_GETHASH         = (1 << 2),
  };
  
  //! Convert the reference base type to X, without changing constness or reference type.
  template<typename X> X& ReadWriteAsHelper(X& x) { return x; }
  template<typename X> const X& ReadWriteAsHelper(const X& x) { return x; }
  
  #define READWRITE(...) (::SerReadWriteMany(s, ser_action, __VA_ARGS__))
  #define READWRITEAS(type, obj) (::SerReadWriteMany(s, ser_action, ReadWriteAsHelper<type>(obj)))
  
  /**
   * Implement three methods for serializable objects. These are actually wrappers over
   * "SerializationOp" template, which implements the body of each class' serialization
   * code. Adding "ADD_SERIALIZE_METHODS" in the body of the class causes these wrappers to be
   * added as members.
   */
  #define ADD_SERIALIZE_METHODS                                         \
      template<typename Stream>                                         \
      void Serialize(Stream& s) const {                                 \
          NCONST_PTR(this)->SerializationOp(s, CSerActionSerialize());  \
      }                                                                 \
      template<typename Stream>                                         \
      void Unserialize(Stream& s) {                                     \
          SerializationOp(s, CSerActionUnserialize());                  \
      }
  
  #ifndef CHAR_EQUALS_INT8
  template<typename Stream> inline void Serialize(Stream& s, char a    ) { ser_writedata8(s, a); } // TODO Get rid of bare char
  #endif
  template<typename Stream> inline void Serialize(Stream& s, int8_t a  ) { ser_writedata8(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, uint8_t a ) { ser_writedata8(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, int16_t a ) { ser_writedata16(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, uint16_t a) { ser_writedata16(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, int32_t a ) { ser_writedata32(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, uint32_t a) { ser_writedata32(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, int64_t a ) { ser_writedata64(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, uint64_t a) { ser_writedata64(s, a); }
  template<typename Stream> inline void Serialize(Stream& s, float a   ) { ser_writedata32(s, ser_float_to_uint32(a)); }
  template<typename Stream> inline void Serialize(Stream& s, double a  ) { ser_writedata64(s, ser_double_to_uint64(a)); }
  template<typename Stream, int N> inline void Serialize(Stream& s, const char (&a)[N]) { s.write(a, N); }
  template<typename Stream, int N> inline void Serialize(Stream& s, const unsigned char (&a)[N]) { s.write(CharCast(a), N); }
  template<typename Stream> inline void Serialize(Stream& s, const Span<const unsigned char>& span) { s.write(CharCast(span.data()), span.size()); }
  template<typename Stream> inline void Serialize(Stream& s, const Span<unsigned char>& span) { s.write(CharCast(span.data()), span.size()); }
  
  #ifndef CHAR_EQUALS_INT8
  template<typename Stream> inline void Unserialize(Stream& s, char& a    ) { a = ser_readdata8(s); } // TODO Get rid of bare char
  #endif
  template<typename Stream> inline void Unserialize(Stream& s, int8_t& a  ) { a = ser_readdata8(s); }
  template<typename Stream> inline void Unserialize(Stream& s, uint8_t& a ) { a = ser_readdata8(s); }
  template<typename Stream> inline void Unserialize(Stream& s, int16_t& a ) { a = ser_readdata16(s); }
  template<typename Stream> inline void Unserialize(Stream& s, uint16_t& a) { a = ser_readdata16(s); }
  template<typename Stream> inline void Unserialize(Stream& s, int32_t& a ) { a = ser_readdata32(s); }
  template<typename Stream> inline void Unserialize(Stream& s, uint32_t& a) { a = ser_readdata32(s); }
  template<typename Stream> inline void Unserialize(Stream& s, int64_t& a ) { a = ser_readdata64(s); }
  template<typename Stream> inline void Unserialize(Stream& s, uint64_t& a) { a = ser_readdata64(s); }
  template<typename Stream> inline void Unserialize(Stream& s, float& a   ) { a = ser_uint32_to_float(ser_readdata32(s)); }
  template<typename Stream> inline void Unserialize(Stream& s, double& a  ) { a = ser_uint64_to_double(ser_readdata64(s)); }
  template<typename Stream, int N> inline void Unserialize(Stream& s, char (&a)[N]) { s.read(a, N); }
  template<typename Stream, int N> inline void Unserialize(Stream& s, unsigned char (&a)[N]) { s.read(CharCast(a), N); }
  template<typename Stream> inline void Unserialize(Stream& s, Span<unsigned char>& span) { s.read(CharCast(span.data()), span.size()); }
  
  template<typename Stream> inline void Serialize(Stream& s, bool a)    { char f=a; ser_writedata8(s, f); }
  template<typename Stream> inline void Unserialize(Stream& s, bool& a) { char f=ser_readdata8(s); a=f; }
  
  
  
  
  
  
  /**
   * Compact Size
   * size <  253        -- 1 byte
   * size <= USHRT_MAX  -- 3 bytes  (253 + 2 bytes)
   * size <= UINT_MAX   -- 5 bytes  (254 + 4 bytes)
   * size >  UINT_MAX   -- 9 bytes  (255 + 8 bytes)
   */
  inline unsigned int GetSizeOfCompactSize(uint64_t nSize)
  {
      if (nSize < 253)             return sizeof(unsigned char);
      else if (nSize <= std::numeric_limits<unsigned short>::max()) return sizeof(unsigned char) + sizeof(unsigned short);
      else if (nSize <= std::numeric_limits<unsigned int>::max())  return sizeof(unsigned char) + sizeof(unsigned int);
      else                         return sizeof(unsigned char) + sizeof(uint64_t);
  }
  
  inline void WriteCompactSize(CSizeComputer& os, uint64_t nSize);
  
  template<typename Stream>
  void WriteCompactSize(Stream& os, uint64_t nSize)
  {
      if (nSize < 253)
      {
          ser_writedata8(os, nSize);
      }
      else if (nSize <= std::numeric_limits<unsigned short>::max())
      {
          ser_writedata8(os, 253);
          ser_writedata16(os, nSize);
      }
      else if (nSize <= std::numeric_limits<unsigned int>::max())
      {
          ser_writedata8(os, 254);
          ser_writedata32(os, nSize);
      }
      else
      {
          ser_writedata8(os, 255);
          ser_writedata64(os, nSize);
      }
      return;
  }
  
  template<typename Stream>
  uint64_t ReadCompactSize(Stream& is)
  {
      uint8_t chSize = ser_readdata8(is);
      uint64_t nSizeRet = 0;
      if (chSize < 253)
      {
          nSizeRet = chSize;
      }
      else if (chSize == 253)
      {
          nSizeRet = ser_readdata16(is);
          if (nSizeRet < 253)
              throw std::ios_base::failure("non-canonical ReadCompactSize()");
      }
      else if (chSize == 254)
      {
          nSizeRet = ser_readdata32(is);
          if (nSizeRet < 0x10000u)
              throw std::ios_base::failure("non-canonical ReadCompactSize()");
      }
      else
      {
          nSizeRet = ser_readdata64(is);
          if (nSizeRet < 0x100000000ULL)
              throw std::ios_base::failure("non-canonical ReadCompactSize()");
      }
      if (nSizeRet > (uint64_t)MAX_SIZE)
          throw std::ios_base::failure("ReadCompactSize(): size too large");
      return nSizeRet;
  }
  
  /**
   * Variable-length integers: bytes are a MSB base-128 encoding of the number.
   * The high bit in each byte signifies whether another digit follows. To make
   * sure the encoding is one-to-one, one is subtracted from all but the last digit.
   * Thus, the byte sequence a[] with length len, where all but the last byte
   * has bit 128 set, encodes the number:
   *
   *  (a[len-1] & 0x7F) + sum(i=1..len-1, 128^i*((a[len-i-1] & 0x7F)+1))
   *
   * Properties:
   * * Very small (0-127: 1 byte, 128-16511: 2 bytes, 16512-2113663: 3 bytes)
   * * Every integer has exactly one encoding
   * * Encoding does not depend on size of original integer type
   * * No redundancy: every (infinite) byte sequence corresponds to a list
   *   of encoded integers.
   *
   * 0:         [0x00]  256:        [0x81 0x00]
   * 1:         [0x01]  16383:      [0xFE 0x7F]
   * 127:       [0x7F]  16384:      [0xFF 0x00]
   * 128:  [0x80 0x00]  16511:      [0xFF 0x7F]
   * 255:  [0x80 0x7F]  65535: [0x82 0xFE 0x7F]
   * 2^32:           [0x8E 0xFE 0xFE 0xFF 0x00]
   */
  
  /**
   * Mode for encoding VarInts.
   *
   * Currently there is no support for signed encodings. The default mode will not
   * compile with signed values, and the legacy "nonnegative signed" mode will
   * accept signed values, but improperly encode and decode them if they are
   * negative. In the future, the DEFAULT mode could be extended to support
   * negative numbers in a backwards compatible way, and additional modes could be
   * added to support different varint formats (e.g. zigzag encoding).
   */
  enum class VarIntMode { DEFAULT, NONNEGATIVE_SIGNED };
  
  template <VarIntMode Mode, typename I>
  struct CheckVarIntMode {
      constexpr CheckVarIntMode()
      {
          static_assert(Mode != VarIntMode::DEFAULT || std::is_unsigned<I>::value, "Unsigned type required with mode DEFAULT.");
          static_assert(Mode != VarIntMode::NONNEGATIVE_SIGNED || std::is_signed<I>::value, "Signed type required with mode NONNEGATIVE_SIGNED.");
      }
  };
  
  template<VarIntMode Mode, typename I>
  inline unsigned int GetSizeOfVarInt(I n)
  {
      CheckVarIntMode<Mode, I>();
      int nRet = 0;
      while(true) {
          nRet++;
          if (n <= 0x7F)
              break;
          n = (n >> 7) - 1;
      }
      return nRet;
  }
  
  template<typename I>
  inline void WriteVarInt(CSizeComputer& os, I n);
  
  template<typename Stream, VarIntMode Mode, typename I>
  void WriteVarInt(Stream& os, I n)
  {
      CheckVarIntMode<Mode, I>();
      unsigned char tmp[(sizeof(n)*8+6)/7];
      int len=0;
      while(true) {
          tmp[len] = (n & 0x7F) | (len ? 0x80 : 0x00);
          if (n <= 0x7F)
              break;
          n = (n >> 7) - 1;
          len++;
      }
      do {
          ser_writedata8(os, tmp[len]);
      } while(len--);
  }
  
  template<typename Stream, VarIntMode Mode, typename I>
  I ReadVarInt(Stream& is)
  {
      CheckVarIntMode<Mode, I>();
      I n = 0;
      while(true) {
          unsigned char chData = ser_readdata8(is);
          if (n > (std::numeric_limits<I>::max() >> 7)) {
             throw std::ios_base::failure("ReadVarInt(): size too large");
          }
          n = (n << 7) | (chData & 0x7F);
          if (chData & 0x80) {
              if (n == std::numeric_limits<I>::max()) {
                  throw std::ios_base::failure("ReadVarInt(): size too large");
              }
              n++;
          } else {
              return n;
          }
      }
  }
  
  #define VARINT(obj, ...) WrapVarInt<__VA_ARGS__>(REF(obj))
  #define COMPACTSIZE(obj) CCompactSize(REF(obj))
  #define LIMITED_STRING(obj,n) LimitedString< n >(REF(obj))
  
  template<VarIntMode Mode, typename I>
  class CVarInt
  {
  protected:
      I &n;
  public:
      explicit CVarInt(I& nIn) : n(nIn) { }
  
      template<typename Stream>
      void Serialize(Stream &s) const {
          WriteVarInt<Stream,Mode,I>(s, n);
      }
  
      template<typename Stream>
      void Unserialize(Stream& s) {
          n = ReadVarInt<Stream,Mode,I>(s);
      }
  };
  
  /** Serialization wrapper class for big-endian integers.
   *
   * Use this wrapper around integer types that are stored in memory in native
   * byte order, but serialized in big endian notation. This is only intended
   * to implement serializers that are compatible with existing formats, and
   * its use is not recommended for new data structures.
   *
   * Only 16-bit types are supported for now.
   */
  template<typename I>
  class BigEndian
  {
  protected:
      I& m_val;
  public:
      explicit BigEndian(I& val) : m_val(val)
      {
          static_assert(std::is_unsigned<I>::value, "BigEndian type must be unsigned integer");
          static_assert(sizeof(I) == 2 && std::numeric_limits<I>::min() == 0 && std::numeric_limits<I>::max() == std::numeric_limits<uint16_t>::max(), "Unsupported BigEndian size");
      }
  
      template<typename Stream>
      void Serialize(Stream& s) const
      {
          ser_writedata16be(s, m_val);
      }
  
      template<typename Stream>
      void Unserialize(Stream& s)
      {
          m_val = ser_readdata16be(s);
      }
  };
  
  class CCompactSize
  {
  protected:
      uint64_t &n;
  public:
      explicit CCompactSize(uint64_t& nIn) : n(nIn) { }
  
      template<typename Stream>
      void Serialize(Stream &s) const {
          WriteCompactSize<Stream>(s, n);
      }
  
      template<typename Stream>
      void Unserialize(Stream& s) {
          n = ReadCompactSize<Stream>(s);
      }
  };
  
  template<size_t Limit>
  class LimitedString
  {
  protected:
      std::string& string;
  public:
      explicit LimitedString(std::string& _string) : string(_string) {}
  
      template<typename Stream>
      void Unserialize(Stream& s)
      {
          size_t size = ReadCompactSize(s);
          if (size > Limit) {
              throw std::ios_base::failure("String length limit exceeded");
          }
          string.resize(size);
          if (size != 0)
              s.read((char*)string.data(), size);
      }
  
      template<typename Stream>
      void Serialize(Stream& s) const
      {
          WriteCompactSize(s, string.size());
          if (!string.empty())
              s.write((char*)string.data(), string.size());
      }
  };
  
  template<VarIntMode Mode=VarIntMode::DEFAULT, typename I>
  CVarInt<Mode, I> WrapVarInt(I& n) { return CVarInt<Mode, I>{n}; }
  
  template<typename I>
  BigEndian<I> WrapBigEndian(I& n) { return BigEndian<I>(n); }
  
  /**
   * Forward declarations
   */
  
  /**
   *  string
   */
  template<typename Stream, typename C> void Serialize(Stream& os, const std::basic_string<C>& str);
  template<typename Stream, typename C> void Unserialize(Stream& is, std::basic_string<C>& str);
  
  /**
   * prevector
   * prevectors of unsigned char are a special case and are intended to be serialized as a single opaque blob.
   */
  template<typename Stream, unsigned int N, typename T> void Serialize_impl(Stream& os, const prevector<N, T>& v, const unsigned char&);
  template<typename Stream, unsigned int N, typename T, typename V> void Serialize_impl(Stream& os, const prevector<N, T>& v, const V&);
  template<typename Stream, unsigned int N, typename T> inline void Serialize(Stream& os, const prevector<N, T>& v);
  template<typename Stream, unsigned int N, typename T> void Unserialize_impl(Stream& is, prevector<N, T>& v, const unsigned char&);
  template<typename Stream, unsigned int N, typename T, typename V> void Unserialize_impl(Stream& is, prevector<N, T>& v, const V&);
  template<typename Stream, unsigned int N, typename T> inline void Unserialize(Stream& is, prevector<N, T>& v);
  
  /**
   * vector
   * vectors of unsigned char are a special case and are intended to be serialized as a single opaque blob.
   */
  template<typename Stream, typename T, typename A> void Serialize_impl(Stream& os, const std::vector<T, A>& v, const unsigned char&);
  template<typename Stream, typename T, typename A> void Serialize_impl(Stream& os, const std::vector<T, A>& v, const bool&);
  template<typename Stream, typename T, typename A, typename V> void Serialize_impl(Stream& os, const std::vector<T, A>& v, const V&);
  template<typename Stream, typename T, typename A> inline void Serialize(Stream& os, const std::vector<T, A>& v);
  template<typename Stream, typename T, typename A> void Unserialize_impl(Stream& is, std::vector<T, A>& v, const unsigned char&);
  template<typename Stream, typename T, typename A, typename V> void Unserialize_impl(Stream& is, std::vector<T, A>& v, const V&);
  template<typename Stream, typename T, typename A> inline void Unserialize(Stream& is, std::vector<T, A>& v);
  
  /**
   * pair
   */
  template<typename Stream, typename K, typename T> void Serialize(Stream& os, const std::pair<K, T>& item);
  template<typename Stream, typename K, typename T> void Unserialize(Stream& is, std::pair<K, T>& item);
  
  /**
   * map
   */
  template<typename Stream, typename K, typename T, typename Pred, typename A> void Serialize(Stream& os, const std::map<K, T, Pred, A>& m);
  template<typename Stream, typename K, typename T, typename Pred, typename A> void Unserialize(Stream& is, std::map<K, T, Pred, A>& m);
  
  /**
   * set
   */
  template<typename Stream, typename K, typename Pred, typename A> void Serialize(Stream& os, const std::set<K, Pred, A>& m);
  template<typename Stream, typename K, typename Pred, typename A> void Unserialize(Stream& is, std::set<K, Pred, A>& m);
  
  /**
   * shared_ptr
   */
  template<typename Stream, typename T> void Serialize(Stream& os, const std::shared_ptr<const T>& p);
  template<typename Stream, typename T> void Unserialize(Stream& os, std::shared_ptr<const T>& p);
  
  /**
   * unique_ptr
   */
  template<typename Stream, typename T> void Serialize(Stream& os, const std::unique_ptr<const T>& p);
  template<typename Stream, typename T> void Unserialize(Stream& os, std::unique_ptr<const T>& p);
  
  
  
  /**
   * If none of the specialized versions above matched, default to calling member function.
   */
  template<typename Stream, typename T>
  inline void Serialize(Stream& os, const T& a)
  {
      a.Serialize(os);
  }
  
  template<typename Stream, typename T>
  inline void Unserialize(Stream& is, T&& a)
  {
      a.Unserialize(is);
  }
  
  
  
  
  
  /**
   * string
   */
  template<typename Stream, typename C>
  void Serialize(Stream& os, const std::basic_string<C>& str)
  {
      WriteCompactSize(os, str.size());
      if (!str.empty())
          os.write((char*)str.data(), str.size() * sizeof(C));
  }
  
  template<typename Stream, typename C>
  void Unserialize(Stream& is, std::basic_string<C>& str)
  {
      unsigned int nSize = ReadCompactSize(is);
      str.resize(nSize);
      if (nSize != 0)
          is.read((char*)str.data(), nSize * sizeof(C));
  }
  
  
  
  /**
   * prevector
   */
  template<typename Stream, unsigned int N, typename T>
  void Serialize_impl(Stream& os, const prevector<N, T>& v, const unsigned char&)
  {
      WriteCompactSize(os, v.size());
      if (!v.empty())
          os.write((char*)v.data(), v.size() * sizeof(T));
  }
  
  template<typename Stream, unsigned int N, typename T, typename V>
  void Serialize_impl(Stream& os, const prevector<N, T>& v, const V&)
  {
      WriteCompactSize(os, v.size());
      for (typename prevector<N, T>::const_iterator vi = v.begin(); vi != v.end(); ++vi)
          ::Serialize(os, (*vi));
  }
  
  template<typename Stream, unsigned int N, typename T>
  inline void Serialize(Stream& os, const prevector<N, T>& v)
  {
      Serialize_impl(os, v, T());
  }
  
  
  template<typename Stream, unsigned int N, typename T>
  void Unserialize_impl(Stream& is, prevector<N, T>& v, const unsigned char&)
  {
      // Limit size per read so bogus size value won't cause out of memory
      v.clear();
      unsigned int nSize = ReadCompactSize(is);
      unsigned int i = 0;
      while (i < nSize)
      {
          unsigned int blk = std::min(nSize - i, (unsigned int)(1 + 4999999 / sizeof(T)));
          v.resize_uninitialized(i + blk);
          is.read((char*)&v[i], blk * sizeof(T));
          i += blk;
      }
  }
  
  template<typename Stream, unsigned int N, typename T, typename V>
  void Unserialize_impl(Stream& is, prevector<N, T>& v, const V&)
  {
      v.clear();
      unsigned int nSize = ReadCompactSize(is);
      unsigned int i = 0;
      unsigned int nMid = 0;
      while (nMid < nSize)
      {
          nMid += 5000000 / sizeof(T);
          if (nMid > nSize)
              nMid = nSize;
          v.resize_uninitialized(nMid);
          for (; i < nMid; ++i)
              Unserialize(is, v[i]);
      }
  }
  
  template<typename Stream, unsigned int N, typename T>
  inline void Unserialize(Stream& is, prevector<N, T>& v)
  {
      Unserialize_impl(is, v, T());
  }
  
  
  
  /**
   * vector
   */
  template<typename Stream, typename T, typename A>
  void Serialize_impl(Stream& os, const std::vector<T, A>& v, const unsigned char&)
  {
      WriteCompactSize(os, v.size());
      if (!v.empty())
          os.write((char*)v.data(), v.size() * sizeof(T));
  }
  
  template<typename Stream, typename T, typename A>
  void Serialize_impl(Stream& os, const std::vector<T, A>& v, const bool&)
  {
      // A special case for std::vector<bool>, as dereferencing
      // std::vector<bool>::const_iterator does not result in a const bool&
      // due to std::vector's special casing for bool arguments.
      WriteCompactSize(os, v.size());
      for (bool elem : v) {
          ::Serialize(os, elem);
      }
  }
  
  template<typename Stream, typename T, typename A, typename V>
  void Serialize_impl(Stream& os, const std::vector<T, A>& v, const V&)
  {
      WriteCompactSize(os, v.size());
      for (typename std::vector<T, A>::const_iterator vi = v.begin(); vi != v.end(); ++vi)
          ::Serialize(os, (*vi));
  }
  
  template<typename Stream, typename T, typename A>
  inline void Serialize(Stream& os, const std::vector<T, A>& v)
  {
      Serialize_impl(os, v, T());
  }
  
  
  template<typename Stream, typename T, typename A>
  void Unserialize_impl(Stream& is, std::vector<T, A>& v, const unsigned char&)
  {
      // Limit size per read so bogus size value won't cause out of memory
      v.clear();
      unsigned int nSize = ReadCompactSize(is);
      unsigned int i = 0;
      while (i < nSize)
      {
          unsigned int blk = std::min(nSize - i, (unsigned int)(1 + 4999999 / sizeof(T)));
          v.resize(i + blk);
          is.read((char*)&v[i], blk * sizeof(T));
          i += blk;
      }
  }
  
  template<typename Stream, typename T, typename A, typename V>
  void Unserialize_impl(Stream& is, std::vector<T, A>& v, const V&)
  {
      v.clear();
      unsigned int nSize = ReadCompactSize(is);
      unsigned int i = 0;
      unsigned int nMid = 0;
      while (nMid < nSize)
      {
          nMid += 5000000 / sizeof(T);
          if (nMid > nSize)
              nMid = nSize;
          v.resize(nMid);
          for (; i < nMid; i++)
              Unserialize(is, v[i]);
      }
  }
  
  template<typename Stream, typename T, typename A>
  inline void Unserialize(Stream& is, std::vector<T, A>& v)
  {
      Unserialize_impl(is, v, T());
  }
  
  
  
  /**
   * pair
   */
  template<typename Stream, typename K, typename T>
  void Serialize(Stream& os, const std::pair<K, T>& item)
  {
      Serialize(os, item.first);
      Serialize(os, item.second);
  }
  
  template<typename Stream, typename K, typename T>
  void Unserialize(Stream& is, std::pair<K, T>& item)
  {
      Unserialize(is, item.first);
      Unserialize(is, item.second);
  }
  
  
  
  /**
   * map
   */
  template<typename Stream, typename K, typename T, typename Pred, typename A>
  void Serialize(Stream& os, const std::map<K, T, Pred, A>& m)
  {
      WriteCompactSize(os, m.size());
      for (const auto& entry : m)
          Serialize(os, entry);
  }
  
  template<typename Stream, typename K, typename T, typename Pred, typename A>
  void Unserialize(Stream& is, std::map<K, T, Pred, A>& m)
  {
      m.clear();
      unsigned int nSize = ReadCompactSize(is);
      typename std::map<K, T, Pred, A>::iterator mi = m.begin();
      for (unsigned int i = 0; i < nSize; i++)
      {
          std::pair<K, T> item;
          Unserialize(is, item);
          mi = m.insert(mi, item);
      }
  }
  
  
  
  /**
   * set
   */
  template<typename Stream, typename K, typename Pred, typename A>
  void Serialize(Stream& os, const std::set<K, Pred, A>& m)
  {
      WriteCompactSize(os, m.size());
      for (typename std::set<K, Pred, A>::const_iterator it = m.begin(); it != m.end(); ++it)
          Serialize(os, (*it));
  }
  
  template<typename Stream, typename K, typename Pred, typename A>
  void Unserialize(Stream& is, std::set<K, Pred, A>& m)
  {
      m.clear();
      unsigned int nSize = ReadCompactSize(is);
      typename std::set<K, Pred, A>::iterator it = m.begin();
      for (unsigned int i = 0; i < nSize; i++)
      {
          K key;
          Unserialize(is, key);
          it = m.insert(it, key);
      }
  }
  
  
  
  /**
   * unique_ptr
   */
  template<typename Stream, typename T> void
  Serialize(Stream& os, const std::unique_ptr<const T>& p)
  {
      Serialize(os, *p);
  }
  
  template<typename Stream, typename T>
  void Unserialize(Stream& is, std::unique_ptr<const T>& p)
  {
      p.reset(new T(deserialize, is));
  }
  
  
  
  /**
   * shared_ptr
   */
  template<typename Stream, typename T> void
  Serialize(Stream& os, const std::shared_ptr<const T>& p)
  {
      Serialize(os, *p);
  }
  
  template<typename Stream, typename T>
  void Unserialize(Stream& is, std::shared_ptr<const T>& p)
  {
      p = std::make_shared<const T>(deserialize, is);
  }
  
  
  
  /**
   * Support for ADD_SERIALIZE_METHODS and READWRITE macro
   */
  struct CSerActionSerialize
  {
      constexpr bool ForRead() const { return false; }
  };
  struct CSerActionUnserialize
  {
      constexpr bool ForRead() const { return true; }
  };
  
  
  
  
  
  
  
  
  /* ::GetSerializeSize implementations
   *
   * Computing the serialized size of objects is done through a special stream
   * object of type CSizeComputer, which only records the number of bytes written
   * to it.
   *
   * If your Serialize or SerializationOp method has non-trivial overhead for
   * serialization, it may be worthwhile to implement a specialized version for
   * CSizeComputer, which uses the s.seek() method to record bytes that would
   * be written instead.
   */
  class CSizeComputer
  {
  protected:
      size_t nSize;
  
      const int nVersion;
  public:
      explicit CSizeComputer(int nVersionIn) : nSize(0), nVersion(nVersionIn) {}
  
      void write(const char *psz, size_t _nSize)
      {
          this->nSize += _nSize;
      }
  
      /** Pretend _nSize bytes are written, without specifying them. */
      void seek(size_t _nSize)
      {
          this->nSize += _nSize;
      }
  
      template<typename T>
      CSizeComputer& operator<<(const T& obj)
      {
          ::Serialize(*this, obj);
          return (*this);
      }
  
      size_t size() const {
          return nSize;
      }
  
      int GetVersion() const { return nVersion; }
  };
  
  template<typename Stream>
  void SerializeMany(Stream& s)
  {
  }
  
  template<typename Stream, typename Arg, typename... Args>
  void SerializeMany(Stream& s, const Arg& arg, const Args&... args)
  {
      ::Serialize(s, arg);
      ::SerializeMany(s, args...);
  }
  
  template<typename Stream>
  inline void UnserializeMany(Stream& s)
  {
  }
  
  template<typename Stream, typename Arg, typename... Args>
  inline void UnserializeMany(Stream& s, Arg&& arg, Args&&... args)
  {
      ::Unserialize(s, arg);
      ::UnserializeMany(s, args...);
  }
  
  template<typename Stream, typename... Args>
  inline void SerReadWriteMany(Stream& s, CSerActionSerialize ser_action, const Args&... args)
  {
      ::SerializeMany(s, args...);
  }
  
  template<typename Stream, typename... Args>
  inline void SerReadWriteMany(Stream& s, CSerActionUnserialize ser_action, Args&&... args)
  {
      ::UnserializeMany(s, args...);
  }
  
  template<typename I>
  inline void WriteVarInt(CSizeComputer &s, I n)
  {
      s.seek(GetSizeOfVarInt<I>(n));
  }
  
  inline void WriteCompactSize(CSizeComputer &s, uint64_t nSize)
  {
      s.seek(GetSizeOfCompactSize(nSize));
  }
  
  template <typename T>
  size_t GetSerializeSize(const T& t, int nVersion = 0)
  {
      return (CSizeComputer(nVersion) << t).size();
  }
  
  template <typename... T>
  size_t GetSerializeSizeMany(int nVersion, const T&... t)
  {
      CSizeComputer sc(nVersion);
      SerializeMany(sc, t...);
      return sc.size();
  }
  
  #endif // BITCOIN_SERIALIZE_H
  