serialize.h

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// 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_SERIALIZE_H
#define BITCOIN_SERIALIZE_H

#include <compat/endian.h>
#include <prevector.h>
#include <span.h>

#include <algorithm>
#include <array>
#include <cstdint>
#include <cstring>
#include <ios>
#include <limits>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>

static const uint64_t MAX_SIZE = 0x02000000;

static const unsigned int MAX_VECTOR_ALLOCATE = 5000000;

struct deserialize_type {};
constexpr deserialize_type deserialize{};

template <typename T> inline T &REF(const T &val) {
    return const_cast<T &>(val);
}

template <typename T> inline T *NCONST_PTR(const T *val) {
    return const_cast<T *>(val);
}

inline char *CharCast(char *c) {
    return c;
}
inline char *CharCast(uint8_t *c) {
    return (char *)c;
}
inline const char *CharCast(const char *c) {
    return c;
}
inline const char *CharCast(const uint8_t *c) {
    return (const char *)c;
}

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) {
    uint64_t tmp;
    std::memcpy(&tmp, &x, sizeof(x));
    static_assert(sizeof(tmp) == sizeof(x),
                  "double and uint64_t assumed to have the same size");
    return tmp;
}
inline uint32_t ser_float_to_uint32(float x) {
    uint32_t tmp;
    std::memcpy(&tmp, &x, sizeof(x));
    static_assert(sizeof(tmp) == sizeof(x),
                  "float and uint32_t assumed to have the same size");
    return tmp;
}
inline double ser_uint64_to_double(uint64_t y) {
    double tmp;
    std::memcpy(&tmp, &y, sizeof(y));
    static_assert(sizeof(tmp) == sizeof(y),
                  "double and uint64_t assumed to have the same size");
    return tmp;
}
inline float ser_uint32_to_float(uint32_t y) {
    float tmp;
    std::memcpy(&tmp, &y, sizeof(y));
    static_assert(sizeof(tmp) == sizeof(y),
                  "float and uint32_t assumed to have the same size");
    return tmp;
}

//
// 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),
};

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)))

#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());                           \
    }

#define FORMATTER_METHODS(cls, obj)                                            \
    template <typename Stream> static void Ser(Stream &s, const cls &obj) {    \
        SerializationOps(obj, s, CSerActionSerialize());                       \
    }                                                                          \
    template <typename Stream> static void Unser(Stream &s, cls &obj) {        \
        SerializationOps(obj, s, CSerActionUnserialize());                     \
    }                                                                          \
    template <typename Stream, typename Type, typename Operation>              \
    static inline void SerializationOps(Type &obj, Stream &s,                  \
                                        Operation ser_action)

#define SERIALIZE_METHODS(cls, obj)                                            \
    template <typename Stream> void Serialize(Stream &s) const {               \
        static_assert(std::is_same<const cls &, decltype(*this)>::value,       \
                      "Serialize type mismatch");                              \
        Ser(s, *this);                                                         \
    }                                                                          \
    template <typename Stream> void Unserialize(Stream &s) {                   \
        static_assert(std::is_same<cls &, decltype(*this)>::value,             \
                      "Unserialize type mismatch");                            \
        Unser(s, *this);                                                       \
    }                                                                          \
    FORMATTER_METHODS(cls, obj)

#ifndef CHAR_EQUALS_INT8
// TODO Get rid of bare char
template <typename Stream> inline void Serialize(Stream &s, char a) {
    ser_writedata8(s, a);
}
#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, size_t N>
inline void Serialize(Stream &s, const int8_t (&a)[N]) {
    s.write(a, N);
}
template <typename Stream, size_t N>
inline void Serialize(Stream &s, const uint8_t (&a)[N]) {
    s.write(CharCast(a), N);
}
template <typename Stream, size_t N>
inline void Serialize(Stream &s, const std::array<int8_t, N> &a) {
    s.write(a.data(), N);
}
template <typename Stream, size_t N>
inline void Serialize(Stream &s, const std::array<uint8_t, N> &a) {
    s.write(CharCast(a.data()), N);
}
#ifndef CHAR_EQUALS_INT8
// TODO Get rid of bare char
template <typename Stream> inline void Unserialize(Stream &s, char &a) {
    a = ser_readdata8(s);
}
template <typename Stream, size_t N>
inline void Serialize(Stream &s, const char (&a)[N]) {
    s.write(a, N);
}
template <typename Stream, size_t N>
inline void Serialize(Stream &s, const std::array<char, N> &a) {
    s.write(a.data(), N);
}
#endif
template <typename Stream>
inline void Serialize(Stream &s, const Span<const uint8_t> &span) {
    s.write(CharCast(span.data()), span.size());
}
template <typename Stream>
inline void Serialize(Stream &s, const Span<uint8_t> &span) {
    s.write(CharCast(span.data()), span.size());
}
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, size_t N>
inline void Unserialize(Stream &s, int8_t (&a)[N]) {
    s.read(a, N);
}
template <typename Stream, size_t N>
inline void Unserialize(Stream &s, uint8_t (&a)[N]) {
    s.read(CharCast(a), N);
}
template <typename Stream, size_t N>
inline void Unserialize(Stream &s, std::array<int8_t, N> &a) {
    s.read(a.data(), N);
}
template <typename Stream, size_t N>
inline void Unserialize(Stream &s, std::array<uint8_t, N> &a) {
    s.read(CharCast(a.data()), N);
}
#ifndef CHAR_EQUALS_INT8
template <typename Stream, size_t N>
inline void Unserialize(Stream &s, char (&a)[N]) {
    s.read(CharCast(a), N);
}
template <typename Stream, size_t N>
inline void Unserialize(Stream &s, std::array<char, N> &a) {
    s.read(CharCast(a.data()), N);
}
#endif

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;
}
template <typename Stream>
inline void Unserialize(Stream &s, Span<uint8_t> &span) {
    s.read(CharCast(span.data()), span.size());
}

inline uint32_t GetSizeOfCompactSize(uint64_t nSize) {
    if (nSize < 253) {
        return sizeof(uint8_t);
    }
    if (nSize <= std::numeric_limits<uint16_t>::max()) {
        return sizeof(uint8_t) + sizeof(uint16_t);
    }
    if (nSize <= std::numeric_limits<uint32_t>::max()) {
        return sizeof(uint8_t) + sizeof(uint32_t);
    }

    return sizeof(uint8_t) + 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<uint16_t>::max()) {
        ser_writedata8(os, 253);
        ser_writedata16(os, nSize);
    } else if (nSize <= std::numeric_limits<uint32_t>::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 > MAX_SIZE) {
        throw std::ios_base::failure("ReadCompactSize(): size too large");
    }
    return nSizeRet;
}

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) {
            return nRet;
        }
        n = (n >> 7) - 1;
    }
}

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>();
    uint8_t 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) {
        uint8_t 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) == 0) {
            return n;
        }
        if (n == std::numeric_limits<I>::max()) {
            throw std::ios_base::failure("ReadVarInt(): size too large");
        }
        n++;
    }
}

template <typename Formatter, typename T> class Wrapper {
    static_assert(std::is_lvalue_reference<T>::value,
                  "Wrapper needs an lvalue reference type T");

protected:
    T m_object;

public:
    explicit Wrapper(T obj) : m_object(obj) {}
    template <typename Stream> void Serialize(Stream &s) const {
        Formatter().Ser(s, m_object);
    }
    template <typename Stream> void Unserialize(Stream &s) {
        Formatter().Unser(s, m_object);
    }
};

template <typename Formatter, typename T>
static inline Wrapper<Formatter, T &> Using(T &&t) {
    return Wrapper<Formatter, T &>(t);
}

#define VARINT_MODE(obj, mode) Using<VarIntFormatter<mode>>(obj)
#define VARINT(obj) Using<VarIntFormatter<VarIntMode::DEFAULT>>(obj)
#define COMPACTSIZE(obj) Using<CompactSizeFormatter>(obj)
#define LIMITED_STRING(obj, n) LimitedString<n>(REF(obj))

template <VarIntMode Mode> struct VarIntFormatter {
    template <typename Stream, typename I> void Ser(Stream &s, I v) {
        WriteVarInt<Stream, Mode, typename std::remove_cv<I>::type>(s, v);
    }

    template <typename Stream, typename I> void Unser(Stream &s, I &v) {
        v = ReadVarInt<Stream, Mode, typename std::remove_cv<I>::type>(s);
    }
};

template <int Bytes> struct CustomUintFormatter {
    static_assert(Bytes > 0 && Bytes <= 8,
                  "CustomUintFormatter Bytes out of range");
    static constexpr uint64_t MAX = 0xffffffffffffffff >> (8 * (8 - Bytes));

    template <typename Stream, typename I> void Ser(Stream &s, I v) {
        if (v < 0 || v > MAX) {
            throw std::ios_base::failure(
                "CustomUintFormatter value out of range");
        }
        uint64_t raw = htole64(v);
        s.write((const char *)&raw, Bytes);
    }

    template <typename Stream, typename I> void Unser(Stream &s, I &v) {
        static_assert(std::numeric_limits<I>::max() >= MAX &&
                          std::numeric_limits<I>::min() <= 0,
                      "CustomUintFormatter type too small");
        uint64_t raw = 0;
        s.read((char *)&raw, Bytes);
        v = le64toh(raw);
    }
};

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);
    }
};

struct CompactSizeFormatter {
    template <typename Stream, typename I> void Unser(Stream &s, I &v) {
        uint64_t n = ReadCompactSize<Stream>(s);
        if (n < std::numeric_limits<I>::min() ||
            n > std::numeric_limits<I>::max()) {
            throw std::ios_base::failure("CompactSize exceeds limit of type");
        }
        v = n;
    }

    template <typename Stream, typename I> void Ser(Stream &s, I v) {
        static_assert(std::is_unsigned<I>::value,
                      "CompactSize only supported for unsigned integers");
        static_assert(std::numeric_limits<I>::max() <=
                          std::numeric_limits<uint64_t>::max(),
                      "CompactSize only supports 64-bit integers and below");

        WriteCompactSize<Stream>(s, v);
    }
};

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 <typename I> BigEndian<I> WrapBigEndian(I &n) {
    return BigEndian<I>(n);
}

template <class Formatter> struct VectorFormatter {
    template <typename Stream, typename V> void Ser(Stream &s, const V &v) {
        Formatter formatter;
        WriteCompactSize(s, v.size());
        for (const typename V::value_type &elem : v) {
            formatter.Ser(s, elem);
        }
    }

    template <typename Stream, typename V> void Unser(Stream &s, V &v) {
        Formatter formatter;
        v.clear();
        size_t size = ReadCompactSize(s);
        size_t allocated = 0;
        while (allocated < size) {
            // For DoS prevention, do not blindly allocate as much as the stream
            // claims to contain. Instead, allocate in 5MiB batches, so that an
            // attacker actually needs to provide X MiB of data to make us
            // allocate X+5 Mib.
            static_assert(sizeof(typename V::value_type) <= MAX_VECTOR_ALLOCATE,
                          "Vector element size too large");
            allocated =
                std::min(size, allocated + MAX_VECTOR_ALLOCATE /
                                               sizeof(typename V::value_type));
            v.reserve(allocated);
            while (v.size() < allocated) {
                v.emplace_back();
                formatter.Unser(s, v.back());
            }
        }
    };
};

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);

template <typename Stream, unsigned int N, typename T>
void Serialize_impl(Stream &os, const prevector<N, T> &v, const uint8_t &);
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 uint8_t &);
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);

template <typename Stream, typename T, typename A>
void Serialize_impl(Stream &os, const std::vector<T, A> &v, const uint8_t &);
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 uint8_t &);
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);

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);

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);

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);

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);

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);

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);
}

struct DefaultFormatter {
    template <typename Stream, typename T>
    static void Ser(Stream &s, const T &t) {
        Serialize(s, t);
    }

    template <typename Stream, typename T> static void Unser(Stream &s, T &t) {
        Unserialize(s, t);
    }
};

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) {
    size_t nSize = ReadCompactSize(is);
    str.resize(nSize);
    if (nSize != 0) {
        is.read((char *)str.data(), nSize * sizeof(C));
    }
}

template <typename Stream, unsigned int N, typename T>
void Serialize_impl(Stream &os, const prevector<N, T> &v, const uint8_t &) {
    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 &) {
    Serialize(os, Using<VectorFormatter<DefaultFormatter>>(v));
}

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 uint8_t &) {
    // Limit size per read so bogus size value won't cause out of memory
    v.clear();
    size_t nSize = ReadCompactSize(is);
    size_t i = 0;
    while (i < nSize) {
        size_t blk = std::min(nSize - i, size_t(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 &) {
    Unserialize(is, Using<VectorFormatter<DefaultFormatter>>(v));
}

template <typename Stream, unsigned int N, typename T>
inline void Unserialize(Stream &is, prevector<N, T> &v) {
    Unserialize_impl(is, v, T());
}

template <typename Stream, typename T, typename A>
void Serialize_impl(Stream &os, const std::vector<T, A> &v, const uint8_t &) {
    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 &) {
    Serialize(os, Using<VectorFormatter<DefaultFormatter>>(v));
}

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 uint8_t &) {
    // Limit size per read so bogus size value won't cause out of memory
    v.clear();
    size_t nSize = ReadCompactSize(is);
    size_t i = 0;
    while (i < nSize) {
        size_t blk = std::min(nSize - i, size_t(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 &) {
    Unserialize(is, Using<VectorFormatter<DefaultFormatter>>(v));
}

template <typename Stream, typename T, typename A>
inline void Unserialize(Stream &is, std::vector<T, A> &v) {
    Unserialize_impl(is, v, T());
}

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);
}

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();
    size_t nSize = ReadCompactSize(is);
    typename std::map<K, T, Pred, A>::iterator mi = m.begin();
    for (size_t i = 0; i < nSize; i++) {
        std::pair<K, T> item;
        Unserialize(is, item);
        mi = m.insert(mi, item);
    }
}

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 (const K &i : m) {
        Serialize(os, i);
    }
}

template <typename Stream, typename K, typename Pred, typename A>
void Unserialize(Stream &is, std::set<K, Pred, A> &m) {
    m.clear();
    size_t nSize = ReadCompactSize(is);
    typename std::set<K, Pred, A>::iterator it = m.begin();
    for (size_t i = 0; i < nSize; i++) {
        K key;
        Unserialize(is, key);
        it = m.insert(it, key);
    }
}

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));
}

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);
}

struct CSerActionSerialize {
    constexpr bool ForRead() const { return false; }
};
struct CSerActionUnserialize {
    constexpr bool ForRead() const { return true; }
};

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; }

    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