// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2022 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 #include // IWYU pragma: keep #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** * The maximum size of a serialized object in bytes or number of elements * (for eg vectors) when the size is encoded as CompactSize. */ static constexpr uint64_t MAX_SIZE = 0x02000000; /** Maximum amount of memory (in bytes) to allocate at once when deserializing vectors. */ static const unsigned int MAX_VECTOR_ALLOCATE = 5000000; /** * Dummy data type to identify deserializing constructors. * * By convention, a constructor of a type T with signature * * template 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 {}; /* * Lowest-level serialization and conversion. */ template inline void ser_writedata8(Stream &s, uint8_t obj) { s.write(AsBytes(Span{&obj, 1})); } template inline void ser_writedata16(Stream &s, uint16_t obj) { obj = htole16_internal(obj); s.write(AsBytes(Span{&obj, 1})); } template inline void ser_writedata16be(Stream &s, uint16_t obj) { obj = htobe16_internal(obj); s.write(AsBytes(Span{&obj, 1})); } template inline void ser_writedata32(Stream &s, uint32_t obj) { obj = htole32_internal(obj); s.write(AsBytes(Span{&obj, 1})); } template inline void ser_writedata32be(Stream &s, uint32_t obj) { obj = htobe32_internal(obj); s.write(AsBytes(Span{&obj, 1})); } template inline void ser_writedata64(Stream &s, uint64_t obj) { obj = htole64_internal(obj); s.write(AsBytes(Span{&obj, 1})); } template inline uint8_t ser_readdata8(Stream &s) { uint8_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return obj; } template inline uint16_t ser_readdata16(Stream &s) { uint16_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return le16toh_internal(obj); } template inline uint16_t ser_readdata16be(Stream &s) { uint16_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return be16toh_internal(obj); } template inline uint32_t ser_readdata32(Stream &s) { uint32_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return le32toh_internal(obj); } template inline uint32_t ser_readdata32be(Stream &s) { uint32_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return be32toh_internal(obj); } template inline uint64_t ser_readdata64(Stream &s) { uint64_t obj; s.read(AsWritableBytes(Span{&obj, 1})); return le64toh_internal(obj); } class SizeComputer; /** * Convert any argument to a reference to X, maintaining constness. * * This can be used in serialization code to invoke a base class's * serialization routines. * * Example use: * class Base { ... }; * class Child : public Base { * int m_data; * public: * SERIALIZE_METHODS(Child, obj) { * READWRITE(AsBase(obj), obj.m_data); * } * }; * * static_cast cannot easily be used here, as the type of Obj will be const Child& * during serialization and Child& during deserialization. AsBase will convert to * const Base& and Base& appropriately. */ template Out& AsBase(In& x) { static_assert(std::is_base_of_v); return x; } template const Out& AsBase(const In& x) { static_assert(std::is_base_of_v); return x; } #define READWRITE(...) (ser_action.SerReadWriteMany(s, __VA_ARGS__)) #define SER_READ(obj, code) ser_action.SerRead(s, obj, [&](Stream& s, typename std::remove_const::type& obj) { code; }) #define SER_WRITE(obj, code) ser_action.SerWrite(s, obj, [&](Stream& s, const Type& obj) { code; }) /** * Implement the Ser and Unser methods needed for implementing a formatter (see Using below). * * Both Ser and Unser are delegated to a single static method SerializationOps, which is polymorphic * in the serialized/deserialized type (allowing it to be const when serializing, and non-const when * deserializing). * * Example use: * struct FooFormatter { * FORMATTER_METHODS(Class, obj) { READWRITE(obj.val1, VARINT(obj.val2)); } * } * would define a class FooFormatter that defines a serialization of Class objects consisting * of serializing its val1 member using the default serialization, and its val2 member using * VARINT serialization. That FooFormatter can then be used in statements like * READWRITE(Using(obj.bla)). */ #define FORMATTER_METHODS(cls, obj) \ template \ static void Ser(Stream& s, const cls& obj) { SerializationOps(obj, s, ActionSerialize{}); } \ template \ static void Unser(Stream& s, cls& obj) { SerializationOps(obj, s, ActionUnserialize{}); } \ template \ static void SerializationOps(Type& obj, Stream& s, Operation ser_action) /** * Formatter methods can retrieve parameters attached to a stream using the * SER_PARAMS(type) macro as long as the stream is created directly or * indirectly with a parameter of that type. This permits making serialization * depend on run-time context in a type-safe way. * * Example use: * struct BarParameter { bool fancy; ... }; * struct Bar { ... }; * struct FooFormatter { * FORMATTER_METHODS(Bar, obj) { * auto& param = SER_PARAMS(BarParameter); * if (param.fancy) { * READWRITE(VARINT(obj.value)); * } else { * READWRITE(obj.value); * } * } * }; * which would then be invoked as * READWRITE(BarParameter{...}(Using(obj.foo))) * * parameter(obj) can be invoked anywhere in the call stack; it is * passed down recursively into all serialization code, until another * serialization parameter overrides it. * * Parameters will be implicitly converted where appropriate. This means that * "parent" serialization code can use a parameter that derives from, or is * convertible to, a "child" formatter's parameter type. * * Compilation will fail in any context where serialization is invoked but * no parameter of a type convertible to BarParameter is provided. */ #define SER_PARAMS(type) (s.template GetParams()) #define BASE_SERIALIZE_METHODS(cls) \ template \ void Serialize(Stream& s) const \ { \ static_assert(std::is_same::value, "Serialize type mismatch"); \ Ser(s, *this); \ } \ template \ void Unserialize(Stream& s) \ { \ static_assert(std::is_same::value, "Unserialize type mismatch"); \ Unser(s, *this); \ } /** * Implement the Serialize and Unserialize methods by delegating to a single templated * static method that takes the to-be-(de)serialized object as a parameter. This approach * has the advantage that the constness of the object becomes a template parameter, and * thus allows a single implementation that sees the object as const for serializing * and non-const for deserializing, without casts. */ #define SERIALIZE_METHODS(cls, obj) \ BASE_SERIALIZE_METHODS(cls) \ FORMATTER_METHODS(cls, obj) // Templates for serializing to anything that looks like a stream, // i.e. anything that supports .read(Span) and .write(Span) // // clang-format off // Typically int8_t and char are distinct types, but some systems may define int8_t // in terms of char. Forbid serialization of char in the typical case, but allow it if // it's the only way to describe an int8_t. template concept CharNotInt8 = std::same_as && !std::same_as; template void Serialize(Stream&, V) = delete; // char serialization forbidden. Use uint8_t or int8_t template void Serialize(Stream& s, std::byte a) { ser_writedata8(s, uint8_t(a)); } template inline void Serialize(Stream& s, int8_t a ) { ser_writedata8(s, a); } template inline void Serialize(Stream& s, uint8_t a ) { ser_writedata8(s, a); } template inline void Serialize(Stream& s, int16_t a ) { ser_writedata16(s, a); } template inline void Serialize(Stream& s, uint16_t a) { ser_writedata16(s, a); } template inline void Serialize(Stream& s, int32_t a ) { ser_writedata32(s, a); } template inline void Serialize(Stream& s, uint32_t a) { ser_writedata32(s, a); } template inline void Serialize(Stream& s, int64_t a ) { ser_writedata64(s, a); } template inline void Serialize(Stream& s, uint64_t a) { ser_writedata64(s, a); } template void Serialize(Stream& s, const B (&a)[N]) { s.write(MakeByteSpan(a)); } template void Serialize(Stream& s, const std::array& a) { s.write(MakeByteSpan(a)); } template void Serialize(Stream& s, Span span) { s.write(AsBytes(span)); } template void Unserialize(Stream&, V) = delete; // char serialization forbidden. Use uint8_t or int8_t template void Unserialize(Stream& s, std::byte& a) { a = std::byte{ser_readdata8(s)}; } template inline void Unserialize(Stream& s, int8_t& a ) { a = ser_readdata8(s); } template inline void Unserialize(Stream& s, uint8_t& a ) { a = ser_readdata8(s); } template inline void Unserialize(Stream& s, int16_t& a ) { a = ser_readdata16(s); } template inline void Unserialize(Stream& s, uint16_t& a) { a = ser_readdata16(s); } template inline void Unserialize(Stream& s, int32_t& a ) { a = ser_readdata32(s); } template inline void Unserialize(Stream& s, uint32_t& a) { a = ser_readdata32(s); } template inline void Unserialize(Stream& s, int64_t& a ) { a = ser_readdata64(s); } template inline void Unserialize(Stream& s, uint64_t& a) { a = ser_readdata64(s); } template void Unserialize(Stream& s, B (&a)[N]) { s.read(MakeWritableByteSpan(a)); } template void Unserialize(Stream& s, std::array& a) { s.read(MakeWritableByteSpan(a)); } template void Unserialize(Stream& s, Span span) { s.read(AsWritableBytes(span)); } template inline void Serialize(Stream& s, bool a) { uint8_t f = a; ser_writedata8(s, f); } template inline void Unserialize(Stream& s, bool& a) { uint8_t f = ser_readdata8(s); a = f; } // clang-format on /** * 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) */ constexpr inline unsigned int GetSizeOfCompactSize(uint64_t nSize) { if (nSize < 253) return sizeof(unsigned char); else if (nSize <= std::numeric_limits::max()) return sizeof(unsigned char) + sizeof(uint16_t); else if (nSize <= std::numeric_limits::max()) return sizeof(unsigned char) + sizeof(unsigned int); else return sizeof(unsigned char) + sizeof(uint64_t); } inline void WriteCompactSize(SizeComputer& os, uint64_t nSize); template void WriteCompactSize(Stream& os, uint64_t nSize) { if (nSize < 253) { ser_writedata8(os, nSize); } else if (nSize <= std::numeric_limits::max()) { ser_writedata8(os, 253); ser_writedata16(os, nSize); } else if (nSize <= std::numeric_limits::max()) { ser_writedata8(os, 254); ser_writedata32(os, nSize); } else { ser_writedata8(os, 255); ser_writedata64(os, nSize); } return; } /** * Decode a CompactSize-encoded variable-length integer. * * As these are primarily used to encode the size of vector-like serializations, by default a range * check is performed. When used as a generic number encoding, range_check should be set to false. */ template uint64_t ReadCompactSize(Stream& is, bool range_check = true) { 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 (range_check && nSizeRet > 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 struct CheckVarIntMode { constexpr CheckVarIntMode() { static_assert(Mode != VarIntMode::DEFAULT || std::is_unsigned::value, "Unsigned type required with mode DEFAULT."); static_assert(Mode != VarIntMode::NONNEGATIVE_SIGNED || std::is_signed::value, "Signed type required with mode NONNEGATIVE_SIGNED."); } }; template inline unsigned int GetSizeOfVarInt(I n) { CheckVarIntMode(); int nRet = 0; while(true) { nRet++; if (n <= 0x7F) break; n = (n >> 7) - 1; } return nRet; } template inline void WriteVarInt(SizeComputer& os, I n); template void WriteVarInt(Stream& os, I n) { CheckVarIntMode(); 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 I ReadVarInt(Stream& is) { CheckVarIntMode(); I n = 0; while(true) { unsigned char chData = ser_readdata8(is); if (n > (std::numeric_limits::max() >> 7)) { throw std::ios_base::failure("ReadVarInt(): size too large"); } n = (n << 7) | (chData & 0x7F); if (chData & 0x80) { if (n == std::numeric_limits::max()) { throw std::ios_base::failure("ReadVarInt(): size too large"); } n++; } else { return n; } } } /** Simple wrapper class to serialize objects using a formatter; used by Using(). */ template class Wrapper { static_assert(std::is_lvalue_reference::value, "Wrapper needs an lvalue reference type T"); protected: T m_object; public: explicit Wrapper(T obj) : m_object(obj) {} template void Serialize(Stream &s) const { Formatter().Ser(s, m_object); } template void Unserialize(Stream &s) { Formatter().Unser(s, m_object); } }; /** Cause serialization/deserialization of an object to be done using a specified formatter class. * * To use this, you need a class Formatter that has public functions Ser(stream, const object&) for * serialization, and Unser(stream, object&) for deserialization. Serialization routines (inside * READWRITE, or directly with << and >> operators), can then use Using(object). * * This works by constructing a Wrapper-wrapped version of object, where T is * const during serialization, and non-const during deserialization, which maintains const * correctness. */ template static inline Wrapper Using(T&& t) { return Wrapper(t); } #define VARINT_MODE(obj, mode) Using>(obj) #define VARINT(obj) Using>(obj) #define COMPACTSIZE(obj) Using>(obj) #define LIMITED_STRING(obj,n) Using>(obj) /** Serialization wrapper class for integers in VarInt format. */ template struct VarIntFormatter { template void Ser(Stream &s, I v) { WriteVarInt::type>(s, v); } template void Unser(Stream& s, I& v) { v = ReadVarInt::type>(s); } }; /** Serialization wrapper class for custom integers and enums. * * It permits specifying the serialized size (1 to 8 bytes) and endianness. * * Use the big endian mode for values 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. */ template struct CustomUintFormatter { static_assert(Bytes > 0 && Bytes <= 8, "CustomUintFormatter Bytes out of range"); static constexpr uint64_t MAX = 0xffffffffffffffff >> (8 * (8 - Bytes)); template void Ser(Stream& s, I v) { if (v < 0 || v > MAX) throw std::ios_base::failure("CustomUintFormatter value out of range"); if (BigEndian) { uint64_t raw = htobe64_internal(v); s.write(AsBytes(Span{&raw, 1}).last(Bytes)); } else { uint64_t raw = htole64_internal(v); s.write(AsBytes(Span{&raw, 1}).first(Bytes)); } } template void Unser(Stream& s, I& v) { using U = typename std::conditional::value, std::underlying_type, std::common_type>::type::type; static_assert(std::numeric_limits::max() >= MAX && std::numeric_limits::min() <= 0, "Assigned type too small"); uint64_t raw = 0; if (BigEndian) { s.read(AsWritableBytes(Span{&raw, 1}).last(Bytes)); v = static_cast(be64toh_internal(raw)); } else { s.read(AsWritableBytes(Span{&raw, 1}).first(Bytes)); v = static_cast(le64toh_internal(raw)); } } }; template using BigEndianFormatter = CustomUintFormatter; /** Formatter for integers in CompactSize format. */ template struct CompactSizeFormatter { template void Unser(Stream& s, I& v) { uint64_t n = ReadCompactSize(s, RangeCheck); if (n < std::numeric_limits::min() || n > std::numeric_limits::max()) { throw std::ios_base::failure("CompactSize exceeds limit of type"); } v = n; } template void Ser(Stream& s, I v) { static_assert(std::is_unsigned::value, "CompactSize only supported for unsigned integers"); static_assert(std::numeric_limits::max() <= std::numeric_limits::max(), "CompactSize only supports 64-bit integers and below"); WriteCompactSize(s, v); } }; template struct ChronoFormatter { template void Unser(Stream& s, Tp& tp) { U u; s >> u; // Lossy deserialization does not make sense, so force Wnarrowing tp = Tp{typename Tp::duration{typename Tp::duration::rep{u}}}; } template void Ser(Stream& s, Tp tp) { if constexpr (LOSSY) { s << U(tp.time_since_epoch().count()); } else { s << U{tp.time_since_epoch().count()}; } } }; template using LossyChronoFormatter = ChronoFormatter; class CompactSizeWriter { protected: uint64_t n; public: explicit CompactSizeWriter(uint64_t n_in) : n(n_in) { } template void Serialize(Stream &s) const { WriteCompactSize(s, n); } }; template struct LimitedStringFormatter { template void Unser(Stream& s, std::string& v) { size_t size = ReadCompactSize(s); if (size > Limit) { throw std::ios_base::failure("String length limit exceeded"); } v.resize(size); if (size != 0) s.read(MakeWritableByteSpan(v)); } template void Ser(Stream& s, const std::string& v) { s << v; } }; /** Formatter to serialize/deserialize vector elements using another formatter * * Example: * struct X { * std::vector v; * SERIALIZE_METHODS(X, obj) { READWRITE(Using>(obj.v)); } * }; * will define a struct that contains a vector of uint64_t, which is serialized * as a vector of VarInt-encoded integers. * * V is not required to be an std::vector type. It works for any class that * exposes a value_type, size, reserve, emplace_back, back, and const iterators. */ template struct VectorFormatter { template 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 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()); } } }; }; /** * Forward declarations */ /** * string */ template void Serialize(Stream& os, const std::basic_string& str); template void Unserialize(Stream& is, std::basic_string& str); /** * prevector */ template inline void Serialize(Stream& os, const prevector& v); template inline void Unserialize(Stream& is, prevector& v); /** * vector */ template inline void Serialize(Stream& os, const std::vector& v); template inline void Unserialize(Stream& is, std::vector& v); /** * pair */ template void Serialize(Stream& os, const std::pair& item); template void Unserialize(Stream& is, std::pair& item); /** * map */ template void Serialize(Stream& os, const std::map& m); template void Unserialize(Stream& is, std::map& m); /** * set */ template void Serialize(Stream& os, const std::set& m); template void Unserialize(Stream& is, std::set& m); /** * shared_ptr */ template void Serialize(Stream& os, const std::shared_ptr& p); template void Unserialize(Stream& os, std::shared_ptr& p); /** * unique_ptr */ template void Serialize(Stream& os, const std::unique_ptr& p); template void Unserialize(Stream& os, std::unique_ptr& p); /** * If none of the specialized versions above matched, default to calling member function. */ template concept Serializable = requires(T a, Stream s) { a.Serialize(s); }; template requires Serializable void Serialize(Stream& os, const T& a) { a.Serialize(os); } template concept Unserializable = requires(T a, Stream s) { a.Unserialize(s); }; template requires Unserializable void Unserialize(Stream& is, T&& a) { a.Unserialize(is); } /** Default formatter. Serializes objects as themselves. * * The vector/prevector serialization code passes this to VectorFormatter * to enable reusing that logic. It shouldn't be needed elsewhere. */ struct DefaultFormatter { template static void Ser(Stream& s, const T& t) { Serialize(s, t); } template static void Unser(Stream& s, T& t) { Unserialize(s, t); } }; /** * string */ template void Serialize(Stream& os, const std::basic_string& str) { WriteCompactSize(os, str.size()); if (!str.empty()) os.write(MakeByteSpan(str)); } template void Unserialize(Stream& is, std::basic_string& str) { unsigned int nSize = ReadCompactSize(is); str.resize(nSize); if (nSize != 0) is.read(MakeWritableByteSpan(str)); } /** * prevector */ template void Serialize(Stream& os, const prevector& v) { if constexpr (BasicByte) { // Use optimized version for unformatted basic bytes WriteCompactSize(os, v.size()); if (!v.empty()) os.write(MakeByteSpan(v)); } else { Serialize(os, Using>(v)); } } template void Unserialize(Stream& is, prevector& v) { if constexpr (BasicByte) { // Use optimized version for unformatted basic bytes // 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(AsWritableBytes(Span{&v[i], blk})); i += blk; } } else { Unserialize(is, Using>(v)); } } /** * vector */ template void Serialize(Stream& os, const std::vector& v) { if constexpr (BasicByte) { // Use optimized version for unformatted basic bytes WriteCompactSize(os, v.size()); if (!v.empty()) os.write(MakeByteSpan(v)); } else if constexpr (std::is_same_v) { // A special case for std::vector, as dereferencing // std::vector::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); } } else { Serialize(os, Using>(v)); } } template void Unserialize(Stream& is, std::vector& v) { if constexpr (BasicByte) { // Use optimized version for unformatted basic bytes // 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(AsWritableBytes(Span{&v[i], blk})); i += blk; } } else { Unserialize(is, Using>(v)); } } /** * pair */ template void Serialize(Stream& os, const std::pair& item) { Serialize(os, item.first); Serialize(os, item.second); } template void Unserialize(Stream& is, std::pair& item) { Unserialize(is, item.first); Unserialize(is, item.second); } /** * map */ template void Serialize(Stream& os, const std::map& m) { WriteCompactSize(os, m.size()); for (const auto& entry : m) Serialize(os, entry); } template void Unserialize(Stream& is, std::map& m) { m.clear(); unsigned int nSize = ReadCompactSize(is); typename std::map::iterator mi = m.begin(); for (unsigned int i = 0; i < nSize; i++) { std::pair item; Unserialize(is, item); mi = m.insert(mi, item); } } /** * set */ template void Serialize(Stream& os, const std::set& m) { WriteCompactSize(os, m.size()); for (typename std::set::const_iterator it = m.begin(); it != m.end(); ++it) Serialize(os, (*it)); } template void Unserialize(Stream& is, std::set& m) { m.clear(); unsigned int nSize = ReadCompactSize(is); typename std::set::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 void Serialize(Stream& os, const std::unique_ptr& p) { Serialize(os, *p); } template void Unserialize(Stream& is, std::unique_ptr& p) { p.reset(new T(deserialize, is)); } /** * shared_ptr */ template void Serialize(Stream& os, const std::shared_ptr& p) { Serialize(os, *p); } template void Unserialize(Stream& is, std::shared_ptr& p) { p = std::make_shared(deserialize, is); } /** * Support for (un)serializing many things at once */ template void SerializeMany(Stream& s, const Args&... args) { (::Serialize(s, args), ...); } template inline void UnserializeMany(Stream& s, Args&&... args) { (::Unserialize(s, args), ...); } /** * Support for all macros providing or using the ser_action parameter of the SerializationOps method. */ struct ActionSerialize { static constexpr bool ForRead() { return false; } template static void SerReadWriteMany(Stream& s, const Args&... args) { ::SerializeMany(s, args...); } template static void SerRead(Stream& s, Type&&, Fn&&) { } template static void SerWrite(Stream& s, Type&& obj, Fn&& fn) { fn(s, std::forward(obj)); } }; struct ActionUnserialize { static constexpr bool ForRead() { return true; } template static void SerReadWriteMany(Stream& s, Args&&... args) { ::UnserializeMany(s, args...); } template static void SerRead(Stream& s, Type&& obj, Fn&& fn) { fn(s, std::forward(obj)); } template static void SerWrite(Stream& s, Type&&, Fn&&) { } }; /* ::GetSerializeSize implementations * * Computing the serialized size of objects is done through a special stream * object of type SizeComputer, 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 * SizeComputer, which uses the s.seek() method to record bytes that would * be written instead. */ class SizeComputer { protected: size_t nSize{0}; public: SizeComputer() = default; void write(Span src) { this->nSize += src.size(); } /** Pretend _nSize bytes are written, without specifying them. */ void seek(size_t _nSize) { this->nSize += _nSize; } template SizeComputer& operator<<(const T& obj) { ::Serialize(*this, obj); return (*this); } size_t size() const { return nSize; } }; template inline void WriteVarInt(SizeComputer &s, I n) { s.seek(GetSizeOfVarInt(n)); } inline void WriteCompactSize(SizeComputer &s, uint64_t nSize) { s.seek(GetSizeOfCompactSize(nSize)); } template size_t GetSerializeSize(const T& t) { return (SizeComputer() << t).size(); } //! Check if type contains a stream by seeing if has a GetStream() method. template concept ContainsStream = requires(T t) { t.GetStream(); }; /** Wrapper that overrides the GetParams() function of a stream. */ template class ParamsStream { const Params& m_params; // If ParamsStream constructor is passed an lvalue argument, Substream will // be a reference type, and m_substream will reference that argument. // Otherwise m_substream will be a substream instance and move from the // argument. Letting ParamsStream contain a substream instance instead of // just a reference is useful to make the ParamsStream object self contained // and let it do cleanup when destroyed, for example by closing files if // SubStream is a file stream. SubStream m_substream; public: ParamsStream(SubStream&& substream, const Params& params LIFETIMEBOUND) : m_params{params}, m_substream{std::forward(substream)} {} template ParamsStream(NestedSubstream&& s, const Params1& params1 LIFETIMEBOUND, const Params2& params2 LIFETIMEBOUND, const NestedParams&... params LIFETIMEBOUND) : ParamsStream{::ParamsStream{std::forward(s), params2, params...}, params1} {} template ParamsStream& operator<<(const U& obj) { ::Serialize(*this, obj); return *this; } template ParamsStream& operator>>(U&& obj) { ::Unserialize(*this, obj); return *this; } void write(Span src) { GetStream().write(src); } void read(Span dst) { GetStream().read(dst); } void ignore(size_t num) { GetStream().ignore(num); } bool eof() const { return GetStream().eof(); } size_t size() const { return GetStream().size(); } //! Get reference to stream parameters. template const auto& GetParams() const { if constexpr (std::is_convertible_v) { return m_params; } else { return m_substream.template GetParams

(); } } //! Get reference to underlying stream. auto& GetStream() { if constexpr (ContainsStream) { return m_substream.GetStream(); } else { return m_substream; } } const auto& GetStream() const { if constexpr (ContainsStream) { return m_substream.GetStream(); } else { return m_substream; } } }; /** * Explicit template deduction guide is required for single-parameter * constructor so Substream&& is treated as a forwarding reference, and * SubStream is deduced as reference type for lvalue arguments. */ template ParamsStream(Substream&&, const Params&) -> ParamsStream; /** * Template deduction guide for multiple params arguments that creates a nested * ParamsStream. */ template ParamsStream(Substream&& s, const Params1& params1, const Params2& params2, const Params&... params) -> ParamsStream(s), params2, params...}), Params1>; /** Wrapper that serializes objects with the specified parameters. */ template class ParamsWrapper { const Params& m_params; T& m_object; public: explicit ParamsWrapper(const Params& params, T& obj) : m_params{params}, m_object{obj} {} template void Serialize(Stream& s) const { ParamsStream ss{s, m_params}; ::Serialize(ss, m_object); } template void Unserialize(Stream& s) { ParamsStream ss{s, m_params}; ::Unserialize(ss, m_object); } }; /** * Helper macro for SerParams structs * * Allows you define SerParams instances and then apply them directly * to an object via function call syntax, eg: * * constexpr SerParams FOO{....}; * ss << FOO(obj); */ #define SER_PARAMS_OPFUNC \ /** \ * Return a wrapper around t that (de)serializes it with specified parameter params. \ * \ * See SER_PARAMS for more information on serialization parameters. \ */ \ template \ auto operator()(T&& t) const \ { \ return ParamsWrapper{*this, t}; \ } #endif // BITCOIN_SERIALIZE_H