RLP.h

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/*
        This file is part of cpp-ethereum.

        cpp-ethereum is free software: you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version.

        cpp-ethereum is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once

#include <vector>
#include <array>
#include <exception>
#include <iostream>
#include <iomanip>
#include "vector_ref.h"
#include "Common.h"
#include "Exceptions.h"
#include "FixedHash.h"

namespace dev
{

class RLP;
using RLPs = std::vector<RLP>;

template <class _T> struct intTraits { static const unsigned maxSize = sizeof(_T); };
template <> struct intTraits<u160> { static const unsigned maxSize = 20; };
template <> struct intTraits<u256> { static const unsigned maxSize = 32; };
template <> struct intTraits<bigint> { static const unsigned maxSize = ~(unsigned)0; };

static const byte c_rlpMaxLengthBytes = 8;
static const byte c_rlpDataImmLenStart = 0x80;
static const byte c_rlpListStart = 0xc0;

static const byte c_rlpDataImmLenCount = c_rlpListStart - c_rlpDataImmLenStart - c_rlpMaxLengthBytes;
static const byte c_rlpDataIndLenZero = c_rlpDataImmLenStart + c_rlpDataImmLenCount - 1;
static const byte c_rlpListImmLenCount = 256 - c_rlpListStart - c_rlpMaxLengthBytes;
static const byte c_rlpListIndLenZero = c_rlpListStart + c_rlpListImmLenCount - 1;

template <class T> struct Converter { static T convert(RLP const&, int) { BOOST_THROW_EXCEPTION(BadCast()); } };

class RLP
{
public:
        enum
        {
                AllowNonCanon = 1,
                ThrowOnFail = 4,
                FailIfTooBig = 8,
                FailIfTooSmall = 16,
                Strict = ThrowOnFail | FailIfTooBig,
                VeryStrict = ThrowOnFail | FailIfTooBig | FailIfTooSmall,
                LaissezFaire = AllowNonCanon
        };

        using Strictness = int;

        RLP() {}

        explicit RLP(bytesConstRef _d, Strictness _s = VeryStrict);

        explicit RLP(bytes const& _d, Strictness _s = VeryStrict): RLP(&_d, _s) {}

        RLP(byte const* _b, unsigned _s, Strictness _st = VeryStrict): RLP(bytesConstRef(_b, _s), _st) {}

        explicit RLP(std::string const& _s, Strictness _st = VeryStrict): RLP(bytesConstRef((byte const*)_s.data(), _s.size()), _st) {}

        bytesConstRef data() const { return m_data; }

        explicit operator bool() const { return !isNull(); }

        bool isNull() const { return m_data.size() == 0; }

        bool isEmpty() const { return !isNull() && (m_data[0] == c_rlpDataImmLenStart || m_data[0] == c_rlpListStart); }

        bool isData() const { return !isNull() && m_data[0] < c_rlpListStart; }

        bool isList() const { return !isNull() && m_data[0] >= c_rlpListStart; }

        bool isInt() const;

        size_t itemCount() const { return isList() ? items() : 0; }
        size_t itemCountStrict() const { if (!isList()) BOOST_THROW_EXCEPTION(BadCast()); return items(); }

        size_t size() const { return isData() ? length() : 0; }
        size_t sizeStrict() const { if (!isData()) BOOST_THROW_EXCEPTION(BadCast()); return length(); }

        bool operator==(char const* _s) const { return isData() && toString() == _s; }
        bool operator!=(char const* _s) const { return isData() && toString() != _s; }
        bool operator==(std::string const& _s) const { return isData() && toString() == _s; }
        bool operator!=(std::string const& _s) const { return isData() && toString() != _s; }
        template <unsigned _N> bool operator==(FixedHash<_N> const& _h) const { return isData() && toHash<_N>() == _h; }
        template <unsigned _N> bool operator!=(FixedHash<_N> const& _s) const { return isData() && toHash<_N>() != _s; }
        bool operator==(unsigned const& _i) const { return isInt() && toInt<unsigned>() == _i; }
        bool operator!=(unsigned const& _i) const { return isInt() && toInt<unsigned>() != _i; }
        bool operator==(u256 const& _i) const { return isInt() && toInt<u256>() == _i; }
        bool operator!=(u256 const& _i) const { return isInt() && toInt<u256>() != _i; }
        bool operator==(bigint const& _i) const { return isInt() && toInt<bigint>() == _i; }
        bool operator!=(bigint const& _i) const { return isInt() && toInt<bigint>() != _i; }

        RLP operator[](size_t _i) const;

        using element_type = RLP;

        class iterator
        {
                friend class RLP;

        public:
                using value_type = RLP;
                using element_type = RLP;

                iterator& operator++();
                iterator operator++(int) { auto ret = *this; operator++(); return ret; }
                RLP operator*() const { return RLP(m_currentItem); }
                bool operator==(iterator const& _cmp) const { return m_currentItem == _cmp.m_currentItem; }
                bool operator!=(iterator const& _cmp) const { return !operator==(_cmp); }

        private:
                iterator() {}
                iterator(RLP const& _parent, bool _begin);

                size_t m_remaining = 0;
                bytesConstRef m_currentItem;
        };

        iterator begin() const { return iterator(*this, true); }

        iterator end() const { return iterator(*this, false); }

        template <class T> inline T convert(int _flags) const;

        explicit operator std::string() const { return toString(); }
        explicit operator bytes() const { return toBytes(); }
        explicit operator RLPs() const { return toList(); }
        explicit operator uint8_t() const { return toInt<uint8_t>(); }
        explicit operator uint16_t() const { return toInt<uint16_t>(); }
        explicit operator uint32_t() const { return toInt<uint32_t>(); }
        explicit operator uint64_t() const { return toInt<uint64_t>(); }
        explicit operator u160() const { return toInt<u160>(); }
        explicit operator u256() const { return toInt<u256>(); }
        explicit operator bigint() const { return toInt<bigint>(); }
        template <unsigned N> explicit operator FixedHash<N>() const { return toHash<FixedHash<N>>(); }
        template <class T, class U> explicit operator std::pair<T, U>() const { return toPair<T, U>(); }
        template <class T> explicit operator std::vector<T>() const { return toVector<T>(); }
        template <class T> explicit operator std::set<T>() const { return toSet<T>(); }
        template <class T, size_t N> explicit operator std::array<T, N>() const { return toArray<T, N>(); }

        bytes toBytes(int _flags = LaissezFaire) const { if (!isData()) { if (_flags & ThrowOnFail) BOOST_THROW_EXCEPTION(BadCast()); else return bytes(); } return bytes(payload().data(), payload().data() + length()); }
        bytesConstRef toBytesConstRef(int _flags = LaissezFaire) const { if (!isData()) { if (_flags & ThrowOnFail) BOOST_THROW_EXCEPTION(BadCast()); else return bytesConstRef(); } return payload().cropped(0, length()); }
        std::string toString(int _flags = LaissezFaire) const { if (!isData()) { if (_flags & ThrowOnFail) BOOST_THROW_EXCEPTION(BadCast()); else return std::string(); } return payload().cropped(0, length()).toString(); }
        std::string toStringStrict() const { return toString(Strict); }

        template <class T>
        std::vector<T> toVector(int _flags = LaissezFaire) const
        {
                std::vector<T> ret;
                if (isList())
                {
                        ret.reserve(itemCount());
                        for (auto const& i: *this)
                                ret.push_back(i.convert<T>(_flags));
                 }
                else if (_flags & ThrowOnFail)
                        BOOST_THROW_EXCEPTION(BadCast());
                 return ret;
        }

        template <class T>
        std::set<T> toSet(int _flags = LaissezFaire) const
        {
                std::set<T> ret;
                if (isList())
                        for (auto const& i: *this)
                                ret.insert(i.convert<T>(_flags));
                else if (_flags & ThrowOnFail)
                        BOOST_THROW_EXCEPTION(BadCast());
                return ret;
        }

        template <class T>
        std::unordered_set<T> toUnorderedSet(int _flags = LaissezFaire) const
        {
                std::unordered_set<T> ret;
                if (isList())
                        for (auto const& i: *this)
                                ret.insert(i.convert<T>(_flags));
                else if (_flags & ThrowOnFail)
                        BOOST_THROW_EXCEPTION(BadCast());
                return ret;
        }

        template <class T, class U>
        std::pair<T, U> toPair(int _flags = Strict) const
        {
                std::pair<T, U> ret;
                if (itemCountStrict() != 2)
                {
                        if (_flags & ThrowOnFail)
                                BOOST_THROW_EXCEPTION(BadCast());
                        else
                                return ret;
                }
                ret.first = (*this)[0].convert<T>(_flags);
                ret.second = (*this)[1].convert<U>(_flags);
                return ret;
        }

        template <class T, size_t N>
        std::array<T, N> toArray(int _flags = LaissezFaire) const
        {
                if (itemCountStrict() != N)
                {
                        if (_flags & ThrowOnFail)
                                BOOST_THROW_EXCEPTION(BadCast());
                        else
                                return std::array<T, N>();
                }
                std::array<T, N> ret;
                for (size_t i = 0; i < N; ++i)
                        ret[i] = operator[](i).convert<T>(_flags);
                return ret;
        }

        template <class _T = unsigned> _T toInt(int _flags = Strict) const
        {
                requireGood();
                if ((!isInt() && !(_flags & AllowNonCanon)) || isList() || isNull())
                {
                        if (_flags & ThrowOnFail)
                                BOOST_THROW_EXCEPTION(BadCast());
                        else
                                return 0;
                }

                auto p = payload();
                if (p.size() > intTraits<_T>::maxSize && (_flags & FailIfTooBig))
                {
                        if (_flags & ThrowOnFail)
                                BOOST_THROW_EXCEPTION(BadCast());
                        else
                                return 0;
                }

                return fromBigEndian<_T>(p);
        }

        template <class _N> _N toHash(int _flags = Strict) const
        {
                requireGood();
                auto p = payload();
                auto l = p.size();
                if (!isData() || (l > _N::size && (_flags & FailIfTooBig)) || (l < _N::size && (_flags & FailIfTooSmall)))
                {
                        if (_flags & ThrowOnFail)
                                BOOST_THROW_EXCEPTION(BadCast());
                        else
                                return _N();
                }

                _N ret;
                size_t s = std::min<size_t>(_N::size, l);
                memcpy(ret.data() + _N::size - s, p.data(), s);
                return ret;
        }

        RLPs toList(int _flags = Strict) const;

        bytesConstRef payload() const { auto l = length(); if (l > m_data.size()) BOOST_THROW_EXCEPTION(BadRLP()); return m_data.cropped(payloadOffset(), l); }

        size_t actualSize() const;

private:
        explicit RLP(bytes const&&) {}

        void requireGood() const;

        bool isSingleByte() const { return !isNull() && m_data[0] < c_rlpDataImmLenStart; }

        unsigned lengthSize() const { if (isData() && m_data[0] > c_rlpDataIndLenZero) return m_data[0] - c_rlpDataIndLenZero; if (isList() && m_data[0] > c_rlpListIndLenZero) return m_data[0] - c_rlpListIndLenZero; return 0; }

        size_t length() const;

        size_t payloadOffset() const { return isSingleByte() ? 0 : (1 + lengthSize()); }

        size_t items() const;

        static size_t sizeAsEncoded(bytesConstRef _data) { return RLP(_data, ThrowOnFail | FailIfTooSmall).actualSize(); }

        bytesConstRef m_data;

        mutable size_t m_lastIndex = (size_t)-1;
        mutable size_t m_lastEnd = 0;
        mutable bytesConstRef m_lastItem;
};

template <> struct Converter<std::string> { static std::string convert(RLP const& _r, int _flags) { return _r.toString(_flags); } };
template <> struct Converter<bytes> { static bytes convert(RLP const& _r, int _flags) { return _r.toBytes(_flags); } };
template <> struct Converter<RLPs> { static RLPs convert(RLP const& _r, int _flags) { return _r.toList(_flags); } };
template <> struct Converter<uint8_t> { static uint8_t convert(RLP const& _r, int _flags) { return _r.toInt<uint8_t>(_flags); } };
template <> struct Converter<uint16_t> { static uint16_t convert(RLP const& _r, int _flags) { return _r.toInt<uint16_t>(_flags); } };
template <> struct Converter<uint32_t> { static uint32_t convert(RLP const& _r, int _flags) { return _r.toInt<uint32_t>(_flags); } };
template <> struct Converter<uint64_t> { static uint64_t convert(RLP const& _r, int _flags) { return _r.toInt<uint64_t>(_flags); } };
template <> struct Converter<u160> { static u160 convert(RLP const& _r, int _flags) { return _r.toInt<u160>(_flags); } };
template <> struct Converter<u256> { static u256 convert(RLP const& _r, int _flags) { return _r.toInt<u256>(_flags); } };
template <> struct Converter<bigint> { static bigint convert(RLP const& _r, int _flags) { return _r.toInt<bigint>(_flags); } };
template <unsigned N> struct Converter<FixedHash<N>> { static FixedHash<N> convert(RLP const& _r, int _flags) { return _r.toHash<FixedHash<N>>(_flags); } };
template <class T, class U> struct Converter<std::pair<T, U>> { static std::pair<T, U> convert(RLP const& _r, int _flags) { return _r.toPair<T, U>(_flags); } };
template <class T> struct Converter<std::vector<T>> { static std::vector<T> convert(RLP const& _r, int _flags) { return _r.toVector<T>(_flags); } };
template <class T> struct Converter<std::set<T>> { static std::set<T> convert(RLP const& _r, int _flags) { return _r.toSet<T>(_flags); } };
template <class T> struct Converter<std::unordered_set<T>> { static std::unordered_set<T> convert(RLP const& _r, int _flags) { return _r.toUnorderedSet<T>(_flags); } };
template <class T, size_t N> struct Converter<std::array<T, N>> { static std::array<T, N> convert(RLP const& _r, int _flags) { return _r.toArray<T, N>(_flags); } };

template <class T> inline T RLP::convert(int _flags) const { return Converter<T>::convert(*this, _flags); }

class RLPStream
{
public:
        RLPStream() {}

        explicit RLPStream(size_t _listItems) { appendList(_listItems); }

        ~RLPStream() {}

        RLPStream& append(unsigned _s) { return append(bigint(_s)); }
        RLPStream& append(u160 _s) { return append(bigint(_s)); }
        RLPStream& append(u256 _s) { return append(bigint(_s)); }
        RLPStream& append(bigint _s);
        RLPStream& append(bytesConstRef _s, bool _compact = false);
        RLPStream& append(bytes const& _s) { return append(bytesConstRef(&_s)); }
        RLPStream& append(std::string const& _s) { return append(bytesConstRef(_s)); }
        RLPStream& append(char const* _s) { return append(std::string(_s)); }
        template <unsigned N> RLPStream& append(FixedHash<N> _s, bool _compact = false, bool _allOrNothing = false) { return _allOrNothing && !_s ? append(bytesConstRef()) : append(_s.ref(), _compact); }

        RLPStream& append(RLP const& _rlp, size_t _itemCount = 1) { return appendRaw(_rlp.data(), _itemCount); }

        template <class _T> RLPStream& append(std::vector<_T> const& _s) { return appendVector(_s); }
        template <class _T> RLPStream& appendVector(std::vector<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
        template <class _T, size_t S> RLPStream& append(std::array<_T, S> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
        template <class _T> RLPStream& append(std::set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
        template <class _T> RLPStream& append(std::unordered_set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
        template <class T, class U> RLPStream& append(std::pair<T, U> const& _s) { appendList(2); append(_s.first); append(_s.second); return *this; }

        RLPStream& appendList(size_t _items);
        RLPStream& appendList(bytesConstRef _rlp);
        RLPStream& appendList(bytes const& _rlp) { return appendList(&_rlp); }
        RLPStream& appendList(RLPStream const& _s) { return appendList(&_s.out()); }

        RLPStream& appendRaw(bytesConstRef _rlp, size_t _itemCount = 1);
        RLPStream& appendRaw(bytes const& _rlp, size_t _itemCount = 1) { return appendRaw(&_rlp, _itemCount); }

        template <class T> RLPStream& operator<<(T _data) { return append(_data); }

        void clear() { m_out.clear(); m_listStack.clear(); }

        bytes const& out() const { if(!m_listStack.empty()) BOOST_THROW_EXCEPTION(RLPException() << errinfo_comment("listStack is not empty")); return m_out; }

        bytes&& invalidate() { if(!m_listStack.empty()) BOOST_THROW_EXCEPTION(RLPException() << errinfo_comment("listStack is not empty")); return std::move(m_out); }

        void swapOut(bytes& _dest) { if(!m_listStack.empty()) BOOST_THROW_EXCEPTION(RLPException() << errinfo_comment("listStack is not empty")); swap(m_out, _dest); }

private:
        void noteAppended(size_t _itemCount = 1);

        void pushCount(size_t _count, byte _offset);

        template <class _T> void pushInt(_T _i, size_t _br)
        {
                m_out.resize(m_out.size() + _br);
                byte* b = &m_out.back();
                for (; _i; _i >>= 8)
                        *(b--) = toUint8(_i);
        }

        bytes m_out;

        std::vector<std::pair<size_t, size_t>> m_listStack;
};

template <class _T> void rlpListAux(RLPStream& _out, _T _t) { _out << _t; }
template <class _T, class ... _Ts> void rlpListAux(RLPStream& _out, _T _t, _Ts ... _ts) { rlpListAux(_out << _t, _ts...); }

template <class _T> bytes rlp(_T _t) { return (RLPStream() << _t).out(); }

inline bytes rlpList() { return RLPStream(0).out(); }
template <class ... _Ts> bytes rlpList(_Ts ... _ts)
{
        RLPStream out(sizeof ...(_Ts));
        rlpListAux(out, _ts...);
        return out.out();
}

extern bytes RLPNull;

extern bytes RLPEmptyList;

std::ostream& operator<<(std::ostream& _out, dev::RLP const& _d);

}