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436 lines
16 KiB
436 lines
16 KiB
/*
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This file is part of cpp-ethereum.
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cpp-ethereum is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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cpp-ethereum is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file RLP.h
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* @author Gav Wood <i@gavwood.com>
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* @date 2014
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*
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* RLP (de-)serialisation.
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*/
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#pragma once
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#include <vector>
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#include <array>
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#include <exception>
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#include <iostream>
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#include <iomanip>
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#include "vector_ref.h"
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#include "Common.h"
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#include "Exceptions.h"
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#include "FixedHash.h"
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namespace dev
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{
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class RLP;
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using RLPs = std::vector<RLP>;
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template <class _T> struct intTraits { static const unsigned maxSize = sizeof(_T); };
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template <> struct intTraits<u160> { static const unsigned maxSize = 20; };
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template <> struct intTraits<u256> { static const unsigned maxSize = 32; };
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template <> struct intTraits<bigint> { static const unsigned maxSize = ~(unsigned)0; };
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static const byte c_rlpMaxLengthBytes = 8;
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static const byte c_rlpDataImmLenStart = 0x80;
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static const byte c_rlpListStart = 0xc0;
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static const byte c_rlpDataImmLenCount = c_rlpListStart - c_rlpDataImmLenStart - c_rlpMaxLengthBytes;
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static const byte c_rlpDataIndLenZero = c_rlpDataImmLenStart + c_rlpDataImmLenCount - 1;
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static const byte c_rlpListImmLenCount = 256 - c_rlpListStart - c_rlpMaxLengthBytes;
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static const byte c_rlpListIndLenZero = c_rlpListStart + c_rlpListImmLenCount - 1;
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/**
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* @brief Class for interpreting Recursive Linear-Prefix Data.
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* @by Gav Wood, 2013
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*
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* Class for reading byte arrays of data in RLP format.
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*/
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class RLP
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{
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public:
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/// Conversion flags
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enum
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{
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AllowNonCanon = 1,
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ThrowOnFail = 4,
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FailIfTooBig = 8,
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FailIfTooSmall = 16,
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Strict = ThrowOnFail | FailIfTooBig,
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VeryStrict = ThrowOnFail | FailIfTooBig | FailIfTooSmall,
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LaisezFaire = AllowNonCanon
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};
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using Strictness = int;
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/// Construct a null node.
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RLP() {}
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/// Construct a node of value given in the bytes.
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explicit RLP(bytesConstRef _d, Strictness _s = VeryStrict);
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/// Construct a node of value given in the bytes.
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explicit RLP(bytes const& _d, Strictness _s = VeryStrict): RLP(&_d, _s) {}
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/// Construct a node to read RLP data in the bytes given.
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RLP(byte const* _b, unsigned _s, Strictness _st = VeryStrict): RLP(bytesConstRef(_b, _s), _st) {}
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/// Construct a node to read RLP data in the string.
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explicit RLP(std::string const& _s, Strictness _st = VeryStrict): RLP(bytesConstRef((byte const*)_s.data(), _s.size()), _st) {}
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/// The bare data of the RLP.
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bytesConstRef data() const { return m_data; }
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/// @returns true if the RLP is non-null.
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explicit operator bool() const { return !isNull(); }
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/// No value.
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bool isNull() const { return m_data.size() == 0; }
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/// Contains a zero-length string or zero-length list.
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bool isEmpty() const { return !isNull() && (m_data[0] == c_rlpDataImmLenStart || m_data[0] == c_rlpListStart); }
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/// String value.
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bool isData() const { return !isNull() && m_data[0] < c_rlpListStart; }
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/// List value.
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bool isList() const { return !isNull() && m_data[0] >= c_rlpListStart; }
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/// Integer value. Must not have a leading zero.
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bool isInt() const;
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/// @returns the number of items in the list, or zero if it isn't a list.
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unsigned itemCount() const { return isList() ? items() : 0; }
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unsigned itemCountStrict() const { if (!isList()) BOOST_THROW_EXCEPTION(BadCast()); return items(); }
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/// @returns the number of bytes in the data, or zero if it isn't data.
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unsigned size() const { return isData() ? length() : 0; }
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unsigned sizeStrict() const { if (!isData()) BOOST_THROW_EXCEPTION(BadCast()); return length(); }
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/// Equality operators; does best-effort conversion and checks for equality.
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bool operator==(char const* _s) const { return isData() && toString() == _s; }
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bool operator!=(char const* _s) const { return isData() && toString() != _s; }
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bool operator==(std::string const& _s) const { return isData() && toString() == _s; }
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bool operator!=(std::string const& _s) const { return isData() && toString() != _s; }
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template <unsigned _N> bool operator==(FixedHash<_N> const& _h) const { return isData() && toHash<_N>() == _h; }
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template <unsigned _N> bool operator!=(FixedHash<_N> const& _s) const { return isData() && toHash<_N>() != _s; }
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bool operator==(unsigned const& _i) const { return isInt() && toInt<unsigned>() == _i; }
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bool operator!=(unsigned const& _i) const { return isInt() && toInt<unsigned>() != _i; }
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bool operator==(u256 const& _i) const { return isInt() && toInt<u256>() == _i; }
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bool operator!=(u256 const& _i) const { return isInt() && toInt<u256>() != _i; }
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bool operator==(bigint const& _i) const { return isInt() && toInt<bigint>() == _i; }
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bool operator!=(bigint const& _i) const { return isInt() && toInt<bigint>() != _i; }
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/// Subscript operator.
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/// @returns the list item @a _i if isList() and @a _i < listItems(), or RLP() otherwise.
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/// @note if used to access items in ascending order, this is efficient.
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RLP operator[](unsigned _i) const;
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using element_type = RLP;
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/// @brief Iterator class for iterating through items of RLP list.
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class iterator
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{
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friend class RLP;
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public:
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using value_type = RLP;
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using element_type = RLP;
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iterator& operator++();
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iterator operator++(int) { auto ret = *this; operator++(); return ret; }
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RLP operator*() const { return RLP(m_lastItem); }
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bool operator==(iterator const& _cmp) const { return m_lastItem == _cmp.m_lastItem; }
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bool operator!=(iterator const& _cmp) const { return !operator==(_cmp); }
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private:
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iterator() {}
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iterator(RLP const& _parent, bool _begin);
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unsigned m_remaining = 0;
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bytesConstRef m_lastItem;
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};
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/// @brief Iterator into beginning of sub-item list (valid only if we are a list).
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iterator begin() const { return iterator(*this, true); }
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/// @brief Iterator into end of sub-item list (valid only if we are a list).
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iterator end() const { return iterator(*this, false); }
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/// Best-effort conversion operators.
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explicit operator std::string() const { return toString(); }
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explicit operator bytes() const { return toBytes(); }
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explicit operator RLPs() const { return toList(); }
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explicit operator uint8_t() const { return toInt<uint8_t>(); }
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explicit operator uint16_t() const { return toInt<uint16_t>(); }
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explicit operator uint32_t() const { return toInt<uint32_t>(); }
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explicit operator uint64_t() const { return toInt<uint64_t>(); }
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explicit operator u160() const { return toInt<u160>(); }
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explicit operator u256() const { return toInt<u256>(); }
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explicit operator bigint() const { return toInt<bigint>(); }
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template <unsigned _N> explicit operator FixedHash<_N>() const { return toHash<FixedHash<_N>>(); }
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template <class T, class U> explicit operator std::pair<T, U>() const { return toPair<T, U>(); }
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template <class T> explicit operator std::vector<T>() const { return toVector<T>(); }
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template <class T> explicit operator std::set<T>() const { return toSet<T>(); }
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template <class T, size_t N> explicit operator std::array<T, N>() const { return toArray<T, N>(); }
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/// Converts to bytearray. @returns the empty byte array if not a string.
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bytes toBytes() const { if (!isData()) return bytes(); return bytes(payload().data(), payload().data() + length()); }
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/// Converts to bytearray. @returns the empty byte array if not a string.
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bytesConstRef toBytesConstRef() const { if (!isData()) return bytesConstRef(); return payload().cropped(0, length()); }
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/// Converts to string. @returns the empty string if not a string.
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std::string toString() const { if (!isData()) return std::string(); return payload().cropped(0, length()).toString(); }
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/// Converts to string. @throws BadCast if not a string.
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std::string toStringStrict() const { if (!isData()) BOOST_THROW_EXCEPTION(BadCast()); return payload().cropped(0, length()).toString(); }
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template <class T>
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std::vector<T> toVector() const
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{
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std::vector<T> ret;
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if (isList())
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{
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ret.reserve(itemCount());
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for (auto const& i: *this)
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{
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ret.push_back((T)i);
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}
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}
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return ret;
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}
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template <class T>
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std::set<T> toSet() const
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{
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std::set<T> ret;
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if (isList())
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{
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for (auto const& i: *this)
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{
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ret.insert((T)i);
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}
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}
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return ret;
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}
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template <class T, class U>
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std::pair<T, U> toPair() const
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{
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std::pair<T, U> ret;
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if (isList())
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{
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ret.first = (T)(*this)[0];
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ret.second = (U)(*this)[1];
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}
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return ret;
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}
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template <class T, size_t N>
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std::array<T, N> toArray() const
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{
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if (itemCount() != N || !isList())
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BOOST_THROW_EXCEPTION(BadCast());
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std::array<T, N> ret;
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for (unsigned i = 0; i < N; ++i)
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{
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ret[i] = (T)operator[](i);
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}
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return ret;
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}
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/// Converts to int of type given; if isString(), decodes as big-endian bytestream. @returns 0 if not an int or string.
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template <class _T = unsigned> _T toInt(int _flags = Strict) const
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{
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requireGood();
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if ((!isInt() && !(_flags & AllowNonCanon)) || isList() || isNull())
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if (_flags & ThrowOnFail)
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BOOST_THROW_EXCEPTION(BadCast());
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else
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return 0;
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else {}
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auto p = payload();
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if (p.size() > intTraits<_T>::maxSize && (_flags & FailIfTooBig))
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if (_flags & ThrowOnFail)
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BOOST_THROW_EXCEPTION(BadCast());
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else
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return 0;
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else {}
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return fromBigEndian<_T>(p);
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}
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template <class _N> _N toHash(int _flags = Strict) const
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{
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requireGood();
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if (!isData() || (length() > _N::size && (_flags & FailIfTooBig)) || (length() < _N::size && (_flags & FailIfTooSmall)))
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if (_flags & ThrowOnFail)
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BOOST_THROW_EXCEPTION(BadCast());
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else
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return _N();
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else{}
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_N ret;
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size_t s = std::min((size_t)_N::size, (size_t)length());
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memcpy(ret.data() + _N::size - s, payload().data(), s);
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return ret;
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}
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/// Converts to RLPs collection object. Useful if you need random access to sub items or will iterate over multiple times.
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RLPs toList() const;
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/// @returns the data payload. Valid for all types.
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bytesConstRef payload() const { auto l = length(); if (l > m_data.size()) throw BadRLP(); return m_data.cropped(payloadOffset(), l); }
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/// @returns the theoretical size of this item.
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/// @note Under normal circumstances, is equivalent to m_data.size() - use that unless you know it won't work.
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unsigned actualSize() const;
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private:
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/// Disable construction from rvalue
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explicit RLP(bytes const&&) {}
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/// Throws if is non-canonical data (i.e. single byte done in two bytes that could be done in one).
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void requireGood() const;
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/// Single-byte data payload.
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bool isSingleByte() const { return !isNull() && m_data[0] < c_rlpDataImmLenStart; }
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/// @returns the amount of bytes used to encode the length of the data. Valid for all types.
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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; }
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/// @returns the size in bytes of the payload, as given by the RLP as opposed to as inferred from m_data.
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unsigned length() const;
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/// @returns the number of bytes into the data that the payload starts.
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unsigned payloadOffset() const { return isSingleByte() ? 0 : (1 + lengthSize()); }
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/// @returns the number of data items.
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unsigned items() const;
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/// Our byte data.
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bytesConstRef m_data;
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/// The list-indexing cache.
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mutable unsigned m_lastIndex = (unsigned)-1;
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mutable unsigned m_lastEnd = 0;
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mutable bytesConstRef m_lastItem;
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};
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/**
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* @brief Class for writing to an RLP bytestream.
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*/
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class RLPStream
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{
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public:
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/// Initializes empty RLPStream.
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RLPStream() {}
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/// Initializes the RLPStream as a list of @a _listItems items.
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explicit RLPStream(unsigned _listItems) { appendList(_listItems); }
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~RLPStream() {}
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/// Append given datum to the byte stream.
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RLPStream& append(unsigned _s) { return append(bigint(_s)); }
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RLPStream& append(u160 _s) { return append(bigint(_s)); }
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RLPStream& append(u256 _s) { return append(bigint(_s)); }
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RLPStream& append(bigint _s);
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RLPStream& append(bytesConstRef _s, bool _compact = false);
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RLPStream& append(bytes const& _s) { return append(bytesConstRef(&_s)); }
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RLPStream& append(std::string const& _s) { return append(bytesConstRef(_s)); }
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RLPStream& append(char const* _s) { return append(std::string(_s)); }
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template <unsigned N> RLPStream& append(FixedHash<N> _s, bool _compact = false, bool _allOrNothing = false) { return _allOrNothing && !_s ? append(bytesConstRef()) : append(_s.ref(), _compact); }
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/// Appends an arbitrary RLP fragment - this *must* be a single item unless @a _itemCount is given.
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RLPStream& append(RLP const& _rlp, unsigned _itemCount = 1) { return appendRaw(_rlp.data(), _itemCount); }
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/// Appends a sequence of data to the stream as a list.
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template <class _T> RLPStream& append(std::vector<_T> const& _s) { return appendVector(_s); }
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template <class _T> RLPStream& appendVector(std::vector<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
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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; }
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template <class _T> RLPStream& append(std::set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
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template <class _T> RLPStream& append(std::unordered_set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
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template <class T, class U> RLPStream& append(std::pair<T, U> const& _s) { appendList(2); append(_s.first); append(_s.second); return *this; }
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/// Appends a list.
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RLPStream& appendList(unsigned _items);
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RLPStream& appendList(bytesConstRef _rlp);
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RLPStream& appendList(bytes const& _rlp) { return appendList(&_rlp); }
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RLPStream& appendList(RLPStream const& _s) { return appendList(&_s.out()); }
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/// Appends raw (pre-serialised) RLP data. Use with caution.
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RLPStream& appendRaw(bytesConstRef _rlp, unsigned _itemCount = 1);
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RLPStream& appendRaw(bytes const& _rlp, unsigned _itemCount = 1) { return appendRaw(&_rlp, _itemCount); }
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/// Shift operators for appending data items.
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template <class T> RLPStream& operator<<(T _data) { return append(_data); }
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/// Clear the output stream so far.
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void clear() { m_out.clear(); m_listStack.clear(); }
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/// Read the byte stream.
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bytes const& out() const { if(!m_listStack.empty()) BOOST_THROW_EXCEPTION(RLPException() << errinfo_comment("listStack is not empty")); return m_out; }
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/// Swap the contents of the output stream out for some other byte array.
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void swapOut(bytes& _dest) { if(!m_listStack.empty()) BOOST_THROW_EXCEPTION(RLPException() << errinfo_comment("listStack is not empty")); swap(m_out, _dest); }
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private:
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void noteAppended(unsigned _itemCount = 1);
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/// Push the node-type byte (using @a _base) along with the item count @a _count.
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/// @arg _count is number of characters for strings, data-bytes for ints, or items for lists.
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void pushCount(unsigned _count, byte _offset);
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/// Push an integer as a raw big-endian byte-stream.
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template <class _T> void pushInt(_T _i, unsigned _br)
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{
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m_out.resize(m_out.size() + _br);
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byte* b = &m_out.back();
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for (; _i; _i >>= 8)
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*(b--) = (byte)_i;
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}
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/// Our output byte stream.
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bytes m_out;
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std::vector<std::pair<unsigned, unsigned>> m_listStack;
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};
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template <class _T> void rlpListAux(RLPStream& _out, _T _t) { _out << _t; }
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template <class _T, class ... _Ts> void rlpListAux(RLPStream& _out, _T _t, _Ts ... _ts) { rlpListAux(_out << _t, _ts...); }
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/// Export a single item in RLP format, returning a byte array.
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template <class _T> bytes rlp(_T _t) { return (RLPStream() << _t).out(); }
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/// Export a list of items in RLP format, returning a byte array.
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inline bytes rlpList() { return RLPStream(0).out(); }
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template <class ... _Ts> bytes rlpList(_Ts ... _ts)
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{
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RLPStream out(sizeof ...(_Ts));
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rlpListAux(out, _ts...);
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return out.out();
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}
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/// The empty string in RLP format.
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extern bytes RLPNull;
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/// The empty list in RLP format.
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extern bytes RLPEmptyList;
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/// Human readable version of RLP.
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std::ostream& operator<<(std::ostream& _out, dev::RLP const& _d);
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}
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