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117 lines
3.2 KiB
117 lines
3.2 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 ProofOfWork.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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* ProofOfWork algorithm. Or not.
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*/
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#pragma once
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#include <chrono>
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#include <thread>
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#include <cstdint>
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#include <libdevcrypto/SHA3.h>
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#include "CommonEth.h"
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#define FAKE_DAGGER 1
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namespace dev
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{
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namespace eth
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{
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struct MineInfo
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{
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void combine(MineInfo const& _m) { requirement = std::max(requirement, _m.requirement); best = std::min(best, _m.best); hashes += _m.hashes; completed = completed || _m.completed; }
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double requirement = 0;
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double best = 1e99;
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unsigned hashes = 0;
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bool completed = false;
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};
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template <class Evaluator>
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class ProofOfWorkEngine: public Evaluator
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{
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public:
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static bool verify(h256 const& _root, h256 const& _nonce, u256 const& _difficulty) { return (bigint)(u256)Evaluator::eval(_root, _nonce) <= (bigint(1) << 256) / _difficulty; }
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inline MineInfo mine(h256& o_solution, h256 const& _root, u256 const& _difficulty, unsigned _msTimeout = 100, bool _continue = true, bool _turbo = false);
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protected:
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h256 m_last;
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};
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class SHA3Evaluator
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{
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public:
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static h256 eval(h256 const& _root, h256 const& _nonce) { h256 b[2] = { _root, _nonce }; return sha3(bytesConstRef((byte const*)&b[0], 64)); }
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};
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// TODO: class ARPoWEvaluator
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class DaggerEvaluator
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{
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public:
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static h256 eval(h256 const& _root, h256 const& _nonce);
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private:
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static h256 node(h256 const& _root, h256 const& _xn, uint_fast32_t _L, uint_fast32_t _i);
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};
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using SHA3ProofOfWork = ProofOfWorkEngine<SHA3Evaluator>;
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using ProofOfWork = SHA3ProofOfWork;
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template <class Evaluator>
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MineInfo ProofOfWorkEngine<Evaluator>::mine(h256& o_solution, h256 const& _root, u256 const& _difficulty, unsigned _msTimeout, bool _continue, bool _turbo)
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{
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MineInfo ret;
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static std::mt19937_64 s_eng((time(0) + (unsigned)m_last));
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u256 s = (m_last = h256::random(s_eng));
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bigint d = (bigint(1) << 256) / _difficulty;
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ret.requirement = log2((double)d);
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// 2^ 0 32 64 128 256
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// [--------*-------------------------]
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//
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// evaluate until we run out of time
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auto startTime = std::chrono::steady_clock::now();
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if (!_turbo)
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std::this_thread::sleep_for(std::chrono::milliseconds(_msTimeout * 90 / 100));
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for (; (std::chrono::steady_clock::now() - startTime) < std::chrono::milliseconds(_msTimeout) && _continue; s++, ret.hashes++)
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{
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o_solution = (h256)s;
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auto e = (bigint)(u256)Evaluator::eval(_root, o_solution);
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ret.best = std::min<double>(ret.best, log2((double)e));
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if (e <= d)
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{
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ret.completed = true;
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break;
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}
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}
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if (ret.completed)
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assert(verify(_root, o_solution, _difficulty));
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return ret;
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}
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}
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}
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