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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/>.
*/
/** @file Ethasher.cpp
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#include <boost/detail/endian.hpp>
#include <boost/filesystem.hpp>
#include <chrono>
#include <array>
#include <random>
#include <thread>
#include <libdevcore/Common.h>
#include <libdevcore/Guards.h>
#include <libdevcore/Log.h>
#include <libdevcrypto/CryptoPP.h>
#include <libdevcrypto/FileSystem.h>
#include <libethcore/Params.h>
#include <libethash/ethash.h>
#include "BlockInfo.h"
#include "Ethasher.h"
using namespace std;
using namespace chrono;
using namespace dev;
using namespace eth;
Ethasher* dev::eth::Ethasher::s_this = nullptr;
bytes const& Ethasher::cache(BlockInfo const& _header)
{
RecursiveGuard l(x_this);
if (_header.number > EPOCH_LENGTH*2048) {
std::ostringstream error;
error << "block number is too high; max is " << EPOCH_LENGTH*2048 << "(was " << _header.number << ")";
throw std::invalid_argument( error.str() );
}
if (!m_caches.count(_header.seedHash()))
{
ethash_params p = params((unsigned)_header.number);
m_caches[_header.seedHash()].resize(p.cache_size);
ethash_prep_light(m_caches[_header.seedHash()].data(), &p, _header.seedHash().data());
}
return m_caches[_header.seedHash()];
}
bytesConstRef Ethasher::full(BlockInfo const& _header)
{
RecursiveGuard l(x_this);
if (!m_fulls.count(_header.seedHash()))
{
if (!m_fulls.empty())
{
delete [] m_fulls.begin()->second.data();
m_fulls.erase(m_fulls.begin());
}
try {
boost::filesystem::create_directories(getDataDir() + "/ethashcache");
} catch (...) {}
std::string memoFile = getDataDir() + "/ethashcache/" + toHex(_header.seedHash().ref().cropped(0, 4)) + ".full";
m_fulls[_header.seedHash()] = contentsNew(memoFile);
if (!m_fulls[_header.seedHash()])
{
ethash_params p = params((unsigned)_header.number);
m_fulls[_header.seedHash()] = bytesRef(new byte[p.full_size], p.full_size);
auto c = cache(_header);
ethash_prep_full(m_fulls[_header.seedHash()].data(), &p, c.data());
writeFile(memoFile, m_fulls[_header.seedHash()]);
}
}
return m_fulls[_header.seedHash()];
}
ethash_params Ethasher::params(BlockInfo const& _header)
{
return params((unsigned)_header.number);
}
ethash_params Ethasher::params(unsigned _n)
{
ethash_params p;
p.cache_size = ethash_get_cachesize(_n);
p.full_size = ethash_get_datasize(_n);
return p;
}
bool Ethasher::verify(BlockInfo const& _header)
{
if (_header.number >= ETHASH_EPOCH_LENGTH * 2048)
return false;
h256 boundary = u256((bigint(1) << 256) / _header.difficulty);
uint8_t quickHashOut[32];
ethash_quick_hash(
quickHashOut,
_header.headerHash(WithoutNonce).data(),
(uint64_t)(u64)_header.nonce,
_header.mixHash.data()
);
h256 quickHashOut256 = h256(quickHashOut, h256::ConstructFromPointer);
if (quickHashOut256 > boundary)
return false;
auto e = eval(_header, _header.nonce);
return (u256)e.value <= boundary && e.mixHash == _header.mixHash;
}
Ethasher::Result Ethasher::eval(BlockInfo const& _header, Nonce const& _nonce)
{
auto p = Ethasher::params(_header);
ethash_return_value r;
ethash_compute_light(&r, Ethasher::get()->cache(_header).data(), &p, _header.headerHash(WithoutNonce).data(), (uint64_t)(u64)_nonce);
return Result{h256(r.result, h256::ConstructFromPointer), h256(r.mix_hash, h256::ConstructFromPointer)};
}