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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 EthashAux.cpp
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#include "EthashAux.h"
#include <libethash/internal.h>
using namespace std;
using namespace chrono;
using namespace dev;
using namespace eth;
h256 const& BlockHeaderRaw::seedHash() const
{
if (!m_seedHash)
m_seedHash = EthashAux::seedHash((unsigned)m_number);
return m_seedHash;
}
EthashAux* EthashAux::get()
{
static EthashAux instance;
return &instance;
}
h256 EthashAux::seedHash(unsigned _number)
{
unsigned epoch = _number / ETHASH_EPOCH_LENGTH;
Guard l(get()->x_epochs);
if (epoch >= get()->m_seedHashes.size())
{
h256 ret;
unsigned n = 0;
if (!get()->m_seedHashes.empty())
{
ret = get()->m_seedHashes.back();
n = get()->m_seedHashes.size() - 1;
}
get()->m_seedHashes.resize(epoch + 1);
for (; n <= epoch; ++n, ret = sha3(ret))
get()->m_seedHashes[n] = ret;
}
return get()->m_seedHashes[epoch];
}
uint64_t EthashAux::number(h256 const& _seedHash)
{
Guard l(get()->x_epochs);
unsigned epoch = 0;
auto epochIter = get()->m_epochs.find(_seedHash);
if (epochIter == get()->m_epochs.end())
{
for (h256 h; h != _seedHash && epoch < 2048; ++epoch, h = sha3(h), get()->m_epochs[h] = epoch) {}
if (epoch == 2048)
{
std::ostringstream error;
error << "apparent block number for " << _seedHash << " is too high; max is " << (ETHASH_EPOCH_LENGTH * 2048);
throw std::invalid_argument(error.str());
}
}
else
epoch = epochIter->second;
return epoch * ETHASH_EPOCH_LENGTH;
}
EthashAux::LightType EthashAux::light(h256 const& _seedHash)
{
Guard l(get()->x_lights);
if (get()->m_lights.count(_seedHash))
return get()->m_lights.at(_seedHash);
return (get()->m_lights[_seedHash] = make_shared<LightAllocation>(_seedHash));
}
EthashAux::LightAllocation::LightAllocation(h256 const& _seedHash)
{
uint64_t blockNumber = EthashAux::number(_seedHash);
light = ethash_light_new(blockNumber);
if (!light)
BOOST_THROW_EXCEPTION(ExternalFunctionFailure("ethash_light_new()"));
size = ethash_get_cachesize(blockNumber);
}
EthashAux::LightAllocation::~LightAllocation()
{
ethash_light_delete(light);
}
bytesConstRef EthashAux::LightAllocation::data() const
{
return bytesConstRef((byte const*)light->cache, size);
}
EthashProofOfWork::Result EthashAux::LightAllocation::compute(h256 const& _headerHash, Nonce const& _nonce) const
{
ethash_return_value r = ethash_light_compute(light, *(ethash_h256_t*)_headerHash.data(), (uint64_t)(u64)_nonce);
if (!r.success)
BOOST_THROW_EXCEPTION(DAGCreationFailure());
return EthashProofOfWork::Result{h256((uint8_t*)&r.result, h256::ConstructFromPointer), h256((uint8_t*)&r.mix_hash, h256::ConstructFromPointer)};
}
EthashProofOfWork::Result EthashAux::eval(h256 const& _seedHash, h256 const& _headerHash, Nonce const& _nonce) noexcept
{
try
{
return EthashAux::get()->light(_seedHash)->compute(_headerHash, _nonce);
}
catch(...)
{
return EthashProofOfWork::Result{~h256(), h256()};
}
}