solidity/libevmasm/PathGasMeter.h
2016-03-21 11:55:45 +03:00

67 lines
1.6 KiB
C++

/*
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 PathGasMeter.cpp
* @author Christian <c@ethdev.com>
* @date 2015
*/
#pragma once
#include <set>
#include <vector>
#include <memory>
#include <libevmasm/GasMeter.h>
namespace dev
{
namespace eth
{
class KnownState;
struct GasPath
{
size_t index = 0;
std::shared_ptr<KnownState> state;
u256 largestMemoryAccess;
GasMeter::GasConsumption gas;
std::set<size_t> visitedJumpdests;
};
/**
* Computes an upper bound on the gas usage of a computation starting at a certain position in
* a list of AssemblyItems in a given state until the computation stops.
* Can be used to estimate the gas usage of functions on any given input.
*/
class PathGasMeter
{
public:
PathGasMeter(AssemblyItems const& _items);
GasMeter::GasConsumption estimateMax(size_t _startIndex, std::shared_ptr<KnownState> const& _state);
private:
GasMeter::GasConsumption handleQueueItem();
std::vector<std::unique_ptr<GasPath>> m_queue;
std::map<u256, size_t> m_tagPositions;
AssemblyItems const& m_items;
};
}
}