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diff --git a/libevmasm/PathGasMeter.h b/libevmasm/PathGasMeter.h
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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 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;
+};
+
+}
+}