Extract utility functions from ABI encoder.

libsolidity/codegen/MultiUseYulFunctionCollector.h

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+/*
+	This file is part of solidity.
+
+	solidity 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.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Container of (unparsed) Yul functions identified by name which are meant to be generated
+ * only once.
+ */
+
+#pragma once
+
+#include <functional>
+#include <map>
+#include <string>
+
+namespace dev
+{
+namespace solidity
+{
+
+/**
+ * Container of (unparsed) Yul functions identified by name which are meant to be generated
+ * only once.
+ */
+class MultiUseYulFunctionCollector
+{
+public:
+	/// Helper function that uses @a _creator to create a function and add it to
+	/// @a m_requestedFunctions if it has not been created yet and returns @a _name in both
+	/// cases.
+	std::string createFunction(std::string const& _name, std::function<std::string()> const& _creator);
+
+	/// @returns concatenation of all generated functions.
+	/// Clears the internal list, i.e. calling it again will result in an
+	/// empty return value.
+	std::string requestedFunctions();
+
+private:
+	/// Map from function name to code for a multi-use function.
+	std::map<std::string, std::string> m_requestedFunctions;
+};
+
+}
+}