From 44932dc85a4fc20b4fbc1a27e1becfaffd7b130a Mon Sep 17 00:00:00 2001
From: cameel <cameel2@gmail.com>
Date: Wed, 5 Feb 2020 14:56:55 +0100
Subject: [PATCH] [yul-phaser] Base class for pair selections

---
 tools/CMakeLists.txt               |  2 ++
 tools/yulPhaser/PairSelections.cpp | 18 ++++++++++
 tools/yulPhaser/PairSelections.h   | 53 ++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)
 create mode 100644 tools/yulPhaser/PairSelections.cpp
 create mode 100644 tools/yulPhaser/PairSelections.h

diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 21c0b8c91..b26fd166f 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -23,6 +23,8 @@ add_executable(yul-phaser
 	yulPhaser/FitnessMetrics.cpp
 	yulPhaser/Chromosome.h
 	yulPhaser/Chromosome.cpp
+	yulPhaser/PairSelections.h
+	yulPhaser/PairSelections.cpp
 	yulPhaser/Selections.h
 	yulPhaser/Selections.cpp
 	yulPhaser/Program.h
diff --git a/tools/yulPhaser/PairSelections.cpp b/tools/yulPhaser/PairSelections.cpp
new file mode 100644
index 000000000..6e63e4710
--- /dev/null
+++ b/tools/yulPhaser/PairSelections.cpp
@@ -0,0 +1,18 @@
+/*
+	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/>.
+*/
+
+#include <tools/yulPhaser/PairSelections.h>
diff --git a/tools/yulPhaser/PairSelections.h b/tools/yulPhaser/PairSelections.h
new file mode 100644
index 000000000..c7e833932
--- /dev/null
+++ b/tools/yulPhaser/PairSelections.h
@@ -0,0 +1,53 @@
+/*
+	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/>.
+*/
+/**
+ * Contains an abstract base class representing a selection of pairs of elements from a collection
+ * and its concrete implementations.
+ */
+
+#pragma once
+
+#include <tuple>
+#include <vector>
+
+namespace solidity::phaser
+{
+
+/**
+ * Abstract base class for selections of pairs elements from a collection.
+ *
+ * An instance of this class represents a specific method of selecting a set of pairs of elements
+ * from containers of arbitrary sizes. The selected pairs always point at a subset of the elements
+ * from the container but may indicate the same element more than once. The pairs themselves can
+ * repeat too. The selection may or may not be fixed - it's up to a specific implementation whether
+ * subsequent calls for the same container produce the same indices or not.
+ *
+ * Derived classes are meant to override the @a materialise() method.
+ * This method is expected to produce pairs of selected elements given the size of the collection.
+ */
+class PairSelection
+{
+public:
+	PairSelection() = default;
+	PairSelection(PairSelection const&) = delete;
+	PairSelection& operator=(PairSelection const&) = delete;
+	virtual ~PairSelection() = default;
+
+	virtual std::vector<std::tuple<size_t, size_t>> materialise(size_t _poolSize) const = 0;
+};
+
+}