From eea082ffd1a3ecf73b7c464cc28da5ef74d3a30f Mon Sep 17 00:00:00 2001
From: Bardur Arantsson <bardur@scientician.net>
Date: Sat, 17 Sep 2016 09:58:15 +0200
Subject: Add grid<> template class for representing 2D grids

---
 src/CMakeLists.txt |  1 +
 src/grid.hpp       | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/grid.cc      | 52 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 src/grid.hpp
 create mode 100644 tests/grid.cc

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7d64a66f..bf970c59 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -122,6 +122,7 @@ SET(SRCS_TESTS
   ../tests/harness.cc
   ../tests/lua_get_level.cc
   ../tests/flag_set.cc
+  ../tests/grid.cc
 )
 
 ADD_LIBRARY(game
diff --git a/src/grid.hpp b/src/grid.hpp
new file mode 100644
index 00000000..4708811d
--- /dev/null
+++ b/src/grid.hpp
@@ -0,0 +1,72 @@
+#pragma once
+
+#include <boost/multi_array.hpp>
+
+/**
+ * 2D grid of T's.
+ */
+template <typename T>
+struct grid {
+
+private:
+	boost::multi_array<T, 2> impl;
+
+public:
+	/**
+	 * Get reference to tile.
+	 */
+	T &operator ()(std::size_t x, std::size_t y)
+	{
+		return impl[y][x];
+	}
+
+	/**
+	 * Get const reference to tile.
+	 */
+	T const &operator ()(std::size_t x, std::size_t y) const
+	{
+		return impl[y][x];
+	}
+
+	/**
+	 * Resize grid. There is no guarantee whether
+	 * existing elements will be preserved or not.
+	 */
+	void resize(std::size_t width, std::size_t height)
+	{
+		impl.resize(boost::extents[height][width]);
+	}
+
+	/**
+	 * Get current width.
+	 */
+	std::size_t width() const
+	{
+		return impl.shape()[1];
+	}
+
+	/**
+	 * Get current height.
+	 */
+	std::size_t height() const
+	{
+		return impl.shape()[0];
+	}
+
+	/**
+	 * Set width. Same caveats apply as for resize().
+	 */
+	void width(std::size_t width)
+	{
+		resize(width, height());
+	}
+
+	/**
+	 * Set height. Same caveats apply as for resize().
+	 */
+	void height(std::size_t height)
+	{
+		resize(width(), height);
+	}
+
+};
diff --git a/tests/grid.cc b/tests/grid.cc
new file mode 100644
index 00000000..ff618088
--- /dev/null
+++ b/tests/grid.cc
@@ -0,0 +1,52 @@
+#include "grid.hpp"
+#include <bandit/bandit.h>
+using namespace bandit;
+
+go_bandit([]() {
+	describe("grid<>", []() {
+
+		auto w0 = size_t { 123 };
+		auto h0 = size_t { 42 };
+
+		it("width(...) properly sets returned width", [&](){
+			// Setup
+			grid<int> g;
+			// Exercise
+			g.width(w0);
+			// Verify
+			AssertThat(g.width(), Equals(w0));
+		});
+
+		it("height(...) properly sets returned height", [&](){
+			// Setup
+			grid<int> g;
+			// Exercise
+			g.height(h0);
+			// Verify
+			AssertThat(g.height(), Equals(h0));
+		});
+
+		it("resize(w, h) properly sets returned width and height", [&](){
+			// Setup
+			grid<int> g;
+			// Exercise
+			g.resize(w0, h0);
+			// Verify
+			AssertThat(g.width(), Equals(w0));
+			AssertThat(g.height(), Equals(h0));
+		});
+
+		it("operator () can access ((w-1), (h-1)) element", [&](){
+			// Class with 'magic' default value
+			struct X { int magic = 1001; };
+			// Setup
+			grid<X> g;
+			g.resize(w0 + 1, h0 + 1);
+			// Exercise
+			auto x = g(w0, h0);
+			// Verify
+			AssertThat(x.magic, Equals(1001));
+		});
+
+	});
+});
-- 
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