First draft of (experimental) benchmarking support

include/internal/catch_benchmark.cpp

@@ -0,0 +1,30 @@
+/*
+ *  Created by Phil on 04/07/2017.
+ *  Copyright 2017 Two Blue Cubes Ltd. All rights reserved.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+#include "catch_benchmark.h"
+#include "catch_capture.hpp"
+
+namespace Catch {
+
+    void BenchmarkLooper::reportStart() const {
+        getResultCapture().benchmarkStarting( { m_name } );
+    }
+    auto BenchmarkLooper::needsMoreIterations() -> bool {
+        auto elapsed = m_timer.getElapsedNanoseconds();
+
+        // Exponentially increasing iterations until we're confident in our timer resolution
+        if( elapsed < m_resolution ) {
+            m_iterationsToRun *= 10;
+            return true;
+        }
+
+        getResultCapture().benchmarkEnded( { { m_name }, m_count, elapsed } );
+        return false;
+    }
+
+} // end namespace Catch