1 files changed, 128 insertions, 0 deletions
diff --git a/include/gpu/GrStopwatch.h b/include/gpu/GrStopwatch.h
new file mode 100644
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+++ b/include/gpu/GrStopwatch.h
@@ -0,0 +1,128 @@
+
+/*
+ * Copyright 2010 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+
+#ifndef GrStopwatch_DEFINED
+#define GrStopwatch_DEFINED
+
+#include "GrTypes.h"
+
+template <typename PLATFORM_TIMER>
+/**
+ * Base class for stopwatch. Relies on PLATFORM_TIMER for platform-specific
+ * timer functions. PLATFORM_TIMER provides:
+ *      - typename TIMESTAMP : a timestamp value that can be used with Diff()
+ *      - static TIMESTAMP Now() : gets current timestamp
+ *      - static double Diff(const TIMESTAMP& begin, const TIMESTAMP& end) : 
+ *           computes delta in seconds between two timestamps
+ */
+class GrStopwatchBase {
+public:
+    /**
+     * Contructor - implicit reset()
+     */
+    GrStopwatchBase() {
+        fRunning = false;
+        fTotalElapsed = 0.0;        
+    }
+
+    /**
+     * begins a new lap
+     */
+    void start() {
+        double lastLap = lapTime();
+        fTotalElapsed += lastLap;
+        fRunning = true;
+        fLastStart = PLATFORM_TIMER::Now();
+    }
+    
+    /**
+     * ends current lap (or no effect if lap not started)
+     */
+    void stop() {
+        double lastLap = lapTime();
+        fTotalElapsed += lastLap;
+        fRunning = false;
+    }
+
+    /**
+     * ends current lap, resets total time
+     */
+    void reset() {
+        fRunning = false;
+        fTotalElapsed = 0.f;
+    }
+    
+    /**
+     * Computes the time of all laps since last reset() including current lap
+     * if lap is still running.
+     *
+     * @return the sum time in seconds of all laps since last reset().
+     */
+    double totalTime() const {
+        return fTotalElapsed + lapTime();
+    }
+
+    /**
+     * Current lap time.
+     *
+     * @return time in seconds of current lap if one is running otherwise 0.
+     */
+    double lapTime() const {
+        if (fRunning) {
+            PLATFORM_TIMER::Timestamp now = PLATFORM_TIMER::Now();
+            return PLATFORM_TIMER::Elapsed(fLastStart, now);
+        }
+        return 0.0;
+    }
+
+private:
+    double fTotalElapsed;
+
+    typename PLATFORM_TIMER::Timestamp fLastStart;
+    bool                               fRunning;
+};
+
+#if GR_WIN32_BUILD
+
+    #include <Windows.h>
+
+    class GrWin32Timer {
+    public:
+        typedef LARGE_INTEGER Timestamp;  
+
+        static Timestamp Now() {
+            LARGE_INTEGER now;
+            QueryPerformanceCounter(&now);
+            return now;
+        }
+
+        static double Elapsed(const Timestamp& begin, const Timestamp& end) {
+            double diff = (double)(end.QuadPart - begin.QuadPart);
+            return diff * Scale();
+        }
+    private:
+        static double Scale() {
+            static double scale;
+            if (0.0 == scale) {
+                LARGE_INTEGER freq;
+                QueryPerformanceFrequency(&freq);
+                GrAssert(0 != freq.QuadPart);
+                scale = 1 / (double) freq.QuadPart;
+            }
+            return scale;
+        }
+    };
+    typedef GrStopwatchBase<GrWin32Timer> GrStopwatch;
+#else
+    #error "Implement platform timer for stopwatch"
+#endif
+
+
+#endif