Higher resolution timers for bench.
http://codereview.appspot.com/4548090/


git-svn-id: http://skia.googlecode.com/svn/trunk@1534 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/BenchSysTimer_windows.cpp b/bench/BenchSysTimer_windows.cpp
new file mode 100644
index 0000000..923754c
--- /dev/null
+++ b/bench/BenchSysTimer_windows.cpp
@@ -0,0 +1,55 @@
+#include "BenchSysTimer_windows.h"
+
+//Time
+#define WIN32_LEAN_AND_MEAN 1
+#include <Windows.h>
+
+static ULONGLONG winCpuTime() {
+    FILETIME createTime;
+    FILETIME exitTime;
+    FILETIME usrTime;
+    FILETIME sysTime;
+    if (0 == GetProcessTimes(GetCurrentProcess()
+                           , &createTime, &exitTime
+                           , &sysTime, &usrTime))
+    {
+        return 0;
+    }
+    ULARGE_INTEGER start_cpu_sys;
+    ULARGE_INTEGER start_cpu_usr;
+    start_cpu_sys.LowPart  = sysTime.dwLowDateTime;
+    start_cpu_sys.HighPart = sysTime.dwHighDateTime;
+    start_cpu_usr.LowPart  = usrTime.dwLowDateTime;
+    start_cpu_usr.HighPart = usrTime.dwHighDateTime;
+    return start_cpu_sys.QuadPart + start_cpu_usr.QuadPart;
+}
+
+void BenchSysTimer::startWall() {
+    if (0 == ::QueryPerformanceCounter(&this->fStartWall)) {
+        this->fStartWall.QuadPart = 0;
+    }
+}
+void BenchSysTimer::startCpu() {
+    this->fStartCpu = winCpuTime();
+}
+
+double BenchSysTimer::endCpu() {
+    ULONGLONG end_cpu = winCpuTime();
+    return (end_cpu - this->fStartCpu) / 10000;
+}
+double BenchSysTimer::endWall() {
+    LARGE_INTEGER end_wall;
+    if (0 == ::QueryPerformanceCounter(&end_wall)) {
+        end_wall.QuadPart = 0;
+    }
+    
+    LARGE_INTEGER ticks_elapsed;
+    ticks_elapsed.QuadPart = end_wall.QuadPart - this->fStartWall.QuadPart;
+    
+    LARGE_INTEGER frequency;
+    if (0 == ::QueryPerformanceFrequency(&frequency)) {
+        return 0;
+    } else {
+        return (double)ticks_elapsed.QuadPart / frequency.QuadPart * 1000;
+    }
+}