* add decoding measurement using stopwatch.h (use -v option)

* support PNG output through WIC on Win32

Change-Id: I1dbcc6ab1360010aca25da80f30a74781aadc76d

examples/stopwatch.h

@@ -0,0 +1,47 @@
+// Copyright 2011 Google Inc.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+//  Helper functions to measure elapsed time.
+//
+// Author: Mikolaj Zalewski (mikolajz@google.com)
+
+#ifndef WEBP_EXAMPLES_STOPWATCH_H_
+#define WEBP_EXAMPLES_STOPWATCH_H_
+
+#ifdef _WIN32
+#include <windows.h>
+
+typedef LARGE_INTEGER Stopwatch;
+
+static inline double StopwatchReadAndReset(Stopwatch* watch) {
+  const LARGE_INTEGER old_value = *watch;
+  LARGE_INTEGER freq;
+  if (!QueryPerformanceCounter(watch))
+    return 0.0;
+  if (!QueryPerformanceFrequency(&freq))
+    return 0.0;
+  if (freq.QuadPart == 0)
+    return 0.0;
+  return (watch->QuadPart - old_value.QuadPart) / (double)freq.QuadPart;
+}
+
+
+#else    // !_WIN32
+#include <sys/time.h>
+
+typedef struct timeval Stopwatch;
+
+static inline double StopwatchReadAndReset(Stopwatch* watch) {
+  const struct timeval old_value = *watch;
+  gettimeofday(watch, NULL);
+  return watch->tv_sec - old_value.tv_sec +
+      (watch->tv_usec - old_value.tv_usec) / 1000000.0;
+}
+
+#endif   // !_WIN32
+
+#endif  // WEBP_EXAMPLES_STOPWATCH_H_