gentlsrc: use GEV buffer timestamps if available for unix reference time

common/get_unix_ns.h

@@ -0,0 +1,43 @@
+#ifndef _GET_UNIX_NS_H_
+#define _GET_UNIX_NS_H_
+
+#include <gmodule.h>
+
+typedef struct _MYFILETIME
+{
+  guint32 dwLowDateTime;
+  guint32 dwHighDateTime;
+} MYFILETIME;
+typedef void (*GetSystemTimeFunc) (MYFILETIME * lpSystemTimeAsFileTime);
+
+static guint64
+get_unix_ns ()
+{
+  MYFILETIME ftime;
+  LARGE_INTEGER ltime;
+  static GetSystemTimeFunc time_func = NULL;
+  if (!time_func) {
+    GModule *module;
+    module = g_module_open ("Kernel32.dll", G_MODULE_BIND_LAZY);
+    if (module) {
+      if (!g_module_symbol (module, "GetSystemTimePreciseAsFileTime",
+              (gpointer *) & time_func) || time_func == NULL) {
+        GST_WARNING
+            ("Couldn't find GetSystemTimePreciseAsFileTime, falling back to GetSystemTimeAsFileTime");
+        if (!g_module_symbol (module, "GetSystemTimeAsFileTime",
+                (gpointer *) & time_func) || time_func == NULL) {
+          GST_WARNING
+              ("Couldn't find GetSystemTimeAsFileTime, something is very wrong");
+        }
+      }
+    }
+  }
+  //GetSystemTimePreciseAsFileTime(&ftime);
+  time_func (&ftime);
+  ltime.HighPart = ftime.dwHighDateTime;
+  ltime.LowPart = ftime.dwLowDateTime;
+  ltime.QuadPart -= 11644473600000 * 10000;
+  return ltime.QuadPart * 100;
+}
+
+#endif /* _GET_UNIX_NS_H_ */