Uptime: add ffTimeGetNow() and use it

src/common/time.h

@@ -7,6 +7,7 @@
 #ifdef _WIN32
     #include <synchapi.h>
     #include <profileapi.h>
+    #include <sysinfoapi.h>
 #else
     #include <time.h>
 #endif
@@ -26,6 +27,19 @@ static inline uint64_t ffTimeGetTick() //In msec
     #endif
 }
 
+static inline uint64_t ffTimeGetNow()
+{
+    #ifdef _WIN32
+        uint64_t timeNow;
+        GetSystemTimeAsFileTime((FILETIME*) &timeNow);
+        return (timeNow - 116444736000000000ull) / 10000ull;
+    #else
+        struct timespec timeNow;
+        clock_gettime(CLOCK_REALTIME, &timeNow);
+        return (uint64_t)((timeNow.tv_sec * 1000) + (timeNow.tv_nsec / 1000000));
+    #endif
+}
+
 static inline void ffTimeSleep(uint32_t msec)
 {
     #ifdef _WIN32