Misc: Os.currentTimeNanos() Windows implementation

core/src/main/c/windows/os.c

@@ -29,6 +29,7 @@
 #include <sspi.h>
 #include <issper16.h>
 #include <rpc.h>
+#include <sys/timeb.h>
 #include "../share/os.h"
 #include "errno.h"
 #include "timer.h"
@@ -132,6 +133,51 @@ JNIEXPORT jint JNICALL Java_com_questdb_std_Os_setCurrentThreadAffinity0
 }
 
 
+#define exp7           10000000LL     //1E+7     //C-file part
+#define exp9         1000000000LL     //1E+9
+#define w2ux 116444736000000000LL     //1.jan1601 to 1.jan1970
+
+void unix_time(struct timespec *spec) {
+    __int64 wintime;
+    GetSystemTimeAsFileTime((FILETIME *) &wintime);
+    wintime -= w2ux;
+    spec->tv_sec = wintime / exp7;
+    spec->tv_nsec = wintime % exp7 * 100;
+}
+
+int clock_gettime(struct timespec *spec) {
+    static struct timespec startspec;
+    static double ticks2nano;
+    static __int64 startticks, tps = 0;
+    __int64 tmp, curticks;
+
+    QueryPerformanceFrequency((LARGE_INTEGER *) &tmp);
+
+    if (tps != tmp) {
+        tps = tmp; //init ~~ONCE
+        // possibly change freq ?
+        QueryPerformanceCounter((LARGE_INTEGER *) &startticks);
+        unix_time(&startspec);
+        ticks2nano = (double) exp9 / tps;
+    }
+    QueryPerformanceCounter((LARGE_INTEGER *) &curticks);
+    curticks -= startticks;
+    spec->tv_sec = startspec.tv_sec + (curticks / tps);
+    spec->tv_nsec = (long) (startspec.tv_nsec + (double) (curticks % tps) * ticks2nano);
+    if (spec->tv_nsec >= exp9) {
+        spec->tv_sec++;
+        spec->tv_nsec -= exp9;
+    }
+    return 0;
+}
+
+JNIEXPORT jlong JNICALL Java_com_questdb_std_Os_currentTimeNanos
+        (JNIEnv *e, jclass cl) {
+    struct timespec spec;
+    clock_gettime(&spec);
+    return spec.tv_sec * 1000000000 + spec.tv_nsec;
+}
+
 JNIEXPORT void JNICALL Java_com_questdb_std_Os_freeKrbToken
         (JNIEnv *e, jclass cl, jlong ptr) {
 

core/src/test/java/com/questdb/std/OsTest.java

@@ -61,7 +61,10 @@ public class OsTest {
     public void testCurrentTimeNanos() {
         long reference = System.currentTimeMillis();
         long actual = Os.currentTimeNanos();
+        Assert.assertTrue(actual > 0);
         long delta = actual / 1_000_000 - reference;
         Assert.assertTrue(delta < 200);
+        System.out.println(reference);
+        System.out.println(actual);
     }
 }
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