fixup! Benchmark: emulate clock_gettime(2) on Windows

test/benchmark.c

@@ -13,7 +13,7 @@
 #include <stdio.h>
 #include <time.h>
 
-#ifdef _WIN32
+#if defined(_WIN32) || defined(_WIN64)
 #  include <windows.h>
 #  include <wincrypt.h>
 #else
@@ -66,7 +66,7 @@ bytes_to_mb (size_t bytes)
 static bool
 get_random_data (struct buffers *b, char **errmsg)
 {
-#ifdef _WIN32
+#if defined(_WIN32) || defined(_WIN64)
 	HCRYPTPROV hProvider = 0;
 
 	if (!CryptAcquireContext(&hProvider, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
@@ -130,18 +130,31 @@ timediff_sec (base64_timespec *start, base64_timespec *end)
 
 	return (float)((diff * tb.numer) / tb.denom) / 1e9f;
 }
-#elif defined(_WIN32) && !(defined(__MINGW32__) || defined(__MINGW64__))
-typedef struct timespec base64_timespec;
+#elif defined(_WIN32) || defined(_WIN64)
+typedef ULARGE_INTEGER base64_timespec;
+
 static void
 base64_gettime (base64_timespec *o_time)
 {
-	timespec_get(o_time, TIME_UTC);
+	FILETIME current_time_ft;
+
+	GetSystemTimePreciseAsFileTime(&current_time_ft);
+
+	o_time->LowPart  = current_time_ft.dwLowDateTime;
+	o_time->HighPart = current_time_ft.dwHighDateTime;
 }
 
 static float
 timediff_sec (base64_timespec *start, base64_timespec *end)
 {
-	return (end->tv_sec - start->tv_sec) + ((float)(end->tv_nsec - start->tv_nsec)) / 1e9f;
+	// Timer resolution is 100 nanoseconds (10^7).
+	const float ssec  = start->QuadPart / 10000000;
+	const float snsec = start->QuadPart % 10000000;
+
+	const float esec  = end->QuadPart / 10000000;
+	const float ensec = end->QuadPart % 10000000;
+
+	return (esec - ssec) + (ensec - snsec) / 1e7f;
 }
 #else
 typedef struct timespec base64_timespec;