windows: Add usleep() implementation for msvc port

Also make sleep.c self-contained by moving initialization code,
instead of having part of the code in init.c, and add a header file
to accomodate this.
msec_sleep() now uses the usleep() implementation as well.

1 files changed, 45 insertions, 3 deletions

diff --git a/windows/sleep.c b/windows/sleep.c
index a7e5125e5b..214d6d622a 100644
--- a/windows/sleep.c
+++ b/windows/sleep.c
@@ -25,10 +25,52 @@
  */
 
 #include <windows.h>
+#include <errno.h>
+#include <limits.h>
 
-extern HANDLE hSleepEvent;
+HANDLE waitTimer = NULL;
+
+void init_sleep(void) {
+    waitTimer = CreateWaitableTimer(NULL, TRUE, NULL); 
+}
+
+void deinit_sleep(void) {
+    if (waitTimer != NULL) {
+        CloseHandle(waitTimer);
+        waitTimer = NULL;
+    }
+}
+
+int usleep_impl(__int64 usec) {
+    if (waitTimer == NULL) {
+        errno = EAGAIN;
+        return -1;
+    }
+    if (usec < 0 || usec > LLONG_MAX / 10) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    LARGE_INTEGER ft;
+    ft.QuadPart = -10 * usec; // 100 nanosecond interval, negative value = relative time
+    if (SetWaitableTimer(waitTimer, &ft, 0, NULL, NULL, 0) == 0) {
+        errno = EINVAL;
+        return -1;
+    }
+    if (WaitForSingleObject(waitTimer, INFINITE) != WAIT_OBJECT_0) {
+        errno = EAGAIN;
+        return -1;
+    }
+    return 0;
+}
+
+#ifdef _MSC_VER // mingw and the likes provide their own usleep()
+int usleep(__int64 usec) {
+    return usleep_impl(usec);
+}
+#endif
 
 void msec_sleep(double msec) {
-    ResetEvent(hSleepEvent);
-    WaitForSingleObjectEx(hSleepEvent, msec, FALSE);
+    const double usec = msec * 1000.0;
+    usleep_impl(usec > (double)LLONG_MAX ? LLONG_MAX : (__int64)usec);
 }