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.

windows/init.c

@@ -26,12 +26,10 @@
 
 #include <stdlib.h>
 #include <stdio.h>
-#include <windows.h>
-
-HANDLE hSleepEvent = NULL;
+#include "sleep.h"
 
 void init() {
-    hSleepEvent = CreateEvent(NULL, TRUE, FALSE, FALSE);
+    init_sleep();
 #ifdef __MINGW32__
     putenv("PRINTF_EXPONENT_DIGITS=2");
 #else
@@ -40,7 +38,5 @@ void init() {
 }
 
 void deinit() {
-    if (hSleepEvent != NULL) {
-        CloseHandle(hSleepEvent);
-    }
+    deinit_sleep();
 }

windows/mpconfigport.h

@@ -162,9 +162,7 @@ extern const struct _mp_obj_module_t mp_module_time;
 
 #include "realpath.h"
 #include "init.h"
-
-// sleep for given number of milliseconds
-void msec_sleep(double msec);
+#include "sleep.h"
 
 // MSVC specifics
 #ifdef _MSC_VER

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);
 }

windows/sleep.h

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+void init_sleep(void);
+void deinit_sleep(void);
+void msec_sleep(double msec);
+#ifdef _MSC_VER
+int usleep(__int64 usec);
+#endif