Add compatibility shim for MSVC

src/msvc/usleep.cpp

@@ -0,0 +1,93 @@
+/*
+ * avrdude - A Downloader/Uploader for AVR device programmers
+ * Copyright (C) 2018 Marius Greuel
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "unistd.h"
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <mmsystem.h>
+#pragma comment(lib, "winmm.lib")
+
+class MicroSleep
+{
+public:
+    MicroSleep()
+    {
+        if (::timeBeginPeriod(timerPeriod) == TIMERR_NOERROR)
+        {
+            m_resetTimerPeriod = true;
+        }
+    }
+
+    ~MicroSleep()
+    {
+        if (m_resetTimerPeriod)
+        {
+            ::timeEndPeriod(timerPeriod);
+        }
+    }
+
+    int Sleep(DWORD us)
+    {
+        if (us == 0)
+        {
+            return 0;
+        }
+
+        LARGE_INTEGER frequency{};
+        if (QueryPerformanceFrequency(&frequency))
+        {
+            LARGE_INTEGER start{};
+            QueryPerformanceCounter(&start);
+
+            if (us > 10000)
+            {
+                ::Sleep((us - 5000) / 1000);
+            }
+
+            LARGE_INTEGER end{};
+            end.QuadPart = start.QuadPart + (frequency.QuadPart * us / 1000000);
+
+            while (true)
+            {
+                LARGE_INTEGER current;
+                QueryPerformanceCounter(&current);
+                if (current.QuadPart >= end.QuadPart)
+                {
+                    break;
+                }
+            }
+        }
+        else
+        {
+            ::Sleep((us / 1000) + 1);
+        }
+
+        return 0;
+    }
+
+private:
+    static const UINT timerPeriod = 1; // 1ms
+    bool m_resetTimerPeriod = false;
+};
+
+int usleep(unsigned int us)
+{
+    static MicroSleep microSleep;
+    return microSleep.Sleep(us);
+}