Add the 'porttime' source file for Windows

libs/backends/wavesaudio/portmidi/src/porttime/ptwinmm.c

@@ -0,0 +1,71 @@
+/* ptwinmm.c -- portable timer implementation for win32 */
+
+
+#include "porttime.h"
+#include <windows.h>
+#include <mmsystem.h>
+#include <time.h>
+
+
+TIMECAPS caps;
+
+static long time_offset = 0;
+static int time_started_flag = FALSE;
+static long time_resolution;
+static MMRESULT timer_id;
+static PtCallback *time_callback;
+
+void CALLBACK winmm_time_callback(UINT uID, UINT uMsg, DWORD_PTR dwUser, 
+                                  DWORD_PTR dw1, DWORD_PTR dw2)
+{
+    (*time_callback)(Pt_Time(), (void *) dwUser);
+}
+ 
+
+PMEXPORT PtError Pt_Start(int resolution, PtCallback *callback, void *userData)
+{
+    if (time_started_flag) return ptAlreadyStarted;
+    timeBeginPeriod(resolution);
+    time_resolution = resolution;
+    time_offset = timeGetTime();
+    time_started_flag = TRUE;
+    time_callback = callback;
+    if (callback) {
+        timer_id = timeSetEvent(resolution, 1, winmm_time_callback, 
+            (DWORD_PTR) userData, TIME_PERIODIC | TIME_CALLBACK_FUNCTION);
+        if (!timer_id) return ptHostError;
+    }
+    return ptNoError;
+}
+
+
+PMEXPORT PtError Pt_Stop()
+{
+    if (!time_started_flag) return ptAlreadyStopped;
+    if (time_callback && timer_id) {
+        timeKillEvent(timer_id);
+        time_callback = NULL;
+        timer_id = 0;
+    }
+    time_started_flag = FALSE;
+    timeEndPeriod(time_resolution);
+    return ptNoError;
+}
+
+
+PMEXPORT int Pt_Started()
+{
+    return time_started_flag;
+}
+
+
+PMEXPORT PtTimestamp Pt_Time()
+{
+    return timeGetTime() - time_offset;
+}
+
+
+PMEXPORT void Pt_Sleep(int32_t duration)
+{
+    Sleep(duration);
+}