Move Windows timer utility functions from PA backend into libpbd

libs/pbd/windows_timer_utils.cc

@@ -0,0 +1,184 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "pbd/windows_timer_utils.h"
+
+#include <windows.h>
+#include <mmsystem.h>
+
+#include "pbd/compose.h"
+#include "pbd/debug.h"
+
+#define DEBUG_TIMING(msg) DEBUG_TRACE (PBD::DEBUG::Timing, msg);
+
+namespace {
+
+UINT&
+old_timer_resolution ()
+{
+	static UINT timer_res_ms = 0;
+	return timer_res_ms;
+}
+
+} // anon namespace
+
+namespace PBD {
+
+namespace MMTIMERS {
+
+bool
+set_min_resolution ()
+{
+	TIMECAPS caps;
+
+	if (timeGetDevCaps (&caps, sizeof(TIMECAPS)) != TIMERR_NOERROR) {
+		DEBUG_TIMING ("Could not get timer device capabilities.\n");
+		return false;
+	}
+	return set_resolution(caps.wPeriodMin);
+}
+
+bool
+set_resolution (uint32_t timer_resolution_ms)
+{
+	TIMECAPS caps;
+
+	if (timeGetDevCaps (&caps, sizeof(TIMECAPS)) != TIMERR_NOERROR) {
+		DEBUG_TIMING ("Could not get timer device capabilities.\n");
+		return false;
+	}
+
+	UINT old_timer_res = caps.wPeriodMin;
+
+	if (timeBeginPeriod(timer_resolution_ms) != TIMERR_NOERROR) {
+		DEBUG_TIMING(
+		    string_compose("Could not set minimum timer resolution to %1(ms)\n",
+		                   timer_resolution_ms));
+		return false;
+	}
+
+	old_timer_resolution () = old_timer_res;
+
+	DEBUG_TIMING (string_compose ("Multimedia timer resolution set to %1(ms)\n",
+	                              caps.wPeriodMin));
+	return true;
+}
+
+bool
+get_resolution (uint32_t& timer_resolution_ms)
+{
+	TIMECAPS caps;
+
+	if (timeGetDevCaps(&caps, sizeof(TIMECAPS)) != TIMERR_NOERROR) {
+		DEBUG_TIMING ("Could not get timer device capabilities.\n");
+		return false;
+	}
+	timer_resolution_ms = caps.wPeriodMin;
+	return true;
+}
+
+bool
+reset_resolution ()
+{
+	if (old_timer_resolution ()) {
+		if (timeEndPeriod (old_timer_resolution ()) != TIMERR_NOERROR) {
+			DEBUG_TIMING ("Could not reset timer resolution.\n");
+			return false;
+		}
+	}
+
+	DEBUG_TIMING (string_compose ("Multimedia timer resolution set to %1(ms)\n",
+	                              old_timer_resolution ()));
+
+	return true;
+}
+
+} // namespace MMTIMERS
+
+namespace {
+
+bool&
+qpc_frequency_success ()
+{
+	static bool success = false;
+	return success;
+}
+
+LARGE_INTEGER
+qpc_frequency ()
+{
+	LARGE_INTEGER freq;
+	if (QueryPerformanceFrequency(&freq) == 0) {
+		DEBUG_TIMING ("Failed to determine frequency of QPC\n");
+		qpc_frequency_success() = false;
+	} else {
+		qpc_frequency_success() = true;
+	}
+
+	return freq;
+}
+
+LARGE_INTEGER
+qpc_frequency_cached ()
+{
+	static LARGE_INTEGER frequency = qpc_frequency ();
+	return frequency;
+}
+
+} // anon namespace
+
+namespace QPC {
+
+bool
+get_timer_valid ()
+{
+	// setup caching the timer frequency
+	qpc_frequency_cached ();
+	return qpc_frequency_success ();
+}
+
+int64_t
+get_microseconds ()
+{
+	LARGE_INTEGER current_val;
+
+	if (qpc_frequency_success()) {
+		// MS docs say this will always succeed for systems >= XP but it may
+		// not return a monotonic value with non-invariant TSC's etc
+		if (QueryPerformanceCounter(&current_val) != 0) {
+			return (int64_t)(((double)current_val.QuadPart) /
+			                 ((double)qpc_frequency_cached().QuadPart) * 1000000.0);
+		}
+	}
+	DEBUG_TIMING ("Could not get QPC timer\n");
+	return -1;
+}
+
+} // namespace QPC
+
+int64_t
+get_microseconds ()
+{
+	if (qpc_frequency_success()) {
+		return QPC::get_microseconds ();
+	}
+	// For XP systems that don't support a high-res performance counter
+	return g_get_monotonic_time ();
+}
+
+} // namespace PBD