start mqtt client (based on paho.mqtt.c), basically works

3rd/paho.mqtt.c/src/MQTTTime.c

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+/*******************************************************************************
+ * Copyright (c) 2020, 2021 IBM Corp. and Ian Craggs
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    https://www.eclipse.org/legal/epl-2.0/
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Ian Craggs - initial implementation
+ *******************************************************************************/
+
+#include "MQTTTime.h"
+#include "StackTrace.h"
+
+#if defined(_WIN32)
+#include <windows.h>
+#else
+#include <unistd.h>
+#include <sys/time.h>
+#endif
+
+void MQTTTime_sleep(ELAPSED_TIME_TYPE milliseconds)
+{
+	FUNC_ENTRY;
+#if defined(_WIN32)
+	Sleep((DWORD)milliseconds);
+#else
+	usleep((useconds_t)(milliseconds*1000));
+#endif
+	FUNC_EXIT;
+}
+
+#if defined(_WIN32)
+START_TIME_TYPE MQTTTime_start_clock(void)
+{
+#if WINVER >= _WIN32_WINNT_VISTA
+	return GetTickCount64();
+#else
+	return GetTickCount();
+#endif
+}
+#elif defined(AIX)
+START_TIME_TYPE MQTTTime_start_clock(void)
+{
+	struct timespec start;
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	return start;
+}
+#else
+START_TIME_TYPE MQTTTime_start_clock(void)
+{
+	struct timeval start;
+	struct timespec start_ts;
+
+	clock_gettime(CLOCK_MONOTONIC, &start_ts);
+	start.tv_sec = start_ts.tv_sec;
+	start.tv_usec = start_ts.tv_nsec / 1000;
+	return start;
+}
+#endif
+START_TIME_TYPE MQTTTime_now(void)
+{
+	return MQTTTime_start_clock();
+}
+
+
+#if defined(_WIN32)
+/*
+ * @param t_new most recent time in milliseconds from GetTickCount()
+ * @param t_old older time in milliseconds from GetTickCount()
+ * @return difference in milliseconds
+ */
+DIFF_TIME_TYPE MQTTTime_difftime(START_TIME_TYPE t_new, START_TIME_TYPE t_old)
+{
+#if WINVER >= _WIN32_WINNT_VISTA
+	return (DIFF_TIME_TYPE)(t_new - t_old);
+#else
+	if (t_old < t_new)       /* check for wrap around condition in GetTickCount */
+		return (DIFF_TIME_TYPE)(t_new - t_old);
+	else
+	    return (DIFF_TIME_TYPE)((0xFFFFFFFFL - t_old) + 1 + t_new);
+#endif
+}
+#elif defined(AIX)
+#define assert(a)
+DIFF_TIME_TYPE MQTTTime_difftime(START_TIME_TYPE t_new, START_TIME_TYPE t_old)
+{
+	struct timespec result;
+
+	ntimersub(t_new, t_old, result);
+	return (DIFF_TIME_TYPE)((result.tv_sec)*1000L + (result.tv_nsec)/1000000L); /* convert to milliseconds */
+}
+#else
+DIFF_TIME_TYPE MQTTTime_difftime(START_TIME_TYPE t_new, START_TIME_TYPE t_old)
+{
+	struct timeval result;
+
+	timersub(&t_new, &t_old, &result);
+	return (DIFF_TIME_TYPE)(((DIFF_TIME_TYPE)result.tv_sec)*1000 + ((DIFF_TIME_TYPE)result.tv_usec)/1000); /* convert to milliseconds */
+}
+#endif
+
+
+ELAPSED_TIME_TYPE MQTTTime_elapsed(START_TIME_TYPE milliseconds)
+{
+	return (ELAPSED_TIME_TYPE)MQTTTime_difftime(MQTTTime_now(), milliseconds);
+}