Very basic stuff: CAN driver iface, linked list, system clock interface, tests

libuavcan/include/uavcan/system_clock.hpp

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+/*
+ * System clock driver interface.
+ * Copyright (C) 2013 Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#pragma once
+
+#include <cstdint>
+
+namespace uavcan
+{
+/**
+ * System clock interface - monotonic and UTC.
+ * Note that this library uses microseconds for all time related values (timestamps, deadlines, delays),
+ * if not explicitly specified otherwise.
+ * All time values are represented as 64-bit integers.
+ */
+class ISystemClock
+{
+    /**
+     * Monototic system clock in microseconds.
+     * This shall never jump during UTC timestamp adjustments; the base time is irrelevant.
+     * On POSIX systems use clock_gettime() with CLOCK_MONOTONIC.
+     */
+    virtual uint64_t getMonotonicMicroseconds() const = 0;
+
+    /**
+     * UTC clock in microseconds.
+     * This can jump when the UTC timestamp is being adjusted.
+     * Return 0 if the UTC time is not available yet (e.g. the device just started up with no battery clock).
+     * On POSIX systems use gettimeofday().
+     */
+    virtual uint64_t getUtcMicroseconds() const = 0;
+
+    /**
+     * Set the UTC system clock.
+     * @param [in] timestamp New UTC timestamp. Avoid when possible.
+     * @param [in] offset    Current UTC time error. More precise than just timestamp, use it if possible.
+     * For POSIX refer to adjtime(), settimeofday().
+     */
+    virtual void adjustUtcMicroseconds(uint64_t new_timestamp_usec, int64_t offset_usec) = 0;
+};
+
+}