Timebase

LibXR::Timebase provides the common timebase contract used by LibXR to access microsecond and millisecond timestamps. It is the foundation for timeout handling, periodic scheduling, and timestamped middleware paths such as Topic and USB-related timing.

Interface Definition

class Timebase {
public:
  Timebase() = default;
  Timebase(const Timebase&) = delete;
  Timebase& operator=(const Timebase&) = delete;

  static MicrosecondTimestamp GetMicroseconds();
  static MillisecondTimestamp GetMilliseconds();
  [[nodiscard]] static bool IsReady() noexcept;
  static void DelayMicroseconds(uint32_t us);

protected:
  static void SetReady(bool ready = true) noexcept;
  static void ConfigureWrapRange(uint64_t max_valid_us,
                                 uint32_t max_valid_ms) noexcept;
  [[nodiscard]] static uint64_t GetConfiguredWrapRangeUs() noexcept;
  [[nodiscard]] static uint32_t GetConfiguredWrapRangeMs() noexcept;
};

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Usage Notes

• GetMicroseconds() and GetMilliseconds() return MicrosecondTimestamp and MillisecondTimestamp, defined in core/libxr_time.hpp.
• Timestamp subtraction is wrap-aware. Backend code can set the valid wrap range with ConfigureWrapRange(...).
• IsReady() reports whether the active platform backend has finished initialization. PlatformInit() on FreeRTOS and ThreadX uses it to check the timebase, so board code constructs the timebase object before calling PlatformInit(); see Platform initialization.
• DelayMicroseconds() provides a small busy-wait helper built on the microsecond timebase.
• Platform backends such as LinuxTimebase, STM32Timebase, CH32Timebase, and ESP32Timebase typically initialize hardware state in their constructors, call ConfigureWrapRange(...), then mark the backend ready with SetReady().
• The static getters GetMicroseconds() and GetMilliseconds() are implemented in each platform's timebase source file.