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Timestamps and Time Differences

libxr_time.hpp defines the microsecond and millisecond timestamps MicrosecondTimestamp and MillisecondTimestamp and their Duration. The current time comes from GetMicroseconds() / GetMilliseconds() of Timebase.

MicrosecondTimestamp​

class MicrosecondTimestamp {
 public:
  MicrosecondTimestamp();
  MicrosecondTimestamp(uint64_t microsecond);
  operator uint64_t() const;

  class Duration {
   public:
    Duration(uint64_t diff);
    operator uint64_t() const;
    double ToSecond() const;
    float ToSecondf() const;
    uint64_t ToMicrosecond() const;
    uint32_t ToMillisecond() const;
  };

  Duration operator-(const MicrosecondTimestamp& old) const;
  MicrosecondTimestamp& operator=(const MicrosecondTimestamp& other);
};
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Represents a microsecond-level timestamp. Supports implicit conversion to uint64_t and can be used to compute time differences.

Duration​

MicrosecondTimestamp::Duration represents the time difference between two MicrosecondTimestamp instances, in microseconds. Supports conversion to seconds and milliseconds.

MillisecondTimestamp​

class MillisecondTimestamp {
 public:
  MillisecondTimestamp();
  MillisecondTimestamp(uint32_t millisecond);
  operator uint32_t() const;

  class Duration {
   public:
    Duration(uint32_t diff);
    operator uint32_t() const;
    double ToSecond() const;
    float ToSecondf() const;
    uint32_t ToMillisecond() const;
    uint64_t ToMicrosecond() const;
  };

  Duration operator-(const MillisecondTimestamp& old) const;
};
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Represents a millisecond-level timestamp. Supports implicit conversion to uint32_t and can be used to compute time differences.

Duration​

MillisecondTimestamp::Duration represents the time difference between two MillisecondTimestamp instances, in milliseconds. Supports conversion to seconds and microseconds.

Overflow Handling​

When the newer timestamp is smaller, subtraction assumes one wrap-around; a difference beyond the wrap limit fails an assertion in Debug builds.

The wrap limits live in the LibXR::Detail namespace:

uint64_t TimebaseMaxValidUs();
uint32_t TimebaseMaxValidMs();
void ConfigureTimebaseWrapRange(uint64_t max_valid_us,
                                uint32_t max_valid_ms) noexcept;

Each platform Timebase backend calls Timebase::ConfigureWrapRange() in its constructor, which forwards to Detail::ConfigureTimebaseWrapRange(); without it the limits are UINT64_MAX / UINT32_MAX. Application code normally does not call the Detail functions.