func readSystemProcessorPerformanceInformationBuffer()

in sys/windows/ntquery.go [102:133]

27 lines of code
5 McCabe index (conditional complexity)


func readSystemProcessorPerformanceInformationBuffer(b []byte) ([]SystemProcessorPerformanceInformation, error) {
	n := len(b) / sizeofSystemProcessorPerformanceInformation
	r := bytes.NewReader(b)

	rtn := make([]SystemProcessorPerformanceInformation, 0, n)
	for i := 0; i < n; i++ {
		_, err := r.Seek(int64(i*sizeofSystemProcessorPerformanceInformation), io.SeekStart)
		if err != nil {
			return nil, errors.Wrapf(err, "failed to seek to cpuN=%v in buffer", i)
		}

		times := make([]uint64, 3)
		for j := range times {
			err := binary.Read(r, binary.LittleEndian, &times[j])
			if err != nil {
				return nil, errors.Wrapf(err, "failed reading cpu times for cpuN=%v", i)
			}
		}

		idleTime := time.Duration(times[0] * 100)
		kernelTime := time.Duration(times[1] * 100)
		userTime := time.Duration(times[2] * 100)

		rtn = append(rtn, SystemProcessorPerformanceInformation{
			IdleTime:   idleTime,
			KernelTime: kernelTime - idleTime, // Subtract out idle time from kernel time.
			UserTime:   userTime,
		})
	}

	return rtn, nil
}