results.go

package tlsping

import (
	"fmt"
	"math"
)

// PingResult contains summary statistics of the measured connection
// times
type PingResult struct {
	// Target host name
	Host string

	// IP Address of the host used for these measurements
	IPAddr string

	// Address of the target, in the form hostname:port
	Address string

	// Number of measurements summarized in this result
	Count int

	// Minimum and maximum observed connection times, in seconds
	Min, Max float64

	// Average and standard deviation of the observed connection
	// times, in seconds
	Avg, Std float64
}

// setSummaryStats sets the summary stats passed as arguments to the ping
// result
func (r *PingResult) setSummaryStats(count int, min, max, avg, std float64) {
	r.Count = count
	r.Min, r.Max = min, max
	r.Avg, r.Std = avg, std
}

// summarize summarizes the measurements of time durations given as
// argument. The result argument is populated with summary statistics
// of the durations. The argument values and the returned values are understood
// in seconds
func summarize(durations []float64) (count int, min, max, avg, std float64) {
	count = len(durations)
	min, max = math.MaxFloat64, math.SmallestNonzeroFloat64
	sum := float64(0)
	for _, d := range durations {
		sum += d
		if d < min {
			min = d
		}
		if d > max {
			max = d
		}
	}
	n := float64(count)
	avg = sum / n
	std = float64(0)
	for _, d := range durations {
		dev := d - avg
		std += dev * dev
	}
	std = math.Sqrt(std / n)
	return
}

func (r *PingResult) MinStr() string {
	return secsToString(r.Min)
}

func (r *PingResult) MaxStr() string {
	return secsToString(r.Max)
}

func (r *PingResult) AvgStr() string {
	return secsToString(r.Avg)
}

func (r *PingResult) StdStr() string {
	return secsToString(r.Std)
}

func secsToString(secs float64) string {
	if secs >= 1.0 {
		// unit is seconds
		return fmt.Sprintf("%.2fs", secs)
	}
	secs = secs * 1000.0
	if secs >= 1.0 {
		// unit is milliseconds
		return fmt.Sprintf("%.2fms", secs)
	}
	secs = secs * 1000.0
	if secs >= 1.0 {
		// unit is µ seconds
		return fmt.Sprintf("%.2fµs", secs)
	}
	// unit is nano seconds
	secs = secs * 1000.0
	return fmt.Sprintf("%.2fns", secs)
}