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67 lines
1.7 KiB
67 lines
1.7 KiB
//
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// Written by Maxim Khitrov (November 2012)
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//
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package flowrate
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import (
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"math"
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"strconv"
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"time"
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)
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// clockRate is the resolution and precision of clock().
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const clockRate = 20 * time.Millisecond
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// czero is the process start time rounded down to the nearest clockRate
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// increment.
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var czero = time.Duration(time.Now().UnixNano()) / clockRate * clockRate
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// clock returns a low resolution timestamp relative to the process start time.
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func clock() time.Duration {
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return time.Duration(time.Now().UnixNano())/clockRate*clockRate - czero
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}
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// clockToTime converts a clock() timestamp to an absolute time.Time value.
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func clockToTime(c time.Duration) time.Time {
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return time.Unix(0, int64(czero+c))
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}
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// clockRound returns d rounded to the nearest clockRate increment.
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func clockRound(d time.Duration) time.Duration {
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return (d + clockRate>>1) / clockRate * clockRate
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}
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// round returns x rounded to the nearest int64 (non-negative values only).
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func round(x float64) int64 {
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if _, frac := math.Modf(x); frac >= 0.5 {
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return int64(math.Ceil(x))
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}
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return int64(math.Floor(x))
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}
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// Percent represents a percentage in increments of 1/1000th of a percent.
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type Percent uint32
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// percentOf calculates what percent of the total is x.
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func percentOf(x, total float64) Percent {
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if x < 0 || total <= 0 {
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return 0
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} else if p := round(x / total * 1e5); p <= math.MaxUint32 {
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return Percent(p)
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}
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return Percent(math.MaxUint32)
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}
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func (p Percent) Float() float64 {
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return float64(p) * 1e-3
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}
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func (p Percent) String() string {
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var buf [12]byte
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b := strconv.AppendUint(buf[:0], uint64(p)/1000, 10)
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n := len(b)
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b = strconv.AppendUint(b, 1000+uint64(p)%1000, 10)
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b[n] = '.'
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return string(append(b, '%'))
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}
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