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