74 lines
1.3 KiB
Go
74 lines
1.3 KiB
Go
package utilities
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import (
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"math"
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"math/rand/v2"
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"time"
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)
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var (
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ApplyJitter = DefaultApplyJitter
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)
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const (
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maxInt64 = math.MaxInt64
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minInt64 = math.MinInt64
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)
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func satAdd(a, b int64) int64 {
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switch {
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case b > 0 && a > maxInt64-b:
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return maxInt64
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case b < 0 && a < minInt64-b:
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return minInt64
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default:
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return a + b
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}
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}
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func satSub(a, b int64) int64 {
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switch {
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case b > 0 && a < minInt64+b:
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return minInt64
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case b < 0 && a > maxInt64+b:
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return maxInt64
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default:
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return a - b
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}
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}
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func DefaultApplyJitter(pauseDuration time.Duration, jitter time.Duration) time.Duration {
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switch {
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case pauseDuration <= 0:
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return 0
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case jitter == 0:
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return pauseDuration
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case jitter < 0:
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jitter = -jitter
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case jitter > pauseDuration:
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pauseDuration, jitter = jitter, pauseDuration
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}
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min := satSub(pauseDuration.Nanoseconds(), jitter.Nanoseconds())
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if min < 0 {
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min = 0
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}
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max := satAdd(pauseDuration.Nanoseconds(), jitter.Nanoseconds())
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if max <= min {
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return time.Duration(min)
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}
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var maxExcl int64
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if max == math.MaxInt64 {
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span := max - min
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if span == math.MaxInt64 {
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return time.Duration(rand.Int64N(math.MaxInt64) + min)
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}
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n := rand.Int64N(span + 1)
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return time.Duration(min + n)
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}
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maxExcl = max + 1
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return time.Duration(min + rand.Int64N(maxExcl-min))
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}
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