95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
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package channel
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import (
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"time"
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)
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// GroupByTime groups all incoming values from source using the grouper function
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// and sends them to the returned channel after the given amount of time.
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// This can useful for summing or averaging values from a channel on a fixed interval
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func GroupByTime[T, G any](source <-chan T, duration time.Duration, grouper func(current G, value T) G) <-chan G {
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out := make(chan G, cap(source))
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go func() {
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defer close(out)
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ticker := time.NewTicker(duration)
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defer ticker.Stop()
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current := *new(G)
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changed := false
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for {
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select {
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case value, ok := <-source:
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if !ok {
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if changed {
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out <- current
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}
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return
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}
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current = grouper(current, value)
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changed = true
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case <-ticker.C:
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group := current
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out <- group
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current = *new(G)
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changed = false
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}
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}
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}()
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return out
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}
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// GroupByAmount groups all incoming values from source using the grouper function
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// and sends them to the returned channel after the given amount of values were grouped.
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// This can useful for summing or averaging values from a channel for a given amount of values
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func GroupByAmount[T, G any](source <-chan T, amount int, grouper func(current G, value T) G) <-chan G {
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out := make(chan G, cap(source))
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go func() {
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defer close(out)
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current := *new(G)
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currentAmount := 0
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for value := range source {
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currentAmount++
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current = grouper(current, value)
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if currentAmount%amount == 0 {
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group := current
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out <- group
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current = *new(G)
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}
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}
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}()
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return out
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}
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// GroupByValue groups all incoming values from source using the grouper function
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// and sends them to the returned channel after valueFunc returns true for a given value.
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// This can useful for summing or averaging values from a channel for a given amount of values
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func GroupByValue[T, G any](source <-chan T, valueFunc func(T) bool, grouper func(current G, value T) G) <-chan G {
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out := make(chan G, cap(source))
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go func() {
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defer close(out)
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current := *new(G)
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currentAmount := 0
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for value := range source {
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currentAmount++
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current = grouper(current, value)
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if valueFunc(value) {
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group := current
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out <- group
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current = *new(G)
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}
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}
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}()
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return out
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}
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