bbgo_origin/pkg/indicator/klinestream.go

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package indicator
import "github.com/c9s/bbgo/pkg/types"
const MaxNumOfKLines = 4_000
//go:generate callbackgen -type KLineStream
type KLineStream struct {
updateCallbacks []func(k types.KLine)
kLines []types.KLine
}
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func (s *KLineStream) Length() int {
return len(s.kLines)
}
func (s *KLineStream) Last(i int) *types.KLine {
l := len(s.kLines)
if i < 0 || l-1-i < 0 {
return nil
}
return &s.kLines[l-1-i]
}
// AddSubscriber adds the subscriber function and push historical data to the subscriber
func (s *KLineStream) AddSubscriber(f func(k types.KLine)) {
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s.OnUpdate(f)
if len(s.kLines) > 0 {
// push historical klines to the subscriber
for _, k := range s.kLines {
f(k)
}
}
}
// KLines creates a KLine stream that pushes the klines to the subscribers
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func KLines(source types.Stream, symbol string, interval types.Interval) *KLineStream {
s := &KLineStream{}
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source.OnKLineClosed(types.KLineWith(symbol, interval, func(k types.KLine) {
s.kLines = append(s.kLines, k)
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s.EmitUpdate(k)
if len(s.kLines) > MaxNumOfKLines {
s.kLines = s.kLines[len(s.kLines)-1-MaxNumOfKLines:]
}
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}))
return s
}