vendor/github.com/codahale/hdrhistogram/window.go


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package hdrhistogram

// A WindowedHistogram combines histograms to provide windowed statistics.
type WindowedHistogram struct {
    idx int
    h   []Histogram
    m   *Histogram

    Current *Histogram
}

// NewWindowed creates a new WindowedHistogram with N underlying histograms with
// the given parameters.
func NewWindowed(n int, minValue, maxValue int64, sigfigs int) *WindowedHistogram {
    w := WindowedHistogram{
        idx: -1,
        h:   make([]Histogram, n),
        m:   New(minValue, maxValue, sigfigs),
    }

    for i := range w.h {
        w.h[i] = *New(minValue, maxValue, sigfigs)
    }
    w.Rotate()

    return &w
}

// Merge returns a histogram which includes the recorded values from all the
// sections of the window.
func (w *WindowedHistogram) Merge() *Histogram {
    w.m.Reset()
    for _, h := range w.h {
        w.m.Merge(&h)
    }
    return w.m
}

// Rotate resets the oldest histogram and rotates it to be used as the current
// histogram.
func (w *WindowedHistogram) Rotate() {
    w.idx++
    w.Current = &w.h[w.idx%len(w.h)]
    w.Current.Reset()
}