absent.go

// Copyright (c) 2018 Uber Technologies, Inc.
//
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// The above copyright notice and this permission notice shall be included in
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// THE SOFTWARE.

package linear

import (
	"math"

	"github.com/m3db/m3/src/query/executor/transform"
)

// AbsentType returns a timeseries with all NaNs if the timeseries passed in has any non NaNs,
// and returns a timeseries with the value 1 if the timeseries passed in has no elements
const AbsentType = "absent"

// NewAbsentOp creates a new base linear transform with an absent node
func NewAbsentOp() BaseOp {
	return BaseOp{
		operatorType: AbsentType,
		processorFn:  newAbsentNode,
	}
}

func newAbsentNode(op BaseOp, controller *transform.Controller) Processor {
	return &absentNode{
		op:         op,
		controller: controller,
	}
}

type absentNode struct {
	op         BaseOp
	controller *transform.Controller
}

func (c *absentNode) Process(values []float64) []float64 {
	num := 1.0
	if !allNaNs(values) {
		num = math.NaN()
	}

	for i := range values {
		values[i] = num
	}
	return values
}

func allNaNs(vals []float64) bool {
	for _, i := range vals {
		if !math.IsNaN(i) {
			return false
		}
	}
	return true
}