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56 lines
2.2 KiB
Go
56 lines
2.2 KiB
Go
// Copyright 2021 Molecula Corp. All rights reserved.
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package pilosa
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// util.go: a place for generic, reusable utilities.
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import (
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"reflect"
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"time"
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)
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// LeftShifted16MaxContainerKey is 0xffffffffffff0000. It is similar
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// to the roaring.maxContainerKey 0x0000ffffffffffff, but
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// shifted 16 bits to the left so its domain is the full [0, 2^64) bit space.
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// It is used to match the semantics of the roaring.OffsetRange() API.
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// This is the maximum endx value for Tx.OffsetRange(), because the lowbits,
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// as in the roaring.OffsetRange(), are not allowed to be set.
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// It is used in Tx.RoaringBitamp() to obtain the full contents of a fragment
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// from a call from tx.OffsetRange() by requesting [0, LeftShifted16MaxContainerKey)
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// with an offset of 0.
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const LeftShifted16MaxContainerKey = uint64(0xffffffffffff0000) // or math.MaxUint64 - (1<<16 - 1), or 18446744073709486080
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// NilInside checks if the provided iface is nil or
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// contains a nil pointer, slice, array, map, or channel.
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func NilInside(iface interface{}) bool {
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if iface == nil {
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return true
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}
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switch reflect.TypeOf(iface).Kind() {
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case reflect.Ptr, reflect.Slice, reflect.Array, reflect.Map, reflect.Chan:
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return reflect.ValueOf(iface).IsNil()
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}
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return false
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}
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//////////////////////////////////
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// helper utility functions
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func highbits(v uint64) uint64 { return v >> 16 }
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func lowbits(v uint64) uint16 { return uint16(v & 0xFFFF) }
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// GetLoopProgress returns the estimated remaining time to iterate through some
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// items as well as the loop completion percentage with the following
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// parameters:
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// the start time, the current time, the iteration, and the number of items
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func GetLoopProgress(start time.Time, now time.Time, iteration uint, total uint) (remaining time.Duration, pctDone float64) {
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itemsLeft := total - (iteration + 1)
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avgItemTime := float64(now.Sub(start)) / float64(iteration+1)
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pctDone = (float64(iteration+1) / float64(total)) * 100
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return time.Duration(avgItemTime * float64(itemsLeft)), pctDone
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}
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// FormatTimestampNano returns the string representation of a timestamp given:
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// an epoch value, base, and time unit
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func FormatTimestampNano(value, base int64, timeUnit string) string {
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return time.Unix(0, (value+base)*TimeUnitNanos(timeUnit)).UTC().Format(time.RFC3339Nano)
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}
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