mirror of https://github.com/jetkvm/kvm.git
48 lines
1.6 KiB
Go
48 lines
1.6 KiB
Go
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
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// SPDX-License-Identifier: MIT
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// Package ntp provides conversion methods between time.Time and NTP timestamps
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// stored in uint64
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package ntp
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import (
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"time"
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)
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// ToNTP converts a time.Time oboject to an uint64 NTP timestamp.
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func ToNTP(t time.Time) uint64 {
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// seconds since 1st January 1900
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s := (float64(t.UnixNano()) / 1000000000) + 2208988800
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// higher 32 bits are the integer part, lower 32 bits are the fractional part
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integerPart := uint32(s)
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fractionalPart := uint32((s - float64(integerPart)) * 0xFFFFFFFF)
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return uint64(integerPart)<<32 | uint64(fractionalPart) //nolint:gosec // G115
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}
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// ToNTP32 converts a time.Time object to a uint32 NTP timestamp.
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func ToNTP32(t time.Time) uint32 {
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return uint32(ToNTP(t) >> 16) //nolint:gosec // G115
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}
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// ToTime converts a uint64 NTP timestamps to a time.Time object.
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func ToTime(t uint64) time.Time {
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seconds := (t & 0xFFFFFFFF00000000) >> 32
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fractional := float64(t&0x00000000FFFFFFFF) / float64(0xFFFFFFFF)
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//nolint:gosec // G115
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d := time.Duration(seconds)*time.Second + time.Duration(fractional*1e9)*time.Nanosecond
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return time.Unix(0, 0).Add(-2208988800 * time.Second).Add(d)
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}
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// ToTime32 converts a uint32 NTP timestamp to a time.Time object, using the
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// highest 16 bit of the reference to recover the lost bits. The low 16 bits are
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// not recovered.
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func ToTime32(t uint32, reference time.Time) time.Time {
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referenceNTP := ToNTP(reference) & 0xFFFF000000000000
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tu64 := ((uint64(t) << 16) & 0x0000FFFFFFFF0000) | referenceNTP
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return ToTime(tu64)
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}
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