tai64n.go

// SPDX-License-Identifier: MPL-2.0
/*
 * Copyright (C) 2024 The Noisy Sockets Authors.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Portions of this file are based on code originally from wireguard-go,
 *
 * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package tai64n

import (
	"bytes"
	"encoding/binary"
	"time"
)

const (
	TimestampSize = 12
	base          = uint64(0x400000000000000a)
	whitenerMask  = uint32(0x1000000 - 1)
)

type Timestamp [TimestampSize]byte

func stamp(t time.Time) Timestamp {
	var tai64n Timestamp
	secs := base + uint64(t.Unix())
	nano := uint32(t.Nanosecond()) &^ whitenerMask
	binary.BigEndian.PutUint64(tai64n[:], secs)
	binary.BigEndian.PutUint32(tai64n[8:], nano)
	return tai64n
}

func Now() Timestamp {
	return stamp(time.Now())
}

func (t1 Timestamp) After(t2 Timestamp) bool {
	return bytes.Compare(t1[:], t2[:]) > 0
}

func (t Timestamp) String() string {
	return time.Unix(int64(binary.BigEndian.Uint64(t[:8])-base), int64(binary.BigEndian.Uint32(t[8:12]))).String()
}