214 lines
8 KiB
Kotlin
214 lines
8 KiB
Kotlin
package info.nightscout.androidaps.utils
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import android.os.SystemClock
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import javax.inject.Singleton
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import javax.inject.Inject
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import info.nightscout.androidaps.logging.AAPSLogger
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import java.lang.Exception
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import java.net.DatagramPacket
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import java.net.DatagramSocket
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import java.net.InetAddress
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/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/ /**
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* {@hide}
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*
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*
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* Simple SNTP client class for retrieving network time.
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*
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*
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* Sample usage:
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* <pre>SntpClient client = new SntpClient();
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* if (client.requestTime("time.foo.com")) {
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* long now = client.getNtpTime() + SystemClock.elapsedRealtime() - client.getNtpTimeReference();
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* }
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</pre> *
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*/
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@Singleton
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class SntpClient @Inject constructor(
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private val aapsLogger: AAPSLogger,
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private val dateUtil: DateUtil
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) {
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companion object {
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//private final int REFERENCE_TIME_OFFSET = 16;
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private const val ORIGINATE_TIME_OFFSET = 24
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private const val RECEIVE_TIME_OFFSET = 32
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private const val TRANSMIT_TIME_OFFSET = 40
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private const val NTP_PACKET_SIZE = 48
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private const val NTP_PORT = 123
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private const val NTP_MODE_CLIENT = 3
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private const val NTP_VERSION = 3
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// Number of seconds between Jan 1, 1900 and Jan 1, 1970
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// 70 years plus 17 leap days
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private const val OFFSET_1900_TO_1970 = (365L * 70L + 17L) * 24L * 60L * 60L
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}
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/**
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* Returns the time computed from the NTP transaction.
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*
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* @return time value computed from NTP server response.
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*/
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// system time computed from NTP server response
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private var ntpTime: Long = 0
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/**
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* Returns the reference clock value (value of SystemClock.elapsedRealtime())
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* corresponding to the NTP time.
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*
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* @return reference clock corresponding to the NTP time.
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*/
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// value of SystemClock.elapsedRealtime() corresponding to mNtpTime
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private var ntpTimeReference: Long = 0
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/**
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* Returns the round trip time of the NTP transaction
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*
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* @return round trip time in milliseconds.
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*/
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// round trip time in milliseconds
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private var roundTripTime: Long = 0
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abstract class Callback : Runnable {
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var networkConnected = false
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var success = false
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var time: Long = 0
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}
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@Synchronized fun ntpTime(callback: Callback, isConnected: Boolean) {
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callback.networkConnected = isConnected
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if (callback.networkConnected) {
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Thread { doNtpTime(callback) }.start()
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} else {
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callback.run()
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}
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}
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fun doNtpTime(callback: Callback) {
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aapsLogger.debug("Time detection started")
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callback.success = requestTime("time.google.com", 5000)
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callback.time = ntpTime + SystemClock.elapsedRealtime() - ntpTimeReference
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aapsLogger.debug("Time detection ended: " + callback.success + " " + dateUtil.dateAndTimeString(ntpTime))
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callback.run()
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}
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/**
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* Sends an SNTP request to the given host and processes the response.
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*
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* @param host host name of the server.
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* @param timeout network timeout in milliseconds.
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* @return true if the transaction was successful.
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*/
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@Suppress("SameParameterValue")
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@Synchronized private fun requestTime(host: String, timeout: Int): Boolean {
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try {
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val socket = DatagramSocket()
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socket.soTimeout = timeout
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val address = InetAddress.getByName(host)
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val buffer = ByteArray(NTP_PACKET_SIZE)
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val request = DatagramPacket(buffer, buffer.size, address, NTP_PORT)
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// set mode = 3 (client) and version = 3
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// mode is in low 3 bits of first byte
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// version is in bits 3-5 of first byte
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buffer[0] = (NTP_MODE_CLIENT or (NTP_VERSION shl 3)).toByte()
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// get current time and write it to the request packet
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val requestTime = System.currentTimeMillis()
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val requestTicks = SystemClock.elapsedRealtime()
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writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET, requestTime)
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socket.send(request)
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// read the response
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val response = DatagramPacket(buffer, buffer.size)
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socket.receive(response)
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val responseTicks = SystemClock.elapsedRealtime()
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val responseTime = requestTime + (responseTicks - requestTicks)
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socket.close()
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// extract the results
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val originateTime = readTimeStamp(buffer, ORIGINATE_TIME_OFFSET)
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val receiveTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET)
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val transmitTime = readTimeStamp(buffer, TRANSMIT_TIME_OFFSET)
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val roundTripTime = responseTicks - requestTicks - (transmitTime - receiveTime)
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val clockOffset = (receiveTime - originateTime + (transmitTime - responseTime)) / 2
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// save our results - use the times on this side of the network latency
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// (response rather than request time)
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ntpTime = responseTime + clockOffset
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ntpTimeReference = responseTicks
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this.roundTripTime = roundTripTime
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} catch (e: Exception) {
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aapsLogger.debug("request time failed: $e")
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return false
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}
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return true
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}
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/**
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* Reads an unsigned 32 bit big endian number from the given offset in the buffer.
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*/
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private fun read32(buffer: ByteArray, offset: Int): Long {
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val b0 = buffer[offset]
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val b1 = buffer[offset + 1]
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val b2 = buffer[offset + 2]
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val b3 = buffer[offset + 3]
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// convert signed bytes to unsigned values
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val i0 = if (b0.toInt() and 0x80 == 0x80) (b0.toInt() and 0x7F) + 0x80 else b0.toInt()
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val i1 = if (b1.toInt() and 0x80 == 0x80) (b1.toInt() and 0x7F) + 0x80 else b1.toInt()
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val i2 = if (b2.toInt() and 0x80 == 0x80) (b2.toInt() and 0x7F) + 0x80 else b2.toInt()
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val i3 = if (b3.toInt() and 0x80 == 0x80) (b3.toInt() and 0x7F) + 0x80 else b3.toInt()
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return (i0.toLong() shl 24) + (i1.toLong() shl 16) + (i2.toLong() shl 8) + i3.toLong()
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}
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/**
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* Reads the NTP time stamp at the given offset in the buffer and returns
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* it as a system time (milliseconds since January 1, 1970).
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*/
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private fun readTimeStamp(buffer: ByteArray, offset: Int): Long {
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val seconds = read32(buffer, offset)
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val fraction = read32(buffer, offset + 4)
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return (seconds - OFFSET_1900_TO_1970) * 1000 + fraction * 1000L / 0x100000000L
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}
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/**
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* Writes system time (milliseconds since January 1, 1970) as an NTP time stamp
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* at the given offset in the buffer.
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*/
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@Suppress("SameParameterValue")
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private fun writeTimeStamp(buffer: ByteArray, offsetParam: Int, time: Long) {
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var offset = offsetParam
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var seconds = time / 1000L
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val milliseconds = time - seconds * 1000L
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seconds += OFFSET_1900_TO_1970
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// write seconds in big endian format
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buffer[offset++] = (seconds shr 24).toByte()
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buffer[offset++] = (seconds shr 16).toByte()
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buffer[offset++] = (seconds shr 8).toByte()
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buffer[offset++] = (seconds shr 0).toByte()
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val fraction = milliseconds * 0x100000000L / 1000L
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// write fraction in big endian format
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buffer[offset++] = (fraction shr 24).toByte()
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buffer[offset++] = (fraction shr 16).toByte()
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buffer[offset++] = (fraction shr 8).toByte()
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// low order bits should be random data
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buffer[offset] = (Math.random() * 255.0).toInt().toByte()
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}
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} |