1 /* 2 * Copyright (C) 2020 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.server.location.gnss; 18 19 /** 20 * A simple implementation of exponential backoff. 21 */ 22 class ExponentialBackOff { 23 private static final int MULTIPLIER = 2; 24 private final long mInitIntervalMillis; 25 private final long mMaxIntervalMillis; 26 private long mCurrentIntervalMillis; 27 ExponentialBackOff(long initIntervalMillis, long maxIntervalMillis)28 ExponentialBackOff(long initIntervalMillis, long maxIntervalMillis) { 29 mInitIntervalMillis = initIntervalMillis; 30 mMaxIntervalMillis = maxIntervalMillis; 31 32 mCurrentIntervalMillis = mInitIntervalMillis / MULTIPLIER; 33 } 34 nextBackoffMillis()35 long nextBackoffMillis() { 36 if (mCurrentIntervalMillis > mMaxIntervalMillis) { 37 return mMaxIntervalMillis; 38 } 39 40 mCurrentIntervalMillis *= MULTIPLIER; 41 return mCurrentIntervalMillis; 42 } 43 reset()44 void reset() { 45 mCurrentIntervalMillis = mInitIntervalMillis / MULTIPLIER; 46 } 47 } 48 49