1 /* 2 * Copyright (C) 2017 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.car.obd2; 18 19 import java.util.function.Function; 20 21 /** 22 * A wrapper over an int[] that offers a moving offset into the array, allowing for sequential 23 * consumption of the array data 24 */ 25 public class IntegerArrayStream { 26 private final int[] mData; 27 private int mIndex; 28 29 public IntegerArrayStream(int[] data) { 30 mData = data; 31 mIndex = 0; 32 } 33 34 public int peek() { 35 return mData[mIndex]; 36 } 37 38 public int consume() { 39 return mData[mIndex++]; 40 } 41 42 public int residualLength() { 43 return mData.length - mIndex; 44 } 45 46 public boolean isEmpty() { 47 return residualLength() == 0; 48 } 49 50 public boolean hasAtLeast(int n) { 51 return residualLength() >= n; 52 } 53 54 public <T> T hasAtLeast(int n, Function<IntegerArrayStream, T> ifTrue) { 55 return hasAtLeast(n, ifTrue, null); 56 } 57 58 public <T> T hasAtLeast( 59 int n, 60 Function<IntegerArrayStream, T> ifTrue, 61 Function<IntegerArrayStream, T> ifFalse) { 62 if (hasAtLeast(n)) { 63 return ifTrue.apply(this); 64 } else { 65 if (ifFalse != null) { 66 return ifFalse.apply(this); 67 } else { 68 return null; 69 } 70 } 71 } 72 73 /** 74 * Validates the content of this stream against an expected data-set. 75 * 76 * <p>If any element of values causes a mismatch, that element will not be consumed and this 77 * method will return false. All elements that do match are consumed from the stream. 78 * 79 * <p>For instance, given a stream with {1,2,3,4}, a call of expect(1,2,5) will consume 1 and 2, 80 * will return false, and stream.peek() will return 3 since it is the first element that did not 81 * match and was not consumed. 82 * 83 * @param values The values to compare this stream's elements against. 84 * @return true if all elements of values match this stream, false otherwise. 85 */ 86 public boolean expect(int... values) { 87 if (!hasAtLeast(values.length)) { 88 return false; 89 } 90 for (int value : values) { 91 if (value != peek()) { 92 return false; 93 } else { 94 consume(); 95 } 96 } 97 return true; 98 } 99 } 100
