1 /* 2 * Copyright 2024, Google LLC 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * Neither the name of Google LLC nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 package com.android.tools.smali.util; 32 33 import java.util.ArrayList; 34 import java.util.Collection; 35 import java.util.Iterator; 36 import java.util.List; 37 import java.util.Objects; 38 import java.util.function.Predicate; 39 40 public final class IteratorUtils { 41 getLast(Iterator<T> iterator)42 public static <T extends Object> T getLast(Iterator<T> iterator) { 43 while (true) { 44 T current = iterator.next(); 45 if (!iterator.hasNext()) { 46 return current; 47 } 48 } 49 } 50 filter( Iterable<T> unfiltered, Predicate<? super T> retainIfTrue)51 public static <T extends Object> AbstractIterator<T> filter( 52 Iterable<T> unfiltered, Predicate<? super T> retainIfTrue) { 53 return filter(unfiltered.iterator(), retainIfTrue); 54 } 55 filter( Iterator<T> unfiltered, Predicate<? super T> retainIfTrue)56 public static <T extends Object> AbstractIterator<T> filter( 57 Iterator<T> unfiltered, Predicate<? super T> retainIfTrue) { 58 return new AbstractIterator<T>() { 59 @Override 60 protected T computeNext() { 61 while (unfiltered.hasNext()) { 62 T next = unfiltered.next(); 63 if (retainIfTrue.test(next)) { 64 return next; 65 } 66 } 67 return endOfData(); 68 } 69 }; 70 } 71 72 public static <T extends Object> List<T> toList(Iterable<T> iterable) { 73 return toList(iterable.iterator()); 74 } 75 76 public static <T extends Object> List<T> toList(Iterator<T> iterator) { 77 ArrayList<T> list = new ArrayList<T>(); 78 while (iterator.hasNext()) { 79 list.add(iterator.next()); 80 } 81 return list; 82 } 83 84 public static <T extends Object> void addAll(Collection<T> collection, Iterator<T> iterator) { 85 while (iterator.hasNext()) { 86 collection.add(iterator.next()); 87 } 88 } 89 90 public static boolean elementsEqual(Iterator<?> iterator1, Iterator<?> iterator2) { 91 while (iterator1.hasNext()) { 92 if (!iterator2.hasNext()) { 93 return false; 94 } 95 Object o1 = iterator1.next(); 96 Object o2 = iterator2.next(); 97 if (!Objects.equals(o1, o2)) { 98 return false; 99 } 100 } 101 return !iterator2.hasNext(); 102 } 103 104 public static int size(Iterable<?> iterable) { 105 Iterator<?> iterator = iterable.iterator(); 106 int count = 0; 107 while (iterator.hasNext()) { 108 count++; 109 iterator.next(); 110 } 111 return count; 112 } 113 } 114