1 /*
2  * Copyright (C) 2023 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.permission.access.immutable
18 
19 import android.util.SparseBooleanArray
20 
21 /** Immutable set with index-based access and [Int] elements. */
22 sealed class IntSet(internal val array: SparseBooleanArray) : Immutable<MutableIntSet> {
23     val size: Int
24         get() = array.size()
25 
isEmptynull26     fun isEmpty(): Boolean = array.size() == 0
27 
28     operator fun contains(element: Int): Boolean = array.contains(element)
29 
30     fun indexOf(element: Int): Int = array.indexOfKey(element)
31 
32     fun elementAt(index: Int): Int = array.keyAt(index)
33 
34     override fun toMutable(): MutableIntSet = MutableIntSet(this)
35 
36     override fun toString(): String = array.toString()
37 }
38 
39 /** Mutable set with index-based access and [Int] elements. */
40 class MutableIntSet(array: SparseBooleanArray = SparseBooleanArray()) : IntSet(array) {
41     constructor(intSet: IntSet) : this(intSet.array.clone())
42 
43     fun add(element: Int): Boolean =
44         if (array.contains(element)) {
45             false
46         } else {
47             array.put(element, true)
48             true
49         }
50 
51     fun remove(element: Int): Boolean {
52         val index = array.indexOfKey(element)
53         return if (index >= 0) {
54             array.removeAt(index)
55             true
56         } else {
57             false
58         }
59     }
60 
61     fun clear() {
62         array.clear()
63     }
64 
65     fun removeAt(index: Int) {
66         array.removeAt(index)
67     }
68 }
69 
70 // Unlike SparseArray, SparseBooleanArray is missing this method.
containsnull71 private fun SparseBooleanArray.contains(key: Int): Boolean = indexOfKey(key) >= 0
72