1 /*
2 * Copyright (c) 2010, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24
25 package org.graalvm.compiler.core.common.util;
26
27 import java.util.Arrays;
28
29 /**
30 * An expandable and indexable list of {@code int}s.
31 *
32 * This class avoids the boxing/unboxing incurred by {@code ArrayList<Integer>}.
33 */
34 public final class IntList {
35
36 private static final int[] EMPTY_INT_ARRAY = new int[0];
37
38 private int[] array;
39 private int size;
40
41 /**
42 * Creates an int list with a specified initial capacity.
43 *
44 * @param initialCapacity
45 */
46 public IntList(int initialCapacity) {
47 array = new int[initialCapacity];
48 }
49
50 /**
51 * Creates an int list with a specified initial array.
52 *
53 * @param array the initial array used for the list (no copy is made)
54 * @param initialSize the initial {@linkplain #size() size} of the list (must be less than or
55 * equal to {@code array.length}
56 */
57 public IntList(int[] array, int initialSize) {
58 assert initialSize <= array.length;
59 this.array = array;
60 this.size = initialSize;
61 }
62
63 /**
64 * Makes a new int list by copying a range from a given int list.
65 *
66 * @param other the list from which a range of values is to be copied into the new list
67 * @param startIndex the index in {@code other} at which to start copying
68 * @param length the number of values to copy from {@code other}
69 * @return a new int list whose {@linkplain #size() size} and capacity is {@code length}
70 */
71 public static IntList copy(IntList other, int startIndex, int length) {
72 return copy(other, startIndex, length, length);
73 }
74
75 /**
76 * Makes a new int list by copying a range from a given int list.
77 *
78 * @param other the list from which a range of values is to be copied into the new list
79 * @param startIndex the index in {@code other} at which to start copying
80 * @param length the number of values to copy from {@code other}
81 * @param initialCapacity the initial capacity of the new int list (must be greater or equal to
82 * {@code length})
83 * @return a new int list whose {@linkplain #size() size} is {@code length}
84 */
85 public static IntList copy(IntList other, int startIndex, int length, int initialCapacity) {
86 assert initialCapacity >= length : "initialCapacity < length";
87 if (initialCapacity == 0) {
88 return new IntList(EMPTY_INT_ARRAY, 0);
89 } else {
90 int[] array = new int[initialCapacity];
91 System.arraycopy(other.array, startIndex, array, 0, length);
92 return new IntList(array, length);
93 }
94 }
95
96 public int size() {
97 return size;
98 }
99
100 /**
101 * Appends a value to the end of this list, increasing its {@linkplain #size() size} by 1.
102 *
103 * @param value the value to append
104 */
105 public void add(int value) {
106 if (size == array.length) {
107 int newSize = (size * 3) / 2 + 1;
108 array = Arrays.copyOf(array, newSize);
109 }
110 array[size++] = value;
111 }
112
113 /**
114 * Gets the value in this list at a given index.
115 *
116 * @param index the index of the element to return
117 * @throws IndexOutOfBoundsException if {@code index < 0 || index >= size()}
118 */
119 public int get(int index) {
120 if (index >= size) {
121 throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
122 }
123 return array[index];
124 }
125
126 /**
127 * Sets the size of this list to 0.
128 */
129 public void clear() {
130 size = 0;
131 }
132
133 /**
134 * Sets a value at a given index in this list.
135 *
136 * @param index the index of the element to update
137 * @param value the new value of the element
138 * @throws IndexOutOfBoundsException if {@code index < 0 || index >= size()}
139 */
140 public void set(int index, int value) {
141 if (index >= size) {
142 throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
143 }
144 array[index] = value;
145 }
146
147 /**
148 * Adjusts the {@linkplain #size() size} of this int list.
149 *
150 * If {@code newSize > size()}, sufficient 0 elements are {@linkplain #add(int) added} until
151 * {@code size() == newSize}. If {@code newSize < size()}, the size is changed to
152 * {@code newSize}.
153 *
154 * @param newSize the new size of this int list
155 */
156 public void setSize(int newSize) {
157 if (newSize < size) {
158 size = newSize;
159 } else if (newSize > size) {
160 array = Arrays.copyOf(array, newSize);
161 }
162 }
163
164 @Override
165 public String toString() {
166 if (array.length == size) {
167 return Arrays.toString(array);
168 }
169 return Arrays.toString(Arrays.copyOf(array, size));
170 }
171 }