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comparison graal/com.oracle.max.base/src/com/sun/max/lang/Ints.java @ 3733:e233f5660da4

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Added Java files from Maxine project.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Sat, 17 Dec 2011 19:59:18 +0100
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3732:3e2e8b8abdaf 3733:e233f5660da4
1 /*
2 * Copyright (c) 2007, 2011, 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 package com.sun.max.lang;
24
25 import com.sun.max.util.*;
26
27 /**
28 * Additional methods that one might want in java.lang.Integer
29 * and int array stuff.
30 */
31 public final class Ints {
32
33 // Utility classes should not be instantiated.
34 private Ints() {
35 }
36
37 public static final int SIZE = 4;
38 public static final int WIDTH = 32;
39
40 public static final Range VALUE_RANGE = new Range(Integer.MIN_VALUE, Integer.MAX_VALUE);
41
42 public static final int K = 1024;
43 public static final int M = K * K;
44
45 public static int compare(int greater, int lesser) {
46 if (greater > lesser) {
47 return 1;
48 }
49 if (greater == lesser) {
50 return 0;
51 }
52 return -1;
53 }
54
55 public static int numberOfEffectiveSignedBits(int signed) {
56 if (signed >= 0) {
57 return 33 - Integer.numberOfLeadingZeros(signed);
58 }
59 return 33 - Integer.numberOfLeadingZeros(~signed);
60 }
61
62 public static int numberOfEffectiveUnsignedBits(int unsigned) {
63 return 32 - Integer.numberOfLeadingZeros(unsigned);
64 }
65
66 /**
67 * Returns an integer with all the bits in its two's complement binary representation that are at index {@code
68 * highestBitIndex} or lower set to 1.
69 *
70 * @param highestBitIndex the index of the highest bit to be set in the returned value. Only the low 5 bits of {@code
71 * highestBitIndex} are used. That is, if {@code highestBitIndex > 31} or {@code highestBitIndex < 0} then
72 * the highest bit to be set is given by {@code highestBitSet & 0x1F}.
73 */
74 public static int lowBitsSet(int highestBitIndex) {
75 final int n = highestBitIndex & 0x1f;
76 return (1 << n) | ((1 << n) - 1);
77 }
78
79 /**
80 * Returns an integer with all the bits in its two's complement binary representation that are at index {@code
81 * lowestBitIndex} or higher set to 1.
82 *
83 * @param lowestBitIndex the index of the lowest bit to be set in the returned value. Only the low 5 bits of {@code
84 * lowestBitIndex} are used. That is, if {@code lowestBitIndex > 31} or {@code lowestBitIndex < 0} then
85 * the lowest bit to be set is given by {@code lowestBitSet & 0x1F}.
86 */
87 public static int highBitsSet(int lowestBitIndex) {
88 return ~((1 << lowestBitIndex) - 1);
89 }
90
91 /**
92 * Determines if a given number is zero or a power of two.
93 */
94 public static boolean isPowerOfTwoOrZero(int n) {
95 return Integer.lowestOneBit(n) == n;
96 }
97
98 public static int log2(int n) {
99 if (n <= 0) {
100 throw new ArithmeticException();
101 }
102 return 31 - Integer.numberOfLeadingZeros(n);
103 }
104
105 public static int roundUp(int value, int by) {
106 final int rest = value % by;
107 if (rest == 0) {
108 return value;
109 }
110 if (value < 0) {
111 return value - rest;
112 }
113 return value + (by - rest);
114 }
115
116 /**
117 * Calculates an unsigned integer which is greater than or equal to {@code value} and
118 * is a multiple of {@code by}. Results are undefined if {@code by} is not
119 * a power of two.
120 * @param value the unsigned integer which is to be rounded upwards.
121 * @param by a positive power of two.
122 * @return the unsigned integer calculated by rounding upwards to a multiple of {@code by}.
123 */
124 public static int roundUnsignedUpByPowerOfTwo(int value, int by) {
125 assert isPowerOfTwoOrZero(by);
126 final int mask = by - 1;
127 return (value + mask) & ~mask;
128 }
129
130 /**
131 * Returns the hexadecimal string representation of the given value with at least 8 digits, e.g. 0x0000CAFE.
132 */
133 public static String toHexLiteral(int value) {
134 return "0x" + toPaddedHexString(value, '0');
135 }
136
137 /**
138 * Returns the given value as a hexadecimal number with at least 8 digits, e.g. 0000CAFE.
139 */
140 public static String toPaddedHexString(int n, char pad) {
141 final String s = Integer.toHexString(n).toUpperCase();
142 return Strings.times(pad, 8 - s.length()) + s;
143 }
144
145 public static boolean contains(int[] array, int value) {
146 for (int element : array) {
147 if (element == value) {
148 return true;
149 }
150 }
151 return false;
152 }
153
154 public static int[] append(int[] array, int element) {
155 final int resultLength = array.length + 1;
156 final int[] result = new int[resultLength];
157 System.arraycopy(array, 0, result, 0, array.length);
158 result[array.length] = element;
159 return result;
160 }
161
162 public static int[] append(int[] head, int[] tail) {
163 final int[] result = new int[head.length + tail.length];
164 System.arraycopy(head, 0, result, 0, head.length);
165 System.arraycopy(tail, 0, result, head.length, tail.length);
166 return result;
167 }
168
169 public static int[] createRange(int first, int last) {
170 if (first > last) {
171 throw new IllegalArgumentException();
172 }
173 final int n = last + 1 - first;
174 final int[] result = new int[n];
175 for (int i = 0; i < n; i++) {
176 result[i] = first + i;
177 }
178 return result;
179 }
180
181 public static void copyAll(int[] fromArray, int[] toArray) {
182 for (int i = 0; i < fromArray.length; i++) {
183 toArray[i] = fromArray[i];
184 }
185 }
186
187 /**
188 * Returns a string representation of the contents of the specified array.
189 * Adjacent elements are separated by the specified separator. Elements are
190 * converted to strings as by <tt>String.valueOf(int)</tt>.
191 *
192 * @param array the array whose string representation to return
193 * @param separator the separator to use
194 * @return a string representation of <tt>array</tt>
195 * @throws NullPointerException if {@code array} or {@code separator} is null
196 */
197 public static String toString(int[] array, String separator) {
198 if (array == null || separator == null) {
199 throw new NullPointerException();
200 }
201 if (array.length == 0) {
202 return "";
203 }
204
205 final StringBuilder buf = new StringBuilder();
206 buf.append(array[0]);
207
208 for (int i = 1; i < array.length; i++) {
209 buf.append(separator);
210 buf.append(array[i]);
211 }
212
213 return buf.toString();
214 }
215
216 private static final int [] sizeBase10Table = {
217 9,
218 99,
219 999,
220 9999,
221 99999,
222 999999,
223 9999999,
224 99999999,
225 999999999, Integer.MAX_VALUE
226 };
227
228 /**
229 * Computes the numbers of characters in the base-10 string representation of a given integer, including the '-'
230 * prefix for a negative integer. That is, this method computes the length of the String returned by
231 * {@link Integer#toString(int)} without requiring a String object to be created.
232 *
233 * @param i an integer
234 * @return the length of the string that would be returned by calling {@link Integer#toString(int)} with {@code i}
235 * as the argument
236 */
237 public static int sizeOfBase10String(int x) {
238 if (x == Integer.MIN_VALUE) {
239 return "-2147483648".length();
240 }
241 final int posX = x < 0 ? -x : x;
242 for (int i = 0;; i++) {
243 if (posX <= sizeBase10Table[i]) {
244 if (x < 0) {
245 return i + 2;
246 }
247 return i + 1;
248 }
249 }
250 }
251
252 /**
253 * @see Longs#toUnitsString(long, boolean)
254 */
255 public static String toUnitsString(long number, boolean onlyPowerOfTwo) {
256 return Longs.toUnitsString(number, onlyPowerOfTwo);
257 }
258
259 /**
260 * Computes the minimum value in an array of integers.
261 *
262 * @param ints the array of integers from which the minimum is computed. This array must have at least one element.
263 * @return the minimum value in {@code ints}
264 * @throws ArrayIndexOutOfBoundsException if {@code ints.length == 0}
265 */
266 public static int min(int[] ints) {
267 int min = ints[0];
268 for (int n : ints) {
269 if (n < min) {
270 min = n;
271 }
272 }
273 return min;
274 }
275
276 /**
277 * Computes the maximum value in an array of integers.
278 *
279 * @param ints the array of integers from which the maximum is computed. This array must have at least one element.
280 * @return the maximum value in {@code ints}
281 * @throws ArrayIndexOutOfBoundsException if {@code ints.length == 0}
282 */
283 public static int max(int[] ints) {
284 int max = ints[0];
285 for (int n : ints) {
286 if (n > max) {
287 max = n;
288 }
289 }
290 return max;
291 }
292
293 }