Showing the changes to java/pkg/sun/security/util/BitArray.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,275 @@ | ||
| 1 | +/* | |
| 2 | + * Copyright (c) 1997, 2006, 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package sun.security.util; | |
| 27 | + | |
| 28 | +import java.io.ByteArrayOutputStream; | |
| 29 | +import java.util.Arrays; | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * A packed array of booleans. | |
| 33 | + * | |
| 34 | + * @author Joshua Bloch | |
| 35 | + * @author Douglas Hoover | |
| 36 | + */ | |
| 37 | + | |
| 38 | +public class BitArray { | |
| 39 | + | |
| 40 | + private byte[] repn; | |
| 41 | + private int length; | |
| 42 | + | |
| 43 | + private static final int BITS_PER_UNIT = 8; | |
| 44 | + | |
| 45 | + private static int subscript(int idx) { | |
| 46 | + return idx / BITS_PER_UNIT; | |
| 47 | + } | |
| 48 | + | |
| 49 | + private static int position(int idx) { // bits big-endian in each unit | |
| 50 | + return 1 << (BITS_PER_UNIT - 1 - (idx % BITS_PER_UNIT)); | |
| 51 | + } | |
| 52 | + | |
| 53 | + /** | |
| 54 | + * Creates a BitArray of the specified size, initialized to zeros. | |
| 55 | + */ | |
| 56 | + public BitArray(int length) throws IllegalArgumentException { | |
| 57 | + if (length < 0) { | |
| 58 | + throw new IllegalArgumentException("Negative length for BitArray"); | |
| 59 | + } | |
| 60 | + | |
| 61 | + this.length = length; | |
| 62 | + | |
| 63 | + repn = new byte[(length + BITS_PER_UNIT - 1)/BITS_PER_UNIT]; | |
| 64 | + } | |
| 65 | + | |
| 66 | + | |
| 67 | + /** | |
| 68 | + * Creates a BitArray of the specified size, initialized from the | |
| 69 | + * specified byte array. The most significant bit of a[0] gets | |
| 70 | + * index zero in the BitArray. The array a must be large enough | |
| 71 | + * to specify a value for every bit in the BitArray. In other words, | |
| 72 | + * 8*a.length <= length. | |
| 73 | + */ | |
| 74 | + public BitArray(int length, byte[] a) throws IllegalArgumentException { | |
| 75 | + | |
| 76 | + if (length < 0) { | |
| 77 | + throw new IllegalArgumentException("Negative length for BitArray"); | |
| 78 | + } | |
| 79 | + if (a.length * BITS_PER_UNIT < length) { | |
| 80 | + throw new IllegalArgumentException("Byte array too short to represent " + | |
| 81 | + "bit array of given length"); | |
| 82 | + } | |
| 83 | + | |
| 84 | + this.length = length; | |
| 85 | + | |
| 86 | + int repLength = ((length + BITS_PER_UNIT - 1)/BITS_PER_UNIT); | |
| 87 | + int unusedBits = repLength*BITS_PER_UNIT - length; | |
| 88 | + byte bitMask = (byte) (0xFF << unusedBits); | |
| 89 | + | |
| 90 | + /* | |
| 91 | + normalize the representation: | |
| 92 | + 1. discard extra bytes | |
| 93 | + 2. zero out extra bits in the last byte | |
| 94 | + */ | |
| 95 | + repn = new byte[repLength]; | |
| 96 | + System.arraycopy(a, 0, repn, 0, repLength); | |
| 97 | + if (repLength > 0) { | |
| 98 | + repn[repLength - 1] &= bitMask; | |
| 99 | + } | |
| 100 | + } | |
| 101 | + | |
| 102 | + /** | |
| 103 | + * Create a BitArray whose bits are those of the given array | |
| 104 | + * of Booleans. | |
| 105 | + */ | |
| 106 | + public BitArray(boolean[] bits) { | |
| 107 | + length = bits.length; | |
| 108 | + repn = new byte[(length + 7)/8]; | |
| 109 | + | |
| 110 | + for (int i=0; i < length; i++) { | |
| 111 | + set(i, bits[i]); | |
| 112 | + } | |
| 113 | + } | |
| 114 | + | |
| 115 | + | |
| 116 | + /** | |
| 117 | + * Copy constructor (for cloning). | |
| 118 | + */ | |
| 119 | + private BitArray(BitArray ba) { | |
| 120 | + length = ba.length; | |
| 121 | + repn = ba.repn.clone(); | |
| 122 | + } | |
| 123 | + | |
| 124 | + /** | |
| 125 | + * Returns the indexed bit in this BitArray. | |
| 126 | + */ | |
| 127 | + public boolean get(int index) throws ArrayIndexOutOfBoundsException { | |
| 128 | + if (index < 0 || index >= length) { | |
| 129 | + throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); | |
| 130 | + } | |
| 131 | + | |
| 132 | + return (repn[subscript(index)] & position(index)) != 0; | |
| 133 | + } | |
| 134 | + | |
| 135 | + /** | |
| 136 | + * Sets the indexed bit in this BitArray. | |
| 137 | + */ | |
| 138 | + public void set(int index, boolean value) | |
| 139 | + throws ArrayIndexOutOfBoundsException { | |
| 140 | + if (index < 0 || index >= length) { | |
| 141 | + throw new ArrayIndexOutOfBoundsException(Integer.toString(index)); | |
| 142 | + } | |
| 143 | + int idx = subscript(index); | |
| 144 | + int bit = position(index); | |
| 145 | + | |
| 146 | + if (value) { | |
| 147 | + repn[idx] |= bit; | |
| 148 | + } else { | |
| 149 | + repn[idx] &= ~bit; | |
| 150 | + } | |
| 151 | + } | |
| 152 | + | |
| 153 | + /** | |
| 154 | + * Returns the length of this BitArray. | |
| 155 | + */ | |
| 156 | + public int length() { | |
| 157 | + return length; | |
| 158 | + } | |
| 159 | + | |
| 160 | + /** | |
| 161 | + * Returns a Byte array containing the contents of this BitArray. | |
| 162 | + * The bit stored at index zero in this BitArray will be copied | |
| 163 | + * into the most significant bit of the zeroth element of the | |
| 164 | + * returned byte array. The last byte of the returned byte array | |
| 165 | + * will be contain zeros in any bits that do not have corresponding | |
| 166 | + * bits in the BitArray. (This matters only if the BitArray's size | |
| 167 | + * is not a multiple of 8.) | |
| 168 | + */ | |
| 169 | + public byte[] toByteArray() { | |
| 170 | + return repn.clone(); | |
| 171 | + } | |
| 172 | + | |
| 173 | + public boolean equals(Object obj) { | |
| 174 | + if (obj == this) return true; | |
| 175 | + if (obj == null || !(obj instanceof BitArray)) return false; | |
| 176 | + | |
| 177 | + BitArray ba = (BitArray) obj; | |
| 178 | + | |
| 179 | + if (ba.length != length) return false; | |
| 180 | + | |
| 181 | + for (int i = 0; i < repn.length; i += 1) { | |
| 182 | + if (repn[i] != ba.repn[i]) return false; | |
| 183 | + } | |
| 184 | + return true; | |
| 185 | + } | |
| 186 | + | |
| 187 | + /** | |
| 188 | + * Return a boolean array with the same bit values a this BitArray. | |
| 189 | + */ | |
| 190 | + public boolean[] toBooleanArray() { | |
| 191 | + boolean[] bits = new boolean[length]; | |
| 192 | + | |
| 193 | + for (int i=0; i < length; i++) { | |
| 194 | + bits[i] = get(i); | |
| 195 | + } | |
| 196 | + return bits; | |
| 197 | + } | |
| 198 | + | |
| 199 | + /** | |
| 200 | + * Returns a hash code value for this bit array. | |
| 201 | + * | |
| 202 | + * @return a hash code value for this bit array. | |
| 203 | + */ | |
| 204 | + public int hashCode() { | |
| 205 | + int hashCode = 0; | |
| 206 | + | |
| 207 | + for (int i = 0; i < repn.length; i++) | |
| 208 | + hashCode = 31*hashCode + repn[i]; | |
| 209 | + | |
| 210 | + return hashCode ^ length; | |
| 211 | + } | |
| 212 | + | |
| 213 | + | |
| 214 | + public Object clone() { | |
| 215 | + return new BitArray(this); | |
| 216 | + } | |
| 217 | + | |
| 218 | + | |
| 219 | + private static final byte[][] NYBBLE = { | |
| 220 | + { (byte)'0',(byte)'0',(byte)'0',(byte)'0'}, | |
| 221 | + { (byte)'0',(byte)'0',(byte)'0',(byte)'1'}, | |
| 222 | + { (byte)'0',(byte)'0',(byte)'1',(byte)'0'}, | |
| 223 | + { (byte)'0',(byte)'0',(byte)'1',(byte)'1'}, | |
| 224 | + { (byte)'0',(byte)'1',(byte)'0',(byte)'0'}, | |
| 225 | + { (byte)'0',(byte)'1',(byte)'0',(byte)'1'}, | |
| 226 | + { (byte)'0',(byte)'1',(byte)'1',(byte)'0'}, | |
| 227 | + { (byte)'0',(byte)'1',(byte)'1',(byte)'1'}, | |
| 228 | + { (byte)'1',(byte)'0',(byte)'0',(byte)'0'}, | |
| 229 | + { (byte)'1',(byte)'0',(byte)'0',(byte)'1'}, | |
| 230 | + { (byte)'1',(byte)'0',(byte)'1',(byte)'0'}, | |
| 231 | + { (byte)'1',(byte)'0',(byte)'1',(byte)'1'}, | |
| 232 | + { (byte)'1',(byte)'1',(byte)'0',(byte)'0'}, | |
| 233 | + { (byte)'1',(byte)'1',(byte)'0',(byte)'1'}, | |
| 234 | + { (byte)'1',(byte)'1',(byte)'1',(byte)'0'}, | |
| 235 | + { (byte)'1',(byte)'1',(byte)'1',(byte)'1'} | |
| 236 | + }; | |
| 237 | + | |
| 238 | + private static final int BYTES_PER_LINE = 8; | |
| 239 | + | |
| 240 | + /** | |
| 241 | + * Returns a string representation of this BitArray. | |
| 242 | + */ | |
| 243 | + public String toString() { | |
| 244 | + ByteArrayOutputStream out = new ByteArrayOutputStream(); | |
| 245 | + | |
| 246 | + for (int i = 0; i < repn.length - 1; i++) { | |
| 247 | + out.write(NYBBLE[(repn[i] >> 4) & 0x0F], 0, 4); | |
| 248 | + out.write(NYBBLE[repn[i] & 0x0F], 0, 4); | |
| 249 | + | |
| 250 | + if (i % BYTES_PER_LINE == BYTES_PER_LINE - 1) { | |
| 251 | + out.write('\n'); | |
| 252 | + } else { | |
| 253 | + out.write(' '); | |
| 254 | + } | |
| 255 | + } | |
| 256 | + | |
| 257 | + // in last byte of repn, use only the valid bits | |
| 258 | + for (int i = BITS_PER_UNIT * (repn.length - 1); i < length; i++) { | |
| 259 | + out.write(get(i) ? '1' : '0'); | |
| 260 | + } | |
| 261 | + | |
| 262 | + return new String(out.toByteArray()); | |
| 263 | + | |
| 264 | + } | |
| 265 | + | |
| 266 | + public BitArray truncate() { | |
| 267 | + for (int i=length-1; i>=0; i--) { | |
| 268 | + if (get(i)) { | |
| 269 | + return new BitArray(i+1, Arrays.copyOf(repn, (i + BITS_PER_UNIT)/BITS_PER_UNIT)); | |
| 270 | + } | |
| 271 | + } | |
| 272 | + return new BitArray(1); | |
| 273 | + } | |
| 274 | + | |
| 275 | +} | |