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| 1 | +/* | |
| 2 | + * Copyright (c) 1996, 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.math.BigInteger; | |
| 29 | + | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * A low-overhead arbitrary-precision <em>unsigned</em> integer. | |
| 33 | + * This is intended for use with ASN.1 parsing, and printing of | |
| 34 | + * such parsed values. Convert to "BigInteger" if you need to do | |
| 35 | + * arbitrary precision arithmetic, rather than just represent | |
| 36 | + * the number as a wrapped array of bytes. | |
| 37 | + * | |
| 38 | + * <P><em><b>NOTE:</b> This class may eventually disappear, to | |
| 39 | + * be supplanted by big-endian byte arrays which hold both signed | |
| 40 | + * and unsigned arbitrary-precision integers.</em> | |
| 41 | + * | |
| 42 | + * @author David Brownell | |
| 43 | + */ | |
| 44 | +public final class BigInt { | |
| 45 | + | |
| 46 | + // Big endian -- MSB first. | |
| 47 | + private byte[] places; | |
| 48 | + | |
| 49 | + /** | |
| 50 | + * Constructs a "Big" integer from a set of (big-endian) bytes. | |
| 51 | + * Leading zeroes should be stripped off. | |
| 52 | + * | |
| 53 | + * @param data a sequence of bytes, most significant bytes/digits | |
| 54 | + * first. CONSUMED. | |
| 55 | + */ | |
| 56 | + public BigInt(byte[] data) { places = data.clone(); } | |
| 57 | + | |
| 58 | + /** | |
| 59 | + * Constructs a "Big" integer from a "BigInteger", which must be | |
| 60 | + * positive (or zero) in value. | |
| 61 | + */ | |
| 62 | + public BigInt(BigInteger i) { | |
| 63 | + byte[] temp = i.toByteArray(); | |
| 64 | + | |
| 65 | + if ((temp[0] & 0x80) != 0) | |
| 66 | + throw new IllegalArgumentException("negative BigInteger"); | |
| 67 | + | |
| 68 | + // XXX we assume exactly _one_ sign byte is used... | |
| 69 | + | |
| 70 | + if (temp[0] != 0) | |
| 71 | + places = temp; | |
| 72 | + else { | |
| 73 | + places = new byte[temp.length - 1]; | |
| 74 | + for (int j = 1; j < temp.length; j++) | |
| 75 | + places[j - 1] = temp[j]; | |
| 76 | + } | |
| 77 | + } | |
| 78 | + | |
| 79 | + /** | |
| 80 | + * Constructs a "Big" integer from a normal Java integer. | |
| 81 | + * | |
| 82 | + * @param i the java primitive integer | |
| 83 | + */ | |
| 84 | + public BigInt(int i) { | |
| 85 | + if (i < (1 << 8)) { | |
| 86 | + places = new byte[1]; | |
| 87 | + places[0] = (byte) i; | |
| 88 | + } else if (i < (1 << 16)) { | |
| 89 | + places = new byte[2]; | |
| 90 | + places[0] = (byte) (i >> 8); | |
| 91 | + places[1] = (byte) i; | |
| 92 | + } else if (i < (1 << 24)) { | |
| 93 | + places = new byte[3]; | |
| 94 | + places[0] = (byte) (i >> 16); | |
| 95 | + places[1] = (byte) (i >> 8); | |
| 96 | + places[2] = (byte) i; | |
| 97 | + } else { | |
| 98 | + places = new byte[4]; | |
| 99 | + places[0] = (byte) (i >> 24); | |
| 100 | + places[1] = (byte) (i >> 16); | |
| 101 | + places[2] = (byte) (i >> 8); | |
| 102 | + places[3] = (byte) i; | |
| 103 | + } | |
| 104 | + } | |
| 105 | + | |
| 106 | + /** | |
| 107 | + * Converts the "big" integer to a java primitive integer. | |
| 108 | + * | |
| 109 | + * @excpet NumberFormatException if 32 bits is insufficient. | |
| 110 | + */ | |
| 111 | + public int toInt() { | |
| 112 | + if (places.length > 4) | |
| 113 | + throw new NumberFormatException("BigInt.toLong, too big"); | |
| 114 | + int retval = 0, i = 0; | |
| 115 | + for (; i < places.length; i++) | |
| 116 | + retval = (retval << 8) + ((int)places[i] & 0xff); | |
| 117 | + return retval; | |
| 118 | + } | |
| 119 | + | |
| 120 | + /** | |
| 121 | + * Returns a hexadecimal printed representation. The value is | |
| 122 | + * formatted to fit on lines of at least 75 characters, with | |
| 123 | + * embedded newlines. Words are separated for readability, | |
| 124 | + * with eight words (32 bytes) per line. | |
| 125 | + */ | |
| 126 | + public String toString() { return hexify(); } | |
| 127 | + | |
| 128 | + /** | |
| 129 | + * Returns a BigInteger value which supports many arithmetic | |
| 130 | + * operations. Assumes negative values will never occur. | |
| 131 | + */ | |
| 132 | + public BigInteger toBigInteger() | |
| 133 | + { return new BigInteger(1, places); } | |
| 134 | + | |
| 135 | + /** | |
| 136 | + * Returns the data as a byte array. The most significant bit | |
| 137 | + * of the array is bit zero (as in <code>java.math.BigInteger</code>). | |
| 138 | + */ | |
| 139 | + public byte[] toByteArray() { return places.clone(); } | |
| 140 | + | |
| 141 | + private static final String digits = "0123456789abcdef"; | |
| 142 | + private String hexify() { | |
| 143 | + if (places.length == 0) | |
| 144 | + return " 0 "; | |
| 145 | + | |
| 146 | + StringBuffer buf = new StringBuffer(places.length * 2); | |
| 147 | + buf.append(" "); // four spaces | |
| 148 | + for (int i = 0; i < places.length; i++) { | |
| 149 | + buf.append(digits.charAt((places[i] >> 4) & 0x0f)); | |
| 150 | + buf.append(digits.charAt(places[i] & 0x0f)); | |
| 151 | + if (((i + 1) % 32) == 0) { | |
| 152 | + if ((i + 1) != places.length) | |
| 153 | + buf.append("\n "); // line after four words | |
| 154 | + } else if (((i + 1) % 4) == 0) | |
| 155 | + buf.append(' '); // space between words | |
| 156 | + } | |
| 157 | + return buf.toString(); | |
| 158 | + } | |
| 159 | + | |
| 160 | + /** | |
| 161 | + * Returns true iff the parameter is a numerically equivalent | |
| 162 | + * BigInt. | |
| 163 | + * | |
| 164 | + * @param other the object being compared with this one. | |
| 165 | + */ | |
| 166 | + public boolean equals(Object other) { | |
| 167 | + if (other instanceof BigInt) | |
| 168 | + return equals((BigInt) other); | |
| 169 | + return false; | |
| 170 | + } | |
| 171 | + | |
| 172 | + /** | |
| 173 | + * Returns true iff the parameter is numerically equivalent. | |
| 174 | + * | |
| 175 | + * @param other the BigInt being compared with this one. | |
| 176 | + */ | |
| 177 | + public boolean equals(BigInt other) { | |
| 178 | + if (this == other) | |
| 179 | + return true; | |
| 180 | + | |
| 181 | + byte[] otherPlaces = other.toByteArray(); | |
| 182 | + if (places.length != otherPlaces.length) | |
| 183 | + return false; | |
| 184 | + for (int i = 0; i < places.length; i++) | |
| 185 | + if (places[i] != otherPlaces[i]) | |
| 186 | + return false; | |
| 187 | + return true; | |
| 188 | + } | |
| 189 | + | |
| 190 | + /** | |
| 191 | + * Returns a hashcode for this BigInt. | |
| 192 | + * | |
| 193 | + * @return a hashcode for this BigInt. | |
| 194 | + */ | |
| 195 | + public int hashCode() { | |
| 196 | + return hexify().hashCode(); | |
| 197 | + } | |
| 198 | +} | |