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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 | } | ||