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| 1 | +/* |
| 2 | + * #%L |
| 3 | + * SciJava Common shared library for SciJava software. |
| 4 | + * %% |
| 5 | + * Copyright (C) 2009 - 2014 Board of Regents of the University of |
| 6 | + * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck |
| 7 | + * Institute of Molecular Cell Biology and Genetics. |
| 8 | + * %% |
| 9 | + * Redistribution and use in source and binary forms, with or without |
| 10 | + * modification, are permitted provided that the following conditions are met: |
| 11 | + * |
| 12 | + * 1. Redistributions of source code must retain the above copyright notice, |
| 13 | + * this list of conditions and the following disclaimer. |
| 14 | + * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 15 | + * this list of conditions and the following disclaimer in the documentation |
| 16 | + * and/or other materials provided with the distribution. |
| 17 | + * |
| 18 | + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| 19 | + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 20 | + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 21 | + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE |
| 22 | + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 23 | + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 24 | + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 25 | + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 26 | + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 27 | + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 28 | + * POSSIBILITY OF SUCH DAMAGE. |
| 29 | + * #L% |
| 30 | + */ |
| 31 | + |
| 32 | +package org.scijava.util; |
| 33 | + |
| 34 | +import java.io.UnsupportedEncodingException; |
| 35 | +import java.security.MessageDigest; |
| 36 | +import java.security.NoSuchAlgorithmException; |
| 37 | + |
| 38 | +import javax.xml.bind.DatatypeConverter; |
| 39 | + |
| 40 | +/** |
| 41 | + * Utility class for computing cryptographic hashes. |
| 42 | + * |
| 43 | + * @author Curtis Rueden |
| 44 | + * @author Johannes Schindelin |
| 45 | + */ |
| 46 | +public final class DigestUtils { |
| 47 | + |
| 48 | + private final static char[] hex = { '0', '1', '2', '3', '4', '5', '6', '7', |
| 49 | + '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; |
| 50 | + |
| 51 | + private DigestUtils() { |
| 52 | + // NB: Prevent instantiation of utility class. |
| 53 | + } |
| 54 | + |
| 55 | + /** |
| 56 | + * Converts the given byte array to a string. UTF-8 encoding is used if |
| 57 | + * available, with the platform's default encoding as a fallback. |
| 58 | + */ |
| 59 | + public static String string(final byte[] bytes) { |
| 60 | + try { |
| 61 | + return new String(bytes, "UTF-8"); |
| 62 | + } |
| 63 | + catch (final UnsupportedEncodingException exc) { |
| 64 | + return new String(bytes); |
| 65 | + } |
| 66 | + } |
| 67 | + |
| 68 | + /** |
| 69 | + * Converts the given string to a byte array. UTF-8 encoding is used if |
| 70 | + * available, with the platform's default encoding as a fallback. |
| 71 | + */ |
| 72 | + public static byte[] bytes(final String s) { |
| 73 | + try { |
| 74 | + return s.getBytes("UTF-8"); |
| 75 | + } |
| 76 | + catch (final UnsupportedEncodingException exc) { |
| 77 | + return s.getBytes(); |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + /** Converts the given integer into a byte array. */ |
| 82 | + public static byte[] bytes(final int i) { |
| 83 | + return new byte[] { |
| 84 | + (byte) (0xff & (i >>> 24)), |
| 85 | + (byte) (0xff & (i >>> 16)), |
| 86 | + (byte) (0xff & (i >>> 8)), |
| 87 | + (byte) (0xff & i), |
| 88 | + }; |
| 89 | + } |
| 90 | + |
| 91 | + /** Converts the given byte array to a hexidecimal string. */ |
| 92 | + public static String hex(final byte[] bytes) { |
| 93 | + final char[] buffer = new char[bytes.length * 2]; |
| 94 | + for (int i = 0; i < bytes.length; i++) { |
| 95 | + buffer[i * 2] = hex[(bytes[i] & 0xf0) >> 4]; |
| 96 | + buffer[i * 2 + 1] = hex[bytes[i] & 0xf]; |
| 97 | + } |
| 98 | + return new String(buffer); |
| 99 | + } |
| 100 | + |
| 101 | + /** Converts the given byte array to a base64 string. */ |
| 102 | + public static String base64(final byte[] bytes) { |
| 103 | + return DatatypeConverter.printBase64Binary(bytes); |
| 104 | + } |
| 105 | + |
| 106 | + /** |
| 107 | + * Gets the Java hash code of the given string, as a byte array. |
| 108 | + * |
| 109 | + * @see String#hashCode() |
| 110 | + */ |
| 111 | + public static byte[] hash(final String s) { |
| 112 | + return bytes(s.hashCode()); |
| 113 | + } |
| 114 | + |
| 115 | + /** |
| 116 | + * Gets the hash code of the given byte array, as a byte array. |
| 117 | + * |
| 118 | + * @see String#hashCode() |
| 119 | + * @see #string(byte[]) |
| 120 | + */ |
| 121 | + public static byte[] hash(final byte[] bytes) { |
| 122 | + // NB: We cannot use the hash code of the byte array directly, |
| 123 | + // because it is not deterministic. Primitive byte arrays use the |
| 124 | + // default Object implementation of hashCode(), which differs for |
| 125 | + // every object instance. We need a consistent hash code, so we |
| 126 | + // convert to String first, which fulfills this requirement. |
| 127 | + return hash(string(bytes)); |
| 128 | + } |
| 129 | + |
| 130 | + /** Gets the given byte array's SHA-1 checksum, or null if unavailable. */ |
| 131 | + public static byte[] sha1(final byte[] bytes) { |
| 132 | + return digest("SHA-1", bytes); |
| 133 | + } |
| 134 | + |
| 135 | + /** Gets the given byte array's MD5 checksum, or null if unavailable. */ |
| 136 | + public static byte[] md5(final byte[] bytes) { |
| 137 | + return digest("MD5", bytes); |
| 138 | + } |
| 139 | + |
| 140 | + /** |
| 141 | + * Gets the given byte array's hash value according to the specified |
| 142 | + * algorithm. |
| 143 | + * |
| 144 | + * @param algorithm The algorithm to use when generating the hash value. |
| 145 | + * @param bytes The byte array for which to compute the hash value. |
| 146 | + * @return The computed hash value, or null if the digest algorithm is not |
| 147 | + * available. |
| 148 | + * @see MessageDigest |
| 149 | + */ |
| 150 | + public static byte[] digest(final String algorithm, final byte[] bytes) { |
| 151 | + try { |
| 152 | + final MessageDigest digest = MessageDigest.getInstance(algorithm); |
| 153 | + digest.update(bytes); |
| 154 | + return digest.digest(); |
| 155 | + } |
| 156 | + catch (final NoSuchAlgorithmException exc) { |
| 157 | + return null; |
| 158 | + } |
| 159 | + } |
| 160 | + |
| 161 | + /** |
| 162 | + * Gets the given string's best available hash. Tries SHA-1 first, then MD5, |
| 163 | + * then Java hash code. |
| 164 | + * |
| 165 | + * @see #bytes(String) |
| 166 | + * @see #sha1(byte[]) |
| 167 | + * @see #md5(byte[]) |
| 168 | + * @see #hash(String) |
| 169 | + */ |
| 170 | + public static byte[] best(final String s) { |
| 171 | + final byte[] bytes = bytes(s); |
| 172 | + byte[] best = sha1(bytes); |
| 173 | + if (best == null) best = md5(bytes); |
| 174 | + if (best == null) best = hash(s); |
| 175 | + return best; |
| 176 | + } |
| 177 | + |
| 178 | + /** |
| 179 | + * Gets the given byte array's best available hash. Tries SHA-1 first, then |
| 180 | + * MD5, then Java hash code. |
| 181 | + * |
| 182 | + * @see #sha1(byte[]) |
| 183 | + * @see #md5(byte[]) |
| 184 | + * @see #hash(byte[]) |
| 185 | + */ |
| 186 | + public static byte[] best(final byte[] bytes) { |
| 187 | + byte[] best = sha1(bytes); |
| 188 | + if (best == null) best = md5(bytes); |
| 189 | + if (best == null) best = hash(bytes); |
| 190 | + return best; |
| 191 | + } |
| 192 | + |
| 193 | + /** |
| 194 | + * Gets the hex string of the given string's best available hash. |
| 195 | + * |
| 196 | + * @see #best(String) |
| 197 | + * @see #hex(byte[]) |
| 198 | + */ |
| 199 | + public static String bestHex(final String text) { |
| 200 | + return hex(best(text)); |
| 201 | + } |
| 202 | + |
| 203 | + /** |
| 204 | + * Gets the hex string of the given byte array's best available hash. |
| 205 | + * |
| 206 | + * @see #best(byte[]) |
| 207 | + * @see #hex(byte[]) |
| 208 | + */ |
| 209 | + public static String bestHex(final byte[] bytes) { |
| 210 | + return hex(best(bytes)); |
| 211 | + } |
| 212 | + |
| 213 | + /** |
| 214 | + * Gets the base64 string of the given string's best available hash. |
| 215 | + * |
| 216 | + * @see #best(String) |
| 217 | + * @see #base64(byte[]) |
| 218 | + */ |
| 219 | + public static String bestBase64(final String text) { |
| 220 | + return base64(best(text)); |
| 221 | + } |
| 222 | + |
| 223 | + /** |
| 224 | + * Gets the base64 string of the given byte array's best available hash. |
| 225 | + * |
| 226 | + * @see #best(byte[]) |
| 227 | + * @see #base64(byte[]) |
| 228 | + */ |
| 229 | + public static String bestBase64(final byte[] bytes) { |
| 230 | + return base64(best(bytes)); |
| 231 | + } |
| 232 | + |
| 233 | +} |
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