| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.openjpa.lib.util; |
| |
| /** |
| * This class came from the Apache Commons Id sandbox project in support |
| * of the UUIDGenerator implementation. |
| * |
| * <p>Static methods for managing byte arrays (all methods follow Big |
| * Endian order where most significant bits are in front).</p> |
| */ |
| public final class Bytes { |
| |
| /** |
| * <p>Hide constructor in utility class.</p> |
| */ |
| private Bytes() { |
| } |
| |
| /** |
| * Appends two bytes array into one. |
| * |
| * @param a A byte[]. |
| * @param b A byte[]. |
| * @return A byte[]. |
| */ |
| public static byte[] append(byte[] a, byte[] b) { |
| byte[] z = new byte[a.length + b.length]; |
| System.arraycopy(a, 0, z, 0, a.length); |
| System.arraycopy(b, 0, z, a.length, b.length); |
| return z; |
| } |
| |
| /** |
| * Returns a 8-byte array built from a long. |
| * |
| * @param n The number to convert. |
| * @return A byte[]. |
| */ |
| public static byte[] toBytes(long n) { |
| return toBytes(n, new byte[8]); |
| } |
| |
| /** |
| * Build a 8-byte array from a long. No check is performed on the |
| * array length. |
| * |
| * @param n The number to convert. |
| * @param b The array to fill. |
| * @return A byte[]. |
| */ |
| public static byte[] toBytes(long n, byte[] b) { |
| b[7] = (byte) (n); |
| n >>>= 8; |
| b[6] = (byte) (n); |
| n >>>= 8; |
| b[5] = (byte) (n); |
| n >>>= 8; |
| b[4] = (byte) (n); |
| n >>>= 8; |
| b[3] = (byte) (n); |
| n >>>= 8; |
| b[2] = (byte) (n); |
| n >>>= 8; |
| b[1] = (byte) (n); |
| n >>>= 8; |
| b[0] = (byte) (n); |
| |
| return b; |
| } |
| |
| /** |
| * Build a long from first 8 bytes of the array. |
| * |
| * @param b The byte[] to convert. |
| * @return A long. |
| */ |
| public static long toLong(byte[] b) { |
| return ((((long) b[7]) & 0xFF) |
| + ((((long) b[6]) & 0xFF) << 8) |
| + ((((long) b[5]) & 0xFF) << 16) |
| + ((((long) b[4]) & 0xFF) << 24) |
| + ((((long) b[3]) & 0xFF) << 32) |
| + ((((long) b[2]) & 0xFF) << 40) |
| + ((((long) b[1]) & 0xFF) << 48) |
| + ((((long) b[0]) & 0xFF) << 56)); |
| } |
| |
| /** |
| * Compares two byte arrays for equality. |
| * |
| * @param a A byte[]. |
| * @param b A byte[]. |
| * @return True if the arrays have identical contents. |
| */ |
| public static boolean areEqual(byte[] a, byte[] b) { |
| int aLength = a.length; |
| if (aLength != b.length) { |
| return false; |
| } |
| |
| for (int i = 0; i < aLength; i++) { |
| if (a[i] != b[i]) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * <p>Compares two byte arrays as specified by <code>Comparable</code>. |
| * |
| * @param lhs - left hand value in the comparison operation. |
| * @param rhs - right hand value in the comparison operation. |
| * @return a negative integer, zero, or a positive integer as |
| * <code>lhs</code> is less than, equal to, or greater than |
| * <code>rhs</code>. |
| */ |
| public static int compareTo(byte[] lhs, byte[] rhs) { |
| if (lhs == rhs) { |
| return 0; |
| } |
| if (lhs == null) { |
| return -1; |
| } |
| if (rhs == null) { |
| return +1; |
| } |
| if (lhs.length != rhs.length) { |
| return ((lhs.length < rhs.length) ? -1 : +1); |
| } |
| for (int i = 0; i < lhs.length; i++) { |
| if (lhs[i] < rhs[i]) { |
| return -1; |
| } else if (lhs[i] > rhs[i]) { |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| /** |
| * Build a short from first 2 bytes of the array. |
| * |
| * @param b The byte[] to convert. |
| * @return A short. |
| */ |
| public static short toShort(byte[] b) { |
| return (short) ((b[1] & 0xFF) + ((b[0] & 0xFF) << 8)); |
| } |
| } |