Java tutorial
/* * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.io; /** * Utility methods for packing/unpacking primitive values in/out of byte arrays * using big-endian byte ordering. */ class Bits { /* * Methods for unpacking primitive values from byte arrays starting at * given offsets. */ static boolean getBoolean(byte[] b, int off) { return b[off] != 0; } static char getChar(byte[] b, int off) { return (char) ((b[off + 1] & 0xFF) + (b[off] << 8)); } static short getShort(byte[] b, int off) { return (short) ((b[off + 1] & 0xFF) + (b[off] << 8)); } static int getInt(byte[] b, int off) { return ((b[off + 3] & 0xFF)) + ((b[off + 2] & 0xFF) << 8) + ((b[off + 1] & 0xFF) << 16) + ((b[off]) << 24); } static float getFloat(byte[] b, int off) { return Float.intBitsToFloat(getInt(b, off)); } static long getLong(byte[] b, int off) { return ((b[off + 7] & 0xFFL)) + ((b[off + 6] & 0xFFL) << 8) + ((b[off + 5] & 0xFFL) << 16) + ((b[off + 4] & 0xFFL) << 24) + ((b[off + 3] & 0xFFL) << 32) + ((b[off + 2] & 0xFFL) << 40) + ((b[off + 1] & 0xFFL) << 48) + (((long) b[off]) << 56); } static double getDouble(byte[] b, int off) { return Double.longBitsToDouble(getLong(b, off)); } /* * Methods for packing primitive values into byte arrays starting at given * offsets. */ static void putBoolean(byte[] b, int off, boolean val) { b[off] = (byte) (val ? 1 : 0); } static void putChar(byte[] b, int off, char val) { b[off + 1] = (byte) (val); b[off] = (byte) (val >>> 8); } static void putShort(byte[] b, int off, short val) { b[off + 1] = (byte) (val); b[off] = (byte) (val >>> 8); } static void putInt(byte[] b, int off, int val) { b[off + 3] = (byte) (val); b[off + 2] = (byte) (val >>> 8); b[off + 1] = (byte) (val >>> 16); b[off] = (byte) (val >>> 24); } static void putFloat(byte[] b, int off, float val) { putInt(b, off, Float.floatToIntBits(val)); } static void putLong(byte[] b, int off, long val) { b[off + 7] = (byte) (val); b[off + 6] = (byte) (val >>> 8); b[off + 5] = (byte) (val >>> 16); b[off + 4] = (byte) (val >>> 24); b[off + 3] = (byte) (val >>> 32); b[off + 2] = (byte) (val >>> 40); b[off + 1] = (byte) (val >>> 48); b[off] = (byte) (val >>> 56); } static void putDouble(byte[] b, int off, double val) { putLong(b, off, Double.doubleToLongBits(val)); } }