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    1   /*
    2    * Copyright (c) 2001, 2010, 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 java.io;
   27   
   28   /**
   29    * Utility methods for packing/unpacking primitive values in/out of byte arrays
   30    * using big-endian byte ordering.
   31    */
   32   class Bits {
   33   
   34       /*
   35        * Methods for unpacking primitive values from byte arrays starting at
   36        * given offsets.
   37        */
   38   
   39       static boolean getBoolean(byte[] b, int off) {
   40           return b[off] != 0;
   41       }
   42   
   43       static char getChar(byte[] b, int off) {
   44           return (char) ((b[off + 1] & 0xFF) +
   45                          (b[off] << 8));
   46       }
   47   
   48       static short getShort(byte[] b, int off) {
   49           return (short) ((b[off + 1] & 0xFF) +
   50                           (b[off] << 8));
   51       }
   52   
   53       static int getInt(byte[] b, int off) {
   54           return ((b[off + 3] & 0xFF)      ) +
   55                  ((b[off + 2] & 0xFF) <<  8) +
   56                  ((b[off + 1] & 0xFF) << 16) +
   57                  ((b[off    ]       ) << 24);
   58       }
   59   
   60       static float getFloat(byte[] b, int off) {
   61           return Float.intBitsToFloat(getInt(b, off));
   62       }
   63   
   64       static long getLong(byte[] b, int off) {
   65           return ((b[off + 7] & 0xFFL)      ) +
   66                  ((b[off + 6] & 0xFFL) <<  8) +
   67                  ((b[off + 5] & 0xFFL) << 16) +
   68                  ((b[off + 4] & 0xFFL) << 24) +
   69                  ((b[off + 3] & 0xFFL) << 32) +
   70                  ((b[off + 2] & 0xFFL) << 40) +
   71                  ((b[off + 1] & 0xFFL) << 48) +
   72                  (((long) b[off])      << 56);
   73       }
   74   
   75       static double getDouble(byte[] b, int off) {
   76           return Double.longBitsToDouble(getLong(b, off));
   77       }
   78   
   79       /*
   80        * Methods for packing primitive values into byte arrays starting at given
   81        * offsets.
   82        */
   83   
   84       static void putBoolean(byte[] b, int off, boolean val) {
   85           b[off] = (byte) (val ? 1 : 0);
   86       }
   87   
   88       static void putChar(byte[] b, int off, char val) {
   89           b[off + 1] = (byte) (val      );
   90           b[off    ] = (byte) (val >>> 8);
   91       }
   92   
   93       static void putShort(byte[] b, int off, short val) {
   94           b[off + 1] = (byte) (val      );
   95           b[off    ] = (byte) (val >>> 8);
   96       }
   97   
   98       static void putInt(byte[] b, int off, int val) {
   99           b[off + 3] = (byte) (val       );
  100           b[off + 2] = (byte) (val >>>  8);
  101           b[off + 1] = (byte) (val >>> 16);
  102           b[off    ] = (byte) (val >>> 24);
  103       }
  104   
  105       static void putFloat(byte[] b, int off, float val) {
  106           putInt(b, off,  Float.floatToIntBits(val));
  107       }
  108   
  109       static void putLong(byte[] b, int off, long val) {
  110           b[off + 7] = (byte) (val       );
  111           b[off + 6] = (byte) (val >>>  8);
  112           b[off + 5] = (byte) (val >>> 16);
  113           b[off + 4] = (byte) (val >>> 24);
  114           b[off + 3] = (byte) (val >>> 32);
  115           b[off + 2] = (byte) (val >>> 40);
  116           b[off + 1] = (byte) (val >>> 48);
  117           b[off    ] = (byte) (val >>> 56);
  118       }
  119   
  120       static void putDouble(byte[] b, int off, double val) {
  121           putLong(b, off, Double.doubleToLongBits(val));
  122       }
  123   }

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