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mchange-commons-java
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/*
 * Distributed as part of mchange-commons-java v.0.2.3
 *
 * Copyright (C) 2012 Machinery For Change, Inc.
 *
 * Author: Steve Waldman 
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1, as 
 * published by the Free Software Foundation.
 *
 * This software 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this software; see the file LICENSE.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */


package com.mchange.lang;

public class LongUtils
{
  private LongUtils()
    {}

  public static long longFromByteArray(byte[] bytes, int offset)
    {
      long out = 0;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 0])) << 56;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 1])) << 48;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 2])) << 40;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 3])) << 32;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 4])) << 24;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 5])) << 16;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 6])) <<  8;
      out |= ((long) ByteUtils.toUnsigned(bytes[offset + 7])) <<  0;
      return out;
    }

  public static byte[] byteArrayFromLong(long l)
    {
      byte[] out = new byte[8];
      longIntoByteArray(l, 0, out);
      return out;
    }

  public static void longIntoByteArray(long l, int offset, byte[] bytes)
    {
      bytes[offset + 0] = (byte) ((l >>> 56) & 0xFF);
      bytes[offset + 1] = (byte) ((l >>> 48) & 0xFF);
      bytes[offset + 2] = (byte) ((l >>> 40) & 0xFF);
      bytes[offset + 3] = (byte) ((l >>> 32) & 0xFF);
      bytes[offset + 4] = (byte) ((l >>> 24) & 0xFF);
      bytes[offset + 5] = (byte) ((l >>> 16) & 0xFF);
      bytes[offset + 6] = (byte) ((l >>>  8) & 0xFF);
      bytes[offset + 7] = (byte) ((l >>>  0) & 0xFF);
    }

    public static int fullHashLong( long l )
    { return hashLong( l ); }

    public static int hashLong( long l )
    { return (int) l ^ (int) ( l >>> 32 ); }
}