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// BitSet - A vector of bits.
/* Copyright (C) 1998, 1999 Cygnus Solutions
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
package java.util;
import java.io.Serializable;
/**
* @author Tom Tromey <tromey@cygnus.com>
* @date October 23, 1998.
*/
/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
* hashCode algorithm taken from JDK 1.2 docs.
*/
public final class BitSet implements Cloneable, Serializable
{
public void and (BitSet bs)
{
if (bs == null)
throw new NullPointerException ();
int max = Math.min(bits.length, bs.bits.length);
int i;
for (i = 0; i < max; ++i)
bits[i] &= bs.bits[i];
for ( ; i < bits.length; ++i)
bits[i] = 0;
}
public BitSet ()
{
this (64);
}
public BitSet (int nbits)
{
if (nbits < 0)
throw new NegativeArraySizeException ();
int length = nbits / 64;
if (nbits % 64 != 0)
++length;
bits = new long[length];
}
public void clear (int pos)
{
if (pos < 0)
throw new IndexOutOfBoundsException ();
int bit = pos % 64;
int offset = pos / 64;
ensure (offset);
bits[offset] &= ~ (1L << bit);
}
public Object clone ()
{
BitSet bs = new BitSet (bits.length * 64);
System.arraycopy(bits, 0, bs.bits, 0, bits.length);
return bs;
}
public boolean equals (Object obj)
{
if (! (obj instanceof BitSet))
return false;
BitSet bs = (BitSet) obj;
int max = Math.min(bits.length, bs.bits.length);
int i;
for (i = 0; i < max; ++i)
if (bits[i] != bs.bits[i])
return false;
// If one is larger, check to make sure all extra bits are 0.
for (int j = i; j < bits.length; ++j)
if (bits[j] != 0)
return false;
for (int j = i; j < bs.bits.length; ++j)
if (bs.bits[j] != 0)
return false;
return true;
}
public boolean get (int pos)
{
if (pos < 0)
throw new IndexOutOfBoundsException ();
int bit = pos % 64;
int offset = pos / 64;
if (offset >= bits.length)
return false;
return (bits[offset] & (1L << bit)) == 0 ? false : true;
}
public int hashCode ()
{
long h = 1234;
for (int i = bits.length - 1; i >= 0; --i)
h ^= bits[i] * (i + 1);
return (int) ((h >> 32) ^ h);
}
public void or (BitSet bs)
{
if (bs == null)
throw new NullPointerException ();
ensure (bs.bits.length - 1);
int i;
for (i = 0; i < bs.bits.length; ++i)
bits[i] |= bs.bits[i];
}
public void set (int pos)
{
if (pos < 0)
throw new IndexOutOfBoundsException ();
int bit = pos % 64;
int offset = pos / 64;
ensure (offset);
bits[offset] |= 1L << bit;
}
public int size ()
{
return bits.length * 64;
}
public String toString ()
{
StringBuffer result = new StringBuffer ("{");
boolean first = true;
for (int i = 0; i < bits.length; ++i)
{
int bit = 1;
long word = bits[i];
for (int j = 0; j < 64; ++j)
{
if ((word & bit) != 0)
{
if (! first)
result.append(", ");
result.append(64 * i + j);
first = false;
}
bit <<= 1;
}
}
return result.append("}").toString();
}
public void xor (BitSet bs)
{
if (bs == null)
throw new NullPointerException ();
ensure (bs.bits.length - 1);
int i;
for (i = 0; i < bs.bits.length; ++i)
bits[i] ^= bs.bits[i];
}
// Make sure the vector is big enough.
private final void ensure (int lastElt)
{
if (lastElt + 1 > bits.length)
{
long[] nd = new long[lastElt + 1];
System.arraycopy(bits, 0, nd, 0, bits.length);
bits = nd;
}
}
// The actual bits.
private long[] bits;
}
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