com.phloc.commons.lang.BitSetHelper Maven / Gradle / Ivy
/**
* Copyright (C) 2006-2015 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* Licensed 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 com.phloc.commons.lang;
import java.util.BitSet;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import com.phloc.commons.CGlobal;
import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.annotations.PresentForCodeCoverage;
/**
* Helper class to work with bit sets.
*
* @author Philip Helger
*/
@Immutable
public final class BitSetHelper
{
@PresentForCodeCoverage
@SuppressWarnings ("unused")
private static final BitSetHelper s_aInstance = new BitSetHelper ();
private BitSetHelper ()
{}
/**
* Convert the passed byte value to an bit set of size 8.
*
* @param nValue
* The value to be converted to a bit set.
* @return The non-null bit set.
*/
@Nonnull
public static BitSet createBitSet (final byte nValue)
{
final BitSet ret = new BitSet (CGlobal.BITS_PER_BYTE);
for (int i = 0; i < CGlobal.BITS_PER_BYTE; ++i)
ret.set (i, ((nValue >> i) & 1) == 1);
return ret;
}
/**
* Convert the passed short value to an bit set of size 16.
*
* @param nValue
* The value to be converted to a bit set.
* @return The non-null bit set.
*/
@Nonnull
public static BitSet createBitSet (final short nValue)
{
final BitSet ret = new BitSet (CGlobal.BITS_PER_SHORT);
for (int i = 0; i < CGlobal.BITS_PER_SHORT; ++i)
ret.set (i, ((nValue >> i) & 1) == 1);
return ret;
}
/**
* Convert the passed int value to an bit set of size 32.
*
* @param nValue
* The value to be converted to a bit set.
* @return The non-null bit set.
*/
@Nonnull
public static BitSet createBitSet (final int nValue)
{
final BitSet ret = new BitSet (CGlobal.BITS_PER_INT);
for (int i = 0; i < CGlobal.BITS_PER_INT; ++i)
ret.set (i, ((nValue >> i) & 1) == 1);
return ret;
}
/**
* Convert the passed long value to an bit set of size 64.
*
* @param nValue
* The value to be converted to a bit set.
* @return The non-null bit set.
*/
@Nonnull
public static BitSet createBitSet (final long nValue)
{
final BitSet ret = new BitSet (CGlobal.BITS_PER_LONG);
for (int i = 0; i < CGlobal.BITS_PER_LONG; ++i)
ret.set (i, ((nValue >> i) & 1) == 1);
return ret;
}
/**
* Extract the int representation of the passed bit set. To avoid loss of
* data, the bit set may not have more than 32 bits.
*
* @param aBS
* The bit set to extract the value from. May not be null.
* @return The extracted value. May be negative if the bit set has 32
* elements, the highest order bit is set.
*/
public static int getExtractedIntValue (@Nonnull final BitSet aBS)
{
ValueEnforcer.notNull (aBS, "BitSet");
final int nMax = aBS.length ();
if (nMax > CGlobal.BITS_PER_INT)
throw new IllegalArgumentException ("Can extract only up to " + CGlobal.BITS_PER_INT + " bits");
int ret = 0;
for (int i = nMax - 1; i >= 0; --i)
{
ret <<= 1;
if (aBS.get (i))
ret += CGlobal.BIT_SET;
}
return ret;
}
/**
* Extract the long representation of the passed bit set. To avoid loss of
* data, the bit set may not have more than 64 bits.
*
* @param aBS
* The bit set to extract the value from. May not be null.
* @return The extracted value. May be negative if the bit set has 64
* elements, the highest order bit is set.
*/
public static long getExtractedLongValue (@Nonnull final BitSet aBS)
{
ValueEnforcer.notNull (aBS, "BitSet");
final int nMax = aBS.length ();
if (nMax > CGlobal.BITS_PER_LONG)
throw new IllegalArgumentException ("Can extract only up to " + CGlobal.BITS_PER_LONG + " bits");
long ret = 0;
for (int i = nMax - 1; i >= 0; --i)
{
ret <<= 1;
if (aBS.get (i))
ret += CGlobal.BIT_SET;
}
return ret;
}
}