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/**
* Copyright 2015 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package jogamp.common.util;
import com.jogamp.common.util.Bitfield;
/**
* Simple bitfield interface for efficient storage access in O(1).
* <p>
* Implementation uses a 32bit integer array for storage.
* </p>
*/
public class Int32ArrayBitfield implements Bitfield {
private static final int UNIT_SHIFT = 5;
private final int[] storage;
private final int bitSize;
/**
* @param storageBitSize
*/
public Int32ArrayBitfield(final int storageBitSize) {
final int units = Math.max(1, ( storageBitSize + 7 ) >>> UNIT_SHIFT);
this.storage = new int[units];
this.bitSize = units << UNIT_SHIFT;
}
@Override
public int getStorageBitSize() {
return bitSize;
}
private final void check(final int limit, final int bitnum) throws ArrayIndexOutOfBoundsException {
if( 0 > bitnum || bitnum >= limit ) {
throw new ArrayIndexOutOfBoundsException("Bitnum should be within [0.."+(limit-1)+"], but is "+bitnum);
}
}
@Override
public final int getInt32(final int rightBitnum) throws ArrayIndexOutOfBoundsException {
check(bitSize-31, rightBitnum);
if( 0 == rightBitnum % 32 ) {
// fast path
return storage[rightBitnum >>> UNIT_SHIFT];
} else {
// slow path
throw new UnsupportedOperationException("todo: non-32bit alignment");
}
}
@Override
public final void putInt32(final int rightBitnum, final int mask) throws ArrayIndexOutOfBoundsException {
check(bitSize-31, rightBitnum);
if( 0 == rightBitnum % 32 ) {
// fast path
storage[rightBitnum >>> UNIT_SHIFT] = mask;
} else {
// slow path
throw new UnsupportedOperationException("todo: non-32bit alignment");
}
}
@Override
public final boolean get(final int bitnum) throws ArrayIndexOutOfBoundsException {
check(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
return 0 != ( storage[u] & ( 1 << b ) ) ;
}
@Override
public final boolean put(final int bitnum, final boolean bit) throws ArrayIndexOutOfBoundsException {
check(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
final int m = 1 << b;
final boolean prev = 0 != ( storage[u] & m ) ;
if( prev != bit ) {
if( bit ) {
storage[u] |= m;
} else {
storage[u] &= ~m;
}
}
return prev;
}
@Override
public final void set(final int bitnum) throws ArrayIndexOutOfBoundsException {
check(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
final int m = 1 << b;
storage[u] |= m;
}
@Override
public final void clear (final int bitnum) throws ArrayIndexOutOfBoundsException {
check(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
final int m = 1 << b;
storage[u] &= ~m;
}
@Override
public int getBitCount() {
int c = 0;
for(int i = storage.length-1; i>=0; i--) {
c += Bitfield.Util.getBitCount(storage[i]);
}
return c;
}
}
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