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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 one 32bit integer field for storage.
* </p>
*/
public class Int32Bitfield implements Bitfield {
/** Unit size in bits, here 32 bits for one int unit. */
private static final int UNIT_SIZE = 32;
private int storage;
public Int32Bitfield() {
this.storage = 0;
}
@Override
public int size() {
return UNIT_SIZE;
}
@Override
public final void clearField(final boolean bit) {
if( bit ) {
storage = Bitfield.UNSIGNED_INT_MAX_VALUE;
} else {
storage = 0;
}
}
private static final void check(final int size, final int bitnum) throws IndexOutOfBoundsException {
if( 0 > bitnum || bitnum >= size ) {
throw new IndexOutOfBoundsException("Bitnum should be within [0.."+(size-1)+"], but is "+bitnum);
}
}
@Override
public final int get32(final int lowBitnum, final int length) throws IndexOutOfBoundsException {
if( 0 > length || length > 32 ) {
throw new IndexOutOfBoundsException("length should be within [0..32], but is "+length);
}
check(UNIT_SIZE-length+1, lowBitnum);
final int left = 32 - lowBitnum; // remaining bits of first chunk
if( 32 == left ) {
// fast path
final int m = Util.getBitMask(length); // mask of chunk
return m & storage;
} else {
// slow path
final int l = Math.min(length, left); // length of first chunk < 32
final int m = ( 1 << l ) - 1; // mask of first chunk
return m & ( storage >>> lowBitnum );
}
}
@Override
public final void put32(final int lowBitnum, final int length, final int data) throws IndexOutOfBoundsException {
if( 0 > length || length > 32 ) {
throw new IndexOutOfBoundsException("length should be within [0..32], but is "+length);
}
check(UNIT_SIZE-length+1, lowBitnum);
final int left = 32 - lowBitnum; // remaining bits of first chunk storage
if( 32 == left ) {
// fast path
final int m = Util.getBitMask(length); // mask of chunk
storage = ( ( ~m ) & storage ) // keep non-written storage bits
| ( m & data ); // overwrite storage w/ used data bits
} else {
// slow path
final int l = Math.min(length, left); // length of first chunk < 32
final int m = ( 1 << l ) - 1; // mask of first chunk
storage = ( ( ~( m << lowBitnum ) ) & storage ) // keep non-written storage bits
| ( ( m & data ) << lowBitnum ); // overwrite storage w/ used data bits
}
}
@Override
public final int copy32(final int srcBitnum, final int dstBitnum, final int length) throws IndexOutOfBoundsException {
final int data = get32(srcBitnum, length);
put32(dstBitnum, length, data);
return data;
}
@Override
public final boolean get(final int bitnum) throws IndexOutOfBoundsException {
check(UNIT_SIZE, bitnum);
return 0 != ( storage & ( 1 << bitnum ) ) ;
}
@Override
public final void put(final int bitnum, final boolean bit) throws IndexOutOfBoundsException {
check(UNIT_SIZE, bitnum);
final int m = 1 << bitnum;
if( bit ) {
storage |= m;
} else {
storage &= ~m;
}
}
@Override
public final void set(final int bitnum) throws IndexOutOfBoundsException {
check(UNIT_SIZE, bitnum);
final int m = 1 << bitnum;
storage |= m;
}
@Override
public final void clear (final int bitnum) throws IndexOutOfBoundsException {
check(UNIT_SIZE, bitnum);
final int m = 1 << bitnum;
storage &= ~m;
}
@Override
public final boolean copy(final int srcBitnum, final int dstBitnum) throws IndexOutOfBoundsException {
check(UNIT_SIZE, srcBitnum);
check(UNIT_SIZE, dstBitnum);
// get
final boolean bit = 0 != ( storage & ( 1 << srcBitnum ) ) ;
// put
final int m = 1 << dstBitnum;
if( bit ) {
storage |= m;
} else {
storage &= ~m;
}
return bit;
}
@Override
public int bitCount() {
return Bitfield.Util.bitCount(storage);
}
}
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