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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 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(bitSize-length+1, lowBitnum);
final int u = lowBitnum >>> UNIT_SHIFT;
final int left = 32 - ( lowBitnum - ( u << UNIT_SHIFT ) ); // remaining bits of first chunk storage
if( 32 == left ) {
// fast path
final int m = ( 1 << length ) - 1;
return m & storage[u];
} else {
// slow path
final int l = Math.min(length, left); // length of first chunk
final int m = ( 1 << l ) - 1; // mask of first chunk
final int d = m & ( storage[u] >>> lowBitnum );
final int l2 = length - l; // length of last chunk
if( l2 > 0 ) {
final int m2 = ( 1 << l2 ) - 1; // mask of last chunk
return d | ( ( m2 & storage[u+1] ) << l );
} else {
return d;
}
}
}
@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(bitSize-length+1, lowBitnum);
final int u = lowBitnum >>> UNIT_SHIFT;
final int left = 32 - ( lowBitnum - ( u << UNIT_SHIFT ) ); // remaining bits of first chunk storage
if( 32 == left ) {
// fast path
final int m = ( 1 << length ) - 1; // mask of chunk
storage[u] = ( ( ~m ) & storage[u] ) // 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
final int m = ( 1 << l ) - 1; // mask of first chunk
storage[u] = ( ( ~( m << lowBitnum ) ) & storage[u] ) // keep non-written storage bits
| ( ( m & data ) << lowBitnum ); // overwrite storage w/ used data bits
final int l2 = length - l; // length of last chunk
if( l2 > 0 ) {
final int m2 = ( 1 << l2 ) - 1; // mask of last chunk
storage[u] = ( ( ~m2 ) & storage[u+1] ) // keep non-written storage bits
| ( m2 & ( data >>> l ) ); // 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(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
return 0 != ( storage[u] & ( 1 << b ) ) ;
}
@Override
public final void put(final int bitnum, final boolean bit) throws IndexOutOfBoundsException {
check(bitSize, bitnum);
final int u = bitnum >>> UNIT_SHIFT;
final int b = bitnum - ( u << UNIT_SHIFT );
final int m = 1 << b;
if( bit ) {
storage[u] |= m;
} else {
storage[u] &= ~m;
}
}
@Override
public final void set(final int bitnum) throws IndexOutOfBoundsException {
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 IndexOutOfBoundsException {
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 boolean copy(final int srcBitnum, final int dstBitnum) throws IndexOutOfBoundsException {
check(bitSize, srcBitnum);
check(bitSize, dstBitnum);
final boolean bit;
// get
{
final int u = srcBitnum >>> UNIT_SHIFT;
final int b = srcBitnum - ( u << UNIT_SHIFT );
bit = 0 != ( storage[u] & ( 1 << b ) ) ;
}
// put
final int u = dstBitnum >>> UNIT_SHIFT;
final int b = dstBitnum - ( u << UNIT_SHIFT );
final int m = 1 << b;
if( bit ) {
storage[u] |= m;
} else {
storage[u] &= ~m;
}
return bit;
}
@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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