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Diffstat (limited to 'src/java/jogamp/common/util/Int32Bitfield.java')
| -rw-r--r-- | src/java/jogamp/common/util/Int32Bitfield.java | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/java/jogamp/common/util/Int32Bitfield.java b/src/java/jogamp/common/util/Int32Bitfield.java new file mode 100644 index 0000000..7b55a59 --- /dev/null +++ b/src/java/jogamp/common/util/Int32Bitfield.java @@ -0,0 +1,163 @@ +/** + * 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 boolean put(final int bitnum, final boolean bit) throws IndexOutOfBoundsException { + check(UNIT_SIZE, bitnum); + final int m = 1 << bitnum; + final boolean prev = 0 != ( storage & m ) ; + if( prev != bit ) { + if( bit ) { + storage |= m; + } else { + storage &= ~m; + } + } + return prev; + } + @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); + } +} |