- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2002-2003 The Apache Software Foundation. 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.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowledgement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgement may appear in the software itself,
- * if and wherever such third-party acknowledgements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE APACHE SOFTWARE FOUNDATION OR
- * ITS 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.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
- package org.apache.commons.lang;
-
- /**
- * <p>Operations on bit-mapped fields.</p>
- *
- * @author Apache Jakarta POI
- * @author Scott Sanders (sanders at apache dot org)
- * @author Marc Johnson (mjohnson at apache dot org)
- * @author Andrew C. Oliver (acoliver at apache dot org)
- * @author Stephen Colebourne
- * @author Pete Gieser
- * @author Gary Gregory
- * @since 2.0
- * @version $Id: BitField.java,v 1.2 2003/08/22 16:57:04 ggregory Exp $
- */
- public class BitField {
-
- private final int _mask;
- private final int _shift_count;
-
- /**
- * <p>Creates a BitField instance.</p>
- *
- * @param mask the mask specifying which bits apply to this
- * BitField. Bits that are set in this mask are the bits
- * that this BitField operates on
- */
- public BitField(final int mask) {
- _mask = mask;
- int count = 0;
- int bit_pattern = mask;
-
- if (bit_pattern != 0) {
- while ((bit_pattern & 1) == 0) {
- count++;
- bit_pattern >>= 1;
- }
- }
- _shift_count = count;
- }
-
- /**
- * <p>Obtains the value for the specified BitField, appropriately
- * shifted right.</p>
- *
- * <p>Many users of a BitField will want to treat the specified
- * bits as an int value, and will not want to be aware that the
- * value is stored as a BitField (and so shifted left so many
- * bits).</p>
- *
- * @see #setValue
- * @param holder the int data containing the bits we're interested
- * in
- * @return the selected bits, shifted right appropriately
- */
- public int getValue(final int holder) {
- return getRawValue(holder) >> _shift_count;
- }
-
- /**
- * <p>Obtains the value for the specified BitField, appropriately
- * shifted right, as a short.</p>
- *
- * <p>Many users of a BitField will want to treat the specified
- * bits as an int value, and will not want to be aware that the
- * value is stored as a BitField (and so shifted left so many
- * bits).</p>
- *
- * @see #setShortValue
- * @param holder the short data containing the bits we're
- * interested in
- * @return the selected bits, shifted right appropriately
- */
- public short getShortValue(final short holder) {
- return (short) getValue(holder);
- }
-
- /**
- * <p>Obtains the value for the specified BitField, unshifted.</p>
- *
- * @param holder the int data containing the bits we're
- * interested in
- * @return the selected bits
- */
- public int getRawValue(final int holder) {
- return (holder & _mask);
- }
-
- /**
- * <p>Obtains the value for the specified BitField, unshifted.</p>
- *
- * @param holder the short data containing the bits we're
- * interested in
- * @return the selected bits
- */
- public short getShortRawValue(final short holder) {
- return (short) getRawValue(holder);
- }
-
- /**
- * <p>Returns whether the field is set or not.</p>
- *
- * <p>This is most commonly used for a single-bit field, which is
- * often used to represent a boolean value; the results of using
- * it for a multi-bit field is to determine whether *any* of its
- * bits are set.</p>
- *
- * @param holder the int data containing the bits we're interested
- * in
- * @return <code>true</code> if any of the bits are set,
- * else <code>false</code>
- */
- public boolean isSet(final int holder) {
- return (holder & _mask) != 0;
- }
-
- /**
- * <p>Returns whether all of the bits are set or not.</p>
- *
- * <p>This is a stricter test than {@link #isSet(int)},
- * in that all of the bits in a multi-bit set must be set
- * for this method to return <code>true</code>.</p>
- *
- * @param holder the int data containing the bits we're
- * interested in
- * @return <code>true</code> if all of the bits are set,
- * else <code>false</code>
- */
- public boolean isAllSet(final int holder) {
- return (holder & _mask) == _mask;
- }
-
- /**
- * <p>Replaces the bits with new values.</p>
- *
- * @see #getValue
- * @param holder the int data containint the bits we're
- * interested in
- * @param value the new value for the specified bits
- * @return the value of holder with the bits from the value
- * parameter replacing the old bits
- */
- public int setValue(final int holder, final int value) {
- return (holder & ~_mask) | ((value << _shift_count) & _mask);
- }
-
- /**
- * <p>Replaces the bits with new values.</p>
- *
- * @see #getShortValue
- * @param holder the short data containing the bits we're
- * interested in
- * @param value the new value for the specified bits
- * @return the value of holder with the bits from the value
- * parameter replacing the old bits
- */
- public short setShortValue(final short holder, final short value) {
- return (short) setValue(holder, value);
- }
-
- /**
- * <p>Clears the bits.</p>
- *
- * @param holder the int data containing the bits we're
- * interested in
- * @return the value of holder with the specified bits cleared
- * (set to <code>0</code>)
- */
- public int clear(final int holder) {
- return holder & ~_mask;
- }
-
- /**
- * <p>Clears the bits.</p>
- *
- * @param holder the short data containing the bits we're
- * interested in
- * @return the value of holder with the specified bits cleared
- * (set to <code>0</code>)
- */
- public short clearShort(final short holder) {
- return (short) clear(holder);
- }
-
- /**
- * <p>Clears the bits.</p>
- *
- * @param holder the byte data containing the bits we're
- * interested in
- *
- * @return the value of holder with the specified bits cleared
- * (set to <code>0</code>)
- */
- public byte clearByte(final byte holder) {
- return (byte) clear(holder);
- }
-
- /**
- * <p>Sets the bits.</p>
- *
- * @param holder the int data containing the bits we're
- * interested in
- * @return the value of holder with the specified bits set
- * to <code>1</code>
- */
- public int set(final int holder) {
- return holder | _mask;
- }
-
- /**
- * <p>Sets the bits.</p>
- *
- * @param holder the short data containing the bits we're
- * interested in
- * @return the value of holder with the specified bits set
- * to <code>1</code>
- */
- public short setShort(final short holder) {
- return (short) set(holder);
- }
-
- /**
- * <p>Sets the bits.</p>
- *
- * @param holder the byte data containing the bits we're
- * interested in
- *
- * @return the value of holder with the specified bits set
- * to <code>1</code>
- */
- public byte setByte(final byte holder) {
- return (byte) set(holder);
- }
-
- /**
- * <p>Sets a boolean BitField.</p>
- *
- * @param holder the int data containing the bits we're
- * interested in
- * @param flag indicating whether to set or clear the bits
- * @return the value of holder with the specified bits set or
- * cleared
- */
- public int setBoolean(final int holder, final boolean flag) {
- return flag ? set(holder) : clear(holder);
- }
-
- /**
- * <p>Sets a boolean BitField.</p>
- *
- * @param holder the short data containing the bits we're
- * interested in
- * @param flag indicating whether to set or clear the bits
- * @return the value of holder with the specified bits set or
- * cleared
- */
- public short setShortBoolean(final short holder, final boolean flag) {
- return flag ? setShort(holder) : clearShort(holder);
- }
-
- /**
- * <p>Sets a boolean BitField.</p>
- *
- * @param holder the byte data containing the bits we're
- * interested in
- * @param flag indicating whether to set or clear the bits
- * @return the value of holder with the specified bits set or
- * cleared
- */
- public byte setByteBoolean(final byte holder, final boolean flag) {
- return flag ? setByte(holder) : clearByte(holder);
- }
-
- }