| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| 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 $Id$ |
| */ |
| 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(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(int,int) |
| * @param holder the int data containing the bits we're interested |
| * in |
| * @return the selected bits, shifted right appropriately |
| */ |
| public int getValue(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(short,short) |
| * @param holder the short data containing the bits we're |
| * interested in |
| * @return the selected bits, shifted right appropriately |
| */ |
| public short getShortValue(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(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(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(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(int holder) { |
| return (holder & _mask) == _mask; |
| } |
| |
| /** |
| * <p>Replaces the bits with new values.</p> |
| * |
| * @see #getValue(int) |
| * @param holder the int 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 int setValue(int holder, int value) { |
| return (holder & ~_mask) | ((value << _shift_count) & _mask); |
| } |
| |
| /** |
| * <p>Replaces the bits with new values.</p> |
| * |
| * @see #getShortValue(short) |
| * @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(short holder, 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(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(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(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(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(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(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(int holder, 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(short holder, 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(byte holder, boolean flag) { |
| return flag ? setByte(holder) : clearByte(holder); |
| } |
| |
| } |
