/*
* Copyright 2005-2010 Roger Kapsi
*
* Licensed 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.ardverk.collection;
import java.io.Serializable;
/**
* A {@link KeyAnalyzer} for {@link Character}s.
*/
public class CharacterKeyAnalyzer extends AbstractKeyAnalyzer<Character>
implements Serializable {
private static final long serialVersionUID = 5267330596735811400L;
/**
* A {@link CharacterKeyAnalyzer} that uses all bits (16) of a {@code char}.
*/
public static final CharacterKeyAnalyzer CHAR = new CharacterKeyAnalyzer(Character.SIZE);
/**
* A {@link CharacterKeyAnalyzer} that uses only the lower 8bits of a {@code char}.
*/
public static final CharacterKeyAnalyzer BYTE = new CharacterKeyAnalyzer(Byte.SIZE);
@Deprecated
public static final CharacterKeyAnalyzer INSTANCE = CHAR;
private final int size;
private final int msb;
private CharacterKeyAnalyzer(int size) {
this(size, 1 << size-1);
}
private CharacterKeyAnalyzer(int size, int msb) {
this.size = size;
this.msb = msb;
}
/**
* Returns a bit mask where the given bit is set
*/
private int mask(int bit) {
return msb >>> bit;
}
private char valueOf(Character ch) {
char value = ch.charValue();
if (size == Byte.SIZE) {
value &= 0xFF;
}
return value;
}
public int lengthInBits(Character key) {
return size;
}
public boolean isBitSet(Character key, int bitIndex) {
return (key & mask(bitIndex)) != 0;
}
public int bitIndex(Character key, Character otherKey) {
char ch1 = valueOf(key);
char ch2 = valueOf(otherKey);
if (ch1 == 0) {
return NULL_BIT_KEY;
}
if (ch1 != ch2) {
int xor = ch1 ^ ch2;
for (int i = 0; i < size; i++) {
if ((xor & mask(i)) != 0) {
return i;
}
}
}
return KeyAnalyzer.EQUAL_BIT_KEY;
}
public boolean isPrefix(Character key, Character prefix) {
return key.equals(prefix);
}
}