io.questdb.std.LowerCaseCharSequenceHashSet Maven / Gradle / Ivy
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*
* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2020 QuestDB
*
* 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 io.questdb.std;
public class LowerCaseCharSequenceHashSet extends AbstractLowerCaseCharSequenceHashSet {
private static final int MIN_INITIAL_CAPACITY = 16;
public LowerCaseCharSequenceHashSet() {
this(MIN_INITIAL_CAPACITY);
}
private LowerCaseCharSequenceHashSet(int initialCapacity) {
this(initialCapacity, 0.4);
}
private LowerCaseCharSequenceHashSet(int initialCapacity, double loadFactor) {
super(initialCapacity, loadFactor);
clear();
}
/**
* Adds key to hash set preserving key uniqueness.
*
* @param key immutable sequence of characters.
* @return false if key is already in the set and true otherwise.
*/
public boolean add(CharSequence key) {
int index = keyIndex(key);
if (index < 0) {
return false;
}
addAt(index, key);
return true;
}
public void addAt(int index, CharSequence key) {
keys[index] = key;
if (--free < 1) {
rehash();
}
}
public boolean contains(CharSequence key) {
return keyIndex(key) < 0;
}
public CharSequence keyAt(int index) {
return keys[-index - 1];
}
@Override
protected void erase(int index) {
keys[index] = noEntryKey;
}
@Override
protected void move(int from, int to) {
keys[to] = keys[from];
erase(from);
}
private void rehash() {
int newCapacity = capacity * 2;
final int size = size();
free = capacity = newCapacity;
int len = Numbers.ceilPow2((int) (newCapacity / loadFactor));
CharSequence[] newKeys = new CharSequence[len];
CharSequence[] oldKeys = keys;
mask = len - 1;
this.keys = newKeys;
free -= size;
for (int i = 0, n = oldKeys.length; i < n; i++) {
CharSequence key = oldKeys[i];
if (key != null) {
keys[keyIndex(key)] = key;
}
}
}
}