shz.core.queue.a.LArrayQueue Maven / Gradle / Ivy
package shz.core.queue.a;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* 元素类型为E基于循环动态数组的队列
*
* 24+[8+E(类型字节)]*n(n为元素个数)=es
*
* B=56+8*n+(E*n+对齐填充)
*/
@SuppressWarnings("unchecked")
public class LArrayQueue extends ArrayQueue {
protected E[] es;
protected LArrayQueue(int capacity) {
super(capacity);
es = (E[]) new Object[capacity];
}
public static LArrayQueue of(int capacity) {
return new LArrayQueue<>(capacity);
}
public static LArrayQueue of() {
return of(DEFAULT_CAPACITY);
}
@Override
protected final E get(int i) {
return es[i];
}
@Override
protected final void resize(int capacity) {
E[] temp = (E[]) new Object[capacity];
for (int i = 0; i < size; ++i) temp[i] = es[(i + head) % this.capacity];
this.capacity = capacity;
head = 0;
tail = size;
es = temp;
}
@Override
protected final void setNull(int i) {
es[i] = null;
}
public final void offer(E e) {
beforeOffer();
es[tail] = e;
afterOffer();
}
public final E poll() {
E e = es[head];
afterPoll();
return e;
}
public final E head() {
return es[head];
}
public final E tail() {
return es[tail == 0 ? capacity - 1 : tail - 1];
}
public final List toList() {
if (size == 0) return Collections.emptyList();
List result = new ArrayList<>(size);
int current = head;
while (current != tail) {
result.add(es[current]);
current = (current + 1) % capacity;
}
return result;
}
}