/* Copyright (c) 2001-2009, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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*/
package org.hsqldb.lib;
import java.util.NoSuchElementException;
/**
* A deque of long value. Implementation based on HsqlDeque class.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 1.9.0
* @since 1.9.0
*/
public class LongDeque {
private long[] list;
private int firstindex = 0; // index of first list element
private int endindex = 0; // index of last list element + 1
protected int elementCount;
// can grow to fill list
// if elementCount == 0 then firstindex == endindex
private static final int DEFAULT_INITIAL_CAPACITY = 10;
public LongDeque() {
list = new long[DEFAULT_INITIAL_CAPACITY];
}
public int size() {
return elementCount;
}
public boolean isEmpty() {
return elementCount == 0;
}
public long getFirst() throws NoSuchElementException {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return list[firstindex];
}
public long getLast() throws NoSuchElementException {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return list[endindex - 1];
}
public long get(int i) throws IndexOutOfBoundsException {
int index = getInternalIndex(i);
return list[index];
}
public long removeFirst() throws NoSuchElementException {
if (elementCount == 0) {
throw new NoSuchElementException();
}
long value = list[firstindex];
list[firstindex] = 0;
firstindex++;
elementCount--;
if (elementCount == 0) {
firstindex = endindex = 0;
} else if (firstindex == list.length) {
firstindex = 0;
}
return value;
}
public long removeLast() throws NoSuchElementException {
if (elementCount == 0) {
throw new NoSuchElementException();
}
endindex--;
long value = list[endindex];
list[endindex] = 0;
elementCount--;
if (elementCount == 0) {
firstindex = endindex = 0;
} else if (endindex == 0) {
endindex = list.length;
}
return value;
}
public boolean add(long value) {
resetCapacity();
if (endindex == list.length) {
endindex = 0;
}
list[endindex] = value;
elementCount++;
endindex++;
return true;
}
public boolean addLast(long value) {
return add(value);
}
public boolean addFirst(long value) {
resetCapacity();
firstindex--;
if (firstindex < 0) {
firstindex = list.length - 1;
if (endindex == 0) {
endindex = list.length;
}
}
list[firstindex] = value;
elementCount++;
return true;
}
public void clear() {
if (elementCount == 0) {
return;
}
firstindex = endindex = elementCount = 0;
for (int i = 0; i < list.length; i++) {
list[i] = 0;
}
}
public int indexOf(long value) {
for (int i = 0; i < elementCount; i++) {
int index = firstindex + i;
if (index >= list.length) {
index -= list.length;
}
if (list[index] == value) {
return i;
}
}
return -1;
}
public long remove(final int index) {
int target = getInternalIndex(index);
long value = list[target];
if (target == firstindex) {
list[firstindex] = 0;
firstindex++;
if (firstindex == list.length) {
firstindex = 0;
}
} else if (target > firstindex) {
System.arraycopy(list, firstindex, list, firstindex + 1,
target - firstindex);
list[firstindex] = 0;
firstindex++;
if (firstindex == list.length) {
firstindex = 0;
}
} else {
System.arraycopy(list, target + 1, list, target,
endindex - target - 1);
endindex--;
list[endindex] = 0;
if (endindex == 0) {
endindex = list.length;
}
}
elementCount--;
if (elementCount == 0) {
firstindex = endindex = 0;
}
return value;
}
private int getInternalIndex(int i) throws IndexOutOfBoundsException {
if (i < 0 || i >= elementCount) {
throw new IndexOutOfBoundsException();
}
int index = firstindex + i;
if (index >= list.length) {
index -= list.length;
}
return index;
}
private void resetCapacity() {
if (elementCount < list.length) {
return;
}
long[] newList = new long[list.length * 2];
System.arraycopy(list, firstindex, newList, firstindex,
list.length - firstindex);
if (endindex <= firstindex) {
System.arraycopy(list, 0, newList, list.length, endindex);
endindex = list.length + endindex;
}
list = newList;
}
}