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/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* 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 com.badlogic.gdx.utils;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import com.badlogic.gdx.math.MathUtils;
/** A resizable, ordered or unordered array of objects. If unordered, this class avoids a memory copy when removing elements (the
* last element is moved to the removed element's position).
* @author Nathan Sweet */
public class Array implements Iterable {
/** Provides direct access to the underlying array. If the Array's generic type is not Object, this field may only be accessed
* if the {@link Array#Array(boolean, int, Class)} constructor was used. */
public T[] items;
public int size;
public boolean ordered;
private ArrayIterator iterator;
/** Creates an ordered array with a capacity of 16. */
public Array () {
this(true, 16);
}
/** Creates an ordered array with the specified capacity. */
public Array (int capacity) {
this(true, capacity);
}
/** @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
* memory copy.
* @param capacity Any elements added beyond this will cause the backing array to be grown. */
public Array (boolean ordered, int capacity) {
this.ordered = ordered;
items = (T[])new Object[capacity];
}
/** Creates a new array with {@link #items} of the specified type.
* @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
* memory copy.
* @param capacity Any elements added beyond this will cause the backing array to be grown. */
public Array (boolean ordered, int capacity, Class arrayType) {
this.ordered = ordered;
items = (T[])java.lang.reflect.Array.newInstance(arrayType, capacity);
}
/** Creates an ordered array with {@link #items} of the specified type and a capacity of 16. */
public Array (Class arrayType) {
this(false, 16, arrayType);
}
/** Creates a new array containing the elements in the specified array. The new array will have the same type of backing array
* and will be ordered if the specified array is ordered. The capacity is set to the number of elements, so any subsequent
* elements added will cause the backing array to be grown. */
public Array (Array array) {
this(array.ordered, array.size, (Class)array.items.getClass().getComponentType());
size = array.size;
System.arraycopy(array.items, 0, items, 0, size);
}
/** Creates a new ordered array containing the elements in the specified array. The new array will have the same type of backing
* array. The capacity is set to the number of elements, so any subsequent elements added will cause the backing array to be
* grown. */
public Array (T[] array) {
this(true, array);
}
/** Creates a new array containing the elements in the specified array. The new array will have the same type of backing array.
* The capacity is set to the number of elements, so any subsequent elements added will cause the backing array to be grown.
* @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
* memory copy. */
public Array (boolean ordered, T[] array) {
this(ordered, array.length, (Class)array.getClass().getComponentType());
size = array.length;
System.arraycopy(array, 0, items, 0, size);
}
public void add (T value) {
T[] items = this.items;
if (size == items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
items[size++] = value;
}
public void addAll (Array array) {
addAll(array, 0, array.size);
}
public void addAll (Array array, int offset, int length) {
if (offset + length > array.size)
throw new IllegalArgumentException("offset + length must be <= size: " + offset + " + " + length + " <= " + array.size);
addAll((T[])array.items, offset, length);
}
public void addAll (T[] array) {
addAll(array, 0, array.length);
}
public void addAll (T[] array, int offset, int length) {
T[] items = this.items;
int sizeNeeded = size + length;
if (sizeNeeded > items.length) items = resize(Math.max(8, (int)(sizeNeeded * 1.75f)));
System.arraycopy(array, offset, items, size, length);
size += length;
}
public T get (int index) {
if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
return items[index];
}
public void set (int index, T value) {
if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
items[index] = value;
}
public void insert (int index, T value) {
T[] items = this.items;
if (size == items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
if (ordered)
System.arraycopy(items, index, items, index + 1, size - index);
else
items[size] = items[index];
size++;
items[index] = value;
}
/** @param identity If true, == comparison will be used. If false, .equals() comaparison will be used. */
public boolean contains (T value, boolean identity) {
T[] items = this.items;
int i = size - 1;
if (identity || value == null) {
while (i >= 0)
if (items[i--] == value) return true;
} else {
while (i >= 0)
if (value.equals(items[i--])) return true;
}
return false;
}
public int indexOf (T value, boolean identity) {
T[] items = this.items;
if (identity || value == null) {
for (int i = 0, n = size; i < n; i++)
if (items[i] == value) return i;
} else {
for (int i = 0, n = size; i < n; i++)
if (value.equals(items[i])) return i;
}
return -1;
}
public boolean removeValue (T value, boolean identity) {
T[] items = this.items;
if (identity || value == null) {
for (int i = 0, n = size; i < n; i++) {
if (items[i] == value) {
removeIndex(i);
return true;
}
}
} else {
for (int i = 0, n = size; i < n; i++) {
if (value.equals(items[i])) {
removeIndex(i);
return true;
}
}
}
return false;
}
/** Removes and returns the item at the specified index. */
public T removeIndex (int index) {
if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
T[] items = this.items;
T value = (T)items[index];
size--;
if (ordered)
System.arraycopy(items, index + 1, items, index, size - index);
else
items[index] = items[size];
items[size] = null;
return value;
}
/** Removes and returns the last item. */
public T pop () {
--size;
T item = items[size];
items[size] = null;
return item;
}
/** Returns the last item. */
public T peek () {
return items[size - 1];
}
public void clear () {
T[] items = this.items;
for (int i = 0, n = size; i < n; i++)
items[i] = null;
size = 0;
}
/** Reduces the size of the backing array to the size of the actual items. This is useful to release memory when many items have
* been removed, or if it is known that more items will not be added. */
public void shrink () {
resize(size);
}
/** Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many
* items to avoid multiple backing array resizes.
* @return {@link #items} */
public T[] ensureCapacity (int additionalCapacity) {
int sizeNeeded = size + additionalCapacity;
if (sizeNeeded >= items.length) resize(Math.max(8, sizeNeeded));
return items;
}
protected T[] resize (int newSize) {
T[] items = this.items;
T[] newItems = (T[])java.lang.reflect.Array.newInstance(items.getClass().getComponentType(), newSize);
System.arraycopy(items, 0, newItems, 0, Math.min(items.length, newItems.length));
this.items = newItems;
return newItems;
}
/** Sorts this array. The array elements must implement {@link Comparable}. This method is not thread safe (uses
* {@link Sort#instance()}). */
public void sort () {
Sort.instance().sort(items, 0, size);
}
/** Sorts the array. This method is not thread safe (uses {@link Sort#instance()}). */
public void sort (Comparator comparator) {
Sort.instance().sort(items, comparator, 0, size);
}
public void reverse () {
for (int i = 0, lastIndex = size - 1, n = size / 2; i < n; i++) {
int ii = lastIndex - i;
T temp = items[i];
items[i] = items[ii];
items[ii] = temp;
}
}
public void shuffle () {
for (int i = size - 1; i >= 0; i--) {
int ii = MathUtils.random(i);
T temp = items[i];
items[i] = items[ii];
items[ii] = temp;
}
}
/** Returns an iterator for the items in the array. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link ArrayIterator} constructor for nested or multithreaded iteration. */
public Iterator iterator () {
if (iterator == null) iterator = new ArrayIterator(this);
iterator.index = 0;
return iterator;
}
/** Reduces the size of the array to the specified size. If the array is already smaller than the specified size, no action is
* taken. */
public void truncate (int newSize) {
if (size <= newSize) return;
for (int i = newSize; i < size; i++)
items[i] = null;
size = newSize;
}
/** Returns a random item from the array, or null if the array is empty. */
public T random () {
if (size == 0) return null;
return items[MathUtils.random(0, size - 1)];
}
public T[] toArray () {
return (T[])toArray(items.getClass().getComponentType());
}
public V[] toArray (Class type) {
V[] result = (V[])java.lang.reflect.Array.newInstance(type, size);
System.arraycopy(items, 0, result, 0, size);
return result;
}
public String toString () {
if (size == 0) return "[]";
T[] items = this.items;
StringBuilder buffer = new StringBuilder(32);
buffer.append('[');
buffer.append(items[0]);
for (int i = 1; i < size; i++) {
buffer.append(", ");
buffer.append(items[i]);
}
buffer.append(']');
return buffer.toString();
}
public String toString (String separator) {
if (size == 0) return "";
T[] items = this.items;
StringBuilder buffer = new StringBuilder(32);
buffer.append(items[0]);
for (int i = 1; i < size; i++) {
buffer.append(separator);
buffer.append(items[i]);
}
return buffer.toString();
}
static public class ArrayIterator implements Iterator {
private final Array array;
int index;
public ArrayIterator (Array array) {
this.array = array;
}
public boolean hasNext () {
return index < array.size;
}
public T next () {
if (index >= array.size) throw new NoSuchElementException(String.valueOf(index));
return array.items[index++];
}
public void remove () {
index--;
array.removeIndex(index);
}
public void reset () {
index = 0;
}
}
static public class ArrayIterable implements Iterable {
private ArrayIterator iterator;
public ArrayIterable (Array array) {
iterator = new ArrayIterator(array);
}
@Override
public Iterator iterator () {
iterator.reset();
return iterator;
}
}
}
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