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Added Queue iterable, removeIndex, indexOf, removeValue.
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Tests even! What is the world coming to?
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@NathanSweet
NathanSweet committed Nov 24, 2015
1 parent 2a54be4 commit e019133
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174 changes: 171 additions & 3 deletions gdx/src/com/badlogic/gdx/utils/Queue.java
View file
Expand Up @@ -16,14 +16,16 @@

package com.badlogic.gdx.utils;

import java.util.Iterator;
import java.util.NoSuchElementException;

import com.badlogic.gdx.utils.Array.ArrayIterable;
import com.badlogic.gdx.utils.reflect.ArrayReflection;

/** A resizable, ordered array of objects with efficient add and remove at the beginning and end. Values in the backing array may
* wrap back to the beginning, making add and remove at the beginning and end O(1) (unless the backing array needs to resize when
* adding). Deque functionality is provided via {@link #removeLast()} and {@link #addFirst(Object)}. */
public class Queue<T> {
public class Queue<T> implements Iterable<T> {
/** Contains the values in the queue. Head and tail indices go in a circle around this array, wrapping at the end. */
protected T[] values;

Expand All @@ -37,6 +39,8 @@ public class Queue<T> {
/** Number of elements in the queue. */
public int size = 0;

private QueueIterable iterable;

/** Creates a new Queue which can hold 16 values without needing to resize backing array. */
public Queue () {
this(16);
Expand Down Expand Up @@ -170,6 +174,76 @@ public T removeLast () {
return result;
}

/** Returns the index of first occurrence of value in the queue, or -1 if no such value exists.
* @param identity If true, == comparison will be used. If false, .equals() comparison will be used.
* @return An index of first occurrence of value in queue or -1 if no such value exists */
public int indexOf (T value, boolean identity) {
if (size == 0) return -1;
T[] values = this.values;
int head = this.head, tail = this.tail;
if (identity || value == null) {
if (head < tail) {
for (int i = head, n = tail; i < n; i++)
if (values[i] == value) return i;
} else {
for (int i = head, n = values.length; i < n; i++)
if (values[i] == value) return i - head;
for (int i = 0, n = tail; i < n; i++)
if (values[i] == value) return i + values.length - head;
}
} else {
if (head < tail) {
for (int i = head, n = tail; i < n; i++)
if (value.equals(values[i])) return i;
} else {
for (int i = head, n = values.length; i < n; i++)
if (value.equals(values[i])) return i - head;
for (int i = 0, n = tail; i < n; i++)
if (value.equals(values[i])) return i + values.length - head;
}
}
return -1;
}

/** Removes the first instance of the specified value in the queue.
* @param identity If true, == comparison will be used. If false, .equals() comparison will be used.
* @return true if value was found and removed, false otherwise */
public boolean removeValue (T value, boolean identity) {
int index = indexOf(value, identity);
if (index == -1) return false;
removeIndex(index);
return true;
}

/** Removes and returns the item at the specified index. */
public T removeIndex (int index) {
if (index < 0) throw new IndexOutOfBoundsException("index can't be < 0: " + index);
if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);

T[] values = this.values;
int head = this.head, tail = this.tail;
index += head;
T value;
if (head < tail) { // index is between head and tail.
value = (T)values[index];
System.arraycopy(values, index + 1, values, index, tail - index);
values[tail] = null;
this.tail--;
} else if (index >= values.length) { // index is between 0 and tail.
index -= values.length;
value = (T)values[index];
System.arraycopy(values, index + 1, values, index, tail - index);
this.tail--;
} else { // index is between head and values.length.
value = (T)values[index];
System.arraycopy(values, head, values, head + 1, index - head);
values[head] = null;
this.head++;
}
size--;
return value;
}

/** Returns the first (head) item in the queue (without removing it).
* @see #addFirst(Object)
* @see #removeFirst()
Expand Down Expand Up @@ -204,8 +278,8 @@ public T last () {
* same as {@link #first()}.
* @throws IndexOutOfBoundsException when the index is negative or >= size */
public T get (int index) {
if (index < 0) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
if (index >= size) throw new IndexOutOfBoundsException("index can't be < 0: " + index);
if (index < 0) throw new IndexOutOfBoundsException("index can't be < 0: " + index);
if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
final T[] values = this.values;

int i = head + index;
Expand Down Expand Up @@ -242,6 +316,13 @@ public void clear () {
this.size = 0;
}

/** Returns an iterator for the items in the queue. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link QueueIterator} constructor for nested or multithreaded iteration. */
public Iterator<T> iterator () {
if (iterable == null) iterable = new QueueIterable(this);
return iterable.iterator();
}

public String toString () {
if (size == 0) {
return "[]";
Expand Down Expand Up @@ -308,4 +389,91 @@ public boolean equals (Object o) {
}
return true;
}

static public class QueueIterator<T> implements Iterator<T>, Iterable<T> {
private final Queue<T> queue;
private final boolean allowRemove;
int index;
boolean valid = true;

// QueueIterable<T> iterable;

public QueueIterator (Queue<T> queue) {
this(queue, true);
}

public QueueIterator (Queue<T> queue, boolean allowRemove) {
this.queue = queue;
this.allowRemove = allowRemove;
}

public boolean hasNext () {
if (!valid) {
// System.out.println(iterable.lastAcquire);
throw new GdxRuntimeException("#iterator() cannot be used nested.");
}
return index < queue.size;
}

public T next () {
if (index >= queue.size) throw new NoSuchElementException(String.valueOf(index));
if (!valid) {
// System.out.println(iterable.lastAcquire);
throw new GdxRuntimeException("#iterator() cannot be used nested.");
}
return queue.get(index++);
}

public void remove () {
if (!allowRemove) throw new GdxRuntimeException("Remove not allowed.");
index--;
queue.removeIndex(index);
}

public void reset () {
index = 0;
}

public Iterator<T> iterator () {
return this;
}
}

static public class QueueIterable<T> implements Iterable<T> {
private final Queue<T> queue;
private final boolean allowRemove;
private QueueIterator iterator1, iterator2;

// java.io.StringWriter lastAcquire = new java.io.StringWriter();

public QueueIterable (Queue<T> queue) {
this(queue, true);
}

public QueueIterable (Queue<T> queue, boolean allowRemove) {
this.queue = queue;
this.allowRemove = allowRemove;
}

public Iterator<T> iterator () {
// lastAcquire.getBuffer().setLength(0);
// new Throwable().printStackTrace(new java.io.PrintWriter(lastAcquire));
if (iterator1 == null) {
iterator1 = new QueueIterator(queue, allowRemove);
iterator2 = new QueueIterator(queue, allowRemove);
// iterator1.iterable = this;
// iterator2.iterable = this;
}
if (!iterator1.valid) {
iterator1.index = 0;
iterator1.valid = true;
iterator2.valid = false;
return iterator1;
}
iterator2.index = 0;
iterator2.valid = true;
iterator1.valid = false;
return iterator2;
}
}
}
131 changes: 124 additions & 7 deletions gdx/test/com/badlogic/gdx/utils/QueueTest.java
View file
@@ -1,14 +1,11 @@

package com.badlogic.gdx.utils;

import org.junit.Test;
import static org.junit.Assert.*;

import java.util.NoSuchElementException;
import java.util.Iterator;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import org.junit.Test;

public class QueueTest {

Expand Down Expand Up @@ -120,12 +117,128 @@ public void getTest () {
try {
q.get(0);
fail("get() on empty queue did not throw");
} catch (NoSuchElementException ignore) {
} catch (IndexOutOfBoundsException ignore) {
// Expected
}
}
}

@Test
public void removeTest () {
final Queue<Integer> q = new Queue<Integer>();

// Test head < tail.
for (int j = 0; j <= 6; j++)
q.addLast(j);
assertValues(q, 0, 1, 2, 3, 4, 5, 6);
q.removeIndex(0);
assertValues(q, 1, 2, 3, 4, 5, 6);
q.removeIndex(1);
assertValues(q, 1, 3, 4, 5, 6);
q.removeIndex(4);
assertValues(q, 1, 3, 4, 5);
q.removeIndex(2);
assertValues(q, 1, 3, 5);

// Test head >= tail and index >= head.
q.clear();
for (int j = 2; j >= 0; j--)
q.addFirst(j);
for (int j = 3; j <= 6; j++)
q.addLast(j);
assertValues(q, 0, 1, 2, 3, 4, 5, 6);
q.removeIndex(1);
assertValues(q, 0, 2, 3, 4, 5, 6);
q.removeIndex(0);
assertValues(q, 2, 3, 4, 5, 6);

// Test head >= tail and index < tail.
q.clear();
for (int j = 2; j >= 0; j--)
q.addFirst(j);
for (int j = 3; j <= 6; j++)
q.addLast(j);
assertValues(q, 0, 1, 2, 3, 4, 5, 6);
q.removeIndex(5);
assertValues(q, 0, 1, 2, 3, 4, 6);
q.removeIndex(5);
assertValues(q, 0, 1, 2, 3, 4);
}

@Test
public void indexOfTest () {
final Queue<Integer> q = new Queue<Integer>();

// Test head < tail.
for (int j = 0; j <= 6; j++)
q.addLast(j);
for (int j = 0; j <= 6; j++)
assertEquals(q.indexOf(j, false), j);

// Test head >= tail.
q.clear();
for (int j = 2; j >= 0; j--)
q.addFirst(j);
for (int j = 3; j <= 6; j++)
q.addLast(j);
for (int j = 0; j <= 6; j++)
assertEquals(q.indexOf(j, false), j);
}

@Test
public void iteratorTest () {
final Queue<Integer> q = new Queue<Integer>();

// Test head < tail.
for (int j = 0; j <= 6; j++)
q.addLast(j);
Iterator<Integer> iter = q.iterator();
for (int j = 0; j <= 6; j++)
assertEquals(iter.next().intValue(), j);
iter = q.iterator();
iter.next();
iter.remove();
assertValues(q, 1, 2, 3, 4, 5, 6);
iter.next();
iter.remove();
assertValues(q, 2, 3, 4, 5, 6);
iter.next();
iter.next();
iter.remove();
assertValues(q, 2, 4, 5, 6);
iter.next();
iter.next();
iter.next();
iter.remove();
assertValues(q, 2, 4, 5);

// Test head >= tail.
q.clear();
for (int j = 2; j >= 0; j--)
q.addFirst(j);
for (int j = 3; j <= 6; j++)
q.addLast(j);
iter = q.iterator();
for (int j = 0; j <= 6; j++)
assertEquals(iter.next().intValue(), j);
iter = q.iterator();
iter.next();
iter.remove();
assertValues(q, 1, 2, 3, 4, 5, 6);
iter.next();
iter.remove();
assertValues(q, 2, 3, 4, 5, 6);
iter.next();
iter.next();
iter.remove();
assertValues(q, 2, 4, 5, 6);
iter.next();
iter.next();
iter.next();
iter.remove();
assertValues(q, 2, 4, 5);
}

@Test
public void toStringTest () {
Queue<Integer> q = new Queue<Integer>(1);
Expand Down Expand Up @@ -175,4 +288,8 @@ private void assertEqualsAndHash (Queue<?> q1, Queue<?> q2) {
assertEquals("Hash codes are not equal", q1.hashCode(), q2.hashCode());
}

private void assertValues (Queue<Integer> q, Integer... values) {
for (int i = 0, n = values.length; i < n; i++)
if (values[i] != q.get(i)) fail(q + " != " + new Array(values));
}
}

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