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/*
* Copyright (C) 2002-2017 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.objects;
import it.unimi.dsi.fastutil.Stack;
import java.util.List;
import java.util.Iterator;
import java.util.ListIterator;
import java.util.Collection;
import java.util.NoSuchElementException;
/**
* An abstract class providing basic methods for lists implementing a
* type-specific list interface.
*
*
* As an additional bonus, this class implements on top of the list operations a
* type-specific stack.
*/
public abstract class AbstractObjectList extends AbstractObjectCollection implements ObjectList, Stack {
protected AbstractObjectList() {
}
/**
* Ensures that the given index is nonnegative and not greater than the list
* size.
*
* @param index
* an index.
* @throws IndexOutOfBoundsException
* if the given index is negative or greater than the list size.
*/
protected void ensureIndex(final int index) {
if (index < 0)
throw new IndexOutOfBoundsException("Index (" + index + ") is negative");
if (index > size())
throw new IndexOutOfBoundsException("Index (" + index + ") is greater than list size (" + (size()) + ")");
}
/**
* Ensures that the given index is nonnegative and smaller than the list size.
*
* @param index
* an index.
* @throws IndexOutOfBoundsException
* if the given index is negative or not smaller than the list size.
*/
protected void ensureRestrictedIndex(final int index) {
if (index < 0)
throw new IndexOutOfBoundsException("Index (" + index + ") is negative");
if (index >= size())
throw new IndexOutOfBoundsException(
"Index (" + index + ") is greater than or equal to list size (" + (size()) + ")");
}
/**
* {@inheritDoc}
*
*
* This implementation always throws an {@link UnsupportedOperationException}.
*/
@Override
public void add(final int index, final K k) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
*
* This implementation delegates to the type-specific version of
* {@link List#add(int, Object)}.
*/
@Override
public boolean add(final K k) {
add(size(), k);
return true;
}
/**
* {@inheritDoc}
*
*
* This implementation always throws an {@link UnsupportedOperationException}.
*/
@Override
public K remove(final int i) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
*
* This implementation always throws an {@link UnsupportedOperationException}.
*/
@Override
public K set(final int index, final K k) {
throw new UnsupportedOperationException();
}
/**
* Adds all of the elements in the specified collection to this list (optional
* operation).
*/
@Override
public boolean addAll(int index, final Collection c) {
ensureIndex(index);
final Iterator i = c.iterator();
final boolean retVal = i.hasNext();
while (i.hasNext())
add(index++, (i.next()));
return retVal;
}
/**
* {@inheritDoc}
*
*
* This implementation delegates to the type-specific version of
* {@link List#addAll(int, Collection)}.
*/
@Override
public boolean addAll(final Collection c) {
return addAll(size(), c);
}
/**
* {@inheritDoc}
*
*
* This implementation delegates to {@link #listIterator()}.
*/
@Override
public ObjectListIterator iterator() {
return listIterator();
}
/**
* {@inheritDoc}
*
*
* This implementation delegates to {@link #listIterator(int) listIterator(0)}.
*/
@Override
public ObjectListIterator listIterator() {
return listIterator(0);
}
/**
* {@inheritDoc}
*
* This implementation is based on the random-access methods.
*/
@Override
public ObjectListIterator listIterator(final int index) {
ensureIndex(index);
return new ObjectListIterator() {
int pos = index, last = -1;
@Override
public boolean hasNext() {
return pos < AbstractObjectList.this.size();
}
@Override
public boolean hasPrevious() {
return pos > 0;
}
@Override
public K next() {
if (!hasNext())
throw new NoSuchElementException();
return AbstractObjectList.this.get(last = pos++);
}
@Override
public K previous() {
if (!hasPrevious())
throw new NoSuchElementException();
return AbstractObjectList.this.get(last = --pos);
}
@Override
public int nextIndex() {
return pos;
}
@Override
public int previousIndex() {
return pos - 1;
}
@Override
public void add(final K k) {
AbstractObjectList.this.add(pos++, k);
last = -1;
}
@Override
public void set(final K k) {
if (last == -1)
throw new IllegalStateException();
AbstractObjectList.this.set(last, k);
}
@Override
public void remove() {
if (last == -1)
throw new IllegalStateException();
AbstractObjectList.this.remove(last);
/*
* If the last operation was a next(), we are removing an element *before* us,
* and we must decrease pos correspondingly.
*/
if (last < pos)
pos--;
last = -1;
}
};
}
/**
* Returns true if this list contains the specified element.
*
* This implementation delegates to {@code indexOf()}.
*
* @see List#contains(Object)
*/
@Override
public boolean contains(final Object k) {
return indexOf(k) >= 0;
}
@Override
public int indexOf(final Object k) {
final ObjectListIterator i = listIterator();
K e;
while (i.hasNext()) {
e = i.next();
if (java.util.Objects.equals(k, e))
return i.previousIndex();
}
return -1;
}
@Override
public int lastIndexOf(final Object k) {
ObjectListIterator i = listIterator(size());
K e;
while (i.hasPrevious()) {
e = i.previous();
if (java.util.Objects.equals(k, e))
return i.nextIndex();
}
return -1;
}
@Override
public void size(final int size) {
int i = size();
if (size > i)
while (i++ < size)
add((null));
else
while (i-- != size)
remove(i);
}
@Override
public ObjectList subList(final int from, final int to) {
ensureIndex(from);
ensureIndex(to);
if (from > to)
throw new IndexOutOfBoundsException("Start index (" + from + ") is greater than end index (" + to + ")");
return new ObjectSubList<>(this, from, to);
}
/**
* {@inheritDoc}
*
*
* This is a trivial iterator-based implementation. It is expected that
* implementations will override this method with a more optimized version.
*/
@Override
public void removeElements(final int from, final int to) {
ensureIndex(to);
ObjectListIterator i = listIterator(from);
int n = to - from;
if (n < 0)
throw new IllegalArgumentException("Start index (" + from + ") is greater than end index (" + to + ")");
while (n-- != 0) {
i.next();
i.remove();
}
}
/**
* {@inheritDoc}
*
*
* This is a trivial iterator-based implementation. It is expected that
* implementations will override this method with a more optimized version.
*/
@Override
public void addElements(int index, final K a[], int offset, int length) {
ensureIndex(index);
if (offset < 0)
throw new ArrayIndexOutOfBoundsException("Offset (" + offset + ") is negative");
if (offset + length > a.length)
throw new ArrayIndexOutOfBoundsException(
"End index (" + (offset + length) + ") is greater than array length (" + a.length + ")");
while (length-- != 0)
add(index++, a[offset++]);
}
/**
* {@inheritDoc}
*
*
* This implementation delegates to the analogous method for array fragments.
*/
@Override
public void addElements(final int index, final K a[]) {
addElements(index, a, 0, a.length);
}
/**
* {@inheritDoc}
*
*
* This is a trivial iterator-based implementation. It is expected that
* implementations will override this method with a more optimized version.
*/
@Override
public void getElements(final int from, final Object a[], int offset, int length) {
ObjectListIterator i = listIterator(from);
if (offset < 0)
throw new ArrayIndexOutOfBoundsException("Offset (" + offset + ") is negative");
if (offset + length > a.length)
throw new ArrayIndexOutOfBoundsException(
"End index (" + (offset + length) + ") is greater than array length (" + a.length + ")");
if (from + length > size())
throw new IndexOutOfBoundsException(
"End index (" + (from + length) + ") is greater than list size (" + size() + ")");
while (length-- != 0)
a[offset++] = i.next();
}
/**
* {@inheritDoc}
*
* This implementation delegates to {@link #removeElements(int, int)}.
*/
@Override
public void clear() {
removeElements(0, size());
}
private boolean valEquals(final Object a, final Object b) {
return a == null ? b == null : a.equals(b);
}
/**
* Returns the hash code for this list, which is identical to
* {@link java.util.List#hashCode()}.
*
* @return the hash code for this list.
*/
@Override
public int hashCode() {
ObjectIterator i = iterator();
int h = 1, s = size();
while (s-- != 0) {
K k = i.next();
h = 31 * h + ((k) == null ? 0 : (k).hashCode());
}
return h;
}
@Override
public boolean equals(final Object o) {
if (o == this)
return true;
if (!(o instanceof List))
return false;
final List l = (List) o;
int s = size();
if (s != l.size())
return false;
final ListIterator i1 = listIterator(), i2 = l.listIterator();
while (s-- != 0)
if (!valEquals(i1.next(), i2.next()))
return false;
return true;
}
/**
* Compares this list to another object. If the argument is a
* {@link java.util.List}, this method performs a lexicographical comparison;
* otherwise, it throws a {@code ClassCastException}.
*
* @param l
* a list.
* @return if the argument is a {@link java.util.List}, a negative integer,
* zero, or a positive integer as this list is lexicographically less
* than, equal to, or greater than the argument.
* @throws ClassCastException
* if the argument is not a list.
*/
@SuppressWarnings("unchecked")
@Override
public int compareTo(final List l) {
if (l == this)
return 0;
if (l instanceof ObjectList) {
final ObjectListIterator i1 = listIterator(), i2 = ((ObjectList) l).listIterator();
int r;
K e1, e2;
while (i1.hasNext() && i2.hasNext()) {
e1 = i1.next();
e2 = i2.next();
if ((r = (((Comparable) (e1)).compareTo(e2))) != 0)
return r;
}
return i2.hasNext() ? -1 : (i1.hasNext() ? 1 : 0);
}
ListIterator i1 = listIterator(), i2 = l.listIterator();
int r;
while (i1.hasNext() && i2.hasNext()) {
if ((r = ((Comparable) i1.next()).compareTo(i2.next())) != 0)
return r;
}
return i2.hasNext() ? -1 : (i1.hasNext() ? 1 : 0);
}
@Override
public void push(final K o) {
add(o);
}
@Override
public K pop() {
if (isEmpty())
throw new NoSuchElementException();
return remove(size() - 1);
}
@Override
public K top() {
if (isEmpty())
throw new NoSuchElementException();
return get(size() - 1);
}
@Override
public K peek(final int i) {
return get(size() - 1 - i);
}
@Override
public String toString() {
final StringBuilder s = new StringBuilder();
final ObjectIterator i = iterator();
int n = size();
K k;
boolean first = true;
s.append("[");
while (n-- != 0) {
if (first)
first = false;
else
s.append(", ");
k = i.next();
if (this == k)
s.append("(this list)");
else
s.append(String.valueOf(k));
}
s.append("]");
return s.toString();
}
/** A class implementing a sublist view. */
public static class ObjectSubList extends AbstractObjectList implements java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
/** The list this sublist restricts. */
protected final ObjectList l;
/** Initial (inclusive) index of this sublist. */
protected final int from;
/** Final (exclusive) index of this sublist. */
protected int to;
public ObjectSubList(final ObjectList l, final int from, final int to) {
this.l = l;
this.from = from;
this.to = to;
}
private boolean assertRange() {
assert from <= l.size();
assert to <= l.size();
assert to >= from;
return true;
}
@Override
public boolean add(final K k) {
l.add(to, k);
to++;
assert assertRange();
return true;
}
@Override
public void add(final int index, final K k) {
ensureIndex(index);
l.add(from + index, k);
to++;
assert assertRange();
}
@Override
public boolean addAll(final int index, final Collection c) {
ensureIndex(index);
to += c.size();
return l.addAll(from + index, c);
}
@Override
public K get(final int index) {
ensureRestrictedIndex(index);
return l.get(from + index);
}
@Override
public K remove(final int index) {
ensureRestrictedIndex(index);
to--;
return l.remove(from + index);
}
@Override
public K set(final int index, final K k) {
ensureRestrictedIndex(index);
return l.set(from + index, k);
}
@Override
public int size() {
return to - from;
}
@Override
public void getElements(final int from, final Object[] a, final int offset, final int length) {
ensureIndex(from);
if (from + length > size())
throw new IndexOutOfBoundsException(
"End index (" + from + length + ") is greater than list size (" + size() + ")");
l.getElements(this.from + from, a, offset, length);
}
@Override
public void removeElements(final int from, final int to) {
ensureIndex(from);
ensureIndex(to);
l.removeElements(this.from + from, this.from + to);
this.to -= (to - from);
assert assertRange();
}
@Override
public void addElements(int index, final K a[], int offset, int length) {
ensureIndex(index);
l.addElements(this.from + index, a, offset, length);
this.to += length;
assert assertRange();
}
@Override
public ObjectListIterator listIterator(final int index) {
ensureIndex(index);
return new ObjectListIterator() {
int pos = index, last = -1;
@Override
public boolean hasNext() {
return pos < size();
}
@Override
public boolean hasPrevious() {
return pos > 0;
}
@Override
public K next() {
if (!hasNext())
throw new NoSuchElementException();
return l.get(from + (last = pos++));
}
@Override
public K previous() {
if (!hasPrevious())
throw new NoSuchElementException();
return l.get(from + (last = --pos));
}
@Override
public int nextIndex() {
return pos;
}
@Override
public int previousIndex() {
return pos - 1;
}
@Override
public void add(K k) {
if (last == -1)
throw new IllegalStateException();
ObjectSubList.this.add(pos++, k);
last = -1;
assert assertRange();
}
@Override
public void set(K k) {
if (last == -1)
throw new IllegalStateException();
ObjectSubList.this.set(last, k);
}
@Override
public void remove() {
if (last == -1)
throw new IllegalStateException();
ObjectSubList.this.remove(last);
/*
* If the last operation was a next(), we are removing an element *before* us,
* and we must decrease pos correspondingly.
*/
if (last < pos)
pos--;
last = -1;
assert assertRange();
}
};
}
@Override
public ObjectList subList(final int from, final int to) {
ensureIndex(from);
ensureIndex(to);
if (from > to)
throw new IllegalArgumentException("Start index (" + from + ") is greater than end index (" + to + ")");
return new ObjectSubList<>(this, from, to);
}
}
}