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/*
* Copyright (C) 2010-2023 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 java.util.List;
import java.util.Spliterator;
import static it.unimi.dsi.fastutil.BigArrays.length;
import it.unimi.dsi.fastutil.BigArrays;
import it.unimi.dsi.fastutil.BigList;
/**
* A type-specific {@link BigList}; provides some additional methods that use polymorphism to avoid
* (un)boxing.
*
*
* Additionally, this interface strengthens {@link #iterator()}, {@link #listIterator()},
* {@link #listIterator(long)} and {@link #subList(long,long)}.
*
*
* This interface specifies reference equality semantics (members will be compared equal with
* {@code ==} instead of {@link Object#equals(Object) equals}), which may result in breaks in
* contract if attempted to be used with non reference-equality semantics based {@link BigList}s.
* For example, a {@code aReferenceBigList.equals(aObjectBigList)} may return different a different
* result then {@code aObjectBigList.equals(aReferenceBigList)}, in violation of
* {@link Object#equals equals}'s contract requiring it being symmetric.
*
*
* Besides polymorphic methods, this interfaces specifies methods to copy into an array or remove
* contiguous sublists. Although the abstract implementation of this interface provides simple,
* one-by-one implementations of these methods, it is expected that concrete implementation override
* them with optimized versions.
*
* @see List
*/
public interface ReferenceBigList extends BigList, ReferenceCollection {
/**
* Returns a type-specific iterator on the elements of this list.
*
* @apiNote This specification strengthens the one given in {@link java.util.Collection#iterator()}.
* @see java.util.Collection#iterator()
*/
@Override
ObjectBigListIterator iterator();
/**
* Returns a type-specific big-list iterator on this type-specific big list.
*
* @apiNote This specification strengthens the one given in {@link BigList#listIterator()}.
* @see BigList#listIterator()
*/
@Override
ObjectBigListIterator listIterator();
/**
* Returns a type-specific list iterator on this type-specific big list starting at a given index.
*
* @apiNote This specification strengthens the one given in {@link BigList#listIterator(long)}.
* @see BigList#listIterator(long)
*/
@Override
ObjectBigListIterator listIterator(long index);
/**
* Returns a type-specific spliterator on the elements of this big-list.
*
*
* BigList spliterators must report at least {@link Spliterator#SIZED} and
* {@link Spliterator#ORDERED}.
*
*
* See {@link java.util.List#spliterator()} for more documentation on the requirements of the
* returned spliterator (despite {@code BigList} not being a {@code List}, most of the same
* requirements apply.
*
* @apiNote This is generally the only {@code spliterator} method subclasses should override.
*
* @implSpec The default implementation returns a late-binding spliterator (see {@link Spliterator}
* for documentation on what binding policies mean).
*
* - For {@link java.util.RandomAccess RandomAccess} lists, this will return a
* spliterator that calls the type-specific {@link #get(long)} method on the appropriate
* indexes.
* - Otherwise, the spliterator returned will wrap this instance's type specific
* {@link #iterator}.
*
*
* In either case, the spliterator reports {@link Spliterator#SIZED},
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
*
* @implNote As the non-{@linkplain java.util.RandomAccess RandomAccess} case is based on the
* iterator, and {@link java.util.Iterator} is an inherently linear API, the returned
* spliterator will yield limited performance gains when run in parallel contexts, as the
* returned spliterator's {@link Spliterator#trySplit() trySplit()} will have linear
* runtime.
*
* For {@link java.util.RandomAccess RandomAccess} lists, the parallel performance should
* be reasonable assuming {@link #get(long)} is truly constant time like
* {@link java.util.RandomAccess RandomAccess} suggests.
*
* @return {@inheritDoc}
* @since 8.5.0
*/
@Override
default ObjectSpliterator spliterator() {
return ObjectSpliterators.asSpliterator(iterator(), size64(), ObjectSpliterators.LIST_SPLITERATOR_CHARACTERISTICS);
}
/**
* Returns a type-specific view of the portion of this type-specific big list from the index
* {@code from}, inclusive, to the index {@code to}, exclusive.
*
* @apiNote This specification strengthens the one given in {@link BigList#subList(long,long)}.
*
* @see BigList#subList(long,long)
*/
@Override
ReferenceBigList subList(long from, long to);
/**
* Copies (hopefully quickly) elements of this type-specific big list into the given big array.
*
* @param from the start index (inclusive).
* @param a the destination big array.
* @param offset the offset into the destination big array where to store the first element copied.
* @param length the number of elements to be copied.
*/
void getElements(long from, Object a[][], long offset, long length);
/**
* Copies (hopefully quickly) elements of this type-specific big list into the given array.
*
* @param from the start index (inclusive).
* @param a the destination array.
* @param offset the offset into the destination array where to store the first element copied.
* @param length the number of elements to be copied.
*/
default void getElements(long from, Object a[], int offset, int length) {
getElements(from, new Object[][] { a }, (long)offset, (long)length);
}
/**
* Removes (hopefully quickly) elements of this type-specific big list.
*
* @param from the start index (inclusive).
* @param to the end index (exclusive).
*/
void removeElements(long from, long to);
/**
* Add (hopefully quickly) elements to this type-specific big list.
*
* @param index the index at which to add elements.
* @param a the big array containing the elements.
*/
void addElements(long index, K a[][]);
/**
* Add (hopefully quickly) elements to this type-specific big list.
*
* @param index the index at which to add elements.
* @param a the big array containing the elements.
* @param offset the offset of the first element to add.
* @param length the number of elements to add.
*/
void addElements(long index, K a[][], long offset, long length);
/**
* Set (hopefully quickly) elements to match the array given.
*
* @param a the big array containing the elements.
* @since 8.5.0
*/
default void setElements(K a[][]) {
setElements(0, a);
}
/**
* Set (hopefully quickly) elements to match the array given.
*
* @param index the index at which to start setting elements.
* @param a the big array containing the elements.
* @since 8.5.0
*/
default void setElements(long index, K a[][]) {
setElements(index, a, 0, length(a));
}
/**
* Set (hopefully quickly) elements to match the array given.
*
* Sets each in this list to the corresponding elements in the array, as if by
*
*
* ListIterator iter = listIterator(index);
* long i = 0;
* while (i < length) {
* iter.next();
* iter.set(BigArrays.get(a, offset + i++);
* }
*
*
* However, the exact implementation may be more efficient, taking into account whether random
* access is faster or not, or at the discretion of subclasses, abuse internals.
*
* @param index the index at which to start setting elements.
* @param a the big array containing the elements.
* @param offset the offset of the first element to add.
* @param length the number of elements to add.
* @since 8.5.0
*/
default void setElements(long index, K a[][], long offset, long length) {
// We can't use AbstractList#ensureIndex, sadly.
if (index < 0) throw new IndexOutOfBoundsException("Index (" + index + ") is negative");
if (index > size64()) throw new IndexOutOfBoundsException("Index (" + index + ") is greater than list size (" + (size64()) + ")");
BigArrays.ensureOffsetLength(a, offset, length);
if (index + length > size64()) throw new IndexOutOfBoundsException("End index (" + (index + length) + ") is greater than list size (" + size64() + ")");
ObjectBigListIterator iter = listIterator(index);
long i = 0;
while (i < length) {
iter.next();
iter.set(BigArrays.get(a, offset + i++));
}
}
/**
* Inserts all of the elements in the specified type-specific big list into this type-specific big
* list at the specified position (optional operation).
*
* @apiNote This method exists only for the sake of efficiency: override are expected to use
* {@link #getElements}/{@link #addElements}.
* @implSpec This method delegates to the one accepting a collection, but it might be implemented
* more efficiently.
* @see BigList#addAll(long,Collection)
*/
default boolean addAll(final long index, final ReferenceBigList l) {
return addAll(index, (ReferenceCollection)l);
}
/**
* Appends all of the elements in the specified type-specific big list to the end of this
* type-specific big list (optional operation).
*
* @implSpec This method delegates to the index-based version, passing {@link #size()} as first
* argument.
* @see BigList#addAll(Collection)
*/
default boolean addAll(final ReferenceBigList l) {
return addAll(size64(), l);
}
/**
* Inserts all of the elements in the specified type-specific list into this type-specific big list
* at the specified position (optional operation).
*
* @apiNote This method exists only for the sake of efficiency: override are expected to use
* {@link #getElements}/{@link #addElements}.
* @implSpec This method delegates to the one accepting a collection, but it might be implemented
* more efficiently.
* @see BigList#addAll(long,Collection)
*/
default boolean addAll(final long index, final ReferenceList l) {
return addAll(index, (ReferenceCollection)l);
}
/**
* Appends all of the elements in the specified type-specific list to the end of this type-specific
* big list (optional operation).
*
* @implSpec This method delegates to the index-based version, passing {@link #size()} as first
* argument.
* @see BigList#addAll(Collection)
*/
default boolean addAll(final ReferenceList l) {
return addAll(size64(), l);
}
// Without any toBigArray methods, there is no sensible default sort methods we can have.
}