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Library providing immutable/persistent collection classes for
Java. While collections are immutable they provide methods for
adding and removing values by creating new modified copies of
themselves. Each copy shares almost all of its structure with
other copies to minimize memory consumption.
///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2019, Burton Computer Corporation
// 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 Burton Computer Corporation 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
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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package org.javimmutable.collections.list;
import org.javimmutable.collections.Func2;
import org.javimmutable.collections.Proc1Throws;
import org.javimmutable.collections.Sum1Throws;
import org.javimmutable.collections.common.ArrayHelper;
import org.javimmutable.collections.indexed.IndexedArray;
import org.javimmutable.collections.iterators.GenericIterator;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import java.util.Arrays;
import java.util.StringJoiner;
import java.util.function.Consumer;
@Immutable
class MultiValueNode
extends AbstractNode
implements ArrayHelper.Allocator
{
static final int MAX_SIZE = 128;
static final int SPLIT_SIZE = MAX_SIZE / 2;
private final T[] values;
MultiValueNode(T a,
T b)
{
values = allocate(2);
values[0] = a;
values[1] = b;
}
/**
* Builds a leaf node using the provided array directly (i.e. not copied).
*
* @param values array to retain and use for leaf node
*/
private MultiValueNode(T[] values)
{
assert values.length > 1;
assert values.length <= MAX_SIZE;
this.values = values;
}
/**
* Builds a leaf node using a new array of specified size copied from the provided array.
*
* @param values array to copy for use in leaf node
*/
MultiValueNode(T[] values,
int count)
{
assert count > 1;
assert count <= MAX_SIZE;
this.values = allocate(count);
System.arraycopy(values, 0, this.values, 0, count);
}
/**
* Builds a leaf node using a new array populated by calling copyTo() on the two nodes.
* Total size of the two nodes must not exceed MAX_SIZE.
*/
MultiValueNode(@Nonnull AbstractNode left,
@Nonnull AbstractNode right,
int size)
{
assert size > 1;
assert size <= MAX_SIZE;
assert size == (left.size() + right.size());
values = allocate(size);
left.copyTo(values, 0);
right.copyTo(values, left.size());
}
@Override
boolean isEmpty()
{
return values.length == 0;
}
@Override
int size()
{
return values.length;
}
@Override
int depth()
{
return 0;
}
@Override
T get(int index)
{
return values[index];
}
@Nonnull
@Override
AbstractNode append(T value)
{
return insert(values.length, value);
}
@Nonnull
@Override
AbstractNode append(@Nonnull AbstractNode node)
{
if (node.isEmpty()) {
return this;
} else if (node.depth() > 0) {
return node.prepend(this);
} else {
final int combinedSize = size() + node.size();
if (combinedSize <= MAX_SIZE) {
return new MultiValueNode<>(this, node, combinedSize);
} else {
return new BranchNode<>(this, node, combinedSize);
}
}
}
@Nonnull
@Override
AbstractNode prepend(T value)
{
return insert(0, value);
}
@Nonnull
@Override
AbstractNode prepend(@Nonnull AbstractNode node)
{
if (node.isEmpty()) {
return this;
} else if (node.depth() > 0) {
return node.append(this);
} else {
final int combinedSize = size() + node.size();
if (combinedSize <= MAX_SIZE) {
return new MultiValueNode<>(node, this, combinedSize);
} else {
return new BranchNode<>(node, this, combinedSize);
}
}
}
@Nonnull
@Override
AbstractNode assign(int index,
T value)
{
return new MultiValueNode<>(ArrayHelper.assign(values, index, value));
}
@Nonnull
@Override
AbstractNode insert(int index,
T value)
{
if (values.length < MAX_SIZE) {
return new MultiValueNode<>(ArrayHelper.insert(this, values, index, value));
} else {
final T[] left, right;
if (index <= SPLIT_SIZE) {
left = ArrayHelper.prefixInsert(this, values, SPLIT_SIZE, index, value);
right = ArrayHelper.suffix(this, values, SPLIT_SIZE);
} else {
left = ArrayHelper.prefix(this, values, SPLIT_SIZE);
right = ArrayHelper.suffixInsert(this, values, SPLIT_SIZE, index, value);
}
return new BranchNode<>(new MultiValueNode<>(left), new MultiValueNode<>(right));
}
}
@Nonnull
@Override
AbstractNode delete(int index)
{
final int length = values.length;
if (index < 0 || index >= length) {
throw new IndexOutOfBoundsException();
} else if (length == 1) {
ArrayHelper.checkBounds(values, index);
return EmptyNode.instance();
} else if (length == 2) {
return new OneValueNode<>(values[1 - index]);
} else {
return new MultiValueNode<>(ArrayHelper.delete(this, values, index));
}
}
@Nonnull
@Override
AbstractNode deleteFirst()
{
return delete(0);
}
@Nonnull
@Override
AbstractNode deleteLast()
{
return delete(values.length - 1);
}
@Override
void copyTo(T[] array,
int offset)
{
System.arraycopy(values, 0, array, offset, values.length);
}
@Nonnull
@Override
AbstractNode prefix(int limit)
{
final int length = values.length;
if (limit < 0 || limit > length) {
throw new IndexOutOfBoundsException();
} else if (limit == 0) {
return EmptyNode.instance();
} else if (limit == length) {
return this;
} else if (limit == 1) {
return new OneValueNode<>(values[0]);
} else {
return new MultiValueNode<>(ArrayHelper.prefix(this, values, limit));
}
}
@Nonnull
@Override
AbstractNode suffix(int offset)
{
final int length = values.length;
if (offset < 0 || offset > length) {
throw new IndexOutOfBoundsException();
} else if (offset == 0) {
return this;
} else if (offset == length - 1) {
return new OneValueNode<>(values[offset]);
} else if (offset == length) {
return EmptyNode.instance();
} else {
return new MultiValueNode<>(ArrayHelper.suffix(this, values, offset));
}
}
@SuppressWarnings("unchecked")
@Nonnull
@Override
public T[] allocate(int size)
{
assert size > 0;
return (T[])new Object[size];
}
@Override
public void checkInvariants()
{
int currentSize = values.length;
if (currentSize < 1 || currentSize > MAX_SIZE) {
throw new RuntimeException(String.format("incorrect size: currentSize=%d", currentSize));
}
}
@Override
public boolean equals(Object o)
{
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
MultiValueNode leafNode = (MultiValueNode)o;
// Probably incorrect - comparing Object[] arrays with Arrays.equals
return Arrays.equals(values, leafNode.values);
}
@Override
public int hashCode()
{
return Arrays.hashCode(values);
}
@Override
public String toString()
{
return new StringJoiner(", ", MultiValueNode.class.getSimpleName() + "[", "]")
.add("values=" + Arrays.toString(values))
.toString();
}
@Nullable
@Override
public GenericIterator.State iterateOverRange(@Nullable GenericIterator.State parent,
int offset,
int limit)
{
assert offset >= 0 && offset <= limit && limit <= values.length;
return GenericIterator.multiValueState(parent, IndexedArray.retained(values), offset, limit);
}
@Override
public void forEach(Consumer action)
{
for (T value : values) {
action.accept(value);
}
}
@Override
public void forEachThrows(@Nonnull Proc1Throws proc)
throws E
{
for (T value : values) {
proc.apply(value);
}
}
@Override
public V reduce(V sum,
Func2 accumulator)
{
for (T value : values) {
sum = accumulator.apply(sum, value);
}
return sum;
}
@Override
public V reduceThrows(V sum,
Sum1Throws accumulator)
throws E
{
for (T value : values) {
sum = accumulator.apply(sum, value);
}
return sum;
}
}