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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) 2018, 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
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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package org.javimmutable.collections.list;
import org.javimmutable.collections.Indexed;
import org.javimmutable.collections.indexed.IndexedArray;
import org.javimmutable.collections.iterators.IndexedIterator;
import javax.annotation.Nonnull;
import java.util.Iterator;
class TreeBuilder
{
private final LeafBuilder leafBuilder;
TreeBuilder(boolean forwardOrder)
{
leafBuilder = new LeafBuilder<>(forwardOrder);
}
synchronized void add(T value)
{
leafBuilder.add(value);
}
synchronized int size()
{
return leafBuilder.size;
}
@Nonnull
synchronized Node build()
{
return leafBuilder.build();
}
@Nonnull
static Node createFromIterator(int maxSize,
boolean forwardOrder,
@Nonnull Iterator values)
{
final LeafBuilder builder = new LeafBuilder<>(forwardOrder);
while (values.hasNext() && (builder.size < maxSize)) {
builder.add(values.next());
}
return builder.build();
}
/**
* Takes a single LeafNode and returns a new Node of size maxSize containing all of the values
* from the LeafNode plus values from Iterator. If Iterator contains insufficient values to
* reach maxSize than a smaller than requested Node containing all of the values in the Iterator
* is returned.
*/
@Nonnull
static Node expandLeafNode(int maxSize,
boolean forwardOrder,
@Nonnull LeafNode nodeToFill,
@Nonnull Iterator values)
{
assert maxSize >= nodeToFill.size();
final LeafBuilder builder = new LeafBuilder<>(forwardOrder);
final Indexed nodeValues = nodeToFill.values();
final Iterable prefill = forwardOrder ? IndexedIterator.fwd(nodeValues) : IndexedIterator.rev(nodeValues);
for (T t : prefill) {
builder.add(t);
}
while (values.hasNext() && (builder.size < maxSize)) {
builder.add(values.next());
}
return builder.build();
}
/**
* Takes a single BranchNode which has an empty prefix/suffix and builds a new BranchNode
* containing all of the filled nodes from nodeToFill as a starting point plus sufficient
* values added to from the Iterator to bring the total size of the new node to maxSize.
* If the Iterator contains insufficient values to produce a node of maxSize then a smaller
* than requested node containing all values in the Iterator is returned.
*/
@Nonnull
static BranchNode expandBranchNode(int maxSize,
boolean forwardOrder,
@Nonnull BranchNode nodeToFill,
@Nonnull Iterator values)
{
assert (forwardOrder ? nodeToFill.suffix() : nodeToFill.prefix()).isEmpty();
final LeafBuilder builder = new LeafBuilder<>(forwardOrder, nodeToFill.filledNodes());
assert maxSize >= builder.size;
while (values.hasNext() && (builder.size < maxSize)) {
builder.add(values.next());
}
return (BranchNode)builder.build();
}
private static class LeafBuilder
{
private final boolean forwardOrder;
private final T[] values;
private BranchBuilder next;
private int offset;
private int remaining;
private int size;
private LeafBuilder(boolean forwardOrder)
{
this.forwardOrder = forwardOrder;
values = ListHelper.allocateValues(32);
offset = forwardOrder ? 0 : 32;
remaining = 32;
}
private LeafBuilder(boolean forwardOrder,
@Nonnull Indexed> startNodes)
{
this(forwardOrder);
next = new BranchBuilder<>(1, forwardOrder, startNodes);
for (Node node : IndexedIterator.fwd(startNodes)) {
size += node.size();
}
}
private void add(T value)
{
assert remaining >= 1;
if (forwardOrder) {
values[offset++] = value;
} else {
values[--offset] = value;
}
if (remaining == 1) {
if (next == null) {
next = new BranchBuilder<>(1, forwardOrder);
}
next.add(createNodeForNext());
offset = forwardOrder ? 0 : 32;
remaining = 32;
} else {
remaining -= 1;
}
size += 1;
}
@Nonnull
private Node createNodeForNext()
{
if (forwardOrder) {
return LeafNode.fromList(IndexedArray.retained(values), 0, offset);
} else {
return LeafNode.fromList(IndexedArray.retained(values), offset, 32);
}
}
@Nonnull
private Node build()
{
final Node myNode = (remaining == 32) ? EmptyNode.of() : createNodeForNext();
return (next == null) ? myNode : next.build(myNode);
}
}
private static class BranchBuilder
{
private final int depth;
private final boolean forwardOrder;
private final Node[] nodes;
private BranchBuilder next;
private int offset;
private int remaining;
private int size;
private BranchBuilder(int depth,
boolean forwardOrder)
{
this.depth = depth;
this.forwardOrder = forwardOrder;
nodes = ListHelper.allocateNodes(32);
next = null;
offset = forwardOrder ? 0 : 32;
remaining = 32;
size = 0;
}
private BranchBuilder(int depth,
boolean forwardOrder,
@Nonnull Indexed> startNodes)
{
this(depth, forwardOrder);
assert startNodes.size() > 0;
if (startNodes.get(0).getDepth() == depth) {
final int nodeCount = startNodes.size();
if (forwardOrder) {
for (int i = 0; i < nodeCount; ++i) {
final Node node = startNodes.get(i);
size += node.size();
nodes[offset++] = node;
}
} else {
for (int i = nodeCount - 1; i >= 0; --i) {
final Node node = startNodes.get(i);
size += node.size();
nodes[--offset] = node;
}
}
remaining -= startNodes.size();
} else {
next = new BranchBuilder<>(depth + 1, forwardOrder, startNodes);
}
}
private void add(@Nonnull Node node)
{
assert node.isFull();
assert node.getDepth() == depth;
if (forwardOrder) {
nodes[offset++] = node;
} else {
nodes[--offset] = node;
}
size += node.size();
if (remaining == 1) {
if (next == null) {
next = new BranchBuilder<>(depth + 1, forwardOrder);
}
next.add(createNodeForNext(EmptyNode.of()));
offset = forwardOrder ? 0 : 32;
remaining = 32;
size = 0;
} else {
remaining -= 1;
}
}
private Node build(@Nonnull Node extra)
{
Node node;
if (remaining == 32) {
node = extra;
} else if (remaining == 31 && next == null && extra.isEmpty()) {
final int nodeOffset = forwardOrder ? offset - 1 : offset;
return nodes[nodeOffset];
} else {
node = createNodeForNext(extra);
}
if (next != null) {
node = next.build(node);
}
return node;
}
@Nonnull
private Node createNodeForNext(@Nonnull Node extra)
{
final int nodeSize = size + extra.size();
assert nodeSize <= ListHelper.sizeForDepth(depth + 1);
if (forwardOrder) {
return BranchNode.forNodeBuilder(depth + 1, nodeSize, EmptyNode.of(), IndexedArray.retained(nodes), 0, offset, extra);
} else {
return BranchNode.forNodeBuilder(depth + 1, nodeSize, extra, IndexedArray.retained(nodes), offset, 32, EmptyNode.of());
}
}
}
}