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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) 2017, 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
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package org.javimmutable.collections.array.trie32;
import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.Indexed;
import org.javimmutable.collections.JImmutableArray;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.MutableBuilder;
import org.javimmutable.collections.common.AbstractJImmutableArray;
import org.javimmutable.collections.common.MutableDelta;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
@Immutable
public class TrieArray
extends AbstractJImmutableArray
{
@SuppressWarnings("unchecked")
private static final TrieArray EMPTY = new TrieArray(TrieNode.of(), 0);
private final TrieNode root;
private final int size;
private TrieArray(TrieNode root,
int size)
{
this.root = root;
this.size = size;
}
public static Builder builder()
{
return new Builder();
}
@SuppressWarnings("unchecked")
public static TrieArray of()
{
return (TrieArray)EMPTY;
}
/**
* Efficiently constructs a TrieArray containing the objects from source (in the specified range).
* In the constructed TrieArray objects will have array indexes starting at 0 (i.e. indexes
* from the source are not carried over) so if offset is 10 then source.get(10) will map to
* array.get(0).
*
* @param source
* @param offset
* @param limit
* @param
* @return
* @deprecated use builder() instead
*/
@Deprecated
public static JImmutableArray of(Indexed source,
int offset,
int limit)
{
return TrieArray.builder().add(source, offset, limit).build();
}
// made obsolete by Builder but retained for use in unit test
static JImmutableArray oldof(Indexed source,
int offset,
int limit)
{
final int size = limit - offset;
if (size == 0) {
return of();
}
// small lists can be directly constructed from a single leaf array
if (size <= 32) {
return new TrieArray(TrieNode.fromSource(0, source, offset, limit), size);
}
// first construct an array containing a single level of arrays of leaves
final int numBranches = Math.min(32, ((limit - offset) + 31) / 32);
@SuppressWarnings("unchecked") final TrieNode[] branchArray = (TrieNode[])new TrieNode[numBranches];
int index = 0;
for (int b = 0; b < numBranches; ++b) {
int branchSize = Math.min(32, limit - offset);
branchArray[b] = TrieNode.fromSource(index, source, offset, limit);
offset += branchSize;
index += branchSize;
}
// then add any extras left over above that size
JImmutableArray array = new TrieArray(MultiBranchTrieNode.forEntries(5, branchArray), index);
while (offset < limit) {
array = array.assign(index++, source.get(offset++));
}
return array;
}
@Override
@Nullable
public T getValueOr(int index,
@Nullable T defaultValue)
{
if (root.getShift() < TrieNode.shiftForIndex(index)) {
return defaultValue;
} else {
return root.getValueOr(root.getShift(), index, defaultValue);
}
}
@Nonnull
@Override
public Holder find(int index)
{
if (root.getShift() < TrieNode.shiftForIndex(index)) {
return Holders.of();
} else {
return root.find(root.getShift(), index);
}
}
@Nonnull
@Override
public JImmutableArray assign(int index,
@Nullable T value)
{
MutableDelta sizeDelta = new MutableDelta();
TrieNode newRoot = root.paddedToMinimumDepthForShift(TrieNode.shiftForIndex(index));
newRoot = newRoot.assign(newRoot.getShift(), index, value, sizeDelta);
return (newRoot == root) ? this : new TrieArray(newRoot, size + sizeDelta.getValue());
}
@Nonnull
@Override
public JImmutableArray delete(int index)
{
if (root.getShift() < TrieNode.shiftForIndex(index)) {
return this;
} else {
MutableDelta sizeDelta = new MutableDelta();
final TrieNode newRoot = root.delete(root.getShift(), index, sizeDelta).trimmedToMinimumDepth();
return (newRoot == root) ? this : new TrieArray(newRoot, size + sizeDelta.getValue());
}
}
@Override
public int size()
{
return size;
}
@Nonnull
@Override
public JImmutableArray deleteAll()
{
return of();
}
@Override
@Nonnull
public Cursor> cursor()
{
return root.signedOrderEntryCursor();
}
@Override
public void checkInvariants()
{
//TODO: fix empty checkInvariants()
}
public static class Builder
implements MutableBuilder>
{
private final List> leaves = new ArrayList>();
@Nonnull
@Override
public Builder add(T value)
{
final TrieNode leaf = LeafTrieNode.of(leaves.size(), value);
leaves.add(leaf);
return this;
}
@Nonnull
@Override
public TrieArray build()
{
int nodeCount = leaves.size();
if (nodeCount == 0) {
return of();
}
if (nodeCount == 1) {
return new TrieArray(leaves.get(0), 1);
}
List> dst = new ArrayList>();
List> src = leaves;
int shift = 0;
while (nodeCount > 1) {
int dstOffset = 0;
int srcOffset = 0;
while (srcOffset < nodeCount) {
final int count = Math.min(32, nodeCount - srcOffset);
TrieNode[] nodes = allocate(count);
for (int i = 0; i < count; ++i) {
nodes[i] = src.get(srcOffset++);
}
TrieNode branch;
switch (count) {
case 1:
branch = SingleBranchTrieNode.forBranchIndex(shift, 0, nodes[0]);
break;
case 32:
branch = new FullBranchTrieNode(shift, nodes);
break;
default:
branch = MultiBranchTrieNode.forEntries(shift, nodes);
break;
}
set(dst, dstOffset++, branch);
}
shift += 5;
src = dst;
nodeCount = dstOffset;
}
assert nodeCount == 1;
return new TrieArray(dst.get(0), leaves.size());
}
@Nonnull
@Override
public Builder add(Cursor source)
{
for (Cursor cursor = source.start(); cursor.hasValue(); cursor = cursor.next()) {
add(cursor.getValue());
}
return this;
}
@Nonnull
@Override
public Builder add(Iterator source)
{
while (source.hasNext()) {
add(source.next());
}
return this;
}
@Nonnull
@Override
public Builder add(Collection source)
{
add(source.iterator());
return this;
}
@Nonnull
@Override
public Builder add(K... source)
{
for (T value : source) {
add(value);
}
return this;
}
@Nonnull
@Override
public Builder add(Indexed source)
{
return add(source, 0, source.size());
}
@Nonnull
@Override
public Builder add(Indexed source,
int offset,
int limit)
{
for (int i = offset; i < limit; ++i) {
add(source.get(i));
}
return this;
}
private void set(List> dst,
int index,
TrieNode node)
{
if (index < dst.size()) {
dst.set(index, node);
} else {
assert index == dst.size();
dst.add(node);
}
}
@SuppressWarnings("unchecked")
private TrieNode[] allocate(int size)
{
return new TrieNode[size];
}
}
}