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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) 2013, Burton Computer Corporation
// All rights reserved.
//
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//
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// the documentation and/or other materials provided with the
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// of its contributors may be used to endorse or promote products
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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package org.javimmutable.collections.array.trie;
import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Func1;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.Indexed;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.array.bit32.Bit32Array;
import org.javimmutable.collections.common.IndexedArray;
import org.javimmutable.collections.cursors.LazyCursor;
import org.javimmutable.collections.cursors.MultiCursor;
import org.javimmutable.collections.cursors.MultiTransformCursor;
import org.javimmutable.collections.cursors.TransformCursor;
public final class StandardTrieNode
extends AbstractTrieNode
{
private final Bit32Array> branches;
private final Bit32Array values;
public StandardTrieNode(int branchIndex,
int valueIndex,
T value)
{
if (branchIndex == 0) {
this.branches = Bit32Array.of();
this.values = Bit32Array.of().assign(valueIndex, value);
} else {
this.branches = Bit32Array.>of().assign(branchIndex & 0x1f, new QuickTrieNode(branchIndex >>> 5, valueIndex, value));
this.values = Bit32Array.of();
}
}
public StandardTrieNode(Bit32Array> branches,
Bit32Array values)
{
this.branches = branches;
this.values = values;
}
/**
* Fast constructor creating a StandardTrieNode holding (limit - offset) consecutive values
* from the specified Indexed collection. (limit - offset) must be in the range 0 to 32*32
* (1024) inclusive.
*
* @param source
* @param offset
* @param limit
*/
@SuppressWarnings("unchecked")
public StandardTrieNode(Indexed source,
int offset,
int limit)
{
final int size = limit - offset;
if (size < 0 || size > 32 * 32) {
throw new IllegalArgumentException("invalid size: " + size);
}
if (size <= 32) {
this.values = Bit32Array.of(source, 0, offset, limit);
this.branches = Bit32Array.of();
} else {
this.values = Bit32Array.of(source, 0, offset, offset + 32);
final int numBranches = ((limit - offset + 31) / 32) - 1;
final TrieNode[] branchArray = (TrieNode[])new TrieNode[numBranches];
for (int b = 0; b < numBranches; ++b) {
offset += 32;
branchArray[b] = new StandardTrieNode(source, offset, Math.min(offset + 32, limit));
}
this.branches = Bit32Array.of(IndexedArray.retained(branchArray), 1, 0, numBranches);
}
}
@Override
public Holder get(int branchIndex,
int valueIndex)
{
if (branchIndex == 0) {
return values.get(valueIndex);
} else {
final TrieNode branch = branches.get(branchIndex & 0x1f).getValueOrNull();
return (branch != null) ? branch.get(branchIndex >>> 5, valueIndex) : Holders.of();
}
}
@Override
public TrieNode assign(int branchIndex,
int valueIndex,
T value)
{
final Bit32Array> branches = this.branches;
final Bit32Array values = this.values;
if (branchIndex == 0) {
Bit32Array newValues = values.assign(valueIndex, value);
return (newValues == values) ? this : new StandardTrieNode(branches, values.assign(valueIndex, value));
} else {
final int childIndex = branchIndex & 0x1f;
final int childBranchIndex = branchIndex >>> 5;
TrieNode child = branches.get(childIndex).getValueOrNull();
if (child == null) {
return new StandardTrieNode(branches.assign(childIndex, new QuickTrieNode(childBranchIndex, valueIndex, value)), values);
} else {
return new StandardTrieNode(branches.assign(childIndex, child.assign(childBranchIndex, valueIndex, value)), values);
}
}
}
@Override
public TrieNode delete(int branchIndex,
int valueIndex)
{
final Bit32Array> branches = this.branches;
final Bit32Array values = this.values;
if (branchIndex == 0) {
return deleteValueImpl(valueIndex, branches, values);
} else {
final int childIndex = branchIndex & 0x1f;
TrieNode child = branches.get(childIndex).getValueOrNull();
if (child == null) {
return this;
}
TrieNode newChild = child.delete(branchIndex >>> 5, valueIndex);
if (newChild == child) {
return this;
} else if (newChild.shallowSize() == 0) {
if (branches.size() == 1 && values.size() == 0) {
return EmptyTrieNode.of();
} else {
return new StandardTrieNode(branches.delete(childIndex), values);
}
} else {
return new StandardTrieNode(branches.assign(childIndex, newChild), values);
}
}
}
private TrieNode deleteValueImpl(int valueIndex,
Bit32Array> branches,
Bit32Array values)
{
final Bit32Array newValues = values.delete(valueIndex);
if (newValues == values) {
return this;
}
if (branches.size() == 0) {
final int newSize = newValues.size();
if (newSize == 0) {
return EmptyTrieNode.of();
} else if (newSize == 1) {
final int remainingIndex = newValues.firstIndex();
return new QuickTrieNode(0, remainingIndex, newValues.get(remainingIndex).getValue());
}
}
return new StandardTrieNode(branches, newValues);
}
@Override
public Cursor cursor()
{
final Cursor valuesCursor = TransformCursor.ofValues(LazyCursor.of(values));
final Cursor branchesCursor = MultiTransformCursor.of(TransformCursor.ofValues(LazyCursor.of(branches)), new Func1, Cursor>()
{
@Override
public Cursor apply(TrieNode node)
{
return node.cursor();
}
});
return MultiCursor.of(valuesCursor, branchesCursor);
}
@Override
public int shallowSize()
{
return values.size() + branches.size();
}
@Override
public int deepSize()
{
int total = values.size();
for (JImmutableMap.Entry> branch : branches) {
total += branch.getValue().deepSize();
}
return total;
}
@Override
public JImmutableMap getNodeTypeCounts(JImmutableMap map)
{
map = super.getNodeTypeCounts(map);
for (JImmutableMap.Entry> branch : branches) {
map = branch.getValue().getNodeTypeCounts(map);
}
return map;
}
}