org.javimmutable.collections.hash.hamt.HamtBranchNode Maven / Gradle / Ivy
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package org.javimmutable.collections.hash.hamt;
import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Cursorable;
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.SplitableIterable;
import org.javimmutable.collections.SplitableIterator;
import org.javimmutable.collections.common.ArrayHelper;
import org.javimmutable.collections.common.MutableDelta;
import org.javimmutable.collections.cursors.LazyMultiCursor;
import org.javimmutable.collections.cursors.SingleValueCursor;
import org.javimmutable.collections.cursors.StandardCursor;
import org.javimmutable.collections.hash.collision_map.CollisionMap;
import org.javimmutable.collections.iterators.EmptyIterator;
import org.javimmutable.collections.iterators.LazyMultiIterator;
import org.javimmutable.collections.iterators.SingleValueIterator;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
@Immutable
public class HamtBranchNode
implements ArrayHelper.Allocator>,
HamtNode
{
private static final HamtBranchNode[] EMPTY_NODES = new HamtBranchNode[0];
static final int SHIFT = 5;
static final int MASK = 0x1f;
private final int bitmask;
@Nullable
private final T value;
@Nonnull
private final HamtNode[] children;
private HamtBranchNode(int bitmask,
@Nullable T value,
@Nonnull HamtNode[] children)
{
this.bitmask = bitmask;
this.value = value;
this.children = children;
}
@SuppressWarnings("unchecked")
static HamtNode forLeafExpansion(int hashCode,
@Nonnull T value)
{
if (hashCode == 0) {
return new HamtBranchNode<>(0, value, EMPTY_NODES);
} else {
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final HamtNode[] children = new HamtNode[1];
children[0] = forLeafExpansion(remainder, value);
return new HamtBranchNode<>(bit, null, children);
}
}
@Override
public Holder find(@Nonnull CollisionMap collisionMap,
int hashCode,
@Nonnull K hashKey)
{
if (hashCode == 0) {
if (value != null) {
return collisionMap.findValue(value, hashKey);
} else {
return Holders.of();
}
}
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final int bitmask = this.bitmask;
if ((bitmask & bit) == 0) {
return Holders.of();
} else {
final int childIndex = realIndex(bitmask, bit);
return children[childIndex].find(collisionMap, remainder, hashKey);
}
}
@Override
public V getValueOr(@Nonnull CollisionMap collisionMap,
int hashCode,
@Nonnull K hashKey,
V defaultValue)
{
if (hashCode == 0) {
if (value != null) {
return collisionMap.getValueOr(value, hashKey, defaultValue);
} else {
return defaultValue;
}
}
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final int bitmask = this.bitmask;
if ((bitmask & bit) == 0) {
return defaultValue;
} else {
final int childIndex = realIndex(bitmask, bit);
return children[childIndex].getValueOr(collisionMap, remainder, hashKey, defaultValue);
}
}
@Override
@Nonnull
public HamtNode assign(@Nonnull CollisionMap collisionMap,
int hashCode,
@Nonnull K hashKey,
@Nullable V value,
@Nonnull MutableDelta sizeDelta)
{
final HamtNode[] children = this.children;
final int bitmask = this.bitmask;
final T thisValue = this.value;
if (hashCode == 0) {
final T newValue = collisionMap.update(thisValue, hashKey, value, sizeDelta);
if (thisValue == newValue) {
return this;
} else {
return new HamtBranchNode<>(bitmask, newValue, children);
}
}
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final int childIndex = realIndex(bitmask, bit);
if ((bitmask & bit) == 0) {
final HamtNode newChild = new HamtLeafNode<>(remainder, collisionMap.update(null, hashKey, value, sizeDelta));
final HamtNode[] newChildren = ArrayHelper.insert(this, children, childIndex, newChild);
return new HamtBranchNode<>(bitmask | bit, thisValue, newChildren);
} else {
final HamtNode child = children[childIndex];
final HamtNode newChild = child.assign(collisionMap, remainder, hashKey, value, sizeDelta);
if (newChild == child) {
return this;
} else {
final HamtNode[] newChildren = ArrayHelper.assign(children, childIndex, newChild);
return new HamtBranchNode<>(bitmask, thisValue, newChildren);
}
}
}
@Nonnull
@Override
public HamtNode update(@Nonnull CollisionMap collisionMap,
int hashCode,
@Nonnull K hashKey,
@Nonnull Func1, V> generator,
@Nonnull MutableDelta sizeDelta)
{
final HamtNode[] children = this.children;
final int bitmask = this.bitmask;
final T thisValue = this.value;
if (hashCode == 0) {
final T newValue = collisionMap.update(thisValue, hashKey, generator, sizeDelta);
if (thisValue == newValue) {
return this;
} else {
return new HamtBranchNode<>(bitmask, newValue, children);
}
}
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final int childIndex = realIndex(bitmask, bit);
if ((bitmask & bit) == 0) {
final HamtNode newChild = new HamtLeafNode<>(remainder, collisionMap.update(null, hashKey, generator, sizeDelta));
final HamtNode[] newChildren = ArrayHelper.insert(this, children, childIndex, newChild);
return new HamtBranchNode<>(bitmask | bit, thisValue, newChildren);
} else {
final HamtNode child = children[childIndex];
final HamtNode newChild = child.update(collisionMap, remainder, hashKey, generator, sizeDelta);
if (newChild == child) {
return this;
} else {
final HamtNode[] newChildren = ArrayHelper.assign(children, childIndex, newChild);
return new HamtBranchNode<>(bitmask, thisValue, newChildren);
}
}
}
@Override
@Nonnull
public HamtNode delete(@Nonnull CollisionMap collisionMap,
int hashCode,
@Nonnull K hashKey,
@Nonnull MutableDelta sizeDelta)
{
final int bitmask = this.bitmask;
final HamtNode[] children = this.children;
final T value = this.value;
if (hashCode == 0) {
if (value != null) {
final T newValue = collisionMap.delete(value, hashKey, sizeDelta);
if (newValue == value) {
return this;
} else if (newValue == null) {
if (bitmask == 0) {
return HamtEmptyNode.of();
} else {
return createForDelete(bitmask, null, children);
}
} else {
return new HamtBranchNode<>(bitmask, newValue, children);
}
} else {
return this;
}
}
final int index = hashCode & MASK;
final int remainder = hashCode >>> SHIFT;
final int bit = 1 << index;
final int childIndex = realIndex(bitmask, bit);
if ((bitmask & bit) == 0) {
return this;
} else {
final HamtNode child = children[childIndex];
final HamtNode newChild = child.delete(collisionMap, remainder, hashKey, sizeDelta);
if (newChild == child) {
return this;
} else if (newChild.isEmpty()) {
if (children.length == 1) {
if (value == null) {
return HamtEmptyNode.of();
} else {
return new HamtLeafNode<>(0, value);
}
} else {
final HamtNode[] newChildren = ArrayHelper.delete(this, children, childIndex);
return createForDelete(bitmask & ~bit, value, newChildren);
}
} else {
final HamtNode[] newChildren = ArrayHelper.assign(children, childIndex, newChild);
return createForDelete(bitmask, value, newChildren);
}
}
}
private HamtNode createForDelete(int bitmask,
T value,
@Nonnull HamtNode[] children)
{
if ((value == null) && (children.length == 1)) {
final HamtNode child = children[0];
if (child instanceof HamtLeafNode) {
final HamtLeafNode leaf = (HamtLeafNode)child;
return leaf.liftNode(Integer.numberOfTrailingZeros(bitmask));
}
if (child instanceof HamtBranchNode) {
final HamtBranchNode branch = (HamtBranchNode)child;
if (branch.value != null && branch.children.length == 0) {
return new HamtLeafNode<>(Integer.numberOfTrailingZeros(bitmask), branch.value);
}
}
}
return new HamtBranchNode<>(bitmask, value, children);
}
@Override
public boolean isEmpty()
{
return bitmask == 0 && value == null;
}
private static int realIndex(int bitmask,
int bit)
{
return Integer.bitCount(bitmask & (bit - 1));
}
@SuppressWarnings("unchecked")
@Nonnull
@Override
public HamtNode[] allocate(int size)
{
return new HamtNode[size];
}
@Override
@Nonnull
public SplitableIterator> iterator(CollisionMap collisionMap)
{
return LazyMultiIterator.transformed(indexedForIterator(), node -> () -> iteratorHelper(node.iterator(), collisionMap));
}
@Nonnull
private SplitableIterator> iteratorHelper(SplitableIterator value,
CollisionMap collisionMap)
{
return LazyMultiIterator.transformed(value, t -> () -> collisionMap.iterator(t));
}
@Nonnull
@Override
public SplitableIterator iterator()
{
return LazyMultiIterator.iterator(indexedForIterator());
}
@Override
@Nonnull
public Cursor> cursor(CollisionMap collisionMap)
{
return LazyMultiCursor.transformed(indexedForCursor(), node -> () -> cursorHelper(node.cursor(), collisionMap));
}
@Nonnull
private Cursor> cursorHelper(Cursor value,
CollisionMap collisionMap)
{
return LazyMultiCursor.transformed(value, t -> () -> collisionMap.cursor(t));
}
@Nonnull
@Override
public Cursor cursor()
{
return LazyMultiCursor.cursor(indexedForCursor());
}
@Override
public String toString()
{
return "(" + value + ",0x" + Integer.toHexString(bitmask) + "," + children.length + ")";
}
@Override
public void checkInvariants()
{
if ((value == null) && (children.length == 1)) {
if (children[0] instanceof HamtLeafNode) {
// we should have replaced ourselves with a leaf
throw new IllegalStateException();
}
}
for (HamtNode child : children) {
child.checkInvariants();
}
}
private Indexed> indexedForIterator()
{
return new Indexed>()
{
@Override
public SplitableIterable get(int index)
{
if (index == 0) {
if (value != null) {
return () -> SingleValueIterator.of(value);
} else {
return () -> EmptyIterator.of();
}
} else {
return children[index - 1];
}
}
@Override
public int size()
{
return children.length + 1;
}
};
}
private Indexed> indexedForCursor()
{
return new Indexed>()
{
@Override
public Cursorable get(int index)
{
if (index == 0) {
if (value != null) {
return () -> SingleValueCursor.of(value);
} else {
return () -> StandardCursor.of();
}
} else {
return children[index - 1];
}
}
@Override
public int size()
{
return children.length + 1;
}
};
}
}
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