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Kotlin Immutable Collections multiplatform library
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/*
* Copyright 2016-2019 JetBrains s.r.o.
* Use of this source code is governed by the Apache 2.0 License that can be found in the LICENSE.txt file.
*/
package kotlinx.collections.immutable.implementations.immutableMap
import kotlinx.collections.immutable.internal.DeltaCounter
import kotlinx.collections.immutable.internal.MutabilityOwnership
import kotlinx.collections.immutable.internal.assert
import kotlinx.collections.immutable.internal.forEachOneBit
internal const val MAX_BRANCHING_FACTOR = 32
internal const val LOG_MAX_BRANCHING_FACTOR = 5
internal const val MAX_BRANCHING_FACTOR_MINUS_ONE = MAX_BRANCHING_FACTOR - 1
internal const val ENTRY_SIZE = 2
internal const val MAX_SHIFT = 30
/**
* Gets trie index segment of the specified [index] at the level specified by [shift].
*
* `shift` equal to zero corresponds to the root level.
* For each lower level `shift` increments by [LOG_MAX_BRANCHING_FACTOR].
*/
internal fun indexSegment(index: Int, shift: Int): Int =
(index shr shift) and MAX_BRANCHING_FACTOR_MINUS_ONE
private fun Array.insertEntryAtIndex(keyIndex: Int, key: K, value: V): Array {
val newBuffer = arrayOfNulls(this.size + ENTRY_SIZE)
this.copyInto(newBuffer, endIndex = keyIndex)
this.copyInto(newBuffer, keyIndex + ENTRY_SIZE, startIndex = keyIndex, endIndex = this.size)
newBuffer[keyIndex] = key
newBuffer[keyIndex + 1] = value
return newBuffer
}
private fun Array.replaceEntryWithNode(keyIndex: Int, nodeIndex: Int, newNode: TrieNode<*, *>): Array {
val newNodeIndex = nodeIndex - ENTRY_SIZE // place where to insert new node in the new buffer
val newBuffer = arrayOfNulls(this.size - ENTRY_SIZE + 1)
this.copyInto(newBuffer, endIndex = keyIndex)
this.copyInto(newBuffer, keyIndex, startIndex = keyIndex + ENTRY_SIZE, endIndex = nodeIndex)
newBuffer[newNodeIndex] = newNode
this.copyInto(newBuffer, newNodeIndex + 1, startIndex = nodeIndex, endIndex = this.size)
return newBuffer
}
private fun Array.replaceNodeWithEntry(nodeIndex: Int, keyIndex: Int, key: K, value: V): Array {
val newBuffer = this.copyOf(this.size + 1)
newBuffer.copyInto(newBuffer, nodeIndex + 2, nodeIndex + 1, this.size)
newBuffer.copyInto(newBuffer, keyIndex + 2, keyIndex , nodeIndex)
newBuffer[keyIndex] = key
newBuffer[keyIndex + 1] = value
return newBuffer
}
private fun Array.removeEntryAtIndex(keyIndex: Int): Array {
val newBuffer = arrayOfNulls(this.size - ENTRY_SIZE)
this.copyInto(newBuffer, endIndex = keyIndex)
this.copyInto(newBuffer, keyIndex, startIndex = keyIndex + ENTRY_SIZE, endIndex = this.size)
return newBuffer
}
private fun Array.removeNodeAtIndex(nodeIndex: Int): Array {
val newBuffer = arrayOfNulls(this.size - 1)
this.copyInto(newBuffer, endIndex = nodeIndex)
this.copyInto(newBuffer, nodeIndex, startIndex = nodeIndex + 1, endIndex = this.size)
return newBuffer
}
internal class TrieNode(
private var dataMap: Int,
private var nodeMap: Int,
buffer: Array,
private val ownedBy: MutabilityOwnership?
) {
constructor(dataMap: Int, nodeMap: Int, buffer: Array) : this(dataMap, nodeMap, buffer, null)
internal class ModificationResult(var node: TrieNode, val sizeDelta: Int) {
inline fun replaceNode(operation: (TrieNode) -> TrieNode): ModificationResult =
apply { node = operation(node) }
}
private fun asInsertResult() = ModificationResult(this, 1)
private fun asUpdateResult() = ModificationResult(this, 0)
internal var buffer: Array = buffer
private set
/** Returns number of entries stored in this trie node (not counting subnodes) */
internal fun entryCount(): Int = dataMap.countOneBits()
// here and later:
// positionMask — an int in form 2^n, i.e. having the single bit set, whose ordinal is a logical position in buffer
/** Returns true if the data bit map has the bit specified by [positionMask] set, indicating there's a data entry in the buffer at that position. */
internal fun hasEntryAt(positionMask: Int): Boolean {
return dataMap and positionMask != 0
}
/** Returns true if the node bit map has the bit specified by [positionMask] set, indicating there's a subtrie node in the buffer at that position. */
private fun hasNodeAt(positionMask: Int): Boolean {
return nodeMap and positionMask != 0
}
/** Gets the index in buffer of the data entry key corresponding to the position specified by [positionMask]. */
internal fun entryKeyIndex(positionMask: Int): Int {
return ENTRY_SIZE * (dataMap and (positionMask - 1)).countOneBits()
}
/** Gets the index in buffer of the subtrie node entry corresponding to the position specified by [positionMask]. */
internal fun nodeIndex(positionMask: Int): Int {
return buffer.size - 1 - (nodeMap and (positionMask - 1)).countOneBits()
}
/** Retrieves the buffer element at the given [keyIndex] as key of a data entry. */
private fun keyAtIndex(keyIndex: Int): K {
@Suppress("UNCHECKED_CAST")
return buffer[keyIndex] as K
}
/** Retrieves the buffer element next to the given [keyIndex] as value of a data entry. */
private fun valueAtKeyIndex(keyIndex: Int): V {
@Suppress("UNCHECKED_CAST")
return buffer[keyIndex + 1] as V
}
/** Retrieves the buffer element at the given [nodeIndex] as subtrie node. */
internal fun nodeAtIndex(nodeIndex: Int): TrieNode {
@Suppress("UNCHECKED_CAST")
return buffer[nodeIndex] as TrieNode
}
private fun insertEntryAt(positionMask: Int, key: K, value: V): TrieNode {
// assert(!hasEntryAt(positionMask))
val keyIndex = entryKeyIndex(positionMask)
val newBuffer = buffer.insertEntryAtIndex(keyIndex, key, value)
return TrieNode(dataMap or positionMask, nodeMap, newBuffer)
}
private fun mutableInsertEntryAt(positionMask: Int, key: K, value: V, owner: MutabilityOwnership): TrieNode {
// assert(!hasEntryAt(positionMask))
val keyIndex = entryKeyIndex(positionMask)
if (ownedBy === owner) {
buffer = buffer.insertEntryAtIndex(keyIndex, key, value)
dataMap = dataMap or positionMask
return this
}
val newBuffer = buffer.insertEntryAtIndex(keyIndex, key, value)
return TrieNode(dataMap or positionMask, nodeMap, newBuffer, owner)
}
private fun updateValueAtIndex(keyIndex: Int, value: V): TrieNode {
// assert(buffer[keyIndex + 1] !== value)
val newBuffer = buffer.copyOf()
newBuffer[keyIndex + 1] = value
return TrieNode(dataMap, nodeMap, newBuffer)
}
private fun mutableUpdateValueAtIndex(keyIndex: Int, value: V, mutator: PersistentHashMapBuilder): TrieNode {
// assert(buffer[keyIndex + 1] !== value)
// If the [mutator] is exclusive owner of this node, update value at specified index in-place.
if (ownedBy === mutator.ownership) {
buffer[keyIndex + 1] = value
return this
}
// Structural change due to node replacement.
mutator.modCount++
// Create new node with updated value at specified index.
val newBuffer = buffer.copyOf()
newBuffer[keyIndex + 1] = value
return TrieNode(dataMap, nodeMap, newBuffer, mutator.ownership)
}
/** The given [newNode] must not be a part of any persistent map instance. */
private fun updateNodeAtIndex(nodeIndex: Int, positionMask: Int, newNode: TrieNode): TrieNode {
// assert(buffer[nodeIndex] !== newNode)
val newNodeBuffer = newNode.buffer
if (newNodeBuffer.size == 2 && newNode.nodeMap == 0) {
if (buffer.size == 1) {
// assert(dataMap == 0 && nodeMap xor positionMask == 0)
newNode.dataMap = nodeMap
return newNode
}
val keyIndex = entryKeyIndex(positionMask)
val newBuffer = buffer.replaceNodeWithEntry(nodeIndex, keyIndex, newNodeBuffer[0], newNodeBuffer[1])
return TrieNode(dataMap xor positionMask, nodeMap xor positionMask, newBuffer)
}
val newBuffer = buffer.copyOf(buffer.size)
newBuffer[nodeIndex] = newNode
return TrieNode(dataMap, nodeMap, newBuffer)
}
/** The given [newNode] must not be a part of any persistent map instance. */
private fun mutableUpdateNodeAtIndex(nodeIndex: Int, newNode: TrieNode, owner: MutabilityOwnership): TrieNode {
assert(newNode.ownedBy === owner)
// assert(buffer[nodeIndex] !== newNode)
// nodes (including collision nodes) that have only one entry are upped if they have no siblings
if (buffer.size == 1 && newNode.buffer.size == ENTRY_SIZE && newNode.nodeMap == 0) {
// assert(dataMap == 0 && nodeMap xor positionMask == 0)
newNode.dataMap = nodeMap
return newNode
}
if (ownedBy === owner) {
buffer[nodeIndex] = newNode
return this
}
val newBuffer = buffer.copyOf()
newBuffer[nodeIndex] = newNode
return TrieNode(dataMap, nodeMap, newBuffer, owner)
}
private fun removeNodeAtIndex(nodeIndex: Int, positionMask: Int): TrieNode? {
// assert(hasNodeAt(positionMask))
if (buffer.size == 1) return null
val newBuffer = buffer.removeNodeAtIndex(nodeIndex)
return TrieNode(dataMap, nodeMap xor positionMask, newBuffer)
}
private fun mutableRemoveNodeAtIndex(nodeIndex: Int, positionMask: Int, owner: MutabilityOwnership): TrieNode? {
// assert(hasNodeAt(positionMask))
if (buffer.size == 1) return null
if (ownedBy === owner) {
buffer = buffer.removeNodeAtIndex(nodeIndex)
nodeMap = nodeMap xor positionMask
return this
}
val newBuffer = buffer.removeNodeAtIndex(nodeIndex)
return TrieNode(dataMap, nodeMap xor positionMask, newBuffer, owner)
}
private fun bufferMoveEntryToNode(keyIndex: Int, positionMask: Int, newKeyHash: Int,
newKey: K, newValue: V, shift: Int, owner: MutabilityOwnership?): Array {
val storedKey = keyAtIndex(keyIndex)
val storedKeyHash = storedKey.hashCode()
val storedValue = valueAtKeyIndex(keyIndex)
val newNode = makeNode(storedKeyHash, storedKey, storedValue,
newKeyHash, newKey, newValue, shift + LOG_MAX_BRANCHING_FACTOR, owner)
val nodeIndex = nodeIndex(positionMask) + 1 // place where to insert new node in the current buffer
return buffer.replaceEntryWithNode(keyIndex, nodeIndex, newNode)
}
private fun moveEntryToNode(keyIndex: Int, positionMask: Int, newKeyHash: Int,
newKey: K, newValue: V, shift: Int): TrieNode {
// assert(hasEntryAt(positionMask))
// assert(!hasNodeAt(positionMask))
val newBuffer = bufferMoveEntryToNode(keyIndex, positionMask, newKeyHash, newKey, newValue, shift, null)
return TrieNode(dataMap xor positionMask, nodeMap or positionMask, newBuffer)
}
private fun mutableMoveEntryToNode(keyIndex: Int, positionMask: Int, newKeyHash: Int,
newKey: K, newValue: V, shift: Int, owner: MutabilityOwnership): TrieNode {
// assert(hasEntryAt(positionMask))
// assert(!hasNodeAt(positionMask))
if (ownedBy === owner) {
buffer = bufferMoveEntryToNode(keyIndex, positionMask, newKeyHash, newKey, newValue, shift, owner)
dataMap = dataMap xor positionMask
nodeMap = nodeMap or positionMask
return this
}
val newBuffer = bufferMoveEntryToNode(keyIndex, positionMask, newKeyHash, newKey, newValue, shift, owner)
return TrieNode(dataMap xor positionMask, nodeMap or positionMask, newBuffer, owner)
}
/** Creates a new TrieNode for holding two given key value entries */
private fun makeNode(keyHash1: Int, key1: K, value1: V,
keyHash2: Int, key2: K, value2: V, shift: Int, owner: MutabilityOwnership?): TrieNode {
if (shift > MAX_SHIFT) {
// assert(key1 != key2)
// when two key hashes are entirely equal: the last level subtrie node stores them just as unordered list
return TrieNode(0, 0, arrayOf(key1, value1, key2, value2), owner)
}
val setBit1 = indexSegment(keyHash1, shift)
val setBit2 = indexSegment(keyHash2, shift)
if (setBit1 != setBit2) {
val nodeBuffer = if (setBit1 < setBit2) {
arrayOf(key1, value1, key2, value2)
} else {
arrayOf(key2, value2, key1, value1)
}
return TrieNode((1 shl setBit1) or (1 shl setBit2), 0, nodeBuffer, owner)
}
// hash segments at the given shift are equal: move these entries into the subtrie
val node = makeNode(keyHash1, key1, value1, keyHash2, key2, value2, shift + LOG_MAX_BRANCHING_FACTOR, owner)
return TrieNode(0, 1 shl setBit1, arrayOf(node), owner)
}
private fun removeEntryAtIndex(keyIndex: Int, positionMask: Int): TrieNode? {
// assert(hasEntryAt(positionMask))
if (buffer.size == ENTRY_SIZE) return null
val newBuffer = buffer.removeEntryAtIndex(keyIndex)
return TrieNode(dataMap xor positionMask, nodeMap, newBuffer)
}
private fun mutableRemoveEntryAtIndex(keyIndex: Int, positionMask: Int, mutator: PersistentHashMapBuilder): TrieNode? {
// assert(hasEntryAt(positionMask))
mutator.size--
mutator.operationResult = valueAtKeyIndex(keyIndex)
if (buffer.size == ENTRY_SIZE) return null
if (ownedBy === mutator.ownership) {
buffer = buffer.removeEntryAtIndex(keyIndex)
dataMap = dataMap xor positionMask
return this
}
val newBuffer = buffer.removeEntryAtIndex(keyIndex)
return TrieNode(dataMap xor positionMask, nodeMap, newBuffer, mutator.ownership)
}
private fun collisionRemoveEntryAtIndex(i: Int): TrieNode? {
if (buffer.size == ENTRY_SIZE) return null
val newBuffer = buffer.removeEntryAtIndex(i)
return TrieNode(0, 0, newBuffer)
}
private fun mutableCollisionRemoveEntryAtIndex(i: Int, mutator: PersistentHashMapBuilder): TrieNode? {
mutator.size--
mutator.operationResult = valueAtKeyIndex(i)
if (buffer.size == ENTRY_SIZE) return null
if (ownedBy === mutator.ownership) {
buffer = buffer.removeEntryAtIndex(i)
return this
}
val newBuffer = buffer.removeEntryAtIndex(i)
return TrieNode(0, 0, newBuffer, mutator.ownership)
}
private fun collisionKeyIndex(key: Any?): Int {
for (i in 0 until buffer.size step ENTRY_SIZE) {
if (key == keyAtIndex(i)) return i
}
return -1
}
private fun collisionContainsKey(key: K): Boolean {
return collisionKeyIndex(key) != -1
}
private fun collisionGet(key: K): V? {
val keyIndex = collisionKeyIndex(key)
return if (keyIndex != -1) valueAtKeyIndex(keyIndex) else null
}
private fun collisionPut(key: K, value: V): ModificationResult? {
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1) {
if (value === valueAtKeyIndex(keyIndex)) {
return null
}
val newBuffer = buffer.copyOf()
newBuffer[keyIndex + 1] = value
return TrieNode(0, 0, newBuffer).asUpdateResult()
}
val newBuffer = buffer.insertEntryAtIndex(0, key, value)
return TrieNode(0, 0, newBuffer).asInsertResult()
}
private fun mutableCollisionPut(key: K, value: V, mutator: PersistentHashMapBuilder): TrieNode {
// Check if there is an entry with the specified key.
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1) { // found entry with the specified key
mutator.operationResult = valueAtKeyIndex(keyIndex)
// If the [mutator] is exclusive owner of this node, update value of the entry in-place.
if (ownedBy === mutator.ownership) {
buffer[keyIndex + 1] = value
return this
}
// Structural change due to node replacement.
mutator.modCount++
// Create new node with updated entry value.
val newBuffer = buffer.copyOf()
newBuffer[keyIndex + 1] = value
return TrieNode(0, 0, newBuffer, mutator.ownership)
}
// Create new collision node with the specified entry added to it.
mutator.size++
val newBuffer = buffer.insertEntryAtIndex(0, key, value)
return TrieNode(0, 0, newBuffer, mutator.ownership)
}
private fun collisionRemove(key: K): TrieNode? {
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1) {
return collisionRemoveEntryAtIndex(keyIndex)
}
return this
}
private fun mutableCollisionRemove(key: K, mutator: PersistentHashMapBuilder): TrieNode? {
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1) {
return mutableCollisionRemoveEntryAtIndex(keyIndex, mutator)
}
return this
}
private fun collisionRemove(key: K, value: V): TrieNode? {
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1 && value == valueAtKeyIndex(keyIndex)) {
return collisionRemoveEntryAtIndex(keyIndex)
}
return this
}
private fun mutableCollisionRemove(key: K, value: V, mutator: PersistentHashMapBuilder): TrieNode? {
val keyIndex = collisionKeyIndex(key)
if (keyIndex != -1 && value == valueAtKeyIndex(keyIndex)) {
return mutableCollisionRemoveEntryAtIndex(keyIndex, mutator)
}
return this
}
private fun mutableCollisionPutAll(otherNode: TrieNode,
intersectionCounter: DeltaCounter,
owner: MutabilityOwnership): TrieNode {
assert(nodeMap == 0)
assert(dataMap == 0)
assert(otherNode.nodeMap == 0)
assert(otherNode.dataMap == 0)
val tempBuffer = this.buffer.copyOf(newSize = this.buffer.size + otherNode.buffer.size)
var i = this.buffer.size
for (j in 0 until otherNode.buffer.size step ENTRY_SIZE) {
@Suppress("UNCHECKED_CAST")
if (!this.collisionContainsKey(otherNode.buffer[j] as K)) {
tempBuffer[i] = otherNode.buffer[j]
tempBuffer[i + 1] = otherNode.buffer[j + 1]
i += ENTRY_SIZE
} else intersectionCounter.count++
}
return when (val newSize = i) {
this.buffer.size -> this
otherNode.buffer.size -> otherNode
tempBuffer.size -> TrieNode(0, 0, tempBuffer, owner)
else -> TrieNode(0, 0, tempBuffer.copyOf(newSize), owner)
}
}
/**
* Updates the cell of this node at [positionMask] with entries from the cell of [otherNode] at [positionMask].
*/
private fun mutablePutAllFromOtherNodeCell(
otherNode: TrieNode,
positionMask: Int,
shift: Int,
intersectionCounter: DeltaCounter,
mutator: PersistentHashMapBuilder
): TrieNode = when {
this.hasNodeAt(positionMask) -> {
val targetNode = this.nodeAtIndex(nodeIndex(positionMask))
when {
otherNode.hasNodeAt(positionMask) -> {
val otherTargetNode = otherNode.nodeAtIndex(otherNode.nodeIndex(positionMask))
targetNode.mutablePutAll(otherTargetNode, shift + LOG_MAX_BRANCHING_FACTOR, intersectionCounter, mutator)
}
otherNode.hasEntryAt(positionMask) -> {
val keyIndex = otherNode.entryKeyIndex(positionMask)
val key = otherNode.keyAtIndex(keyIndex)
val value = otherNode.valueAtKeyIndex(keyIndex)
val oldSize = mutator.size
targetNode.mutablePut(key.hashCode(), key, value, shift + LOG_MAX_BRANCHING_FACTOR, mutator).also {
if (mutator.size == oldSize) intersectionCounter.count++
}
}
else -> targetNode
}
}
otherNode.hasNodeAt(positionMask) -> {
val otherTargetNode = otherNode.nodeAtIndex(otherNode.nodeIndex(positionMask))
when {
this.hasEntryAt(positionMask) -> {
// if otherTargetNode already has a value associated with the key, do not put this entry
val keyIndex = this.entryKeyIndex(positionMask)
val key = this.keyAtIndex(keyIndex)
if (otherTargetNode.containsKey(key.hashCode(), key, shift + LOG_MAX_BRANCHING_FACTOR)) {
intersectionCounter.count++
otherTargetNode
} else {
val value = this.valueAtKeyIndex(keyIndex)
otherTargetNode.mutablePut(key.hashCode(), key, value, shift + LOG_MAX_BRANCHING_FACTOR, mutator)
}
}
else -> otherTargetNode
}
}
else -> { // two entries, and they are not equal by key. See (**) in mutablePutAll
val thisKeyIndex = this.entryKeyIndex(positionMask)
val thisKey = this.keyAtIndex(thisKeyIndex)
val thisValue = this.valueAtKeyIndex(thisKeyIndex)
val otherKeyIndex = otherNode.entryKeyIndex(positionMask)
val otherKey = otherNode.keyAtIndex(otherKeyIndex)
val otherValue = otherNode.valueAtKeyIndex(otherKeyIndex)
makeNode(
thisKey.hashCode(),
thisKey,
thisValue,
otherKey.hashCode(),
otherKey,
otherValue,
shift + LOG_MAX_BRANCHING_FACTOR,
mutator.ownership
)
}
}
private fun calculateSize(): Int {
if (nodeMap == 0) return buffer.size / ENTRY_SIZE
val numValues = dataMap.countOneBits()
var result = numValues
for(i in (numValues * ENTRY_SIZE) until buffer.size) {
result += nodeAtIndex(i).calculateSize()
}
return result
}
private fun elementsIdentityEquals(otherNode: TrieNode): Boolean {
if (this === otherNode) return true
if (nodeMap != otherNode.nodeMap) return false
if (dataMap != otherNode.dataMap) return false
for (i in 0 until buffer.size) {
if(buffer[i] !== otherNode.buffer[i]) return false
}
return true
}
fun containsKey(keyHash: Int, key: K, shift: Int): Boolean {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
return key == keyAtIndex(entryKeyIndex(keyPositionMask))
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val targetNode = nodeAtIndex(nodeIndex(keyPositionMask))
if (shift == MAX_SHIFT) {
return targetNode.collisionContainsKey(key)
}
return targetNode.containsKey(keyHash, key, shift + LOG_MAX_BRANCHING_FACTOR)
}
// key is absent
return false
}
fun get(keyHash: Int, key: K, shift: Int): V? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex)) {
return valueAtKeyIndex(keyIndex)
}
return null
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val targetNode = nodeAtIndex(nodeIndex(keyPositionMask))
if (shift == MAX_SHIFT) {
return targetNode.collisionGet(key)
}
return targetNode.get(keyHash, key, shift + LOG_MAX_BRANCHING_FACTOR)
}
// key is absent
return null
}
fun mutablePutAll(otherNode: TrieNode,
shift: Int,
intersectionCounter: DeltaCounter,
mutator: PersistentHashMapBuilder): TrieNode {
if (this === otherNode) {
intersectionCounter += calculateSize()
return this
}
// the collision case
if (shift > MAX_SHIFT) {
return mutableCollisionPutAll(otherNode, intersectionCounter, mutator.ownership)
}
// new nodes are where either of the old ones were
var newNodeMap = nodeMap or otherNode.nodeMap
// entries stay being entries only if one bits were in exactly one of input nodes
// but not in the new data nodes
var newDataMap = dataMap xor otherNode.dataMap and newNodeMap.inv()
// (**) now, this is tricky: we have a number of entry-entry pairs and we don't know yet whether
// they result in an entry (if keys are equal) or a new node (if they are not)
// but we want to keep it to single allocation, so we check and mark equal ones here
(dataMap and otherNode.dataMap).forEachOneBit { positionMask, _ ->
val leftKey = this.keyAtIndex(this.entryKeyIndex(positionMask))
val rightKey = otherNode.keyAtIndex(otherNode.entryKeyIndex(positionMask))
// if they are equal, put them in the data map
if (leftKey == rightKey) newDataMap = newDataMap or positionMask
// if they are not, put them in the node map
else newNodeMap = newNodeMap or positionMask
// we can use this later to skip calling equals() again
}
check(newNodeMap and newDataMap == 0)
val mutableNode = when {
this.ownedBy == mutator.ownership && this.dataMap == newDataMap && this.nodeMap == newNodeMap -> this
else -> {
val newBuffer = arrayOfNulls(newDataMap.countOneBits() * ENTRY_SIZE + newNodeMap.countOneBits())
TrieNode(newDataMap, newNodeMap, newBuffer)
}
}
newNodeMap.forEachOneBit { positionMask, index ->
val newNodeIndex = mutableNode.buffer.size - 1 - index
mutableNode.buffer[newNodeIndex] = mutablePutAllFromOtherNodeCell(otherNode, positionMask, shift, intersectionCounter, mutator)
}
newDataMap.forEachOneBit { positionMask, index ->
val newKeyIndex = index * ENTRY_SIZE
when {
!otherNode.hasEntryAt(positionMask) -> {
val oldKeyIndex = this.entryKeyIndex(positionMask)
mutableNode.buffer[newKeyIndex] = this.keyAtIndex(oldKeyIndex)
mutableNode.buffer[newKeyIndex + 1] = this.valueAtKeyIndex(oldKeyIndex)
}
// there is either only one entry in otherNode, or
// both entries are here => they are equal, see ** above
// so just overwrite that
else -> {
val oldKeyIndex = otherNode.entryKeyIndex(positionMask)
mutableNode.buffer[newKeyIndex] = otherNode.keyAtIndex(oldKeyIndex)
mutableNode.buffer[newKeyIndex + 1] = otherNode.valueAtKeyIndex(oldKeyIndex)
if (this.hasEntryAt(positionMask)) intersectionCounter.count++
}
}
}
return when {
this.elementsIdentityEquals(mutableNode) -> this
otherNode.elementsIdentityEquals(mutableNode) -> otherNode
else -> mutableNode
}
}
fun put(keyHash: Int, key: K, value: @UnsafeVariance V, shift: Int): ModificationResult? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex)) {
if (valueAtKeyIndex(keyIndex) === value) return null
return updateValueAtIndex(keyIndex, value).asUpdateResult()
}
return moveEntryToNode(keyIndex, keyPositionMask, keyHash, key, value, shift).asInsertResult()
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val putResult = if (shift == MAX_SHIFT) {
targetNode.collisionPut(key, value) ?: return null
} else {
targetNode.put(keyHash, key, value, shift + LOG_MAX_BRANCHING_FACTOR) ?: return null
}
return putResult.replaceNode { node -> updateNodeAtIndex(nodeIndex, keyPositionMask, node) }
}
// no entry at this key hash segment
return insertEntryAt(keyPositionMask, key, value).asInsertResult()
}
fun mutablePut(keyHash: Int, key: K, value: @UnsafeVariance V, shift: Int, mutator: PersistentHashMapBuilder): TrieNode {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex)) {
mutator.operationResult = valueAtKeyIndex(keyIndex)
if (valueAtKeyIndex(keyIndex) === value) {
return this
}
return mutableUpdateValueAtIndex(keyIndex, value, mutator)
}
mutator.size++
return mutableMoveEntryToNode(keyIndex, keyPositionMask, keyHash, key, value, shift, mutator.ownership)
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val newNode = if (shift == MAX_SHIFT) {
targetNode.mutableCollisionPut(key, value, mutator)
} else {
targetNode.mutablePut(keyHash, key, value, shift + LOG_MAX_BRANCHING_FACTOR, mutator)
}
if (targetNode === newNode) {
return this
}
return mutableUpdateNodeAtIndex(nodeIndex, newNode, mutator.ownership)
}
// key is absent
mutator.size++
return mutableInsertEntryAt(keyPositionMask, key, value, mutator.ownership)
}
fun remove(keyHash: Int, key: K, shift: Int): TrieNode? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex)) {
return removeEntryAtIndex(keyIndex, keyPositionMask)
}
return this
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val newNode = if (shift == MAX_SHIFT) {
targetNode.collisionRemove(key)
} else {
targetNode.remove(keyHash, key, shift + LOG_MAX_BRANCHING_FACTOR)
}
return replaceNode(targetNode, newNode, nodeIndex, keyPositionMask)
}
// key is absent
return this
}
private fun replaceNode(targetNode: TrieNode, newNode: TrieNode?, nodeIndex: Int, positionMask: Int) = when {
newNode == null ->
removeNodeAtIndex(nodeIndex, positionMask)
targetNode !== newNode ->
updateNodeAtIndex(nodeIndex, positionMask, newNode)
else ->
this
}
fun mutableRemove(keyHash: Int, key: K, shift: Int, mutator: PersistentHashMapBuilder): TrieNode? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex)) {
return mutableRemoveEntryAtIndex(keyIndex, keyPositionMask, mutator)
}
return this
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val newNode = if (shift == MAX_SHIFT) {
targetNode.mutableCollisionRemove(key, mutator)
} else {
targetNode.mutableRemove(keyHash, key, shift + LOG_MAX_BRANCHING_FACTOR, mutator)
}
return mutableReplaceNode(targetNode, newNode, nodeIndex, keyPositionMask, mutator.ownership)
}
// key is absent
return this
}
private fun mutableReplaceNode(targetNode: TrieNode, newNode: TrieNode?, nodeIndex: Int, positionMask: Int, owner: MutabilityOwnership) = when {
newNode == null ->
mutableRemoveNodeAtIndex(nodeIndex, positionMask, owner)
targetNode !== newNode ->
mutableUpdateNodeAtIndex(nodeIndex, newNode, owner)
else -> this
}
fun remove(keyHash: Int, key: K, value: @UnsafeVariance V, shift: Int): TrieNode? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex) && value == valueAtKeyIndex(keyIndex)) {
return removeEntryAtIndex(keyIndex, keyPositionMask)
}
return this
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val newNode = if (shift == MAX_SHIFT) {
targetNode.collisionRemove(key, value)
} else {
targetNode.remove(keyHash, key, value, shift + LOG_MAX_BRANCHING_FACTOR)
}
return replaceNode(targetNode, newNode, nodeIndex, keyPositionMask)
}
// key is absent
return this
}
fun mutableRemove(keyHash: Int, key: K, value: @UnsafeVariance V, shift: Int, mutator: PersistentHashMapBuilder): TrieNode? {
val keyPositionMask = 1 shl indexSegment(keyHash, shift)
if (hasEntryAt(keyPositionMask)) { // key is directly in buffer
val keyIndex = entryKeyIndex(keyPositionMask)
if (key == keyAtIndex(keyIndex) && value == valueAtKeyIndex(keyIndex)) {
return mutableRemoveEntryAtIndex(keyIndex, keyPositionMask, mutator)
}
return this
}
if (hasNodeAt(keyPositionMask)) { // key is in node
val nodeIndex = nodeIndex(keyPositionMask)
val targetNode = nodeAtIndex(nodeIndex)
val newNode = if (shift == MAX_SHIFT) {
targetNode.mutableCollisionRemove(key, value, mutator)
} else {
targetNode.mutableRemove(keyHash, key, value, shift + LOG_MAX_BRANCHING_FACTOR, mutator)
}
return mutableReplaceNode(targetNode, newNode, nodeIndex, keyPositionMask, mutator.ownership)
}
// key is absent
return this
}
internal fun equalsWith(that: TrieNode, equalityComparator: (V, V1) -> Boolean): Boolean {
if (this === that) return true
if (dataMap != that.dataMap || nodeMap != that.nodeMap) return false
if (dataMap == 0 && nodeMap == 0) { // collision node
if (buffer.size != that.buffer.size) return false
return (0 until buffer.size step ENTRY_SIZE).all { i ->
val thatKey = that.keyAtIndex(i)
val thatValue = that.valueAtKeyIndex(i)
val keyIndex = collisionKeyIndex(thatKey)
if (keyIndex != -1) {
val value = valueAtKeyIndex(keyIndex)
equalityComparator(value, thatValue)
} else false
}
}
val valueSize = dataMap.countOneBits() * ENTRY_SIZE
for (i in 0 until valueSize step ENTRY_SIZE) {
if (keyAtIndex(i) != that.keyAtIndex(i)) return false
if (!equalityComparator(valueAtKeyIndex(i), that.valueAtKeyIndex(i))) return false
}
for (i in valueSize until buffer.size) {
if (!nodeAtIndex(i).equalsWith(that.nodeAtIndex(i), equalityComparator)) return false
}
return true
}
// For testing trie structure
internal fun accept(visitor: (node: TrieNode, shift: Int, hash: Int, dataMap: Int, nodeMap: Int) -> Unit) {
accept(visitor, 0, 0)
}
private fun accept(
visitor: (node: TrieNode, shift: Int, hash: Int, dataMap: Int, nodeMap: Int) -> Unit,
hash: Int,
shift: Int
) {
visitor(this, shift, hash, dataMap, nodeMap)
var nodePositions = nodeMap
while (nodePositions != 0) {
val mask = nodePositions.takeLowestOneBit()
// assert(hasNodeAt(mask))
val hashSegment = mask.countTrailingZeroBits()
val childNode = nodeAtIndex(nodeIndex(mask))
childNode.accept(visitor, hash + (hashSegment shl shift), shift + LOG_MAX_BRANCHING_FACTOR)
nodePositions -= mask
}
}
internal companion object {
internal val EMPTY = TrieNode(0, 0, emptyArray())
}
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