/**
* Copyright (c) Rich Hickey. All rights reserved.
* The use and distribution terms for this software are covered by the
* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
* which can be found in the file epl-v10.html at the root of this distribution.
* By using this software in any fashion, you are agreeing to be bound by
* the terms of this license.
* You must not remove this notice, or any other, from this software.
**/
package clojure.lang;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;
/*
A persistent rendition of Phil Bagwell's Hash Array Mapped Trie
Uses path copying for persistence
HashCollision leaves vs. extended hashing
Node polymorphism vs. conditionals
No sub-tree pools or root-resizing
Any errors are my own
*/
public class PersistentHashMap extends APersistentMap implements IEditableCollection {
final int count;
final INode root;
final boolean hasNull;
final Object nullValue;
final public static PersistentHashMap EMPTY = new PersistentHashMap(0, null, false, null);
final private static Object NOT_FOUND = new Object();
static public IPersistentMap create(Map other){
ITransientMap ret = EMPTY.asTransient();
for(Object o : other.entrySet())
{
Map.Entry e = (Entry) o;
ret = ret.assoc(e.getKey(), e.getValue());
}
return ret.persistent();
}
/*
* @param init {key1,val1,key2,val2,...}
*/
public static PersistentHashMap create(Object... init){
ITransientMap ret = EMPTY.asTransient();
for(int i = 0; i < init.length; i += 2)
{
ret = ret.assoc(init[i], init[i + 1]);
}
return (PersistentHashMap) ret.persistent();
}
public static PersistentHashMap create(List init){
ITransientMap ret = EMPTY.asTransient();
for(Iterator i = init.iterator(); i.hasNext();)
{
Object key = i.next();
if(!i.hasNext())
throw new IllegalArgumentException(String.format("No value supplied for key: %s", key));
Object val = i.next();
ret = ret.assoc(key, val);
}
return (PersistentHashMap) ret.persistent();
}
static public PersistentHashMap create(ISeq items){
ITransientMap ret = EMPTY.asTransient();
for(; items != null; items = items.next().next())
{
if(items.next() == null)
throw new IllegalArgumentException(String.format("No value supplied for key: %s", items.first()));
ret = ret.assoc(items.first(), RT.second(items));
}
return (PersistentHashMap) ret.persistent();
}
/*
* @param init {key1,val1,key2,val2,...}
*/
public static PersistentHashMap create(IPersistentMap meta, Object... init){
return create(init).withMeta(meta);
}
PersistentHashMap(int count, INode root, boolean hasNull, Object nullValue){
this.count = count;
this.root = root;
this.hasNull = hasNull;
this.nullValue = nullValue;
}
public PersistentHashMap(IPersistentMap meta, int count, INode root, boolean hasNull, Object nullValue){
super(meta);
this.count = count;
this.root = root;
this.hasNull = hasNull;
this.nullValue = nullValue;
}
public boolean containsKey(Object key){
if(key == null)
return hasNull;
return (root != null) ? root.find(0, Util.hash(key), key, NOT_FOUND) != NOT_FOUND : false;
}
public IMapEntry entryAt(Object key){
if(key == null)
return hasNull ? new MapEntry(null, nullValue) : null;
return (root != null) ? root.find(0, Util.hash(key), key) : null;
}
public IPersistentMap assoc(Object key, Object val){
if(key == null) {
if(hasNull && val == nullValue)
return this;
return new PersistentHashMap(meta(), hasNull ? count : count + 1, root, true, val);
}
Box addedLeaf = new Box(null);
INode newroot = (root == null ? BitmapIndexedNode.EMPTY : root)
.assoc(0, Util.hash(key), key, val, addedLeaf);
if(newroot == root)
return this;
return new PersistentHashMap(meta(), addedLeaf.val == null ? count : count + 1, newroot, hasNull, nullValue);
}
public Object valAt(Object key, Object notFound){
if(key == null)
return hasNull ? nullValue : notFound;
return root != null ? root.find(0, Util.hash(key), key, notFound) : notFound;
}
public Object valAt(Object key){
return valAt(key, null);
}
public IPersistentMap assocEx(Object key, Object val) throws Exception{
if(containsKey(key))
throw new Exception("Key already present");
return assoc(key, val);
}
public IPersistentMap without(Object key){
if(key == null)
return hasNull ? new PersistentHashMap(meta(), count - 1, root, false, null) : this;
if(root == null)
return this;
INode newroot = root.without(0, Util.hash(key), key);
if(newroot == root)
return this;
return new PersistentHashMap(meta(), count - 1, newroot, hasNull, nullValue);
}
public Iterator iterator(){
return new SeqIterator(seq());
}
public int count(){
return count;
}
public ISeq seq(){
ISeq s = root != null ? root.nodeSeq() : null;
return hasNull ? new Cons(new MapEntry(null, nullValue), s) : s;
}
public IPersistentCollection empty(){
return EMPTY.withMeta(meta());
}
static int mask(int hash, int shift){
//return ((hash << shift) >>> 27);// & 0x01f;
return (hash >>> shift) & 0x01f;
}
public PersistentHashMap withMeta(IPersistentMap meta){
return new PersistentHashMap(meta, count, root, hasNull, nullValue);
}
public TransientHashMap asTransient() {
return new TransientHashMap(this);
}
static final class TransientHashMap extends ATransientMap {
AtomicReference<Thread> edit;
INode root;
int count;
boolean hasNull;
Object nullValue;
final Box leafFlag = new Box(null);
TransientHashMap(PersistentHashMap m) {
this(new AtomicReference<Thread>(Thread.currentThread()), m.root, m.count, m.hasNull, m.nullValue);
}
TransientHashMap(AtomicReference<Thread> edit, INode root, int count, boolean hasNull, Object nullValue) {
this.edit = edit;
this.root = root;
this.count = count;
this.hasNull = hasNull;
this.nullValue = nullValue;
}
ITransientMap doAssoc(Object key, Object val) {
if (key == null) {
if (this.nullValue != val)
this.nullValue = val;
if (!hasNull) {
this.count++;
this.hasNull = true;
}
return this;
}
// Box leafFlag = new Box(null);
leafFlag.val = null;
INode n = (root == null ? BitmapIndexedNode.EMPTY : root)
.assoc(edit, 0, Util.hash(key), key, val, leafFlag);
if (n != this.root)
this.root = n;
if(leafFlag.val != null) this.count++;
return this;
}
ITransientMap doWithout(Object key) {
if (key == null) {
if (!hasNull) return this;
hasNull = false;
nullValue = null;
this.count--;
return this;
}
if (root == null) return this;
// Box leafFlag = new Box(null);
leafFlag.val = null;
INode n = root.without(edit, 0, Util.hash(key), key, leafFlag);
if (n != root)
this.root = n;
if(leafFlag.val != null) this.count--;
return this;
}
IPersistentMap doPersistent() {
edit.set(null);
return new PersistentHashMap(count, root, hasNull, nullValue);
}
Object doValAt(Object key, Object notFound) {
if (key == null)
if (hasNull)
return nullValue;
else
return notFound;
if (root == null)
return null;
return root.find(0, Util.hash(key), key, notFound);
}
int doCount() {
return count;
}
void ensureEditable(){
Thread owner = edit.get();
if(owner == Thread.currentThread())
return;
if(owner != null)
throw new IllegalAccessError("Transient used by non-owner thread");
throw new IllegalAccessError("Transient used after persistent! call");
}
}
static interface INode{
INode assoc(int shift, int hash, Object key, Object val, Box addedLeaf);
INode without(int shift, int hash, Object key);
IMapEntry find(int shift, int hash, Object key);
Object find(int shift, int hash, Object key, Object notFound);
ISeq nodeSeq();
INode assoc(AtomicReference<Thread> edit, int shift, int hash, Object key, Object val, Box addedLeaf);
INode without(AtomicReference<Thread> edit, int shift, int hash, Object key, Box removedLeaf);
}
final static class ArrayNode implements INode{
int count;
final INode[] array;
final AtomicReference<Thread> edit;
ArrayNode(AtomicReference<Thread> edit, int count, INode[] array){
this.array = array;
this.edit = edit;
this.count = count;
}
public INode assoc(int shift, int hash, Object key, Object val, Box addedLeaf){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null)
return new ArrayNode(null, count + 1, cloneAndSet(array, idx, BitmapIndexedNode.EMPTY.assoc(shift + 5, hash, key, val, addedLeaf)));
INode n = node.assoc(shift + 5, hash, key, val, addedLeaf);
if(n == node)
return this;
return new ArrayNode(null, count, cloneAndSet(array, idx, n));
}
public INode without(int shift, int hash, Object key){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null)
return this;
INode n = node.without(shift + 5, hash, key);
if(n == node)
return this;
if (n == null) {
if (count <= 8) // shrink
return pack(null, idx);
return new ArrayNode(null, count - 1, cloneAndSet(array, idx, n));
} else
return new ArrayNode(null, count, cloneAndSet(array, idx, n));
}
public IMapEntry find(int shift, int hash, Object key){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null)
return null;
return node.find(shift + 5, hash, key);
}
public Object find(int shift, int hash, Object key, Object notFound){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null)
return notFound;
return node.find(shift + 5, hash, key, notFound);
}
public ISeq nodeSeq(){
return Seq.create(array);
}
private ArrayNode ensureEditable(AtomicReference<Thread> edit){
if(this.edit == edit)
return this;
return new ArrayNode(edit, count, this.array.clone());
}
private ArrayNode editAndSet(AtomicReference<Thread> edit, int i, INode n){
ArrayNode editable = ensureEditable(edit);
editable.array[i] = n;
return editable;
}
private INode pack(AtomicReference<Thread> edit, int idx) {
Object[] newArray = new Object[2*(count - 1)];
int j = 1;
int bitmap = 0;
for(int i = 0; i < idx; i++)
if (array[i] != null) {
newArray[j] = array[i];
bitmap |= 1 << i;
j += 2;
}
for(int i = idx + 1; i < array.length; i++)
if (array[i] != null) {
newArray[j] = array[i];
bitmap |= 1 << i;
j += 2;
}
return new BitmapIndexedNode(edit, bitmap, newArray);
}
public INode assoc(AtomicReference<Thread> edit, int shift, int hash, Object key, Object val, Box addedLeaf){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null) {
ArrayNode editable = editAndSet(edit, idx, BitmapIndexedNode.EMPTY.assoc(edit, shift + 5, hash, key, val, addedLeaf));
editable.count++;
return editable;
}
INode n = node.assoc(edit, shift + 5, hash, key, val, addedLeaf);
if(n == node)
return this;
return editAndSet(edit, idx, n);
}
public INode without(AtomicReference<Thread> edit, int shift, int hash, Object key, Box removedLeaf){
int idx = mask(hash, shift);
INode node = array[idx];
if(node == null)
return this;
INode n = node.without(edit, shift + 5, hash, key, removedLeaf);
if(n == node)
return this;
if(n == null) {
if (count <= 8) // shrink
return pack(edit, idx);
ArrayNode editable = editAndSet(edit, idx, n);
editable.count--;
return editable;
}
return editAndSet(edit, idx, n);
}
static class Seq extends ASeq {
final INode[] nodes;
final int i;
final ISeq s;
static ISeq create(INode[] nodes) {
return create(null, nodes, 0, null);
}
private static ISeq create(IPersistentMap meta, INode[] nodes, int i, ISeq s) {
if (s != null)
return new Seq(meta, nodes, i, s);
for(int j = i; j < nodes.length; j++)
if (nodes[j] != null) {
ISeq ns = nodes[j].nodeSeq();
if (ns != null)
return new Seq(meta, nodes, j + 1, ns);
}
return null;
}
private Seq(IPersistentMap meta, INode[] nodes, int i, ISeq s) {
super(meta);
this.nodes = nodes;
this.i = i;
this.s = s;
}
public Obj withMeta(IPersistentMap meta) {
return new Seq(meta, nodes, i, s);
}
public Object first() {
return s.first();
}
public ISeq next() {
return create(null, nodes, i, s.next());
}
}
}
final static class BitmapIndexedNode implements INode{
static final BitmapIndexedNode EMPTY = new BitmapIndexedNode(null, 0, new Object[0]);
int bitmap;
Object[] array;
final AtomicReference<Thread> edit;
final int index(int bit){
return Integer.bitCount(bitmap & (bit - 1));
}
BitmapIndexedNode(AtomicReference<Thread> edit, int bitmap, Object[] array){
this.bitmap = bitmap;
this.array = array;
this.edit = edit;
}
public INode assoc(int shift, int hash, Object key, Object val, Box addedLeaf){
int bit = bitpos(hash, shift);
int idx = index(bit);
if((bitmap & bit) != 0) {
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null) {
INode n = ((INode) valOrNode).assoc(shift + 5, hash, key, val, addedLeaf);
if(n == valOrNode)
return this;
return new BitmapIndexedNode(null, bitmap, cloneAndSet(array, 2*idx+1, n));
}
if(Util.equals(key, keyOrNull)) {
if(val == valOrNode)
return this;
return new BitmapIndexedNode(null, bitmap, cloneAndSet(array, 2*idx+1, val));
}
addedLeaf.val = addedLeaf;
return new BitmapIndexedNode(null, bitmap,
cloneAndSet(array,
2*idx, null,
2*idx+1, createNode(shift + 5, keyOrNull, valOrNode, hash, key, val)));
} else {
int n = Integer.bitCount(bitmap);
if(n >= 16) {
INode[] nodes = new INode[32];
int jdx = mask(hash, shift);
nodes[jdx] = EMPTY.assoc(shift + 5, hash, key, val, addedLeaf);
int j = 0;
for(int i = 0; i < 32; i++)
if(((bitmap >>> i) & 1) != 0) {
if (array[j] == null)
nodes[i] = (INode) array[j+1];
else
nodes[i] = EMPTY.assoc(shift + 5, Util.hash(array[j]), array[j], array[j+1], addedLeaf);
j += 2;
}
return new ArrayNode(null, n + 1, nodes);
} else {
Object[] newArray = new Object[2*(n+1)];
System.arraycopy(array, 0, newArray, 0, 2*idx);
newArray[2*idx] = key;
addedLeaf.val = addedLeaf;
newArray[2*idx+1] = val;
System.arraycopy(array, 2*idx, newArray, 2*(idx+1), 2*(n-idx));
return new BitmapIndexedNode(null, bitmap | bit, newArray);
}
}
}
public INode without(int shift, int hash, Object key){
int bit = bitpos(hash, shift);
if((bitmap & bit) == 0)
return this;
int idx = index(bit);
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null) {
INode n = ((INode) valOrNode).without(shift + 5, hash, key);
if (n == valOrNode)
return this;
if (n != null)
return new BitmapIndexedNode(null, bitmap, cloneAndSet(array, 2*idx+1, n));
if (bitmap == bit)
return null;
return new BitmapIndexedNode(null, bitmap ^ bit, removePair(array, idx));
}
if(Util.equals(key, keyOrNull))
// TODO: collapse
return new BitmapIndexedNode(null, bitmap ^ bit, removePair(array, idx));
return this;
}
public IMapEntry find(int shift, int hash, Object key){
int bit = bitpos(hash, shift);
if((bitmap & bit) == 0)
return null;
int idx = index(bit);
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null)
return ((INode) valOrNode).find(shift + 5, hash, key);
if(Util.equals(key, keyOrNull))
return new MapEntry(keyOrNull, valOrNode);
return null;
}
public Object find(int shift, int hash, Object key, Object notFound){
int bit = bitpos(hash, shift);
if((bitmap & bit) == 0)
return notFound;
int idx = index(bit);
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null)
return ((INode) valOrNode).find(shift + 5, hash, key, notFound);
if(Util.equals(key, keyOrNull))
return valOrNode;
return notFound;
}
public ISeq nodeSeq(){
return NodeSeq.create(array);
}
private BitmapIndexedNode ensureEditable(AtomicReference<Thread> edit){
if(this.edit == edit)
return this;
int n = Integer.bitCount(bitmap);
Object[] newArray = new Object[n >= 0 ? 2*(n+1) : 4]; // make room for next assoc
System.arraycopy(array, 0, newArray, 0, 2*n);
return new BitmapIndexedNode(edit, bitmap, newArray);
}
private BitmapIndexedNode editAndSet(AtomicReference<Thread> edit, int i, Object a) {
BitmapIndexedNode editable = ensureEditable(edit);
editable.array[i] = a;
return editable;
}
private BitmapIndexedNode editAndSet(AtomicReference<Thread> edit, int i, Object a, int j, Object b) {
BitmapIndexedNode editable = ensureEditable(edit);
editable.array[i] = a;
editable.array[j] = b;
return editable;
}
private BitmapIndexedNode editAndRemovePair(AtomicReference<Thread> edit, int bit, int i) {
if (bitmap == bit)
return null;
BitmapIndexedNode editable = ensureEditable(edit);
editable.bitmap ^= bit;
System.arraycopy(editable.array, 2*(i+1), editable.array, 2*i, editable.array.length - 2*(i+1));
editable.array[editable.array.length - 2] = null;
editable.array[editable.array.length - 1] = null;
return editable;
}
public INode assoc(AtomicReference<Thread> edit, int shift, int hash, Object key, Object val, Box addedLeaf){
int bit = bitpos(hash, shift);
int idx = index(bit);
if((bitmap & bit) != 0) {
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null) {
INode n = ((INode) valOrNode).assoc(edit, shift + 5, hash, key, val, addedLeaf);
if(n == valOrNode)
return this;
return editAndSet(edit, 2*idx+1, n);
}
if(Util.equals(key, keyOrNull)) {
if(val == valOrNode)
return this;
return editAndSet(edit, 2*idx+1, val);
}
addedLeaf.val = addedLeaf;
return editAndSet(edit, 2*idx, null, 2*idx+1,
createNode(edit, shift + 5, keyOrNull, valOrNode, hash, key, val));
} else {
int n = Integer.bitCount(bitmap);
if(n*2 < array.length) {
addedLeaf.val = addedLeaf;
BitmapIndexedNode editable = ensureEditable(edit);
System.arraycopy(editable.array, 2*idx, editable.array, 2*(idx+1), 2*(n-idx));
editable.array[2*idx] = key;
editable.array[2*idx+1] = val;
editable.bitmap |= bit;
return editable;
}
if(n >= 16) {
INode[] nodes = new INode[32];
int jdx = mask(hash, shift);
nodes[jdx] = EMPTY.assoc(edit, shift + 5, hash, key, val, addedLeaf);
int j = 0;
for(int i = 0; i < 32; i++)
if(((bitmap >>> i) & 1) != 0) {
if (array[j] == null)
nodes[i] = (INode) array[j+1];
else
nodes[i] = EMPTY.assoc(edit, shift + 5, Util.hash(array[j]), array[j], array[j+1], addedLeaf);
j += 2;
}
return new ArrayNode(edit, n + 1, nodes);
} else {
Object[] newArray = new Object[2*(n+4)];
System.arraycopy(array, 0, newArray, 0, 2*idx);
newArray[2*idx] = key;
addedLeaf.val = addedLeaf;
newArray[2*idx+1] = val;
System.arraycopy(array, 2*idx, newArray, 2*(idx+1), 2*(n-idx));
BitmapIndexedNode editable = ensureEditable(edit);
editable.array = newArray;
editable.bitmap |= bit;
return editable;
}
}
}
public INode without(AtomicReference<Thread> edit, int shift, int hash, Object key, Box removedLeaf){
int bit = bitpos(hash, shift);
if((bitmap & bit) == 0)
return this;
int idx = index(bit);
Object keyOrNull = array[2*idx];
Object valOrNode = array[2*idx+1];
if(keyOrNull == null) {
INode n = ((INode) valOrNode).without(edit, shift + 5, hash, key, removedLeaf);
if (n == valOrNode)
return this;
if (n != null)
return editAndSet(edit, 2*idx+1, n);
if (bitmap == bit)
return null;
removedLeaf.val = removedLeaf;
return editAndRemovePair(edit, bit, idx);
}
if(Util.equals(key, keyOrNull)) {
removedLeaf.val = removedLeaf;
// TODO: collapse
return editAndRemovePair(edit, bit, idx);
}
return this;
}
}
final static class HashCollisionNode implements INode{
final int hash;
int count;
Object[] array;
final AtomicReference<Thread> edit;
HashCollisionNode(AtomicReference<Thread> edit, int hash, int count, Object... array){
this.edit = edit;
this.hash = hash;
this.count = count;
this.array = array;
}
public INode assoc(int shift, int hash, Object key, Object val, Box addedLeaf){
if(hash == this.hash) {
int idx = findIndex(key);
if(idx != -1) {
if(array[idx + 1] == val)
return this;
return new HashCollisionNode(null, hash, count, cloneAndSet(array, idx + 1, val));
}
Object[] newArray = new Object[array.length + 2];
System.arraycopy(array, 0, newArray, 0, array.length);
newArray[array.length] = key;
newArray[array.length + 1] = val;
addedLeaf.val = addedLeaf;
return new HashCollisionNode(edit, hash, count + 1, newArray);
}
// nest it in a bitmap node
return new BitmapIndexedNode(null, bitpos(this.hash, shift), new Object[] {null, this})
.assoc(shift, hash, key, val, addedLeaf);
}
public INode without(int shift, int hash, Object key){
int idx = findIndex(key);
if(idx == -1)
return this;
if(count == 1)
return null;
return new HashCollisionNode(null, hash, count - 1, removePair(array, idx/2));
}
public IMapEntry find(int shift, int hash, Object key){
int idx = findIndex(key);
if(idx < 0)
return null;
if(Util.equals(key, array[idx]))
return new MapEntry(array[idx], array[idx+1]);
return null;
}
public Object find(int shift, int hash, Object key, Object notFound){
int idx = findIndex(key);
if(idx < 0)
return notFound;
if(Util.equals(key, array[idx]))
return array[idx+1];
return notFound;
}
public ISeq nodeSeq(){
return NodeSeq.create(array);
}
public int findIndex(Object key){
for(int i = 0; i < 2*count; i+=2)
{
if(Util.equals(key, array[i]))
return i;
}
return -1;
}
private HashCollisionNode ensureEditable(AtomicReference<Thread> edit){
if(this.edit == edit)
return this;
return new HashCollisionNode(edit, hash, count, array);
}
private HashCollisionNode ensureEditable(AtomicReference<Thread> edit, int count, Object[] array){
if(this.edit == edit) {
this.array = array;
this.count = count;
return this;
}
return new HashCollisionNode(edit, hash, count, array);
}
private HashCollisionNode editAndSet(AtomicReference<Thread> edit, int i, Object a) {
HashCollisionNode editable = ensureEditable(edit);
editable.array[i] = a;
return editable;
}
private HashCollisionNode editAndSet(AtomicReference<Thread> edit, int i, Object a, int j, Object b) {
HashCollisionNode editable = ensureEditable(edit);
editable.array[i] = a;
editable.array[j] = b;
return editable;
}
public INode assoc(AtomicReference<Thread> edit, int shift, int hash, Object key, Object val, Box addedLeaf){
if(hash == this.hash) {
int idx = findIndex(key);
if(idx != -1) {
if(array[idx + 1] == val)
return this;
return editAndSet(edit, idx+1, val);
}
if (array.length > 2*count) {
addedLeaf.val = addedLeaf;
HashCollisionNode editable = editAndSet(edit, 2*count, key, 2*count+1, val);
editable.count++;
return editable;
}
Object[] newArray = new Object[array.length + 2];
System.arraycopy(array, 0, newArray, 0, array.length);
newArray[array.length] = key;
newArray[array.length + 1] = val;
addedLeaf.val = addedLeaf;
return ensureEditable(edit, count + 1, newArray);
}
// nest it in a bitmap node
return new BitmapIndexedNode(edit, bitpos(this.hash, shift), new Object[] {null, this, null, null})
.assoc(edit, shift, hash, key, val, addedLeaf);
}
public INode without(AtomicReference<Thread> edit, int shift, int hash, Object key, Box removedLeaf){
int idx = findIndex(key);
if(idx == -1)
return this;
if(count == 1)
return null;
HashCollisionNode editable = ensureEditable(edit);
editable.array[idx] = editable.array[2*count-2];
editable.array[idx+1] = editable.array[2*count-1];
editable.array[2*count-2] = editable.array[2*count-1] = null;
editable.count--;
return editable;
}
}
/*
public static void main(String[] args){
try
{
ArrayList words = new ArrayList();
Scanner s = new Scanner(new File(args[0]));
s.useDelimiter(Pattern.compile("\\W"));
while(s.hasNext())
{
String word = s.next();
words.add(word);
}
System.out.println("words: " + words.size());
IPersistentMap map = PersistentHashMap.EMPTY;
//IPersistentMap map = new PersistentTreeMap();
//Map ht = new Hashtable();
Map ht = new HashMap();
Random rand;
System.out.println("Building map");
long startTime = System.nanoTime();
for(Object word5 : words)
{
map = map.assoc(word5, word5);
}
rand = new Random(42);
IPersistentMap snapshotMap = map;
for(int i = 0; i < words.size() / 200; i++)
{
map = map.without(words.get(rand.nextInt(words.size() / 2)));
}
long estimatedTime = System.nanoTime() - startTime;
System.out.println("count = " + map.count() + ", time: " + estimatedTime / 1000000);
System.out.println("Building ht");
startTime = System.nanoTime();
for(Object word1 : words)
{
ht.put(word1, word1);
}
rand = new Random(42);
for(int i = 0; i < words.size() / 200; i++)
{
ht.remove(words.get(rand.nextInt(words.size() / 2)));
}
estimatedTime = System.nanoTime() - startTime;
System.out.println("count = " + ht.size() + ", time: " + estimatedTime / 1000000);
System.out.println("map lookup");
startTime = System.nanoTime();
int c = 0;
for(Object word2 : words)
{
if(!map.contains(word2))
++c;
}
estimatedTime = System.nanoTime() - startTime;
System.out.println("notfound = " + c + ", time: " + estimatedTime / 1000000);
System.out.println("ht lookup");
startTime = System.nanoTime();
c = 0;
for(Object word3 : words)
{
if(!ht.containsKey(word3))
++c;
}
estimatedTime = System.nanoTime() - startTime;
System.out.println("notfound = " + c + ", time: " + estimatedTime / 1000000);
System.out.println("snapshotMap lookup");
startTime = System.nanoTime();
c = 0;
for(Object word4 : words)
{
if(!snapshotMap.contains(word4))
++c;
}
estimatedTime = System.nanoTime() - startTime;
System.out.println("notfound = " + c + ", time: " + estimatedTime / 1000000);
}
catch(FileNotFoundException e)
{
e.printStackTrace();
}
}
*/
private static INode[] cloneAndSet(INode[] array, int i, INode a) {
INode[] clone = array.clone();
clone[i] = a;
return clone;
}
private static Object[] cloneAndSet(Object[] array, int i, Object a) {
Object[] clone = array.clone();
clone[i] = a;
return clone;
}
private static Object[] cloneAndSet(Object[] array, int i, Object a, int j, Object b) {
Object[] clone = array.clone();
clone[i] = a;
clone[j] = b;
return clone;
}
private static Object[] removePair(Object[] array, int i) {
Object[] newArray = new Object[array.length - 2];
System.arraycopy(array, 0, newArray, 0, 2*i);
System.arraycopy(array, 2*(i+1), newArray, 2*i, newArray.length - 2*i);
return newArray;
}
private static INode createNode(int shift, Object key1, Object val1, int key2hash, Object key2, Object val2) {
int key1hash = Util.hash(key1);
if(key1hash == key2hash)
return new HashCollisionNode(null, key1hash, 2, new Object[] {key1, val1, key2, val2});
Box _ = new Box(null);
AtomicReference<Thread> edit = new AtomicReference<Thread>();
return BitmapIndexedNode.EMPTY
.assoc(edit, shift, key1hash, key1, val1, _)
.assoc(edit, shift, key2hash, key2, val2, _);
}
private static INode createNode(AtomicReference<Thread> edit, int shift, Object key1, Object val1, int key2hash, Object key2, Object val2) {
int key1hash = Util.hash(key1);
if(key1hash == key2hash)
return new HashCollisionNode(null, key1hash, 2, new Object[] {key1, val1, key2, val2});
Box _ = new Box(null);
return BitmapIndexedNode.EMPTY
.assoc(edit, shift, key1hash, key1, val1, _)
.assoc(edit, shift, key2hash, key2, val2, _);
}
private static int bitpos(int hash, int shift){
return 1 << mask(hash, shift);
}
static final class NodeSeq extends ASeq {
final Object[] array;
final int i;
final ISeq s;
NodeSeq(Object[] array, int i) {
this(null, array, i, null);
}
static ISeq create(Object[] array) {
return create(array, 0, null);
}
private static ISeq create(Object[] array, int i, ISeq s) {
if(s != null)
return new NodeSeq(null, array, i, s);
for(int j = i; j < array.length; j+=2) {
if(array[j] != null)
return new NodeSeq(null, array, j, null);
INode node = (INode) array[j+1];
if (node != null) {
ISeq nodeSeq = node.nodeSeq();
if(nodeSeq != null)
return new NodeSeq(null, array, j + 2, nodeSeq);
}
}
return null;
}
NodeSeq(IPersistentMap meta, Object[] array, int i, ISeq s) {
super(meta);
this.array = array;
this.i = i;
this.s = s;
}
public Obj withMeta(IPersistentMap meta) {
return new NodeSeq(meta, array, i, s);
}
public Object first() {
if(s != null)
return s.first();
return new MapEntry(array[i], array[i+1]);
}
public ISeq next() {
if(s != null)
return create(array, i, s.next());
return create(array, i + 2, null);
}
}
}