/*
* Copyright 2000-2014 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.intellij.util.containers;
import com.intellij.util.concurrency.AtomicFieldUpdater;
import org.jetbrains.annotations.NotNull;
import sun.misc.Unsafe;
import java.util.*;
import java.util.concurrent.locks.LockSupport;
/**
* Adapted from java.util.concurrent.ConcurrentHashMap to int keys
* @author Doug Lea
* @param <V> the type of mapped values
* @deprecated Use {@link ContainerUtil#createConcurrentIntObjectMap()} instead
*/
// added hashing strategy argument
// added cacheOrGet convenience method
// Null values are NOT allowed
class ConcurrentIntObjectHashMap<V> implements ConcurrentIntObjectMap<V> {
/**
* The largest possible table capacity. This value must be
* exactly 1<<30 to stay within Java array allocation and indexing
* bounds for power of two table sizes, and is further required
* because the top two bits of 32bit hash fields are used for
* control purposes.
*/
private static final int MAXIMUM_CAPACITY = 1 << 30;
/**
* The default initial table capacity. Must be a power of 2
* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
*/
private static final int DEFAULT_CAPACITY = 16;
/**
* The largest possible (non-power of two) array size.
* Needed by toArray and related methods.
*/
static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* The bin count threshold for using a tree rather than list for a
* bin. Bins are converted to trees when adding an element to a
* bin with at least this many nodes. The value must be greater
* than 2, and should be at least 8 to mesh with assumptions in
* tree removal about conversion back to plain bins upon
* shrinkage.
*/
static final int TREEIFY_THRESHOLD = 8;
/**
* The bin count threshold for untreeifying a (split) bin during a
* resize operation. Should be less than TREEIFY_THRESHOLD, and at
* most 6 to mesh with shrinkage detection under removal.
*/
static final int UNTREEIFY_THRESHOLD = 6;
/**
* The smallest table capacity for which bins may be treeified.
* (Otherwise the table is resized if too many nodes in a bin.)
* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
* conflicts between resizing and treeification thresholds.
*/
static final int MIN_TREEIFY_CAPACITY = 64;
/**
* Minimum number of rebinnings per transfer step. Ranges are
* subdivided to allow multiple resizer threads. This value
* serves as a lower bound to avoid resizers encountering
* excessive memory contention. The value should be at least
* DEFAULT_CAPACITY.
*/
private static final int MIN_TRANSFER_STRIDE = 16;
/**
* The number of bits used for generation stamp in sizeCtl.
* Must be at least 6 for 32bit arrays.
*/
private static final int RESIZE_STAMP_BITS = 16;
/**
* The maximum number of threads that can help resize.
* Must fit in 32 - RESIZE_STAMP_BITS bits.
*/
private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
/**
* The bit shift for recording size stamp in sizeCtl.
*/
private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
/*
* Encodings for Node hash fields. See above for explanation.
*/
static final int MOVED = -1; // hash for forwarding nodes
static final int TREEBIN = -2; // hash for roots of trees
static final int RESERVED = -3; // hash for transient reservations
static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
/**
* Number of CPUS, to place bounds on some sizings
*/
static final int NCPU = Runtime.getRuntime().availableProcessors();
/* ---------------- Nodes -------------- */
/**
* Key-value entry. This class is never exported out as a
* user-mutable Map.Entry (i.e., one supporting setValue; see
* MapEntry below), but can be used for read-only traversals used
* in bulk tasks. Subclasses of Node with a negative hash field
* are special, and contain null keys and values (but are never
* exported). Otherwise, keys and vals are never null.
*/
static class Node<V> implements IntEntry<V> {
final int hash;
final int key;
volatile V val;
volatile Node<V> next;
Node(int hash, int key, V val, Node<V> next) {
this.hash = hash;
this.key = key;
this.val = val;
this.next = next;
}
@Override
public final int getKey() {
return key;
}
@NotNull
@Override
public final V getValue() {
return val;
}
@Override
public final int hashCode() {
return (int)(key ^ val.hashCode());
}
@Override
public final String toString() {
return key + "=" + val;
}
@Override
public final boolean equals(Object o) {
Object v;
Object u;
IntEntry<?> e;
return ((o instanceof IntEntry) &&
(e = (IntEntry<?>)o).getKey() == key &&
(v = e.getValue()) != null &&
(v == (u = val) || v.equals(u)));
}
/**
* Virtualized support for map.get(); overridden in subclasses.
*/
Node<V> find(int h, int k) {
Node<V> e = this;
do {
if ((e.key == k)) {
return e;
}
}
while ((e = e.next) != null);
return null;
}
}
/* ---------------- Static utilities -------------- */
/**
* Spreads (XORs) higher bits of hash to lower and also forces top
* bit to 0. Because the table uses power-of-two masking, sets of
* hashes that vary only in bits above the current mask will
* always collide. (Among known examples are sets of Float keys
* holding consecutive whole numbers in small tables.) So we
* apply a transform that spreads the impact of higher bits
* downward. There is a tradeoff between speed, utility, and
* quality of bit-spreading. Because many common sets of hashes
* are already reasonably distributed (so don't benefit from
* spreading), and because we use trees to handle large sets of
* collisions in bins, we just XOR some shifted bits in the
* cheapest possible way to reduce systematic lossage, as well as
* to incorporate impact of the highest bits that would otherwise
* never be used in index calculations because of table bounds.
*/
static int spread(int h) {
return (int)((h ^ (h >>> 16)) & HASH_BITS);
}
/**
* Returns a power of two table size for the given desired capacity.
* See Hackers Delight, sec 3.2
*/
private static int tableSizeFor(int c) {
int n = c - 1;
n |= n >>> 1;
n |= n >>> 2;
n |= n >>> 4;
n |= n >>> 8;
n |= n >>> 16;
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
}
/* ---------------- Table element access -------------- */
/*
* Volatile access methods are used for table elements as well as
* elements of in-progress next table while resizing. All uses of
* the tab arguments must be null checked by callers. All callers
* also paranoically precheck that tab's length is not zero (or an
* equivalent check), thus ensuring that any index argument taking
* the form of a hash value anded with (length - 1) is a valid
* index. Note that, to be correct wrt arbitrary concurrency
* errors by users, these checks must operate on local variables,
* which accounts for some odd-looking inline assignments below.
* Note that calls to setTabAt always occur within locked regions,
* and so in principle require only release ordering, not
* full volatile semantics, but are currently coded as volatile
* writes to be conservative.
*/
@SuppressWarnings("unchecked")
static <V> Node<V> tabAt(Node<V>[] tab, int i) {
return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
}
static <V> boolean casTabAt(Node<V>[] tab, int i,
Node<V> c, Node<V> v) {
return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
}
static <V> void setTabAt(Node<V>[] tab, int i, Node<V> v) {
U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
}
/* ---------------- Fields -------------- */
/**
* The array of bins. Lazily initialized upon first insertion.
* Size is always a power of two. Accessed directly by iterators.
*/
transient volatile Node<V>[] table;
/**
* The next table to use; non-null only while resizing.
*/
private transient volatile Node<V>[] nextTable;
/**
* Base counter value, used mainly when there is no contention,
* but also as a fallback during table initialization
* races. Updated via CAS.
*/
@SuppressWarnings("UnusedDeclaration")
private transient volatile long baseCount;
/**
* Table initialization and resizing control. When negative, the
* table is being initialized or resized: -1 for initialization,
* else -(1 + the number of active resizing threads). Otherwise,
* when table is null, holds the initial table size to use upon
* creation, or 0 for default. After initialization, holds the
* next element count value upon which to resize the table.
*/
private transient volatile int sizeCtl;
/**
* The next table index (plus one) to split while resizing.
*/
private transient volatile int transferIndex;
/**
* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
*/
private transient volatile int cellsBusy;
/**
* Table of counter cells. When non-null, size is a power of 2.
*/
private transient volatile ConcurrentHashMap.CounterCell[] counterCells;
// views
private transient ValuesView<V> values;
private transient EntrySetView<V> entrySet;
/* ---------------- Public operations -------------- */
/**
* Creates a new, empty map with the default initial table size (16).
*/
public ConcurrentIntObjectHashMap() {
}
/**
* Creates a new, empty map with an initial table size
* accommodating the specified number of elements without the need
* to dynamically resize.
*
* @param initialCapacity The implementation performs internal
* sizing to accommodate this many elements.
* @throws IllegalArgumentException if the initial capacity of
* elements is negative
*/
public ConcurrentIntObjectHashMap(int initialCapacity) {
if (initialCapacity < 0) {
throw new IllegalArgumentException();
}
int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
MAXIMUM_CAPACITY :
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
sizeCtl = cap;
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}) and
* initial table density ({@code loadFactor}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @throws IllegalArgumentException if the initial capacity of
* elements is negative or the load factor is nonpositive
* @since 1.6
*/
public ConcurrentIntObjectHashMap(int initialCapacity, float loadFactor) {
this(initialCapacity, loadFactor, 1);
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}), table
* density ({@code loadFactor}), and number of concurrently
* updating threads ({@code concurrencyLevel}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @param concurrencyLevel the estimated number of concurrently
* updating threads. The implementation may use this value as
* a sizing hint.
* @throws IllegalArgumentException if the initial capacity is
* negative or the load factor or concurrencyLevel are
* nonpositive
*/
public ConcurrentIntObjectHashMap(int initialCapacity,
float loadFactor, int concurrencyLevel) {
if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) {
throw new IllegalArgumentException();
}
if (initialCapacity < concurrencyLevel) // Use at least as many bins
{
initialCapacity = concurrencyLevel; // as estimated threads
}
long size = (long)(1.0 + (long)initialCapacity / loadFactor);
int cap = (size >= (long)MAXIMUM_CAPACITY) ?
MAXIMUM_CAPACITY : tableSizeFor((int)size);
sizeCtl = cap;
}
// Original (since JDK1.2) Map methods
/**
* {@inheritDoc}
*/
@Override
public int size() {
long n = sumCount();
return ((n < 0L) ? 0 :
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
(int)n);
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEmpty() {
return sumCount() <= 0L; // ignore transient negative values
}
/**
* Returns the value to which the specified key is mapped,
* or {@code null} if this map contains no mapping for the key.
* <p/>
* <p>More formally, if this map contains a mapping from a key
* {@code k} to a value {@code v} such that {@code key.equals(k)},
* then this method returns {@code v}; otherwise it returns
* {@code null}. (There can be at most one such mapping.)
*/
@Override
public V get(int key) {
Node<V>[] tab;
Node<V> e;
Node<V> p;
int n, eh;
int h = spread(key);
if ((tab = table) != null && (n = tab.length) > 0 &&
(e = tabAt(tab, (n - 1) & h)) != null) {
if ((eh = e.hash) == h) {
if (e.key == key) {
return e.val;
}
}
else if (eh < 0) {
return (p = e.find(h, key)) != null ? p.val : null;
}
while ((e = e.next) != null) {
if (e.hash == h &&
(e.key == key)) {
return e.val;
}
}
}
return null;
}
/**
* Tests if the specified object is a key in this table.
*
* @param key possible key
* @return {@code true} if and only if the specified object
* is a key in this table, as determined by the
* {@code equals} method; {@code false} otherwise
*/
@Override
public boolean containsKey(int key) {
return get(key) != null;
}
/**
* Returns {@code true} if this map maps one or more keys to the
* specified value. Note: This method may require a full traversal
* of the map, and is much slower than method {@code containsKey}.
*
* @param value value whose presence in this map is to be tested
* @return {@code true} if this map maps one or more keys to the
* specified value
*/
@Override
public boolean containsValue(@NotNull Object value) {
Node<V>[] t;
if ((t = table) != null) {
Traverser<V> it = new Traverser<V>(t, t.length, 0, t.length);
for (Node<V> p; (p = it.advance()) != null; ) {
V v;
if ((v = p.val) == value || (v != null && value.equals(v))) {
return true;
}
}
}
return false;
}
/**
* Maps the specified key to the specified value in this table.
* Neither the key nor the value can be null.
* <p/>
* <p>The value can be retrieved by calling the {@code get} method
* with a key that is equal to the original key.
*
* @param key key with which the specified value is to be associated
* @param value value to be associated with the specified key
* @return the previous value associated with {@code key}, or
* {@code null} if there was no mapping for {@code key}
*/
@Override
public V put(int key, @NotNull V value) {
return putVal(key, value, false);
}
/**
* Implementation for put and putIfAbsent
*/
final V putVal(int key, @NotNull V value, boolean onlyIfAbsent) {
int hash = spread(key);
int binCount = 0;
for (Node<V>[] tab = table; ; ) {
Node<V> f;
int n, i, fh;
if (tab == null || (n = tab.length) == 0) {
tab = initTable();
}
else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
if (casTabAt(tab, i, null,
new Node<V>(hash, key, value, null))) {
break; // no lock when adding to empty bin
}
}
else if ((fh = f.hash) == MOVED) {
tab = helpTransfer(tab, f);
}
else {
V oldVal = null;
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node<V> e = f; ; ++binCount) {
if ((e.key == key)) {
oldVal = e.val;
if (!onlyIfAbsent) {
e.val = value;
}
break;
}
Node<V> pred = e;
if ((e = e.next) == null) {
pred.next = new Node<V>(hash, key,
value, null);
break;
}
}
}
else if (f instanceof TreeBin) {
Node<V> p;
binCount = 2;
if ((p = ((TreeBin<V>)f).putTreeVal(hash, key,
value)) != null) {
oldVal = p.val;
if (!onlyIfAbsent) {
p.val = value;
}
}
}
}
}
if (binCount != 0) {
if (binCount >= TREEIFY_THRESHOLD) {
treeifyBin(tab, i);
}
if (oldVal != null) {
return oldVal;
}
break;
}
}
}
addCount(1L, binCount);
return null;
}
/**
* Removes the key (and its corresponding value) from this map.
* This method does nothing if the key is not in the map.
*
* @param key the key that needs to be removed
* @return the previous value associated with {@code key}, or
* {@code null} if there was no mapping for {@code key}
*/
@Override
public V remove(int key) {
return replaceNode(key, null, null);
}
/**
* Implementation for the four public remove/replace methods:
* Replaces node value with v, conditional upon match of cv if
* non-null. If resulting value is null, delete.
*/
final V replaceNode(int key, V value, Object cv) {
int hash = spread(key);
for (Node<V>[] tab = table; ; ) {
Node<V> f;
int n, i, fh;
if (tab == null || (n = tab.length) == 0 ||
(f = tabAt(tab, i = (n - 1) & hash)) == null) {
break;
}
else if ((fh = f.hash) == MOVED) {
tab = helpTransfer(tab, f);
}
else {
V oldVal = null;
boolean validated = false;
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
validated = true;
for (Node<V> e = f, pred = null; ; ) {
if ((e.key == key)) {
V ev = e.val;
if (cv == null || cv == ev ||
(ev != null && cv.equals(ev))) {
oldVal = ev;
if (value != null) {
e.val = value;
}
else if (pred != null) {
pred.next = e.next;
}
else {
setTabAt(tab, i, e.next);
}
}
break;
}
pred = e;
if ((e = e.next) == null) {
break;
}
}
}
else if (f instanceof TreeBin) {
validated = true;
TreeBin<V> t = (TreeBin<V>)f;
TreeNode<V> r, p;
if ((r = t.root) != null &&
(p = r.findTreeNode(hash, key)) != null) {
V pv = p.val;
if (cv == null || cv == pv ||
(pv != null && cv.equals(pv))) {
oldVal = pv;
if (value != null) {
p.val = value;
}
else if (t.removeTreeNode(p)) {
setTabAt(tab, i, untreeify(t.first));
}
}
}
}
}
}
if (validated) {
if (oldVal != null) {
if (value == null) {
addCount(-1L, -1);
}
return oldVal;
}
break;
}
}
}
return null;
}
/**
* Removes all of the mappings from this map.
*/
@Override
public void clear() {
long delta = 0L; // negative number of deletions
int i = 0;
Node<V>[] tab = table;
while (tab != null && i < tab.length) {
int fh;
Node<V> f = tabAt(tab, i);
if (f == null) {
++i;
}
else if ((fh = f.hash) == MOVED) {
tab = helpTransfer(tab, f);
i = 0; // restart
}
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
Node<V> p = (fh >= 0 ? f :
(f instanceof TreeBin) ?
((TreeBin<V>)f).first : null);
while (p != null) {
--delta;
p = p.next;
}
setTabAt(tab, i++, null);
}
}
}
}
if (delta != 0L) {
addCount(delta, -1);
}
}
/**
* Returns a {@link Collection} view of the values contained in this map.
* The collection is backed by the map, so changes to the map are
* reflected in the collection, and vice-versa. The collection
* supports element removal, which removes the corresponding
* mapping from this map, via the {@code Iterator.remove},
* {@code Collection.remove}, {@code removeAll},
* {@code retainAll}, and {@code clear} operations. It does not
* support the {@code add} or {@code addAll} operations.
* <p/>
* <p>The view's iterators and spliterators are
* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
* <p/>
*
* @return the collection view
*/
@NotNull
@Override
public Collection<V> values() {
ValuesView<V> vs;
return (vs = values) != null ? vs : (values = new ValuesView<V>(this));
}
/**
* Returns a {@link Set} view of the mappings contained in this map.
* The set is backed by the map, so changes to the map are
* reflected in the set, and vice-versa. The set supports element
* removal, which removes the corresponding mapping from the map,
* via the {@code Iterator.remove}, {@code Set.remove},
* {@code removeAll}, {@code retainAll}, and {@code clear}
* operations.
* <p/>
* <p>The view's iterators and spliterators are
* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
* <p/>
*
* @return the set view
*/
public Set<IntEntry<V>> entrySet() {
EntrySetView<V> es;
return (es = entrySet) != null ? es : (entrySet = new EntrySetView<V>(this));
}
/**
* Returns the hash code value for this {@link Map}, i.e.,
* the sum of, for each key-value pair in the map,
* {@code key.hashCode() ^ value.hashCode()}.
*
* @return the hash code value for this map
*/
@Override
public int hashCode() {
int h = 0;
Node<V>[] t;
if ((t = table) != null) {
Traverser<V> it = new Traverser<V>(t, t.length, 0, t.length);
for (Node<V> p; (p = it.advance()) != null; ) {
h += p.key ^ p.val.hashCode();
}
}
return h;
}
/**
* Returns a string representation of this map. The string
* representation consists of a list of key-value mappings (in no
* particular order) enclosed in braces ("{@code {}}"). Adjacent
* mappings are separated by the characters {@code ", "} (comma
* and space). Each key-value mapping is rendered as the key
* followed by an equals sign ("{@code =}") followed by the
* associated value.
*
* @return a string representation of this map
*/
@Override
public String toString() {
Node<V>[] t;
int f = (t = table) == null ? 0 : t.length;
Traverser<V> it = new Traverser<V>(t, f, 0, f);
StringBuilder sb = new StringBuilder();
sb.append('{');
Node<V> p;
if ((p = it.advance()) != null) {
for (; ; ) {
int k = p.key;
V v = p.val;
sb.append(k);
sb.append('=');
sb.append(v == this ? "(this Map)" : v);
if ((p = it.advance()) == null) {
break;
}
sb.append(',').append(' ');
}
}
return sb.append('}').toString();
}
/**
* Compares the specified object with this map for equality.
* Returns {@code true} if the given object is a map with the same
* mappings as this map. This operation may return misleading
* results if either map is concurrently modified during execution
* of this method.
*
* @param o object to be compared for equality with this map
* @return {@code true} if the specified object is equal to this map
*/
@Override
public boolean equals(Object o) {
if (o != this) {
if (!(o instanceof ConcurrentIntObjectMap)) {
return false;
}
ConcurrentIntObjectMap<?> m = (ConcurrentIntObjectMap)o;
Node<V>[] t;
int f = (t = table) == null ? 0 : t.length;
Traverser<V> it = new Traverser<V>(t, f, 0, f);
for (Node<V> p; (p = it.advance()) != null; ) {
V val = p.val;
Object v = m.get(p.key);
if (v == null || (v != val && !v.equals(val))) {
return false;
}
}
for (IntEntry e : m.entries()) {
int mk = e.getKey();
Object mv;
Object v;
if ((mv = e.getValue()) == null || (v = get(mk)) == null || (mv != v && !mv.equals(v))) {
return false;
}
}
}
return true;
}
// ConcurrentMap methods
/**
* {@inheritDoc}
*
* @return the previous value associated with the specified key,
* or {@code null} if there was no mapping for the key
*/
@Override
public V putIfAbsent(int key, @NotNull V value) {
return putVal(key, value, true);
}
/**
* {@inheritDoc}
*/
@Override
public boolean remove(int key, @NotNull Object value) {
return replaceNode(key, null, value) != null;
}
/**
* {@inheritDoc}
*/
@Override
public boolean replace(int key, @NotNull V oldValue, @NotNull V newValue) {
return replaceNode(key, newValue, oldValue) != null;
}
/**
* {@inheritDoc}
*
* @return the previous value associated with the specified key,
* or {@code null} if there was no mapping for the key
*/
public V replace(int key, @NotNull V value) {
return replaceNode(key, value, null);
}
// Overrides of JDK8+ Map extension method defaults
/**
* Returns the value to which the specified key is mapped, or the
* given default value if this map contains no mapping for the
* key.
*
* @param key the key whose associated value is to be returned
* @param defaultValue the value to return if this map contains
* no mapping for the given key
* @return the mapping for the key, if present; else the default value
*/
public V getOrDefault(int key, V defaultValue) {
V v;
return (v = get(key)) == null ? defaultValue : v;
}
// Hashtable legacy methods
/**
* Legacy method testing if some key maps into the specified value
* in this table. This method is identical in functionality to
* {@link #containsValue(Object)}, and exists solely to ensure
* full compatibility with class {@link java.util.Hashtable},
* which supported this method prior to introduction of the
* Java Collections framework.
*
* @param value a value to search for
* @return {@code true} if and only if some key maps to the
* {@code value} argument in this table as
* determined by the {@code equals} method;
* {@code false} otherwise
*/
public boolean contains(Object value) {
return containsValue(value);
}
/**
* Returns an enumeration of the keys in this table.
*
* @return an enumeration of the keys in this table
*/
@NotNull
@Override
public int[] keys() {
Object[] entries = new EntrySetView<V>(this).toArray();
int[] result = new int[entries.length];
for (int i = 0; i < entries.length; i++) {
IntEntry<V> entry = (IntEntry<V>)entries[i];
result[i] = entry.getKey();
}
return result;
}
/**
* Returns an enumeration of the values in this table.
*
* @return an enumeration of the values in this table
* @see #values()
*/
@NotNull
@Override
public Enumeration<V> elements() {
Node<V>[] t;
int f = (t = table) == null ? 0 : t.length;
return new ValueIterator<V>(t, f, 0, f, this);
}
// ConcurrentHashMap-only methods
/**
* Returns the number of mappings. This method should be used
* instead of {@link #size} because a ConcurrentHashMap may
* contain more mappings than can be represented as an int. The
* value returned is an estimate; the actual count may differ if
* there are concurrent insertions or removals.
*
* @return the number of mappings
* @since 1.8
*/
public long mappingCount() {
long n = sumCount();
return (n < 0L) ? 0L : n; // ignore transient negative values
}
/* ---------------- Special Nodes -------------- */
/**
* A node inserted at head of bins during transfer operations.
*/
static final class ForwardingNode<V> extends Node<V> {
final Node<V>[] nextTable;
ForwardingNode(Node<V>[] tab) {
super(MOVED, 0, null, null);
nextTable = tab;
}
@Override
Node<V> find(int h, int k) {
// loop to avoid arbitrarily deep recursion on forwarding nodes
outer:
for (Node<V>[] tab = nextTable; ; ) {
Node<V> e;
int n;
if (tab == null || (n = tab.length) == 0 ||
(e = tabAt(tab, (n - 1) & h)) == null) {
return null;
}
for (; ; ) {
if ((e.key == k)) {
return e;
}
if (e.hash < 0) {
if (e instanceof ForwardingNode) {
tab = ((ForwardingNode<V>)e).nextTable;
continue outer;
}
else {
return e.find(h, k);
}
}
if ((e = e.next) == null) {
return null;
}
}
}
}
}
/* ---------------- Table Initialization and Resizing -------------- */
/**
* Returns the stamp bits for resizing a table of size n.
* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
*/
static int resizeStamp(int n) {
return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
}
/**
* Initializes table, using the size recorded in sizeCtl.
*/
private Node<V>[] initTable() {
Node<V>[] tab;
int sc;
while ((tab = table) == null || tab.length == 0) {
if ((sc = sizeCtl) < 0) {
Thread.yield(); // lost initialization race; just spin
}
else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if ((tab = table) == null || tab.length == 0) {
int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
@SuppressWarnings("unchecked")
Node<V>[] nt = (Node<V>[])new Node<?>[n];
table = tab = nt;
sc = n - (n >>> 2);
}
}
finally {
sizeCtl = sc;
}
break;
}
}
return tab;
}
/**
* Adds to count, and if table is too small and not already
* resizing, initiates transfer. If already resizing, helps
* perform transfer if work is available. Rechecks occupancy
* after a transfer to see if another resize is already needed
* because resizings are lagging additions.
*
* @param x the count to add
* @param check if <0, don't check resize, if <= 1 only check if uncontended
*/
private void addCount(long x, int check) {
ConcurrentHashMap.CounterCell[] as;
long b, s;
if ((as = counterCells) != null ||
!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
ConcurrentHashMap.CounterCell a;
long v;
int m;
boolean uncontended = true;
if (as == null || (m = as.length - 1) < 0 ||
(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
!(uncontended =
U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
fullAddCount(x, uncontended);
return;
}
if (check <= 1) {
return;
}
s = sumCount();
}
if (check >= 0) {
Node<V>[] tab, nt;
int n, sc;
while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
(n = tab.length) < MAXIMUM_CAPACITY) {
int rs = resizeStamp(n);
if (sc < 0) {
if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
transferIndex <= 0) {
break;
}
if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
transfer(tab, nt);
}
}
else if (U.compareAndSwapInt(this, SIZECTL, sc,
(rs << RESIZE_STAMP_SHIFT) + 2)) {
transfer(tab, null);
}
s = sumCount();
}
}
}
/**
* Helps transfer if a resize is in progress.
*/
final Node<V>[] helpTransfer(Node<V>[] tab, Node<V> f) {
Node<V>[] nextTab;
int sc;
if (tab != null && (f instanceof ForwardingNode) &&
(nextTab = ((ForwardingNode<V>)f).nextTable) != null) {
int rs = resizeStamp(tab.length);
while (nextTab == nextTable && table == tab &&
(sc = sizeCtl) < 0) {
if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
sc == rs + MAX_RESIZERS || transferIndex <= 0) {
break;
}
if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
transfer(tab, nextTab);
break;
}
}
return nextTab;
}
return table;
}
/**
* Tries to presize table to accommodate the given number of elements.
*
* @param size number of elements (doesn't need to be perfectly accurate)
*/
private void tryPresize(int size) {
int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
tableSizeFor(size + (size >>> 1) + 1);
int sc;
while ((sc = sizeCtl) >= 0) {
Node<V>[] tab = table;
int n;
if (tab == null || (n = tab.length) == 0) {
n = (sc > c) ? sc : c;
if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if (table == tab) {
@SuppressWarnings("unchecked")
Node<V>[] nt = (Node<V>[])new Node<?>[n];
table = nt;
sc = n - (n >>> 2);
}
}
finally {
sizeCtl = sc;
}
}
}
else if (c <= sc || n >= MAXIMUM_CAPACITY) {
break;
}
else if (tab == table) {
int rs = resizeStamp(n);
if (sc < 0) {
Node<V>[] nt;
if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
transferIndex <= 0) {
break;
}
if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
transfer(tab, nt);
}
}
else if (U.compareAndSwapInt(this, SIZECTL, sc,
(rs << RESIZE_STAMP_SHIFT) + 2)) {
transfer(tab, null);
}
}
}
}
/**
* Moves and/or copies the nodes in each bin to new table. See
* above for explanation.
*/
private void transfer(Node<V>[] tab, Node<V>[] nextTab) {
int n = tab.length, stride;
if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) {
stride = MIN_TRANSFER_STRIDE; // subdivide range
}
if (nextTab == null) { // initiating
try {
@SuppressWarnings("unchecked")
Node<V>[] nt = (Node<V>[])new Node<?>[n << 1];
nextTab = nt;
}
catch (Throwable ex) { // try to cope with OOME
sizeCtl = Integer.MAX_VALUE;
return;
}
nextTable = nextTab;
transferIndex = n;
}
int nextn = nextTab.length;
ForwardingNode<V> fwd = new ForwardingNode<V>(nextTab);
boolean advance = true;
boolean finishing = false; // to ensure sweep before committing nextTab
for (int i = 0, bound = 0; ; ) {
Node<V> f;
int fh;
while (advance) {
int nextIndex, nextBound;
if (--i >= bound || finishing) {
advance = false;
}
else if ((nextIndex = transferIndex) <= 0) {
i = -1;
advance = false;
}
else if (U.compareAndSwapInt
(this, TRANSFERINDEX, nextIndex,
nextBound = (nextIndex > stride ?
nextIndex - stride : 0))) {
bound = nextBound;
i = nextIndex - 1;
advance = false;
}
}
if (i < 0 || i >= n || i + n >= nextn) {
int sc;
if (finishing) {
nextTable = null;
table = nextTab;
sizeCtl = (n << 1) - (n >>> 1);
return;
}
if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT) {
return;
}
finishing = advance = true;
i = n; // recheck before commit
}
}
else if ((f = tabAt(tab, i)) == null) {
advance = casTabAt(tab, i, null, fwd);
}
else if ((fh = f.hash) == MOVED) {
advance = true; // already processed
}
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
Node<V> ln, hn;
if (fh >= 0) {
int runBit = fh & n;
Node<V> lastRun = f;
for (Node<V> p = f.next; p != null; p = p.next) {
int b = p.hash & n;
if (b != runBit) {
runBit = b;
lastRun = p;
}
}
if (runBit == 0) {
ln = lastRun;
hn = null;
}
else {
hn = lastRun;
ln = null;
}
for (Node<V> p = f; p != lastRun; p = p.next) {
int ph = p.hash;
int pk = p.key;
V pv = p.val;
if ((ph & n) == 0) {
ln = new Node<V>(ph, pk, pv, ln);
}
else {
hn = new Node<V>(ph, pk, pv, hn);
}
}
setTabAt(nextTab, i, ln);
setTabAt(nextTab, i + n, hn);
setTabAt(tab, i, fwd);
advance = true;
}
else if (f instanceof TreeBin) {
TreeBin<V> t = (TreeBin<V>)f;
TreeNode<V> lo = null, loTail = null;
TreeNode<V> hi = null, hiTail = null;
int lc = 0, hc = 0;
for (Node<V> e = t.first; e != null; e = e.next) {
int h = e.hash;
TreeNode<V> p = new TreeNode<V>
(h, e.key, e.val, null, null);
if ((h & n) == 0) {
if ((p.prev = loTail) == null) {
lo = p;
}
else {
loTail.next = p;
}
loTail = p;
++lc;
}
else {
if ((p.prev = hiTail) == null) {
hi = p;
}
else {
hiTail.next = p;
}
hiTail = p;
++hc;
}
}
ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
(hc != 0) ? new TreeBin<V>(lo) : t;
hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
(lc != 0) ? new TreeBin<V>(hi) : t;
setTabAt(nextTab, i, ln);
setTabAt(nextTab, i + n, hn);
setTabAt(tab, i, fwd);
advance = true;
}
}
}
}
}
}
/* ---------------- Counter support -------------- */
final long sumCount() {
ConcurrentHashMap.CounterCell[] as = counterCells;
ConcurrentHashMap.CounterCell a;
long sum = baseCount;
if (as != null) {
for (int i = 0; i < as.length; ++i) {
if ((a = as[i]) != null) {
sum += a.value;
}
}
}
return sum;
}
// See LongAdder version for explanation
private void fullAddCount(long x, boolean wasUncontended) {
int h;
if ((h = ThreadLocalRandom.getProbe()) == 0) {
ThreadLocalRandom.localInit(); // force initialization
h = ThreadLocalRandom.getProbe();
wasUncontended = true;
}
boolean collide = false; // True if last slot nonempty
for (; ; ) {
ConcurrentHashMap.CounterCell[] as;
ConcurrentHashMap.CounterCell a;
int n;
long v;
if ((as = counterCells) != null && (n = as.length) > 0) {
if ((a = as[(n - 1) & h]) == null) {
if (cellsBusy == 0) { // Try to attach new Cell
ConcurrentHashMap.CounterCell r = new ConcurrentHashMap.CounterCell(x); // Optimistic create
if (cellsBusy == 0 &&
U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
boolean created = false;
try { // Recheck under lock
ConcurrentHashMap.CounterCell[] rs;
int m, j;
if ((rs = counterCells) != null &&
(m = rs.length) > 0 &&
rs[j = (m - 1) & h] == null) {
rs[j] = r;
created = true;
}
}
finally {
cellsBusy = 0;
}
if (created) {
break;
}
continue; // Slot is now non-empty
}
}
collide = false;
}
else if (!wasUncontended) // CAS already known to fail
{
wasUncontended = true; // Continue after rehash
}
else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) {
break;
}
else if (counterCells != as || n >= NCPU) {
collide = false; // At max size or stale
}
else if (!collide) {
collide = true;
}
else if (cellsBusy == 0 &&
U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
try {
if (counterCells == as) {// Expand table unless stale
ConcurrentHashMap.CounterCell[] rs = new ConcurrentHashMap.CounterCell[n << 1];
for (int i = 0; i < n; ++i) {
rs[i] = as[i];
}
counterCells = rs;
}
}
finally {
cellsBusy = 0;
}
collide = false;
continue; // Retry with expanded table
}
h = ThreadLocalRandom.advanceProbe(h);
}
else if (cellsBusy == 0 && counterCells == as &&
U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
boolean init = false;
try { // Initialize table
if (counterCells == as) {
ConcurrentHashMap.CounterCell[] rs = new ConcurrentHashMap.CounterCell[2];
rs[h & 1] = new ConcurrentHashMap.CounterCell(x);
counterCells = rs;
init = true;
}
}
finally {
cellsBusy = 0;
}
if (init) {
break;
}
}
else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) {
break; // Fall back on using base
}
}
}
/* ---------------- Conversion from/to TreeBins -------------- */
/**
* Replaces all linked nodes in bin at given index unless table is
* too small, in which case resizes instead.
*/
private void treeifyBin(Node<V>[] tab, int index) {
Node<V> b;
int n, sc;
if (tab != null) {
if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
tryPresize(n << 1);
}
else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
synchronized (b) {
if (tabAt(tab, index) == b) {
TreeNode<V> hd = null, tl = null;
for (Node<V> e = b; e != null; e = e.next) {
TreeNode<V> p =
new TreeNode<V>(e.hash, e.key, e.val,
null, null);
if ((p.prev = tl) == null) {
hd = p;
}
else {
tl.next = p;
}
tl = p;
}
setTabAt(tab, index, new TreeBin<V>(hd));
}
}
}
}
}
/**
* Returns a list on non-TreeNodes replacing those in given list.
*/
static <V> Node<V> untreeify(Node<V> b) {
Node<V> hd = null, tl = null;
for (Node<V> q = b; q != null; q = q.next) {
Node<V> p = new Node<V>(q.hash, q.key, q.val, null);
if (tl == null) {
hd = p;
}
else {
tl.next = p;
}
tl = p;
}
return hd;
}
/* ---------------- TreeNodes -------------- */
/**
* Nodes for use in TreeBins
*/
static final class TreeNode<V> extends Node<V> {
TreeNode<V> parent; // red-black tree links
TreeNode<V> left;
TreeNode<V> right;
TreeNode<V> prev; // needed to unlink next upon deletion
boolean red;
TreeNode(int hash, int key, V val, Node<V> next, TreeNode<V> parent) {
super(hash, key, val, next);
this.parent = parent;
}
@Override
Node<V> find(int h, int k) {
return findTreeNode(h, k);
}
/**
* Returns the TreeNode (or null if not found) for the given key
* starting at given root.
*/
final TreeNode<V> findTreeNode(int h, int k) {
TreeNode<V> p = this;
do {
int ph;
TreeNode<V> q;
TreeNode<V> pl = p.left;
TreeNode<V> pr = p.right;
if ((ph = p.hash) > h) {
p = pl;
}
else if (ph < h) {
p = pr;
}
else if (p.key == k) {
return p;
}
else if (pl == null) {
p = pr;
}
else if (pr == null) {
p = pl;
}
else if ((q = pr.findTreeNode(h, k)) != null) {
return q;
}
else {
p = pl;
}
}
while (p != null);
return null;
}
}
/* ---------------- TreeBins -------------- */
/**
* TreeNodes used at the heads of bins. TreeBins do not hold user
* keys or values, but instead point to list of TreeNodes and
* their root. They also maintain a parasitic read-write lock
* forcing writers (who hold bin lock) to wait for readers (who do
* not) to complete before tree restructuring operations.
*/
static final class TreeBin<V> extends Node<V> {
TreeNode<V> root;
volatile TreeNode<V> first;
volatile Thread waiter;
volatile int lockState;
// values for lockState
static final int WRITER = 1; // set while holding write lock
static final int WAITER = 2; // set when waiting for write lock
static final int READER = 4; // increment value for setting read lock
/**
* Creates bin with initial set of nodes headed by b.
*/
TreeBin(TreeNode<V> b) {
super(TREEBIN, 0, null, null);
first = b;
TreeNode<V> r = null;
for (TreeNode<V> x = b, next; x != null; x = next) {
next = (TreeNode<V>)x.next;
x.left = x.right = null;
if (r == null) {
x.parent = null;
x.red = false;
r = x;
}
else {
int h = x.hash;
for (TreeNode<V> p = r; ; ) {
int dir, ph;
if ((ph = p.hash) > h) {
dir = -1;
}
else if (ph < h) {
dir = 1;
}
else {
dir = 0;
}
TreeNode<V> xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
x.parent = xp;
if (dir <= 0) {
xp.left = x;
}
else {
xp.right = x;
}
r = balanceInsertion(r, x);
break;
}
}
}
}
root = r;
assert checkInvariants(root);
}
/**
* Acquires write lock for tree restructuring.
*/
private void lockRoot() {
if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER)) {
contendedLock(); // offload to separate method
}
}
/**
* Releases write lock for tree restructuring.
*/
private void unlockRoot() {
lockState = 0;
}
/**
* Possibly blocks awaiting root lock.
*/
private void contendedLock() {
boolean waiting = false;
for (int s; ; ) {
if (((s = lockState) & ~WAITER) == 0) {
if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
if (waiting) {
waiter = null;
}
return;
}
}
else if ((s & WAITER) == 0) {
if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
waiting = true;
waiter = Thread.currentThread();
}
}
else if (waiting) {
LockSupport.park(this);
}
}
}
/**
* Returns matching node or null if none. Tries to search
* using tree comparisons from root, but continues linear
* search when lock not available.
*/
@Override
final Node<V> find(int h, int k) {
for (Node<V> e = first; e != null; ) {
int s;
if (((s = lockState) & (WAITER | WRITER)) != 0) {
if ((e.key == k)) {
return e;
}
e = e.next;
}
else if (U.compareAndSwapInt(this, LOCKSTATE, s,
s + READER)) {
TreeNode<V> r;
TreeNode<V> p;
try {
p = ((r = root) == null ? null :
r.findTreeNode(h, k));
}
finally {
Thread w;
if (getAndAddInt(this, LOCKSTATE, -READER) ==
(READER | WAITER) && (w = waiter) != null) {
LockSupport.unpark(w);
}
}
return p;
}
}
return null;
}
private int getAndAddInt(Object var1, long var2, int var4) {
int var5;
do {
var5 = U.getIntVolatile(var1, var2);
} while(!U.compareAndSwapInt(var1, var2, var5, var5 + var4));
return var5;
}
/**
* Finds or adds a node.
*
* @return null if added
*/
final TreeNode<V> putTreeVal(int h, int k, V v) {
boolean searched = false;
for (TreeNode<V> p = root; ; ) {
int dir, ph;
if (p == null) {
first = root = new TreeNode<V>(h, k, v, null, null);
break;
}
else if ((ph = p.hash) > h) {
dir = -1;
}
else if (ph < h) {
dir = 1;
}
else if (p.key == k) {
return p;
}
else {
if (!searched) {
TreeNode<V> q, ch;
searched = true;
if (((ch = p.left) != null &&
(q = ch.findTreeNode(h, k)) != null) ||
((ch = p.right) != null &&
(q = ch.findTreeNode(h, k)) != null)) {
return q;
}
}
dir = 0;
}
TreeNode<V> xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
TreeNode<V> x, f = first;
first = x = new TreeNode<V>(h, k, v, f, xp);
if (f != null) {
f.prev = x;
}
if (dir <= 0) {
xp.left = x;
}
else {
xp.right = x;
}
if (!xp.red) {
x.red = true;
}
else {
lockRoot();
try {
root = balanceInsertion(root, x);
}
finally {
unlockRoot();
}
}
break;
}
}
assert checkInvariants(root);
return null;
}
/**
* Removes the given node, that must be present before this
* call. This is messier than typical red-black deletion code
* because we cannot swap the contents of an interior node
* with a leaf successor that is pinned by "next" pointers
* that are accessible independently of lock. So instead we
* swap the tree linkages.
*
* @return true if now too small, so should be untreeified
*/
final boolean removeTreeNode(TreeNode<V> p) {
TreeNode<V> next = (TreeNode<V>)p.next;
TreeNode<V> pred = p.prev; // unlink traversal pointers
TreeNode<V> r, rl;
if (pred == null) {
first = next;
}
else {
pred.next = next;
}
if (next != null) {
next.prev = pred;
}
if (first == null) {
root = null;
return true;
}
if ((r = root) == null || r.right == null || // too small
(rl = r.left) == null || rl.left == null) {
return true;
}
lockRoot();
try {
TreeNode<V> replacement;
TreeNode<V> pl = p.left;
TreeNode<V> pr = p.right;
if (pl != null && pr != null) {
TreeNode<V> s = pr, sl;
while ((sl = s.left) != null) // find successor
{
s = sl;
}
boolean c = s.red;
s.red = p.red;
p.red = c; // swap colors
TreeNode<V> sr = s.right;
TreeNode<V> pp = p.parent;
if (s == pr) { // p was s's direct parent
p.parent = s;
s.right = p;
}
else {
TreeNode<V> sp = s.parent;
if ((p.parent = sp) != null) {
if (s == sp.left) {
sp.left = p;
}
else {
sp.right = p;
}
}
if ((s.right = pr) != null) {
pr.parent = s;
}
}
p.left = null;
if ((p.right = sr) != null) {
sr.parent = p;
}
if ((s.left = pl) != null) {
pl.parent = s;
}
if ((s.parent = pp) == null) {
r = s;
}
else if (p == pp.left) {
pp.left = s;
}
else {
pp.right = s;
}
if (sr != null) {
replacement = sr;
}
else {
replacement = p;
}
}
else if (pl != null) {
replacement = pl;
}
else if (pr != null) {
replacement = pr;
}
else {
replacement = p;
}
if (replacement != p) {
TreeNode<V> pp = replacement.parent = p.parent;
if (pp == null) {
r = replacement;
}
else if (p == pp.left) {
pp.left = replacement;
}
else {
pp.right = replacement;
}
p.left = p.right = p.parent = null;
}
root = (p.red) ? r : balanceDeletion(r, replacement);
if (p == replacement) { // detach pointers
TreeNode<V> pp;
if ((pp = p.parent) != null) {
if (p == pp.left) {
pp.left = null;
}
else if (p == pp.right) {
pp.right = null;
}
p.parent = null;
}
}
}
finally {
unlockRoot();
}
assert checkInvariants(root);
return false;
}
/* ------------------------------------------------------------ */
// Red-black tree methods, all adapted from CLR
static <V> TreeNode<V> rotateLeft(TreeNode<V> root,
TreeNode<V> p) {
TreeNode<V> r, pp, rl;
if (p != null && (r = p.right) != null) {
if ((rl = p.right = r.left) != null) {
rl.parent = p;
}
if ((pp = r.parent = p.parent) == null) {
(root = r).red = false;
}
else if (pp.left == p) {
pp.left = r;
}
else {
pp.right = r;
}
r.left = p;
p.parent = r;
}
return root;
}
static <V> TreeNode<V> rotateRight(TreeNode<V> root,
TreeNode<V> p) {
TreeNode<V> l, pp, lr;
if (p != null && (l = p.left) != null) {
if ((lr = p.left = l.right) != null) {
lr.parent = p;
}
if ((pp = l.parent = p.parent) == null) {
(root = l).red = false;
}
else if (pp.right == p) {
pp.right = l;
}
else {
pp.left = l;
}
l.right = p;
p.parent = l;
}
return root;
}
static <V> TreeNode<V> balanceInsertion(TreeNode<V> root,
TreeNode<V> x) {
x.red = true;
for (TreeNode<V> xp, xpp, xppl, xppr; ; ) {
if ((xp = x.parent) == null) {
x.red = false;
return x;
}
else if (!xp.red || (xpp = xp.parent) == null) {
return root;
}
if (xp == (xppl = xpp.left)) {
if ((xppr = xpp.right) != null && xppr.red) {
xppr.red = false;
xp.red = false;
xpp.red = true;
x = xpp;
}
else {
if (x == xp.right) {
root = rotateLeft(root, x = xp);
xpp = (xp = x.parent) == null ? null : xp.parent;
}
if (xp != null) {
xp.red = false;
if (xpp != null) {
xpp.red = true;
root = rotateRight(root, xpp);
}
}
}
}
else {
if (xppl != null && xppl.red) {
xppl.red = false;
xp.red = false;
xpp.red = true;
x = xpp;
}
else {
if (x == xp.left) {
root = rotateRight(root, x = xp);
xpp = (xp = x.parent) == null ? null : xp.parent;
}
if (xp != null) {
xp.red = false;
if (xpp != null) {
xpp.red = true;
root = rotateLeft(root, xpp);
}
}
}
}
}
}
static <V> TreeNode<V> balanceDeletion(TreeNode<V> root,
TreeNode<V> x) {
for (TreeNode<V> xp, xpl, xpr; ; ) {
if (x == null || x == root) {
return root;
}
else if ((xp = x.parent) == null) {
x.red = false;
return x;
}
else if (x.red) {
x.red = false;
return root;
}
else if ((xpl = xp.left) == x) {
if ((xpr = xp.right) != null && xpr.red) {
xpr.red = false;
xp.red = true;
root = rotateLeft(root, xp);
xpr = (xp = x.parent) == null ? null : xp.right;
}
if (xpr == null) {
x = xp;
}
else {
TreeNode<V> sl = xpr.left, sr = xpr.right;
if ((sr == null || !sr.red) &&
(sl == null || !sl.red)) {
xpr.red = true;
x = xp;
}
else {
if (sr == null || !sr.red) {
if (sl != null) {
sl.red = false;
}
xpr.red = true;
root = rotateRight(root, xpr);
xpr = (xp = x.parent) == null ?
null : xp.right;
}
if (xpr != null) {
xpr.red = (xp == null) ? false : xp.red;
if ((sr = xpr.right) != null) {
sr.red = false;
}
}
if (xp != null) {
xp.red = false;
root = rotateLeft(root, xp);
}
x = root;
}
}
}
else { // symmetric
if (xpl != null && xpl.red) {
xpl.red = false;
xp.red = true;
root = rotateRight(root, xp);
xpl = (xp = x.parent) == null ? null : xp.left;
}
if (xpl == null) {
x = xp;
}
else {
TreeNode<V> sl = xpl.left, sr = xpl.right;
if ((sl == null || !sl.red) &&
(sr == null || !sr.red)) {
xpl.red = true;
x = xp;
}
else {
if (sl == null || !sl.red) {
if (sr != null) {
sr.red = false;
}
xpl.red = true;
root = rotateLeft(root, xpl);
xpl = (xp = x.parent) == null ?
null : xp.left;
}
if (xpl != null) {
xpl.red = (xp == null) ? false : xp.red;
if ((sl = xpl.left) != null) {
sl.red = false;
}
}
if (xp != null) {
xp.red = false;
root = rotateRight(root, xp);
}
x = root;
}
}
}
}
}
/**
* Recursive invariant check
*/
static <V> boolean checkInvariants(TreeNode<V> t) {
TreeNode<V> tp = t.parent, tl = t.left, tr = t.right,
tb = t.prev, tn = (TreeNode<V>)t.next;
if (tb != null && tb.next != t) {
return false;
}
if (tn != null && tn.prev != t) {
return false;
}
if (tp != null && t != tp.left && t != tp.right) {
return false;
}
if (tl != null && (tl.parent != t || tl.hash > t.hash)) {
return false;
}
if (tr != null && (tr.parent != t || tr.hash < t.hash)) {
return false;
}
if (t.red && tl != null && tl.red && tr != null && tr.red) {
return false;
}
if (tl != null && !checkInvariants(tl)) {
return false;
}
if (tr != null && !checkInvariants(tr)) {
return false;
}
return true;
}
private static final sun.misc.Unsafe U;
private static final long LOCKSTATE;
static {
try {
U = getUnsafe();
Class<?> k = TreeBin.class;
LOCKSTATE = U.objectFieldOffset
(k.getDeclaredField("lockState"));
}
catch (Exception e) {
throw new Error(e);
}
}
}
/* ----------------Table Traversal -------------- */
/**
* Records the table, its length, and current traversal index for a
* traverser that must process a region of a forwarded table before
* proceeding with current table.
*/
static final class TableStack<V> {
int length;
int index;
Node<V>[] tab;
TableStack<V> next;
}
/**
* Encapsulates traversal for methods such as containsValue; also
* serves as a base class for other iterators and spliterators.
* <p/>
* Method advance visits once each still-valid node that was
* reachable upon iterator construction. It might miss some that
* were added to a bin after the bin was visited, which is OK wrt
* consistency guarantees. Maintaining this property in the face
* of possible ongoing resizes requires a fair amount of
* bookkeeping state that is difficult to optimize away amidst
* volatile accesses. Even so, traversal maintains reasonable
* throughput.
* <p/>
* Normally, iteration proceeds bin-by-bin traversing lists.
* However, if the table has been resized, then all future steps
* must traverse both the bin at the current index as well as at
* (index + baseSize); and so on for further resizings. To
* paranoically cope with potential sharing by users of iterators
* across threads, iteration terminates if a bounds checks fails
* for a table read.
*/
static class Traverser<V> {
Node<V>[] tab; // current table; updated if resized
Node<V> next; // the next entry to use
TableStack<V> stack;
TableStack<V> spare; // to save/restore on ForwardingNodes
int index; // index of bin to use next
int baseIndex; // current index of initial table
int baseLimit; // index bound for initial table
final int baseSize; // initial table size
Traverser(Node<V>[] tab, int size, int index, int limit) {
this.tab = tab;
baseSize = size;
baseIndex = this.index = index;
baseLimit = limit;
next = null;
}
/**
* Advances if possible, returning next valid node, or null if none.
*/
final Node<V> advance() {
Node<V> e;
if ((e = next) != null) {
e = e.next;
}
for (; ; ) {
Node<V>[] t;
int i; // must use locals in checks
int n;
if (e != null) {
return next = e;
}
if (baseIndex >= baseLimit || (t = tab) == null ||
(n = t.length) <= (i = index) || i < 0) {
return next = null;
}
if ((e = tabAt(t, i)) != null && e.hash < 0) {
if (e instanceof ForwardingNode) {
tab = ((ForwardingNode<V>)e).nextTable;
e = null;
pushState(t, i, n);
continue;
}
else if (e instanceof TreeBin) {
e = ((TreeBin<V>)e).first;
}
else {
e = null;
}
}
if (stack != null) {
recoverState(n);
}
else if ((index = i + baseSize) >= n) {
index = ++baseIndex; // visit upper slots if present
}
}
}
/**
* Saves traversal state upon encountering a forwarding node.
*/
private void pushState(Node<V>[] t, int i, int n) {
TableStack<V> s = spare; // reuse if possible
if (s != null) {
spare = s.next;
}
else {
s = new TableStack<V>();
}
s.tab = t;
s.length = n;
s.index = i;
s.next = stack;
stack = s;
}
/**
* Possibly pops traversal state.
*
* @param n length of current table
*/
private void recoverState(int n) {
TableStack<V> s;
int len;
while ((s = stack) != null && (index += (len = s.length)) >= n) {
n = len;
index = s.index;
tab = s.tab;
s.tab = null;
TableStack<V> next = s.next;
s.next = spare; // save for reuse
stack = next;
spare = s;
}
if (s == null && (index += baseSize) >= n) {
index = ++baseIndex;
}
}
}
/**
* Base of key, value, and entry Iterators. Adds fields to
* Traverser to support iterator.remove.
*/
static class BaseIterator<V> extends Traverser<V> {
final ConcurrentIntObjectHashMap<V> map;
Node<V> lastReturned;
BaseIterator(Node<V>[] tab, int size, int index, int limit,
ConcurrentIntObjectHashMap<V> map) {
super(tab, size, index, limit);
this.map = map;
advance();
}
public final boolean hasNext() {
return next != null;
}
public final boolean hasMoreElements() {
return next != null;
}
public final void remove() {
Node<V> p;
if ((p = lastReturned) == null) {
throw new IllegalStateException();
}
lastReturned = null;
map.replaceNode(p.key, null, null);
}
}
static final class ValueIterator<V> extends BaseIterator<V>
implements Iterator<V>, Enumeration<V> {
ValueIterator(Node<V>[] tab, int index, int size, int limit,
ConcurrentIntObjectHashMap<V> map) {
super(tab, index, size, limit, map);
}
@Override
public final V next() {
Node<V> p;
if ((p = next) == null) {
throw new NoSuchElementException();
}
V v = p.val;
lastReturned = p;
advance();
return v;
}
@Override
public final V nextElement() {
return next();
}
}
static final class EntryIterator<V> extends BaseIterator<V>
implements Iterator<IntEntry<V>> {
EntryIterator(Node<V>[] tab, int index, int size, int limit,
ConcurrentIntObjectHashMap<V> map) {
super(tab, index, size, limit, map);
}
@Override
public final IntEntry<V> next() {
Node<V> p;
if ((p = next) == null) {
throw new NoSuchElementException();
}
final int k = p.key;
final V v = p.val;
lastReturned = p;
advance();
return new IntEntry<V>() {
@Override
public int getKey() {
return k;
}
@NotNull
@Override
public V getValue() {
return v;
}
};
}
}
// Parallel bulk operations
/* ----------------Views -------------- */
/**
* Base class for views.
*/
abstract static class CollectionView<V, E> implements Collection<E> {
final ConcurrentIntObjectHashMap<V> map;
CollectionView(ConcurrentIntObjectHashMap<V> map) {
this.map = map;
}
/**
* Returns the map backing this view.
*
* @return the map backing this view
*/
public ConcurrentIntObjectHashMap<V> getMap() {
return map;
}
/**
* Removes all of the elements from this view, by removing all
* the mappings from the map backing this view.
*/
@Override
public final void clear() {
map.clear();
}
@Override
public final int size() {
return map.size();
}
@Override
public final boolean isEmpty() {
return map.isEmpty();
}
// implementations below rely on concrete classes supplying these
// abstract methods
/**
* Returns an iterator over the elements in this collection.
* <p/>
* <p>The returned iterator is
* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
*
* @return an iterator over the elements in this collection
*/
@NotNull
@Override
public abstract Iterator<E> iterator();
@Override
public abstract boolean contains(Object o);
@Override
public abstract boolean remove(Object o);
private static final String oomeMsg = "Required array size too large";
@NotNull
@Override
public final Object[] toArray() {
long sz = map.mappingCount();
if (sz > MAX_ARRAY_SIZE) {
throw new OutOfMemoryError(oomeMsg);
}
int n = (int)sz;
Object[] r = new Object[n];
int i = 0;
for (E e : this) {
if (i == n) {
if (n >= MAX_ARRAY_SIZE) {
throw new OutOfMemoryError(oomeMsg);
}
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) {
n = MAX_ARRAY_SIZE;
}
else {
n += (n >>> 1) + 1;
}
r = Arrays.copyOf(r, n);
}
r[i++] = e;
}
return (i == n) ? r : Arrays.copyOf(r, i);
}
@NotNull
@Override
@SuppressWarnings("unchecked")
public final <T> T[] toArray(@NotNull T[] a) {
long sz = map.mappingCount();
if (sz > MAX_ARRAY_SIZE) {
throw new OutOfMemoryError(oomeMsg);
}
int m = (int)sz;
T[] r = (a.length >= m) ? a :
(T[])java.lang.reflect.Array
.newInstance(a.getClass().getComponentType(), m);
int n = r.length;
int i = 0;
for (E e : this) {
if (i == n) {
if (n >= MAX_ARRAY_SIZE) {
throw new OutOfMemoryError(oomeMsg);
}
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) {
n = MAX_ARRAY_SIZE;
}
else {
n += (n >>> 1) + 1;
}
r = Arrays.copyOf(r, n);
}
r[i++] = (T)e;
}
if (a == r && i < n) {
r[i] = null; // null-terminate
return r;
}
return (i == n) ? r : Arrays.copyOf(r, i);
}
/**
* Returns a string representation of this collection.
* The string representation consists of the string representations
* of the collection's elements in the order they are returned by
* its iterator, enclosed in square brackets ({@code "[]"}).
* Adjacent elements are separated by the characters {@code ", "}
* (comma and space). Elements are converted to strings as by
* {@link String#valueOf(Object)}.
*
* @return a string representation of this collection
*/
@Override
public final String toString() {
StringBuilder sb = new StringBuilder();
sb.append('[');
Iterator<E> it = iterator();
if (it.hasNext()) {
for (; ; ) {
Object e = it.next();
sb.append(e == this ? "(this Collection)" : e);
if (!it.hasNext()) {
break;
}
sb.append(',').append(' ');
}
}
return sb.append(']').toString();
}
@Override
public final boolean containsAll(@NotNull Collection<?> c) {
if (c != this) {
for (Object e : c) {
if (e == null || !contains(e)) {
return false;
}
}
}
return true;
}
@Override
public final boolean removeAll(@NotNull Collection<?> c) {
boolean modified = false;
for (Iterator<E> it = iterator(); it.hasNext(); ) {
if (c.contains(it.next())) {
it.remove();
modified = true;
}
}
return modified;
}
@Override
public final boolean retainAll(@NotNull Collection<?> c) {
boolean modified = false;
for (Iterator<E> it = iterator(); it.hasNext(); ) {
if (!c.contains(it.next())) {
it.remove();
modified = true;
}
}
return modified;
}
}
/**
* A view of a ConcurrentHashMap as a {@link Collection} of
* values, in which additions are disabled. This class cannot be
* directly instantiated. See {@link #values()}.
*/
static final class ValuesView<V> extends CollectionView<V, V> implements Collection<V> {
ValuesView(ConcurrentIntObjectHashMap<V> map) {
super(map);
}
@Override
public final boolean contains(Object o) {
return map.containsValue(o);
}
@Override
public final boolean remove(Object o) {
if (o != null) {
for (Iterator<V> it = iterator(); it.hasNext(); ) {
if (o.equals(it.next())) {
it.remove();
return true;
}
}
}
return false;
}
@NotNull
@Override
public final Iterator<V> iterator() {
ConcurrentIntObjectHashMap<V> m = map;
Node<V>[] t;
int f = (t = m.table) == null ? 0 : t.length;
return new ValueIterator<V>(t, f, 0, f, m);
}
@Override
public final boolean add(V e) {
throw new UnsupportedOperationException();
}
@Override
public final boolean addAll(@NotNull Collection<? extends V> c) {
throw new UnsupportedOperationException();
}
}
@NotNull
@Override
public Iterable<IntEntry<V>> entries() {
return new EntrySetView<V>(this);
}
/**
* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
* entries. This class cannot be directly instantiated. See
* {@link #entrySet()}.
*/
static final class EntrySetView<V> extends CollectionView<V, IntEntry<V>>
implements Set<IntEntry<V>> {
EntrySetView(ConcurrentIntObjectHashMap<V> map) {
super(map);
}
@Override
public boolean contains(Object o) {
Object v;
Object r;
IntEntry<?> e;
return ((o instanceof IntEntry) &&
(r = map.get((e = (IntEntry)o).getKey())) != null &&
(v = e.getValue()) != null &&
(v == r || v.equals(r)));
}
@Override
public boolean remove(Object o) {
Object v;
IntEntry<?> e;
return ((o instanceof Map.Entry) &&
(e = (IntEntry<?>)o) != null &&
(v = e.getValue()) != null &&
map.remove(e.getKey(), v));
}
/**
* @return an iterator over the entries of the backing map
*/
@NotNull
@Override
public Iterator<IntEntry<V>> iterator() {
ConcurrentIntObjectHashMap<V> m = map;
Node<V>[] t;
int f = (t = m.table) == null ? 0 : t.length;
return new EntryIterator<V>(t, f, 0, f, m);
}
@Override
public boolean add(IntEntry<V> e) {
return map.putVal(e.getKey(), e.getValue(), false) == null;
}
@Override
public boolean addAll(Collection<? extends IntEntry<V>> c) {
boolean added = false;
for (IntEntry<V> e : c) {
if (add(e)) {
added = true;
}
}
return added;
}
@Override
public final int hashCode() {
int h = 0;
Node<V>[] t;
if ((t = map.table) != null) {
Traverser<V> it = new Traverser<V>(t, t.length, 0, t.length);
for (Node<V> p; (p = it.advance()) != null; ) {
h += p.hashCode();
}
}
return h;
}
@Override
public final boolean equals(Object o) {
Set<?> c;
return ((o instanceof Set) &&
((c = (Set<?>)o) == this ||
(containsAll(c) && c.containsAll(this))));
}
}
// -------------------------------------------------------
// Unsafe mechanics
private static final sun.misc.Unsafe U;
private static final long SIZECTL;
private static final long TRANSFERINDEX;
private static final long BASECOUNT;
private static final long CELLSBUSY;
private static final long CELLVALUE;
private static final long ABASE;
private static final int ASHIFT;
static {
try {
U = getUnsafe();
Class<?> k = ConcurrentIntObjectHashMap.class;
SIZECTL = U.objectFieldOffset
(k.getDeclaredField("sizeCtl"));
TRANSFERINDEX = U.objectFieldOffset
(k.getDeclaredField("transferIndex"));
BASECOUNT = U.objectFieldOffset
(k.getDeclaredField("baseCount"));
CELLSBUSY = U.objectFieldOffset
(k.getDeclaredField("cellsBusy"));
Class<?> ck = ConcurrentHashMap.CounterCell.class;
CELLVALUE = U.objectFieldOffset
(ck.getDeclaredField("value"));
Class<?> ak = Node[].class;
ABASE = U.arrayBaseOffset(ak);
int scale = U.arrayIndexScale(ak);
if ((scale & (scale - 1)) != 0) {
throw new Error("data type scale not a power of two");
}
ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
}
catch (Exception e) {
throw new Error(e);
}
}
/**
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package.
* Replace with a simple call to Unsafe.getUnsafe when integrating
* into a jdk.
*
* @return a sun.misc.Unsafe
*/
private static Unsafe getUnsafe() {
return AtomicFieldUpdater.getUnsafe();
}
////////////////////// IJ specific
/**
* @return value if there is no entry in the map, or corresponding value if entry already exists
*/
@Override
@NotNull
public V cacheOrGet(final int key, @NotNull final V defaultValue) {
V v = get(key);
if (v != null) return v;
V prev = putIfAbsent(key, defaultValue);
return prev == null ? defaultValue : prev;
}
}