src/jdk.internal.vm.compiler/share/classes/org.graalvm.collections/src/org/graalvm/collections/EconomicMapImpl.java
changeset 48861 47f19ff9903c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.collections/src/org/graalvm/collections/EconomicMapImpl.java	Fri Feb 02 17:28:17 2018 -0800
@@ -0,0 +1,857 @@
+/*
+ * Copyright (c) 2017, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.graalvm.collections;
+
+import java.util.Iterator;
+import java.util.Objects;
+import java.util.function.BiFunction;
+
+/**
+ * Implementation of a map with a memory-efficient structure that always preserves insertion order
+ * when iterating over keys. Particularly efficient when number of entries is 0 or smaller equal
+ * {@link #INITIAL_CAPACITY} or smaller 256.
+ *
+ * The key/value pairs are kept in an expanding flat object array with keys at even indices and
+ * values at odd indices. If the map has smaller or equal to {@link #HASH_THRESHOLD} entries, there
+ * is no additional hash data structure and comparisons are done via linear checking of the
+ * key/value pairs. For the case where the equality check is particularly cheap (e.g., just an
+ * object identity comparison), this limit below which the map is without an actual hash table is
+ * higher and configured at {@link #HASH_THRESHOLD_IDENTITY_COMPARE}.
+ *
+ * When the hash table needs to be constructed, the field {@link #hashArray} becomes a new hash
+ * array where an entry of 0 means no hit and otherwise denotes the entry number in the
+ * {@link #entries} array. The hash array is interpreted as an actual byte array if the indices fit
+ * within 8 bit, or as an array of short values if the indices fit within 16 bit, or as an array of
+ * integer values in other cases.
+ *
+ * Hash collisions are handled by chaining a linked list of {@link CollisionLink} objects that take
+ * the place of the values in the {@link #entries} array.
+ *
+ * Removing entries will put {@code null} into the {@link #entries} array. If the occupation of the
+ * map falls below a specific threshold, the map will be compressed via the
+ * {@link #maybeCompress(int)} method.
+ */
+final class EconomicMapImpl<K, V> implements EconomicMap<K, V>, EconomicSet<K> {
+
+    /**
+     * Initial number of key/value pair entries that is allocated in the first entries array.
+     */
+    private static final int INITIAL_CAPACITY = 4;
+
+    /**
+     * Maximum number of entries that are moved linearly forward if a key is removed.
+     */
+    private static final int COMPRESS_IMMEDIATE_CAPACITY = 8;
+
+    /**
+     * Minimum number of key/value pair entries added when the entries array is increased in size.
+     */
+    private static final int MIN_CAPACITY_INCREASE = 8;
+
+    /**
+     * Number of entries above which a hash table is created.
+     */
+    private static final int HASH_THRESHOLD = 4;
+
+    /**
+     * Number of entries above which a hash table is created when equality can be checked with
+     * object identity.
+     */
+    private static final int HASH_THRESHOLD_IDENTITY_COMPARE = 8;
+
+    /**
+     * Maximum number of entries allowed in the map.
+     */
+    private static final int MAX_ELEMENT_COUNT = Integer.MAX_VALUE >> 1;
+
+    /**
+     * Number of entries above which more than 1 byte is necessary for the hash index.
+     */
+    private static final int LARGE_HASH_THRESHOLD = ((1 << Byte.SIZE) << 1);
+
+    /**
+     * Number of entries above which more than 2 bytes are are necessary for the hash index.
+     */
+    private static final int VERY_LARGE_HASH_THRESHOLD = (LARGE_HASH_THRESHOLD << Byte.SIZE);
+
+    /**
+     * Total number of entries (actual entries plus deleted entries).
+     */
+    private int totalEntries;
+
+    /**
+     * Number of deleted entries.
+     */
+    private int deletedEntries;
+
+    /**
+     * Entries array with even indices storing keys and odd indices storing values.
+     */
+    private Object[] entries;
+
+    /**
+     * Hash array that is interpreted either as byte or short or int array depending on number of
+     * map entries.
+     */
+    private byte[] hashArray;
+
+    /**
+     * The strategy used for comparing keys or {@code null} for denoting special strategy
+     * {@link Equivalence#IDENTITY}.
+     */
+    private final Equivalence strategy;
+
+    /**
+     * Intercept method for debugging purposes.
+     */
+    private static <K, V> EconomicMapImpl<K, V> intercept(EconomicMapImpl<K, V> map) {
+        return map;
+    }
+
+    public static <K, V> EconomicMapImpl<K, V> create(Equivalence strategy, boolean isSet) {
+        return intercept(new EconomicMapImpl<>(strategy, isSet));
+    }
+
+    public static <K, V> EconomicMapImpl<K, V> create(Equivalence strategy, int initialCapacity, boolean isSet) {
+        return intercept(new EconomicMapImpl<>(strategy, initialCapacity, isSet));
+    }
+
+    public static <K, V> EconomicMapImpl<K, V> create(Equivalence strategy, UnmodifiableEconomicMap<K, V> other, boolean isSet) {
+        return intercept(new EconomicMapImpl<>(strategy, other, isSet));
+    }
+
+    public static <K, V> EconomicMapImpl<K, V> create(Equivalence strategy, UnmodifiableEconomicSet<K> other, boolean isSet) {
+        return intercept(new EconomicMapImpl<>(strategy, other, isSet));
+    }
+
+    private EconomicMapImpl(Equivalence strategy, boolean isSet) {
+        if (strategy == Equivalence.IDENTITY) {
+            this.strategy = null;
+        } else {
+            this.strategy = strategy;
+        }
+        this.isSet = isSet;
+    }
+
+    private EconomicMapImpl(Equivalence strategy, int initialCapacity, boolean isSet) {
+        this(strategy, isSet);
+        init(initialCapacity);
+    }
+
+    private EconomicMapImpl(Equivalence strategy, UnmodifiableEconomicMap<K, V> other, boolean isSet) {
+        this(strategy, isSet);
+        if (!initFrom(other)) {
+            init(other.size());
+            putAll(other);
+        }
+    }
+
+    private EconomicMapImpl(Equivalence strategy, UnmodifiableEconomicSet<K> other, boolean isSet) {
+        this(strategy, isSet);
+        if (!initFrom(other)) {
+            init(other.size());
+            addAll(other);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private boolean initFrom(Object o) {
+        if (o instanceof EconomicMapImpl) {
+            EconomicMapImpl<K, V> otherMap = (EconomicMapImpl<K, V>) o;
+            // We are only allowed to directly copy if the strategies of the two maps are the same.
+            if (strategy == otherMap.strategy) {
+                totalEntries = otherMap.totalEntries;
+                deletedEntries = otherMap.deletedEntries;
+                if (otherMap.entries != null) {
+                    entries = otherMap.entries.clone();
+                }
+                if (otherMap.hashArray != null) {
+                    hashArray = otherMap.hashArray.clone();
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void init(int size) {
+        if (size > INITIAL_CAPACITY) {
+            entries = new Object[size << 1];
+        }
+    }
+
+    /**
+     * Links the collisions. Needs to be immutable class for allowing efficient shallow copy from
+     * other map on construction.
+     */
+    private static final class CollisionLink {
+
+        CollisionLink(Object value, int next) {
+            this.value = value;
+            this.next = next;
+        }
+
+        final Object value;
+
+        /**
+         * Index plus one of the next entry in the collision link chain.
+         */
+        final int next;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public V get(K key) {
+        Objects.requireNonNull(key);
+
+        int index = find(key);
+        if (index != -1) {
+            return (V) getValue(index);
+        }
+        return null;
+    }
+
+    private int find(K key) {
+        if (hasHashArray()) {
+            return findHash(key);
+        } else {
+            return findLinear(key);
+        }
+    }
+
+    private int findLinear(K key) {
+        for (int i = 0; i < totalEntries; i++) {
+            Object entryKey = entries[i << 1];
+            if (entryKey != null && compareKeys(key, entryKey)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private boolean compareKeys(Object key, Object entryKey) {
+        if (key == entryKey) {
+            return true;
+        }
+        if (strategy != null && strategy != Equivalence.IDENTITY_WITH_SYSTEM_HASHCODE) {
+            if (strategy == Equivalence.DEFAULT) {
+                return key.equals(entryKey);
+            } else {
+                return strategy.equals(key, entryKey);
+            }
+        }
+        return false;
+    }
+
+    private int findHash(K key) {
+        int index = getHashArray(getHashIndex(key)) - 1;
+        if (index != -1) {
+            Object entryKey = getKey(index);
+            if (compareKeys(key, entryKey)) {
+                return index;
+            } else {
+                Object entryValue = getRawValue(index);
+                if (entryValue instanceof CollisionLink) {
+                    return findWithCollision(key, (CollisionLink) entryValue);
+                }
+            }
+        }
+
+        return -1;
+    }
+
+    private int findWithCollision(K key, CollisionLink initialEntryValue) {
+        int index;
+        Object entryKey;
+        CollisionLink entryValue = initialEntryValue;
+        while (true) {
+            CollisionLink collisionLink = entryValue;
+            index = collisionLink.next;
+            entryKey = getKey(index);
+            if (compareKeys(key, entryKey)) {
+                return index;
+            } else {
+                Object value = getRawValue(index);
+                if (value instanceof CollisionLink) {
+                    entryValue = (CollisionLink) getRawValue(index);
+                } else {
+                    return -1;
+                }
+            }
+        }
+    }
+
+    private int getHashArray(int index) {
+        if (entries.length < LARGE_HASH_THRESHOLD) {
+            return (hashArray[index] & 0xFF);
+        } else if (entries.length < VERY_LARGE_HASH_THRESHOLD) {
+            int adjustedIndex = index << 1;
+            return (hashArray[adjustedIndex] & 0xFF) | ((hashArray[adjustedIndex + 1] & 0xFF) << 8);
+        } else {
+            int adjustedIndex = index << 2;
+            return (hashArray[adjustedIndex] & 0xFF) | ((hashArray[adjustedIndex + 1] & 0xFF) << 8) | ((hashArray[adjustedIndex + 2] & 0xFF) << 16) | ((hashArray[adjustedIndex + 3] & 0xFF) << 24);
+        }
+    }
+
+    private void setHashArray(int index, int value) {
+        if (entries.length < LARGE_HASH_THRESHOLD) {
+            hashArray[index] = (byte) value;
+        } else if (entries.length < VERY_LARGE_HASH_THRESHOLD) {
+            int adjustedIndex = index << 1;
+            hashArray[adjustedIndex] = (byte) value;
+            hashArray[adjustedIndex + 1] = (byte) (value >> 8);
+        } else {
+            int adjustedIndex = index << 2;
+            hashArray[adjustedIndex] = (byte) value;
+            hashArray[adjustedIndex + 1] = (byte) (value >> 8);
+            hashArray[adjustedIndex + 2] = (byte) (value >> 16);
+            hashArray[adjustedIndex + 3] = (byte) (value >> 24);
+        }
+    }
+
+    private int findAndRemoveHash(Object key) {
+        int hashIndex = getHashIndex(key);
+        int index = getHashArray(hashIndex) - 1;
+        if (index != -1) {
+            Object entryKey = getKey(index);
+            if (compareKeys(key, entryKey)) {
+                Object value = getRawValue(index);
+                int nextIndex = -1;
+                if (value instanceof CollisionLink) {
+                    CollisionLink collisionLink = (CollisionLink) value;
+                    nextIndex = collisionLink.next;
+                }
+                setHashArray(hashIndex, nextIndex + 1);
+                return index;
+            } else {
+                Object entryValue = getRawValue(index);
+                if (entryValue instanceof CollisionLink) {
+                    return findAndRemoveWithCollision(key, (CollisionLink) entryValue, index);
+                }
+            }
+        }
+
+        return -1;
+    }
+
+    private int findAndRemoveWithCollision(Object key, CollisionLink initialEntryValue, int initialIndexValue) {
+        int index;
+        Object entryKey;
+        CollisionLink entryValue = initialEntryValue;
+        int lastIndex = initialIndexValue;
+        while (true) {
+            CollisionLink collisionLink = entryValue;
+            index = collisionLink.next;
+            entryKey = getKey(index);
+            if (compareKeys(key, entryKey)) {
+                Object value = getRawValue(index);
+                if (value instanceof CollisionLink) {
+                    CollisionLink thisCollisionLink = (CollisionLink) value;
+                    setRawValue(lastIndex, new CollisionLink(collisionLink.value, thisCollisionLink.next));
+                } else {
+                    setRawValue(lastIndex, collisionLink.value);
+                }
+                return index;
+            } else {
+                Object value = getRawValue(index);
+                if (value instanceof CollisionLink) {
+                    entryValue = (CollisionLink) getRawValue(index);
+                    lastIndex = index;
+                } else {
+                    return -1;
+                }
+            }
+        }
+    }
+
+    private int getHashIndex(Object key) {
+        int hash;
+        if (strategy != null && strategy != Equivalence.DEFAULT) {
+            if (strategy == Equivalence.IDENTITY_WITH_SYSTEM_HASHCODE) {
+                hash = System.identityHashCode(key);
+            } else {
+                hash = strategy.hashCode(key);
+            }
+        } else {
+            hash = key.hashCode();
+        }
+        hash = hash ^ (hash >>> 16);
+        return hash & (getHashTableSize() - 1);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public V put(K key, V value) {
+        if (key == null) {
+            throw new UnsupportedOperationException("null not supported as key!");
+        }
+        int index = find(key);
+        if (index != -1) {
+            Object oldValue = getValue(index);
+            setValue(index, value);
+            return (V) oldValue;
+        }
+
+        int nextEntryIndex = totalEntries;
+        if (entries == null) {
+            entries = new Object[INITIAL_CAPACITY << 1];
+        } else if (entries.length == nextEntryIndex << 1) {
+            grow();
+
+            assert entries.length > totalEntries << 1;
+            // Can change if grow is actually compressing.
+            nextEntryIndex = totalEntries;
+        }
+
+        setKey(nextEntryIndex, key);
+        setValue(nextEntryIndex, value);
+        totalEntries++;
+
+        if (hasHashArray()) {
+            // Rehash on collision if hash table is more than three quarters full.
+            boolean rehashOnCollision = (getHashTableSize() < (size() + (size() >> 1)));
+            putHashEntry(key, nextEntryIndex, rehashOnCollision);
+        } else if (totalEntries > getHashThreshold()) {
+            createHash();
+        }
+
+        return null;
+    }
+
+    /**
+     * Number of entries above which a hash table should be constructed.
+     */
+    private int getHashThreshold() {
+        if (strategy == null || strategy == Equivalence.IDENTITY_WITH_SYSTEM_HASHCODE) {
+            return HASH_THRESHOLD_IDENTITY_COMPARE;
+        } else {
+            return HASH_THRESHOLD;
+        }
+    }
+
+    private void grow() {
+        int entriesLength = entries.length;
+        int newSize = (entriesLength >> 1) + Math.max(MIN_CAPACITY_INCREASE, entriesLength >> 2);
+        if (newSize > MAX_ELEMENT_COUNT) {
+            throw new UnsupportedOperationException("map grown too large!");
+        }
+        Object[] newEntries = new Object[newSize << 1];
+        System.arraycopy(entries, 0, newEntries, 0, entriesLength);
+        entries = newEntries;
+        if ((entriesLength < LARGE_HASH_THRESHOLD && newEntries.length >= LARGE_HASH_THRESHOLD) ||
+                        (entriesLength < VERY_LARGE_HASH_THRESHOLD && newEntries.length > VERY_LARGE_HASH_THRESHOLD)) {
+            // Rehash in order to change number of bits reserved for hash indices.
+            createHash();
+        }
+    }
+
+    /**
+     * Compresses the graph if there is a large number of deleted entries and returns the translated
+     * new next index.
+     */
+    private int maybeCompress(int nextIndex) {
+        if (entries.length != INITIAL_CAPACITY << 1 && deletedEntries >= (totalEntries >> 1) + (totalEntries >> 2)) {
+            return compressLarge(nextIndex);
+        }
+        return nextIndex;
+    }
+
+    /**
+     * Compresses the graph and returns the translated new next index.
+     */
+    private int compressLarge(int nextIndex) {
+        int size = INITIAL_CAPACITY;
+        int remaining = totalEntries - deletedEntries;
+
+        while (size <= remaining) {
+            size += Math.max(MIN_CAPACITY_INCREASE, size >> 1);
+        }
+
+        Object[] newEntries = new Object[size << 1];
+        int z = 0;
+        int newNextIndex = remaining;
+        for (int i = 0; i < totalEntries; ++i) {
+            Object key = getKey(i);
+            if (i == nextIndex) {
+                newNextIndex = z;
+            }
+            if (key != null) {
+                newEntries[z << 1] = key;
+                newEntries[(z << 1) + 1] = getValue(i);
+                z++;
+            }
+        }
+
+        this.entries = newEntries;
+        totalEntries = z;
+        deletedEntries = 0;
+        if (z <= getHashThreshold()) {
+            this.hashArray = null;
+        } else {
+            createHash();
+        }
+        return newNextIndex;
+    }
+
+    private int getHashTableSize() {
+        if (entries.length < LARGE_HASH_THRESHOLD) {
+            return hashArray.length;
+        } else if (entries.length < VERY_LARGE_HASH_THRESHOLD) {
+            return hashArray.length >> 1;
+        } else {
+            return hashArray.length >> 2;
+        }
+    }
+
+    private void createHash() {
+        int entryCount = size();
+
+        // Calculate smallest 2^n that is greater number of entries.
+        int size = getHashThreshold();
+        while (size <= entryCount) {
+            size <<= 1;
+        }
+
+        // Give extra size to avoid collisions.
+        size <<= 1;
+
+        if (this.entries.length >= VERY_LARGE_HASH_THRESHOLD) {
+            // Every entry has 4 bytes.
+            size <<= 2;
+        } else if (this.entries.length >= LARGE_HASH_THRESHOLD) {
+            // Every entry has 2 bytes.
+            size <<= 1;
+        } else {
+            // Entries are very small => give extra size to further reduce collisions.
+            size <<= 1;
+        }
+
+        hashArray = new byte[size];
+        for (int i = 0; i < totalEntries; i++) {
+            Object entryKey = getKey(i);
+            if (entryKey != null) {
+                putHashEntry(entryKey, i, false);
+            }
+        }
+    }
+
+    private void putHashEntry(Object key, int entryIndex, boolean rehashOnCollision) {
+        int hashIndex = getHashIndex(key);
+        int oldIndex = getHashArray(hashIndex) - 1;
+        if (oldIndex != -1 && rehashOnCollision) {
+            this.createHash();
+            return;
+        }
+        setHashArray(hashIndex, entryIndex + 1);
+        Object value = getRawValue(entryIndex);
+        if (oldIndex != -1) {
+            assert entryIndex != oldIndex : "this cannot happend and would create an endless collision link cycle";
+            if (value instanceof CollisionLink) {
+                CollisionLink collisionLink = (CollisionLink) value;
+                setRawValue(entryIndex, new CollisionLink(collisionLink.value, oldIndex));
+            } else {
+                setRawValue(entryIndex, new CollisionLink(getRawValue(entryIndex), oldIndex));
+            }
+        } else {
+            if (value instanceof CollisionLink) {
+                CollisionLink collisionLink = (CollisionLink) value;
+                setRawValue(entryIndex, collisionLink.value);
+            }
+        }
+    }
+
+    @Override
+    public int size() {
+        return totalEntries - deletedEntries;
+    }
+
+    @Override
+    public boolean containsKey(K key) {
+        return find(key) != -1;
+    }
+
+    @Override
+    public void clear() {
+        entries = null;
+        hashArray = null;
+        totalEntries = deletedEntries = 0;
+    }
+
+    private boolean hasHashArray() {
+        return hashArray != null;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public V removeKey(K key) {
+        if (key == null) {
+            throw new UnsupportedOperationException("null not supported as key!");
+        }
+        int index;
+        if (hasHashArray()) {
+            index = this.findAndRemoveHash(key);
+        } else {
+            index = this.findLinear(key);
+        }
+
+        if (index != -1) {
+            Object value = getValue(index);
+            remove(index);
+            return (V) value;
+        }
+        return null;
+    }
+
+    /**
+     * Removes the element at the specific index and returns the index of the next element. This can
+     * be a different value if graph compression was triggered.
+     */
+    private int remove(int indexToRemove) {
+        int index = indexToRemove;
+        int entriesAfterIndex = totalEntries - index - 1;
+        int result = index + 1;
+
+        // Without hash array, compress immediately.
+        if (entriesAfterIndex <= COMPRESS_IMMEDIATE_CAPACITY && !hasHashArray()) {
+            while (index < totalEntries - 1) {
+                setKey(index, getKey(index + 1));
+                setRawValue(index, getRawValue(index + 1));
+                index++;
+            }
+            result--;
+        }
+
+        setKey(index, null);
+        setRawValue(index, null);
+        if (index == totalEntries - 1) {
+            // Make sure last element is always non-null.
+            totalEntries--;
+            while (index > 0 && getKey(index - 1) == null) {
+                totalEntries--;
+                deletedEntries--;
+                index--;
+            }
+        } else {
+            deletedEntries++;
+            result = maybeCompress(result);
+        }
+
+        return result;
+    }
+
+    private abstract class SparseMapIterator<E> implements Iterator<E> {
+
+        protected int current;
+
+        @Override
+        public boolean hasNext() {
+            return current < totalEntries;
+        }
+
+        @Override
+        public void remove() {
+            if (hasHashArray()) {
+                EconomicMapImpl.this.findAndRemoveHash(getKey(current - 1));
+            }
+            current = EconomicMapImpl.this.remove(current - 1);
+        }
+    }
+
+    @Override
+    public Iterable<V> getValues() {
+        return new Iterable<V>() {
+            @Override
+            public Iterator<V> iterator() {
+                return new SparseMapIterator<V>() {
+                    @SuppressWarnings("unchecked")
+                    @Override
+                    public V next() {
+                        Object result;
+                        while (true) {
+                            result = getValue(current);
+                            if (result == null && getKey(current) == null) {
+                                // values can be null, double-check if key is also null
+                                current++;
+                            } else {
+                                current++;
+                                break;
+                            }
+                        }
+                        return (V) result;
+                    }
+                };
+            }
+        };
+    }
+
+    @Override
+    public Iterable<K> getKeys() {
+        return this;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return this.size() == 0;
+    }
+
+    @Override
+    public MapCursor<K, V> getEntries() {
+        return new MapCursor<K, V>() {
+            int current = -1;
+
+            @Override
+            public boolean advance() {
+                current++;
+                if (current >= totalEntries) {
+                    return false;
+                } else {
+                    while (EconomicMapImpl.this.getKey(current) == null) {
+                        // Skip over null entries
+                        current++;
+                    }
+                    return true;
+                }
+            }
+
+            @SuppressWarnings("unchecked")
+            @Override
+            public K getKey() {
+                return (K) EconomicMapImpl.this.getKey(current);
+            }
+
+            @SuppressWarnings("unchecked")
+            @Override
+            public V getValue() {
+                return (V) EconomicMapImpl.this.getValue(current);
+            }
+
+            @Override
+            public void remove() {
+                if (hasHashArray()) {
+                    EconomicMapImpl.this.findAndRemoveHash(EconomicMapImpl.this.getKey(current));
+                }
+                current = EconomicMapImpl.this.remove(current) - 1;
+            }
+        };
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
+        for (int i = 0; i < totalEntries; i++) {
+            Object entryKey = getKey(i);
+            if (entryKey != null) {
+                Object newValue = function.apply((K) entryKey, (V) getValue(i));
+                setValue(i, newValue);
+            }
+        }
+    }
+
+    private Object getKey(int index) {
+        return entries[index << 1];
+    }
+
+    private void setKey(int index, Object newValue) {
+        entries[index << 1] = newValue;
+    }
+
+    private void setValue(int index, Object newValue) {
+        Object oldValue = getRawValue(index);
+        if (oldValue instanceof CollisionLink) {
+            CollisionLink collisionLink = (CollisionLink) oldValue;
+            setRawValue(index, new CollisionLink(newValue, collisionLink.next));
+        } else {
+            setRawValue(index, newValue);
+        }
+    }
+
+    private void setRawValue(int index, Object newValue) {
+        entries[(index << 1) + 1] = newValue;
+    }
+
+    private Object getRawValue(int index) {
+        return entries[(index << 1) + 1];
+    }
+
+    private Object getValue(int index) {
+        Object object = getRawValue(index);
+        if (object instanceof CollisionLink) {
+            return ((CollisionLink) object).value;
+        }
+        return object;
+    }
+
+    private final boolean isSet;
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append(isSet ? "set(size=" : "map(size=").append(size()).append(", {");
+        String sep = "";
+        MapCursor<K, V> cursor = getEntries();
+        while (cursor.advance()) {
+            builder.append(sep);
+            if (isSet) {
+                builder.append(cursor.getKey());
+            } else {
+                builder.append("(").append(cursor.getKey()).append(",").append(cursor.getValue()).append(")");
+            }
+            sep = ",";
+        }
+        builder.append("})");
+        return builder.toString();
+    }
+
+    @Override
+    public Iterator<K> iterator() {
+        return new SparseMapIterator<K>() {
+            @SuppressWarnings("unchecked")
+            @Override
+            public K next() {
+                Object result;
+                while ((result = getKey(current++)) == null) {
+                    // skip null entries
+                }
+                return (K) result;
+            }
+        };
+    }
+
+    @Override
+    public boolean contains(K element) {
+        return containsKey(element);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public boolean add(K element) {
+        return put(element, (V) element) == null;
+    }
+
+    @Override
+    public void remove(K element) {
+        removeKey(element);
+    }
+}