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Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* 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 com.oracle.truffle.object;
import java.util.Arrays;
import java.util.Map;
import java.util.function.Consumer;
abstract class TrieNode> {
protected static final int HASH_SHIFT = 5; // t
protected static final int HASH_RANGE = 32; // 2**t
protected static final int HASH_MASK = HASH_RANGE - 1;
private static final BitmapNode EMPTY_NODE = new BitmapNode<>();
@SuppressWarnings("unchecked")
static > TrieNode empty() {
return (TrieNode) EMPTY_NODE;
}
final E find(K key, int hash) {
assert key != null && hash(key) == hash;
return find(key, hash, 0);
}
final TrieNode put(K key, int hash, E entry) {
assert key != null && hash(key) == hash && key(entry).equals(key);
return put(key, hash, entry, 0);
}
final TrieNode remove(K key, int hash) {
assert key != null && hash(key) == hash;
return remove(key, hash, 0);
}
abstract E find(K key, int hash, int shift);
abstract TrieNode put(K key, int hash, E entry, int shift);
abstract TrieNode remove(K key, int hash, int shift);
final K key(E entry) {
return entry.getKey();
}
final int hash(K key) {
return key.hashCode();
}
final boolean isEmpty() {
return this == empty();
}
static int pos(int hash, int shift) {
return (hash >>> shift) & HASH_MASK;
}
static int bit(int pos) {
return 1 << pos;
}
static int bit(int hash, int shift) {
return bit(pos(hash, shift));
}
static T[] copyAndSet(T[] original, int index, T newValue) {
T[] copy = Arrays.copyOf(original, original.length);
copy[index] = newValue;
return copy;
}
@SuppressWarnings("unchecked")
static T[] copyAndRemove(T[] original, int index) {
int newLength = original.length - 1;
T[] copy = (T[]) new Object[newLength];
System.arraycopy(original, 0, copy, 0, index);
System.arraycopy(original, index + 1, copy, index, newLength - index);
return copy;
}
@SuppressWarnings("unchecked")
static T[] copyAndInsert(T[] original, int index, T element) {
int newLength = original.length + 1;
T[] copy = (T[]) new Object[newLength];
System.arraycopy(original, 0, copy, 0, index);
copy[index] = element;
System.arraycopy(original, index, copy, index + 1, original.length - index);
return copy;
}
static T[] copyAndAppend(T[] original, T element) {
T[] newArray = Arrays.copyOf(original, original.length + 1);
newArray[original.length] = element;
return newArray;
}
abstract Object[] entries();
final int count() {
int count = 0;
for (Object entry : entries()) {
if (entry == null) {
continue;
} else if (entry instanceof TrieNode) {
count += ((TrieNode) entry).count();
} else {
count += 1;
}
}
return count;
}
@SuppressWarnings("unchecked")
final void forEachEntry(Consumer consumer) {
for (Object entry : entries()) {
if (entry == null) {
continue;
} else if (entry instanceof TrieNode) {
((TrieNode) entry).forEachEntry(consumer);
} else {
consumer.accept((E) entry);
}
}
}
final boolean verify(int shift) {
forEachEntry(new Consumer() {
public void accept(E e) {
K k = key(e);
assert find(k, hash(k), shift) == e : k;
}
});
return true;
}
@Override
public String toString() {
return toStringIndent(0);
}
private String toStringIndent(int indent) {
StringBuilder sb = new StringBuilder(getClass().getSimpleName());
sb.append("[");
Object[] entries = entries();
if (entries.length > 0) {
for (Object entry : entries) {
if (entry == null) {
continue;
}
sb.append("\n");
for (int i = 0; i <= indent; i++) {
sb.append(" ");
}
if (entry instanceof TrieNode) {
sb.append(((TrieNode) entry).toStringIndent(indent + 1));
} else {
sb.append(entry);
}
}
sb.append("\n");
for (int i = 0; i < indent; i++) {
sb.append(" ");
}
}
sb.append("]");
return sb.toString();
}
final TrieNode combine(K key1, int hash1, E entry1, K key2, int hash2, E entry2, int shift) {
assert !key1.equals(key2);
if (hash1 != hash2) {
int pos1 = pos(hash1, shift);
int pos2 = pos(hash2, shift);
if (pos1 != pos2) {
int bitmap = bit(pos1) | bit(pos2);
if (pos1 < pos2) {
return new BitmapNode<>(bitmap, new Object[]{entry1, entry2});
} else {
return new BitmapNode<>(bitmap, new Object[]{entry2, entry1});
}
} else {
int bitmap = bit(pos1);
return new BitmapNode<>(bitmap, new Object[]{combine(key1, hash1, entry1, key2, hash2, entry2, shift + HASH_SHIFT)});
}
} else {
return new HashCollisionNode<>(hash1, new Object[]{entry1, entry2});
}
}
static class BitmapNode> extends TrieNode {
private final int bitmap;
private final Object[] entries;
BitmapNode() {
this.bitmap = 0;
this.entries = new Object[0];
}
BitmapNode(int bitmap, Object[] entries) {
this.bitmap = bitmap;
this.entries = entries;
assert Integer.bitCount(bitmap) == entries.length;
}
private int index(int bit) {
return Integer.bitCount(bitmap & (bit - 1));
}
@SuppressWarnings("unchecked")
@Override
E find(K key, int hash, int shift) {
int bit = bit(hash, shift);
if ((bitmap & bit) != 0) {
int index = index(bit);
Object entry = entries[index];
assert entry != null;
if (entry instanceof TrieNode) {
return ((TrieNode) entry).find(key, hash, shift + HASH_SHIFT);
} else {
E e = (E) entry;
K k = key(e);
if (k.equals(key)) {
return e;
} else {
return null;
}
}
} else {
return null;
}
}
@SuppressWarnings("unchecked")
@Override
TrieNode put(K key, int hash, E entry, int shift) {
int bit = bit(hash, shift);
int index = index(bit);
if ((bitmap & bit) != 0) {
Object nodeOrEntry = entries[index];
assert nodeOrEntry != null;
if (nodeOrEntry instanceof TrieNode) {
TrieNode newNode = ((TrieNode) nodeOrEntry).put(key, hash, entry, shift + HASH_SHIFT);
if (newNode == nodeOrEntry) {
return this;
} else {
assert newNode != null;
return new BitmapNode<>(bitmap, copyAndSet(entries, index, newNode));
}
} else {
E e = (E) nodeOrEntry;
K k = key(e);
if (k.equals(key)) {
return new BitmapNode<>(bitmap, copyAndSet(entries, index, entry));
} else {
int h = hash(k);
assert bit(h, shift) == bit(hash, shift);
TrieNode newNode = combine(k, h, e, key, hash, entry, shift + HASH_SHIFT);
return new BitmapNode<>(bitmap, copyAndSet(entries, index, newNode));
}
}
} else {
Object[] newArray = copyAndInsert(entries, index, entry);
return new BitmapNode<>(bitmap | bit, newArray);
}
}
@SuppressWarnings("unchecked")
@Override
TrieNode remove(K key, int hash, int shift) {
int bit = bit(hash, shift);
if ((bitmap & bit) != 0) {
int index = index(bit);
Object entry = entries[index];
assert entry != null;
if (entry instanceof TrieNode) {
TrieNode newNode = ((TrieNode) entry).remove(key, hash, shift + HASH_SHIFT);
if (newNode == entry) {
return this;
} else if (!newNode.isEmpty()) {
return new BitmapNode<>(bitmap, copyAndSet(entries, index, collapseSingletonNode(newNode)));
} else {
return removeBitAndIndex(bit, index);
}
} else {
E e = (E) entry;
K k = key(e);
if (k.equals(key)) {
return removeBitAndIndex(bit, index);
} else {
return this;
}
}
} else {
return this;
}
}
private TrieNode removeBitAndIndex(int bit, int index) {
if (entries.length > 1) {
return new BitmapNode<>(bitmap & ~bit, copyAndRemove(entries, index));
} else {
return empty();
}
}
private Object collapseSingletonNode(TrieNode node) {
assert !node.isEmpty();
// remove may return a single-entry node, collapse it into just the entry
if (node instanceof BitmapNode) {
BitmapNode bitmapNode = (BitmapNode) node;
if (bitmapNode.entries.length == 1 && !(bitmapNode.entries[0] instanceof TrieNode)) {
return bitmapNode.entries[0];
}
}
return node;
}
@Override
Object[] entries() {
return entries;
}
}
static class HashCollisionNode> extends TrieNode {
private final int hashcode;
private final Object[] entries;
HashCollisionNode(int hash, Object[] entries) {
this.hashcode = hash;
this.entries = entries;
assert entries.length >= 2;
}
@SuppressWarnings("unchecked")
private int findIndex(K key) {
for (int i = 0; i < entries.length; i++) {
E entry = (E) entries[i];
if (key.equals(key(entry))) {
return i;
}
}
return -1;
}
@SuppressWarnings("unchecked")
@Override
E find(K key, int hash, int shift) {
int index = findIndex(key);
if (index < 0) {
return null;
} else {
E entry = (E) entries[index];
assert entry != null && key(entry).equals(key);
return entry;
}
}
@SuppressWarnings("unchecked")
@Override
TrieNode put(K key, int hash, E entry, int shift) {
if (hash == this.hashcode) {
int index = findIndex(key);
if (index < 0) {
return new HashCollisionNode<>(hash, copyAndAppend(entries, entry));
} else {
E e = (E) entries[index];
assert e != null && key(e).equals(key);
if (e.equals(entry)) {
return this;
} else {
return new HashCollisionNode<>(hash, copyAndSet(entries, index, entry));
}
}
} else {
return new BitmapNode(bit(this.hashcode, shift), new Object[]{this}).put(key, hash, entry, shift);
}
}
@SuppressWarnings("unchecked")
@Override
TrieNode remove(K key, int hash, int shift) {
int index = findIndex(key);
if (index < 0) {
return this;
} else {
assert entries[index] != null && key((E) entries[index]).equals(key);
assert entries.length >= 2;
if (entries.length == 2) {
return new BitmapNode<>(bit(this.hashcode, shift), copyAndRemove(entries, index));
} else {
return new HashCollisionNode<>(hash, copyAndRemove(entries, index));
}
}
}
@Override
Object[] entries() {
return entries;
}
}
}
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