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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
/*
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Rhino code, released
* May 6, 1999.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1997-2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Igor Bukanov
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License Version 2 or later (the "GPL"), in which
* case the provisions of the GPL are applicable instead of those above. If
* you wish to allow use of your version of this file only under the terms of
* the GPL and not to allow others to use your version of this file under the
* MPL, indicate your decision by deleting the provisions above and replacing
* them with the notice and other provisions required by the GPL. If you do
* not delete the provisions above, a recipient may use your version of this
* file under either the MPL or the GPL.
*
* ***** END LICENSE BLOCK ***** */
package com.google.javascript.rhino;
import java.io.Serializable;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
/**
* Map to associate non-negative integers to objects or integers.
* The map does not synchronize any of its operation, so either use
* it from a single thread or do own synchronization or perform all mutation
* operations on one thread before passing the map to others.
*
*
*/
public class UintMap implements Serializable
{
static final long serialVersionUID = 4242698212885848444L;
// Map implementation via hashtable,
// follows "The Art of Computer Programming" by Donald E. Knuth
public UintMap() {
this(4);
}
public UintMap(int initialCapacity) {
if (initialCapacity < 0) Kit.codeBug();
// Table grow when number of stored keys >= 3/4 of max capacity
int minimalCapacity = initialCapacity * 4 / 3;
int i;
for (i = 2; (1 << i) < minimalCapacity; ++i) { }
power = i;
assert !(power < 2);
}
public boolean isEmpty() {
return keyCount == 0;
}
public int size() {
return keyCount;
}
public boolean has(int key) {
if (key < 0) Kit.codeBug();
return 0 <= findIndex(key);
}
/**
* Get object value assigned with key.
* @return key object value or null if key is absent
*/
public Object getObject(int key) {
if (key < 0) Kit.codeBug();
if (values != null) {
int index = findIndex(key);
if (0 <= index) {
return values[index];
}
}
return null;
}
/**
* Get integer value assigned with key.
* @return key integer value or defaultValue if key is absent
*/
public int getInt(int key, int defaultValue) {
if (key < 0) Kit.codeBug();
int index = findIndex(key);
if (0 <= index) {
if (ivaluesShift != 0) {
return keys[ivaluesShift + index];
}
return 0;
}
return defaultValue;
}
/**
* Get integer value assigned with key.
* @return key integer value or defaultValue if key does not exist or does
* not have int value
* @throws RuntimeException if key does not exist
*/
public int getExistingInt(int key) {
if (key < 0) Kit.codeBug();
int index = findIndex(key);
if (0 <= index) {
if (ivaluesShift != 0) {
return keys[ivaluesShift + index];
}
return 0;
}
// Key must exist
Kit.codeBug();
return 0;
}
/**
* Set object value of the key.
* If key does not exist, also set its int value to 0.
*/
public void put(int key, Object value) {
if (key < 0) Kit.codeBug();
int index = ensureIndex(key, false);
if (values == null) {
values = new Object[1 << power];
}
values[index] = value;
}
/**
* Set int value of the key.
* If key does not exist, also set its object value to null.
*/
public void put(int key, int value) {
if (key < 0) Kit.codeBug();
int index = ensureIndex(key, true);
if (ivaluesShift == 0) {
int N = 1 << power;
// keys.length can be N * 2 after clear which set ivaluesShift to 0
if (keys.length != N * 2) {
int[] tmp = new int[N * 2];
System.arraycopy(keys, 0, tmp, 0, N);
keys = tmp;
}
ivaluesShift = N;
}
keys[ivaluesShift + index] = value;
}
public void remove(int key) {
if (key < 0) Kit.codeBug();
int index = findIndex(key);
if (0 <= index) {
keys[index] = DELETED;
--keyCount;
// Allow to GC value and make sure that new key with the deleted
// slot shall get proper default values
if (values != null) { values[index] = null; }
if (ivaluesShift != 0) { keys[ivaluesShift + index] = 0; }
}
}
public void clear() {
int N = 1 << power;
if (keys != null) {
for (int i = 0; i != N; ++i) {
keys[i] = EMPTY;
}
if (values != null) {
for (int i = 0; i != N; ++i) {
values[i] = null;
}
}
}
ivaluesShift = 0;
keyCount = 0;
occupiedCount = 0;
}
/** Return array of present keys */
public int[] getKeys() {
int[] keys = this.keys;
int n = keyCount;
int[] result = new int[n];
for (int i = 0; n != 0; ++i) {
int entry = keys[i];
if (entry != EMPTY && entry != DELETED) {
result[--n] = entry;
}
}
return result;
}
private static int tableLookupStep(int fraction, int mask, int power) {
int shift = 32 - 2 * power;
if (shift >= 0) {
return ((fraction >>> shift) & mask) | 1;
}
else {
return (fraction & (mask >>> -shift)) | 1;
}
}
private int findIndex(int key) {
int[] keys = this.keys;
if (keys != null) {
int fraction = key * A;
int index = fraction >>> (32 - power);
int entry = keys[index];
if (entry == key) { return index; }
if (entry != EMPTY) {
// Search in table after first failed attempt
int mask = (1 << power) - 1;
int step = tableLookupStep(fraction, mask, power);
int n = 0;
do {
if (check) {
if (n >= occupiedCount) Kit.codeBug();
++n;
}
index = (index + step) & mask;
entry = keys[index];
if (entry == key) { return index; }
} while (entry != EMPTY);
}
}
return -1;
}
// Insert key that is not present to table without deleted entries
// and enough free space
private int insertNewKey(int key) {
assert occupiedCount == keyCount;
assert keyCount != 1 << power;
int[] keys = this.keys;
int fraction = key * A;
int index = fraction >>> (32 - power);
if (keys[index] != EMPTY) {
int mask = (1 << power) - 1;
int step = tableLookupStep(fraction, mask, power);
int firstIndex = index;
do {
assert keys[index] != DELETED;
index = (index + step) & mask;
assert firstIndex != index;
} while (keys[index] != EMPTY);
}
keys[index] = key;
++occupiedCount;
++keyCount;
return index;
}
private void rehashTable(boolean ensureIntSpace) {
if (keys != null) {
// Check if removing deleted entries would free enough space
if (keyCount * 2 >= occupiedCount) {
// Need to grow: less then half of deleted entries
++power;
}
}
int N = 1 << power;
int[] old = keys;
int oldShift = ivaluesShift;
if (oldShift == 0 && !ensureIntSpace) {
keys = new int[N];
}
else {
ivaluesShift = N; keys = new int[N * 2];
}
for (int i = 0; i != N; ++i) { keys[i] = EMPTY; }
Object[] oldValues = values;
if (oldValues != null) { values = new Object[N]; }
int oldCount = keyCount;
occupiedCount = 0;
if (oldCount != 0) {
keyCount = 0;
for (int i = 0, remaining = oldCount; remaining != 0; ++i) {
int key = old[i];
if (key != EMPTY && key != DELETED) {
int index = insertNewKey(key);
if (oldValues != null) {
values[index] = oldValues[i];
}
if (oldShift != 0) {
keys[ivaluesShift + index] = old[oldShift + i];
}
--remaining;
}
}
}
}
// Ensure key index creating one if necessary
private int ensureIndex(int key, boolean intType) {
int index = -1;
int firstDeleted = -1;
int[] keys = this.keys;
if (keys != null) {
int fraction = key * A;
index = fraction >>> (32 - power);
int entry = keys[index];
if (entry == key) { return index; }
if (entry != EMPTY) {
if (entry == DELETED) { firstDeleted = index; }
// Search in table after first failed attempt
int mask = (1 << power) - 1;
int step = tableLookupStep(fraction, mask, power);
int n = 0;
do {
if (check) {
if (n >= occupiedCount) Kit.codeBug();
++n;
}
index = (index + step) & mask;
entry = keys[index];
if (entry == key) { return index; }
if (entry == DELETED && firstDeleted < 0) {
firstDeleted = index;
}
} while (entry != EMPTY);
}
}
// Inserting of new key
assert (keys == null || keys[index] == EMPTY);
if (firstDeleted >= 0) {
index = firstDeleted;
}
else {
// Need to consume empty entry: check occupation level
if (keys == null || occupiedCount * 4 >= (1 << power) * 3) {
// Too litle unused entries: rehash
rehashTable(intType);
keys = this.keys;
return insertNewKey(key);
}
++occupiedCount;
}
keys[index] = key;
++keyCount;
return index;
}
private void writeObject(ObjectOutputStream out)
throws IOException
{
out.defaultWriteObject();
int count = keyCount;
if (count != 0) {
boolean hasIntValues = (ivaluesShift != 0);
boolean hasObjectValues = (values != null);
out.writeBoolean(hasIntValues);
out.writeBoolean(hasObjectValues);
for (int i = 0; count != 0; ++i) {
int key = keys[i];
if (key != EMPTY && key != DELETED) {
--count;
out.writeInt(key);
if (hasIntValues) {
out.writeInt(keys[ivaluesShift + i]);
}
if (hasObjectValues) {
out.writeObject(values[i]);
}
}
}
}
}
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
int writtenKeyCount = keyCount;
if (writtenKeyCount != 0) {
keyCount = 0;
boolean hasIntValues = in.readBoolean();
boolean hasObjectValues = in.readBoolean();
int N = 1 << power;
if (hasIntValues) {
keys = new int[2 * N];
ivaluesShift = N;
}else {
keys = new int[N];
}
for (int i = 0; i != N; ++i) {
keys[i] = EMPTY;
}
if (hasObjectValues) {
values = new Object[N];
}
for (int i = 0; i != writtenKeyCount; ++i) {
int key = in.readInt();
int index = insertNewKey(key);
if (hasIntValues) {
int ivalue = in.readInt();
keys[ivaluesShift + index] = ivalue;
}
if (hasObjectValues) {
values[index] = in.readObject();
}
}
}
}
// A == golden_ratio * (1 << 32) = ((sqrt(5) - 1) / 2) * (1 << 32)
// See Knuth etc.
private static final int A = 0x9e3779b9;
private static final int EMPTY = -1;
private static final int DELETED = -2;
// Structure of kyes and values arrays (N == 1 << power):
// keys[0 <= i < N]: key value or EMPTY or DELETED mark
// values[0 <= i < N]: value of key at keys[i]
// keys[N <= i < 2N]: int values of keys at keys[i - N]
private transient int[] keys;
private transient Object[] values;
private int power;
private int keyCount;
private transient int occupiedCount; // == keyCount + deleted_count
// If ivaluesShift != 0, keys[ivaluesShift + index] contains integer
// values associated with keys
private transient int ivaluesShift;
// If true, enables consitency checks
private static final boolean check = false;
/* TEST START
public static void main(String[] args) {
if (!check) {
System.err.println("Set check to true and re-run");
throw new RuntimeException("Set check to true and re-run");
}
UintMap map;
map = new UintMap();
testHash(map, 2);
map = new UintMap();
testHash(map, 10 * 1000);
map = new UintMap(30 * 1000);
testHash(map, 10 * 100);
map.clear();
testHash(map, 4);
map = new UintMap(0);
testHash(map, 10 * 100);
}
private static void testHash(UintMap map, int N) {
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
map.put(i, i);
check(i == map.getInt(i, -1));
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
map.put(i, i);
check(i == map.getInt(i, -1));
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
map.put(i, new Integer(i));
check(-1 == map.getInt(i, -1));
Integer obj = (Integer)map.getObject(i);
check(obj != null && i == obj.intValue());
}
check(map.size() == N);
System.out.print("."); System.out.flush();
int[] keys = map.getKeys();
check(keys.length == N);
for (int i = 0; i != N; ++i) {
int key = keys[i];
check(map.has(key));
check(!map.isIntType(key));
check(map.isObjectType(key));
Integer obj = (Integer) map.getObject(key);
check(obj != null && key == obj.intValue());
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
check(-1 == map.getInt(i, -1));
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
map.put(i * i, i);
check(i == map.getInt(i * i, -1));
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
check(i == map.getInt(i * i, -1));
}
System.out.print("."); System.out.flush();
for (int i = 0; i != N; ++i) {
map.put(i * i, new Integer(i));
check(-1 == map.getInt(i * i, -1));
map.remove(i * i);
check(!map.has(i * i));
map.put(i * i, i);
check(map.isIntType(i * i));
check(null == map.getObject(i * i));
map.remove(i * i);
check(!map.isObjectType(i * i));
check(!map.isIntType(i * i));
}
int old_size = map.size();
for (int i = 0; i != N; ++i) {
map.remove(i * i);
check(map.size() == old_size);
}
System.out.print("."); System.out.flush();
map.clear();
check(map.size() == 0);
for (int i = 0; i != N; ++i) {
map.put(i * i, i);
map.put(i * i + 1, new Double(i+0.5));
}
checkSameMaps(map, (UintMap)writeAndRead(map));
System.out.print("."); System.out.flush();
map = new UintMap(0);
checkSameMaps(map, (UintMap)writeAndRead(map));
map = new UintMap(1);
checkSameMaps(map, (UintMap)writeAndRead(map));
map = new UintMap(1000);
checkSameMaps(map, (UintMap)writeAndRead(map));
System.out.print("."); System.out.flush();
map = new UintMap(N / 10);
for (int i = 0; i != N; ++i) {
map.put(2*i+1, i);
}
checkSameMaps(map, (UintMap)writeAndRead(map));
System.out.print("."); System.out.flush();
map = new UintMap(N / 10);
for (int i = 0; i != N; ++i) {
map.put(2*i+1, i);
}
for (int i = 0; i != N / 2; ++i) {
map.remove(2*i+1);
}
checkSameMaps(map, (UintMap)writeAndRead(map));
System.out.print("."); System.out.flush();
map = new UintMap();
for (int i = 0; i != N; ++i) {
map.put(2*i+1, new Double(i + 10));
}
for (int i = 0; i != N / 2; ++i) {
map.remove(2*i+1);
}
checkSameMaps(map, (UintMap)writeAndRead(map));
System.out.println(); System.out.flush();
}
private static void checkSameMaps(UintMap map1, UintMap map2) {
check(map1.size() == map2.size());
int[] keys = map1.getKeys();
check(keys.length == map1.size());
for (int i = 0; i != keys.length; ++i) {
int key = keys[i];
check(map2.has(key));
check(map1.isObjectType(key) == map2.isObjectType(key));
check(map1.isIntType(key) == map2.isIntType(key));
Object o1 = map1.getObject(key);
Object o2 = map2.getObject(key);
if (map1.isObjectType(key)) {
check(o1.equals(o2));
}else {
check(map1.getObject(key) == null);
check(map2.getObject(key) == null);
}
if (map1.isIntType(key)) {
check(map1.getExistingInt(key) == map2.getExistingInt(key));
}else {
check(map1.getInt(key, -10) == -10);
check(map1.getInt(key, -11) == -11);
check(map2.getInt(key, -10) == -10);
check(map2.getInt(key, -11) == -11);
}
}
}
private static void check(boolean condition) {
if (!condition) Kit.codeBug();
}
private static Object writeAndRead(Object obj) {
try {
java.io.ByteArrayOutputStream
bos = new java.io.ByteArrayOutputStream();
java.io.ObjectOutputStream
out = new java.io.ObjectOutputStream(bos);
out.writeObject(obj);
out.close();
byte[] data = bos.toByteArray();
java.io.ByteArrayInputStream
bis = new java.io.ByteArrayInputStream(data);
java.io.ObjectInputStream
in = new java.io.ObjectInputStream(bis);
Object result = in.readObject();
in.close();
return result;
}catch (Exception ex) {
ex.printStackTrace();
throw new RuntimeException("Unexpected");
}
}
// TEST END */
}