/*
* Copyright 2008 Google Inc.
*
* 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.google.gwt.lang;
import com.google.gwt.lang.BigLongLibBase.BigLong;
/**
* Implements a Java <code>long</code> in a way that can be translated to JavaScript.
*/
public class LongLib {
/**
* Abstraction for long emulation. The emulation could be done using FastLong if the number is
* small enough or BigLong if the number is big. Note that, the class here is just a place holder
* and would normally extend JavaScriptObject if there wasn't a JVM mode.
*/
static class LongEmul {
SmallLong small;
BigLong big;
}
/**
* A LongEmul represented as double number.
*/
static class SmallLong {
double d;
}
/**
* Allow standalone Java tests such as LongLibTest/LongLibJreTest to run this
* code.
*/
protected static boolean RUN_IN_JVM = false;
public static LongEmul add(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) + asDouble(b);
if (isSafeIntegerRange(result)) {
return createSmallLongEmul(result);
}
}
return createLongEmul(BigLongLib.add(toBigLong(a), toBigLong(b)));
}
public static LongEmul sub(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) - asDouble(b);
if (isSafeIntegerRange(result)) {
return createSmallLongEmul(result);
}
}
return createLongEmul(BigLongLib.sub(toBigLong(a), toBigLong(b)));
}
public static LongEmul neg(LongEmul a) {
// TODO: add test for max neg number
if (isSmallLong(a)) {
double result = 0 - asDouble(a);
if (!Double.isNaN(result)) {
return createSmallLongEmul(result);
}
}
return createLongEmul(BigLongLib.neg(asBigLong(a)));
}
public static boolean gt(LongEmul a, LongEmul b) {
return compare(a, b) > 0;
}
public static boolean gte(LongEmul a, LongEmul b) {
return compare(a, b) >= 0;
}
public static boolean lt(LongEmul a, LongEmul b) {
return compare(a, b) < 0;
}
public static boolean lte(LongEmul a, LongEmul b) {
return compare(a, b) <= 0;
}
public static boolean eq(LongEmul a, LongEmul b) {
return compare(a, b) == 0;
}
public static boolean neq(LongEmul a, LongEmul b) {
return compare(a, b) != 0;
}
// VisibleForTesting
static double compare(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) - asDouble(b);
if (!Double.isNaN(result)) {
return result;
}
}
return BigLongLib.compare(toBigLong(a), toBigLong(b));
}
public static LongEmul div(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) / asDouble(b);
if (isSafeIntegerRange(result)) {
return createSmallLongEmul(truncate(result));
}
}
return createLongEmul(BigLongLib.div(toBigLong(a), toBigLong(b)));
}
public static LongEmul mod(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) % asDouble(b);
if (isSafeIntegerRange(result)) {
return createSmallLongEmul(result);
}
}
return createLongEmul(BigLongLib.mod(toBigLong(a), toBigLong(b)));
}
public static LongEmul mul(LongEmul a, LongEmul b) {
if (isSmallLong(a) && isSmallLong(b)) {
double result = asDouble(a) * asDouble(b);
if (isSafeIntegerRange(result)) {
return createSmallLongEmul(result);
}
}
return createLongEmul(BigLongLib.mul(toBigLong(a), toBigLong(b)));
}
public static LongEmul not(LongEmul a) {
return createLongEmul(BigLongLib.not(toBigLong(a)));
}
public static LongEmul and(LongEmul a, LongEmul b) {
return createLongEmul(BigLongLib.and(toBigLong(a), toBigLong(b)));
}
public static LongEmul or(LongEmul a, LongEmul b) {
return createLongEmul(BigLongLib.or(toBigLong(a), toBigLong(b)));
}
public static LongEmul xor(LongEmul a, LongEmul b) {
return createLongEmul(BigLongLib.xor(toBigLong(a), toBigLong(b)));
}
public static LongEmul shl(LongEmul a, int n) {
return createLongEmul(BigLongLib.shl(toBigLong(a), n));
}
public static LongEmul shr(LongEmul a, int n) {
return createLongEmul(BigLongLib.shr(toBigLong(a), n));
}
public static LongEmul shru(LongEmul a, int n) {
return createLongEmul(BigLongLib.shru(toBigLong(a), n));
}
public static LongEmul fromDouble(double value) {
if (isSafeIntegerRange(value)) {
return createSmallLongEmul(truncate(value));
}
return createLongEmul(BigLongLib.fromDouble(value));
}
public static double toDouble(LongEmul a) {
if (isSmallLong(a)) {
double d = asDouble(a);
// We need to kill negative zero because that could never happen in long but our double based
// representation may result with that.
return d == -0.0 ? 0 : d;
}
return BigLongLib.toDouble(asBigLong(a));
}
public static LongEmul fromInt(int value) {
return createSmallLongEmul(value);
}
public static int toInt(LongEmul a) {
if (isSmallLong(a)) {
return coerceToInt(asDouble(a));
}
return BigLongLib.toInt(asBigLong(a));
}
public static String toString(LongEmul a) {
if (isSmallLong(a)) {
return toString(asDouble(a));
}
return BigLongLib.toString(asBigLong(a));
}
// Called by compiler to generate constants.
public static long[] getAsLongArray(long l) {
if (isSafeIntegerRange(l)) {
return new long[] {l};
}
return BigLongLib.getAsLongArray(l);
}
// TODO(goktug): Safe integer range could potentially increased update up to 53 bits.
private static boolean isSafeIntegerRange(double value) {
return -BigLongLibBase.TWO_PWR_44_DBL < value && value < BigLongLibBase.TWO_PWR_44_DBL;
}
private static double truncate(double value) {
// Same as Math.trunc() but not available everywhere.
return value < 0 ? Math.ceil(value) : Math.floor(value);
}
private static int coerceToInt(double value) {
if (LongLib.RUN_IN_JVM) {
return (int) (long) value;
}
return coerceToInt0(value);
}
private static native int coerceToInt0(double value)/*-{
return value | 0;
}-*/;
private static String toString(double value) {
if (LongLib.RUN_IN_JVM) {
return String.valueOf((long) value);
}
return String.valueOf(value);
}
private static double asDouble(LongEmul value) {
return asDouble(asSmallLong(value));
}
private static SmallLong asSmallLong(LongEmul value) {
if (LongLib.RUN_IN_JVM) {
return value.small;
}
return asSmallLong0(value);
}
private static native SmallLong asSmallLong0(LongEmul value)/*-{
return value;
}-*/;
private static double asDouble(SmallLong value) {
if (LongLib.RUN_IN_JVM) {
return value == null ? Double.NaN : value.d;
}
return asDouble0(value);
}
private static native double asDouble0(SmallLong value)/*-{
return value;
}-*/;
private static boolean isSmallLong(LongEmul value) {
if (LongLib.RUN_IN_JVM) {
return value.small != null;
}
return isSmallLong0(value);
}
private static native boolean isSmallLong0(LongEmul value)/*-{
return typeof(value) === 'number';
}-*/;
// Visible for testing
static BigLong asBigLong(LongEmul value) {
if (LongLib.RUN_IN_JVM) {
return value.big;
}
return asBigLong0(value);
}
private static native BigLong asBigLong0(LongEmul value)/*-{
return value;
}-*/;
private static BigLong toBigLong(LongEmul value) {
return isSmallLong(value) ? toBigLong(asSmallLong(value)) : asBigLong(value);
}
private static BigLong toBigLong(SmallLong longValue) {
double value = asDouble(longValue);
int a3 = 0;
if (value < 0) {
// Convert to a positive number that will have the exact same first 44 bits
value += BigLongLibBase.TWO_PWR_44_DBL;
a3 = BigLongLib.MASK_2;
}
int a1 = (int) (value / BigLongLibBase.TWO_PWR_22_DBL);
int a0 = (int) (value - a1 * BigLongLibBase.TWO_PWR_22_DBL);
return BigLongLibBase.create(a0, a1, a3);
}
private static LongEmul createSmallLongEmul(double value) {
if (LongLib.RUN_IN_JVM) {
SmallLong small = new SmallLong();
small.d = value;
LongEmul emul = new LongEmul();
emul.small = small;
return emul;
}
return createSmallLongEmul0(value);
}
private static native LongEmul createSmallLongEmul0(double value)/*-{
return value;
}-*/;
private static LongEmul createLongEmul(BigLong big) {
int a2 = BigLongLibBase.getH(big);
if (a2 == 0) {
return createSmallLongEmul(
BigLongLibBase.getL(big) + BigLongLibBase.getM(big) * BigLongLibBase.TWO_PWR_22_DBL);
}
if (a2 == BigLongLibBase.MASK_2) {
return createSmallLongEmul(BigLongLibBase.getL(big)
+ BigLongLibBase.getM(big) * BigLongLibBase.TWO_PWR_22_DBL
- BigLongLib.TWO_PWR_44_DBL);
}
return createBigLongEmul(big);
}
private static LongEmul createBigLongEmul(BigLong big) {
if (LongLib.RUN_IN_JVM) {
LongEmul emul = new LongEmul();
emul.big = big;
return emul;
}
return createBigLongEmul0(big);
}
private static native LongEmul createBigLongEmul0(BigLong value)/*-{
return value;
}-*/;
// VisibleForTesting
static LongEmul copy(LongEmul value) {
if (isSmallLong(value)) {
return createSmallLongEmul(asDouble(value));
} else {
return createBigLongEmul(BigLongLibBase.create(asBigLong(value)));
}
}
/**
* Not instantiable.
*/
private LongLib() {
}
}