This makes LongLib.toString faster by only dividing once each time through the loop
instead of twice. Also, this patch includes the class LongBenchmark that was used
to verify the speed improvement.
Review by: fabbot, scottb
git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@3084 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/super/com/google/gwt/lang/LongLib.java b/dev/core/super/com/google/gwt/lang/LongLib.java
index 5f0f3f2..4d86ba6 100644
--- a/dev/core/super/com/google/gwt/lang/LongLib.java
+++ b/dev/core/super/com/google/gwt/lang/LongLib.java
@@ -453,14 +453,16 @@
while (!isZero(rem)) {
// Do several digits each time through the loop, so as to
// minimize the calls to the very expensive emulated div.
- final int divByZeroes = 9;
- final int divBy = 1000000000;
+ final int tenPowerZeroes = 9;
+ final int tenPower = 1000000000;
+ double[] tenPowerLong = fromInt(tenPower);
- String digits = "" + toInt(mod(rem, fromInt(divBy)));
- rem = div(rem, fromInt(divBy));
+ final double[] remDivTenPower = div(rem, tenPowerLong);
+ String digits = "" + toInt(sub(rem, mul(remDivTenPower, tenPowerLong)));
+ rem = remDivTenPower;
if (!isZero(rem)) {
- int zeroesNeeded = divByZeroes - digits.length();
+ int zeroesNeeded = tenPowerZeroes - digits.length();
for (; zeroesNeeded > 0; zeroesNeeded--) {
digits = "0" + digits;
}
diff --git a/user/test/com/google/gwt/lang/LongBenchmark.java b/user/test/com/google/gwt/lang/LongBenchmark.java
new file mode 100644
index 0000000..5c502ea
--- /dev/null
+++ b/user/test/com/google/gwt/lang/LongBenchmark.java
@@ -0,0 +1,87 @@
+/*
+ * 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.benchmarks.client.Benchmark;
+import com.google.gwt.benchmarks.client.IntRange;
+import com.google.gwt.benchmarks.client.Operator;
+import com.google.gwt.benchmarks.client.RangeField;
+
+/**
+ * Benchmark for operations on <code>long</code>.
+ */
+public class LongBenchmark extends Benchmark {
+ /**
+ * Which implementations can be benchmarked. ALT is present for benchmarking
+ * alternative implementations against the standard one.
+ */
+ enum LongKind {
+ ALT, STANDARD
+ }
+
+ protected final IntRange incrementRange = new IntRange(0, 62, Operator.ADD, 1);
+ protected final LongKind[] toStringKinds = new LongKind[] {LongKind.STANDARD};
+ protected final IntRange toStringRange = new IntRange(0, 62, Operator.ADD, 1);
+
+ /**
+ * This field is used as a target of assignments that should not be pruned.
+ */
+ @SuppressWarnings("unused")
+ private volatile long volatileLong;
+
+ /**
+ * This field is used as a target of assignments that should not be pruned.
+ */
+ @SuppressWarnings("unused")
+ private volatile String volatileString;
+
+ @Override
+ public String getModuleName() {
+ return "com.google.gwt.emultest.EmulSuite";
+ }
+
+ public void testIncrement() {
+ }
+
+ public void testIncrement(@RangeField("incrementRange")
+ Integer xPwr) {
+ long x = 1L << xPwr;
+ for (int i = 1000; i != 0; i--) {
+ x++;
+ x++;
+ x++;
+ }
+ volatileLong = x;
+ }
+
+ public void testToString() {
+ }
+
+ public void testToString(@RangeField("toStringRange")
+ Integer xPwr, @RangeField("toStringKinds")
+ LongKind longKind) {
+ long x = 1L << xPwr;
+ switch (longKind) {
+ case STANDARD:
+ for (int i = 100; i != 0; i--) {
+ volatileString = String.valueOf(x);
+ volatileString = String.valueOf(x);
+ volatileString = String.valueOf(x);
+ }
+ break;
+ }
+ }
+}
