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garydgregorygarydgregory
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Speedup CharSequenceUtils.toCharArray(CharSequence)
- StringBuilder Performance Gain: 160-205% improvement (2-3x faster) - StringBuffer Performance Gain: 300-4,250% improvement (4-44x faster) - String: ~1-2% improvement (essentially identical) - This change was suggested by Claude Sonnet 4.5
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‎src/changes/changes.xml‎

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@@ -81,6 +81,9 @@ The <action> type attribute can be add,update,fix,remove.
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<action issue="LANG-1803" type="fix" dev="ggregory" due-to="IcoreE">Fix incorrect method invocation in ObjectUtilsTest and Javadoc reference in RandomStringUtils.</action>
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<action issue="LANG-1695" type="fix" dev="ggregory" due-to="Guillaume Nodet, Harshit Goel, Gary Gregory">Allow trailing decimal point in NumberUtils.isParsable #1531.</action>
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<action issue="LANG-1804" type="fix" dev="ggregory" due-to="IcoreE, Gary Gregory">Fix CharSet#getInstance returns null instead of EMPTY when input setStrs is null #1530.</action>
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<action type="fix" dev="ggregory" due-to="Gary Gregory">Speedup CharSequenceUtils.toCharArray(CharSequence) for StringBuilder input: 160-205% improvement (2-3x faster), see CharSequenceUtilsBenchmark.</action>
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<action type="fix" dev="ggregory" due-to="Gary Gregory">Speedup CharSequenceUtils.toCharArray(CharSequence) for StringBuffer input: 300-4,250% improvement (4-44x faster), see CharSequenceUtilsBenchmark.</action>
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<action type="fix" dev="ggregory" due-to="Gary Gregory">Speedup CharSequenceUtils.toCharArray(CharSequence) for String input: ~1-2% improvement (essentially identical).</action>
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<!-- ADD -->
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<!-- UPDATE -->
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<action type="update" dev="ggregory" due-to="Gary Gregory, Dependabot">Bump org.apache.commons:commons-parent from 92 to 93 #1498.</action>

‎src/main/java/org/apache/commons/lang3/CharSequenceUtils.java‎

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@@ -70,7 +70,7 @@ static int indexOf(final CharSequence cs, final CharSequence searchChar, final i
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// return cs.toString().indexOf(searchChar.toString(), start);
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// }
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}
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/**
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* Returns the index within {@code cs} of the first occurrence of the specified character, starting the search at the specified index.
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* <p>
@@ -371,6 +371,16 @@ public static char[] toCharArray(final CharSequence source) {
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if (source instanceof String) {
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return ((String) source).toCharArray();
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}
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if (source instanceof StringBuilder) {
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final char[] array = new char[len];
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((StringBuilder) source).getChars(0, len, array, 0);
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return array;
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}
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if (source instanceof StringBuffer) {
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final char[] array = new char[len];
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((StringBuffer) source).getChars(0, len, array, 0);
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return array;
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}
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final char[] array = new char[len];
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for (int i = 0; i < len; i++) {
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array[i] = source.charAt(i);

‎src/test/java/org/apache/commons/lang3/CharSequenceUtilsBenchmark.java‎

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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.lang3;
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import java.util.concurrent.TimeUnit;
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import org.openjdk.jmh.annotations.Benchmark;
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import org.openjdk.jmh.annotations.BenchmarkMode;
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import org.openjdk.jmh.annotations.Fork;
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import org.openjdk.jmh.annotations.Level;
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import org.openjdk.jmh.annotations.Measurement;
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import org.openjdk.jmh.annotations.Mode;
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import org.openjdk.jmh.annotations.OutputTimeUnit;
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import org.openjdk.jmh.annotations.Param;
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import org.openjdk.jmh.annotations.Scope;
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import org.openjdk.jmh.annotations.Setup;
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import org.openjdk.jmh.annotations.State;
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import org.openjdk.jmh.annotations.Warmup;
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/**
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* Benchmark comparing the old and new implementations of CharSequenceUtils methods.
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*
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* <p>
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* Run with:
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* </p>
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*
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* <pre>
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* mvn -P benchmark clean test -Dbenchmark=org.apache.commons.lang3.CharSequenceUtilsBenchmark
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* </pre>
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* <p>
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* Results:
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* </p>
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*
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* <pre>
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Benchmark (charSequenceType) (length) Mode Cnt Score Error Units
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent String 10 avgt 5 1.626 ± 0.011 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent String 50 avgt 5 2.741 ± 0.029 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent String 100 avgt 5 4.235 ± 0.038 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent String 500 avgt 5 17.713 ± 0.273 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent String 1000 avgt 5 34.692 ± 1.752 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuilder 10 avgt 5 1.963 ± 0.047 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuilder 50 avgt 5 4.085 ± 0.042 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuilder 100 avgt 5 5.978 ± 0.177 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuilder 500 avgt 5 25.616 ± 1.621 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuilder 1000 avgt 5 53.749 ± 0.420 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuffer 10 avgt 5 7.239 ± 0.149 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuffer 50 avgt 5 9.061 ± 0.187 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuffer 100 avgt 5 10.281 ± 0.055 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuffer 500 avgt 5 29.647 ± 0.420 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayCurrent StringBuffer 1000 avgt 5 56.203 ± 0.505 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew String 10 avgt 5 1.657 ± 0.030 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew String 50 avgt 5 2.771 ± 0.094 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew String 100 avgt 5 4.281 ± 0.036 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew String 500 avgt 5 17.744 ± 0.091 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew String 1000 avgt 5 34.224 ± 0.251 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuilder 10 avgt 5 1.962 ± 0.128 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuilder 50 avgt 5 4.101 ± 0.035 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuilder 100 avgt 5 5.984 ± 0.062 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuilder 500 avgt 5 25.448 ± 0.152 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuilder 1000 avgt 5 54.531 ± 0.559 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuffer 10 avgt 5 7.260 ± 0.175 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuffer 50 avgt 5 8.537 ± 0.101 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuffer 100 avgt 5 10.502 ± 0.143 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuffer 500 avgt 5 29.584 ± 0.339 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayNew StringBuffer 1000 avgt 5 56.751 ± 0.983 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld String 10 avgt 5 1.656 ± 0.231 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld String 50 avgt 5 2.770 ± 0.222 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld String 100 avgt 5 4.298 ± 0.198 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld String 500 avgt 5 18.023 ± 0.203 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld String 1000 avgt 5 35.053 ± 1.467 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuilder 10 avgt 5 3.164 ± 0.062 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuilder 50 avgt 5 8.907 ± 0.185 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuilder 100 avgt 5 15.801 ± 0.104 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuilder 500 avgt 5 77.203 ± 0.460 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuilder 1000 avgt 5 164.064 ± 2.506 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuffer 10 avgt 5 28.981 ± 0.307 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuffer 50 avgt 5 126.285 ± 1.688 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuffer 100 avgt 5 250.584 ± 5.639 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuffer 500 avgt 5 1231.478 ± 51.296 ns/op
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CharSequenceUtilsBenchmark.benchmarkToCharArrayOld StringBuffer 1000 avgt 5 2453.553 ± 54.004 ns/op
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* </pre>
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*
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*/
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@State(Scope.Thread)
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@Fork(1)
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@Warmup(iterations = 3, time = 1)
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@Measurement(iterations = 5, time = 1)
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public class CharSequenceUtilsBenchmark {
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/**
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* New optimized implementation of toCharArray.
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*/
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public static char[] toCharArrayNew(final CharSequence source) {
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final int len = StringUtils.length(source);
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if (len == 0) {
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return ArrayUtils.EMPTY_CHAR_ARRAY;
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}
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if (source instanceof String) {
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return ((String) source).toCharArray();
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}
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// NEW: Uses bulk getChars() for StringBuilder/StringBuffer
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if (source instanceof StringBuilder) {
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final char[] array = new char[len];
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((StringBuilder) source).getChars(0, len, array, 0);
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return array;
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}
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if (source instanceof StringBuffer) {
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final char[] array = new char[len];
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((StringBuffer) source).getChars(0, len, array, 0);
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return array;
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}
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final char[] array = new char[len];
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for (int i = 0; i < len; i++) {
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array[i] = source.charAt(i);
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}
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return array;
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}
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/**
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* Old implementation of toCharArray.
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*/
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public static char[] toCharArrayOld(final CharSequence source) {
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final int len = StringUtils.length(source);
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if (len == 0) {
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return ArrayUtils.EMPTY_CHAR_ARRAY;
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}
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if (source instanceof String) {
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return ((String) source).toCharArray();
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}
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// OLD: Always uses charAt() loop, even for StringBuilder/StringBuffer
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final char[] array = new char[len];
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for (int i = 0; i < len; i++) {
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array[i] = source.charAt(i);
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}
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return array;
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}
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@Param({ "10", "50", "100", "500", "1000" })
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public int length;
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@Param({ "String", "StringBuilder", "StringBuffer" })
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public String charSequenceType;
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private CharSequence testSequence;
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@Benchmark
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public char[] benchmarkToCharArrayCurrent() {
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return CharSequenceUtils.toCharArray(testSequence);
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}
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@Benchmark
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public char[] benchmarkToCharArrayNew() {
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return toCharArrayNew(testSequence);
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}
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@Benchmark
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public char[] benchmarkToCharArrayOld() {
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return toCharArrayOld(testSequence);
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}
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@Setup(Level.Trial)
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public void setup() {
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final StringBuilder sb = new StringBuilder(length);
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for (int i = 0; i < length; i++) {
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sb.append((char) ('a' + i % 26));
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}
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final String content = sb.toString();
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switch (charSequenceType) {
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case "String":
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testSequence = content;
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break;
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case "StringBuilder":
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testSequence = new StringBuilder(content);
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break;
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case "StringBuffer":
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testSequence = new StringBuffer(content);
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break;
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}
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}
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}

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