eolivelli commented on a change in pull request #118:
URL: https://github.com/apache/commons-io/pull/118#discussion_r462045891
##########
File path: src/main/java/org/apache/commons/io/IOUtils.java
##########
@@ -752,19 +777,46 @@ public static boolean contentEquals(final Reader input1,
final Reader input2)
if (input1 == null ^ input2 == null) {
return false;
}
- final BufferedReader bufferedInput1 = toBufferedReader(input1);
- final BufferedReader bufferedInput2 = toBufferedReader(input2);
- int ch = bufferedInput1.read();
- while (EOF != ch) {
- final int ch2 = bufferedInput2.read();
- if (ch != ch2) {
- return false;
+ char[] charArray1 = new char[CONTENT_EQUALS_CHAR_ARRAY_BUFFER_SIZE];
+ char[] charArray2 = new char[CONTENT_EQUALS_CHAR_ARRAY_BUFFER_SIZE];
+ int nowPos1;
+ int nowPos2;
+ int nowRead1;
+ int nowRead2;
+ while (true) {
+ nowPos1 = 0;
+ nowPos2 = 0;
+ for (int nowCheck = 0; nowCheck <
CONTENT_EQUALS_CHAR_ARRAY_BUFFER_SIZE; nowCheck++) {
+ if (nowPos1 == nowCheck) {
+ do {
+ nowRead1 = input1.read(charArray1, nowPos1,
CONTENT_EQUALS_CHAR_ARRAY_BUFFER_SIZE - nowPos1);
+ } while (nowRead1 == 0);
+ if (nowRead1 == -1) {
+ return nowPos2 == nowCheck && input2.read() == -1;
+ }
+ nowPos1 += nowRead1;
+ }
+ if (nowPos2 == nowCheck) {
+ do {
+ nowRead2 = input2.read(charArray2, nowPos2,
CONTENT_EQUALS_CHAR_ARRAY_BUFFER_SIZE - nowPos2);
+ } while (nowRead2 == 0);
+ if (nowRead2 == -1) {
+ return nowPos1 == nowCheck && input1.read() == -1;
+ }
+ nowPos2 += nowRead2;
+ }
+ if (charArray1[nowCheck] != charArray2[nowCheck]) {
+ return false;
+ }
}
- ch = bufferedInput1.read();
}
+ }
- return bufferedInput2.read() == EOF;
+ private enum LastState {
+ r,
Review comment:
Can you please use UPPERCASE identifiers?
Also, IMHO it is better to give meaningful names or add a minimal
explanation
##########
File path:
src/test/java/org/apache/commons/io/performance/IOUtilsContentEqualsPerformanceTest.java
##########
@@ -0,0 +1,178 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.commons.io.performance;
+
+import org.apache.commons.io.IOUtils;
+import org.openjdk.jmh.annotations.*;
+
+import java.io.*;
+import java.util.concurrent.TimeUnit;
+
+import static org.apache.commons.io.IOUtils.EOF;
+import static org.apache.commons.io.IOUtils.toBufferedReader;
+
+/**
+ * Test to show whether using BitSet for removeAll() methods is faster than
using HashSet.
+ */
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Thread)
+public class IOUtilsContentEqualsPerformanceTest {
+
+ private static final String[] STRINGS = new String[3];
+
+ static {
+ STRINGS[0] = getString0();
+ STRINGS[1] = STRINGS[0] + 'c';
+ STRINGS[2] = STRINGS[0] + 'd';
+ }
+
+ private static final int LOOP = 10;
+
+ @Benchmark
+ public boolean[] testContentEqualsForFileNew() throws IOException {
+ boolean[] res = new boolean[2];
+ for (int i = 0; i < LOOP; i++) {
+ try (InputStream inputStream1 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ InputStream inputStream2 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileNoBOM.xml");
+ Reader inputReader1 = new InputStreamReader(inputStream1);
+ Reader inputReader2 = new InputStreamReader(inputStream2);
+ ) {
+ res[0] = IOUtils.contentEquals(inputReader1, inputReader2);
+ }
+ try (InputStream inputStream1 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ InputStream inputStream2 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ Reader inputReader1 = new InputStreamReader(inputStream1);
+ Reader inputReader2 = new InputStreamReader(inputStream2);
+ ) {
+ res[1] = IOUtils.contentEquals(inputReader1, inputReader2);
+ }
+ }
+ return res;
+ }
+
+ @Benchmark
+ public boolean[] testContentEqualsOld() throws IOException {
+ boolean[] res = new boolean[2];
+ for (int i = 0; i < LOOP; i++) {
+ try (InputStream inputStream1 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ InputStream inputStream2 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileNoBOM.xml");
+ Reader inputReader1 = new InputStreamReader(inputStream1);
+ Reader inputReader2 = new InputStreamReader(inputStream2);
+ ) {
+ res[0] = contentEqualsOld(inputReader1, inputReader2);
+ }
+ try (InputStream inputStream1 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ InputStream inputStream2 =
+
this.getClass().getResourceAsStream("/org/apache/commons/io/testfileBOM.xml");
+ Reader inputReader1 = new InputStreamReader(inputStream1);
+ Reader inputReader2 = new InputStreamReader(inputStream2);
+ ) {
+ res[1] = contentEqualsOld(inputReader1, inputReader2);
+ }
+ }
+ return res;
+ }
+
+ @Benchmark
+ public boolean[] testContentEqualsNew2() throws IOException {
+ boolean[] res = new boolean[9];
+ for (int i = 0; i < 3; i++) {
+ for (int j = 0; j < 3; j++) {
+ try (Reader inputReader1 = new StringReader(STRINGS[i]);
+ Reader inputReader2 = new StringReader(STRINGS[j]);
+ ) {
+ res[i * 3 + j] = IOUtils.contentEquals(inputReader1,
inputReader2);
+ }
+ }
+ }
+ return res;
+ }
+
+ @Benchmark
+ public boolean[] testContentEqualsOld2() throws IOException {
+ boolean[] res = new boolean[9];
+ for (int i = 0; i < 3; i++) {
+ for (int j = 0; j < 3; j++) {
+ try (Reader inputReader1 = new StringReader(STRINGS[i]);
+ Reader inputReader2 = new StringReader(STRINGS[j]);
+ ) {
+ res[i * 3 + j] = contentEqualsOld(inputReader1,
inputReader2);
+ }
+ }
+ }
+ return res;
+ }
+
+ /**
+ * Old version of IOUtils.contentEquals(Reader, Reader)
+ *
+ * Compares the contents of two Readers to determine if they are equal or
+ * not.
+ * <p>
+ * This method buffers the input internally using
+ * <code>BufferedReader</code> if they are not already buffered.
+ * </p>
+ *
+ * @param input1 the first reader
+ * @param input2 the second reader
+ * @return true if the content of the readers are equal or they both don't
+ * exist, false otherwise
+ * @throws NullPointerException if either input is null
+ * @throws IOException if an I/O error occurs
+ * @since 1.1
+ */
+ @SuppressWarnings("resource")
+ public static boolean contentEqualsOld(final Reader input1, final Reader
input2)
+ throws IOException {
+ if (input1 == input2) {
+ return true;
+ }
+ if (input1 == null ^ input2 == null) {
+ return false;
+ }
+ final BufferedReader bufferedInput1 = toBufferedReader(input1);
+ final BufferedReader bufferedInput2 = toBufferedReader(input2);
+
+ int ch = bufferedInput1.read();
+ while (EOF != ch) {
+ final int ch2 = bufferedInput2.read();
+ if (ch != ch2) {
+ return false;
+ }
+ ch = bufferedInput1.read();
+ }
+
+ return bufferedInput2.read() == EOF;
+ }
+
+ public static String getString0() {
+ StringBuilder stringBuilder = new StringBuilder("ab");
+ for (int i = 0; i < 24; i++) {
Review comment:
Did you test with larger strings?
24 looks like a small string
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