/*
* Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
/* @test
* @bug 4806007
* @summary Checks for vague exceptions from writeUTF/readUTF
*/
import java.io.*;
import java.util.*;
public class ReadUTF {
private static Random generator = new Random();
private static final int TEST_ITERATIONS = 1000;
private static final int A_NUMBER_NEAR_65535 = 60000;
private static final int MAX_CORRUPTIONS_PER_CYCLE = 3;
public static final void main(String[] args) throws Exception {
for (int i=0; i<TEST_ITERATIONS; i++) {
try {
writeAndReadAString();
} catch (UTFDataFormatException utfdfe) {
if (utfdfe.getMessage() == null)
throw new RuntimeException("vague exception thrown");
} catch (EOFException eofe) {
// These are rare and beyond the scope of the test
}
}
}
private static void writeAndReadAString() throws Exception {
// Write out a string whose UTF-8 encoding is quite possibly
// longer than 65535 bytes
int length = generator.nextInt(A_NUMBER_NEAR_65535) + 1;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
StringBuffer testBuffer = new StringBuffer();
for (int i=0; i<length; i++)
testBuffer.append((char)generator.nextInt());
String testString = testBuffer.toString();
DataOutputStream dos = new DataOutputStream(baos);
dos.writeUTF(testString);
// Corrupt the data to produce malformed characters
byte[] testBytes = baos.toByteArray();
int dataLength = testBytes.length;
int corruptions = generator.nextInt(MAX_CORRUPTIONS_PER_CYCLE);
for (int i=0; i<corruptions; i++) {
int index = generator.nextInt(dataLength);
testBytes[index] = (byte)generator.nextInt();
}
// Pay special attention to mangling the end to produce
// partial characters at end
testBytes[dataLength-1] = (byte)generator.nextInt();
testBytes[dataLength-2] = (byte)generator.nextInt();
// Attempt to decode the bytes back into a String
ByteArrayInputStream bais = new ByteArrayInputStream(testBytes);
DataInputStream dis = new DataInputStream(bais);
dis.readUTF();
}
}