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/*
* Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* 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.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* @test
@bug 4150737
@summary Ensure that StreamTokenizer does not read any further ahead
than is absolutely necessary
*/
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StreamTokenizer;
import java.io.IOException;
public class ReadAhead {
/* An InputStream subclass that cannot read past a given limit */
private static class LimitedInputStream extends InputStream {
private String input;
private int limit; /* Do not allow input[limit] to be read */
private int next = 0;
public LimitedInputStream(String input, int limit) {
this.input = input;
this.limit = limit;
}
public int read() throws IOException {
if (next >= limit)
throw new IOException("Attempted to read too far in stream");
return input.charAt(next++);
}
}
/* A Reader subclass that cannot read past a given limit */
private static class LimitedReader extends Reader {
private String input;
private int limit; /* Do not allow input[limit] to be read */
private int next = 0;
public LimitedReader(String input, int limit) {
this.input = input;
this.limit = limit;
}
public int read() throws IOException {
if (next >= limit)
throw new IOException("Attempted to read too far in stream");
return input.charAt(next++);
}
public int read(char[] b, int off, int len) throws IOException {
int top = off + len;
int i;
for (i = off; i < top; i++) {
int c = read();
if (c < 0) break;
b[i] = (char)c;
}
return i - off;
}
public void close() { }
}
/* Interface for objects that can create new StreamTokenizers
with a given limited input */
private static interface StreamTokenizerMaker {
public StreamTokenizer create(String input, int limit);
}
private static void fail(String why) throws Exception {
throw new Exception(why);
}
private static void test(StreamTokenizer st) throws Exception {
st.eolIsSignificant(true);
int tt = st.nextToken();
if (tt != StreamTokenizer.TT_WORD) fail("expected TT_WORD");
if (!st.sval.equals("foo")) fail("expected word token \"foo\"");
tt = st.nextToken();
if (tt != StreamTokenizer.TT_EOL) fail("expected TT_EOL");
}
private static void test(StreamTokenizerMaker stm) throws Exception {
test(stm.create("foo\nx", 4));
test(stm.create("foo\r\nx", 4));
}
public static void main(String[] args) throws Exception {
/* InputStream case */
test(new StreamTokenizerMaker() {
public StreamTokenizer create(String input, int limit) {
return new StreamTokenizer(new LimitedInputStream(input, limit));
}});
/* Reader case */
test(new StreamTokenizerMaker() {
public StreamTokenizer create(String input, int limit) {
return new StreamTokenizer(new LimitedReader(input, limit));
}});
}
}
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