229 lines
7.4 KiB
Java
229 lines
7.4 KiB
Java
/*
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* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 4016710 6516099
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* @summary check for correct implementation of InputStream.skip{NBytes}
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*/
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import java.io.EOFException;
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import java.io.InputStream;
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import java.io.IOException;
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public class Skip {
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private static final int EOF = -1;
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private static void dotest(InputStream in, int curpos, long total,
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long toskip, long expected) throws Exception {
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try {
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System.err.println("\n\nCurrently at pos = " + curpos +
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"\nTotal bytes in the Stream = " + total +
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"\nNumber of bytes to skip = " + toskip +
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"\nNumber of bytes that should be skipped = " +
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expected);
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long skipped = in.skip(toskip);
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System.err.println("actual number skipped: "+ skipped);
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if ((skipped < 0) || (skipped > expected)) {
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throw new RuntimeException("Unexpected byte count skipped");
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}
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} catch (IOException e) {
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System.err.println("IOException is thrown: " + e);
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} catch (Throwable e) {
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throw new RuntimeException("Unexpected " + e + " is thrown!");
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}
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}
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private static void dotestExact(MyInputStream in, long curpos, long total,
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long toskip, boolean expectIOE, boolean expectEOFE) {
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System.err.println("\n\nCurrently at pos = " + curpos +
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"\nTotal bytes in the Stream = " + total +
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"\nNumber of bytes to skip = " + toskip);
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try {
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long pos = in.position();
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assert pos == curpos : pos + " != " + curpos;
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in.skipNBytes(toskip);
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if (in.position() != pos + (toskip < 0 ? 0 : toskip)) {
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throw new RuntimeException((in.position() - pos) +
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" bytes skipped; expected " + toskip);
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}
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} catch (EOFException eofe) {
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if (!expectEOFE) {
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throw new RuntimeException("Unexpected EOFException", eofe);
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}
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System.err.println("Caught expected EOFException");
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} catch (IOException ioe) {
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if (!expectIOE) {
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throw new RuntimeException("Unexpected IOException", ioe);
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}
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System.err.println("Caught expected IOException");
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}
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}
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public static void main( String argv[] ) throws Exception {
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MyInputStream in = new MyInputStream(11);
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// test for negative skip
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dotest(in, 0, 11, -23, 0);
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// check for skip beyond EOF starting from before EOF
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dotest(in, 0, 11, 20, 11);
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// check for skip after EOF
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dotest(in, EOF, 11, 20, 0);
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in = new MyInputStream(9000);
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// check for skip equal to the read chunk size in InputStream.java
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dotest(in, 0, 9000, 2048, 2048);
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// check for skip larger than the read chunk size in InputStream.java
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dotest(in, 2048, 9000, 5000, 5000);
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// check for skip beyond EOF starting from before EOF
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dotest(in, 7048, 9000, 5000, 1952);
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in = new MyInputStream(5000);
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// check for multiple chunk reads
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dotest(in, 0, 5000, 6000, 5000);
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/*
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* check for skip larger than Integer.MAX_VALUE
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* (Takes about 2 hrs on a sparc ultra-1)
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* long total = (long)Integer.MAX_VALUE + (long)10;
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* long toskip = total - (long)6;
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* in = new MyInputStream(total);
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* dotest(in, 0, total, toskip, toskip);
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*/
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// tests for skipping an exact number of bytes
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final long streamLength = Long.MAX_VALUE;
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in = new MyInputStream(streamLength);
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// negative skip: OK
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dotestExact(in, 0, streamLength, -1, false, false);
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// negative skip at EOF: OK
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in.position(streamLength);
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dotestExact(in, streamLength, streamLength, -1, false, false);
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in.position(0);
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// zero skip: OK
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dotestExact(in, 0, streamLength, 0, false, false);
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// zero skip at EOF: OK
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in.position(streamLength);
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dotestExact(in, streamLength, streamLength, 0, false, false);
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// skip(1) at EOF: EOFE
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dotestExact(in, streamLength, streamLength, 1, false, true);
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in.position(0);
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final long n = 31; // skip count
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long pos = 0;
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// skip(n) returns negative value: IOE
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in.setState(-1, 100);
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dotestExact(in, pos, streamLength, n, true, false);
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// skip(n) returns n + 1: IOE
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in.setState(n + 1, 100);
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dotestExact(in, pos, streamLength, n, true, false);
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pos += n + 1;
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// skip(n) returns n/2 but only n/4 subsequent reads succeed: EOFE
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in.setState(n/2, n/2 + n/4);
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dotestExact(in, pos, streamLength, n, false, true);
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pos += n/2 + n/4;
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// skip(n) returns n/2 but n - n/2 subsequent reads succeed: OK
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in.setState(n/2, n);
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dotestExact(in, pos, streamLength, n, false, false);
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pos += n;
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}
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}
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class MyInputStream extends InputStream {
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private static final int EOF = -1;
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private final long endoffile;
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private long readctr = 0;
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private boolean isStateSet = false;
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private long skipReturn;
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private long readLimit;
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public MyInputStream(long endoffile) {
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this.endoffile = endoffile;
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}
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/**
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* Limits the behavior of skip() and read().
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*
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* @param skipReturn the value to be returned by skip()
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* @param maxReads the maximum number of reads past the current position
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* before EOF is reached
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*/
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public void setState(long skipReturn, long maxReads) {
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this.skipReturn = skipReturn;
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this.readLimit = readctr + maxReads;
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isStateSet = true;
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}
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public int read() {
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if (readctr == endoffile ||
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(isStateSet && readctr >= readLimit)) {
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return EOF;
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}
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else {
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readctr++;
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return 0;
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}
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}
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public int available() { return 0; }
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public long position() { return readctr; }
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public void position(long pos) {
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readctr = pos < 0 ? 0 : Math.min(pos, endoffile);
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}
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public long skip(long n) throws IOException {
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if (isStateSet) {
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return skipReturn < 0 ? skipReturn : super.skip(skipReturn);
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}
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// InputStream skip implementation.
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return super.skip(n); // readctr is implicitly incremented
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}
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}
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