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test/jdk/java/io/InputStream/Skip.java
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 1997, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2018 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.
@@ -19,28 +19,26 @@
* 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 4016710
- @summary check for correct implementation of InputStream.skip
+/**
+ * @test
+ * @bug 4016710 6516099
+ * @summary check for correct implementation of InputStream.skip{NBytes}
*/
-import java.io.*;
-
-
-public class Skip{
+import java.io.EOFException;
+import java.io.InputStream;
+import java.io.IOException;
- private static void dotest(InputStream in , int curpos ,
- long total , long toskip , long expected)
- throws Exception
- {
+public class Skip {
+ private static final int EOF = -1;
+ private static void dotest(InputStream in, int curpos, long total,
+ long toskip, long expected) throws Exception {
try {
-
System.err.println("\n\nCurrently at pos = " + curpos +
"\nTotal bytes in the Stream = " + total +
"\nNumber of bytes to skip = " + toskip +
"\nNumber of bytes that should be skipped = " +
expected);
@@ -48,47 +46,73 @@
long skipped = in.skip(toskip);
System.err.println("actual number skipped: "+ skipped);
if ((skipped < 0) || (skipped > expected)) {
- throw new RuntimeException("Unexpected number of bytes skipped");
+ throw new RuntimeException("Unexpected byte count skipped");
}
-
} catch (IOException e) {
- System.err.println("IOException is thrown - possible result");
+ System.err.println("IOException is thrown: " + e);
} catch (Throwable e) {
- throw new RuntimeException("Unexpected "+e+" is thrown!");
+ throw new RuntimeException("Unexpected " + e + " is thrown!");
}
+ }
+
+ private static void dotestExact(MyInputStream in, long curpos, long total,
+ long toskip, boolean expectIOE, boolean expectEOFE) {
+ System.err.println("\n\nCurrently at pos = " + curpos +
+ "\nTotal bytes in the Stream = " + total +
+ "\nNumber of bytes to skip = " + toskip);
+
+ try {
+ long pos = in.position();
+ assert pos == curpos : pos + " != " + curpos;
+ in.skipNBytes(toskip);
+ if (in.position() != pos + (toskip < 0 ? 0 : toskip)) {
+ throw new RuntimeException((in.position() - pos) +
+ " bytes skipped; expected " + toskip);
+ }
+ } catch (EOFException eofe) {
+ if (!expectEOFE) {
+ throw new RuntimeException("Unexpected EOFException", eofe);
+ }
+ System.err.println("Caught expected EOFException");
+ } catch (IOException ioe) {
+ if (!expectIOE) {
+ throw new RuntimeException("Unexpected IOException", ioe);
+ }
+ System.err.println("Caught expected IOException");
+ }
}
public static void main( String argv[] ) throws Exception {
-
MyInputStream in = new MyInputStream(11);
- /* test for negative skip */
+ // test for negative skip
dotest(in, 0, 11, -23, 0);
- /* check for skip beyond EOF starting from before EOF */
+ // check for skip beyond EOF starting from before EOF
dotest(in, 0, 11, 20, 11);
- /* check for skip after EOF */
- dotest(in, -1, 11, 20, 0);
+ // check for skip after EOF
+ dotest(in, EOF, 11, 20, 0);
in = new MyInputStream(9000);
- /* check for skip equal to the read chunk size in InputStream.java */
+
+ // check for skip equal to the read chunk size in InputStream.java
dotest(in, 0, 9000, 2048, 2048);
- /* check for skip greater than the read chunk size in InputStream.java */
+ // check for skip larger than the read chunk size in InputStream.java
dotest(in, 2048, 9000, 5000, 5000);
- /* check for skip beyond EOF starting from before EOF */
+ // check for skip beyond EOF starting from before EOF
dotest(in, 7048, 9000, 5000, 1952);
in = new MyInputStream(5000);
- /* check for multiple chunk reads */
+ // check for multiple chunk reads
dotest(in, 0, 5000, 6000, 5000);
/*
* check for skip larger than Integer.MAX_VALUE
* (Takes about 2 hrs on a sparc ultra-1)
@@ -96,31 +120,109 @@
* long toskip = total - (long)6;
* in = new MyInputStream(total);
* dotest(in, 0, total, toskip, toskip);
*/
- }
+ // tests for skipping an exact number of bytes
+
+ final long streamLength = Long.MAX_VALUE;
+ in = new MyInputStream(streamLength);
+ // negative skip: OK
+ dotestExact(in, 0, streamLength, -1, false, false);
+
+ // negative skip at EOF: OK
+ in.position(streamLength);
+ dotestExact(in, streamLength, streamLength, -1, false, false);
+ in.position(0);
+
+ // zero skip: OK
+ dotestExact(in, 0, streamLength, 0, false, false);
+
+ // zero skip at EOF: OK
+ in.position(streamLength);
+ dotestExact(in, streamLength, streamLength, 0, false, false);
+
+ // skip(1) at EOF: EOFE
+ dotestExact(in, streamLength, streamLength, 1, false, true);
+ in.position(0);
+
+ final long n = 31; // skip count
+ long pos = 0;
+
+ // skip(n) returns negative value: IOE
+ in.setState(-1, 100);
+ dotestExact(in, pos, streamLength, n, true, false);
+
+ // skip(n) returns n + 1: IOE
+ in.setState(n + 1, 100);
+ dotestExact(in, pos, streamLength, n, true, false);
+ pos += n + 1;
+
+ // skip(n) returns n/2 but only n/4 subsequent reads succeed: EOFE
+ in.setState(n/2, n/2 + n/4);
+ dotestExact(in, pos, streamLength, n, false, true);
+ pos += n/2 + n/4;
+
+ // skip(n) returns n/2 but n - n/2 subsequent reads succeed: OK
+ in.setState(n/2, n);
+ dotestExact(in, pos, streamLength, n, false, false);
+ pos += n;
+ }
}
class MyInputStream extends InputStream {
+ private static final int EOF = -1;
+
+ private final long endoffile;
+
+ private long readctr = 0;
- private int readctr = 0;
- private long endoffile;
+ private boolean isStateSet = false;
+ private long skipReturn;
+ private long readLimit;
public MyInputStream(long endoffile) {
this.endoffile = endoffile;
}
- public int read() {
+ /**
+ * Limits the behavior of skip() and read().
+ *
+ * @param skipReturn the value to be returned by skip()
+ * @param maxReads the maximum number of reads past the current position
+ * before EOF is reached
+ */
+ public void setState(long skipReturn, long maxReads) {
+ this.skipReturn = skipReturn;
+ this.readLimit = readctr + maxReads;
+ isStateSet = true;
+ }
- if (readctr == endoffile) {
- return -1;
+ public int read() {
+ if (readctr == endoffile ||
+ (isStateSet && readctr >= readLimit)) {
+ return EOF;
}
else {
readctr++;
return 0;
}
}
public int available() { return 0; }
+
+ public long position() { return readctr; }
+
+ public void position(long pos) {
+ readctr = pos < 0 ? 0 : Math.min(pos, endoffile);
+ }
+
+ public long skip(long n) throws IOException {
+ if (isStateSet) {
+ return skipReturn < 0 ? skipReturn : super.skip(skipReturn);
+ }
+
+ // InputStream skip implementation.
+ return super.skip(n); // readctr is implicitly incremented
+ }
}
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