6720170: ByteArrayInputStream.skip(long) can overflow internally
Reviewed-by: dholmes, alanb
--- a/jdk/src/share/classes/java/io/ByteArrayInputStream.java Tue Nov 02 15:04:13 2010 +0000
+++ b/jdk/src/share/classes/java/io/ByteArrayInputStream.java Thu Nov 04 14:19:31 2010 -0700
@@ -179,11 +179,14 @@
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
}
+
if (pos >= count) {
return -1;
}
- if (pos + len > count) {
- len = count - pos;
+
+ int avail = count - pos;
+ if (len > avail) {
+ len = avail;
}
if (len <= 0) {
return 0;
@@ -206,14 +209,13 @@
* @return the actual number of bytes skipped.
*/
public synchronized long skip(long n) {
- if (pos + n > count) {
- n = count - pos;
+ long k = count - pos;
+ if (n < k) {
+ k = n < 0 ? 0 : n;
}
- if (n < 0) {
- return 0;
- }
- pos += n;
- return n;
+
+ pos += k;
+ return k;
}
/**
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/io/ByteArrayInputStream/Skip.java Thu Nov 04 14:19:31 2010 -0700
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2010, 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 6720170
+ * @summary check for ByteArrayInputStream.skip
+ */
+
+import java.io.*;
+
+public class Skip {
+ private static void dotest(InputStream in, int curpos, long total,
+ long toskip, long expected)
+ throws Exception
+ {
+ System.err.println("\nCurrently at pos = " + curpos +
+ "\nTotal bytes in the stream = " + total +
+ "\nNumber of bytes to skip = " + toskip +
+ "\nNumber of bytes that should be skipped = " +
+ expected);
+
+ // position to curpos; EOF if negative
+ in.reset();
+ int avail = curpos >= 0 ? curpos : in.available();
+ long n = in.skip(avail);
+ if (n != avail) {
+ throw new RuntimeException("Unexpected number of bytes skipped = " + n);
+ }
+
+ long skipped = in.skip(toskip);
+ System.err.println("actual number skipped: "+ skipped);
+
+ if (skipped != expected) {
+ throw new RuntimeException("Unexpected number of bytes skipped = " + skipped);
+ }
+ }
+
+ public static void main(String argv[]) throws Exception {
+ int total = 1024;
+ ByteArrayInputStream in = new ByteArrayInputStream(new byte[total]);
+
+ /* test for skip */
+ dotest(in, 0, total, 23, 23);
+ dotest(in, 10, total, 23, 23);
+
+ /* test for negative skip */
+ dotest(in, 0, total, -23, 0);
+
+ /* check for skip after EOF */
+ dotest(in, -1, total, 20, 0);
+
+ /* check for skip beyond EOF starting from before EOF */
+ dotest(in, 0, total, total+20, total);
+
+ /* check for skip if the pos + toskip causes integer overflow */
+ dotest(in, 10, total, Long.MAX_VALUE, total-10);
+ }
+}