1/* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24/* 25 * @test 26 * @bug 8010837 8011136 27 * @summary Test if available returns correct value when skipping beyond 28 * the end of a file. 29 * @author Dan Xu 30 */ 31 32import java.io.BufferedWriter; 33import java.io.File; 34import java.io.FileInputStream; 35import java.io.IOException; 36import java.nio.charset.Charset; 37import java.nio.file.Files; 38import java.nio.file.Path; 39 40public class NegativeAvailable { 41 42 public static void main(String[] args) throws IOException { 43 final int SIZE = 10; 44 final int SKIP = 5; 45 final int NEGATIVE_SKIP = -5; 46 47 // Create a temporary file with size of 10 bytes. 48 Path tmp = Files.createTempFile(null, null); 49 try (BufferedWriter writer = 50 Files.newBufferedWriter(tmp, Charset.defaultCharset())) { 51 for (int i = 0; i < SIZE; i++) { 52 writer.write('1'); 53 } 54 } 55 56 File tempFile = tmp.toFile(); 57 try (FileInputStream fis = new FileInputStream(tempFile)) { 58 if (tempFile.length() != SIZE) { 59 throw new RuntimeException("unexpected file size = " 60 + tempFile.length()); 61 } 62 long space = skipBytes(fis, SKIP, SIZE); 63 space = skipBytes(fis, NEGATIVE_SKIP, space); 64 space = skipBytes(fis, SKIP, space); 65 space = skipBytes(fis, SKIP, space); 66 space = skipBytes(fis, SKIP, space); 67 space = skipBytes(fis, NEGATIVE_SKIP, space); 68 space = skipBytes(fis, NEGATIVE_SKIP, space); 69 } 70 Files.deleteIfExists(tmp); 71 } 72 73 /** 74 * Skip toSkip number of bytes and return the remaining bytes of the file. 75 */ 76 private static long skipBytes(FileInputStream fis, int toSkip, long space) 77 throws IOException { 78 long skip = fis.skip(toSkip); 79 if (skip != toSkip) { 80 throw new RuntimeException("skip() returns " + skip 81 + " but expected " + toSkip); 82 } 83 long newSpace = space - toSkip; 84 long remaining = newSpace > 0 ? newSpace : 0; 85 int avail = fis.available(); 86 if (avail != remaining) { 87 throw new RuntimeException("available() returns " + avail 88 + " but expected " + remaining); 89 } 90 91 System.out.println("Skipped " + skip + " bytes " 92 + " available() returns " + avail); 93 return newSpace; 94 } 95} 96