J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* @test |
| 25 | @bug 4150737 |
| 26 | @summary Ensure that StreamTokenizer does not read any further ahead |
| 27 | than is absolutely necessary |
| 28 | */ |
| 29 | |
| 30 | import java.io.ByteArrayInputStream; |
| 31 | import java.io.InputStream; |
| 32 | import java.io.InputStreamReader; |
| 33 | import java.io.Reader; |
| 34 | import java.io.StreamTokenizer; |
| 35 | import java.io.IOException; |
| 36 | |
| 37 | |
| 38 | public class ReadAhead { |
| 39 | |
| 40 | |
| 41 | /* An InputStream subclass that cannot read past a given limit */ |
| 42 | static private class LimitedInputStream extends InputStream { |
| 43 | |
| 44 | private String input; |
| 45 | private int limit; /* Do not allow input[limit] to be read */ |
| 46 | private int next = 0; |
| 47 | |
| 48 | public LimitedInputStream(String input, int limit) { |
| 49 | this.input = input; |
| 50 | this.limit = limit; |
| 51 | } |
| 52 | |
| 53 | public int read() throws IOException { |
| 54 | if (next >= limit) |
| 55 | throw new IOException("Attempted to read too far in stream"); |
| 56 | return input.charAt(next++); |
| 57 | } |
| 58 | |
| 59 | } |
| 60 | |
| 61 | |
| 62 | /* A Reader subclass that cannot read past a given limit */ |
| 63 | static private class LimitedReader extends Reader { |
| 64 | |
| 65 | private String input; |
| 66 | private int limit; /* Do not allow input[limit] to be read */ |
| 67 | private int next = 0; |
| 68 | |
| 69 | public LimitedReader(String input, int limit) { |
| 70 | this.input = input; |
| 71 | this.limit = limit; |
| 72 | } |
| 73 | |
| 74 | public int read() throws IOException { |
| 75 | if (next >= limit) |
| 76 | throw new IOException("Attempted to read too far in stream"); |
| 77 | return input.charAt(next++); |
| 78 | } |
| 79 | |
| 80 | public int read(char[] b, int off, int len) throws IOException { |
| 81 | int top = off + len; |
| 82 | int i; |
| 83 | for (i = off; i < top; i++) { |
| 84 | int c = read(); |
| 85 | if (c < 0) break; |
| 86 | b[i] = (char)c; |
| 87 | } |
| 88 | return i - off; |
| 89 | } |
| 90 | |
| 91 | public void close() { } |
| 92 | |
| 93 | } |
| 94 | |
| 95 | |
| 96 | /* Interface for objects that can create new StreamTokenizers |
| 97 | with a given limited input */ |
| 98 | static private interface StreamTokenizerMaker { |
| 99 | public StreamTokenizer create(String input, int limit); |
| 100 | } |
| 101 | |
| 102 | static private void fail(String why) throws Exception { |
| 103 | throw new Exception(why); |
| 104 | } |
| 105 | |
| 106 | private static void test(StreamTokenizer st) throws Exception { |
| 107 | st.eolIsSignificant(true); |
| 108 | int tt = st.nextToken(); |
| 109 | if (tt != StreamTokenizer.TT_WORD) fail("expected TT_WORD"); |
| 110 | if (!st.sval.equals("foo")) fail("expected word token \"foo\""); |
| 111 | tt = st.nextToken(); |
| 112 | if (tt != StreamTokenizer.TT_EOL) fail("expected TT_EOL"); |
| 113 | } |
| 114 | |
| 115 | private static void test(StreamTokenizerMaker stm) throws Exception { |
| 116 | test(stm.create("foo\nx", 4)); |
| 117 | test(stm.create("foo\r\nx", 4)); |
| 118 | } |
| 119 | |
| 120 | |
| 121 | public static void main(String[] args) throws Exception { |
| 122 | |
| 123 | /* InputStream case */ |
| 124 | test(new StreamTokenizerMaker() { |
| 125 | public StreamTokenizer create(String input, int limit) { |
| 126 | return new StreamTokenizer(new LimitedInputStream(input, limit)); |
| 127 | }}); |
| 128 | |
| 129 | /* Reader case */ |
| 130 | test(new StreamTokenizerMaker() { |
| 131 | public StreamTokenizer create(String input, int limit) { |
| 132 | return new StreamTokenizer(new LimitedReader(input, limit)); |
| 133 | }}); |
| 134 | |
| 135 | } |
| 136 | |
| 137 | } |