FileReadBuffer.java revision 2224:2a8815d86b93 
1/*
2 * Copyright (c) 1997, 2016, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26
27/*
28 * The Original Code is HAT. The Initial Developer of the
29 * Original Code is Bill Foote, with contributions from others
30 * at JavaSoft/Sun.
31 */
32
33package jdk.test.lib.hprof.parser;
34
35import java.io.IOException;
36import java.io.RandomAccessFile;
37
38/**
39 * Implementation of ReadBuffer using a RandomAccessFile
40 *
41 * @author A. Sundararajan
42 */
43class FileReadBuffer implements ReadBuffer {
44    // underlying file to read
45    private RandomAccessFile file;
46
47    FileReadBuffer(RandomAccessFile file) {
48        this.file = file;
49    }
50
51    private void seek(long pos) throws IOException {
52        file.getChannel().position(pos);
53    }
54
55    public synchronized void get(long pos, byte[] buf) throws IOException {
56        seek(pos);
57        file.read(buf);
58    }
59
60    public synchronized char getChar(long pos) throws IOException {
61        seek(pos);
62        return file.readChar();
63    }
64
65    public synchronized byte getByte(long pos) throws IOException {
66        seek(pos);
67        return (byte) file.read();
68    }
69
70    public synchronized short getShort(long pos) throws IOException {
71        seek(pos);
72        return file.readShort();
73    }
74
75    public synchronized int getInt(long pos) throws IOException {
76        seek(pos);
77        return file.readInt();
78    }
79
80    public synchronized long getLong(long pos) throws IOException {
81        seek(pos);
82        return file.readLong();
83    }
84
85    @Override
86    public void close() throws Exception {
87        file.close();
88    }
89}
90