1 /*
   2  * Copyright (c) 1997, 2017, 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 
  33 package jdk.test.lib.hprof.parser;
  34 
  35 import java.io.IOException;
  36 import java.io.RandomAccessFile;
  37 
  38 /**
  39  * Implementation of ReadBuffer using a RandomAccessFile
  40  *
  41  * @author A. Sundararajan
  42  */
  43 class 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     @Override
  61     public synchronized char getChar(long pos) throws IOException {
  62         seek(pos);
  63         return file.readChar();
  64     }
  65 
  66     @Override
  67     public synchronized byte getByte(long pos) throws IOException {
  68         seek(pos);
  69         return (byte) file.read();
  70     }
  71 
  72     @Override
  73     public synchronized short getShort(long pos) throws IOException {
  74         seek(pos);
  75         return file.readShort();
  76     }
  77 
  78     @Override
  79     public synchronized int getInt(long pos) throws IOException {
  80         seek(pos);
  81         return file.readInt();
  82     }
  83 
  84     @Override
  85     public synchronized long getLong(long pos) throws IOException {
  86         seek(pos);
  87         return file.readLong();
  88     }
  89 
  90     @Override
  91     public void close() throws Exception {
  92         file.close();
  93     }
  94 }