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      1 /*
      2  * SeekableFileInputStream
      3  *
      4  * Author: Lasse Collin <lasse.collin (at) tukaani.org>
      5  *
      6  * This file has been put into the public domain.
      7  * You can do whatever you want with this file.
      8  */
      9 
     10 package org.tukaani.xz;
     11 
     12 import java.io.File;
     13 import java.io.RandomAccessFile;
     14 import java.io.IOException;
     15 import java.io.FileNotFoundException;
     16 
     17 /**
     18  * Wraps a {@link java.io.RandomAccessFile RandomAccessFile}
     19  * in a SeekableInputStream.
     20  */
     21 public class SeekableFileInputStream extends SeekableInputStream {
     22     /**
     23      * The RandomAccessFile that has been wrapped
     24      * into a SeekableFileInputStream.
     25      */
     26     protected RandomAccessFile randomAccessFile;
     27 
     28     /**
     29      * Creates a new seekable input stream that reads from the specified file.
     30      */
     31     public SeekableFileInputStream(File file) throws FileNotFoundException {
     32         randomAccessFile = new RandomAccessFile(file, "r");
     33     }
     34 
     35     /**
     36      * Creates a new seekable input stream that reads from a file with
     37      * the specified name.
     38      */
     39     public SeekableFileInputStream(String name) throws FileNotFoundException {
     40         randomAccessFile = new RandomAccessFile(name, "r");
     41     }
     42 
     43     /**
     44      * Creates a new seekable input stream from an existing
     45      * <code>RandomAccessFile</code> object.
     46      */
     47     public SeekableFileInputStream(RandomAccessFile randomAccessFile) {
     48         this.randomAccessFile = randomAccessFile;
     49     }
     50 
     51     /**
     52      * Calls {@link RandomAccessFile#read() randomAccessFile.read()}.
     53      */
     54     public int read() throws IOException {
     55         return randomAccessFile.read();
     56     }
     57 
     58     /**
     59      * Calls {@link RandomAccessFile#read(byte[]) randomAccessFile.read(buf)}.
     60      */
     61     public int read(byte[] buf) throws IOException {
     62         return randomAccessFile.read(buf);
     63     }
     64 
     65     /**
     66      * Calls
     67      * {@link RandomAccessFile#read(byte[],int,int)
     68      *        randomAccessFile.read(buf, off, len)}.
     69      */
     70     public int read(byte[] buf, int off, int len) throws IOException {
     71         return randomAccessFile.read(buf, off, len);
     72     }
     73 
     74     /**
     75      * Calls {@link RandomAccessFile#close() randomAccessFile.close()}.
     76      */
     77     public void close() throws IOException {
     78         randomAccessFile.close();
     79     }
     80 
     81     /**
     82      * Calls {@link RandomAccessFile#length() randomAccessFile.length()}.
     83      */
     84     public long length() throws IOException {
     85         return randomAccessFile.length();
     86     }
     87 
     88     /**
     89      * Calls {@link RandomAccessFile#getFilePointer()
     90                     randomAccessFile.getFilePointer()}.
     91      */
     92     public long position() throws IOException {
     93         return randomAccessFile.getFilePointer();
     94     }
     95 
     96     /**
     97      * Calls {@link RandomAccessFile#seek(long) randomAccessFile.seek(long)}.
     98      */
     99     public void seek(long pos) throws IOException {
    100         randomAccessFile.seek(pos);
    101     }
    102 }
    103