libjava/java/io/FileInputStream.java

   1 /* Copyright (C) 1998, 1999, 2001, 2002, 2003  Free Software Foundation
   2
   3    This file is part of libgcj.
   4
   5 This software is copyrighted work licensed under the terms of the
   6 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   7 details.  */
   8
   9 package java.io;
  10
  11 import java.nio.channels.FileChannel;
  12
  13 /**
  14  * @author Warren Levy <warrenl@cygnus.com>
  15  * @date October 28, 1998.
  16  */
  17 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
  18  * "The Java Language Specification", ISBN 0-201-63451-1
  19  * plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
  20  * Status:  Believed complete and correct.
  21  */
  22
  23 public class FileInputStream extends InputStream
  24 {
  25   /* Contains the file descriptor for referencing the actual file. */
  26   private FileDescriptor fd;
  27
  28   private FileChannel ch;
  29
  30   public FileInputStream(String name) throws FileNotFoundException
  31   {
  32     SecurityManager s = System.getSecurityManager();
  33     if (s != null)
  34       s.checkRead(name);
  35     fd = new FileDescriptor(name, FileDescriptor.READ);
  36   }
  37
  38   public FileInputStream(File file) throws FileNotFoundException
  39   {
  40     this(file.getPath());
  41   }
  42
  43   public FileInputStream(FileDescriptor fdObj)
  44   {
  45     SecurityManager s = System.getSecurityManager();
  46     if (s != null)
  47       s.checkRead(fdObj);
  48     fd = fdObj;
  49   }
  50
  51   public int available() throws IOException
  52   {
  53     return fd.available();
  54   }
  55
  56   public void close() throws IOException
  57   {
  58     if (fd.valid())
  59       fd.close();
  60   }
  61
  62   protected void finalize() throws IOException
  63   {
  64     // We don't actually need this, but we include it because it is
  65     // mentioned in the JCL.
  66   }
  67
  68   public final FileDescriptor getFD() throws IOException
  69   {
  70     if (!fd.valid())
  71       throw new IOException();
  72     return fd;
  73   }
  74
  75   public int read() throws IOException
  76   {
  77     return fd.read();
  78   }
  79
  80   public int read(byte[] b) throws IOException
  81   {
  82     return fd.read(b, 0, b.length);
  83   }
  84
  85   public int read(byte[] b, int off, int len) throws IOException
  86   {
  87     if (off < 0 || len < 0 || off + len > b.length)
  88       throw new ArrayIndexOutOfBoundsException();
  89
  90     return fd.read(b, off, len);
  91   }
  92
  93   public long skip(long n) throws IOException
  94   {
  95     long startPos = fd.getFilePointer();
  96     long endPos = fd.seek(n, FileDescriptor.CUR, true);
  97     return endPos - startPos;
  98   }
  99
 100   public FileChannel getChannel ()
 101   {
 102     return ch;
 103   }
 104 }