libjava/java/io/FileInputStream.java

   1 /* Copyright (C) 1998, 1999  Red Hat, Inc.
   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 /**
  12  * @author Warren Levy <warrenl@cygnus.com>
  13  * @date October 28, 1998.
  14  */
  15 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
  16  * "The Java Language Specification", ISBN 0-201-63451-1
  17  * plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
  18  * Status:  Believed complete and correct.
  19  */
  20
  21 public class FileInputStream extends InputStream
  22 {
  23   /* Contains the file descriptor for referencing the actual file. */
  24   private FileDescriptor fd;
  25
  26   public FileInputStream(String name) throws FileNotFoundException
  27   {
  28     SecurityManager s = System.getSecurityManager();
  29     if (s != null)
  30       s.checkRead(name);
  31     fd = new FileDescriptor(name, FileDescriptor.READ);
  32   }
  33
  34   public FileInputStream(File file) throws FileNotFoundException
  35   {
  36     this(file.getPath());
  37   }
  38
  39   public FileInputStream(FileDescriptor fdObj)
  40   {
  41     SecurityManager s = System.getSecurityManager();
  42     if (s != null)
  43       s.checkRead(fdObj);
  44     fd = fdObj;
  45   }
  46
  47   public int available() throws IOException
  48   {
  49     return fd.available();
  50   }
  51
  52   public void close() throws IOException
  53   {
  54     if (fd == null)
  55       return;
  56
  57     fd.close();
  58     fd = null;
  59   }
  60
  61   protected void finalize() throws IOException
  62   {
  63     if (fd != null)
  64       fd.finalize();
  65   }
  66
  67   public final FileDescriptor getFD() throws IOException
  68   {
  69     if (!fd.valid())
  70       throw new IOException();
  71     return fd;
  72   }
  73
  74   public int read() throws IOException
  75   {
  76     return fd.read();
  77   }
  78
  79   public int read(byte[] b) throws IOException
  80   {
  81     return fd.read(b, 0, b.length);
  82   }
  83
  84   public int read(byte[] b, int off, int len) throws IOException
  85   {
  86     if (off < 0 || len < 0 || off + len > b.length)
  87       throw new ArrayIndexOutOfBoundsException();
  88
  89     return fd.read(b, off, len);
  90   }
  91
  92   public long skip(long n) throws IOException
  93   {
  94     return fd.seek(n, FileDescriptor.CUR);
  95   }
  96 }