package org.jaudiotagger.audio.asf.io;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.RandomAccessFile;

 /**

  * Wraps a {@link RandomAccessFile} into an {@link InputStream}.<br>

  * 

  * @author Christian Laireiter

  */

 public final class RandomAccessFileInputstream extends InputStream {

     /**

      * The file access to read from.<br>

      */

     private final RandomAccessFile source;

     /**

      * Creates an instance that will provide {@link InputStream} functionality

      * on the given {@link RandomAccessFile} by delegating calls.<br>

      * 

      * @param file

      *            The file to read.

      */

     public RandomAccessFileInputstream(final RandomAccessFile file) {

         super();

         if (file == null) {

             throw new IllegalArgumentException("null");

         }

         this.source = file;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public int read() throws IOException {

         return this.source.read();

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public int read(final byte[] buffer, final int off, final int len)

             throws IOException {

         return this.source.read(buffer, off, len);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public long skip(final long amount) throws IOException {

         if (amount < 0) {

             throw new IllegalArgumentException("invalid negative value");

         }

         long left = amount;

         while (left > Integer.MAX_VALUE) {

             this.source.skipBytes(Integer.MAX_VALUE);

             left -= Integer.MAX_VALUE;

         }

         return this.source.skipBytes((int) left);

     }

 }