package org.jaudiotagger.audio.asf.io;

 import java.io.FilterInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 /**

  * This implementation repeatedly reads from the wrapped input stream until the

  * requested amount of bytes are read.<br>

  * 

  * @author Christian Laireiter

  */

 public class FullRequestInputStream extends FilterInputStream {

     /**

      * Creates an instance.

      * 

      * @param source

      *            stream to read from.

      */

     public FullRequestInputStream(final InputStream source) {

         super(source);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public int read(final byte[] buffer) throws IOException {

         return read(buffer, 0, buffer.length);

     }

     /**

      * {@inheritDoc}

      */

     @Override

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

             throws IOException {

         int totalRead = 0;

         int read;

         while (totalRead < len) {

             read = super.read(buffer, off + totalRead, len - totalRead);

             if (read >= 0) {

                 totalRead += read;

             }

             if (read == -1) {

                 throw new IOException((len - totalRead)

                         + " more bytes expected.");

             }

         }

         return totalRead;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public long skip(final long amount) throws IOException {

         long skipped = 0;

         int zeroSkipCnt = 0;

         long currSkipped;

         while (skipped < amount) {

             currSkipped = super.skip(amount - skipped);

             if (currSkipped == 0) {

                 zeroSkipCnt++;

                 if (zeroSkipCnt == 2) {

                     // If the skip value exceeds streams size, this and the

                     // number is extremely large, this can lead to a very long

                     // running loop.

                     break;

                 }

             }

             skipped += currSkipped;

         }

         return skipped;

     }

 }