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(InputStream source) {

                 super(source);

         }

         /**

      * {@inheritDoc}

      */

         @Override

         public int read(byte[] b) throws IOException {

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

         }

         /**

      * {@inheritDoc}

      */

         @Override

         public int read(byte[] b, int off, int len) throws IOException {

                 int totalRead = 0;

                 int read = -1;

                 while (totalRead < len) {

                         read = super.read(b, 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(long n) throws IOException {

                 long skipped = 0;

                 int zeroSkipCnt = 0;

                 long currSkipped;

                 while (skipped < n) {

                         currSkipped = super.skip(n - 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.

                                         return skipped;

                                 }

                         }

                         skipped += currSkipped;

                 }

                 return skipped;

         }

 }