public ASCII85InputStream(InputStream is) 
{
        super(is);
        index = 0;
        n = 0;
        eof = false;
        ascii = new byte[5];
        b = new byte[4];
}

Constructor.

Parameters:

is - The input stream to actually read from.

 public int available() 
{
        return 0;
}

Unsupported.

 public  void close() throws IOException 
{
        ascii = null;
        eof = true;
        b = null;
        super.close();
}

This will close the underlying stream and release any resources.

 public  void mark(int readlimit) 
{

}

Unsupported.

 public boolean markSupported() 
{
        return false;
}

non supported interface methods.

 public final int read() throws IOException 
{
        if( index  >= n )
        {
            if(eof)
            {
                return -1;
            }
            index = 0;
            int k;
            byte z;
            do
            {
                int zz=(byte)in.read();
                if(zz==-1)
                {
                    eof=true;
                    return -1;
                }
                z = (byte)zz;
            }  while( z=='\n' || z=='\r' || z==' ');
            if (z == '~' || z=='x')
            {
                eof=true;
                ascii=b=null;
                n = 0;
                return -1;
            }
            else if (z == 'z')
            {
                b[0]=b[1]=b[2]=b[3]=0;
                n = 4;
            }
            else
            {
                ascii[0]=z; // may be EOF here....
                for (k=1;k< 5;++k)
                {
                    do
                    {
                        int zz=(byte)in.read();
                        if(zz==-1)
                        {
                            eof=true;
                            return -1;
                        }
                        z=(byte)zz;
                    } while ( z=='\n' || z=='\r' || z==' ' );
                    ascii[k]=z;
                    if (z == '~' || z=='x')
                    {
                        break;
                    }
                }
                n = k - 1;
                if ( n==0 )
                {
                    eof = true;
                    ascii = null;
                    b = null;
                    return -1;
                }
                if ( k <  5 )
                {
                    for (++k; k <  5; ++k )
                    {
                        ascii[k] = 0x21;
                    }
                    eof=true;
                }
                // decode stream
                long t=0;
                for ( k=0; k< 5; ++k)
                {
                    z=(byte)(ascii[k] - 0x21);
                    if (z <  0 || z  > 93)
                    {
                        n = 0;
                        eof = true;
                        ascii = null;
                        b = null;
                        throw new IOException("Invalid data in Ascii85 stream");
                    }
                    t = (t * 85L) + z;
                }
                for ( k = 3; k >=0; --k)
                {
                    b[k] = (byte)(t & 0xFFL);
                    t > > >=8;
                }
            }
        }
        return b[index++] & 0xFF;
}

This will read the next byte from the stream.

 public final int read(byte[] data,
    int offset,
    int len) throws IOException 
{
        if(eof && index >=n)
        {
            return -1;
        }
        for(int i=0;i< len;i++)
        {
            if(index< n)
            {
                data[i+offset]=b[index++];
            }
            else
            {
                int t = read();
                if ( t == -1 )
                {
                    return i;
                }
                data[i+offset]=(byte)t;
            }
        }
        return len;
}

This will read a chunk of data.

 public  void reset() throws IOException 
{
        throw new IOException("Reset is not supported");
}

Unsupported.

 public long skip(long nValue) 
{
        return 0;
}

Unsupported.