/* Copyright (c) Citrix Systems, Inc. 
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met: 
 * 
 * *   Redistributions of source code must retain the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer. 
 * *   Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE.
 */

using System;
using System.IO;

namespace CommandLib
{
    public class IO
    {
        private static void unmarshal_n_into(Stream stream, uint n, byte[] buffer)
        {
            int toread = (int)n;
            int offset = 0;
            while (toread > 0)
            {
                int nread = stream.Read(buffer, offset, toread);
                if (nread <= 0)
                    throw new EndOfStreamException
                        (String.Format("End of stream reached with {0} bytes left to read", toread));

                offset += nread;
                toread -= nread;
            }
        }

        public static byte[] unmarshal_n(Stream stream, uint n)
        {
            byte[] buffer = new byte[n];
            unmarshal_n_into(stream, n, buffer);
            return buffer;
        }

        public static void skip(Stream stream, uint n)
        {
            byte[] buffer = new byte[63356];
            while (n > 0)
            {
                uint toread = (uint)buffer.Length;
                if (n < toread) toread = n;
                unmarshal_n_into(stream, toread, buffer);
                n -= toread;
            }
        }
    }
}