//
// System.Web.HttpPostedFile.cs
//
// Author:
//	Dick Porter  <dick@ximian.com>
//      Ben Maurer   <benm@ximian.com>
//      Miguel de Icaza <miguel@novell.com>
//
// Copyright (C) 2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.IO;
using System.Security.Permissions;

namespace System.Web
{
	// CAS - no InheritanceDemand here as the class is sealed
	[AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
	public sealed class HttpPostedFile {
		string name;
		string content_type;
		Stream stream;
		
		class ReadSubStream : Stream {
			Stream s;
			long offset;
			long end;
			long position;
	
			public ReadSubStream (Stream s, long offset, long length)
			{
				this.s = s;
				this.offset = offset;
				this.end = offset + length;
				position = offset;
			}
	
			public override void Flush ()
			{
			}
	
			public override int Read (byte [] buffer, int dest_offset, int count)
			{
				if (buffer == null)
					throw new ArgumentNullException ("buffer");

				if (dest_offset < 0)
					throw new ArgumentOutOfRangeException ("dest_offset", "< 0");

				if (count < 0)
					throw new ArgumentOutOfRangeException ("count", "< 0");

				int len = buffer.Length;
				if (dest_offset > len)
					throw new ArgumentException ("destination offset is beyond array size");
				// reordered to avoid possible integer overflow
				if (dest_offset > len - count)
					throw new ArgumentException ("Reading would overrun buffer");

				if (count > end - position)
					count = (int) (end - position);

				if (count <= 0)
					return 0;

				s.Position = position;
				int result = s.Read (buffer, dest_offset, count);
				if (result > 0)
					position += result;
				else
					position = end;

				return result;
			}
	
			public override int ReadByte ()
			{
				if (position >= end)
					return -1;

				s.Position = position;
				int result = s.ReadByte ();
				if (result < 0)
					position = end;
				else
					position++;

				return result;
			}
	
			public override long Seek (long d, SeekOrigin origin)
			{
				long real;
				switch (origin) {
				case SeekOrigin.Begin:
					real = offset + d;
					break;
				case SeekOrigin.End:
					real = end + d;
					break;
				case SeekOrigin.Current:
					real = position + d;
					break;
				default:
					throw new ArgumentException ();
				}

				long virt = real - offset;
				if (virt < 0 || virt > Length)
					throw new ArgumentException ();

				position = s.Seek (real, SeekOrigin.Begin);
				return position;
			}
	
			public override void SetLength (long value)
			{
				throw new NotSupportedException ();
			}

			public override void Write (byte [] buffer, int offset, int count)
			{
				throw new NotSupportedException ();
			}

			public override bool CanRead {
				get { return true; }
			}
			public override bool CanSeek {
				get { return true; }
			}
			public override bool CanWrite {
				get { return false; }
			}
	
			public override long Length {
				get { return end - offset; }
			}
	
			public override long Position {
				get {
					return position - offset;
				}
				set {
					if (value > Length)
						throw new ArgumentOutOfRangeException ();

					position = Seek (value, SeekOrigin.Begin);
				}
			}
		}

		internal HttpPostedFile (string name, string content_type, Stream base_stream, long offset, long length)
		{
			this.name = name;
			this.content_type = content_type;
			this.stream = new ReadSubStream (base_stream, offset, length);
		}
		
		public string ContentType {
			get {
				return (content_type);
			}
		}

		public int ContentLength {
			get {
		  		return (int)stream.Length;
			}
		}

		public string FileName 
		{
			get {
				return (name);
			}
		}

		public Stream InputStream 
		{
			get {
				return (stream);
			}
		}

		public void SaveAs (string filename)
		{
			byte [] buffer = new byte [16*1024];
			long old_post = stream.Position;

			try {
				File.Delete (filename);
				using (FileStream fs = File.Create (filename)){
					stream.Position = 0;
					int n;
					
					while ((n = stream.Read (buffer, 0, 16*1024)) != 0){
						fs.Write (buffer, 0, n);
					}
				}
			} finally {
				stream.Position = old_post;
			}
		}
	}
}