//
// HMACSHA1.cs: Handles HMAC with SHA-1
//
// Author:
//	Sebastien Pouliot  <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005 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.Runtime.InteropServices;

using Mono.Security.Cryptography;

namespace System.Security.Cryptography {

	// References:
	// a.	FIPS PUB 198: The Keyed-Hash Message Authentication Code (HMAC), 2002 March.
	//	http://csrc.nist.gov/publications/fips/fips198/fips-198a.pdf
	// b.	Internet RFC 2104, HMAC, Keyed-Hashing for Message Authentication
	//	(include C source for HMAC-MD5)
	//	http://www.ietf.org/rfc/rfc2104.txt
	// c.	IETF RFC2202: Test Cases for HMAC-MD5 and HMAC-SHA-1
	//	(include C source for HMAC-MD5 and HAMAC-SHA1)
	//	http://www.ietf.org/rfc/rfc2202.txt
	// d.	ANSI X9.71, Keyed Hash Message Authentication Code.
	//	not free :-(
	//	http://webstore.ansi.org/ansidocstore/product.asp?sku=ANSI+X9%2E71%2D2000

#if ! NET_2_0
	public class HMACSHA1: KeyedHashAlgorithm {
		private HMACAlgorithm hmac;
		private bool m_disposed;
	
		public HMACSHA1 () : this (KeyBuilder.Key (8))
		{
		}
	
		public HMACSHA1 (byte[] rgbKey) : base ()
		{
			hmac = new HMACAlgorithm ("SHA1");
			HashSizeValue = 160;
			Key = rgbKey;
			m_disposed = false;
		}
	
		~HMACSHA1 () 
		{
			Dispose (false);
		}
	
		public override byte[] Key {
			get { return base.Key; }
			set { 
				hmac.Key = value; 
				base.Key = value;
			}
		} 
	
		public string HashName {
			get { return hmac.HashName; }
			set { 
				// only if its not too late for a change
				if (State == 0)
					hmac.HashName = value; 
			}
		}
	
		protected override void Dispose (bool disposing) 
		{
			if (!m_disposed) {
				if (hmac != null)
					hmac.Dispose();
				base.Dispose (disposing);
				m_disposed = true;
			}
		}
	
		public override void Initialize ()
		{
			if (m_disposed)
				throw new ObjectDisposedException ("HMACSHA1");
			// let us throw an exception if hash name is invalid
			// for HMACSHA1 (obviously this can't be done by the 
			// generic HMAC class)
			if (!(hmac.Algo is SHA1)) {
				string algo = (hmac.Algo == null) ? "none" : hmac.Algo.GetType ().ToString ();
				string msg = Locale.GetText ("Invalid hash algorithm '{0}', expected '{1}'.");
				throw new InvalidCastException (String.Format (msg, algo, "SHA1"));
			}
			State = 0;
			hmac.Initialize ();
		}
	
	        protected override void HashCore (byte[] rgb, int ib, int cb)
		{
			if (m_disposed)
				throw new ObjectDisposedException ("HMACSHA1");

			if (State == 0) {
				Initialize ();
				State = 1;
			}
			hmac.Core (rgb, ib, cb);
		}
	
		protected override byte[] HashFinal ()
		{
			if (m_disposed)
				throw new ObjectDisposedException ("HMACSHA1");

			State = 0;
			return hmac.Final ();
		}
	}
#else
	[ComVisible (true)]
	public class HMACSHA1 : HMAC {

		public HMACSHA1 ()
			: this (KeyBuilder.Key (8))
		{
		}

		public HMACSHA1 (byte[] rgbKey)
		{
			HashName = "SHA1";
			HashSizeValue = 160;
			Key = rgbKey;
		}

		public HMACSHA1 (byte[] rgbKey, bool useManagedSha1)
		{
			HashName = "System.Security.Cryptography.SHA1" + (useManagedSha1 ? "Managed" : "CryptoServiceProvider");
			HashSizeValue = 160;
			Key = rgbKey;
		}
	}
#endif
}