//
// MD5Engine.h
//
// Library: Foundation
// Package: Crypt
// Module:  MD5Engine
//
// Definition of class MD5Engine.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//
//
// MD5 (RFC 1321) algorithm:
// Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
// rights reserved.
// 
// License to copy and use this software is granted provided that it
// is identified as the "RSA Data Security, Inc. MD5 Message-Digest
// Algorithm" in all material mentioning or referencing this software
// or this function.
//
// License is also granted to make and use derivative works provided
// that such works are identified as "derived from the RSA Data
// Security, Inc. MD5 Message-Digest Algorithm" in all material
// mentioning or referencing the derived work.
//
// RSA Data Security, Inc. makes no representations concerning either
// the merchantability of this software or the suitability of this
// software for any particular purpose. It is provided "as is"
// without express or implied warranty of any kind.
//
// These notices must be retained in any copies of any part of this
// documentation and/or software.
//


#ifndef Foundation_MD5Engine_INCLUDED
#define Foundation_MD5Engine_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/DigestEngine.h"


namespace Poco {


class Foundation_API MD5Engine: public DigestEngine
	/// This class implements the MD5 message digest algorithm,
	/// described in RFC 1321.
{
public:
	enum
	{
		BLOCK_SIZE  = 64,
		DIGEST_SIZE = 16
	};

	MD5Engine();
	~MD5Engine();
		
	std::size_t digestLength() const;
	void reset();
	const DigestEngine::Digest& digest();

protected:
	void updateImpl(const void* data, std::size_t length);

private:
	static void transform(UInt32 state[4], const unsigned char block[64]);
	static void encode(unsigned char* output, const UInt32* input, std::size_t len);
	static void decode(UInt32* output, const unsigned char* input, std::size_t len);

	struct Context
	{
		UInt32 state[4];          // state (ABCD)
		UInt32 count[2];          // number of bits, modulo 2^64 (lsb first)
		unsigned char buffer[64]; // input buffer
	};

	Context _context;
	DigestEngine::Digest _digest;

	MD5Engine(const MD5Engine&);
	MD5Engine& operator = (const MD5Engine&);
};


} // namespace Poco


#endif // Foundation_MD5Engine_INCLUDED