//
// This file is part of the aMule Project.
//
// Copyright (c) 2003-2009 aMule Team ( admin@amule.org / http://www.amule.org )
// Copyright (c) 2002 Merkur ( devs@emule-project.net / http://www.emule-project.net )
//
// Any parts of this program derived from the xMule, lMule or eMule project,
// or contributed by third-party developers are copyrighted by their
// respective authors.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA
//

#ifndef __RC4ENCRYPT_H__
#define __RC4ENCRYPT_H__


#include <vector>


#include "Types.h"
#include <common/StringFunctions.h>
#include "MemFile.h"

// Helper class

class MD5Sum;

class RC4_Key_Struct
{
public:
	uint8 abyState[256];
	uint8 byX;
	uint8 byY;
	
public:
	RC4_Key_Struct() {}
	~RC4_Key_Struct() {}
};


class CRC4EncryptableBuffer : public CMemFile
{
public:
	// Create, empty
	CRC4EncryptableBuffer();

	// Clear memory
	~CRC4EncryptableBuffer();

	// Appends to the end, checking encrypted state.
	void Append(const uint8* buffer, int n);

	// Sets the encryption key
	void SetKey(const MD5Sum& keyhash, bool bSkipDiscard = false);

	// RC4 encrypts the internal buffer. Marks it as encrypted, any other further call 
	// to add data, as Append(), must assert if the inner data is encrypted.
	// Make sure to check SetKey has been called!
	void Encrypt();

	// RC4 encrypts an external buffer with the current key.
	void RC4Crypt(const uint8 *pachIn, uint8 *pachOut, uint32 nLen);
	
	// Returns a uint8* buffer with a copy of the internal data, and clears the internal one.
	uint8* Detach();

	// Also clears the encryption flag	
	void ResetData();

	// Resets everything, as if the object has just been created.
	void FullReset();

private:
	bool m_encrypted;
	bool m_hasKey;
	RC4_Key_Struct m_key;
	
	void RC4CreateKey(const uint8* pachKeyData, uint32 nLen, bool bSkipDiscard);
};

#endif // __RC4ENCRYPT_H__
