/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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 Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#ifndef _D_LIBSSL_ARC4_CONTEXT_H_
#define _D_LIBSSL_ARC4_CONTEXT_H_

#include "common.h"
#include "DlAbortEx.h"
#include "StringFormat.h"
#include <openssl/evp.h>
#include <openssl/err.h>

namespace aria2 {

class LibsslARC4Context {
private:
  EVP_CIPHER_CTX* _cipherCtx;

  void handleError() const
  {
    throw DlAbortEx
      (StringFormat("Exception in libssl routine(ARC4Context class): %s",
		    ERR_error_string(ERR_get_error(), 0)).str());
  }
public:
  LibsslARC4Context():_cipherCtx(0) {}

  ~LibsslARC4Context()
  {
    if(_cipherCtx) {
      EVP_CIPHER_CTX_cleanup(_cipherCtx);
    }
    delete _cipherCtx;
  }

  EVP_CIPHER_CTX* getCipherContext() const
  {
    return _cipherCtx;
  }

  // enc == 1: encryption
  // enc == 0: decryption
  void init(const unsigned char* key, size_t keyLength, int enc)
  {
    if(_cipherCtx) {
      EVP_CIPHER_CTX_cleanup(_cipherCtx);
    }
    delete _cipherCtx;
    _cipherCtx = new EVP_CIPHER_CTX;
    EVP_CIPHER_CTX_init(_cipherCtx);

    if(!EVP_CipherInit_ex(_cipherCtx, EVP_rc4(), 0, 0, 0, enc)) {
      handleError();
    }
    if(!EVP_CIPHER_CTX_set_key_length(_cipherCtx, keyLength)) {
      handleError();
    }
    if(!EVP_CipherInit_ex(_cipherCtx, 0, 0, key, 0, -1)) {
      handleError();
    }
  }
  
};

} // namespace aria2

#endif // _D_LIBSSL_ARC4_CONTEXT_H_