CipherStream.h

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/*
 * CipherStream.h
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef CIPHERSTREAM_H_
#define CIPHERSTREAM_H_

#include "ibrcommon/Exceptions.h"
#include <streambuf>
#include <iostream>
#include <vector>

namespace ibrcommon
{
        class CipherStream : public std::basic_streambuf<char, std::char_traits<char> >, public std::ostream
        {
        public:
                enum CipherMode
                {
                        CIPHER_ENCRYPT = 0,
                        CIPHER_DECRYPT = 1
                };

                CipherStream(std::ostream &stream, const CipherMode mode = CIPHER_DECRYPT, const size_t buffer = 2048);
                virtual ~CipherStream();

                void encrypt(std::iostream& stream);

                void decrypt(std::iostream& stream);

        protected:
                virtual void encrypt(char *buf, const size_t size) = 0;
                virtual void decrypt(char *buf, const size_t size) = 0;
                virtual void encrypt_final() {};
                virtual void decrypt_final() {};

                virtual int sync();
                virtual std::char_traits<char>::int_type overflow(std::char_traits<char>::int_type = std::char_traits<char>::eof());

                CipherMode _mode;

        private:
                std::ostream &_stream;

                // Output buffer
                std::vector<char> data_buf_;

                // length of the data buffer
                size_t data_size_;
        };
}

#endif /* CIPHERSTREAM_H_ */