CryptoBuf.h

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/*
  * Copyright 2010-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License").
  * You may not use this file except in compliance with the License.
  * A copy of the License is located at
  *
  *  http://aws.amazon.com/apache2.0
  *
  * or in the "license" file accompanying this file. This file 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.
  */
#pragma once

#include <aws/core/utils/crypto/Cipher.h>
#include <aws/core/Core_EXPORTS.h>
#include <ios>

namespace Aws
{
    namespace Utils
    {
        namespace Crypto
        {
            typedef std::mbstate_t FPOS_TYPE;
            static const size_t DEFAULT_BUF_SIZE = 1024;
            static const size_t PUT_BACK_SIZE = 1;

            enum class CipherMode
            {
                Encrypt,
                Decrypt
            };

            class AWS_CORE_API CryptoBuf : public std::streambuf
            {
            public:
                CryptoBuf() = default;
                virtual ~CryptoBuf() = default;
                CryptoBuf(const CryptoBuf&) = delete;
                CryptoBuf(CryptoBuf&& rhs) = delete;
                virtual void Finalize() {}
            };

            class AWS_CORE_API SymmetricCryptoBufSrc : public CryptoBuf
            {
            public:
                SymmetricCryptoBufSrc(Aws::IStream& stream, SymmetricCipher& cipher, CipherMode cipherMode, size_t bufferSize = DEFAULT_BUF_SIZE);

                SymmetricCryptoBufSrc(const SymmetricCryptoBufSrc&) = delete;
                SymmetricCryptoBufSrc(SymmetricCryptoBufSrc&&) = delete;

                SymmetricCryptoBufSrc& operator=(const SymmetricCryptoBufSrc&) = delete;
                SymmetricCryptoBufSrc& operator=(SymmetricCryptoBufSrc&&) = delete;

                virtual ~SymmetricCryptoBufSrc() { FinalizeCipher(); }

                void Finalize() override { FinalizeCipher(); }

            protected:
                pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which = std::ios_base::in | std::ios_base::out ) override;
                pos_type seekpos(pos_type pos, std::ios_base::openmode which = std::ios_base::in | std::ios_base::out ) override;

            private:
                int_type underflow() override;
                off_type ComputeAbsSeekPosition(off_type, std::ios_base::seekdir,  std::fpos<FPOS_TYPE>);
                void FinalizeCipher();

                CryptoBuffer m_isBuf;
                SymmetricCipher& m_cipher;
                Aws::IStream& m_stream;
                CipherMode m_cipherMode;
                bool m_isFinalized;
                size_t m_bufferSize;
                size_t m_putBack;
            };

            class AWS_CORE_API SymmetricCryptoBufSink : public CryptoBuf
            {
            public:
                SymmetricCryptoBufSink(Aws::OStream& stream, SymmetricCipher& cipher, CipherMode cipherMode, size_t bufferSize = DEFAULT_BUF_SIZE);
                SymmetricCryptoBufSink(const SymmetricCryptoBufSink&) = delete;
                SymmetricCryptoBufSink(SymmetricCryptoBufSink&&) = delete;

                SymmetricCryptoBufSink& operator=(const SymmetricCryptoBufSink&) = delete;
                SymmetricCryptoBufSink& operator=(SymmetricCryptoBufSink&&) = delete;

                virtual ~SymmetricCryptoBufSink();

                void FinalizeCiphersAndFlushSink();
                void Finalize() override { FinalizeCiphersAndFlushSink(); }

            private:
                int_type overflow(int_type ch) override;
                int sync() override;
                bool writeOutput(bool finalize);

                CryptoBuffer m_osBuf;
                SymmetricCipher& m_cipher;
                Aws::OStream& m_stream;
                CipherMode m_cipherMode;
                bool m_isFinalized;
                size_t m_bufferSize;
            };
        }
    }
}