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include/utils/encrypting_reader.hpp

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+/*
+  Copyright <2018-2022> <scott.e.graves@protonmail.com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
+  associated documentation files (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge, publish, distribute,
+  sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all copies or
+  substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
+  NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
+  OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+#ifndef INCLUDE_UTILS_ENCRYPTING_READER_HPP_
+#define INCLUDE_UTILS_ENCRYPTING_READER_HPP_
+
+#include "common.hpp"
+#include "utils/file_utils.hpp"
+
+namespace repertory::utils::encryption {
+class encrypting_reader final {
+public:
+  encrypting_reader(const std::string &file_name, const std::string &source_path,
+                    const bool &stop_requested, const std::string &token,
+                    const size_t error_return = 0);
+
+  encrypting_reader(const encrypting_reader &r);
+
+  ~encrypting_reader();
+
+public:
+  typedef std::basic_iostream<char, std::char_traits<char>> iostream;
+  typedef std::basic_streambuf<char, std::char_traits<char>> streambuf;
+
+private:
+  const CryptoPP::SecByteBlock key_;
+  const bool &stop_requested_;
+  const size_t error_return_;
+  std::unordered_map<std::size_t, std::vector<char>> chunk_buffers_;
+  std::string encrypted_file_name_;
+  std::size_t last_data_chunk_ = 0u;
+  std::size_t last_data_chunk_size_ = 0u;
+  std::uint64_t read_offset_ = 0u;
+  native_file_ptr source_file_;
+  std::uint64_t total_size_ = 0u;
+
+private:
+  static const std::size_t header_size_;
+  static const std::size_t data_chunk_size_;
+  static const std::size_t encrypted_chunk_size_;
+
+private:
+  size_t reader_function(char *buffer, size_t size, size_t nitems);
+
+public:
+  static std::uint64_t calculate_decrypted_size(const std::uint64_t &total_size);
+
+  std::shared_ptr<iostream> create_iostream() const;
+
+  static constexpr const std::size_t &get_encrypted_chunk_size() { return encrypted_chunk_size_; }
+
+  static constexpr const std::size_t &get_data_chunk_size() { return data_chunk_size_; }
+
+  std::string get_encrypted_file_name() const { return encrypted_file_name_; }
+
+  std::size_t get_error_return() const { return error_return_; }
+
+  static constexpr const std::size_t &get_header_size() { return header_size_; }
+
+  const bool &get_stop_requested() const { return stop_requested_; }
+
+  std::uint64_t get_total_size() const { return total_size_; }
+
+  static size_t reader_function(char *buffer, size_t size, size_t nitems, void *instream) {
+    return reinterpret_cast<encrypting_reader *>(instream)->reader_function(buffer, size, nitems);
+  }
+
+  void set_read_position(const std::uint64_t &position) { read_offset_ = position; }
+};
+} // namespace repertory::utils::encryption
+
+#endif // INCLUDE_UTILS_ENCRYPTING_READER_HPP_