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include/download/buffered_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_DOWNLOAD_BUFFERED_READER_HPP_
+#define INCLUDE_DOWNLOAD_BUFFERED_READER_HPP_
+
+#include "common.hpp"
+#include "types/repertory.hpp"
+
+namespace repertory {
+class app_config;
+class buffered_reader final {
+public:
+  buffered_reader(const app_config &config, const filesystem_item &fsi,
+                  const api_reader_callback &api_reader, const std::size_t &chunk_size,
+                  const std::size_t &total_chunks, const std::size_t &start_chunk);
+
+  ~buffered_reader();
+
+private:
+  const filesystem_item &fsi_;
+  const api_reader_callback &api_reader_;
+  const std::size_t chunk_size_;
+  const std::size_t total_chunks_;
+  boost::dynamic_bitset<> ring_state_;
+
+  api_error error_ = api_error::success;
+  std::unique_ptr<std::vector<char>> first_chunk_data_;
+  std::unique_ptr<std::vector<char>> last_chunk_data_;
+  std::size_t read_chunk_index_ = 0u;
+  std::mutex read_mutex_;
+  std::condition_variable read_notify_;
+  std::size_t read_offset_ = 0u;
+  bool reset_reader_ = false;
+  std::vector<std::vector<char>> ring_data_;
+  std::unique_ptr<std::thread> reader_thread_;
+  bool stop_requested_ = false;
+  std::mutex write_mutex_;
+  std::size_t write_chunk_index_ = 0u;
+
+private:
+  bool is_active() const { return not stop_requested_ && (error_ == api_error::success); }
+
+  void reader_thread();
+
+public:
+  std::size_t get_chunk_size() const { return chunk_size_; }
+
+  void get_first_chunk(std::vector<char> *&data) { data = first_chunk_data_.get(); }
+
+  void get_last_chunk(std::vector<char> *&data) { data = last_chunk_data_.get(); }
+
+  bool has_first_chunk() const { return static_cast<bool>(first_chunk_data_); }
+
+  bool has_last_chunk() const { return static_cast<bool>(last_chunk_data_); }
+
+  void notify_stop_requested();
+
+  api_error read_chunk(const std::size_t &chunk_index, std::vector<char> &data);
+};
+} // namespace repertory
+
+#endif // INCLUDE_DOWNLOAD_BUFFERED_READER_HPP_