MikkelSchubert / adapterremoval / #117

// SPDX-License-Identifier: GPL-3.0-or-later

// SPDX-FileCopyrightText: 2017 Mikkel Schubert <mikkelsch@gmail.com>

#pragma once

#include "linereader.hpp" // for line_reader_base

#include <cstddef>        // for size_t

#include <memory>         // for unique_ptr

#include <string>         // for string

#include <vector>         // for vector

namespace adapterremoval {

/**

 * Multi-file line-reader

 *

 * Wrapper around line_reader that automatically reads through one or more

 * files, returning the content as a contiguous stream of lines. No assumptions

 * are made about the format of the individual files.

 */

class joined_line_readers : public line_reader_base

{

public:

  /** Creates line-reader over multiple files in the specified order. */

  explicit joined_line_readers(const std::vector<std::string>& filenames);

   * Reads a line from the currently open file; if EOF is encountered, the

   * currently open file is closed and the next file is opened. Returns true

   * if a line was successfully read, or false if no files remain.

   */

  bool getline(std::string& dst) override;

  /** Currently open file; empty if no file is open. */

  const std::string& filename() const { return m_filename; }

  size_t linenumber() const { return m_current_line; }

  joined_line_readers(joined_line_readers&&) = delete;

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

  joined_line_readers& operator=(joined_line_readers&&) = delete;

private:

  /**

   * Open the next file, removes it from the queue, and returns true; returns

   * false if no files remain to be processed.

   */

  bool open_next_file();

  //! Files left to read; stored in reverse order.

  std::vector<std::string> m_filenames{};

  //! Currently open file, if any.

  std::unique_ptr<line_reader> m_reader{};

  //! The currently open file

  std::string m_filename{};

  //! Current line across all files.

  size_t m_current_line = 0;

};

} // namespace adapterremoval