slice.hpp

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/*
 * Copyright (C) 2011-2019 Daniel Scharrer
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the author(s) be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

#ifndef INNOEXTRACT_STREAM_SLICE_HPP
#define INNOEXTRACT_STREAM_SLICE_HPP

#include <ios>
#include <string>

#include <boost/iostreams/concepts.hpp>
#include <boost/filesystem/path.hpp>

#include "util/fstream.hpp"

namespace stream {

struct slice_error : public std::ios_base::failure {
  
  explicit slice_error(const std::string & msg) : std::ios_base::failure(msg) { }
  
};

class slice_reader : public boost::iostreams::source {
  
  typedef boost::filesystem::path path_type;
  
  // Information for reading embedded setup data
  const boost::uint32_t data_offset;
  
  // Information for eading external setup data
  path_type    dir;             
  std::string  base_file;       
  std::string  base_file2;      
  const size_t slices_per_disk; 
  
  // Information about the current slice
  size_t          current_slice; 
  boost::uint32_t slice_size;    
  
  // Streams
  util::ifstream ifs; 
  std::istream * is;  
  
  void seek(size_t slice);
  bool open_file(const path_type & file);
  bool open_file_case_insensitive(const path_type & dirname, const path_type & filename);
  void open(size_t slice);
  
public:
  
  static std::string slice_filename(const std::string & basename, size_t slice,
                                    size_t slices_per_disk = 1);
  
  slice_reader(std::istream * istream, boost::uint32_t offset);
  
  slice_reader(const path_type & dirname, const std::string & basename, const std::string & basename2,
               size_t disk_slice_count);
  
  bool seek(size_t slice, boost::uint32_t offset);
  
  std::streamsize read(char * buffer, std::streamsize bytes);
  
  size_t slice() { return current_slice; }
  
  bool is_open() { return (is != &ifs || ifs.is_open()); }
  
};

} // namespace stream

#endif // INNOEXTRACT_STREAM_SLICE_HPP