file.hpp

/*

Copyright (c) 2002-2005, Yauheni Akhotnikau
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.

- The name of the author may not be used to endorse or promote products derived
from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.

*/

#if !defined( _OESS_1__FILE__FILE_HPP_ )
#define _OESS_1__FILE__FILE_HPP_

#include <oess_1/file/h/declspec.hpp>

#include <auto_ptr_3/h/vect_ptr.hpp>

#include <oess_1/io/h/binstream.hpp>

namespace oess_1 {

namespace file {

//
// file_t
//

class OESS_1__FILE__TYPE  file_t :
  public oess_1::io::ibinstream_t,
  public oess_1::io::obinstream_t
{
  public :
    file_t();
    virtual ~file_t();

    void
    open(
      const std::string & file_name,
      bool is_read_only );

    void
    create(
      const std::string & file_name );

    void
    close();

    oess_1::uint_t
    tell();

    void
    seek( oess_1::uint_t pos );

    oess_1::uint_t
    length();

    virtual bool
    eof() const;

    void
    chsize(
      oess_1::uint_t size );

    static void
    remove( const std::string & file_name );

    static bool
    is_file_exists(
      const std::string & file_name );

    static void
    rename_file(
      const std::string & what,
      const std::string & to,
      bool auto_destroy_existing_target = false );

  protected :
    /*
      ВНИМАНИЕ!
      В реализации класса file_t используется
      тот факт, что любая операция ввода/вывода
      использует парные вызовы in_reserve/in_shift
      (out_reserve/out_shift).
      Поэтому метод in_reserve осуществляет загрузку
      требуемого фрагмента в память. Метод out_shift
      осуществляет запись фрагмента в файл.
      Т.е. содержимое считываемого/записываемого
      фрагмента является актуальным во внутреннем буфере
      класса file_t только между вызовами *_reserve/ *_shift.
      В остальное время буфер считается незаполненым.
    */

    virtual const oess_1::char_t *
    in_reserve(
      size_t item_count,
      size_t item_size,
      size_t & item_available );

    virtual void
    in_shift(
      size_t item_count,
      size_t item_size );

    virtual oess_1::char_t *
    out_reserve(
      size_t item_count,
      size_t item_size,
      size_t & item_available );

    virtual void
    out_shift(
      size_t item_count,
      size_t item_size );

  private :
    auto_ptr_3::vect_ptr_t< oess_1::char_t >  m_buf;

    int m_file;
    bool  m_is_read_only;

    void
    is_workable(
      bool is_read_only_op ) const;
};

} 
} 
#endif

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