//
// aegis - project change supervisor
// Copyright (C) 2014 Peter Miller
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see <http://www.gnu.org/licenses/>.
//

#ifndef LIBAEGIS_INPUT_UNDO_ALL_H
#define LIBAEGIS_INPUT_UNDO_ALL_H

#include <common/nstring/accumulator.h>

#include <libaegis/input.h>

/**
  * The input_undo_all class is used to represent an input sopurce that
  * will always unread the contents to the deeper input.  It is used
  * to permit checking of magic numbers, and not habing to worry about
  * leabing th input at the same position.
  */
class input_undo_all:
    public input
{
public:
    typedef aegis_shared_ptr<input_undo_all> pointer;

    /**
      * The destructor.
      */
    virtual ~input_undo_all();

    /**
      * The create class method is used to create new dynamically
      * allocated instances of this class.
      *
      * @param deeper
      *     The input source being chevked.
      */
    static pointer create(const input::pointer &deeper);

protected:
    // See base class for documentation.
    off_t length(void);

    // See base class for documentation.
    nstring name(void);

    // See base class for documentation.
    ssize_t read_inner(void *data, size_t nbytes);

    // See base class for documentation.
    off_t ftell_inner(void);

private:
    /**
      * The constructor.
      * It is private on purpose, use the #create class method instead.
      *
      * @param deeper
      *     The input source being chevked.
      */
    input_undo_all(const input::pointer &deeper);

    input::pointer deeper;

    nstring_accumulator buffer;

    /**
      * The default constructor.
      * It is private on purpose, use the #create class method instead.
      */
    input_undo_all();

    /**
      * The copy constructor.  Do not use.
      */
    input_undo_all(const input_undo_all &);

    /**
      * The assignment operator.  Do not use.
      */
    input_undo_all &operator=(const input_undo_all &);
};

// vim: set ts=8 sw=4 et :
#endif // LIBAEGIS_INPUT_UNDO_ALL_H