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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef SCI_ENGINE_FILE_H
#define SCI_ENGINE_FILE_H
#include "common/scummsys.h"
namespace Sci {
#ifdef ENABLE_SCI32
/**
* An implementation of a virtual file that supports basic read and write
* operations simultaneously.
*
* This class has been initially implemented for Phantasmagoria, which has its
* own custom save/load code. The load code keeps checking for the existence
* of the save index file and keeps closing and reopening it for each save
* slot. This is notoriously slow and clumsy, and introduces noticeable delays,
* especially for non-desktop systems. Also, its game scripts request to open
* the index file for reading and writing with the same parameters
* (SaveManager::setCurrentSave and SaveManager::getCurrentSave). Moreover,
* the game scripts reopen the index file for writing in order to update it
* and seek within it. We do not support seeking in writeable streams, and the
* fact that our saved games are ZIP files makes this operation even more
* expensive. Finally, the savegame index file is supposed to be expanded when
* a new save slot is added.
* For the aforementioned reasons, this class has been implemented, which offers
* the basic functionality needed by the game scripts in Phantasmagoria.
*/
class VirtualIndexFile {
public:
VirtualIndexFile(Common::String fileName);
~VirtualIndexFile();
uint32 read(char *buffer, uint32 size);
uint32 readLine(char *buffer, uint32 size);
uint32 write(const char *buffer, uint32 size);
bool seek(int32 offset, int whence);
void close();
private:
char *_buffer;
uint32 _bufferSize;
char *_ptr;
Common::String _fileName;
bool _changed;
};
#endif
} // End of namespace Sci
#endif // SCI_ENGINE_FILE_H
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