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Diffstat (limited to 'engines/sci/engine/file.h')
-rw-r--r-- | engines/sci/engine/file.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/engines/sci/engine/file.h b/engines/sci/engine/file.h new file mode 100644 index 0000000000..e7b1090c91 --- /dev/null +++ b/engines/sci/engine/file.h @@ -0,0 +1,75 @@ +/* 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 |