/* ScummVM - Scumm Interpreter * Copyright (C) 2002-2006 The ScummVM project * * 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. * * $URL$ * $Id$ * */ #ifndef SAVELOAD_H #define SAVELOAD_H #include "common/scummsys.h" #include namespace Common { class InSaveFile; class OutSaveFile; } namespace Scumm { /** * The current savegame format version. * Our save/load system uses an elaborate scheme to allow us to modify the * savegame while keeping full backward compatibility, in the sense that newer * ScummVM versions always are able to load old savegames. * In order to achieve that, we store a version in the savegame files, and whenever * the savegame layout is modified, the version is incremented. * * This roughly works by marking each savegame entry with a range of versions * for which it is valid; the save/load code iterates over all entries, but * only saves/loads those which are valid for the version of the savegame * which is being loaded/saved currently. */ #define CURRENT_VER 68 /** * An auxillary macro, used to specify savegame versions. We use this instead * of just writing the raw version, because this way they stand out more to * the reading eye, making it a bit easier to navigate through the code. */ #define VER(x) x /** * The OFFS macro essentially provides the functionality of offsetof(), that * is, it determines the offset of a struct/class member within instances of * that class. * * This is a place where we cheat a bit and sacrifice some potential portability * (although so far we haven't encountered any platform where this matters). * * To work around a warning in GCC 3.2 (and 3.1 ?) regarding non-POD types, * we use a small trick: instead of 0 we use 42. Why? Well, it seems newer GCC * versions have a heuristic built in to detect "offset-of" patterns - which is exactly * what our OFFS macro does. Now, for non-POD types this is not really legal, because * member need not be at a fixed offset relative to the variable, even if they are in * current reality (many of our complex structs are non-POD; for an explanation of * what POD means refer to or * to ) */ #define OFFS(type,item) (((ptrdiff_t)(&((type*)42)->type::item))-42) /** * Similar to the OFFS macro, this macro computes the size (in bytes) of a * member of a given struct/class type. */ #define SIZE(type,item) sizeof(((type*)42)->type::item) // Any item that is still in use automatically gets a maxVersion equal to CURRENT_VER #define MKLINE(type,item,saveas,minVer) {OFFS(type,item),saveas,SIZE(type,item),minVer,CURRENT_VER} #define MKARRAY(type,item,saveas,dim,minVer) {OFFS(type,item),128|saveas,SIZE(type,item),minVer,CURRENT_VER}, {dim,1,0,0,0} #define MKARRAY2(type,item,saveas,dim,dim2,rowlen,minVer) {OFFS(type,item),128|saveas,SIZE(type,item),minVer,CURRENT_VER}, {dim,dim2,rowlen,0,0} // Use this if you have an entry that used to be smaller: #define MKLINE_OLD(type,item,saveas,minVer,maxVer) {OFFS(type,item),saveas,SIZE(type,item),minVer,maxVer} #define MKARRAY_OLD(type,item,saveas,dim,minVer,maxVer) {OFFS(type,item),128|saveas,SIZE(type,item),minVer,maxVer}, {dim,1,0,0,0} #define MKARRAY2_OLD(type,item,saveas,dim,dim2,rowlen,minVer,maxVer) {OFFS(type,item),128|saveas,SIZE(type,item),minVer,maxVer}, {dim,dim2,rowlen,0,0} // An obsolete item/array, to be ignored upon load. We retain the type/item params to make it easier to debug. // Obsolete items have size == 0. #define MK_OBSOLETE(type,item,saveas,minVer,maxVer) {0,saveas,0,minVer,maxVer} #define MK_OBSOLETE_ARRAY(type,item,saveas,dim,minVer,maxVer) {0,128|saveas,0,minVer,maxVer}, {dim,1,0,0,0} #define MK_OBSOLETE_ARRAY2(type,item,saveas,dim,dim2,rowlen,minVer,maxVer) {0,128|saveas,0,minVer,maxVer}, {dim,dim2,rowlen,0,0} // End marker #define MKEND() {0xFFFF,0xFF,0xFF,0,0} enum { sleByte = 1, sleUint8 = 1, sleInt8 = 1, sleInt16 = 2, sleUint16 = 3, sleInt32 = 4, sleUint32 = 5 }; struct SaveLoadEntry { uint32 offs; // or: array dimension uint16 type; // or: array dimension 2 uint16 size; // or: array row length uint8 minVersion; uint8 maxVersion; }; class Serializer { public: Serializer(Common::InSaveFile *in, Common::OutSaveFile *out, uint32 savegameVersion) : _loadStream(in), _saveStream(out), _savegameVersion(savegameVersion) { } void saveLoadArrayOf(void *b, int len, int datasize, byte filetype); void saveLoadArrayOf(void *b, int num, int datasize, const SaveLoadEntry *sle); void saveLoadEntries(void *d, const SaveLoadEntry *sle); bool isSaving() { return (_saveStream != 0); } bool isLoading() { return (_loadStream != 0); } uint32 getVersion() { return _savegameVersion; } void saveUint32(uint32 d); void saveUint16(uint16 d); void saveByte(byte b); byte loadByte(); uint16 loadUint16(); uint32 loadUint32(); void saveBytes(void *b, int len); void loadBytes(void *b, int len); protected: Common::InSaveFile *_loadStream; Common::OutSaveFile *_saveStream; uint32 _savegameVersion; void saveArrayOf(void *b, int len, int datasize, byte filetype); void loadArrayOf(void *b, int len, int datasize, byte filetype); void saveEntries(void *d, const SaveLoadEntry *sle); void loadEntries(void *d, const SaveLoadEntry *sle); }; // Mixin class / interface. Maybe call it ISerializable or SerializableMixin ? class Serializable { public: virtual ~Serializable() {} virtual void saveLoadWithSerializer(Serializer *ser) = 0; }; } // End of namespace Scumm #endif