savegame.h

/* 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 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 LASTEXPRESS_SAVELOAD_H
#define LASTEXPRESS_SAVELOAD_H

/*
    Savegame format
    ---------------

    header: 32 bytes
        uint32 {4}      - signature: 0x12001200
        uint32 {4}      - chapter - needs to be [0; 5]
        uint32 {4}      - time - needs to be >= 32 [1061100; timeMax]
        uint32 {4}      - ?? needs to be >= 32
        uint32 {4}      - ?? needs to be = 1
        uint32 {4}      - Brightness (needs to be [0-6])
        uint32 {4}      - Volume (needs to be [0-7])
        uint32 {4}      - ?? needs to be = 9

    Game data Format
    -----------------

    uint32 {4}        - entity
    uint32 {4}        - current time
    uint32 {4}        - time delta (how much a tick is in "real" time)
    uint32 {4}        - time ticks
    uint32 {4}        - scene Index               max: 2500
    byte {1}          - use backup scene
    uint32 {4}        - backup Scene Index 1      max: 2500
    uint32 {4}        - backup Scene Index 2      max: 2500
    uint32 {4}        - selected inventory item   max: 32
    uint32 {4*100*10} - positions by car(BlockedView)
    uint32 {4*16}     - compartments (BlockedX)
    uint32 {4*16}     - compartments? (SoftBlockedX)
    uint32 {4*128}    - game progress
    byte {512}        - game events
    byte {7*32}       - inventory
    byte {5*128}      - objects
    byte {1262*40}    - entities (characters and train entities)

    uint32 {4}        - sound queue state
    uint32 {4}        - ??
    uint32 {4}        - number of sound entries
    byte {count*68}   - sound entries

    byte {16*128}     - save point data
    uint32 {4}        - number of save points (max: 128)
    byte {count*16}   - save points

    ... more unknown stuff

*/

#include "lastexpress/shared.h"

#include "common/savefile.h"
#include "common/serializer.h"
#include "common/memstream.h"

#include "engines/savestate.h"

namespace LastExpress {

// our own hack until compression code will be confirmed stable
#define DISABLE_COMPRESSION 1

// Savegame signatures
#define SAVEGAME_SIGNATURE       (0x12001200 ^ DISABLE_COMPRESSION)    // 301994496
#define SAVEGAME_ENTRY_SIGNATURE 0xE660E660    // 3865110112

#define WRAP_SYNC_FUNCTION(instance, className, method) \
    new Common::Functor1Mem<Common::Serializer &, void, className>(instance, &className::method)

class LastExpressEngine;

class SavegameStream : public Common::MemoryWriteStreamDynamic, public Common::SeekableReadStream {
public:
    SavegameStream() : MemoryWriteStreamDynamic(DisposeAfterUse::YES), _eos(false) {
        _enableCompression = false;
        _bufferOffset = -1;
        _valueCount = 0;
        _previousValue = 0;
        _repeatCount = 0;
        _offset = 0;
        _status = kStatusReady;

        memset(_buffer, 0, 256);
    }

    int64 pos() const override { return MemoryWriteStreamDynamic::pos(); }
    int64 size() const override { return MemoryWriteStreamDynamic::size(); }
    bool seek(int64 offset, int whence = SEEK_SET) override { return MemoryWriteStreamDynamic::seek(offset, whence); }
    bool eos() const override { return _eos; }
    uint32 read(void *dataPtr, uint32 dataSize) override;
    uint32 write(const void *dataPtr, uint32 dataSize) override;

    uint32 process();

private:
    enum CompressedStreamStatus {
        kStatusReady,
        kStatusReading,
        kStatusWriting
    };

    uint32 readUncompressed(void *dataPtr, uint32 dataSize);

    // Compressed data
    uint32 writeCompressed(const void *dataPtr, uint32 dataSize);
    uint32 readCompressed(void *dataPtr, uint32 dataSize);

    void writeBuffer(uint8 value, bool onlyValue = true);
    uint8 readBuffer();

private:
    bool _eos;

    // Compression handling
    bool                   _enableCompression;
    int16                  _bufferOffset;
    byte                   _valueCount;
    byte                   _previousValue;
    int16                  _repeatCount;
    uint32                 _offset;
    CompressedStreamStatus _status;

    byte _buffer[256];
};

class SaveLoad {
public:
    static const int kMaximumSaveSlots = 6; // blue, red, green, purple, teal, gold

    SaveLoad(LastExpressEngine *engine);
    ~SaveLoad();

    // Init
    void create(const Common::String &target, GameId id);
    void clear(bool clearStream = false);
    uint32 init(const Common::String &target, GameId id, bool resetHeaders);

    // Save & Load
    void loadLastGame();
    void loadGame(uint32 index);
    void saveGame(SavegameType type, EntityIndex entity, uint32 value);

    void loadVolumeBrightness();
    void saveVolumeBrightness();

    static SaveStateList list(const MetaEngine *metaEngine, const Common::String &target);
    static bool remove(const Common::String &target, GameId slot);

    // Opening save files
    static Common::String getFilename(const Common::String &target, GameId slot);
    static Common::InSaveFile *openForLoading(const Common::String &target, GameId slot);
    static Common::OutSaveFile *openForSaving(const Common::String &target, GameId slot);

    // Getting information
    static bool isSavegamePresent(const Common::String &target, GameId id);
    static bool isSavegameValid(const Common::String &target, GameId id);

    bool isGameFinished(uint32 menuIndex, uint32 savegameIndex);

    // Accessors
    uint32       getTime(uint32 index) { return getEntry(index)->time; }
    ChapterIndex getChapter(uint32 index) { return getEntry(index)->chapter; }
    uint32       getValue(uint32 index) { return getEntry(index)->value; }
    uint32       getLastSavegameTicks() const { return _gameTicksLastSavegame; }

private:
    LastExpressEngine *_engine;

    struct SavegameMainHeader : Common::Serializable {
        uint32 signature;
        uint32 count;
        uint32 offset;
        uint32 offsetEntry;
        uint32 keepIndex;
        int32 brightness;
        int32 volume;
        uint32 field_1C;

        SavegameMainHeader() {
            signature = SAVEGAME_SIGNATURE;
            count = 0;
            offset = 32;
            offsetEntry = 32;
            keepIndex = 0;
            brightness = 3;
            volume = 7;
            field_1C = 9; // Note: In demo's original save "BLUE.EGG" this value is 0x19
        }

        void saveLoadWithSerializer(Common::Serializer &s) override {
            s.syncAsUint32LE(signature);
            s.syncAsUint32LE(count);
            s.syncAsUint32LE(offset);
            s.syncAsUint32LE(offsetEntry);
            s.syncAsUint32LE(keepIndex);
            s.syncAsUint32LE(brightness);
            s.syncAsUint32LE(volume);
            s.syncAsUint32LE(field_1C);
        }

        bool isValid() {
            if (signature != SAVEGAME_SIGNATURE)
                return false;

            /* Check not needed as it can never be < 0
            if (header.chapter < 0)
                return false;*/

            if (offset < 32)
                return false;

            if (offsetEntry < 32)
                return false;

            if (keepIndex != 1 && keepIndex != 0)
                return false;

            if (brightness < 0 || brightness > 6)
                return false;

            if (volume < 0 || volume > 7)
                return false;

            if (field_1C != 9)
                return false;

            return true;
        }
    };

    struct SavegameEntryHeader : Common::Serializable {
        uint32 signature;
        SavegameType type;
        uint32 time;
        int offset;
        ChapterIndex chapter;
        uint32 value;
        int field_18;
        int field_1C;

        SavegameEntryHeader() {
            signature = SAVEGAME_ENTRY_SIGNATURE;
            type = kSavegameTypeIndex;
            time = kTimeNone;
            offset = 0;
            chapter = kChapterAll;
            value = 0;
            field_18 = 0;
            field_1C = 0;
        }

        void saveLoadWithSerializer(Common::Serializer &s) override {
            s.syncAsUint32LE(signature);
            s.syncAsUint32LE(type);
            s.syncAsUint32LE(time);
            s.syncAsUint32LE(offset);
            s.syncAsUint32LE(chapter);
            s.syncAsUint32LE(value);
            s.syncAsUint32LE(field_18);
            s.syncAsUint32LE(field_1C);
        }

        bool isValid() {
            if (signature != SAVEGAME_ENTRY_SIGNATURE)
                return false;

            if (type < kSavegameTypeTime || type > kSavegameTypeTickInterval)
                return false;

            if (time < kTimeStartGame || time > kTimeCityConstantinople)
                return false;

            if (offset <= 0 || offset & 0xF)
                return false;

            /* No check for < 0, as it cannot happen normaly */
            if (chapter == 0)
                return false;

            return true;
        }
    };

    SavegameStream *_savegame;
    Common::Array<SavegameEntryHeader *> _gameHeaders;
    uint32 _gameTicksLastSavegame;

    // Headers
    static bool loadMainHeader(Common::InSaveFile *stream, SavegameMainHeader *header);

    // Entries
    void writeEntry(SavegameType type, EntityIndex entity, uint32 val);
    void readEntry(SavegameType *type, EntityIndex *entity, uint32 *val, bool keepIndex);

    uint32 writeValue(Common::Serializer &ser, const char *name, Common::Functor1<Common::Serializer &, void> *function, uint size);
    uint32 readValue(Common::Serializer &ser, const char *name, Common::Functor1<Common::Serializer &, void> *function, uint size = 0);

    SavegameEntryHeader *getEntry(uint32 index);

    // Savegame stream
    void initStream();
    void loadStream(const Common::String &target, GameId id);
    void flushStream(const Common::String &target, GameId id);

    // Misc
    EntityIndex _entity;
    void syncEntity(Common::Serializer &ser);
};

} // End of namespace LastExpress

#endif // LASTEXPRESS_SAVELOAD_H