resource_patcher.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 SCI_RESOURCE_RESOURCE_PATCHER_H
#define SCI_RESOURCE_RESOURCE_PATCHER_H

#include "common/language.h"
#include "sci/sci.h"
#include "sci/resource/resource.h"
#include "sci/resource/resource_intern.h"

namespace Sci {

enum ResourcePatchOp {
    // Using high bytes to make it less likely that accidental raw data will be
    // treated like an operator instead of an error
    kSkipBytes = 0xF0,
    kReplaceBytes,
    kInsertBytes,
    kReplaceNumber,
    kAdjustNumber,
    kInsertNumber,
    kReplaceFill,
    kInsertFill,
    kEndOfPatch
};

enum SciMedia : uint;

struct GameResourcePatch {
    SciGameId gameId;

    SciMedia media;

    Common::Language gameLanguage;

    ResourceType resourceType;

    uint16 resourceNumber;

    const byte *patchData;

    bool isNewResource;
};

class ResourcePatcher : public ResourceSource {
public:
    ResourcePatcher(const SciGameId gameId, const bool isCD, const Common::Platform platform, const Common::Language gameLanguage);

    ~ResourcePatcher() override {}

    bool applyPatch(Resource &resource) const;

    void scanSource(ResourceManager *resMan) override;

    void loadResource(ResourceManager *resMan, Resource *res) override {}

private:
    struct PatchSizes {
        uint32 expected;

        int32 delta;

        PatchSizes(uint32 exp, int32 d) {
            expected = exp;
            delta = d;
        }
    };

    typedef Common::Array<GameResourcePatch> PatchList;

    PatchList _patches;

    void patchResource(Resource &resource, const GameResourcePatch &patch) const;

    PatchSizes calculatePatchSizes(const byte *patchData) const;

    int32 readBlockSize(const byte * &patchData) const;
};
} // End of namespace Sci

#endif  // SCI_RESOURCE_RESOURCE_PATCHER_H