serializer.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 COMMON_SERIALIZER_H
#define COMMON_SERIALIZER_H

#include "common/stream.h"
#include "common/str.h"
#include "common/data-io.h"

namespace Common {

#define VER(x) Common::Serializer::Version(x)

#define SYNC_AS(SUFFIX,TYPE,SIZE) \
    template<typename T> \
    void syncAs ## SUFFIX(T &val, Version minVersion = 0, Version maxVersion = kLastVersion) { \
        if (_version < minVersion || _version > maxVersion) \
            return; \
        if (_loadStream) \
            val = static_cast<T>(_loadStream->read ## SUFFIX()); \
        else { \
            TYPE tmp = val; \
            _saveStream->write ## SUFFIX(tmp); \
        } \
        _bytesSynced += SIZE; \
    }

#define SYNC_PRIMITIVE(suffix) \
    template <typename T> \
    static inline void suffix(Serializer &s, T &value) { \
        s.syncAs##suffix(value); \
    }

class Serializer {
public:
    typedef uint32 Version;
    static const Version kLastVersion = 0xFFFFFFFF;

    SYNC_PRIMITIVE(Uint32LE)
    SYNC_PRIMITIVE(Uint32BE)
    SYNC_PRIMITIVE(Sint32LE)
    SYNC_PRIMITIVE(Sint32BE)
    SYNC_PRIMITIVE(FloatLE)
    SYNC_PRIMITIVE(FloatBE)
    SYNC_PRIMITIVE(DoubleLE)
    SYNC_PRIMITIVE(DoubleBE)
    SYNC_PRIMITIVE(Uint16LE)
    SYNC_PRIMITIVE(Uint16BE)
    SYNC_PRIMITIVE(Sint16LE)
    SYNC_PRIMITIVE(Sint16BE)
    SYNC_PRIMITIVE(Byte)
    SYNC_PRIMITIVE(SByte)

protected:
    SeekableReadStream *_loadStream;
    WriteStream *_saveStream;

    uint _bytesSynced;

    Version _version;

public:
    Serializer(SeekableReadStream *in, WriteStream *out)
        : _loadStream(in), _saveStream(out), _bytesSynced(0), _version(0) {
        assert(in || out);
    }
    virtual ~Serializer() {}

    inline bool isSaving() { return (_saveStream != 0); }
    inline bool isLoading() { return (_loadStream != 0); }

    SYNC_AS(Byte, byte, 1)
    SYNC_AS(SByte, int8, 1)

    SYNC_AS(Uint16LE, uint16, 2)
    SYNC_AS(Uint16BE, uint16, 2)
    SYNC_AS(Sint16LE, int16, 2)
    SYNC_AS(Sint16BE, int16, 2)

    SYNC_AS(Uint32LE, uint32, 4)
    SYNC_AS(Uint32BE, uint32, 4)
    SYNC_AS(Sint32LE, int32, 4)
    SYNC_AS(Sint32BE, int32, 4)
    SYNC_AS(FloatLE, float, 4)
    SYNC_AS(FloatBE, float, 4)

    SYNC_AS(DoubleLE, double, 8)
    SYNC_AS(DoubleBE, double, 8)

    
    bool err() const {
        if (_saveStream)
            return _saveStream->err();
        else
            return _loadStream->err();
    }

    void clearErr() {
        if (_saveStream)
            _saveStream->clearErr();
        else
            _loadStream->clearErr();
    }

    bool syncVersion(Version currentVersion) {
        _version = currentVersion;
        syncAsUint32LE(_version);
        return _version <= currentVersion;
    }

    Version getVersion() const { return _version; }

    void setVersion(Version version) { _version = version; }

    uint bytesSynced() const { return _bytesSynced; }

    void skip(uint32 size, Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return; // Ignore anything which is not supposed to be present in this save game version

        _bytesSynced += size;
        if (isLoading())
            _loadStream->skip(size);
        else {
            while (size--)
                _saveStream->writeByte(0);
        }
    }

    void syncBytes(byte *buf, uint32 size, Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return; // Ignore anything which is not supposed to be present in this save game version

        if (isLoading())
            _loadStream->read(buf, size);
        else
            _saveStream->write(buf, size);
        _bytesSynced += size;
    }

    bool matchBytes(const char *magic, byte size, Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return true; // Ignore anything which is not supposed to be present in this save game version

        bool match;
        if (isSaving()) {
            _saveStream->write(magic, size);
            match = true;
        } else {
            char buf[256];
            _loadStream->read(buf, size);
            match = (0 == memcmp(buf, magic, size));
        }
        _bytesSynced += size;
        return match;
    }

    void syncString(String &str, Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return; // Ignore anything which is not supposed to be present in this save game version

        if (isLoading()) {
            char c;
            str.clear();
            while ((c = _loadStream->readByte())) {
                str += c;
                _bytesSynced++;
            }
            _bytesSynced++;
        } else {
            _saveStream->writeString(str);
            _saveStream->writeByte(0);
            _bytesSynced += str.size() + 1;
        }
    }

    void syncString32(U32String &str, Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return; // Ignore anything which is not supposed to be present in this save game version

        uint32 len = str.size();

        syncAsUint32LE(len);

        if (isLoading()) {
            U32String::value_type *sl = new U32String::value_type[len];
            for (uint i = 0; i < len; i++)
                syncAsUint32LE(sl[i]);
            str = U32String(sl, len);
            delete[] sl;
        } else {
            for (uint i = 0; i < len; i++)
                _saveStream->writeUint32LE(str[i]);
            _bytesSynced += 4 * len;
        }
    }

    template <typename T>
    void syncArray(T *arr, size_t entries, void (*serializer)(Serializer &, T &), Version minVersion = 0, Version maxVersion = kLastVersion) {
        if (_version < minVersion || _version > maxVersion)
            return;

        for (size_t i = 0; i < entries; ++i) {
            serializer(*this, arr[i]);
        }
    }

    template<class TDataFormat, class... T>
    void syncMultiple(const TDataFormat &dataFormat, T &...values) {
        const TDataFormat dataFormatCopy = dataFormat;  // Copy to help compiler alias analysis, parameter is const ref to ensure TDataFormat is a concrete type

        byte buffer[DataMultipleIO<TDataFormat, T...>::kMaxSize];
        const uint actualSize = DataMultipleIO<TDataFormat, T...>::computeSize(dataFormatCopy);

        if (isLoading()) {
            syncBytes(buffer, actualSize);
            DataMultipleIO<TDataFormat, T...>::decode(dataFormatCopy, buffer, values...);
        } else {
            DataMultipleIO<TDataFormat, T...>::encode(dataFormatCopy, buffer, values...);
            syncBytes(buffer, actualSize);
        }
    }

    template<class... T>
    inline void syncMultipleEndian(bool isLittle, T &...values) {
        this->syncMultiple<EndianStorageFormat, T...>(isLittle ? EndianStorageFormat::Little : EndianStorageFormat::Big, values...);
    }

    template<class... T>
    inline void syncMultipleLE(T &...values) {
        this->syncMultiple<EndianStorageFormat, T...>(EndianStorageFormat::Little, values...);
    }

    template<class... T>
    inline void syncMultipleBE(T &...values) {
        this->syncMultiple<EndianStorageFormat, T...>(EndianStorageFormat::Big, values...);
    }
};

#undef SYNC_PRIMITIVE
#undef SYNC_AS


// Mixin class / interface
// TODO: Maybe rename this to Syncable ?
class Serializable {
public:
    virtual ~Serializable() {}

    // Maybe rename this method to "syncWithSerializer" or "syncUsingSerializer" ?
    virtual void saveLoadWithSerializer(Serializer &ser) = 0;
};

} // End of namespace Common

#endif