metaengine_mergehelper.h

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/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2006-09-15
 * Description : Exiv2 library interface.
 *               Internal merge helper.
 *
 * Copyright (C) 2006-2022 by Gilles Caulier <caulier dot gilles at gmail dot com>
 * Copyright (C) 2006-2013 by Marcel Wiesweg <marcel dot wiesweg at gmx dot de>
 *
 * 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, 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.
 *
 * ============================================================ */
 
#ifndef DIGIKAM_META_ENGINE_MERGE_HELPER_H
#define DIGIKAM_META_ENGINE_MERGE_HELPER_H
 
#include "metaengine_p.h"
 
namespace Digikam
{
 
template <class Data, class Key, class KeyString, class KeyStringList = QList<KeyString> >
 
class Q_DECL_HIDDEN MetaEngineMergeHelper
{
public:
 
    KeyStringList keys;
 
public:
 
    MetaEngineMergeHelper& operator<<(const KeyString& key)
    {
        keys << key;
 
        return *this;
    }
 
    void mergeAll(const Data& src, Data& dest)
    {
        for (typename Data::const_iterator it = src.begin() ; it != src.end() ; ++it)
        {
            typename Data::iterator destIt = dest.findKey(Key(it->key()));
 
            if (destIt == dest.end())
            {
                dest.add(*it);
            }
            else
            {
                *destIt = *it;
            }
        }
    }
 
    void mergeFields(const Data& src, Data& dest)
    {
        foreach (const KeyString& keyString, keys)
        {
            Key key(keyString.latin1());
            typename Data::const_iterator it = src.findKey(key);
 
            if (it == src.end())
            {
                continue;
            }
 
            typename Data::iterator destIt = dest.findKey(key);
 
            if (destIt == dest.end())
            {
                dest.add(*it);
            }
            else
            {
                *destIt = *it;
            }
        }
    }
 
    void exclusiveMerge(const Data& src, Data& dest)
    {
        foreach (const KeyString& keyString, keys)
        {
            Key key(keyString.latin1());
            typename Data::const_iterator it = src.findKey(key);
            typename Data::iterator destIt   = dest.findKey(key);
 
            if (destIt == dest.end())
            {
                if (it != src.end())
                {
                    dest.add(*it);
                }
            }
            else
            {
                if (it == src.end())
                {
                    dest.erase(destIt);
                }
                else
                {
                    *destIt = *it;
                }
            }
        }
    }
};
 
class Q_DECL_HIDDEN ExifMetaEngineMergeHelper
    : public MetaEngineMergeHelper<Exiv2::ExifData, Exiv2::ExifKey, QLatin1String>
{
};
 
class Q_DECL_HIDDEN IptcMetaEngineMergeHelper
    : public MetaEngineMergeHelper<Exiv2::IptcData, Exiv2::IptcKey, QLatin1String>
{
};
 
#ifdef _XMP_SUPPORT_
 
class Q_DECL_HIDDEN XmpMetaEngineMergeHelper
    : public MetaEngineMergeHelper<Exiv2::XmpData, Exiv2::XmpKey, QLatin1String>
{
};
 
#endif
 
} // namespace Digikam
 
#endif // DIGIKAM_META_ENGINE_MERGE_HELPER_H