75 lines
2.4 KiB
C++
75 lines
2.4 KiB
C++
/*
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* Copyright (C) 2022 Emeric Poupon
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*
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* This file is part of LMS.
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*
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* LMS is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* LMS is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with LMS. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "ConsecutiveReleases.hpp"
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#include "database/IDb.hpp"
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#include "database/Release.hpp"
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#include "database/Session.hpp"
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#include "database/Track.hpp"
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namespace lms::recommendation::PlaylistGeneratorConstraint
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{
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ConsecutiveReleases::ConsecutiveReleases(db::IDb& db)
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: _db{ db }
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{
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}
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float ConsecutiveReleases::computeScore(const std::vector<db::TrackId>& trackIds, std::size_t trackIndex)
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{
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assert(!trackIds.empty());
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assert(trackIndex <= trackIds.size() - 1);
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const db::ReleaseId releaseId{ getReleaseId(trackIds[trackIndex]) };
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constexpr std::size_t rangeSize{ 3 }; // check up to rangeSize tracks before/after the target track
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static_assert(rangeSize > 0);
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float score{};
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for (std::size_t i{ 1 }; i < rangeSize; ++i)
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{
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if ((trackIndex >= i) && getReleaseId(trackIds[trackIndex - i]) == releaseId)
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score += (1.F / static_cast<float>(i));
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if ((trackIndex + i < trackIds.size()) && getReleaseId(trackIds[trackIndex + i]) == releaseId)
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score += (1.F / static_cast<float>(i));
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}
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return score;
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}
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db::ReleaseId ConsecutiveReleases::getReleaseId(db::TrackId trackId)
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{
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using namespace db;
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Session& dbSession{ _db.getTLSSession() };
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auto transaction{ dbSession.createReadTransaction() };
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const Track::pointer track{ Track::find(dbSession, trackId) };
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if (!track)
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return {};
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const Release::pointer release{ track->getRelease() };
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if (!release)
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return {};
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return release->getId();
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}
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} // namespace lms::recommendation::PlaylistGeneratorConstraint
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