void CMusicInfoScanner::CategoriseAlbums(VECSONGS &songsToCheck, VECALBUMS &albums)
{
/* Step 1: categorise on the album name */
map<string, vector<CSong *> > albumNames;
for (VECSONGS::iterator i = songsToCheck.begin(); i != songsToCheck.end(); ++i)
albumNames[i->strAlbum].push_back(&(*i));
/*
Step 2: Split into unique albums based on album name and album artist
In the case where the album artist is unknown, we use the primary artist
(i.e. first artist from each song).
*/
albums.clear();
for (map<string, vector<CSong *> >::iterator i = albumNames.begin(); i != albumNames.end(); ++i)
{
// sort the songs by tracknumber to identify duplicate track numbers
vector<CSong *> &songs = i->second;
sort(songs.begin(), songs.end(), SortSongsByTrack);
// map the songs to their primary artists
bool tracksOverlap = false;
bool hasAlbumArtist = false;
map<string, vector<CSong *> > artists;
for (vector<CSong *>::iterator j = songs.begin(); j != songs.end(); ++j)
{
CSong *song = *j;
// test for song overlap
if (j != songs.begin() && song->iTrack == (*(j-1))->iTrack)
tracksOverlap = true;
// get primary artist
string primary;
if (!song->albumArtist.empty())
{
primary = song->albumArtist[0];
hasAlbumArtist = true;
}
else if (!song->artist.empty())
primary = song->artist[0];
// add to the artist map
artists[primary].push_back(song);
}
/*
We have a compilation if
1. album name is non-empty AND
2. no tracks overlap AND
3a. a unique primary artist is specified as "various" or "various artists" OR
3b. we have at least two primary artists and no album artist specified.
*/
bool compilation = !i->first.empty() && !tracksOverlap; // 1+2
if (artists.size() == 1)
{
string artist = artists.begin()->first; StringUtils::ToLower(artist);
if (!StringUtils::EqualsNoCase(artist, "various") &&
!StringUtils::EqualsNoCase(artist, "various artists")) // 3a
compilation = false;
}
else if (hasAlbumArtist) // 3b
compilation = false;
if (compilation)
{
CLog::Log(LOGDEBUG, "Album '%s' is a compilation as there's no overlapping tracks and %s", i->first.c_str(), hasAlbumArtist ? "the album artist is 'Various'" : "there is more than one unique artist");
artists.clear();
std::string various = g_localizeStrings.Get(340); // Various Artists
vector<string> va; va.push_back(various);
for (vector<CSong *>::iterator j = songs.begin(); j != songs.end(); ++j)
(*j)->albumArtist = va;
artists.insert(make_pair(various, songs));
}
/*
Step 3: Find the common albumartist for each song and assign
albumartist to those tracks that don't have it set.
*/
for (map<string, vector<CSong *> >::iterator j = artists.begin(); j != artists.end(); ++j)
{
// find the common artist for these songs
vector<CSong *> &artistSongs = j->second;
vector<string> common = artistSongs.front()->albumArtist.empty() ? artistSongs.front()->artist : artistSongs.front()->albumArtist;
for (vector<CSong *>::iterator k = artistSongs.begin() + 1; k != artistSongs.end(); ++k)
{
unsigned int match = 0;
vector<string> &compare = (*k)->albumArtist.empty() ? (*k)->artist : (*k)->albumArtist;
for (; match < common.size() && match < compare.size(); match++)
{
if (compare[match] != common[match])
break;
}
common.erase(common.begin() + match, common.end());
}
/*
Step 4: Assign the album artist for each song that doesn't have it set
and add to the album vector
*/
CAlbum album;
album.strAlbum = i->first;
album.artist = common;
album.bCompilation = compilation;
for (vector<CSong *>::iterator k = artistSongs.begin(); k != artistSongs.end(); ++k)
{
if ((*k)->albumArtist.empty())
(*k)->albumArtist = common;
album.songs.push_back(*(*k));
// TODO: in future we may wish to union up the genres, for now we assume they're the same
if (album.genre.empty())
album.genre = (*k)->genre;
// in addition, we may want to use year as discriminating for albums
if (album.iYear == 0)
album.iYear = (*k)->iYear;
}
albums.push_back(album);
}
}
}
