TextIdentificationFrame *TextIdentificationFrame::createTIPLFrame(const PropertyMap &properties) // static
{
  TextIdentificationFrame *frame = new TextIdentificationFrame("TIPL");
  StringList l;
  for(PropertyMap::ConstIterator it = properties.begin(); it != properties.end(); ++it){
    l.append(it->first);
    l.append(it->second.toString(",")); // comma-separated list of names
  }
  frame->setText(l);
  return frame;
}

String ID3v2::Tag::genre() const
{
  // TODO: In the next major version (TagLib 2.0) a list of multiple genres
  // should be separated by " / " instead of " ".  For the moment to keep
  // the behavior the same as released versions it is being left with " ".

  if(d->frameListMap["TCON"].isEmpty() ||
     !dynamic_cast<TextIdentificationFrame *>(d->frameListMap["TCON"].front()))
  {
    return String::null;
  }

  // ID3v2.4 lists genres as the fields in its frames field list.  If the field
  // is simply a number it can be assumed that it is an ID3v1 genre number.
  // Here was assume that if an ID3v1 string is present that it should be
  // appended to the genre string.  Multiple fields will be appended as the
  // string is built.

  TextIdentificationFrame *f = static_cast<TextIdentificationFrame *>(
    d->frameListMap["TCON"].front());

  StringList fields = f->fieldList();

  StringList genres;

  for(StringList::Iterator it = fields.begin(); it != fields.end(); ++it) {

    if((*it).isEmpty())
      continue;

    bool isNumber = true;

    for(String::ConstIterator charIt = (*it).begin();
        isNumber && charIt != (*it).end();
        ++charIt)
    {
      isNumber = *charIt >= '0' && *charIt <= '9';
    }

    if(isNumber) {
      int number = (*it).toInt();
      if(number >= 0 && number <= 255)
        *it = ID3v1::genre(number);
    }

    if(std::find(genres.begin(), genres.end(), *it) == genres.end())
      genres.append(*it);
  }

  return genres.toString();
}

void ID3v2::Tag::setTextFrame(const ByteVector &id, const String &value)
{
  if(value.isEmpty()) {
    removeFrames(id);
    return;
  }

  if(!d->frameListMap[id].isEmpty())
    d->frameListMap[id].front()->setText(value);
  else {
    const String::Type encoding = d->factory->defaultTextEncoding();
    TextIdentificationFrame *f = new TextIdentificationFrame(id, encoding);
    addFrame(f);
    f->setText(value);
  }
}

Frame *Frame::createTextualFrame(const String &key, const StringList &values) //static
{
  // check if the key is contained in the key<=>frameID mapping
  ByteVector frameID = keyToFrameID(key);
  if(!frameID.isNull()) {
    if(frameID[0] == 'T'){ // text frame
      TextIdentificationFrame *frame = new TextIdentificationFrame(frameID, String::UTF8);
      frame->setText(values);
      return frame;
    } else if((frameID[0] == 'W') && (values.size() == 1)){  // URL frame (not WXXX); support only one value
        UrlLinkFrame* frame = new UrlLinkFrame(frameID);
        frame->setUrl(values.front());
        return frame;
    }
  }
  if(key == "MUSICBRAINZ_TRACKID" && values.size() == 1) {
    UniqueFileIdentifierFrame *frame = new UniqueFileIdentifierFrame("http://musicbrainz.org", values.front().data(String::UTF8));
    return frame;
  }
  // now we check if it's one of the "special" cases:
  // -LYRICS: depending on the number of values, use USLT or TXXX (with description=LYRICS)
  if((key == "LYRICS" || key.startsWith(lyricsPrefix)) && values.size() == 1){
    UnsynchronizedLyricsFrame *frame = new UnsynchronizedLyricsFrame(String::UTF8);
    frame->setDescription(key == "LYRICS" ? key : key.substr(lyricsPrefix.size()));
    frame->setText(values.front());
    return frame;
  }
  // -URL: depending on the number of values, use WXXX or TXXX (with description=URL)
  if((key == "URL" || key.startsWith(urlPrefix)) && values.size() == 1){
    UserUrlLinkFrame *frame = new UserUrlLinkFrame(String::UTF8);
    frame->setDescription(key == "URL" ? key : key.substr(urlPrefix.size()));
    frame->setUrl(values.front());
    return frame;
  }
  // -COMMENT: depending on the number of values, use COMM or TXXX (with description=COMMENT)
  if((key == "COMMENT" || key.startsWith(commentPrefix)) && values.size() == 1){
    CommentsFrame *frame = new CommentsFrame(String::UTF8);
    if (key != "COMMENT"){
      frame->setDescription(key.substr(commentPrefix.size()));
    }
    frame->setText(values.front());
    return frame;
  }
  // if non of the above cases apply, we use a TXXX frame with the key as description
  return new UserTextIdentificationFrame(keyToTXXX(key), values, String::UTF8);
}

void FrameFactory::rebuildAggregateFrames(ID3v2::Tag *tag) const
{
  if(tag->header()->majorVersion() < 4 &&
     tag->frameList("TDRC").size() == 1 &&
     tag->frameList("TDAT").size() == 1)
  {
    TextIdentificationFrame *tdrc =
      static_cast<TextIdentificationFrame *>(tag->frameList("TDRC").front());
    UnknownFrame *tdat = static_cast<UnknownFrame *>(tag->frameList("TDAT").front());

    if(tdrc->fieldList().size() == 1 &&
       tdrc->fieldList().front().size() == 4 &&
       tdat->data().size() >= 5)
    {
      String date(tdat->data().mid(1), String::Type(tdat->data()[0]));
      if(date.length() == 4) {
        tdrc->setText(tdrc->toString() + '-' + date.substr(2, 2) + '-' + date.substr(0, 2));
        if(tag->frameList("TIME").size() == 1) {
          UnknownFrame *timeframe = static_cast<UnknownFrame *>(tag->frameList("TIME").front());
          if(timeframe->data().size() >= 5) {
            String time(timeframe->data().mid(1), String::Type(timeframe->data()[0]));
            if(time.length() == 4) {
              tdrc->setText(tdrc->toString() + 'T' + time.substr(0, 2) + ':' + time.substr(2, 2));
            }
          }
        }
      }
    }
  }
}

Frame *FrameFactory::createFrame(const ByteVector &data, uint version) const
{
  Frame::Header *header = new Frame::Header(data, version);
  ByteVector frameID = header->frameID();

  // A quick sanity check -- make sure that the frameID is 4 uppercase Latin1
  // characters.  Also make sure that there is data in the frame.

  if(!frameID.size() == (version < 3 ? 3 : 4) ||
     header->frameSize() <= 0 ||
     header->frameSize() > data.size())
  {
    delete header;
    return 0;
  }

  for(ByteVector::ConstIterator it = frameID.begin(); it != frameID.end(); it++) {
    if( (*it < 'A' || *it > 'Z') && (*it < '1' || *it > '9') ) {
      delete header;
      return 0;
    }
  }

  // TagLib doesn't mess with encrypted frames, so just treat them
  // as unknown frames.

#if HAVE_ZLIB == 0
  if(header->compression()) {
    debug("Compressed frames are currently not supported.");
    return new UnknownFrame(data, header);
  }
#endif
  if(header->encryption()) {
    debug("Encrypted frames are currently not supported.");
    return new UnknownFrame(data, header);
  }

  if(!updateFrame(header)) {
    header->setTagAlterPreservation(true);
    return new UnknownFrame(data, header);
  }

  // updateFrame() might have updated the frame ID.

  frameID = header->frameID();

  // This is where things get necissarily nasty.  Here we determine which
  // Frame subclass (or if none is found simply an Frame) based
  // on the frame ID.  Since there are a lot of possibilities, that means
  // a lot of if blocks.

  // Text Identification (frames 4.2)

  if(frameID.startsWith("T")) {
    TextIdentificationFrame *f = frameID != "TXXX"
      ? new TextIdentificationFrame(data, header)
      : new UserTextIdentificationFrame(data, header);

    if(d->useDefaultEncoding)
      f->setTextEncoding(d->defaultEncoding);

    if(frameID == "TCON")
      updateGenre(f);

    return f;
  }

  // Comments (frames 4.10)

  if(frameID == "COMM") {
    CommentsFrame *f = new CommentsFrame(data, header);
    if(d->useDefaultEncoding)
      f->setTextEncoding(d->defaultEncoding);
    return f;
  }

  // Attached Picture (frames 4.14)

  if(frameID == "APIC") {
    AttachedPictureFrame *f = new AttachedPictureFrame(data, header);
    if(d->useDefaultEncoding)
      f->setTextEncoding(d->defaultEncoding);
    return f;
  }

  // Relative Volume Adjustment (frames 4.11)

  if(frameID == "RVA2")
    return new RelativeVolumeFrame(data, header);

  // Unique File Identifier (frames 4.1)

  if(frameID == "UFID")
    return new UniqueFileIdentifierFrame(data, header);

  // General Encapsulated Object (frames 4.15)

  if(frameID == "GEOB")
    return new GeneralEncapsulatedObjectFrame(data, header);

//.........这里部分代码省略.........

/*!
 * \copydoc MetaIO::read()
 */
MusicMetadata *MetaIOID3::read(const QString &filename)
{
    if (!OpenFile(filename))
        return nullptr;

    TagLib::ID3v2::Tag *tag = GetID3v2Tag(true); // Create tag if none are found

    // if there is no ID3v2 tag, try to read the ID3v1 tag and copy it to
    // the ID3v2 tag structure
    if (tag->isEmpty())
    {
        TagLib::ID3v1::Tag *tag_v1 = GetID3v1Tag();

        if (!tag_v1)
            return nullptr;

        if (!tag_v1->isEmpty())
        {
            tag->setTitle(tag_v1->title());
            tag->setArtist(tag_v1->artist());
            tag->setAlbum(tag_v1->album());
            tag->setTrack(tag_v1->track());
            tag->setYear(tag_v1->year());
            tag->setGenre(tag_v1->genre());
        }
    }

    MusicMetadata *metadata = new MusicMetadata(filename);

    ReadGenericMetadata(tag, metadata);

    bool compilation = false;

    // Compilation Artist (TPE4 Remix) or fallback to (TPE2 Band)
    // N.B. The existance of a either frame is NOT an indication that this
    // is a compilation, but if it is then one of them will probably hold
    // the compilation artist.
    TextIdentificationFrame *tpeframe = nullptr;
    TagLib::ID3v2::FrameList tpelist = tag->frameListMap()["TPE4"];
    if (tpelist.isEmpty() || tpelist.front()->toString().isEmpty())
        tpelist = tag->frameListMap()["TPE2"];
    if (!tpelist.isEmpty())
        tpeframe = (TextIdentificationFrame *)tpelist.front();

    if (tpeframe && !tpeframe->toString().isEmpty())
    {
        QString compilation_artist = TStringToQString(tpeframe->toString())
                                                                    .trimmed();
        metadata->setCompilationArtist(compilation_artist);
    }

    // Rating and playcount, stored in POPM frame
    PopularimeterFrame *popm = findPOPM(tag, ""); // Global (all apps) tag

    // If no 'global' tag exists, look for the MythTV specific one
    if (!popm)
    {
        popm = findPOPM(tag, email);
    }

    // Fallback to using any POPM tag we can find
    if (!popm)
    {
        if (!tag->frameListMap()["POPM"].isEmpty())
            popm = dynamic_cast<PopularimeterFrame *>
                                        (tag->frameListMap()["POPM"].front());
    }

    if (popm)
    {
        int rating = popm->rating();
        rating = lroundf(static_cast<float>(rating) / 255.0f * 10.0f);
        metadata->setRating(rating);
        metadata->setPlaycount(popm->counter());
    }

    // Look for MusicBrainz Album+Artist ID in TXXX Frame
    UserTextIdentificationFrame *musicbrainz = find(tag,
                                            "MusicBrainz Album Artist Id");

    if (musicbrainz)
    {
        // If the MusicBrainz ID is the special "Various Artists" ID
        // then compilation is TRUE
        if (!compilation && !musicbrainz->fieldList().isEmpty())
        {
            TagLib::StringList l = musicbrainz->fieldList();
            for (TagLib::StringList::ConstIterator it = l.begin(); it != l.end(); it++)
            {
                QString ID = TStringToQString((*it));

                if (ID == MYTH_MUSICBRAINZ_ALBUMARTIST_UUID)
                {
                    compilation = true;
                    break;
                }
            }
//.........这里部分代码省略.........

/*!
 * \copydoc MetaIO::read()
 */
Metadata *MetaIOID3::read(QString filename)
{
    TagLib::MPEG::File *mpegfile = OpenFile(filename);

    if (!mpegfile)
        return NULL;

    TagLib::ID3v2::Tag *tag = mpegfile->ID3v2Tag();

    if (!tag)
    {
        delete mpegfile;
        return NULL;
    }

    // if there is no ID3v2 tag, try to read the ID3v1 tag and copy it to the ID3v2 tag structure
    if (tag->isEmpty())
    {
        TagLib::ID3v1::Tag *tag_v1 = mpegfile->ID3v1Tag();

        if (!tag_v1)
        {
            delete mpegfile;
            return NULL;
        }

        if (!tag_v1->isEmpty())
        {
            tag->setTitle(tag_v1->title());
            tag->setArtist(tag_v1->artist());
            tag->setAlbum(tag_v1->album());
            tag->setTrack(tag_v1->track());
            tag->setYear(tag_v1->year());
            tag->setGenre(tag_v1->genre());
        }
    }

    Metadata *metadata = new Metadata(filename);

    ReadGenericMetadata(tag, metadata);

    bool compilation = false;

    // Compilation Artist (TPE4 Remix) or fallback to (TPE2 Band)
    // N.B. The existance of a either frame is NOT an indication that this
    // is a compilation, but if it is then one of them will probably hold
    // the compilation artist.
    TextIdentificationFrame *tpeframe = NULL;
    TagLib::ID3v2::FrameList tpelist = tag->frameListMap()["TPE4"];
    if (tpelist.isEmpty() || tpelist.front()->toString().isEmpty())
        tpelist = tag->frameListMap()["TPE2"];
    if (!tpelist.isEmpty())
        tpeframe = (TextIdentificationFrame *)tpelist.front();

    if (tpeframe && !tpeframe->toString().isEmpty())
    {
        QString compilation_artist = TStringToQString(tpeframe->toString())
                                                                    .trimmed();
        metadata->setCompilationArtist(compilation_artist);
    }

    // MythTV rating and playcount, stored in POPM frame
    PopularimeterFrame *popm = findPOPM(tag, email);

    if (!popm)
    {
        if (!tag->frameListMap()["POPM"].isEmpty())
            popm = dynamic_cast<PopularimeterFrame *>
                                        (tag->frameListMap()["POPM"].front());
    }

    if (popm)
    {
        int rating = popm->rating();
        rating = static_cast<int>(((static_cast<float>(rating)/255.0)
                                                                * 10.0) + 0.5);
        metadata->setRating(rating);
        metadata->setPlaycount(popm->counter());
    }

    // Look for MusicBrainz Album+Artist ID in TXXX Frame
    UserTextIdentificationFrame *musicbrainz = find(tag,
                                            "MusicBrainz Album Artist Id");

    if (musicbrainz)
    {
        // If the MusicBrainz ID is the special "Various Artists" ID
        // then compilation is TRUE
        if (!compilation && !musicbrainz->fieldList().isEmpty())
            compilation = (MYTH_MUSICBRAINZ_ALBUMARTIST_UUID
            == TStringToQString(musicbrainz->fieldList().front()));
    }

    // TLEN - Ignored intentionally, some encoders write bad values
    // e.g. Lame under certain circumstances will always write a length of
    // 27 hours

//.........这里部分代码省略.........

/*!
 * \copydoc MetaIO::read()
 */
Metadata *MetaIOID3::read(const QString &filename)
{
    if (!OpenFile(filename))
        return NULL;

    TagLib::ID3v2::Tag *tag = GetID3v2Tag(true); // Create tag if none are found

    // if there is no ID3v2 tag, try to read the ID3v1 tag and copy it to
    // the ID3v2 tag structure
    if (tag->isEmpty())
    {
        TagLib::ID3v1::Tag *tag_v1 = GetID3v1Tag();

        if (!tag_v1)
            return NULL;

        if (!tag_v1->isEmpty())
        {
            tag->setTitle(tag_v1->title());
            tag->setArtist(tag_v1->artist());
            tag->setAlbum(tag_v1->album());
            tag->setTrack(tag_v1->track());
            tag->setYear(tag_v1->year());
            tag->setGenre(tag_v1->genre());
        }
    }

    Metadata *metadata = new Metadata(filename);

    ReadGenericMetadata(tag, metadata);

    bool compilation = false;

    // Compilation Artist (TPE4 Remix) or fallback to (TPE2 Band)
    // N.B. The existance of a either frame is NOT an indication that this
    // is a compilation, but if it is then one of them will probably hold
    // the compilation artist.
    TextIdentificationFrame *tpeframe = NULL;
    TagLib::ID3v2::FrameList tpelist = tag->frameListMap()["TPE4"];
    if (tpelist.isEmpty() || tpelist.front()->toString().isEmpty())
        tpelist = tag->frameListMap()["TPE2"];
    if (!tpelist.isEmpty())
        tpeframe = (TextIdentificationFrame *)tpelist.front();

    if (tpeframe && !tpeframe->toString().isEmpty())
    {
        QString compilation_artist = TStringToQString(tpeframe->toString())
                                                                    .trimmed();
        metadata->setCompilationArtist(compilation_artist);
    }

    // MythTV rating and playcount, stored in POPM frame
    PopularimeterFrame *popm = findPOPM(tag, email);

    if (!popm)
    {
        if (!tag->frameListMap()["POPM"].isEmpty())
            popm = dynamic_cast<PopularimeterFrame *>
                                        (tag->frameListMap()["POPM"].front());
    }

    if (popm)
    {
        int rating = popm->rating();
        rating = static_cast<int>(((static_cast<float>(rating)/255.0)
                                                                * 10.0) + 0.5);
        metadata->setRating(rating);
        metadata->setPlaycount(popm->counter());
    }

    // Look for MusicBrainz Album+Artist ID in TXXX Frame
    UserTextIdentificationFrame *musicbrainz = find(tag,
                                            "MusicBrainz Album Artist Id");

    if (musicbrainz)
    {
        // If the MusicBrainz ID is the special "Various Artists" ID
        // then compilation is TRUE
        if (!compilation && !musicbrainz->fieldList().isEmpty())
            compilation = (MYTH_MUSICBRAINZ_ALBUMARTIST_UUID
            == TStringToQString(musicbrainz->fieldList().front()));
    }

    // TLEN - Ignored intentionally, some encoders write bad values
    // e.g. Lame under certain circumstances will always write a length of
    // 27 hours

    // Length
    if (!tag->frameListMap()["TLEN"].isEmpty())
    {
        int length = tag->frameListMap()["TLEN"].front()->toString().toInt();
        LOG(VB_FILE, LOG_DEBUG,
            QString("MetaIOID3::read: Length for '%1' from tag is '%2'\n").arg(filename).arg(length));
    }

    metadata->setCompilation(compilation);

//.........这里部分代码省略.........

String ID3v2::Tag::genre() const
{
  // TODO: In the next major version (TagLib 2.0) a list of multiple genres
  // should be separated by " / " instead of " ".  For the moment to keep
  // the behavior the same as released versions it is being left with " ".

  if(!d->frameListMap["TCON"].isEmpty() &&
     dynamic_cast<TextIdentificationFrame *>(d->frameListMap["TCON"].front()))
  {
    Frame *frame = d->frameListMap["TCON"].front();

    // ID3v2.4 lists genres as the fields in its frames field list.  If the field
    // is simply a number it can be assumed that it is an ID3v1 genre number.
    // Here was assume that if an ID3v1 string is present that it should be
    // appended to the genre string.  Multiple fields will be appended as the
    // string is built.

    if(d->header.majorVersion() == 4) {
      TextIdentificationFrame *f = static_cast<TextIdentificationFrame *>(frame);
      StringList fields = f->fieldList();

      String genreString;
      bool hasNumber = false;

      for(StringList::ConstIterator it = fields.begin(); it != fields.end(); ++it) {
        bool isNumber = true;
        for(String::ConstIterator charIt = (*it).begin();
            isNumber && charIt != (*it).end();
            ++charIt)
        {
          isNumber = *charIt >= '0' && *charIt <= '9';
        }

        if(!genreString.isEmpty())
          genreString.append(' ');

        if(isNumber) {
          int number = (*it).toInt();
          if(number >= 0 && number <= 255) {
            hasNumber = true;
            genreString.append(ID3v1::genre(number));
          }
        }
        else
          genreString.append(*it);
      }
      if(hasNumber)
        return genreString;
    }

    String s = frame->toString();

    // ID3v2.3 "content type" can contain a ID3v1 genre number in parenthesis at
    // the beginning of the field.  If this is all that the field contains, do a
    // translation from that number to the name and return that.  If there is a
    // string folloing the ID3v1 genre number, that is considered to be
    // authoritative and we return that instead.  Or finally, the field may
    // simply be free text, in which case we just return the value.

    int closing = s.find(")");
    if(s.substr(0, 1) == "(" && closing > 0) {
      if(closing == int(s.size() - 1))
        return ID3v1::genre(s.substr(1, s.size() - 2).toInt());
      else
        return s.substr(closing + 1);
    }
    return s;
  }
  return String::null;
}