C++ StringList::isEmpty方法代码示例

QString FileHelper::extractFlacFeature(const QString &featureToExtract) const
{
	QString feature;
	if (TagLib::FLAC::File *flacFile = static_cast<TagLib::FLAC::File*>(_file)) {
		if (flacFile->ID3v2Tag()) {

			QString key = this->convertKeyToID3v2Key(featureToExtract);
			TagLib::ID3v2::FrameList l = flacFile->ID3v2Tag()->frameListMap()[key.toStdString().data()];
			// Fallback to the generic map in case we didn't find the matching key
			if (l.isEmpty()) {

				TagLib::StringList list = flacFile->properties()[featureToExtract.toStdString()];
				if (!list.isEmpty()) {
					feature = list.front().toCString(true);
				}

			} else {
				feature = QString(l.front()->toString().toCString(true));
			}
		} else if (flacFile->ID3v1Tag()) {
			qDebug() << Q_FUNC_INFO << "Not yet implemented for ID3v1Tag FLAC file";
		} else if (flacFile->xiphComment()) {
			const TagLib::Ogg::FieldListMap map = flacFile->xiphComment()->fieldListMap();
			if (!map[featureToExtract.toStdString().data()].isEmpty()) {
				feature = QString(map[featureToExtract.toStdString().data()].front().toCString(true));
			}
		}
	}
	return feature;
}

/** Convert the existing rating number into a smaller range from 1 to 5. */
int FileHelper::rating() const
{
	int r = -1;

	/// TODO other types?
	switch (_fileType) {
	case EXT_MP3: {
		TagLib::MPEG::File *mpegFile = static_cast<TagLib::MPEG::File*>(_file);
		if (mpegFile && mpegFile->hasID3v2Tag()) {
			r = this->ratingForID3v2(mpegFile->ID3v2Tag());
		}
		break;
	}
	case EXT_FLAC: {
		if (TagLib::FLAC::File *flacFile = static_cast<TagLib::FLAC::File*>(_file)) {
			if (flacFile->hasID3v2Tag()) {
				r = this->ratingForID3v2(flacFile->ID3v2Tag());
			} else if (flacFile->hasID3v1Tag()) {
				qDebug() << Q_FUNC_INFO << "Not implemented (FLAC ID3v1)";
			} else if (flacFile->hasXiphComment()) {
				TagLib::StringList list = flacFile->xiphComment()->fieldListMap()["RATING"];
				if (!list.isEmpty()) {
					r = list.front().toInt();
				}
			}
		}
		break;
	}
	default:
		break;
	}
	return r;
}

QString FileHelper::extractGenericFeature(const QString &featureToExtract) const
{
	QString feature;
	TagLib::PropertyMap p = _file->properties();
	if (p.contains(featureToExtract.toStdString().data())) {
		TagLib::StringList list = p[featureToExtract.toStdString().data()];
		if (!list.isEmpty()) {
			feature = list.front().toCString(true);
		}
	}
	return feature;
}

QPixmap VorbisMetaDataModel::cover()
{
    TagLib::Ogg::Vorbis::File file(m_path.toLocal8Bit().constData());
    TagLib::Ogg::XiphComment *tag = file.tag();
    if(!tag)
        return QPixmap();
    TagLib::StringList list = tag->fieldListMap()["METADATA_BLOCK_PICTURE"];
    if(list.isEmpty())
        return QPixmap();
    for(uint i = 0; i < list.size(); ++i)
    {
        TagLib::String value = list[i];
        QByteArray block = QByteArray::fromBase64(TStringToQString_qt4(value).toAscii());
        if(block.size() < 32)
            continue;
        qint64 pos = 0;
        if(readPictureBlockField(block, pos) != 3) //picture type, use front cover only
            continue;
        pos += 4;
        int mimeLength = readPictureBlockField(block, pos); //mime type length
        pos += 4;
        pos += mimeLength; //skip mime type
        int descLength = readPictureBlockField(block, pos); //description length
        pos += 4;
        pos += descLength; //skip description
        pos += 4; //width
        pos += 4; //height
        pos += 4; //color depth
        pos += 4; //the number of colors used
        int length = readPictureBlockField(block, pos); //picture size
        pos += 4;
        QPixmap cover;
        cover.loadFromData(block.mid(pos, length)); //read binary picture data
        return cover;
    }
    return QPixmap();
}

void TagLibExtractor::extract(ExtractionResult* result)
{
    const QString fileUrl = result->inputUrl();
    const QString mimeType = result->inputMimetype();

    TagLib::FileRef file(fileUrl.toUtf8().constData(), true);
    if (file.isNull()) {
        return;
    }

    TagLib::Tag* tags = file.tag();
    result->addType(Type::Audio);

    TagLib::String artists;
    TagLib::String albumArtists;
    TagLib::String composers;
    TagLib::String lyricists;
    TagLib::StringList genres;

    // Handling multiple tags in mpeg files.
    if ((mimeType == QLatin1String("audio/mpeg")) || (mimeType == QLatin1String("audio/mpeg3")) || (mimeType == QLatin1String("audio/x-mpeg"))) {
        TagLib::MPEG::File mpegFile(fileUrl.toUtf8().constData(), true);
        if (mpegFile.ID3v2Tag() && !mpegFile.ID3v2Tag()->isEmpty()) {
            TagLib::ID3v2::FrameList lstID3v2;

            // Artist.
            lstID3v2 = mpegFile.ID3v2Tag()->frameListMap()["TPE1"];
            if (!lstID3v2.isEmpty()) {
                for (TagLib::ID3v2::FrameList::ConstIterator it = lstID3v2.begin(); it != lstID3v2.end(); ++it) {
                    if (!artists.isEmpty()) {
                        artists += ", ";
                    }
                    artists += (*it)->toString();
                }
            }

            // Album Artist.
            lstID3v2 = mpegFile.ID3v2Tag()->frameListMap()["TPE2"];
            if (!lstID3v2.isEmpty()) {
                for (TagLib::ID3v2::FrameList::ConstIterator it = lstID3v2.begin(); it != lstID3v2.end(); ++it) {
                    if (!albumArtists.isEmpty()) {
                        albumArtists += ", ";
                    }
                    albumArtists += (*it)->toString();
                }
            }

            // Composer.
            lstID3v2 = mpegFile.ID3v2Tag()->frameListMap()["TCOM"];
            if (!lstID3v2.isEmpty()) {
                for (TagLib::ID3v2::FrameList::ConstIterator it = lstID3v2.begin(); it != lstID3v2.end(); ++it) {
                    if (!composers.isEmpty()) {
                        composers += ", ";
                    }
                    composers += (*it)->toString();
                }
            }

            // Lyricist.
            lstID3v2 = mpegFile.ID3v2Tag()->frameListMap()["TEXT"];
            if (!lstID3v2.isEmpty()) {
                for (TagLib::ID3v2::FrameList::ConstIterator it = lstID3v2.begin(); it != lstID3v2.end(); ++it) {
                    if (!lyricists.isEmpty()) {
                        lyricists += ", ";
                    }
                    lyricists += (*it)->toString();
                }
            }

            // Genre.
            lstID3v2 = mpegFile.ID3v2Tag()->frameListMap()["TCON"];
            if (!lstID3v2.isEmpty()) {
                for (TagLib::ID3v2::FrameList::ConstIterator it = lstID3v2.begin(); it != lstID3v2.end(); ++it) {
                    genres.append((*it)->toString());
                }
            }

        }
    }

    // Handling multiple tags in Ogg containers.
    {
        TagLib::Ogg::FieldListMap lstOgg;

        // FLAC files.
        if (mimeType == QLatin1String("audio/flac")) {
            TagLib::FLAC::File flacFile(fileUrl.toUtf8().constData(), true);
            if (flacFile.xiphComment() && !flacFile.xiphComment()->isEmpty()) {
                lstOgg = flacFile.xiphComment()->fieldListMap();
            }
        }

        // Vorbis files.
        if (mimeType == QLatin1String("audio/ogg") || mimeType == QLatin1String("audio/x-vorbis+ogg")) {
            TagLib::Ogg::Vorbis::File oggFile(fileUrl.toUtf8().constData(), true);
            if (oggFile.tag() && !oggFile.tag()->isEmpty()) {
                lstOgg = oggFile.tag()->fieldListMap();
            }
        }

//.........这里部分代码省略.........