C++ iterator::toString方法代码示例

    bool getExifDateTime(Exiv2::ExifData &exifData, QDateTime &dateTime) {
        bool anyFound = false;

        try {
            Exiv2::ExifKey key(EXIF_PHOTO_DATETIMEORIGINAL);
            Exiv2::ExifData::iterator it = exifData.findKey(key);
            if (it != exifData.end()) {
                dateTime = QDateTime::fromString(QString::fromLatin1(it->toString().c_str()), Qt::ISODate);
                anyFound = dateTime.isValid();
            }

            if (!anyFound) {
                Exiv2::ExifKey imageKey(EXIF_IMAGE_DATETIMEORIGINAL);
                Exiv2::ExifData::iterator imageIt = exifData.findKey(imageKey);
                if (imageIt != exifData.end()) {
                    dateTime = QDateTime::fromString(QString::fromLatin1(imageIt->toString().c_str()), Qt::ISODate);
                    anyFound = dateTime.isValid();
                }
            }
        }
        catch (Exiv2::Error &e) {
            LOG_WARNING << "Exiv2 error:" << e.what();
            anyFound = false;
        }
        catch (...) {
            LOG_WARNING << "Exception";
            anyFound = false;
#ifdef QT_DEBUG
            throw;
#endif
        }

        return anyFound;
    }

 bool _getExiv2Value(Exiv2::ExifData& exifData, uint16_t tagID, std::string groupName, std::string & value)
 {
     Exiv2::ExifData::iterator itr = exifData.findKey(Exiv2::ExifKey(tagID, groupName));
     if (itr != exifData.end() && itr->count())
     {
         value = itr->toString();
         return true;
     }
     else
     {
         return false;
     };
 };

QDateTime KExiv2::getDigitizationDateTime(bool fallbackToCreationTime) const
{
    try
    {
        // In first, trying to get Date & time from Exif tags.

        if (!d->exifMetadata().empty())
        {
            // Try Exif date time digitized.

            Exiv2::ExifData exifData(d->exifMetadata());
            Exiv2::ExifKey key("Exif.Photo.DateTimeDigitized");
            Exiv2::ExifData::iterator it = exifData.findKey(key);

            if (it != exifData.end())
            {
                QDateTime dateTime = QDateTime::fromString(it->toString().c_str(), Qt::ISODate);

                if (dateTime.isValid())
                {
                    kDebug() << "DateTime (Exif digitalized): " << dateTime.toString().toAscii().constData();
                    return dateTime;
                }
            }
        }

        // In second, trying to get Date & time from Iptc tags.

        if (!d->iptcMetadata().empty())
        {
            // Try digitization Iptc date time entries.

            Exiv2::IptcData iptcData(d->iptcMetadata());
            Exiv2::IptcKey keyDigitizationDate("Iptc.Application2.DigitizationDate");
            Exiv2::IptcData::iterator it = iptcData.findKey(keyDigitizationDate);

            if (it != iptcData.end())
            {
                QString IptcDateDigitization(it->toString().c_str());

                Exiv2::IptcKey keyDigitizationTime("Iptc.Application2.DigitizationTime");
                Exiv2::IptcData::iterator it2 = iptcData.findKey(keyDigitizationTime);

                if (it2 != iptcData.end())
                {
                    QString IptcTimeDigitization(it2->toString().c_str());

                    QDate date = QDate::fromString(IptcDateDigitization, Qt::ISODate);
                    QTime time = QTime::fromString(IptcTimeDigitization, Qt::ISODate);
                    QDateTime dateTime = QDateTime(date, time);

                    if (dateTime.isValid())
                    {
                        kDebug() << "Date (IPTC digitalized): " << dateTime.toString().toAscii().constData();
                        return dateTime;
                    }
                }
            }
        }
    }
    catch( Exiv2::Error& e )
    {
        d->printExiv2ExceptionError("Cannot parse Exif digitization date & time tag using Exiv2 ", e);
    }
    catch(...)
    {
        kError() << "Default exception from Exiv2";
    }

    if (fallbackToCreationTime)
        return getImageDateTime();
    else
        return QDateTime();
}

// *****************************************************************************
// Main
int main()
try {
    // Container for all metadata
    Exiv2::ExifData exifData;

    // *************************************************************************
    // Add to the Exif data

    // Create a ASCII string value (note the use of create)
    Exiv2::Value* v = Exiv2::Value::create(Exiv2::asciiString);
    // Set the value to a string
    v->read("1999:12:31 23:59:59");
    // Add the value together with its key to the Exif data container
    Exiv2::ExifKey key("Exif.Photo.DateTimeOriginal");
    exifData.add(key, v);

    std::cout << "Added key \"" << key << "\", value \"" << *v << "\"\n";
    // Delete the memory allocated by Value::create
    delete v;

    // Now create a more interesting value (without using the create method)
    Exiv2::URationalValue* rv = new Exiv2::URationalValue;
    // Set two rational components from a string
    rv->read("1/2 1/3");
    // Add more elements through the extended interface of rational value 
    rv->value_.push_back(std::make_pair(2,3));
    rv->value_.push_back(std::make_pair(3,4));
    // Add the key and value pair to the Exif data
    key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
    exifData.add(key, rv);

    std::cout << "Added key \"" << key << "\", value \"" << *rv << "\"\n";
    // Delete memory allocated on the heap
    delete rv;

    // *************************************************************************
    // Modify Exif data

    // Find the timestamp metadatum by its key
    key = Exiv2::ExifKey("Exif.Photo.DateTimeOriginal");
    Exiv2::ExifData::iterator pos = exifData.findKey(key);
    if (pos == exifData.end()) throw Exiv2::Error("Key not found");
    // Modify the value
    std::string date = pos->toString();
    date.replace(0,4,"2000");
    pos->setValue(date); 
    std::cout << "Modified key \"" << key 
              << "\", new value \"" << pos->value() << "\"\n";

    // Find the other key
    key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
    pos = exifData.findKey(key);
    if (pos == exifData.end()) throw Exiv2::Error("Key not found");
    // Get a pointer to a copy of the value
    v = pos->getValue();
    // Downcast the Value pointer to its actual type
    rv = dynamic_cast<Exiv2::URationalValue*>(v);
    if (rv == 0) throw Exiv2::Error("Downcast failed");
    // Modify the value directly through the interface of URationalValue
    rv->value_[2] = std::make_pair(88,77);
    // Copy the modified value back to the metadatum
    pos->setValue(rv);
    // Delete the memory allocated by getValue
    delete v;
    std::cout << "Modified key \"" << key 
              << "\", new value \"" << pos->value() << "\"\n";

    // *************************************************************************
    // Delete metadata from the Exif data container

    // Delete the metadatum at iterator position pos
    key = Exiv2::ExifKey("Exif.Image.PrimaryChromaticities");
    pos = exifData.findKey(key);
    if (pos == exifData.end()) throw Exiv2::Error("Key not found");
    exifData.erase(pos);
    std::cout << "Deleted key \"" << key << "\"\n";

    // *************************************************************************
    // Finally, write the remaining Exif data to an image file
    int rc = exifData.write("img_2158.jpg");
    if (rc) {
        std::string error = Exiv2::ExifData::strError(rc, "img_2158.jpg");
        throw Exiv2::Error(error);
    }

    return 0;
}
catch (Exiv2::Error& e) {
    std::cout << "Caught Exiv2 exception '" << e << "'\n";
    return -1;
}

QDateTime MetaEngine::getDigitizationDateTime(bool fallbackToCreationTime) const
{
    try
    {
        // In first, trying to get Date & time from Exif tags.

        if (!d->exifMetadata().empty())
        {
            // Try Exif date time digitized.

            Exiv2::ExifData exifData(d->exifMetadata());
            Exiv2::ExifKey key("Exif.Photo.DateTimeDigitized");
            Exiv2::ExifData::iterator it = exifData.findKey(key);

            if (it != exifData.end())
            {
                QDateTime dateTime = QDateTime::fromString(QString::fromLatin1(it->toString().c_str()), Qt::ISODate);

                if (dateTime.isValid())
                {
                    qCDebug(DIGIKAM_METAENGINE_LOG) << "DateTime (Exif digitalized): " << dateTime.toString().toLatin1().constData();
                    return dateTime;
                }
            }
        }

        // In second, we trying XMP

#ifdef _XMP_SUPPORT_

        if (!d->xmpMetadata().empty())
        {
            Exiv2::XmpData xmpData(d->xmpMetadata());
            {
                Exiv2::XmpKey key("Xmp.exif.DateTimeDigitized");
                Exiv2::XmpData::iterator it = xmpData.findKey(key);

                if (it != xmpData.end())
                {
                    QDateTime dateTime = QDateTime::fromString(QString::fromLatin1(it->toString().c_str()), Qt::ISODate);

                    if (dateTime.isValid())
                    {
                        qCDebug(DIGIKAM_METAENGINE_LOG) << "DateTime (XMP-Exif digitalized): " << dateTime.toString().toLatin1().constData();
                        return dateTime;
                    }
                }
            }
            {
                Exiv2::XmpKey key("Xmp.video.DateTimeDigitized");
                Exiv2::XmpData::iterator it = xmpData.findKey(key);

                if (it != xmpData.end())
                {
                    QDateTime dateTime = QDateTime::fromString(QString::fromLatin1(it->toString().c_str()), Qt::ISODate);

                    if (dateTime.isValid())
                    {
                        qCDebug(DIGIKAM_METAENGINE_LOG) << "DateTime (XMP-Video digitalized): " << dateTime.toString().toLatin1().constData();
                        return dateTime;
                    }
                }
            }
        }

#endif // _XMP_SUPPORT_

        // In third, trying to get Date & time from Iptc tags.

        if (!d->iptcMetadata().empty())
        {
            // Try digitization Iptc date time entries.

            Exiv2::IptcData iptcData(d->iptcMetadata());
            Exiv2::IptcKey keyDigitizationDate("Iptc.Application2.DigitizationDate");
            Exiv2::IptcData::iterator it = iptcData.findKey(keyDigitizationDate);

            if (it != iptcData.end())
            {
                QString IptcDateDigitization(QString::fromLatin1(it->toString().c_str()));

                Exiv2::IptcKey keyDigitizationTime("Iptc.Application2.DigitizationTime");
                Exiv2::IptcData::iterator it2 = iptcData.findKey(keyDigitizationTime);

                if (it2 != iptcData.end())
                {
                    QString IptcTimeDigitization(QString::fromLatin1(it2->toString().c_str()));

                    QDate date = QDate::fromString(IptcDateDigitization, Qt::ISODate);
                    QTime time = QTime::fromString(IptcTimeDigitization, Qt::ISODate);
                    QDateTime dateTime = QDateTime(date, time);

                    if (dateTime.isValid())
                    {
                        qCDebug(DIGIKAM_METAENGINE_LOG) << "Date (IPTC digitalized): " << dateTime.toString().toLatin1().constData();
                        return dateTime;
                    }
                }
            }
        }
//.........这里部分代码省略.........