Exiv2

            uint32_t curOffset = io_->tell();

            // Write IPTC_NAA resource block

                newResLength += writeIptcData(iptcData_, outIo);

                resourceSize = (resourceSize + 1) & ~1;    // adjust for padding

                iptcDone = true;

            }

            // Write ExifInfo resource block

                newResLength += writeExifData(exifData_, outIo);

                resourceSize = (resourceSize + 1) & ~1;    // adjust for padding

                exifDone = true;

            }

            // Write XMPpacket resource block

                newResLength += writeXmpData(xmpData_, outIo);

                resourceSize = (resourceSize + 1) & ~1;    // adjust for padding

                xmpDone = true;

                us2Data(buf, resourceId, bigEndian);

                if (outIo.write(buf, 2) != 2) throw Error(21);

                // Write resource name as Pascal string

                if (outIo.write(buf, 1) != 1) throw Error(21);

                buf[0] = resourceNameFirstChar;

                if (outIo.write(buf, 1) != 1) throw Error(21);