void Matroska_MetaHandler::UpdateXMP()
{
XMP_IO* fileRef = parent->ioRef;
fileRef->Seek(fileRef->Length(), kXMP_SeekFromStart);
for (auto segment : _dom->_root->getElementsById(kSegment))
{
for (auto tags : segment->getElementsById(kTags))
{
for (auto tag : tags->getElementsById(kTag))
{
for (auto simple_tag : tag->getElementsById(kSimpleTag))
{
auto tag_name = simple_tag->getElementById(kTagName);
if (tag_name->_value.StringValue == "XMP")
{
auto tag_string = simple_tag->getElementById(kTagString);
// we have found valid XMP, and if it's in the very end of file, we can truncate segment
if (tag_string->_offset + tag_string->size() == fileRef->Length())
{
segment->_size._value -= tags->size();
fileRef->Truncate(tags->_offset);
fileRef->Seek(tags->_offset, kXMP_SeekFromStart);
}
// otherwise, make old XMP tag Void and create new one from the scratch
else
{
tags->wipe(fileRef);
}
}
}
}
}
}
auto segments = _dom->_root->getElementsById(kSegment);
auto segment = segments.back();
auto tag_name = std::make_shared<ebml_element_t>(kTagName, ebml_variant_t("XMP"));
auto tag_string = std::make_shared<ebml_element_t>(kTagString, ebml_variant_t(xmpPacket));
auto tag_language = std::make_shared<ebml_element_t>(kTagLanguage, ebml_variant_t("eng"));
auto tag_default = std::make_shared<ebml_element_t>(kTagDefault, ebml_variant_t(1ULL));
auto simple_tag = std::make_shared<ebml_element_t>(kSimpleTag, ebml_element_t::vec{ tag_language, tag_default, tag_name, tag_string });
auto tag = std::make_shared<ebml_element_t>(kTag, simple_tag);
auto tags = std::make_shared<ebml_element_t>(kTags, tag);
tags->write(fileRef);
segment->_size._value += tags->size();
segment->update_header(fileRef);
}
