EbmlElement *
kax_file_c::read_one_element() {
if (m_segment_end && (m_in.getFilePointer() >= m_segment_end))
return nullptr;
auto upper_lvl_el = 0;
auto l1 = m_es->FindNextElement(EBML_CLASS_CONTEXT(KaxSegment), upper_lvl_el, 0xFFFFFFFFL, true);
if (!l1)
return nullptr;
auto callbacks = find_ebml_callbacks(EBML_INFO(KaxSegment), EbmlId(*l1));
if (!callbacks)
callbacks = &EBML_CLASS_CALLBACK(KaxSegment);
auto l2 = static_cast<EbmlElement *>(nullptr);
try {
l1->Read(*m_es.get(), EBML_INFO_CONTEXT(*callbacks), upper_lvl_el, l2, true);
} catch (std::runtime_error &e) {
mxdebug_if(m_debug_resync, boost::format("exception reading element data: %1%\n") % e.what());
m_in.setFilePointer(l1->GetElementPosition() + 1);
delete l1;
return nullptr;
}
auto element_size = get_element_size(l1);
if (m_debug_resync)
mxinfo(boost::format("kax_file::read_one_element(): read element at %1% calculated size %2% stored size %3%\n")
% l1->GetElementPosition() % element_size % (l1->IsFiniteSize() ? (boost::format("%1%") % l1->ElementSize()).str() : std::string("unknown")));
m_in.setFilePointer(l1->GetElementPosition() + element_size, seek_beginning);
return l1;
}
std::map<id_timecode_t, uint64_t>
cues_c::calculate_block_positions(KaxCluster &cluster)
const {
std::map<id_timecode_t, uint64_t> positions;
for (auto child : cluster) {
auto simple_block = dynamic_cast<KaxSimpleBlock *>(child);
if (simple_block) {
simple_block->SetParent(cluster);
positions[ id_timecode_t{ simple_block->TrackNum(), simple_block->GlobalTimecode() } ] = simple_block->GetElementPosition();
continue;
}
auto block_group = dynamic_cast<KaxBlockGroup *>(child);
if (!block_group)
continue;
auto block = FindChild<KaxBlock>(block_group);
if (!block)
continue;
block->SetParent(cluster);
positions[ id_timecode_t{ block->TrackNum(), block->GlobalTimecode() } ] = block->GetElementPosition();
}
return positions;
}
uint64 EbmlVoid::ReplaceWith(EbmlElement & EltToReplaceWith, IOCallback & output, bool ComeBackAfterward, bool bWithDefault)
{
EltToReplaceWith.UpdateSize(bWithDefault);
if (HeadSize() + GetSize() < EltToReplaceWith.GetSize() + EltToReplaceWith.HeadSize()) {
// the element can't be written here !
return INVALID_FILEPOS_T;
}
if (HeadSize() + GetSize() - EltToReplaceWith.GetSize() - EltToReplaceWith.HeadSize() == 1) {
// there is not enough space to put a filling element
return INVALID_FILEPOS_T;
}
uint64 CurrentPosition = output.getFilePointer();
output.setFilePointer(GetElementPosition());
EltToReplaceWith.Render(output, bWithDefault);
if (HeadSize() + GetSize() - EltToReplaceWith.GetSize() - EltToReplaceWith.HeadSize() > 1) {
// fill the rest with another void element
EbmlVoid aTmp;
aTmp.SetSize_(HeadSize() + GetSize() - EltToReplaceWith.GetSize() - EltToReplaceWith.HeadSize() - 1); // 1 is the length of the Void ID
int HeadBefore = aTmp.HeadSize();
aTmp.SetSize_(aTmp.GetSize() - CodedSizeLength(aTmp.GetSize(), aTmp.GetSizeLength(), aTmp.IsFiniteSize()));
int HeadAfter = aTmp.HeadSize();
if (HeadBefore != HeadAfter) {
aTmp.SetSizeLength(CodedSizeLength(aTmp.GetSize(), aTmp.GetSizeLength(), aTmp.IsFiniteSize()) - (HeadAfter - HeadBefore));
}
aTmp.RenderHead(output, false, bWithDefault); // the rest of the data is not rewritten
}
if (ComeBackAfterward) {
output.setFilePointer(CurrentPosition);
}
return GetSize() + HeadSize();
}
uint64 KaxSegment::GetGlobalPosition(uint64 aRelativePosition) const
{
return aRelativePosition + GetElementPosition() + HeadSize();
}
uint64 KaxSegment::GetRelativePosition(uint64 aGlobalPosition) const
{
return aGlobalPosition - GetElementPosition() - HeadSize();
}
EbmlElement *
kax_file_c::read_next_level1_element_internal(uint32_t wanted_id) {
if (m_segment_end && (m_in.getFilePointer() >= m_segment_end))
return nullptr;
m_resynced = false;
m_resync_start_pos = 0;
// Read the next ID.
auto search_start_pos = m_in.getFilePointer();
auto actual_id = vint_c::read_ebml_id(m_in);
m_in.setFilePointer(search_start_pos, seek_beginning);
if (m_debug_read_next)
mxinfo(boost::format("kax_file::read_next_level1_element(): search at %1% for %|4$x| act id %|2$x| is_valid %3%\n") % search_start_pos % actual_id.m_value % actual_id.is_valid() % wanted_id);
// If no valid ID was read then re-sync right away. No other tests
// can be run.
if (!actual_id.is_valid())
return resync_to_level1_element(wanted_id);
// Easiest case: next level 1 element following the previous one
// without any element inbetween.
if ( (wanted_id == actual_id.m_value)
|| ( (0 == wanted_id)
&& ( is_level1_element_id(actual_id)
|| is_global_element_id(actual_id)))) {
auto l1 = read_one_element();
if (l1)
return l1;
}
// If a specific level 1 is wanted then look for next ID by skipping
// other level 1 or special elements. If that files fallback to a
// byte-for-byte search for the ID.
if ((0 != wanted_id) && (is_level1_element_id(actual_id) || is_global_element_id(actual_id))) {
m_in.setFilePointer(search_start_pos, seek_beginning);
auto l1 = read_one_element();
if (l1) {
auto element_size = get_element_size(l1);
auto ok = (0 != element_size) && m_in.setFilePointer2(l1->GetElementPosition() + element_size, seek_beginning);
if (m_debug_read_next)
mxinfo(boost::format("kax_file::read_next_level1_element(): other level 1 element %1% new pos %2% fsize %3% epos %4% esize %5%\n")
% EBML_NAME(l1) % (l1->GetElementPosition() + element_size) % m_file_size
% l1->GetElementPosition() % element_size);
delete l1;
return ok ? read_next_level1_element(wanted_id) : nullptr;
}
}
// Last case: no valid ID found. Try a byte-for-byte search for the
// next wanted/level 1 ID. Also try to locate at least three valid
// ID/sizes, not just one ID.
m_in.setFilePointer(search_start_pos, seek_beginning);
return resync_to_level1_element(wanted_id);
}
