Skip to content

Improve feature_flag write macro #64

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
hahnjo merged 3 commits into from
Apr 21, 2026
Merged

Improve feature_flag write macro #64

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
10e8028
feature_flag: Run clang-format write.C macro
hahnjo Mar 30, 2026
fc6e531
feature_flag: Disable compression in write.C
hahnjo Mar 30, 2026
516ab96
feature_flag: Call RNTupleDescriptorBuilder::MoveDescriptor
hahnjo Mar 30, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
28 changes: 18 additions & 10 deletions structure/feature_flag/write.C
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,30 +17,38 @@ using ROOT::Experimental::Internal::RNTupleFileWriter;
using ROOT::Experimental::Internal::RNTupleSerializer;

void write(std::string_view filename = "structure.feature_flag.root") {
// Note that we are writing a file with a so-far unused feature flag. This cannot use the regular
// production API but we have to use the internal, low-level classes to create the file.
// Note that we are writing a file with a so-far unused feature flag. This
// cannot use the regular production API but we have to use the internal,
// low-level classes to create the file.

RNTupleDescriptorBuilder descBuilder;
// The following line will be required as of ROOT v6.36
// descBuilder.SetVersionForWriting();
descBuilder.SetNTuple("ntpl", "");
descBuilder.SetFeature(RNTupleDescriptor::kFeatureFlagTest);
descBuilder.AddField(RFieldDescriptorBuilder::FromField(RFieldZero()).FieldId(0).MakeDescriptor().Unwrap());
descBuilder.AddField(RFieldDescriptorBuilder::FromField(RFieldZero())
.FieldId(0)
.MakeDescriptor()
.Unwrap());
auto descriptor = descBuilder.MoveDescriptor();

RNTupleWriteOptions options;
auto writer =
RNTupleFileWriter::Recreate("ntpl", filename, RNTupleFileWriter::EContainerFormat::kTFile, RNTupleWriteOptions());
options.SetCompression(0);
auto writer = RNTupleFileWriter::Recreate(
"ntpl", filename, RNTupleFileWriter::EContainerFormat::kTFile,
options);

RNTupleSerializer serializer;

auto ctx = serializer.SerializeHeader(nullptr, descBuilder.GetDescriptor());
auto ctx = serializer.SerializeHeader(nullptr, descriptor);
auto buffer = std::make_unique<unsigned char[]>(ctx.GetHeaderSize());
ctx = serializer.SerializeHeader(buffer.get(), descBuilder.GetDescriptor());
writer->WriteNTupleHeader(buffer.get(), ctx.GetHeaderSize(), ctx.GetHeaderSize());
ctx = serializer.SerializeHeader(buffer.get(), descriptor);
writer->WriteNTupleHeader(buffer.get(), ctx.GetHeaderSize(),
ctx.GetHeaderSize());

auto szFooter = serializer.SerializeFooter(nullptr, descBuilder.GetDescriptor(), ctx);
auto szFooter = serializer.SerializeFooter(nullptr, descriptor, ctx);
buffer = std::make_unique<unsigned char[]>(szFooter);
serializer.SerializeFooter(buffer.get(), descBuilder.GetDescriptor(), ctx);
serializer.SerializeFooter(buffer.get(), descriptor, ctx);
writer->WriteNTupleFooter(buffer.get(), szFooter, szFooter);

writer->Commit();
Expand Down
Loading