use crate::extension::{tree, Tree};
impl Tree {
pub fn write_to(&self, mut out: impl std::io::Write) -> Result<(), std::io::Error> {
fn tree_entry(out: &mut impl std::io::Write, tree: &Tree) -> Result<(), std::io::Error> {
let mut buf = itoa::Buffer::new();
let num_entries = match tree.num_entries {
Some(num_entries) => buf.format(num_entries),
None => buf.format(-1),
};
out.write_all(tree.name.as_slice())?;
out.write_all(b"\0")?;
out.write_all(num_entries.as_bytes())?;
out.write_all(b" ")?;
let num_children = buf.format(tree.children.len());
out.write_all(num_children.as_bytes())?;
out.write_all(b"\n")?;
if tree.num_entries.is_some() {
out.write_all(tree.id.as_bytes())?;
}
for child in &tree.children {
tree_entry(out, child)?;
}
Ok(())
}
let signature = tree::SIGNATURE;
let estimated_size = self.num_entries.unwrap_or(0) * (300 + 3 + 1 + 3 + 1 + 20);
let mut entries: Vec<u8> = Vec::with_capacity(estimated_size as usize);
tree_entry(&mut entries, self)?;
out.write_all(&signature)?;
out.write_all(&(u32::try_from(entries.len()).expect("less than 4GB tree extension")).to_be_bytes())?;
out.write_all(&entries)?;
Ok(())
}
}