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use std::borrow::Cow;
use crate::{encoding_size, Encode, Section, SectionId};
/// A custom section holding arbitrary data.
#[derive(Clone, Debug)]
pub struct CustomSection<'a> {
/// The name of this custom section.
pub name: Cow<'a, str>,
/// This custom section's data.
pub data: Cow<'a, [u8]>,
}
impl Encode for CustomSection<'_> {
fn encode(&self, sink: &mut Vec<u8>) {
let encoded_name_len = encoding_size(u32::try_from(self.name.len()).unwrap());
(encoded_name_len + self.name.len() + self.data.len()).encode(sink);
self.name.encode(sink);
sink.extend(&*self.data);
}
}
impl Section for CustomSection<'_> {
fn id(&self) -> u8 {
SectionId::Custom.into()
}
}
/// A raw custom section where the bytes specified contain the leb-encoded
/// length of the custom section, the custom section's name, and the custom
/// section's data.
#[derive(Clone, Debug)]
pub struct RawCustomSection<'a>(pub &'a [u8]);
impl Encode for RawCustomSection<'_> {
fn encode(&self, sink: &mut Vec<u8>) {
sink.extend(self.0);
}
}
impl Section for RawCustomSection<'_> {
fn id(&self) -> u8 {
SectionId::Custom.into()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_custom_section() {
let custom = CustomSection {
name: "test".into(),
data: Cow::Borrowed(&[11, 22, 33, 44]),
};
let mut encoded = vec![];
custom.encode(&mut encoded);
#[rustfmt::skip]
assert_eq!(encoded, vec![
// LEB128 length of section.
9,
// LEB128 length of name.
4,
// Name.
b't', b'e', b's', b't',
// Data.
11, 22, 33, 44,
]);
}
}