1use crate::{ComponentSection, ComponentSectionId, Encode};
2use alloc::vec::Vec;
3
4/// An encoder for the start section of WebAssembly components.
5///
6/// # Example
7///
8/// ```
9/// use wasm_encoder::{Component, ComponentStartSection};
10///
11/// let start = ComponentStartSection { function_index: 0, args: [0, 1], results: 1 };
12///
13/// let mut component = Component::new();
14/// component.section(&start);
15///
16/// let bytes = component.finish();
17/// ```
18#[derive(Clone, Debug)]
19pub struct ComponentStartSection<A> {
20 /// The index to the start function.
21 pub function_index: u32,
22 /// The arguments to pass to the start function.
23 ///
24 /// An argument is an index to a value.
25 pub args: A,
26 /// The number of expected results for the start function.
27 ///
28 /// This should match the number of results for the type of
29 /// the function referenced by `function_index`.
30 pub results: u32,
31}
32
33impl<A> Encode for ComponentStartSection<A>
34where
35 A: AsRef<[u32]>,
36{
37 fn encode(&self, sink: &mut Vec<u8>) {
38 let mut bytes: Vec = Vec::new();
39 self.function_index.encode(&mut bytes);
40 self.args.as_ref().encode(&mut bytes);
41 self.results.encode(&mut bytes);
42 bytes.encode(sink);
43 }
44}
45
46impl<A> ComponentSection for ComponentStartSection<A>
47where
48 A: AsRef<[u32]>,
49{
50 fn id(&self) -> u8 {
51 ComponentSectionId::Start.into()
52 }
53}
54