1 // Copyright 2023 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 use proc_macro2::{Literal, TokenStream};
16 use quote::{format_ident, quote};
17
18 use crate::ast;
19
20 use super::utils::get_integer_type;
21
generate_enum(id: &str, tags: &[ast::Tag], width: usize) -> TokenStream22 pub fn generate_enum(id: &str, tags: &[ast::Tag], width: usize) -> TokenStream {
23 let id_ident = format_ident!("{id}");
24 let tag_ids = tags.iter().map(|tag| format_ident!("{}", tag.id())).collect::<Vec<_>>();
25 let tag_values = tags
26 .iter()
27 .map(|tag| Literal::u64_unsuffixed(tag.value().unwrap() as u64))
28 .collect::<Vec<_>>();
29 let backing_ident = get_integer_type(width);
30
31 quote! {
32 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
33 pub enum #id_ident {
34 #(#tag_ids),*
35 }
36
37 impl #id_ident {
38 pub fn new(value: #backing_ident) -> Result<Self, ParseError> {
39 match value {
40 #(#tag_values => Ok(Self::#tag_ids)),*,
41 _ => Err(ParseError::InvalidEnumValue),
42 }
43 }
44
45 pub fn value(&self) -> #backing_ident {
46 match self {
47 #(Self::#tag_ids => #tag_values),*,
48 }
49 }
50
51 fn try_parse(buf: BitSlice) -> Result<Self, ParseError> {
52 let value = buf.slice(#width)?.try_parse()?;
53 match value {
54 #(#tag_values => Ok(Self::#tag_ids)),*,
55 _ => Err(ParseError::InvalidEnumValue),
56 }
57 }
58 }
59
60 impl Serializable for #id_ident {
61 fn serialize(&self, writer: &mut impl BitWriter) -> Result<(), SerializeError> {
62 writer.write_bits(#width, || Ok(self.value()));
63 Ok(())
64 }
65 }
66
67 impl From<#id_ident> for #backing_ident {
68 fn from(x: #id_ident) -> #backing_ident {
69 x.value()
70 }
71 }
72
73 impl TryFrom<#backing_ident> for #id_ident {
74 type Error = ParseError;
75
76 fn try_from(value: #backing_ident) -> Result<Self, ParseError> {
77 Self::new(value)
78 }
79 }
80 }
81 }
82