encdec_macros/
lib.rs

1//! Macros for deriving [`Decode`] and [`Encode`]
2//!
3
4extern crate proc_macro;
5use proc_macro::TokenStream;
6
7mod attrs;
8mod decode;
9mod encode;
10
11/// `#[derive(Encode)]` support.
12///
13/// generates an [`Encode`][encdec_base::encode::Encode] implementation equivalent to calling `.encode()` on each field in order.
14///
15/// for example:
16/// ```
17/// # use encdec_base::{encode::Encode, Error};
18/// #[derive(Debug, PartialEq)]
19/// struct Something {
20///     a: u8,
21///     b: u16,
22///     c: [u8; 3],
23/// }
24///
25/// // `#[derive(Decode)]` equivalent implementation
26/// impl Encode for Something {
27///   type Error = Error;
28///
29///   fn encode_len(&self) -> Result<usize, Self::Error> {
30///     Ok(1 + 2 + 3)
31///   }
32///
33///   fn encode(&self, buff: &mut [u8]) -> Result<usize, Self::Error> {
34///     let mut index = 0;
35///     buff[index] = self.a;
36///     index += 1;
37///
38///     buff[1] = self.b as u8;
39///     buff[2] = (self.b >> 8) as u8;
40///     index += 2;
41///
42///     buff[3..][..3].copy_from_slice(&self.c);
43///     index += 3;
44///     
45///     Ok(index)
46///   }
47/// }
48/// ```
49#[proc_macro_derive(Encode, attributes(encdec))]
50pub fn derive_encode_impl(input: TokenStream) -> TokenStream {
51    encode::derive_encode_impl(input)
52}
53
54/// `#[derive(Decode)]` support.
55///
56/// generates a [`Decode`][encdec_base::decode::Decode] implementation equivalent to calling `.decode()` on each field in order.
57///
58/// for example:
59/// ```
60/// # use encdec_base::{decode::Decode, Error};
61/// #[derive(Debug, PartialEq)]
62/// struct Something {
63///     a: u8,
64///     b: u16,
65///     c: [u8; 3],
66/// }
67///
68/// // `#[derive(Decode)]` equivalent implementation
69/// impl <'a> Decode<'a> for Something {
70///   type Output = Something;
71///   type Error = Error;
72///
73///   fn decode(buff: &[u8]) -> Result<(Self::Output, usize), Self::Error> {
74///     let mut index = 0;
75///
76///     let a = buff[0];
77///     index += 1;
78///
79///     let b = buff[1] as u16 | (buff[2] as u16) << 8;
80///     index += 2;
81///
82///     let mut c = [0u8; 3];
83///     c.copy_from_slice(&buff[3..][..3]);
84///     index += 3;
85///
86///     Ok((Self{a, b, c}, index))
87///   }
88/// }
89/// ```
90#[proc_macro_derive(Decode, attributes(encdec))]
91pub fn derive_decode_borrowed_impl(input: TokenStream) -> TokenStream {
92    decode::derive_decode_impl(input, false)
93}
94
95/// `#[derive(DecodeOwned)]` support.
96///
97/// generates a [`DecodeOwned`][encdec_base::decode::DecodeOwned] implementation equivalent to calling `.decode()` on each field in order.
98///
99/// for example:
100/// ```
101/// # use encdec_base::{decode::DecodeOwned, Error};
102/// #[derive(Debug, PartialEq)]
103/// struct Something {
104///     a: u8,
105///     b: u16,
106///     c: [u8; 3],
107/// }
108///
109/// // `#[derive(Decode)]` equivalent implementation
110/// impl DecodeOwned for Something {
111///   type Output = Something;
112///   type Error = Error;
113///
114///   fn decode_owned(buff: &[u8]) -> Result<(Self::Output, usize), Self::Error> {
115///     let mut index = 0;
116///
117///     let a = buff[0];
118///     index += 1;
119///
120///     let b = buff[1] as u16 | (buff[2] as u16) << 8;
121///     index += 2;
122///
123///     let mut c = [0u8; 3];
124///     c.copy_from_slice(&buff[3..][..3]);
125///     index += 3;
126///
127///     Ok((Self{a, b, c}, index))
128///   }
129/// }
130/// ```
131#[proc_macro_derive(DecodeOwned, attributes(encdec))]
132pub fn derive_decode_owned_impl(input: TokenStream) -> TokenStream {
133    decode::derive_decode_impl(input, true)
134}
encdec_macros/lib.rs

encdec_macros/
lib.rs
