1#![deny(clippy::pedantic)]
2
3pub use flat_bytes_derive::flat_enum;
4pub use flat_bytes_derive::Flat;
5
6pub trait Flat: Sized {
7 fn serialize(&self) -> Vec<u8>;
8 fn deserialize_with_size(data: &[u8]) -> Option<(Self, usize)>;
9 #[must_use]
10 fn deserialize(data: &[u8]) -> Option<Self> {
11 Self::deserialize_with_size(data).map(|(r, _)| r)
12 }
13}
14
15macro_rules! impl_primitive {
16 ($t:ident) => {
17 impl Flat for $t {
18 fn serialize(&self) -> Vec<u8> {
19 self.to_le_bytes().to_vec()
20 }
21
22 fn deserialize_with_size(data: &[u8]) -> Option<(Self, usize)> {
23 if data.len() < std::mem::size_of::<Self>() {
24 return None;
25 }
26 let mut tmp = [0u8; std::mem::size_of::<Self>()];
27 tmp.copy_from_slice(&data[..::std::mem::size_of::<Self>()]);
28 Some((Self::from_le_bytes(tmp), ::std::mem::size_of::<Self>()))
29 }
30 }
31 };
32}
33
34impl_primitive!(u8);
35impl_primitive!(u16);
36impl_primitive!(u32);
37impl_primitive!(u64);
38impl_primitive!(i8);
39impl_primitive!(i16);
40impl_primitive!(i32);
41impl_primitive!(i64);
42
43impl Flat for bool {
44 fn serialize(&self) -> Vec<u8> {
45 Flat::serialize(&(u8::from(*self)))
46 }
47
48 fn deserialize_with_size(data: &[u8]) -> Option<(Self, usize)> {
49 <u8 as Flat>::deserialize_with_size(data).map(|(v, s)| (v != 0, s))
50 }
51}
52
53macro_rules! impl_array {
54 (@step ($d: ident, $idx:expr,) -> ($($body:tt)*)) => {
55 impl_array!(@as_expr [$($body)*])
56 };
57 (@step ($d: ident, $idx:expr, $t:ident, $($ts:ident,)*) -> ($($body:tt)*)) => {
58 impl_array!(@step ($d, $idx+1, $($ts,)*) -> ($($body)* $t::deserialize(&$d[::std::mem::size_of::<$t>()*($idx)..])?,))
59 };
60 (@as_expr $e:expr) => {$e};
61 {$n:expr, $t:ident $($ts:ident)*}=> {
62 impl<T: Flat> Flat for [T; $n] {
63 fn serialize(&self) -> Vec<u8> {
64 self.iter().map(Flat::serialize).flatten().collect()
65 }
66
67 fn deserialize_with_size(data: &[u8]) -> Option<(Self, usize)> {
68 let res =
69 impl_array!(@step (data, 0, $t, $($ts,)*) -> ());
70 Some((res, ::std::mem::size_of::<Self>()))
71 }
72 }
73 impl_array!{($n - 1), $($ts)*}
74 };
75 {$n:expr,} => {
76 impl<T: Flat> Flat for [T; $n] {
77 fn serialize(&self) -> Vec<u8> {
78 vec![]
79 }
80
81 fn deserialize_with_size(_data: &[u8]) -> Option<(Self, usize)> {
82 Some(([], 0))
83 }
84 }
85 };
86}
87impl_array! {32, T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T}
88
89#[cfg(test)]
90mod tests {
91 use super::*;
92 use crate as flat_bytes;
93
94 flat_enum! {
95 #[repr(u8)]
96 pub enum Foo {
97 Bar = 1,
98 Baz(bool) = 3,
99 Blubb{a: bool, b: u8},
100 }
101 }
102
103 static FOO: [u16; 4] = [1, 2, 3, 4];
104
105 #[derive(Flat)]
106 struct Header {
107 magic: [u8; 2],
108 size: u16,
109 admin: bool,
110 }
111
112 #[derive(Flat)]
113 struct Wrapper(Foo);
114
115 #[test]
116 fn serialize() {
117 #![allow(clippy::many_single_char_names)]
118
119 let a = Foo::Bar;
120 assert_eq!(a.serialize(), vec![1]);
121 let b = Foo::Baz(true);
122 assert_eq!(b.serialize(), vec![3, 1]);
123 let b = Foo::Baz(false);
124 assert_eq!(b.serialize(), vec![3, 0]);
125 let c = Foo::Blubb { a: true, b: 1 };
126 assert_eq!(c.serialize(), vec![4, 1, 1]);
127 let c = Foo::Blubb { a: false, b: 2 };
128 assert_eq!(c.serialize(), vec![4, 0, 2]);
129
130 assert_eq!(FOO.serialize(), vec![1, 0, 2, 0, 3, 0, 4, 0]);
131
132 let h = Header {
133 magic: *b"AB",
134 size: 123,
135 admin: true,
136 };
137 assert_eq!(h.serialize(), vec![0x41, 0x42, 123, 0, 1]);
138
139 let w = Wrapper(Foo::Bar);
140 assert_eq!(w.serialize(), vec![1]);
141 }
142
143 #[test]
144 fn deserialize() {
145 assert!(Foo::deserialize(&[]).is_none());
146 assert!(Foo::deserialize(&[5]).is_none());
147 assert!(Foo::deserialize(&[0]).is_none());
148 let a = Foo::deserialize(&[1]).unwrap();
149 assert!(matches!(a, Foo::Bar));
150 let b = Foo::deserialize(&[3, 0]).unwrap();
151 assert!(matches!(b, Foo::Baz(false)));
152 let b = Foo::deserialize(&[3, 1]).unwrap();
153 assert!(matches!(b, Foo::Baz(true)));
154 let c = Foo::deserialize(&[4, 1, 1]).unwrap();
155 assert!(matches!(c, Foo::Blubb { a: true, b: 1 }));
156 let c = Foo::deserialize(&[4, 0, 2]).unwrap();
157 assert!(matches!(c, Foo::Blubb { a: false, b: 2 }));
158
159 assert_eq!(
160 <[u16; 4]>::deserialize(&[1, 0, 2, 0, 3, 0, 4, 0]).unwrap(),
161 FOO
162 );
163
164 let w = Wrapper::deserialize(&[1]).unwrap();
165 assert!(matches!(w.0, Foo::Bar));
166 }
167}