binary_layout/fields/
char.rs1use crate::LayoutAs;
2use core::convert::Infallible;
3
4#[derive(Debug)]
6pub struct InvalidCharError(pub(crate) ());
7
8impl core::fmt::Display for InvalidCharError {
9 fn fmt(&self, fmt: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
10 write!(fmt, "InvalidCharError")
11 }
12}
13
14#[cfg(feature = "std")]
15impl std::error::Error for InvalidCharError {}
16
17impl LayoutAs<u32> for char {
18 type ReadError = InvalidCharError;
19 type WriteError = Infallible;
20
21 fn try_read(v: u32) -> Result<Self, Self::ReadError> {
22 char::from_u32(v).ok_or(InvalidCharError(()))
23 }
24
25 fn try_write(v: Self) -> Result<u32, Self::WriteError> {
26 Ok(u32::from(v))
27 }
28}
29
30#[cfg(test)]
31mod tests {
32 use super::*;
33 use crate::{binary_layout, InfallibleResultExt, WrappedFieldError};
34
35 const INVALID_UNICODE: u32 = 0xD83Du32;
36
37 macro_rules! test_char {
38 ($endian:ident, $endian_type:ty, $from_endian_fn:ident, $to_endian_fn:ident) => {
39 paste::paste! {
40 #[allow(non_snake_case)]
41 #[test]
42 fn [<test_char_ $endian endian_viewapi_tryread_write>]() {
43 binary_layout!(layout, $endian_type, {
44 field1: char as u32,
45 field2: char as u32,
46 field3: char as u32,
47 field4: char as u32,
48 });
49 let mut storage = [0; 1024];
50 storage[12..16].copy_from_slice(&INVALID_UNICODE.$to_endian_fn()); let mut view = layout::View::new(&mut storage);
53
54 view.field1_mut().write('a');
55 view.field2_mut().write('我');
56 view.field3_mut().write('\0');
57
58 assert_eq!('a', view.field1().try_read().unwrap());
59 assert_eq!('我', view.field2().try_read().unwrap());
60 assert_eq!('\0', view.field3().try_read().unwrap());
61 assert!(matches!(view.field4().try_read(), Err(WrappedFieldError::LayoutAsError(InvalidCharError(_)))));
62
63 assert_eq!('a', char::try_from(u32::$from_endian_fn((&storage[0..4]).try_into().unwrap())).unwrap());
64 assert_eq!('我', char::try_from(u32::$from_endian_fn((&storage[4..8]).try_into().unwrap())).unwrap());
65 assert_eq!('\0', char::try_from(u32::$from_endian_fn((&storage[8..12]).try_into().unwrap())).unwrap());
66 assert_eq!(INVALID_UNICODE, u32::$from_endian_fn((&storage[12..16]).try_into().unwrap()));
67 }
68
69 #[allow(non_snake_case)]
70 #[test]
71 fn [<test_char_ $endian endian_viewapi_tryread_trywrite>]() {
72 binary_layout!(layout, $endian_type, {
73 field1: char as u32,
74 field2: char as u32,
75 field3: char as u32,
76 field4: char as u32,
77 });
78 let mut storage = [0; 1024];
79 storage[12..16].copy_from_slice(&INVALID_UNICODE.$to_endian_fn()); let mut view = layout::View::new(&mut storage);
82
83 view.field1_mut().try_write('a').infallible_unwrap();
84 view.field2_mut().try_write('我').infallible_unwrap();
85 view.field3_mut().try_write('\0').infallible_unwrap();
86
87 assert_eq!('a', view.field1().try_read().unwrap());
88 assert_eq!('我', view.field2().try_read().unwrap());
89 assert_eq!('\0', view.field3().try_read().unwrap());
90 assert!(matches!(view.field4().try_read(), Err(WrappedFieldError::LayoutAsError(InvalidCharError(_)))));
91
92 assert_eq!('a', char::try_from(u32::$from_endian_fn((&storage[0..4]).try_into().unwrap())).unwrap());
93 assert_eq!('我', char::try_from(u32::$from_endian_fn((&storage[4..8]).try_into().unwrap())).unwrap());
94 assert_eq!('\0', char::try_from(u32::$from_endian_fn((&storage[8..12]).try_into().unwrap())).unwrap());
95 assert_eq!(INVALID_UNICODE, u32::$from_endian_fn((&storage[12..16]).try_into().unwrap()));
96 }
97 }
98 }
99 }
100
101 test_char!(little, LittleEndian, from_le_bytes, to_le_bytes);
102 test_char!(big, BigEndian, from_be_bytes, to_be_bytes);
103 test_char!(native, NativeEndian, from_ne_bytes, to_ne_bytes);
104}