1//! Helpers for the generated code
2
3use super::x11_utils::TryParse;
4use core::marker::PhantomData;
5
6/// Iterator implementation used by [GetPropertyReply].
7///
8/// This is the actual type returned by [GetPropertyReply::value8], [GetPropertyReply::value16],
9/// and [GetPropertyReply::value32]. This type needs to be public due to Rust's visibility rules.
10///
11/// [GetPropertyReply]: crate::protocol::xproto::GetPropertyReply
12/// [GetPropertyReply::value8]: crate::protocol::xproto::GetPropertyReply::value8
13/// [GetPropertyReply::value16]: crate::protocol::xproto::GetPropertyReply::value16
14/// [GetPropertyReply::value32]: crate::protocol::xproto::GetPropertyReply::value32
15#[derive(Debug, Clone)]
16pub struct PropertyIterator<'a, T>(&'a [u8], PhantomData<T>);
17
18impl<'a, T> PropertyIterator<'a, T> {
19 pub(crate) fn new(value: &'a [u8]) -> Self {
20 PropertyIterator(value, PhantomData)
21 }
22}
23
24impl<T> Iterator for PropertyIterator<'_, T>
25where
26 T: TryParse,
27{
28 type Item = T;
29
30 fn next(&mut self) -> Option<Self::Item> {
31 match T::try_parse(self.0) {
32 Ok((value: T, remaining: &[u8])) => {
33 self.0 = remaining;
34 Some(value)
35 }
36 Err(_) => {
37 self.0 = &[];
38 None
39 }
40 }
41 }
42
43 fn size_hint(&self) -> (usize, Option<usize>) {
44 let size: usize = self.0.len() / core::mem::size_of::<T>();
45 (size, Some(size))
46 }
47}
48
49impl<T: TryParse> core::iter::FusedIterator for PropertyIterator<'_, T> {}
50
51#[cfg(test)]
52mod tests {
53 use super::PropertyIterator;
54 use alloc::vec::Vec;
55
56 #[test]
57 fn test_parse_u8() {
58 let input = [0u8, 1, 2, 3, 4, 5];
59 let output = PropertyIterator::new(&input).collect::<Vec<u8>>();
60 assert_eq!(&input[..], output);
61 }
62
63 #[test]
64 fn test_parse_u32() {
65 let expected = [0u32, 1, 2, 3, 4, 5];
66 let input = {
67 let mut input = Vec::new();
68 for value in &expected {
69 input.extend_from_slice(&value.to_ne_bytes());
70 }
71 input
72 };
73
74 let output = PropertyIterator::new(&input).collect::<Vec<u32>>();
75 assert_eq!(&expected[..], output);
76 }
77
78 #[test]
79 fn test_size_hint() {
80 let hint = PropertyIterator::<u32>::new(&[0; 0]).size_hint();
81 assert_eq!(hint, (0, Some(0)));
82
83 let hint = PropertyIterator::<u32>::new(&[0; 8]).size_hint();
84 assert_eq!(hint, (2, Some(2)));
85
86 // In this case, the data is not an exact multiple of the element size
87 let hint = PropertyIterator::<u32>::new(&[0; 30]).size_hint();
88 assert_eq!(hint, (7, Some(7)));
89 }
90}
91