untrusted/
no_panic.rs

1/// A wrapper around a slice that exposes no functions that can panic.
2///
3/// Intentionally avoids implementing `Debug`, `Eq`, and `PartialEq` to avoid
4/// creating a side channel that would leak information about the value.
5#[derive(Clone, Copy)]
6pub struct Slice<'a> {
7    bytes: &'a [u8],
8}
9
10impl<'a> Slice<'a> {
11    #[inline]
12    pub const fn new(bytes: &'a [u8]) -> Self {
13        Self { bytes }
14    }
15
16    #[inline]
17    pub fn get(&self, i: usize) -> Option<&u8> {
18        self.bytes.get(i)
19    }
20
21    #[inline]
22    pub fn subslice(&self, r: core::ops::Range<usize>) -> Option<Self> {
23        self.bytes.get(r).map(|bytes| Self { bytes })
24    }
25
26    #[inline]
27    pub fn is_empty(&self) -> bool {
28        self.bytes.is_empty()
29    }
30
31    #[inline]
32    pub fn len(&self) -> usize {
33        self.bytes.len()
34    }
35
36    #[inline]
37    pub fn as_slice_less_safe(&self) -> &'a [u8] {
38        self.bytes
39    }
40}
untrusted/no_panic.rs

untrusted/
no_panic.rs
