core/array/ascii.rs
1use crate::ascii;
2
3#[cfg(not(test))]
4impl<const N: usize> [u8; N] {
5 /// Converts this array of bytes into an array of ASCII characters,
6 /// or returns `None` if any of the characters is non-ASCII.
7 ///
8 /// # Examples
9 ///
10 /// ```
11 /// #![feature(ascii_char)]
12 ///
13 /// const HEX_DIGITS: [std::ascii::Char; 16] =
14 /// *b"0123456789abcdef".as_ascii().unwrap();
15 ///
16 /// assert_eq!(HEX_DIGITS[1].as_str(), "1");
17 /// assert_eq!(HEX_DIGITS[10].as_str(), "a");
18 /// ```
19 #[unstable(feature = "ascii_char", issue = "110998")]
20 #[must_use]
21 #[inline]
22 pub const fn as_ascii(&self) -> Option<&[ascii::Char; N]> {
23 if self.is_ascii() {
24 // SAFETY: Just checked that it's ASCII
25 Some(unsafe { self.as_ascii_unchecked() })
26 } else {
27 None
28 }
29 }
30
31 /// Converts this array of bytes into an array of ASCII characters,
32 /// without checking whether they're valid.
33 ///
34 /// # Safety
35 ///
36 /// Every byte in the array must be in `0..=127`, or else this is UB.
37 #[unstable(feature = "ascii_char", issue = "110998")]
38 #[must_use]
39 #[inline]
40 pub const unsafe fn as_ascii_unchecked(&self) -> &[ascii::Char; N] {
41 let byte_ptr: *const [u8; N] = self;
42 let ascii_ptr = byte_ptr as *const [ascii::Char; N];
43 // SAFETY: The caller promised all the bytes are ASCII
44 unsafe { &*ascii_ptr }
45 }
46}