A zero-allocation no_std-compatible zero-cost way to convert hex-strings to byte-arrays at compile time.
To add to your Cargo.toml:
hexlit = "0.5.5"
use hexlit::hex;
fn main() {
const DATA: [u8; 4] = hex!("01020304");
assert_eq!(DATA, [1, 2, 3, 4]);
assert_eq!(hex!("0xDEADBEEF"), [0xDE, 0xAD, 0xBE, 0xEF]);
assert_eq!(hex!("a1b2c3d4"), [0xA1, 0xB2, 0xC3, 0xD4]);
assert_eq!(hex!("E5 E6 90 92"), [0xE5, 0xE6, 0x90, 0x92]);
assert_eq!(hex!("0a0B0C0d"), [10, 11, 12, 13]);
assert_eq!(hex!(1a 0_b 0C 0d), [0x1a, 11, 12, 13]);
assert_eq!(hex!(0F 03|0B|0C|0d), [15, 3, 11, 12, 13]);
assert_eq!(hex!(0A-0B-0C-0d), [10, 11, 12, 13]);
assert_eq!(
hex!(
A1 B2
C3
D4
),
[0xA1, 0xB2, 0xC3, 0xD4]
);
}