pub trait BitSize {
const N_BITS: u16;
#[expect(clippy::cast_possible_truncation)]
const N_BYTES: u8 = {
let n_bytes = Self::N_BITS.div_ceil(8);
assert!(n_bytes <= u8::MAX as u16, "value type exceeds 255 bytes");
n_bytes as u8
};
const N_WORDS: u16 = Self::N_BITS.div_ceil(16);
fn assert_valid<const N_MAX_BYTES: u8>() {
const {
assert!(Self::N_BYTES >= 1, "value type must be non-empty");
assert!(Self::N_BYTES <= N_MAX_BYTES, "value is too large");
};
}
}
impl<T: BitSize, const N: usize> BitSize for &[T; N] {
#[expect(clippy::cast_possible_truncation)]
const N_BITS: u16 = match (T::N_BITS as usize).checked_mul(N) {
Some(n_bits) if n_bits <= u16::MAX as usize => n_bits as u16,
_ => panic!("array size overflow"),
};
}
impl<T: BitSize, const N: usize> BitSize for [T; N] {
const N_BITS: u16 = <&[T; N]>::N_BITS;
}
macro_rules! impl_for {
($type:ty, $n_bits:literal) => {
impl BitSize for $type {
const N_BITS: u16 = $n_bits;
}
};
}
impl_for!(u8, 8);
impl_for!(i8, 8);
impl_for!(u16, 16);
impl_for!(i16, 16);
impl_for!(u32, 32);
impl_for!(i32, 32);
impl_for!(u64, 64);
impl_for!(i64, 64);
impl_for!(u128, 128);
impl_for!(i128, 128);