provekit-whir 0.1.1

use static_assertions::assert_impl_all;
use zerocopy::{FromBytes, IntoBytes, KnownLayout};

use super::{Codec, Decoding, Encoding, NargDeserialize, VerificationResult};

/// An empty object. Like `()` with a `Codec`.
pub struct Empty;

impl<T> Encoding<[T]> for Empty {
    fn encode(&self) -> impl AsRef<[T]> {
        []
    }
}

impl<T> Decoding<[T]> for Empty {
    type Repr = [T; 0];

    fn decode(_buf: Self::Repr) -> Self {
        Self
    }
}

impl NargDeserialize for Empty {
    fn deserialize_from_narg(_buf: &mut &[u8]) -> VerificationResult<Self> {
        Ok(Self)
    }
}

assert_impl_all!(Empty: Codec);

/// Wrapper because spongefish is missing NargDeserialize for `u64`.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Default, FromBytes, KnownLayout, IntoBytes)]
#[repr(transparent)]
pub struct U64(pub u64);

impl Encoding<[u8]> for U64 {
    fn encode(&self) -> impl AsRef<[u8]> {
        self.0.to_le_bytes()
    }
}

impl Decoding<[u8]> for U64 {
    type Repr = [u8; 8];

    fn decode(buf: Self::Repr) -> Self {
        Self(u64::from_le_bytes(buf))
    }
}

impl NargDeserialize for U64 {
    fn deserialize_from_narg(buf: &mut &[u8]) -> VerificationResult<Self> {
        NargDeserialize::deserialize_from_narg(buf)
            .map(u64::from_le_bytes)
            .map(Self)
    }
}

assert_impl_all!(U64: Codec);