extended-isolation-forest 0.2.0

use std::{convert::TryInto, marker::PhantomData};

use serde::{
    de::{SeqAccess, Visitor},
    ser::SerializeTuple,
    Deserialize, Deserializer, Serialize, Serializer,
};

// from https://github.com/serde-rs/serde/issues/1937#issuecomment-812137971

pub fn serialize<S: Serializer, T: Serialize, const N: usize>(
    data: &[T; N],
    ser: S,
) -> Result<S::Ok, S::Error> {
    let mut s = ser.serialize_tuple(N)?;
    for item in data {
        s.serialize_element(item)?;
    }
    s.end()
}

struct ArrayVisitor<T, const N: usize>(PhantomData<T>);

impl<'de, T, const N: usize> Visitor<'de> for ArrayVisitor<T, N>
where
    T: Deserialize<'de>,
{
    type Value = [T; N];

    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
        formatter.write_str(&format!("an array of length {}", N))
    }

    #[inline]
    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
    where
        A: SeqAccess<'de>,
    {
        // can be optimized using MaybeUninit
        let mut data = Vec::with_capacity(N);
        for _ in 0..N {
            match (seq.next_element())? {
                Some(val) => data.push(val),
                None => return Err(serde::de::Error::invalid_length(N, &self)),
            }
        }
        match data.try_into() {
            Ok(arr) => Ok(arr),
            Err(_) => unreachable!(),
        }
    }
}

pub fn deserialize<'de, D, T, const N: usize>(deserializer: D) -> Result<[T; N], D::Error>
where
    D: Deserializer<'de>,
    T: Deserialize<'de>,
{
    deserializer.deserialize_tuple(N, ArrayVisitor::<T, N>(PhantomData))
}