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// Copyright 2022-2024 Gabriel Bjørnager Jensen.
use crate::deserialise::DStream;
use crate::error::Error;
use std::convert::Infallible;
use std::error::Error as StdError;
use std::mem::size_of;
use std::num::NonZero;
pub trait Deserialise: Sized {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>>;
}
macro_rules! impl_float {
($type:ty) => {
impl Deserialise for $type {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let data = stream
.take(size_of::<Self>())?
.try_into()
.unwrap();
Ok(Self::from_be_bytes(data))
}
}
};
}
macro_rules! impl_int {
($type:ty) => {
impl Deserialise for $type {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let data = stream
.take(size_of::<Self>())?
.try_into()
.unwrap();
Ok(Self::from_be_bytes(data))
}
}
impl Deserialise for NonZero<$type> {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
Ok(Option::<Self>::deserialise(stream)?
.ok_or(Error::NullInteger)?)
}
}
};
}
impl<T: Deserialise, const N: usize> Deserialise for [T; N] {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let len = usize::try_from(u64::deserialise(stream)?).unwrap();
if len != N { return Err(Box::new(Error::ArrayLengthMismatch { len, ok_len: N })) };
let mut buf = Vec::with_capacity(len);
for _ in 0x0..len { buf.push(Deserialise::deserialise(stream)?); }
// If we had used the checked unwrap, we would also
// have to require `T: Debug`.
Ok(unsafe { buf.try_into().unwrap_unchecked() })
}
}
impl Deserialise for () {
fn deserialise(_stream: &mut DStream) -> Result<Self, Box<dyn StdError>> { Ok(()) }
}
impl Deserialise for bool {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let value = u8::deserialise(stream)?;
match value {
0x00 => Ok(false),
0x01 => Ok(true),
_ => Err(Box::new(Error::InvalidBoolean { value }))
}
}
}
impl Deserialise for char {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let value = u32::deserialise(stream)?;
Self::from_u32(value)
.ok_or(Box::new(Error::InvalidCodePoint { value }))
}
}
impl Deserialise for Infallible {
fn deserialise(_stream: &mut DStream) -> Result<Self, Box<dyn StdError>> { unreachable!() }
}
impl<T: Deserialise> Deserialise for Option<T> {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let sign = bool::deserialise(stream)?;
if sign {
Ok(Some(T::deserialise(stream)?))
} else {
Ok(None)
}
}
}
impl<T: Deserialise, E: Deserialise> Deserialise for Result<T, E> {
fn deserialise(stream: &mut DStream) -> Result<Self, Box<dyn StdError>> {
let sign = bool::deserialise(stream)?;
let value = if sign {
Err(E::deserialise(stream)?)
} else {
Ok(T::deserialise(stream)?)
};
Ok(value)
}
}
impl_float!(f32);
impl_float!(f64);
impl_int!(i128);
impl_int!(i16);
impl_int!(i32);
impl_int!(i64);
impl_int!(i8);
impl_int!(u128);
impl_int!(u16);
impl_int!(u32);
impl_int!(u64);
impl_int!(u8);
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