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hermes_simd_core/vec/
rkyv.rs

1//! rkyv zero-copy serialization support for AlignedVec.
2
3//! Zero-copy serialization support for aligned vectors using `rkyv`.
4
5use super::AlignedVec;
6use crate::align::Alignment;
7use rkyv::munge::munge;
8use rkyv::rancor::Fallible;
9use rkyv::ser::{Allocator, Writer};
10use rkyv::{Place, Portable};
11
12/// Archived representation of an `AlignedVec` used by `rkyv` zero-copy serialization.
13///
14/// Transparent over `ArchivedVec`, so portability and byte validity reduce to
15/// the element type's; both are derived rather than asserted by hand.
16#[derive(Portable, rkyv::bytecheck::CheckBytes)]
17#[bytecheck(crate = rkyv::bytecheck)]
18#[repr(transparent)]
19pub struct ArchivedAlignedVec<T> {
20    pub(crate) elements: rkyv::vec::ArchivedVec<T>,
21}
22
23/// Resolver type for `AlignedVec` serialization.
24pub struct AlignedVecResolver {
25    pub(crate) elements_resolver: rkyv::vec::VecResolver,
26}
27
28impl<T, Align> rkyv::Archive for AlignedVec<T, Align>
29where
30    T: rkyv::Archive,
31    Align: Alignment,
32{
33    type Archived = ArchivedAlignedVec<T::Archived>;
34    type Resolver = AlignedVecResolver;
35
36    #[inline]
37    fn resolve(&self, resolver: Self::Resolver, out: Place<Self::Archived>) {
38        // 0.8 projects the field through `Place`, so the offset the 0.7
39        // implementation computed by hand cannot drift from the layout.
40        munge!(let ArchivedAlignedVec { elements } = out);
41        rkyv::vec::ArchivedVec::resolve_from_slice(
42            self.as_slice(),
43            resolver.elements_resolver,
44            elements,
45        );
46    }
47}
48
49impl<T, Align, S> rkyv::Serialize<S> for AlignedVec<T, Align>
50where
51    T: rkyv::Serialize<S> + rkyv::Archive,
52    Align: Alignment,
53    S: Fallible + Allocator + Writer + ?Sized,
54{
55    #[inline]
56    fn serialize(&self, serializer: &mut S) -> Result<Self::Resolver, S::Error> {
57        let elements_resolver =
58            rkyv::vec::ArchivedVec::serialize_from_slice(self.as_slice(), serializer)?;
59        Ok(AlignedVecResolver { elements_resolver })
60    }
61}
62
63// The archived element type is not the native one -- `Archived<i32>` is
64// `i32_le` -- so the target element is a distinct parameter. The 0.7 bound
65// `T: Deserialize<T, D>` only compiled because the two coincided under native
66// endianness; naming them separately is what makes this correct rather than
67// accidentally well-typed.
68impl<T, U, Align, D> rkyv::Deserialize<AlignedVec<U, Align>, D> for ArchivedAlignedVec<T>
69where
70    T: rkyv::Deserialize<U, D>,
71    Align: Alignment,
72    D: Fallible + ?Sized,
73{
74    #[inline]
75    fn deserialize(&self, deserializer: &mut D) -> Result<AlignedVec<U, Align>, D::Error> {
76        let slice = self.elements.as_slice();
77        let mut v = AlignedVec::with_capacity(slice.len());
78        for x in slice {
79            v.push(x.deserialize(deserializer)?);
80        }
81        Ok(v)
82    }
83}