array_storage.rs - source
Description: Source of the Rust file `/Users/erlendbasso/.cargo/registry/src/github.com-1ecc6299db9ec823/nalgebra-0.32.1/src/base/array_storage.rs`.
Keywords: rust, rustlang, rust-lang

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    use std::fmt::{self, Debug, Formatter};
    // use std::hash::{Hash, Hasher};
    use std::ops::Mul;

    #[cfg(feature = "serde-serialize-no-std")]
    use serde::de::{Error, SeqAccess, Visitor};
    #[cfg(feature = "serde-serialize-no-std")]
    use serde::ser::SerializeSeq;
    #[cfg(feature = "serde-serialize-no-std")]
    use serde::{Deserialize, Deserializer, Serialize, Serializer};
    #[cfg(feature = "serde-serialize-no-std")]
    use std::marker::PhantomData;

    use crate::base::allocator::Allocator;
    use crate::base::default_allocator::DefaultAllocator;
    use crate::base::dimension::{Const, ToTypenum};
    use crate::base::storage::{IsContiguous, Owned, RawStorage, RawStorageMut, ReshapableStorage};
    use crate::base::Scalar;
    use crate::Storage;
    use std::mem;

    /*
     *
     * Static RawStorage.
     *
     */
    /// A array-based statically sized matrix data storage.
    #[repr(transparent)]
    #[derive(Copy, Clone, PartialEq, Eq, Hash)]
    #[cfg_attr(
        feature = "rkyv-serialize-no-std",
        derive(rkyv::Archive, rkyv::Serialize, rkyv::Deserialize),
        archive(
            as = "ArrayStorage<T::Archived, R, C>",
            bound(archive = "
            T: rkyv::Archive,
            [[T; R]; C]: rkyv::Archive<Archived = [[T::Archived; R]; C]>
        ")
        )
    )]
    #[cfg_attr(feature = "rkyv-serialize", derive(bytecheck::CheckBytes))]
    #[cfg_attr(feature = "cuda", derive(cust_core::DeviceCopy))]
    pub struct ArrayStorage<T, const R: usize, const C: usize>(pub [[T; R]; C]);

    impl<T, const R: usize, const C: usize> ArrayStorage<T, R, C> {
        /// Converts this array storage to a slice.
        #[inline]
        pub fn as_slice(&self) -> &[T] {
            // SAFETY: this is OK because ArrayStorage is contiguous.
            unsafe { self.as_slice_unchecked() }
        }

        /// Converts this array storage to a mutable slice.
        #[inline]
        pub fn as_mut_slice(&mut self) -> &mut [T] {
            // SAFETY: this is OK because ArrayStorage is contiguous.
            unsafe { self.as_mut_slice_unchecked() }
        }
    }

    // TODO: remove this once the stdlib implements Default for arrays.
    impl<T: Default, const R: usize, const C: usize> Default for ArrayStorage<T, R, C>
    where
        [[T; R]; C]: Default,
    {
        #[inline]
        fn default() -> Self {
            Self(Default::default())
        }
    }

    impl<T: Debug, const R: usize, const C: usize> Debug for ArrayStorage<T, R, C> {
        #[inline]
        fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
            self.0.fmt(fmt)
        }
    }

    unsafe impl<T, const R: usize, const C: usize> RawStorage<T, Const<R>, Const<C>>
        for ArrayStorage<T, R, C>
    {
        type RStride = Const<1>;
        type CStride = Const<R>;

        #[inline]
        fn ptr(&self) -> *const T {
            self.0.as_ptr() as *const T
        }

        #[inline]
        fn shape(&self) -> (Const<R>, Const<C>) {
            (Const, Const)
        }

        #[inline]
        fn strides(&self) -> (Self::RStride, Self::CStride) {
            (Const, Const)
        }

        #[inline]
        fn is_contiguous(&self) -> bool {
            true
        }

        #[inline]
        unsafe fn as_slice_unchecked(&self) -> &[T] {
            std::slice::from_raw_parts(self.ptr(), R * C)
        }
    }

    unsafe impl<T: Scalar, const R: usize, const C: usize> Storage<T, Const<R>, Const<C>>
        for ArrayStorage<T, R, C>
    where
        DefaultAllocator: Allocator<T, Const<R>, Const<C>, Buffer = Self>,
    {
        #[inline]
        fn into_owned(self) -> Owned<T, Const<R>, Const<C>>
        where
            DefaultAllocator: Allocator<T, Const<R>, Const<C>>,
        {
            self
        }

        #[inline]
        fn clone_owned(&self) -> Owned<T, Const<R>, Const<C>>
        where
            DefaultAllocator: Allocator<T, Const<R>, Const<C>>,
        {
            self.clone()
        }
    }

    unsafe impl<T, const R: usize, const C: usize> RawStorageMut<T, Const<R>, Const<C>>
        for ArrayStorage<T, R, C>
    {
        #[inline]
        fn ptr_mut(&mut self) -> *mut T {
            self.0.as_mut_ptr() as *mut T
        }

        #[inline]
        unsafe fn as_mut_slice_unchecked(&mut self) -> &mut [T] {
            std::slice::from_raw_parts_mut(self.ptr_mut(), R * C)
        }
    }

    unsafe impl<T, const R: usize, const C: usize> IsContiguous for ArrayStorage<T, R, C> {}

    impl<T, const R1: usize, const C1: usize, const R2: usize, const C2: usize>
        ReshapableStorage<T, Const<R1>, Const<C1>, Const<R2>, Const<C2>> for ArrayStorage<T, R1, C1>
    where
        T: Scalar,
        Const<R1>: ToTypenum,
        Const<C1>: ToTypenum,
        Const<R2>: ToTypenum,
        Const<C2>: ToTypenum,
        <Const<R1> as ToTypenum>::Typenum: Mul<<Const<C1> as ToTypenum>::Typenum>,
        <Const<R2> as ToTypenum>::Typenum: Mul<
            <Const<C2> as ToTypenum>::Typenum,
            Output = typenum::Prod<
                <Const<R1> as ToTypenum>::Typenum,
                <Const<C1> as ToTypenum>::Typenum,
            >,
        >,
    {
        type Output = ArrayStorage<T, R2, C2>;

        fn reshape_generic(self, _: Const<R2>, _: Const<C2>) -> Self::Output {
            unsafe {
                let data: [[T; R2]; C2] = mem::transmute_copy(&self.0);
                mem::forget(self.0);
                ArrayStorage(data)
            }
        }
    }

    /*
     *
     * Serialization.
     *
     */
    // XXX: open an issue for serde so that it allows the serialization/deserialization of all arrays?
    #[cfg(feature = "serde-serialize-no-std")]
    impl<T, const R: usize, const C: usize> Serialize for ArrayStorage<T, R, C>
    where
        T: Scalar + Serialize,
    {
        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
        {
            let mut serializer = serializer.serialize_seq(Some(R * C))?;

            for e in self.as_slice().iter() {
                serializer.serialize_element(e)?;
            }

            serializer.end()
        }
    }

    #[cfg(feature = "serde-serialize-no-std")]
    impl<'a, T, const R: usize, const C: usize> Deserialize<'a> for ArrayStorage<T, R, C>
    where
        T: Scalar + Deserialize<'a>,
    {
        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
        where
            D: Deserializer<'a>,
        {
            deserializer.deserialize_seq(ArrayStorageVisitor::new())
        }
    }

    #[cfg(feature = "serde-serialize-no-std")]
    /// A visitor that produces a matrix array.
    struct ArrayStorageVisitor<T, const R: usize, const C: usize> {
        marker: PhantomData<T>,
    }

    #[cfg(feature = "serde-serialize-no-std")]
    impl<T, const R: usize, const C: usize> ArrayStorageVisitor<T, R, C>
    where
        T: Scalar,
    {
        /// Construct a new sequence visitor.
        pub fn new() -> Self {
            ArrayStorageVisitor {
                marker: PhantomData,
            }
        }
    }

    #[cfg(feature = "serde-serialize-no-std")]
    impl<'a, T, const R: usize, const C: usize> Visitor<'a> for ArrayStorageVisitor<T, R, C>
    where
        T: Scalar + Deserialize<'a>,
    {
        type Value = ArrayStorage<T, R, C>;

        fn expecting(&self, formatter: &mut Formatter<'_>) -> fmt::Result {
            formatter.write_str("a matrix array")
        }

        #[inline]
        fn visit_seq<V>(self, mut visitor: V) -> Result<ArrayStorage<T, R, C>, V::Error>
        where
            V: SeqAccess<'a>,
        {
            let mut out: ArrayStorage<core::mem::MaybeUninit<T>, R, C> =
                DefaultAllocator::allocate_uninit(Const::<R>, Const::<C>);
            let mut curr = 0;

            while let Some(value) = visitor.next_element()? {
                *out.as_mut_slice()
                    .get_mut(curr)
                    .ok_or_else(|| V::Error::invalid_length(curr, &self))? =
                    core::mem::MaybeUninit::new(value);
                curr += 1;
            }

            if curr == R * C {
                // Safety: all the elements have been initialized.
                unsafe { Ok(<DefaultAllocator as Allocator<T, Const<R>, Const<C>>>::assume_init(out)) }
            } else {
                for i in 0..curr {
                    // Safety:
                    // - We couldn’t initialize the whole storage. Drop the ones we initialized.
                    unsafe { std::ptr::drop_in_place(out.as_mut_slice()[i].as_mut_ptr()) };
                }

                Err(V::Error::invalid_length(curr, &self))
            }
        }
    }

    #[cfg(feature = "bytemuck")]
    unsafe impl<T: Scalar + Copy + bytemuck::Zeroable, const R: usize, const C: usize>
        bytemuck::Zeroable for ArrayStorage<T, R, C>
    {
    }

    #[cfg(feature = "bytemuck")]
    unsafe impl<T: Scalar + Copy + bytemuck::Pod, const R: usize, const C: usize> bytemuck::Pod
        for ArrayStorage<T, R, C>
    {
    }