Merge pull request #271 from rosslannen/feature/nalgebra-v0_34

Implement schema for nalgebra v0.34.

Author: jamesmunns

source/postcard-schema/Cargo.toml

@@ -64,6 +64,12 @@ version = "0.33.0"
 optional = true
 default-features = false
 
+[dependencies.nalgebra_v0_34]
+package = "nalgebra"
+version = "0.34.1"
+optional = true
+default-features = false
+
 [dependencies.fixed_v1_0]
 package = "fixed"
 version = "1.0"
@@ -95,6 +101,12 @@ version = "0.33.0"
 default-features = false
 features = ["serde-serialize-no-std"]
 
+[dev-dependencies.nalgebra_v0_34]
+package = "nalgebra"
+version = "0.34.1"
+default-features = false
+features = ["serde-serialize-no-std"]
+
 [features]
 default = []
 use-std = ["serde/std"]
@@ -111,5 +123,6 @@ heapless-v0_7 = ["heapless_v0_7"]
 heapless-v0_8 = ["heapless_v0_8"]
 heapless-v0_9 = ["heapless_v0_9"]
 nalgebra-v0_33 = ["nalgebra_v0_33"]
+nalgebra-v0_34 = ["nalgebra_v0_34"]
 serde-big-array-v0_5 = ["serde-big-array_v0_5"]
 uuid-v1_0 = ["uuid_v1_0"]

source/postcard-schema/src/impls/mod.rs

@@ -41,6 +41,10 @@ pub mod heapless_v0_9;
 #[cfg_attr(docsrs, doc(cfg(feature = "nalgebra-v0_33")))]
 pub mod nalgebra_v0_33;
 
+#[cfg(feature = "nalgebra-v0_34")]
+#[cfg_attr(docsrs, doc(cfg(feature = "nalgebra-v0_34")))]
+pub mod nalgebra_v0_34;
+
 #[cfg(feature = "serde-big-array-v0_5")]
 #[cfg_attr(docsrs, doc(cfg(feature = "serde-big-array-v0_5")))]
 pub mod serde_big_array_v0_5;

source/postcard-schema/src/impls/nalgebra_v0_34.rs

@@ -0,0 +1,58 @@
+//! Implementations of the [`Schema`] trait for the `nalgebra` crate v0.34
+
+use crate::{
+    schema::{DataModelType, NamedType},
+    Schema,
+};
+
+#[cfg_attr(docsrs, doc(cfg(feature = "nalgebra-v0_34")))]
+impl<T, const R: usize, const C: usize> Schema
+    for nalgebra_v0_34::Matrix<
+        T,
+        nalgebra_v0_34::Const<R>,
+        nalgebra_v0_34::Const<C>,
+        nalgebra_v0_34::ArrayStorage<T, R, C>,
+    >
+where
+    T: Schema + nalgebra_v0_34::Scalar,
+{
+    const SCHEMA: &'static NamedType = &NamedType {
+        name: "nalgebra::Matrix<T, R, C, ArrayStorage<T, R, C>>",
+        ty: &DataModelType::Tuple(flatten(&[[T::SCHEMA; R]; C])),
+    };
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "nalgebra-v0_34")))]
+impl<T: Schema> Schema for nalgebra_v0_34::Unit<T> {
+    const SCHEMA: &'static NamedType = T::SCHEMA;
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "nalgebra-v0_34")))]
+impl<T: Schema + nalgebra_v0_34::Scalar> Schema for nalgebra_v0_34::Quaternion<T> {
+    const SCHEMA: &'static NamedType = nalgebra_v0_34::Vector4::<T>::SCHEMA;
+}
+
+/// Const version of the const-unstable [`<[[T; N]]>::as_flattened()`]
+const fn flatten<T, const N: usize>(slice: &[[T; N]]) -> &[T] {
+    const {
+        assert!(size_of::<T>() != 0);
+    }
+    // SAFETY: `self.len() * N` cannot overflow because `self` is
+    // already in the address space.
+    let len = unsafe { slice.len().unchecked_mul(N) };
+    // SAFETY: `[T]` is layout-identical to `[T; N]`
+    unsafe { core::slice::from_raw_parts(slice.as_ptr().cast(), len) }
+}
+
+#[test]
+fn flattened() {
+    type T = nalgebra_v0_34::SMatrix<u8, 3, 3>;
+    assert_eq!(T::SCHEMA.ty, <[u8; 9]>::SCHEMA.ty);
+}
+
+#[test]
+fn smoke() {
+    let x = nalgebra_v0_34::SMatrix::<u8, 3, 3>::new(1, 2, 3, 4, 5, 6, 7, 8, 9);
+    let y = postcard::to_stdvec(&x).unwrap();
+    assert_eq!(&[1, 4, 7, 2, 5, 8, 3, 6, 9], y.as_slice());
+}