Merge pull request #145 from mulimoen/feature/ArrayReplace

Replace Array trait with const generics

Author: mulimoen

CHANGELOG.md

@@ -60,6 +60,8 @@
 - Const generics support (MSRV 1.51): `hdf5-types` now uses const generics for array types,
   allowing fixed-size arrays of arbitrary sizes.
 - The `ndarray` dependency has been updated to `0.15`.
+- `hdf5_types::Array` trait has been removed and replaced with const generics. String types
+  are now generic over size only: `FixedAscii<N>` and `FixedUnicode<N>`.
 
 ## 0.7.1
 

README.md

@@ -6,6 +6,7 @@ HDF5 for Rust.
 [![Latest Version](https://img.shields.io/crates/v/hdf5.svg)](https://crates.io/crates/hdf5)
 [![Documentation](https://docs.rs/hdf5/badge.svg)](https://docs.rs/hdf5)
 [![Changelog](https://img.shields.io/github/v/release/aldanor/hdf5-rust)](https://github.com/aldanor/hdf5-rust/blob/master/CHANGELOG.md)
+![hdf5: rustc 1.51+](https://img.shields.io/badge/hdf5-rustc_1.51+-lightblue.svg)
 [![Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
 
@@ -89,7 +90,7 @@ toolchains; macOS Catalina).
 ### Rust
 
 `hdf5` crate is tested continuously for all three official release channels, and
-requires a reasonably recent Rust compiler (e.g. of version 1.40 or newer).
+requires a reasonably recent Rust compiler (e.g. of version 1.51 or newer).
 
 ### HDF5
 

hdf5-derive/tests/test.rs

@@ -18,10 +18,10 @@ struct A {
 #[repr(C)]
 struct B {
     a: [A; 4],
-    b: FixedAscii<[u8; 8]>,
+    b: FixedAscii<8>,
     c: VarLenArray<f64>,
     d: bool,
-    e: FixedUnicode<[u8; 7]>,
+    e: FixedUnicode<7>,
     f: VarLenAscii,
     g: VarLenUnicode,
 }

hdf5-types/src/array.rs

@@ -5,34 +5,6 @@ use std::ops::Deref;
 use std::ptr;
 use std::slice;
 
-/* This trait is borrowed from arrayvec::Array (C) @bluss */
-pub unsafe trait Array: 'static {
-    type Item;
-
-    fn as_ptr(&self) -> *const Self::Item;
-    fn as_mut_ptr(&mut self) -> *mut Self::Item;
-    fn capacity() -> usize;
-}
-
-unsafe impl<T: 'static, const N: usize> Array for [T; N] {
-    type Item = T;
-
-    #[inline(always)]
-    fn as_ptr(&self) -> *const T {
-        self as *const _
-    }
-
-    #[inline(always)]
-    fn as_mut_ptr(&mut self) -> *mut T {
-        self as *mut _ as *mut _
-    }
-
-    #[inline(always)]
-    fn capacity() -> usize {
-        N
-    }
-}
-
 #[repr(C)]
 pub struct VarLenArray<T: Copy> {
     len: usize,
@@ -126,10 +98,10 @@ impl<T: Copy> From<VarLenArray<T>> for Vec<T> {
     }
 }
 
-impl<T: Copy, A: Array<Item = T>> From<A> for VarLenArray<T> {
+impl<T: Copy, const N: usize> From<[T; N]> for VarLenArray<T> {
     #[inline]
-    fn from(arr: A) -> VarLenArray<T> {
-        unsafe { VarLenArray::from_parts(arr.as_ptr(), A::capacity()) }
+    fn from(arr: [T; N]) -> VarLenArray<T> {
+        unsafe { VarLenArray::from_parts(arr.as_ptr(), arr.len()) }
     }
 }
 
@@ -156,10 +128,10 @@ impl<T: Copy + PartialEq> PartialEq<[T]> for VarLenArray<T> {
     }
 }
 
-impl<T: Copy + PartialEq, A: Array<Item = T>> PartialEq<A> for VarLenArray<T> {
+impl<T: Copy + PartialEq, const N: usize> PartialEq<[T; N]> for VarLenArray<T> {
     #[inline]
-    fn eq(&self, other: &A) -> bool {
-        self.as_slice() == unsafe { slice::from_raw_parts(other.as_ptr(), A::capacity()) }
+    fn eq(&self, other: &[T; N]) -> bool {
+        self.as_slice() == other
     }
 }
 
@@ -172,19 +144,10 @@ impl<T: Copy + fmt::Debug> fmt::Debug for VarLenArray<T> {
 
 #[cfg(test)]
 pub mod tests {
-    use super::{Array, VarLenArray};
+    use super::VarLenArray;
 
     type S = VarLenArray<u16>;
 
-    #[test]
-    pub fn test_array_trait() {
-        type T = [u32; 256];
-        assert_eq!(<T as Array>::capacity(), 256);
-        let mut arr = [1, 2, 3];
-        assert_eq!(arr.as_ptr(), &arr[0] as *const _);
-        assert_eq!(arr.as_mut_ptr(), &mut arr[0] as *mut _);
-    }
-
     #[test]
     pub fn test_vla_empty_default() {
         assert_eq!(&*S::default(), &[]);

hdf5-types/src/dyn_value.rs

@@ -803,8 +803,8 @@ mod tests {
     #[repr(C)]
     struct Data {
         points: VarLenArray<Point>,
-        fa: FixedAscii<[u8; 5]>,
-        fu: FixedUnicode<[u8; 5]>,
+        fa: FixedAscii<5>,
+        fu: FixedUnicode<5>,
         va: VarLenAscii,
         vu: VarLenUnicode,
     }

hdf5-types/src/h5type.rs

@@ -3,7 +3,7 @@ use std::mem;
 use std::os::raw::c_void;
 use std::ptr;
 
-use crate::array::{Array, VarLenArray};
+use crate::array::VarLenArray;
 use crate::string::{FixedAscii, FixedUnicode, VarLenAscii, VarLenUnicode};
 
 #[allow(non_camel_case_types)]
@@ -331,13 +331,10 @@ macro_rules! impl_tuple {
 
 impl_tuple! { A, B, C, D, E, F, G, H, I, J, K, L }
 
-unsafe impl<T: Array<Item = I>, I: H5Type> H5Type for T {
+unsafe impl<T: H5Type, const N: usize> H5Type for [T; N] {
     #[inline]
     fn type_descriptor() -> TypeDescriptor {
-        TypeDescriptor::FixedArray(
-            Box::new(<I as H5Type>::type_descriptor()),
-            <T as Array>::capacity(),
-        )
+        TypeDescriptor::FixedArray(Box::new(<T as H5Type>::type_descriptor()), N)
     }
 }
 
@@ -348,17 +345,17 @@ unsafe impl<T: Copy + H5Type> H5Type for VarLenArray<T> {
     }
 }
 
-unsafe impl<A: Array<Item = u8>> H5Type for FixedAscii<A> {
+unsafe impl<const N: usize> H5Type for FixedAscii<N> {
     #[inline]
     fn type_descriptor() -> TypeDescriptor {
-        TypeDescriptor::FixedAscii(A::capacity())
+        TypeDescriptor::FixedAscii(N)
     }
 }
 
-unsafe impl<A: Array<Item = u8>> H5Type for FixedUnicode<A> {
+unsafe impl<const N: usize> H5Type for FixedUnicode<N> {
     #[inline]
     fn type_descriptor() -> TypeDescriptor {
-        TypeDescriptor::FixedUnicode(A::capacity())
+        TypeDescriptor::FixedUnicode(N)
     }
 }
 
@@ -439,8 +436,8 @@ pub mod tests {
 
     #[test]
     pub fn test_string_types() {
-        type FA = FixedAscii<[u8; 16]>;
-        type FU = FixedUnicode<[u8; 32]>;
+        type FA = FixedAscii<16>;
+        type FU = FixedUnicode<32>;
         assert_eq!(FA::type_descriptor(), TD::FixedAscii(16));
         assert_eq!(FU::type_descriptor(), TD::FixedUnicode(32));
         assert_eq!(VarLenAscii::type_descriptor(), TD::VarLenAscii);

hdf5-types/src/lib.rs

@@ -19,7 +19,7 @@ pub mod dyn_value;
 mod h5type;
 mod string;
 
-pub use self::array::{Array, VarLenArray};
+pub use self::array::VarLenArray;
 pub use self::dyn_value::{DynValue, OwnedDynValue};
 pub use self::h5type::{
     CompoundField, CompoundType, EnumMember, EnumType, FloatSize, H5Type, IntSize, TypeDescriptor,