Fortran layout bigarray view

src/types.rs

@@ -468,7 +468,9 @@ pub mod bigarray {
 
 #[cfg(all(feature = "bigarray-ext", not(feature = "no-std")))]
 pub(crate) mod bigarray_ext {
-    use ndarray::{ArrayView2, ArrayView3, ArrayViewMut2, ArrayViewMut3, Dimension};
+    use ndarray::{
+        ArrayView2, ArrayView3, ArrayViewMut2, ArrayViewMut3, Dimension, Shape, ShapeBuilder,
+    };
 
     use core::{marker::PhantomData, mem, ptr, slice};
 
@@ -488,13 +490,17 @@ pub(crate) mod bigarray_ext {
         /// Returns array view
         pub fn view(&self) -> ArrayView2<T> {
             let ba = unsafe { self.0.custom_ptr_val::<bigarray::Bigarray>() };
-            unsafe { ArrayView2::from_shape_ptr(self.shape(), (*ba).data as *const T) }
+            unsafe {
+                ArrayView2::from_shape_ptr(build_shape(ba, self.shape()), (*ba).data as *const T)
+            }
         }
 
         /// Returns mutable array view
         pub fn view_mut(&mut self) -> ArrayViewMut2<T> {
             let ba = unsafe { self.0.custom_ptr_val::<bigarray::Bigarray>() };
-            unsafe { ArrayViewMut2::from_shape_ptr(self.shape(), (*ba).data as *mut T) }
+            unsafe {
+                ArrayViewMut2::from_shape_ptr(build_shape(ba, self.shape()), (*ba).data as *mut T)
+            }
         }
 
         /// Returns the shape of `self`
@@ -568,13 +574,17 @@ pub(crate) mod bigarray_ext {
         /// Returns array view
         pub fn view(&self) -> ArrayView3<T> {
             let ba = unsafe { self.0.custom_ptr_val::<bigarray::Bigarray>() };
-            unsafe { ArrayView3::from_shape_ptr(self.shape(), (*ba).data as *const T) }
+            unsafe {
+                ArrayView3::from_shape_ptr(build_shape(ba, self.shape()), (*ba).data as *const T)
+            }
         }
 
         /// Returns mutable array view
         pub fn view_mut(&mut self) -> ArrayViewMut3<T> {
             let ba = unsafe { self.0.custom_ptr_val::<bigarray::Bigarray>() };
-            unsafe { ArrayViewMut3::from_shape_ptr(self.shape(), (*ba).data as *mut T) }
+            unsafe {
+                ArrayViewMut3::from_shape_ptr(build_shape(ba, self.shape()), (*ba).data as *mut T)
+            }
         }
 
         /// Returns the shape of `self`
@@ -638,4 +648,15 @@ pub(crate) mod bigarray_ext {
             array
         }
     }
+
+    fn build_shape<S: ShapeBuilder>(
+        ba: *const bigarray::Bigarray,
+        shape: S,
+    ) -> Shape<<S as ShapeBuilder>::Dim> {
+        if unsafe { (*ba).is_fortran() } {
+            shape.f()
+        } else {
+            shape.into_shape()
+        }
+    }
 }

sys/src/bigarray.rs

@@ -21,6 +21,13 @@ pub struct Bigarray {
     pub dim: [Intnat; 0],
 }
 
+impl Bigarray {
+    /// Returns true if array is Fortran contiguous
+    pub fn is_fortran(&self) -> bool {
+        (self.flags & Layout::FORTRAN_LAYOUT as isize) != 0
+    }
+}
+
 #[allow(non_camel_case_types)]
 pub enum Managed {
     EXTERNAL = 0,         /* Data is not allocated by OCaml */
@@ -47,6 +54,12 @@ pub enum Kind {
     KIND_MASK = 0xFF,  /* Mask for kind in flags field */
 }
 
+#[allow(non_camel_case_types)]
+pub enum Layout {
+    C_LAYOUT = 0,           /* Row major, indices start at 0 */
+    FORTRAN_LAYOUT = 0x100, /* Column major, indices start at 1 */
+}
+
 extern "C" {
     pub fn malloc(size: usize) -> Data;
     pub fn caml_ba_alloc(flags: i32, num_dims: i32, data: Data, dim: *const i32) -> Value;