ferray_core/array/
view_mut.rs

1// ferray-core: Mutable array view — ArrayViewMut<'a, T, D> (REQ-3)
2
3use crate::dimension::Dimension;
4use crate::dtype::Element;
5use crate::layout::MemoryLayout;
6
7use super::ArrayFlags;
8use super::owned::Array;
9
10/// A mutable, borrowed view into an existing array's data.
11///
12/// This is a zero-copy mutable slice. The lifetime `'a` ties this view
13/// to the source array, and Rust's borrow checker ensures exclusivity.
14pub struct ArrayViewMut<'a, T: Element, D: Dimension> {
15    pub(crate) inner: ndarray::ArrayViewMut<'a, T, D::NdarrayDim>,
16    pub(crate) dim: D,
17}
18
19impl<'a, T: Element, D: Dimension> ArrayViewMut<'a, T, D> {
20    /// Create from an ndarray mutable view. Crate-internal.
21    pub(crate) fn from_ndarray(inner: ndarray::ArrayViewMut<'a, T, D::NdarrayDim>) -> Self {
22        let dim = D::from_ndarray_dim(&inner.raw_dim());
23        Self { inner, dim }
24    }
25
26    /// Shape as a slice.
27    #[inline]
28    pub fn shape(&self) -> &[usize] {
29        self.inner.shape()
30    }
31
32    /// Number of dimensions.
33    #[inline]
34    pub fn ndim(&self) -> usize {
35        self.dim.ndim()
36    }
37
38    /// Total number of elements.
39    #[inline]
40    pub fn size(&self) -> usize {
41        self.inner.len()
42    }
43
44    /// Whether the view has zero elements.
45    #[inline]
46    pub fn is_empty(&self) -> bool {
47        self.inner.is_empty()
48    }
49
50    /// Strides as a slice.
51    #[inline]
52    pub fn strides(&self) -> &[isize] {
53        self.inner.strides()
54    }
55
56    /// Raw pointer to the first element.
57    #[inline]
58    pub fn as_ptr(&self) -> *const T {
59        self.inner.as_ptr()
60    }
61
62    /// Mutable raw pointer to the first element.
63    #[inline]
64    pub fn as_mut_ptr(&mut self) -> *mut T {
65        self.inner.as_mut_ptr()
66    }
67
68    /// Try to get a contiguous slice.
69    pub fn as_slice(&self) -> Option<&[T]> {
70        self.inner.as_slice()
71    }
72
73    /// Try to get a contiguous mutable slice.
74    pub fn as_slice_mut(&mut self) -> Option<&mut [T]> {
75        self.inner.as_slice_mut()
76    }
77
78    /// Memory layout.
79    pub fn layout(&self) -> MemoryLayout {
80        if self.inner.is_standard_layout() {
81            MemoryLayout::C
82        } else {
83            let shape = self.dim.as_slice();
84            let strides: Vec<isize> = self.inner.strides().to_vec();
85            crate::layout::detect_layout(shape, &strides)
86        }
87    }
88
89    /// Return a reference to the internal dimension descriptor.
90    #[inline]
91    pub fn dim(&self) -> &D {
92        &self.dim
93    }
94
95    /// Array flags for this mutable view.
96    pub fn flags(&self) -> ArrayFlags {
97        let layout = self.layout();
98        ArrayFlags {
99            c_contiguous: layout.is_c_contiguous(),
100            f_contiguous: layout.is_f_contiguous(),
101            owndata: false,
102            writeable: true,
103        }
104    }
105}
106
107// Create an ArrayViewMut from an owned Array
108impl<T: Element, D: Dimension> Array<T, D> {
109    /// Create a mutable view of this array.
110    pub fn view_mut(&mut self) -> ArrayViewMut<'_, T, D> {
111        ArrayViewMut::from_ndarray(self.inner.view_mut())
112    }
113}
114
115#[cfg(test)]
116mod tests {
117    use super::*;
118    use crate::dimension::Ix1;
119
120    #[test]
121    fn view_mut_from_owned() {
122        let mut arr = Array::<f64, Ix1>::from_vec(Ix1::new([3]), vec![1.0, 2.0, 3.0]).unwrap();
123        let v = arr.view_mut();
124        assert_eq!(v.shape(), &[3]);
125        assert!(v.flags().writeable);
126        assert!(!v.flags().owndata);
127    }
128
129    #[test]
130    fn view_mut_modify() {
131        let mut arr = Array::<f64, Ix1>::from_vec(Ix1::new([3]), vec![1.0, 2.0, 3.0]).unwrap();
132        {
133            let mut v = arr.view_mut();
134            if let Some(s) = v.as_slice_mut() {
135                s[0] = 99.0;
136            }
137        }
138        assert_eq!(arr.as_slice().unwrap()[0], 99.0);
139    }
140}
ferray_core/array/view_mut.rs

ferray_core/array/
view_mut.rs
