ndarray/
impl_cow.rs

1// Copyright 2019 ndarray developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9use crate::imp_prelude::*;
10
11/// Methods specific to `CowArray`.
12///
13/// ***See also all methods for [`ArrayBase`]***
14impl<'a, A, D> CowArray<'a, A, D>
15where
16    D: Dimension,
17{
18    /// Returns `true` iff the array is the view (borrowed) variant.
19    pub fn is_view(&self) -> bool {
20        self.data.is_view()
21    }
22
23    /// Returns `true` iff the array is the owned variant.
24    pub fn is_owned(&self) -> bool {
25        self.data.is_owned()
26    }
27}
28
29impl<'a, A, D> From<ArrayView<'a, A, D>> for CowArray<'a, A, D>
30where
31    D: Dimension,
32{
33    fn from(view: ArrayView<'a, A, D>) -> CowArray<'a, A, D> {
34        // safe because equivalent data
35        unsafe {
36            ArrayBase::from_data_ptr(CowRepr::View(view.data), view.ptr)
37                .with_strides_dim(view.strides, view.dim)
38        }
39    }
40}
41
42impl<'a, A, D> From<Array<A, D>> for CowArray<'a, A, D>
43where
44    D: Dimension,
45{
46    fn from(array: Array<A, D>) -> CowArray<'a, A, D> {
47        // safe because equivalent data
48        unsafe {
49            ArrayBase::from_data_ptr(CowRepr::Owned(array.data), array.ptr)
50                .with_strides_dim(array.strides, array.dim)
51        }
52    }
53}
54
55impl<'a, A, Slice: ?Sized> From<&'a Slice> for CowArray<'a, A, Ix1>
56where
57    Slice: AsRef<[A]>,
58{
59    /// Create a one-dimensional clone-on-write view of the data in `slice`.
60    ///
61    /// **Panics** if the slice length is greater than [`isize::MAX`].
62    ///
63    /// ```
64    /// use ndarray::{array, CowArray};
65    ///
66    /// let array = CowArray::from(&[1., 2., 3., 4.]);
67    /// assert!(array.is_view());
68    /// assert_eq!(array, array![1., 2., 3., 4.]);
69    /// ```
70    fn from(slice: &'a Slice) -> Self {
71        Self::from(ArrayView1::from(slice))
72    }
73}
74
75impl<'a, A, S, D> From<&'a ArrayBase<S, D>> for CowArray<'a, A, D>
76where
77    S: Data<Elem = A>,
78    D: Dimension,
79{
80    /// Create a read-only clone-on-write view of the array.
81    fn from(array: &'a ArrayBase<S, D>) -> Self {
82        Self::from(array.view())
83    }
84}
ndarray/impl_cow.rs

ndarray/
impl_cow.rs
