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, D> CowArray<'_, A, D>
15where D: Dimension
16{
17    /// Returns `true` iff the array is the view (borrowed) variant.
18    pub fn is_view(&self) -> bool
19    {
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    {
26        self.data.is_owned()
27    }
28}
29
30impl<'a, A, D> From<ArrayView<'a, A, D>> for CowArray<'a, A, D>
31where D: Dimension
32{
33    fn from(view: ArrayView<'a, A, D>) -> CowArray<'a, A, D>
34    {
35        // safe because equivalent data
36        unsafe {
37            ArrayBase::from_data_ptr(CowRepr::View(view.data), view.parts.ptr)
38                .with_strides_dim(view.parts.strides, view.parts.dim)
39        }
40    }
41}
42
43impl<'a, A, D> From<Array<A, D>> for CowArray<'a, A, D>
44where D: Dimension
45{
46    fn from(array: Array<A, D>) -> CowArray<'a, A, D>
47    {
48        // safe because equivalent data
49        unsafe {
50            ArrayBase::from_data_ptr(CowRepr::Owned(array.data), array.parts.ptr)
51                .with_strides_dim(array.parts.strides, array.parts.dim)
52        }
53    }
54}
55
56impl<'a, A, Slice: ?Sized> From<&'a Slice> for CowArray<'a, A, Ix1>
57where 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    {
72        Self::from(ArrayView1::from(slice))
73    }
74}
75
76impl<'a, A, S, D> From<&'a ArrayBase<S, D>> for CowArray<'a, A, D>
77where
78    S: Data<Elem = A>,
79    D: Dimension,
80{
81    /// Create a read-only clone-on-write view of the array.
82    fn from(array: &'a ArrayBase<S, D>) -> Self
83    {
84        Self::from(array.view())
85    }
86}
ndarray/impl_cow.rs

ndarray/
impl_cow.rs
