1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
// Copyright 2014-2016 bluss and ndarray developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::hash;
use std::iter::FromIterator;
use std::iter::IntoIterator;
use std::mem;
use std::ops::{Index, IndexMut};
use alloc::boxed::Box;
use alloc::vec::Vec;

use crate::imp_prelude::*;
use crate::iter::{Iter, IterMut};
use crate::NdIndex;

use crate::numeric_util;
use crate::{FoldWhile, Zip};

#[cold]
#[inline(never)]
pub(crate) fn array_out_of_bounds() -> ! {
    panic!("ndarray: index out of bounds");
}

#[inline(always)]
pub fn debug_bounds_check<S, D, I>(_a: &ArrayBase<S, D>, _index: &I)
where
    D: Dimension,
    I: NdIndex<D>,
    S: Data,
{
    debug_bounds_check!(_a, *_index);
}

/// Access the element at **index**.
///
/// **Panics** if index is out of bounds.
impl<S, D, I> Index<I> for ArrayBase<S, D>
where
    D: Dimension,
    I: NdIndex<D>,
    S: Data,
{
    type Output = S::Elem;
    #[inline]
    fn index(&self, index: I) -> &S::Elem {
        debug_bounds_check!(self, index);
        unsafe {
            &*self.ptr.as_ptr().offset(
                index
                    .index_checked(&self.dim, &self.strides)
                    .unwrap_or_else(|| array_out_of_bounds()),
            )
        }
    }
}

/// Access the element at **index** mutably.
///
/// **Panics** if index is out of bounds.
impl<S, D, I> IndexMut<I> for ArrayBase<S, D>
where
    D: Dimension,
    I: NdIndex<D>,
    S: DataMut,
{
    #[inline]
    fn index_mut(&mut self, index: I) -> &mut S::Elem {
        debug_bounds_check!(self, index);
        unsafe {
            &mut *self.as_mut_ptr().offset(
                index
                    .index_checked(&self.dim, &self.strides)
                    .unwrap_or_else(|| array_out_of_bounds()),
            )
        }
    }
}

/// Return `true` if the array shapes and all elements of `self` and
/// `rhs` are equal. Return `false` otherwise.
impl<A, B, S, S2, D> PartialEq<ArrayBase<S2, D>> for ArrayBase<S, D>
where
    A: PartialEq<B>,
    S: Data<Elem = A>,
    S2: Data<Elem = B>,
    D: Dimension,
{
    fn eq(&self, rhs: &ArrayBase<S2, D>) -> bool {
        if self.shape() != rhs.shape() {
            return false;
        }
        if let Some(self_s) = self.as_slice() {
            if let Some(rhs_s) = rhs.as_slice() {
                return numeric_util::unrolled_eq(self_s, rhs_s);
            }
        }
        Zip::from(self)
            .and(rhs)
            .fold_while(true, |_, a, b| {
                if a != b {
                    FoldWhile::Done(false)
                } else {
                    FoldWhile::Continue(true)
                }
            })
            .into_inner()
    }
}

/// Return `true` if the array shapes and all elements of `self` and
/// `rhs` are equal. Return `false` otherwise.
impl<'a, A, B, S, S2, D> PartialEq<&'a ArrayBase<S2, D>> for ArrayBase<S, D>
where
    A: PartialEq<B>,
    S: Data<Elem = A>,
    S2: Data<Elem = B>,
    D: Dimension,
{
    fn eq(&self, rhs: &&ArrayBase<S2, D>) -> bool {
        *self == **rhs
    }
}

/// Return `true` if the array shapes and all elements of `self` and
/// `rhs` are equal. Return `false` otherwise.
impl<'a, A, B, S, S2, D> PartialEq<ArrayBase<S2, D>> for &'a ArrayBase<S, D>
where
    A: PartialEq<B>,
    S: Data<Elem = A>,
    S2: Data<Elem = B>,
    D: Dimension,
{
    fn eq(&self, rhs: &ArrayBase<S2, D>) -> bool {
        **self == *rhs
    }
}

impl<S, D> Eq for ArrayBase<S, D>
where
    D: Dimension,
    S: Data,
    S::Elem: Eq,
{
}

impl<A, S> From<Box<[A]>> for ArrayBase<S, Ix1>
where
    S: DataOwned<Elem = A>,
{
    /// Create a one-dimensional array from a boxed slice (no copying needed).
    ///
    /// **Panics** if the length is greater than `isize::MAX`.
    fn from(b: Box<[A]>) -> Self {
        Self::from_vec(b.into_vec())
    }
}

impl<A, S> From<Vec<A>> for ArrayBase<S, Ix1>
where
    S: DataOwned<Elem = A>,
{
    /// Create a one-dimensional array from a vector (no copying needed).
    ///
    /// **Panics** if the length is greater than `isize::MAX`.
    ///
    /// ```rust
    /// use ndarray::Array;
    ///
    /// let array = Array::from(vec![1., 2., 3., 4.]);
    /// ```
    fn from(v: Vec<A>) -> Self {
        Self::from_vec(v)
    }
}

impl<A, S> FromIterator<A> for ArrayBase<S, Ix1>
where
    S: DataOwned<Elem = A>,
{
    /// Create a one-dimensional array from an iterable.
    ///
    /// **Panics** if the length is greater than `isize::MAX`.
    ///
    /// ```rust
    /// use ndarray::{Array, arr1};
    ///
    /// // Either use `from_iter` directly or use `Iterator::collect`.
    /// let array = Array::from_iter((0..5).map(|x| x * x));
    /// assert!(array == arr1(&[0, 1, 4, 9, 16]))
    /// ```
    fn from_iter<I>(iterable: I) -> ArrayBase<S, Ix1>
    where
        I: IntoIterator<Item = A>,
    {
        Self::from_iter(iterable)
    }
}

impl<'a, S, D> IntoIterator for &'a ArrayBase<S, D>
where
    D: Dimension,
    S: Data,
{
    type Item = &'a S::Elem;
    type IntoIter = Iter<'a, S::Elem, D>;

    fn into_iter(self) -> Self::IntoIter {
        self.iter()
    }
}

impl<'a, S, D> IntoIterator for &'a mut ArrayBase<S, D>
where
    D: Dimension,
    S: DataMut,
{
    type Item = &'a mut S::Elem;
    type IntoIter = IterMut<'a, S::Elem, D>;

    fn into_iter(self) -> Self::IntoIter {
        self.iter_mut()
    }
}

impl<'a, A, D> IntoIterator for ArrayView<'a, A, D>
where
    D: Dimension,
{
    type Item = &'a A;
    type IntoIter = Iter<'a, A, D>;

    fn into_iter(self) -> Self::IntoIter {
        self.into_iter_()
    }
}

impl<'a, A, D> IntoIterator for ArrayViewMut<'a, A, D>
where
    D: Dimension,
{
    type Item = &'a mut A;
    type IntoIter = IterMut<'a, A, D>;

    fn into_iter(self) -> Self::IntoIter {
        self.into_iter_()
    }
}

impl<S, D> hash::Hash for ArrayBase<S, D>
where
    D: Dimension,
    S: Data,
    S::Elem: hash::Hash,
{
    // Note: elements are hashed in the logical order
    fn hash<H: hash::Hasher>(&self, state: &mut H) {
        self.shape().hash(state);
        if let Some(self_s) = self.as_slice() {
            hash::Hash::hash_slice(self_s, state);
        } else {
            for row in self.rows() {
                if let Some(row_s) = row.as_slice() {
                    hash::Hash::hash_slice(row_s, state);
                } else {
                    for elt in row {
                        elt.hash(state)
                    }
                }
            }
        }
    }
}

// NOTE: ArrayBase keeps an internal raw pointer that always
// points into the storage. This is Sync & Send as long as we
// follow the usual inherited mutability rules, as we do with
// Vec, &[] and &mut []

/// `ArrayBase` is `Sync` when the storage type is.
unsafe impl<S, D> Sync for ArrayBase<S, D>
where
    S: Sync + Data,
    D: Sync,
{
}

/// `ArrayBase` is `Send` when the storage type is.
unsafe impl<S, D> Send for ArrayBase<S, D>
where
    S: Send + Data,
    D: Send,
{
}

#[cfg(any(feature = "serde"))]
// Use version number so we can add a packed format later.
pub const ARRAY_FORMAT_VERSION: u8 = 1u8;

// use "raw" form instead of type aliases here so that they show up in docs
/// Implementation of `ArrayView::from(&S)` where `S` is a slice or sliceable.
impl<'a, A, Slice: ?Sized> From<&'a Slice> for ArrayView<'a, A, Ix1>
where
    Slice: AsRef<[A]>,
{
    /// Create a one-dimensional read-only array view of the data in `slice`.
    ///
    /// **Panics** if the slice length is greater than `isize::MAX`.
    fn from(slice: &'a Slice) -> Self {
        let xs = slice.as_ref();
        if mem::size_of::<A>() == 0 {
            assert!(
                xs.len() <= ::std::isize::MAX as usize,
                "Slice length must fit in `isize`.",
            );
        }
        unsafe { Self::from_shape_ptr(xs.len(), xs.as_ptr()) }
    }
}

/// Implementation of `ArrayView::from(&A)` where `A` is an array.
impl<'a, A, S, D> From<&'a ArrayBase<S, D>> for ArrayView<'a, A, D>
where
    S: Data<Elem = A>,
    D: Dimension,
{
    /// Create a read-only array view of the array.
    fn from(array: &'a ArrayBase<S, D>) -> Self {
        array.view()
    }
}

/// Implementation of `ArrayViewMut::from(&mut S)` where `S` is a slice or sliceable.
impl<'a, A, Slice: ?Sized> From<&'a mut Slice> for ArrayViewMut<'a, A, Ix1>
where
    Slice: AsMut<[A]>,
{
    /// Create a one-dimensional read-write array view of the data in `slice`.
    ///
    /// **Panics** if the slice length is greater than `isize::MAX`.
    fn from(slice: &'a mut Slice) -> Self {
        let xs = slice.as_mut();
        if mem::size_of::<A>() == 0 {
            assert!(
                xs.len() <= ::std::isize::MAX as usize,
                "Slice length must fit in `isize`.",
            );
        }
        unsafe { Self::from_shape_ptr(xs.len(), xs.as_mut_ptr()) }
    }
}

/// Implementation of `ArrayViewMut::from(&mut A)` where `A` is an array.
impl<'a, A, S, D> From<&'a mut ArrayBase<S, D>> for ArrayViewMut<'a, A, D>
where
    S: DataMut<Elem = A>,
    D: Dimension,
{
    /// Create a read-write array view of the array.
    fn from(array: &'a mut ArrayBase<S, D>) -> Self {
        array.view_mut()
    }
}

impl<A, D> From<Array<A, D>> for ArcArray<A, D>
where
    D: Dimension,
{
    fn from(arr: Array<A, D>) -> ArcArray<A, D> {
        arr.into_shared()
    }
}

/// Argument conversion into an array view
///
/// The trait is parameterized over `A`, the element type, and `D`, the
/// dimensionality of the array. `D` defaults to one-dimensional.
///
/// Use `.into()` to do the conversion.
///
/// ```
/// use ndarray::AsArray;
///
/// fn sum<'a, V: AsArray<'a, f64>>(data: V) -> f64 {
///     let array_view = data.into();
///     array_view.sum()
/// }
///
/// assert_eq!(
///     sum(&[1., 2., 3.]),
///     6.
/// );
///
/// ```
pub trait AsArray<'a, A: 'a, D = Ix1>: Into<ArrayView<'a, A, D>>
where
    D: Dimension,
{
}
impl<'a, A: 'a, D, T> AsArray<'a, A, D> for T
where
    T: Into<ArrayView<'a, A, D>>,
    D: Dimension,
{
}

/// Create an owned array with a default state.
///
/// The array is created with dimension `D::default()`, which results
/// in for example dimensions `0` and `(0, 0)` with zero elements for the
/// one-dimensional and two-dimensional cases respectively.
///
/// The default dimension for `IxDyn` is `IxDyn(&[0])` (array has zero
/// elements). And the default for the dimension `()` is `()` (array has
/// one element).
///
/// Since arrays cannot grow, the intention is to use the default value as
/// placeholder.
impl<A, S, D> Default for ArrayBase<S, D>
where
    S: DataOwned<Elem = A>,
    D: Dimension,
    A: Default,
{
    // NOTE: We can implement Default for non-zero dimensional array views by
    // using an empty slice, however we need a trait for nonzero Dimension.
    fn default() -> Self {
        ArrayBase::default(D::default())
    }
}