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
use crate::{
iter::IterMove, util::transmute::extremely_unsafe_transmute, Array, ArrayWrapper, SizeError,
};
/// Extension on arrays that provide additional functions.
pub trait ArrayExt: Array {
/// Creates iterator which moves elements out of array.
///
/// See also: [IterMove](crate::iter::IterMove)
#[inline]
fn iter_move(self) -> IterMove<Self> {
IterMove::new(self)
}
/// ## Example
/// ```
/// use arraylib::ArrayExt;
///
/// let arr: [_; 6] = [1, 2, 3].concat_arr([4, 5, 6]);
/// assert_eq!(arr, [1, 2, 3, 4, 5, 6])
/// ```
///
/// ## Panics
///
/// Panics if `Self::SIZE` + `A::SIZE` != `R::SIZE`:
///
/// ```should_panic
/// use arraylib::ArrayExt;
///
/// let arr: [_; 4] = [1, 2, 3].concat_arr([4, 5, 6]);
/// ```
#[inline]
fn concat_arr<A, R>(self, other: A) -> R
where
A: Array<Item = Self::Item>,
R: Array<Item = Self::Item>,
{
unsafe {
// Because of lack of const generics we need to assert this in runtime :(
//
// It's also possible to add trait like `ArrayConcat<A> { type Output }` but
// this leads to A LOT of impls and SLOW compile times.
assert_eq!(Self::SIZE + A::SIZE, R::SIZE);
#[repr(C, packed)]
struct Both<Slf, A>(Slf, A);
// ## Safety
//
// We know that all `Self`, `A` and `R` are arrays.
// Also we know that `Self::SIZE + A::SIZE == R::SIZE`, that means that we can
// concat `Self` with `A` and we'll obtain `R`.
//
// Because of fact that all types are arrays (and fact that `Both` is
// `#[repr(C, packed)]`), we know that `Both<Self, A>` is equal to `R`, so we
// can safely transmute one into another.
let both = Both(self, other);
extremely_unsafe_transmute::<Both<Self, A>, R>(both)
}
}
/// Splits self into 2 arrays
///
/// ## Example
/// ```
/// use arraylib::ArrayExt;
///
/// let arr = [1, 2, 3, 4, 5];
/// let (head, tail) = arr.split_arr::<[_; 2], [_; 3]>();
///
/// assert_eq!(head, [1, 2]);
/// assert_eq!(tail, [3, 4, 5]);
/// ```
#[inline]
fn split_arr<A, B>(self) -> (A, B)
where
A: Array<Item = Self::Item>,
B: Array<Item = Self::Item>,
{
unsafe {
// Because of lack of const generics we need to assert this in runtime :(
//
// It's also possible to add trait like `ArraySplit<A, B> { ... }` but this
// leads to A LOT of impls and SLOW compile times.
assert_eq!(Self::SIZE, A::SIZE + B::SIZE);
#[repr(C, packed)]
struct Both<A, B>(A, B);
// ## Safety
//
// We know that all `Self`, `A` and `B` are arrays.
// Also we know that `Self::SIZE, A::SIZE + B::SIZE`, that means that we can
// split `Self` into `A` and `B`.
//
// Because of fact that all types are arrays (and fact that `Both` is
// `#[repr(C, packed)]`), we know that `Both<Self, A>` is equal to `R`, so we
// can safely transmute one into another.
let Both(a, b): Both<A, B> = extremely_unsafe_transmute::<Self, Both<A, B>>(self);
(a, b)
}
}
/// Converts `self` into an array. This function will return `Some(_)` if
/// sizes of `Self` and `A` are the same and `None` otherwise.
///
/// ## Example
/// ```
/// use arraylib::{Array, ArrayExt};
///
/// fn function_optimized_for_8(_: [i32; 8]) {
/// /* ... */
/// }
///
/// fn general<A>(array: A)
/// where
/// A: Array<Item = i32>,
/// {
/// match array.into_array::<[i32; 8]>() {
/// Ok(array) => function_optimized_for_8(array),
/// Err(array) => { /* here `array` is of type `A` */ },
/// }
/// }
/// ```
#[inline]
fn into_array<A>(self) -> Result<A, SizeError<Self>>
where
A: Array<Item = Self::Item>,
{
let slf = SizeError::expect(Self::SIZE, A::SIZE, self)?;
// ## Safety
//
// Item types and sizes are same for both `Self` and `A`, so it's the same type.
Ok(unsafe { extremely_unsafe_transmute::<Self, A>(slf) })
}
/// Copies `self` into a new `Vec`.
///
/// ## Examples
///
/// ```
/// use arraylib::{Array, ArrayExt};
///
/// fn generic<A>(arr: A)
/// where
/// A: Array,
/// A::Item: Clone,
/// {
/// let x = arr.to_vec();
/// // Here, `arr` and `x` can be modified independently.
/// }
/// ```
///
/// See also: [`[T]::to_vec`](https://doc.rust-lang.org/std/primitive.slice.html#method.to_vec)
#[cfg(feature = "alloc")]
#[inline]
fn to_vec(&self) -> alloc::vec::Vec<Self::Item>
where
Self::Item: Clone,
{
self.as_slice().to_vec()
}
/// Converts `self` into a vector without clones.
///
/// The resulting vector can be converted back into a box via
/// `Vec<T>`'s `into_boxed_slice` method.
///
/// ## Examples
///
/// ```
/// use arraylib::ArrayExt;
///
/// let s = [10, 40, 30];
/// let x = s.into_vec();
/// // `s` cannot be used anymore because it has been converted into `x`.
///
/// assert_eq!(x, vec![10, 40, 30]);
/// ```
///
/// See also: [`[T]::in to_vec`](https://doc.rust-lang.org/std/primitive.slice.html#method.into_vec)
#[cfg(feature = "alloc")]
#[inline]
fn into_vec(self) -> alloc::vec::Vec<Self::Item> {
self.into_boxed_slice().into_vec()
}
/// Create array from slice. Return `Err(())` if `slice.len != Self::SIZE`.
///
/// ## Examples
/// ```
/// use arraylib::ArrayExt;
///
/// let slice = &[1, 2, 3];
/// let arr = <[i32; 3]>::from_slice(slice);
/// assert_eq!(arr, Ok([1, 2, 3]));
/// ```
///
/// ```
/// # use arraylib::{ArrayExt, SizeError};
/// let slice = &[1, 2, 3, 4];
/// let arr = <[i32; 2]>::from_slice(slice);
/// // ^^^^^^ ---- wrong size, slice len = 4, arr len = 2
/// assert_eq!(arr, Err(SizeError::Greater(2, ())));
/// ```
#[inline]
fn from_slice(slice: &[Self::Item]) -> Result<Self, SizeError>
where
Self::Item: Copy,
{
SizeError::expect_size(slice, Self::SIZE, ())?;
Ok(Self::from_iter(slice.iter().copied()).unwrap())
}
/// Create array from slice. Return `Err(())` if `slice.len != Self::SIZE`.
///
/// Same as [`from_slice`](crate::ArrayExt::from_slice), but doesn't require
/// items to be `Copy`, instead only require elements to be `Clone`
///
/// ## Examples
///
/// ```
/// use arraylib::ArrayExt;
///
/// let slice = &[String::from("hi"), 123.to_string(), String::new()];
/// let arr = <[String; 3]>::clone_from_slice(slice);
/// assert_eq!(
/// arr,
/// Ok([String::from("hi"), 123.to_string(), String::new()])
/// );
/// ```
#[inline]
fn clone_from_slice(slice: &[Self::Item]) -> Result<Self, SizeError>
where
Self::Item: Clone,
{
SizeError::expect_size(slice, Self::SIZE, ())?;
Ok(Self::from_iter(slice.iter().cloned()).unwrap())
}
/// Wrap `self` into [`ArrayWrapper`](crate::ArrayWrapper)
#[inline]
fn wrap(self) -> ArrayWrapper<Self> {
ArrayWrapper::new(self)
}
}
impl<A> ArrayExt for A where A: Array {}