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cc61c64b | 1 | // Copyright 2012-2017 The Rust Project Developers. See the COPYRIGHT |
1a4d82fc JJ |
2 | // file at the top-level directory of this distribution and at |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | //! Slice management and manipulation | |
12 | //! | |
cc61c64b XL |
13 | //! For more details see [`std::slice`]. |
14 | //! | |
15 | //! [`std::slice`]: ../../std/slice/index.html | |
1a4d82fc | 16 | |
85aaf69f | 17 | #![stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
18 | |
19 | // How this module is organized. | |
20 | // | |
21 | // The library infrastructure for slices is fairly messy. There's | |
22 | // a lot of stuff defined here. Let's keep it clean. | |
23 | // | |
24 | // Since slices don't support inherent methods; all operations | |
25 | // on them are defined on traits, which are then reexported from | |
26 | // the prelude for convenience. So there are a lot of traits here. | |
27 | // | |
28 | // The layout of this file is thus: | |
29 | // | |
30 | // * Slice-specific 'extension' traits and their implementations. This | |
31 | // is where most of the slice API resides. | |
32 | // * Implementations of a few common traits with important slice ops. | |
33 | // * Definitions of a bunch of iterators. | |
34 | // * Free functions. | |
35 | // * The `raw` and `bytes` submodules. | |
36 | // * Boilerplate trait implementations. | |
37 | ||
32a655c1 | 38 | use borrow::Borrow; |
9e0c209e | 39 | use cmp::Ordering::{self, Less, Equal, Greater}; |
1a4d82fc | 40 | use cmp; |
54a0048b | 41 | use fmt; |
c34b1796 | 42 | use intrinsics::assume; |
1a4d82fc | 43 | use iter::*; |
476ff2be SL |
44 | use ops::{FnMut, self}; |
45 | use option::Option; | |
46 | use option::Option::{None, Some}; | |
47 | use result::Result; | |
48 | use result::Result::{Ok, Err}; | |
1a4d82fc | 49 | use ptr; |
1a4d82fc | 50 | use mem; |
476ff2be | 51 | use marker::{Copy, Send, Sync, Sized, self}; |
3157f602 | 52 | use iter_private::TrustedRandomAccess; |
1a4d82fc | 53 | |
7cac9316 | 54 | mod rotate; |
cc61c64b XL |
55 | mod sort; |
56 | ||
54a0048b SL |
57 | #[repr(C)] |
58 | struct Repr<T> { | |
59 | pub data: *const T, | |
60 | pub len: usize, | |
61 | } | |
1a4d82fc JJ |
62 | |
63 | // | |
64 | // Extension traits | |
65 | // | |
66 | ||
67 | /// Extension methods for slices. | |
62682a34 | 68 | #[unstable(feature = "core_slice_ext", |
e9174d1e | 69 | reason = "stable interface provided by `impl [T]` in later crates", |
54a0048b | 70 | issue = "32110")] |
92a42be0 | 71 | #[allow(missing_docs)] // documented elsewhere |
1a4d82fc JJ |
72 | pub trait SliceExt { |
73 | type Item; | |
74 | ||
92a42be0 | 75 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 76 | fn split_at(&self, mid: usize) -> (&[Self::Item], &[Self::Item]); |
cc61c64b | 77 | |
92a42be0 | 78 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 79 | fn iter(&self) -> Iter<Self::Item>; |
cc61c64b | 80 | |
92a42be0 | 81 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 82 | fn split<P>(&self, pred: P) -> Split<Self::Item, P> |
cc61c64b XL |
83 | where P: FnMut(&Self::Item) -> bool; |
84 | ||
85 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
86 | fn rsplit<P>(&self, pred: P) -> RSplit<Self::Item, P> | |
87 | where P: FnMut(&Self::Item) -> bool; | |
88 | ||
92a42be0 | 89 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 90 | fn splitn<P>(&self, n: usize, pred: P) -> SplitN<Self::Item, P> |
cc61c64b XL |
91 | where P: FnMut(&Self::Item) -> bool; |
92 | ||
92a42be0 | 93 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 94 | fn rsplitn<P>(&self, n: usize, pred: P) -> RSplitN<Self::Item, P> |
cc61c64b XL |
95 | where P: FnMut(&Self::Item) -> bool; |
96 | ||
92a42be0 | 97 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 98 | fn windows(&self, size: usize) -> Windows<Self::Item>; |
cc61c64b | 99 | |
92a42be0 | 100 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 101 | fn chunks(&self, size: usize) -> Chunks<Self::Item>; |
cc61c64b | 102 | |
92a42be0 | 103 | #[stable(feature = "core", since = "1.6.0")] |
476ff2be | 104 | fn get<I>(&self, index: I) -> Option<&I::Output> |
cc61c64b | 105 | where I: SliceIndex<Self>; |
92a42be0 | 106 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 107 | fn first(&self) -> Option<&Self::Item>; |
cc61c64b | 108 | |
92a42be0 | 109 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 110 | fn split_first(&self) -> Option<(&Self::Item, &[Self::Item])>; |
cc61c64b | 111 | |
92a42be0 | 112 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 113 | fn split_last(&self) -> Option<(&Self::Item, &[Self::Item])>; |
cc61c64b | 114 | |
92a42be0 | 115 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 116 | fn last(&self) -> Option<&Self::Item>; |
cc61c64b | 117 | |
92a42be0 | 118 | #[stable(feature = "core", since = "1.6.0")] |
476ff2be | 119 | unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output |
cc61c64b | 120 | where I: SliceIndex<Self>; |
92a42be0 | 121 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc | 122 | fn as_ptr(&self) -> *const Self::Item; |
cc61c64b | 123 | |
92a42be0 | 124 | #[stable(feature = "core", since = "1.6.0")] |
32a655c1 SL |
125 | fn binary_search<Q: ?Sized>(&self, x: &Q) -> Result<usize, usize> |
126 | where Self::Item: Borrow<Q>, | |
127 | Q: Ord; | |
cc61c64b | 128 | |
92a42be0 | 129 | #[stable(feature = "core", since = "1.6.0")] |
5bcae85e SL |
130 | fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> |
131 | where F: FnMut(&'a Self::Item) -> Ordering; | |
cc61c64b | 132 | |
a7813a04 | 133 | #[stable(feature = "slice_binary_search_by_key", since = "1.10.0")] |
32a655c1 | 134 | fn binary_search_by_key<'a, B, F, Q: ?Sized>(&'a self, b: &Q, f: F) -> Result<usize, usize> |
5bcae85e | 135 | where F: FnMut(&'a Self::Item) -> B, |
32a655c1 SL |
136 | B: Borrow<Q>, |
137 | Q: Ord; | |
cc61c64b | 138 | |
92a42be0 | 139 | #[stable(feature = "core", since = "1.6.0")] |
85aaf69f | 140 | fn len(&self) -> usize; |
cc61c64b | 141 | |
92a42be0 | 142 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc | 143 | fn is_empty(&self) -> bool { self.len() == 0 } |
cc61c64b | 144 | |
92a42be0 | 145 | #[stable(feature = "core", since = "1.6.0")] |
476ff2be | 146 | fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output> |
cc61c64b | 147 | where I: SliceIndex<Self>; |
92a42be0 | 148 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 149 | fn iter_mut(&mut self) -> IterMut<Self::Item>; |
cc61c64b | 150 | |
92a42be0 | 151 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 152 | fn first_mut(&mut self) -> Option<&mut Self::Item>; |
cc61c64b | 153 | |
92a42be0 | 154 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 155 | fn split_first_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>; |
cc61c64b | 156 | |
92a42be0 | 157 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 158 | fn split_last_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>; |
cc61c64b | 159 | |
92a42be0 | 160 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 161 | fn last_mut(&mut self) -> Option<&mut Self::Item>; |
cc61c64b | 162 | |
92a42be0 | 163 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 164 | fn split_mut<P>(&mut self, pred: P) -> SplitMut<Self::Item, P> |
cc61c64b XL |
165 | where P: FnMut(&Self::Item) -> bool; |
166 | ||
167 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
168 | fn rsplit_mut<P>(&mut self, pred: P) -> RSplitMut<Self::Item, P> | |
169 | where P: FnMut(&Self::Item) -> bool; | |
170 | ||
92a42be0 | 171 | #[stable(feature = "core", since = "1.6.0")] |
85aaf69f | 172 | fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<Self::Item, P> |
cc61c64b XL |
173 | where P: FnMut(&Self::Item) -> bool; |
174 | ||
92a42be0 | 175 | #[stable(feature = "core", since = "1.6.0")] |
85aaf69f | 176 | fn rsplitn_mut<P>(&mut self, n: usize, pred: P) -> RSplitNMut<Self::Item, P> |
cc61c64b XL |
177 | where P: FnMut(&Self::Item) -> bool; |
178 | ||
92a42be0 | 179 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 180 | fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<Self::Item>; |
cc61c64b | 181 | |
92a42be0 | 182 | #[stable(feature = "core", since = "1.6.0")] |
85aaf69f | 183 | fn swap(&mut self, a: usize, b: usize); |
cc61c64b | 184 | |
92a42be0 | 185 | #[stable(feature = "core", since = "1.6.0")] |
e9174d1e | 186 | fn split_at_mut(&mut self, mid: usize) -> (&mut [Self::Item], &mut [Self::Item]); |
cc61c64b | 187 | |
92a42be0 | 188 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc | 189 | fn reverse(&mut self); |
cc61c64b | 190 | |
92a42be0 | 191 | #[stable(feature = "core", since = "1.6.0")] |
476ff2be | 192 | unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output |
cc61c64b | 193 | where I: SliceIndex<Self>; |
92a42be0 | 194 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc JJ |
195 | fn as_mut_ptr(&mut self) -> *mut Self::Item; |
196 | ||
92a42be0 | 197 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc JJ |
198 | fn contains(&self, x: &Self::Item) -> bool where Self::Item: PartialEq; |
199 | ||
92a42be0 | 200 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc JJ |
201 | fn starts_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq; |
202 | ||
92a42be0 | 203 | #[stable(feature = "core", since = "1.6.0")] |
1a4d82fc JJ |
204 | fn ends_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq; |
205 | ||
7cac9316 XL |
206 | #[unstable(feature = "slice_rotate", issue = "41891")] |
207 | fn rotate(&mut self, mid: usize); | |
208 | ||
9cc50fc6 | 209 | #[stable(feature = "clone_from_slice", since = "1.7.0")] |
54a0048b | 210 | fn clone_from_slice(&mut self, src: &[Self::Item]) where Self::Item: Clone; |
cc61c64b | 211 | |
54a0048b | 212 | #[stable(feature = "copy_from_slice", since = "1.9.0")] |
7453a54e | 213 | fn copy_from_slice(&mut self, src: &[Self::Item]) where Self::Item: Copy; |
cc61c64b XL |
214 | |
215 | #[unstable(feature = "sort_unstable", issue = "40585")] | |
216 | fn sort_unstable(&mut self) | |
217 | where Self::Item: Ord; | |
218 | ||
219 | #[unstable(feature = "sort_unstable", issue = "40585")] | |
220 | fn sort_unstable_by<F>(&mut self, compare: F) | |
221 | where F: FnMut(&Self::Item, &Self::Item) -> Ordering; | |
222 | ||
223 | #[unstable(feature = "sort_unstable", issue = "40585")] | |
224 | fn sort_unstable_by_key<B, F>(&mut self, f: F) | |
225 | where F: FnMut(&Self::Item) -> B, | |
226 | B: Ord; | |
1a4d82fc JJ |
227 | } |
228 | ||
62682a34 SL |
229 | // Use macros to be generic over const/mut |
230 | macro_rules! slice_offset { | |
231 | ($ptr:expr, $by:expr) => {{ | |
232 | let ptr = $ptr; | |
233 | if size_from_ptr(ptr) == 0 { | |
32a655c1 | 234 | (ptr as *mut i8).wrapping_offset($by) as _ |
62682a34 SL |
235 | } else { |
236 | ptr.offset($by) | |
237 | } | |
238 | }}; | |
239 | } | |
240 | ||
32a655c1 SL |
241 | // make a &T from a *const T |
242 | macro_rules! make_ref { | |
243 | ($ptr:expr) => {{ | |
244 | let ptr = $ptr; | |
245 | if size_from_ptr(ptr) == 0 { | |
246 | // Use a non-null pointer value | |
247 | &*(1 as *mut _) | |
248 | } else { | |
249 | &*ptr | |
250 | } | |
251 | }}; | |
252 | } | |
253 | ||
254 | // make a &mut T from a *mut T | |
255 | macro_rules! make_ref_mut { | |
62682a34 SL |
256 | ($ptr:expr) => {{ |
257 | let ptr = $ptr; | |
258 | if size_from_ptr(ptr) == 0 { | |
259 | // Use a non-null pointer value | |
260 | &mut *(1 as *mut _) | |
261 | } else { | |
32a655c1 | 262 | &mut *ptr |
62682a34 SL |
263 | } |
264 | }}; | |
265 | } | |
266 | ||
92a42be0 SL |
267 | #[unstable(feature = "core_slice_ext", |
268 | reason = "stable interface provided by `impl [T]` in later crates", | |
54a0048b | 269 | issue = "32110")] |
1a4d82fc JJ |
270 | impl<T> SliceExt for [T] { |
271 | type Item = T; | |
272 | ||
273 | #[inline] | |
85aaf69f SL |
274 | fn split_at(&self, mid: usize) -> (&[T], &[T]) { |
275 | (&self[..mid], &self[mid..]) | |
1a4d82fc JJ |
276 | } |
277 | ||
278 | #[inline] | |
e9174d1e | 279 | fn iter(&self) -> Iter<T> { |
1a4d82fc | 280 | unsafe { |
62682a34 SL |
281 | let p = if mem::size_of::<T>() == 0 { |
282 | 1 as *const _ | |
1a4d82fc | 283 | } else { |
62682a34 SL |
284 | let p = self.as_ptr(); |
285 | assume(!p.is_null()); | |
286 | p | |
287 | }; | |
288 | ||
289 | Iter { | |
290 | ptr: p, | |
291 | end: slice_offset!(p, self.len() as isize), | |
292 | _marker: marker::PhantomData | |
1a4d82fc JJ |
293 | } |
294 | } | |
295 | } | |
296 | ||
297 | #[inline] | |
cc61c64b XL |
298 | fn split<P>(&self, pred: P) -> Split<T, P> |
299 | where P: FnMut(&T) -> bool | |
300 | { | |
1a4d82fc JJ |
301 | Split { |
302 | v: self, | |
303 | pred: pred, | |
304 | finished: false | |
305 | } | |
306 | } | |
307 | ||
308 | #[inline] | |
cc61c64b XL |
309 | fn rsplit<P>(&self, pred: P) -> RSplit<T, P> |
310 | where P: FnMut(&T) -> bool | |
311 | { | |
312 | RSplit { inner: self.split(pred) } | |
313 | } | |
314 | ||
315 | #[inline] | |
316 | fn splitn<P>(&self, n: usize, pred: P) -> SplitN<T, P> | |
317 | where P: FnMut(&T) -> bool | |
1a4d82fc JJ |
318 | { |
319 | SplitN { | |
320 | inner: GenericSplitN { | |
321 | iter: self.split(pred), | |
cc61c64b | 322 | count: n |
1a4d82fc JJ |
323 | } |
324 | } | |
325 | } | |
326 | ||
327 | #[inline] | |
cc61c64b XL |
328 | fn rsplitn<P>(&self, n: usize, pred: P) -> RSplitN<T, P> |
329 | where P: FnMut(&T) -> bool | |
1a4d82fc JJ |
330 | { |
331 | RSplitN { | |
332 | inner: GenericSplitN { | |
cc61c64b XL |
333 | iter: self.rsplit(pred), |
334 | count: n | |
1a4d82fc JJ |
335 | } |
336 | } | |
337 | } | |
338 | ||
339 | #[inline] | |
85aaf69f | 340 | fn windows(&self, size: usize) -> Windows<T> { |
1a4d82fc JJ |
341 | assert!(size != 0); |
342 | Windows { v: self, size: size } | |
343 | } | |
344 | ||
345 | #[inline] | |
85aaf69f | 346 | fn chunks(&self, size: usize) -> Chunks<T> { |
1a4d82fc JJ |
347 | assert!(size != 0); |
348 | Chunks { v: self, size: size } | |
349 | } | |
350 | ||
351 | #[inline] | |
476ff2be | 352 | fn get<I>(&self, index: I) -> Option<&I::Output> |
cc61c64b | 353 | where I: SliceIndex<[T]> |
476ff2be SL |
354 | { |
355 | index.get(self) | |
1a4d82fc JJ |
356 | } |
357 | ||
358 | #[inline] | |
359 | fn first(&self) -> Option<&T> { | |
9346a6ac | 360 | if self.is_empty() { None } else { Some(&self[0]) } |
1a4d82fc JJ |
361 | } |
362 | ||
1a4d82fc | 363 | #[inline] |
c1a9b12d SL |
364 | fn split_first(&self) -> Option<(&T, &[T])> { |
365 | if self.is_empty() { None } else { Some((&self[0], &self[1..])) } | |
366 | } | |
367 | ||
c1a9b12d SL |
368 | #[inline] |
369 | fn split_last(&self) -> Option<(&T, &[T])> { | |
370 | let len = self.len(); | |
371 | if len == 0 { None } else { Some((&self[len - 1], &self[..(len - 1)])) } | |
1a4d82fc JJ |
372 | } |
373 | ||
374 | #[inline] | |
375 | fn last(&self) -> Option<&T> { | |
9346a6ac | 376 | if self.is_empty() { None } else { Some(&self[self.len() - 1]) } |
1a4d82fc JJ |
377 | } |
378 | ||
379 | #[inline] | |
476ff2be | 380 | unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output |
cc61c64b | 381 | where I: SliceIndex<[T]> |
476ff2be SL |
382 | { |
383 | index.get_unchecked(self) | |
1a4d82fc JJ |
384 | } |
385 | ||
386 | #[inline] | |
387 | fn as_ptr(&self) -> *const T { | |
54a0048b | 388 | self as *const [T] as *const T |
1a4d82fc JJ |
389 | } |
390 | ||
5bcae85e SL |
391 | fn binary_search_by<'a, F>(&'a self, mut f: F) -> Result<usize, usize> |
392 | where F: FnMut(&'a T) -> Ordering | |
1a4d82fc | 393 | { |
7453a54e SL |
394 | let mut base = 0usize; |
395 | let mut s = self; | |
1a4d82fc | 396 | |
7453a54e SL |
397 | loop { |
398 | let (head, tail) = s.split_at(s.len() >> 1); | |
399 | if tail.is_empty() { | |
400 | return Err(base) | |
401 | } | |
402 | match f(&tail[0]) { | |
1a4d82fc | 403 | Less => { |
7453a54e SL |
404 | base += head.len() + 1; |
405 | s = &tail[1..]; | |
1a4d82fc | 406 | } |
7453a54e SL |
407 | Greater => s = head, |
408 | Equal => return Ok(base + head.len()), | |
1a4d82fc | 409 | } |
1a4d82fc | 410 | } |
1a4d82fc JJ |
411 | } |
412 | ||
413 | #[inline] | |
54a0048b SL |
414 | fn len(&self) -> usize { |
415 | unsafe { | |
416 | mem::transmute::<&[T], Repr<T>>(self).len | |
417 | } | |
418 | } | |
1a4d82fc JJ |
419 | |
420 | #[inline] | |
476ff2be | 421 | fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output> |
cc61c64b | 422 | where I: SliceIndex<[T]> |
476ff2be SL |
423 | { |
424 | index.get_mut(self) | |
1a4d82fc JJ |
425 | } |
426 | ||
1a4d82fc | 427 | #[inline] |
85aaf69f | 428 | fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T]) { |
c1a9b12d SL |
429 | let len = self.len(); |
430 | let ptr = self.as_mut_ptr(); | |
e9174d1e | 431 | |
1a4d82fc | 432 | unsafe { |
e9174d1e SL |
433 | assert!(mid <= len); |
434 | ||
c1a9b12d SL |
435 | (from_raw_parts_mut(ptr, mid), |
436 | from_raw_parts_mut(ptr.offset(mid as isize), len - mid)) | |
1a4d82fc JJ |
437 | } |
438 | } | |
439 | ||
440 | #[inline] | |
e9174d1e | 441 | fn iter_mut(&mut self) -> IterMut<T> { |
1a4d82fc | 442 | unsafe { |
62682a34 SL |
443 | let p = if mem::size_of::<T>() == 0 { |
444 | 1 as *mut _ | |
1a4d82fc | 445 | } else { |
62682a34 SL |
446 | let p = self.as_mut_ptr(); |
447 | assume(!p.is_null()); | |
448 | p | |
449 | }; | |
450 | ||
451 | IterMut { | |
452 | ptr: p, | |
453 | end: slice_offset!(p, self.len() as isize), | |
454 | _marker: marker::PhantomData | |
1a4d82fc JJ |
455 | } |
456 | } | |
457 | } | |
458 | ||
459 | #[inline] | |
460 | fn last_mut(&mut self) -> Option<&mut T> { | |
461 | let len = self.len(); | |
462 | if len == 0 { return None; } | |
463 | Some(&mut self[len - 1]) | |
464 | } | |
465 | ||
466 | #[inline] | |
467 | fn first_mut(&mut self) -> Option<&mut T> { | |
9346a6ac | 468 | if self.is_empty() { None } else { Some(&mut self[0]) } |
1a4d82fc JJ |
469 | } |
470 | ||
c1a9b12d SL |
471 | #[inline] |
472 | fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])> { | |
473 | if self.is_empty() { None } else { | |
474 | let split = self.split_at_mut(1); | |
475 | Some((&mut split.0[0], split.1)) | |
476 | } | |
1a4d82fc JJ |
477 | } |
478 | ||
c1a9b12d SL |
479 | #[inline] |
480 | fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])> { | |
481 | let len = self.len(); | |
482 | if len == 0 { None } else { | |
483 | let split = self.split_at_mut(len - 1); | |
484 | Some((&mut split.1[0], split.0)) | |
485 | } | |
486 | } | |
487 | ||
1a4d82fc | 488 | #[inline] |
cc61c64b XL |
489 | fn split_mut<P>(&mut self, pred: P) -> SplitMut<T, P> |
490 | where P: FnMut(&T) -> bool | |
491 | { | |
1a4d82fc JJ |
492 | SplitMut { v: self, pred: pred, finished: false } |
493 | } | |
494 | ||
495 | #[inline] | |
cc61c64b XL |
496 | fn rsplit_mut<P>(&mut self, pred: P) -> RSplitMut<T, P> |
497 | where P: FnMut(&T) -> bool | |
498 | { | |
499 | RSplitMut { inner: self.split_mut(pred) } | |
500 | } | |
501 | ||
502 | #[inline] | |
503 | fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<T, P> | |
504 | where P: FnMut(&T) -> bool | |
1a4d82fc JJ |
505 | { |
506 | SplitNMut { | |
507 | inner: GenericSplitN { | |
508 | iter: self.split_mut(pred), | |
cc61c64b | 509 | count: n |
1a4d82fc JJ |
510 | } |
511 | } | |
512 | } | |
513 | ||
514 | #[inline] | |
e9174d1e | 515 | fn rsplitn_mut<P>(&mut self, n: usize, pred: P) -> RSplitNMut<T, P> where |
1a4d82fc JJ |
516 | P: FnMut(&T) -> bool, |
517 | { | |
518 | RSplitNMut { | |
519 | inner: GenericSplitN { | |
cc61c64b XL |
520 | iter: self.rsplit_mut(pred), |
521 | count: n | |
1a4d82fc JJ |
522 | } |
523 | } | |
cc61c64b | 524 | } |
1a4d82fc JJ |
525 | |
526 | #[inline] | |
85aaf69f | 527 | fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<T> { |
1a4d82fc JJ |
528 | assert!(chunk_size > 0); |
529 | ChunksMut { v: self, chunk_size: chunk_size } | |
530 | } | |
531 | ||
c34b1796 | 532 | #[inline] |
85aaf69f | 533 | fn swap(&mut self, a: usize, b: usize) { |
1a4d82fc JJ |
534 | unsafe { |
535 | // Can't take two mutable loans from one vector, so instead just cast | |
536 | // them to their raw pointers to do the swap | |
537 | let pa: *mut T = &mut self[a]; | |
538 | let pb: *mut T = &mut self[b]; | |
539 | ptr::swap(pa, pb); | |
540 | } | |
541 | } | |
542 | ||
543 | fn reverse(&mut self) { | |
85aaf69f | 544 | let mut i: usize = 0; |
1a4d82fc | 545 | let ln = self.len(); |
7cac9316 XL |
546 | |
547 | // For very small types, all the individual reads in the normal | |
548 | // path perform poorly. We can do better, given efficient unaligned | |
549 | // load/store, by loading a larger chunk and reversing a register. | |
550 | ||
551 | // Ideally LLVM would do this for us, as it knows better than we do | |
552 | // whether unaligned reads are efficient (since that changes between | |
553 | // different ARM versions, for example) and what the best chunk size | |
554 | // would be. Unfortunately, as of LLVM 4.0 (2017-05) it only unrolls | |
555 | // the loop, so we need to do this ourselves. (Hypothesis: reverse | |
556 | // is troublesome because the sides can be aligned differently -- | |
557 | // will be, when the length is odd -- so there's no way of emitting | |
558 | // pre- and postludes to use fully-aligned SIMD in the middle.) | |
559 | ||
560 | let fast_unaligned = | |
561 | cfg!(any(target_arch = "x86", target_arch = "x86_64")); | |
562 | ||
563 | if fast_unaligned && mem::size_of::<T>() == 1 { | |
564 | // Use the llvm.bswap intrinsic to reverse u8s in a usize | |
565 | let chunk = mem::size_of::<usize>(); | |
566 | while i + chunk - 1 < ln / 2 { | |
567 | unsafe { | |
568 | let pa: *mut T = self.get_unchecked_mut(i); | |
569 | let pb: *mut T = self.get_unchecked_mut(ln - i - chunk); | |
570 | let va = ptr::read_unaligned(pa as *mut usize); | |
571 | let vb = ptr::read_unaligned(pb as *mut usize); | |
572 | ptr::write_unaligned(pa as *mut usize, vb.swap_bytes()); | |
573 | ptr::write_unaligned(pb as *mut usize, va.swap_bytes()); | |
574 | } | |
575 | i += chunk; | |
576 | } | |
577 | } | |
578 | ||
579 | if fast_unaligned && mem::size_of::<T>() == 2 { | |
580 | // Use rotate-by-16 to reverse u16s in a u32 | |
581 | let chunk = mem::size_of::<u32>() / 2; | |
582 | while i + chunk - 1 < ln / 2 { | |
583 | unsafe { | |
584 | let pa: *mut T = self.get_unchecked_mut(i); | |
585 | let pb: *mut T = self.get_unchecked_mut(ln - i - chunk); | |
586 | let va = ptr::read_unaligned(pa as *mut u32); | |
587 | let vb = ptr::read_unaligned(pb as *mut u32); | |
588 | ptr::write_unaligned(pa as *mut u32, vb.rotate_left(16)); | |
589 | ptr::write_unaligned(pb as *mut u32, va.rotate_left(16)); | |
590 | } | |
591 | i += chunk; | |
592 | } | |
593 | } | |
594 | ||
1a4d82fc JJ |
595 | while i < ln / 2 { |
596 | // Unsafe swap to avoid the bounds check in safe swap. | |
597 | unsafe { | |
598 | let pa: *mut T = self.get_unchecked_mut(i); | |
599 | let pb: *mut T = self.get_unchecked_mut(ln - i - 1); | |
600 | ptr::swap(pa, pb); | |
601 | } | |
602 | i += 1; | |
603 | } | |
604 | } | |
605 | ||
606 | #[inline] | |
476ff2be | 607 | unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output |
cc61c64b | 608 | where I: SliceIndex<[T]> |
476ff2be SL |
609 | { |
610 | index.get_unchecked_mut(self) | |
1a4d82fc JJ |
611 | } |
612 | ||
613 | #[inline] | |
614 | fn as_mut_ptr(&mut self) -> *mut T { | |
54a0048b | 615 | self as *mut [T] as *mut T |
1a4d82fc JJ |
616 | } |
617 | ||
1a4d82fc JJ |
618 | #[inline] |
619 | fn contains(&self, x: &T) -> bool where T: PartialEq { | |
620 | self.iter().any(|elt| *x == *elt) | |
621 | } | |
622 | ||
623 | #[inline] | |
624 | fn starts_with(&self, needle: &[T]) -> bool where T: PartialEq { | |
625 | let n = needle.len(); | |
85aaf69f | 626 | self.len() >= n && needle == &self[..n] |
1a4d82fc JJ |
627 | } |
628 | ||
629 | #[inline] | |
630 | fn ends_with(&self, needle: &[T]) -> bool where T: PartialEq { | |
631 | let (m, n) = (self.len(), needle.len()); | |
85aaf69f | 632 | m >= n && needle == &self[m-n..] |
1a4d82fc JJ |
633 | } |
634 | ||
cc61c64b XL |
635 | fn binary_search<Q: ?Sized>(&self, x: &Q) -> Result<usize, usize> |
636 | where T: Borrow<Q>, | |
637 | Q: Ord | |
638 | { | |
32a655c1 | 639 | self.binary_search_by(|p| p.borrow().cmp(x)) |
1a4d82fc JJ |
640 | } |
641 | ||
7cac9316 XL |
642 | fn rotate(&mut self, mid: usize) { |
643 | assert!(mid <= self.len()); | |
644 | let k = self.len() - mid; | |
645 | ||
646 | unsafe { | |
647 | let p = self.as_mut_ptr(); | |
648 | rotate::ptr_rotate(mid, p.offset(mid as isize), k); | |
649 | } | |
650 | } | |
651 | ||
1a4d82fc | 652 | #[inline] |
9cc50fc6 SL |
653 | fn clone_from_slice(&mut self, src: &[T]) where T: Clone { |
654 | assert!(self.len() == src.len(), | |
655 | "destination and source slices have different lengths"); | |
656 | // NOTE: We need to explicitly slice them to the same length | |
657 | // for bounds checking to be elided, and the optimizer will | |
658 | // generate memcpy for simple cases (for example T = u8). | |
659 | let len = self.len(); | |
660 | let src = &src[..len]; | |
661 | for i in 0..len { | |
662 | self[i].clone_from(&src[i]); | |
1a4d82fc | 663 | } |
1a4d82fc | 664 | } |
7453a54e SL |
665 | |
666 | #[inline] | |
667 | fn copy_from_slice(&mut self, src: &[T]) where T: Copy { | |
668 | assert!(self.len() == src.len(), | |
669 | "destination and source slices have different lengths"); | |
670 | unsafe { | |
671 | ptr::copy_nonoverlapping( | |
672 | src.as_ptr(), self.as_mut_ptr(), self.len()); | |
673 | } | |
674 | } | |
a7813a04 XL |
675 | |
676 | #[inline] | |
32a655c1 | 677 | fn binary_search_by_key<'a, B, F, Q: ?Sized>(&'a self, b: &Q, mut f: F) -> Result<usize, usize> |
5bcae85e | 678 | where F: FnMut(&'a Self::Item) -> B, |
32a655c1 SL |
679 | B: Borrow<Q>, |
680 | Q: Ord | |
a7813a04 | 681 | { |
32a655c1 | 682 | self.binary_search_by(|k| f(k).borrow().cmp(b)) |
a7813a04 | 683 | } |
cc61c64b XL |
684 | |
685 | #[inline] | |
686 | fn sort_unstable(&mut self) | |
687 | where Self::Item: Ord | |
688 | { | |
689 | sort::quicksort(self, |a, b| a.lt(b)); | |
690 | } | |
691 | ||
692 | #[inline] | |
693 | fn sort_unstable_by<F>(&mut self, mut compare: F) | |
694 | where F: FnMut(&Self::Item, &Self::Item) -> Ordering | |
695 | { | |
696 | sort::quicksort(self, |a, b| compare(a, b) == Ordering::Less); | |
697 | } | |
698 | ||
699 | #[inline] | |
700 | fn sort_unstable_by_key<B, F>(&mut self, mut f: F) | |
701 | where F: FnMut(&Self::Item) -> B, | |
702 | B: Ord | |
703 | { | |
704 | sort::quicksort(self, |a, b| f(a).lt(&f(b))); | |
705 | } | |
1a4d82fc JJ |
706 | } |
707 | ||
85aaf69f | 708 | #[stable(feature = "rust1", since = "1.0.0")] |
476ff2be SL |
709 | #[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"] |
710 | impl<T, I> ops::Index<I> for [T] | |
cc61c64b | 711 | where I: SliceIndex<[T]> |
476ff2be SL |
712 | { |
713 | type Output = I::Output; | |
1a4d82fc | 714 | |
476ff2be SL |
715 | #[inline] |
716 | fn index(&self, index: I) -> &I::Output { | |
717 | index.index(self) | |
1a4d82fc JJ |
718 | } |
719 | } | |
720 | ||
85aaf69f | 721 | #[stable(feature = "rust1", since = "1.0.0")] |
476ff2be SL |
722 | #[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"] |
723 | impl<T, I> ops::IndexMut<I> for [T] | |
cc61c64b | 724 | where I: SliceIndex<[T]> |
476ff2be | 725 | { |
c34b1796 | 726 | #[inline] |
476ff2be SL |
727 | fn index_mut(&mut self, index: I) -> &mut I::Output { |
728 | index.index_mut(self) | |
1a4d82fc JJ |
729 | } |
730 | } | |
731 | ||
92a42be0 SL |
732 | #[inline(never)] |
733 | #[cold] | |
734 | fn slice_index_len_fail(index: usize, len: usize) -> ! { | |
735 | panic!("index {} out of range for slice of length {}", index, len); | |
736 | } | |
737 | ||
738 | #[inline(never)] | |
739 | #[cold] | |
740 | fn slice_index_order_fail(index: usize, end: usize) -> ! { | |
741 | panic!("slice index starts at {} but ends at {}", index, end); | |
742 | } | |
743 | ||
476ff2be SL |
744 | /// A helper trait used for indexing operations. |
745 | #[unstable(feature = "slice_get_slice", issue = "35729")] | |
746 | #[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"] | |
cc61c64b | 747 | pub trait SliceIndex<T: ?Sized> { |
476ff2be SL |
748 | /// The output type returned by methods. |
749 | type Output: ?Sized; | |
54a0048b | 750 | |
476ff2be SL |
751 | /// Returns a shared reference to the output at this location, if in |
752 | /// bounds. | |
cc61c64b | 753 | fn get(self, slice: &T) -> Option<&Self::Output>; |
476ff2be SL |
754 | |
755 | /// Returns a mutable reference to the output at this location, if in | |
756 | /// bounds. | |
cc61c64b | 757 | fn get_mut(self, slice: &mut T) -> Option<&mut Self::Output>; |
476ff2be SL |
758 | |
759 | /// Returns a shared reference to the output at this location, without | |
760 | /// performing any bounds checking. | |
cc61c64b | 761 | unsafe fn get_unchecked(self, slice: &T) -> &Self::Output; |
476ff2be SL |
762 | |
763 | /// Returns a mutable reference to the output at this location, without | |
764 | /// performing any bounds checking. | |
cc61c64b | 765 | unsafe fn get_unchecked_mut(self, slice: &mut T) -> &mut Self::Output; |
476ff2be SL |
766 | |
767 | /// Returns a shared reference to the output at this location, panicking | |
768 | /// if out of bounds. | |
cc61c64b | 769 | fn index(self, slice: &T) -> &Self::Output; |
476ff2be SL |
770 | |
771 | /// Returns a mutable reference to the output at this location, panicking | |
772 | /// if out of bounds. | |
cc61c64b | 773 | fn index_mut(self, slice: &mut T) -> &mut Self::Output; |
476ff2be SL |
774 | } |
775 | ||
8bb4bdeb | 776 | #[stable(feature = "slice-get-slice-impls", since = "1.15.0")] |
cc61c64b | 777 | impl<T> SliceIndex<[T]> for usize { |
476ff2be SL |
778 | type Output = T; |
779 | ||
780 | #[inline] | |
781 | fn get(self, slice: &[T]) -> Option<&T> { | |
782 | if self < slice.len() { | |
783 | unsafe { | |
784 | Some(self.get_unchecked(slice)) | |
785 | } | |
786 | } else { | |
787 | None | |
788 | } | |
789 | } | |
790 | ||
791 | #[inline] | |
792 | fn get_mut(self, slice: &mut [T]) -> Option<&mut T> { | |
793 | if self < slice.len() { | |
794 | unsafe { | |
795 | Some(self.get_unchecked_mut(slice)) | |
796 | } | |
797 | } else { | |
798 | None | |
799 | } | |
800 | } | |
801 | ||
802 | #[inline] | |
803 | unsafe fn get_unchecked(self, slice: &[T]) -> &T { | |
804 | &*slice.as_ptr().offset(self as isize) | |
805 | } | |
806 | ||
807 | #[inline] | |
808 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut T { | |
809 | &mut *slice.as_mut_ptr().offset(self as isize) | |
810 | } | |
811 | ||
812 | #[inline] | |
813 | fn index(self, slice: &[T]) -> &T { | |
814 | // NB: use intrinsic indexing | |
815 | &(*slice)[self] | |
816 | } | |
817 | ||
818 | #[inline] | |
819 | fn index_mut(self, slice: &mut [T]) -> &mut T { | |
820 | // NB: use intrinsic indexing | |
821 | &mut (*slice)[self] | |
822 | } | |
823 | } | |
824 | ||
8bb4bdeb | 825 | #[stable(feature = "slice-get-slice-impls", since = "1.15.0")] |
cc61c64b | 826 | impl<T> SliceIndex<[T]> for ops::Range<usize> { |
1a4d82fc | 827 | type Output = [T]; |
c34b1796 | 828 | |
1a4d82fc | 829 | #[inline] |
476ff2be SL |
830 | fn get(self, slice: &[T]) -> Option<&[T]> { |
831 | if self.start > self.end || self.end > slice.len() { | |
832 | None | |
833 | } else { | |
834 | unsafe { | |
835 | Some(self.get_unchecked(slice)) | |
836 | } | |
837 | } | |
838 | } | |
839 | ||
840 | #[inline] | |
841 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { | |
842 | if self.start > self.end || self.end > slice.len() { | |
843 | None | |
844 | } else { | |
845 | unsafe { | |
846 | Some(self.get_unchecked_mut(slice)) | |
847 | } | |
848 | } | |
849 | } | |
850 | ||
851 | #[inline] | |
852 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { | |
853 | from_raw_parts(slice.as_ptr().offset(self.start as isize), self.end - self.start) | |
854 | } | |
855 | ||
856 | #[inline] | |
857 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { | |
858 | from_raw_parts_mut(slice.as_mut_ptr().offset(self.start as isize), self.end - self.start) | |
859 | } | |
860 | ||
861 | #[inline] | |
862 | fn index(self, slice: &[T]) -> &[T] { | |
863 | if self.start > self.end { | |
864 | slice_index_order_fail(self.start, self.end); | |
865 | } else if self.end > slice.len() { | |
866 | slice_index_len_fail(self.end, slice.len()); | |
92a42be0 | 867 | } |
1a4d82fc | 868 | unsafe { |
476ff2be SL |
869 | self.get_unchecked(slice) |
870 | } | |
871 | } | |
872 | ||
873 | #[inline] | |
874 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
875 | if self.start > self.end { | |
876 | slice_index_order_fail(self.start, self.end); | |
877 | } else if self.end > slice.len() { | |
878 | slice_index_len_fail(self.end, slice.len()); | |
879 | } | |
880 | unsafe { | |
881 | self.get_unchecked_mut(slice) | |
1a4d82fc JJ |
882 | } |
883 | } | |
884 | } | |
54a0048b | 885 | |
8bb4bdeb | 886 | #[stable(feature = "slice-get-slice-impls", since = "1.15.0")] |
cc61c64b | 887 | impl<T> SliceIndex<[T]> for ops::RangeTo<usize> { |
1a4d82fc | 888 | type Output = [T]; |
c34b1796 | 889 | |
1a4d82fc | 890 | #[inline] |
476ff2be SL |
891 | fn get(self, slice: &[T]) -> Option<&[T]> { |
892 | (0..self.end).get(slice) | |
893 | } | |
894 | ||
895 | #[inline] | |
896 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { | |
897 | (0..self.end).get_mut(slice) | |
898 | } | |
899 | ||
900 | #[inline] | |
901 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { | |
902 | (0..self.end).get_unchecked(slice) | |
903 | } | |
904 | ||
905 | #[inline] | |
906 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { | |
907 | (0..self.end).get_unchecked_mut(slice) | |
908 | } | |
909 | ||
910 | #[inline] | |
911 | fn index(self, slice: &[T]) -> &[T] { | |
912 | (0..self.end).index(slice) | |
913 | } | |
914 | ||
915 | #[inline] | |
916 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
917 | (0..self.end).index_mut(slice) | |
1a4d82fc JJ |
918 | } |
919 | } | |
54a0048b | 920 | |
8bb4bdeb | 921 | #[stable(feature = "slice-get-slice-impls", since = "1.15.0")] |
cc61c64b | 922 | impl<T> SliceIndex<[T]> for ops::RangeFrom<usize> { |
1a4d82fc | 923 | type Output = [T]; |
c34b1796 | 924 | |
1a4d82fc | 925 | #[inline] |
476ff2be SL |
926 | fn get(self, slice: &[T]) -> Option<&[T]> { |
927 | (self.start..slice.len()).get(slice) | |
928 | } | |
929 | ||
930 | #[inline] | |
931 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { | |
932 | (self.start..slice.len()).get_mut(slice) | |
933 | } | |
934 | ||
935 | #[inline] | |
936 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { | |
937 | (self.start..slice.len()).get_unchecked(slice) | |
938 | } | |
939 | ||
940 | #[inline] | |
941 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { | |
942 | (self.start..slice.len()).get_unchecked_mut(slice) | |
943 | } | |
944 | ||
945 | #[inline] | |
946 | fn index(self, slice: &[T]) -> &[T] { | |
947 | (self.start..slice.len()).index(slice) | |
948 | } | |
949 | ||
950 | #[inline] | |
951 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
952 | (self.start..slice.len()).index_mut(slice) | |
1a4d82fc JJ |
953 | } |
954 | } | |
54a0048b | 955 | |
8bb4bdeb | 956 | #[stable(feature = "slice-get-slice-impls", since = "1.15.0")] |
cc61c64b | 957 | impl<T> SliceIndex<[T]> for ops::RangeFull { |
1a4d82fc | 958 | type Output = [T]; |
c34b1796 | 959 | |
1a4d82fc | 960 | #[inline] |
476ff2be SL |
961 | fn get(self, slice: &[T]) -> Option<&[T]> { |
962 | Some(slice) | |
963 | } | |
964 | ||
965 | #[inline] | |
966 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { | |
967 | Some(slice) | |
968 | } | |
969 | ||
970 | #[inline] | |
971 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { | |
972 | slice | |
973 | } | |
974 | ||
975 | #[inline] | |
976 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { | |
977 | slice | |
978 | } | |
979 | ||
980 | #[inline] | |
981 | fn index(self, slice: &[T]) -> &[T] { | |
982 | slice | |
983 | } | |
984 | ||
985 | #[inline] | |
986 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
987 | slice | |
1a4d82fc JJ |
988 | } |
989 | } | |
990 | ||
476ff2be | 991 | |
8bb4bdeb | 992 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
cc61c64b | 993 | impl<T> SliceIndex<[T]> for ops::RangeInclusive<usize> { |
54a0048b SL |
994 | type Output = [T]; |
995 | ||
996 | #[inline] | |
476ff2be | 997 | fn get(self, slice: &[T]) -> Option<&[T]> { |
7cac9316 XL |
998 | if self.end == usize::max_value() { None } |
999 | else { (self.start..self.end + 1).get(slice) } | |
476ff2be SL |
1000 | } |
1001 | ||
1002 | #[inline] | |
1003 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { | |
7cac9316 XL |
1004 | if self.end == usize::max_value() { None } |
1005 | else { (self.start..self.end + 1).get_mut(slice) } | |
476ff2be SL |
1006 | } |
1007 | ||
1008 | #[inline] | |
1009 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { | |
7cac9316 | 1010 | (self.start..self.end + 1).get_unchecked(slice) |
54a0048b | 1011 | } |
54a0048b SL |
1012 | |
1013 | #[inline] | |
476ff2be | 1014 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { |
7cac9316 | 1015 | (self.start..self.end + 1).get_unchecked_mut(slice) |
54a0048b | 1016 | } |
54a0048b | 1017 | |
476ff2be SL |
1018 | #[inline] |
1019 | fn index(self, slice: &[T]) -> &[T] { | |
7cac9316 XL |
1020 | assert!(self.end != usize::max_value(), |
1021 | "attempted to index slice up to maximum usize"); | |
1022 | (self.start..self.end + 1).index(slice) | |
476ff2be SL |
1023 | } |
1024 | ||
1025 | #[inline] | |
1026 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
7cac9316 XL |
1027 | assert!(self.end != usize::max_value(), |
1028 | "attempted to index slice up to maximum usize"); | |
1029 | (self.start..self.end + 1).index_mut(slice) | |
1a4d82fc JJ |
1030 | } |
1031 | } | |
54a0048b | 1032 | |
7cac9316 XL |
1033 | #[cfg(stage0)] // The bootstrap compiler has a different `...` desugar |
1034 | fn inclusive(start: usize, end: usize) -> ops::RangeInclusive<usize> { | |
1035 | ops::RangeInclusive { start, end } | |
1036 | } | |
1037 | #[cfg(not(stage0))] | |
1038 | fn inclusive(start: usize, end: usize) -> ops::RangeInclusive<usize> { | |
1039 | start...end | |
1040 | } | |
1041 | ||
8bb4bdeb | 1042 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
cc61c64b | 1043 | impl<T> SliceIndex<[T]> for ops::RangeToInclusive<usize> { |
476ff2be SL |
1044 | type Output = [T]; |
1045 | ||
1a4d82fc | 1046 | #[inline] |
476ff2be | 1047 | fn get(self, slice: &[T]) -> Option<&[T]> { |
7cac9316 | 1048 | inclusive(0, self.end).get(slice) |
1a4d82fc | 1049 | } |
54a0048b | 1050 | |
1a4d82fc | 1051 | #[inline] |
476ff2be | 1052 | fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> { |
7cac9316 | 1053 | inclusive(0, self.end).get_mut(slice) |
1a4d82fc | 1054 | } |
54a0048b | 1055 | |
1a4d82fc | 1056 | #[inline] |
476ff2be | 1057 | unsafe fn get_unchecked(self, slice: &[T]) -> &[T] { |
7cac9316 | 1058 | inclusive(0, self.end).get_unchecked(slice) |
1a4d82fc | 1059 | } |
1a4d82fc | 1060 | |
54a0048b | 1061 | #[inline] |
476ff2be | 1062 | unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T] { |
7cac9316 | 1063 | inclusive(0, self.end).get_unchecked_mut(slice) |
54a0048b | 1064 | } |
476ff2be | 1065 | |
54a0048b | 1066 | #[inline] |
476ff2be | 1067 | fn index(self, slice: &[T]) -> &[T] { |
7cac9316 | 1068 | inclusive(0, self.end).index(slice) |
476ff2be SL |
1069 | } |
1070 | ||
1071 | #[inline] | |
1072 | fn index_mut(self, slice: &mut [T]) -> &mut [T] { | |
7cac9316 | 1073 | inclusive(0, self.end).index_mut(slice) |
54a0048b SL |
1074 | } |
1075 | } | |
1a4d82fc JJ |
1076 | |
1077 | //////////////////////////////////////////////////////////////////////////////// | |
1078 | // Common traits | |
1079 | //////////////////////////////////////////////////////////////////////////////// | |
1080 | ||
85aaf69f | 1081 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1082 | impl<'a, T> Default for &'a [T] { |
9e0c209e | 1083 | /// Creates an empty slice. |
1a4d82fc JJ |
1084 | fn default() -> &'a [T] { &[] } |
1085 | } | |
1086 | ||
b039eaaf SL |
1087 | #[stable(feature = "mut_slice_default", since = "1.5.0")] |
1088 | impl<'a, T> Default for &'a mut [T] { | |
9e0c209e | 1089 | /// Creates a mutable empty slice. |
b039eaaf SL |
1090 | fn default() -> &'a mut [T] { &mut [] } |
1091 | } | |
1092 | ||
1a4d82fc JJ |
1093 | // |
1094 | // Iterators | |
1095 | // | |
1096 | ||
85aaf69f SL |
1097 | #[stable(feature = "rust1", since = "1.0.0")] |
1098 | impl<'a, T> IntoIterator for &'a [T] { | |
1099 | type Item = &'a T; | |
1100 | type IntoIter = Iter<'a, T>; | |
1101 | ||
1102 | fn into_iter(self) -> Iter<'a, T> { | |
1103 | self.iter() | |
1104 | } | |
1105 | } | |
1106 | ||
1107 | #[stable(feature = "rust1", since = "1.0.0")] | |
1108 | impl<'a, T> IntoIterator for &'a mut [T] { | |
1109 | type Item = &'a mut T; | |
1110 | type IntoIter = IterMut<'a, T>; | |
1111 | ||
1112 | fn into_iter(self) -> IterMut<'a, T> { | |
1113 | self.iter_mut() | |
1114 | } | |
1115 | } | |
1116 | ||
d9579d0f AL |
1117 | #[inline(always)] |
1118 | fn size_from_ptr<T>(_: *const T) -> usize { | |
1119 | mem::size_of::<T>() | |
1120 | } | |
1121 | ||
1a4d82fc JJ |
1122 | // The shared definition of the `Iter` and `IterMut` iterators |
1123 | macro_rules! iterator { | |
32a655c1 | 1124 | (struct $name:ident -> $ptr:ty, $elem:ty, $mkref:ident) => { |
85aaf69f | 1125 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1126 | impl<'a, T> Iterator for $name<'a, T> { |
1127 | type Item = $elem; | |
1128 | ||
1129 | #[inline] | |
1130 | fn next(&mut self) -> Option<$elem> { | |
1131 | // could be implemented with slices, but this avoids bounds checks | |
1132 | unsafe { | |
d9579d0f AL |
1133 | if mem::size_of::<T>() != 0 { |
1134 | assume(!self.ptr.is_null()); | |
1135 | assume(!self.end.is_null()); | |
1136 | } | |
1a4d82fc JJ |
1137 | if self.ptr == self.end { |
1138 | None | |
1139 | } else { | |
32a655c1 | 1140 | Some($mkref!(self.ptr.post_inc())) |
1a4d82fc JJ |
1141 | } |
1142 | } | |
1143 | } | |
1144 | ||
1145 | #[inline] | |
85aaf69f | 1146 | fn size_hint(&self) -> (usize, Option<usize>) { |
32a655c1 | 1147 | let exact = ptrdistance(self.ptr, self.end); |
1a4d82fc JJ |
1148 | (exact, Some(exact)) |
1149 | } | |
d9579d0f AL |
1150 | |
1151 | #[inline] | |
1152 | fn count(self) -> usize { | |
3157f602 | 1153 | self.len() |
d9579d0f AL |
1154 | } |
1155 | ||
1156 | #[inline] | |
1157 | fn nth(&mut self, n: usize) -> Option<$elem> { | |
1158 | // Call helper method. Can't put the definition here because mut versus const. | |
1159 | self.iter_nth(n) | |
1160 | } | |
1161 | ||
1162 | #[inline] | |
1163 | fn last(mut self) -> Option<$elem> { | |
1164 | self.next_back() | |
1165 | } | |
32a655c1 SL |
1166 | |
1167 | fn all<F>(&mut self, mut predicate: F) -> bool | |
1168 | where F: FnMut(Self::Item) -> bool, | |
1169 | { | |
1170 | self.search_while(true, move |elt| { | |
1171 | if predicate(elt) { | |
1172 | SearchWhile::Continue | |
1173 | } else { | |
1174 | SearchWhile::Done(false) | |
1175 | } | |
1176 | }) | |
1177 | } | |
1178 | ||
1179 | fn any<F>(&mut self, mut predicate: F) -> bool | |
1180 | where F: FnMut(Self::Item) -> bool, | |
1181 | { | |
1182 | !self.all(move |elt| !predicate(elt)) | |
1183 | } | |
1184 | ||
1185 | fn find<F>(&mut self, mut predicate: F) -> Option<Self::Item> | |
1186 | where F: FnMut(&Self::Item) -> bool, | |
1187 | { | |
1188 | self.search_while(None, move |elt| { | |
1189 | if predicate(&elt) { | |
1190 | SearchWhile::Done(Some(elt)) | |
1191 | } else { | |
1192 | SearchWhile::Continue | |
1193 | } | |
1194 | }) | |
1195 | } | |
1196 | ||
1197 | fn position<F>(&mut self, mut predicate: F) -> Option<usize> | |
1198 | where F: FnMut(Self::Item) -> bool, | |
1199 | { | |
1200 | let mut index = 0; | |
1201 | self.search_while(None, move |elt| { | |
1202 | if predicate(elt) { | |
1203 | SearchWhile::Done(Some(index)) | |
1204 | } else { | |
1205 | index += 1; | |
1206 | SearchWhile::Continue | |
1207 | } | |
1208 | }) | |
1209 | } | |
1210 | ||
1211 | fn rposition<F>(&mut self, mut predicate: F) -> Option<usize> | |
1212 | where F: FnMut(Self::Item) -> bool, | |
1213 | { | |
1214 | let mut index = self.len(); | |
1215 | self.rsearch_while(None, move |elt| { | |
1216 | index -= 1; | |
1217 | if predicate(elt) { | |
1218 | SearchWhile::Done(Some(index)) | |
1219 | } else { | |
1220 | SearchWhile::Continue | |
1221 | } | |
1222 | }) | |
1223 | } | |
1a4d82fc JJ |
1224 | } |
1225 | ||
85aaf69f | 1226 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1227 | impl<'a, T> DoubleEndedIterator for $name<'a, T> { |
1228 | #[inline] | |
1229 | fn next_back(&mut self) -> Option<$elem> { | |
1230 | // could be implemented with slices, but this avoids bounds checks | |
1231 | unsafe { | |
d9579d0f AL |
1232 | if mem::size_of::<T>() != 0 { |
1233 | assume(!self.ptr.is_null()); | |
1234 | assume(!self.end.is_null()); | |
1235 | } | |
1a4d82fc JJ |
1236 | if self.end == self.ptr { |
1237 | None | |
1238 | } else { | |
32a655c1 SL |
1239 | Some($mkref!(self.end.pre_dec())) |
1240 | } | |
1241 | } | |
1242 | } | |
cc61c64b XL |
1243 | |
1244 | fn rfind<F>(&mut self, mut predicate: F) -> Option<Self::Item> | |
1245 | where F: FnMut(&Self::Item) -> bool, | |
1246 | { | |
1247 | self.rsearch_while(None, move |elt| { | |
1248 | if predicate(&elt) { | |
1249 | SearchWhile::Done(Some(elt)) | |
1250 | } else { | |
1251 | SearchWhile::Continue | |
1252 | } | |
1253 | }) | |
1254 | } | |
1255 | ||
32a655c1 SL |
1256 | } |
1257 | ||
1258 | // search_while is a generalization of the internal iteration methods. | |
1259 | impl<'a, T> $name<'a, T> { | |
1260 | // search through the iterator's element using the closure `g`. | |
1261 | // if no element was found, return `default`. | |
1262 | fn search_while<Acc, G>(&mut self, default: Acc, mut g: G) -> Acc | |
1263 | where Self: Sized, | |
1264 | G: FnMut($elem) -> SearchWhile<Acc> | |
1265 | { | |
1266 | // manual unrolling is needed when there are conditional exits from the loop | |
1267 | unsafe { | |
1268 | while ptrdistance(self.ptr, self.end) >= 4 { | |
1269 | search_while!(g($mkref!(self.ptr.post_inc()))); | |
1270 | search_while!(g($mkref!(self.ptr.post_inc()))); | |
1271 | search_while!(g($mkref!(self.ptr.post_inc()))); | |
1272 | search_while!(g($mkref!(self.ptr.post_inc()))); | |
1273 | } | |
1274 | while self.ptr != self.end { | |
1275 | search_while!(g($mkref!(self.ptr.post_inc()))); | |
1a4d82fc JJ |
1276 | } |
1277 | } | |
32a655c1 SL |
1278 | default |
1279 | } | |
1280 | ||
1281 | fn rsearch_while<Acc, G>(&mut self, default: Acc, mut g: G) -> Acc | |
1282 | where Self: Sized, | |
1283 | G: FnMut($elem) -> SearchWhile<Acc> | |
1284 | { | |
1285 | unsafe { | |
1286 | while ptrdistance(self.ptr, self.end) >= 4 { | |
1287 | search_while!(g($mkref!(self.end.pre_dec()))); | |
1288 | search_while!(g($mkref!(self.end.pre_dec()))); | |
1289 | search_while!(g($mkref!(self.end.pre_dec()))); | |
1290 | search_while!(g($mkref!(self.end.pre_dec()))); | |
1291 | } | |
1292 | while self.ptr != self.end { | |
1293 | search_while!(g($mkref!(self.end.pre_dec()))); | |
1294 | } | |
1295 | } | |
1296 | default | |
1a4d82fc JJ |
1297 | } |
1298 | } | |
1299 | } | |
1300 | } | |
1301 | ||
1302 | macro_rules! make_slice { | |
d9579d0f AL |
1303 | ($start: expr, $end: expr) => {{ |
1304 | let start = $start; | |
1305 | let diff = ($end as usize).wrapping_sub(start as usize); | |
1306 | if size_from_ptr(start) == 0 { | |
1307 | // use a non-null pointer value | |
1308 | unsafe { from_raw_parts(1 as *const _, diff) } | |
1a4d82fc | 1309 | } else { |
d9579d0f AL |
1310 | let len = diff / size_from_ptr(start); |
1311 | unsafe { from_raw_parts(start, len) } | |
c34b1796 AL |
1312 | } |
1313 | }} | |
1314 | } | |
1315 | ||
1316 | macro_rules! make_mut_slice { | |
d9579d0f AL |
1317 | ($start: expr, $end: expr) => {{ |
1318 | let start = $start; | |
1319 | let diff = ($end as usize).wrapping_sub(start as usize); | |
1320 | if size_from_ptr(start) == 0 { | |
1321 | // use a non-null pointer value | |
1322 | unsafe { from_raw_parts_mut(1 as *mut _, diff) } | |
c34b1796 | 1323 | } else { |
d9579d0f AL |
1324 | let len = diff / size_from_ptr(start); |
1325 | unsafe { from_raw_parts_mut(start, len) } | |
1a4d82fc JJ |
1326 | } |
1327 | }} | |
1328 | } | |
1329 | ||
32a655c1 SL |
1330 | // An enum used for controlling the execution of `.search_while()`. |
1331 | enum SearchWhile<T> { | |
1332 | // Continue searching | |
1333 | Continue, | |
1334 | // Fold is complete and will return this value | |
1335 | Done(T), | |
1336 | } | |
1337 | ||
1338 | // helper macro for search while's control flow | |
1339 | macro_rules! search_while { | |
1340 | ($e:expr) => { | |
1341 | match $e { | |
1342 | SearchWhile::Continue => { } | |
1343 | SearchWhile::Done(done) => return done, | |
1344 | } | |
1345 | } | |
1346 | } | |
1347 | ||
1a4d82fc | 1348 | /// Immutable slice iterator |
a7813a04 | 1349 | /// |
5bcae85e SL |
1350 | /// This struct is created by the [`iter`] method on [slices]. |
1351 | /// | |
a7813a04 XL |
1352 | /// # Examples |
1353 | /// | |
1354 | /// Basic usage: | |
1355 | /// | |
1356 | /// ``` | |
1357 | /// // First, we declare a type which has `iter` method to get the `Iter` struct (&[usize here]): | |
1358 | /// let slice = &[1, 2, 3]; | |
1359 | /// | |
1360 | /// // Then, we iterate over it: | |
1361 | /// for element in slice.iter() { | |
1362 | /// println!("{}", element); | |
1363 | /// } | |
1364 | /// ``` | |
5bcae85e SL |
1365 | /// |
1366 | /// [`iter`]: ../../std/primitive.slice.html#method.iter | |
1367 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1368 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1369 | pub struct Iter<'a, T: 'a> { |
1370 | ptr: *const T, | |
1371 | end: *const T, | |
85aaf69f | 1372 | _marker: marker::PhantomData<&'a T>, |
1a4d82fc JJ |
1373 | } |
1374 | ||
54a0048b SL |
1375 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1376 | impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> { | |
1377 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1378 | f.debug_tuple("Iter") | |
1379 | .field(&self.as_slice()) | |
1380 | .finish() | |
1381 | } | |
1382 | } | |
1383 | ||
92a42be0 | 1384 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 1385 | unsafe impl<'a, T: Sync> Sync for Iter<'a, T> {} |
92a42be0 | 1386 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 AL |
1387 | unsafe impl<'a, T: Sync> Send for Iter<'a, T> {} |
1388 | ||
1a4d82fc JJ |
1389 | impl<'a, T> Iter<'a, T> { |
1390 | /// View the underlying data as a subslice of the original data. | |
1391 | /// | |
1392 | /// This has the same lifetime as the original slice, and so the | |
1393 | /// iterator can continue to be used while this exists. | |
a7813a04 XL |
1394 | /// |
1395 | /// # Examples | |
1396 | /// | |
1397 | /// Basic usage: | |
1398 | /// | |
1399 | /// ``` | |
1400 | /// // First, we declare a type which has the `iter` method to get the `Iter` | |
1401 | /// // struct (&[usize here]): | |
1402 | /// let slice = &[1, 2, 3]; | |
1403 | /// | |
1404 | /// // Then, we get the iterator: | |
1405 | /// let mut iter = slice.iter(); | |
1406 | /// // So if we print what `as_slice` method returns here, we have "[1, 2, 3]": | |
1407 | /// println!("{:?}", iter.as_slice()); | |
1408 | /// | |
1409 | /// // Next, we move to the second element of the slice: | |
1410 | /// iter.next(); | |
1411 | /// // Now `as_slice` returns "[2, 3]": | |
1412 | /// println!("{:?}", iter.as_slice()); | |
1413 | /// ``` | |
e9174d1e | 1414 | #[stable(feature = "iter_to_slice", since = "1.4.0")] |
1a4d82fc | 1415 | pub fn as_slice(&self) -> &'a [T] { |
d9579d0f AL |
1416 | make_slice!(self.ptr, self.end) |
1417 | } | |
1418 | ||
1419 | // Helper function for Iter::nth | |
1420 | fn iter_nth(&mut self, n: usize) -> Option<&'a T> { | |
1421 | match self.as_slice().get(n) { | |
1422 | Some(elem_ref) => unsafe { | |
1423 | self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1)); | |
62682a34 | 1424 | Some(elem_ref) |
d9579d0f AL |
1425 | }, |
1426 | None => { | |
1427 | self.ptr = self.end; | |
1428 | None | |
1429 | } | |
1430 | } | |
1a4d82fc JJ |
1431 | } |
1432 | } | |
1433 | ||
32a655c1 | 1434 | iterator!{struct Iter -> *const T, &'a T, make_ref} |
1a4d82fc | 1435 | |
85aaf69f | 1436 | #[stable(feature = "rust1", since = "1.0.0")] |
476ff2be SL |
1437 | impl<'a, T> ExactSizeIterator for Iter<'a, T> { |
1438 | fn is_empty(&self) -> bool { | |
1439 | self.ptr == self.end | |
1440 | } | |
1441 | } | |
1a4d82fc | 1442 | |
9e0c209e SL |
1443 | #[unstable(feature = "fused", issue = "35602")] |
1444 | impl<'a, T> FusedIterator for Iter<'a, T> {} | |
1445 | ||
c30ab7b3 SL |
1446 | #[unstable(feature = "trusted_len", issue = "37572")] |
1447 | unsafe impl<'a, T> TrustedLen for Iter<'a, T> {} | |
1448 | ||
85aaf69f | 1449 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1450 | impl<'a, T> Clone for Iter<'a, T> { |
85aaf69f | 1451 | fn clone(&self) -> Iter<'a, T> { Iter { ptr: self.ptr, end: self.end, _marker: self._marker } } |
1a4d82fc JJ |
1452 | } |
1453 | ||
7cac9316 | 1454 | #[stable(feature = "slice_iter_as_ref", since = "1.13.0")] |
9e0c209e SL |
1455 | impl<'a, T> AsRef<[T]> for Iter<'a, T> { |
1456 | fn as_ref(&self) -> &[T] { | |
1457 | self.as_slice() | |
1458 | } | |
1459 | } | |
1460 | ||
1a4d82fc | 1461 | /// Mutable slice iterator. |
a7813a04 | 1462 | /// |
5bcae85e SL |
1463 | /// This struct is created by the [`iter_mut`] method on [slices]. |
1464 | /// | |
a7813a04 XL |
1465 | /// # Examples |
1466 | /// | |
1467 | /// Basic usage: | |
1468 | /// | |
1469 | /// ``` | |
1470 | /// // First, we declare a type which has `iter_mut` method to get the `IterMut` | |
1471 | /// // struct (&[usize here]): | |
1472 | /// let mut slice = &mut [1, 2, 3]; | |
1473 | /// | |
1474 | /// // Then, we iterate over it and increment each element value: | |
1475 | /// for element in slice.iter_mut() { | |
1476 | /// *element += 1; | |
1477 | /// } | |
1478 | /// | |
1479 | /// // We now have "[2, 3, 4]": | |
1480 | /// println!("{:?}", slice); | |
1481 | /// ``` | |
5bcae85e SL |
1482 | /// |
1483 | /// [`iter_mut`]: ../../std/primitive.slice.html#method.iter_mut | |
1484 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1485 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1486 | pub struct IterMut<'a, T: 'a> { |
1487 | ptr: *mut T, | |
1488 | end: *mut T, | |
85aaf69f | 1489 | _marker: marker::PhantomData<&'a mut T>, |
1a4d82fc JJ |
1490 | } |
1491 | ||
54a0048b SL |
1492 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1493 | impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> { | |
1494 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1495 | f.debug_tuple("IterMut") | |
1496 | .field(&make_slice!(self.ptr, self.end)) | |
1497 | .finish() | |
1498 | } | |
1499 | } | |
1500 | ||
92a42be0 | 1501 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 1502 | unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {} |
92a42be0 | 1503 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 1504 | unsafe impl<'a, T: Send> Send for IterMut<'a, T> {} |
1a4d82fc | 1505 | |
1a4d82fc JJ |
1506 | impl<'a, T> IterMut<'a, T> { |
1507 | /// View the underlying data as a subslice of the original data. | |
1508 | /// | |
1509 | /// To avoid creating `&mut` references that alias, this is forced | |
1510 | /// to consume the iterator. Consider using the `Slice` and | |
1511 | /// `SliceMut` implementations for obtaining slices with more | |
1512 | /// restricted lifetimes that do not consume the iterator. | |
a7813a04 XL |
1513 | /// |
1514 | /// # Examples | |
1515 | /// | |
1516 | /// Basic usage: | |
1517 | /// | |
1518 | /// ``` | |
1519 | /// // First, we declare a type which has `iter_mut` method to get the `IterMut` | |
1520 | /// // struct (&[usize here]): | |
1521 | /// let mut slice = &mut [1, 2, 3]; | |
1522 | /// | |
1523 | /// { | |
1524 | /// // Then, we get the iterator: | |
1525 | /// let mut iter = slice.iter_mut(); | |
1526 | /// // We move to next element: | |
1527 | /// iter.next(); | |
1528 | /// // So if we print what `into_slice` method returns here, we have "[2, 3]": | |
1529 | /// println!("{:?}", iter.into_slice()); | |
1530 | /// } | |
1531 | /// | |
1532 | /// // Now let's modify a value of the slice: | |
1533 | /// { | |
1534 | /// // First we get back the iterator: | |
1535 | /// let mut iter = slice.iter_mut(); | |
1536 | /// // We change the value of the first element of the slice returned by the `next` method: | |
1537 | /// *iter.next().unwrap() += 1; | |
1538 | /// } | |
1539 | /// // Now slice is "[2, 2, 3]": | |
1540 | /// println!("{:?}", slice); | |
1541 | /// ``` | |
e9174d1e | 1542 | #[stable(feature = "iter_to_slice", since = "1.4.0")] |
1a4d82fc | 1543 | pub fn into_slice(self) -> &'a mut [T] { |
d9579d0f AL |
1544 | make_mut_slice!(self.ptr, self.end) |
1545 | } | |
1546 | ||
1547 | // Helper function for IterMut::nth | |
1548 | fn iter_nth(&mut self, n: usize) -> Option<&'a mut T> { | |
1549 | match make_mut_slice!(self.ptr, self.end).get_mut(n) { | |
1550 | Some(elem_ref) => unsafe { | |
1551 | self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1)); | |
62682a34 | 1552 | Some(elem_ref) |
d9579d0f AL |
1553 | }, |
1554 | None => { | |
1555 | self.ptr = self.end; | |
1556 | None | |
1557 | } | |
1558 | } | |
1a4d82fc JJ |
1559 | } |
1560 | } | |
1561 | ||
32a655c1 | 1562 | iterator!{struct IterMut -> *mut T, &'a mut T, make_ref_mut} |
1a4d82fc | 1563 | |
85aaf69f | 1564 | #[stable(feature = "rust1", since = "1.0.0")] |
476ff2be SL |
1565 | impl<'a, T> ExactSizeIterator for IterMut<'a, T> { |
1566 | fn is_empty(&self) -> bool { | |
1567 | self.ptr == self.end | |
1568 | } | |
1569 | } | |
1a4d82fc | 1570 | |
9e0c209e SL |
1571 | #[unstable(feature = "fused", issue = "35602")] |
1572 | impl<'a, T> FusedIterator for IterMut<'a, T> {} | |
1573 | ||
c30ab7b3 SL |
1574 | #[unstable(feature = "trusted_len", issue = "37572")] |
1575 | unsafe impl<'a, T> TrustedLen for IterMut<'a, T> {} | |
1576 | ||
32a655c1 SL |
1577 | |
1578 | // Return the number of elements of `T` from `start` to `end`. | |
1579 | // Return the arithmetic difference if `T` is zero size. | |
1580 | #[inline(always)] | |
1581 | fn ptrdistance<T>(start: *const T, end: *const T) -> usize { | |
cc61c64b XL |
1582 | match start.offset_to(end) { |
1583 | Some(x) => x as usize, | |
1584 | None => (end as usize).wrapping_sub(start as usize), | |
1585 | } | |
32a655c1 SL |
1586 | } |
1587 | ||
1588 | // Extension methods for raw pointers, used by the iterators | |
1589 | trait PointerExt : Copy { | |
1590 | unsafe fn slice_offset(self, i: isize) -> Self; | |
1591 | ||
cc61c64b | 1592 | /// Increments `self` by 1, but returns the old value. |
32a655c1 SL |
1593 | #[inline(always)] |
1594 | unsafe fn post_inc(&mut self) -> Self { | |
1595 | let current = *self; | |
1596 | *self = self.slice_offset(1); | |
1597 | current | |
1598 | } | |
1599 | ||
cc61c64b | 1600 | /// Decrements `self` by 1, and returns the new value. |
32a655c1 SL |
1601 | #[inline(always)] |
1602 | unsafe fn pre_dec(&mut self) -> Self { | |
1603 | *self = self.slice_offset(-1); | |
1604 | *self | |
1605 | } | |
1606 | } | |
1607 | ||
1608 | impl<T> PointerExt for *const T { | |
1609 | #[inline(always)] | |
1610 | unsafe fn slice_offset(self, i: isize) -> Self { | |
1611 | slice_offset!(self, i) | |
1612 | } | |
1613 | } | |
1614 | ||
1615 | impl<T> PointerExt for *mut T { | |
1616 | #[inline(always)] | |
1617 | unsafe fn slice_offset(self, i: isize) -> Self { | |
1618 | slice_offset!(self, i) | |
1619 | } | |
1620 | } | |
1621 | ||
1a4d82fc JJ |
1622 | /// An internal abstraction over the splitting iterators, so that |
1623 | /// splitn, splitn_mut etc can be implemented once. | |
54a0048b | 1624 | #[doc(hidden)] |
1a4d82fc | 1625 | trait SplitIter: DoubleEndedIterator { |
cc61c64b | 1626 | /// Marks the underlying iterator as complete, extracting the remaining |
1a4d82fc JJ |
1627 | /// portion of the slice. |
1628 | fn finish(&mut self) -> Option<Self::Item>; | |
1629 | } | |
1630 | ||
1631 | /// An iterator over subslices separated by elements that match a predicate | |
1632 | /// function. | |
32a655c1 SL |
1633 | /// |
1634 | /// This struct is created by the [`split`] method on [slices]. | |
1635 | /// | |
1636 | /// [`split`]: ../../std/primitive.slice.html#method.split | |
1637 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1638 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1639 | pub struct Split<'a, T:'a, P> where P: FnMut(&T) -> bool { |
1640 | v: &'a [T], | |
1641 | pred: P, | |
1642 | finished: bool | |
1643 | } | |
1644 | ||
54a0048b SL |
1645 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1646 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for Split<'a, T, P> where P: FnMut(&T) -> bool { | |
1647 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1648 | f.debug_struct("Split") | |
1649 | .field("v", &self.v) | |
1650 | .field("finished", &self.finished) | |
1651 | .finish() | |
1652 | } | |
1653 | } | |
1654 | ||
1a4d82fc | 1655 | // FIXME(#19839) Remove in favor of `#[derive(Clone)]` |
85aaf69f | 1656 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1657 | impl<'a, T, P> Clone for Split<'a, T, P> where P: Clone + FnMut(&T) -> bool { |
1658 | fn clone(&self) -> Split<'a, T, P> { | |
1659 | Split { | |
1660 | v: self.v, | |
1661 | pred: self.pred.clone(), | |
1662 | finished: self.finished, | |
1663 | } | |
1664 | } | |
1665 | } | |
1666 | ||
85aaf69f | 1667 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1668 | impl<'a, T, P> Iterator for Split<'a, T, P> where P: FnMut(&T) -> bool { |
1669 | type Item = &'a [T]; | |
1670 | ||
1671 | #[inline] | |
1672 | fn next(&mut self) -> Option<&'a [T]> { | |
1673 | if self.finished { return None; } | |
1674 | ||
1675 | match self.v.iter().position(|x| (self.pred)(x)) { | |
1676 | None => self.finish(), | |
1677 | Some(idx) => { | |
85aaf69f SL |
1678 | let ret = Some(&self.v[..idx]); |
1679 | self.v = &self.v[idx + 1..]; | |
1a4d82fc JJ |
1680 | ret |
1681 | } | |
1682 | } | |
1683 | } | |
1684 | ||
1685 | #[inline] | |
85aaf69f | 1686 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
1687 | if self.finished { |
1688 | (0, Some(0)) | |
1689 | } else { | |
1690 | (1, Some(self.v.len() + 1)) | |
1691 | } | |
1692 | } | |
1693 | } | |
1694 | ||
85aaf69f | 1695 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1696 | impl<'a, T, P> DoubleEndedIterator for Split<'a, T, P> where P: FnMut(&T) -> bool { |
1697 | #[inline] | |
1698 | fn next_back(&mut self) -> Option<&'a [T]> { | |
1699 | if self.finished { return None; } | |
1700 | ||
1701 | match self.v.iter().rposition(|x| (self.pred)(x)) { | |
1702 | None => self.finish(), | |
1703 | Some(idx) => { | |
85aaf69f SL |
1704 | let ret = Some(&self.v[idx + 1..]); |
1705 | self.v = &self.v[..idx]; | |
1a4d82fc JJ |
1706 | ret |
1707 | } | |
1708 | } | |
1709 | } | |
1710 | } | |
1711 | ||
1712 | impl<'a, T, P> SplitIter for Split<'a, T, P> where P: FnMut(&T) -> bool { | |
1713 | #[inline] | |
1714 | fn finish(&mut self) -> Option<&'a [T]> { | |
1715 | if self.finished { None } else { self.finished = true; Some(self.v) } | |
1716 | } | |
1717 | } | |
1718 | ||
9e0c209e SL |
1719 | #[unstable(feature = "fused", issue = "35602")] |
1720 | impl<'a, T, P> FusedIterator for Split<'a, T, P> where P: FnMut(&T) -> bool {} | |
1721 | ||
1a4d82fc JJ |
1722 | /// An iterator over the subslices of the vector which are separated |
1723 | /// by elements that match `pred`. | |
32a655c1 SL |
1724 | /// |
1725 | /// This struct is created by the [`split_mut`] method on [slices]. | |
1726 | /// | |
1727 | /// [`split_mut`]: ../../std/primitive.slice.html#method.split_mut | |
1728 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1729 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1730 | pub struct SplitMut<'a, T:'a, P> where P: FnMut(&T) -> bool { |
1731 | v: &'a mut [T], | |
1732 | pred: P, | |
1733 | finished: bool | |
1734 | } | |
1735 | ||
54a0048b SL |
1736 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1737 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitMut<'a, T, P> where P: FnMut(&T) -> bool { | |
1738 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1739 | f.debug_struct("SplitMut") | |
1740 | .field("v", &self.v) | |
1741 | .field("finished", &self.finished) | |
1742 | .finish() | |
1743 | } | |
1744 | } | |
1745 | ||
1a4d82fc JJ |
1746 | impl<'a, T, P> SplitIter for SplitMut<'a, T, P> where P: FnMut(&T) -> bool { |
1747 | #[inline] | |
1748 | fn finish(&mut self) -> Option<&'a mut [T]> { | |
1749 | if self.finished { | |
1750 | None | |
1751 | } else { | |
1752 | self.finished = true; | |
1753 | Some(mem::replace(&mut self.v, &mut [])) | |
1754 | } | |
1755 | } | |
1756 | } | |
1757 | ||
85aaf69f | 1758 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1759 | impl<'a, T, P> Iterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool { |
1760 | type Item = &'a mut [T]; | |
1761 | ||
1762 | #[inline] | |
1763 | fn next(&mut self) -> Option<&'a mut [T]> { | |
1764 | if self.finished { return None; } | |
1765 | ||
1766 | let idx_opt = { // work around borrowck limitations | |
1767 | let pred = &mut self.pred; | |
1768 | self.v.iter().position(|x| (*pred)(x)) | |
1769 | }; | |
1770 | match idx_opt { | |
1771 | None => self.finish(), | |
1772 | Some(idx) => { | |
1773 | let tmp = mem::replace(&mut self.v, &mut []); | |
1774 | let (head, tail) = tmp.split_at_mut(idx); | |
85aaf69f | 1775 | self.v = &mut tail[1..]; |
1a4d82fc JJ |
1776 | Some(head) |
1777 | } | |
1778 | } | |
1779 | } | |
1780 | ||
1781 | #[inline] | |
85aaf69f | 1782 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
1783 | if self.finished { |
1784 | (0, Some(0)) | |
1785 | } else { | |
1786 | // if the predicate doesn't match anything, we yield one slice | |
1787 | // if it matches every element, we yield len+1 empty slices. | |
1788 | (1, Some(self.v.len() + 1)) | |
1789 | } | |
1790 | } | |
1791 | } | |
1792 | ||
85aaf69f | 1793 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1794 | impl<'a, T, P> DoubleEndedIterator for SplitMut<'a, T, P> where |
1795 | P: FnMut(&T) -> bool, | |
1796 | { | |
1797 | #[inline] | |
1798 | fn next_back(&mut self) -> Option<&'a mut [T]> { | |
1799 | if self.finished { return None; } | |
1800 | ||
1801 | let idx_opt = { // work around borrowck limitations | |
1802 | let pred = &mut self.pred; | |
1803 | self.v.iter().rposition(|x| (*pred)(x)) | |
1804 | }; | |
1805 | match idx_opt { | |
1806 | None => self.finish(), | |
1807 | Some(idx) => { | |
1808 | let tmp = mem::replace(&mut self.v, &mut []); | |
1809 | let (head, tail) = tmp.split_at_mut(idx); | |
1810 | self.v = head; | |
85aaf69f | 1811 | Some(&mut tail[1..]) |
1a4d82fc JJ |
1812 | } |
1813 | } | |
1814 | } | |
1815 | } | |
1816 | ||
9e0c209e SL |
1817 | #[unstable(feature = "fused", issue = "35602")] |
1818 | impl<'a, T, P> FusedIterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {} | |
1819 | ||
cc61c64b XL |
1820 | /// An iterator over subslices separated by elements that match a predicate |
1821 | /// function, starting from the end of the slice. | |
1822 | /// | |
1823 | /// This struct is created by the [`rsplit`] method on [slices]. | |
1824 | /// | |
1825 | /// [`rsplit`]: ../../std/primitive.slice.html#method.rsplit | |
1826 | /// [slices]: ../../std/primitive.slice.html | |
1827 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1828 | #[derive(Clone)] // Is this correct, or does it incorrectly require `T: Clone`? | |
1829 | pub struct RSplit<'a, T:'a, P> where P: FnMut(&T) -> bool { | |
1830 | inner: Split<'a, T, P> | |
1831 | } | |
1832 | ||
1833 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1834 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplit<'a, T, P> where P: FnMut(&T) -> bool { | |
1835 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1836 | f.debug_struct("RSplit") | |
1837 | .field("v", &self.inner.v) | |
1838 | .field("finished", &self.inner.finished) | |
1839 | .finish() | |
1840 | } | |
1841 | } | |
1842 | ||
1843 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1844 | impl<'a, T, P> Iterator for RSplit<'a, T, P> where P: FnMut(&T) -> bool { | |
1845 | type Item = &'a [T]; | |
1846 | ||
1847 | #[inline] | |
1848 | fn next(&mut self) -> Option<&'a [T]> { | |
1849 | self.inner.next_back() | |
1850 | } | |
1851 | ||
1852 | #[inline] | |
1853 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1854 | self.inner.size_hint() | |
1855 | } | |
1856 | } | |
1857 | ||
1858 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1859 | impl<'a, T, P> DoubleEndedIterator for RSplit<'a, T, P> where P: FnMut(&T) -> bool { | |
1860 | #[inline] | |
1861 | fn next_back(&mut self) -> Option<&'a [T]> { | |
1862 | self.inner.next() | |
1863 | } | |
1864 | } | |
1865 | ||
1866 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1867 | impl<'a, T, P> SplitIter for RSplit<'a, T, P> where P: FnMut(&T) -> bool { | |
1868 | #[inline] | |
1869 | fn finish(&mut self) -> Option<&'a [T]> { | |
1870 | self.inner.finish() | |
1871 | } | |
1872 | } | |
1873 | ||
1874 | //#[unstable(feature = "fused", issue = "35602")] | |
1875 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1876 | impl<'a, T, P> FusedIterator for RSplit<'a, T, P> where P: FnMut(&T) -> bool {} | |
1877 | ||
1878 | /// An iterator over the subslices of the vector which are separated | |
1879 | /// by elements that match `pred`, starting from the end of the slice. | |
1880 | /// | |
1881 | /// This struct is created by the [`rsplit_mut`] method on [slices]. | |
1882 | /// | |
1883 | /// [`rsplit_mut`]: ../../std/primitive.slice.html#method.rsplit_mut | |
1884 | /// [slices]: ../../std/primitive.slice.html | |
1885 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1886 | pub struct RSplitMut<'a, T:'a, P> where P: FnMut(&T) -> bool { | |
1887 | inner: SplitMut<'a, T, P> | |
1888 | } | |
1889 | ||
1890 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1891 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool { | |
1892 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1893 | f.debug_struct("RSplitMut") | |
1894 | .field("v", &self.inner.v) | |
1895 | .field("finished", &self.inner.finished) | |
1896 | .finish() | |
1897 | } | |
1898 | } | |
1899 | ||
1900 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1901 | impl<'a, T, P> SplitIter for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool { | |
1902 | #[inline] | |
1903 | fn finish(&mut self) -> Option<&'a mut [T]> { | |
1904 | self.inner.finish() | |
1905 | } | |
1906 | } | |
1907 | ||
1908 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1909 | impl<'a, T, P> Iterator for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool { | |
1910 | type Item = &'a mut [T]; | |
1911 | ||
1912 | #[inline] | |
1913 | fn next(&mut self) -> Option<&'a mut [T]> { | |
1914 | self.inner.next_back() | |
1915 | } | |
1916 | ||
1917 | #[inline] | |
1918 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1919 | self.inner.size_hint() | |
1920 | } | |
1921 | } | |
1922 | ||
1923 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1924 | impl<'a, T, P> DoubleEndedIterator for RSplitMut<'a, T, P> where | |
1925 | P: FnMut(&T) -> bool, | |
1926 | { | |
1927 | #[inline] | |
1928 | fn next_back(&mut self) -> Option<&'a mut [T]> { | |
1929 | self.inner.next() | |
1930 | } | |
1931 | } | |
1932 | ||
1933 | //#[unstable(feature = "fused", issue = "35602")] | |
1934 | #[unstable(feature = "slice_rsplit", issue = "41020")] | |
1935 | impl<'a, T, P> FusedIterator for RSplitMut<'a, T, P> where P: FnMut(&T) -> bool {} | |
1936 | ||
1a4d82fc JJ |
1937 | /// An private iterator over subslices separated by elements that |
1938 | /// match a predicate function, splitting at most a fixed number of | |
1939 | /// times. | |
54a0048b | 1940 | #[derive(Debug)] |
1a4d82fc JJ |
1941 | struct GenericSplitN<I> { |
1942 | iter: I, | |
85aaf69f | 1943 | count: usize, |
1a4d82fc JJ |
1944 | } |
1945 | ||
1946 | impl<T, I: SplitIter<Item=T>> Iterator for GenericSplitN<I> { | |
1947 | type Item = T; | |
1948 | ||
1949 | #[inline] | |
1950 | fn next(&mut self) -> Option<T> { | |
c34b1796 AL |
1951 | match self.count { |
1952 | 0 => None, | |
1953 | 1 => { self.count -= 1; self.iter.finish() } | |
cc61c64b | 1954 | _ => { self.count -= 1; self.iter.next() } |
1a4d82fc JJ |
1955 | } |
1956 | } | |
1957 | ||
1958 | #[inline] | |
85aaf69f | 1959 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc | 1960 | let (lower, upper_opt) = self.iter.size_hint(); |
c34b1796 | 1961 | (lower, upper_opt.map(|upper| cmp::min(self.count, upper))) |
1a4d82fc JJ |
1962 | } |
1963 | } | |
1964 | ||
1965 | /// An iterator over subslices separated by elements that match a predicate | |
1966 | /// function, limited to a given number of splits. | |
32a655c1 SL |
1967 | /// |
1968 | /// This struct is created by the [`splitn`] method on [slices]. | |
1969 | /// | |
1970 | /// [`splitn`]: ../../std/primitive.slice.html#method.splitn | |
1971 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1972 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1973 | pub struct SplitN<'a, T: 'a, P> where P: FnMut(&T) -> bool { |
1974 | inner: GenericSplitN<Split<'a, T, P>> | |
1975 | } | |
1976 | ||
54a0048b SL |
1977 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1978 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitN<'a, T, P> where P: FnMut(&T) -> bool { | |
1979 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
1980 | f.debug_struct("SplitN") | |
1981 | .field("inner", &self.inner) | |
1982 | .finish() | |
1983 | } | |
1984 | } | |
1985 | ||
1a4d82fc JJ |
1986 | /// An iterator over subslices separated by elements that match a |
1987 | /// predicate function, limited to a given number of splits, starting | |
1988 | /// from the end of the slice. | |
32a655c1 SL |
1989 | /// |
1990 | /// This struct is created by the [`rsplitn`] method on [slices]. | |
1991 | /// | |
1992 | /// [`rsplitn`]: ../../std/primitive.slice.html#method.rsplitn | |
1993 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 1994 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1995 | pub struct RSplitN<'a, T: 'a, P> where P: FnMut(&T) -> bool { |
cc61c64b | 1996 | inner: GenericSplitN<RSplit<'a, T, P>> |
1a4d82fc JJ |
1997 | } |
1998 | ||
54a0048b SL |
1999 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
2000 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplitN<'a, T, P> where P: FnMut(&T) -> bool { | |
2001 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
2002 | f.debug_struct("RSplitN") | |
2003 | .field("inner", &self.inner) | |
2004 | .finish() | |
2005 | } | |
2006 | } | |
2007 | ||
1a4d82fc JJ |
2008 | /// An iterator over subslices separated by elements that match a predicate |
2009 | /// function, limited to a given number of splits. | |
32a655c1 SL |
2010 | /// |
2011 | /// This struct is created by the [`splitn_mut`] method on [slices]. | |
2012 | /// | |
2013 | /// [`splitn_mut`]: ../../std/primitive.slice.html#method.splitn_mut | |
2014 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 2015 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2016 | pub struct SplitNMut<'a, T: 'a, P> where P: FnMut(&T) -> bool { |
2017 | inner: GenericSplitN<SplitMut<'a, T, P>> | |
2018 | } | |
2019 | ||
54a0048b SL |
2020 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
2021 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitNMut<'a, T, P> where P: FnMut(&T) -> bool { | |
2022 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
2023 | f.debug_struct("SplitNMut") | |
2024 | .field("inner", &self.inner) | |
2025 | .finish() | |
2026 | } | |
2027 | } | |
2028 | ||
1a4d82fc JJ |
2029 | /// An iterator over subslices separated by elements that match a |
2030 | /// predicate function, limited to a given number of splits, starting | |
2031 | /// from the end of the slice. | |
32a655c1 SL |
2032 | /// |
2033 | /// This struct is created by the [`rsplitn_mut`] method on [slices]. | |
2034 | /// | |
2035 | /// [`rsplitn_mut`]: ../../std/primitive.slice.html#method.rsplitn_mut | |
2036 | /// [slices]: ../../std/primitive.slice.html | |
85aaf69f | 2037 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 2038 | pub struct RSplitNMut<'a, T: 'a, P> where P: FnMut(&T) -> bool { |
cc61c64b | 2039 | inner: GenericSplitN<RSplitMut<'a, T, P>> |
1a4d82fc JJ |
2040 | } |
2041 | ||
54a0048b SL |
2042 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
2043 | impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplitNMut<'a, T, P> where P: FnMut(&T) -> bool { | |
2044 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
2045 | f.debug_struct("RSplitNMut") | |
2046 | .field("inner", &self.inner) | |
2047 | .finish() | |
2048 | } | |
2049 | } | |
2050 | ||
1a4d82fc JJ |
2051 | macro_rules! forward_iterator { |
2052 | ($name:ident: $elem:ident, $iter_of:ty) => { | |
85aaf69f | 2053 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2054 | impl<'a, $elem, P> Iterator for $name<'a, $elem, P> where |
2055 | P: FnMut(&T) -> bool | |
2056 | { | |
2057 | type Item = $iter_of; | |
2058 | ||
2059 | #[inline] | |
2060 | fn next(&mut self) -> Option<$iter_of> { | |
2061 | self.inner.next() | |
2062 | } | |
2063 | ||
2064 | #[inline] | |
85aaf69f | 2065 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
2066 | self.inner.size_hint() |
2067 | } | |
2068 | } | |
9e0c209e SL |
2069 | |
2070 | #[unstable(feature = "fused", issue = "35602")] | |
2071 | impl<'a, $elem, P> FusedIterator for $name<'a, $elem, P> | |
2072 | where P: FnMut(&T) -> bool {} | |
1a4d82fc JJ |
2073 | } |
2074 | } | |
2075 | ||
2076 | forward_iterator! { SplitN: T, &'a [T] } | |
2077 | forward_iterator! { RSplitN: T, &'a [T] } | |
2078 | forward_iterator! { SplitNMut: T, &'a mut [T] } | |
2079 | forward_iterator! { RSplitNMut: T, &'a mut [T] } | |
2080 | ||
2081 | /// An iterator over overlapping subslices of length `size`. | |
32a655c1 SL |
2082 | /// |
2083 | /// This struct is created by the [`windows`] method on [slices]. | |
2084 | /// | |
2085 | /// [`windows`]: ../../std/primitive.slice.html#method.windows | |
2086 | /// [slices]: ../../std/primitive.slice.html | |
54a0048b | 2087 | #[derive(Debug)] |
85aaf69f | 2088 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2089 | pub struct Windows<'a, T:'a> { |
2090 | v: &'a [T], | |
85aaf69f | 2091 | size: usize |
1a4d82fc JJ |
2092 | } |
2093 | ||
c34b1796 AL |
2094 | // FIXME(#19839) Remove in favor of `#[derive(Clone)]` |
2095 | #[stable(feature = "rust1", since = "1.0.0")] | |
2096 | impl<'a, T> Clone for Windows<'a, T> { | |
2097 | fn clone(&self) -> Windows<'a, T> { | |
2098 | Windows { | |
2099 | v: self.v, | |
2100 | size: self.size, | |
2101 | } | |
2102 | } | |
2103 | } | |
2104 | ||
85aaf69f | 2105 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2106 | impl<'a, T> Iterator for Windows<'a, T> { |
2107 | type Item = &'a [T]; | |
2108 | ||
2109 | #[inline] | |
2110 | fn next(&mut self) -> Option<&'a [T]> { | |
2111 | if self.size > self.v.len() { | |
2112 | None | |
2113 | } else { | |
85aaf69f | 2114 | let ret = Some(&self.v[..self.size]); |
1a4d82fc JJ |
2115 | self.v = &self.v[1..]; |
2116 | ret | |
2117 | } | |
2118 | } | |
2119 | ||
2120 | #[inline] | |
85aaf69f | 2121 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
2122 | if self.size > self.v.len() { |
2123 | (0, Some(0)) | |
2124 | } else { | |
85aaf69f SL |
2125 | let size = self.v.len() - self.size + 1; |
2126 | (size, Some(size)) | |
2127 | } | |
2128 | } | |
e9174d1e SL |
2129 | |
2130 | #[inline] | |
2131 | fn count(self) -> usize { | |
3157f602 | 2132 | self.len() |
e9174d1e SL |
2133 | } |
2134 | ||
2135 | #[inline] | |
2136 | fn nth(&mut self, n: usize) -> Option<Self::Item> { | |
2137 | let (end, overflow) = self.size.overflowing_add(n); | |
2138 | if end > self.v.len() || overflow { | |
2139 | self.v = &[]; | |
2140 | None | |
2141 | } else { | |
2142 | let nth = &self.v[n..end]; | |
2143 | self.v = &self.v[n+1..]; | |
2144 | Some(nth) | |
2145 | } | |
2146 | } | |
2147 | ||
2148 | #[inline] | |
2149 | fn last(self) -> Option<Self::Item> { | |
2150 | if self.size > self.v.len() { | |
2151 | None | |
2152 | } else { | |
2153 | let start = self.v.len() - self.size; | |
2154 | Some(&self.v[start..]) | |
2155 | } | |
2156 | } | |
85aaf69f SL |
2157 | } |
2158 | ||
2159 | #[stable(feature = "rust1", since = "1.0.0")] | |
2160 | impl<'a, T> DoubleEndedIterator for Windows<'a, T> { | |
2161 | #[inline] | |
2162 | fn next_back(&mut self) -> Option<&'a [T]> { | |
2163 | if self.size > self.v.len() { | |
2164 | None | |
2165 | } else { | |
2166 | let ret = Some(&self.v[self.v.len()-self.size..]); | |
2167 | self.v = &self.v[..self.v.len()-1]; | |
2168 | ret | |
2169 | } | |
2170 | } | |
2171 | } | |
2172 | ||
2173 | #[stable(feature = "rust1", since = "1.0.0")] | |
2174 | impl<'a, T> ExactSizeIterator for Windows<'a, T> {} | |
2175 | ||
9e0c209e SL |
2176 | #[unstable(feature = "fused", issue = "35602")] |
2177 | impl<'a, T> FusedIterator for Windows<'a, T> {} | |
2178 | ||
1a4d82fc JJ |
2179 | /// An iterator over a slice in (non-overlapping) chunks (`size` elements at a |
2180 | /// time). | |
2181 | /// | |
2182 | /// When the slice len is not evenly divided by the chunk size, the last slice | |
2183 | /// of the iteration will be the remainder. | |
32a655c1 SL |
2184 | /// |
2185 | /// This struct is created by the [`chunks`] method on [slices]. | |
2186 | /// | |
2187 | /// [`chunks`]: ../../std/primitive.slice.html#method.chunks | |
2188 | /// [slices]: ../../std/primitive.slice.html | |
54a0048b | 2189 | #[derive(Debug)] |
85aaf69f | 2190 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2191 | pub struct Chunks<'a, T:'a> { |
2192 | v: &'a [T], | |
85aaf69f | 2193 | size: usize |
1a4d82fc JJ |
2194 | } |
2195 | ||
c34b1796 AL |
2196 | // FIXME(#19839) Remove in favor of `#[derive(Clone)]` |
2197 | #[stable(feature = "rust1", since = "1.0.0")] | |
2198 | impl<'a, T> Clone for Chunks<'a, T> { | |
2199 | fn clone(&self) -> Chunks<'a, T> { | |
2200 | Chunks { | |
2201 | v: self.v, | |
2202 | size: self.size, | |
2203 | } | |
2204 | } | |
2205 | } | |
2206 | ||
85aaf69f | 2207 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2208 | impl<'a, T> Iterator for Chunks<'a, T> { |
2209 | type Item = &'a [T]; | |
2210 | ||
2211 | #[inline] | |
2212 | fn next(&mut self) -> Option<&'a [T]> { | |
9346a6ac | 2213 | if self.v.is_empty() { |
1a4d82fc JJ |
2214 | None |
2215 | } else { | |
2216 | let chunksz = cmp::min(self.v.len(), self.size); | |
2217 | let (fst, snd) = self.v.split_at(chunksz); | |
2218 | self.v = snd; | |
2219 | Some(fst) | |
2220 | } | |
2221 | } | |
2222 | ||
2223 | #[inline] | |
85aaf69f | 2224 | fn size_hint(&self) -> (usize, Option<usize>) { |
9346a6ac | 2225 | if self.v.is_empty() { |
1a4d82fc JJ |
2226 | (0, Some(0)) |
2227 | } else { | |
2228 | let n = self.v.len() / self.size; | |
2229 | let rem = self.v.len() % self.size; | |
2230 | let n = if rem > 0 { n+1 } else { n }; | |
2231 | (n, Some(n)) | |
2232 | } | |
2233 | } | |
e9174d1e SL |
2234 | |
2235 | #[inline] | |
2236 | fn count(self) -> usize { | |
3157f602 | 2237 | self.len() |
e9174d1e SL |
2238 | } |
2239 | ||
2240 | #[inline] | |
2241 | fn nth(&mut self, n: usize) -> Option<Self::Item> { | |
2242 | let (start, overflow) = n.overflowing_mul(self.size); | |
2243 | if start >= self.v.len() || overflow { | |
2244 | self.v = &[]; | |
2245 | None | |
2246 | } else { | |
2247 | let end = match start.checked_add(self.size) { | |
2248 | Some(sum) => cmp::min(self.v.len(), sum), | |
2249 | None => self.v.len(), | |
2250 | }; | |
2251 | let nth = &self.v[start..end]; | |
2252 | self.v = &self.v[end..]; | |
2253 | Some(nth) | |
2254 | } | |
2255 | } | |
2256 | ||
2257 | #[inline] | |
2258 | fn last(self) -> Option<Self::Item> { | |
2259 | if self.v.is_empty() { | |
2260 | None | |
2261 | } else { | |
2262 | let start = (self.v.len() - 1) / self.size * self.size; | |
2263 | Some(&self.v[start..]) | |
2264 | } | |
2265 | } | |
1a4d82fc JJ |
2266 | } |
2267 | ||
85aaf69f | 2268 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2269 | impl<'a, T> DoubleEndedIterator for Chunks<'a, T> { |
2270 | #[inline] | |
2271 | fn next_back(&mut self) -> Option<&'a [T]> { | |
9346a6ac | 2272 | if self.v.is_empty() { |
1a4d82fc JJ |
2273 | None |
2274 | } else { | |
2275 | let remainder = self.v.len() % self.size; | |
2276 | let chunksz = if remainder != 0 { remainder } else { self.size }; | |
2277 | let (fst, snd) = self.v.split_at(self.v.len() - chunksz); | |
2278 | self.v = fst; | |
2279 | Some(snd) | |
2280 | } | |
2281 | } | |
2282 | } | |
2283 | ||
85aaf69f SL |
2284 | #[stable(feature = "rust1", since = "1.0.0")] |
2285 | impl<'a, T> ExactSizeIterator for Chunks<'a, T> {} | |
2286 | ||
9e0c209e SL |
2287 | #[unstable(feature = "fused", issue = "35602")] |
2288 | impl<'a, T> FusedIterator for Chunks<'a, T> {} | |
2289 | ||
1a4d82fc JJ |
2290 | /// An iterator over a slice in (non-overlapping) mutable chunks (`size` |
2291 | /// elements at a time). When the slice len is not evenly divided by the chunk | |
2292 | /// size, the last slice of the iteration will be the remainder. | |
32a655c1 SL |
2293 | /// |
2294 | /// This struct is created by the [`chunks_mut`] method on [slices]. | |
2295 | /// | |
2296 | /// [`chunks_mut`]: ../../std/primitive.slice.html#method.chunks_mut | |
2297 | /// [slices]: ../../std/primitive.slice.html | |
54a0048b | 2298 | #[derive(Debug)] |
85aaf69f | 2299 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2300 | pub struct ChunksMut<'a, T:'a> { |
2301 | v: &'a mut [T], | |
85aaf69f | 2302 | chunk_size: usize |
1a4d82fc JJ |
2303 | } |
2304 | ||
85aaf69f | 2305 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2306 | impl<'a, T> Iterator for ChunksMut<'a, T> { |
2307 | type Item = &'a mut [T]; | |
2308 | ||
2309 | #[inline] | |
2310 | fn next(&mut self) -> Option<&'a mut [T]> { | |
9346a6ac | 2311 | if self.v.is_empty() { |
1a4d82fc JJ |
2312 | None |
2313 | } else { | |
2314 | let sz = cmp::min(self.v.len(), self.chunk_size); | |
2315 | let tmp = mem::replace(&mut self.v, &mut []); | |
2316 | let (head, tail) = tmp.split_at_mut(sz); | |
2317 | self.v = tail; | |
2318 | Some(head) | |
2319 | } | |
2320 | } | |
2321 | ||
2322 | #[inline] | |
85aaf69f | 2323 | fn size_hint(&self) -> (usize, Option<usize>) { |
9346a6ac | 2324 | if self.v.is_empty() { |
1a4d82fc JJ |
2325 | (0, Some(0)) |
2326 | } else { | |
2327 | let n = self.v.len() / self.chunk_size; | |
2328 | let rem = self.v.len() % self.chunk_size; | |
2329 | let n = if rem > 0 { n + 1 } else { n }; | |
2330 | (n, Some(n)) | |
2331 | } | |
2332 | } | |
e9174d1e SL |
2333 | |
2334 | #[inline] | |
2335 | fn count(self) -> usize { | |
3157f602 | 2336 | self.len() |
e9174d1e SL |
2337 | } |
2338 | ||
2339 | #[inline] | |
2340 | fn nth(&mut self, n: usize) -> Option<&'a mut [T]> { | |
2341 | let (start, overflow) = n.overflowing_mul(self.chunk_size); | |
2342 | if start >= self.v.len() || overflow { | |
2343 | self.v = &mut []; | |
2344 | None | |
2345 | } else { | |
2346 | let end = match start.checked_add(self.chunk_size) { | |
2347 | Some(sum) => cmp::min(self.v.len(), sum), | |
2348 | None => self.v.len(), | |
2349 | }; | |
2350 | let tmp = mem::replace(&mut self.v, &mut []); | |
2351 | let (head, tail) = tmp.split_at_mut(end); | |
2352 | let (_, nth) = head.split_at_mut(start); | |
2353 | self.v = tail; | |
2354 | Some(nth) | |
2355 | } | |
2356 | } | |
2357 | ||
2358 | #[inline] | |
2359 | fn last(self) -> Option<Self::Item> { | |
2360 | if self.v.is_empty() { | |
2361 | None | |
2362 | } else { | |
2363 | let start = (self.v.len() - 1) / self.chunk_size * self.chunk_size; | |
2364 | Some(&mut self.v[start..]) | |
2365 | } | |
2366 | } | |
1a4d82fc JJ |
2367 | } |
2368 | ||
85aaf69f | 2369 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
2370 | impl<'a, T> DoubleEndedIterator for ChunksMut<'a, T> { |
2371 | #[inline] | |
2372 | fn next_back(&mut self) -> Option<&'a mut [T]> { | |
9346a6ac | 2373 | if self.v.is_empty() { |
1a4d82fc JJ |
2374 | None |
2375 | } else { | |
2376 | let remainder = self.v.len() % self.chunk_size; | |
2377 | let sz = if remainder != 0 { remainder } else { self.chunk_size }; | |
2378 | let tmp = mem::replace(&mut self.v, &mut []); | |
2379 | let tmp_len = tmp.len(); | |
2380 | let (head, tail) = tmp.split_at_mut(tmp_len - sz); | |
2381 | self.v = head; | |
2382 | Some(tail) | |
2383 | } | |
2384 | } | |
2385 | } | |
2386 | ||
85aaf69f SL |
2387 | #[stable(feature = "rust1", since = "1.0.0")] |
2388 | impl<'a, T> ExactSizeIterator for ChunksMut<'a, T> {} | |
1a4d82fc | 2389 | |
9e0c209e SL |
2390 | #[unstable(feature = "fused", issue = "35602")] |
2391 | impl<'a, T> FusedIterator for ChunksMut<'a, T> {} | |
2392 | ||
1a4d82fc JJ |
2393 | // |
2394 | // Free functions | |
2395 | // | |
2396 | ||
85aaf69f SL |
2397 | /// Forms a slice from a pointer and a length. |
2398 | /// | |
2399 | /// The `len` argument is the number of **elements**, not the number of bytes. | |
2400 | /// | |
b039eaaf | 2401 | /// # Safety |
c1a9b12d | 2402 | /// |
85aaf69f SL |
2403 | /// This function is unsafe as there is no guarantee that the given pointer is |
2404 | /// valid for `len` elements, nor whether the lifetime inferred is a suitable | |
2405 | /// lifetime for the returned slice. | |
2406 | /// | |
7cac9316 XL |
2407 | /// `p` must be non-null, even for zero-length slices, because non-zero bits |
2408 | /// are required to distinguish between a zero-length slice within `Some()` | |
2409 | /// from `None`. `p` can be a bogus non-dereferencable pointer, such as `0x1`, | |
2410 | /// for zero-length slices, though. | |
c1a9b12d | 2411 | /// |
85aaf69f SL |
2412 | /// # Caveat |
2413 | /// | |
2414 | /// The lifetime for the returned slice is inferred from its usage. To | |
2415 | /// prevent accidental misuse, it's suggested to tie the lifetime to whichever | |
2416 | /// source lifetime is safe in the context, such as by providing a helper | |
2417 | /// function taking the lifetime of a host value for the slice, or by explicit | |
2418 | /// annotation. | |
2419 | /// | |
c34b1796 | 2420 | /// # Examples |
85aaf69f | 2421 | /// |
c34b1796 | 2422 | /// ``` |
85aaf69f SL |
2423 | /// use std::slice; |
2424 | /// | |
2425 | /// // manifest a slice out of thin air! | |
2426 | /// let ptr = 0x1234 as *const usize; | |
2427 | /// let amt = 10; | |
2428 | /// unsafe { | |
2429 | /// let slice = slice::from_raw_parts(ptr, amt); | |
2430 | /// } | |
2431 | /// ``` | |
2432 | #[inline] | |
c34b1796 | 2433 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 2434 | pub unsafe fn from_raw_parts<'a, T>(p: *const T, len: usize) -> &'a [T] { |
54a0048b | 2435 | mem::transmute(Repr { data: p, len: len }) |
85aaf69f SL |
2436 | } |
2437 | ||
2438 | /// Performs the same functionality as `from_raw_parts`, except that a mutable | |
2439 | /// slice is returned. | |
2440 | /// | |
2441 | /// This function is unsafe for the same reasons as `from_raw_parts`, as well | |
2442 | /// as not being able to provide a non-aliasing guarantee of the returned | |
7cac9316 XL |
2443 | /// mutable slice. `p` must be non-null even for zero-length slices as with |
2444 | /// `from_raw_parts`. | |
85aaf69f | 2445 | #[inline] |
c34b1796 | 2446 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 2447 | pub unsafe fn from_raw_parts_mut<'a, T>(p: *mut T, len: usize) -> &'a mut [T] { |
54a0048b | 2448 | mem::transmute(Repr { data: p, len: len }) |
85aaf69f SL |
2449 | } |
2450 | ||
cc61c64b XL |
2451 | // This function is public only because there is no other way to unit test heapsort. |
2452 | #[unstable(feature = "sort_internals", reason = "internal to sort module", issue = "0")] | |
2453 | #[doc(hidden)] | |
2454 | pub fn heapsort<T, F>(v: &mut [T], mut is_less: F) | |
2455 | where F: FnMut(&T, &T) -> bool | |
2456 | { | |
2457 | sort::heapsort(v, &mut is_less); | |
2458 | } | |
2459 | ||
1a4d82fc | 2460 | // |
54a0048b | 2461 | // Comparison traits |
1a4d82fc JJ |
2462 | // |
2463 | ||
54a0048b | 2464 | extern { |
cc61c64b | 2465 | /// Calls implementation provided memcmp. |
54a0048b SL |
2466 | /// |
2467 | /// Interprets the data as u8. | |
2468 | /// | |
cc61c64b | 2469 | /// Returns 0 for equal, < 0 for less than and > 0 for greater |
54a0048b SL |
2470 | /// than. |
2471 | // FIXME(#32610): Return type should be c_int | |
2472 | fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32; | |
2473 | } | |
1a4d82fc | 2474 | |
54a0048b SL |
2475 | #[stable(feature = "rust1", since = "1.0.0")] |
2476 | impl<A, B> PartialEq<[B]> for [A] where A: PartialEq<B> { | |
2477 | fn eq(&self, other: &[B]) -> bool { | |
2478 | SlicePartialEq::equal(self, other) | |
1a4d82fc JJ |
2479 | } |
2480 | ||
54a0048b SL |
2481 | fn ne(&self, other: &[B]) -> bool { |
2482 | SlicePartialEq::not_equal(self, other) | |
1a4d82fc | 2483 | } |
54a0048b | 2484 | } |
1a4d82fc | 2485 | |
54a0048b SL |
2486 | #[stable(feature = "rust1", since = "1.0.0")] |
2487 | impl<T: Eq> Eq for [T] {} | |
2488 | ||
8bb4bdeb | 2489 | /// Implements comparison of vectors lexicographically. |
54a0048b SL |
2490 | #[stable(feature = "rust1", since = "1.0.0")] |
2491 | impl<T: Ord> Ord for [T] { | |
2492 | fn cmp(&self, other: &[T]) -> Ordering { | |
2493 | SliceOrd::compare(self, other) | |
1a4d82fc JJ |
2494 | } |
2495 | } | |
2496 | ||
8bb4bdeb | 2497 | /// Implements comparison of vectors lexicographically. |
54a0048b SL |
2498 | #[stable(feature = "rust1", since = "1.0.0")] |
2499 | impl<T: PartialOrd> PartialOrd for [T] { | |
2500 | fn partial_cmp(&self, other: &[T]) -> Option<Ordering> { | |
2501 | SlicePartialOrd::partial_compare(self, other) | |
2502 | } | |
2503 | } | |
1a4d82fc | 2504 | |
54a0048b SL |
2505 | #[doc(hidden)] |
2506 | // intermediate trait for specialization of slice's PartialEq | |
2507 | trait SlicePartialEq<B> { | |
2508 | fn equal(&self, other: &[B]) -> bool; | |
9e0c209e SL |
2509 | |
2510 | fn not_equal(&self, other: &[B]) -> bool { !self.equal(other) } | |
54a0048b | 2511 | } |
1a4d82fc | 2512 | |
54a0048b SL |
2513 | // Generic slice equality |
2514 | impl<A, B> SlicePartialEq<B> for [A] | |
2515 | where A: PartialEq<B> | |
2516 | { | |
2517 | default fn equal(&self, other: &[B]) -> bool { | |
c1a9b12d SL |
2518 | if self.len() != other.len() { |
2519 | return false; | |
2520 | } | |
2521 | ||
2522 | for i in 0..self.len() { | |
2523 | if !self[i].eq(&other[i]) { | |
2524 | return false; | |
2525 | } | |
2526 | } | |
2527 | ||
2528 | true | |
1a4d82fc | 2529 | } |
1a4d82fc JJ |
2530 | } |
2531 | ||
54a0048b SL |
2532 | // Use memcmp for bytewise equality when the types allow |
2533 | impl<A> SlicePartialEq<A> for [A] | |
2534 | where A: PartialEq<A> + BytewiseEquality | |
2535 | { | |
2536 | fn equal(&self, other: &[A]) -> bool { | |
2537 | if self.len() != other.len() { | |
2538 | return false; | |
2539 | } | |
3157f602 XL |
2540 | if self.as_ptr() == other.as_ptr() { |
2541 | return true; | |
2542 | } | |
54a0048b SL |
2543 | unsafe { |
2544 | let size = mem::size_of_val(self); | |
2545 | memcmp(self.as_ptr() as *const u8, | |
2546 | other.as_ptr() as *const u8, size) == 0 | |
2547 | } | |
2548 | } | |
54a0048b SL |
2549 | } |
2550 | ||
2551 | #[doc(hidden)] | |
2552 | // intermediate trait for specialization of slice's PartialOrd | |
2553 | trait SlicePartialOrd<B> { | |
2554 | fn partial_compare(&self, other: &[B]) -> Option<Ordering>; | |
2555 | } | |
2556 | ||
2557 | impl<A> SlicePartialOrd<A> for [A] | |
2558 | where A: PartialOrd | |
2559 | { | |
2560 | default fn partial_compare(&self, other: &[A]) -> Option<Ordering> { | |
b039eaaf SL |
2561 | let l = cmp::min(self.len(), other.len()); |
2562 | ||
2563 | // Slice to the loop iteration range to enable bound check | |
2564 | // elimination in the compiler | |
2565 | let lhs = &self[..l]; | |
2566 | let rhs = &other[..l]; | |
2567 | ||
2568 | for i in 0..l { | |
54a0048b SL |
2569 | match lhs[i].partial_cmp(&rhs[i]) { |
2570 | Some(Ordering::Equal) => (), | |
b039eaaf SL |
2571 | non_eq => return non_eq, |
2572 | } | |
2573 | } | |
2574 | ||
54a0048b | 2575 | self.len().partial_cmp(&other.len()) |
1a4d82fc JJ |
2576 | } |
2577 | } | |
2578 | ||
8bb4bdeb XL |
2579 | impl<A> SlicePartialOrd<A> for [A] |
2580 | where A: Ord | |
2581 | { | |
2582 | default fn partial_compare(&self, other: &[A]) -> Option<Ordering> { | |
54a0048b SL |
2583 | Some(SliceOrd::compare(self, other)) |
2584 | } | |
2585 | } | |
2586 | ||
2587 | #[doc(hidden)] | |
2588 | // intermediate trait for specialization of slice's Ord | |
2589 | trait SliceOrd<B> { | |
2590 | fn compare(&self, other: &[B]) -> Ordering; | |
2591 | } | |
2592 | ||
2593 | impl<A> SliceOrd<A> for [A] | |
2594 | where A: Ord | |
2595 | { | |
2596 | default fn compare(&self, other: &[A]) -> Ordering { | |
b039eaaf SL |
2597 | let l = cmp::min(self.len(), other.len()); |
2598 | ||
2599 | // Slice to the loop iteration range to enable bound check | |
2600 | // elimination in the compiler | |
2601 | let lhs = &self[..l]; | |
2602 | let rhs = &other[..l]; | |
2603 | ||
2604 | for i in 0..l { | |
54a0048b SL |
2605 | match lhs[i].cmp(&rhs[i]) { |
2606 | Ordering::Equal => (), | |
b039eaaf SL |
2607 | non_eq => return non_eq, |
2608 | } | |
2609 | } | |
2610 | ||
54a0048b SL |
2611 | self.len().cmp(&other.len()) |
2612 | } | |
2613 | } | |
2614 | ||
2615 | // memcmp compares a sequence of unsigned bytes lexicographically. | |
2616 | // this matches the order we want for [u8], but no others (not even [i8]). | |
2617 | impl SliceOrd<u8> for [u8] { | |
2618 | #[inline] | |
2619 | fn compare(&self, other: &[u8]) -> Ordering { | |
2620 | let order = unsafe { | |
2621 | memcmp(self.as_ptr(), other.as_ptr(), | |
2622 | cmp::min(self.len(), other.len())) | |
2623 | }; | |
2624 | if order == 0 { | |
2625 | self.len().cmp(&other.len()) | |
2626 | } else if order < 0 { | |
2627 | Less | |
2628 | } else { | |
2629 | Greater | |
2630 | } | |
2631 | } | |
2632 | } | |
2633 | ||
2634 | #[doc(hidden)] | |
2635 | /// Trait implemented for types that can be compared for equality using | |
2636 | /// their bytewise representation | |
2637 | trait BytewiseEquality { } | |
2638 | ||
2639 | macro_rules! impl_marker_for { | |
2640 | ($traitname:ident, $($ty:ty)*) => { | |
2641 | $( | |
2642 | impl $traitname for $ty { } | |
2643 | )* | |
1a4d82fc JJ |
2644 | } |
2645 | } | |
54a0048b SL |
2646 | |
2647 | impl_marker_for!(BytewiseEquality, | |
2648 | u8 i8 u16 i16 u32 i32 u64 i64 usize isize char bool); | |
3157f602 XL |
2649 | |
2650 | #[doc(hidden)] | |
2651 | unsafe impl<'a, T> TrustedRandomAccess for Iter<'a, T> { | |
2652 | unsafe fn get_unchecked(&mut self, i: usize) -> &'a T { | |
2653 | &*self.ptr.offset(i as isize) | |
2654 | } | |
c30ab7b3 | 2655 | fn may_have_side_effect() -> bool { false } |
3157f602 XL |
2656 | } |
2657 | ||
2658 | #[doc(hidden)] | |
2659 | unsafe impl<'a, T> TrustedRandomAccess for IterMut<'a, T> { | |
2660 | unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut T { | |
2661 | &mut *self.ptr.offset(i as isize) | |
2662 | } | |
c30ab7b3 | 2663 | fn may_have_side_effect() -> bool { false } |
3157f602 | 2664 | } |