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1 | // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
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 | ||
7453a54e SL |
11 | //! A contiguous growable array type with heap-allocated contents, written |
12 | //! `Vec<T>` but pronounced 'vector.' | |
1a4d82fc | 13 | //! |
62682a34 SL |
14 | //! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and |
15 | //! `O(1)` pop (from the end). | |
1a4d82fc JJ |
16 | //! |
17 | //! # Examples | |
18 | //! | |
d9579d0f | 19 | //! You can explicitly create a `Vec<T>` with `new()`: |
1a4d82fc JJ |
20 | //! |
21 | //! ``` | |
d9579d0f | 22 | //! let v: Vec<i32> = Vec::new(); |
1a4d82fc JJ |
23 | //! ``` |
24 | //! | |
d9579d0f | 25 | //! ...or by using the `vec!` macro: |
1a4d82fc JJ |
26 | //! |
27 | //! ``` | |
d9579d0f | 28 | //! let v: Vec<i32> = vec![]; |
1a4d82fc | 29 | //! |
d9579d0f AL |
30 | //! let v = vec![1, 2, 3, 4, 5]; |
31 | //! | |
32 | //! let v = vec![0; 10]; // ten zeroes | |
1a4d82fc JJ |
33 | //! ``` |
34 | //! | |
e9174d1e SL |
35 | //! You can `push` values onto the end of a vector (which will grow the vector |
36 | //! as needed): | |
1a4d82fc JJ |
37 | //! |
38 | //! ``` | |
d9579d0f | 39 | //! let mut v = vec![1, 2]; |
1a4d82fc | 40 | //! |
d9579d0f | 41 | //! v.push(3); |
1a4d82fc JJ |
42 | //! ``` |
43 | //! | |
d9579d0f AL |
44 | //! Popping values works in much the same way: |
45 | //! | |
46 | //! ``` | |
47 | //! let mut v = vec![1, 2]; | |
1a4d82fc | 48 | //! |
d9579d0f | 49 | //! let two = v.pop(); |
1a4d82fc | 50 | //! ``` |
1a4d82fc | 51 | //! |
d9579d0f AL |
52 | //! Vectors also support indexing (through the `Index` and `IndexMut` traits): |
53 | //! | |
54 | //! ``` | |
55 | //! let mut v = vec![1, 2, 3]; | |
56 | //! let three = v[2]; | |
57 | //! v[1] = v[1] + 5; | |
1a4d82fc JJ |
58 | //! ``` |
59 | ||
85aaf69f | 60 | #![stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 61 | |
1a4d82fc | 62 | use alloc::boxed::Box; |
c1a9b12d | 63 | use alloc::heap::EMPTY; |
7453a54e SL |
64 | use alloc::raw_vec::RawVec; |
65 | use borrow::ToOwned; | |
54a0048b | 66 | use borrow::Cow; |
c34b1796 | 67 | use core::cmp::Ordering; |
1a4d82fc JJ |
68 | use core::fmt; |
69 | use core::hash::{self, Hash}; | |
54a0048b | 70 | use core::intrinsics::{arith_offset, assume}; |
c1a9b12d | 71 | use core::iter::FromIterator; |
1a4d82fc | 72 | use core::mem; |
9cc50fc6 | 73 | use core::ops::{Index, IndexMut}; |
1a4d82fc JJ |
74 | use core::ops; |
75 | use core::ptr; | |
85aaf69f | 76 | use core::slice; |
85aaf69f | 77 | |
d9579d0f AL |
78 | use super::range::RangeArgument; |
79 | ||
7453a54e | 80 | /// A contiguous growable array type, written `Vec<T>` but pronounced 'vector.' |
1a4d82fc JJ |
81 | /// |
82 | /// # Examples | |
83 | /// | |
84 | /// ``` | |
85 | /// let mut vec = Vec::new(); | |
85aaf69f SL |
86 | /// vec.push(1); |
87 | /// vec.push(2); | |
1a4d82fc JJ |
88 | /// |
89 | /// assert_eq!(vec.len(), 2); | |
90 | /// assert_eq!(vec[0], 1); | |
91 | /// | |
92 | /// assert_eq!(vec.pop(), Some(2)); | |
93 | /// assert_eq!(vec.len(), 1); | |
94 | /// | |
85aaf69f | 95 | /// vec[0] = 7; |
1a4d82fc JJ |
96 | /// assert_eq!(vec[0], 7); |
97 | /// | |
62682a34 | 98 | /// vec.extend([1, 2, 3].iter().cloned()); |
1a4d82fc | 99 | /// |
62682a34 | 100 | /// for x in &vec { |
1a4d82fc JJ |
101 | /// println!("{}", x); |
102 | /// } | |
c34b1796 | 103 | /// assert_eq!(vec, [7, 1, 2, 3]); |
1a4d82fc JJ |
104 | /// ``` |
105 | /// | |
106 | /// The `vec!` macro is provided to make initialization more convenient: | |
107 | /// | |
108 | /// ``` | |
85aaf69f | 109 | /// let mut vec = vec![1, 2, 3]; |
1a4d82fc | 110 | /// vec.push(4); |
c34b1796 | 111 | /// assert_eq!(vec, [1, 2, 3, 4]); |
1a4d82fc JJ |
112 | /// ``` |
113 | /// | |
c1a9b12d SL |
114 | /// It can also initialize each element of a `Vec<T>` with a given value: |
115 | /// | |
116 | /// ``` | |
117 | /// let vec = vec![0; 5]; | |
118 | /// assert_eq!(vec, [0, 0, 0, 0, 0]); | |
119 | /// ``` | |
120 | /// | |
1a4d82fc JJ |
121 | /// Use a `Vec<T>` as an efficient stack: |
122 | /// | |
123 | /// ``` | |
124 | /// let mut stack = Vec::new(); | |
125 | /// | |
85aaf69f SL |
126 | /// stack.push(1); |
127 | /// stack.push(2); | |
128 | /// stack.push(3); | |
1a4d82fc | 129 | /// |
bd371182 | 130 | /// while let Some(top) = stack.pop() { |
1a4d82fc JJ |
131 | /// // Prints 3, 2, 1 |
132 | /// println!("{}", top); | |
133 | /// } | |
134 | /// ``` | |
135 | /// | |
7453a54e SL |
136 | /// # Indexing |
137 | /// | |
138 | /// The Vec type allows to access values by index, because it implements the | |
139 | /// `Index` trait. An example will be more explicit: | |
140 | /// | |
141 | /// ``` | |
142 | /// let v = vec!(0, 2, 4, 6); | |
143 | /// println!("{}", v[1]); // it will display '2' | |
144 | /// ``` | |
145 | /// | |
146 | /// However be careful: if you try to access an index which isn't in the Vec, | |
147 | /// your software will panic! You cannot do this: | |
148 | /// | |
149 | /// ```ignore | |
150 | /// let v = vec!(0, 2, 4, 6); | |
151 | /// println!("{}", v[6]); // it will panic! | |
152 | /// ``` | |
153 | /// | |
154 | /// In conclusion: always check if the index you want to get really exists | |
155 | /// before doing it. | |
156 | /// | |
157 | /// # Slicing | |
158 | /// | |
159 | /// A Vec can be mutable. Slices, on the other hand, are read-only objects. | |
160 | /// To get a slice, use "&". Example: | |
161 | /// | |
162 | /// ``` | |
163 | /// fn read_slice(slice: &[usize]) { | |
164 | /// // ... | |
165 | /// } | |
166 | /// | |
167 | /// let v = vec!(0, 1); | |
168 | /// read_slice(&v); | |
169 | /// | |
170 | /// // ... and that's all! | |
171 | /// // you can also do it like this: | |
172 | /// let x : &[usize] = &v; | |
173 | /// ``` | |
174 | /// | |
175 | /// In Rust, it's more common to pass slices as arguments rather than vectors | |
176 | /// when you just want to provide a read access. The same goes for String and | |
177 | /// &str. | |
178 | /// | |
1a4d82fc JJ |
179 | /// # Capacity and reallocation |
180 | /// | |
c34b1796 AL |
181 | /// The capacity of a vector is the amount of space allocated for any future |
182 | /// elements that will be added onto the vector. This is not to be confused with | |
183 | /// the *length* of a vector, which specifies the number of actual elements | |
184 | /// within the vector. If a vector's length exceeds its capacity, its capacity | |
185 | /// will automatically be increased, but its elements will have to be | |
1a4d82fc JJ |
186 | /// reallocated. |
187 | /// | |
c34b1796 AL |
188 | /// For example, a vector with capacity 10 and length 0 would be an empty vector |
189 | /// with space for 10 more elements. Pushing 10 or fewer elements onto the | |
190 | /// vector will not change its capacity or cause reallocation to occur. However, | |
191 | /// if the vector's length is increased to 11, it will have to reallocate, which | |
192 | /// can be slow. For this reason, it is recommended to use `Vec::with_capacity` | |
193 | /// whenever possible to specify how big the vector is expected to get. | |
b039eaaf SL |
194 | /// |
195 | /// # Guarantees | |
196 | /// | |
197 | /// Due to its incredibly fundamental nature, Vec makes a lot of guarantees | |
198 | /// about its design. This ensures that it's as low-overhead as possible in | |
199 | /// the general case, and can be correctly manipulated in primitive ways | |
200 | /// by unsafe code. Note that these guarantees refer to an unqualified `Vec<T>`. | |
201 | /// If additional type parameters are added (e.g. to support custom allocators), | |
202 | /// overriding their defaults may change the behavior. | |
203 | /// | |
204 | /// Most fundamentally, Vec is and always will be a (pointer, capacity, length) | |
205 | /// triplet. No more, no less. The order of these fields is completely | |
206 | /// unspecified, and you should use the appropriate methods to modify these. | |
207 | /// The pointer will never be null, so this type is null-pointer-optimized. | |
208 | /// | |
209 | /// However, the pointer may not actually point to allocated memory. In particular, | |
210 | /// if you construct a Vec with capacity 0 via `Vec::new()`, `vec![]`, | |
211 | /// `Vec::with_capacity(0)`, or by calling `shrink_to_fit()` on an empty Vec, it | |
212 | /// will not allocate memory. Similarly, if you store zero-sized types inside | |
213 | /// a Vec, it will not allocate space for them. *Note that in this case the | |
214 | /// Vec may not report a `capacity()` of 0*. Vec will allocate if and only | |
215 | /// if `mem::size_of::<T>() * capacity() > 0`. In general, Vec's allocation | |
216 | /// details are subtle enough that it is strongly recommended that you only | |
217 | /// free memory allocated by a Vec by creating a new Vec and dropping it. | |
218 | /// | |
219 | /// If a Vec *has* allocated memory, then the memory it points to is on the heap | |
220 | /// (as defined by the allocator Rust is configured to use by default), and its | |
221 | /// pointer points to `len()` initialized elements in order (what you would see | |
222 | /// if you coerced it to a slice), followed by `capacity() - len()` logically | |
223 | /// uninitialized elements. | |
224 | /// | |
225 | /// Vec will never perform a "small optimization" where elements are actually | |
226 | /// stored on the stack for two reasons: | |
227 | /// | |
228 | /// * It would make it more difficult for unsafe code to correctly manipulate | |
229 | /// a Vec. The contents of a Vec wouldn't have a stable address if it were | |
230 | /// only moved, and it would be more difficult to determine if a Vec had | |
231 | /// actually allocated memory. | |
232 | /// | |
233 | /// * It would penalize the general case, incurring an additional branch | |
234 | /// on every access. | |
235 | /// | |
236 | /// Vec will never automatically shrink itself, even if completely empty. This | |
237 | /// ensures no unnecessary allocations or deallocations occur. Emptying a Vec | |
238 | /// and then filling it back up to the same `len()` should incur no calls to | |
239 | /// the allocator. If you wish to free up unused memory, use `shrink_to_fit`. | |
240 | /// | |
241 | /// `push` and `insert` will never (re)allocate if the reported capacity is | |
242 | /// sufficient. `push` and `insert` *will* (re)allocate if `len() == capacity()`. | |
243 | /// That is, the reported capacity is completely accurate, and can be relied on. | |
244 | /// It can even be used to manually free the memory allocated by a Vec if | |
245 | /// desired. Bulk insertion methods *may* reallocate, even when not necessary. | |
246 | /// | |
247 | /// Vec does not guarantee any particular growth strategy when reallocating | |
248 | /// when full, nor when `reserve` is called. The current strategy is basic | |
249 | /// and it may prove desirable to use a non-constant growth factor. Whatever | |
250 | /// strategy is used will of course guarantee `O(1)` amortized `push`. | |
251 | /// | |
252 | /// `vec![x; n]`, `vec![a, b, c, d]`, and `Vec::with_capacity(n)`, will all | |
253 | /// produce a Vec with exactly the requested capacity. If `len() == capacity()`, | |
254 | /// (as is the case for the `vec!` macro), then a `Vec<T>` can be converted | |
255 | /// to and from a `Box<[T]>` without reallocating or moving the elements. | |
256 | /// | |
257 | /// Vec will not specifically overwrite any data that is removed from it, | |
258 | /// but also won't specifically preserve it. Its uninitialized memory is | |
259 | /// scratch space that it may use however it wants. It will generally just do | |
260 | /// whatever is most efficient or otherwise easy to implement. Do not rely on | |
261 | /// removed data to be erased for security purposes. Even if you drop a Vec, its | |
262 | /// buffer may simply be reused by another Vec. Even if you zero a Vec's memory | |
263 | /// first, that may not actually happen because the optimizer does not consider | |
264 | /// this a side-effect that must be preserved. | |
265 | /// | |
266 | /// Vec does not currently guarantee the order in which elements are dropped | |
267 | /// (the order has changed in the past, and may change again). | |
268 | /// | |
1a4d82fc | 269 | #[unsafe_no_drop_flag] |
85aaf69f | 270 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 271 | pub struct Vec<T> { |
c1a9b12d | 272 | buf: RawVec<T>, |
85aaf69f | 273 | len: usize, |
1a4d82fc JJ |
274 | } |
275 | ||
1a4d82fc JJ |
276 | //////////////////////////////////////////////////////////////////////////////// |
277 | // Inherent methods | |
278 | //////////////////////////////////////////////////////////////////////////////// | |
279 | ||
280 | impl<T> Vec<T> { | |
281 | /// Constructs a new, empty `Vec<T>`. | |
282 | /// | |
283 | /// The vector will not allocate until elements are pushed onto it. | |
284 | /// | |
285 | /// # Examples | |
286 | /// | |
287 | /// ``` | |
92a42be0 | 288 | /// # #![allow(unused_mut)] |
85aaf69f | 289 | /// let mut vec: Vec<i32> = Vec::new(); |
1a4d82fc JJ |
290 | /// ``` |
291 | #[inline] | |
85aaf69f | 292 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 293 | pub fn new() -> Vec<T> { |
92a42be0 SL |
294 | Vec { |
295 | buf: RawVec::new(), | |
296 | len: 0, | |
297 | } | |
1a4d82fc JJ |
298 | } |
299 | ||
300 | /// Constructs a new, empty `Vec<T>` with the specified capacity. | |
301 | /// | |
e9174d1e SL |
302 | /// The vector will be able to hold exactly `capacity` elements without |
303 | /// reallocating. If `capacity` is 0, the vector will not allocate. | |
1a4d82fc | 304 | /// |
e9174d1e SL |
305 | /// It is important to note that this function does not specify the *length* |
306 | /// of the returned vector, but only the *capacity*. (For an explanation of | |
307 | /// the difference between length and capacity, see the main `Vec<T>` docs | |
308 | /// above, 'Capacity and reallocation'.) | |
1a4d82fc JJ |
309 | /// |
310 | /// # Examples | |
311 | /// | |
312 | /// ``` | |
9346a6ac | 313 | /// let mut vec = Vec::with_capacity(10); |
1a4d82fc JJ |
314 | /// |
315 | /// // The vector contains no items, even though it has capacity for more | |
316 | /// assert_eq!(vec.len(), 0); | |
317 | /// | |
318 | /// // These are all done without reallocating... | |
85aaf69f | 319 | /// for i in 0..10 { |
1a4d82fc JJ |
320 | /// vec.push(i); |
321 | /// } | |
322 | /// | |
323 | /// // ...but this may make the vector reallocate | |
324 | /// vec.push(11); | |
325 | /// ``` | |
326 | #[inline] | |
85aaf69f SL |
327 | #[stable(feature = "rust1", since = "1.0.0")] |
328 | pub fn with_capacity(capacity: usize) -> Vec<T> { | |
92a42be0 SL |
329 | Vec { |
330 | buf: RawVec::with_capacity(capacity), | |
331 | len: 0, | |
332 | } | |
1a4d82fc JJ |
333 | } |
334 | ||
335 | /// Creates a `Vec<T>` directly from the raw components of another vector. | |
336 | /// | |
b039eaaf | 337 | /// # Safety |
c1a9b12d SL |
338 | /// |
339 | /// This is highly unsafe, due to the number of invariants that aren't | |
340 | /// checked: | |
341 | /// | |
342 | /// * `ptr` needs to have been previously allocated via `String`/`Vec<T>` | |
343 | /// (at least, it's highly likely to be incorrect if it wasn't). | |
344 | /// * `length` needs to be the length that less than or equal to `capacity`. | |
345 | /// * `capacity` needs to be the capacity that the pointer was allocated with. | |
346 | /// | |
347 | /// Violating these may cause problems like corrupting the allocator's | |
348 | /// internal datastructures. | |
1a4d82fc JJ |
349 | /// |
350 | /// # Examples | |
351 | /// | |
352 | /// ``` | |
353 | /// use std::ptr; | |
354 | /// use std::mem; | |
355 | /// | |
356 | /// fn main() { | |
85aaf69f | 357 | /// let mut v = vec![1, 2, 3]; |
1a4d82fc JJ |
358 | /// |
359 | /// // Pull out the various important pieces of information about `v` | |
360 | /// let p = v.as_mut_ptr(); | |
361 | /// let len = v.len(); | |
362 | /// let cap = v.capacity(); | |
363 | /// | |
364 | /// unsafe { | |
365 | /// // Cast `v` into the void: no destructor run, so we are in | |
366 | /// // complete control of the allocation to which `p` points. | |
367 | /// mem::forget(v); | |
368 | /// | |
369 | /// // Overwrite memory with 4, 5, 6 | |
85aaf69f | 370 | /// for i in 0..len as isize { |
1a4d82fc JJ |
371 | /// ptr::write(p.offset(i), 4 + i); |
372 | /// } | |
373 | /// | |
374 | /// // Put everything back together into a Vec | |
375 | /// let rebuilt = Vec::from_raw_parts(p, len, cap); | |
c34b1796 | 376 | /// assert_eq!(rebuilt, [4, 5, 6]); |
1a4d82fc JJ |
377 | /// } |
378 | /// } | |
379 | /// ``` | |
85aaf69f | 380 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 | 381 | pub unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Vec<T> { |
85aaf69f | 382 | Vec { |
c1a9b12d | 383 | buf: RawVec::from_raw_parts(ptr, capacity), |
85aaf69f | 384 | len: length, |
85aaf69f | 385 | } |
1a4d82fc JJ |
386 | } |
387 | ||
1a4d82fc JJ |
388 | /// Returns the number of elements the vector can hold without |
389 | /// reallocating. | |
390 | /// | |
391 | /// # Examples | |
392 | /// | |
393 | /// ``` | |
85aaf69f | 394 | /// let vec: Vec<i32> = Vec::with_capacity(10); |
1a4d82fc JJ |
395 | /// assert_eq!(vec.capacity(), 10); |
396 | /// ``` | |
397 | #[inline] | |
85aaf69f SL |
398 | #[stable(feature = "rust1", since = "1.0.0")] |
399 | pub fn capacity(&self) -> usize { | |
c1a9b12d | 400 | self.buf.cap() |
1a4d82fc JJ |
401 | } |
402 | ||
c34b1796 AL |
403 | /// Reserves capacity for at least `additional` more elements to be inserted |
404 | /// in the given `Vec<T>`. The collection may reserve more space to avoid | |
405 | /// frequent reallocations. | |
1a4d82fc JJ |
406 | /// |
407 | /// # Panics | |
408 | /// | |
85aaf69f | 409 | /// Panics if the new capacity overflows `usize`. |
1a4d82fc JJ |
410 | /// |
411 | /// # Examples | |
412 | /// | |
413 | /// ``` | |
85aaf69f | 414 | /// let mut vec = vec![1]; |
1a4d82fc JJ |
415 | /// vec.reserve(10); |
416 | /// assert!(vec.capacity() >= 11); | |
417 | /// ``` | |
85aaf69f SL |
418 | #[stable(feature = "rust1", since = "1.0.0")] |
419 | pub fn reserve(&mut self, additional: usize) { | |
c1a9b12d | 420 | self.buf.reserve(self.len, additional); |
1a4d82fc JJ |
421 | } |
422 | ||
423 | /// Reserves the minimum capacity for exactly `additional` more elements to | |
424 | /// be inserted in the given `Vec<T>`. Does nothing if the capacity is already | |
425 | /// sufficient. | |
426 | /// | |
427 | /// Note that the allocator may give the collection more space than it | |
428 | /// requests. Therefore capacity can not be relied upon to be precisely | |
429 | /// minimal. Prefer `reserve` if future insertions are expected. | |
430 | /// | |
431 | /// # Panics | |
432 | /// | |
85aaf69f | 433 | /// Panics if the new capacity overflows `usize`. |
1a4d82fc JJ |
434 | /// |
435 | /// # Examples | |
436 | /// | |
437 | /// ``` | |
85aaf69f | 438 | /// let mut vec = vec![1]; |
1a4d82fc JJ |
439 | /// vec.reserve_exact(10); |
440 | /// assert!(vec.capacity() >= 11); | |
441 | /// ``` | |
85aaf69f SL |
442 | #[stable(feature = "rust1", since = "1.0.0")] |
443 | pub fn reserve_exact(&mut self, additional: usize) { | |
c1a9b12d | 444 | self.buf.reserve_exact(self.len, additional); |
1a4d82fc JJ |
445 | } |
446 | ||
447 | /// Shrinks the capacity of the vector as much as possible. | |
448 | /// | |
449 | /// It will drop down as close as possible to the length but the allocator | |
450 | /// may still inform the vector that there is space for a few more elements. | |
451 | /// | |
452 | /// # Examples | |
453 | /// | |
454 | /// ``` | |
85aaf69f | 455 | /// let mut vec = Vec::with_capacity(10); |
62682a34 | 456 | /// vec.extend([1, 2, 3].iter().cloned()); |
1a4d82fc JJ |
457 | /// assert_eq!(vec.capacity(), 10); |
458 | /// vec.shrink_to_fit(); | |
459 | /// assert!(vec.capacity() >= 3); | |
460 | /// ``` | |
85aaf69f | 461 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 462 | pub fn shrink_to_fit(&mut self) { |
c1a9b12d | 463 | self.buf.shrink_to_fit(self.len); |
1a4d82fc JJ |
464 | } |
465 | ||
9346a6ac | 466 | /// Converts the vector into Box<[T]>. |
1a4d82fc JJ |
467 | /// |
468 | /// Note that this will drop any excess capacity. Calling this and | |
469 | /// converting back to a vector with `into_vec()` is equivalent to calling | |
470 | /// `shrink_to_fit()`. | |
c34b1796 | 471 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 472 | pub fn into_boxed_slice(mut self) -> Box<[T]> { |
1a4d82fc | 473 | unsafe { |
c1a9b12d SL |
474 | self.shrink_to_fit(); |
475 | let buf = ptr::read(&self.buf); | |
1a4d82fc | 476 | mem::forget(self); |
c1a9b12d | 477 | buf.into_box() |
1a4d82fc JJ |
478 | } |
479 | } | |
480 | ||
92a42be0 | 481 | /// Shorten a vector to be `len` elements long, dropping excess elements. |
1a4d82fc JJ |
482 | /// |
483 | /// If `len` is greater than the vector's current length, this has no | |
484 | /// effect. | |
485 | /// | |
486 | /// # Examples | |
487 | /// | |
488 | /// ``` | |
92a42be0 | 489 | /// let mut vec = vec![1, 2, 3, 4, 5]; |
1a4d82fc | 490 | /// vec.truncate(2); |
c34b1796 | 491 | /// assert_eq!(vec, [1, 2]); |
1a4d82fc | 492 | /// ``` |
85aaf69f SL |
493 | #[stable(feature = "rust1", since = "1.0.0")] |
494 | pub fn truncate(&mut self, len: usize) { | |
1a4d82fc JJ |
495 | unsafe { |
496 | // drop any extra elements | |
497 | while len < self.len { | |
54a0048b SL |
498 | // decrement len before the drop_in_place(), so a panic on Drop |
499 | // doesn't re-drop the just-failed value. | |
1a4d82fc | 500 | self.len -= 1; |
54a0048b SL |
501 | let len = self.len; |
502 | ptr::drop_in_place(self.get_unchecked_mut(len)); | |
1a4d82fc JJ |
503 | } |
504 | } | |
505 | } | |
506 | ||
9346a6ac | 507 | /// Extracts a slice containing the entire vector. |
62682a34 SL |
508 | /// |
509 | /// Equivalent to `&s[..]`. | |
1a4d82fc | 510 | #[inline] |
9cc50fc6 | 511 | #[stable(feature = "vec_as_slice", since = "1.7.0")] |
c34b1796 AL |
512 | pub fn as_slice(&self) -> &[T] { |
513 | self | |
514 | } | |
515 | ||
62682a34 SL |
516 | /// Extracts a mutable slice of the entire vector. |
517 | /// | |
518 | /// Equivalent to `&mut s[..]`. | |
c34b1796 | 519 | #[inline] |
9cc50fc6 | 520 | #[stable(feature = "vec_as_slice", since = "1.7.0")] |
85aaf69f | 521 | pub fn as_mut_slice(&mut self) -> &mut [T] { |
c34b1796 | 522 | &mut self[..] |
1a4d82fc JJ |
523 | } |
524 | ||
1a4d82fc JJ |
525 | /// Sets the length of a vector. |
526 | /// | |
527 | /// This will explicitly set the size of the vector, without actually | |
528 | /// modifying its buffers, so it is up to the caller to ensure that the | |
529 | /// vector is actually the specified size. | |
530 | /// | |
531 | /// # Examples | |
532 | /// | |
533 | /// ``` | |
85aaf69f | 534 | /// let mut v = vec![1, 2, 3, 4]; |
1a4d82fc JJ |
535 | /// unsafe { |
536 | /// v.set_len(1); | |
537 | /// } | |
538 | /// ``` | |
539 | #[inline] | |
85aaf69f SL |
540 | #[stable(feature = "rust1", since = "1.0.0")] |
541 | pub unsafe fn set_len(&mut self, len: usize) { | |
1a4d82fc JJ |
542 | self.len = len; |
543 | } | |
544 | ||
545 | /// Removes an element from anywhere in the vector and return it, replacing | |
546 | /// it with the last element. | |
547 | /// | |
548 | /// This does not preserve ordering, but is O(1). | |
549 | /// | |
550 | /// # Panics | |
551 | /// | |
552 | /// Panics if `index` is out of bounds. | |
553 | /// | |
554 | /// # Examples | |
555 | /// | |
556 | /// ``` | |
557 | /// let mut v = vec!["foo", "bar", "baz", "qux"]; | |
558 | /// | |
559 | /// assert_eq!(v.swap_remove(1), "bar"); | |
c34b1796 | 560 | /// assert_eq!(v, ["foo", "qux", "baz"]); |
1a4d82fc JJ |
561 | /// |
562 | /// assert_eq!(v.swap_remove(0), "foo"); | |
c34b1796 | 563 | /// assert_eq!(v, ["baz", "qux"]); |
1a4d82fc JJ |
564 | /// ``` |
565 | #[inline] | |
85aaf69f SL |
566 | #[stable(feature = "rust1", since = "1.0.0")] |
567 | pub fn swap_remove(&mut self, index: usize) -> T { | |
1a4d82fc JJ |
568 | let length = self.len(); |
569 | self.swap(index, length - 1); | |
570 | self.pop().unwrap() | |
571 | } | |
572 | ||
573 | /// Inserts an element at position `index` within the vector, shifting all | |
7453a54e | 574 | /// elements after it to the right. |
1a4d82fc JJ |
575 | /// |
576 | /// # Panics | |
577 | /// | |
9346a6ac | 578 | /// Panics if `index` is greater than the vector's length. |
1a4d82fc JJ |
579 | /// |
580 | /// # Examples | |
581 | /// | |
582 | /// ``` | |
85aaf69f | 583 | /// let mut vec = vec![1, 2, 3]; |
1a4d82fc | 584 | /// vec.insert(1, 4); |
c34b1796 | 585 | /// assert_eq!(vec, [1, 4, 2, 3]); |
1a4d82fc | 586 | /// vec.insert(4, 5); |
c34b1796 | 587 | /// assert_eq!(vec, [1, 4, 2, 3, 5]); |
1a4d82fc | 588 | /// ``` |
85aaf69f SL |
589 | #[stable(feature = "rust1", since = "1.0.0")] |
590 | pub fn insert(&mut self, index: usize, element: T) { | |
1a4d82fc JJ |
591 | let len = self.len(); |
592 | assert!(index <= len); | |
c1a9b12d | 593 | |
1a4d82fc | 594 | // space for the new element |
92a42be0 SL |
595 | if len == self.buf.cap() { |
596 | self.buf.double(); | |
597 | } | |
1a4d82fc | 598 | |
92a42be0 SL |
599 | unsafe { |
600 | // infallible | |
1a4d82fc JJ |
601 | // The spot to put the new value |
602 | { | |
85aaf69f | 603 | let p = self.as_mut_ptr().offset(index as isize); |
1a4d82fc JJ |
604 | // Shift everything over to make space. (Duplicating the |
605 | // `index`th element into two consecutive places.) | |
c1a9b12d | 606 | ptr::copy(p, p.offset(1), len - index); |
1a4d82fc JJ |
607 | // Write it in, overwriting the first copy of the `index`th |
608 | // element. | |
c1a9b12d | 609 | ptr::write(p, element); |
1a4d82fc JJ |
610 | } |
611 | self.set_len(len + 1); | |
612 | } | |
613 | } | |
614 | ||
615 | /// Removes and returns the element at position `index` within the vector, | |
7453a54e | 616 | /// shifting all elements after it to the left. |
1a4d82fc JJ |
617 | /// |
618 | /// # Panics | |
619 | /// | |
bd371182 | 620 | /// Panics if `index` is out of bounds. |
1a4d82fc JJ |
621 | /// |
622 | /// # Examples | |
623 | /// | |
624 | /// ``` | |
85aaf69f | 625 | /// let mut v = vec![1, 2, 3]; |
1a4d82fc | 626 | /// assert_eq!(v.remove(1), 2); |
c34b1796 | 627 | /// assert_eq!(v, [1, 3]); |
1a4d82fc | 628 | /// ``` |
85aaf69f SL |
629 | #[stable(feature = "rust1", since = "1.0.0")] |
630 | pub fn remove(&mut self, index: usize) -> T { | |
1a4d82fc JJ |
631 | let len = self.len(); |
632 | assert!(index < len); | |
92a42be0 SL |
633 | unsafe { |
634 | // infallible | |
1a4d82fc JJ |
635 | let ret; |
636 | { | |
637 | // the place we are taking from. | |
85aaf69f | 638 | let ptr = self.as_mut_ptr().offset(index as isize); |
1a4d82fc JJ |
639 | // copy it out, unsafely having a copy of the value on |
640 | // the stack and in the vector at the same time. | |
85aaf69f | 641 | ret = ptr::read(ptr); |
1a4d82fc JJ |
642 | |
643 | // Shift everything down to fill in that spot. | |
c1a9b12d | 644 | ptr::copy(ptr.offset(1), ptr, len - index - 1); |
1a4d82fc JJ |
645 | } |
646 | self.set_len(len - 1); | |
647 | ret | |
648 | } | |
649 | } | |
650 | ||
651 | /// Retains only the elements specified by the predicate. | |
652 | /// | |
653 | /// In other words, remove all elements `e` such that `f(&e)` returns false. | |
654 | /// This method operates in place and preserves the order of the retained | |
655 | /// elements. | |
656 | /// | |
657 | /// # Examples | |
658 | /// | |
659 | /// ``` | |
85aaf69f | 660 | /// let mut vec = vec![1, 2, 3, 4]; |
1a4d82fc | 661 | /// vec.retain(|&x| x%2 == 0); |
c34b1796 | 662 | /// assert_eq!(vec, [2, 4]); |
1a4d82fc | 663 | /// ``` |
85aaf69f | 664 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 SL |
665 | pub fn retain<F>(&mut self, mut f: F) |
666 | where F: FnMut(&T) -> bool | |
667 | { | |
1a4d82fc | 668 | let len = self.len(); |
85aaf69f | 669 | let mut del = 0; |
1a4d82fc | 670 | { |
85aaf69f | 671 | let v = &mut **self; |
1a4d82fc | 672 | |
85aaf69f | 673 | for i in 0..len { |
1a4d82fc JJ |
674 | if !f(&v[i]) { |
675 | del += 1; | |
676 | } else if del > 0 { | |
92a42be0 | 677 | v.swap(i - del, i); |
1a4d82fc JJ |
678 | } |
679 | } | |
680 | } | |
681 | if del > 0 { | |
682 | self.truncate(len - del); | |
683 | } | |
684 | } | |
685 | ||
686 | /// Appends an element to the back of a collection. | |
687 | /// | |
688 | /// # Panics | |
689 | /// | |
85aaf69f | 690 | /// Panics if the number of elements in the vector overflows a `usize`. |
1a4d82fc JJ |
691 | /// |
692 | /// # Examples | |
693 | /// | |
c34b1796 | 694 | /// ``` |
c1a9b12d | 695 | /// let mut vec = vec![1, 2]; |
1a4d82fc | 696 | /// vec.push(3); |
c34b1796 | 697 | /// assert_eq!(vec, [1, 2, 3]); |
1a4d82fc JJ |
698 | /// ``` |
699 | #[inline] | |
85aaf69f | 700 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 701 | pub fn push(&mut self, value: T) { |
c1a9b12d SL |
702 | // This will panic or abort if we would allocate > isize::MAX bytes |
703 | // or if the length increment would overflow for zero-sized types. | |
92a42be0 SL |
704 | if self.len == self.buf.cap() { |
705 | self.buf.double(); | |
706 | } | |
1a4d82fc | 707 | unsafe { |
c1a9b12d SL |
708 | let end = self.as_mut_ptr().offset(self.len as isize); |
709 | ptr::write(end, value); | |
1a4d82fc JJ |
710 | self.len += 1; |
711 | } | |
712 | } | |
713 | ||
e9174d1e SL |
714 | /// Removes the last element from a vector and returns it, or `None` if it |
715 | /// is empty. | |
1a4d82fc JJ |
716 | /// |
717 | /// # Examples | |
718 | /// | |
c34b1796 | 719 | /// ``` |
85aaf69f | 720 | /// let mut vec = vec![1, 2, 3]; |
1a4d82fc | 721 | /// assert_eq!(vec.pop(), Some(3)); |
c34b1796 | 722 | /// assert_eq!(vec, [1, 2]); |
1a4d82fc JJ |
723 | /// ``` |
724 | #[inline] | |
85aaf69f | 725 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
726 | pub fn pop(&mut self) -> Option<T> { |
727 | if self.len == 0 { | |
728 | None | |
729 | } else { | |
730 | unsafe { | |
731 | self.len -= 1; | |
732 | Some(ptr::read(self.get_unchecked(self.len()))) | |
733 | } | |
734 | } | |
735 | } | |
736 | ||
85aaf69f SL |
737 | /// Moves all the elements of `other` into `Self`, leaving `other` empty. |
738 | /// | |
739 | /// # Panics | |
740 | /// | |
741 | /// Panics if the number of elements in the vector overflows a `usize`. | |
742 | /// | |
743 | /// # Examples | |
744 | /// | |
745 | /// ``` | |
746 | /// let mut vec = vec![1, 2, 3]; | |
747 | /// let mut vec2 = vec![4, 5, 6]; | |
748 | /// vec.append(&mut vec2); | |
c34b1796 AL |
749 | /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]); |
750 | /// assert_eq!(vec2, []); | |
85aaf69f SL |
751 | /// ``` |
752 | #[inline] | |
e9174d1e | 753 | #[stable(feature = "append", since = "1.4.0")] |
85aaf69f | 754 | pub fn append(&mut self, other: &mut Self) { |
85aaf69f SL |
755 | self.reserve(other.len()); |
756 | let len = self.len(); | |
757 | unsafe { | |
92a42be0 | 758 | ptr::copy_nonoverlapping(other.as_ptr(), self.get_unchecked_mut(len), other.len()); |
85aaf69f SL |
759 | } |
760 | ||
761 | self.len += other.len(); | |
92a42be0 SL |
762 | unsafe { |
763 | other.set_len(0); | |
764 | } | |
85aaf69f SL |
765 | } |
766 | ||
d9579d0f | 767 | /// Create a draining iterator that removes the specified range in the vector |
9cc50fc6 | 768 | /// and yields the removed items. |
d9579d0f | 769 | /// |
9cc50fc6 SL |
770 | /// Note 1: The element range is removed even if the iterator is not |
771 | /// consumed until the end. | |
772 | /// | |
773 | /// Note 2: It is unspecified how many elements are removed from the vector, | |
d9579d0f AL |
774 | /// if the `Drain` value is leaked. |
775 | /// | |
776 | /// # Panics | |
777 | /// | |
778 | /// Panics if the starting point is greater than the end point or if | |
779 | /// the end point is greater than the length of the vector. | |
1a4d82fc JJ |
780 | /// |
781 | /// # Examples | |
782 | /// | |
783 | /// ``` | |
d9579d0f | 784 | /// let mut v = vec![1, 2, 3]; |
9cc50fc6 SL |
785 | /// let u: Vec<_> = v.drain(1..).collect(); |
786 | /// assert_eq!(v, &[1]); | |
787 | /// assert_eq!(u, &[2, 3]); | |
788 | /// | |
789 | /// // A full range clears the vector | |
790 | /// v.drain(..); | |
d9579d0f | 791 | /// assert_eq!(v, &[]); |
1a4d82fc | 792 | /// ``` |
92a42be0 SL |
793 | #[stable(feature = "drain", since = "1.6.0")] |
794 | pub fn drain<R>(&mut self, range: R) -> Drain<T> | |
795 | where R: RangeArgument<usize> | |
796 | { | |
d9579d0f AL |
797 | // Memory safety |
798 | // | |
799 | // When the Drain is first created, it shortens the length of | |
800 | // the source vector to make sure no uninitalized or moved-from elements | |
801 | // are accessible at all if the Drain's destructor never gets to run. | |
802 | // | |
803 | // Drain will ptr::read out the values to remove. | |
804 | // When finished, remaining tail of the vec is copied back to cover | |
805 | // the hole, and the vector length is restored to the new length. | |
806 | // | |
807 | let len = self.len(); | |
808 | let start = *range.start().unwrap_or(&0); | |
809 | let end = *range.end().unwrap_or(&len); | |
810 | assert!(start <= end); | |
811 | assert!(end <= len); | |
812 | ||
1a4d82fc | 813 | unsafe { |
d9579d0f AL |
814 | // set self.vec length's to start, to be safe in case Drain is leaked |
815 | self.set_len(start); | |
816 | // Use the borrow in the IterMut to indicate borrowing behavior of the | |
817 | // whole Drain iterator (like &mut T). | |
92a42be0 SL |
818 | let range_slice = slice::from_raw_parts_mut(self.as_mut_ptr().offset(start as isize), |
819 | end - start); | |
1a4d82fc | 820 | Drain { |
d9579d0f AL |
821 | tail_start: end, |
822 | tail_len: len - end, | |
823 | iter: range_slice.iter_mut(), | |
824 | vec: self as *mut _, | |
1a4d82fc JJ |
825 | } |
826 | } | |
827 | } | |
828 | ||
829 | /// Clears the vector, removing all values. | |
830 | /// | |
831 | /// # Examples | |
832 | /// | |
833 | /// ``` | |
85aaf69f | 834 | /// let mut v = vec![1, 2, 3]; |
1a4d82fc JJ |
835 | /// |
836 | /// v.clear(); | |
837 | /// | |
838 | /// assert!(v.is_empty()); | |
839 | /// ``` | |
840 | #[inline] | |
85aaf69f | 841 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
842 | pub fn clear(&mut self) { |
843 | self.truncate(0) | |
844 | } | |
845 | ||
846 | /// Returns the number of elements in the vector. | |
847 | /// | |
848 | /// # Examples | |
849 | /// | |
850 | /// ``` | |
85aaf69f | 851 | /// let a = vec![1, 2, 3]; |
1a4d82fc JJ |
852 | /// assert_eq!(a.len(), 3); |
853 | /// ``` | |
854 | #[inline] | |
85aaf69f | 855 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 SL |
856 | pub fn len(&self) -> usize { |
857 | self.len | |
858 | } | |
1a4d82fc JJ |
859 | |
860 | /// Returns `true` if the vector contains no elements. | |
861 | /// | |
862 | /// # Examples | |
863 | /// | |
864 | /// ``` | |
865 | /// let mut v = Vec::new(); | |
866 | /// assert!(v.is_empty()); | |
867 | /// | |
85aaf69f | 868 | /// v.push(1); |
1a4d82fc JJ |
869 | /// assert!(!v.is_empty()); |
870 | /// ``` | |
85aaf69f | 871 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 SL |
872 | pub fn is_empty(&self) -> bool { |
873 | self.len() == 0 | |
874 | } | |
1a4d82fc | 875 | |
85aaf69f SL |
876 | /// Splits the collection into two at the given index. |
877 | /// | |
878 | /// Returns a newly allocated `Self`. `self` contains elements `[0, at)`, | |
879 | /// and the returned `Self` contains elements `[at, len)`. | |
880 | /// | |
881 | /// Note that the capacity of `self` does not change. | |
882 | /// | |
883 | /// # Panics | |
884 | /// | |
885 | /// Panics if `at > len`. | |
886 | /// | |
887 | /// # Examples | |
888 | /// | |
889 | /// ``` | |
890 | /// let mut vec = vec![1,2,3]; | |
891 | /// let vec2 = vec.split_off(1); | |
c34b1796 AL |
892 | /// assert_eq!(vec, [1]); |
893 | /// assert_eq!(vec2, [2, 3]); | |
85aaf69f SL |
894 | /// ``` |
895 | #[inline] | |
e9174d1e | 896 | #[stable(feature = "split_off", since = "1.4.0")] |
85aaf69f SL |
897 | pub fn split_off(&mut self, at: usize) -> Self { |
898 | assert!(at <= self.len(), "`at` out of bounds"); | |
899 | ||
900 | let other_len = self.len - at; | |
901 | let mut other = Vec::with_capacity(other_len); | |
902 | ||
903 | // Unsafely `set_len` and copy items to `other`. | |
904 | unsafe { | |
905 | self.set_len(at); | |
906 | other.set_len(other_len); | |
907 | ||
92a42be0 SL |
908 | ptr::copy_nonoverlapping(self.as_ptr().offset(at as isize), |
909 | other.as_mut_ptr(), | |
910 | other.len()); | |
85aaf69f SL |
911 | } |
912 | other | |
913 | } | |
1a4d82fc JJ |
914 | } |
915 | ||
916 | impl<T: Clone> Vec<T> { | |
917 | /// Resizes the `Vec` in-place so that `len()` is equal to `new_len`. | |
918 | /// | |
92a42be0 SL |
919 | /// If `new_len` is greater than `len()`, the `Vec` is extended by the |
920 | /// difference, with each additional slot filled with `value`. | |
921 | /// If `new_len` is less than `len()`, the `Vec` is simply truncated. | |
1a4d82fc JJ |
922 | /// |
923 | /// # Examples | |
924 | /// | |
925 | /// ``` | |
926 | /// let mut vec = vec!["hello"]; | |
927 | /// vec.resize(3, "world"); | |
c34b1796 | 928 | /// assert_eq!(vec, ["hello", "world", "world"]); |
1a4d82fc | 929 | /// |
85aaf69f | 930 | /// let mut vec = vec![1, 2, 3, 4]; |
1a4d82fc | 931 | /// vec.resize(2, 0); |
c34b1796 | 932 | /// assert_eq!(vec, [1, 2]); |
1a4d82fc | 933 | /// ``` |
b039eaaf | 934 | #[stable(feature = "vec_resize", since = "1.5.0")] |
85aaf69f | 935 | pub fn resize(&mut self, new_len: usize, value: T) { |
1a4d82fc JJ |
936 | let len = self.len(); |
937 | ||
938 | if new_len > len { | |
c1a9b12d | 939 | self.extend_with_element(new_len - len, value); |
1a4d82fc JJ |
940 | } else { |
941 | self.truncate(new_len); | |
942 | } | |
943 | } | |
944 | ||
c1a9b12d SL |
945 | /// Extend the vector by `n` additional clones of `value`. |
946 | fn extend_with_element(&mut self, n: usize, value: T) { | |
947 | self.reserve(n); | |
948 | ||
949 | unsafe { | |
950 | let len = self.len(); | |
951 | let mut ptr = self.as_mut_ptr().offset(len as isize); | |
952 | // Write all elements except the last one | |
953 | for i in 1..n { | |
954 | ptr::write(ptr, value.clone()); | |
955 | ptr = ptr.offset(1); | |
956 | // Increment the length in every step in case clone() panics | |
957 | self.set_len(len + i); | |
958 | } | |
959 | ||
960 | if n > 0 { | |
961 | // We can write the last element directly without cloning needlessly | |
962 | ptr::write(ptr, value); | |
963 | self.set_len(len + n); | |
964 | } | |
965 | } | |
966 | } | |
967 | ||
1a4d82fc JJ |
968 | /// Appends all elements in a slice to the `Vec`. |
969 | /// | |
970 | /// Iterates over the slice `other`, clones each element, and then appends | |
971 | /// it to this `Vec`. The `other` vector is traversed in-order. | |
972 | /// | |
92a42be0 SL |
973 | /// Note that this function is same as `extend` except that it is |
974 | /// specialized to work with slices instead. If and when Rust gets | |
975 | /// specialization this function will likely be deprecated (but still | |
976 | /// available). | |
977 | /// | |
1a4d82fc JJ |
978 | /// # Examples |
979 | /// | |
980 | /// ``` | |
85aaf69f | 981 | /// let mut vec = vec![1]; |
92a42be0 | 982 | /// vec.extend_from_slice(&[2, 3, 4]); |
c34b1796 | 983 | /// assert_eq!(vec, [1, 2, 3, 4]); |
1a4d82fc | 984 | /// ``` |
92a42be0 SL |
985 | #[stable(feature = "vec_extend_from_slice", since = "1.6.0")] |
986 | pub fn extend_from_slice(&mut self, other: &[T]) { | |
1a4d82fc JJ |
987 | self.reserve(other.len()); |
988 | ||
85aaf69f | 989 | for i in 0..other.len() { |
1a4d82fc JJ |
990 | let len = self.len(); |
991 | ||
e9174d1e SL |
992 | // Unsafe code so this can be optimised to a memcpy (or something |
993 | // similarly fast) when T is Copy. LLVM is easily confused, so any | |
994 | // extra operations during the loop can prevent this optimisation. | |
1a4d82fc | 995 | unsafe { |
92a42be0 | 996 | ptr::write(self.get_unchecked_mut(len), other.get_unchecked(i).clone()); |
1a4d82fc JJ |
997 | self.set_len(len + 1); |
998 | } | |
999 | } | |
1000 | } | |
1001 | } | |
1002 | ||
1003 | impl<T: PartialEq> Vec<T> { | |
1004 | /// Removes consecutive repeated elements in the vector. | |
1005 | /// | |
1006 | /// If the vector is sorted, this removes all duplicates. | |
1007 | /// | |
1008 | /// # Examples | |
1009 | /// | |
1010 | /// ``` | |
85aaf69f | 1011 | /// let mut vec = vec![1, 2, 2, 3, 2]; |
1a4d82fc JJ |
1012 | /// |
1013 | /// vec.dedup(); | |
1014 | /// | |
c34b1796 | 1015 | /// assert_eq!(vec, [1, 2, 3, 2]); |
1a4d82fc | 1016 | /// ``` |
85aaf69f | 1017 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1018 | pub fn dedup(&mut self) { |
1019 | unsafe { | |
1020 | // Although we have a mutable reference to `self`, we cannot make | |
1021 | // *arbitrary* changes. The `PartialEq` comparisons could panic, so we | |
1022 | // must ensure that the vector is in a valid state at all time. | |
1023 | // | |
1024 | // The way that we handle this is by using swaps; we iterate | |
1025 | // over all the elements, swapping as we go so that at the end | |
1026 | // the elements we wish to keep are in the front, and those we | |
1027 | // wish to reject are at the back. We can then truncate the | |
1028 | // vector. This operation is still O(n). | |
1029 | // | |
1030 | // Example: We start in this state, where `r` represents "next | |
1031 | // read" and `w` represents "next_write`. | |
1032 | // | |
1033 | // r | |
1034 | // +---+---+---+---+---+---+ | |
1035 | // | 0 | 1 | 1 | 2 | 3 | 3 | | |
1036 | // +---+---+---+---+---+---+ | |
1037 | // w | |
1038 | // | |
1039 | // Comparing self[r] against self[w-1], this is not a duplicate, so | |
1040 | // we swap self[r] and self[w] (no effect as r==w) and then increment both | |
1041 | // r and w, leaving us with: | |
1042 | // | |
1043 | // r | |
1044 | // +---+---+---+---+---+---+ | |
1045 | // | 0 | 1 | 1 | 2 | 3 | 3 | | |
1046 | // +---+---+---+---+---+---+ | |
1047 | // w | |
1048 | // | |
1049 | // Comparing self[r] against self[w-1], this value is a duplicate, | |
1050 | // so we increment `r` but leave everything else unchanged: | |
1051 | // | |
1052 | // r | |
1053 | // +---+---+---+---+---+---+ | |
1054 | // | 0 | 1 | 1 | 2 | 3 | 3 | | |
1055 | // +---+---+---+---+---+---+ | |
1056 | // w | |
1057 | // | |
1058 | // Comparing self[r] against self[w-1], this is not a duplicate, | |
1059 | // so swap self[r] and self[w] and advance r and w: | |
1060 | // | |
1061 | // r | |
1062 | // +---+---+---+---+---+---+ | |
1063 | // | 0 | 1 | 2 | 1 | 3 | 3 | | |
1064 | // +---+---+---+---+---+---+ | |
1065 | // w | |
1066 | // | |
1067 | // Not a duplicate, repeat: | |
1068 | // | |
1069 | // r | |
1070 | // +---+---+---+---+---+---+ | |
1071 | // | 0 | 1 | 2 | 3 | 1 | 3 | | |
1072 | // +---+---+---+---+---+---+ | |
1073 | // w | |
1074 | // | |
1075 | // Duplicate, advance r. End of vec. Truncate to w. | |
1076 | ||
1077 | let ln = self.len(); | |
92a42be0 SL |
1078 | if ln <= 1 { |
1079 | return; | |
1080 | } | |
1a4d82fc | 1081 | |
62682a34 | 1082 | // Avoid bounds checks by using raw pointers. |
1a4d82fc | 1083 | let p = self.as_mut_ptr(); |
c34b1796 AL |
1084 | let mut r: usize = 1; |
1085 | let mut w: usize = 1; | |
1a4d82fc JJ |
1086 | |
1087 | while r < ln { | |
85aaf69f SL |
1088 | let p_r = p.offset(r as isize); |
1089 | let p_wm1 = p.offset((w - 1) as isize); | |
1a4d82fc JJ |
1090 | if *p_r != *p_wm1 { |
1091 | if r != w { | |
1092 | let p_w = p_wm1.offset(1); | |
1093 | mem::swap(&mut *p_r, &mut *p_w); | |
1094 | } | |
1095 | w += 1; | |
1096 | } | |
1097 | r += 1; | |
1098 | } | |
1099 | ||
1100 | self.truncate(w); | |
1101 | } | |
1102 | } | |
1103 | } | |
1104 | ||
1105 | //////////////////////////////////////////////////////////////////////////////// | |
1106 | // Internal methods and functions | |
1107 | //////////////////////////////////////////////////////////////////////////////// | |
1108 | ||
85aaf69f SL |
1109 | #[doc(hidden)] |
1110 | #[stable(feature = "rust1", since = "1.0.0")] | |
1111 | pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> { | |
c1a9b12d SL |
1112 | let mut v = Vec::with_capacity(n); |
1113 | v.extend_with_element(n, elem); | |
1114 | v | |
85aaf69f SL |
1115 | } |
1116 | ||
1a4d82fc JJ |
1117 | //////////////////////////////////////////////////////////////////////////////// |
1118 | // Common trait implementations for Vec | |
1119 | //////////////////////////////////////////////////////////////////////////////// | |
1120 | ||
bd371182 | 1121 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 | 1122 | impl<T: Clone> Clone for Vec<T> { |
c34b1796 | 1123 | #[cfg(not(test))] |
92a42be0 SL |
1124 | fn clone(&self) -> Vec<T> { |
1125 | <[T]>::to_vec(&**self) | |
1126 | } | |
c34b1796 AL |
1127 | |
1128 | // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is | |
1129 | // required for this method definition, is not available. Instead use the | |
1130 | // `slice::to_vec` function which is only available with cfg(test) | |
1131 | // NB see the slice::hack module in slice.rs for more information | |
1132 | #[cfg(test)] | |
1133 | fn clone(&self) -> Vec<T> { | |
1134 | ::slice::to_vec(&**self) | |
1135 | } | |
1a4d82fc JJ |
1136 | |
1137 | fn clone_from(&mut self, other: &Vec<T>) { | |
1138 | // drop anything in self that will not be overwritten | |
b039eaaf SL |
1139 | self.truncate(other.len()); |
1140 | let len = self.len(); | |
1a4d82fc JJ |
1141 | |
1142 | // reuse the contained values' allocations/resources. | |
b039eaaf | 1143 | self.clone_from_slice(&other[..len]); |
1a4d82fc JJ |
1144 | |
1145 | // self.len <= other.len due to the truncate above, so the | |
1146 | // slice here is always in-bounds. | |
92a42be0 | 1147 | self.extend_from_slice(&other[len..]); |
1a4d82fc JJ |
1148 | } |
1149 | } | |
1150 | ||
85aaf69f | 1151 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1152 | impl<T: Hash> Hash for Vec<T> { |
1a4d82fc | 1153 | #[inline] |
85aaf69f SL |
1154 | fn hash<H: hash::Hasher>(&self, state: &mut H) { |
1155 | Hash::hash(&**self, state) | |
1a4d82fc JJ |
1156 | } |
1157 | } | |
1158 | ||
85aaf69f SL |
1159 | #[stable(feature = "rust1", since = "1.0.0")] |
1160 | impl<T> Index<usize> for Vec<T> { | |
1a4d82fc JJ |
1161 | type Output = T; |
1162 | ||
1163 | #[inline] | |
c34b1796 | 1164 | fn index(&self, index: usize) -> &T { |
85aaf69f | 1165 | // NB built-in indexing via `&[T]` |
c34b1796 | 1166 | &(**self)[index] |
1a4d82fc JJ |
1167 | } |
1168 | } | |
1169 | ||
85aaf69f SL |
1170 | #[stable(feature = "rust1", since = "1.0.0")] |
1171 | impl<T> IndexMut<usize> for Vec<T> { | |
1a4d82fc | 1172 | #[inline] |
c34b1796 | 1173 | fn index_mut(&mut self, index: usize) -> &mut T { |
85aaf69f | 1174 | // NB built-in indexing via `&mut [T]` |
c34b1796 | 1175 | &mut (**self)[index] |
1a4d82fc JJ |
1176 | } |
1177 | } | |
1178 | ||
1179 | ||
85aaf69f SL |
1180 | #[stable(feature = "rust1", since = "1.0.0")] |
1181 | impl<T> ops::Index<ops::Range<usize>> for Vec<T> { | |
1a4d82fc | 1182 | type Output = [T]; |
c34b1796 | 1183 | |
1a4d82fc | 1184 | #[inline] |
c34b1796 | 1185 | fn index(&self, index: ops::Range<usize>) -> &[T] { |
85aaf69f | 1186 | Index::index(&**self, index) |
1a4d82fc JJ |
1187 | } |
1188 | } | |
85aaf69f SL |
1189 | #[stable(feature = "rust1", since = "1.0.0")] |
1190 | impl<T> ops::Index<ops::RangeTo<usize>> for Vec<T> { | |
1a4d82fc | 1191 | type Output = [T]; |
c34b1796 | 1192 | |
1a4d82fc | 1193 | #[inline] |
c34b1796 | 1194 | fn index(&self, index: ops::RangeTo<usize>) -> &[T] { |
85aaf69f | 1195 | Index::index(&**self, index) |
1a4d82fc JJ |
1196 | } |
1197 | } | |
85aaf69f SL |
1198 | #[stable(feature = "rust1", since = "1.0.0")] |
1199 | impl<T> ops::Index<ops::RangeFrom<usize>> for Vec<T> { | |
1a4d82fc | 1200 | type Output = [T]; |
c34b1796 | 1201 | |
1a4d82fc | 1202 | #[inline] |
c34b1796 | 1203 | fn index(&self, index: ops::RangeFrom<usize>) -> &[T] { |
85aaf69f | 1204 | Index::index(&**self, index) |
1a4d82fc JJ |
1205 | } |
1206 | } | |
85aaf69f SL |
1207 | #[stable(feature = "rust1", since = "1.0.0")] |
1208 | impl<T> ops::Index<ops::RangeFull> for Vec<T> { | |
1a4d82fc | 1209 | type Output = [T]; |
c34b1796 | 1210 | |
1a4d82fc | 1211 | #[inline] |
c34b1796 AL |
1212 | fn index(&self, _index: ops::RangeFull) -> &[T] { |
1213 | self | |
1a4d82fc JJ |
1214 | } |
1215 | } | |
54a0048b SL |
1216 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
1217 | impl<T> ops::Index<ops::RangeInclusive<usize>> for Vec<T> { | |
1218 | type Output = [T]; | |
1219 | ||
1220 | #[inline] | |
1221 | fn index(&self, index: ops::RangeInclusive<usize>) -> &[T] { | |
1222 | Index::index(&**self, index) | |
1223 | } | |
1224 | } | |
1225 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] | |
1226 | impl<T> ops::Index<ops::RangeToInclusive<usize>> for Vec<T> { | |
1227 | type Output = [T]; | |
1228 | ||
1229 | #[inline] | |
1230 | fn index(&self, index: ops::RangeToInclusive<usize>) -> &[T] { | |
1231 | Index::index(&**self, index) | |
1232 | } | |
1233 | } | |
1a4d82fc | 1234 | |
85aaf69f SL |
1235 | #[stable(feature = "rust1", since = "1.0.0")] |
1236 | impl<T> ops::IndexMut<ops::Range<usize>> for Vec<T> { | |
1a4d82fc | 1237 | #[inline] |
c34b1796 | 1238 | fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [T] { |
85aaf69f | 1239 | IndexMut::index_mut(&mut **self, index) |
1a4d82fc JJ |
1240 | } |
1241 | } | |
85aaf69f SL |
1242 | #[stable(feature = "rust1", since = "1.0.0")] |
1243 | impl<T> ops::IndexMut<ops::RangeTo<usize>> for Vec<T> { | |
1a4d82fc | 1244 | #[inline] |
c34b1796 | 1245 | fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut [T] { |
85aaf69f | 1246 | IndexMut::index_mut(&mut **self, index) |
1a4d82fc JJ |
1247 | } |
1248 | } | |
85aaf69f SL |
1249 | #[stable(feature = "rust1", since = "1.0.0")] |
1250 | impl<T> ops::IndexMut<ops::RangeFrom<usize>> for Vec<T> { | |
1a4d82fc | 1251 | #[inline] |
c34b1796 | 1252 | fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut [T] { |
85aaf69f | 1253 | IndexMut::index_mut(&mut **self, index) |
1a4d82fc JJ |
1254 | } |
1255 | } | |
85aaf69f SL |
1256 | #[stable(feature = "rust1", since = "1.0.0")] |
1257 | impl<T> ops::IndexMut<ops::RangeFull> for Vec<T> { | |
1a4d82fc | 1258 | #[inline] |
c34b1796 AL |
1259 | fn index_mut(&mut self, _index: ops::RangeFull) -> &mut [T] { |
1260 | self | |
1a4d82fc JJ |
1261 | } |
1262 | } | |
54a0048b SL |
1263 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
1264 | impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for Vec<T> { | |
1265 | #[inline] | |
1266 | fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut [T] { | |
1267 | IndexMut::index_mut(&mut **self, index) | |
1268 | } | |
1269 | } | |
1270 | #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] | |
1271 | impl<T> ops::IndexMut<ops::RangeToInclusive<usize>> for Vec<T> { | |
1272 | #[inline] | |
1273 | fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut [T] { | |
1274 | IndexMut::index_mut(&mut **self, index) | |
1275 | } | |
1276 | } | |
1a4d82fc | 1277 | |
85aaf69f | 1278 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1279 | impl<T> ops::Deref for Vec<T> { |
1280 | type Target = [T]; | |
1281 | ||
c34b1796 AL |
1282 | fn deref(&self) -> &[T] { |
1283 | unsafe { | |
c1a9b12d | 1284 | let p = self.buf.ptr(); |
e9174d1e | 1285 | assume(!p.is_null()); |
c34b1796 AL |
1286 | slice::from_raw_parts(p, self.len) |
1287 | } | |
1288 | } | |
1a4d82fc JJ |
1289 | } |
1290 | ||
85aaf69f | 1291 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1292 | impl<T> ops::DerefMut for Vec<T> { |
c34b1796 AL |
1293 | fn deref_mut(&mut self) -> &mut [T] { |
1294 | unsafe { | |
c1a9b12d | 1295 | let ptr = self.buf.ptr(); |
c34b1796 AL |
1296 | assume(!ptr.is_null()); |
1297 | slice::from_raw_parts_mut(ptr, self.len) | |
1298 | } | |
1299 | } | |
1a4d82fc JJ |
1300 | } |
1301 | ||
85aaf69f | 1302 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1303 | impl<T> FromIterator<T> for Vec<T> { |
1304 | #[inline] | |
54a0048b | 1305 | fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Vec<T> { |
62682a34 SL |
1306 | // Unroll the first iteration, as the vector is going to be |
1307 | // expanded on this iteration in every case when the iterable is not | |
1308 | // empty, but the loop in extend_desugared() is not going to see the | |
1309 | // vector being full in the few subsequent loop iterations. | |
92a42be0 | 1310 | // So we get better branch prediction. |
54a0048b | 1311 | let mut iterator = iter.into_iter(); |
62682a34 SL |
1312 | let mut vector = match iterator.next() { |
1313 | None => return Vec::new(), | |
1314 | Some(element) => { | |
1315 | let (lower, _) = iterator.size_hint(); | |
1316 | let mut vector = Vec::with_capacity(lower.saturating_add(1)); | |
1317 | unsafe { | |
1318 | ptr::write(vector.get_unchecked_mut(0), element); | |
1319 | vector.set_len(1); | |
1320 | } | |
1321 | vector | |
85aaf69f | 1322 | } |
62682a34 SL |
1323 | }; |
1324 | vector.extend_desugared(iterator); | |
1a4d82fc JJ |
1325 | vector |
1326 | } | |
1327 | } | |
1328 | ||
85aaf69f SL |
1329 | #[stable(feature = "rust1", since = "1.0.0")] |
1330 | impl<T> IntoIterator for Vec<T> { | |
1331 | type Item = T; | |
1332 | type IntoIter = IntoIter<T>; | |
1333 | ||
9346a6ac AL |
1334 | /// Creates a consuming iterator, that is, one that moves each value out of |
1335 | /// the vector (from start to end). The vector cannot be used after calling | |
1336 | /// this. | |
1337 | /// | |
1338 | /// # Examples | |
1339 | /// | |
1340 | /// ``` | |
1341 | /// let v = vec!["a".to_string(), "b".to_string()]; | |
1342 | /// for s in v.into_iter() { | |
1343 | /// // s has type String, not &String | |
1344 | /// println!("{}", s); | |
1345 | /// } | |
1346 | /// ``` | |
1347 | #[inline] | |
c1a9b12d | 1348 | fn into_iter(mut self) -> IntoIter<T> { |
9346a6ac | 1349 | unsafe { |
c1a9b12d | 1350 | let ptr = self.as_mut_ptr(); |
9346a6ac | 1351 | assume(!ptr.is_null()); |
9346a6ac AL |
1352 | let begin = ptr as *const T; |
1353 | let end = if mem::size_of::<T>() == 0 { | |
62682a34 | 1354 | arith_offset(ptr as *const i8, self.len() as isize) as *const T |
9346a6ac AL |
1355 | } else { |
1356 | ptr.offset(self.len() as isize) as *const T | |
1357 | }; | |
c1a9b12d | 1358 | let buf = ptr::read(&self.buf); |
9346a6ac | 1359 | mem::forget(self); |
92a42be0 SL |
1360 | IntoIter { |
1361 | _buf: buf, | |
1362 | ptr: begin, | |
1363 | end: end, | |
1364 | } | |
9346a6ac | 1365 | } |
85aaf69f SL |
1366 | } |
1367 | } | |
1368 | ||
1369 | #[stable(feature = "rust1", since = "1.0.0")] | |
1370 | impl<'a, T> IntoIterator for &'a Vec<T> { | |
1371 | type Item = &'a T; | |
1372 | type IntoIter = slice::Iter<'a, T>; | |
1373 | ||
1374 | fn into_iter(self) -> slice::Iter<'a, T> { | |
1375 | self.iter() | |
1376 | } | |
1377 | } | |
1378 | ||
1379 | #[stable(feature = "rust1", since = "1.0.0")] | |
1380 | impl<'a, T> IntoIterator for &'a mut Vec<T> { | |
1381 | type Item = &'a mut T; | |
1382 | type IntoIter = slice::IterMut<'a, T>; | |
1383 | ||
1384 | fn into_iter(mut self) -> slice::IterMut<'a, T> { | |
1385 | self.iter_mut() | |
1386 | } | |
1387 | } | |
1388 | ||
bd371182 | 1389 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1390 | impl<T> Extend<T> for Vec<T> { |
1391 | #[inline] | |
54a0048b SL |
1392 | fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { |
1393 | self.extend_desugared(iter.into_iter()) | |
62682a34 SL |
1394 | } |
1395 | } | |
1396 | ||
1397 | impl<T> Vec<T> { | |
92a42be0 | 1398 | fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) { |
62682a34 SL |
1399 | // This function should be the moral equivalent of: |
1400 | // | |
1401 | // for item in iterator { | |
1402 | // self.push(item); | |
1403 | // } | |
1404 | while let Some(element) = iterator.next() { | |
1405 | let len = self.len(); | |
1406 | if len == self.capacity() { | |
1407 | let (lower, _) = iterator.size_hint(); | |
1408 | self.reserve(lower.saturating_add(1)); | |
1409 | } | |
1410 | unsafe { | |
1411 | ptr::write(self.get_unchecked_mut(len), element); | |
1412 | // NB can't overflow since we would have had to alloc the address space | |
1413 | self.set_len(len + 1); | |
1414 | } | |
1a4d82fc JJ |
1415 | } |
1416 | } | |
1417 | } | |
1418 | ||
62682a34 SL |
1419 | #[stable(feature = "extend_ref", since = "1.2.0")] |
1420 | impl<'a, T: 'a + Copy> Extend<&'a T> for Vec<T> { | |
92a42be0 | 1421 | fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
62682a34 SL |
1422 | self.extend(iter.into_iter().cloned()); |
1423 | } | |
1424 | } | |
1425 | ||
92a42be0 SL |
1426 | macro_rules! __impl_slice_eq1 { |
1427 | ($Lhs: ty, $Rhs: ty) => { | |
1428 | __impl_slice_eq1! { $Lhs, $Rhs, Sized } | |
1429 | }; | |
1430 | ($Lhs: ty, $Rhs: ty, $Bound: ident) => { | |
1431 | #[stable(feature = "rust1", since = "1.0.0")] | |
1432 | impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> { | |
1433 | #[inline] | |
1434 | fn eq(&self, other: &$Rhs) -> bool { self[..] == other[..] } | |
1435 | #[inline] | |
1436 | fn ne(&self, other: &$Rhs) -> bool { self[..] != other[..] } | |
1437 | } | |
1438 | } | |
1439 | } | |
1440 | ||
c34b1796 AL |
1441 | __impl_slice_eq1! { Vec<A>, Vec<B> } |
1442 | __impl_slice_eq1! { Vec<A>, &'b [B] } | |
1443 | __impl_slice_eq1! { Vec<A>, &'b mut [B] } | |
1444 | __impl_slice_eq1! { Cow<'a, [A]>, &'b [B], Clone } | |
1445 | __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B], Clone } | |
1446 | __impl_slice_eq1! { Cow<'a, [A]>, Vec<B>, Clone } | |
1447 | ||
1448 | macro_rules! array_impls { | |
1449 | ($($N: expr)+) => { | |
1450 | $( | |
1451 | // NOTE: some less important impls are omitted to reduce code bloat | |
1452 | __impl_slice_eq1! { Vec<A>, [B; $N] } | |
1453 | __impl_slice_eq1! { Vec<A>, &'b [B; $N] } | |
1454 | // __impl_slice_eq1! { Vec<A>, &'b mut [B; $N] } | |
1455 | // __impl_slice_eq1! { Cow<'a, [A]>, [B; $N], Clone } | |
1456 | // __impl_slice_eq1! { Cow<'a, [A]>, &'b [B; $N], Clone } | |
1457 | // __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B; $N], Clone } | |
1458 | )+ | |
1a4d82fc JJ |
1459 | } |
1460 | } | |
1461 | ||
c34b1796 AL |
1462 | array_impls! { |
1463 | 0 1 2 3 4 5 6 7 8 9 | |
1464 | 10 11 12 13 14 15 16 17 18 19 | |
1465 | 20 21 22 23 24 25 26 27 28 29 | |
1466 | 30 31 32 | |
1a4d82fc JJ |
1467 | } |
1468 | ||
85aaf69f | 1469 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1470 | impl<T: PartialOrd> PartialOrd for Vec<T> { |
1471 | #[inline] | |
1472 | fn partial_cmp(&self, other: &Vec<T>) -> Option<Ordering> { | |
85aaf69f | 1473 | PartialOrd::partial_cmp(&**self, &**other) |
1a4d82fc JJ |
1474 | } |
1475 | } | |
1476 | ||
85aaf69f | 1477 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1478 | impl<T: Eq> Eq for Vec<T> {} |
1479 | ||
85aaf69f | 1480 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1481 | impl<T: Ord> Ord for Vec<T> { |
1482 | #[inline] | |
1483 | fn cmp(&self, other: &Vec<T>) -> Ordering { | |
85aaf69f | 1484 | Ord::cmp(&**self, &**other) |
1a4d82fc JJ |
1485 | } |
1486 | } | |
1487 | ||
85aaf69f | 1488 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1489 | impl<T> Drop for Vec<T> { |
b039eaaf | 1490 | #[unsafe_destructor_blind_to_params] |
1a4d82fc | 1491 | fn drop(&mut self) { |
c1a9b12d | 1492 | if self.buf.unsafe_no_drop_flag_needs_drop() { |
b039eaaf | 1493 | unsafe { |
54a0048b SL |
1494 | // use drop for [T] |
1495 | ptr::drop_in_place(&mut self[..]); | |
1a4d82fc JJ |
1496 | } |
1497 | } | |
c1a9b12d | 1498 | // RawVec handles deallocation |
1a4d82fc JJ |
1499 | } |
1500 | } | |
1501 | ||
85aaf69f | 1502 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1503 | impl<T> Default for Vec<T> { |
1a4d82fc JJ |
1504 | fn default() -> Vec<T> { |
1505 | Vec::new() | |
1506 | } | |
1507 | } | |
1508 | ||
85aaf69f SL |
1509 | #[stable(feature = "rust1", since = "1.0.0")] |
1510 | impl<T: fmt::Debug> fmt::Debug for Vec<T> { | |
1a4d82fc | 1511 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
85aaf69f | 1512 | fmt::Debug::fmt(&**self, f) |
1a4d82fc JJ |
1513 | } |
1514 | } | |
1515 | ||
c34b1796 AL |
1516 | #[stable(feature = "rust1", since = "1.0.0")] |
1517 | impl<T> AsRef<Vec<T>> for Vec<T> { | |
1518 | fn as_ref(&self) -> &Vec<T> { | |
1519 | self | |
1520 | } | |
1521 | } | |
1522 | ||
b039eaaf SL |
1523 | #[stable(feature = "vec_as_mut", since = "1.5.0")] |
1524 | impl<T> AsMut<Vec<T>> for Vec<T> { | |
1525 | fn as_mut(&mut self) -> &mut Vec<T> { | |
1526 | self | |
1527 | } | |
1528 | } | |
1529 | ||
c34b1796 AL |
1530 | #[stable(feature = "rust1", since = "1.0.0")] |
1531 | impl<T> AsRef<[T]> for Vec<T> { | |
1532 | fn as_ref(&self) -> &[T] { | |
1533 | self | |
1534 | } | |
1535 | } | |
1536 | ||
b039eaaf SL |
1537 | #[stable(feature = "vec_as_mut", since = "1.5.0")] |
1538 | impl<T> AsMut<[T]> for Vec<T> { | |
1539 | fn as_mut(&mut self) -> &mut [T] { | |
1540 | self | |
1541 | } | |
1542 | } | |
1543 | ||
c34b1796 AL |
1544 | #[stable(feature = "rust1", since = "1.0.0")] |
1545 | impl<'a, T: Clone> From<&'a [T]> for Vec<T> { | |
1546 | #[cfg(not(test))] | |
1547 | fn from(s: &'a [T]) -> Vec<T> { | |
1548 | s.to_vec() | |
1549 | } | |
1550 | #[cfg(test)] | |
1551 | fn from(s: &'a [T]) -> Vec<T> { | |
1552 | ::slice::to_vec(s) | |
1553 | } | |
1554 | } | |
1555 | ||
1556 | #[stable(feature = "rust1", since = "1.0.0")] | |
1557 | impl<'a> From<&'a str> for Vec<u8> { | |
1558 | fn from(s: &'a str) -> Vec<u8> { | |
1559 | From::from(s.as_bytes()) | |
1560 | } | |
1561 | } | |
1562 | ||
1a4d82fc JJ |
1563 | //////////////////////////////////////////////////////////////////////////////// |
1564 | // Clone-on-write | |
1565 | //////////////////////////////////////////////////////////////////////////////// | |
1566 | ||
7453a54e SL |
1567 | #[stable(feature = "cow_from_vec", since = "1.7.0")] |
1568 | impl<'a, T: Clone> From<&'a [T]> for Cow<'a, [T]> { | |
1569 | fn from(s: &'a [T]) -> Cow<'a, [T]> { | |
1570 | Cow::Borrowed(s) | |
1571 | } | |
1572 | } | |
1573 | ||
1574 | #[stable(feature = "cow_from_vec", since = "1.7.0")] | |
1575 | impl<'a, T: Clone> From<Vec<T>> for Cow<'a, [T]> { | |
1576 | fn from(v: Vec<T>) -> Cow<'a, [T]> { | |
1577 | Cow::Owned(v) | |
1578 | } | |
1579 | } | |
1580 | ||
bd371182 | 1581 | #[stable(feature = "rust1", since = "1.0.0")] |
85aaf69f | 1582 | impl<'a, T> FromIterator<T> for Cow<'a, [T]> where T: Clone { |
92a42be0 | 1583 | fn from_iter<I: IntoIterator<Item = T>>(it: I) -> Cow<'a, [T]> { |
1a4d82fc JJ |
1584 | Cow::Owned(FromIterator::from_iter(it)) |
1585 | } | |
1586 | } | |
1587 | ||
1a4d82fc JJ |
1588 | //////////////////////////////////////////////////////////////////////////////// |
1589 | // Iterators | |
1590 | //////////////////////////////////////////////////////////////////////////////// | |
1591 | ||
1592 | /// An iterator that moves out of a vector. | |
85aaf69f | 1593 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1594 | pub struct IntoIter<T> { |
e9174d1e | 1595 | _buf: RawVec<T>, |
1a4d82fc | 1596 | ptr: *const T, |
92a42be0 | 1597 | end: *const T, |
1a4d82fc JJ |
1598 | } |
1599 | ||
92a42be0 SL |
1600 | #[stable(feature = "rust1", since = "1.0.0")] |
1601 | unsafe impl<T: Send> Send for IntoIter<T> {} | |
1602 | #[stable(feature = "rust1", since = "1.0.0")] | |
1603 | unsafe impl<T: Sync> Sync for IntoIter<T> {} | |
85aaf69f | 1604 | |
85aaf69f | 1605 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1606 | impl<T> Iterator for IntoIter<T> { |
1607 | type Item = T; | |
1608 | ||
1609 | #[inline] | |
85aaf69f | 1610 | fn next(&mut self) -> Option<T> { |
1a4d82fc JJ |
1611 | unsafe { |
1612 | if self.ptr == self.end { | |
1613 | None | |
1614 | } else { | |
1615 | if mem::size_of::<T>() == 0 { | |
1616 | // purposefully don't use 'ptr.offset' because for | |
1617 | // vectors with 0-size elements this would return the | |
1618 | // same pointer. | |
62682a34 | 1619 | self.ptr = arith_offset(self.ptr as *const i8, 1) as *const T; |
1a4d82fc JJ |
1620 | |
1621 | // Use a non-null pointer value | |
85aaf69f | 1622 | Some(ptr::read(EMPTY as *mut T)) |
1a4d82fc JJ |
1623 | } else { |
1624 | let old = self.ptr; | |
1625 | self.ptr = self.ptr.offset(1); | |
1626 | ||
1627 | Some(ptr::read(old)) | |
1628 | } | |
1629 | } | |
1630 | } | |
1631 | } | |
1632 | ||
1633 | #[inline] | |
85aaf69f SL |
1634 | fn size_hint(&self) -> (usize, Option<usize>) { |
1635 | let diff = (self.end as usize) - (self.ptr as usize); | |
1a4d82fc | 1636 | let size = mem::size_of::<T>(); |
92a42be0 SL |
1637 | let exact = diff / |
1638 | (if size == 0 { | |
1639 | 1 | |
1640 | } else { | |
1641 | size | |
1642 | }); | |
1a4d82fc JJ |
1643 | (exact, Some(exact)) |
1644 | } | |
d9579d0f AL |
1645 | |
1646 | #[inline] | |
1647 | fn count(self) -> usize { | |
1648 | self.size_hint().0 | |
1649 | } | |
1a4d82fc JJ |
1650 | } |
1651 | ||
85aaf69f | 1652 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1653 | impl<T> DoubleEndedIterator for IntoIter<T> { |
1654 | #[inline] | |
85aaf69f | 1655 | fn next_back(&mut self) -> Option<T> { |
1a4d82fc JJ |
1656 | unsafe { |
1657 | if self.end == self.ptr { | |
1658 | None | |
1659 | } else { | |
1660 | if mem::size_of::<T>() == 0 { | |
1661 | // See above for why 'ptr.offset' isn't used | |
62682a34 | 1662 | self.end = arith_offset(self.end as *const i8, -1) as *const T; |
1a4d82fc JJ |
1663 | |
1664 | // Use a non-null pointer value | |
85aaf69f | 1665 | Some(ptr::read(EMPTY as *mut T)) |
1a4d82fc JJ |
1666 | } else { |
1667 | self.end = self.end.offset(-1); | |
1668 | ||
e9174d1e | 1669 | Some(ptr::read(self.end)) |
1a4d82fc JJ |
1670 | } |
1671 | } | |
1672 | } | |
1673 | } | |
1674 | } | |
1675 | ||
85aaf69f | 1676 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1677 | impl<T> ExactSizeIterator for IntoIter<T> {} |
1678 | ||
7453a54e SL |
1679 | #[stable(feature = "vec_into_iter_clone", since = "1.8.0")] |
1680 | impl<T: Clone> Clone for IntoIter<T> { | |
1681 | fn clone(&self) -> IntoIter<T> { | |
1682 | unsafe { | |
1683 | slice::from_raw_parts(self.ptr, self.len()).to_owned().into_iter() | |
1684 | } | |
1685 | } | |
1686 | } | |
1687 | ||
85aaf69f | 1688 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1689 | impl<T> Drop for IntoIter<T> { |
b039eaaf | 1690 | #[unsafe_destructor_blind_to_params] |
1a4d82fc JJ |
1691 | fn drop(&mut self) { |
1692 | // destroy the remaining elements | |
b039eaaf | 1693 | for _x in self {} |
c1a9b12d SL |
1694 | |
1695 | // RawVec handles deallocation | |
1a4d82fc JJ |
1696 | } |
1697 | } | |
1698 | ||
d9579d0f | 1699 | /// A draining iterator for `Vec<T>`. |
92a42be0 | 1700 | #[stable(feature = "drain", since = "1.6.0")] |
d9579d0f AL |
1701 | pub struct Drain<'a, T: 'a> { |
1702 | /// Index of tail to preserve | |
1703 | tail_start: usize, | |
1704 | /// Length of tail | |
1705 | tail_len: usize, | |
1706 | /// Current remaining range to remove | |
1707 | iter: slice::IterMut<'a, T>, | |
1708 | vec: *mut Vec<T>, | |
1a4d82fc JJ |
1709 | } |
1710 | ||
92a42be0 | 1711 | #[stable(feature = "drain", since = "1.6.0")] |
c34b1796 | 1712 | unsafe impl<'a, T: Sync> Sync for Drain<'a, T> {} |
92a42be0 | 1713 | #[stable(feature = "drain", since = "1.6.0")] |
c34b1796 AL |
1714 | unsafe impl<'a, T: Send> Send for Drain<'a, T> {} |
1715 | ||
85aaf69f | 1716 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1717 | impl<'a, T> Iterator for Drain<'a, T> { |
1718 | type Item = T; | |
1719 | ||
1720 | #[inline] | |
1721 | fn next(&mut self) -> Option<T> { | |
92a42be0 | 1722 | self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) }) |
1a4d82fc JJ |
1723 | } |
1724 | ||
85aaf69f | 1725 | fn size_hint(&self) -> (usize, Option<usize>) { |
d9579d0f | 1726 | self.iter.size_hint() |
1a4d82fc JJ |
1727 | } |
1728 | } | |
1729 | ||
85aaf69f | 1730 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1731 | impl<'a, T> DoubleEndedIterator for Drain<'a, T> { |
1732 | #[inline] | |
1733 | fn next_back(&mut self) -> Option<T> { | |
92a42be0 | 1734 | self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) }) |
1a4d82fc JJ |
1735 | } |
1736 | } | |
1737 | ||
85aaf69f | 1738 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1739 | impl<'a, T> Drop for Drain<'a, T> { |
1740 | fn drop(&mut self) { | |
d9579d0f | 1741 | // exhaust self first |
92a42be0 | 1742 | while let Some(_) = self.next() {} |
1a4d82fc | 1743 | |
d9579d0f AL |
1744 | if self.tail_len > 0 { |
1745 | unsafe { | |
1746 | let source_vec = &mut *self.vec; | |
1747 | // memmove back untouched tail, update to new length | |
1748 | let start = source_vec.len(); | |
1749 | let tail = self.tail_start; | |
1750 | let src = source_vec.as_ptr().offset(tail as isize); | |
1751 | let dst = source_vec.as_mut_ptr().offset(start as isize); | |
1752 | ptr::copy(src, dst, self.tail_len); | |
1753 | source_vec.set_len(start + self.tail_len); | |
1754 | } | |
1755 | } | |
1a4d82fc JJ |
1756 | } |
1757 | } | |
1758 | ||
d9579d0f AL |
1759 | |
1760 | #[stable(feature = "rust1", since = "1.0.0")] | |
1761 | impl<'a, T> ExactSizeIterator for Drain<'a, T> {} |