| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! A contiguous growable array type with heap-allocated contents, written |
| //! `Vec<T>` but pronounced 'vector.' |
| //! |
| //! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and |
| //! `O(1)` pop (from the end). |
| //! |
| //! # Examples |
| //! |
| //! You can explicitly create a `Vec<T>` with `new()`: |
| //! |
| //! ``` |
| //! let v: Vec<i32> = Vec::new(); |
| //! ``` |
| //! |
| //! ...or by using the `vec!` macro: |
| //! |
| //! ``` |
| //! let v: Vec<i32> = vec![]; |
| //! |
| //! let v = vec![1, 2, 3, 4, 5]; |
| //! |
| //! let v = vec![0; 10]; // ten zeroes |
| //! ``` |
| //! |
| //! You can `push` values onto the end of a vector (which will grow the vector |
| //! as needed): |
| //! |
| //! ``` |
| //! let mut v = vec![1, 2]; |
| //! |
| //! v.push(3); |
| //! ``` |
| //! |
| //! Popping values works in much the same way: |
| //! |
| //! ``` |
| //! let mut v = vec![1, 2]; |
| //! |
| //! let two = v.pop(); |
| //! ``` |
| //! |
| //! Vectors also support indexing (through the `Index` and `IndexMut` traits): |
| //! |
| //! ``` |
| //! let mut v = vec![1, 2, 3]; |
| //! let three = v[2]; |
| //! v[1] = v[1] + 5; |
| //! ``` |
| |
| #![stable(feature = "rust1", since = "1.0.0")] |
| |
| use alloc::boxed::Box; |
| use alloc::heap::EMPTY; |
| use alloc::raw_vec::RawVec; |
| use borrow::ToOwned; |
| use borrow::Cow; |
| use core::cmp::Ordering; |
| use core::fmt; |
| use core::hash::{self, Hash}; |
| use core::intrinsics::{arith_offset, assume}; |
| use core::iter::FromIterator; |
| use core::mem; |
| use core::ops::{Index, IndexMut}; |
| use core::ops; |
| use core::ptr; |
| use core::ptr::Shared; |
| use core::slice; |
| |
| use super::SpecExtend; |
| use super::range::RangeArgument; |
| |
| /// A contiguous growable array type, written `Vec<T>` but pronounced 'vector.' |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = Vec::new(); |
| /// vec.push(1); |
| /// vec.push(2); |
| /// |
| /// assert_eq!(vec.len(), 2); |
| /// assert_eq!(vec[0], 1); |
| /// |
| /// assert_eq!(vec.pop(), Some(2)); |
| /// assert_eq!(vec.len(), 1); |
| /// |
| /// vec[0] = 7; |
| /// assert_eq!(vec[0], 7); |
| /// |
| /// vec.extend([1, 2, 3].iter().cloned()); |
| /// |
| /// for x in &vec { |
| /// println!("{}", x); |
| /// } |
| /// assert_eq!(vec, [7, 1, 2, 3]); |
| /// ``` |
| /// |
| /// The `vec!` macro is provided to make initialization more convenient: |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// vec.push(4); |
| /// assert_eq!(vec, [1, 2, 3, 4]); |
| /// ``` |
| /// |
| /// It can also initialize each element of a `Vec<T>` with a given value: |
| /// |
| /// ``` |
| /// let vec = vec![0; 5]; |
| /// assert_eq!(vec, [0, 0, 0, 0, 0]); |
| /// ``` |
| /// |
| /// Use a `Vec<T>` as an efficient stack: |
| /// |
| /// ``` |
| /// let mut stack = Vec::new(); |
| /// |
| /// stack.push(1); |
| /// stack.push(2); |
| /// stack.push(3); |
| /// |
| /// while let Some(top) = stack.pop() { |
| /// // Prints 3, 2, 1 |
| /// println!("{}", top); |
| /// } |
| /// ``` |
| /// |
| /// # Indexing |
| /// |
| /// The Vec type allows to access values by index, because it implements the |
| /// `Index` trait. An example will be more explicit: |
| /// |
| /// ``` |
| /// let v = vec!(0, 2, 4, 6); |
| /// println!("{}", v[1]); // it will display '2' |
| /// ``` |
| /// |
| /// However be careful: if you try to access an index which isn't in the Vec, |
| /// your software will panic! You cannot do this: |
| /// |
| /// ```ignore |
| /// let v = vec!(0, 2, 4, 6); |
| /// println!("{}", v[6]); // it will panic! |
| /// ``` |
| /// |
| /// In conclusion: always check if the index you want to get really exists |
| /// before doing it. |
| /// |
| /// # Slicing |
| /// |
| /// A Vec can be mutable. Slices, on the other hand, are read-only objects. |
| /// To get a slice, use "&". Example: |
| /// |
| /// ``` |
| /// fn read_slice(slice: &[usize]) { |
| /// // ... |
| /// } |
| /// |
| /// let v = vec!(0, 1); |
| /// read_slice(&v); |
| /// |
| /// // ... and that's all! |
| /// // you can also do it like this: |
| /// let x : &[usize] = &v; |
| /// ``` |
| /// |
| /// In Rust, it's more common to pass slices as arguments rather than vectors |
| /// when you just want to provide a read access. The same goes for String and |
| /// &str. |
| /// |
| /// # Capacity and reallocation |
| /// |
| /// The capacity of a vector is the amount of space allocated for any future |
| /// elements that will be added onto the vector. This is not to be confused with |
| /// the *length* of a vector, which specifies the number of actual elements |
| /// within the vector. If a vector's length exceeds its capacity, its capacity |
| /// will automatically be increased, but its elements will have to be |
| /// reallocated. |
| /// |
| /// For example, a vector with capacity 10 and length 0 would be an empty vector |
| /// with space for 10 more elements. Pushing 10 or fewer elements onto the |
| /// vector will not change its capacity or cause reallocation to occur. However, |
| /// if the vector's length is increased to 11, it will have to reallocate, which |
| /// can be slow. For this reason, it is recommended to use `Vec::with_capacity` |
| /// whenever possible to specify how big the vector is expected to get. |
| /// |
| /// # Guarantees |
| /// |
| /// Due to its incredibly fundamental nature, Vec makes a lot of guarantees |
| /// about its design. This ensures that it's as low-overhead as possible in |
| /// the general case, and can be correctly manipulated in primitive ways |
| /// by unsafe code. Note that these guarantees refer to an unqualified `Vec<T>`. |
| /// If additional type parameters are added (e.g. to support custom allocators), |
| /// overriding their defaults may change the behavior. |
| /// |
| /// Most fundamentally, Vec is and always will be a (pointer, capacity, length) |
| /// triplet. No more, no less. The order of these fields is completely |
| /// unspecified, and you should use the appropriate methods to modify these. |
| /// The pointer will never be null, so this type is null-pointer-optimized. |
| /// |
| /// However, the pointer may not actually point to allocated memory. In particular, |
| /// if you construct a Vec with capacity 0 via `Vec::new()`, `vec![]`, |
| /// `Vec::with_capacity(0)`, or by calling `shrink_to_fit()` on an empty Vec, it |
| /// will not allocate memory. Similarly, if you store zero-sized types inside |
| /// a Vec, it will not allocate space for them. *Note that in this case the |
| /// Vec may not report a `capacity()` of 0*. Vec will allocate if and only |
| /// if `mem::size_of::<T>() * capacity() > 0`. In general, Vec's allocation |
| /// details are subtle enough that it is strongly recommended that you only |
| /// free memory allocated by a Vec by creating a new Vec and dropping it. |
| /// |
| /// If a Vec *has* allocated memory, then the memory it points to is on the heap |
| /// (as defined by the allocator Rust is configured to use by default), and its |
| /// pointer points to `len()` initialized elements in order (what you would see |
| /// if you coerced it to a slice), followed by `capacity() - len()` logically |
| /// uninitialized elements. |
| /// |
| /// Vec will never perform a "small optimization" where elements are actually |
| /// stored on the stack for two reasons: |
| /// |
| /// * It would make it more difficult for unsafe code to correctly manipulate |
| /// a Vec. The contents of a Vec wouldn't have a stable address if it were |
| /// only moved, and it would be more difficult to determine if a Vec had |
| /// actually allocated memory. |
| /// |
| /// * It would penalize the general case, incurring an additional branch |
| /// on every access. |
| /// |
| /// Vec will never automatically shrink itself, even if completely empty. This |
| /// ensures no unnecessary allocations or deallocations occur. Emptying a Vec |
| /// and then filling it back up to the same `len()` should incur no calls to |
| /// the allocator. If you wish to free up unused memory, use `shrink_to_fit`. |
| /// |
| /// `push` and `insert` will never (re)allocate if the reported capacity is |
| /// sufficient. `push` and `insert` *will* (re)allocate if `len() == capacity()`. |
| /// That is, the reported capacity is completely accurate, and can be relied on. |
| /// It can even be used to manually free the memory allocated by a Vec if |
| /// desired. Bulk insertion methods *may* reallocate, even when not necessary. |
| /// |
| /// Vec does not guarantee any particular growth strategy when reallocating |
| /// when full, nor when `reserve` is called. The current strategy is basic |
| /// and it may prove desirable to use a non-constant growth factor. Whatever |
| /// strategy is used will of course guarantee `O(1)` amortized `push`. |
| /// |
| /// `vec![x; n]`, `vec![a, b, c, d]`, and `Vec::with_capacity(n)`, will all |
| /// produce a Vec with exactly the requested capacity. If `len() == capacity()`, |
| /// (as is the case for the `vec!` macro), then a `Vec<T>` can be converted |
| /// to and from a `Box<[T]>` without reallocating or moving the elements. |
| /// |
| /// Vec will not specifically overwrite any data that is removed from it, |
| /// but also won't specifically preserve it. Its uninitialized memory is |
| /// scratch space that it may use however it wants. It will generally just do |
| /// whatever is most efficient or otherwise easy to implement. Do not rely on |
| /// removed data to be erased for security purposes. Even if you drop a Vec, its |
| /// buffer may simply be reused by another Vec. Even if you zero a Vec's memory |
| /// first, that may not actually happen because the optimizer does not consider |
| /// this a side-effect that must be preserved. |
| /// |
| /// Vec does not currently guarantee the order in which elements are dropped |
| /// (the order has changed in the past, and may change again). |
| /// |
| #[unsafe_no_drop_flag] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct Vec<T> { |
| buf: RawVec<T>, |
| len: usize, |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Inherent methods |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| impl<T> Vec<T> { |
| /// Constructs a new, empty `Vec<T>`. |
| /// |
| /// The vector will not allocate until elements are pushed onto it. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # #![allow(unused_mut)] |
| /// let mut vec: Vec<i32> = Vec::new(); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn new() -> Vec<T> { |
| Vec { |
| buf: RawVec::new(), |
| len: 0, |
| } |
| } |
| |
| /// Constructs a new, empty `Vec<T>` with the specified capacity. |
| /// |
| /// The vector will be able to hold exactly `capacity` elements without |
| /// reallocating. If `capacity` is 0, the vector will not allocate. |
| /// |
| /// It is important to note that this function does not specify the *length* |
| /// of the returned vector, but only the *capacity*. (For an explanation of |
| /// the difference between length and capacity, see the main `Vec<T>` docs |
| /// above, 'Capacity and reallocation'.) |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = Vec::with_capacity(10); |
| /// |
| /// // The vector contains no items, even though it has capacity for more |
| /// assert_eq!(vec.len(), 0); |
| /// |
| /// // These are all done without reallocating... |
| /// for i in 0..10 { |
| /// vec.push(i); |
| /// } |
| /// |
| /// // ...but this may make the vector reallocate |
| /// vec.push(11); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn with_capacity(capacity: usize) -> Vec<T> { |
| Vec { |
| buf: RawVec::with_capacity(capacity), |
| len: 0, |
| } |
| } |
| |
| /// Creates a `Vec<T>` directly from the raw components of another vector. |
| /// |
| /// # Safety |
| /// |
| /// This is highly unsafe, due to the number of invariants that aren't |
| /// checked: |
| /// |
| /// * `ptr` needs to have been previously allocated via `String`/`Vec<T>` |
| /// (at least, it's highly likely to be incorrect if it wasn't). |
| /// * `length` needs to be less than or equal to `capacity`. |
| /// * `capacity` needs to be the capacity that the pointer was allocated with. |
| /// |
| /// Violating these may cause problems like corrupting the allocator's |
| /// internal datastructures. |
| /// |
| /// The ownership of `ptr` is effectively transferred to the |
| /// `Vec<T>` which may then deallocate, reallocate or change the |
| /// contents of memory pointed to by the pointer at will. Ensure |
| /// that nothing else uses the pointer after calling this |
| /// function. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ptr; |
| /// use std::mem; |
| /// |
| /// fn main() { |
| /// let mut v = vec![1, 2, 3]; |
| /// |
| /// // Pull out the various important pieces of information about `v` |
| /// let p = v.as_mut_ptr(); |
| /// let len = v.len(); |
| /// let cap = v.capacity(); |
| /// |
| /// unsafe { |
| /// // Cast `v` into the void: no destructor run, so we are in |
| /// // complete control of the allocation to which `p` points. |
| /// mem::forget(v); |
| /// |
| /// // Overwrite memory with 4, 5, 6 |
| /// for i in 0..len as isize { |
| /// ptr::write(p.offset(i), 4 + i); |
| /// } |
| /// |
| /// // Put everything back together into a Vec |
| /// let rebuilt = Vec::from_raw_parts(p, len, cap); |
| /// assert_eq!(rebuilt, [4, 5, 6]); |
| /// } |
| /// } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Vec<T> { |
| Vec { |
| buf: RawVec::from_raw_parts(ptr, capacity), |
| len: length, |
| } |
| } |
| |
| /// Returns the number of elements the vector can hold without |
| /// reallocating. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let vec: Vec<i32> = Vec::with_capacity(10); |
| /// assert_eq!(vec.capacity(), 10); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn capacity(&self) -> usize { |
| self.buf.cap() |
| } |
| |
| /// Reserves capacity for at least `additional` more elements to be inserted |
| /// in the given `Vec<T>`. The collection may reserve more space to avoid |
| /// frequent reallocations. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the new capacity overflows `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1]; |
| /// vec.reserve(10); |
| /// assert!(vec.capacity() >= 11); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn reserve(&mut self, additional: usize) { |
| self.buf.reserve(self.len, additional); |
| } |
| |
| /// Reserves the minimum capacity for exactly `additional` more elements to |
| /// be inserted in the given `Vec<T>`. Does nothing if the capacity is already |
| /// sufficient. |
| /// |
| /// Note that the allocator may give the collection more space than it |
| /// requests. Therefore capacity can not be relied upon to be precisely |
| /// minimal. Prefer `reserve` if future insertions are expected. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the new capacity overflows `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1]; |
| /// vec.reserve_exact(10); |
| /// assert!(vec.capacity() >= 11); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn reserve_exact(&mut self, additional: usize) { |
| self.buf.reserve_exact(self.len, additional); |
| } |
| |
| /// Shrinks the capacity of the vector as much as possible. |
| /// |
| /// It will drop down as close as possible to the length but the allocator |
| /// may still inform the vector that there is space for a few more elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = Vec::with_capacity(10); |
| /// vec.extend([1, 2, 3].iter().cloned()); |
| /// assert_eq!(vec.capacity(), 10); |
| /// vec.shrink_to_fit(); |
| /// assert!(vec.capacity() >= 3); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn shrink_to_fit(&mut self) { |
| self.buf.shrink_to_fit(self.len); |
| } |
| |
| /// Converts the vector into Box<[T]>. |
| /// |
| /// Note that this will drop any excess capacity. Calling this and |
| /// converting back to a vector with `into_vec()` is equivalent to calling |
| /// `shrink_to_fit()`. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn into_boxed_slice(mut self) -> Box<[T]> { |
| unsafe { |
| self.shrink_to_fit(); |
| let buf = ptr::read(&self.buf); |
| mem::forget(self); |
| buf.into_box() |
| } |
| } |
| |
| /// Shortens the vector, keeping the first `len` elements and dropping |
| /// the rest. |
| /// |
| /// If `len` is greater than the vector's current length, this has no |
| /// effect. |
| /// |
| /// The [`drain`] method can emulate `truncate`, but causes the excess |
| /// elements to be returned instead of dropped. |
| /// |
| /// # Examples |
| /// |
| /// Truncating a five element vector to two elements: |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3, 4, 5]; |
| /// vec.truncate(2); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| /// |
| /// No truncation occurs when `len` is greater than the vector's current |
| /// length: |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// vec.truncate(8); |
| /// assert_eq!(vec, [1, 2, 3]); |
| /// ``` |
| /// |
| /// Truncating when `len == 0` is equivalent to calling the [`clear`] |
| /// method. |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// vec.truncate(0); |
| /// assert_eq!(vec, []); |
| /// ``` |
| /// |
| /// [`clear`]: #method.clear |
| /// [`drain`]: #method.drain |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn truncate(&mut self, len: usize) { |
| unsafe { |
| // drop any extra elements |
| while len < self.len { |
| // decrement len before the drop_in_place(), so a panic on Drop |
| // doesn't re-drop the just-failed value. |
| self.len -= 1; |
| let len = self.len; |
| ptr::drop_in_place(self.get_unchecked_mut(len)); |
| } |
| } |
| } |
| |
| /// Extracts a slice containing the entire vector. |
| /// |
| /// Equivalent to `&s[..]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::io::{self, Write}; |
| /// let buffer = vec![1, 2, 3, 5, 8]; |
| /// io::sink().write(buffer.as_slice()).unwrap(); |
| /// ``` |
| #[inline] |
| #[stable(feature = "vec_as_slice", since = "1.7.0")] |
| pub fn as_slice(&self) -> &[T] { |
| self |
| } |
| |
| /// Extracts a mutable slice of the entire vector. |
| /// |
| /// Equivalent to `&mut s[..]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::io::{self, Read}; |
| /// let mut buffer = vec![0; 3]; |
| /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap(); |
| /// ``` |
| #[inline] |
| #[stable(feature = "vec_as_slice", since = "1.7.0")] |
| pub fn as_mut_slice(&mut self) -> &mut [T] { |
| self |
| } |
| |
| /// Sets the length of a vector. |
| /// |
| /// This will explicitly set the size of the vector, without actually |
| /// modifying its buffers, so it is up to the caller to ensure that the |
| /// vector is actually the specified size. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::ptr; |
| /// |
| /// let mut vec = vec!['r', 'u', 's', 't']; |
| /// |
| /// unsafe { |
| /// ptr::drop_in_place(&mut vec[3]); |
| /// vec.set_len(3); |
| /// } |
| /// assert_eq!(vec, ['r', 'u', 's']); |
| /// ``` |
| /// |
| /// In this example, there is a memory leak since the memory locations |
| /// owned by the inner vectors were not freed prior to the `set_len` call: |
| /// |
| /// ``` |
| /// let mut vec = vec![vec![1, 0, 0], |
| /// vec![0, 1, 0], |
| /// vec![0, 0, 1]]; |
| /// unsafe { |
| /// vec.set_len(0); |
| /// } |
| /// ``` |
| /// |
| /// In this example, the vector gets expanded from zero to four items |
| /// without any memory allocations occurring, resulting in vector |
| /// values of unallocated memory: |
| /// |
| /// ``` |
| /// let mut vec: Vec<char> = Vec::new(); |
| /// |
| /// unsafe { |
| /// vec.set_len(4); |
| /// } |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub unsafe fn set_len(&mut self, len: usize) { |
| self.len = len; |
| } |
| |
| /// Removes an element from anywhere in the vector and return it, replacing |
| /// it with the last element. |
| /// |
| /// This does not preserve ordering, but is O(1). |
| /// |
| /// # Panics |
| /// |
| /// Panics if `index` is out of bounds. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = vec!["foo", "bar", "baz", "qux"]; |
| /// |
| /// assert_eq!(v.swap_remove(1), "bar"); |
| /// assert_eq!(v, ["foo", "qux", "baz"]); |
| /// |
| /// assert_eq!(v.swap_remove(0), "foo"); |
| /// assert_eq!(v, ["baz", "qux"]); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn swap_remove(&mut self, index: usize) -> T { |
| let length = self.len(); |
| self.swap(index, length - 1); |
| self.pop().unwrap() |
| } |
| |
| /// Inserts an element at position `index` within the vector, shifting all |
| /// elements after it to the right. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `index` is greater than the vector's length. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// vec.insert(1, 4); |
| /// assert_eq!(vec, [1, 4, 2, 3]); |
| /// vec.insert(4, 5); |
| /// assert_eq!(vec, [1, 4, 2, 3, 5]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn insert(&mut self, index: usize, element: T) { |
| let len = self.len(); |
| assert!(index <= len); |
| |
| // space for the new element |
| if len == self.buf.cap() { |
| self.buf.double(); |
| } |
| |
| unsafe { |
| // infallible |
| // The spot to put the new value |
| { |
| let p = self.as_mut_ptr().offset(index as isize); |
| // Shift everything over to make space. (Duplicating the |
| // `index`th element into two consecutive places.) |
| ptr::copy(p, p.offset(1), len - index); |
| // Write it in, overwriting the first copy of the `index`th |
| // element. |
| ptr::write(p, element); |
| } |
| self.set_len(len + 1); |
| } |
| } |
| |
| /// Removes and returns the element at position `index` within the vector, |
| /// shifting all elements after it to the left. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `index` is out of bounds. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = vec![1, 2, 3]; |
| /// assert_eq!(v.remove(1), 2); |
| /// assert_eq!(v, [1, 3]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn remove(&mut self, index: usize) -> T { |
| let len = self.len(); |
| assert!(index < len); |
| unsafe { |
| // infallible |
| let ret; |
| { |
| // the place we are taking from. |
| let ptr = self.as_mut_ptr().offset(index as isize); |
| // copy it out, unsafely having a copy of the value on |
| // the stack and in the vector at the same time. |
| ret = ptr::read(ptr); |
| |
| // Shift everything down to fill in that spot. |
| ptr::copy(ptr.offset(1), ptr, len - index - 1); |
| } |
| self.set_len(len - 1); |
| ret |
| } |
| } |
| |
| /// Retains only the elements specified by the predicate. |
| /// |
| /// In other words, remove all elements `e` such that `f(&e)` returns false. |
| /// This method operates in place and preserves the order of the retained |
| /// elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3, 4]; |
| /// vec.retain(|&x| x%2 == 0); |
| /// assert_eq!(vec, [2, 4]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn retain<F>(&mut self, mut f: F) |
| where F: FnMut(&T) -> bool |
| { |
| let len = self.len(); |
| let mut del = 0; |
| { |
| let v = &mut **self; |
| |
| for i in 0..len { |
| if !f(&v[i]) { |
| del += 1; |
| } else if del > 0 { |
| v.swap(i - del, i); |
| } |
| } |
| } |
| if del > 0 { |
| self.truncate(len - del); |
| } |
| } |
| |
| /// Appends an element to the back of a collection. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the number of elements in the vector overflows a `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2]; |
| /// vec.push(3); |
| /// assert_eq!(vec, [1, 2, 3]); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn push(&mut self, value: T) { |
| // This will panic or abort if we would allocate > isize::MAX bytes |
| // or if the length increment would overflow for zero-sized types. |
| if self.len == self.buf.cap() { |
| self.buf.double(); |
| } |
| unsafe { |
| let end = self.as_mut_ptr().offset(self.len as isize); |
| ptr::write(end, value); |
| self.len += 1; |
| } |
| } |
| |
| /// Removes the last element from a vector and returns it, or `None` if it |
| /// is empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// assert_eq!(vec.pop(), Some(3)); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn pop(&mut self) -> Option<T> { |
| if self.len == 0 { |
| None |
| } else { |
| unsafe { |
| self.len -= 1; |
| Some(ptr::read(self.get_unchecked(self.len()))) |
| } |
| } |
| } |
| |
| /// Moves all the elements of `other` into `Self`, leaving `other` empty. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the number of elements in the vector overflows a `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 3]; |
| /// let mut vec2 = vec![4, 5, 6]; |
| /// vec.append(&mut vec2); |
| /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]); |
| /// assert_eq!(vec2, []); |
| /// ``` |
| #[inline] |
| #[stable(feature = "append", since = "1.4.0")] |
| pub fn append(&mut self, other: &mut Self) { |
| self.reserve(other.len()); |
| let len = self.len(); |
| unsafe { |
| ptr::copy_nonoverlapping(other.as_ptr(), self.get_unchecked_mut(len), other.len()); |
| } |
| |
| self.len += other.len(); |
| unsafe { |
| other.set_len(0); |
| } |
| } |
| |
| /// Create a draining iterator that removes the specified range in the vector |
| /// and yields the removed items. |
| /// |
| /// Note 1: The element range is removed even if the iterator is not |
| /// consumed until the end. |
| /// |
| /// Note 2: It is unspecified how many elements are removed from the vector, |
| /// if the `Drain` value is leaked. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the starting point is greater than the end point or if |
| /// the end point is greater than the length of the vector. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = vec![1, 2, 3]; |
| /// let u: Vec<_> = v.drain(1..).collect(); |
| /// assert_eq!(v, &[1]); |
| /// assert_eq!(u, &[2, 3]); |
| /// |
| /// // A full range clears the vector |
| /// v.drain(..); |
| /// assert_eq!(v, &[]); |
| /// ``` |
| #[stable(feature = "drain", since = "1.6.0")] |
| pub fn drain<R>(&mut self, range: R) -> Drain<T> |
| where R: RangeArgument<usize> |
| { |
| // Memory safety |
| // |
| // When the Drain is first created, it shortens the length of |
| // the source vector to make sure no uninitalized or moved-from elements |
| // are accessible at all if the Drain's destructor never gets to run. |
| // |
| // Drain will ptr::read out the values to remove. |
| // When finished, remaining tail of the vec is copied back to cover |
| // the hole, and the vector length is restored to the new length. |
| // |
| let len = self.len(); |
| let start = *range.start().unwrap_or(&0); |
| let end = *range.end().unwrap_or(&len); |
| assert!(start <= end); |
| assert!(end <= len); |
| |
| unsafe { |
| // set self.vec length's to start, to be safe in case Drain is leaked |
| self.set_len(start); |
| // Use the borrow in the IterMut to indicate borrowing behavior of the |
| // whole Drain iterator (like &mut T). |
| let range_slice = slice::from_raw_parts_mut(self.as_mut_ptr().offset(start as isize), |
| end - start); |
| Drain { |
| tail_start: end, |
| tail_len: len - end, |
| iter: range_slice.iter(), |
| vec: Shared::new(self as *mut _), |
| } |
| } |
| } |
| |
| /// Clears the vector, removing all values. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = vec![1, 2, 3]; |
| /// |
| /// v.clear(); |
| /// |
| /// assert!(v.is_empty()); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn clear(&mut self) { |
| self.truncate(0) |
| } |
| |
| /// Returns the number of elements in the vector. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let a = vec![1, 2, 3]; |
| /// assert_eq!(a.len(), 3); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn len(&self) -> usize { |
| self.len |
| } |
| |
| /// Returns `true` if the vector contains no elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = Vec::new(); |
| /// assert!(v.is_empty()); |
| /// |
| /// v.push(1); |
| /// assert!(!v.is_empty()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn is_empty(&self) -> bool { |
| self.len() == 0 |
| } |
| |
| /// Splits the collection into two at the given index. |
| /// |
| /// Returns a newly allocated `Self`. `self` contains elements `[0, at)`, |
| /// and the returned `Self` contains elements `[at, len)`. |
| /// |
| /// Note that the capacity of `self` does not change. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `at > len`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1,2,3]; |
| /// let vec2 = vec.split_off(1); |
| /// assert_eq!(vec, [1]); |
| /// assert_eq!(vec2, [2, 3]); |
| /// ``` |
| #[inline] |
| #[stable(feature = "split_off", since = "1.4.0")] |
| pub fn split_off(&mut self, at: usize) -> Self { |
| assert!(at <= self.len(), "`at` out of bounds"); |
| |
| let other_len = self.len - at; |
| let mut other = Vec::with_capacity(other_len); |
| |
| // Unsafely `set_len` and copy items to `other`. |
| unsafe { |
| self.set_len(at); |
| other.set_len(other_len); |
| |
| ptr::copy_nonoverlapping(self.as_ptr().offset(at as isize), |
| other.as_mut_ptr(), |
| other.len()); |
| } |
| other |
| } |
| } |
| |
| impl<T: Clone> Vec<T> { |
| /// Resizes the `Vec` in-place so that `len()` is equal to `new_len`. |
| /// |
| /// If `new_len` is greater than `len()`, the `Vec` is extended by the |
| /// difference, with each additional slot filled with `value`. |
| /// If `new_len` is less than `len()`, the `Vec` is simply truncated. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec!["hello"]; |
| /// vec.resize(3, "world"); |
| /// assert_eq!(vec, ["hello", "world", "world"]); |
| /// |
| /// let mut vec = vec![1, 2, 3, 4]; |
| /// vec.resize(2, 0); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| #[stable(feature = "vec_resize", since = "1.5.0")] |
| pub fn resize(&mut self, new_len: usize, value: T) { |
| let len = self.len(); |
| |
| if new_len > len { |
| self.extend_with_element(new_len - len, value); |
| } else { |
| self.truncate(new_len); |
| } |
| } |
| |
| /// Extend the vector by `n` additional clones of `value`. |
| fn extend_with_element(&mut self, n: usize, value: T) { |
| self.reserve(n); |
| |
| unsafe { |
| let len = self.len(); |
| let mut ptr = self.as_mut_ptr().offset(len as isize); |
| // Write all elements except the last one |
| for i in 1..n { |
| ptr::write(ptr, value.clone()); |
| ptr = ptr.offset(1); |
| // Increment the length in every step in case clone() panics |
| self.set_len(len + i); |
| } |
| |
| if n > 0 { |
| // We can write the last element directly without cloning needlessly |
| ptr::write(ptr, value); |
| self.set_len(len + n); |
| } |
| } |
| } |
| |
| /// Clones and appends all elements in a slice to the `Vec`. |
| /// |
| /// Iterates over the slice `other`, clones each element, and then appends |
| /// it to this `Vec`. The `other` vector is traversed in-order. |
| /// |
| /// Note that this function is same as `extend` except that it is |
| /// specialized to work with slices instead. If and when Rust gets |
| /// specialization this function will likely be deprecated (but still |
| /// available). |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1]; |
| /// vec.extend_from_slice(&[2, 3, 4]); |
| /// assert_eq!(vec, [1, 2, 3, 4]); |
| /// ``` |
| #[stable(feature = "vec_extend_from_slice", since = "1.6.0")] |
| pub fn extend_from_slice(&mut self, other: &[T]) { |
| self.reserve(other.len()); |
| |
| for i in 0..other.len() { |
| let len = self.len(); |
| |
| // Unsafe code so this can be optimised to a memcpy (or something |
| // similarly fast) when T is Copy. LLVM is easily confused, so any |
| // extra operations during the loop can prevent this optimisation. |
| unsafe { |
| ptr::write(self.get_unchecked_mut(len), other.get_unchecked(i).clone()); |
| self.set_len(len + 1); |
| } |
| } |
| } |
| } |
| |
| impl<T: PartialEq> Vec<T> { |
| /// Removes consecutive repeated elements in the vector. |
| /// |
| /// If the vector is sorted, this removes all duplicates. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut vec = vec![1, 2, 2, 3, 2]; |
| /// |
| /// vec.dedup(); |
| /// |
| /// assert_eq!(vec, [1, 2, 3, 2]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn dedup(&mut self) { |
| unsafe { |
| // Although we have a mutable reference to `self`, we cannot make |
| // *arbitrary* changes. The `PartialEq` comparisons could panic, so we |
| // must ensure that the vector is in a valid state at all time. |
| // |
| // The way that we handle this is by using swaps; we iterate |
| // over all the elements, swapping as we go so that at the end |
| // the elements we wish to keep are in the front, and those we |
| // wish to reject are at the back. We can then truncate the |
| // vector. This operation is still O(n). |
| // |
| // Example: We start in this state, where `r` represents "next |
| // read" and `w` represents "next_write`. |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing self[r] against self[w-1], this is not a duplicate, so |
| // we swap self[r] and self[w] (no effect as r==w) and then increment both |
| // r and w, leaving us with: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing self[r] against self[w-1], this value is a duplicate, |
| // so we increment `r` but leave everything else unchanged: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing self[r] against self[w-1], this is not a duplicate, |
| // so swap self[r] and self[w] and advance r and w: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 2 | 1 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Not a duplicate, repeat: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 2 | 3 | 1 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Duplicate, advance r. End of vec. Truncate to w. |
| |
| let ln = self.len(); |
| if ln <= 1 { |
| return; |
| } |
| |
| // Avoid bounds checks by using raw pointers. |
| let p = self.as_mut_ptr(); |
| let mut r: usize = 1; |
| let mut w: usize = 1; |
| |
| while r < ln { |
| let p_r = p.offset(r as isize); |
| let p_wm1 = p.offset((w - 1) as isize); |
| if *p_r != *p_wm1 { |
| if r != w { |
| let p_w = p_wm1.offset(1); |
| mem::swap(&mut *p_r, &mut *p_w); |
| } |
| w += 1; |
| } |
| r += 1; |
| } |
| |
| self.truncate(w); |
| } |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Internal methods and functions |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| #[doc(hidden)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> { |
| let mut v = Vec::with_capacity(n); |
| v.extend_with_element(n, elem); |
| v |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Common trait implementations for Vec |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Clone> Clone for Vec<T> { |
| #[cfg(not(test))] |
| fn clone(&self) -> Vec<T> { |
| <[T]>::to_vec(&**self) |
| } |
| |
| // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is |
| // required for this method definition, is not available. Instead use the |
| // `slice::to_vec` function which is only available with cfg(test) |
| // NB see the slice::hack module in slice.rs for more information |
| #[cfg(test)] |
| fn clone(&self) -> Vec<T> { |
| ::slice::to_vec(&**self) |
| } |
| |
| fn clone_from(&mut self, other: &Vec<T>) { |
| // drop anything in self that will not be overwritten |
| self.truncate(other.len()); |
| let len = self.len(); |
| |
| // reuse the contained values' allocations/resources. |
| self.clone_from_slice(&other[..len]); |
| |
| // self.len <= other.len due to the truncate above, so the |
| // slice here is always in-bounds. |
| self.extend_from_slice(&other[len..]); |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Hash> Hash for Vec<T> { |
| #[inline] |
| fn hash<H: hash::Hasher>(&self, state: &mut H) { |
| Hash::hash(&**self, state) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Index<usize> for Vec<T> { |
| type Output = T; |
| |
| #[inline] |
| fn index(&self, index: usize) -> &T { |
| // NB built-in indexing via `&[T]` |
| &(**self)[index] |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> IndexMut<usize> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: usize) -> &mut T { |
| // NB built-in indexing via `&mut [T]` |
| &mut (**self)[index] |
| } |
| } |
| |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::Index<ops::Range<usize>> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, index: ops::Range<usize>) -> &[T] { |
| Index::index(&**self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::Index<ops::RangeTo<usize>> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, index: ops::RangeTo<usize>) -> &[T] { |
| Index::index(&**self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::Index<ops::RangeFrom<usize>> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, index: ops::RangeFrom<usize>) -> &[T] { |
| Index::index(&**self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::Index<ops::RangeFull> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, _index: ops::RangeFull) -> &[T] { |
| self |
| } |
| } |
| #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
| impl<T> ops::Index<ops::RangeInclusive<usize>> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, index: ops::RangeInclusive<usize>) -> &[T] { |
| Index::index(&**self, index) |
| } |
| } |
| #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
| impl<T> ops::Index<ops::RangeToInclusive<usize>> for Vec<T> { |
| type Output = [T]; |
| |
| #[inline] |
| fn index(&self, index: ops::RangeToInclusive<usize>) -> &[T] { |
| Index::index(&**self, index) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::IndexMut<ops::Range<usize>> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [T] { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::IndexMut<ops::RangeTo<usize>> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut [T] { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::IndexMut<ops::RangeFrom<usize>> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut [T] { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::IndexMut<ops::RangeFull> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, _index: ops::RangeFull) -> &mut [T] { |
| self |
| } |
| } |
| #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
| impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut [T] { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] |
| impl<T> ops::IndexMut<ops::RangeToInclusive<usize>> for Vec<T> { |
| #[inline] |
| fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut [T] { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::Deref for Vec<T> { |
| type Target = [T]; |
| |
| fn deref(&self) -> &[T] { |
| unsafe { |
| let p = self.buf.ptr(); |
| assume(!p.is_null()); |
| slice::from_raw_parts(p, self.len) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ops::DerefMut for Vec<T> { |
| fn deref_mut(&mut self) -> &mut [T] { |
| unsafe { |
| let ptr = self.buf.ptr(); |
| assume(!ptr.is_null()); |
| slice::from_raw_parts_mut(ptr, self.len) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> FromIterator<T> for Vec<T> { |
| #[inline] |
| fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Vec<T> { |
| // Unroll the first iteration, as the vector is going to be |
| // expanded on this iteration in every case when the iterable is not |
| // empty, but the loop in extend_desugared() is not going to see the |
| // vector being full in the few subsequent loop iterations. |
| // So we get better branch prediction. |
| let mut iterator = iter.into_iter(); |
| let mut vector = match iterator.next() { |
| None => return Vec::new(), |
| Some(element) => { |
| let (lower, _) = iterator.size_hint(); |
| let mut vector = Vec::with_capacity(lower.saturating_add(1)); |
| unsafe { |
| ptr::write(vector.get_unchecked_mut(0), element); |
| vector.set_len(1); |
| } |
| vector |
| } |
| }; |
| vector.extend_desugared(iterator); |
| vector |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> IntoIterator for Vec<T> { |
| type Item = T; |
| type IntoIter = IntoIter<T>; |
| |
| /// Creates a consuming iterator, that is, one that moves each value out of |
| /// the vector (from start to end). The vector cannot be used after calling |
| /// this. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let v = vec!["a".to_string(), "b".to_string()]; |
| /// for s in v.into_iter() { |
| /// // s has type String, not &String |
| /// println!("{}", s); |
| /// } |
| /// ``` |
| #[inline] |
| fn into_iter(mut self) -> IntoIter<T> { |
| unsafe { |
| let ptr = self.as_mut_ptr(); |
| assume(!ptr.is_null()); |
| let begin = ptr as *const T; |
| let end = if mem::size_of::<T>() == 0 { |
| arith_offset(ptr as *const i8, self.len() as isize) as *const T |
| } else { |
| ptr.offset(self.len() as isize) as *const T |
| }; |
| let buf = ptr::read(&self.buf); |
| mem::forget(self); |
| IntoIter { |
| _buf: buf, |
| ptr: begin, |
| end: end, |
| } |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> IntoIterator for &'a Vec<T> { |
| type Item = &'a T; |
| type IntoIter = slice::Iter<'a, T>; |
| |
| fn into_iter(self) -> slice::Iter<'a, T> { |
| self.iter() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> IntoIterator for &'a mut Vec<T> { |
| type Item = &'a mut T; |
| type IntoIter = slice::IterMut<'a, T>; |
| |
| fn into_iter(mut self) -> slice::IterMut<'a, T> { |
| self.iter_mut() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Extend<T> for Vec<T> { |
| #[inline] |
| fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { |
| <Self as SpecExtend<I>>::spec_extend(self, iter); |
| } |
| } |
| |
| impl<I: IntoIterator> SpecExtend<I> for Vec<I::Item> { |
| default fn spec_extend(&mut self, iter: I) { |
| self.extend_desugared(iter.into_iter()) |
| } |
| } |
| |
| impl<T> SpecExtend<Vec<T>> for Vec<T> { |
| fn spec_extend(&mut self, ref mut other: Vec<T>) { |
| self.append(other); |
| } |
| } |
| |
| impl<T> Vec<T> { |
| fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) { |
| // This function should be the moral equivalent of: |
| // |
| // for item in iterator { |
| // self.push(item); |
| // } |
| while let Some(element) = iterator.next() { |
| let len = self.len(); |
| if len == self.capacity() { |
| let (lower, _) = iterator.size_hint(); |
| self.reserve(lower.saturating_add(1)); |
| } |
| unsafe { |
| ptr::write(self.get_unchecked_mut(len), element); |
| // NB can't overflow since we would have had to alloc the address space |
| self.set_len(len + 1); |
| } |
| } |
| } |
| } |
| |
| #[stable(feature = "extend_ref", since = "1.2.0")] |
| impl<'a, T: 'a + Copy> Extend<&'a T> for Vec<T> { |
| fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
| self.extend(iter.into_iter().cloned()); |
| } |
| } |
| |
| macro_rules! __impl_slice_eq1 { |
| ($Lhs: ty, $Rhs: ty) => { |
| __impl_slice_eq1! { $Lhs, $Rhs, Sized } |
| }; |
| ($Lhs: ty, $Rhs: ty, $Bound: ident) => { |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> { |
| #[inline] |
| fn eq(&self, other: &$Rhs) -> bool { self[..] == other[..] } |
| #[inline] |
| fn ne(&self, other: &$Rhs) -> bool { self[..] != other[..] } |
| } |
| } |
| } |
| |
| __impl_slice_eq1! { Vec<A>, Vec<B> } |
| __impl_slice_eq1! { Vec<A>, &'b [B] } |
| __impl_slice_eq1! { Vec<A>, &'b mut [B] } |
| __impl_slice_eq1! { Cow<'a, [A]>, &'b [B], Clone } |
| __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B], Clone } |
| __impl_slice_eq1! { Cow<'a, [A]>, Vec<B>, Clone } |
| |
| macro_rules! array_impls { |
| ($($N: expr)+) => { |
| $( |
| // NOTE: some less important impls are omitted to reduce code bloat |
| __impl_slice_eq1! { Vec<A>, [B; $N] } |
| __impl_slice_eq1! { Vec<A>, &'b [B; $N] } |
| // __impl_slice_eq1! { Vec<A>, &'b mut [B; $N] } |
| // __impl_slice_eq1! { Cow<'a, [A]>, [B; $N], Clone } |
| // __impl_slice_eq1! { Cow<'a, [A]>, &'b [B; $N], Clone } |
| // __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B; $N], Clone } |
| )+ |
| } |
| } |
| |
| array_impls! { |
| 0 1 2 3 4 5 6 7 8 9 |
| 10 11 12 13 14 15 16 17 18 19 |
| 20 21 22 23 24 25 26 27 28 29 |
| 30 31 32 |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: PartialOrd> PartialOrd for Vec<T> { |
| #[inline] |
| fn partial_cmp(&self, other: &Vec<T>) -> Option<Ordering> { |
| PartialOrd::partial_cmp(&**self, &**other) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Eq> Eq for Vec<T> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Ord> Ord for Vec<T> { |
| #[inline] |
| fn cmp(&self, other: &Vec<T>) -> Ordering { |
| Ord::cmp(&**self, &**other) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Drop for Vec<T> { |
| #[unsafe_destructor_blind_to_params] |
| fn drop(&mut self) { |
| if self.buf.unsafe_no_drop_flag_needs_drop() { |
| unsafe { |
| // use drop for [T] |
| ptr::drop_in_place(&mut self[..]); |
| } |
| } |
| // RawVec handles deallocation |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Default for Vec<T> { |
| fn default() -> Vec<T> { |
| Vec::new() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: fmt::Debug> fmt::Debug for Vec<T> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| fmt::Debug::fmt(&**self, f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> AsRef<Vec<T>> for Vec<T> { |
| fn as_ref(&self) -> &Vec<T> { |
| self |
| } |
| } |
| |
| #[stable(feature = "vec_as_mut", since = "1.5.0")] |
| impl<T> AsMut<Vec<T>> for Vec<T> { |
| fn as_mut(&mut self) -> &mut Vec<T> { |
| self |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> AsRef<[T]> for Vec<T> { |
| fn as_ref(&self) -> &[T] { |
| self |
| } |
| } |
| |
| #[stable(feature = "vec_as_mut", since = "1.5.0")] |
| impl<T> AsMut<[T]> for Vec<T> { |
| fn as_mut(&mut self) -> &mut [T] { |
| self |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T: Clone> From<&'a [T]> for Vec<T> { |
| #[cfg(not(test))] |
| fn from(s: &'a [T]) -> Vec<T> { |
| s.to_vec() |
| } |
| #[cfg(test)] |
| fn from(s: &'a [T]) -> Vec<T> { |
| ::slice::to_vec(s) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a> From<&'a str> for Vec<u8> { |
| fn from(s: &'a str) -> Vec<u8> { |
| From::from(s.as_bytes()) |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Clone-on-write |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| #[stable(feature = "cow_from_vec", since = "1.7.0")] |
| impl<'a, T: Clone> From<&'a [T]> for Cow<'a, [T]> { |
| fn from(s: &'a [T]) -> Cow<'a, [T]> { |
| Cow::Borrowed(s) |
| } |
| } |
| |
| #[stable(feature = "cow_from_vec", since = "1.7.0")] |
| impl<'a, T: Clone> From<Vec<T>> for Cow<'a, [T]> { |
| fn from(v: Vec<T>) -> Cow<'a, [T]> { |
| Cow::Owned(v) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> FromIterator<T> for Cow<'a, [T]> where T: Clone { |
| fn from_iter<I: IntoIterator<Item = T>>(it: I) -> Cow<'a, [T]> { |
| Cow::Owned(FromIterator::from_iter(it)) |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Iterators |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| /// An iterator that moves out of a vector. |
| /// |
| /// This `struct` is created by the `into_iter` method on [`Vec`][`Vec`] (provided |
| /// by the [`IntoIterator`] trait). |
| /// |
| /// [`Vec`]: struct.Vec.html |
| /// [`IntoIterator`]: ../../std/iter/trait.IntoIterator.html |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct IntoIter<T> { |
| _buf: RawVec<T>, |
| ptr: *const T, |
| end: *const T, |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| unsafe impl<T: Send> Send for IntoIter<T> {} |
| #[stable(feature = "rust1", since = "1.0.0")] |
| unsafe impl<T: Sync> Sync for IntoIter<T> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Iterator for IntoIter<T> { |
| type Item = T; |
| |
| #[inline] |
| fn next(&mut self) -> Option<T> { |
| unsafe { |
| if self.ptr == self.end { |
| None |
| } else { |
| if mem::size_of::<T>() == 0 { |
| // purposefully don't use 'ptr.offset' because for |
| // vectors with 0-size elements this would return the |
| // same pointer. |
| self.ptr = arith_offset(self.ptr as *const i8, 1) as *const T; |
| |
| // Use a non-null pointer value |
| Some(ptr::read(EMPTY as *mut T)) |
| } else { |
| let old = self.ptr; |
| self.ptr = self.ptr.offset(1); |
| |
| Some(ptr::read(old)) |
| } |
| } |
| } |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| let diff = (self.end as usize) - (self.ptr as usize); |
| let size = mem::size_of::<T>(); |
| let exact = diff / |
| (if size == 0 { |
| 1 |
| } else { |
| size |
| }); |
| (exact, Some(exact)) |
| } |
| |
| #[inline] |
| fn count(self) -> usize { |
| self.len() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> DoubleEndedIterator for IntoIter<T> { |
| #[inline] |
| fn next_back(&mut self) -> Option<T> { |
| unsafe { |
| if self.end == self.ptr { |
| None |
| } else { |
| if mem::size_of::<T>() == 0 { |
| // See above for why 'ptr.offset' isn't used |
| self.end = arith_offset(self.end as *const i8, -1) as *const T; |
| |
| // Use a non-null pointer value |
| Some(ptr::read(EMPTY as *mut T)) |
| } else { |
| self.end = self.end.offset(-1); |
| |
| Some(ptr::read(self.end)) |
| } |
| } |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> ExactSizeIterator for IntoIter<T> {} |
| |
| #[stable(feature = "vec_into_iter_clone", since = "1.8.0")] |
| impl<T: Clone> Clone for IntoIter<T> { |
| fn clone(&self) -> IntoIter<T> { |
| unsafe { |
| slice::from_raw_parts(self.ptr, self.len()).to_owned().into_iter() |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Drop for IntoIter<T> { |
| #[unsafe_destructor_blind_to_params] |
| fn drop(&mut self) { |
| // destroy the remaining elements |
| for _x in self {} |
| |
| // RawVec handles deallocation |
| } |
| } |
| |
| /// A draining iterator for `Vec<T>`. |
| /// |
| /// This `struct` is created by the [`drain`] method on [`Vec`]. |
| /// |
| /// [`drain`]: struct.Vec.html#method.drain |
| /// [`Vec`]: struct.Vec.html |
| #[stable(feature = "drain", since = "1.6.0")] |
| pub struct Drain<'a, T: 'a> { |
| /// Index of tail to preserve |
| tail_start: usize, |
| /// Length of tail |
| tail_len: usize, |
| /// Current remaining range to remove |
| iter: slice::Iter<'a, T>, |
| vec: Shared<Vec<T>>, |
| } |
| |
| #[stable(feature = "drain", since = "1.6.0")] |
| unsafe impl<'a, T: Sync> Sync for Drain<'a, T> {} |
| #[stable(feature = "drain", since = "1.6.0")] |
| unsafe impl<'a, T: Send> Send for Drain<'a, T> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> Iterator for Drain<'a, T> { |
| type Item = T; |
| |
| #[inline] |
| fn next(&mut self) -> Option<T> { |
| self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) }) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.iter.size_hint() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> DoubleEndedIterator for Drain<'a, T> { |
| #[inline] |
| fn next_back(&mut self) -> Option<T> { |
| self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) }) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> Drop for Drain<'a, T> { |
| fn drop(&mut self) { |
| // exhaust self first |
| while let Some(_) = self.next() {} |
| |
| if self.tail_len > 0 { |
| unsafe { |
| let source_vec = &mut **self.vec; |
| // memmove back untouched tail, update to new length |
| let start = source_vec.len(); |
| let tail = self.tail_start; |
| let src = source_vec.as_ptr().offset(tail as isize); |
| let dst = source_vec.as_mut_ptr().offset(start as isize); |
| ptr::copy(src, dst, self.tail_len); |
| source_vec.set_len(start + self.tail_len); |
| } |
| } |
| } |
| } |
| |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> ExactSizeIterator for Drain<'a, T> {} |
