a3b19c8858
When things get stabilized, they don't always have their docs updated to remove the gate.
2026 lines
63 KiB
Rust
2026 lines
63 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A growable list type with heap-allocated contents, written `Vec<T>` but
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//! pronounced 'vector.'
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//!
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//! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and
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//! `O(1)` pop (from the end).
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//!
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//! # Examples
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//!
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//! You can explicitly create a `Vec<T>` with `new()`:
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//!
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//! ```
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//! let v: Vec<i32> = Vec::new();
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//! ```
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//!
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//! ...or by using the `vec!` macro:
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//!
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//! ```
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//! let v: Vec<i32> = vec![];
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//!
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//! let v = vec![1, 2, 3, 4, 5];
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//!
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//! let v = vec![0; 10]; // ten zeroes
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//! ```
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//!
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//! You can `push` values onto the end of a vector (which will grow the vector as needed):
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//!
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//! ```
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//! let mut v = vec![1, 2];
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//!
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//! v.push(3);
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//! ```
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//!
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//! Popping values works in much the same way:
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//!
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//! ```
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//! let mut v = vec![1, 2];
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//!
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//! let two = v.pop();
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//! ```
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//!
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//! Vectors also support indexing (through the `Index` and `IndexMut` traits):
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//!
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//! ```
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//! let mut v = vec![1, 2, 3];
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//! let three = v[2];
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//! v[1] = v[1] + 5;
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//! ```
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#![stable(feature = "rust1", since = "1.0.0")]
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use core::prelude::*;
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use alloc::boxed::Box;
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use alloc::heap::{EMPTY, allocate, reallocate, deallocate};
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use core::cmp::max;
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use core::cmp::Ordering;
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use core::fmt;
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use core::hash::{self, Hash};
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use core::intrinsics::{arith_offset, assume};
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use core::iter::{repeat, FromIterator};
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use core::marker::PhantomData;
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use core::mem;
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use core::ops::{Index, IndexMut, Deref};
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use core::ops;
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use core::ptr;
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use core::ptr::Unique;
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use core::slice;
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use core::isize;
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use core::usize;
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use borrow::{Cow, IntoCow};
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use super::range::RangeArgument;
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// FIXME- fix places which assume the max vector allowed has memory usize::MAX.
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static MAX_MEMORY_SIZE: usize = isize::MAX as usize;
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/// A growable list type, written `Vec<T>` but pronounced 'vector.'
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = Vec::new();
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/// vec.push(1);
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/// vec.push(2);
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///
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/// assert_eq!(vec.len(), 2);
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/// assert_eq!(vec[0], 1);
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///
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/// assert_eq!(vec.pop(), Some(2));
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/// assert_eq!(vec.len(), 1);
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///
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/// vec[0] = 7;
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/// assert_eq!(vec[0], 7);
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///
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/// vec.extend([1, 2, 3].iter().cloned());
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///
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/// for x in &vec {
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/// println!("{}", x);
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/// }
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/// assert_eq!(vec, [7, 1, 2, 3]);
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/// ```
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///
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/// The `vec!` macro is provided to make initialization more convenient:
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///
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/// ```
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/// let mut vec = vec![1, 2, 3];
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/// vec.push(4);
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/// assert_eq!(vec, [1, 2, 3, 4]);
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/// ```
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///
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/// Use a `Vec<T>` as an efficient stack:
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///
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/// ```
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/// let mut stack = Vec::new();
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///
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/// stack.push(1);
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/// stack.push(2);
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/// stack.push(3);
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///
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/// while let Some(top) = stack.pop() {
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/// // Prints 3, 2, 1
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/// println!("{}", top);
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/// }
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/// ```
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///
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/// # Capacity and reallocation
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///
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/// The capacity of a vector is the amount of space allocated for any future
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/// elements that will be added onto the vector. This is not to be confused with
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/// the *length* of a vector, which specifies the number of actual elements
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/// within the vector. If a vector's length exceeds its capacity, its capacity
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/// will automatically be increased, but its elements will have to be
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/// reallocated.
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///
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/// For example, a vector with capacity 10 and length 0 would be an empty vector
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/// with space for 10 more elements. Pushing 10 or fewer elements onto the
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/// vector will not change its capacity or cause reallocation to occur. However,
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/// if the vector's length is increased to 11, it will have to reallocate, which
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/// can be slow. For this reason, it is recommended to use `Vec::with_capacity`
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/// whenever possible to specify how big the vector is expected to get.
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#[unsafe_no_drop_flag]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Vec<T> {
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ptr: Unique<T>,
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len: usize,
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cap: usize,
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}
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unsafe impl<T: Send> Send for Vec<T> { }
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unsafe impl<T: Sync> Sync for Vec<T> { }
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////////////////////////////////////////////////////////////////////////////////
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// Inherent methods
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////////////////////////////////////////////////////////////////////////////////
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impl<T> Vec<T> {
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/// Constructs a new, empty `Vec<T>`.
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///
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/// The vector will not allocate until elements are pushed onto it.
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///
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/// # Examples
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///
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/// ```
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/// let mut vec: Vec<i32> = Vec::new();
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> Vec<T> {
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// We want ptr to never be NULL so instead we set it to some arbitrary
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// non-null value which is fine since we never call deallocate on the ptr
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// if cap is 0. The reason for this is because the pointer of a slice
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// being NULL would break the null pointer optimization for enums.
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unsafe { Vec::from_raw_parts(EMPTY as *mut T, 0, 0) }
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}
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/// Constructs a new, empty `Vec<T>` with the specified capacity.
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///
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/// The vector will be able to hold exactly `capacity` elements without reallocating. If
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/// `capacity` is 0, the vector will not allocate.
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///
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/// It is important to note that this function does not specify the *length* of the returned
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/// vector, but only the *capacity*. (For an explanation of the difference between length and
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/// capacity, see the main `Vec<T>` docs above, 'Capacity and reallocation'.)
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = Vec::with_capacity(10);
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///
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/// // The vector contains no items, even though it has capacity for more
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/// assert_eq!(vec.len(), 0);
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///
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/// // These are all done without reallocating...
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/// for i in 0..10 {
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/// vec.push(i);
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/// }
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///
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/// // ...but this may make the vector reallocate
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/// vec.push(11);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn with_capacity(capacity: usize) -> Vec<T> {
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if mem::size_of::<T>() == 0 {
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unsafe { Vec::from_raw_parts(EMPTY as *mut T, 0, usize::MAX) }
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} else if capacity == 0 {
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Vec::new()
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} else {
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let size = capacity.checked_mul(mem::size_of::<T>())
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.expect("capacity overflow");
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let ptr = unsafe { allocate(size, mem::min_align_of::<T>()) };
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if ptr.is_null() { ::alloc::oom() }
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unsafe { Vec::from_raw_parts(ptr as *mut T, 0, capacity) }
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}
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}
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/// Creates a `Vec<T>` directly from the raw components of another vector.
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///
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/// This is highly unsafe, due to the number of invariants that aren't checked.
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///
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/// # Examples
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///
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/// ```
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/// use std::ptr;
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/// use std::mem;
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///
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/// fn main() {
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/// let mut v = vec![1, 2, 3];
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///
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/// // Pull out the various important pieces of information about `v`
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/// let p = v.as_mut_ptr();
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/// let len = v.len();
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/// let cap = v.capacity();
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///
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/// unsafe {
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/// // Cast `v` into the void: no destructor run, so we are in
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/// // complete control of the allocation to which `p` points.
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/// mem::forget(v);
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///
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/// // Overwrite memory with 4, 5, 6
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/// for i in 0..len as isize {
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/// ptr::write(p.offset(i), 4 + i);
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/// }
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///
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/// // Put everything back together into a Vec
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/// let rebuilt = Vec::from_raw_parts(p, len, cap);
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/// assert_eq!(rebuilt, [4, 5, 6]);
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/// }
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub unsafe fn from_raw_parts(ptr: *mut T, length: usize,
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capacity: usize) -> Vec<T> {
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Vec {
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ptr: Unique::new(ptr),
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len: length,
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cap: capacity,
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}
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}
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/// Creates a vector by copying the elements from a raw pointer.
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///
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/// This function will copy `elts` contiguous elements starting at `ptr`
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/// into a new allocation owned by the returned `Vec<T>`. The elements of
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/// the buffer are copied into the vector without cloning, as if
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/// `ptr::read()` were called on them.
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#[inline]
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#[unstable(feature = "collections",
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reason = "may be better expressed via composition")]
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pub unsafe fn from_raw_buf(ptr: *const T, elts: usize) -> Vec<T> {
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let mut dst = Vec::with_capacity(elts);
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dst.set_len(elts);
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ptr::copy_nonoverlapping(ptr, dst.as_mut_ptr(), elts);
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dst
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}
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/// Returns the number of elements the vector can hold without
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/// reallocating.
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///
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/// # Examples
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///
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/// ```
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/// let vec: Vec<i32> = Vec::with_capacity(10);
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/// assert_eq!(vec.capacity(), 10);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn capacity(&self) -> usize {
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self.cap
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}
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/// Reserves capacity for at least `additional` more elements to be inserted
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/// in the given `Vec<T>`. The collection may reserve more space to avoid
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/// frequent reallocations.
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///
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/// # Panics
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///
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/// Panics if the new capacity overflows `usize`.
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = vec![1];
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/// vec.reserve(10);
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/// assert!(vec.capacity() >= 11);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn reserve(&mut self, additional: usize) {
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if self.cap - self.len < additional {
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const ERR_MSG: &'static str = "Vec::reserve: `isize` overflow";
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let new_min_cap = self.len.checked_add(additional).expect(ERR_MSG);
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if new_min_cap > MAX_MEMORY_SIZE { panic!(ERR_MSG) }
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self.grow_capacity(match new_min_cap.checked_next_power_of_two() {
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Some(x) if x > MAX_MEMORY_SIZE => MAX_MEMORY_SIZE,
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None => MAX_MEMORY_SIZE,
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Some(x) => x,
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});
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}
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}
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/// Reserves the minimum capacity for exactly `additional` more elements to
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/// be inserted in the given `Vec<T>`. Does nothing if the capacity is already
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/// sufficient.
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///
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/// Note that the allocator may give the collection more space than it
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/// requests. Therefore capacity can not be relied upon to be precisely
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/// minimal. Prefer `reserve` if future insertions are expected.
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///
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/// # Panics
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///
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/// Panics if the new capacity overflows `usize`.
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = vec![1];
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/// vec.reserve_exact(10);
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/// assert!(vec.capacity() >= 11);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn reserve_exact(&mut self, additional: usize) {
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if self.cap - self.len < additional {
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match self.len.checked_add(additional) {
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None => panic!("Vec::reserve: `usize` overflow"),
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Some(new_cap) => self.grow_capacity(new_cap)
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}
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}
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}
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/// Shrinks the capacity of the vector as much as possible.
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///
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/// It will drop down as close as possible to the length but the allocator
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/// may still inform the vector that there is space for a few more elements.
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = Vec::with_capacity(10);
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/// vec.extend([1, 2, 3].iter().cloned());
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/// assert_eq!(vec.capacity(), 10);
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/// vec.shrink_to_fit();
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/// assert!(vec.capacity() >= 3);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn shrink_to_fit(&mut self) {
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if mem::size_of::<T>() == 0 { return }
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if self.len == 0 {
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if self.cap != 0 {
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unsafe {
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dealloc(*self.ptr, self.cap)
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}
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self.cap = 0;
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}
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} else if self.cap != self.len {
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unsafe {
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// Overflow check is unnecessary as the vector is already at
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// least this large.
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let ptr = reallocate(*self.ptr as *mut u8,
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self.cap * mem::size_of::<T>(),
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self.len * mem::size_of::<T>(),
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mem::min_align_of::<T>()) as *mut T;
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if ptr.is_null() { ::alloc::oom() }
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self.ptr = Unique::new(ptr);
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}
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self.cap = self.len;
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}
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}
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/// Converts the vector into Box<[T]>.
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///
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/// Note that this will drop any excess capacity. Calling this and
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/// converting back to a vector with `into_vec()` is equivalent to calling
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/// `shrink_to_fit()`.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn into_boxed_slice(mut self) -> Box<[T]> {
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self.shrink_to_fit();
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unsafe {
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let xs: Box<[T]> = Box::from_raw(&mut *self);
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mem::forget(self);
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xs
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}
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}
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/// Shorten a vector, dropping excess elements.
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///
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/// If `len` is greater than the vector's current length, this has no
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/// effect.
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///
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/// # Examples
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///
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/// ```
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/// let mut vec = vec![1, 2, 3, 4];
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/// vec.truncate(2);
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/// assert_eq!(vec, [1, 2]);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn truncate(&mut self, len: usize) {
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unsafe {
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// drop any extra elements
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while len < self.len {
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// decrement len before the read(), so a panic on Drop doesn't
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// re-drop the just-failed value.
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self.len -= 1;
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ptr::read(self.get_unchecked(self.len));
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}
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}
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}
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/// Extracts a slice containing the entire vector.
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///
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/// Equivalent to `&s[..]`.
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#[inline]
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#[unstable(feature = "convert",
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reason = "waiting on RFC revision")]
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pub fn as_slice(&self) -> &[T] {
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self
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}
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/// Extracts a mutable slice of the entire vector.
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///
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/// Equivalent to `&mut s[..]`.
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#[inline]
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#[unstable(feature = "convert",
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reason = "waiting on RFC revision")]
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pub fn as_mut_slice(&mut self) -> &mut [T] {
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&mut self[..]
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}
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/// Sets the length of a vector.
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///
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/// This will explicitly set the size of the vector, without actually
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/// modifying its buffers, so it is up to the caller to ensure that the
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/// vector is actually the specified size.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = vec![1, 2, 3, 4];
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/// unsafe {
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/// v.set_len(1);
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/// }
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub unsafe fn set_len(&mut self, len: usize) {
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self.len = len;
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}
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/// Removes an element from anywhere in the vector and return it, replacing
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/// it with the last element.
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///
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/// This does not preserve ordering, but is O(1).
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///
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/// # Panics
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///
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/// Panics if `index` is out of bounds.
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///
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/// # Examples
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///
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/// ```
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/// let mut v = vec!["foo", "bar", "baz", "qux"];
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///
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/// assert_eq!(v.swap_remove(1), "bar");
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/// assert_eq!(v, ["foo", "qux", "baz"]);
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///
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/// assert_eq!(v.swap_remove(0), "foo");
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/// assert_eq!(v, ["baz", "qux"]);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn swap_remove(&mut self, index: usize) -> T {
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let length = self.len();
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self.swap(index, length - 1);
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self.pop().unwrap()
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}
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|
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/// Inserts an element at position `index` within the vector, shifting all
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/// elements after position `i` one position to the right.
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///
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/// # Panics
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///
|
|
/// 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
|
|
self.reserve(1);
|
|
|
|
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(&mut *p, element);
|
|
}
|
|
self.set_len(len + 1);
|
|
}
|
|
}
|
|
|
|
/// Removes and returns the element at position `index` within the vector,
|
|
/// shifting all elements after position `index` one position 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) {
|
|
#[cold]
|
|
#[inline(never)]
|
|
fn resize<T>(vec: &mut Vec<T>) {
|
|
let old_size = vec.cap * mem::size_of::<T>();
|
|
if old_size >= MAX_MEMORY_SIZE { panic!("capacity overflow") }
|
|
let mut size = max(old_size, 2 * mem::size_of::<T>()) * 2;
|
|
if old_size > size || size > MAX_MEMORY_SIZE {
|
|
size = MAX_MEMORY_SIZE;
|
|
}
|
|
unsafe {
|
|
let ptr = alloc_or_realloc(*vec.ptr, old_size, size);
|
|
if ptr.is_null() { ::alloc::oom() }
|
|
vec.ptr = Unique::new(ptr);
|
|
}
|
|
vec.cap = max(vec.cap, 2) * 2;
|
|
}
|
|
|
|
if mem::size_of::<T>() == 0 {
|
|
// zero-size types consume no memory, so we can't rely on the
|
|
// address space running out
|
|
self.len = self.len.checked_add(1).expect("length overflow");
|
|
mem::forget(value);
|
|
return
|
|
}
|
|
|
|
if self.len == self.cap {
|
|
resize(self);
|
|
}
|
|
|
|
unsafe {
|
|
let end = (*self.ptr).offset(self.len as isize);
|
|
ptr::write(&mut *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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// 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]
|
|
#[unstable(feature = "collections",
|
|
reason = "new API, waiting for dust to settle")]
|
|
pub fn append(&mut self, other: &mut Self) {
|
|
if mem::size_of::<T>() == 0 {
|
|
// zero-size types consume no memory, so we can't rely on the
|
|
// address space running out
|
|
self.len = self.len.checked_add(other.len()).expect("length overflow");
|
|
unsafe { other.set_len(0) }
|
|
return;
|
|
}
|
|
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 from start to end. The element range is
|
|
/// removed even if the iterator is not consumed until the end.
|
|
///
|
|
/// Note: 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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections_drain)]
|
|
///
|
|
/// // Draining using `..` clears the whole vector.
|
|
/// let mut v = vec![1, 2, 3];
|
|
/// let u: Vec<_> = v.drain(..).collect();
|
|
/// assert_eq!(v, &[]);
|
|
/// assert_eq!(u, &[1, 2, 3]);
|
|
/// ```
|
|
#[unstable(feature = "collections_drain",
|
|
reason = "recently added, matches RFC")]
|
|
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_mut(),
|
|
vec: 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 }
|
|
|
|
/// Converts a `Vec<T>` to a `Vec<U>` where `T` and `U` have the same
|
|
/// size and in case they are not zero-sized the same minimal alignment.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if `T` and `U` have differing sizes or are not zero-sized and
|
|
/// have differing minimal alignments.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// let v = vec![0, 1, 2];
|
|
/// let w = v.map_in_place(|i| i + 3);
|
|
/// assert_eq!(&w[..], &[3, 4, 5]);
|
|
///
|
|
/// #[derive(PartialEq, Debug)]
|
|
/// struct Newtype(u8);
|
|
/// let bytes = vec![0x11, 0x22];
|
|
/// let newtyped_bytes = bytes.map_in_place(|x| Newtype(x));
|
|
/// assert_eq!(&newtyped_bytes[..], &[Newtype(0x11), Newtype(0x22)]);
|
|
/// ```
|
|
#[unstable(feature = "collections",
|
|
reason = "API may change to provide stronger guarantees")]
|
|
pub fn map_in_place<U, F>(self, mut f: F) -> Vec<U> where F: FnMut(T) -> U {
|
|
// FIXME: Assert statically that the types `T` and `U` have the same
|
|
// size.
|
|
assert!(mem::size_of::<T>() == mem::size_of::<U>());
|
|
|
|
let mut vec = self;
|
|
|
|
if mem::size_of::<T>() != 0 {
|
|
// FIXME: Assert statically that the types `T` and `U` have the
|
|
// same minimal alignment in case they are not zero-sized.
|
|
|
|
// These asserts are necessary because the `min_align_of` of the
|
|
// types are passed to the allocator by `Vec`.
|
|
assert!(mem::min_align_of::<T>() == mem::min_align_of::<U>());
|
|
|
|
// This `as isize` cast is safe, because the size of the elements of the
|
|
// vector is not 0, and:
|
|
//
|
|
// 1) If the size of the elements in the vector is 1, the `isize` may
|
|
// overflow, but it has the correct bit pattern so that the
|
|
// `.offset()` function will work.
|
|
//
|
|
// Example:
|
|
// Address space 0x0-0xF.
|
|
// `u8` array at: 0x1.
|
|
// Size of `u8` array: 0x8.
|
|
// Calculated `offset`: -0x8.
|
|
// After `array.offset(offset)`: 0x9.
|
|
// (0x1 + 0x8 = 0x1 - 0x8)
|
|
//
|
|
// 2) If the size of the elements in the vector is >1, the `usize` ->
|
|
// `isize` conversion can't overflow.
|
|
let offset = vec.len() as isize;
|
|
let start = vec.as_mut_ptr();
|
|
|
|
let mut pv = PartialVecNonZeroSized {
|
|
vec: vec,
|
|
|
|
start_t: start,
|
|
// This points inside the vector, as the vector has length
|
|
// `offset`.
|
|
end_t: unsafe { start.offset(offset) },
|
|
start_u: start as *mut U,
|
|
end_u: start as *mut U,
|
|
|
|
_marker: PhantomData,
|
|
};
|
|
// start_t
|
|
// start_u
|
|
// |
|
|
// +-+-+-+-+-+-+
|
|
// |T|T|T|...|T|
|
|
// +-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
|
|
while pv.end_u as *mut T != pv.end_t {
|
|
unsafe {
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// |U|...|U|T|T|...|T|
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
|
|
let t = ptr::read(pv.start_t);
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// |U|...|U|X|T|...|T|
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
// We must not panic here, one cell is marked as `T`
|
|
// although it is not `T`.
|
|
|
|
pv.start_t = pv.start_t.offset(1);
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// |U|...|U|X|T|...|T|
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
// We may panic again.
|
|
|
|
// The function given by the user might panic.
|
|
let u = f(t);
|
|
|
|
ptr::write(pv.end_u, u);
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// |U|...|U|U|T|...|T|
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
// We should not panic here, because that would leak the `U`
|
|
// pointed to by `end_u`.
|
|
|
|
pv.end_u = pv.end_u.offset(1);
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// |U|...|U|U|T|...|T|
|
|
// +-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// end_u end_t
|
|
// We may panic again.
|
|
}
|
|
}
|
|
|
|
// start_u start_t
|
|
// | |
|
|
// +-+-+-+-+-+-+
|
|
// |U|...|U|U|U|
|
|
// +-+-+-+-+-+-+
|
|
// |
|
|
// end_t
|
|
// end_u
|
|
// Extract `vec` and prevent the destructor of
|
|
// `PartialVecNonZeroSized` from running. Note that none of the
|
|
// function calls can panic, thus no resources can be leaked (as the
|
|
// `vec` member of `PartialVec` is the only one which holds
|
|
// allocations -- and it is returned from this function. None of
|
|
// this can panic.
|
|
unsafe {
|
|
let vec_len = pv.vec.len();
|
|
let vec_cap = pv.vec.capacity();
|
|
let vec_ptr = pv.vec.as_mut_ptr() as *mut U;
|
|
mem::forget(pv);
|
|
Vec::from_raw_parts(vec_ptr, vec_len, vec_cap)
|
|
}
|
|
} else {
|
|
// Put the `Vec` into the `PartialVecZeroSized` structure and
|
|
// prevent the destructor of the `Vec` from running. Since the
|
|
// `Vec` contained zero-sized objects, it did not allocate, so we
|
|
// are not leaking memory here.
|
|
let mut pv = PartialVecZeroSized::<T,U> {
|
|
num_t: vec.len(),
|
|
num_u: 0,
|
|
marker: PhantomData,
|
|
};
|
|
mem::forget(vec);
|
|
|
|
while pv.num_t != 0 {
|
|
unsafe {
|
|
// Create a `T` out of thin air and decrement `num_t`. This
|
|
// must not panic between these steps, as otherwise a
|
|
// destructor of `T` which doesn't exist runs.
|
|
let t = mem::uninitialized();
|
|
pv.num_t -= 1;
|
|
|
|
// The function given by the user might panic.
|
|
let u = f(t);
|
|
|
|
// Forget the `U` and increment `num_u`. This increment
|
|
// cannot overflow the `usize` as we only do this for a
|
|
// number of times that fits into a `usize` (and start with
|
|
// `0`). Again, we should not panic between these steps.
|
|
mem::forget(u);
|
|
pv.num_u += 1;
|
|
}
|
|
}
|
|
// Create a `Vec` from our `PartialVecZeroSized` and make sure the
|
|
// destructor of the latter will not run. None of this can panic.
|
|
let mut result = Vec::new();
|
|
unsafe {
|
|
result.set_len(pv.num_u);
|
|
mem::forget(pv);
|
|
}
|
|
result
|
|
}
|
|
}
|
|
|
|
/// 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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// let mut vec = vec![1,2,3];
|
|
/// let vec2 = vec.split_off(1);
|
|
/// assert_eq!(vec, [1]);
|
|
/// assert_eq!(vec2, [2, 3]);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "collections",
|
|
reason = "new API, waiting for dust to settle")]
|
|
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`.
|
|
///
|
|
/// Calls either `extend()` or `truncate()` depending on whether `new_len`
|
|
/// is larger than the current value of `len()` or not.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// 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]);
|
|
/// ```
|
|
#[unstable(feature = "collections",
|
|
reason = "matches collection reform specification; waiting for dust to settle")]
|
|
pub fn resize(&mut self, new_len: usize, value: T) {
|
|
let len = self.len();
|
|
|
|
if new_len > len {
|
|
self.extend(repeat(value).take(new_len - len));
|
|
} else {
|
|
self.truncate(new_len);
|
|
}
|
|
}
|
|
|
|
/// 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.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// let mut vec = vec![1];
|
|
/// vec.push_all(&[2, 3, 4]);
|
|
/// assert_eq!(vec, [1, 2, 3, 4]);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "collections",
|
|
reason = "likely to be replaced by a more optimized extend")]
|
|
pub fn push_all(&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 unsafe 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
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
impl<T> Vec<T> {
|
|
/// Reserves capacity for exactly `capacity` elements in the given vector.
|
|
///
|
|
/// If the capacity for `self` is already equal to or greater than the
|
|
/// requested capacity, then no action is taken.
|
|
fn grow_capacity(&mut self, capacity: usize) {
|
|
if mem::size_of::<T>() == 0 { return }
|
|
|
|
if capacity > self.cap {
|
|
let size = capacity.checked_mul(mem::size_of::<T>())
|
|
.expect("capacity overflow");
|
|
unsafe {
|
|
let ptr = alloc_or_realloc(*self.ptr, self.cap * mem::size_of::<T>(), size);
|
|
if ptr.is_null() { ::alloc::oom() }
|
|
self.ptr = Unique::new(ptr);
|
|
}
|
|
self.cap = capacity;
|
|
}
|
|
}
|
|
}
|
|
|
|
// FIXME: #13996: need a way to mark the return value as `noalias`
|
|
#[inline(never)]
|
|
unsafe fn alloc_or_realloc<T>(ptr: *mut T, old_size: usize, size: usize) -> *mut T {
|
|
if old_size == 0 {
|
|
allocate(size, mem::min_align_of::<T>()) as *mut T
|
|
} else {
|
|
reallocate(ptr as *mut u8, old_size, size, mem::min_align_of::<T>()) as *mut T
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn dealloc<T>(ptr: *mut T, len: usize) {
|
|
if mem::size_of::<T>() != 0 {
|
|
deallocate(ptr as *mut u8,
|
|
len * mem::size_of::<T>(),
|
|
mem::min_align_of::<T>())
|
|
}
|
|
}
|
|
|
|
#[doc(hidden)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> {
|
|
unsafe {
|
|
let mut v = Vec::with_capacity(n);
|
|
let mut ptr = v.as_mut_ptr();
|
|
|
|
// Write all elements except the last one
|
|
for i in 1..n {
|
|
ptr::write(ptr, Clone::clone(&elem));
|
|
ptr = ptr.offset(1);
|
|
v.set_len(i); // Increment the length in every step in case Clone::clone() panics
|
|
}
|
|
|
|
if n > 0 {
|
|
// We can write the last element directly without cloning needlessly
|
|
ptr::write(ptr, elem);
|
|
v.set_len(n);
|
|
}
|
|
|
|
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
|
|
if self.len() > other.len() {
|
|
self.truncate(other.len())
|
|
}
|
|
|
|
// reuse the contained values' allocations/resources.
|
|
for (place, thing) in self.iter_mut().zip(other.iter()) {
|
|
place.clone_from(thing)
|
|
}
|
|
|
|
// self.len <= other.len due to the truncate above, so the
|
|
// slice here is always in-bounds.
|
|
let slice = &other[self.len()..];
|
|
self.push_all(slice);
|
|
}
|
|
}
|
|
|
|
#[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
|
|
}
|
|
}
|
|
|
|
#[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
|
|
}
|
|
}
|
|
|
|
#[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.ptr;
|
|
assume(p != 0 as *mut T);
|
|
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.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>>(iterable: I) -> Vec<T> {
|
|
let mut iterator = iterable.into_iter();
|
|
let (lower, _) = iterator.size_hint();
|
|
let mut vector = Vec::with_capacity(lower);
|
|
|
|
// This function should be the moral equivalent of:
|
|
//
|
|
// for item in iterator {
|
|
// vector.push(item);
|
|
// }
|
|
//
|
|
// This equivalent crucially runs the iterator precisely once. Below we
|
|
// actually in theory run the iterator twice (one without bounds checks
|
|
// and one with). To achieve the "moral equivalent", we use the `if`
|
|
// statement below to break out early.
|
|
//
|
|
// If the first loop has terminated, then we have one of two conditions.
|
|
//
|
|
// 1. The underlying iterator returned `None`. In this case we are
|
|
// guaranteed that less than `vector.capacity()` elements have been
|
|
// returned, so we break out early.
|
|
// 2. The underlying iterator yielded `vector.capacity()` elements and
|
|
// has not yielded `None` yet. In this case we run the iterator to
|
|
// its end below.
|
|
for element in iterator.by_ref().take(vector.capacity()) {
|
|
let len = vector.len();
|
|
unsafe {
|
|
ptr::write(vector.get_unchecked_mut(len), element);
|
|
vector.set_len(len + 1);
|
|
}
|
|
}
|
|
|
|
if vector.len() == vector.capacity() {
|
|
for element in iterator {
|
|
vector.push(element);
|
|
}
|
|
}
|
|
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(self) -> IntoIter<T> {
|
|
unsafe {
|
|
let ptr = *self.ptr;
|
|
assume(!ptr.is_null());
|
|
let cap = self.cap;
|
|
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
|
|
};
|
|
mem::forget(self);
|
|
IntoIter { allocation: ptr, cap: cap, 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, iterable: I) {
|
|
let iterator = iterable.into_iter();
|
|
let (lower, _) = iterator.size_hint();
|
|
self.reserve(lower);
|
|
for element in iterator {
|
|
self.push(element)
|
|
}
|
|
}
|
|
}
|
|
|
|
__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> {
|
|
fn drop(&mut self) {
|
|
// This is (and should always remain) a no-op if the fields are
|
|
// zeroed (when moving out, because of #[unsafe_no_drop_flag]).
|
|
if self.cap != 0 && self.cap != mem::POST_DROP_USIZE {
|
|
unsafe {
|
|
for x in &*self {
|
|
ptr::read(x);
|
|
}
|
|
dealloc(*self.ptr, self.cap)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Default for Vec<T> {
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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 = "rust1", since = "1.0.0")]
|
|
impl<T> AsRef<[T]> for Vec<T> {
|
|
fn as_ref(&self) -> &[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 = "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))
|
|
}
|
|
}
|
|
|
|
impl<'a, T: 'a> IntoCow<'a, [T]> for Vec<T> where T: Clone {
|
|
fn into_cow(self) -> Cow<'a, [T]> {
|
|
Cow::Owned(self)
|
|
}
|
|
}
|
|
|
|
impl<'a, T> IntoCow<'a, [T]> for &'a [T] where T: Clone {
|
|
fn into_cow(self) -> Cow<'a, [T]> {
|
|
Cow::Borrowed(self)
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Iterators
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
/// An iterator that moves out of a vector.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct IntoIter<T> {
|
|
allocation: *mut T, // the block of memory allocated for the vector
|
|
cap: usize, // the capacity of the vector
|
|
ptr: *const T,
|
|
end: *const T
|
|
}
|
|
|
|
unsafe impl<T: Send> Send for IntoIter<T> { }
|
|
unsafe impl<T: Sync> Sync for IntoIter<T> { }
|
|
|
|
impl<T> IntoIter<T> {
|
|
#[inline]
|
|
/// Drops all items that have not yet been moved and returns the empty vector.
|
|
#[unstable(feature = "collections")]
|
|
pub fn into_inner(mut self) -> Vec<T> {
|
|
unsafe {
|
|
for _x in self.by_ref() { }
|
|
let IntoIter { allocation, cap, ptr: _ptr, end: _end } = self;
|
|
mem::forget(self);
|
|
Vec::from_raw_parts(allocation, 0, cap)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[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.size_hint().0
|
|
}
|
|
}
|
|
|
|
#[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(mem::transmute(self.end)))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> ExactSizeIterator for IntoIter<T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Drop for IntoIter<T> {
|
|
fn drop(&mut self) {
|
|
// destroy the remaining elements
|
|
if self.cap != 0 {
|
|
for _x in self.by_ref() {}
|
|
unsafe {
|
|
dealloc(self.allocation, self.cap);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A draining iterator for `Vec<T>`.
|
|
#[unstable(feature = "collections_drain", reason = "recently added")]
|
|
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::IterMut<'a, T>,
|
|
vec: *mut Vec<T>,
|
|
}
|
|
|
|
unsafe impl<'a, T: Sync> Sync for Drain<'a, T> {}
|
|
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> {}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Conversion from &[T] to &Vec<T>
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
/// Wrapper type providing a `&Vec<T>` reference via `Deref`.
|
|
#[unstable(feature = "collections")]
|
|
pub struct DerefVec<'a, T:'a> {
|
|
x: Vec<T>,
|
|
l: PhantomData<&'a T>,
|
|
}
|
|
|
|
#[unstable(feature = "collections")]
|
|
impl<'a, T> Deref for DerefVec<'a, T> {
|
|
type Target = Vec<T>;
|
|
|
|
fn deref<'b>(&'b self) -> &'b Vec<T> {
|
|
&self.x
|
|
}
|
|
}
|
|
|
|
// Prevent the inner `Vec<T>` from attempting to deallocate memory.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Drop for DerefVec<'a, T> {
|
|
fn drop(&mut self) {
|
|
self.x.len = 0;
|
|
self.x.cap = 0;
|
|
}
|
|
}
|
|
|
|
/// Converts a slice to a wrapper type providing a `&Vec<T>` reference.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::vec::as_vec;
|
|
///
|
|
/// // Let's pretend we have a function that requires `&Vec<i32>`
|
|
/// fn vec_consumer(s: &Vec<i32>) {
|
|
/// assert_eq!(s, &[1, 2, 3]);
|
|
/// }
|
|
///
|
|
/// // Provide a `&Vec<i32>` from a `&[i32]` without allocating
|
|
/// let values = [1, 2, 3];
|
|
/// vec_consumer(&as_vec(&values));
|
|
/// ```
|
|
#[unstable(feature = "collections")]
|
|
pub fn as_vec<'a, T>(x: &'a [T]) -> DerefVec<'a, T> {
|
|
unsafe {
|
|
DerefVec {
|
|
x: Vec::from_raw_parts(x.as_ptr() as *mut T, x.len(), x.len()),
|
|
l: PhantomData,
|
|
}
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
// Partial vec, used for map_in_place
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
/// An owned, partially type-converted vector of elements with non-zero size.
|
|
///
|
|
/// `T` and `U` must have the same, non-zero size. They must also have the same
|
|
/// alignment.
|
|
///
|
|
/// When the destructor of this struct runs, all `U`s from `start_u` (incl.) to
|
|
/// `end_u` (excl.) and all `T`s from `start_t` (incl.) to `end_t` (excl.) are
|
|
/// destructed. Additionally the underlying storage of `vec` will be freed.
|
|
struct PartialVecNonZeroSized<T,U> {
|
|
vec: Vec<T>,
|
|
|
|
start_u: *mut U,
|
|
end_u: *mut U,
|
|
start_t: *mut T,
|
|
end_t: *mut T,
|
|
|
|
_marker: PhantomData<U>,
|
|
}
|
|
|
|
/// An owned, partially type-converted vector of zero-sized elements.
|
|
///
|
|
/// When the destructor of this struct runs, all `num_t` `T`s and `num_u` `U`s
|
|
/// are destructed.
|
|
struct PartialVecZeroSized<T,U> {
|
|
num_t: usize,
|
|
num_u: usize,
|
|
marker: PhantomData<::core::cell::Cell<(T,U)>>,
|
|
}
|
|
|
|
impl<T,U> Drop for PartialVecNonZeroSized<T,U> {
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
// `vec` hasn't been modified until now. As it has a length
|
|
// currently, this would run destructors of `T`s which might not be
|
|
// there. So at first, set `vec`s length to `0`. This must be done
|
|
// at first to remain memory-safe as the destructors of `U` or `T`
|
|
// might cause unwinding where `vec`s destructor would be executed.
|
|
self.vec.set_len(0);
|
|
|
|
// We have instances of `U`s and `T`s in `vec`. Destruct them.
|
|
while self.start_u != self.end_u {
|
|
let _ = ptr::read(self.start_u); // Run a `U` destructor.
|
|
self.start_u = self.start_u.offset(1);
|
|
}
|
|
while self.start_t != self.end_t {
|
|
let _ = ptr::read(self.start_t); // Run a `T` destructor.
|
|
self.start_t = self.start_t.offset(1);
|
|
}
|
|
// After this destructor ran, the destructor of `vec` will run,
|
|
// deallocating the underlying memory.
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T,U> Drop for PartialVecZeroSized<T,U> {
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
// Destruct the instances of `T` and `U` this struct owns.
|
|
while self.num_t != 0 {
|
|
let _: T = mem::uninitialized(); // Run a `T` destructor.
|
|
self.num_t -= 1;
|
|
}
|
|
while self.num_u != 0 {
|
|
let _: U = mem::uninitialized(); // Run a `U` destructor.
|
|
self.num_u -= 1;
|
|
}
|
|
}
|
|
}
|
|
}
|