// option. This file may not be copied, modified, or distributed
// except according to those terms.
-//! A growable list type with heap-allocated contents, written `Vec<T>` but
-//! pronounced 'vector.'
+//! A contiguous growable array type with heap-allocated contents, written
+//! `Vec<T>` but pronounced 'vector.'
//!
-//! Vectors have `O(1)` indexing, push (to the end) and pop (from the end).
+//! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and
+//! `O(1)` pop (from the end).
//!
//! # Examples
//!
//! let v = vec![0; 10]; // ten zeroes
//! ```
//!
-//! You can `push` values onto the end of a vector (which will grow the vector as needed):
+//! You can `push` values onto the end of a vector (which will grow the vector
+//! as needed):
//!
//! ```
//! let mut v = vec![1, 2];
#![stable(feature = "rust1", since = "1.0.0")]
-use core::prelude::*;
-
use alloc::boxed::Box;
-use alloc::heap::{EMPTY, allocate, reallocate, deallocate};
-use core::cmp::max;
+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::assume;
-use core::iter::{repeat, FromIterator};
-use core::marker::PhantomData;
+use core::intrinsics::{arith_offset, assume};
+use core::iter::{FromIterator, FusedIterator};
use core::mem;
-use core::ops::{Index, IndexMut, Deref};
+use core::ops::{Index, IndexMut};
use core::ops;
use core::ptr;
-use core::ptr::Unique;
+use core::ptr::Shared;
use core::slice;
-use core::isize;
-use core::usize;
-
-use borrow::{Cow, IntoCow};
+use super::SpecExtend;
use super::range::RangeArgument;
-// FIXME- fix places which assume the max vector allowed has memory usize::MAX.
-static MAX_MEMORY_SIZE: usize = isize::MAX as usize;
-
-/// A growable list type, written `Vec<T>` but pronounced 'vector.'
+/// A contiguous growable array type, written `Vec<T>` but pronounced 'vector.'
///
/// # Examples
///
/// ```
-/// # #![feature(collections)]
/// let mut vec = Vec::new();
/// vec.push(1);
/// vec.push(2);
/// vec[0] = 7;
/// assert_eq!(vec[0], 7);
///
-/// vec.push_all(&[1, 2, 3]);
+/// vec.extend([1, 2, 3].iter().cloned());
///
-/// for x in vec.iter() {
+/// for x in &vec {
/// println!("{}", x);
/// }
/// assert_eq!(vec, [7, 1, 2, 3]);
/// 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:
///
/// ```
/// }
/// ```
///
+/// # 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
/// 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.
-#[unsafe_no_drop_flag]
+///
+/// # 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).
+///
+#[cfg_attr(stage0, unsafe_no_drop_flag)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Vec<T> {
- ptr: Unique<T>,
+ buf: RawVec<T>,
len: usize,
- cap: usize,
}
-unsafe impl<T: Send> Send for Vec<T> { }
-unsafe impl<T: Sync> Sync for Vec<T> { }
-
////////////////////////////////////////////////////////////////////////////////
// Inherent methods
////////////////////////////////////////////////////////////////////////////////
/// # Examples
///
/// ```
+ /// # #![allow(unused_mut)]
/// let mut vec: Vec<i32> = Vec::new();
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn new() -> Vec<T> {
- // We want ptr to never be NULL so instead we set it to some arbitrary
- // non-null value which is fine since we never call deallocate on the ptr
- // if cap is 0. The reason for this is because the pointer of a slice
- // being NULL would break the null pointer optimization for enums.
- unsafe { Vec::from_raw_parts(EMPTY as *mut T, 0, 0) }
+ 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.
+ /// 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'.)
+ /// 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
///
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn with_capacity(capacity: usize) -> Vec<T> {
- if mem::size_of::<T>() == 0 {
- unsafe { Vec::from_raw_parts(EMPTY as *mut T, 0, usize::MAX) }
- } else if capacity == 0 {
- Vec::new()
- } else {
- let size = capacity.checked_mul(mem::size_of::<T>())
- .expect("capacity overflow");
- let ptr = unsafe { allocate(size, mem::min_align_of::<T>()) };
- if ptr.is_null() { ::alloc::oom() }
- unsafe { Vec::from_raw_parts(ptr as *mut T, 0, capacity) }
+ Vec {
+ buf: RawVec::with_capacity(capacity),
+ len: 0,
}
}
/// Creates a `Vec<T>` directly from the raw components of another vector.
///
- /// This is highly unsafe, due to the number of invariants that aren't checked.
+ /// # 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
///
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
- pub unsafe fn from_raw_parts(ptr: *mut T, length: usize,
- capacity: usize) -> Vec<T> {
+ pub unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Vec<T> {
Vec {
- ptr: Unique::new(ptr),
+ buf: RawVec::from_raw_parts(ptr, capacity),
len: length,
- cap: capacity,
}
}
- /// Creates a vector by copying the elements from a raw pointer.
- ///
- /// This function will copy `elts` contiguous elements starting at `ptr`
- /// into a new allocation owned by the returned `Vec<T>`. The elements of
- /// the buffer are copied into the vector without cloning, as if
- /// `ptr::read()` were called on them.
- #[inline]
- #[unstable(feature = "collections",
- reason = "may be better expressed via composition")]
- pub unsafe fn from_raw_buf(ptr: *const T, elts: usize) -> Vec<T> {
- let mut dst = Vec::with_capacity(elts);
- dst.set_len(elts);
- ptr::copy_nonoverlapping(ptr, dst.as_mut_ptr(), elts);
- dst
- }
-
/// Returns the number of elements the vector can hold without
/// reallocating.
///
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn capacity(&self) -> usize {
- self.cap
+ self.buf.cap()
}
/// Reserves capacity for at least `additional` more elements to be inserted
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn reserve(&mut self, additional: usize) {
- if self.cap - self.len < additional {
- const ERR_MSG: &'static str = "Vec::reserve: `isize` overflow";
-
- let new_min_cap = self.len.checked_add(additional).expect(ERR_MSG);
- if new_min_cap > MAX_MEMORY_SIZE { panic!(ERR_MSG) }
- self.grow_capacity(match new_min_cap.checked_next_power_of_two() {
- Some(x) if x > MAX_MEMORY_SIZE => MAX_MEMORY_SIZE,
- None => MAX_MEMORY_SIZE,
- Some(x) => x,
- });
- }
+ self.buf.reserve(self.len, additional);
}
/// Reserves the minimum capacity for exactly `additional` more elements to
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn reserve_exact(&mut self, additional: usize) {
- if self.cap - self.len < additional {
- match self.len.checked_add(additional) {
- None => panic!("Vec::reserve: `usize` overflow"),
- Some(new_cap) => self.grow_capacity(new_cap)
- }
- }
+ self.buf.reserve_exact(self.len, additional);
}
/// Shrinks the capacity of the vector as much as possible.
/// # Examples
///
/// ```
- /// # #![feature(collections)]
/// let mut vec = Vec::with_capacity(10);
- /// vec.push_all(&[1, 2, 3]);
+ /// 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) {
- if mem::size_of::<T>() == 0 { return }
-
- if self.len == 0 {
- if self.cap != 0 {
- unsafe {
- dealloc(*self.ptr, self.cap)
- }
- self.cap = 0;
- }
- } else if self.cap != self.len {
- unsafe {
- // Overflow check is unnecessary as the vector is already at
- // least this large.
- let ptr = reallocate(*self.ptr as *mut u8,
- self.cap * mem::size_of::<T>(),
- self.len * mem::size_of::<T>(),
- mem::min_align_of::<T>()) as *mut T;
- if ptr.is_null() { ::alloc::oom() }
- self.ptr = Unique::new(ptr);
- }
- self.cap = self.len;
- }
+ 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()`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let v = vec![1, 2, 3];
+ ///
+ /// let slice = v.into_boxed_slice();
+ /// ```
+ ///
+ /// Any excess capacity is removed:
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3].iter().cloned());
+ ///
+ /// assert_eq!(vec.capacity(), 10);
+ /// let slice = vec.into_boxed_slice();
+ /// assert_eq!(slice.into_vec().capacity(), 3);
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn into_boxed_slice(mut self) -> Box<[T]> {
- self.shrink_to_fit();
unsafe {
- let xs: Box<[T]> = Box::from_raw(&mut *self);
+ self.shrink_to_fit();
+ let buf = ptr::read(&self.buf);
mem::forget(self);
- xs
+ buf.into_box()
}
}
- /// Shorten a vector, dropping excess elements.
+ /// 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:
+ ///
/// ```
- /// # #![feature(collections)]
- /// let mut vec = vec![1, 2, 3, 4];
+ /// 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 read(), so a panic on Drop doesn't
- // re-drop the just-failed value.
+ // decrement len before the drop_in_place(), so a panic on Drop
+ // doesn't re-drop the just-failed value.
self.len -= 1;
- ptr::read(self.get_unchecked(self.len));
+ 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]
- #[unstable(feature = "convert",
- reason = "waiting on RFC revision")]
+ #[stable(feature = "vec_as_slice", since = "1.7.0")]
pub fn as_slice(&self) -> &[T] {
self
}
- /// Deprecated: use `&mut s[..]` instead.
+ /// 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]
- #[unstable(feature = "convert",
- reason = "waiting on RFC revision")]
+ #[stable(feature = "vec_as_slice", since = "1.7.0")]
pub fn as_mut_slice(&mut self) -> &mut [T] {
- &mut self[..]
+ self
}
/// Sets the length of a vector.
/// # Examples
///
/// ```
- /// let mut v = vec![1, 2, 3, 4];
+ /// 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 {
- /// v.set_len(1);
+ /// 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]
}
/// Inserts an element at position `index` within the vector, shifting all
- /// elements after position `i` one position to the right.
+ /// elements after it to the right.
///
/// # Panics
///
pub fn insert(&mut self, index: usize, element: T) {
let len = self.len();
assert!(index <= len);
+
// space for the new element
- self.reserve(1);
+ if len == self.buf.cap() {
+ self.buf.double();
+ }
- unsafe { // infallible
+ 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);
+ 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);
+ ptr::write(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.
+ /// shifting all elements after it to the left.
///
/// # Panics
///
/// # Examples
///
/// ```
- /// # #![feature(collections)]
/// let mut v = vec![1, 2, 3];
/// assert_eq!(v.remove(1), 2);
/// assert_eq!(v, [1, 3]);
pub fn remove(&mut self, index: usize) -> T {
let len = self.len();
assert!(index < len);
- unsafe { // infallible
+ unsafe {
+ // infallible
let ret;
{
// the place we are taking from.
ret = ptr::read(ptr);
// Shift everything down to fill in that spot.
- ptr::copy(&*ptr.offset(1), ptr, len - index - 1);
+ ptr::copy(ptr.offset(1), ptr, len - index - 1);
}
self.set_len(len - 1);
ret
/// 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 {
+ pub fn retain<F>(&mut self, mut f: F)
+ where F: FnMut(&T) -> bool
+ {
let len = self.len();
let mut del = 0;
{
if !f(&v[i]) {
del += 1;
} else if del > 0 {
- v.swap(i-del, i);
+ v.swap(i - del, i);
}
}
}
/// # Examples
///
/// ```
- /// let mut vec = vec!(1, 2);
+ /// 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
+ // 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();
}
-
- if self.len == self.cap {
- resize(self);
- }
-
unsafe {
- let end = (*self.ptr).offset(self.len as isize);
- ptr::write(&mut *end, value);
+ 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.
+ /// Removes the last element from a vector and returns it, or `None` if it
+ /// is empty.
///
/// # Examples
///
/// # Examples
///
/// ```
- /// # #![feature(collections)]
/// let mut vec = vec![1, 2, 3];
/// let mut vec2 = vec![4, 5, 6];
/// vec.append(&mut vec2);
/// assert_eq!(vec2, []);
/// ```
#[inline]
- #[unstable(feature = "collections",
- reason = "new API, waiting for dust to settle")]
+ #[stable(feature = "append", since = "1.4.0")]
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());
+ ptr::copy_nonoverlapping(other.as_ptr(), self.get_unchecked_mut(len), other.len());
}
self.len += other.len();
- unsafe { other.set_len(0); }
+ 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.
+ /// and yields the removed items.
+ ///
+ /// Note 1: 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,
+ /// Note 2: It is unspecified how many elements are removed from the vector,
/// if the `Drain` value is leaked.
///
/// # Panics
/// # Examples
///
/// ```
- /// # #![feature(collections_drain, collections_range)]
- ///
- /// // Draining using `..` clears the whole vector.
/// let mut v = vec![1, 2, 3];
- /// let u: Vec<_> = v.drain(..).collect();
+ /// 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, &[]);
- /// 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> {
+ #[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
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);
+ 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 _,
+ iter: range_slice.iter(),
+ vec: Shared::new(self as *mut _),
}
}
}
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
- pub fn len(&self) -> usize { self.len }
+ pub fn len(&self) -> usize {
+ self.len
+ }
/// Returns `true` if the vector contains no elements.
///
/// 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, core)]
- /// 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
- }
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
}
/// Splits the collection into two at the given index.
/// # 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")]
+ #[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");
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());
+ 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.
+ /// 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
///
/// ```
- /// # #![feature(collections)]
/// let mut vec = vec!["hello"];
/// vec.resize(3, "world");
/// assert_eq!(vec, ["hello", "world", "world"]);
/// vec.resize(2, 0);
/// assert_eq!(vec, [1, 2]);
/// ```
- #[unstable(feature = "collections",
- reason = "matches collection reform specification; waiting for dust to settle")]
+ #[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(repeat(value).take(new_len - len));
+ self.extend_with_element(new_len - len, value);
} else {
self.truncate(new_len);
}
}
- /// Appends all elements in a slice to the `Vec`.
+ /// Extend the vector by `n` additional clones of `value`.
+ fn extend_with_element(&mut self, n: usize, value: T) {
+ self.reserve(n);
+
+ unsafe {
+ let mut ptr = self.as_mut_ptr().offset(self.len() as isize);
+ // Use SetLenOnDrop to work around bug where compiler
+ // may not realize the store through `ptr` trough self.set_len()
+ // don't alias.
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+ // Write all elements except the last one
+ for _ in 1..n {
+ ptr::write(ptr, value.clone());
+ ptr = ptr.offset(1);
+ // Increment the length in every step in case clone() panics
+ local_len.increment_len(1);
+ }
+
+ if n > 0 {
+ // We can write the last element directly without cloning needlessly
+ ptr::write(ptr, value);
+ local_len.increment_len(1);
+ }
+
+ // len set by scope guard
+ }
+ }
+
+ /// 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
///
/// ```
- /// # #![feature(collections)]
/// let mut vec = vec![1];
- /// vec.push_all(&[2, 3, 4]);
+ /// vec.extend_from_slice(&[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]) {
+ #[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() {
+ // 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 {
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);
+ let ptr = self.get_unchecked_mut(len) as *mut T;
+ // Use SetLenOnDrop to work around bug where compiler
+ // may not realize the store through `ptr` trough self.set_len()
+ // don't alias.
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+ for i in 0..other.len() {
+ ptr::write(ptr.offset(i as isize), other.get_unchecked(i).clone());
+ local_len.increment_len(1);
}
+
+ // len set by scope guard
}
}
}
+// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
+//
+// The idea is: The length field in SetLenOnDrop is a local variable
+// that the optimizer will see does not alias with any stores through the Vec's data
+// pointer. This is a workaround for alias analysis issue #32155
+struct SetLenOnDrop<'a> {
+ len: &'a mut usize,
+ local_len: usize,
+}
+
+impl<'a> SetLenOnDrop<'a> {
+ #[inline]
+ fn new(len: &'a mut usize) -> Self {
+ SetLenOnDrop { local_len: *len, len: len }
+ }
+
+ #[inline]
+ fn increment_len(&mut self, increment: usize) {
+ self.local_len += increment;
+ }
+}
+
+impl<'a> Drop for SetLenOnDrop<'a> {
+ #[inline]
+ fn drop(&mut self) {
+ *self.len = self.local_len;
+ }
+}
+
impl<T: PartialEq> Vec<T> {
/// Removes consecutive repeated elements in the vector.
///
// Duplicate, advance r. End of vec. Truncate to w.
let ln = self.len();
- if ln < 1 { return; }
+ if ln <= 1 {
+ return;
+ }
- // Avoid bounds checks by using unsafe pointers.
+ // Avoid bounds checks by using raw pointers.
let p = self.as_mut_ptr();
let mut r: usize = 1;
let mut w: usize = 1;
// 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
- }
+ let mut v = Vec::with_capacity(n);
+ v.extend_with_element(n, elem);
+ v
}
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
#[stable(feature = "rust1", since = "1.0.0")]
-impl<T:Clone> Clone for Vec<T> {
+impl<T: Clone> Clone for Vec<T> {
#[cfg(not(test))]
- fn clone(&self) -> Vec<T> { <[T]>::to_vec(&**self) }
+ 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
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())
- }
+ self.truncate(other.len());
+ let len = self.len();
// reuse the contained values' allocations/resources.
- for (place, thing) in self.iter_mut().zip(other.iter()) {
- place.clone_from(thing)
- }
+ self.clone_from_slice(&other[..len]);
// 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);
+ self.extend_from_slice(&other[len..]);
}
}
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> {
fn deref(&self) -> &[T] {
unsafe {
- let p = *self.ptr;
- assume(p != 0 as *mut T);
+ let p = self.buf.ptr();
+ assume(!p.is_null());
slice::from_raw_parts(p, self.len)
}
}
impl<T> ops::DerefMut for Vec<T> {
fn deref_mut(&mut self) -> &mut [T] {
unsafe {
- let ptr = *self.ptr;
+ 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>>(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);
+ 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
}
}
/// }
/// ```
#[inline]
- fn into_iter(self) -> IntoIter<T> {
+ fn into_iter(mut self) -> IntoIter<T> {
unsafe {
- let ptr = *self.ptr;
- assume(!ptr.is_null());
- let cap = self.cap;
- let begin = ptr as *const T;
+ let begin = self.as_mut_ptr();
+ assume(!begin.is_null());
let end = if mem::size_of::<T>() == 0 {
- (ptr as usize + self.len()) as *const T
+ arith_offset(begin as *const i8, self.len() as isize) as *const T
} else {
- ptr.offset(self.len() as isize) as *const T
+ begin.offset(self.len() as isize) as *const T
};
+ let cap = self.buf.cap();
mem::forget(self);
- IntoIter { allocation: ptr, cap: cap, ptr: begin, end: end }
+ IntoIter {
+ buf: Shared::new(begin),
+ cap: cap,
+ ptr: begin,
+ end: end,
+ }
}
}
}
#[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)
+ 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[..] }
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T> Drop for Vec<T> {
+ #[unsafe_destructor_blind_to_params]
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)
- }
+ 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> {
- #[stable(feature = "rust1", since = "1.0.0")]
+ /// Creates an empty `Vec<T>`.
fn default() -> Vec<T> {
Vec::new()
}
}
}
+#[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] {
}
}
+#[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))]
// 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))
+#[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)
}
}
-impl<'a, T: 'a> IntoCow<'a, [T]> for Vec<T> where T: Clone {
- fn into_cow(self) -> Cow<'a, [T]> {
- Cow::Owned(self)
+#[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)
}
}
-impl<'a, T> IntoCow<'a, [T]> for &'a [T] where T: Clone {
- fn into_cow(self) -> Cow<'a, [T]> {
- Cow::Borrowed(self)
+#[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))
}
}
////////////////////////////////////////////////////////////////////////////////
/// 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> {
- allocation: *mut T, // the block of memory allocated for the vector
- cap: usize, // the capacity of the vector
+ buf: Shared<T>,
+ cap: usize,
ptr: *const T,
- end: *const T
+ end: *const T,
}
-unsafe impl<T: Send> Send for IntoIter<T> { }
-unsafe impl<T: Sync> Sync for IntoIter<T> { }
+#[stable(feature = "vec_intoiter_debug", since = "")]
+impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.debug_tuple("IntoIter")
+ .field(&self.as_slice())
+ .finish()
+ }
+}
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> {
+ /// Returns the remaining items of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// # #![feature(vec_into_iter_as_slice)]
+ /// let vec = vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// let _ = into_iter.next().unwrap();
+ /// assert_eq!(into_iter.as_slice(), &['b', 'c']);
+ /// ```
+ #[unstable(feature = "vec_into_iter_as_slice", issue = "35601")]
+ pub fn as_slice(&self) -> &[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)
+ slice::from_raw_parts(self.ptr, self.len())
+ }
+ }
+
+ /// Returns the remaining items of this iterator as a mutable slice.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// # #![feature(vec_into_iter_as_slice)]
+ /// let vec = vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// into_iter.as_mut_slice()[2] = 'z';
+ /// assert_eq!(into_iter.next().unwrap(), 'a');
+ /// assert_eq!(into_iter.next().unwrap(), 'b');
+ /// assert_eq!(into_iter.next().unwrap(), 'z');
+ /// ```
+ #[unstable(feature = "vec_into_iter_as_slice", issue = "35601")]
+ pub fn as_mut_slice(&self) -> &mut [T] {
+ unsafe {
+ slice::from_raw_parts_mut(self.ptr as *mut T, self.len())
}
}
}
+#[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 {
+ if self.ptr as *const _ == 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 = mem::transmute(self.ptr as usize + 1);
+ self.ptr = arith_offset(self.ptr as *const i8, 1) as *mut T;
// Use a non-null pointer value
Some(ptr::read(EMPTY as *mut T))
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});
+ let exact = diff /
+ (if size == 0 {
+ 1
+ } else {
+ size
+ });
(exact, Some(exact))
}
#[inline]
fn count(self) -> usize {
- self.size_hint().0
+ self.len()
}
}
} else {
if mem::size_of::<T>() == 0 {
// See above for why 'ptr.offset' isn't used
- self.end = mem::transmute(self.end as usize - 1);
+ self.end = arith_offset(self.end as *const i8, -1) as *mut 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)))
+ Some(ptr::read(self.end))
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T> ExactSizeIterator for IntoIter<T> {}
+#[unstable(feature = "fused", issue = "35602")]
+impl<T> FusedIterator 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> {
+ self.as_slice().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
- if self.cap != 0 {
- for _x in self.by_ref() {}
- unsafe {
- dealloc(self.allocation, self.cap);
- }
- }
+ for _x in self.by_ref() {}
+
+ // RawVec handles deallocation
+ let _ = unsafe { RawVec::from_raw_parts(*self.buf, self.cap) };
}
}
/// A draining iterator for `Vec<T>`.
-#[unstable(feature = "collections_drain", reason = "recently added")]
+///
+/// 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::IterMut<'a, T>,
- vec: *mut Vec<T>,
+ 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")]
#[inline]
fn next(&mut self) -> Option<T> {
- self.iter.next().map(|elt|
- unsafe {
- ptr::read(elt as *const _)
- }
- )
+ self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) })
}
fn size_hint(&self) -> (usize, Option<usize>) {
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 _)
- }
- )
+ self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
}
}
impl<'a, T> Drop for Drain<'a, T> {
fn drop(&mut self) {
// exhaust self first
- while let Some(_) = self.next() { }
+ while let Some(_) = self.next() {}
if self.tail_len > 0 {
unsafe {
- let source_vec = &mut *self.vec;
+ let source_vec = &mut **self.vec;
// memmove back untouched tail, update to new length
let start = source_vec.len();
let tail = self.tail_start;
#[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;
- }
- }
- }
-}
+#[unstable(feature = "fused", issue = "35602")]
+impl<'a, T> FusedIterator for Drain<'a, T> {}
projects / rustc.git / blobdiff