use core::ops::{Index, IndexMut};
use core::ops;
use core::ptr;
+use core::ptr::Shared;
use core::slice;
use super::SpecExtend;
///
/// * `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 the length that less than or equal to `capacity`.
+ /// * `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
///
/// ```
/// 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]> {
unsafe {
}
}
- /// Shorten a vector to be `len` elements long, 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:
+ ///
/// ```
/// 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 {
/// Extracts a slice containing the entire vector.
///
/// Equivalent to `&s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{self, Write};
+ /// let buffer = vec![1, 2, 3, 5, 8];
+ /// io::sink().write(buffer.as_slice()).unwrap();
+ /// ```
#[inline]
#[stable(feature = "vec_as_slice", since = "1.7.0")]
pub fn as_slice(&self) -> &[T] {
/// Extracts a mutable slice of the entire vector.
///
/// Equivalent to `&mut s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{self, Read};
+ /// let mut buffer = vec![0; 3];
+ /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();
+ /// ```
#[inline]
#[stable(feature = "vec_as_slice", since = "1.7.0")]
pub fn as_mut_slice(&mut self) -> &mut [T] {
- &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]
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]
fn into_iter(mut self) -> IntoIter<T> {
unsafe {
- let ptr = self.as_mut_ptr();
- assume(!ptr.is_null());
- let begin = ptr as *const T;
+ let begin = self.as_mut_ptr();
+ assume(!begin.is_null());
let end = if mem::size_of::<T>() == 0 {
- arith_offset(ptr as *const i8, self.len() as isize) 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 buf = ptr::read(&self.buf);
+ let cap = self.buf.cap();
mem::forget(self);
IntoIter {
- _buf: buf,
+ buf: Shared::new(begin),
+ cap: cap,
ptr: begin,
end: end,
}
////////////////////////////////////////////////////////////////////////////////
/// An iterator that moves out of a vector.
+///
+/// This `struct` is created by the `into_iter` method on [`Vec`][`Vec`] (provided
+/// by the [`IntoIterator`] trait).
+///
+/// [`Vec`]: struct.Vec.html
+/// [`IntoIterator`]: ../../std/iter/trait.IntoIterator.html
#[stable(feature = "rust1", since = "1.0.0")]
pub struct IntoIter<T> {
- _buf: RawVec<T>,
+ buf: Shared<T>,
+ cap: usize,
ptr: *const T,
end: *const T,
}
+impl<T> IntoIter<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 {
+ 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")]
#[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 = arith_offset(self.ptr as *const i8, 1) as *const T;
+ 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))
} 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;
+ 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))
#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
impl<T: Clone> Clone for IntoIter<T> {
fn clone(&self) -> IntoIter<T> {
- unsafe {
- slice::from_raw_parts(self.ptr, self.len()).to_owned().into_iter()
- }
+ self.as_slice().to_owned().into_iter()
}
}
#[unsafe_destructor_blind_to_params]
fn drop(&mut self) {
// destroy the remaining elements
- for _x in self {}
+ 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>`.
+///
+/// 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
/// 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")]
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;
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