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rust/src/libcollections/vec.rs
Steven Fackler e2605b42c7 Rename #[should_fail] to #[should_panic]
2015-03-09 10:14:21 -07:00

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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A growable list 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).
//!
//! # Examples
//!
//! Explicitly creating a `Vec<T>` with `new()`:
//!
//! ```
//! let xs: Vec<i32> = Vec::new();
//! ```
//!
//! Using the `vec!` macro:
//!
//! ```
//! let ys: Vec<i32> = vec![];
//!
//! let zs = vec![1i32, 2, 3, 4, 5];
//! ```
//!
//! Push:
//!
//! ```
//! let mut xs = vec![1i32, 2];
//!
//! xs.push(3);
//! ```
//!
//! And pop:
//!
//! ```
//! let mut xs = vec![1i32, 2];
//!
//! let two = xs.pop();
//! ```
#![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 core::cmp::{Ordering};
use core::default::Default;
use core::fmt;
use core::hash::{self, Hash};
use core::intrinsics::assume;
use core::iter::{repeat, FromIterator, IntoIterator};
use core::marker::PhantomData;
use core::mem;
use core::num::{Int, UnsignedInt};
use core::ops::{Index, IndexMut, Deref, Add};
use core::ops;
use core::ptr;
use core::ptr::Unique;
use core::raw::Slice as RawSlice;
use core::slice;
use core::usize;
use borrow::{Cow, IntoCow};
/// A growable list type, written `Vec<T>` but pronounced 'vector.'
///
/// # Examples
///
/// ```
/// let mut vec = Vec::new();
/// vec.push(1);
/// vec.push(2);
///
/// assert_eq!(vec.len(), 2);
/// assert_eq!(vec[0], 1);
///
/// assert_eq!(vec.pop(), Some(2));
/// assert_eq!(vec.len(), 1);
///
/// vec[0] = 7;
/// assert_eq!(vec[0], 7);
///
/// vec.push_all(&[1, 2, 3]);
///
/// for x in vec.iter() {
/// println!("{}", x);
/// }
/// assert_eq!(vec, [7, 1, 2, 3]);
/// ```
///
/// The `vec!` macro is provided to make initialization more convenient:
///
/// ```
/// let mut vec = vec![1, 2, 3];
/// vec.push(4);
/// assert_eq!(vec, [1, 2, 3, 4]);
/// ```
///
/// Use a `Vec<T>` as an efficient stack:
///
/// ```
/// let mut stack = Vec::new();
///
/// stack.push(1);
/// stack.push(2);
/// stack.push(3);
///
/// loop {
/// let top = match stack.pop() {
/// None => break, // empty
/// Some(x) => x,
/// };
/// // Prints 3, 2, 1
/// println!("{}", top);
/// }
/// ```
///
/// # Capacity and reallocation
///
/// The capacity of a vector is the amount of space allocated for any future elements that will be
/// added onto the vector. This is not to be confused with the *length* of a vector, which
/// specifies the number of actual elements within the vector. If a vector's length exceeds its
/// capacity, its capacity will automatically be increased, but its elements will have to be
/// reallocated.
///
/// For example, a vector with capacity 10 and length 0 would be an empty vector with space for 10
/// more elements. Pushing 10 or fewer elements onto the vector will not change its capacity or
/// cause reallocation to occur. However, if the vector's length is increased to 11, it will have
/// to reallocate, which can be slow. For this reason, it is recommended to use
/// `Vec::with_capacity` whenever possible to specify how big the vector is expected to get.
#[unsafe_no_drop_flag]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Vec<T> {
ptr: Unique<T>,
len: usize,
cap: usize,
}
unsafe impl<T: Send> Send for Vec<T> { }
unsafe impl<T: Sync> Sync for Vec<T> { }
////////////////////////////////////////////////////////////////////////////////
// Inherent methods
////////////////////////////////////////////////////////////////////////////////
impl<T> Vec<T> {
/// Constructs a new, empty `Vec<T>`.
///
/// The vector will not allocate until elements are pushed onto it.
///
/// # Examples
///
/// ```
/// 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) }
}
/// Constructs a new, empty `Vec<T>` with the specified capacity.
///
/// The vector will be able to hold exactly `capacity` elements without reallocating. If
/// `capacity` is 0, the vector will not allocate.
///
/// It is important to note that this function does not specify the *length* of the returned
/// vector, but only the *capacity*. (For an explanation of the difference between length and
/// capacity, see the main `Vec<T>` docs above, 'Capacity and reallocation'.)
///
/// # Examples
///
/// ```
/// let mut vec: Vec<_> = Vec::with_capacity(10);
///
/// // The vector contains no items, even though it has capacity for more
/// assert_eq!(vec.len(), 0);
///
/// // These are all done without reallocating...
/// for i in 0..10 {
/// vec.push(i);
/// }
///
/// // ...but this may make the vector reallocate
/// vec.push(11);
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn with_capacity(capacity: usize) -> Vec<T> {
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) }
}
}
/// 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.
///
/// # Examples
///
/// ```
/// use std::ptr;
/// use std::mem;
///
/// fn main() {
/// let mut v = vec![1, 2, 3];
///
/// // Pull out the various important pieces of information about `v`
/// let p = v.as_mut_ptr();
/// let len = v.len();
/// let cap = v.capacity();
///
/// unsafe {
/// // Cast `v` into the void: no destructor run, so we are in
/// // complete control of the allocation to which `p` points.
/// mem::forget(v);
///
/// // Overwrite memory with 4, 5, 6
/// for i in 0..len as isize {
/// ptr::write(p.offset(i), 4 + i);
/// }
///
/// // Put everything back together into a Vec
/// let rebuilt = Vec::from_raw_parts(p, len, cap);
/// assert_eq!(rebuilt, [4, 5, 6]);
/// }
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub unsafe fn from_raw_parts(ptr: *mut T, length: usize,
capacity: usize) -> Vec<T> {
Vec {
ptr: Unique::new(ptr),
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(dst.as_mut_ptr(), ptr, elts);
dst
}
/// Returns the number of elements the vector can hold without
/// reallocating.
///
/// # Examples
///
/// ```
/// let vec: Vec<i32> = Vec::with_capacity(10);
/// assert_eq!(vec.capacity(), 10);
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn capacity(&self) -> usize {
self.cap
}
/// Reserves capacity for at least `additional` more elements to be inserted in the given
/// `Vec<T>`. The collection may reserve more space to avoid frequent reallocations.
///
/// # Panics
///
/// Panics if the new capacity overflows `usize`.
///
/// # Examples
///
/// ```
/// let mut vec = vec![1];
/// vec.reserve(10);
/// assert!(vec.capacity() >= 11);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn reserve(&mut self, additional: usize) {
if self.cap - self.len < additional {
let err_msg = "Vec::reserve: `usize` overflow";
let new_cap = self.len.checked_add(additional).expect(err_msg)
.checked_next_power_of_two().expect(err_msg);
self.grow_capacity(new_cap);
}
}
/// Reserves the minimum capacity for exactly `additional` more elements to
/// be inserted in the given `Vec<T>`. Does nothing if the capacity is already
/// sufficient.
///
/// Note that the allocator may give the collection more space than it
/// requests. Therefore capacity can not be relied upon to be precisely
/// minimal. Prefer `reserve` if future insertions are expected.
///
/// # Panics
///
/// Panics if the new capacity overflows `usize`.
///
/// # Examples
///
/// ```
/// let mut vec = vec![1];
/// vec.reserve_exact(10);
/// assert!(vec.capacity() >= 11);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn reserve_exact(&mut self, additional: usize) {
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)
}
}
}
/// Shrinks the capacity of the vector as much as possible.
///
/// It will drop down as close as possible to the length but the allocator
/// may still inform the vector that there is space for a few more elements.
///
/// # Examples
///
/// ```
/// let mut vec = Vec::with_capacity(10);
/// vec.push_all(&[1, 2, 3]);
/// 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;
}
}
/// Convert 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()`.
#[unstable(feature = "collections")]
pub fn into_boxed_slice(mut self) -> Box<[T]> {
self.shrink_to_fit();
unsafe {
let xs: Box<[T]> = Box::from_raw(&mut *self);
mem::forget(self);
xs
}
}
/// Shorten a vector, dropping excess elements.
///
/// If `len` is greater than the vector's current length, this has no
/// effect.
///
/// # Examples
///
/// ```
/// let mut vec = vec![1, 2, 3, 4];
/// vec.truncate(2);
/// assert_eq!(vec, [1, 2]);
/// ```
#[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.
self.len -= 1;
ptr::read(self.get_unchecked(self.len));
}
}
}
/// Returns a mutable slice of the elements of `self`.
///
/// # Examples
///
/// ```
/// fn foo(slice: &mut [i32]) {}
///
/// let mut vec = vec![1, 2];
/// foo(vec.as_mut_slice());
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn as_mut_slice(&mut self) -> &mut [T] {
unsafe {
let ptr = *self.ptr;
assume(!ptr.is_null());
mem::transmute(RawSlice {
data: ptr,
len: self.len,
})
}
}
/// 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]
#[stable(feature = "rust1", since = "1.0.0")]
pub 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 {
(ptr as usize + self.len()) 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 }
}
}
/// Sets the length of a vector.
///
/// This will explicitly set the size of the vector, without actually
/// modifying its buffers, so it is up to the caller to ensure that the
/// vector is actually the specified size.
///
/// # Examples
///
/// ```
/// let mut v = vec![1, 2, 3, 4];
/// unsafe {
/// v.set_len(1);
/// }
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub unsafe fn set_len(&mut self, len: usize) {
self.len = len;
}
/// Removes an element from anywhere in the vector and return it, replacing
/// it with the last element.
///
/// This does not preserve ordering, but is O(1).
///
/// # Panics
///
/// Panics if `index` is out of bounds.
///
/// # Examples
///
/// ```
/// let mut v = vec!["foo", "bar", "baz", "qux"];
///
/// assert_eq!(v.swap_remove(1), "bar");
/// assert_eq!(v, ["foo", "qux", "baz"]);
///
/// assert_eq!(v.swap_remove(0), "foo");
/// assert_eq!(v, ["baz", "qux"]);
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn swap_remove(&mut self, index: usize) -> T {
let length = self.len();
self.swap(index, length - 1);
self.pop().unwrap()
}
/// Inserts an element at position `index` within the vector, shifting all
/// elements after position `i` one position to the right.
///
/// # Panics
///
/// Panics if `index` is not between `0` and the vector's length (both
/// bounds inclusive).
///
/// # 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.offset(1), &*p, 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 `i` 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, &*ptr.offset(1), 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
///
/// ```rust
/// 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) {
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");
unsafe { mem::forget(value); }
return
}
if self.len == self.cap {
let old_size = self.cap * mem::size_of::<T>();
let size = max(old_size, 2 * mem::size_of::<T>()) * 2;
if old_size > size { panic!("capacity overflow") }
unsafe {
let ptr = alloc_or_realloc(*self.ptr, old_size, size);
if ptr.is_null() { ::alloc::oom() }
self.ptr = Unique::new(ptr);
}
self.cap = max(self.cap, 2) * 2;
}
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
///
/// ```rust
/// let mut vec = vec![1, 2, 3];
/// assert_eq!(vec.pop(), Some(3));
/// assert_eq!(vec, [1, 2]);
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn pop(&mut self) -> Option<T> {
if self.len == 0 {
None
} else {
unsafe {
self.len -= 1;
Some(ptr::read(self.get_unchecked(self.len())))
}
}
}
/// Moves all the elements of `other` into `Self`, leaving `other` empty.
///
/// # Panics
///
/// Panics if the number of elements in the vector overflows a `usize`.
///
/// # Examples
///
/// ```
/// let mut vec = vec![1, 2, 3];
/// let mut vec2 = vec![4, 5, 6];
/// vec.append(&mut vec2);
/// assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
/// assert_eq!(vec2, []);
/// ```
#[inline]
#[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(
self.get_unchecked_mut(len),
other.as_ptr(),
other.len());
}
self.len += other.len();
unsafe { other.set_len(0); }
}
/// Creates a draining iterator that clears the `Vec` and iterates over
/// the removed items from start to end.
///
/// # Examples
///
/// ```
/// let mut v = vec!["a".to_string(), "b".to_string()];
/// for s in v.drain() {
/// // s has type String, not &String
/// println!("{}", s);
/// }
/// assert!(v.is_empty());
/// ```
#[inline]
#[unstable(feature = "collections",
reason = "matches collection reform specification, waiting for dust to settle")]
pub fn drain(&mut self) -> Drain<T> {
unsafe {
let begin = *self.ptr as *const T;
let end = if mem::size_of::<T>() == 0 {
(*self.ptr as usize + self.len()) as *const T
} else {
(*self.ptr).offset(self.len() as isize) as *const T
};
self.set_len(0);
Drain {
ptr: begin,
end: end,
marker: PhantomData,
}
}
}
/// 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
///
/// ```
/// let v = vec![0, 1, 2];
/// let w = v.map_in_place(|i| i + 3);
/// assert_eq!(w.as_slice(), [3, 4, 5].as_slice());
///
/// #[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.as_slice(), [Newtype(0x11), Newtype(0x22)].as_slice());
/// ```
#[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,
};
unsafe { 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
///
/// ```
/// 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(
other.as_mut_ptr(),
self.as_ptr().offset(at as isize),
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
///
/// ```
/// 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
///
/// ```
/// 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 = 1;
let mut w = 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
////////////////////////////////////////////////////////////////////////////////
#[unstable(feature = "collections")]
impl<T:Clone> Clone for Vec<T> {
fn clone(&self) -> Vec<T> { ::slice::SliceExt::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.as_slice()
}
}
#[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.as_mut_slice()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T> ops::Deref for Vec<T> {
type Target = [T];
fn deref(&self) -> &[T] { self.as_slice() }
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T> ops::DerefMut for Vec<T> {
fn deref_mut(&mut self) -> &mut [T] { self.as_mut_slice() }
}
#[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>;
fn into_iter(self) -> IntoIter<T> {
self.into_iter()
}
}
#[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()
}
}
#[unstable(feature = "collections", reason = "waiting on Extend stability")]
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_eq2! { Vec<A>, &'b [B] }
__impl_slice_eq2! { Vec<A>, &'b mut [B] }
__impl_slice_eq2! { Cow<'a, [A]>, &'b [B], Clone }
__impl_slice_eq2! { Cow<'a, [A]>, &'b mut [B], Clone }
__impl_slice_eq2! { 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_eq2! { Vec<A>, [B; $N] }
__impl_slice_eq2! { Vec<A>, &'b [B; $N] }
// __impl_slice_eq2! { Vec<A>, &'b mut [B; $N] }
// __impl_slice_eq2! { Cow<'a, [A]>, [B; $N], Clone }
// __impl_slice_eq2! { Cow<'a, [A]>, &'b [B; $N], Clone }
// __impl_slice_eq2! { 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)
}
}
impl<T> AsSlice<T> for Vec<T> {
/// Returns a slice into `self`.
///
/// # Examples
///
/// ```
/// fn foo(slice: &[i32]) {}
///
/// let vec = vec![1, 2];
/// foo(vec.as_slice());
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
fn as_slice(&self) -> &[T] {
unsafe {
let p = *self.ptr;
assume(p != 0 as *mut T);
mem::transmute(RawSlice {
data: p,
len: self.len
})
}
}
}
#[unstable(feature = "collections",
reason = "recent addition, needs more experience")]
impl<'a, T: Clone> Add<&'a [T]> for Vec<T> {
type Output = Vec<T>;
#[inline]
fn add(mut self, rhs: &[T]) -> Vec<T> {
self.push_all(rhs);
self
}
}
#[unsafe_destructor]
#[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 {
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)
}
}
////////////////////////////////////////////////////////////////////////////////
// Clone-on-write
////////////////////////////////////////////////////////////////////////////////
/// A clone-on-write vector
#[deprecated(since = "1.0.0", reason = "use Cow<'a, [T]> instead")]
#[unstable(feature = "collections")]
pub type CowVec<'a, T> = Cow<'a, [T]>;
#[unstable(feature = "collections")]
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 = mem::transmute(self.ptr as usize + 1);
// 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))
}
}
#[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 = mem::transmute(self.end as usize - 1);
// 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> {}
#[unsafe_destructor]
#[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);
}
}
}
}
/// An iterator that drains a vector.
#[unsafe_no_drop_flag]
#[unstable(feature = "collections",
reason = "recently added as part of collections reform 2")]
pub struct Drain<'a, T:'a> {
ptr: *const T,
end: *const T,
marker: PhantomData<&'a 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> {
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 = mem::transmute(self.ptr as usize + 1);
// 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))
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, T> DoubleEndedIterator for Drain<'a, 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 = mem::transmute(self.end as usize - 1);
// Use a non-null pointer value
Some(ptr::read(EMPTY as *mut T))
} else {
self.end = self.end.offset(-1);
Some(ptr::read(self.end))
}
}
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, T> ExactSizeIterator for Drain<'a, T> {}
#[unsafe_destructor]
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, T> Drop for Drain<'a, T> {
fn drop(&mut self) {
// self.ptr == self.end == null if drop has already been called,
// so we can use #[unsafe_no_drop_flag].
// destroy the remaining elements
for _x in self.by_ref() {}
}
}
////////////////////////////////////////////////////////////////////////////////
// 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.
#[unsafe_destructor]
#[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;
}
}
/// Convert a slice to a wrapper type providing a `&Vec<T>` reference.
#[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)>>,
}
#[unsafe_destructor]
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.
}
}
}
#[unsafe_destructor]
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;
}
}
}
}
#[cfg(test)]
mod tests {
use prelude::*;
use core::mem::size_of;
use core::iter::repeat;
use test::Bencher;
use super::as_vec;
struct DropCounter<'a> {
count: &'a mut u32
}
#[unsafe_destructor]
impl<'a> Drop for DropCounter<'a> {
fn drop(&mut self) {
*self.count += 1;
}
}
#[test]
fn test_as_vec() {
let xs = [1u8, 2u8, 3u8];
assert_eq!(&**as_vec(&xs), xs);
}
#[test]
fn test_as_vec_dtor() {
let (mut count_x, mut count_y) = (0, 0);
{
let xs = &[DropCounter { count: &mut count_x }, DropCounter { count: &mut count_y }];
assert_eq!(as_vec(xs).len(), 2);
}
assert_eq!(count_x, 1);
assert_eq!(count_y, 1);
}
#[test]
fn test_small_vec_struct() {
assert!(size_of::<Vec<u8>>() == size_of::<usize>() * 3);
}
#[test]
fn test_double_drop() {
struct TwoVec<T> {
x: Vec<T>,
y: Vec<T>
}
let (mut count_x, mut count_y) = (0, 0);
{
let mut tv = TwoVec {
x: Vec::new(),
y: Vec::new()
};
tv.x.push(DropCounter {count: &mut count_x});
tv.y.push(DropCounter {count: &mut count_y});
// If Vec had a drop flag, here is where it would be zeroed.
// Instead, it should rely on its internal state to prevent
// doing anything significant when dropped multiple times.
drop(tv.x);
// Here tv goes out of scope, tv.y should be dropped, but not tv.x.
}
assert_eq!(count_x, 1);
assert_eq!(count_y, 1);
}
#[test]
fn test_reserve() {
let mut v = Vec::new();
assert_eq!(v.capacity(), 0);
v.reserve(2);
assert!(v.capacity() >= 2);
for i in 0..16 {
v.push(i);
}
assert!(v.capacity() >= 16);
v.reserve(16);
assert!(v.capacity() >= 32);
v.push(16);
v.reserve(16);
assert!(v.capacity() >= 33)
}
#[test]
fn test_extend() {
let mut v = Vec::new();
let mut w = Vec::new();
v.extend(0..3);
for i in 0..3 { w.push(i) }
assert_eq!(v, w);
v.extend(3..10);
for i in 3..10 { w.push(i) }
assert_eq!(v, w);
}
#[test]
fn test_slice_from_mut() {
let mut values = vec![1, 2, 3, 4, 5];
{
let slice = &mut values[2 ..];
assert!(slice == [3, 4, 5]);
for p in slice {
*p += 2;
}
}
assert!(values == [1, 2, 5, 6, 7]);
}
#[test]
fn test_slice_to_mut() {
let mut values = vec![1, 2, 3, 4, 5];
{
let slice = &mut values[.. 2];
assert!(slice == [1, 2]);
for p in slice {
*p += 1;
}
}
assert!(values == [2, 3, 3, 4, 5]);
}
#[test]
fn test_split_at_mut() {
let mut values = vec![1, 2, 3, 4, 5];
{
let (left, right) = values.split_at_mut(2);
{
let left: &[_] = left;
assert!(&left[..left.len()] == &[1, 2]);
}
for p in left {
*p += 1;
}
{
let right: &[_] = right;
assert!(&right[..right.len()] == &[3, 4, 5]);
}
for p in right {
*p += 2;
}
}
assert_eq!(values, [2, 3, 5, 6, 7]);
}
#[test]
fn test_clone() {
let v: Vec<i32> = vec![];
let w = vec!(1, 2, 3);
assert_eq!(v, v.clone());
let z = w.clone();
assert_eq!(w, z);
// they should be disjoint in memory.
assert!(w.as_ptr() != z.as_ptr())
}
#[test]
fn test_clone_from() {
let mut v = vec!();
let three: Vec<Box<_>> = vec!(box 1, box 2, box 3);
let two: Vec<Box<_>> = vec!(box 4, box 5);
// zero, long
v.clone_from(&three);
assert_eq!(v, three);
// equal
v.clone_from(&three);
assert_eq!(v, three);
// long, short
v.clone_from(&two);
assert_eq!(v, two);
// short, long
v.clone_from(&three);
assert_eq!(v, three)
}
#[test]
fn test_retain() {
let mut vec = vec![1, 2, 3, 4];
vec.retain(|&x| x % 2 == 0);
assert_eq!(vec, [2, 4]);
}
#[test]
fn zero_sized_values() {
let mut v = Vec::new();
assert_eq!(v.len(), 0);
v.push(());
assert_eq!(v.len(), 1);
v.push(());
assert_eq!(v.len(), 2);
assert_eq!(v.pop(), Some(()));
assert_eq!(v.pop(), Some(()));
assert_eq!(v.pop(), None);
assert_eq!(v.iter().count(), 0);
v.push(());
assert_eq!(v.iter().count(), 1);
v.push(());
assert_eq!(v.iter().count(), 2);
for &() in &v {}
assert_eq!(v.iter_mut().count(), 2);
v.push(());
assert_eq!(v.iter_mut().count(), 3);
v.push(());
assert_eq!(v.iter_mut().count(), 4);
for &mut () in &mut v {}
unsafe { v.set_len(0); }
assert_eq!(v.iter_mut().count(), 0);
}
#[test]
fn test_partition() {
assert_eq!(vec![].into_iter().partition(|x: &i32| *x < 3), (vec![], vec![]));
assert_eq!(vec![1, 2, 3].into_iter().partition(|x| *x < 4), (vec![1, 2, 3], vec![]));
assert_eq!(vec![1, 2, 3].into_iter().partition(|x| *x < 2), (vec![1], vec![2, 3]));
assert_eq!(vec![1, 2, 3].into_iter().partition(|x| *x < 0), (vec![], vec![1, 2, 3]));
}
#[test]
fn test_zip_unzip() {
let z1 = vec![(1, 4), (2, 5), (3, 6)];
let (left, right): (Vec<_>, Vec<_>) = z1.iter().cloned().unzip();
assert_eq!((1, 4), (left[0], right[0]));
assert_eq!((2, 5), (left[1], right[1]));
assert_eq!((3, 6), (left[2], right[2]));
}
#[test]
fn test_unsafe_ptrs() {
unsafe {
// Test on-stack copy-from-buf.
let a = [1, 2, 3];
let ptr = a.as_ptr();
let b = Vec::from_raw_buf(ptr, 3);
assert_eq!(b, [1, 2, 3]);
// Test on-heap copy-from-buf.
let c = vec![1, 2, 3, 4, 5];
let ptr = c.as_ptr();
let d = Vec::from_raw_buf(ptr, 5);
assert_eq!(d, [1, 2, 3, 4, 5]);
}
}
#[test]
fn test_vec_truncate_drop() {
static mut drops: u32 = 0;
struct Elem(i32);
impl Drop for Elem {
fn drop(&mut self) {
unsafe { drops += 1; }
}
}
let mut v = vec![Elem(1), Elem(2), Elem(3), Elem(4), Elem(5)];
assert_eq!(unsafe { drops }, 0);
v.truncate(3);
assert_eq!(unsafe { drops }, 2);
v.truncate(0);
assert_eq!(unsafe { drops }, 5);
}
#[test]
#[should_panic]
fn test_vec_truncate_fail() {
struct BadElem(i32);
impl Drop for BadElem {
fn drop(&mut self) {
let BadElem(ref mut x) = *self;
if *x == 0xbadbeef {
panic!("BadElem panic: 0xbadbeef")
}
}
}
let mut v = vec![BadElem(1), BadElem(2), BadElem(0xbadbeef), BadElem(4)];
v.truncate(0);
}
#[test]
fn test_index() {
let vec = vec![1, 2, 3];
assert!(vec[1] == 2);
}
#[test]
#[should_panic]
fn test_index_out_of_bounds() {
let vec = vec![1, 2, 3];
let _ = vec[3];
}
#[test]
#[should_panic]
fn test_slice_out_of_bounds_1() {
let x = vec![1, 2, 3, 4, 5];
&x[-1..];
}
#[test]
#[should_panic]
fn test_slice_out_of_bounds_2() {
let x = vec![1, 2, 3, 4, 5];
&x[..6];
}
#[test]
#[should_panic]
fn test_slice_out_of_bounds_3() {
let x = vec![1, 2, 3, 4, 5];
&x[-1..4];
}
#[test]
#[should_panic]
fn test_slice_out_of_bounds_4() {
let x = vec![1, 2, 3, 4, 5];
&x[1..6];
}
#[test]
#[should_panic]
fn test_slice_out_of_bounds_5() {
let x = vec![1, 2, 3, 4, 5];
&x[3..2];
}
#[test]
#[should_panic]
fn test_swap_remove_empty() {
let mut vec= Vec::<i32>::new();
vec.swap_remove(0);
}
#[test]
fn test_move_iter_unwrap() {
let mut vec = Vec::with_capacity(7);
vec.push(1);
vec.push(2);
let ptr = vec.as_ptr();
vec = vec.into_iter().into_inner();
assert_eq!(vec.as_ptr(), ptr);
assert_eq!(vec.capacity(), 7);
assert_eq!(vec.len(), 0);
}
#[test]
#[should_panic]
fn test_map_in_place_incompatible_types_fail() {
let v = vec![0, 1, 2];
v.map_in_place(|_| ());
}
#[test]
fn test_map_in_place() {
let v = vec![0, 1, 2];
assert_eq!(v.map_in_place(|i: u32| i as i32 - 1), [-1, 0, 1]);
}
#[test]
fn test_map_in_place_zero_sized() {
let v = vec![(), ()];
#[derive(PartialEq, Debug)]
struct ZeroSized;
assert_eq!(v.map_in_place(|_| ZeroSized), [ZeroSized, ZeroSized]);
}
#[test]
fn test_map_in_place_zero_drop_count() {
use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
#[derive(Clone, PartialEq, Debug)]
struct Nothing;
impl Drop for Nothing { fn drop(&mut self) { } }
#[derive(Clone, PartialEq, Debug)]
struct ZeroSized;
impl Drop for ZeroSized {
fn drop(&mut self) {
DROP_COUNTER.fetch_add(1, Ordering::Relaxed);
}
}
const NUM_ELEMENTS: usize = 2;
static DROP_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
let v = repeat(Nothing).take(NUM_ELEMENTS).collect::<Vec<_>>();
DROP_COUNTER.store(0, Ordering::Relaxed);
let v = v.map_in_place(|_| ZeroSized);
assert_eq!(DROP_COUNTER.load(Ordering::Relaxed), 0);
drop(v);
assert_eq!(DROP_COUNTER.load(Ordering::Relaxed), NUM_ELEMENTS);
}
#[test]
fn test_move_items() {
let vec = vec![1, 2, 3];
let mut vec2 = vec![];
for i in vec {
vec2.push(i);
}
assert_eq!(vec2, [1, 2, 3]);
}
#[test]
fn test_move_items_reverse() {
let vec = vec![1, 2, 3];
let mut vec2 = vec![];
for i in vec.into_iter().rev() {
vec2.push(i);
}
assert_eq!(vec2, [3, 2, 1]);
}
#[test]
fn test_move_items_zero_sized() {
let vec = vec![(), (), ()];
let mut vec2 = vec![];
for i in vec {
vec2.push(i);
}
assert_eq!(vec2, [(), (), ()]);
}
#[test]
fn test_drain_items() {
let mut vec = vec![1, 2, 3];
let mut vec2 = vec![];
for i in vec.drain() {
vec2.push(i);
}
assert_eq!(vec, []);
assert_eq!(vec2, [ 1, 2, 3 ]);
}
#[test]
fn test_drain_items_reverse() {
let mut vec = vec![1, 2, 3];
let mut vec2 = vec![];
for i in vec.drain().rev() {
vec2.push(i);
}
assert_eq!(vec, []);
assert_eq!(vec2, [3, 2, 1]);
}
#[test]
fn test_drain_items_zero_sized() {
let mut vec = vec![(), (), ()];
let mut vec2 = vec![];
for i in vec.drain() {
vec2.push(i);
}
assert_eq!(vec, []);
assert_eq!(vec2, [(), (), ()]);
}
#[test]
fn test_into_boxed_slice() {
let xs = vec![1, 2, 3];
let ys = xs.into_boxed_slice();
assert_eq!(&*ys, [1, 2, 3]);
}
#[test]
fn test_append() {
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, []);
}
#[test]
fn test_split_off() {
let mut vec = vec![1, 2, 3, 4, 5, 6];
let vec2 = vec.split_off(4);
assert_eq!(vec, [1, 2, 3, 4]);
assert_eq!(vec2, [5, 6]);
}
#[bench]
fn bench_new(b: &mut Bencher) {
b.iter(|| {
let v: Vec<u32> = Vec::new();
assert_eq!(v.len(), 0);
assert_eq!(v.capacity(), 0);
})
}
fn do_bench_with_capacity(b: &mut Bencher, src_len: usize) {
b.bytes = src_len as u64;
b.iter(|| {
let v: Vec<u32> = Vec::with_capacity(src_len);
assert_eq!(v.len(), 0);
assert_eq!(v.capacity(), src_len);
})
}
#[bench]
fn bench_with_capacity_0000(b: &mut Bencher) {
do_bench_with_capacity(b, 0)
}
#[bench]
fn bench_with_capacity_0010(b: &mut Bencher) {
do_bench_with_capacity(b, 10)
}
#[bench]
fn bench_with_capacity_0100(b: &mut Bencher) {
do_bench_with_capacity(b, 100)
}
#[bench]
fn bench_with_capacity_1000(b: &mut Bencher) {
do_bench_with_capacity(b, 1000)
}
fn do_bench_from_fn(b: &mut Bencher, src_len: usize) {
b.bytes = src_len as u64;
b.iter(|| {
let dst = (0..src_len).collect::<Vec<_>>();
assert_eq!(dst.len(), src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
})
}
#[bench]
fn bench_from_fn_0000(b: &mut Bencher) {
do_bench_from_fn(b, 0)
}
#[bench]
fn bench_from_fn_0010(b: &mut Bencher) {
do_bench_from_fn(b, 10)
}
#[bench]
fn bench_from_fn_0100(b: &mut Bencher) {
do_bench_from_fn(b, 100)
}
#[bench]
fn bench_from_fn_1000(b: &mut Bencher) {
do_bench_from_fn(b, 1000)
}
fn do_bench_from_elem(b: &mut Bencher, src_len: usize) {
b.bytes = src_len as u64;
b.iter(|| {
let dst: Vec<usize> = repeat(5).take(src_len).collect();
assert_eq!(dst.len(), src_len);
assert!(dst.iter().all(|x| *x == 5));
})
}
#[bench]
fn bench_from_elem_0000(b: &mut Bencher) {
do_bench_from_elem(b, 0)
}
#[bench]
fn bench_from_elem_0010(b: &mut Bencher) {
do_bench_from_elem(b, 10)
}
#[bench]
fn bench_from_elem_0100(b: &mut Bencher) {
do_bench_from_elem(b, 100)
}
#[bench]
fn bench_from_elem_1000(b: &mut Bencher) {
do_bench_from_elem(b, 1000)
}
fn do_bench_from_slice(b: &mut Bencher, src_len: usize) {
let src: Vec<_> = FromIterator::from_iter(0..src_len);
b.bytes = src_len as u64;
b.iter(|| {
let dst = src.clone()[..].to_vec();
assert_eq!(dst.len(), src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_from_slice_0000(b: &mut Bencher) {
do_bench_from_slice(b, 0)
}
#[bench]
fn bench_from_slice_0010(b: &mut Bencher) {
do_bench_from_slice(b, 10)
}
#[bench]
fn bench_from_slice_0100(b: &mut Bencher) {
do_bench_from_slice(b, 100)
}
#[bench]
fn bench_from_slice_1000(b: &mut Bencher) {
do_bench_from_slice(b, 1000)
}
fn do_bench_from_iter(b: &mut Bencher, src_len: usize) {
let src: Vec<_> = FromIterator::from_iter(0..src_len);
b.bytes = src_len as u64;
b.iter(|| {
let dst: Vec<_> = FromIterator::from_iter(src.clone().into_iter());
assert_eq!(dst.len(), src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_from_iter_0000(b: &mut Bencher) {
do_bench_from_iter(b, 0)
}
#[bench]
fn bench_from_iter_0010(b: &mut Bencher) {
do_bench_from_iter(b, 10)
}
#[bench]
fn bench_from_iter_0100(b: &mut Bencher) {
do_bench_from_iter(b, 100)
}
#[bench]
fn bench_from_iter_1000(b: &mut Bencher) {
do_bench_from_iter(b, 1000)
}
fn do_bench_extend(b: &mut Bencher, dst_len: usize, src_len: usize) {
let dst: Vec<_> = FromIterator::from_iter(0..dst_len);
let src: Vec<_> = FromIterator::from_iter(dst_len..dst_len + src_len);
b.bytes = src_len as u64;
b.iter(|| {
let mut dst = dst.clone();
dst.extend(src.clone().into_iter());
assert_eq!(dst.len(), dst_len + src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_extend_0000_0000(b: &mut Bencher) {
do_bench_extend(b, 0, 0)
}
#[bench]
fn bench_extend_0000_0010(b: &mut Bencher) {
do_bench_extend(b, 0, 10)
}
#[bench]
fn bench_extend_0000_0100(b: &mut Bencher) {
do_bench_extend(b, 0, 100)
}
#[bench]
fn bench_extend_0000_1000(b: &mut Bencher) {
do_bench_extend(b, 0, 1000)
}
#[bench]
fn bench_extend_0010_0010(b: &mut Bencher) {
do_bench_extend(b, 10, 10)
}
#[bench]
fn bench_extend_0100_0100(b: &mut Bencher) {
do_bench_extend(b, 100, 100)
}
#[bench]
fn bench_extend_1000_1000(b: &mut Bencher) {
do_bench_extend(b, 1000, 1000)
}
fn do_bench_push_all(b: &mut Bencher, dst_len: usize, src_len: usize) {
let dst: Vec<_> = FromIterator::from_iter(0..dst_len);
let src: Vec<_> = FromIterator::from_iter(dst_len..dst_len + src_len);
b.bytes = src_len as u64;
b.iter(|| {
let mut dst = dst.clone();
dst.push_all(&src);
assert_eq!(dst.len(), dst_len + src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_push_all_0000_0000(b: &mut Bencher) {
do_bench_push_all(b, 0, 0)
}
#[bench]
fn bench_push_all_0000_0010(b: &mut Bencher) {
do_bench_push_all(b, 0, 10)
}
#[bench]
fn bench_push_all_0000_0100(b: &mut Bencher) {
do_bench_push_all(b, 0, 100)
}
#[bench]
fn bench_push_all_0000_1000(b: &mut Bencher) {
do_bench_push_all(b, 0, 1000)
}
#[bench]
fn bench_push_all_0010_0010(b: &mut Bencher) {
do_bench_push_all(b, 10, 10)
}
#[bench]
fn bench_push_all_0100_0100(b: &mut Bencher) {
do_bench_push_all(b, 100, 100)
}
#[bench]
fn bench_push_all_1000_1000(b: &mut Bencher) {
do_bench_push_all(b, 1000, 1000)
}
fn do_bench_push_all_move(b: &mut Bencher, dst_len: usize, src_len: usize) {
let dst: Vec<_> = FromIterator::from_iter(0..dst_len);
let src: Vec<_> = FromIterator::from_iter(dst_len..dst_len + src_len);
b.bytes = src_len as u64;
b.iter(|| {
let mut dst = dst.clone();
dst.extend(src.clone().into_iter());
assert_eq!(dst.len(), dst_len + src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_push_all_move_0000_0000(b: &mut Bencher) {
do_bench_push_all_move(b, 0, 0)
}
#[bench]
fn bench_push_all_move_0000_0010(b: &mut Bencher) {
do_bench_push_all_move(b, 0, 10)
}
#[bench]
fn bench_push_all_move_0000_0100(b: &mut Bencher) {
do_bench_push_all_move(b, 0, 100)
}
#[bench]
fn bench_push_all_move_0000_1000(b: &mut Bencher) {
do_bench_push_all_move(b, 0, 1000)
}
#[bench]
fn bench_push_all_move_0010_0010(b: &mut Bencher) {
do_bench_push_all_move(b, 10, 10)
}
#[bench]
fn bench_push_all_move_0100_0100(b: &mut Bencher) {
do_bench_push_all_move(b, 100, 100)
}
#[bench]
fn bench_push_all_move_1000_1000(b: &mut Bencher) {
do_bench_push_all_move(b, 1000, 1000)
}
fn do_bench_clone(b: &mut Bencher, src_len: usize) {
let src: Vec<usize> = FromIterator::from_iter(0..src_len);
b.bytes = src_len as u64;
b.iter(|| {
let dst = src.clone();
assert_eq!(dst.len(), src_len);
assert!(dst.iter().enumerate().all(|(i, x)| i == *x));
});
}
#[bench]
fn bench_clone_0000(b: &mut Bencher) {
do_bench_clone(b, 0)
}
#[bench]
fn bench_clone_0010(b: &mut Bencher) {
do_bench_clone(b, 10)
}
#[bench]
fn bench_clone_0100(b: &mut Bencher) {
do_bench_clone(b, 100)
}
#[bench]
fn bench_clone_1000(b: &mut Bencher) {
do_bench_clone(b, 1000)
}
fn do_bench_clone_from(b: &mut Bencher, times: usize, dst_len: usize, src_len: usize) {
let dst: Vec<_> = FromIterator::from_iter(0..src_len);
let src: Vec<_> = FromIterator::from_iter(dst_len..dst_len + src_len);
b.bytes = (times * src_len) as u64;
b.iter(|| {
let mut dst = dst.clone();
for _ in 0..times {
dst.clone_from(&src);
assert_eq!(dst.len(), src_len);
assert!(dst.iter().enumerate().all(|(i, x)| dst_len + i == *x));
}
});
}
#[bench]
fn bench_clone_from_01_0000_0000(b: &mut Bencher) {
do_bench_clone_from(b, 1, 0, 0)
}
#[bench]
fn bench_clone_from_01_0000_0010(b: &mut Bencher) {
do_bench_clone_from(b, 1, 0, 10)
}
#[bench]
fn bench_clone_from_01_0000_0100(b: &mut Bencher) {
do_bench_clone_from(b, 1, 0, 100)
}
#[bench]
fn bench_clone_from_01_0000_1000(b: &mut Bencher) {
do_bench_clone_from(b, 1, 0, 1000)
}
#[bench]
fn bench_clone_from_01_0010_0010(b: &mut Bencher) {
do_bench_clone_from(b, 1, 10, 10)
}
#[bench]
fn bench_clone_from_01_0100_0100(b: &mut Bencher) {
do_bench_clone_from(b, 1, 100, 100)
}
#[bench]
fn bench_clone_from_01_1000_1000(b: &mut Bencher) {
do_bench_clone_from(b, 1, 1000, 1000)
}
#[bench]
fn bench_clone_from_01_0010_0100(b: &mut Bencher) {
do_bench_clone_from(b, 1, 10, 100)
}
#[bench]
fn bench_clone_from_01_0100_1000(b: &mut Bencher) {
do_bench_clone_from(b, 1, 100, 1000)
}
#[bench]
fn bench_clone_from_01_0010_0000(b: &mut Bencher) {
do_bench_clone_from(b, 1, 10, 0)
}
#[bench]
fn bench_clone_from_01_0100_0010(b: &mut Bencher) {
do_bench_clone_from(b, 1, 100, 10)
}
#[bench]
fn bench_clone_from_01_1000_0100(b: &mut Bencher) {
do_bench_clone_from(b, 1, 1000, 100)
}
#[bench]
fn bench_clone_from_10_0000_0000(b: &mut Bencher) {
do_bench_clone_from(b, 10, 0, 0)
}
#[bench]
fn bench_clone_from_10_0000_0010(b: &mut Bencher) {
do_bench_clone_from(b, 10, 0, 10)
}
#[bench]
fn bench_clone_from_10_0000_0100(b: &mut Bencher) {
do_bench_clone_from(b, 10, 0, 100)
}
#[bench]
fn bench_clone_from_10_0000_1000(b: &mut Bencher) {
do_bench_clone_from(b, 10, 0, 1000)
}
#[bench]
fn bench_clone_from_10_0010_0010(b: &mut Bencher) {
do_bench_clone_from(b, 10, 10, 10)
}
#[bench]
fn bench_clone_from_10_0100_0100(b: &mut Bencher) {
do_bench_clone_from(b, 10, 100, 100)
}
#[bench]
fn bench_clone_from_10_1000_1000(b: &mut Bencher) {
do_bench_clone_from(b, 10, 1000, 1000)
}
#[bench]
fn bench_clone_from_10_0010_0100(b: &mut Bencher) {
do_bench_clone_from(b, 10, 10, 100)
}
#[bench]
fn bench_clone_from_10_0100_1000(b: &mut Bencher) {
do_bench_clone_from(b, 10, 100, 1000)
}
#[bench]
fn bench_clone_from_10_0010_0000(b: &mut Bencher) {
do_bench_clone_from(b, 10, 10, 0)
}
#[bench]
fn bench_clone_from_10_0100_0010(b: &mut Bencher) {
do_bench_clone_from(b, 10, 100, 10)
}
#[bench]
fn bench_clone_from_10_1000_0100(b: &mut Bencher) {
do_bench_clone_from(b, 10, 1000, 100)
}
}
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