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rust/src/liballoc/tests/slice.rs
kennytm 42de36d4aa
Rollup merge of #48639 - varkor:sort_by_key-cached, r=bluss 
Add slice::sort_by_cached_key as a memoised sort_by_key

At present, `slice::sort_by_key` calls its key function twice for each comparison that is made. When the key function is expensive (which can often be the case when `sort_by_key` is chosen over `sort_by`), this can lead to very suboptimal behaviour.

To address this, I've introduced a new slice method, `sort_by_cached_key`, which has identical semantic behaviour to `sort_by_key`, except that it guarantees the key function will only be called once per element.

Where there are `n` elements and the key function is `O(m)`:
- `slice::sort_by_cached_key` time complexity is `O(m n log m n)`, compared to `slice::sort_by_key`'s `O(m n + n log n)`.
- `slice::sort_by_cached_key` space complexity remains at `O(n + m)`. (Technically, it now reserves a slice of size `n`, whereas before it reserved a slice of size `n/2`.)

`slice::sort_unstable_by_key` has not been given an analogue, as it is important that unstable sorts are in-place, which is not a property that is guaranteed here. However, this also means that `slice::sort_unstable_by_key` is likely to be slower than `slice::sort_by_cached_key` when the key function does not have negligible complexity. We might want to explore this trade-off further in the future.

Benchmarks (for a vector of 100 `i32`s):
```
# Lexicographic: `|x| x.to_string()`
test bench_sort_by_key ... bench:      112,638 ns/iter (+/- 19,563)
test bench_sort_by_cached_key ... bench:       15,038 ns/iter (+/- 4,814)

# Identity: `|x| *x`
test bench_sort_by_key ... bench:        1,346 ns/iter (+/- 238)
test bench_sort_by_cached_key ... bench:        1,839 ns/iter (+/- 765)

# Power: `|x| x.pow(31)`
test bench_sort_by_key ... bench:        3,624 ns/iter (+/- 738)
test bench_sort_by_cached_key ... bench:        1,997 ns/iter (+/- 311)

# Abs: `|x| x.abs()`
test bench_sort_by_key ... bench:        1,546 ns/iter (+/- 174)
test bench_sort_by_cached_key ... bench:        1,668 ns/iter (+/- 790)
```
(So it seems functions that are single operations do perform slightly worse with this method, but for pretty much any more complex key, you're better off with this optimisation.)

I've definitely found myself using expensive keys in the past and wishing this optimisation was made (e.g. for https://github.com/rust-lang/rust/pull/47415). This feels like both desirable and expected behaviour, at the small cost of slightly more stack allocation and minute degradation in performance for extremely trivial keys.

Resolves #34447.
2018-03-27 10:47:44 +02:00

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// Copyright 2012-2015 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.
use std::cell::Cell;
use std::cmp::Ordering::{Equal, Greater, Less};
use std::cmp::Ordering;
use std::mem;
use std::panic;
use std::rc::Rc;
use std::sync::atomic::Ordering::Relaxed;
use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize};
use std::thread;
use rand::{Rng, thread_rng};
fn square(n: usize) -> usize {
n * n
}
fn is_odd(n: &usize) -> bool {
*n % 2 == 1
}
#[test]
fn test_from_fn() {
// Test on-stack from_fn.
let mut v: Vec<_> = (0..3).map(square).collect();
{
let v = v;
assert_eq!(v.len(), 3);
assert_eq!(v[0], 0);
assert_eq!(v[1], 1);
assert_eq!(v[2], 4);
}
// Test on-heap from_fn.
v = (0..5).map(square).collect();
{
let v = v;
assert_eq!(v.len(), 5);
assert_eq!(v[0], 0);
assert_eq!(v[1], 1);
assert_eq!(v[2], 4);
assert_eq!(v[3], 9);
assert_eq!(v[4], 16);
}
}
#[test]
fn test_from_elem() {
// Test on-stack from_elem.
let mut v = vec![10, 10];
{
let v = v;
assert_eq!(v.len(), 2);
assert_eq!(v[0], 10);
assert_eq!(v[1], 10);
}
// Test on-heap from_elem.
v = vec![20; 6];
{
let v = &v[..];
assert_eq!(v[0], 20);
assert_eq!(v[1], 20);
assert_eq!(v[2], 20);
assert_eq!(v[3], 20);
assert_eq!(v[4], 20);
assert_eq!(v[5], 20);
}
}
#[test]
fn test_is_empty() {
let xs: [i32; 0] = [];
assert!(xs.is_empty());
assert!(![0].is_empty());
}
#[test]
fn test_len_divzero() {
type Z = [i8; 0];
let v0: &[Z] = &[];
let v1: &[Z] = &[[]];
let v2: &[Z] = &[[], []];
assert_eq!(mem::size_of::<Z>(), 0);
assert_eq!(v0.len(), 0);
assert_eq!(v1.len(), 1);
assert_eq!(v2.len(), 2);
}
#[test]
fn test_get() {
let mut a = vec![11];
assert_eq!(a.get(1), None);
a = vec![11, 12];
assert_eq!(a.get(1).unwrap(), &12);
a = vec![11, 12, 13];
assert_eq!(a.get(1).unwrap(), &12);
}
#[test]
fn test_first() {
let mut a = vec![];
assert_eq!(a.first(), None);
a = vec![11];
assert_eq!(a.first().unwrap(), &11);
a = vec![11, 12];
assert_eq!(a.first().unwrap(), &11);
}
#[test]
fn test_first_mut() {
let mut a = vec![];
assert_eq!(a.first_mut(), None);
a = vec![11];
assert_eq!(*a.first_mut().unwrap(), 11);
a = vec![11, 12];
assert_eq!(*a.first_mut().unwrap(), 11);
}
#[test]
fn test_split_first() {
let mut a = vec![11];
let b: &[i32] = &[];
assert!(b.split_first().is_none());
assert_eq!(a.split_first(), Some((&11, b)));
a = vec![11, 12];
let b: &[i32] = &[12];
assert_eq!(a.split_first(), Some((&11, b)));
}
#[test]
fn test_split_first_mut() {
let mut a = vec![11];
let b: &mut [i32] = &mut [];
assert!(b.split_first_mut().is_none());
assert!(a.split_first_mut() == Some((&mut 11, b)));
a = vec![11, 12];
let b: &mut [_] = &mut [12];
assert!(a.split_first_mut() == Some((&mut 11, b)));
}
#[test]
fn test_split_last() {
let mut a = vec![11];
let b: &[i32] = &[];
assert!(b.split_last().is_none());
assert_eq!(a.split_last(), Some((&11, b)));
a = vec![11, 12];
let b: &[_] = &[11];
assert_eq!(a.split_last(), Some((&12, b)));
}
#[test]
fn test_split_last_mut() {
let mut a = vec![11];
let b: &mut [i32] = &mut [];
assert!(b.split_last_mut().is_none());
assert!(a.split_last_mut() == Some((&mut 11, b)));
a = vec![11, 12];
let b: &mut [_] = &mut [11];
assert!(a.split_last_mut() == Some((&mut 12, b)));
}
#[test]
fn test_last() {
let mut a = vec![];
assert_eq!(a.last(), None);
a = vec![11];
assert_eq!(a.last().unwrap(), &11);
a = vec![11, 12];
assert_eq!(a.last().unwrap(), &12);
}
#[test]
fn test_last_mut() {
let mut a = vec![];
assert_eq!(a.last_mut(), None);
a = vec![11];
assert_eq!(*a.last_mut().unwrap(), 11);
a = vec![11, 12];
assert_eq!(*a.last_mut().unwrap(), 12);
}
#[test]
fn test_slice() {
// Test fixed length vector.
let vec_fixed = [1, 2, 3, 4];
let v_a = vec_fixed[1..vec_fixed.len()].to_vec();
assert_eq!(v_a.len(), 3);
assert_eq!(v_a[0], 2);
assert_eq!(v_a[1], 3);
assert_eq!(v_a[2], 4);
// Test on stack.
let vec_stack: &[_] = &[1, 2, 3];
let v_b = vec_stack[1..3].to_vec();
assert_eq!(v_b.len(), 2);
assert_eq!(v_b[0], 2);
assert_eq!(v_b[1], 3);
// Test `Box<[T]>`
let vec_unique = vec![1, 2, 3, 4, 5, 6];
let v_d = vec_unique[1..6].to_vec();
assert_eq!(v_d.len(), 5);
assert_eq!(v_d[0], 2);
assert_eq!(v_d[1], 3);
assert_eq!(v_d[2], 4);
assert_eq!(v_d[3], 5);
assert_eq!(v_d[4], 6);
}
#[test]
fn test_slice_from() {
let vec: &[_] = &[1, 2, 3, 4];
assert_eq!(&vec[..], vec);
let b: &[_] = &[3, 4];
assert_eq!(&vec[2..], b);
let b: &[_] = &[];
assert_eq!(&vec[4..], b);
}
#[test]
fn test_slice_to() {
let vec: &[_] = &[1, 2, 3, 4];
assert_eq!(&vec[..4], vec);
let b: &[_] = &[1, 2];
assert_eq!(&vec[..2], b);
let b: &[_] = &[];
assert_eq!(&vec[..0], b);
}
#[test]
fn test_pop() {
let mut v = vec![5];
let e = v.pop();
assert_eq!(v.len(), 0);
assert_eq!(e, Some(5));
let f = v.pop();
assert_eq!(f, None);
let g = v.pop();
assert_eq!(g, None);
}
#[test]
fn test_swap_remove() {
let mut v = vec![1, 2, 3, 4, 5];
let mut e = v.swap_remove(0);
assert_eq!(e, 1);
assert_eq!(v, [5, 2, 3, 4]);
e = v.swap_remove(3);
assert_eq!(e, 4);
assert_eq!(v, [5, 2, 3]);
}
#[test]
#[should_panic]
fn test_swap_remove_fail() {
let mut v = vec![1];
let _ = v.swap_remove(0);
let _ = v.swap_remove(0);
}
#[test]
fn test_swap_remove_noncopyable() {
// Tests that we don't accidentally run destructors twice.
let mut v: Vec<Box<_>> = Vec::new();
v.push(box 0);
v.push(box 0);
v.push(box 0);
let mut _e = v.swap_remove(0);
assert_eq!(v.len(), 2);
_e = v.swap_remove(1);
assert_eq!(v.len(), 1);
_e = v.swap_remove(0);
assert_eq!(v.len(), 0);
}
#[test]
fn test_push() {
// Test on-stack push().
let mut v = vec![];
v.push(1);
assert_eq!(v.len(), 1);
assert_eq!(v[0], 1);
// Test on-heap push().
v.push(2);
assert_eq!(v.len(), 2);
assert_eq!(v[0], 1);
assert_eq!(v[1], 2);
}
#[test]
fn test_truncate() {
let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
v.truncate(1);
let v = v;
assert_eq!(v.len(), 1);
assert_eq!(*(v[0]), 6);
// If the unsafe block didn't drop things properly, we blow up here.
}
#[test]
fn test_clear() {
let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
v.clear();
assert_eq!(v.len(), 0);
// If the unsafe block didn't drop things properly, we blow up here.
}
#[test]
fn test_retain() {
let mut v = vec![1, 2, 3, 4, 5];
v.retain(is_odd);
assert_eq!(v, [1, 3, 5]);
}
#[test]
fn test_binary_search() {
assert_eq!([1, 2, 3, 4, 5].binary_search(&5).ok(), Some(4));
assert_eq!([1, 2, 3, 4, 5].binary_search(&4).ok(), Some(3));
assert_eq!([1, 2, 3, 4, 5].binary_search(&3).ok(), Some(2));
assert_eq!([1, 2, 3, 4, 5].binary_search(&2).ok(), Some(1));
assert_eq!([1, 2, 3, 4, 5].binary_search(&1).ok(), Some(0));
assert_eq!([2, 4, 6, 8, 10].binary_search(&1).ok(), None);
assert_eq!([2, 4, 6, 8, 10].binary_search(&5).ok(), None);
assert_eq!([2, 4, 6, 8, 10].binary_search(&4).ok(), Some(1));
assert_eq!([2, 4, 6, 8, 10].binary_search(&10).ok(), Some(4));
assert_eq!([2, 4, 6, 8].binary_search(&1).ok(), None);
assert_eq!([2, 4, 6, 8].binary_search(&5).ok(), None);
assert_eq!([2, 4, 6, 8].binary_search(&4).ok(), Some(1));
assert_eq!([2, 4, 6, 8].binary_search(&8).ok(), Some(3));
assert_eq!([2, 4, 6].binary_search(&1).ok(), None);
assert_eq!([2, 4, 6].binary_search(&5).ok(), None);
assert_eq!([2, 4, 6].binary_search(&4).ok(), Some(1));
assert_eq!([2, 4, 6].binary_search(&6).ok(), Some(2));
assert_eq!([2, 4].binary_search(&1).ok(), None);
assert_eq!([2, 4].binary_search(&5).ok(), None);
assert_eq!([2, 4].binary_search(&2).ok(), Some(0));
assert_eq!([2, 4].binary_search(&4).ok(), Some(1));
assert_eq!([2].binary_search(&1).ok(), None);
assert_eq!([2].binary_search(&5).ok(), None);
assert_eq!([2].binary_search(&2).ok(), Some(0));
assert_eq!([].binary_search(&1).ok(), None);
assert_eq!([].binary_search(&5).ok(), None);
assert!([1, 1, 1, 1, 1].binary_search(&1).ok() != None);
assert!([1, 1, 1, 1, 2].binary_search(&1).ok() != None);
assert!([1, 1, 1, 2, 2].binary_search(&1).ok() != None);
assert!([1, 1, 2, 2, 2].binary_search(&1).ok() != None);
assert_eq!([1, 2, 2, 2, 2].binary_search(&1).ok(), Some(0));
assert_eq!([1, 2, 3, 4, 5].binary_search(&6).ok(), None);
assert_eq!([1, 2, 3, 4, 5].binary_search(&0).ok(), None);
}
#[test]
fn test_reverse() {
let mut v = vec![10, 20];
assert_eq!(v[0], 10);
assert_eq!(v[1], 20);
v.reverse();
assert_eq!(v[0], 20);
assert_eq!(v[1], 10);
let mut v3 = Vec::<i32>::new();
v3.reverse();
assert!(v3.is_empty());
// check the 1-byte-types path
let mut v = (-50..51i8).collect::<Vec<_>>();
v.reverse();
assert_eq!(v, (-50..51i8).rev().collect::<Vec<_>>());
// check the 2-byte-types path
let mut v = (-50..51i16).collect::<Vec<_>>();
v.reverse();
assert_eq!(v, (-50..51i16).rev().collect::<Vec<_>>());
}
#[test]
fn test_sort() {
let mut rng = thread_rng();
for len in (2..25).chain(500..510) {
for &modulus in &[5, 10, 100, 1000] {
for _ in 0..10 {
let orig: Vec<_> = rng.gen_iter::<i32>()
.map(|x| x % modulus)
.take(len)
.collect();
// Sort in default order.
let mut v = orig.clone();
v.sort();
assert!(v.windows(2).all(|w| w[0] <= w[1]));
// Sort in ascending order.
let mut v = orig.clone();
v.sort_by(|a, b| a.cmp(b));
assert!(v.windows(2).all(|w| w[0] <= w[1]));
// Sort in descending order.
let mut v = orig.clone();
v.sort_by(|a, b| b.cmp(a));
assert!(v.windows(2).all(|w| w[0] >= w[1]));
// Sort in lexicographic order.
let mut v1 = orig.clone();
let mut v2 = orig.clone();
v1.sort_by_key(|x| x.to_string());
v2.sort_by_cached_key(|x| x.to_string());
assert!(v1.windows(2).all(|w| w[0].to_string() <= w[1].to_string()));
assert!(v1 == v2);
// Sort with many pre-sorted runs.
let mut v = orig.clone();
v.sort();
v.reverse();
for _ in 0..5 {
let a = rng.gen::<usize>() % len;
let b = rng.gen::<usize>() % len;
if a < b {
v[a..b].reverse();
} else {
v.swap(a, b);
}
}
v.sort();
assert!(v.windows(2).all(|w| w[0] <= w[1]));
}
}
}
// Sort using a completely random comparison function.
// This will reorder the elements *somehow*, but won't panic.
let mut v = [0; 500];
for i in 0..v.len() {
v[i] = i as i32;
}
v.sort_by(|_, _| *rng.choose(&[Less, Equal, Greater]).unwrap());
v.sort();
for i in 0..v.len() {
assert_eq!(v[i], i as i32);
}
// Should not panic.
[0i32; 0].sort();
[(); 10].sort();
[(); 100].sort();
let mut v = [0xDEADBEEFu64];
v.sort();
assert!(v == [0xDEADBEEF]);
}
#[test]
fn test_sort_stability() {
for len in (2..25).chain(500..510) {
for _ in 0..10 {
let mut counts = [0; 10];
// create a vector like [(6, 1), (5, 1), (6, 2), ...],
// where the first item of each tuple is random, but
// the second item represents which occurrence of that
// number this element is, i.e. the second elements
// will occur in sorted order.
let mut orig: Vec<_> = (0..len)
.map(|_| {
let n = thread_rng().gen::<usize>() % 10;
counts[n] += 1;
(n, counts[n])
})
.collect();
let mut v = orig.clone();
// Only sort on the first element, so an unstable sort
// may mix up the counts.
v.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
// This comparison includes the count (the second item
// of the tuple), so elements with equal first items
// will need to be ordered with increasing
// counts... i.e. exactly asserting that this sort is
// stable.
assert!(v.windows(2).all(|w| w[0] <= w[1]));
let mut v = orig.clone();
v.sort_by_cached_key(|&(x, _)| x);
assert!(v.windows(2).all(|w| w[0] <= w[1]));
}
}
}
#[test]
fn test_rotate_left() {
let expected: Vec<_> = (0..13).collect();
let mut v = Vec::new();
// no-ops
v.clone_from(&expected);
v.rotate_left(0);
assert_eq!(v, expected);
v.rotate_left(expected.len());
assert_eq!(v, expected);
let mut zst_array = [(), (), ()];
zst_array.rotate_left(2);
// happy path
v = (5..13).chain(0..5).collect();
v.rotate_left(8);
assert_eq!(v, expected);
let expected: Vec<_> = (0..1000).collect();
// small rotations in large slice, uses ptr::copy
v = (2..1000).chain(0..2).collect();
v.rotate_left(998);
assert_eq!(v, expected);
v = (998..1000).chain(0..998).collect();
v.rotate_left(2);
assert_eq!(v, expected);
// non-small prime rotation, has a few rounds of swapping
v = (389..1000).chain(0..389).collect();
v.rotate_left(1000-389);
assert_eq!(v, expected);
}
#[test]
fn test_rotate_right() {
let expected: Vec<_> = (0..13).collect();
let mut v = Vec::new();
// no-ops
v.clone_from(&expected);
v.rotate_right(0);
assert_eq!(v, expected);
v.rotate_right(expected.len());
assert_eq!(v, expected);
let mut zst_array = [(), (), ()];
zst_array.rotate_right(2);
// happy path
v = (5..13).chain(0..5).collect();
v.rotate_right(5);
assert_eq!(v, expected);
let expected: Vec<_> = (0..1000).collect();
// small rotations in large slice, uses ptr::copy
v = (2..1000).chain(0..2).collect();
v.rotate_right(2);
assert_eq!(v, expected);
v = (998..1000).chain(0..998).collect();
v.rotate_right(998);
assert_eq!(v, expected);
// non-small prime rotation, has a few rounds of swapping
v = (389..1000).chain(0..389).collect();
v.rotate_right(389);
assert_eq!(v, expected);
}
#[test]
fn test_concat() {
let v: [Vec<i32>; 0] = [];
let c = v.concat();
assert_eq!(c, []);
let d = [vec![1], vec![2, 3]].concat();
assert_eq!(d, [1, 2, 3]);
let v: &[&[_]] = &[&[1], &[2, 3]];
assert_eq!(v.join(&0), [1, 0, 2, 3]);
let v: &[&[_]] = &[&[1], &[2], &[3]];
assert_eq!(v.join(&0), [1, 0, 2, 0, 3]);
}
#[test]
fn test_join() {
let v: [Vec<i32>; 0] = [];
assert_eq!(v.join(&0), []);
assert_eq!([vec![1], vec![2, 3]].join(&0), [1, 0, 2, 3]);
assert_eq!([vec![1], vec![2], vec![3]].join(&0), [1, 0, 2, 0, 3]);
let v: [&[_]; 2] = [&[1], &[2, 3]];
assert_eq!(v.join(&0), [1, 0, 2, 3]);
let v: [&[_]; 3] = [&[1], &[2], &[3]];
assert_eq!(v.join(&0), [1, 0, 2, 0, 3]);
}
#[test]
fn test_insert() {
let mut a = vec![1, 2, 4];
a.insert(2, 3);
assert_eq!(a, [1, 2, 3, 4]);
let mut a = vec![1, 2, 3];
a.insert(0, 0);
assert_eq!(a, [0, 1, 2, 3]);
let mut a = vec![1, 2, 3];
a.insert(3, 4);
assert_eq!(a, [1, 2, 3, 4]);
let mut a = vec![];
a.insert(0, 1);
assert_eq!(a, [1]);
}
#[test]
#[should_panic]
fn test_insert_oob() {
let mut a = vec![1, 2, 3];
a.insert(4, 5);
}
#[test]
fn test_remove() {
let mut a = vec![1, 2, 3, 4];
assert_eq!(a.remove(2), 3);
assert_eq!(a, [1, 2, 4]);
assert_eq!(a.remove(2), 4);
assert_eq!(a, [1, 2]);
assert_eq!(a.remove(0), 1);
assert_eq!(a, [2]);
assert_eq!(a.remove(0), 2);
assert_eq!(a, []);
}
#[test]
#[should_panic]
fn test_remove_fail() {
let mut a = vec![1];
let _ = a.remove(0);
let _ = a.remove(0);
}
#[test]
fn test_capacity() {
let mut v = vec![0];
v.reserve_exact(10);
assert!(v.capacity() >= 11);
}
#[test]
fn test_slice_2() {
let v = vec![1, 2, 3, 4, 5];
let v = &v[1..3];
assert_eq!(v.len(), 2);
assert_eq!(v[0], 2);
assert_eq!(v[1], 3);
}
macro_rules! assert_order {
(Greater, $a:expr, $b:expr) => {
assert_eq!($a.cmp($b), Greater);
assert!($a > $b);
};
(Less, $a:expr, $b:expr) => {
assert_eq!($a.cmp($b), Less);
assert!($a < $b);
};
(Equal, $a:expr, $b:expr) => {
assert_eq!($a.cmp($b), Equal);
assert_eq!($a, $b);
}
}
#[test]
fn test_total_ord_u8() {
let c = &[1u8, 2, 3];
assert_order!(Greater, &[1u8, 2, 3, 4][..], &c[..]);
let c = &[1u8, 2, 3, 4];
assert_order!(Less, &[1u8, 2, 3][..], &c[..]);
let c = &[1u8, 2, 3, 6];
assert_order!(Equal, &[1u8, 2, 3, 6][..], &c[..]);
let c = &[1u8, 2, 3, 4, 5, 6];
assert_order!(Less, &[1u8, 2, 3, 4, 5, 5, 5, 5][..], &c[..]);
let c = &[1u8, 2, 3, 4];
assert_order!(Greater, &[2u8, 2][..], &c[..]);
}
#[test]
fn test_total_ord_i32() {
let c = &[1, 2, 3];
assert_order!(Greater, &[1, 2, 3, 4][..], &c[..]);
let c = &[1, 2, 3, 4];
assert_order!(Less, &[1, 2, 3][..], &c[..]);
let c = &[1, 2, 3, 6];
assert_order!(Equal, &[1, 2, 3, 6][..], &c[..]);
let c = &[1, 2, 3, 4, 5, 6];
assert_order!(Less, &[1, 2, 3, 4, 5, 5, 5, 5][..], &c[..]);
let c = &[1, 2, 3, 4];
assert_order!(Greater, &[2, 2][..], &c[..]);
}
#[test]
fn test_iterator() {
let xs = [1, 2, 5, 10, 11];
let mut it = xs.iter();
assert_eq!(it.size_hint(), (5, Some(5)));
assert_eq!(it.next().unwrap(), &1);
assert_eq!(it.size_hint(), (4, Some(4)));
assert_eq!(it.next().unwrap(), &2);
assert_eq!(it.size_hint(), (3, Some(3)));
assert_eq!(it.next().unwrap(), &5);
assert_eq!(it.size_hint(), (2, Some(2)));
assert_eq!(it.next().unwrap(), &10);
assert_eq!(it.size_hint(), (1, Some(1)));
assert_eq!(it.next().unwrap(), &11);
assert_eq!(it.size_hint(), (0, Some(0)));
assert!(it.next().is_none());
}
#[test]
fn test_iter_size_hints() {
let mut xs = [1, 2, 5, 10, 11];
assert_eq!(xs.iter().size_hint(), (5, Some(5)));
assert_eq!(xs.iter_mut().size_hint(), (5, Some(5)));
}
#[test]
fn test_iter_as_slice() {
let xs = [1, 2, 5, 10, 11];
let mut iter = xs.iter();
assert_eq!(iter.as_slice(), &[1, 2, 5, 10, 11]);
iter.next();
assert_eq!(iter.as_slice(), &[2, 5, 10, 11]);
}
#[test]
fn test_iter_as_ref() {
let xs = [1, 2, 5, 10, 11];
let mut iter = xs.iter();
assert_eq!(iter.as_ref(), &[1, 2, 5, 10, 11]);
iter.next();
assert_eq!(iter.as_ref(), &[2, 5, 10, 11]);
}
#[test]
fn test_iter_clone() {
let xs = [1, 2, 5];
let mut it = xs.iter();
it.next();
let mut jt = it.clone();
assert_eq!(it.next(), jt.next());
assert_eq!(it.next(), jt.next());
assert_eq!(it.next(), jt.next());
}
#[test]
fn test_iter_is_empty() {
let xs = [1, 2, 5, 10, 11];
for i in 0..xs.len() {
for j in i..xs.len() {
assert_eq!(xs[i..j].iter().is_empty(), xs[i..j].is_empty());
}
}
}
#[test]
fn test_mut_iterator() {
let mut xs = [1, 2, 3, 4, 5];
for x in &mut xs {
*x += 1;
}
assert!(xs == [2, 3, 4, 5, 6])
}
#[test]
fn test_rev_iterator() {
let xs = [1, 2, 5, 10, 11];
let ys = [11, 10, 5, 2, 1];
let mut i = 0;
for &x in xs.iter().rev() {
assert_eq!(x, ys[i]);
i += 1;
}
assert_eq!(i, 5);
}
#[test]
fn test_mut_rev_iterator() {
let mut xs = [1, 2, 3, 4, 5];
for (i, x) in xs.iter_mut().rev().enumerate() {
*x += i;
}
assert!(xs == [5, 5, 5, 5, 5])
}
#[test]
fn test_move_iterator() {
let xs = vec![1, 2, 3, 4, 5];
assert_eq!(xs.into_iter().fold(0, |a: usize, b: usize| 10 * a + b),
12345);
}
#[test]
fn test_move_rev_iterator() {
let xs = vec![1, 2, 3, 4, 5];
assert_eq!(xs.into_iter().rev().fold(0, |a: usize, b: usize| 10 * a + b),
54321);
}
#[test]
fn test_splitator() {
let xs = &[1, 2, 3, 4, 5];
let splits: &[&[_]] = &[&[1], &[3], &[5]];
assert_eq!(xs.split(|x| *x % 2 == 0).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[], &[2, 3, 4, 5]];
assert_eq!(xs.split(|x| *x == 1).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[1, 2, 3, 4], &[]];
assert_eq!(xs.split(|x| *x == 5).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
assert_eq!(xs.split(|x| *x == 10).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[], &[], &[], &[], &[], &[]];
assert_eq!(xs.split(|_| true).collect::<Vec<&[i32]>>(), splits);
let xs: &[i32] = &[];
let splits: &[&[i32]] = &[&[]];
assert_eq!(xs.split(|x| *x == 5).collect::<Vec<&[i32]>>(), splits);
}
#[test]
fn test_splitnator() {
let xs = &[1, 2, 3, 4, 5];
let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
assert_eq!(xs.splitn(1, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[1], &[3, 4, 5]];
assert_eq!(xs.splitn(2, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[], &[], &[], &[4, 5]];
assert_eq!(xs.splitn(4, |_| true).collect::<Vec<_>>(), splits);
let xs: &[i32] = &[];
let splits: &[&[i32]] = &[&[]];
assert_eq!(xs.splitn(2, |x| *x == 5).collect::<Vec<_>>(), splits);
}
#[test]
fn test_splitnator_mut() {
let xs = &mut [1, 2, 3, 4, 5];
let splits: &[&mut [_]] = &[&mut [1, 2, 3, 4, 5]];
assert_eq!(xs.splitn_mut(1, |x| *x % 2 == 0).collect::<Vec<_>>(),
splits);
let splits: &[&mut [_]] = &[&mut [1], &mut [3, 4, 5]];
assert_eq!(xs.splitn_mut(2, |x| *x % 2 == 0).collect::<Vec<_>>(),
splits);
let splits: &[&mut [_]] = &[&mut [], &mut [], &mut [], &mut [4, 5]];
assert_eq!(xs.splitn_mut(4, |_| true).collect::<Vec<_>>(), splits);
let xs: &mut [i32] = &mut [];
let splits: &[&mut [i32]] = &[&mut []];
assert_eq!(xs.splitn_mut(2, |x| *x == 5).collect::<Vec<_>>(), splits);
}
#[test]
fn test_rsplitator() {
let xs = &[1, 2, 3, 4, 5];
let splits: &[&[_]] = &[&[5], &[3], &[1]];
assert_eq!(xs.split(|x| *x % 2 == 0).rev().collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[2, 3, 4, 5], &[]];
assert_eq!(xs.split(|x| *x == 1).rev().collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[], &[1, 2, 3, 4]];
assert_eq!(xs.split(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
assert_eq!(xs.split(|x| *x == 10).rev().collect::<Vec<_>>(), splits);
let xs: &[i32] = &[];
let splits: &[&[i32]] = &[&[]];
assert_eq!(xs.split(|x| *x == 5).rev().collect::<Vec<&[i32]>>(), splits);
}
#[test]
fn test_rsplitnator() {
let xs = &[1, 2, 3, 4, 5];
let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
assert_eq!(xs.rsplitn(1, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[5], &[1, 2, 3]];
assert_eq!(xs.rsplitn(2, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
let splits: &[&[_]] = &[&[], &[], &[], &[1, 2]];
assert_eq!(xs.rsplitn(4, |_| true).collect::<Vec<_>>(), splits);
let xs: &[i32] = &[];
let splits: &[&[i32]] = &[&[]];
assert_eq!(xs.rsplitn(2, |x| *x == 5).collect::<Vec<&[i32]>>(), splits);
assert!(xs.rsplitn(0, |x| *x % 2 == 0).next().is_none());
}
#[test]
fn test_windowsator() {
let v = &[1, 2, 3, 4];
let wins: &[&[_]] = &[&[1, 2], &[2, 3], &[3, 4]];
assert_eq!(v.windows(2).collect::<Vec<_>>(), wins);
let wins: &[&[_]] = &[&[1, 2, 3], &[2, 3, 4]];
assert_eq!(v.windows(3).collect::<Vec<_>>(), wins);
assert!(v.windows(6).next().is_none());
let wins: &[&[_]] = &[&[3, 4], &[2, 3], &[1, 2]];
assert_eq!(v.windows(2).rev().collect::<Vec<&[_]>>(), wins);
}
#[test]
#[should_panic]
fn test_windowsator_0() {
let v = &[1, 2, 3, 4];
let _it = v.windows(0);
}
#[test]
fn test_chunksator() {
let v = &[1, 2, 3, 4, 5];
assert_eq!(v.chunks(2).len(), 3);
let chunks: &[&[_]] = &[&[1, 2], &[3, 4], &[5]];
assert_eq!(v.chunks(2).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[&[1, 2, 3], &[4, 5]];
assert_eq!(v.chunks(3).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[&[1, 2, 3, 4, 5]];
assert_eq!(v.chunks(6).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[&[5], &[3, 4], &[1, 2]];
assert_eq!(v.chunks(2).rev().collect::<Vec<_>>(), chunks);
}
#[test]
#[should_panic]
fn test_chunksator_0() {
let v = &[1, 2, 3, 4];
let _it = v.chunks(0);
}
#[test]
fn test_exact_chunksator() {
let v = &[1, 2, 3, 4, 5];
assert_eq!(v.exact_chunks(2).len(), 2);
let chunks: &[&[_]] = &[&[1, 2], &[3, 4]];
assert_eq!(v.exact_chunks(2).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[&[1, 2, 3]];
assert_eq!(v.exact_chunks(3).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[];
assert_eq!(v.exact_chunks(6).collect::<Vec<_>>(), chunks);
let chunks: &[&[_]] = &[&[3, 4], &[1, 2]];
assert_eq!(v.exact_chunks(2).rev().collect::<Vec<_>>(), chunks);
}
#[test]
#[should_panic]
fn test_exact_chunksator_0() {
let v = &[1, 2, 3, 4];
let _it = v.exact_chunks(0);
}
#[test]
fn test_reverse_part() {
let mut values = [1, 2, 3, 4, 5];
values[1..4].reverse();
assert!(values == [1, 4, 3, 2, 5]);
}
#[test]
fn test_show() {
macro_rules! test_show_vec {
($x:expr, $x_str:expr) => ({
let (x, x_str) = ($x, $x_str);
assert_eq!(format!("{:?}", x), x_str);
assert_eq!(format!("{:?}", x), x_str);
})
}
let empty = Vec::<i32>::new();
test_show_vec!(empty, "[]");
test_show_vec!(vec![1], "[1]");
test_show_vec!(vec![1, 2, 3], "[1, 2, 3]");
test_show_vec!(vec![vec![], vec![1], vec![1, 1]], "[[], [1], [1, 1]]");
let empty_mut: &mut [i32] = &mut [];
test_show_vec!(empty_mut, "[]");
let v = &mut [1];
test_show_vec!(v, "[1]");
let v = &mut [1, 2, 3];
test_show_vec!(v, "[1, 2, 3]");
let v: &mut [&mut [_]] = &mut [&mut [], &mut [1], &mut [1, 1]];
test_show_vec!(v, "[[], [1], [1, 1]]");
}
#[test]
fn test_vec_default() {
macro_rules! t {
($ty:ty) => {{
let v: $ty = Default::default();
assert!(v.is_empty());
}}
}
t!(&[i32]);
t!(Vec<i32>);
}
#[test]
#[should_panic]
fn test_overflow_does_not_cause_segfault() {
let mut v = vec![];
v.reserve_exact(!0);
v.push(1);
v.push(2);
}
#[test]
#[should_panic]
fn test_overflow_does_not_cause_segfault_managed() {
let mut v = vec![Rc::new(1)];
v.reserve_exact(!0);
v.push(Rc::new(2));
}
#[test]
fn test_mut_split_at() {
let mut values = [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!(values == [2, 3, 5, 6, 7]);
}
#[derive(Clone, PartialEq)]
struct Foo;
#[test]
fn test_iter_zero_sized() {
let mut v = vec![Foo, Foo, Foo];
assert_eq!(v.len(), 3);
let mut cnt = 0;
for f in &v {
assert!(*f == Foo);
cnt += 1;
}
assert_eq!(cnt, 3);
for f in &v[1..3] {
assert!(*f == Foo);
cnt += 1;
}
assert_eq!(cnt, 5);
for f in &mut v {
assert!(*f == Foo);
cnt += 1;
}
assert_eq!(cnt, 8);
for f in v {
assert!(f == Foo);
cnt += 1;
}
assert_eq!(cnt, 11);
let xs: [Foo; 3] = [Foo, Foo, Foo];
cnt = 0;
for f in &xs {
assert!(*f == Foo);
cnt += 1;
}
assert!(cnt == 3);
}
#[test]
fn test_shrink_to_fit() {
let mut xs = vec![0, 1, 2, 3];
for i in 4..100 {
xs.push(i)
}
assert_eq!(xs.capacity(), 128);
xs.shrink_to_fit();
assert_eq!(xs.capacity(), 100);
assert_eq!(xs, (0..100).collect::<Vec<_>>());
}
#[test]
fn test_starts_with() {
assert!(b"foobar".starts_with(b"foo"));
assert!(!b"foobar".starts_with(b"oob"));
assert!(!b"foobar".starts_with(b"bar"));
assert!(!b"foo".starts_with(b"foobar"));
assert!(!b"bar".starts_with(b"foobar"));
assert!(b"foobar".starts_with(b"foobar"));
let empty: &[u8] = &[];
assert!(empty.starts_with(empty));
assert!(!empty.starts_with(b"foo"));
assert!(b"foobar".starts_with(empty));
}
#[test]
fn test_ends_with() {
assert!(b"foobar".ends_with(b"bar"));
assert!(!b"foobar".ends_with(b"oba"));
assert!(!b"foobar".ends_with(b"foo"));
assert!(!b"foo".ends_with(b"foobar"));
assert!(!b"bar".ends_with(b"foobar"));
assert!(b"foobar".ends_with(b"foobar"));
let empty: &[u8] = &[];
assert!(empty.ends_with(empty));
assert!(!empty.ends_with(b"foo"));
assert!(b"foobar".ends_with(empty));
}
#[test]
fn test_mut_splitator() {
let mut xs = [0, 1, 0, 2, 3, 0, 0, 4, 5, 0];
assert_eq!(xs.split_mut(|x| *x == 0).count(), 6);
for slice in xs.split_mut(|x| *x == 0) {
slice.reverse();
}
assert!(xs == [0, 1, 0, 3, 2, 0, 0, 5, 4, 0]);
let mut xs = [0, 1, 0, 2, 3, 0, 0, 4, 5, 0, 6, 7];
for slice in xs.split_mut(|x| *x == 0).take(5) {
slice.reverse();
}
assert!(xs == [0, 1, 0, 3, 2, 0, 0, 5, 4, 0, 6, 7]);
}
#[test]
fn test_mut_splitator_rev() {
let mut xs = [1, 2, 0, 3, 4, 0, 0, 5, 6, 0];
for slice in xs.split_mut(|x| *x == 0).rev().take(4) {
slice.reverse();
}
assert!(xs == [1, 2, 0, 4, 3, 0, 0, 6, 5, 0]);
}
#[test]
fn test_get_mut() {
let mut v = [0, 1, 2];
assert_eq!(v.get_mut(3), None);
v.get_mut(1).map(|e| *e = 7);
assert_eq!(v[1], 7);
let mut x = 2;
assert_eq!(v.get_mut(2), Some(&mut x));
}
#[test]
fn test_mut_chunks() {
let mut v = [0, 1, 2, 3, 4, 5, 6];
assert_eq!(v.chunks_mut(2).len(), 4);
for (i, chunk) in v.chunks_mut(3).enumerate() {
for x in chunk {
*x = i as u8;
}
}
let result = [0, 0, 0, 1, 1, 1, 2];
assert_eq!(v, result);
}
#[test]
fn test_mut_chunks_rev() {
let mut v = [0, 1, 2, 3, 4, 5, 6];
for (i, chunk) in v.chunks_mut(3).rev().enumerate() {
for x in chunk {
*x = i as u8;
}
}
let result = [2, 2, 2, 1, 1, 1, 0];
assert_eq!(v, result);
}
#[test]
#[should_panic]
fn test_mut_chunks_0() {
let mut v = [1, 2, 3, 4];
let _it = v.chunks_mut(0);
}
#[test]
fn test_mut_exact_chunks() {
let mut v = [0, 1, 2, 3, 4, 5, 6];
assert_eq!(v.exact_chunks_mut(2).len(), 3);
for (i, chunk) in v.exact_chunks_mut(3).enumerate() {
for x in chunk {
*x = i as u8;
}
}
let result = [0, 0, 0, 1, 1, 1, 6];
assert_eq!(v, result);
}
#[test]
fn test_mut_exact_chunks_rev() {
let mut v = [0, 1, 2, 3, 4, 5, 6];
for (i, chunk) in v.exact_chunks_mut(3).rev().enumerate() {
for x in chunk {
*x = i as u8;
}
}
let result = [1, 1, 1, 0, 0, 0, 6];
assert_eq!(v, result);
}
#[test]
#[should_panic]
fn test_mut_exact_chunks_0() {
let mut v = [1, 2, 3, 4];
let _it = v.exact_chunks_mut(0);
}
#[test]
fn test_mut_last() {
let mut x = [1, 2, 3, 4, 5];
let h = x.last_mut();
assert_eq!(*h.unwrap(), 5);
let y: &mut [i32] = &mut [];
assert!(y.last_mut().is_none());
}
#[test]
fn test_to_vec() {
let xs: Box<_> = box [1, 2, 3];
let ys = xs.to_vec();
assert_eq!(ys, [1, 2, 3]);
}
#[test]
fn test_box_slice_clone() {
let data = vec![vec![0, 1], vec![0], vec![1]];
let data2 = data.clone().into_boxed_slice().clone().to_vec();
assert_eq!(data, data2);
}
#[test]
#[cfg_attr(target_os = "emscripten", ignore)]
fn test_box_slice_clone_panics() {
use std::sync::Arc;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::thread::spawn;
struct Canary {
count: Arc<AtomicUsize>,
panics: bool,
}
impl Drop for Canary {
fn drop(&mut self) {
self.count.fetch_add(1, Ordering::SeqCst);
}
}
impl Clone for Canary {
fn clone(&self) -> Self {
if self.panics {
panic!()
}
Canary {
count: self.count.clone(),
panics: self.panics,
}
}
}
let drop_count = Arc::new(AtomicUsize::new(0));
let canary = Canary {
count: drop_count.clone(),
panics: false,
};
let panic = Canary {
count: drop_count.clone(),
panics: true,
};
spawn(move || {
// When xs is dropped, +5.
let xs = vec![canary.clone(), canary.clone(), canary.clone(), panic, canary]
.into_boxed_slice();
// When panic is cloned, +3.
xs.clone();
})
.join()
.unwrap_err();
// Total = 8
assert_eq!(drop_count.load(Ordering::SeqCst), 8);
}
#[test]
fn test_copy_from_slice() {
let src = [0, 1, 2, 3, 4, 5];
let mut dst = [0; 6];
dst.copy_from_slice(&src);
assert_eq!(src, dst)
}
#[test]
#[should_panic(expected = "destination and source slices have different lengths")]
fn test_copy_from_slice_dst_longer() {
let src = [0, 1, 2, 3];
let mut dst = [0; 5];
dst.copy_from_slice(&src);
}
#[test]
#[should_panic(expected = "destination and source slices have different lengths")]
fn test_copy_from_slice_dst_shorter() {
let src = [0, 1, 2, 3];
let mut dst = [0; 3];
dst.copy_from_slice(&src);
}
const MAX_LEN: usize = 80;
static DROP_COUNTS: [AtomicUsize; MAX_LEN] = [
// FIXME(RFC 1109): AtomicUsize is not Copy.
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
];
static VERSIONS: AtomicUsize = ATOMIC_USIZE_INIT;
#[derive(Clone, Eq)]
struct DropCounter {
x: u32,
id: usize,
version: Cell<usize>,
}
impl PartialEq for DropCounter {
fn eq(&self, other: &Self) -> bool {
self.partial_cmp(other) == Some(Ordering::Equal)
}
}
impl PartialOrd for DropCounter {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.version.set(self.version.get() + 1);
other.version.set(other.version.get() + 1);
VERSIONS.fetch_add(2, Relaxed);
self.x.partial_cmp(&other.x)
}
}
impl Ord for DropCounter {
fn cmp(&self, other: &Self) -> Ordering {
self.partial_cmp(other).unwrap()
}
}
impl Drop for DropCounter {
fn drop(&mut self) {
DROP_COUNTS[self.id].fetch_add(1, Relaxed);
VERSIONS.fetch_sub(self.version.get(), Relaxed);
}
}
macro_rules! test {
($input:ident, $func:ident) => {
let len = $input.len();
// Work out the total number of comparisons required to sort
// this array...
let mut count = 0usize;
$input.to_owned().$func(|a, b| { count += 1; a.cmp(b) });
// ... and then panic on each and every single one.
for panic_countdown in 0..count {
// Refresh the counters.
VERSIONS.store(0, Relaxed);
for i in 0..len {
DROP_COUNTS[i].store(0, Relaxed);
}
let v = $input.to_owned();
let _ = thread::spawn(move || {
let mut v = v;
let mut panic_countdown = panic_countdown;
v.$func(|a, b| {
if panic_countdown == 0 {
SILENCE_PANIC.with(|s| s.set(true));
panic!();
}
panic_countdown -= 1;
a.cmp(b)
})
}).join();
// Check that the number of things dropped is exactly
// what we expect (i.e. the contents of `v`).
for (i, c) in DROP_COUNTS.iter().enumerate().take(len) {
let count = c.load(Relaxed);
assert!(count == 1,
"found drop count == {} for i == {}, len == {}",
count, i, len);
}
// Check that the most recent versions of values were dropped.
assert_eq!(VERSIONS.load(Relaxed), 0);
}
}
}
thread_local!(static SILENCE_PANIC: Cell<bool> = Cell::new(false));
#[test]
#[cfg_attr(target_os = "emscripten", ignore)] // no threads
fn panic_safe() {
let prev = panic::take_hook();
panic::set_hook(Box::new(move |info| {
if !SILENCE_PANIC.with(|s| s.get()) {
prev(info);
}
}));
let mut rng = thread_rng();
for len in (1..20).chain(70..MAX_LEN) {
for &modulus in &[5, 20, 50] {
for &has_runs in &[false, true] {
let mut input = (0..len)
.map(|id| {
DropCounter {
x: rng.next_u32() % modulus,
id: id,
version: Cell::new(0),
}
})
.collect::<Vec<_>>();
if has_runs {
for c in &mut input {
c.x = c.id as u32;
}
for _ in 0..5 {
let a = rng.gen::<usize>() % len;
let b = rng.gen::<usize>() % len;
if a < b {
input[a..b].reverse();
} else {
input.swap(a, b);
}
}
}
test!(input, sort_by);
test!(input, sort_unstable_by);
}
}
}
}
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