rust/library/core/tests/slice.rs
bors 547f2ba06b Auto merge of #86988 - thomcc:chunky-splitz-says-no-checking, r=the8472
Carefully remove bounds checks from some chunk iterator functions

So, I was writing code that requires the equivalent of `rchunks(N).rev()` (which isn't the same as forward `chunks(N)` — in particular, if the buffer length is not a multiple of `N`, I must handle the "remainder" first).

I happened to look at the codegen output of the function (I was actually interested in whether or not a nested loop was being unrolled — it was), and noticed that in the outer `rchunks(n).rev()` loop, LLVM seemed to be unable to remove the bounds checks from the iteration: https://rust.godbolt.org/z/Tnz4MYY8f (this panic was from the split_at in `RChunks::next_back`).

After doing some experimentation, it seems all of the `next_back` in the non-exact chunk iterators have the issue: (`Chunks::next_back`, `RChunks::next_back`, `ChunksMut::next_back`, and `RChunksMut::next_back`)...

Even worse, the forward `rchunks` iterators sometimes have the issue as well (... but only sometimes). For example https://rust.godbolt.org/z/oGhbqv53r has bounds checks, but if I uncomment the loop body, it manages to remove the check (which is bizarre, since I'd expect the opposite...). I suspect it's highly dependent on the surrounding code, so I decided to remove the bounds checks from them anyway. Overall, this change includes:
- All `next_back` functions on the non-`Exact` iterators (e.g. `R?Chunks(Mut)?`).
- All `next` functions on the non-exact rchunks iterators (e.g. `RChunks(Mut)?`).

I wasn't able to catch any of the other chunk iterators failing to remove the bounds checks (I checked iterations over `r?chunks(_exact)?(_mut)?` with constant chunk sizes under `-O3`, `-Os`, and `-Oz`), which makes sense, since these were the cases where it was harder to prove the bounds check correct to remove...

In fact, it took quite a bit of thinking to convince myself that using unchecked_ here was valid — so I'm not really surprised that LLVM had trouble (although compilers are slightly better at this sort of reasoning than humans). A consequence of that is the fact that the `// SAFETY` comment for these are... kinda long...

---

I didn't do this for, or even think about it for, any of the other iteration methods; just `next` and `next_back` (where it mattered). If this PR is accepted, I'll file a follow up for someone (possibly me) to look at the others later (in particular, `nth`/`nth_back` looked like they had similar logic), but I wanted to do this now, as IMO `next`/`next_back` are the most important here, since they're what gets used by the iteration protocol.

---

Note: While I don't expect this to impact performance directly, the panic is a side effect, which would otherwise not exist in these loops. That is, this could prevent the compiler from being able to move/remove/otherwise rework a loop over these iterators (as an example, it could not delete the code for a loop whose body computes a value which doesn't get used).

Also, some like to be able to have confidence this code has no panicking branches in the optimized code, and "no bounds checks" is kinda part of the selling point of Rust's iterators anyway.
2022-02-01 10:11:59 +00:00

2483 lines
69 KiB
Rust

use core::cell::Cell;
use core::cmp::Ordering;
use core::mem::MaybeUninit;
use core::result::Result::{Err, Ok};
#[test]
fn test_position() {
let b = [1, 2, 3, 5, 5];
assert_eq!(b.iter().position(|&v| v == 9), None);
assert_eq!(b.iter().position(|&v| v == 5), Some(3));
assert_eq!(b.iter().position(|&v| v == 3), Some(2));
assert_eq!(b.iter().position(|&v| v == 0), None);
}
#[test]
fn test_rposition() {
let b = [1, 2, 3, 5, 5];
assert_eq!(b.iter().rposition(|&v| v == 9), None);
assert_eq!(b.iter().rposition(|&v| v == 5), Some(4));
assert_eq!(b.iter().rposition(|&v| v == 3), Some(2));
assert_eq!(b.iter().rposition(|&v| v == 0), None);
}
#[test]
fn test_binary_search() {
let b: [i32; 0] = [];
assert_eq!(b.binary_search(&5), Err(0));
let b = [4];
assert_eq!(b.binary_search(&3), Err(0));
assert_eq!(b.binary_search(&4), Ok(0));
assert_eq!(b.binary_search(&5), Err(1));
let b = [1, 2, 4, 6, 8, 9];
assert_eq!(b.binary_search(&5), Err(3));
assert_eq!(b.binary_search(&6), Ok(3));
assert_eq!(b.binary_search(&7), Err(4));
assert_eq!(b.binary_search(&8), Ok(4));
let b = [1, 2, 4, 5, 6, 8];
assert_eq!(b.binary_search(&9), Err(6));
let b = [1, 2, 4, 6, 7, 8, 9];
assert_eq!(b.binary_search(&6), Ok(3));
assert_eq!(b.binary_search(&5), Err(3));
assert_eq!(b.binary_search(&8), Ok(5));
let b = [1, 2, 4, 5, 6, 8, 9];
assert_eq!(b.binary_search(&7), Err(5));
assert_eq!(b.binary_search(&0), Err(0));
let b = [1, 3, 3, 3, 7];
assert_eq!(b.binary_search(&0), Err(0));
assert_eq!(b.binary_search(&1), Ok(0));
assert_eq!(b.binary_search(&2), Err(1));
assert!(match b.binary_search(&3) {
Ok(1..=3) => true,
_ => false,
});
assert!(match b.binary_search(&3) {
Ok(1..=3) => true,
_ => false,
});
assert_eq!(b.binary_search(&4), Err(4));
assert_eq!(b.binary_search(&5), Err(4));
assert_eq!(b.binary_search(&6), Err(4));
assert_eq!(b.binary_search(&7), Ok(4));
assert_eq!(b.binary_search(&8), Err(5));
let b = [(); usize::MAX];
assert_eq!(b.binary_search(&()), Ok(usize::MAX / 2));
}
#[test]
fn test_binary_search_by_overflow() {
let b = [(); usize::MAX];
assert_eq!(b.binary_search_by(|_| Ordering::Equal), Ok(usize::MAX / 2));
assert_eq!(b.binary_search_by(|_| Ordering::Greater), Err(0));
assert_eq!(b.binary_search_by(|_| Ordering::Less), Err(usize::MAX));
}
#[test]
// Test implementation specific behavior when finding equivalent elements.
// It is ok to break this test but when you do a crater run is highly advisable.
fn test_binary_search_implementation_details() {
let b = [1, 1, 2, 2, 3, 3, 3];
assert_eq!(b.binary_search(&1), Ok(1));
assert_eq!(b.binary_search(&2), Ok(3));
assert_eq!(b.binary_search(&3), Ok(5));
let b = [1, 1, 1, 1, 1, 3, 3, 3, 3];
assert_eq!(b.binary_search(&1), Ok(4));
assert_eq!(b.binary_search(&3), Ok(7));
let b = [1, 1, 1, 1, 3, 3, 3, 3, 3];
assert_eq!(b.binary_search(&1), Ok(2));
assert_eq!(b.binary_search(&3), Ok(4));
}
#[test]
fn test_partition_point() {
let b: [i32; 0] = [];
assert_eq!(b.partition_point(|&x| x < 5), 0);
let b = [4];
assert_eq!(b.partition_point(|&x| x < 3), 0);
assert_eq!(b.partition_point(|&x| x < 4), 0);
assert_eq!(b.partition_point(|&x| x < 5), 1);
let b = [1, 2, 4, 6, 8, 9];
assert_eq!(b.partition_point(|&x| x < 5), 3);
assert_eq!(b.partition_point(|&x| x < 6), 3);
assert_eq!(b.partition_point(|&x| x < 7), 4);
assert_eq!(b.partition_point(|&x| x < 8), 4);
let b = [1, 2, 4, 5, 6, 8];
assert_eq!(b.partition_point(|&x| x < 9), 6);
let b = [1, 2, 4, 6, 7, 8, 9];
assert_eq!(b.partition_point(|&x| x < 6), 3);
assert_eq!(b.partition_point(|&x| x < 5), 3);
assert_eq!(b.partition_point(|&x| x < 8), 5);
let b = [1, 2, 4, 5, 6, 8, 9];
assert_eq!(b.partition_point(|&x| x < 7), 5);
assert_eq!(b.partition_point(|&x| x < 0), 0);
let b = [1, 3, 3, 3, 7];
assert_eq!(b.partition_point(|&x| x < 0), 0);
assert_eq!(b.partition_point(|&x| x < 1), 0);
assert_eq!(b.partition_point(|&x| x < 2), 1);
assert_eq!(b.partition_point(|&x| x < 3), 1);
assert_eq!(b.partition_point(|&x| x < 4), 4);
assert_eq!(b.partition_point(|&x| x < 5), 4);
assert_eq!(b.partition_point(|&x| x < 6), 4);
assert_eq!(b.partition_point(|&x| x < 7), 4);
assert_eq!(b.partition_point(|&x| x < 8), 5);
}
#[test]
fn test_iterator_advance_by() {
let v = &[0, 1, 2, 3, 4];
for i in 0..=v.len() {
let mut iter = v.iter();
iter.advance_by(i).unwrap();
assert_eq!(iter.as_slice(), &v[i..]);
}
let mut iter = v.iter();
assert_eq!(iter.advance_by(v.len() + 1), Err(v.len()));
assert_eq!(iter.as_slice(), &[]);
let mut iter = v.iter();
iter.advance_by(3).unwrap();
assert_eq!(iter.as_slice(), &v[3..]);
iter.advance_by(2).unwrap();
assert_eq!(iter.as_slice(), &[]);
iter.advance_by(0).unwrap();
}
#[test]
fn test_iterator_advance_back_by() {
let v = &[0, 1, 2, 3, 4];
for i in 0..=v.len() {
let mut iter = v.iter();
iter.advance_back_by(i).unwrap();
assert_eq!(iter.as_slice(), &v[..v.len() - i]);
}
let mut iter = v.iter();
assert_eq!(iter.advance_back_by(v.len() + 1), Err(v.len()));
assert_eq!(iter.as_slice(), &[]);
let mut iter = v.iter();
iter.advance_back_by(3).unwrap();
assert_eq!(iter.as_slice(), &v[..v.len() - 3]);
iter.advance_back_by(2).unwrap();
assert_eq!(iter.as_slice(), &[]);
iter.advance_back_by(0).unwrap();
}
#[test]
fn test_iterator_nth() {
let v: &[_] = &[0, 1, 2, 3, 4];
for i in 0..v.len() {
assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
}
assert_eq!(v.iter().nth(v.len()), None);
let mut iter = v.iter();
assert_eq!(iter.nth(2).unwrap(), &v[2]);
assert_eq!(iter.nth(1).unwrap(), &v[4]);
}
#[test]
fn test_iterator_nth_back() {
let v: &[_] = &[0, 1, 2, 3, 4];
for i in 0..v.len() {
assert_eq!(v.iter().nth_back(i).unwrap(), &v[v.len() - i - 1]);
}
assert_eq!(v.iter().nth_back(v.len()), None);
let mut iter = v.iter();
assert_eq!(iter.nth_back(2).unwrap(), &v[2]);
assert_eq!(iter.nth_back(1).unwrap(), &v[0]);
}
#[test]
fn test_iterator_last() {
let v: &[_] = &[0, 1, 2, 3, 4];
assert_eq!(v.iter().last().unwrap(), &4);
assert_eq!(v[..1].iter().last().unwrap(), &0);
}
#[test]
fn test_iterator_count() {
let v: &[_] = &[0, 1, 2, 3, 4];
assert_eq!(v.iter().count(), 5);
let mut iter2 = v.iter();
iter2.next();
iter2.next();
assert_eq!(iter2.count(), 3);
}
#[test]
fn test_chunks_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.chunks(3);
assert_eq!(c.count(), 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.chunks(2);
assert_eq!(c2.count(), 3);
let v3: &[i32] = &[];
let c3 = v3.chunks(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_chunks_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.chunks(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.chunks(3);
assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_chunks_next() {
let v = [0, 1, 2, 3, 4, 5];
let mut c = v.chunks(2);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next().unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
assert_eq!(c.next(), None);
let v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.chunks(3);
assert_eq!(c.next().unwrap(), &[0, 1, 2]);
assert_eq!(c.next().unwrap(), &[3, 4, 5]);
assert_eq!(c.next().unwrap(), &[6, 7]);
assert_eq!(c.next(), None);
}
#[test]
fn test_chunks_next_back() {
let v = [0, 1, 2, 3, 4, 5];
let mut c = v.chunks(2);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
assert_eq!(c.next_back().unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[0, 1]);
assert_eq!(c.next_back(), None);
let v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.chunks(3);
assert_eq!(c.next_back().unwrap(), &[6, 7]);
assert_eq!(c.next_back().unwrap(), &[3, 4, 5]);
assert_eq!(c.next_back().unwrap(), &[0, 1, 2]);
assert_eq!(c.next_back(), None);
}
#[test]
fn test_chunks_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.chunks(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.chunks(3);
assert_eq!(c2.nth_back(1).unwrap(), &[0, 1, 2]);
assert_eq!(c2.next(), None);
assert_eq!(c2.next_back(), None);
let v3: &[i32] = &[0, 1, 2, 3, 4];
let mut c3 = v3.chunks(10);
assert_eq!(c3.nth_back(0).unwrap(), &[0, 1, 2, 3, 4]);
assert_eq!(c3.next(), None);
let v4: &[i32] = &[0, 1, 2];
let mut c4 = v4.chunks(10);
assert_eq!(c4.nth_back(1_000_000_000usize), None);
}
#[test]
fn test_chunks_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.chunks(2);
assert_eq!(c.last().unwrap()[1], 5);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.chunks(2);
assert_eq!(c2.last().unwrap()[0], 4);
}
#[test]
fn test_chunks_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.chunks(2)
.zip(v2.chunks(2))
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, vec![14, 22, 14]);
}
#[test]
fn test_chunks_mut_count() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.chunks_mut(3);
assert_eq!(c.count(), 2);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.chunks_mut(2);
assert_eq!(c2.count(), 3);
let v3: &mut [i32] = &mut [];
let c3 = v3.chunks_mut(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_chunks_mut_nth() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.chunks_mut(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c2 = v2.chunks_mut(3);
assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_chunks_mut_nth_back() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.chunks_mut(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c1 = v1.chunks_mut(3);
assert_eq!(c1.nth_back(1).unwrap(), &[0, 1, 2]);
assert_eq!(c1.next(), None);
let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c3 = v3.chunks_mut(10);
assert_eq!(c3.nth_back(0).unwrap(), &[0, 1, 2, 3, 4]);
assert_eq!(c3.next(), None);
let v4: &mut [i32] = &mut [0, 1, 2];
let mut c4 = v4.chunks_mut(10);
assert_eq!(c4.nth_back(1_000_000_000usize), None);
}
#[test]
fn test_chunks_mut_last() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.chunks_mut(2);
assert_eq!(c.last().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.chunks_mut(2);
assert_eq!(c2.last().unwrap(), &[4]);
}
#[test]
fn test_chunks_mut_zip() {
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
for (a, b) in v1.chunks_mut(2).zip(v2.chunks(2)) {
let sum = b.iter().sum::<i32>();
for v in a {
*v += sum;
}
}
assert_eq!(v1, [13, 14, 19, 20, 14]);
}
#[test]
fn test_chunks_exact_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.chunks_exact(3);
assert_eq!(c.count(), 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.chunks_exact(2);
assert_eq!(c2.count(), 2);
let v3: &[i32] = &[];
let c3 = v3.chunks_exact(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_chunks_exact_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.chunks_exact(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.chunks_exact(3);
assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_chunks_exact_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.chunks_exact(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.chunks_exact(3);
assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
assert_eq!(c2.next(), None);
assert_eq!(c2.next_back(), None);
let v3: &[i32] = &[0, 1, 2, 3, 4];
let mut c3 = v3.chunks_exact(10);
assert_eq!(c3.nth_back(0), None);
}
#[test]
fn test_chunks_exact_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.chunks_exact(2);
assert_eq!(c.last().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.chunks_exact(2);
assert_eq!(c2.last().unwrap(), &[2, 3]);
}
#[test]
fn test_chunks_exact_remainder() {
let v: &[i32] = &[0, 1, 2, 3, 4];
let c = v.chunks_exact(2);
assert_eq!(c.remainder(), &[4]);
}
#[test]
fn test_chunks_exact_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.chunks_exact(2)
.zip(v2.chunks_exact(2))
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, vec![14, 22]);
}
#[test]
fn test_chunks_exact_mut_count() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.chunks_exact_mut(3);
assert_eq!(c.count(), 2);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.chunks_exact_mut(2);
assert_eq!(c2.count(), 2);
let v3: &mut [i32] = &mut [];
let c3 = v3.chunks_exact_mut(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_chunks_exact_mut_nth() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.chunks_exact_mut(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.chunks_exact_mut(3);
assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_chunks_exact_mut_nth_back() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.chunks_exact_mut(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c2 = v2.chunks_exact_mut(3);
assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
assert_eq!(c2.next(), None);
assert_eq!(c2.next_back(), None);
let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c3 = v3.chunks_exact_mut(10);
assert_eq!(c3.nth_back(0), None);
}
#[test]
fn test_chunks_exact_mut_last() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.chunks_exact_mut(2);
assert_eq!(c.last().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.chunks_exact_mut(2);
assert_eq!(c2.last().unwrap(), &[2, 3]);
}
#[test]
fn test_chunks_exact_mut_remainder() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c = v.chunks_exact_mut(2);
assert_eq!(c.into_remainder(), &[4]);
}
#[test]
fn test_chunks_exact_mut_zip() {
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
for (a, b) in v1.chunks_exact_mut(2).zip(v2.chunks_exact(2)) {
let sum = b.iter().sum::<i32>();
for v in a {
*v += sum;
}
}
assert_eq!(v1, [13, 14, 19, 20, 4]);
}
#[test]
fn test_array_chunks_infer() {
let v: &[i32] = &[0, 1, 2, 3, 4, -4];
let c = v.array_chunks();
for &[a, b, c] in c {
assert_eq!(a + b + c, 3);
}
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let total = v2.array_chunks().map(|&[a, b]| a * b).sum::<i32>();
assert_eq!(total, 2 * 3 + 4 * 5);
}
#[test]
fn test_array_chunks_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.array_chunks::<3>();
assert_eq!(c.count(), 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.array_chunks::<2>();
assert_eq!(c2.count(), 2);
let v3: &[i32] = &[];
let c3 = v3.array_chunks::<2>();
assert_eq!(c3.count(), 0);
}
#[test]
fn test_array_chunks_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.array_chunks::<2>();
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.array_chunks::<3>();
assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_array_chunks_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.array_chunks::<2>();
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.array_chunks::<3>();
assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
assert_eq!(c2.next(), None);
assert_eq!(c2.next_back(), None);
let v3: &[i32] = &[0, 1, 2, 3, 4];
let mut c3 = v3.array_chunks::<10>();
assert_eq!(c3.nth_back(0), None);
}
#[test]
fn test_array_chunks_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.array_chunks::<2>();
assert_eq!(c.last().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.array_chunks::<2>();
assert_eq!(c2.last().unwrap(), &[2, 3]);
}
#[test]
fn test_array_chunks_remainder() {
let v: &[i32] = &[0, 1, 2, 3, 4];
let c = v.array_chunks::<2>();
assert_eq!(c.remainder(), &[4]);
}
#[test]
fn test_array_chunks_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.array_chunks::<2>()
.zip(v2.array_chunks::<2>())
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, vec![14, 22]);
}
#[test]
fn test_array_chunks_mut_infer() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
for a in v.array_chunks_mut() {
let sum = a.iter().sum::<i32>();
*a = [sum; 3];
}
assert_eq!(v, &[3, 3, 3, 12, 12, 12, 6]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
v2.array_chunks_mut().for_each(|[a, b]| core::mem::swap(a, b));
assert_eq!(v2, &[1, 0, 3, 2, 5, 4, 6]);
}
#[test]
fn test_array_chunks_mut_count() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.array_chunks_mut::<3>();
assert_eq!(c.count(), 2);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.array_chunks_mut::<2>();
assert_eq!(c2.count(), 2);
let v3: &mut [i32] = &mut [];
let c3 = v3.array_chunks_mut::<2>();
assert_eq!(c3.count(), 0);
}
#[test]
fn test_array_chunks_mut_nth() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.array_chunks_mut::<2>();
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.array_chunks_mut::<3>();
assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_array_chunks_mut_nth_back() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.array_chunks_mut::<2>();
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c2 = v2.array_chunks_mut::<3>();
assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
assert_eq!(c2.next(), None);
assert_eq!(c2.next_back(), None);
let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c3 = v3.array_chunks_mut::<10>();
assert_eq!(c3.nth_back(0), None);
}
#[test]
fn test_array_chunks_mut_last() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.array_chunks_mut::<2>();
assert_eq!(c.last().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.array_chunks_mut::<2>();
assert_eq!(c2.last().unwrap(), &[2, 3]);
}
#[test]
fn test_array_chunks_mut_remainder() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c = v.array_chunks_mut::<2>();
assert_eq!(c.into_remainder(), &[4]);
}
#[test]
fn test_array_chunks_mut_zip() {
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
for (a, b) in v1.array_chunks_mut::<2>().zip(v2.array_chunks::<2>()) {
let sum = b.iter().sum::<i32>();
for v in a {
*v += sum;
}
}
assert_eq!(v1, [13, 14, 19, 20, 4]);
}
#[test]
fn test_array_windows_infer() {
let v: &[i32] = &[0, 1, 0, 1];
assert_eq!(v.array_windows::<2>().count(), 3);
let c = v.array_windows();
for &[a, b] in c {
assert_eq!(a + b, 1);
}
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let total = v2.array_windows().map(|&[a, b, c]| a + b + c).sum::<i32>();
assert_eq!(total, 3 + 6 + 9 + 12 + 15);
}
#[test]
fn test_array_windows_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.array_windows::<3>();
assert_eq!(c.count(), 4);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.array_windows::<6>();
assert_eq!(c2.count(), 0);
let v3: &[i32] = &[];
let c3 = v3.array_windows::<2>();
assert_eq!(c3.count(), 0);
let v4: &[()] = &[(); usize::MAX];
let c4 = v4.array_windows::<1>();
assert_eq!(c4.count(), usize::MAX);
}
#[test]
fn test_array_windows_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let snd = v.array_windows::<4>().nth(1);
assert_eq!(snd, Some(&[1, 2, 3, 4]));
let mut arr_windows = v.array_windows::<2>();
assert_ne!(arr_windows.nth(0), arr_windows.nth(0));
let last = v.array_windows::<3>().last();
assert_eq!(last, Some(&[3, 4, 5]));
}
#[test]
fn test_array_windows_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let snd = v.array_windows::<4>().nth_back(1);
assert_eq!(snd, Some(&[1, 2, 3, 4]));
let mut arr_windows = v.array_windows::<2>();
assert_ne!(arr_windows.nth_back(0), arr_windows.nth_back(0));
}
#[test]
fn test_rchunks_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.rchunks(3);
assert_eq!(c.count(), 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.rchunks(2);
assert_eq!(c2.count(), 3);
let v3: &[i32] = &[];
let c3 = v3.rchunks(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_rchunks_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.rchunks(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.rchunks(3);
assert_eq!(c2.nth(1).unwrap(), &[0, 1]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.rchunks(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.rchunks(3);
assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
assert_eq!(c2.next_back(), None);
}
#[test]
fn test_rchunks_next() {
let v = [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks(2);
assert_eq!(c.next().unwrap(), &[4, 5]);
assert_eq!(c.next().unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
let v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.rchunks(3);
assert_eq!(c.next().unwrap(), &[5, 6, 7]);
assert_eq!(c.next().unwrap(), &[2, 3, 4]);
assert_eq!(c.next().unwrap(), &[0, 1]);
assert_eq!(c.next(), None);
}
#[test]
fn test_rchunks_next_back() {
let v = [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks(2);
assert_eq!(c.next_back().unwrap(), &[0, 1]);
assert_eq!(c.next_back().unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
assert_eq!(c.next_back(), None);
let v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.rchunks(3);
assert_eq!(c.next_back().unwrap(), &[0, 1]);
assert_eq!(c.next_back().unwrap(), &[2, 3, 4]);
assert_eq!(c.next_back().unwrap(), &[5, 6, 7]);
assert_eq!(c.next_back(), None);
}
#[test]
fn test_rchunks_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.rchunks(2);
assert_eq!(c.last().unwrap()[1], 1);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.rchunks(2);
assert_eq!(c2.last().unwrap()[0], 0);
}
#[test]
fn test_rchunks_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.rchunks(2)
.zip(v2.rchunks(2))
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, vec![26, 18, 6]);
}
#[test]
fn test_rchunks_mut_count() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.rchunks_mut(3);
assert_eq!(c.count(), 2);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.rchunks_mut(2);
assert_eq!(c2.count(), 3);
let v3: &mut [i32] = &mut [];
let c3 = v3.rchunks_mut(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_rchunks_mut_nth() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_mut(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c2 = v2.rchunks_mut(3);
assert_eq!(c2.nth(1).unwrap(), &[0, 1]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_mut_nth_back() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_mut(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let mut c2 = v2.rchunks_mut(3);
assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
assert_eq!(c2.next_back(), None);
}
#[test]
fn test_rchunks_mut_next() {
let mut v = [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_mut(2);
assert_eq!(c.next().unwrap(), &mut [4, 5]);
assert_eq!(c.next().unwrap(), &mut [2, 3]);
assert_eq!(c.next().unwrap(), &mut [0, 1]);
assert_eq!(c.next(), None);
let mut v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.rchunks_mut(3);
assert_eq!(c.next().unwrap(), &mut [5, 6, 7]);
assert_eq!(c.next().unwrap(), &mut [2, 3, 4]);
assert_eq!(c.next().unwrap(), &mut [0, 1]);
assert_eq!(c.next(), None);
}
#[test]
fn test_rchunks_mut_next_back() {
let mut v = [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_mut(2);
assert_eq!(c.next_back().unwrap(), &mut [0, 1]);
assert_eq!(c.next_back().unwrap(), &mut [2, 3]);
assert_eq!(c.next_back().unwrap(), &mut [4, 5]);
assert_eq!(c.next_back(), None);
let mut v = [0, 1, 2, 3, 4, 5, 6, 7];
let mut c = v.rchunks_mut(3);
assert_eq!(c.next_back().unwrap(), &mut [0, 1]);
assert_eq!(c.next_back().unwrap(), &mut [2, 3, 4]);
assert_eq!(c.next_back().unwrap(), &mut [5, 6, 7]);
assert_eq!(c.next_back(), None);
}
#[test]
fn test_rchunks_mut_last() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.rchunks_mut(2);
assert_eq!(c.last().unwrap(), &[0, 1]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.rchunks_mut(2);
assert_eq!(c2.last().unwrap(), &[0]);
}
#[test]
fn test_rchunks_mut_zip() {
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
for (a, b) in v1.rchunks_mut(2).zip(v2.rchunks(2)) {
let sum = b.iter().sum::<i32>();
for v in a {
*v += sum;
}
}
assert_eq!(v1, [6, 16, 17, 22, 23]);
}
#[test]
fn test_rchunks_exact_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.rchunks_exact(3);
assert_eq!(c.count(), 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.rchunks_exact(2);
assert_eq!(c2.count(), 2);
let v3: &[i32] = &[];
let c3 = v3.rchunks_exact(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_rchunks_exact_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_exact(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.rchunks_exact(3);
assert_eq!(c2.nth(1).unwrap(), &[1, 2, 3]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_exact_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_exact(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.rchunks_exact(3);
assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_exact_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.rchunks_exact(2);
assert_eq!(c.last().unwrap(), &[0, 1]);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.rchunks_exact(2);
assert_eq!(c2.last().unwrap(), &[1, 2]);
}
#[test]
fn test_rchunks_exact_remainder() {
let v: &[i32] = &[0, 1, 2, 3, 4];
let c = v.rchunks_exact(2);
assert_eq!(c.remainder(), &[0]);
}
#[test]
fn test_rchunks_exact_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.rchunks_exact(2)
.zip(v2.rchunks_exact(2))
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, vec![26, 18]);
}
#[test]
fn test_rchunks_exact_mut_count() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.rchunks_exact_mut(3);
assert_eq!(c.count(), 2);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.rchunks_exact_mut(2);
assert_eq!(c2.count(), 2);
let v3: &mut [i32] = &mut [];
let c3 = v3.rchunks_exact_mut(2);
assert_eq!(c3.count(), 0);
}
#[test]
fn test_rchunks_exact_mut_nth() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_exact_mut(2);
assert_eq!(c.nth(1).unwrap(), &[2, 3]);
assert_eq!(c.next().unwrap(), &[0, 1]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.rchunks_exact_mut(3);
assert_eq!(c2.nth(1).unwrap(), &[1, 2, 3]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_exact_mut_nth_back() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let mut c = v.rchunks_exact_mut(2);
assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
assert_eq!(c.next_back().unwrap(), &[4, 5]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
let mut c2 = v2.rchunks_exact_mut(3);
assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
assert_eq!(c2.next(), None);
}
#[test]
fn test_rchunks_exact_mut_last() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
let c = v.rchunks_exact_mut(2);
assert_eq!(c.last().unwrap(), &[0, 1]);
let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c2 = v2.rchunks_exact_mut(2);
assert_eq!(c2.last().unwrap(), &[1, 2]);
}
#[test]
fn test_rchunks_exact_mut_remainder() {
let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
let c = v.rchunks_exact_mut(2);
assert_eq!(c.into_remainder(), &[0]);
}
#[test]
fn test_rchunks_exact_mut_zip() {
let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
for (a, b) in v1.rchunks_exact_mut(2).zip(v2.rchunks_exact(2)) {
let sum = b.iter().sum::<i32>();
for v in a {
*v += sum;
}
}
assert_eq!(v1, [0, 16, 17, 22, 23]);
}
#[test]
fn test_windows_count() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.windows(3);
assert_eq!(c.count(), 4);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.windows(6);
assert_eq!(c2.count(), 0);
let v3: &[i32] = &[];
let c3 = v3.windows(2);
assert_eq!(c3.count(), 0);
let v4 = &[(); usize::MAX];
let c4 = v4.windows(1);
assert_eq!(c4.count(), usize::MAX);
}
#[test]
fn test_windows_nth() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.windows(2);
assert_eq!(c.nth(2).unwrap()[1], 3);
assert_eq!(c.next().unwrap()[0], 3);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.windows(4);
assert_eq!(c2.nth(1).unwrap()[1], 2);
assert_eq!(c2.next(), None);
}
#[test]
fn test_windows_nth_back() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let mut c = v.windows(2);
assert_eq!(c.nth_back(2).unwrap()[0], 2);
assert_eq!(c.next_back().unwrap()[1], 2);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let mut c2 = v2.windows(4);
assert_eq!(c2.nth_back(1).unwrap()[1], 1);
assert_eq!(c2.next_back(), None);
}
#[test]
fn test_windows_last() {
let v: &[i32] = &[0, 1, 2, 3, 4, 5];
let c = v.windows(2);
assert_eq!(c.last().unwrap()[1], 5);
let v2: &[i32] = &[0, 1, 2, 3, 4];
let c2 = v2.windows(2);
assert_eq!(c2.last().unwrap()[0], 3);
}
#[test]
fn test_windows_zip() {
let v1: &[i32] = &[0, 1, 2, 3, 4];
let v2: &[i32] = &[6, 7, 8, 9, 10];
let res = v1
.windows(2)
.zip(v2.windows(2))
.map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
.collect::<Vec<_>>();
assert_eq!(res, [14, 18, 22, 26]);
}
#[test]
#[allow(const_err)]
fn test_iter_ref_consistency() {
use std::fmt::Debug;
fn test<T: Copy + Debug + PartialEq>(x: T) {
let v: &[T] = &[x, x, x];
let v_ptrs: [*const T; 3] = match v {
[ref v1, ref v2, ref v3] => [v1 as *const _, v2 as *const _, v3 as *const _],
_ => unreachable!(),
};
let len = v.len();
// nth(i)
for i in 0..len {
assert_eq!(&v[i] as *const _, v_ptrs[i]); // check the v_ptrs array, just to be sure
let nth = v.iter().nth(i).unwrap();
assert_eq!(nth as *const _, v_ptrs[i]);
}
assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
// stepping through with nth(0)
{
let mut it = v.iter();
for i in 0..len {
let next = it.nth(0).unwrap();
assert_eq!(next as *const _, v_ptrs[i]);
}
assert_eq!(it.nth(0), None);
}
// next()
{
let mut it = v.iter();
for i in 0..len {
let remaining = len - i;
assert_eq!(it.size_hint(), (remaining, Some(remaining)));
let next = it.next().unwrap();
assert_eq!(next as *const _, v_ptrs[i]);
}
assert_eq!(it.size_hint(), (0, Some(0)));
assert_eq!(it.next(), None, "The final call to next() should return None");
}
// next_back()
{
let mut it = v.iter();
for i in 0..len {
let remaining = len - i;
assert_eq!(it.size_hint(), (remaining, Some(remaining)));
let prev = it.next_back().unwrap();
assert_eq!(prev as *const _, v_ptrs[remaining - 1]);
}
assert_eq!(it.size_hint(), (0, Some(0)));
assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
}
}
fn test_mut<T: Copy + Debug + PartialEq>(x: T) {
let v: &mut [T] = &mut [x, x, x];
let v_ptrs: [*mut T; 3] = match v {
[ref v1, ref v2, ref v3] => {
[v1 as *const _ as *mut _, v2 as *const _ as *mut _, v3 as *const _ as *mut _]
}
_ => unreachable!(),
};
let len = v.len();
// nth(i)
for i in 0..len {
assert_eq!(&mut v[i] as *mut _, v_ptrs[i]); // check the v_ptrs array, just to be sure
let nth = v.iter_mut().nth(i).unwrap();
assert_eq!(nth as *mut _, v_ptrs[i]);
}
assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
// stepping through with nth(0)
{
let mut it = v.iter();
for i in 0..len {
let next = it.nth(0).unwrap();
assert_eq!(next as *const _, v_ptrs[i]);
}
assert_eq!(it.nth(0), None);
}
// next()
{
let mut it = v.iter_mut();
for i in 0..len {
let remaining = len - i;
assert_eq!(it.size_hint(), (remaining, Some(remaining)));
let next = it.next().unwrap();
assert_eq!(next as *mut _, v_ptrs[i]);
}
assert_eq!(it.size_hint(), (0, Some(0)));
assert_eq!(it.next(), None, "The final call to next() should return None");
}
// next_back()
{
let mut it = v.iter_mut();
for i in 0..len {
let remaining = len - i;
assert_eq!(it.size_hint(), (remaining, Some(remaining)));
let prev = it.next_back().unwrap();
assert_eq!(prev as *mut _, v_ptrs[remaining - 1]);
}
assert_eq!(it.size_hint(), (0, Some(0)));
assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
}
}
// Make sure iterators and slice patterns yield consistent addresses for various types,
// including ZSTs.
test(0u32);
test(());
test([0u32; 0]); // ZST with alignment > 0
test_mut(0u32);
test_mut(());
test_mut([0u32; 0]); // ZST with alignment > 0
}
// The current implementation of SliceIndex fails to handle methods
// orthogonally from range types; therefore, it is worth testing
// all of the indexing operations on each input.
mod slice_index {
// This checks all six indexing methods, given an input range that
// should succeed. (it is NOT suitable for testing invalid inputs)
macro_rules! assert_range_eq {
($arr:expr, $range:expr, $expected:expr) => {
let mut arr = $arr;
let mut expected = $expected;
{
let s: &[_] = &arr;
let expected: &[_] = &expected;
assert_eq!(&s[$range], expected, "(in assertion for: index)");
assert_eq!(s.get($range), Some(expected), "(in assertion for: get)");
unsafe {
assert_eq!(
s.get_unchecked($range),
expected,
"(in assertion for: get_unchecked)",
);
}
}
{
let s: &mut [_] = &mut arr;
let expected: &mut [_] = &mut expected;
assert_eq!(&mut s[$range], expected, "(in assertion for: index_mut)",);
assert_eq!(
s.get_mut($range),
Some(&mut expected[..]),
"(in assertion for: get_mut)",
);
unsafe {
assert_eq!(
s.get_unchecked_mut($range),
expected,
"(in assertion for: get_unchecked_mut)",
);
}
}
};
}
// Make sure the macro can actually detect bugs,
// because if it can't, then what are we even doing here?
//
// (Be aware this only demonstrates the ability to detect bugs
// in the FIRST method that panics, as the macro is not designed
// to be used in `should_panic`)
#[test]
#[should_panic(expected = "out of range")]
fn assert_range_eq_can_fail_by_panic() {
assert_range_eq!([0, 1, 2], 0..5, [0, 1, 2]);
}
// (Be aware this only demonstrates the ability to detect bugs
// in the FIRST method it calls, as the macro is not designed
// to be used in `should_panic`)
#[test]
#[should_panic(expected = "==")]
fn assert_range_eq_can_fail_by_inequality() {
assert_range_eq!([0, 1, 2], 0..2, [0, 1, 2]);
}
// Test cases for bad index operations.
//
// This generates `should_panic` test cases for Index/IndexMut
// and `None` test cases for get/get_mut.
macro_rules! panic_cases {
($(
// each test case needs a unique name to namespace the tests
in mod $case_name:ident {
data: $data:expr;
// optional:
//
// one or more similar inputs for which data[input] succeeds,
// and the corresponding output as an array. This helps validate
// "critical points" where an input range straddles the boundary
// between valid and invalid.
// (such as the input `len..len`, which is just barely valid)
$(
good: data[$good:expr] == $output:expr;
)*
bad: data[$bad:expr];
message: $expect_msg:expr;
}
)*) => {$(
mod $case_name {
#[allow(unused_imports)]
use core::ops::Bound;
#[test]
fn pass() {
let mut v = $data;
$( assert_range_eq!($data, $good, $output); )*
{
let v: &[_] = &v;
assert_eq!(v.get($bad), None, "(in None assertion for get)");
}
{
let v: &mut [_] = &mut v;
assert_eq!(v.get_mut($bad), None, "(in None assertion for get_mut)");
}
}
#[test]
#[should_panic(expected = $expect_msg)]
fn index_fail() {
let v = $data;
let v: &[_] = &v;
let _v = &v[$bad];
}
#[test]
#[should_panic(expected = $expect_msg)]
fn index_mut_fail() {
let mut v = $data;
let v: &mut [_] = &mut v;
let _v = &mut v[$bad];
}
}
)*};
}
#[test]
fn simple() {
let v = [0, 1, 2, 3, 4, 5];
assert_range_eq!(v, .., [0, 1, 2, 3, 4, 5]);
assert_range_eq!(v, ..2, [0, 1]);
assert_range_eq!(v, ..=1, [0, 1]);
assert_range_eq!(v, 2.., [2, 3, 4, 5]);
assert_range_eq!(v, 1..4, [1, 2, 3]);
assert_range_eq!(v, 1..=3, [1, 2, 3]);
}
panic_cases! {
in mod rangefrom_len {
data: [0, 1, 2, 3, 4, 5];
good: data[6..] == [];
bad: data[7..];
message: "out of range";
}
in mod rangeto_len {
data: [0, 1, 2, 3, 4, 5];
good: data[..6] == [0, 1, 2, 3, 4, 5];
bad: data[..7];
message: "out of range";
}
in mod rangetoinclusive_len {
data: [0, 1, 2, 3, 4, 5];
good: data[..=5] == [0, 1, 2, 3, 4, 5];
bad: data[..=6];
message: "out of range";
}
in mod rangeinclusive_len {
data: [0, 1, 2, 3, 4, 5];
good: data[0..=5] == [0, 1, 2, 3, 4, 5];
bad: data[0..=6];
message: "out of range";
}
in mod range_len_len {
data: [0, 1, 2, 3, 4, 5];
good: data[6..6] == [];
bad: data[7..7];
message: "out of range";
}
in mod rangeinclusive_len_len {
data: [0, 1, 2, 3, 4, 5];
good: data[6..=5] == [];
bad: data[7..=6];
message: "out of range";
}
in mod boundpair_len {
data: [0, 1, 2, 3, 4, 5];
good: data[(Bound::Included(6), Bound::Unbounded)] == [];
good: data[(Bound::Unbounded, Bound::Included(5))] == [0, 1, 2, 3, 4, 5];
good: data[(Bound::Unbounded, Bound::Excluded(6))] == [0, 1, 2, 3, 4, 5];
good: data[(Bound::Included(0), Bound::Included(5))] == [0, 1, 2, 3, 4, 5];
good: data[(Bound::Included(0), Bound::Excluded(6))] == [0, 1, 2, 3, 4, 5];
good: data[(Bound::Included(2), Bound::Excluded(4))] == [2, 3];
good: data[(Bound::Excluded(1), Bound::Included(4))] == [2, 3, 4];
good: data[(Bound::Excluded(5), Bound::Excluded(6))] == [];
good: data[(Bound::Included(6), Bound::Excluded(6))] == [];
good: data[(Bound::Excluded(5), Bound::Included(5))] == [];
good: data[(Bound::Included(6), Bound::Included(5))] == [];
bad: data[(Bound::Unbounded, Bound::Included(6))];
message: "out of range";
}
}
panic_cases! {
in mod rangeinclusive_exhausted {
data: [0, 1, 2, 3, 4, 5];
good: data[0..=5] == [0, 1, 2, 3, 4, 5];
good: data[{
let mut iter = 0..=5;
iter.by_ref().count(); // exhaust it
iter
}] == [];
// 0..=6 is out of range before exhaustion, so it
// stands to reason that it still would be after.
bad: data[{
let mut iter = 0..=6;
iter.by_ref().count(); // exhaust it
iter
}];
message: "out of range";
}
}
panic_cases! {
in mod range_neg_width {
data: [0, 1, 2, 3, 4, 5];
good: data[4..4] == [];
bad: data[4..3];
message: "but ends at";
}
in mod rangeinclusive_neg_width {
data: [0, 1, 2, 3, 4, 5];
good: data[4..=3] == [];
bad: data[4..=2];
message: "but ends at";
}
in mod boundpair_neg_width {
data: [0, 1, 2, 3, 4, 5];
good: data[(Bound::Included(4), Bound::Excluded(4))] == [];
bad: data[(Bound::Included(4), Bound::Excluded(3))];
message: "but ends at";
}
}
panic_cases! {
in mod rangeinclusive_overflow {
data: [0, 1];
// note: using 0 specifically ensures that the result of overflowing is 0..0,
// so that `get` doesn't simply return None for the wrong reason.
bad: data[0 ..= usize::MAX];
message: "maximum usize";
}
in mod rangetoinclusive_overflow {
data: [0, 1];
bad: data[..= usize::MAX];
message: "maximum usize";
}
in mod boundpair_overflow_end {
data: [0; 1];
bad: data[(Bound::Unbounded, Bound::Included(usize::MAX))];
message: "maximum usize";
}
in mod boundpair_overflow_start {
data: [0; 1];
bad: data[(Bound::Excluded(usize::MAX), Bound::Unbounded)];
message: "maximum usize";
}
} // panic_cases!
}
#[test]
fn test_find_rfind() {
let v = [0, 1, 2, 3, 4, 5];
let mut iter = v.iter();
let mut i = v.len();
while let Some(&elt) = iter.rfind(|_| true) {
i -= 1;
assert_eq!(elt, v[i]);
}
assert_eq!(i, 0);
assert_eq!(v.iter().rfind(|&&x| x <= 3), Some(&3));
}
#[test]
fn test_iter_folds() {
let a = [1, 2, 3, 4, 5]; // len>4 so the unroll is used
assert_eq!(a.iter().fold(0, |acc, &x| 2 * acc + x), 57);
assert_eq!(a.iter().rfold(0, |acc, &x| 2 * acc + x), 129);
let fold = |acc: i32, &x| acc.checked_mul(2)?.checked_add(x);
assert_eq!(a.iter().try_fold(0, &fold), Some(57));
assert_eq!(a.iter().try_rfold(0, &fold), Some(129));
// short-circuiting try_fold, through other methods
let a = [0, 1, 2, 3, 5, 5, 5, 7, 8, 9];
let mut iter = a.iter();
assert_eq!(iter.position(|&x| x == 3), Some(3));
assert_eq!(iter.rfind(|&&x| x == 5), Some(&5));
assert_eq!(iter.len(), 2);
}
#[test]
fn test_rotate_left() {
const N: usize = 600;
let a: &mut [_] = &mut [0; N];
for i in 0..N {
a[i] = i;
}
a.rotate_left(42);
let k = N - 42;
for i in 0..N {
assert_eq!(a[(i + k) % N], i);
}
}
#[test]
fn test_rotate_right() {
const N: usize = 600;
let a: &mut [_] = &mut [0; N];
for i in 0..N {
a[i] = i;
}
a.rotate_right(42);
for i in 0..N {
assert_eq!(a[(i + 42) % N], i);
}
}
#[test]
#[cfg_attr(miri, ignore)] // Miri is too slow
fn brute_force_rotate_test_0() {
// In case of edge cases involving multiple algorithms
let n = 300;
for len in 0..n {
for s in 0..len {
let mut v = Vec::with_capacity(len);
for i in 0..len {
v.push(i);
}
v[..].rotate_right(s);
for i in 0..v.len() {
assert_eq!(v[i], v.len().wrapping_add(i.wrapping_sub(s)) % v.len());
}
}
}
}
#[test]
fn brute_force_rotate_test_1() {
// `ptr_rotate` covers so many kinds of pointer usage, that this is just a good test for
// pointers in general. This uses a `[usize; 4]` to hit all algorithms without overwhelming miri
let n = 30;
for len in 0..n {
for s in 0..len {
let mut v: Vec<[usize; 4]> = Vec::with_capacity(len);
for i in 0..len {
v.push([i, 0, 0, 0]);
}
v[..].rotate_right(s);
for i in 0..v.len() {
assert_eq!(v[i][0], v.len().wrapping_add(i.wrapping_sub(s)) % v.len());
}
}
}
}
#[test]
#[cfg(not(target_arch = "wasm32"))]
fn sort_unstable() {
use core::cmp::Ordering::{Equal, Greater, Less};
use core::slice::heapsort;
use rand::{rngs::StdRng, seq::SliceRandom, Rng, SeedableRng};
// Miri is too slow (but still need to `chain` to make the types match)
let lens = if cfg!(miri) { (2..20).chain(0..0) } else { (2..25).chain(500..510) };
let rounds = if cfg!(miri) { 1 } else { 100 };
let mut v = [0; 600];
let mut tmp = [0; 600];
let mut rng = StdRng::from_entropy();
for len in lens {
let v = &mut v[0..len];
let tmp = &mut tmp[0..len];
for &modulus in &[5, 10, 100, 1000] {
for _ in 0..rounds {
for i in 0..len {
v[i] = rng.gen::<i32>() % modulus;
}
// Sort in default order.
tmp.copy_from_slice(v);
tmp.sort_unstable();
assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
// Sort in ascending order.
tmp.copy_from_slice(v);
tmp.sort_unstable_by(|a, b| a.cmp(b));
assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
// Sort in descending order.
tmp.copy_from_slice(v);
tmp.sort_unstable_by(|a, b| b.cmp(a));
assert!(tmp.windows(2).all(|w| w[0] >= w[1]));
// Test heapsort using `<` operator.
tmp.copy_from_slice(v);
heapsort(tmp, |a, b| a < b);
assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
// Test heapsort using `>` operator.
tmp.copy_from_slice(v);
heapsort(tmp, |a, b| a > b);
assert!(tmp.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.
for i in 0..v.len() {
v[i] = i as i32;
}
v.sort_unstable_by(|_, _| *[Less, Equal, Greater].choose(&mut rng).unwrap());
v.sort_unstable();
for i in 0..v.len() {
assert_eq!(v[i], i as i32);
}
// Should not panic.
[0i32; 0].sort_unstable();
[(); 10].sort_unstable();
[(); 100].sort_unstable();
let mut v = [0xDEADBEEFu64];
v.sort_unstable();
assert!(v == [0xDEADBEEF]);
}
#[test]
#[cfg(not(target_arch = "wasm32"))]
#[cfg_attr(miri, ignore)] // Miri is too slow
fn select_nth_unstable() {
use core::cmp::Ordering::{Equal, Greater, Less};
use rand::rngs::StdRng;
use rand::seq::SliceRandom;
use rand::{Rng, SeedableRng};
let mut rng = StdRng::from_entropy();
for len in (2..21).chain(500..501) {
let mut orig = vec![0; len];
for &modulus in &[5, 10, 1000] {
for _ in 0..10 {
for i in 0..len {
orig[i] = rng.gen::<i32>() % modulus;
}
let v_sorted = {
let mut v = orig.clone();
v.sort();
v
};
// Sort in default order.
for pivot in 0..len {
let mut v = orig.clone();
v.select_nth_unstable(pivot);
assert_eq!(v_sorted[pivot], v[pivot]);
for i in 0..pivot {
for j in pivot..len {
assert!(v[i] <= v[j]);
}
}
}
// Sort in ascending order.
for pivot in 0..len {
let mut v = orig.clone();
let (left, pivot, right) = v.select_nth_unstable_by(pivot, |a, b| a.cmp(b));
assert_eq!(left.len() + right.len(), len - 1);
for l in left {
assert!(l <= pivot);
for r in right.iter_mut() {
assert!(l <= r);
assert!(pivot <= r);
}
}
}
// Sort in descending order.
let sort_descending_comparator = |a: &i32, b: &i32| b.cmp(a);
let v_sorted_descending = {
let mut v = orig.clone();
v.sort_by(sort_descending_comparator);
v
};
for pivot in 0..len {
let mut v = orig.clone();
v.select_nth_unstable_by(pivot, sort_descending_comparator);
assert_eq!(v_sorted_descending[pivot], v[pivot]);
for i in 0..pivot {
for j in pivot..len {
assert!(v[j] <= v[i]);
}
}
}
}
}
}
// Sort at index 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;
}
for pivot in 0..v.len() {
v.select_nth_unstable_by(pivot, |_, _| *[Less, Equal, Greater].choose(&mut rng).unwrap());
v.sort();
for i in 0..v.len() {
assert_eq!(v[i], i as i32);
}
}
// Should not panic.
[(); 10].select_nth_unstable(0);
[(); 10].select_nth_unstable(5);
[(); 10].select_nth_unstable(9);
[(); 100].select_nth_unstable(0);
[(); 100].select_nth_unstable(50);
[(); 100].select_nth_unstable(99);
let mut v = [0xDEADBEEFu64];
v.select_nth_unstable(0);
assert!(v == [0xDEADBEEF]);
}
#[test]
#[should_panic(expected = "index 0 greater than length of slice")]
fn select_nth_unstable_zero_length() {
[0i32; 0].select_nth_unstable(0);
}
#[test]
#[should_panic(expected = "index 20 greater than length of slice")]
fn select_nth_unstable_past_length() {
[0i32; 10].select_nth_unstable(20);
}
pub mod memchr {
use core::slice::memchr::{memchr, memrchr};
// test fallback implementations on all platforms
#[test]
fn matches_one() {
assert_eq!(Some(0), memchr(b'a', b"a"));
}
#[test]
fn matches_begin() {
assert_eq!(Some(0), memchr(b'a', b"aaaa"));
}
#[test]
fn matches_end() {
assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
}
#[test]
fn matches_nul() {
assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
}
#[test]
fn matches_past_nul() {
assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
}
#[test]
fn no_match_empty() {
assert_eq!(None, memchr(b'a', b""));
}
#[test]
fn no_match() {
assert_eq!(None, memchr(b'a', b"xyz"));
}
#[test]
fn matches_one_reversed() {
assert_eq!(Some(0), memrchr(b'a', b"a"));
}
#[test]
fn matches_begin_reversed() {
assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
}
#[test]
fn matches_end_reversed() {
assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
}
#[test]
fn matches_nul_reversed() {
assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
}
#[test]
fn matches_past_nul_reversed() {
assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
}
#[test]
fn no_match_empty_reversed() {
assert_eq!(None, memrchr(b'a', b""));
}
#[test]
fn no_match_reversed() {
assert_eq!(None, memrchr(b'a', b"xyz"));
}
#[test]
fn each_alignment_reversed() {
let mut data = [1u8; 64];
let needle = 2;
let pos = 40;
data[pos] = needle;
for start in 0..16 {
assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
}
}
}
#[test]
fn test_align_to_simple() {
let bytes = [1u8, 2, 3, 4, 5, 6, 7];
let (prefix, aligned, suffix) = unsafe { bytes.align_to::<u16>() };
assert_eq!(aligned.len(), 3);
assert!(prefix == [1] || suffix == [7]);
let expect1 = [1 << 8 | 2, 3 << 8 | 4, 5 << 8 | 6];
let expect2 = [1 | 2 << 8, 3 | 4 << 8, 5 | 6 << 8];
let expect3 = [2 << 8 | 3, 4 << 8 | 5, 6 << 8 | 7];
let expect4 = [2 | 3 << 8, 4 | 5 << 8, 6 | 7 << 8];
assert!(
aligned == expect1 || aligned == expect2 || aligned == expect3 || aligned == expect4,
"aligned={:?} expected={:?} || {:?} || {:?} || {:?}",
aligned,
expect1,
expect2,
expect3,
expect4
);
}
#[test]
fn test_align_to_zst() {
let bytes = [1, 2, 3, 4, 5, 6, 7];
let (prefix, aligned, suffix) = unsafe { bytes.align_to::<()>() };
assert_eq!(aligned.len(), 0);
assert!(prefix == [1, 2, 3, 4, 5, 6, 7] || suffix == [1, 2, 3, 4, 5, 6, 7]);
}
#[test]
fn test_align_to_non_trivial() {
#[repr(align(8))]
struct U64(u64, u64);
#[repr(align(8))]
struct U64U64U32(u64, u64, u32);
let data = [
U64(1, 2),
U64(3, 4),
U64(5, 6),
U64(7, 8),
U64(9, 10),
U64(11, 12),
U64(13, 14),
U64(15, 16),
];
let (prefix, aligned, suffix) = unsafe { data.align_to::<U64U64U32>() };
assert_eq!(aligned.len(), 4);
assert_eq!(prefix.len() + suffix.len(), 2);
}
#[test]
fn test_align_to_empty_mid() {
use core::mem;
// Make sure that we do not create empty unaligned slices for the mid part, even when the
// overall slice is too short to contain an aligned address.
let bytes = [1, 2, 3, 4, 5, 6, 7];
type Chunk = u32;
for offset in 0..4 {
let (_, mid, _) = unsafe { bytes[offset..offset + 1].align_to::<Chunk>() };
assert_eq!(mid.as_ptr() as usize % mem::align_of::<Chunk>(), 0);
}
}
#[test]
fn test_align_to_mut_aliasing() {
let mut val = [1u8, 2, 3, 4, 5];
// `align_to_mut` used to create `mid` in a way that there was some intermediate
// incorrect aliasing, invalidating the resulting `mid` slice.
let (begin, mid, end) = unsafe { val.align_to_mut::<[u8; 2]>() };
assert!(begin.len() == 0);
assert!(end.len() == 1);
mid[0] = mid[1];
assert_eq!(val, [3, 4, 3, 4, 5])
}
#[test]
fn test_slice_partition_dedup_by() {
let mut slice: [i32; 9] = [1, -1, 2, 3, 1, -5, 5, -2, 2];
let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.abs() == b.abs());
assert_eq!(dedup, [1, 2, 3, 1, -5, -2]);
assert_eq!(duplicates, [5, -1, 2]);
}
#[test]
fn test_slice_partition_dedup_empty() {
let mut slice: [i32; 0] = [];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, []);
assert_eq!(duplicates, []);
}
#[test]
fn test_slice_partition_dedup_one() {
let mut slice = [12];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, [12]);
assert_eq!(duplicates, []);
}
#[test]
fn test_slice_partition_dedup_multiple_ident() {
let mut slice = [12, 12, 12, 12, 12, 11, 11, 11, 11, 11, 11];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, [12, 11]);
assert_eq!(duplicates, [12, 12, 12, 12, 11, 11, 11, 11, 11]);
}
#[test]
fn test_slice_partition_dedup_partialeq() {
#[derive(Debug)]
struct Foo(i32, i32);
impl PartialEq for Foo {
fn eq(&self, other: &Foo) -> bool {
self.0 == other.0
}
}
let mut slice = [Foo(0, 1), Foo(0, 5), Foo(1, 7), Foo(1, 9)];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, [Foo(0, 1), Foo(1, 7)]);
assert_eq!(duplicates, [Foo(0, 5), Foo(1, 9)]);
}
#[test]
fn test_copy_within() {
// Start to end, with a RangeTo.
let mut bytes = *b"Hello, World!";
bytes.copy_within(..3, 10);
assert_eq!(&bytes, b"Hello, WorHel");
// End to start, with a RangeFrom.
let mut bytes = *b"Hello, World!";
bytes.copy_within(10.., 0);
assert_eq!(&bytes, b"ld!lo, World!");
// Overlapping, with a RangeInclusive.
let mut bytes = *b"Hello, World!";
bytes.copy_within(0..=11, 1);
assert_eq!(&bytes, b"HHello, World");
// Whole slice, with a RangeFull.
let mut bytes = *b"Hello, World!";
bytes.copy_within(.., 0);
assert_eq!(&bytes, b"Hello, World!");
// Ensure that copying at the end of slice won't cause UB.
let mut bytes = *b"Hello, World!";
bytes.copy_within(13..13, 5);
assert_eq!(&bytes, b"Hello, World!");
bytes.copy_within(5..5, 13);
assert_eq!(&bytes, b"Hello, World!");
}
#[test]
#[should_panic(expected = "range end index 14 out of range for slice of length 13")]
fn test_copy_within_panics_src_too_long() {
let mut bytes = *b"Hello, World!";
// The length is only 13, so 14 is out of bounds.
bytes.copy_within(10..14, 0);
}
#[test]
#[should_panic(expected = "dest is out of bounds")]
fn test_copy_within_panics_dest_too_long() {
let mut bytes = *b"Hello, World!";
// The length is only 13, so a slice of length 4 starting at index 10 is out of bounds.
bytes.copy_within(0..4, 10);
}
#[test]
#[should_panic(expected = "slice index starts at 2 but ends at 1")]
fn test_copy_within_panics_src_inverted() {
let mut bytes = *b"Hello, World!";
// 2 is greater than 1, so this range is invalid.
bytes.copy_within(2..1, 0);
}
#[test]
#[should_panic(expected = "attempted to index slice up to maximum usize")]
fn test_copy_within_panics_src_out_of_bounds() {
let mut bytes = *b"Hello, World!";
// an inclusive range ending at usize::MAX would make src_end overflow
bytes.copy_within(usize::MAX..=usize::MAX, 0);
}
#[test]
fn test_is_sorted() {
let empty: [i32; 0] = [];
assert!([1, 2, 2, 9].is_sorted());
assert!(![1, 3, 2].is_sorted());
assert!([0].is_sorted());
assert!(empty.is_sorted());
assert!(![0.0, 1.0, f32::NAN].is_sorted());
assert!([-2, -1, 0, 3].is_sorted());
assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
assert!(!["c", "bb", "aaa"].is_sorted());
assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
}
#[test]
fn test_slice_run_destructors() {
// Make sure that destructors get run on slice literals
struct Foo<'a> {
x: &'a Cell<isize>,
}
impl<'a> Drop for Foo<'a> {
fn drop(&mut self) {
self.x.set(self.x.get() + 1);
}
}
fn foo(x: &Cell<isize>) -> Foo<'_> {
Foo { x }
}
let x = &Cell::new(0);
{
let l = &[foo(x)];
assert_eq!(l[0].x.get(), 0);
}
assert_eq!(x.get(), 1);
}
#[test]
fn test_const_from_ref() {
const VALUE: &i32 = &1;
const SLICE: &[i32] = core::slice::from_ref(VALUE);
assert!(core::ptr::eq(VALUE, &SLICE[0]))
}
#[test]
fn test_slice_fill_with_uninit() {
// This should not UB. See #87891
let mut a = [MaybeUninit::<u8>::uninit(); 10];
a.fill(MaybeUninit::uninit());
}
#[test]
fn test_swap() {
let mut x = ["a", "b", "c", "d"];
x.swap(1, 3);
assert_eq!(x, ["a", "d", "c", "b"]);
x.swap(0, 3);
assert_eq!(x, ["b", "d", "c", "a"]);
}
mod swap_panics {
#[test]
#[should_panic(expected = "index out of bounds: the len is 4 but the index is 4")]
fn index_a_equals_len() {
let mut x = ["a", "b", "c", "d"];
x.swap(4, 2);
}
#[test]
#[should_panic(expected = "index out of bounds: the len is 4 but the index is 4")]
fn index_b_equals_len() {
let mut x = ["a", "b", "c", "d"];
x.swap(2, 4);
}
#[test]
#[should_panic(expected = "index out of bounds: the len is 4 but the index is 5")]
fn index_a_greater_than_len() {
let mut x = ["a", "b", "c", "d"];
x.swap(5, 2);
}
#[test]
#[should_panic(expected = "index out of bounds: the len is 4 but the index is 5")]
fn index_b_greater_than_len() {
let mut x = ["a", "b", "c", "d"];
x.swap(2, 5);
}
}
#[test]
fn slice_split_array_mut() {
let v = &mut [1, 2, 3, 4, 5, 6][..];
{
let (left, right) = v.split_array_mut::<0>();
assert_eq!(left, &mut []);
assert_eq!(right, [1, 2, 3, 4, 5, 6]);
}
{
let (left, right) = v.split_array_mut::<6>();
assert_eq!(left, &mut [1, 2, 3, 4, 5, 6]);
assert_eq!(right, []);
}
}
#[test]
fn slice_rsplit_array_mut() {
let v = &mut [1, 2, 3, 4, 5, 6][..];
{
let (left, right) = v.rsplit_array_mut::<0>();
assert_eq!(left, [1, 2, 3, 4, 5, 6]);
assert_eq!(right, &mut []);
}
{
let (left, right) = v.rsplit_array_mut::<6>();
assert_eq!(left, []);
assert_eq!(right, &mut [1, 2, 3, 4, 5, 6]);
}
}
#[should_panic]
#[test]
fn slice_split_array_ref_out_of_bounds() {
let v = &[1, 2, 3, 4, 5, 6][..];
v.split_array_ref::<7>();
}
#[should_panic]
#[test]
fn slice_split_array_mut_out_of_bounds() {
let v = &mut [1, 2, 3, 4, 5, 6][..];
v.split_array_mut::<7>();
}
#[should_panic]
#[test]
fn slice_rsplit_array_ref_out_of_bounds() {
let v = &[1, 2, 3, 4, 5, 6][..];
v.rsplit_array_ref::<7>();
}
#[should_panic]
#[test]
fn slice_rsplit_array_mut_out_of_bounds() {
let v = &mut [1, 2, 3, 4, 5, 6][..];
v.rsplit_array_mut::<7>();
}
macro_rules! take_tests {
(slice: &[], $($tts:tt)*) => {
take_tests!(ty: &[()], slice: &[], $($tts)*);
};
(slice: &mut [], $($tts:tt)*) => {
take_tests!(ty: &mut [()], slice: &mut [], $($tts)*);
};
(slice: &$slice:expr, $($tts:tt)*) => {
take_tests!(ty: &[_], slice: &$slice, $($tts)*);
};
(slice: &mut $slice:expr, $($tts:tt)*) => {
take_tests!(ty: &mut [_], slice: &mut $slice, $($tts)*);
};
(ty: $ty:ty, slice: $slice:expr, method: $method:ident, $(($test_name:ident, ($($args:expr),*), $output:expr, $remaining:expr),)*) => {
$(
#[test]
fn $test_name() {
let mut slice: $ty = $slice;
assert_eq!($output, slice.$method($($args)*));
let remaining: $ty = $remaining;
assert_eq!(remaining, slice);
}
)*
};
}
take_tests! {
slice: &[0, 1, 2, 3], method: take,
(take_in_bounds_range_to, (..1), Some(&[0] as _), &[1, 2, 3]),
(take_in_bounds_range_to_inclusive, (..=0), Some(&[0] as _), &[1, 2, 3]),
(take_in_bounds_range_from, (2..), Some(&[2, 3] as _), &[0, 1]),
(take_oob_range_to, (..5), None, &[0, 1, 2, 3]),
(take_oob_range_to_inclusive, (..=4), None, &[0, 1, 2, 3]),
(take_oob_range_from, (5..), None, &[0, 1, 2, 3]),
}
take_tests! {
slice: &mut [0, 1, 2, 3], method: take_mut,
(take_mut_in_bounds_range_to, (..1), Some(&mut [0] as _), &mut [1, 2, 3]),
(take_mut_in_bounds_range_to_inclusive, (..=0), Some(&mut [0] as _), &mut [1, 2, 3]),
(take_mut_in_bounds_range_from, (2..), Some(&mut [2, 3] as _), &mut [0, 1]),
(take_mut_oob_range_to, (..5), None, &mut [0, 1, 2, 3]),
(take_mut_oob_range_to_inclusive, (..=4), None, &mut [0, 1, 2, 3]),
(take_mut_oob_range_from, (5..), None, &mut [0, 1, 2, 3]),
}
take_tests! {
slice: &[1, 2], method: take_first,
(take_first_nonempty, (), Some(&1), &[2]),
}
take_tests! {
slice: &mut [1, 2], method: take_first_mut,
(take_first_mut_nonempty, (), Some(&mut 1), &mut [2]),
}
take_tests! {
slice: &[1, 2], method: take_last,
(take_last_nonempty, (), Some(&2), &[1]),
}
take_tests! {
slice: &mut [1, 2], method: take_last_mut,
(take_last_mut_nonempty, (), Some(&mut 2), &mut [1]),
}
take_tests! {
slice: &[], method: take_first,
(take_first_empty, (), None, &[]),
}
take_tests! {
slice: &mut [], method: take_first_mut,
(take_first_mut_empty, (), None, &mut []),
}
take_tests! {
slice: &[], method: take_last,
(take_last_empty, (), None, &[]),
}
take_tests! {
slice: &mut [], method: take_last_mut,
(take_last_mut_empty, (), None, &mut []),
}
const EMPTY_MAX: &'static [()] = &[(); usize::MAX];
// can't be a constant due to const mutability rules
macro_rules! empty_max_mut {
() => {
&mut [(); usize::MAX] as _
};
}
#[cfg(not(miri))] // Comparing usize::MAX many elements takes forever in Miri (and in rustc without optimizations)
take_tests! {
slice: &[(); usize::MAX], method: take,
(take_in_bounds_max_range_to, (..usize::MAX), Some(EMPTY_MAX), &[(); 0]),
(take_oob_max_range_to_inclusive, (..=usize::MAX), None, EMPTY_MAX),
(take_in_bounds_max_range_from, (usize::MAX..), Some(&[] as _), EMPTY_MAX),
}
#[cfg(not(miri))] // Comparing usize::MAX many elements takes forever in Miri (and in rustc without optimizations)
take_tests! {
slice: &mut [(); usize::MAX], method: take_mut,
(take_mut_in_bounds_max_range_to, (..usize::MAX), Some(empty_max_mut!()), &mut [(); 0]),
(take_mut_oob_max_range_to_inclusive, (..=usize::MAX), None, empty_max_mut!()),
(take_mut_in_bounds_max_range_from, (usize::MAX..), Some(&mut [] as _), empty_max_mut!()),
}