b33e234155
The return of the GroupBy and GroupByMut iterators on slice According to https://github.com/rust-lang/rfcs/pull/2477#issuecomment-742034372, I am opening this PR again, this time I implemented it in safe Rust only, it is therefore much easier to read and is completely safe. This PR proposes to add two new methods to the slice, the `group_by` and `group_by_mut`. These two methods provide a way to iterate over non-overlapping sub-slices of a base slice that are separated by the predicate given by the user (e.g. `Partial::eq`, `|a, b| a.abs() < b.abs()`). ```rust let slice = &[1, 1, 1, 3, 3, 2, 2, 2]; let mut iter = slice.group_by(|a, b| a == b); assert_eq!(iter.next(), Some(&[1, 1, 1][..])); assert_eq!(iter.next(), Some(&[3, 3][..])); assert_eq!(iter.next(), Some(&[2, 2, 2][..])); assert_eq!(iter.next(), None); ``` [An RFC](https://github.com/rust-lang/rfcs/pull/2477) was open 2 years ago but wasn't necessary.
64 lines
1.6 KiB
Rust
64 lines
1.6 KiB
Rust
#![feature(allocator_api)]
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#![feature(box_syntax)]
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#![feature(cow_is_borrowed)]
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#![feature(const_cow_is_borrowed)]
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#![feature(drain_filter)]
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#![feature(exact_size_is_empty)]
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#![feature(new_uninit)]
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#![feature(pattern)]
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#![feature(str_split_once)]
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#![feature(trusted_len)]
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#![feature(try_reserve)]
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#![feature(unboxed_closures)]
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#![feature(associated_type_bounds)]
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#![feature(binary_heap_into_iter_sorted)]
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#![feature(binary_heap_drain_sorted)]
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#![feature(slice_ptr_get)]
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#![feature(split_inclusive)]
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#![feature(binary_heap_retain)]
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#![feature(inplace_iteration)]
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#![feature(iter_map_while)]
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#![feature(int_bits_const)]
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#![feature(vecdeque_binary_search)]
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#![feature(slice_group_by)]
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use std::collections::hash_map::DefaultHasher;
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use std::hash::{Hash, Hasher};
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mod arc;
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mod binary_heap;
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mod borrow;
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mod boxed;
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mod btree_set_hash;
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mod cow_str;
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mod fmt;
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mod heap;
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mod linked_list;
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mod rc;
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mod slice;
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mod str;
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mod string;
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mod vec;
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mod vec_deque;
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fn hash<T: Hash>(t: &T) -> u64 {
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let mut s = DefaultHasher::new();
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t.hash(&mut s);
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s.finish()
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}
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// FIXME: Instantiated functions with i128 in the signature is not supported in Emscripten.
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// See https://github.com/kripken/emscripten-fastcomp/issues/169
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#[cfg(not(target_os = "emscripten"))]
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#[test]
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fn test_boxed_hasher() {
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let ordinary_hash = hash(&5u32);
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let mut hasher_1 = Box::new(DefaultHasher::new());
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5u32.hash(&mut hasher_1);
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assert_eq!(ordinary_hash, hasher_1.finish());
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let mut hasher_2 = Box::new(DefaultHasher::new()) as Box<dyn Hasher>;
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5u32.hash(&mut hasher_2);
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assert_eq!(ordinary_hash, hasher_2.finish());
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}
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