nearby/presence/np_adv/src/array_vec.rs - beto-core - Git at Google

 // Copyright 2023 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 //! Provides an [`ArrayVecOption`] wrapper implementation over [`ArrayVec`],
 //! which stores all the elements in an `Option` in order to satisfy
 //! `ArrayVec`'s requirement that the elements must implement `Default`.

 use tinyvec::{ArrayVec, ArrayVecIterator};
 #[cfg(any(test, feature = "alloc"))]
 extern crate alloc;
 #[cfg(any(test, feature = "alloc"))]
 use alloc::vec::Vec;

 /// A wrapper of [`ArrayVec`] that stores it values as [`Option`], in order to
 /// satisfy `ArrayVec`'s requirement that the elements must implement `Default`.
 /// The implementation guarantees that any items in the wrapped `ArrayVec`
 /// within `0..len` is `Some`, and therefore will not panic when unwrapped.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ArrayVecOption<A, const N: usize>(ArrayVec<[Option<A>; N]>);

 // Cannot derive due to https://github.com/rust-lang/rust/issues/74462
 impl<A, const N: usize> Default for ArrayVecOption<A, N> {
     fn default() -> Self {
         Self(Default::default())
     }
 }

 /// Iterator type returned by `ArrayVecOption.iter()`, which can be used as
 /// `impl Iterator<Item = &A>`
 pub type ArrayVecOptionRefIter<'a, A> =
     core::iter::Map<core::slice::Iter<'a, Option<A>>, fn(&'a Option<A>) -> &'a A>;

 /// Iterator type returned by `ArrayVecOption.into_iter()`, which can be used as
 /// `impl Iterator<Item = A>`
 pub type ArrayVecOptionIntoIter<A, const N: usize> =
     core::iter::Map<ArrayVecIterator<[Option<A>; N]>, fn(Option<A>) -> A>;

 impl<A, const N: usize> ArrayVecOption<A, N> {
     /// Returns an iterator over this vec.
     pub fn iter(&self) -> ArrayVecOptionRefIter<A> {
         self.0
             .iter()
             .map(|v| v.as_ref().expect("ArrayVecOption value before .len() should not be None"))
     }

     /// The length of the vec (in elements).
     pub fn len(&self) -> usize {
         self.0.len()
     }

     /// Checks if the length is 0.
     pub fn is_empty(&self) -> bool {
         self.0.is_empty()
     }

     /// Returns the first element of the vec, or `None` if it is empty.
     pub fn first(&self) -> Option<&A> {
         self.iter().next()
     }

     /// Place an element onto the end of the vec.
     ///
     /// # Panics
     /// * If the length of the vec would overflow the capacity.
     pub fn push(&mut self, value: A) {
         self.0.push(Some(value))
     }

     /// Returns a reference to an element at the given index.
     pub fn get(&self, index: usize) -> Option<&A> {
         self.0.get(index).and_then(|opt| opt.as_ref())
     }

     /// Sorts the slice with a key extraction function, but might not preserve
     /// the order of equal elements.
     ///
     /// This sort is unstable (i.e., may reorder equal elements), in-place
     /// (i.e., does not allocate), and *O*(*m* \* *n* \* log(*n*)) worst-case,
     /// where the key function is *O*(*m*).
     pub fn sort_unstable_by_key<K: Ord>(&mut self, f: impl Fn(&A) -> K) {
         self.0.sort_unstable_by_key(|a| {
             f(a.as_ref().expect("Iterated values in ArrayVecOption should never be None"))
         })
     }

     /// Remove an element, swapping the end of the vec into its place.
     pub fn swap_remove(&mut self, index: usize) -> A {
         self.0.swap_remove(index).expect("since index is is bounds, the value at index will always be Some which is safe to unwrap")
     }

     /// Converts this vector into a regular `Vec`, unwrapping all of the
     /// `Option` in the process.
     #[cfg(any(test, feature = "alloc"))]
     pub fn into_vec(self) -> Vec<A> {
         self.into_iter().collect()
     }
 }

 impl<A, const N: usize> IntoIterator for ArrayVecOption<A, N> {
     type Item = A;
     type IntoIter = ArrayVecOptionIntoIter<A, N>;
     fn into_iter(self) -> Self::IntoIter {
         self.0
             .into_iter()
             .map(|v| v.expect("ArrayVecOption value before .len() should not be None"))
     }
 }

 // Implement `FromIterator` to enable `iter.collect::<ArrayVecOption<_>>()`
 impl<A, const N: usize> FromIterator<A> for ArrayVecOption<A, N> {
     fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> Self {
         Self(iter.into_iter().map(Some).collect())
     }
 }

 impl<A, const N: usize> core::ops::Index<usize> for ArrayVecOption<A, N> {
     type Output = A;
     fn index(&self, index: usize) -> &Self::Output {
         self.0[index].as_ref().expect("This panics if provided index is out of bounds")
     }
 }

 #[cfg(test)]
 mod test {
     extern crate std;
     use super::ArrayVecOption;
     use std::vec;

     #[test]
     fn test_default_array_vec() {
         let vec = ArrayVecOption::<u32, 5>::default();
         assert_eq!(0, vec.len());
         assert_eq!(None, vec.iter().next());
         assert!(vec.is_empty());
         assert_eq!(None, vec.first());
         assert_eq!(None, vec.get(0));
         assert_eq!(vec![0_u32; 0], vec.into_vec());
     }

     #[test]
     fn test_array_vec_with_contents() {
         let mut vec = ArrayVecOption::<u32, 5>::default();
         vec.push(1);
         vec.push(2);
         vec.push(3);
         vec.push(4);
         vec.push(5);
         assert_eq!(5, vec.len());
         let mut iter = vec.iter();
         assert_eq!(Some(&1_u32), iter.next());
         assert_eq!(Some(&2_u32), iter.next());
         assert_eq!(Some(&3_u32), iter.next());
         assert_eq!(Some(&4_u32), iter.next());
         assert_eq!(Some(&5_u32), iter.next());
         assert_eq!(None, iter.next());
         assert!(!vec.is_empty());
         assert_eq!(Some(&1_u32), vec.first());
         assert_eq!(Some(&5_u32), vec.get(4));
         assert_eq!(vec![1_u32, 2, 3, 4, 5], vec.clone().into_vec());

         let _ = vec.swap_remove(2);
         assert_eq!(vec![1_u32, 2, 5, 4], vec.clone().into_vec());
     }

     #[test]
     #[should_panic]
     fn test_array_vec_push_overflow() {
         let mut vec = ArrayVecOption::<u32, 5>::default();
         vec.push(1);
         vec.push(2);
         vec.push(3);
         vec.push(4);
         vec.push(5);
         vec.push(6);
     }

     #[test]
     fn test_sort() {
         let mut vec = ArrayVecOption::<u32, 5>::default();
         vec.push(3);
         vec.push(1);
         vec.push(4);
         vec.push(1);
         vec.push(2);
         vec.sort_unstable_by_key(|k| *k);
         assert_eq!(vec![1_u32, 1, 2, 3, 4], vec.clone().into_vec());
     }

     #[test]
     fn test_collect() {
         let vec: ArrayVecOption<u32, 5> = [5_u32, 4, 3, 2, 1].into_iter().collect();
         assert_eq!(vec![5_u32, 4, 3, 2, 1], vec.clone().into_vec());
     }
 }
	// Copyright 2023 Google LLC
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	//! Provides an [`ArrayVecOption`] wrapper implementation over [`ArrayVec`],
	//! which stores all the elements in an `Option` in order to satisfy
	//! `ArrayVec`'s requirement that the elements must implement `Default`.

	use tinyvec::{ArrayVec, ArrayVecIterator};
	#[cfg(any(test, feature = "alloc"))]
	extern crate alloc;
	#[cfg(any(test, feature = "alloc"))]
	use alloc::vec::Vec;

	/// A wrapper of [`ArrayVec`] that stores it values as [`Option`], in order to
	/// satisfy `ArrayVec`'s requirement that the elements must implement `Default`.
	/// The implementation guarantees that any items in the wrapped `ArrayVec`
	/// within `0..len` is `Some`, and therefore will not panic when unwrapped.
	#[derive(Debug, Clone, PartialEq, Eq)]
	pub struct ArrayVecOption<A, const N: usize>(ArrayVec<[Option<A>; N]>);

	// Cannot derive due to https://github.com/rust-lang/rust/issues/74462
	impl<A, const N: usize> Default for ArrayVecOption<A, N> {
	fn default() -> Self {
	Self(Default::default())
	}
	}

	/// Iterator type returned by `ArrayVecOption.iter()`, which can be used as
	/// `impl Iterator<Item = &A>`
	pub type ArrayVecOptionRefIter<'a, A> =
	core::iter::Map<core::slice::Iter<'a, Option<A>>, fn(&'a Option<A>) -> &'a A>;

	/// Iterator type returned by `ArrayVecOption.into_iter()`, which can be used as
	/// `impl Iterator<Item = A>`
	pub type ArrayVecOptionIntoIter<A, const N: usize> =
	core::iter::Map<ArrayVecIterator<[Option<A>; N]>, fn(Option<A>) -> A>;

	impl<A, const N: usize> ArrayVecOption<A, N> {
	/// Returns an iterator over this vec.
	pub fn iter(&self) -> ArrayVecOptionRefIter<A> {
	self.0
	.iter()
	.map(\|v\| v.as_ref().expect("ArrayVecOption value before .len() should not be None"))
	}

	/// The length of the vec (in elements).
	pub fn len(&self) -> usize {
	self.0.len()
	}

	/// Checks if the length is 0.
	pub fn is_empty(&self) -> bool {
	self.0.is_empty()
	}

	/// Returns the first element of the vec, or `None` if it is empty.
	pub fn first(&self) -> Option<&A> {
	self.iter().next()
	}

	/// Place an element onto the end of the vec.
	///
	/// # Panics
	/// * If the length of the vec would overflow the capacity.
	pub fn push(&mut self, value: A) {
	self.0.push(Some(value))
	}

	/// Returns a reference to an element at the given index.
	pub fn get(&self, index: usize) -> Option<&A> {
	self.0.get(index).and_then(\|opt\| opt.as_ref())
	}

	/// Sorts the slice with a key extraction function, but might not preserve
	/// the order of equal elements.
	///
	/// This sort is unstable (i.e., may reorder equal elements), in-place
	/// (i.e., does not allocate), and O(m \* n \* log(n)) worst-case,
	/// where the key function is O(m).
	pub fn sort_unstable_by_key<K: Ord>(&mut self, f: impl Fn(&A) -> K) {
	self.0.sort_unstable_by_key(\|a\| {
	f(a.as_ref().expect("Iterated values in ArrayVecOption should never be None"))
	})
	}

	/// Remove an element, swapping the end of the vec into its place.
	pub fn swap_remove(&mut self, index: usize) -> A {
	self.0.swap_remove(index).expect("since index is is bounds, the value at index will always be Some which is safe to unwrap")
	}

	/// Converts this vector into a regular `Vec`, unwrapping all of the
	/// `Option` in the process.
	#[cfg(any(test, feature = "alloc"))]
	pub fn into_vec(self) -> Vec<A> {
	self.into_iter().collect()
	}
	}

	impl<A, const N: usize> IntoIterator for ArrayVecOption<A, N> {
	type Item = A;
	type IntoIter = ArrayVecOptionIntoIter<A, N>;
	fn into_iter(self) -> Self::IntoIter {
	self.0
	.into_iter()
	.map(\|v\| v.expect("ArrayVecOption value before .len() should not be None"))
	}
	}

	// Implement `FromIterator` to enable `iter.collect::<ArrayVecOption<_>>()`
	impl<A, const N: usize> FromIterator<A> for ArrayVecOption<A, N> {
	fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> Self {
	Self(iter.into_iter().map(Some).collect())
	}
	}

	impl<A, const N: usize> core::ops::Index<usize> for ArrayVecOption<A, N> {
	type Output = A;
	fn index(&self, index: usize) -> &Self::Output {
	self.0[index].as_ref().expect("This panics if provided index is out of bounds")
	}
	}

	#[cfg(test)]
	mod test {
	extern crate std;
	use super::ArrayVecOption;
	use std::vec;

	#[test]
	fn test_default_array_vec() {
	let vec = ArrayVecOption::<u32, 5>::default();
	assert_eq!(0, vec.len());
	assert_eq!(None, vec.iter().next());
	assert!(vec.is_empty());
	assert_eq!(None, vec.first());
	assert_eq!(None, vec.get(0));
	assert_eq!(vec![0_u32; 0], vec.into_vec());
	}

	#[test]
	fn test_array_vec_with_contents() {
	let mut vec = ArrayVecOption::<u32, 5>::default();
	vec.push(1);
	vec.push(2);
	vec.push(3);
	vec.push(4);
	vec.push(5);
	assert_eq!(5, vec.len());
	let mut iter = vec.iter();
	assert_eq!(Some(&1_u32), iter.next());
	assert_eq!(Some(&2_u32), iter.next());
	assert_eq!(Some(&3_u32), iter.next());
	assert_eq!(Some(&4_u32), iter.next());
	assert_eq!(Some(&5_u32), iter.next());
	assert_eq!(None, iter.next());
	assert!(!vec.is_empty());
	assert_eq!(Some(&1_u32), vec.first());
	assert_eq!(Some(&5_u32), vec.get(4));
	assert_eq!(vec![1_u32, 2, 3, 4, 5], vec.clone().into_vec());

	let _ = vec.swap_remove(2);
	assert_eq!(vec![1_u32, 2, 5, 4], vec.clone().into_vec());
	}

	#[test]
	#[should_panic]
	fn test_array_vec_push_overflow() {
	let mut vec = ArrayVecOption::<u32, 5>::default();
	vec.push(1);
	vec.push(2);
	vec.push(3);
	vec.push(4);
	vec.push(5);
	vec.push(6);
	}

	#[test]
	fn test_sort() {
	let mut vec = ArrayVecOption::<u32, 5>::default();
	vec.push(3);
	vec.push(1);
	vec.push(4);
	vec.push(1);
	vec.push(2);
	vec.sort_unstable_by_key(\|k\| *k);
	assert_eq!(vec![1_u32, 1, 2, 3, 4], vec.clone().into_vec());
	}

	#[test]
	fn test_collect() {
	let vec: ArrayVecOption<u32, 5> = [5_u32, 4, 3, 2, 1].into_iter().collect();
	assert_eq!(vec![5_u32, 4, 3, 2, 1], vec.clone().into_vec());
	}
	}