seer/src/board/bitboard/iterator.rs
Bruno BELANYI b3222276ab
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Improve 'board::BitboardIterator'
* Accurate 'size_hint'.
* Exact size.
* Fused iterator (keeps returning 'None' after returning 'None' once).
2022-07-18 18:21:16 +02:00

28 lines
757 B
Rust

/// An [Iterator](std::iter::Iterator) of [Square](crate::board::Square) contained in a
/// [Bitboard](crate::board::Bitboard).
pub struct BitboardIterator(pub(crate) u64);
impl Iterator for BitboardIterator {
type Item = crate::board::Square;
fn next(&mut self) -> Option<Self::Item> {
if self.0 == 0 {
None
} else {
let lsb = self.0.trailing_zeros() as usize;
self.0 ^= 1 << lsb;
Some(crate::board::Square::from_index(lsb))
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let size = self.0.count_ones() as usize;
(size, Some(size))
}
}
impl ExactSizeIterator for BitboardIterator {}
impl std::iter::FusedIterator for BitboardIterator {}