From 4eff49f36795e1e2601f69ad73c915e968747ace Mon Sep 17 00:00:00 2001 From: Bruno BELANYI Date: Sat, 16 Jul 2022 14:05:49 +0200 Subject: [PATCH] Add 'Rank' enum --- src/board/mod.rs | 3 ++ src/board/rank.rs | 85 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) create mode 100644 src/board/rank.rs diff --git a/src/board/mod.rs b/src/board/mod.rs index 06a7d91..ef264e1 100644 --- a/src/board/mod.rs +++ b/src/board/mod.rs @@ -1,5 +1,8 @@ pub mod bitboard; pub use bitboard::*; +pub mod rank; +pub use rank::*; + pub mod square; pub use square::*; diff --git a/src/board/rank.rs b/src/board/rank.rs new file mode 100644 index 0000000..fab3cdd --- /dev/null +++ b/src/board/rank.rs @@ -0,0 +1,85 @@ +use super::Bitboard; + +/// An enum representing a singular rank on a chess board (i.e: the rows). +#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub enum Rank { + First, + Second, + Third, + Fourth, + Fifth, + Sixth, + Seventh, + Eighth, +} + +impl Rank { + const ALL: [Rank; 8] = [ + Rank::First, + Rank::Second, + Rank::Third, + Rank::Fourth, + Rank::Fifth, + Rank::Sixth, + Rank::Seventh, + Rank::Eighth, + ]; + + /// Iterate over all ranks in order. + pub fn iter() -> impl Iterator { + Self::ALL.iter().cloned() + } + + /// Convert from a rank index into a [Rank] type. + #[inline(always)] + pub fn from_index(index: usize) -> Self { + assert!(index < 8); + // SAFETY: we know the value is in-bounds + unsafe { Self::from_index_unchecked(index) } + } + + /// Convert from a rank index into a [Rank] type, no bounds checking. + #[inline(always)] + pub unsafe fn from_index_unchecked(index: usize) -> Self { + std::mem::transmute(index as u8) + } + + /// Return the index of a given [Rank]. + #[inline(always)] + pub fn index(self) -> usize { + self as usize + } + + /// Turn a [Rank] into a [Bitboard] of all squares in that rank. + #[inline(always)] + pub fn into_bitboard(self) -> Bitboard { + // SAFETY: we know the value is in-bounds + unsafe { *Bitboard::RANKS.get_unchecked(self.index()) } + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn from_index() { + assert_eq!(Rank::from_index(0), Rank::First); + assert_eq!(Rank::from_index(1), Rank::Second); + assert_eq!(Rank::from_index(7), Rank::Eighth); + } + + #[test] + fn index() { + assert_eq!(Rank::First.index(), 0); + assert_eq!(Rank::Second.index(), 1); + assert_eq!(Rank::Eighth.index(), 7); + } + + #[test] + fn into_bitboard() { + assert_eq!(Rank::First.into_bitboard(), Bitboard::RANKS[0]); + assert_eq!(Rank::Second.into_bitboard(), Bitboard::RANKS[1]); + assert_eq!(Rank::Eighth.into_bitboard(), Bitboard::RANKS[7]); + } +}