From 63c5d2dc3465411dfdd74c5c95efe4b095a7a52f Mon Sep 17 00:00:00 2001 From: Bruno BELANYI Date: Mon, 18 Jul 2022 13:27:03 +0200 Subject: [PATCH] Add 'CastleRights' enum --- src/board/castle_rights.rs | 55 ++++++++++++++++++++++++++++++++++++++ src/board/mod.rs | 3 +++ 2 files changed, 58 insertions(+) create mode 100644 src/board/castle_rights.rs diff --git a/src/board/castle_rights.rs b/src/board/castle_rights.rs new file mode 100644 index 0000000..9ea7ad6 --- /dev/null +++ b/src/board/castle_rights.rs @@ -0,0 +1,55 @@ +/// Current castle rights for a player. +#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub enum CastleRights { + /// No castling allowed. + NoSide, + /// King-side castling only. + KingSide, + /// Queen-side castling only. + QueenSide, + /// Either side allowed. + BothSides, +} + +impl CastleRights { + /// Convert from a castle rights index into a [CastleRights] type. + #[inline(always)] + pub fn from_index(index: usize) -> Self { + assert!(index < 4); + // SAFETY: we know the value is in-bounds + unsafe { Self::from_index_unchecked(index) } + } + + /// Convert from a castle rights index into a [CastleRights] 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 [CastleRights]. + #[inline(always)] + pub fn index(self) -> usize { + self as usize + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn from_index() { + assert_eq!(CastleRights::from_index(0), CastleRights::NoSide); + assert_eq!(CastleRights::from_index(1), CastleRights::KingSide); + assert_eq!(CastleRights::from_index(2), CastleRights::QueenSide); + assert_eq!(CastleRights::from_index(3), CastleRights::BothSides); + } + + #[test] + fn index() { + assert_eq!(CastleRights::NoSide.index(), 0); + assert_eq!(CastleRights::KingSide.index(), 1); + assert_eq!(CastleRights::QueenSide.index(), 2); + assert_eq!(CastleRights::BothSides.index(), 3); + } +} diff --git a/src/board/mod.rs b/src/board/mod.rs index 6a29cbe..ad91192 100644 --- a/src/board/mod.rs +++ b/src/board/mod.rs @@ -1,6 +1,9 @@ pub mod bitboard; pub use bitboard::*; +pub mod castle_rights; +pub use castle_rights::*; + pub mod color; pub use color::*;