From bb04368f41acccb976ff0df63bed2190b2740d10 Mon Sep 17 00:00:00 2001 From: Bruno BELANYI Date: Sat, 16 Jul 2022 14:05:56 +0200 Subject: [PATCH] Add 'File' enum --- src/board/file.rs | 85 +++++++++++++++++++++++++++++++++++++++++++++++ src/board/mod.rs | 3 ++ 2 files changed, 88 insertions(+) create mode 100644 src/board/file.rs diff --git a/src/board/file.rs b/src/board/file.rs new file mode 100644 index 0000000..a7ab385 --- /dev/null +++ b/src/board/file.rs @@ -0,0 +1,85 @@ +use super::Bitboard; + +/// An enum representing a singular file on a chess board (i.e: the columns). +#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub enum File { + A, + B, + C, + D, + E, + F, + G, + H, +} + +impl File { + const ALL: [File; 8] = [ + File::A, + File::B, + File::C, + File::D, + File::E, + File::F, + File::G, + File::H, + ]; + + /// Iterate over all files in order. + pub fn iter() -> impl Iterator { + Self::ALL.iter().cloned() + } + + /// Convert from a file index into a [File] 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 file index into a [File] 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 [File]. + #[inline(always)] + pub fn index(self) -> usize { + self as usize + } + + /// Turn a [File] into a [Bitboard] of all squares in that file. + #[inline(always)] + pub fn into_bitboard(self) -> Bitboard { + // SAFETY: we know the value is in-bounds + unsafe { *Bitboard::FILES.get_unchecked(self.index()) } + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn from_index() { + assert_eq!(File::from_index(0), File::A); + assert_eq!(File::from_index(1), File::B); + assert_eq!(File::from_index(7), File::H); + } + + #[test] + fn index() { + assert_eq!(File::A.index(), 0); + assert_eq!(File::B.index(), 1); + assert_eq!(File::H.index(), 7); + } + + #[test] + fn into_bitboard() { + assert_eq!(File::A.into_bitboard(), Bitboard::FILES[0]); + assert_eq!(File::B.into_bitboard(), Bitboard::FILES[1]); + assert_eq!(File::H.into_bitboard(), Bitboard::FILES[7]); + } +} diff --git a/src/board/mod.rs b/src/board/mod.rs index ef264e1..7923cab 100644 --- a/src/board/mod.rs +++ b/src/board/mod.rs @@ -1,6 +1,9 @@ pub mod bitboard; pub use bitboard::*; +pub mod file; +pub use file::*; + pub mod rank; pub use rank::*;