WIP

bitboard/src/bit_scanner.rs

@@ -1,8 +1,10 @@
 // Eryn Wells <eryn@erynwells.me>
 
+use chessfriend_core::Square;
+
 macro_rules! bit_scanner {
     ($name:ident) => {
-        pub(crate) struct $name {
+        pub struct $name {
             bits: u64,
             shift: usize,
         }
@@ -18,8 +20,15 @@ macro_rules! bit_scanner {
 bit_scanner!(LeadingBitScanner);
 bit_scanner!(TrailingBitScanner);
 
+fn _index_to_square(index: usize) -> Square {
+    unsafe {
+        #[allow(clippy::cast_possible_truncation)]
+        Square::from_index_unchecked(index as u8)
+    }
+}
+
 impl Iterator for LeadingBitScanner {
-    type Item = usize;
+    type Item = Square;
 
     fn next(&mut self) -> Option<Self::Item> {
         let u64bits = u64::BITS as usize;
@@ -40,12 +49,12 @@ impl Iterator for LeadingBitScanner {
         // Shift 1 additional place to account for the 1 that `leading_zeros` found.
         self.shift += leading_zeros + 1;
 
-        Some(position)
+        Some(_index_to_square(position))
     }
 }
 
 impl Iterator for TrailingBitScanner {
-    type Item = usize;
+    type Item = Square;
 
     fn next(&mut self) -> Option<Self::Item> {
         let u64bits = u64::BITS as usize;
@@ -66,7 +75,7 @@ impl Iterator for TrailingBitScanner {
         // Shift 1 additional place to account for the 1 that `leading_zeros` found.
         self.shift += trailing_zeros + 1;
 
-        Some(position)
+        Some(_index_to_square(position))
     }
 }
 
@@ -83,17 +92,17 @@ mod tests {
     #[test]
     fn leading_one() {
         let mut scanner = LeadingBitScanner::new(1);
-        assert_eq!(scanner.next(), Some(0));
+        assert_eq!(scanner.next(), Some(Square::A1));
         assert_eq!(scanner.next(), None);
     }
 
     #[test]
     fn leading_complex() {
         let mut scanner = LeadingBitScanner::new(0b_1100_0101);
-        assert_eq!(scanner.next(), Some(7));
-        assert_eq!(scanner.next(), Some(6));
-        assert_eq!(scanner.next(), Some(2));
-        assert_eq!(scanner.next(), Some(0));
+        assert_eq!(scanner.next(), Some(Square::H1));
+        assert_eq!(scanner.next(), Some(Square::G1));
+        assert_eq!(scanner.next(), Some(Square::C1));
+        assert_eq!(scanner.next(), Some(Square::A1));
         assert_eq!(scanner.next(), None);
     }
 
@@ -106,17 +115,17 @@ mod tests {
     #[test]
     fn trailing_one() {
         let mut scanner = TrailingBitScanner::new(1);
-        assert_eq!(scanner.next(), Some(0));
+        assert_eq!(scanner.next(), Some(Square::A1));
         assert_eq!(scanner.next(), None);
     }
 
     #[test]
     fn trailing_complex() {
         let mut scanner = TrailingBitScanner::new(0b_1100_0101);
-        assert_eq!(scanner.next(), Some(0));
-        assert_eq!(scanner.next(), Some(2));
-        assert_eq!(scanner.next(), Some(6));
-        assert_eq!(scanner.next(), Some(7));
+        assert_eq!(scanner.next(), Some(Square::A1));
+        assert_eq!(scanner.next(), Some(Square::C1));
+        assert_eq!(scanner.next(), Some(Square::G1));
+        assert_eq!(scanner.next(), Some(Square::H1));
         assert_eq!(scanner.next(), None);
     }
 }