engine/src/bitboard.rs

@@ -1 +1,2 @@
-mod attackmaps;
+mod attackmaps;
+mod utils;

engine/src/bitboard/utils.rs

@@ -0,0 +1,99 @@
+#[inline(always)]
+pub fn pop_lsb(value: &mut u64) -> usize {
+  let idx = value.trailing_zeros() as usize;
+  *value &= !(1 << idx);
+  return idx;
+}
+
+#[inline(always)]
+pub fn pop_msb(value: &mut u64) -> usize {
+  let idx = 63 - value.leading_zeros() as usize;
+  *value &= !(1 << idx);
+  return idx;
+}
+
+const RANK_NUMBERS: [char; 8] = ['1', '2', '3', '4', '5', '6', '7', '8'];
+const FILE_LETTERS: [char; 8] = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
+pub fn notation_from_square_number(sq: u8) -> String {
+  let row = sq / 8;
+  let col = sq % 8;
+  let mut notation = String::new();
+
+  let row_not = RANK_NUMBERS[row as usize];
+  let col_not = FILE_LETTERS[col as usize];
+
+  notation.push(col_not);
+  notation.push(row_not);
+  return notation;
+}
+
+
+// <----- TESTS ----->
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn pop_lsb_test() {
+
+    // test setup
+    let test_values: [u64; 6] = [
+      0x8000_0000_0000_0000,
+      0x4E91_CF05_713E_451B,
+      0xD588_2D58_6962_34B0,
+      0x9581_3335_DCAB_1DD4,
+      0xBEAC_DBE0_903A_AC00,
+      0x01E8_C895_A6F0_0000
+    ];
+    let expected_values: [usize; 6] = [63, 0, 4, 2, 10, 20];
+
+    // tests
+    for index in 0..6 {
+      let mut test_value = test_values[index];
+      assert_eq!(pop_lsb(&mut test_value), expected_values[index])
+    }
+  }
+
+  #[test]
+  fn pop_msb_test() {
+    // test setup
+    let test_values: [u64; 6] = [
+      0x86D6_8EB0_96A8_8D1C,
+      0x0000_0000_0000_0001,
+      0x3809_24AF_A7AE_8129,
+      0x0277_DA36_3B31_86D9,
+      0x0000_C1C3_201C_0DB1,
+      0x0000_0203_0DE4_E944
+    ];
+    let expected_values: [usize; 6] = [63, 0, 61, 57, 47, 41];
+
+    // tests
+    for index in 0..6 {
+      let mut test_value = test_values[index];
+      assert_eq!(pop_msb(&mut test_value), expected_values[index])
+    }
+  }
+
+  #[test]
+  fn notation_from_square_number_test() {
+    // test setup
+    let square_indices: [u8; 8] = [1, 12, 22, 27, 32, 47, 53, 58];
+    let notations: [String; 8] = [
+      String::from("b1"),
+      String::from("e2"),
+      String::from("g3"),
+      String::from("d4"),
+      String::from("a5"),
+      String::from("h6"),
+      String::from("f7"),
+      String::from("c8")
+    ];
+
+    // tests
+    for index in 0..8 {
+      let notation = notation_from_square_number(square_indices[index].clone());
+      assert_eq!(notation, notations[index]);
+    }
+  }
+}