diff options
Diffstat (limited to 'model/src/moves_iter.rs')
| -rw-r--r-- | model/src/moves_iter.rs | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/model/src/moves_iter.rs b/model/src/moves_iter.rs new file mode 100644 index 0000000..307ee96 --- /dev/null +++ b/model/src/moves_iter.rs @@ -0,0 +1,143 @@ +use crate::moves::{Move, MoveDirection};
+use crate::possible_moves::PossibleMoves;
+
+const FORWARD_LEFT_SLIDE_SQUARES: [usize; 33] = [
+ 1, 3, 3, 4, 6, 6, 7, 8, 9, 12, 12, 12, 13, 14, 15, 16, 17, 19, 19, 20, 21, 22, 23, 24, 27, 27,
+ 27, 28, 29, 30, 32, 32, 32,
+];
+const FORWARD_RIGHT_SLIDE_SQUARES: [usize; 33] = [
+ 2, 2, 3, 4, 6, 6, 7, 8, 10, 10, 12, 12, 13, 14, 15, 16, 18, 18, 19, 20, 21, 22, 23, 24, 26, 26,
+ 27, 28, 29, 30, 32, 32, 32,
+];
+const BACKWARD_LEFT_SLIDE_SQUARES: [usize; 33] = [
+ 1, 3, 3, 4, 5, 7, 7, 8, 9, 11, 11, 13, 13, 14, 15, 16, 17, 19, 19, 20, 21, 22, 23, 24, 25, 27,
+ 27, 28, 29, 30, 31, 32, 32,
+];
+const BACKWARD_RIGHT_SLIDE_SQUARES: [usize; 33] = [
+ 2, 2, 3, 4, 5, 7, 7, 8, 10, 10, 11, 13, 13, 14, 15, 16, 19, 19, 19, 20, 21, 22, 23, 24, 26, 26,
+ 27, 28, 29, 30, 31, 32, 32,
+];
+
+const FORWARD_LEFT_JUMP_SQUARES: [usize; 33] = [
+ 1, 6, 6, 6, 6, 6, 7, 8, 9, 12, 12, 12, 13, 14, 15, 16, 17, 20, 20, 20, 21, 22, 23, 28, 28, 28,
+ 28, 28, 29, 32, 32, 32, 32,
+];
+const FORWARD_RIGHT_JUMP_SQUARES: [usize; 33] = [
+ 2, 2, 3, 6, 6, 6, 7, 12, 12, 12, 12, 12, 13, 14, 15, 18, 18, 18, 19, 20, 21, 22, 23, 26, 26,
+ 26, 27, 28, 29, 32, 32, 32, 32,
+];
+const BACKWARD_LEFT_JUMP_SQUARES: [usize; 33] = [
+ 4, 4, 4, 4, 5, 8, 8, 8, 9, 14, 14, 14, 14, 14, 15, 16, 17, 20, 20, 20, 21, 22, 23, 24, 25, 28,
+ 28, 28, 29, 30, 31, 32, 32,
+];
+const BACKWARD_RIGHT_JUMP_SQUARES: [usize; 33] = [
+ 2, 2, 3, 4, 5, 10, 10, 10, 10, 10, 11, 14, 14, 14, 15, 20, 20, 20, 20, 20, 21, 22, 23, 26, 26,
+ 26, 27, 28, 29, 30, 31, 32, 32,
+];
+
+static SLIDE_ARRAYS: [[usize; 33]; 4] = [
+ FORWARD_LEFT_SLIDE_SQUARES,
+ FORWARD_RIGHT_SLIDE_SQUARES,
+ BACKWARD_LEFT_SLIDE_SQUARES,
+ BACKWARD_RIGHT_SLIDE_SQUARES,
+];
+
+static JUMP_ARRAYS: [[usize; 33]; 4] = [
+ FORWARD_LEFT_JUMP_SQUARES,
+ FORWARD_RIGHT_JUMP_SQUARES,
+ BACKWARD_LEFT_JUMP_SQUARES,
+ BACKWARD_RIGHT_JUMP_SQUARES,
+];
+
+pub struct PossibleMovesIter {
+ possible_moves: PossibleMoves,
+ current_square: usize,
+ current_direction: MoveDirection,
+ movers: u32,
+ squares: &'static [usize; 33],
+}
+
+impl From<PossibleMoves> for PossibleMovesIter {
+ fn from(possible_moves: PossibleMoves) -> Self {
+ Self {
+ possible_moves,
+ current_square: 0,
+ current_direction: MoveDirection::ForwardLeft,
+ movers: possible_moves.forward_left_bits(),
+ squares: unsafe {
+ if possible_moves.can_jump() {
+ JUMP_ARRAYS.get_unchecked(0)
+ } else {
+ SLIDE_ARRAYS.get_unchecked(0)
+ }
+ },
+ }
+ }
+}
+
+impl Iterator for PossibleMovesIter {
+ type Item = Move;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ loop {
+ if self.current_square == 32 {
+ if self.current_direction != MoveDirection::BackwardRight {
+ self.current_square = 0;
+ // safety: only results in undefined variant if equal to backward right
+ // this has already been checked for
+ self.current_direction =
+ unsafe { std::mem::transmute((self.current_direction as u8) + 1) };
+ self.movers = self
+ .possible_moves
+ .get_direction_bits(self.current_direction);
+
+ // safety: the max value of the enum is 3
+ unsafe {
+ self.squares = &*(self.squares as *const [usize; 33]).add(1);
+ }
+ } else {
+ return None;
+ }
+ }
+
+ if (self.movers >> self.current_square) & 1 != 0 {
+ let next_move = Move::new(
+ self.current_square,
+ self.current_direction,
+ self.possible_moves.can_jump(),
+ );
+
+ // safety: self.current_square will never be > 32
+ // squares does not contain such a value
+ unsafe {
+ self.current_square = *self.squares.get_unchecked(self.current_square);
+ }
+
+ return Some(next_move);
+ }
+
+ if self.current_square != 32 {
+ // safety: self.current_square will never be > 32
+ // squares does not contain such a value
+ unsafe {
+ self.current_square = *self.squares.get_unchecked(self.current_square);
+ }
+ }
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (
+ 0,
+ Some(
+ (32 - self.current_square)
+ + 32 * match self.current_direction {
+ MoveDirection::ForwardLeft => 3,
+ MoveDirection::ForwardRight => 2,
+ MoveDirection::BackwardLeft => 1,
+ MoveDirection::BackwardRight => 0,
+ },
+ ),
+ )
+ }
+}
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