Use a lookup table for orientation arithmetic.

cubing · Aug 22, 2023 · ac259e3 · ac259e3
1 parent 4364d9a
commit ac259e3
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Showing 2 changed files with 23 additions and 9 deletions.
diff --git a/examples/cpp_port/packed/packed_kpuzzle.rs b/examples/cpp_port/packed/packed_kpuzzle.rs
@@ -12,6 +12,7 @@ pub struct PackedKPuzzleOrbitData {
     pub num_pieces: usize,
     pub num_orientations: u8,
     pub unknown_orientation_value: u8,
+    pub table: [u8; 16],
 }
 
 #[derive(Debug, Clone)]
@@ -22,6 +23,8 @@ pub struct PackedKPuzzleData {
     pub orbit_iteration_info: Vec<PackedKPuzzleOrbitData>,
 }
 
+const X: u8 = 255;
+
 #[derive(Debug, Clone)]
 pub struct PackedKPuzzle {
     // pub data: Arc<PackedKPuzzleData>, // TODO
@@ -48,13 +51,28 @@ impl TryFrom<KPuzzle> for PackedKPuzzle {
                 ),
             })?;
             let unknown_orientation_value = usize_to_u8(2 * orbit_definition.num_orientations);
+            let num_orientations = usize_to_u8(orbit_definition.num_orientations);
+            let table: [u8; 16] = match num_orientations {
+                1 => [0, 0, X, X, X, X, X, X, X, X, X, X, X, X, X, X],
+                2 => [0, 1, 0, X, 4, 4, X, X, X, X, X, X, X, X, X, X],
+                3 => [0, 1, 2, 0, 1, X, 6, 6, 6, X, X, X, X, X, X, X],
+                4 => [0, 1, 2, 3, 0, 1, 2, X, 8, 8, 8, 8, X, X, X, X],
+                5 => [0, 1, 2, 3, 4, 0, 1, 2, 3, X, 10, 10, 10, 10, 10, X],
+                _ => {
+                    return Err(InvalidDefinitionError {
+                        description: "`num_orientations` higher than currently supported"
+                            .to_owned(),
+                    })
+                }
+            };
             orbit_iteration_info.push({
                 PackedKPuzzleOrbitData {
                     name: orbit_name.clone(),
                     num_pieces: orbit_definition.num_pieces,
-                    num_orientations: usize_to_u8(orbit_definition.num_orientations),
+                    num_orientations,
                     bytes_offset,
                     unknown_orientation_value,
+                    table,
                 }
             });
             bytes_offset += orbit_definition.num_pieces * 2;

diff --git a/examples/cpp_port/packed/packed_kstate.rs b/examples/cpp_port/packed/packed_kstate.rs
@@ -30,14 +30,10 @@ impl PackedKState {
                     get_packed_piece_or_permutation!(self.bytes, orbit_info, transformation_idx);
                 let previous_piece_orientation =
                     get_packed_orientation!(self.bytes, orbit_info, transformation_idx);
-                let new_piece_orientation =
-                    if previous_piece_orientation == orbit_info.unknown_orientation_value {
-                        previous_piece_orientation
-                    } else {
-                        (previous_piece_orientation
-                            + get_packed_orientation!(transformation.bytes, orbit_info, i))
-                            % orbit_info.num_orientations
-                    };
+                let new_piece_orientation = orbit_info.table[std::convert::Into::<usize>::into(
+                    previous_piece_orientation
+                        + get_packed_orientation!(transformation.bytes, orbit_info, i),
+                )];
                 set_packed_piece_or_permutation_and_orientation!(
                     bytes,
                     orbit_info,