More cleanup

1 files changed, 22 insertions, 0 deletions

diff --git a/src/cube_portable.h b/src/cube_portable.h
index 71a7e41..77e803b 100644
--- a/src/cube_portable.h
+++ b/src/cube_portable.h
@@ -22,6 +22,7 @@ _static_inline void compose_corners_inplace(cube_t, cube_t, cube_t *);
 _static_inline cube_t compose_edges(cube_t, cube_t);
 _static_inline cube_t compose_corners(cube_t, cube_t);
 _static_inline cube_t compose(cube_t, cube_t);
+_static_inline cube_t inverse(cube_t);
 
 _static_inline int64_t coord_co(cube_t);
 _static_inline int64_t coord_csep(cube_t);
@@ -133,6 +134,27 @@ compose(cube_t c1, cube_t c2)
         return ret;
 }
 
+cube_t
+inverse(cube_t cube)
+{
+        uint8_t i, piece, orien;
+        cube_t ret;
+
+        for (i = 0; i < 12; i++) {
+                piece = cube.edge[i];
+                orien = piece & _eobit;
+                ret.edge[piece & _pbits] = i | orien;
+        }
+
+        for (i = 0; i < 8; i++) {
+                piece = cube.corner[i];
+                orien = ((piece << 1) | (piece >> 1)) & _cobits2;
+                ret.corner[piece & _pbits] = i | orien;
+        }
+
+        return ret;
+}
+
 _static_inline int64_t
 coord_co(cube_t c)
 {