1 files changed, 797 insertions, 135 deletions

diff --git a/src/cube.c b/src/cube.c
index 92c6713..aae3a6e 100644
--- a/src/cube.c
+++ b/src/cube.c
@@ -1,205 +1,531 @@
-#define CUBE_C
-
 #include "cube.h"
 
-static int where_is_piece(int piece, int *arr, int n);
+/* Local functions ***********************************************************/
 
-void
-compose_centers(Cube *c2, Cube *c1)
+static void             init_inverse();
+static bool             read_invtables_file();
+static bool             write_invtables_file();
+
+/* Tables ********************************************************************/
+
+static uint16_t         eo_invtable_e[POW2TO11][BINOM12ON4*FACTORIAL4];
+static uint16_t         eo_invtable_s[POW2TO11][BINOM12ON4*FACTORIAL4];
+static uint16_t         eo_invtable_m[POW2TO11][BINOM12ON4*FACTORIAL4];
+static uint16_t         co_invtable[POW3TO7][FACTORIAL8];
+static uint16_t         cp_invtable[FACTORIAL8];
+static uint16_t         cpos_invtable[FACTORIAL6];
+
+/* Functions implementation **************************************************/
+
+int
+array_ep_to_epos(int *ep, int *ss)
 {
-        apply_permutation(c2->xp, c1->xp, 6);
+        int epos[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+        int eps[4];
+        int i, j, is;
+
+        for (i = 0, is = 0; i < 12; i++) {
+                for (j = 0; j < 4; j++) {
+                        if (ep[i] == ss[j]) {
+                                eps[is++] = j;
+                                epos[i] = 1;
+                        }
+                }
+        }
+
+        for (i = 0; i < 4; i++)
+                swap(&epos[ss[i]], &epos[i+8]);
+
+        return 24 * subset_to_index(epos, 12, 4) + perm_to_index(eps, 4);
 }
 
-void
-compose_corners(Cube *c2, Cube *c1)
+Cube
+arrays_to_cube(CubeArray *arr, PieceFilter f)
 {
-        apply_permutation(c2->cp, c1->cp, 8);
-        apply_permutation(c2->cp, c1->co, 8);
-        sum_arrays_mod(c2->co, c1->co, 8, 3);
+        Cube ret = {0};
+
+        static int epe_solved[4] = {FR, FL, BL, BR};
+        static int eps_solved[4] = {UL, UR, DL, DR};
+        static int epm_solved[4] = {UF, UB, DF, DB};
+
+        if (f.epose)
+                ret.epose = array_ep_to_epos(arr->ep, epe_solved);
+        if (f.eposs)
+                ret.eposs = array_ep_to_epos(arr->ep, eps_solved);
+        if (f.eposm)
+                ret.eposm = array_ep_to_epos(arr->ep, epm_solved);
+        if (f.eofb)
+                ret.eofb = digit_array_to_int(arr->eofb, 11, 2);
+        if (f.eorl)
+                ret.eorl = digit_array_to_int(arr->eorl, 11, 2);
+        if (f.eoud)
+                ret.eoud = digit_array_to_int(arr->eoud, 11, 2);
+        if (f.cp)
+                ret.cp = perm_to_index(arr->cp, 8);
+        if (f.coud)
+                ret.coud = digit_array_to_int(arr->coud, 7, 3);
+        if (f.corl)
+                ret.corl = digit_array_to_int(arr->corl, 7, 3);
+        if (f.cofb)
+                ret.cofb = digit_array_to_int(arr->cofb, 7, 3);
+        if (f.cpos)
+                ret.cpos = perm_to_index(arr->cpos, 6);
+
+        return ret;
 }
 
-void
-compose_edges(Cube *c2, Cube *c1)
+Cube
+compose_filtered(Cube c2, Cube c1, PieceFilter f)
 {
-        apply_permutation(c2->ep, c1->ep, 12);
-        apply_permutation(c2->ep, c1->eo, 12);
-        sum_arrays_mod(c2->eo, c1->eo, 12, 2);
+        CubeArray *arr = new_cubearray(c2, f);
+        Cube ret;
+
+        ret = move_via_arrays(arr, c1, f);
+        free_cubearray(arr, f);
+
+        return ret;
 }
 
 void
-compose(Cube *c2, Cube *c1)
+cube_to_arrays(Cube cube, CubeArray *arr, PieceFilter f)
 {
-        compose_centers(c2, c1);
-        compose_corners(c2, c1);
-        compose_edges(c2, c1);
+        int i;
+
+        static int epe_solved[4] = {FR, FL, BL, BR};
+        static int eps_solved[4] = {UL, UR, DL, DR};
+        static int epm_solved[4] = {UF, UB, DF, DB};
+
+        if (f.epose || f.eposs || f.eposm)
+                for (i = 0; i < 12; i++)
+                        arr->ep[i] = -1;
+
+        if (f.epose) 
+                epos_to_partial_ep(cube.epose, arr->ep, epe_solved); 
+        if (f.eposs) 
+                epos_to_partial_ep(cube.eposs, arr->ep, eps_solved); 
+        if (f.eposm)
+                epos_to_partial_ep(cube.eposm, arr->ep, epm_solved); 
+        if (f.eofb)
+                int_to_sum_zero_array(cube.eofb, 2, 12, arr->eofb);
+        if (f.eorl)
+                int_to_sum_zero_array(cube.eorl, 2, 12, arr->eorl);
+        if (f.eoud)
+                int_to_sum_zero_array(cube.eoud, 2, 12, arr->eoud);
+        if (f.cp)
+                index_to_perm(cube.cp, 8, arr->cp);
+        if (f.coud)
+                int_to_sum_zero_array(cube.coud, 3, 8, arr->coud);
+        if (f.corl)
+                int_to_sum_zero_array(cube.corl, 3, 8, arr->corl);
+        if (f.cofb)
+                int_to_sum_zero_array(cube.cofb, 3, 8, arr->cofb);
+        if (f.cpos)
+                index_to_perm(cube.cpos, 6, arr->cpos);
 }
 
 void
-copy_cube_centers(Cube *src, Cube *dst)
+epos_to_compatible_ep(int epos, int *ep, int *ss)
 {
-        memcpy(dst->xp, src->xp,  6 * sizeof(int));
+        int i, j, k, other[8];
+        bool flag;
+
+        for (i = 0; i < 12; i++)
+                ep[i] = -1;
+
+        epos_to_partial_ep(epos, ep, ss);
+
+        for (i = 0, j = 0; i < 12; i++) {
+                flag = false;
+                for (k = 0; k < 4; k++)
+                        flag = flag || (i == ss[k]);
+                if (!flag)
+                        other[j++] = i;
+        }
+                
+        for (i = 0, j = 0; i < 12; i++)
+                if (ep[i] == -1)
+                        ep[i] = other[j++];
 }
 
 void
-copy_cube_corners(Cube *src, Cube *dst)
+epos_to_partial_ep(int epos, int *ep, int *ss)
 {
-        memcpy(dst->cp, src->cp,  8 * sizeof(int));
-        memcpy(dst->co, src->co,  8 * sizeof(int));
+        int i, is, eposs[12], eps[4];
+
+        index_to_perm(epos % FACTORIAL4, 4, eps);
+        index_to_subset(epos / FACTORIAL4, 12, 4, eposs);
+
+        for (i = 0; i < 4; i++)
+                swap(&eposs[ss[i]], &eposs[i+8]);
+
+        for (i = 0, is = 0; i < 12; i++)
+                if (eposs[i])
+                        ep[i] = ss[eps[is++]];
 }
 
 void
-copy_cube_edges(Cube *src, Cube *dst)
+fix_eorleoud(CubeArray *arr)
 {
-        memcpy(dst->ep, src->ep, 12 * sizeof(int));
-        memcpy(dst->eo, src->eo, 12 * sizeof(int));
+        int i;
+
+        for (i = 0; i < 12; i++) {
+                if ((edge_slice(i) == 0 && edge_slice(arr->ep[i]) != 0) ||
+                    (edge_slice(i) != 0 && edge_slice(arr->ep[i]) == 0)) {
+                        arr->eorl[i] = 1 - arr->eofb[i];
+                } else {
+                        arr->eorl[i] = arr->eofb[i];
+                }
+
+                if ((edge_slice(i) == 2 && edge_slice(arr->ep[i]) != 2) ||
+                    (edge_slice(i) != 2 && edge_slice(arr->ep[i]) == 2)) {
+                        arr->eoud[i] = 1 - arr->eofb[i];
+                } else {
+                        arr->eoud[i] = arr->eofb[i];
+                }
+        }
 }
 
 void
-copy_cube(Cube *src, Cube *dst)
+fix_cofbcorl(CubeArray *arr)
 {
-        copy_cube_centers(src, dst);
-        copy_cube_corners(src, dst);
-        copy_cube_edges(src, dst);
+        int i;
+
+        for (i = 0; i < 8; i++) {
+                if (i % 2 == arr->cp[i] % 2) {
+                        arr->cofb[i] = arr->coud[i];
+                        arr->corl[i] = arr->coud[i];
+                } else {
+                        if (arr->cp[i] % 2 == 0) {
+                                arr->cofb[i] = (arr->coud[i]+1)%3;
+                                arr->corl[i] = (arr->coud[i]+2)%3;
+                        } else {
+                                arr->cofb[i] = (arr->coud[i]+2)%3;
+                                arr->corl[i] = (arr->coud[i]+1)%3;
+                        }
+                }
+        }
 }
 
-bool
-equal(Cube *c1, Cube *c2)
+Cube
+fourval_to_cube(int eofb, int ep, int coud, int cp)
 {
-        int i;
+        CubeArray *arr;
 
-        for (i = 0; i < 12; i++)
-                if (c1->ep[i] != c2->ep[i] || c1->eo[i] != c2->eo[i])
-                        return false;
+        arr = new_cubearray((Cube){0}, pf_all);
 
-        for (i = 0; i < 8; i++)
-                if (c1->cp[i] != c2->cp[i] || c1->co[i] != c2->co[i])
-                        return false;
+        index_to_perm(ep, 12, arr->ep);
+        index_to_perm(cp,  8, arr->cp);
+        int_to_sum_zero_array(eofb, 2, 12, arr->eofb);
+        int_to_sum_zero_array(coud, 3,  8, arr->coud);
 
-        for (i = 0; i < 6; i++)
-                if (c1->xp[i] != c2->xp[i])
-                        return false;
+        /* fix parity */
+        if (perm_sign(arr->ep, 12) != perm_sign(arr->cp, 8))
+                swap(&(arr->ep[0]), &(arr->ep[1]));
 
-        return true;
+        fix_eorleoud(arr);
+        fix_cofbcorl(arr);
+
+        return arrays_to_cube(arr, pf_all);
 }
 
 void
-invert_cube_centers(Cube *cube)
+free_cubearray(CubeArray *arr, PieceFilter f)
 {
-        int i;
-        Cube aux;
-
-        copy_cube_centers(cube, &aux);
+        if (f.epose || f.eposs || f.eposm)
+                free(arr->ep);
+        if (f.eofb)
+                free(arr->eofb);
+        if (f.eorl)
+                free(arr->eorl);
+        if (f.eoud)
+                free(arr->eoud);
+        if (f.cp)
+                free(arr->cp);
+        if (f.coud)
+                free(arr->coud);
+        if (f.corl)
+                free(arr->corl);
+        if (f.cofb)
+                free(arr->cofb);
+        if (f.cpos)
+                free(arr->cpos);
 
-        for (i = 0; i < 6; i++)
-                cube->xp[aux.xp[i]] = i;
+        free(arr);
 }
 
-void
-invert_cube_corners(Cube *cube)
+Cube
+move_via_arrays(CubeArray *arr, Cube c, PieceFilter f)
 {
-        int i;
-        Cube aux;
+        CubeArray *arrc = new_cubearray(c, f);
+        Cube ret;
 
-        copy_cube_corners(cube, &aux);
+        if (f.epose || f.eposs || f.eposm)
+                apply_permutation(arr->ep, arrc->ep, 12);
 
-        for (i = 0; i < 8; i++) {
-                cube->cp[aux.cp[i]] = i;
-                cube->co[aux.cp[i]] = (3 - aux.co[i]) % 3;
+        if (f.eofb) {
+                apply_permutation(arr->ep, arrc->eofb, 12);
+                sum_arrays_mod(arr->eofb, arrc->eofb, 12, 2);
         }
+
+        if (f.eorl) {
+                apply_permutation(arr->ep, arrc->eorl, 12);
+                sum_arrays_mod(arr->eorl, arrc->eorl, 12, 2);
+        }
+
+        if (f.eoud) {
+                apply_permutation(arr->ep, arrc->eoud, 12);
+                sum_arrays_mod(arr->eoud, arrc->eoud, 12, 2);
+        }
+
+        if (f.cp)
+                apply_permutation(arr->cp, arrc->cp, 8);
+
+        if (f.coud) {
+                apply_permutation(arr->cp, arrc->coud, 8);
+                sum_arrays_mod(arr->coud, arrc->coud, 8, 3);
+        }
+
+        if (f.corl) {
+                apply_permutation(arr->cp, arrc->corl, 8);
+                sum_arrays_mod(arr->corl, arrc->corl, 8, 3);
+        }
+
+        if (f.cofb) {
+                apply_permutation(arr->cp, arrc->cofb, 8);
+                sum_arrays_mod(arr->cofb, arrc->cofb, 8, 3);
+        }
+
+        if (f.cpos)
+                apply_permutation(arr->cpos, arrc->cpos, 6);
+
+        ret = arrays_to_cube(arrc, f);
+        free_cubearray(arrc, f);
+
+        return ret;
 }
 
-void
-invert_cube_edges(Cube *cube)
+CubeArray *
+new_cubearray(Cube cube, PieceFilter f)
 {
-        int i;
-        Cube aux;
+        CubeArray *arr = malloc(sizeof(CubeArray));
 
-        copy_cube_edges(cube, &aux);
+        if (f.epose || f.eposs || f.eposm)
+                arr->ep   = malloc(12 * sizeof(int));
+        if (f.eofb)
+                arr->eofb = malloc(12 * sizeof(int));
+        if (f.eorl)
+                arr->eorl = malloc(12 * sizeof(int));
+        if (f.eoud)
+                arr->eoud = malloc(12 * sizeof(int));
+        if (f.cp)
+                arr->cp   = malloc(8  * sizeof(int));
+        if (f.coud)
+                arr->coud = malloc(8  * sizeof(int));
+        if (f.corl)
+                arr->corl = malloc(8  * sizeof(int));
+        if (f.cofb)
+                arr->cofb = malloc(8  * sizeof(int));
+        if (f.cpos)
+                arr->cpos = malloc(6  * sizeof(int));
 
-        for (i = 0; i < 12; i++) {
-                cube->ep[aux.ep[i]] = i;
-                cube->eo[aux.ep[i]] = aux.eo[i];
+        cube_to_arrays(cube, arr, f);
+
+        return arr;
+}
+
+Cube
+admissible_ep(Cube cube, PieceFilter f)
+{
+        CubeArray *arr = new_cubearray(cube, f);
+        Cube ret;
+        bool used[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+        int i, j;
+
+        for (i = 0; i < 12; i++)
+                if (arr->ep[i] != -1)
+                        used[arr->ep[i]] = true;
+
+        for (i = 0, j = 0; i < 12; i++) {
+                for ( ; j < 11 && used[j]; j++);
+                if (arr->ep[i] == -1)
+                        arr->ep[i] = j++;
         }
+
+        ret = arrays_to_cube(arr, pf_ep);
+        free_cubearray(arr, f);
+
+        return ret;
 }
 
-void
-invert_cube(Cube *cube)
+Cube
+compose(Cube c2, Cube c1)
 {
-        invert_cube_centers(cube);
-        invert_cube_corners(cube);
-        invert_cube_edges(cube);
+        return compose_filtered(c2, c1, pf_all);
+}
+
+int
+edge_slice(Edge e) {
+        if (e < 0 || e > 11)
+                return -1;
+
+        if (e == FR || e == FL || e == BL || e == BR)
+                return 0;
+        if (e == UR || e == UL || e == DR || e == DL)
+                return 1;
+
+        return 2;
 }
 
 bool
-is_admissible(Cube *c) {
-        bool perm;
-        int sign, i;
-        int sum_e, sum_c;
+equal(Cube c1, Cube c2)
+{
+        return c1.eofb  == c2.eofb  &&
+               c1.epose == c2.epose &&
+               c1.eposs == c2.eposs &&
+               c1.eposm == c2.eposm &&
+               c1.coud  == c2.coud  &&
+               c1.cp    == c2.cp    &&
+               c1.cpos  == c2.cpos;
+}
+
+Cube
+inverse_cube(Cube cube)
+{
+        CubeArray inv;
+        Cube ret;
+        int i, ep[12];
 
-        perm = is_perm(c->ep, 12) && is_perm(c->cp, 8) && is_perm(c->xp, 6);
+        for (i = 0; i < 12; i++)
+                ep[i] = where_is_edge(cube, i);
+        inv = (CubeArray){.ep = ep};
+        ret = arrays_to_cube(&inv, pf_ep);
 
-        sign = perm_sign(c->ep,12) + perm_sign(c->cp,8) + perm_sign(c->xp,6);
+        ret.eofb = ((int)eo_invtable_e[cube.eofb][cube.epose]) |
+                   ((int)eo_invtable_m[cube.eofb][cube.eposm]) |
+                   ((int)eo_invtable_s[cube.eofb][cube.eposs]);
+        ret.eorl = ((int)eo_invtable_e[cube.eorl][cube.epose]) |
+                   ((int)eo_invtable_m[cube.eorl][cube.eposm]) |
+                   ((int)eo_invtable_s[cube.eorl][cube.eposs]);
+        ret.eoud = ((int)eo_invtable_e[cube.eoud][cube.epose]) |
+                   ((int)eo_invtable_m[cube.eoud][cube.eposm]) |
+                   ((int)eo_invtable_s[cube.eoud][cube.eposs]);
+        ret.cp   = cp_invtable[cube.cp];
+        ret.cpos = cpos_invtable[cube.cpos];
+        ret.coud = co_invtable[cube.coud][cube.cp];
+        ret.corl = co_invtable[cube.corl][cube.cp];
+        ret.cofb = co_invtable[cube.cofb][cube.cp];
 
-        for (i = 0, sum_e = 0; i < 12; i++)
-                if (c->eo[i] > 1)
-                        return false;
-                else
-                        sum_e += c->eo[i];
+        return ret;
+}
 
-        for (i = 0, sum_c = 0; i < 8; i++)
-                if (c->co[i] > 2)
-                        return false;
-                else
-                        sum_c += c->co[i];
+bool
+is_admissible(Cube cube) {
+
+        /* TODO: this should check consistency of different orientations */
+        /* check also that centers are opposite and admissible */
 
-        return (perm && sign % 2 == 0 && sum_e % 2 == 0 && sum_c % 2 == 0);
+        CubeArray *a = new_cubearray(cube, pf_all);
+        int parity;
+        bool perm;
+
+        perm   = is_perm(a->ep,  12)  &&
+                 is_perm(a->cp,   8)  &&
+                 is_perm(a->cpos, 6);
+        parity = perm_sign(a->ep,  12) +
+                 perm_sign(a->cp,   8) +
+                 perm_sign(a->cpos, 6);
+
+        free_cubearray(a, pf_all);
+
+        return perm && parity % 2 == 0;
 }
 
 bool
-is_solved(Cube *cube)
+is_solved(Cube cube)
 {
-        Cube solved_cube;
-        make_solved(&solved_cube);
-
-        return equal(cube, &solved_cube);
+        return equal(cube, (Cube){0});
 }
 
-void
-make_solved_centers(Cube *cube)
+bool
+is_block_solved(Cube cube, Block block)
 {
-        static int sorted[6] = {0, 1, 2, 3, 4, 5};
+        int i;
+
+        for (i = 0; i < 12; i++)
+                if (block.edge[i] && !is_solved_edge(cube, i))
+                        return false;
+        for (i = 0; i < 8; i++)
+                if (block.corner[i] && !is_solved_corner(cube, i))
+                        return false;
+        for (i = 0; i < 6; i++)
+                if (block.center[i] && !is_solved_center(cube, i))
+                        return false;
 
-        memcpy(cube->xp, sorted,  6 * sizeof(int));
+        return true;
 }
 
-void
-make_solved_corners(Cube *cube)
+bool
+is_solved_center(Cube cube, Center c)
 {
-        static int sorted[8] = {0, 1, 2, 3, 4, 5, 6, 7};
-
-        memcpy(cube->cp, sorted,  8 * sizeof(int));
-        memset(cube->co, 0,       8 * sizeof(int));
+        return what_center_at(cube, c) == c;
 }
 
-void
-make_solved_edges(Cube *cube)
+bool
+is_solved_corner(Cube cube, Corner c)
 {
-        static int sorted[12] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
+        return what_corner_at(cube, c) == c &&
+               what_orientation_corner(cube.coud, c);
+}
 
-        memcpy(cube->ep, sorted, 12 * sizeof(int));
-        memset(cube->eo, 0,      12 * sizeof(int));
+bool
+is_solved_edge(Cube cube, Edge e)
+{
+        return what_edge_at(cube, e) == e &&
+               what_orientation_edge(cube.eofb, e);
 }
 
-void
-make_solved(Cube *cube)
+int
+piece_orientation(Cube cube, int piece, char *orientation)
 {
-        make_solved_centers(cube);
-        make_solved_corners(cube);
-        make_solved_edges(cube);
+        int arr[12], n, b, x;
+
+        if (!strcmp(orientation, "eofb")) {
+                x = cube.eofb;
+                n = 12;
+                b = 2;
+        } else if (!strcmp(orientation, "eorl")) {
+                x = cube.eorl;
+                n = 12;
+                b = 2;
+        } else if (!strcmp(orientation, "eoud")) {
+                x = cube.eoud;
+                n = 12;
+                b = 2;
+        } else if (!strcmp(orientation, "coud")) {
+                x = cube.coud;
+                n = 8;
+                b = 3;
+        } else if (!strcmp(orientation, "corl")) {
+                x = cube.corl;
+                n = 8;
+                b = 3;
+        } else if (!strcmp(orientation, "cofb")) {
+                x = cube.cofb;
+                n = 8;
+                b = 3;
+        } else {
+                return -1;
+        }
+
+        int_to_sum_zero_array(x, b, n, arr);
+        if (piece < n)
+                return arr[piece];
+
+        return -1;
 }
 
 void
-print_cube(Cube *cube)
+print_cube(Cube cube)
 {
         static char edge_string[12][7] = {
                 [UF] = "UF", [UL] = "UL", [UB] = "UB", [UR] = "UR",
@@ -219,52 +545,388 @@ print_cube(Cube *cube)
         };
 
         for (int i = 0; i < 12; i++)
-                printf(" %s ", edge_string[cube->ep[i]]);
+                printf(" %s ", edge_string[what_edge_at(cube, i)]);
         printf("\n");
 
         for (int i = 0; i < 12; i++)
-                printf("  %" PRIu8 " ", cube->eo[i]);
+                printf("  %d ", what_orientation_edge(cube.eofb, i));
         printf("\n");
 
         for (int i = 0; i < 8; i++)
-                printf("%s ", corner_string[cube->cp[i]]);
+                printf("%s ", corner_string[what_corner_at(cube, i)]);
         printf("\n");
 
         for (int i = 0; i < 8; i++)
-                printf("  %" PRIu8 " ", cube->co[i]);
+                printf("  %d ", what_orientation_corner(cube.coud, i));
         printf("\n");
 
         for (int i = 0; i < 6; i++)
-                printf("  %s ", center_string[cube->xp[i]]);
+                printf("  %s ", center_string[what_center_at(cube, i)]);
         printf("\n");
 }
 
-int
-where_is_center(Center x, Cube *c)
+Center
+what_center_at(Cube cube, Center c)
+{
+        static bool initialized = false;
+        static Center aux[FACTORIAL6][6];
+        static int i;
+        static unsigned int ui;
+        static CubeArray *arr;
+
+        if (!initialized) {
+                for (ui = 0; ui < FACTORIAL6; ui++) {
+                        arr = new_cubearray((Cube){.cpos = ui}, pf_cpos);
+                        for (i = 0; i < 6; i++)
+                                aux[ui][i] = arr->cpos[i];
+                        free_cubearray(arr, pf_cpos);
+                }
+
+                initialized = true;
+        }
+
+        return aux[cube.cpos][c];
+}
+
+Corner
+what_corner_at(Cube cube, Corner c)
+{
+        int i;
+        unsigned int ui;
+        CubeArray *arr;
+
+        static bool initialized = false;
+        static Corner aux[FACTORIAL8][8];
+
+        if (!initialized) {
+                for (ui = 0; ui < FACTORIAL8; ui++) {
+                        arr = new_cubearray((Cube){.cp = ui}, pf_cp);
+                        for (i = 0; i < 8; i++)
+                                aux[ui][i] = arr->cp[i];
+                        free_cubearray(arr, pf_cp);
+                }
+
+                initialized = true;
+        }
+
+        return aux[cube.cp][c];
+}
+
+Edge
+what_edge_at(Cube cube, Edge e)
 {
-        return where_is_piece(x, c->xp, 6);
+        Edge ret;
+        CubeArray *arr = new_cubearray(cube, pf_ep);
+
+        ret = arr->ep[e];
+
+        free_cubearray(arr, pf_ep);
+        return ret;
 }
 
 int
-where_is_corner(Corner k, Cube *c)
+what_orientation_corner(int co, Corner c)
 {
-        return where_is_piece(k, c->cp, 8);
+        static bool initialized = false;
+        static int auxlast[POW3TO7];
+        static int auxarr[8];
+        static unsigned int ui;
+
+        if (!initialized) {
+                for (ui = 0; ui < POW3TO7; ui++) {
+                        int_to_sum_zero_array(ui, 3, 8, auxarr);
+                        auxlast[ui] = auxarr[7];
+                }
+
+                initialized = true;
+        }
+
+        if (c < 7)
+                return (co / powint(3, c)) % 3;
+        else
+                return auxlast[co];
 }
 
 int
-where_is_edge(Edge e, Cube *c)
+what_orientation_edge(int eo, Edge e)
+{
+        static bool initialized = false;
+        static int auxlast[POW2TO11];
+        static int auxarr[12];
+        static unsigned int ui;
+
+        if (!initialized) {
+                for (ui = 0; ui < POW2TO11; ui++) {
+                        int_to_sum_zero_array(ui, 2, 12, auxarr);
+                        auxlast[ui] = auxarr[11];
+                }
+
+                initialized = true;
+        }
+
+        if (e < 11)
+                return (eo & (1 << e)) ? 1 : 0;
+        else
+                return auxlast[eo];
+}
+
+Center
+where_is_center(Cube cube, Center c)
 {
-        return where_is_piece(e, c->ep, 12);
+        static bool initialized = false;
+        static Center aux[FACTORIAL6][6];
+        static int i;
+        static unsigned int ui;
+        static CubeArray *arr;
+
+        if (!initialized) {
+                for (ui = 0; ui < FACTORIAL6; ui++) {
+                        arr = new_cubearray((Cube){.cpos = ui}, pf_cpos);
+                        for (i = 0; i < 6; i++)
+                                aux[ui][arr->cpos[i]] = i;
+                        free_cubearray(arr, pf_cpos);
+                }
+
+                initialized = true;
+        }
+
+        return aux[cube.cpos][c];
 }
 
-static int
-where_is_piece(int piece, int *arr, int n)
+Corner
+where_is_corner(Cube cube, Corner c)
 {
-        int i;
+        static bool initialized = false;
+        static Corner aux[FACTORIAL8][8];
+        static int i;
+        static unsigned int ui;
+        static CubeArray *arr;
 
-        for (i = 0; i < n; i++)
-                if (arr[i] == piece)
-                        return i;
+        if (!initialized) {
+                for (ui = 0; ui < FACTORIAL8; ui++) {
+                        arr = new_cubearray((Cube){.cp = ui}, pf_cp);
+                        for (i = 0; i < 8; i++)
+                                aux[ui][arr->cp[i]] = i;
+                        free_cubearray(arr, pf_cp);
+                }
 
-        return -1;
+                initialized = true;
+        }
+        return aux[cube.cp][c];
+}
+
+Edge
+where_is_edge(Cube c, Edge e)
+{
+        int r0, r1, r2;
+
+        static bool initialized = false;
+        static int aux[3][BINOM12ON4*FACTORIAL4][12];
+        static int i, j;
+        static unsigned int ui;
+        static CubeArray *arr;
+
+        if (!initialized) {
+                for (ui = 0; ui < BINOM12ON4*FACTORIAL4; ui++) {
+                        for (i = 0; i < 3; i++)
+                                for (j = 0; j < 12; j++)
+                                        aux[i][ui][j] = -1;
+                                
+                        arr = new_cubearray((Cube){.epose = ui}, pf_e);
+                        for (i = 0; i < 12; i++)
+                                if (edge_slice(arr->ep[i]) == 0)
+                                        aux[0][ui][arr->ep[i]] = i;
+                        free_cubearray(arr, pf_e);
+
+                        arr = new_cubearray((Cube){.eposs = ui}, pf_s);
+                        for (i = 0; i < 12; i++)
+                                if (edge_slice(arr->ep[i]) == 1)
+                                        aux[1][ui][arr->ep[i]] = i;
+                        free_cubearray(arr, pf_s);
+
+                        arr = new_cubearray((Cube){.eposm = ui}, pf_m);
+                        for (i = 0; i < 12; i++)
+                                if (edge_slice(arr->ep[i]) == 2)
+                                        aux[2][ui][arr->ep[i]] = i;
+                        free_cubearray(arr, pf_m);
+                }
+
+                initialized = true;
+        }
+
+        r0 = aux[0][c.epose][e];
+        r1 = aux[1][c.eposs][e];
+        r2 = aux[2][c.eposm][e];
+        return MAX(r0, MAX(r1, r2));
+}
+
+static bool
+read_invtables_file()
+{
+        init_env();
+
+        FILE *f;
+        char fname[strlen(tabledir)+20];
+        int b;
+        unsigned int ui, meeo, meco, mecp, mecpos;
+        bool r;
+
+        strcpy(fname, tabledir);
+        strcat(fname, "/invtables");
+
+        if ((f = fopen(fname, "rb")) == NULL)
+                return false;
+
+        b = sizeof(uint16_t);
+        r = true;
+        meeo = BINOM12ON4*FACTORIAL4;
+        meco = FACTORIAL8;
+        mecp = FACTORIAL8;
+        mecpos = FACTORIAL6;
+
+        for (ui = 0; ui < POW2TO11; ui++) {
+                r = r && fread(eo_invtable_e[ui], b, meeo, f) == meeo;
+                r = r && fread(eo_invtable_m[ui], b, meeo, f) == meeo;
+                r = r && fread(eo_invtable_s[ui], b, meeo, f) == meeo;
+        }
+
+        for (ui = 0; ui < POW3TO7; ui++) {
+                r = r && fread(co_invtable[ui], b, meco, f) == meco;
+        }
+
+        r = r && fread(cp_invtable,   b, mecp,   f) == mecp;
+        r = r && fread(cpos_invtable, b, mecpos, f) == mecpos;
+
+        fclose(f);
+        return r;
+}
+
+static bool
+write_invtables_file()
+{
+        init_env();
+
+        FILE *f;
+        char fname[strlen(tabledir)+20];
+        unsigned int ui, meeo, meco, mecp, mecpos;
+        int b;
+        bool r;
+
+        strcpy(fname, tabledir);
+        strcat(fname, "/invtables");
+
+        if ((f = fopen(fname, "wb")) == NULL)
+                return false;
+
+        b = sizeof(uint16_t);
+        r = true;
+        meeo = BINOM12ON4*FACTORIAL4;
+        meco = FACTORIAL8;
+        mecp = FACTORIAL8;
+        mecpos = FACTORIAL6;
+
+        for (ui = 0; ui < POW2TO11; ui++) {
+                r = r && fwrite(eo_invtable_e[ui], b, meeo, f) == meeo;
+                r = r && fwrite(eo_invtable_m[ui], b, meeo, f) == meeo;
+                r = r && fwrite(eo_invtable_s[ui], b, meeo, f) == meeo;
+        }
+
+        for (ui = 0; ui < POW3TO7; ui++) {
+                r = r && fwrite(co_invtable[ui], b, meco, f) == meco;
+        }
+
+        r = r && fwrite(cp_invtable,   b, mecp,   f) == mecp;
+        r = r && fwrite(cpos_invtable, b, mecpos, f) == mecpos;
+
+        fclose(f);
+        return r;
+}
+
+void
+init_inverse()
+{
+        static bool initialized = false;
+        if (initialized)
+                return;
+        initialized = true;
+
+        if (read_invtables_file())
+                return;
+
+        fprintf(stderr, "Cannot load invtables, generating it\n");
+
+        CubeArray *aux, *inv;
+        Cube c;
+        int i, j, eoaux[12], eoinv[12];
+        unsigned int ui, uj;
+
+        aux = new_cubearray((Cube){0}, pf_all);
+        inv = new_cubearray((Cube){0}, pf_all);
+
+        for (ui = 0; ui < POW2TO11; ui++) {
+                int_to_sum_zero_array(ui, 2, 12, eoaux);
+                for (uj = 0; uj < BINOM12ON4*FACTORIAL4; uj++) {
+                        for (j = 0; j < 12; j++)
+                                eoinv[j] = 0;
+                        c = (Cube){.epose = uj, .eposm = 0, .eposs = 0};
+                        eoinv[FR] = eoaux[where_is_edge(c, FR)];
+                        eoinv[FL] = eoaux[where_is_edge(c, FL)];
+                        eoinv[BL] = eoaux[where_is_edge(c, BL)];
+                        eoinv[BR] = eoaux[where_is_edge(c, BR)];
+                        eo_invtable_e[ui][uj] = digit_array_to_int(eoinv,11,2);
+ 
+                        for (j = 0; j < 12; j++)
+                                eoinv[j] = 0;
+                        c = (Cube){.epose = 0, .eposm = uj, .eposs = 0};
+                        eoinv[UF] = eoaux[where_is_edge(c, UF)];
+                        eoinv[UB] = eoaux[where_is_edge(c, UB)];
+                        eoinv[DF] = eoaux[where_is_edge(c, DF)];
+                        eoinv[DB] = eoaux[where_is_edge(c, DB)];
+                        eo_invtable_m[ui][uj] = digit_array_to_int(eoinv,11,2);
+ 
+                        for (j = 0; j < 12; j++)
+                                eoinv[j] = 0;
+                        c = (Cube){.epose = 0, .eposm = 0, .eposs = uj};
+                        eoinv[UL] = eoaux[where_is_edge(c, UL)];
+                        eoinv[UR] = eoaux[where_is_edge(c, UR)];
+                        eoinv[DL] = eoaux[where_is_edge(c, DL)];
+                        eoinv[DR] = eoaux[where_is_edge(c, DR)];
+                        eo_invtable_s[ui][uj] = digit_array_to_int(eoinv,11,2);
+                }
+        }
+
+        for (ui = 0; ui < FACTORIAL8; ui++) {
+                cube_to_arrays((Cube){.cp = ui}, aux, pf_cp);
+                for (i = 0; i < 8; i++)
+                        inv->cp[aux->cp[i]] = i;
+                cp_invtable[ui] = (uint16_t)arrays_to_cube(inv, pf_cp).cp;
+
+                for (uj = 0; uj < POW3TO7; uj++) {
+                        cube_to_arrays((Cube){.coud = uj}, aux, pf_coud);
+                        for (i = 0; i < 8; i++)
+                                inv->coud[aux->cp[i]] = (3-aux->coud[i])%3;
+                        co_invtable[uj][ui] =
+                            (uint16_t)arrays_to_cube(inv, pf_coud).coud;
+                }
+        }
+        
+        for (ui = 0; ui < FACTORIAL6; ui++) {
+                cube_to_arrays((Cube){.cpos = ui}, aux, pf_cpos);
+                for (i = 0; i < 6; i++)
+                        inv->cpos[aux->cpos[i]] = i;
+                cpos_invtable[ui] =
+                    (uint16_t)arrays_to_cube(inv, pf_cpos).cpos;
+        }
+
+        free_cubearray(aux, pf_all);
+        free_cubearray(inv, pf_all);
+
+        if (!write_invtables_file())
+                fprintf(stderr, "Error writing invtables\n");
+}
+
+void
+init_cube()
+{
+        init_inverse();
 }