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#define _move(M, c) compose(c, _move_cube_ ## M)
#define _premove(M, c) compose(_move_cube_ ## M, c)
_static cube_t solvedcube(void);
_static bool isconsistent(cube_t);
_static bool issolvable(cube_t);
_static bool issolved(cube_t);
_static bool iserror(cube_t);
_static cube_t applymoves(cube_t, const char *);
_static cube_t applytrans(cube_t, const char *);
_static cube_t frommoves(const char *);
_static int permsign(uint8_t *, int);
_static cube_t move(cube_t, uint8_t);
_static cube_t transform_edges(cube_t, uint8_t);
_static cube_t transform_corners(cube_t, uint8_t);
_static cube_t transform(cube_t, uint8_t);
_static cube_t
solvedcube(void)
{
return solved;
}
_static bool
isconsistent(cube_t cube)
{
uint8_t i, p, e, piece, corner[8], edge[12];
bool found[12];
pieces(&cube, corner, edge);
for (i = 0; i < 12; i++)
found[i] = false;
for (i = 0; i < 12; i++) {
piece = edge[i];
p = piece & _pbits;
e = piece & _eobit;
if (p >= 12)
goto inconsistent_ep;
if (e != 0 && e != _eobit)
goto inconsistent_eo;
found[p] = true;
}
for (i = 0; i < 12; i++)
if (!found[i])
goto inconsistent_ep;
for (i = 0; i < 8; i++)
found[i] = false;
for (i = 0; i < 8; i++) {
piece = corner[i];
p = piece & _pbits;
e = piece & _cobits;
if (p >= 8)
goto inconsistent_cp;
if (e != 0 && e != _ctwist_cw && e != _ctwist_ccw)
goto inconsistent_co;
found[p] = true;
}
for (i = 0; i < 8; i++)
if (!found[i])
goto inconsistent_co;
return true;
inconsistent_ep:
_log("Inconsistent EP\n");
return false;
inconsistent_cp:
_log("Inconsistent CP\n");
return false;
inconsistent_eo:
_log("Inconsistent EO\n");
return false;
inconsistent_co:
_log("Inconsistent CO\n");
return false;
}
_static bool
issolvable(cube_t cube)
{
uint8_t i, eo, co, piece, edge[12], corner[8], ep[12], cp[8];
DBG_ASSERT(isconsistent(cube), false,
"issolvable: cube is inconsistent\n");
pieces(&cube, corner, edge);
for (i = 0; i < 12; i++)
ep[i] = edge[i] & _pbits;
for (i = 0; i < 8; i++)
cp[i] = corner[i] & _pbits;
if (permsign(ep, 12) != permsign(cp, 8))
goto issolvable_parity;
eo = 0;
for (i = 0; i < 12; i++) {
piece = edge[i];
eo += (piece & _eobit) >> _eoshift;
}
if (eo % 2 != 0)
goto issolvable_eo;
co = 0;
for (i = 0; i < 8; i++) {
piece = corner[i];
co += (piece & _cobits) >> _coshift;
}
if (co % 3 != 0)
goto issolvable_co;
return true;
issolvable_parity:
_log("EP and CP parities are different\n");
return false;
issolvable_eo:
_log("Odd number of flipped edges\n");
return false;
issolvable_co:
_log("Sum of corner orientation is not multiple of 3\n");
return false;
}
bool
issolved(cube_t cube)
{
return equal(cube, solved);
}
bool
iserror(cube_t cube)
{
return equal(cube, zero);
}
_static cube_t
applymoves(cube_t cube, const char *buf)
{
uint8_t r, m;
const char *b;
DBG_ASSERT(isconsistent(cube), zero,
"move error: inconsistent cube\n");
for (b = buf; *b != '\0'; b++) {
while (*b == ' ' || *b == '\t' || *b == '\n')
b++;
if (*b == '\0')
goto applymoves_finish;
if ((r = readmove(*b)) == _error)
goto applymoves_error;
if ((m = readmodifier(*(b+1))) != 0)
b++;
cube = move(cube, r + m);
}
applymoves_finish:
return cube;
applymoves_error:
_log("applymoves error\n");
return zero;
}
_static cube_t
frommoves(const char *buf)
{
return applymoves(solved, buf);
}
_static cube_t
applytrans(cube_t cube, const char *buf)
{
uint8_t t;
DBG_ASSERT(isconsistent(cube), zero,
"transformation error: inconsistent cube\n");
t = readtrans(buf);
return transform(cube, t);
}
_static int
permsign(uint8_t *a, int n)
{
int i, j;
uint8_t ret = 0;
for (i = 0; i < n; i++)
for (j = i+1; j < n; j++)
ret += a[i] > a[j] ? 1 : 0;
return ret % 2;
}
_static cube_t
move(cube_t c, uint8_t m)
{
switch (m) {
case _move_U:
return _move(U, c);
case _move_U2:
return _move(U2, c);
case _move_U3:
return _move(U3, c);
case _move_D:
return _move(D, c);
case _move_D2:
return _move(D2, c);
case _move_D3:
return _move(D3, c);
case _move_R:
return _move(R, c);
case _move_R2:
return _move(R2, c);
case _move_R3:
return _move(R3, c);
case _move_L:
return _move(L, c);
case _move_L2:
return _move(L2, c);
case _move_L3:
return _move(L3, c);
case _move_F:
return _move(F, c);
case _move_F2:
return _move(F2, c);
case _move_F3:
return _move(F3, c);
case _move_B:
return _move(B, c);
case _move_B2:
return _move(B2, c);
case _move_B3:
return _move(B3, c);
default:
_log("move error, unknown move\n");
return zero;
}
}
/*
TODO transform is now relegated to a separated file because it is too long.
It would be nice to make it shorter without loosing performance.
*/
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