path: root/src/cube_routines.h

#define _move(M, c) compose_fast(c, _move_cube_ ## M)
#define _premove(M, c) compose_fast(_move_cube_ ## M, c)
#define _trans_rotation(T, c) \
	compose_fast(compose_fast(_trans_cube_ ## T, c), \
	_trans_cube_ ## T ## _inverse)
#define _trans_mirrored(T, c) \
	invertco_fast(compose_fast(compose_fast(_trans_cube_ ## T, c), \
	_trans_cube_ ## T ## _inverse))

_static int permsign(uint8_t *, int);
_static uint8_t readco(const char *);
_static uint8_t readcp(const char *);
_static uint8_t readeo(const char *);
_static uint8_t readep(const char *);
_static cube_t readcube_H48(const char *);
_static uint8_t readpiece_LST(const char **);
_static cube_t readcube_LST(const char *);
_static int writepiece_LST(uint8_t, char *);
_static void writecube_H48(cube_t, char *);
_static void writecube_LST(cube_t, char *);
_static uint8_t readmove(char);
_static uint8_t readmodifier(char);
_static uint8_t readtrans(const char *);
_static int writemoves(uint8_t *, int, char *);
_static void writetrans(uint8_t, char *);
_static cube_fast_t move(cube_fast_t, uint8_t);
_static cube_fast_t transform(cube_fast_t, uint8_t);

cube_t
solvedcube(void)
{
	return solved;
}

bool
isconsistent(cube_t cube)
{
	uint8_t i, p, e, piece;
	bool found[12];

	for (i = 0; i < 12; i++)
		found[i] = false;
	for (i = 0; i < 12; i++) {
		piece = cube.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 = cube.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:
	DBG_LOG("Inconsistent EP\n");
	return false;
inconsistent_cp:
	DBG_LOG("Inconsistent CP\n");
	return false;
inconsistent_eo:
	DBG_LOG("Inconsistent EO\n");
	return false;
inconsistent_co:
	DBG_LOG("Inconsistent CO\n");
	return false;
}

bool
issolvable(cube_t cube)
{
	uint8_t i, eo, co, piece, edges[12], corners[8];

	DBG_ASSERT(isconsistent(cube), false,
	    "issolvable: cube is inconsistent\n");

	for (i = 0; i < 12; i++)
		edges[i] = cube.edge[i] & _pbits;
	for (i = 0; i < 8; i++)
		corners[i] = cube.corner[i] & _pbits;

	if (permsign(edges, 12) != permsign(corners, 8))
		goto issolvable_parity;

	eo = 0;
	for (i = 0; i < 12; i++) {
		piece = cube.edge[i];
		eo += (piece & _eobit) >> _eoshift;
	}
	if (eo % 2 != 0)
		goto issolvable_eo;

	co = 0;
	for (i = 0; i < 8; i++) {
		piece = cube.corner[i];
		co += (piece & _cobits) >> _coshift;
	}
	if (co % 3 != 0)
		goto issolvable_co;

	return true;

issolvable_parity:
	DBG_LOG("EP and CP parities are different\n");
	return false;
issolvable_eo:
	DBG_LOG("Odd number of flipped edges\n");
	return false;
issolvable_co:
	DBG_LOG("Sum of corner orientation is not multiple of 3\n");
	return false;
}

bool
issolved(cube_t cube)
{
	return equal(cube, solved);
}

bool
equal(cube_t c1, cube_t c2)
{
	int i;
	bool ret;

	ret = true;
	for (i = 0; i < 8; i++)
		ret = ret && c1.corner[i] == c2.corner[i];
	for (i = 0; i < 12; i++)
		ret = ret && c1.edge[i] == c2.edge[i];

	return ret;
}

bool
iserror(cube_t cube)
{
	return equal(cube, zero);
}

cube_t
compose(cube_t c1, cube_t c2)
{
	DBG_ASSERT(isconsistent(c1) && isconsistent(c2),
	    zero, "compose error: inconsistent cube\n")

	return fasttocube(compose_fast(cubetofast(c1), cubetofast(c2)));
}

cube_t
inverse(cube_t cube)
{
	cube_t ret;
	uint8_t i, piece, orien;

	DBG_ASSERT(isconsistent(cube), zero,
	    "inverse error: inconsistent cube\n");

	ret = zero;

	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;
}

cube_t
applymoves(cube_t cube, const char *buf)
{
	cube_fast_t fast;
	uint8_t r, m;
	const char *b;

	DBG_ASSERT(isconsistent(cube), zero,
	    "move error: inconsistent cube\n");

	fast = cubetofast(cube);

	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++;
		fast = move(fast, r + m);
	}

applymoves_finish:
	return fasttocube(fast);

applymoves_error:
	DBG_LOG("applymoves error\n");
	return zero;
}

cube_t
applytrans(cube_t cube, const char *buf)
{
	cube_fast_t fast;
	uint8_t t;

	DBG_ASSERT(isconsistent(cube), zero,
	    "transformation error: inconsistent cube\n");

	t = readtrans(buf);
	fast = cubetofast(cube);
	fast = transform(fast, t);

	return fasttocube(fast);
}

cube_t
readcube(const char *format, const char *buf)
{
	cube_t cube;

	if (!strcmp(format, "H48")) {
		cube = readcube_H48(buf);
	} else if (!strcmp(format, "LST")) {
		cube = readcube_LST(buf);
	} else {
		DBG_LOG("Cannot read cube in the given format\n");
		cube = zero;
	}

	return cube;
}

void
writecube(const char *format, cube_t cube, char *buf)
{
	char *errormsg;
	size_t len;

	if (!isconsistent(cube)) {
		errormsg = "ERROR: cannot write inconsistent cube";
		goto writecube_error;
	}

	if (!strcmp(format, "H48")) {
		writecube_H48(cube, buf);
	} else if (!strcmp(format, "LST")) {
		writecube_LST(cube, buf);
	} else {
		errormsg = "ERROR: cannot write cube in the given format";
		goto writecube_error;
	}

	return;

writecube_error:
	DBG_LOG("writecube error, see stdout for details\n");
	len = strlen(errormsg);
	memcpy(buf, errormsg, len);
	buf[len] = '\n';
	buf[len+1] = '\0';
}

_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 uint8_t
readco(const char *str)
{
	if (*str == '0')
		return 0;
	if (*str == '1')
		return _ctwist_cw;
	if (*str == '2')
		return _ctwist_ccw;

	DBG_LOG("Error reading CO\n");
	return _error;
}

_static uint8_t
readcp(const char *str)
{
	uint8_t c;

	for (c = 0; c < 8; c++)
		if (!strncmp(str, cornerstr[c], 3) ||
		    !strncmp(str, cornerstralt[c], 3))
			return c;

	DBG_LOG("Error reading CP\n");
	return _error;
}

_static uint8_t
readeo(const char *str)
{
	if (*str == '0')
		return 0;
	if (*str == '1')
		return _eflip;

	DBG_LOG("Error reading EO\n");
	return _error;
}

_static uint8_t
readep(const char *str)
{
	uint8_t e;

	for (e = 0; e < 12; e++)
		if (!strncmp(str, edgestr[e], 2))
			return e;

	DBG_LOG("Error reading EP\n");
	return _error;
}

_static cube_t
readcube_H48(const char *buf)
{
	int i;
	uint8_t piece, orient;
	cube_t ret = {0};
	const char *b;
	
	b = buf;

	for (i = 0; i < 12; i++) {
		while (*b == ' ' || *b == '\t' || *b == '\n')
			b++;
		if ((piece = readep(b)) == _error)
			return zero;
		b += 2;
		if ((orient = readeo(b)) == _error)
			return zero;
		b++;
		ret.edge[i] = piece | orient;
	}
	for (i = 0; i < 8; i++) {
		while (*b == ' ' || *b == '\t' || *b == '\n')
			b++;
		if ((piece = readcp(b)) == _error)
			return zero;
		b += 3;
		if ((orient = readco(b)) == _error)
			return zero;
		b++;
		ret.corner[i] = piece | orient;
	}

	return ret;
}

_static uint8_t
readpiece_LST(const char **b)
{
	uint8_t ret;
	bool read;

	while (**b == ',' || **b == ' ' || **b == '\t' || **b == '\n')
		(*b)++;

	for (ret = 0, read = false; **b >= '0' && **b <= '9'; (*b)++) {
		read = true;
		ret = ret * 10 + (**b) - '0';
	}

	return read ? ret : _error;
}

_static cube_t
readcube_LST(const char *buf)
{
	int i;
	cube_t ret = {0};

	for (i = 0; i < 8; i++)
		ret.corner[i] = readpiece_LST(&buf);

	for (i = 0; i < 12; i++)
		ret.edge[i] = readpiece_LST(&buf);

	return ret;
}

_static int
writepiece_LST(uint8_t piece, char *buf)
{
	char digits[3];
	int i, len = 0;

	while (piece != 0) {
		digits[len++] = (piece % 10) + '0';
		piece /= 10;
	}

	if (len == 0)
		digits[len++] = '0';

	for (i = 0; i < len; i++)
		buf[i] = digits[len-i-1];

	buf[len] = ',';
	buf[len+1] = ' ';

	return len+2;
}

_static void
writecube_H48(cube_t cube, char *buf)
{
	uint8_t piece, perm, orient;
	int i;

	for (i = 0; i < 12; i++) {
		piece = cube.edge[i];
		perm = piece & _pbits;
		orient = (piece & _eobit) >> _eoshift;
		buf[4*i    ] = edgestr[perm][0];
		buf[4*i + 1] = edgestr[perm][1];
		buf[4*i + 2] = orient + '0';
		buf[4*i + 3] = ' ';
	}
	for (i = 0; i < 8; i++) {
		piece = cube.corner[i];
		perm = piece & _pbits;
		orient = (piece & _cobits) >> _coshift;
		buf[48 + 5*i    ] = cornerstr[perm][0];
		buf[48 + 5*i + 1] = cornerstr[perm][1];
		buf[48 + 5*i + 2] = cornerstr[perm][2];
		buf[48 + 5*i + 3] = orient + '0';
		buf[48 + 5*i + 4] = ' ';
	}

	buf[48+39] = '\0';
}

_static void
writecube_LST(cube_t cube, char *buf)
{
	int i, ptr;
	uint8_t piece;

	ptr = 0;

	for (i = 0; i < 8; i++) {
		piece = cube.corner[i];
		ptr += writepiece_LST(piece, buf + ptr);
	}

	for (i = 0; i < 12; i++) {
		piece = cube.edge[i];
		ptr += writepiece_LST(piece, buf + ptr);
	}

	*(buf+ptr-2) = 0;
}

_static uint8_t
readmove(char c)
{
	switch (c) {
	case 'U':
		return _move_U;
	case 'D':
		return _move_D;
	case 'R':
		return _move_R;
	case 'L':
		return _move_L;
	case 'F':
		return _move_F;
	case 'B':
		return _move_B;
	default:
		return _error;
	}
}

_static uint8_t
readmodifier(char c)
{
	switch (c) {
	case '1': /* Fallthrough */
	case '2': /* Fallthrough */
	case '3':
		return c - '0' - 1;
	case '\'':
		return 2;
	default:
		return 0;
	}
}

_static uint8_t
readtrans(const char *buf)
{
	uint8_t t;

	for (t = 0; t < 48; t++)
		if (!strncmp(buf, transstr[t], 11))
			return t;

	DBG_LOG("readtrans error\n");
	return _error;
}

_static int
writemoves(uint8_t *m, int n, char *buf)
{
	int i;
	size_t len;
	const char *s;
	char *b;

	for (i = 0, b = buf; i < n; i++, b++) {
		s = movestr[m[i]];
		len = strlen(s);
		memcpy(b, s, len);
		b += len;	
		*b = ' ';
	}

	if (b != buf)
		b--; /* Remove last space */
	*b = '\0';

	return b - buf;
}

_static void
writetrans(uint8_t t, char *buf)
{
	if (t >= 48)
		memcpy(buf, "error trans", 11);
	else
		memcpy(buf, transstr[t], 11);
	buf[11] = '\0';
}

_static cube_fast_t
move(cube_fast_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:
		DBG_LOG("move error, unknown move\n");
		return zero_fast;
	}
}

_static cube_fast_t
transform(cube_fast_t c, uint8_t t)
{
	switch (t) {
	case _trans_UFr:
		return _trans_rotation(UFr, c);
	case _trans_ULr:
		return _trans_rotation(ULr, c);
	case _trans_UBr:
		return _trans_rotation(UBr, c);
	case _trans_URr:
		return _trans_rotation(URr, c);
	case _trans_DFr:
		return _trans_rotation(DFr, c);
	case _trans_DLr:
		return _trans_rotation(DLr, c);
	case _trans_DBr:
		return _trans_rotation(DBr, c);
	case _trans_DRr:
		return _trans_rotation(DRr, c);
	case _trans_RUr:
		return _trans_rotation(RUr, c);
	case _trans_RFr:
		return _trans_rotation(RFr, c);
	case _trans_RDr:
		return _trans_rotation(RDr, c);
	case _trans_RBr:
		return _trans_rotation(RBr, c);
	case _trans_LUr:
		return _trans_rotation(LUr, c);
	case _trans_LFr:
		return _trans_rotation(LFr, c);
	case _trans_LDr:
		return _trans_rotation(LDr, c);
	case _trans_LBr:
		return _trans_rotation(LBr, c);
	case _trans_FUr:
		return _trans_rotation(FUr, c);
	case _trans_FRr:
		return _trans_rotation(FRr, c);
	case _trans_FDr:
		return _trans_rotation(FDr, c);
	case _trans_FLr:
		return _trans_rotation(FLr, c);
	case _trans_BUr:
		return _trans_rotation(BUr, c);
	case _trans_BRr:
		return _trans_rotation(BRr, c);
	case _trans_BDr:
		return _trans_rotation(BDr, c);
	case _trans_BLr:
		return _trans_rotation(BLr, c);
	case _trans_UFm:
		return _trans_mirrored(UFm, c);
	case _trans_ULm:
		return _trans_mirrored(ULm, c);
	case _trans_UBm:
		return _trans_mirrored(UBm, c);
	case _trans_URm:
		return _trans_mirrored(URm, c);
	case _trans_DFm:
		return _trans_mirrored(DFm, c);
	case _trans_DLm:
		return _trans_mirrored(DLm, c);
	case _trans_DBm:
		return _trans_mirrored(DBm, c);
	case _trans_DRm:
		return _trans_mirrored(DRm, c);
	case _trans_RUm:
		return _trans_mirrored(RUm, c);
	case _trans_RFm:
		return _trans_mirrored(RFm, c);
	case _trans_RDm:
		return _trans_mirrored(RDm, c);
	case _trans_RBm:
		return _trans_mirrored(RBm, c);
	case _trans_LUm:
		return _trans_mirrored(LUm, c);
	case _trans_LFm:
		return _trans_mirrored(LFm, c);
	case _trans_LDm:
		return _trans_mirrored(LDm, c);
	case _trans_LBm:
		return _trans_mirrored(LBm, c);
	case _trans_FUm:
		return _trans_mirrored(FUm, c);
	case _trans_FRm:
		return _trans_mirrored(FRm, c);
	case _trans_FDm:
		return _trans_mirrored(FDm, c);
	case _trans_FLm:
		return _trans_mirrored(FLm, c);
	case _trans_BUm:
		return _trans_mirrored(BUm, c);
	case _trans_BRm:
		return _trans_mirrored(BRm, c);
	case _trans_BDm:
		return _trans_mirrored(BDm, c);
	case _trans_BLm:
		return _trans_mirrored(BLm, c);
	default:
		DBG_LOG("transform error, unknown transformation\n");
		return zero_fast;
	}
}