bool abstract_piece::can_i_move(const board &m_board) const
{
int8_t pieces_in_between = 0;
bool found_one_g = false;
bool am_i_in_between = false;
for (int8_t irank = 0; irank < board::RANK_NUM; irank++) {
auto piece = m_board.at(pos.file, irank);
if (piece) {
if (found_one_g) {
if (piece->is_king()) {
break;
}
pieces_in_between++;
if (*piece == *this) {
am_i_in_between = true;
}
} else if (piece->is_king()) {
found_one_g = true;
}
}
}
return !am_i_in_between || pieces_in_between != 1;
}
string game::generate_fen(const board &bd)
{
std::string fen;
int8_t space = 0;
for (int8_t rank = board::RANK_NUM - 1; rank >= 0; --rank) {
for (int8_t file = 0; file < board::FILE_NUM; ++file) {
auto p = bd.at(file, rank);
if (p) {
if (space != 0) {
fen.push_back(static_cast<char>(space) + '0');
space = 0;
}
fen.push_back(p->abbr_name());
} else {
space++;
}
}
if (space != 0) {
fen.push_back(static_cast<char>(space) + '0');
space = 0;
}
fen.push_back('/');
}
fen.pop_back();//remove last '/'
return fen;
}
//If this move will close any of the surrounding cells
point will_close_any(const board & board, point idx, border_names border)
{
auto orig_idx = idx;
auto orig_idx2 = idx;
switch (border)
{
case top: orig_idx2 += point(0, -1); break;
case left: orig_idx2 += point(-1, 0); break;
case right: orig_idx2 += point(1, 0); break;
case bottom: orig_idx2 += point(0, 1); break;
}
class board copy(board);
fix_move(idx, border);
if ((board.at(idx).owner & player_owned) != empty)
return false;
copy.place(idx, border);
point idx2;
if (border == top) idx2 = idx + point(0, -1);
if (border == left) idx2 = idx + point(-1, 0);
if (border_change(board, copy, orig_idx, 3, 4))
return orig_idx;
if (border_change(board, copy, orig_idx2, 3, 4))
return orig_idx2;
return point(-1, -1);
}
//Fill this move leaves the given cell to be closed on 2 turns
bool will_remain_with_2lines(const board & board, point idx, border_names border)
{
auto orig_idx = idx;
class board copy(board);
fix_move(idx, border);
if ((board.at(idx).owner & player_owned) != empty)
return false;
copy.place(idx, border);
return border_change(board, copy, orig_idx, 1, 2);
}
bool king::is_flying_king(const position &proposed, const board &m_board) const
{
int8_t king_rank = -1;
for (int8_t irank = 0; irank < board::RANK_NUM; irank++) {
auto p = m_board.at(proposed.file, irank);
if (p) {
if (p->is_king()) {
king_rank = irank;
break;
}
}
}
if (king_rank == -1) {//there is no king, don't bother the flying king rule
return false;
}
bool triggered = true;
if (red_side) {
for (int8_t irank = proposed.rank + 1; irank < king_rank; irank++) {//proposed.rank is equal to current position's rank
if (m_board.at(proposed.file, irank)) {
triggered = false;
break;
}
}
} else {
for (int8_t irank = proposed.rank - 1; irank > king_rank; irank--) {
if (m_board.at(proposed.file, irank)) {
triggered = false;
break;
}
}
}
return triggered;
}
void abstract_piece::remove_invalid_moves(const board &m_board, int8_t min_file, int8_t max_file, int8_t min_rank, int8_t max_rank)
{
for (auto it = avail_pos.begin(); it != avail_pos.end();) {
bool invalid = false;
if (it->not_in_range(min_file, max_file, min_rank, max_rank)) {
invalid = true;
} else {
auto target_piece = m_board.at(*it);
if (target_piece) {
//can't capture same-side pieces
if (target_piece->red_side == this->red_side) {
invalid = true;
}
}
}
if (invalid) {
it = avail_pos.erase(it);
} else {
++it;
}
}
}
//for checking if they won, we can simplify because if we check every turn
//then we *know* that a winning sequence must include that cell
bool check_win(board& b, unsigned x, char id, unsigned to_win) { //x == bin of last move
unsigned h = b.height();
unsigned w = b.num_bins();
unsigned y = 0;
for (; y < h; ++y) {
if (b[x][y] == 0) {
break;
}
}
--y;
//last move was at x,y
//check row
if (check_win(range<adapters::horiz_it>(b.at(0, y), b.at(w, y)), id, to_win)) {
return true;
}
//check column
if (check_win(range<adapters::vert_it>(b.at(x, 0), b.at(x, h)), id, to_win)) {
return true;
}
//check diagonals
int intercept;
int hs = h; //h signed
int ws = w; //w signed
unsigned xi;
unsigned xf;
unsigned yi;
unsigned yf;
//up slope:
intercept = y - x;
//all of these magic numbers are based off geometry. I'm not going
//to prove it, as this is a program, not a proof, but if you want to
//see it, it's not hard. My copy is on a receipt somewhere in the
//trash :/
if (intercept < 0) {
xi = (unsigned) -intercept;
yi = 0;
}
else {
xi = 0;
yi = (unsigned) intercept;
}
if (intercept < hs - ws) {
xf = w;
yf = (unsigned)(ws + intercept);
}
else {
xf = (unsigned)(hs - intercept);
yf = h;
}
if (check_win(range<adapters::pos_diag_it>(b.at(xi, yi), b.at(xf, yf)), id, to_win)) {
return true;
}
//down slope
//there are some unsigned -1s because i need an invalid index that is
//= to --0, so the underflow is OK. It will never be dereferenced.
intercept = x + y;
if (intercept < hs) {
xi = 0;
yi = (unsigned) intercept;
}
else {
xi = (unsigned)(intercept - hs) + 1;
yi = h - 1;
}
if (intercept < ws) {
xf = (unsigned) intercept + 1;
yf = (unsigned) -1;
}
else {
xf = w;
yf = (unsigned)(intercept - ws);
}
if (check_win(range<adapters::neg_diag_it>(b.at(xi, yi), b.at(xf, yf)), id, to_win)) {
return true;
}
return false;
}