/* * cheng.c by Eric Dietz (c) 2005 Apr 23 * take a chess position and return all legal moves out to a depth of DEPTH. */ /* defines */ #define VERSION "0.2" /* To compile as chess bot: * #define CHESSBOT and #undef EVALUATOR * To compile as evaluator: * #define EVALUATOR and #undef CHESSBOT */ #define CHESSBOT #undef EVALUATOR /* includes */ #include /* for malloc(), free() */ #include /* for printf(), getchar() */ #ifndef _WIN32 #include #include #include #include #include #include #else #include #include #include #endif // _WIN32 #include #include #include #include #include /* platform-specific defines */ #ifdef _WIN32 #define SOCKET SOCKET #define CLOSE_SOCK(fd) closesocket(fd) // on winsock2 include shutdown(fd, SD_BOTH) #define SOCKLEN_T int #define ERRNO WSAGetLastError() #define P_EINTR WSAEINTR #define P_ENOTSOCK WSAENOTSOCK #define P_EWOULDBLOCK WSAEWOULDBLOCK #define P_ENOBUFS WSAENOBUFS #define P_ENOTCONN WSAENOTCONN #define P_EINPROGRESS WSAEINPROGRESS #define PERROR xperror #define HERROR xperror void xperror(char *s) { char buf[128]; FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, 0, WSAGetLastError(), 0, buf, sizeof(buf), NULL); fprintf(stderr, "%s: %s", s, buf); } #else // _WIN32 #define SOCKET int #define CLOSE_SOCK(fd) shutdown(fd, SHUT_RDWR); close(fd) // the shutdown() blasts the socket #define SOCKLEN_T socklen_t #define ERRNO errno #define P_EINTR EINTR #define P_ENOTSOCK ENOTSOCK #define P_EWOULDBLOCK EWOULDBLOCK #define P_ENOBUFS ENOBUFS #define P_ENOTCONN ENOTCONN #define P_EINPROGRESS EINPROGRESS #define PERROR perror #define HERROR herror #endif // _WIN32 /* constants */ #define WHITE 1 #define BLACK -1 #define WHITE_PAWN 1 #define WHITE_KNIGHT 2 #define WHITE_BISHOP 3 #define WHITE_ROOK 4 #define WHITE_QUEEN 5 #define WHITE_KING 6 #define BLACK_PAWN -1 #define BLACK_KNIGHT -2 #define BLACK_BISHOP -3 #define BLACK_ROOK -4 #define BLACK_QUEEN -5 #define BLACK_KING -6 #define NOTHING 0 #define OVER_CHECKMATE 1 #define OVER_STALEMATE 2 #define OVER_LACKMATERIAL 3 #define DEPTH 2 #define NICK "chessbot" #define SERVER "localhost" #define PASSWORD "myslave" #define PORT 7001 #define BUFFERSIZE 1024 #undef VERBOSE /* chess board struct */ typedef struct chessboard chessboard; struct chessboard { int board[8][8]; /* the board arrangement */ int cas_wk, cas_wq, cas_bk, cas_bq; /* castling flags */ int en_pas; /* en passant flag */ int turn; /* whos turn it is */ }; /* move tree struct */ typedef struct movetree movetree; struct movetree { int x1, y1, x2, y2; /* from and to coords */ int promote; /* promotion flag */ chessboard position; /* the position */ movetree *next; /* pointer to next in list */ movetree *down; /* pointer to next ply */ }; /* function declarations */ void socket_loop (); void sendout (const char *format, ...); void do_read (); void do_send (); void interpret (char *data); void do_identify (char *data); void do_full (char *data); void do_ping (char *data); void do_quit (char *data); void do_okay (char *data); void do_taken (char *data); void do_joingame (char *data); void do_joined (char *data); void do_parted (char *data); void do_sitdown (char *data); void do_satdown (char *data); void do_standup (char *data); void do_stoodup (char *data); void do_opponentwaiting (char *data); void do_start (char *data); void do_offerdraw (char *data); void do_requestundo (char *data); void do_requestcancel (char *data); void do_winner (char *data); void do_move (char *data); void do_privmsg (char *data); void do_illegal (char *data); int eval (int argc, char *argv[]); int readposition (movetree *moves, char *posstr); void displayboard (chessboard board, int view); void displaymoves (movetree *moves, int curdepth); char ntop (int n); int pton (char p); void resetboard (chessboard *board); void resetmoves (movetree *moves); void clearmoves (movetree *moves); void resetandclearmoves (movetree *moves); int getmovetree (movetree *moves, int curdepth, int maxdepth); int getsq (chessboard board, int x, int y); void setsq (chessboard *board, int x, int y, int pc); void domove (chessboard *board, int x1, int y1, int x2, int y2, int promote); int islegal (chessboard board, int color, int x1, int y1, int x2, int y2); int ischeck (chessboard board, int color); int isgameover (chessboard board, int color); int getmovelist (movetree *moves); movetree *addmovetolist (movetree *moves, int num, chessboard board, int x1, int y1, int x2, int y2, int promote); /* global vars */ movetree game; char nick[128]; int table, color; char host[128]; char pass[128]; char opnick[128]; int opcolor; int port; int clone; SOCKET sockfd; char readbuf[BUFFERSIZE]; char writebuf[BUFFERSIZE]; int rbf, wbf; int hfd, cnct, slct, rcv, snd, nonb; int running; int antiidle; struct sockaddr_in serv_addr; struct hostent *server; struct timeval timeout; fd_set read_set, write_set; #ifdef _WIN32 fd_set except_set; WSADATA wsaData; #else int sockfl, pid; #endif // _WIN32 /* entry point for EVALUATOR */ #ifndef CHESSBOT int main (int argc, char *argv[]) #else // CHESSBOT int eval (int argc, char *argv[]) #endif // CHESSBOT { int depth; movetree *themoves; depth = DEPTH; themoves = malloc(sizeof(movetree)); printf("Chess evaluator by Eric v%s depth=%d\n", VERSION, depth); if (argc > 1) { switch (readposition(themoves, argv[1])) { case 1: printf("illegal entry.\n"); clearmoves(themoves); return 1; case 2: printf("** WARNING **: starting position is illegal.\n"); } } else { printf("no command-line given; assuming default. generator:\n"); printf("cheng RNBQKBNRPPPPPPPP................................pppppppprnbqkbnrKQkq.W\n"); resetmoves(themoves); } displayboard(themoves->position, WHITE); getmovetree(themoves, 1, depth); displaymoves(themoves, 0); printf("\n\npress enter to continue.\n"); getchar(); clearmoves(themoves); return 0; } /* entry point for CHESSBOT */ #ifdef CHESSBOT int main (int argc, char *argv[]) #else // CHESSBOT int eval (int argc, char *argv[]) #endif // CHESSBOT { memset(nick, 0, sizeof(nick)); memset(pass, 0, sizeof(pass)); strcpy(pass, PASSWORD); strcpy(opnick, "(noone)"); table = 0; color = 0; opcolor = 0; running = 1; antiidle = 50; timeout.tv_sec = 10; timeout.tv_usec = 0; #ifdef _WIN32 if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) { printf("unable to initialize winsock\n"); return 1; } #endif // _WIN32 sockfd = socket(AF_INET, SOCK_STREAM, 0); hfd = (int)sockfd; memset(readbuf, 0, sizeof(readbuf)); memset(writebuf, 0, sizeof(writebuf)); rbf = 0; wbf = 0; if (sockfd == -1) { printf("error making socket\n"); return 1; } if (argc < 2) { printf("no parameter given; using default\n"); strcpy(host, SERVER); port = PORT; clone = 0; } else if (argc < 3) { strcpy(host, argv[1]); port = PORT; clone = 0; } else if (argc < 4) { strcpy(host, argv[1]); port = atoi(argv[2]); clone = 0; } else { strcpy(host, argv[1]); port = atoi(argv[2]); clone = atoi(argv[3]); } memset((char *)&serv_addr, 0, sizeof(serv_addr)); serv_addr.sin_family = AF_INET; if ((serv_addr.sin_addr.s_addr = inet_addr(host)) == -1) { server = gethostbyname(host); if (server == NULL) { printf("error resolving server address: %s\n", host); return 1; } else { memcpy((char *)&serv_addr.sin_addr.s_addr, (char *)server->h_addr, server->h_length); } } serv_addr.sin_port = htons(port); srand((unsigned)time(NULL)); printf("Chez " VERSION " chess bot, attempting to connect to %s[%s]:%i...\n", host, inet_ntoa(serv_addr.sin_addr), port ); cnct = connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)); if (cnct == -1) { // we immediately got an error (probably connection refused from localhost) printf("Unable to connect to host: connection refused.\n"); return 0; } else if (cnct == 0) { // we opened the socket instantly (probably connecting to localhost) } #ifndef _WIN32 if ((pid = fork()) < 0) { perror("fork"); return 1; } else if (pid > 0) { printf("Connection succeeded; running in background with pid %i.\n", pid); return 0; } #else printf("Connection succeeded...\n"); #endif // _WIN32 socket_loop(); #ifdef _WIN32 WSACleanup(); #endif // _WIN32 CLOSE_SOCK(sockfd); return 0; } /* socket loop */ void socket_loop () { int res = 0; FD_ZERO(&read_set); FD_SET(sockfd, &read_set); FD_ZERO(&write_set); timeout.tv_sec = 10; timeout.tv_usec = 0; // loop forever! while (running) { // block poll for something to happen slct = select(hfd+1, &read_set, &write_set, NULL, &timeout); antiidle -= timeout.tv_sec; if (slct == -1) { // a select error occured... if (!( (ERRNO == P_EINTR) || (ERRNO == P_ENOTSOCK) )) { res++; if (res > 5) { PERROR("select"); exit(1); } } else { } } else if (slct == 0) { // just means select() timed out.... timeout.tv_sec = 10; timeout.tv_usec = 0; } else { // something happened if (FD_ISSET(sockfd, &read_set)) { // client is waiting to speak do_read(); } if (FD_ISSET(sockfd, &write_set)) { // client buffer is ready for writing... do_send(); } } // anti idle... if (antiidle <= 0) { sendout("UPTI"); antiidle = 50; } // add clients back to list of select()'s FD_SET FD_ZERO(&read_set); FD_ZERO(&write_set); FD_SET(sockfd, &read_set); if (wbf > 0) FD_SET(sockfd, &write_set); } } /* send data to the server */ void sendout (const char *format, ...) { char vbuf[1024]; va_list vl; vbuf[0] = '\0'; va_start(vl, format); vsprintf(vbuf, format, vl); va_end(vl); if (strlen(vbuf) + strlen(writebuf) > sizeof(writebuf) - 3) { // sendqueue exceeded... exit(1); } strcat(writebuf, vbuf); strcat(writebuf, "\r\n"); wbf = (int)strlen(writebuf); #ifdef VERBOSE printf("sent: %s\n", vbuf); #endif // VERBOSE do_send(); } /* read data from the server to the buffer */ void do_read () { char vbuf[1024]; int i; vbuf[0] = '\0'; rcv = recv(sockfd, vbuf, sizeof(vbuf)-1, 0); if (rcv == -1) { // read error: connection reset by peer... exit(1); } else if (rcv == 0) { // socket closed... exit(0); } else { if (rbf + rcv + 1 > sizeof(readbuf)) { // receivequeue exceeded... exit(1); } vbuf[rcv] = '\0'; strcat(readbuf, vbuf); rbf = (int)strlen(readbuf); vbuf[0] = '\0'; for (i = 0; i < rbf; i++) { if (readbuf[i] == '\n') { readbuf[i] = '\0'; interpret(readbuf); strcpy(vbuf, readbuf+i+1); memset(readbuf,0,sizeof(readbuf)); strcpy(readbuf, vbuf); rbf = (int)strlen(readbuf); i = -1; } } } } /* send data from the bugffer to the server */ void do_send () { snd = send(sockfd, writebuf, wbf, 0); if (snd <= 0) // some error... { if ( (ERRNO == P_EWOULDBLOCK) || #ifndef _WIN32 (ERRNO == EAGAIN) || #endif // _WIN32 (ERRNO == P_ENOBUFS) ) { snd = 0; } else { // write error: connection reset by peer... exit(1); } } wbf -= snd; if (snd > 0) strcpy(writebuf, writebuf + snd); if (wbf < 0) wbf = 0; if (wbf > 0 && !FD_ISSET(sockfd, &write_set)) FD_SET(sockfd, &write_set); } /* interpret a command */ void interpret (char *data) { char *parms = data+5; #ifdef VERBOSE printf("read: %s\n", data); #endif // VERBOSE if (!strncmp(data,"IDNT",4)) { do_identify(parms); } else if (!strncmp(data,"FULL",4)) { do_full(parms); } else if (!strncmp(data,"PING",4)) { do_ping(parms); } else if (!strncmp(data,"QUIT",4)) { do_quit(parms); } else if (!strncmp(data,"OKAY",4)) { do_okay(parms); } else if (!strncmp(data,"TAKN",4)) { do_taken(parms); } else if (!strncmp(data,"JOIN",4)) { do_joingame(parms); } else if (!strncmp(data,"JOND",4)) { do_joined(parms); } else if (!strncmp(data,"PRTD",4)) { do_parted(parms); } else if (!strncmp(data,"SITD",4)) { do_sitdown(parms); } else if (!strncmp(data,"SATD",4)) { do_satdown(parms); } else if (!strncmp(data,"STND",4)) { do_standup(parms); } else if (!strncmp(data,"STOD",4)) { do_stoodup(parms); } else if (!strncmp(data,"OWTN",4)) { do_opponentwaiting(parms); } else if (!strncmp(data,"STRT",4)) { do_start(parms); } else if (!strncmp(data,"ODRW",4)) { do_offerdraw(parms); } else if (!strncmp(data,"RUND",4)) { do_requestundo(parms); } else if (!strncmp(data,"RCNL",4)) { do_requestcancel(parms); } else if (!strncmp(data,"WINR",4)) { do_winner(parms); } else if (!strncmp(data,"MOVE",4)) { do_move(parms); } else if (!strncmp(data,"PMSG",4)) { do_privmsg(parms); } else if (!strncmp(data,"ILGL",4)) { do_illegal(parms); } } /* identify to the server */ void do_identify(char *data) { strcpy(nick, NICK); sendout("USER %s", nick); } /* server is full; quit */ void do_full(char *data) { printf("server is full :(\n"); exit(1); } /* avoid ping / idle timeouts */ void do_ping(char *data) { sendout("PONG %s", data); } /* disconnect */ void do_quit(char *data) { exit(1); } /* logged in; take a table */ void do_okay(char *data) { sendout("CREA"); } /* nickname taken; try again */ void do_taken(char *data) { if (clone) { if (strlen(nick) + 2 > sizeof(nick)) exit(1); strcat(nick, "_"); sendout("USER %s", nick); } else { exit(1); } } /* joined a table */ void do_joingame(char *data) { table = atoi(data); } /* someone else joined the table; talk to them */ void do_joined(char *data) { int t = atoi(data); if (t == table) { sendout("PRIV %d 1", table); sendout("MESG %d Hello I am a chess bot. If you'd like to play a game,", table); sendout("MESG %d just take a seat at whatever color you'd like, and hit start.", table); sendout("MESG %d Note: I am very early in development so", table); sendout("MESG %d it should be very easy to beat me.", table); sendout("MESG %d Last opponent: %s%s.", table, opnick, opcolor==WHITE?" (white)":opcolor==BLACK?" (black)":"" ); sendout("INVT %d %s", table, data+2+(t>99?2:t>9?1:0)); } } /* someone else parted the table */ void do_parted(char *data) { int t = atoi(data); if (t == table) { sendout("PRIV %d 0", table); sendout("STND %d", table); color = 0; } } /* sat at the table */ void do_sitdown(char *data) { int t = atoi(data); if (t == table) { color = (!strncmp(data+2+(t>99?2:t>9?1:0),"W",1)?WHITE:BLACK); } } /* someone else sat at the table */ void do_satdown(char *data) { int t = atoi(data); int n = 0; if (t == table) { n = (t>99?2:t>9?1:0); if (!strncmp(data+n+2,"W",1)) { sendout("SITD %d B", table); opcolor = WHITE; } else { sendout("SITD %d W", table); opcolor = BLACK; } strncpy(opnick, data+n+4, sizeof(opnick)); opnick[sizeof(opnick)-1] = '\0'; } } /* stood up from the table */ void do_standup(char *data) { int t = atoi(data); if (t == table) { color = 0; } } /* someone else stood up from the table */ void do_stoodup(char *data) { int t = atoi(data); if (t == table) { sendout("STND %d", table); sendout("INVT %d %s", table, data+2+(t>99?2:t>9?1:0)); } } /* opponent waiting */ void do_opponentwaiting(char *data) { sendout("STRT %d", table); } /* game has begun */ void do_start(char *data) { int legal, which, i; movetree *ourmove; resetmoves(&game); if (color == WHITE) { // my turn so let's give'er a go... legal = getmovetree(&game,1,1); if (legal > 0) { which = rand() % legal + 1; i = 1; for (ourmove = game.down; ourmove && i < which; ourmove = ourmove->next) { i++; } sendout ("MOVE %d %c%c%c%c%c", table, (char)ourmove->x1+'`', (char)ourmove->y1+'0', (char)ourmove->x2+'`', (char)ourmove->y2+'0', ntop(ourmove->promote) ); clearmoves(game.down); } } } /* opponent offered a draw */ void do_offerdraw(char *data) { // } /* opponent requested undo */ void do_requestundo(char *data) { // } /* opponent requested cancel */ void do_requestcancel(char *data) { sendout("CNCL %d", table); } /* game over */ void do_winner(char *data) { sendout("MESG %d YOU BASTARD!!!", table); } /* move made */ void do_move(char *data) { int x1, y1, x2, y2, promote; int legal, which, i; movetree *ourmove; char *c; for (c = data; *c != ' ' && *c; c++) ; c++; x1 = *c - '@'; c++; y1 = *c - '0'; c++; x2 = *c - '@'; c++; y2 = *c - '0'; c++; if (c) promote = pton(*c); else promote = 0; domove(&game.position, x1, y1, x2, y2, promote); if (game.position.turn == color) { legal = getmovetree(&game,1,1); if (legal > 0) { which = rand() % legal + 1; i = 1; for (ourmove = game.down; ourmove && i < which; ourmove = ourmove->next) { i++; } sendout ("MOVE %d %c%c%c%c%c", table, (char)ourmove->x1+'`', (char)ourmove->y1+'0', (char)ourmove->x2+'`', (char)ourmove->y2+'0', ntop(ourmove->promote) ); clearmoves(game.down); } } } /* process private messages sent to the bot */ void do_privmsg (char *data) { char *cmd; for (cmd = data; *cmd != ' ' && *cmd; cmd++) ; cmd++; if (!strncmp(cmd, pass, strlen(pass))) { cmd += strlen(pass) + 1; if (!strncmp(cmd, "show", 4)) { displayboard(game.position, color); } else { printf("Notice: sending command: %s\n", cmd); sendout("%s", cmd); } } } /* take note of illegal move errors... */ void do_illegal (char *data) { printf("Notice: server rejected move as illegal: %s\n", data); } /* parse input string to generate the starting position, and make sure it's a legal position */ int readposition (movetree *moves, char *posstr) { int wp=0,wn=0,wb=0,wr=0,wq=0,wk=0,bp=0,bn=0,bb=0,br=0,bq=0,bk=0,none=0; int wbl=0,wbd=0,bbl=0,bbd=0; int i,j; int legalpos = 1, piece = 0; resetmoves(moves); if (strlen(posstr) < 70) return 1; for (i=0; i<64; i++) if (pton(posstr[i]) == NOTHING && posstr[i] != '.') return 1; if ((posstr[64] != 'K' && posstr[64] != '.') || (posstr[65] != 'Q' && posstr[65] != '.') || (posstr[66] != 'k' && posstr[66] != '.') || (posstr[67] != 'q' && posstr[67] != '.') || !((posstr[68] >= 'a' && posstr[68] <= 'h') || (posstr[68] >= 'A' && posstr[68] <= 'H') || posstr[68] == '.') || (posstr[69] != 'W' && posstr[69] != 'B' && posstr[69] != 'w' && posstr[69] != 'b') ) return 1; for (i=0; i<8; i++) { for (j=0; j<8; j++) { piece = pton(posstr[i*8+j]); switch (piece) { case WHITE_PAWN: wp++; if (i == 0 || i == 7) legalpos = 0; break; case BLACK_PAWN: bp++; if (i == 0 || i == 7) legalpos = 0; break; case WHITE_KNIGHT: wn++; break; case BLACK_KNIGHT: bn++; break; case WHITE_BISHOP: wb++; if ((i+j) % 2) wbl++; else wbd++; break; case BLACK_BISHOP: bb++; if ((i+j) % 2) bbl++; else bbd++; break; case WHITE_ROOK: wr++; break; case BLACK_ROOK: br++; break; case WHITE_QUEEN: wq++; break; case BLACK_QUEEN: bq++; break; case WHITE_KING: wk++; break; case BLACK_KING: bk++; break; case NOTHING: none++; break; } moves->position.board[j][i] = piece; } } if (posstr[64] != 'K') moves->position.cas_wk = 0; if (posstr[65] != 'Q') moves->position.cas_wq = 0; if (posstr[66] != 'k') moves->position.cas_bk = 0; if (posstr[67] != 'q') moves->position.cas_bq = 0; if (posstr[68] >= 'a' && posstr[68] <= 'h') moves->position.en_pas = posstr[68]-'a'; if (posstr[68] >= 'A' && posstr[68] <= 'H') moves->position.en_pas = posstr[68]-'A'; if (posstr[69] == 'W' || posstr[69] == 'w') moves->position.turn = WHITE; else if (posstr[69] == 'B' || posstr[69] == 'b') moves->position.turn = BLACK; else return 1; if (wk != 1 || bk != 1 || none < 32) legalpos = 0; if (wp > 8 || bp > 8 || wp+wn+wb+wr+wq > 15 || bp+bn+bb+br+bq > 15) legalpos = 0; if ((wp == 8 && (wbl > 1 || wbd > 1)) || (bp == 8 && (bbl > 1 || bbd > 1)) ) legalpos = 0; if ((moves->position.turn == WHITE && ischeck(moves->position, BLACK)) || (moves->position.turn == BLACK && ischeck(moves->position, WHITE)) ) legalpos = 0; if (!legalpos) return 2; return 0; } /* display a board */ void displayboard (chessboard board, int view) { int i; int over, chck; printf("board:\n"); printf("castle=%c%c%c%c en_pas=%c\n", board.cas_wk?'K':'.', board.cas_wq?'Q':'.', board.cas_bk?'k':'.', board.cas_bq?'q':'.', board.en_pas?(char)board.en_pas+'a':'.' ); if (view == BLACK) { printf("white\n"); for (i=0; i <= 7; i++) printf("%i %c %c %c %c %c %c %c %c\n", i+1, ntop(board.board[7][i]), ntop(board.board[6][i]), ntop(board.board[5][i]), ntop(board.board[4][i]), ntop(board.board[3][i]), ntop(board.board[2][i]), ntop(board.board[1][i]), ntop(board.board[0][i]) ); printf(" H G F E D C B A\n"); printf("black\n"); } else { printf("black\n"); for (i=7; i >= 0; i--) printf("%i %c %c %c %c %c %c %c %c\n", i+1, ntop(board.board[0][i]), ntop(board.board[1][i]), ntop(board.board[2][i]), ntop(board.board[3][i]), ntop(board.board[4][i]), ntop(board.board[5][i]), ntop(board.board[6][i]), ntop(board.board[7][i]) ); printf(" A B C D E F G H\n"); printf("white\n"); } over = isgameover(board,board.turn); chck = ischeck(board,board.turn); printf("turn=%c %s\n",board.turn==WHITE?'W':'B', (over==OVER_CHECKMATE?"checkmate": over==OVER_STALEMATE?"stalemate": over==OVER_LACKMATERIAL?"lack-of-material": chck?"check":"") ); } /* display a move list */ void displaymoves (movetree *moves, int curdepth) { movetree *curmoves; int over, chck; for (curmoves = moves->down; curmoves; curmoves = curmoves->next) { over = isgameover(curmoves->position,curmoves->position.turn); chck = ischeck(curmoves->position,curmoves->position.turn); if (curdepth <= 0) printf("\n"); printf ("%c%c%c%c%c%c", (char)curmoves->x1+'`',(char)curmoves->y1+'0',(char)curmoves->x2+'`',(char)curmoves->y2+'0', ntop(curmoves->promote), (over==OVER_CHECKMATE?'#':(over==OVER_STALEMATE||over==OVER_LACKMATERIAL)?'=':chck?'+':'.') ); if (curdepth >= 1) printf(" "); else printf(" -> "); displaymoves(curmoves, curdepth+1); } } /* convert a piece number to character */ char ntop (int n) { switch (n) { case WHITE_KING: return 'K'; case BLACK_KING: return 'k'; case WHITE_QUEEN: return 'Q'; case BLACK_QUEEN: return 'q'; case WHITE_ROOK: return 'R'; case BLACK_ROOK: return 'r'; case WHITE_BISHOP: return 'B'; case BLACK_BISHOP: return 'b'; case WHITE_KNIGHT: return 'N'; case BLACK_KNIGHT: return 'n'; case WHITE_PAWN: return 'P'; case BLACK_PAWN: return 'p'; default: return '.'; } } /* convert a piece character to number */ int pton (char p) { switch (p) { case 'K': return WHITE_KING; case 'k': return BLACK_KING; case 'Q': return WHITE_QUEEN; case 'q': return BLACK_QUEEN; case 'R': return WHITE_ROOK; case 'r': return BLACK_ROOK; case 'B': return WHITE_BISHOP; case 'b': return BLACK_BISHOP; case 'N': return WHITE_KNIGHT; case 'n': return BLACK_KNIGHT; case 'P': return WHITE_PAWN; case 'p': return BLACK_PAWN; default: return NOTHING; } } /* reset a chess board */ void resetboard (chessboard *board) { int i, j; for (i=0; i<8; i++) for (j=2; j<6; j++) board->board[i][j] = NOTHING; for (i=0; i<8; i++) { board->board[i][1] = WHITE_PAWN; board->board[i][6] = BLACK_PAWN; } board->board[0][0] = WHITE_ROOK; board->board[1][0] = WHITE_KNIGHT; board->board[2][0] = WHITE_BISHOP; board->board[3][0] = WHITE_QUEEN; board->board[4][0] = WHITE_KING; board->board[5][0] = WHITE_BISHOP; board->board[6][0] = WHITE_KNIGHT; board->board[7][0] = WHITE_ROOK; board->board[0][7] = BLACK_ROOK; board->board[1][7] = BLACK_KNIGHT; board->board[2][7] = BLACK_BISHOP; board->board[3][7] = BLACK_QUEEN; board->board[4][7] = BLACK_KING; board->board[5][7] = BLACK_BISHOP; board->board[6][7] = BLACK_KNIGHT; board->board[7][7] = BLACK_ROOK; board->cas_wk = 1; board->cas_wq = 1; board->cas_bk = 1; board->cas_bq = 1; board->en_pas = 0; board->turn = WHITE; } /* reset a move list */ void resetmoves (movetree *moves) { moves->x1 = 0; moves->y1 = 0; moves->x2 = 0; moves->y2 = 0; resetboard(&moves->position); moves->next = NULL; moves->down = NULL; } /* clear a move list */ void clearmoves (movetree *moves) { if (moves) { clearmoves(moves->next); clearmoves(moves->down); free(moves); } } /* reset and clear a move list */ void resetandclearmoves (movetree *moves) { if (moves) { clearmoves(moves->next); clearmoves(moves->down); resetmoves(moves); } } /* get a move tree */ int getmovetree (movetree *moves, int curdepth, int maxdepth) { int ret; movetree *curmoves; ret = getmovelist(moves); if (curdepth >= maxdepth) return ret; //for (curmoves = moves->next; curmoves; curmoves = curmoves->down) for (curmoves = moves->down; curmoves; curmoves = curmoves->next) getmovetree(curmoves, curdepth + 1, maxdepth); return ret; } /* return the piece at a certain square */ int getsq (chessboard board, int x, int y) { if (x < 1 || x > 8 || y < 1 || y > 8) return NOTHING; return board.board[x-1][y-1]; } /* put a piece at a certain square */ void setsq (chessboard *board, int x, int y, int pc) { if (x < 1 || x > 8 || y < 1 || y > 8) return; board->board[x-1][y-1] = pc; } /* do a given move */ void domove (chessboard *board, int x1, int y1, int x2, int y2, int promote) { int sq; sq = getsq(*board,x1,y1); board->en_pas = 0; switch (sq) { case WHITE_PAWN: if (x1 != x2 && getsq(*board,x2,y2) == NOTHING) setsq(board,x2,5,NOTHING); /* capturing en passant */ else if (y1 == 2 && y2 == 4) board->en_pas = x1; /* moving 2 squares; set en_pas flag */ else if (y2 == 8) { /* promoting pawn */ if (promote == NOTHING) promote = WHITE_QUEEN; else if (promote < NOTHING) promote = NOTHING+NOTHING-promote; sq = promote; } break; case BLACK_PAWN: if (x1 != x2 && getsq(*board,x2,y2) == NOTHING) setsq(board,x2,4,NOTHING); /* capturing en passant */ else if (y1 == 7 && y2 == 5) board->en_pas = x1; /* moving 2 squares; set en_pas flag */ else if (y2 == 1) { /* promoting pawn */ if (promote == NOTHING) promote = BLACK_QUEEN; else if (promote > NOTHING) promote = NOTHING+NOTHING-promote; sq = promote; } break; case WHITE_ROOK: if (x1 == 1 && y1 == 1 && board->cas_wq) board->cas_wq = 0; /* clear white queenside castling flag */ else if (x1 == 8 && y1 == 1 && board->cas_wk) board->cas_wk = 0; /* clear white kingside castling flag */ break; case BLACK_ROOK: if (x1 == 8 && y1 == 8 && board->cas_bk) board->cas_bk = 0; /* clear black kingside castling flag */ else if (x1 == 1 && y1 == 8 && board->cas_bq) board->cas_bq = 0; /* clear black queenside castling flag */ break; case WHITE_KING: if (board->cas_wk) board->cas_wk = 0; /* clear white kingside castling flag */ if (board->cas_wq) board->cas_wq = 0; /* clear white queenside castling flag */ if (x1 == 5 && x2 == 7) { /* castling kingside */ setsq(board,8,1,NOTHING); setsq(board,6,1,WHITE_ROOK); } else if (x1 == 5 && x2 == 3) { /* castling queenside */ setsq(board,1,1,NOTHING); setsq(board,4,1,WHITE_ROOK); } break; case BLACK_KING: if (board->cas_bk) board->cas_bk = 0; /* clear black kingside castling flag */ if (board->cas_bq) board->cas_bq = 0; /* clear black queenside castling flag */ if (x1 == 5 && x2 == 7) { /* castling kingside */ setsq(board,8,8,NOTHING); setsq(board,6,8,BLACK_ROOK); } else if (x1 == 5 && x2 == 3) { /* castling queenside */ setsq(board,1,8,NOTHING); setsq(board,4,8,BLACK_ROOK); } break; } setsq(board,x2,y2,sq); /* and move the piece... */ setsq(board,x1,y1,NOTHING); if (board->turn == WHITE) /* and set it to the other players' turn */ board->turn = BLACK; else board->turn = WHITE; } /* check legality of a given move */ int islegal (chessboard board, int color, int x1, int y1, int x2, int y2) { int sq, sq2; /* from-square, to-square */ int dx=0, dy=0, h, k; /* iterators for bishop/rook/queen move checks */ chessboard temp; /* temp board (to test for check) */ if /* some obvious signs that a move is illegal... */ ((x1 < 1 || x1 > 8 || y1 < 1 || y1 > 8 || x2 < 1 || x2 > 8 || y2 < 1 || y2 > 8) || /* cant move off the board */ (x1 == x2 && y1 == y2) || /* cant move a piece to where it already is */ ((color == WHITE && (getsq(board,x1,y1) <= NOTHING || getsq(board,x2,y2) > NOTHING)) || /* cant move opponents piece */ (color == BLACK && (getsq(board,x1,y1) >= NOTHING || getsq(board,x2,y2) < NOTHING)) ) ) /* or capture your own piece */ return 0; sq = getsq(board,x1,y1); sq2 = getsq(board,x2,y2); temp = board; switch (sq) { case WHITE_PAWN: if (x2 - x1 < -1 || x2 - x1 > 1) /* cant jump over files */ return 0; if (x1 == x2) { if ((sq2 != NOTHING) || /* cant capture forward */ (y2 - y1 > 2 || y2 - y1 < 1) || /* can only move 1 or 2 spaces */ (y2 - y1 == 2 && (!(y1 == 2 && y2 == 4) || getsq(board,x1,3) != NOTHING)) ) /* cant jump over pieces */ return 0; } else { if (y2 - y1 != 1) /* captures must be diagonal */ return 0; if (sq2 == NOTHING) { if ((board.en_pas != x2) || /* can only do en passant if the flag is set */ (!(y1 == 5 && y2 == 6)) || /* can only do en passant on the 6th rank */ (getsq(board,x2,5) != BLACK_PAWN) ) /* can only do en passant if taking opposing pawn */ return 0; else setsq(&temp,x2,5,NOTHING); /* capturing en passant OK */ } } if (y2 == 8) /* promoting a pawn */ sq = WHITE_QUEEN; break; case BLACK_PAWN: if (x2 - x1 < -1 || x2 - x1 > 1) /* cant jump over files */ return 0; if (x1 == x2) { if ((sq2 != NOTHING) || /* cant capture forward */ (y2 - y1 < -2 || y2 - y1 > -1) ||/* can only move 1 or 2 spaces */ (y2 - y1 == -2 && (!(y1 == 7 && y2 == 5) || getsq(board,x1,6) != NOTHING)) ) /* cant jump over pieces */ return 0; } else { if (y2 - y1 != -1) /* captures must be diagonal */ return 0; if (sq2 == NOTHING) { if ((board.en_pas != x2) || /* can only do en passant if the flag is set */ (!(y1 == 4 && y2 == 3)) || /* can only do en passant on the 6th rank */ (getsq(board,x2,4) != WHITE_PAWN) ) /* can only do en passant if taking opposing pawn */ return 0; else setsq(&temp,x2,4,NOTHING); /* capturing en passant OK */ } } if (y2 == 1) /* promoting a pawn */ sq = BLACK_QUEEN; break; case WHITE_KNIGHT: case BLACK_KNIGHT: if ((x1 == x2 || y1 == y2) || /* must be L shaped move */ ((y2>y1?y2-y1:y1-y2) + (x2>x1?x2-x1:x1-x2) != 3) ) /* must be 2 in one dir and 1 in another */ return 0; break; case WHITE_QUEEN: /* note: queen move test is embedded in Bishop+Rook tests... */ case BLACK_QUEEN: case WHITE_BISHOP: case BLACK_BISHOP: if ((x2>x1?x2-x1:x1-x2) != (y2>y1?y2-y1:y1-y2)) /* must be on a diagonal */ { if (sq != WHITE_QUEEN && sq != BLACK_QUEEN) return 0; } else { if (x2 > x1) dx = 1; else dx = -1; if (y2 > y1) dy = 1; else dy = -1; h = x1 + dx; k = y1 + dy; while (!(h == x2 && k == y2) && h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (getsq(board,h,k) != NOTHING) /* found something in the way (cant jump) */ return 0; h += dx; k += dy; } } if (sq != WHITE_QUEEN && sq != BLACK_QUEEN) break; case WHITE_ROOK: case BLACK_ROOK: if (!(x1 == x2 || y1 == y2)) /* must be along a rank or file */ { if (sq != WHITE_QUEEN && sq != BLACK_QUEEN) return 0; } else { if (x2 > x1) dx = 1; else if (x2 < x1) dx = -1; else dx = 0; if (y2 > y1) dy = 1; else if (y2 < y1) dy = -1; else dy = 0; h = x1 + dx; k = y1 + dy; while (!(h == x2 && k == y2) && h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (getsq(board,h,k) != NOTHING) /* found something in the way (cant jump) */ return 0; h += dx; k += dy; } } break; case WHITE_KING: if (x2 - x1 < -1 || x2 - x1 > 1 || y2 - y1 < -1 || y2 - y1 > 1) /* only move 1 square, or... */ { if ((y1 != 1 || y2 != 1 || x1 != 5 || (x2 != 3 && x2 != 7)) || /* can only castle these coords */ (ischeck(board,WHITE)) || /* cant castle out of check */ ((x2 == 3 && (!board.cas_wk || /* cant castle if illegal or something in the way ... */ getsq(board,4,1) != NOTHING || getsq(board,3,1) != NOTHING || getsq(board,2,1) != NOTHING )) || (x2 == 7 && (!board.cas_wq || getsq(board,6,1) != NOTHING || getsq(board,7,1) != NOTHING ))) ) return 0; if (x2 == 3) { setsq(&temp,4,1,WHITE_KING); setsq(&temp,5,1,NOTHING); if (ischeck(temp,WHITE)) /* cant castle through check */ return 0; setsq(&temp,4,1,WHITE_ROOK); /* castling white queenside OK */ setsq(&temp,1,1,NOTHING); } else { setsq(&temp,6,1,WHITE_KING); setsq(&temp,5,1,NOTHING); if (ischeck(temp,WHITE)) /* cant castle through check */ return 0; setsq(&temp,6,1,WHITE_ROOK); /* castling white kingside OK */ setsq(&temp,8,1,NOTHING); } } break; case BLACK_KING: if (x2 - x1 < -1 || x2 - x1 > 1 || y2 - y1 < -1 || y2 - y1 > 1) /* only move 1 square, or... */ { if ((y1 != 8 || y2 != 8 || x1 != 5 || (x2 != 3 && x2 != 7)) || /* can only castle these coords */ (ischeck(board,BLACK)) || /* cant castle out of check */ ((x2 == 3 && (!board.cas_bk || /* cant castle if illegal or something in the way ... */ getsq(board,4,8) != NOTHING || getsq(board,3,8) != NOTHING || getsq(board,2,8) != NOTHING )) || (x2 == 7 && (!board.cas_bq || getsq(board,6,8) != NOTHING || getsq(board,7,8) != NOTHING ))) ) return 0; if (x2 == 3) { setsq(&temp,4,8,BLACK_KING); setsq(&temp,5,8,NOTHING); if (ischeck(temp,BLACK)) /* cant castle through check */ return 0; setsq(&temp,4,8,BLACK_ROOK); /* castling black queenside OK */ setsq(&temp,1,8,NOTHING); } else { setsq(&temp,6,8,BLACK_KING); setsq(&temp,5,8,NOTHING); if (ischeck(temp,BLACK)) /* cant castle through check */ return 0; setsq(&temp,6,8,BLACK_ROOK); /* castling black kingside OK */ setsq(&temp,8,8,NOTHING); } } break; } setsq(&temp,x2,y2,sq); /* try the move... */ setsq(&temp,x1,y1,NOTHING); if (ischeck(temp,color)) return 0; /* move is illegal if it puts player in check */ return 1; } /* see if a given position is check */ int ischeck (chessboard board, int color) { int i, j; /* iterators */ int kx, ky; /* location of king */ int op,on,ob,or,oq,ok; /* representation of opposing pawn,knight,bishop,rook,queen,king */ int dx=0, dy=0, h, k; /* iterators for bishop/rook/queen checks */ int sq; /* var to store pieces at various squares */ kx = 0; ky = 0; for (i=1; i <= 8 && kx == 0; i++) for (j=1; j <= 8 && ky == 0; j++) if ((color == WHITE && getsq(board,i,j) == WHITE_KING) || (color == BLACK && getsq(board,i,j) == BLACK_KING) ) { kx = i; ky = j; } if (color == WHITE) { op = BLACK_PAWN; on = BLACK_KNIGHT; ob = BLACK_BISHOP; or = BLACK_ROOK; oq = BLACK_QUEEN; ok = BLACK_KING; } else { op = WHITE_PAWN; on = WHITE_KNIGHT; ob = WHITE_BISHOP; or = WHITE_ROOK; oq = WHITE_QUEEN; ok = WHITE_KING; } if /* check by pawn? */ (getsq(board,kx-1,color==WHITE?ky+1:ky-1) == op || getsq(board,kx+1,color==WHITE?ky+1:ky-1) == op ) return 1; if /* check by knight? */ (getsq(board,kx+2,ky+1) == on || getsq(board,kx+1,ky+2) == on || getsq(board,kx-1,ky+2) == on || getsq(board,kx-2,ky+1) == on || getsq(board,kx-2,ky-1) == on || getsq(board,kx-1,ky-2) == on || getsq(board,kx+1,ky-2) == on || getsq(board,kx+2,ky-1) == on ) return 1; for (dx = -1; dx <= 1; dx += 2) /* bishop+queen check, lower-left ... */ { for (dy = -1; dy <= 1; dy += 2) /* ... to upper right diagonals */ { h = kx + dx; k = ky + dy; while (h >= 1 && h <= 8 && k >= 1 && k <= 8) { sq = getsq(board,h,k); if (sq == ob || sq == oq) /* found opposing bishop or queen along diagonal */ return 1; if (sq != NOTHING) /* found something else (so not in check) */ break; h += dx; k += dy; } } } for (i=0; i <= 1; i++) /* rook+queen check */ { for (j=0; j <= 1; j++) { if (i == 0 && j == 0) { dx = -1; dy = 0; } /* going left, */ else if (i == 0 && j == 1) { dx = 1; dy = 0; } /* right, etc... */ else if (i == 1 && j == 0) { dx = 0; dy = -1; } else if (i == 1 && j == 1) { dx = 0; dy = 1; } h = kx + dx; k = ky + dy; while (h >= 1 && h <= 8 && k >= 1 && k <= 8) { sq = getsq(board,h,k); if (sq == or || sq == oq) /* found opposing rook or queen along diagonal */ return 1; if (sq != NOTHING) /* found something else (so not in check) */ break; h += dx; k += dy; } } } if /* check by king? */ (getsq(board,kx+1,ky) == ok || getsq(board,kx+1,ky+1) == ok || getsq(board,kx,ky+1) == ok || getsq(board,kx-1,ky+1) == ok || getsq(board,kx-1,ky) == ok || getsq(board,kx-1,ky-1) == ok || getsq(board,kx,ky-1) == ok || getsq(board,kx+1,ky-1) == ok ) return 1; return 0; } /* check to see if a game is over */ int isgameover (chessboard board, int color) { /* possible return codes: * 0 (game is not over yet) * OVER_CHECKMATE * OVER_STALEMATE * OVER_LACKMATERIAL */ int i, j, u, v; /* iterators */ int dx=0, dy=0, h, k; /* iterators for bishop/rook/queen checks */ int sq; /* piece at a square */ int mov; /* legal moves found? */ int prq,wnb,bnb; /* counters for: pawn+rook+queen,white knight+bishop,black knight+bishop */ mov = 0; for (i=1; i <= 8 && mov == 0; i++) { for (j=1; j <= 8 && mov == 0; j++) { sq = getsq(board,i,j); if ((color == WHITE && sq <= NOTHING) || (color == BLACK && sq >= NOTHING)) continue; switch (sq) { case WHITE_PAWN: /* check for legal pawn moves */ if (islegal(board,color,i,j,i,j+1)) mov++; else if (islegal(board,color,i,j,i,j+2)) mov++; else if (islegal(board,color,i,j,i-1,j+1)) mov++; else if (islegal(board,color,i,j,i+1,j+1)) mov++; break; case BLACK_PAWN: if (islegal(board,color,i,j,i,j-1)) mov++; else if (islegal(board,color,i,j,i,j-2)) mov++; else if (islegal(board,color,i,j,i-1,j-1)) mov++; else if (islegal(board,color,i,j,i+1,j-1)) mov++; break; case WHITE_KNIGHT: /* check for legal knight moves */ case BLACK_KNIGHT: if (islegal(board,color,i,j,i+2,j+1)) mov++; else if (islegal(board,color,i,j,i+1,j+2)) mov++; else if (islegal(board,color,i,j,i-1,j+2)) mov++; else if (islegal(board,color,i,j,i-2,j+1)) mov++; else if (islegal(board,color,i,j,i-2,j-1)) mov++; else if (islegal(board,color,i,j,i-1,j-2)) mov++; else if (islegal(board,color,i,j,i+1,j-2)) mov++; else if (islegal(board,color,i,j,i+2,j-1)) mov++; break; case WHITE_QUEEN: /* here again we encapsulate queen check in bishop+rook checks */ case BLACK_QUEEN: case WHITE_BISHOP: /* check for legal bishop moves */ case BLACK_BISHOP: for (dx = -1; dx <= 1 && mov == 0; dx += 2) { for (dy = -1; dy <= 1 && mov == 0; dy += 2) { h = i + dx; k = j + dy; while (mov == 0 && h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (islegal(board,color,i,j,h,k)) mov++; h += dx; k += dy; } } } if (sq != WHITE_QUEEN && sq != BLACK_QUEEN) break; case WHITE_ROOK: /* check for legal rook moves */ case BLACK_ROOK: for (u=0; u <= 1 && mov == 0; u++) { for (v=0; v <= 1 && mov == 0; v++) { if (u == 0 && v == 0) { dx = -1; dy = 0; } else if (u == 0 && v == 1) { dx = 1; dy = 0; } else if (u == 1 && v == 0) { dx = 0; dy = -1; } else if (u == 1 && v == 1) { dx = 0; dy = 1; } h = i + dx; k = j + dy; while (mov == 0 && h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (islegal(board,color,i,j,h,k)) mov++; h += dx; k += dy; } } } break; case WHITE_KING: /* check for legal king moves */ case BLACK_KING: if (islegal(board,color,i,j,i+1,j)) mov++; else if (islegal(board,color,i,j,i+1,j+1)) mov++; else if (islegal(board,color,i,j,i,j+1)) mov++; else if (islegal(board,color,i,j,i-1,j+1)) mov++; else if (islegal(board,color,i,j,i-1,j)) mov++; else if (islegal(board,color,i,j,i-1,j-1)) mov++; else if (islegal(board,color,i,j,i,j-1)) mov++; else if (islegal(board,color,i,j,i+1,j-1)) mov++; /* note: no need to check for castling legality since it wont be legal if none of the above are legal */ break; } } } if (mov == 0) /* no moves found... */ { if (ischeck(board,color)) /* position is checkmate */ { return OVER_CHECKMATE; } else /* position is drawn by stalemate */ { return OVER_STALEMATE; } } prq = 0; /* otherwise, now we check for lack of material draw */ wnb = 0; bnb = 0; for (i=1; i <= 8; i++) for (j=1; j<= 8; j++) switch (getsq(board,i,j)) /* count each group of pieces */ { case WHITE_PAWN: case BLACK_PAWN: case WHITE_ROOK: case BLACK_ROOK: case WHITE_QUEEN: case BLACK_QUEEN: prq++; break; case WHITE_KNIGHT: case WHITE_BISHOP: wnb++; break; case BLACK_KNIGHT: case BLACK_BISHOP: bnb++; break; case WHITE_KING: case BLACK_KING: case NOTHING: break; } if (prq == 0 && wnb == 1 && bnb == 1) { /* for later -- add code to allow for the bizarre hypothetical situations * where there's a king and minor piece against a king and minor piece but * there could still be a win... */ return OVER_LACKMATERIAL; } else if (prq == 0 && wnb <= 1 && bnb <= 1) return OVER_LACKMATERIAL; return 0; /* made it this far? must not be over */ } /* generate a move list */ int getmovelist (movetree *moves) { /* return value for this function = number of legal moves for the position */ int i, j, u, v; /* iterators */ int dx=0, dy=0, h, k; /* iterators for bishop/rook/queen checks */ int sq; /* piece at a square */ int mov; /* number of legal moves found */ movetree *curmoves; /* pointer to moves tree */ if (isgameover(moves->position,moves->position.turn)) return 0; mov = 0; curmoves = moves; for (i=1; i <= 8; i++) { for (j=1; j <= 8; j++) { sq = getsq(moves->position,i,j); if ((moves->position.turn == WHITE && sq <= NOTHING) || (moves->position.turn == BLACK && sq >= NOTHING) ) continue; switch (sq) { case WHITE_PAWN: /* check for legal pawn moves */ if (islegal(moves->position,moves->position.turn,i,j,i,j+1)) { if (j == 7) /* also add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,WHITE_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,WHITE_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,WHITE_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,WHITE_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,NOTHING); } if (islegal(moves->position,moves->position.turn,i,j,i,j+2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j+1)) { if (j == 7) /* add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,WHITE_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,WHITE_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,WHITE_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,WHITE_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,NOTHING); } if (islegal(moves->position,moves->position.turn,i,j,i+1,j+1)) { if (j == 7) /* add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,WHITE_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,WHITE_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,WHITE_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,WHITE_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,NOTHING); } break; case BLACK_PAWN: if (islegal(moves->position,moves->position.turn,i,j,i,j-1)) { if (j == 2) /* also add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,BLACK_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,BLACK_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,BLACK_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,BLACK_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,NOTHING); } if (islegal(moves->position,moves->position.turn,i,j,i,j-2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j-1)) { if (j == 2) /* add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,BLACK_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,BLACK_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,BLACK_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,BLACK_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,NOTHING); } if (islegal(moves->position,moves->position.turn,i,j,i+1,j-1)) { if (j == 2) /* add promotions to list */ { curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,BLACK_QUEEN); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,BLACK_KNIGHT); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,BLACK_ROOK); curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,BLACK_BISHOP); } else curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,NOTHING); } break; case WHITE_KNIGHT: /* check for legal knight moves */ case BLACK_KNIGHT: if (islegal(moves->position,moves->position.turn,i,j,i+2,j+1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+2,j+1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+1,j+2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j+2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-2,j+1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-2,j+1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-2,j-1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-2,j-1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j-2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+1,j-2)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-2,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+2,j-1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+2,j-1,NOTHING); break; case WHITE_QUEEN: /* here again we encapsulate queen check in bishop+rook checks */ case BLACK_QUEEN: case WHITE_BISHOP: /* check for legal bishop moves */ case BLACK_BISHOP: for (dx = -1; dx <= 1; dx += 2) { for (dy = -1; dy <= 1; dy += 2) { h = i + dx; k = j + dy; while (h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (islegal(moves->position,moves->position.turn,i,j,h,k)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,h,k,NOTHING); h += dx; k += dy; } } } if (sq != WHITE_QUEEN && sq != BLACK_QUEEN) break; case WHITE_ROOK: /* check for legal rook moves */ case BLACK_ROOK: for (u=0; u <= 1; u++) { for (v=0; v <= 1; v++) { if (u == 0 && v == 0) { dx = -1; dy = 0; } else if (u == 0 && v == 1) { dx = 1; dy = 0; } else if (u == 1 && v == 0) { dx = 0; dy = -1; } else if (u == 1 && v == 1) { dx = 0; dy = 1; } h = i + dx; k = j + dy; while (h >= 1 && h <= 8 && k >= 1 && k <= 8) { if (islegal(moves->position,moves->position.turn,i,j,h,k)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,h,k,NOTHING); h += dx; k += dy; } } } break; case WHITE_KING: /* check for legal king moves */ case BLACK_KING: if (islegal(moves->position,moves->position.turn,i,j,i+1,j)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+1,j+1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j+1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i,j+1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j+1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j+1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j+1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-1,j-1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-1,j-1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i,j-1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i,j-1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+1,j-1)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+1,j-1,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i-2,j)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i-2,j,NOTHING); if (islegal(moves->position,moves->position.turn,i,j,i+2,j)) curmoves = addmovetolist(curmoves,mov++,moves->position,i,j,i+2,j,NOTHING); break; } } } return mov; } /* add a move to a move list */ movetree *addmovetolist (movetree *moves, int num, chessboard board, int x1, int y1, int x2, int y2, int promote) { movetree *newmoves; if (num <= 0) { moves->down = malloc(sizeof(movetree)); newmoves = moves->down; } else { moves->next = malloc(sizeof(movetree)); newmoves = moves->next; } resetmoves(newmoves); newmoves->x1 = x1; newmoves->y1 = y1; newmoves->x2 = x2; newmoves->y2 = y2; newmoves->promote = promote; newmoves->position = board; domove(&newmoves->position,x1,y1,x2,y2,promote); return newmoves; } /* end */