--- a/src/chess/pgn.c Wed Aug 26 12:59:30 2015 +0200
+++ b/src/chess/pgn.c Wed Aug 26 14:46:42 2015 +0200
@@ -194,3 +194,158 @@
return bytes;
}
+
+static size_t fen_pieces(char *str, GameState *gamestate) {
+ size_t i = 0;
+ for (int row = 7 ; row >= 0 ; row--) {
+ unsigned int skip = 0;
+ for (int file = 0 ; file < 8 ; file++) {
+ if (gamestate->board[row][file]) {
+ if (skip > 0) {
+ str[i++] = '0'+skip;
+ skip = 0;
+ }
+ switch (gamestate->board[row][file] & ~ENPASSANT_THREAT) {
+ case WHITE|KING: str[i++] = 'K'; break;
+ case WHITE|QUEEN: str[i++] = 'Q'; break;
+ case WHITE|BISHOP: str[i++] = 'B'; break;
+ case WHITE|KNIGHT: str[i++] = 'N'; break;
+ case WHITE|ROOK: str[i++] = 'R'; break;
+ case WHITE|PAWN: str[i++] = 'P'; break;
+ case BLACK|KING: str[i++] = 'k'; break;
+ case BLACK|QUEEN: str[i++] = 'q'; break;
+ case BLACK|BISHOP: str[i++] = 'b'; break;
+ case BLACK|KNIGHT: str[i++] = 'n'; break;
+ case BLACK|ROOK: str[i++] = 'r'; break;
+ case BLACK|PAWN: str[i++] = 'p'; break;
+ }
+ } else {
+ skip++;
+ }
+ }
+ if (skip > 0) {
+ str[i++] = '0'+skip;
+ }
+ if (row > 0) {
+ str[i++] = '/';
+ }
+ }
+
+ return i;
+}
+
+static size_t fen_color(char *str, GameState *gamestate) {
+ uint8_t color = opponent_color(gamestate->lastmove ?
+ (gamestate->lastmove->move.piece & COLOR_MASK) : BLACK);
+
+ str[0] = color == WHITE ? 'w' : 'b';
+
+ return 1;
+}
+
+static _Bool fen_castling_chkmoved(GameState *gamestate,
+ uint8_t row, uint8_t file) {
+
+ MoveList *ml = gamestate->movelist;
+ while (ml) {
+ if (ml->move.fromfile == file && ml->move.fromrow == row) {
+ return 1;
+ }
+ ml = ml->next;
+ }
+
+ return 0;
+}
+
+static size_t fen_castling(char *str, GameState *gamestate) {
+ _Bool K, Q, k, q;
+
+ if (fen_castling_chkmoved(gamestate, rowidx('1'), fileidx('e'))) {
+ K = Q = 0;
+ } else {
+ K = !fen_castling_chkmoved(gamestate, rowidx('1'), fileidx('h'));
+ Q = !fen_castling_chkmoved(gamestate, rowidx('1'), fileidx('a'));
+ }
+ if (fen_castling_chkmoved(gamestate, rowidx('8'), fileidx('e'))) {
+ k = q = 0;
+ } else {
+ k = !fen_castling_chkmoved(gamestate, rowidx('8'), fileidx('h'));
+ q = !fen_castling_chkmoved(gamestate, rowidx('8'), fileidx('a'));
+ }
+
+ size_t i = 0;
+ if (K) str[i++] = 'K';
+ if (Q) str[i++] = 'Q';
+ if (k) str[i++] = 'k';
+ if (q) str[i++] = 'q';
+ if (!i) str[i++] = '-';
+
+ return i;
+}
+
+static size_t fen_enpassant(char *str, GameState *gamestate) {
+
+ str[0] = '-'; str[1] = '\0';
+
+ for (int file = 0 ; file < 8 ; file++) {
+ if (gamestate->board[3][file] & ENPASSANT_THREAT) {
+ str[0] = filechr(file);
+ str[1] = rowchr(2);
+ }
+ if (gamestate->board[4][file] & ENPASSANT_THREAT) {
+ str[0] = filechr(file);
+ str[1] = rowchr(5);
+ }
+ }
+
+ return str[0] == '-' ? 1 : 2;
+}
+
+static size_t fen_halfmove(char *str, GameState *gamestate) {
+
+ unsigned int i = 0;
+ for (MoveList *move = gamestate->movelist ; move ; move = move->next) {
+ if (move->move.capture || (move->move.piece & PIECE_MASK) == PAWN) {
+ i = 0;
+ } else {
+ i++;
+ }
+ }
+
+ char m[8];
+ size_t len = sprintf(m, "%u", i);
+ memcpy(str, m, len);
+
+ return len;
+}
+
+static size_t fen_movenr(char *str, GameState *gamestate) {
+
+ MoveList *move = gamestate->movelist;
+ unsigned int i = 1;
+ while (move) {
+ i++;
+ move = move->next;
+ }
+
+ char m[8];
+ size_t len = sprintf(m, "%u", i);
+ memcpy(str, m, len);
+
+ return len;
+}
+
+void compute_fen(char *str, GameState *gamestate) {
+ str += fen_pieces(str, gamestate);
+ *str = ' '; str++;
+ str += fen_color(str, gamestate);
+ *str = ' '; str++;
+ str += fen_castling(str, gamestate);
+ *str = ' '; str++;
+ str += fen_enpassant(str, gamestate);
+ *str = ' '; str++;
+ str += fen_halfmove(str, gamestate);
+ *str = ' '; str++;
+ str += fen_movenr(str, gamestate);
+ str[0] = '\0';
+}