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#include <locale.h>
#include <stdio.h>
#include <string.h>
#include "config.h"
#include "pieces.h"
void print_board(int board[128]) {
for (int rank = 7; rank >= 0; rank--) {
printf("%i|", rank + 1);
for (int file = 0; file < 8; file++) {
int piece = board[rank * 16 + file];
printf("%s ", pieces[piece]);
}
printf("\n");
}
printf(" a b c d e f g h\n");
}
void parse_FEN(char* FEN, int board[128]) {
// TODO: parse everything, not position only
int rank = 7;
int file = 0;
size_t lenght = strlen(FEN);
for (int k = 0; k < lenght; k++) {
if (FEN[k] > '0' && FEN[k] <= '8') {
int last_file = file + FEN[k] - '0';
for (file; file < last_file; file++) {
board[rank * 16 + file] = EMPTY;
}
} else {
switch (FEN[k]) {
case 'r':
board[rank * 16 + file] = BLACK | ROOK;
break;
case 'R':
board[rank * 16 + file] = ROOK;
break;
case 'n':
board[rank * 16 + file] = BLACK | KNIGHT;
break;
case 'N':
board[rank * 16 + file] = KNIGHT;
break;
case 'b':
board[rank * 16 + file] = BLACK | BISHOP;
break;
case 'B':
board[rank * 16 + file] = BISHOP;
break;
case 'q':
board[rank * 16 + file] = BLACK | QUEEN;
break;
case 'Q':
board[rank * 16 + file] = QUEEN;
break;
case 'k':
board[rank * 16 + file] = BLACK | KING;
break;
case 'K':
board[rank * 16 + file] = KING;
break;
case 'p':
board[rank * 16 + file] = BLACK | PAWN;
break;
case 'P':
board[rank * 16 + file] = PAWN;
break;
case '/':
rank--;
file = -1; // so that it becomes 0
break;
case ' ':
return;
default:
board[rank * 16 + file] = KNIGHT;
}
file++;
}
}
}
int notation_to_index(int file, int rank) {
return (rank - 1) * 16 + (file - 'a');
}
void index_to_notation(int index, char notation[2]) {
notation[0] = (index & FILE_MASK) + 'a';
notation[1] = (index >> 4) + '1';
}
void print_move(int move[2]) {
char move_in_notation[] = "xy XY";
index_to_notation(move[0], move_in_notation);
index_to_notation(move[1], move_in_notation + 3);
printf("%s\n", move_in_notation);
};
void input_move(int move[2]) {
char file;
int rank;
char file_destination;
int rank_destination;
scanf(" %c%i %c%i", &file, &rank, &file_destination, &rank_destination);
move[0] = notation_to_index(file, rank);
move[1] = notation_to_index(file_destination, rank_destination);
};
int validate_move(int move[2], int color, int* board) {
int origin = move[0];
int destination = move[1];
if ((origin & 0x88) || (destination & 0x88)) return -1;
int piece = board[origin];
int* legal_move;
if (piece % 2 != color) return -3;
switch (piece & NO_COLOR) {
case KNIGHT:
legal_move = knightMoves;
break;
case BISHOP:
legal_move = bishopMoves;
break;
case ROOK:
legal_move = rookMoves;
break;
case QUEEN:
legal_move = queenMoves;
break;
case KING:
legal_move = kingMoves;
break;
case PAWN:
if (piece & BLACK) legal_move = blackPawnMoves;
else legal_move = pawnMoves;
break;
default:
return -2;
}
while(*legal_move) {
for (int square = origin + *legal_move; !(square & 0x88); square += *legal_move) {
int target_piece = board[square];
if (square == destination) {
if (target_piece & color) return -4;
return target_piece;
}
if (target_piece != EMPTY) break;
if ((piece & NO_COLOR) == PAWN || piece == KNIGHT || piece == KING) break;
}
legal_move++;
}
return -5;
}
char* VALIDATION_ERRORS[] = {
"trying to access off-board square",
"no piece on origin square",
"opponent piece on origin square",
"trying to capture your own piece",
"move is not allowed",
};
int apply_move(int move[2], int* board) {
int origin = move[0];
int destination = move[1];
int piece = board[origin];
board[destination] = piece;
board[origin] = EMPTY;
return board[destination];
}
int main() {
int board[128];
parse_FEN(DEFAULT_FEN, board);
print_board(board);
int move[2];
int color = 0;
while (1) {
printf("Enter a move for %s:\n", COLORS[color]);
input_move(move);
int error = validate_move(move, color, board);
if (error < 0) {
printf("Invalid move: %s!\n", VALIDATION_ERRORS[-1 - error]);
} else {
apply_move(move, board);
print_board(board);
color ^= 1;
}
}
return 0;
}
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