fscomch--communication between multiple chess processes

1 files changed, 154 insertions, 0 deletions

diff --git a/src/chesshelpers.c b/src/chesshelpers.c
new file mode 100644
index 0000000..b64a0f4
--- /dev/null
+++ b/src/chesshelpers.c
@@ -0,0 +1,154 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "vector.h"
+#include "chesshelpers.h"
+
+board_t init_board(int** pieces) {
+	board_t board;
+	board.pieces = pieces;
+	board.whiteCanCastleKingside = 1;
+	board.whiteCanCastleQueenside = 1;
+	board.blackCanCastleKingside = 1;
+	board.blackCanCastleQueenside = 1;
+	board.lastPawnMove = -1;
+	return board;
+}
+//function applies side effects to board values like king move state
+board_t make_move(board_t board, vector_t origin, vector_t end) {
+	int piece = board.pieces[origin.mx][origin.my];
+	int captured = board.pieces[end.mx][end.my];
+	board.pieces[origin.mx][origin.my] = 0;
+	board.pieces[end.mx][end.my] = piece;
+	//white king moved
+	if(piece == king) {
+		board.whiteCanCastleQueenside = 0;
+		board.whiteCanCastleKingside = 0;
+		//if the king moved farther than it normally could, move must have been castling. move the rook as well
+		if(origin.mx == 4 && end.mx == 6) {
+			board = make_move(board, init_vector(7, 7), init_vector(5, 7));
+		}
+		else if(origin.mx == 4 && end.mx == 2) {
+			board = make_move(board, init_vector(0, 7), init_vector(3, 7));
+		}
+	}
+	//white kingside rook moved
+	else if(origin.mx == 7 && origin.my == 7) {
+		board.whiteCanCastleKingside = 0;
+	}
+	//white queenside rook moved
+	else if(origin.mx == 0 && origin.my == 7) {
+		board.whiteCanCastleQueenside = 0;
+	}
+	//black king moved
+	else if(piece == king + 6) {
+		board.blackCanCastleQueenside = 0;
+		board.blackCanCastleKingside = 0;
+		//if the king moved farther than it normally could, move must have been castling. move the rook as well
+		if(origin.mx == 4 && end.mx == 6) {
+			board = make_move(board, init_vector(7, 0), init_vector(5, 0));
+		}
+		else if(origin.mx == 4 && end.mx == 2) {
+			board = make_move(board, init_vector(0, 0), init_vector(3, 0));
+		}
+	}
+	//black kingside rook moved
+	else if(origin.mx == 7 && origin.my == 0) {
+		board.blackCanCastleKingside = 0;
+	}
+	//black queenside rook moved
+	else if(origin.mx == 0 && origin.my == 0) {
+		board.blackCanCastleQueenside = 0;
+	}
+	//this is not an else if! lastPawnMove must be reset
+	if(piece == pawn || piece == pawn + 6) {
+		board.lastPawnMove = origin.mx;
+		//check if move was an en passant capture
+		if(captured == 0 && origin.mx != end.mx) {
+			//kill the enemy pawn
+			board.pieces[end.mx][origin.my] = 0;
+		}
+	}
+	else {
+		//en passant no longer possible
+		board.lastPawnMove = -1;
+	}
+	return board;
+}
+board_t clone_board(board_t board) {
+	board_t newBoard = board;
+	int** pieces = malloc(8 * sizeof(int*));
+	for(int r = 0; r < 8; r++) {
+		pieces[r] = malloc(8 * sizeof(int));
+		for(int c = 0; c < 8; c++) {
+			pieces[r][c] = board.pieces[r][c];
+		}
+	}
+	newBoard.pieces = pieces;
+	return newBoard;
+}
+int in_board(vector_t position) {
+	return position.mx < 8 && position.mx >= 0 && position.my < 8 && position.my >= 0;
+}
+int is_empty(board_t board, vector_t position) {
+	return board.pieces[position.mx][position.my] == 0;
+}
+int is_color(board_t board, vector_t position, int color) {
+	if(color == 0) {
+		return board.pieces[position.mx][position.my] >= 1 && board.pieces[position.mx][position.my] <= 6;
+	}	
+	else {
+		return board.pieces[position.mx][position.my] >= 7;
+	}
+}
+//returns true if a pawn that moved two squares would have been here if it moved one square
+int would_have_been_pawn(board_t board, vector_t position, int color) {
+	if(board.lastPawnMove == position.mx) {
+		if((position.my == 6 && color == 0) || (position.my == 2 && color == 1)) {
+			return 1;
+		}
+	}
+	return 0;
+}
+//converts board coordinates into algebraic notation
+char* get_readable_coords(vector_t position) {
+	char* output = malloc(3 * sizeof(char));
+	output[0] = 'a' + position.mx;
+	output[1] = '8' - position.my;
+	output[2] = '\0';
+	return output;
+}
+//gets the proper algebraic notation for the move
+char* get_move_name(board_t board, vector_t origin, vector_t end) {
+	int piece = board.pieces[origin.mx][origin.my];
+	if(piece > 6) {
+		piece -= 6;
+	}
+	if(piece != 1) {
+		char cPiece = piece == pawn ? 'P' : piece == knight ? 'N' : piece == bishop ? 'B' : piece == rook ? 'R' : piece == queen ? 'Q' : 'K';
+		int isCapture = board.pieces[end.mx][end.my] != 0;
+		char* output = calloc(isCapture ? 5 : 4, sizeof(char));
+		output[0] = cPiece;
+		if(isCapture) {
+			output[1] = 'x';
+		}
+		char* rEnd = get_readable_coords(end);
+		strcat(output, rEnd);
+		free(rEnd);
+		output[isCapture ? 4 : 3] = '\0';
+		return output;
+	}
+	else {
+		int isCapture = board.pieces[end.mx][end.my] != 0;
+		char* output = calloc(isCapture ? 5 : 3, sizeof(char));
+		if(isCapture) {
+			output[0] = 'a' + origin.mx;
+			output[1] = 'x';
+		}
+		char* rEnd = get_readable_coords(end);
+		strcat(output, rEnd);
+		free(rEnd);
+		output[isCapture ? 4 : 2] = '\0';
+		return output;
+	}
+}