attack.c

#include "ark.h"

// Direction Arrays for different pieces
const int KnDir[] = {+8, +12, +19, +21, -8, -12, -19, -21};
const int RkDir[] = {-1, -10, 1, 10};
const int BiDir[] = {-9, -11, 11, 9};
const int KiDir[] = {-9, -11, 11, 9, -1, -10, 1, 10};

// Checking Arrays for Double Piece Attacking the same square
// const int 

// Function to find whether a particular square is attacked by the given side
int isSqAttacked(const int sq, const int side, const S_BOARD *board){

    ASSERT(SqOnBoard(sq));
    ASSERT(SideValid(side));
    ASSERT(CheckBoard(board));

    // Pawns
    if(side == WHITE){
        if(board->pieces[sq-9] == wP || board->pieces[sq-11] == wP)
            return TRUE;
    }else{
        if(board->pieces[sq+9] == bP || board->pieces[sq+11] == bP)
            return TRUE;
    }

    // Knight
    for(int i =  0; i < 8; i++){
        int piece = board->pieces[sq + KnDir[i]];
        if(piece != OFF_BOARD && IsKn(piece) && PieceCol[piece] == side){
            return TRUE;
        }
    }

    // King
    for(int i = 0; i < 8; i++){
        int piece = board->pieces[sq + KiDir[i]];
        if(piece != OFF_BOARD && IsKi(piece) && PieceCol[piece] == side){
            return TRUE;
        }
    }

    // Rooks and Queens
    for(int i = 0; i < 4; i++){
        int t_sq = sq;
        t_sq += RkDir[i];
        int piece = board->pieces[t_sq];
        while(piece != OFF_BOARD){
            if(piece != EMPTY){
                if(IsRQ(piece) && PieceCol[piece] == side){
                    return TRUE;
                }
                break;
            }
            t_sq += RkDir[i];
            piece = board->pieces[t_sq];
        }
    }


    // Bishop and Queens
    for(int i = 0; i < 4; i++){
        int t_sq = sq;
        t_sq += BiDir[i];
        int piece = board->pieces[t_sq];
        while(piece != OFF_BOARD){
            if(piece != EMPTY){
                if(IsBQ(piece) && PieceCol[piece] == side){
                    return TRUE;
                }
                break;
            }
            t_sq += BiDir[i];
            piece = board->pieces[t_sq];
        }
    }


    return FALSE;
}


int isSqDoublePiece(const int gpiece, const int g_sq, const int sq, const S_BOARD *board){

    if(gpiece == wP || gpiece == bP || gpiece == wK || gpiece == bK || gpiece == EMPTY){
        return FALSE;
    }

    if(IsKn(gpiece)){
        for(int i =  0; i < 8; i++){
            int piece = board->pieces[sq + KnDir[i]];
            if(piece != OFF_BOARD && IsKn(piece) && PieceCol[piece] == board->side){
                return TRUE;
            }
        }
        return FALSE;
    }

    if(IsRQ(gpiece)){
        for(int i = 0; i < 4; i++){
            int t_sq = sq;
            t_sq += RkDir[i];
            int piece = board->pieces[t_sq];
            while(piece != OFF_BOARD)
            {
                if(piece != EMPTY){
                    if(IsRQ(piece) && PieceCol[piece] == board->side){
                        if(piece == gpiece && t_sq != g_sq){
                            return TRUE;
                        }
                    }
                    break;
                }
                t_sq += RkDir[i];
                piece = board->pieces[t_sq];
            }

        }

        return FALSE;
    }

    if(IsBQ(gpiece)){
        for(int i = 0; i < 4; i++){
            int t_sq = sq;
            t_sq += BiDir[i];
            int piece = board->pieces[t_sq];
            while(piece != OFF_BOARD)
            {
                if(piece != EMPTY){
                    if(IsBQ(piece) && PieceCol[piece] == board->side){
                        if(piece == gpiece && t_sq != g_sq){
                            return TRUE;
                        }
                    }
                    break;
                }
                t_sq += BiDir[i];
                piece = board->pieces[t_sq];
            }

        }

        return FALSE;
    }

    return FALSE;

}