attack.cpp

#include "globals.h"

int LineCheck(const int s,const int sq,const int d,const int p);
bool LineCheck2(const int s,const int sq,const int d,const int p1,const int p2);
/*

Attack returns true if one side attacks a given square and false if it doesn't.
It is used to tell if a King is in check, but can have other uses.

*/
bool Attack(const int s,const int x)
{
if(s==0)
{
if(row[x]>1)
{
if(col[x]<7 && color[x-7] == s && board[x-7] == 0)
{
return true;
}
if(col[x]>0 && color[x-9] == s && board[x-9] == 0)
{
return true;
}
}
}
else if(row[x]<6)
{
if(col[x]>0 && color[x+7] == s && board[x+7] == 0)
{
return true;
}
if(col[x]<7 && color[x+9] == s && board[x+9] == 0)
{
return true;
}
}

int k = 0;
int sq = knight_moves[x][k];

while(sq > -1)
{
if(color[sq] == s && board[sq]==N)
return true;
k++;
sq = knight_moves[x][k];
}

if(LineCheck2(s,x,NE,B,Q)) return true;
if(LineCheck2(s,x,NW,B,Q)) return true;
if(LineCheck2(s,x,SW,B,Q)) return true;
if(LineCheck2(s,x,SE,B,Q)) return true;

if(LineCheck2(s,x,NORTH,R,Q)) return true;
if(LineCheck2(s,x,SOUTH,R,Q)) return true;
if(LineCheck2(s,x,EAST,R,Q)) return true;
if(LineCheck2(s,x,WEST,R,Q)) return true;

if(abs(col[x] - col[kingloc[s]])<2 && abs(row[x] - row[kingloc[s]])<2)
{
return true;
}
return false;
}
/*

LowestAttacker is similar to Attack. It returns the square the weakest attacker of the given side and given square.
It returns -1 if there are no attackers.
It is used to find the next piece that will recapture, but can have other uses.

*/
int LowestAttacker(const int s,const int x)
{
if(s==0)
{
if(row[x]>1)
{
if(col[x]<7 && color[x-7] == s && board[x-7] == 0)
{
return x-7;
}
if(col[x]>0 && color[x-9] == s && board[x-9] == 0)
{
return x-9;
}
}
}
else if(row[x]<6)
{
if(col[x]>0 && color[x+7] == s && board[x+7] == 0)
{
return x+7;
}
if(col[x]<7 && color[x+9] == s && board[x+9] == 0)
{
return x+9;
}
}

int k = 0;
int sq = knight_moves[x][k];

while(sq > -1)
{
if(color[sq] == s && board[sq]==N)
return sq;
k++;
sq = knight_moves[x][k];
}

sq = LineCheck(s,x,NE,B); if(sq>-1) return sq;
sq = LineCheck(s,x,NW,B); if(sq>-1) return sq;
sq = LineCheck(s,x,SW,B); if(sq>-1) return sq;
sq = LineCheck(s,x,SE,B); if(sq>-1) return sq;

sq = LineCheck(s,x,NORTH,R); if(sq>-1) return sq;
sq = LineCheck(s,x,SOUTH,R); if(sq>-1) return sq;
sq = LineCheck(s,x,EAST,R); if(sq>-1) return sq;
sq = LineCheck(s,x,WEST,R); if(sq>-1) return sq;

sq = LineCheck(s,x,NORTH,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,SOUTH,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,EAST,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,WEST,Q); if(sq>-1) return sq;

sq = LineCheck(s,x,NE,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,NW,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,SW,Q); if(sq>-1) return sq;
sq = LineCheck(s,x,SE,Q); if(sq>-1) return sq;

if(abs(col[x] - col[kingloc[s]])<2 && abs(row[x] - row[kingloc[s]])<2)
{
return kingloc[s];
}
return -1;
}
/*

LineCheck searches a line in direction d for the given piece of the given side.
It returns -1 if there are none.

*/
int LineCheck(const int s,int sq,const int d,const int p)
{
sq = qrb_moves[sq][d];
while(sq > -1)
{
if(color[sq] != EMPTY)
{
if(board[sq] == p && color[sq] == s)
return sq;
break;
}
sq = qrb_moves[sq][d];
}
return -1;
}
/*

LineCheck2 searches a line in direction d for the given pieces of the given side.
On diagonals it searches for bishops and queens, while on ranks or files it
searches for rooks and queens.
It returns -1 if there are none.

*/
bool LineCheck2(const int s,int sq,const int d,const int p1,const int p2)
{
sq = qrb_moves[sq][d];
while(sq > -1)
{
if(color[sq] != EMPTY)
{
if((board[sq] == p1 || board[sq] == p2) && color[sq] == s)
return true;
break;
}
sq = qrb_moves[sq][d];
}
return false;
}