1 files changed, 43 insertions, 0 deletions
diff --git a/interactor/common.js b/interactor/common.js
new file mode 100644
index 0000000..dbc3484
--- /dev/null
+++ b/interactor/common.js
@@ -0,0 +1,43 @@
+var W=7,H=8;
+
+function emptyboard(){
+	return new Array(H).fill(0).map(function(){
+		return new Array(W).fill(0).map(function(){
+			return {n:0,c:0};
+		});
+	});
+}
+
+function bdcopy(bd){
+	return bd.map(function(r){
+		return r.map(function(c){
+			return {n:c.n,c:c.c};
+		});
+	});
+}
+
+function stabilise(bd){
+	var newbd;
+	var changes;
+	var x,y,nnei,quo;
+	do {
+		changes=false;
+		newbd=bdcopy(bd);
+		for(y=0;y<H;y++){
+			for(x=0;x<W;x++){
+				nnei=(y>0)+(x>0)+(y<H-1)+(x<W-1);
+				if(bd[y][x].n>=nnei){
+					quo=~~(bd[y][x].n/nnei);
+					newbd[y][x].n-=quo*nnei;
+					if(y>0)  {newbd[y-1][x].n+=quo;newbd[y-1][x].c=bd[y][x].c;}
+					if(x>0)  {newbd[y][x-1].n+=quo;newbd[y][x-1].c=bd[y][x].c;}
+					if(y<H-1){newbd[y+1][x].n+=quo;newbd[y+1][x].c=bd[y][x].c;}
+					if(x<W-1){newbd[y][x+1].n+=quo;newbd[y][x+1].c=bd[y][x].c;}
+					changes=true;
+				}
+			}
+		}
+		bd=newbd;
+	} while(changes);
+	return bd;
+}