/* Copyright (c) 2010, Carl Burch. License information is located in the
* com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */
package com.cburch.logisim.std.gates;
import java.awt.Graphics;
import com.cburch.logisim.analyze.model.Expression;
import com.cburch.logisim.analyze.model.Expressions;
import com.cburch.logisim.data.AttributeSet;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.Instance;
import com.cburch.logisim.instance.InstancePainter;
import com.cburch.logisim.instance.InstanceState;
import com.cburch.logisim.tools.WireRepairData;
import com.cburch.logisim.util.GraphicsUtil;
class XorGate extends AbstractGate {
public static XorGate FACTORY = new XorGate();
private XorGate() {
super("XOR Gate", Strings.getter("xorGateComponent"), true);
setAdditionalWidth(10);
setIconNames("xorGate.gif", "xorGateRect.gif", "dinXorGate.gif");
setPaintInputLines(true);
}
@Override
public String getRectangularLabel(AttributeSet attrs) {
if (attrs == null) return "";
boolean isOdd = false;
Object behavior = attrs.getValue(GateAttributes.ATTR_XOR);
if (behavior == GateAttributes.XOR_ODD) {
Object inputs = attrs.getValue(GateAttributes.ATTR_INPUTS);
if (inputs == null || ((Integer) inputs).intValue() != 2) {
isOdd = true;
}
}
return isOdd ? "2k+1" : "=1";
}
@Override
public void paintIconShaped(InstancePainter painter) {
Graphics g = painter.getGraphics();
GraphicsUtil.drawCenteredArc(g, 2, -5, 22, -90, 53);
GraphicsUtil.drawCenteredArc(g, 2, 23, 22, 90, -53);
GraphicsUtil.drawCenteredArc(g, -10, 9, 16, -30, 60);
GraphicsUtil.drawCenteredArc(g, -12, 9, 16, -30, 60);
}
@Override
protected void paintShape(InstancePainter painter, int width, int height) {
PainterShaped.paintXor(painter, width, height);
}
@Override
protected void paintDinShape(InstancePainter painter, int width, int height,
int inputs) {
PainterDin.paintXor(painter, width, height, false);
}
@Override
protected Value computeOutput(Value[] inputs, int numInputs,
InstanceState state) {
Object behavior = state.getAttributeValue(GateAttributes.ATTR_XOR);
if (behavior == GateAttributes.XOR_ODD) {
return GateFunctions.computeOddParity(inputs, numInputs);
} else {
return GateFunctions.computeExactlyOne(inputs, numInputs);
}
}
@Override
protected boolean shouldRepairWire(Instance instance, WireRepairData data) {
return !data.getPoint().equals(instance.getLocation());
}
@Override
protected Expression computeExpression(Expression[] inputs, int numInputs) {
return xorExpression(inputs, numInputs);
}
@Override
protected Value getIdentity() { return Value.FALSE; }
protected static Expression xorExpression(Expression[] inputs, int numInputs) {
if (numInputs > 2) {
throw new UnsupportedOperationException("XorGate");
}
Expression ret = inputs[0];
for (int i = 1; i < numInputs; i++) {
ret = Expressions.xor(ret, inputs[i]);
}
return ret;
}
}