+package era.mi.logic.components;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import era.mi.logic.wires.WireArray;
+import era.mi.logic.wires.WireArray.WireArrayInput;
+
+/**
+ * Models a multiplexer. Takes an arbitrary amount of input {@link WireArray}s, one of which,
+ * as determined by select, is put through to the output.
+ * @author Fabian Stemmler
+ *
+ */
+public class Demux extends BasicComponent
+{
+ private final WireArray select, in;
+ private final WireArray[] outputs;
+ private final WireArrayInput[] outputsI;
+ private final int outputSize;
+ private int selected = -1;
+
+ /**
+ * Input {@link WireArray}s and out must be of uniform length
+ * @param out Must be of uniform length with all inputs.
+ * @param select Indexes the input array which is to be mapped to the output. Must have enough bits
+ * to index all inputs.
+ * @param outputs One of these inputs is mapped to the output, depending on the select bits
+ */
+ public Demux(int processTime, WireArray in, WireArray select, WireArray... outputs)
+ {
+ super(processTime);
+ outputSize = in.length;
+
+ this.in = in;
+ this.outputs = outputs;
+ this.outputsI = new WireArrayInput[outputs.length];
+ for(int i = 0; i < this.outputsI.length; i++)
+ {
+ if(outputs[i].length != outputSize)
+ throw new IllegalArgumentException("All DEMUX wire arrays must be of uniform length!");
+ this.outputsI[i] = outputs[i].createInput();
+ }
+
+ this.select = select;
+ select.addObserver(this);
+
+ int maxInputs = 1 << select.length;
+ if(this.outputsI.length > maxInputs)
+ throw new IllegalArgumentException("There are more outputs ("
+ + this.outputsI.length + ") to the DEMUX than supported by "
+ + select.length + " select bits (" + maxInputs + ").");
+ in.addObserver(this);
+ }
+
+ @Override
+ public void compute() {
+ int selectValue = select.hasNumericValue() ? (int) select.getUnsignedValue() : -1;
+ if(selectValue >= outputsI.length)
+ selectValue = -1;
+
+ if(selected != selectValue && selected != -1)
+ outputsI[selected].clearSignals();
+
+ selected = selectValue;
+
+ if(selectValue != -1)
+ outputsI[selectValue].feedSignals(in.getValues());
+ }
+
+ @Override
+ public List<WireArray> getAllInputs()
+ {
+ return Collections.unmodifiableList(Arrays.asList(in, select));
+ }
+
+ @Override
+ public List<WireArray> getAllOutputs()
+ {
+ return Collections.unmodifiableList(Arrays.asList(outputs));
+ }
+}