era.mi/src/era/mi/logic/components/Merger.java

   1 package era.mi.logic.components;
   2
   3 import java.util.Arrays;
   4 import java.util.Collections;
   5 import java.util.List;
   6
   7 import era.mi.logic.Bit;
   8 import era.mi.logic.wires.Wire;
   9 import era.mi.logic.wires.Wire.WireEnd;
  10 import era.mi.logic.wires.WireArrayObserver;
  11
  12 public class Merger implements WireArrayObserver, Component
  13 {
  14         private WireEnd out;
  15         private WireEnd[] inputs;
  16         private int[] beginningIndex;
  17
  18         /**
  19          *
  20          * @param union  The output of merging n {@link Wire}s into one. Must have length = a1.length() + a2.length() + ... + an.length().
  21          * @param inputs The inputs to be merged into the union
  22          */
  23         public Merger(WireEnd union, WireEnd... inputs)
  24         {
  25                 this.inputs = inputs;
  26                 this.out = union;
  27                 this.beginningIndex = new int[inputs.length];
  28
  29                 int length = 0;
  30                 for (int i = 0; i < inputs.length; i++)
  31                 {
  32                         beginningIndex[i] = length;
  33                         length += inputs[i].length();
  34                         inputs[i].addObserver(this);
  35                 }
  36
  37                 if (length != union.length())
  38                         throw new IllegalArgumentException(
  39                                         "The output of merging n WireArrays into one must have length = a1.length() + a2.length() + ... + an.length().");
  40         }
  41
  42         public WireEnd getInput(int index)
  43         {
  44                 return inputs[index];
  45         }
  46
  47         public WireEnd getUnion()
  48         {
  49                 return out;
  50         }
  51
  52         @Override
  53         public void update(Wire initiator, Bit[] oldValues)
  54         {
  55                 int index = find(initiator);
  56                 int beginning = beginningIndex[index];
  57                 out.feedSignals(beginning, inputs[index].getValues());
  58         }
  59
  60         private int find(Wire w)
  61         {
  62                 for (int i = 0; i < inputs.length; i++)
  63                         if (inputs[i].getWire() == w)
  64                                 return i;
  65                 return -1;
  66         }
  67
  68         public WireEnd[] getInputs()
  69         {
  70                 return inputs.clone();
  71         }
  72
  73         @Override
  74         public List<WireEnd> getAllInputs()
  75         {
  76                 return Collections.unmodifiableList(Arrays.asList(inputs));
  77         }
  78
  79         @Override
  80         public List<WireEnd> getAllOutputs()
  81         {
  82                 return Collections.unmodifiableList(Arrays.asList(out));
  83         }
  84 }