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1   /*
2    * Copyright © 2016 Greg Chabala
3    *
4    * This file is part of brick-control-lab.
5    *
6    * brick-control-lab is free software: you can redistribute it and/or modify
7    * it under the terms of the GNU Lesser General Public License as
8    * published by the Free Software Foundation, either version 3 of the
9    * License, or (at your option) any later version.
10   *
11   * brick-control-lab is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   * GNU Lesser General Public License for more details.
15   *
16   * You should have received a copy of the GNU Lesser General Public License
17   * along with brick-control-lab.  If not, see http://www.gnu.org/licenses/.
18   */
19  package org.chabala.brick.controllab;
20  
21  import java.util.Collections;
22  import java.util.EnumSet;
23  import java.util.Set;
24  
25  /**
26   * Identifiers for the output ports on the control lab.
27   */
28  public enum OutputId {
29      /** Output A. */ A,
30      /** Output B. */ B,
31      /** Output C. */ C,
32      /** Output D. */ D,
33      /** Output E. */ E,
34      /** Output F. */ F,
35      /** Output G. */ G,
36      /** Output H. */ H;
37  
38      /**
39       * Convenience constant for specifying all output ports.
40       */
41      public static final Set<OutputId> ALL = Collections.unmodifiableSet(EnumSet.allOf(OutputId.class));
42  
43      /**
44       * Encodes values from a {@link Set} of {@link Enum}s to a byte. Uses the
45       * ordinal of the Enum as the position of the bit in the byte to set high.
46       *
47       * @param set set of values to be encoded
48       * @param <T> type of Enum, only used with {@link OutputId} internally
49       * @return a byte with high bits relating to the values in the set
50       */
51      public static <T extends Enum<T>> byte encodeSetToByte(Set<T> set) {
52          byte r = 0;
53          for (T value : set) {
54              r |= 1 << value.ordinal();
55          }
56          return r;
57      }
58  
59      private static final OutputId[] ENUM_VALUES = values();
60  
61      /**
62       * Decodes a byte into a {@link Set} of {@link OutputId}s.
63       * @param b byte where each bit corresponds to the ordinal of an Output
64       * @return a Set containing the desired Outputs
65       */
66      public static Set<OutputId> decodeByteToSet(byte b) {
67          Set<OutputId> enumSet = EnumSet.noneOf(OutputId.class);
68          int byteAsInt = Byte.toUnsignedInt(b);
69          for (int bit = 0; bit < Byte.SIZE; bit++) {
70              if ((byteAsInt & 1 << bit) > 0) {
71                  enumSet.add(ENUM_VALUES[bit]);
72              }
73          }
74          return enumSet;
75      }
76  }