public Builder mergeFrom(
          com.google.protobuf.CodedInputStream input,
          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
          throws java.io.IOException {
        com.google.protobuf.UnknownFieldSet.Builder unknownFields =
          com.google.protobuf.UnknownFieldSet.newBuilder(
            this.getUnknownFields());
        while (true) {
          int tag = input.readTag();
          switch (tag) {
            case 0:
              this.setUnknownFields(unknownFields.build());
              onChanged();
              return this;
            default: {
              if (!parseUnknownField(input, unknownFields,
                                     extensionRegistry, tag)) {
                this.setUnknownFields(unknownFields.build());
                onChanged();
                return this;
              }
              break;
            }
            case 8: {
              bitField0_ |= 0x00000001;
              categoryBits_ = input.readInt32();
              break;
            }
            case 16: {
              bitField0_ |= 0x00000002;
              maskBits_ = input.readInt32();
              break;
            }
            case 24: {
              bitField0_ |= 0x00000004;
              groupIndex_ = input.readInt32();
              break;
            }
          }
        }
      }