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;
              tag_ = input.readInt64();
              break;
            }
            case 16: {
              int rawValue = input.readEnum();
              org.box2d.proto.Box2D.PbShapeType value = org.box2d.proto.Box2D.PbShapeType.valueOf(rawValue);
              if (value == null) {
                unknownFields.mergeVarintField(2, rawValue);
              } else {
                bitField0_ |= 0x00000002;
                type_ = value;
              }
              break;
            }
            case 82: {
              org.box2d.proto.Box2D.PbVec2.Builder subBuilder = org.box2d.proto.Box2D.PbVec2.newBuilder();
              if (hasCenter()) {
                subBuilder.mergeFrom(getCenter());
              }
              input.readMessage(subBuilder, extensionRegistry);
              setCenter(subBuilder.buildPartial());
              break;
            }
            case 93: {
              bitField0_ |= 0x00000008;
              radius_ = input.readFloat();
              break;
            }
            case 162: {
              org.box2d.proto.Box2D.PbVec2.Builder subBuilder = org.box2d.proto.Box2D.PbVec2.newBuilder();
              input.readMessage(subBuilder, extensionRegistry);
              addPoints(subBuilder.buildPartial());
              break;
            }
            case 170: {
              org.box2d.proto.Box2D.PbVec2.Builder subBuilder = org.box2d.proto.Box2D.PbVec2.newBuilder();
              input.readMessage(subBuilder, extensionRegistry);
              addNormals(subBuilder.buildPartial());
              break;
            }
            case 178: {
              org.box2d.proto.Box2D.PbVec2.Builder subBuilder = org.box2d.proto.Box2D.PbVec2.newBuilder();
              if (hasCentroid()) {
                subBuilder.mergeFrom(getCentroid());
              }
              input.readMessage(subBuilder, extensionRegistry);
              setCentroid(subBuilder.buildPartial());
              break;
            }
          }
        }
      }