Method apply

bolt/expression/tests/ExprTest.cpp:794–824

class PlusConstantFunction : public exec::VectorFunction {
 public:
  explicit PlusConstantFunction(int32_t addition) : addition_(addition) {}

  void apply(
      const SelectivityVector& rows,
      std::vector<VectorPtr>& args,
      const TypePtr& /* outputType */,
      exec::EvalCtx& context,
      VectorPtr& result) const override {
    BOLT_CHECK_EQ(args.size(), 1);

    auto& arg = args[0];

    // The argument may be flat or constant.
    BOLT_CHECK(arg->isFlatEncoding() || arg->isConstantEncoding());

    BaseVector::ensureWritable(rows, INTEGER(), context.pool(), result);

    auto flatResult = result->asFlatVector<int32_t>();
    auto rawResult = flatResult->mutableRawValues();

    flatResult->clearNulls(rows);

    if (arg->isConstantEncoding()) {
      auto value = arg->as<ConstantVector<int32_t>>()->valueAt(0);
      rows.applyToSelected(
          [&](auto row) { rawResult[row] = value + addition_; });
    } else {
      auto* rawInput = arg->as<FlatVector<int32_t>>()->rawValues();

      rows.applyToSelected(
          [&](auto row) { rawResult[row] = rawInput[row] + addition_; });
    }
  }