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// to you under the Apache License, Version 2.0 (the
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#ifndef IMPALA_EXPRS_VALID_TUPLE_ID_H_
#define IMPALA_EXPRS_VALID_TUPLE_ID_H_

#include "exprs/scalar-expr.h"

namespace impala {

class TExprNode;

/// Returns the tuple id of the single non-NULL tuple in the input row.
/// Valid input rows must have exactly one non-NULL tuple.
class ValidTupleIdExpr : public ScalarExpr {
 public:
  static const char* LLVM_CLASS_NAME;

 protected:
  friend class ScalarExpr;

  explicit ValidTupleIdExpr(const TExprNode& node);

  virtual Status Init(
      const RowDescriptor& row_desc, bool is_entry_point, RuntimeState* state) override;
  virtual Status GetCodegendComputeFnImpl(
      LlvmCodeGen* codegen, llvm::Function** fn) override WARN_UNUSED_RESULT;
  virtual std::string DebugString() const override;

  virtual IntVal GetIntValInterpreted(
      ScalarExprEvaluator*, const TupleRow*) const override;

 private:
  /// Maps from tuple index in the row to its corresponding tuple id.
  std::vector<TupleId> tuple_ids_;

  /// Returns the number of tuples in 'row' that are non-null. Used for debugging.
  static int ComputeNonNullCount(const TupleRow* row, int num_tuples);

  /// Returns true if the tuple of the row at the specified index is non-null.
  /// Called by Codegen.
  static bool IsTupleFromRowNonNull(const TupleRow* row, int index);
};

} // namespace impala

#endif