aggregate_vec_physical_operator.h

/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
miniob is licensed under Mulan PSL v2.
You can use this software according to the terms and conditions of the Mulan PSL v2.
You may obtain a copy of Mulan PSL v2 at:
         http://license.coscl.org.cn/MulanPSL2
THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
See the Mulan PSL v2 for more details. */
 
#pragma once
 
#include "sql/operator/physical_operator.h"
 
class AggregateVecPhysicalOperator : public PhysicalOperator
{
public:
  AggregateVecPhysicalOperator(vector<Expression *> &&expressions);
 
  virtual ~AggregateVecPhysicalOperator() = default;
 
  PhysicalOperatorType type() const override { return PhysicalOperatorType::AGGREGATE_VEC; }
 
  RC open(Trx *trx) override;
  RC next(Chunk &chunk) override;
  RC close() override;
 
private:
  template <class STATE, typename T>
  void update_aggregate_state(void *state, const Column &column);
 
  template <class STATE, typename T>
  void append_to_column(void *state, Column &column)
  {
    STATE *state_ptr = reinterpret_cast<STATE *>(state);
    column.append_one((char *)&state_ptr->value);
  }
 
private:
  class AggregateValues
  {
  public:
    AggregateValues() = default;
 
    void insert(void *aggr_value) { data_.push_back(aggr_value); }
 
    void *at(size_t index)
    {
      ASSERT(index <= data_.size(), "index out of range");
      return data_[index];
    }
 
    size_t size() { return data_.size(); }
    ~AggregateValues()
    {
      for (auto &aggr_value : data_) {
        free(aggr_value);
        aggr_value = nullptr;
      }
    }
 
  private:
    vector<void *> data_;
  };
  vector<Expression *> aggregate_expressions_;  
  vector<Expression *> value_expressions_;
  Chunk                chunk_;
  Chunk                output_chunk_;
  AggregateValues      aggr_values_;
};