value.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. */
 
//
// Created by Wangyunlai 2023/6/27
//
 
#pragma once
 
#include "common/lang/string.h"
#include "common/lang/memory.h"
#include "common/type/attr_type.h"
#include "common/type/data_type.h"
 
class Value final
{
public:
  friend class DataType;
  friend class IntegerType;
  friend class FloatType;
  friend class BooleanType;
  friend class CharType;
  friend class VectorType;
 
  Value() = default;
 
  ~Value() { reset(); }
 
  Value(AttrType attr_type, char *data, int length = 4) : attr_type_(attr_type) { this->set_data(data, length); }
 
  explicit Value(int val);
  explicit Value(float val);
  explicit Value(bool val);
  explicit Value(const char *s, int len = 0);
 
  Value(const Value &other);
  Value(Value &&other);
 
  Value &operator=(const Value &other);
  Value &operator=(Value &&other);
 
  void reset();
 
  static RC add(const Value &left, const Value &right, Value &result)
  {
    return DataType::type_instance(result.attr_type())->add(left, right, result);
  }
 
  static RC subtract(const Value &left, const Value &right, Value &result)
  {
    return DataType::type_instance(result.attr_type())->subtract(left, right, result);
  }
 
  static RC multiply(const Value &left, const Value &right, Value &result)
  {
    return DataType::type_instance(result.attr_type())->multiply(left, right, result);
  }
 
  static RC divide(const Value &left, const Value &right, Value &result)
  {
    return DataType::type_instance(result.attr_type())->divide(left, right, result);
  }
 
  static RC negative(const Value &value, Value &result)
  {
    return DataType::type_instance(result.attr_type())->negative(value, result);
  }
 
  static RC cast_to(const Value &value, AttrType to_type, Value &result)
  {
    return DataType::type_instance(value.attr_type())->cast_to(value, to_type, result);
  }
 
  void set_type(AttrType type) { this->attr_type_ = type; }
  void set_data(char *data, int length);
  void set_data(const char *data, int length) { this->set_data(const_cast<char *>(data), length); }
  void set_value(const Value &value);
  void set_boolean(bool val);
 
  string to_string() const;
 
  int compare(const Value &other) const;
 
  const char *data() const;
 
  int      length() const { return length_; }
  AttrType attr_type() const { return attr_type_; }
 
public:
  int    get_int() const;
  float  get_float() const;
  string get_string() const;
  bool   get_boolean() const;
 
private:
  void set_int(int val);
  void set_float(float val);
  void set_string(const char *s, int len = 0);
  void set_string_from_other(const Value &other);
 
private:
  AttrType attr_type_ = AttrType::UNDEFINED;
  int      length_    = 0;
 
  union Val
  {
    int32_t int_value_;
    float   float_value_;
    bool    bool_value_;
    char   *pointer_value_;
  } value_ = {.int_value_ = 0};
 
  bool own_data_ = false;
};