types/VarCharType.hpp

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 **/

#ifndef QUICKSTEP_TYPES_VAR_CHAR_TYPE_HPP_
#define QUICKSTEP_TYPES_VAR_CHAR_TYPE_HPP_

#include <cstddef>
#include <cstdio>
#include <string>

#include "types/Type.hpp"
#include "types/Type.pb.h"
#include "types/TypeID.hpp"
#include "types/TypedValue.hpp"
#include "utility/Macros.hpp"

namespace quickstep {

/** \addtogroup Types
 *  @{
 */

/**
 * @brief A type representing a variable-length ASCII string.
 *
 * @note VarChar strings are ALWAYS represented with a null-terminator
 *       character. This means that the VARCHAR(X) type requires from 1 to X+1
 *       bytes of storage, depending on string length.
 **/
class VarCharType : public AsciiStringSuperType {
 public:
  /**
   * @brief Get a reference to the non-nullable singleton instance of this Type
   *        for the specified length.
   *
   * @param length The length parameter of the VarCharType.
   * @return A reference to the non-nullable singleton instance of this Type
   *         for the specified length.
   **/
  static const VarCharType& InstanceNonNullable(const std::size_t length);

  /**
   * @brief Get a reference to the nullable singleton instance of this Type for
   *        the specified length.
   *
   * @param length The length parameter of the VarCharType.
   * @return A reference to the nullable singleton instance of this Type for
   *         the specified length.
   **/
  static const VarCharType& InstanceNullable(const std::size_t length);

  /**
   * @brief Get a reference to the singleton instance of this Type for the
   *        specified length and nullability.
   *
   * @param length The length parameter of the VarCharType.
   * @param nullable Whether to get the nullable version of this Type.
   * @return A reference to the singleton instance of this Type for the
   *         specified length and nullability.
   **/
  static const VarCharType& Instance(const std::size_t length, const bool nullable) {
    if (nullable) {
      return InstanceNullable(length);
    } else {
      return InstanceNonNullable(length);
    }
  }

  /**
   * @brief Get a reference to the singleton instance of this Type described
   *        by the given Protocol Buffer serialization.
   *
   * @param type The serialized Protocol Buffer representation of the desired
   *        VarCharType.
   * @return A reference to the singleton instance of this Type for the given
   *         Protocol Buffer.
   **/
  static const VarCharType& InstanceFromProto(const serialization::Type &type);

  /**
   * @brief Generate a serialized Protocol Buffer representation of this Type.
   *
   * @return The serialized Protocol Buffer representation of this Type.
   **/
  serialization::Type getProto() const override;

  const Type& getNullableVersion() const override {
    return InstanceNullable(length_);
  }

  const Type& getNonNullableVersion() const override {
    return InstanceNonNullable(length_);
  }

  /**
   * @note Includes an extra byte for a terminating null character.
   **/
  std::size_t estimateAverageByteLength() const override;

  bool isSafelyCoercibleFrom(const Type& original_type) const override;

  bool isSubsumedBy(const Type &original_type) const override;

  std::string getName() const override;

  int getPrintWidth() const override {
    return length_;
  }

  std::string printValueToString(const TypedValue &value) const override;

  void printValueToFile(const TypedValue &value,
                        FILE *file,
                        const int padding = 0) const override;

  bool parseValueFromString(const std::string &value_string,
                            TypedValue *value) const override;

  TypedValue coerceValue(const TypedValue &original_value,
                         const Type &original_type) const override;

 private:
  VarCharType(const std::size_t length, const bool nullable)
      : AsciiStringSuperType(kVarChar, nullable, 1, length + 1, length) {
  }

  template <bool nullable_internal>
  static const VarCharType& InstanceInternal(const std::size_t length);

  DISALLOW_COPY_AND_ASSIGN(VarCharType);
};

/** @} */

}  // namespace quickstep

#endif  // QUICKSTEP_TYPES_VAR_CHAR_TYPE_HPP_