Class BlockMap

src/basicio.cpp:592–650

! @brief Utility class provides the block mapping to the part of data. This avoids allocating a single contiguous block of memory to the big data. */

        a single contiguous block of memory to the big data.
 */
class BlockMap {
 public:
  //! the status of the block.
  enum blockType_e { bNone, bKnown, bMemory };
  //! @name Creators
  //@{
  //! Default constructor. the init status of the block is bNone.
  BlockMap() = default;

  //! Destructor. Releases all managed memory.
  ~BlockMap() {
    delete[] data_;
  }

  BlockMap(const BlockMap&) = delete;
  BlockMap& operator=(const BlockMap&) = delete;

  //! @brief Populate the block.
  //! @param source The data populate to the block
  //! @param num The size of data
  void populate(const byte* source, size_t num) {
    size_ = num;
    data_ = new byte[size_];
    type_ = bMemory;
    std::memcpy(data_, source, size_);
  }

  /*!
    @brief Change the status to bKnow. bKnow blocks do not contain the data,
          but they keep the size of data. This avoids allocating memory for parts
          of the file that contain image-date (non-metadata/pixel data) which never change in exiv2.
    @param num The size of the data
   */
  void markKnown(size_t num) {
    type_ = bKnown;
    size_ = num;
  }

  [[nodiscard]] bool isNone() const {
    return type_ == bNone;
  }

  [[nodiscard]] bool isKnown() const {
    return type_ == bKnown;
  }

  [[nodiscard]] byte* getData() const {
    return data_;
  }

  [[nodiscard]] size_t getSize() const {
    return size_;
  }

 private:
  blockType_e type_{bNone};
  byte* data_{nullptr};
  size_t size_{0};