Class Dynamic_array

sql/sql_array.h:105–213

*/

template <class Elem> class Dynamic_array
{
  DYNAMIC_ARRAY  array;
public:
  Dynamic_array(uint prealloc=16, uint increment=16)
  {
    init(prealloc, increment);
  }

  void init(uint prealloc=16, uint increment=16)
  {
    my_init_dynamic_array(&array, sizeof(Elem), prealloc, increment);
  }

  /**
     @note Though formally this could be declared "const" it would be
     misleading at it returns a non-const pointer to array's data.
  */
  Elem& at(int idx)
  {
    return *(((Elem*)array.buffer) + idx);
  }
  /// Const variant of at(), which cannot change data
  const Elem& at(int idx) const
  {
    return *(((Elem*)array.buffer) + idx);
  }

  /// @returns pointer to first element; undefined behaviour if array is empty
  Elem *front()
  {
    DBUG_ASSERT(array.elements >= 1);
    return (Elem*)array.buffer;
  }

  /// @returns pointer to first element; undefined behaviour if array is empty
  const Elem *front() const
  {
    DBUG_ASSERT(array.elements >= 1);
    return (const Elem*)array.buffer;
  }

  /// @returns pointer to last element; undefined behaviour if array is empty.
  Elem *back()
  {
    DBUG_ASSERT(array.elements >= 1);
    return ((Elem*)array.buffer) + (array.elements - 1);
  }

  /// @returns pointer to last element; undefined behaviour if array is empty.
  const Elem *back() const
  {
    DBUG_ASSERT(array.elements >= 1);
    return ((const Elem*)array.buffer) + (array.elements - 1);
  }

  /**
     @retval false ok