Function mem_root_dynamic_array_init

mysys/array.c:420–463

}

int mem_root_dynamic_array_init(MEM_ROOT *current_mem_root,
                                PSI_memory_key psi_key,
                                MEM_ROOT_DYNAMIC_ARRAY *array,
                                size_t element_size, void *init_buffer,
                                size_t init_alloc, size_t alloc_increment,
                                myf my_flags)
{
  DBUG_ENTER("init_mem_root_dynamic_array");

  array->elements=0;
  array->max_element=init_alloc;
  array->alloc_increment=alloc_increment;
  array->size_of_element=element_size;
  array->m_psi_key= psi_key;
  array->malloc_flags= my_flags;
  array->mem_root= current_mem_root;

  if ((array->buffer= (uchar*)init_buffer))
  {
    array->malloc_flags|= MY_INIT_BUFFER_USED;
    memset(array->buffer, 0, array->size_of_element*array->max_element);
    DBUG_RETURN(FALSE);
  }

  if (!alloc_increment && !(my_flags & MY_BUFFER_NO_RESIZE))
  {
    alloc_increment=MY_MAX((8192-MALLOC_OVERHEAD)/element_size,16);
    if (init_alloc > 8 && alloc_increment > init_alloc * 2)
      alloc_increment=init_alloc*2;
  }

  /*
    Since the dynamic array is usable even if allocation fails here malloc
    should not throw an error
  */
  if (init_alloc &&
      !(array->buffer= (uchar*) alloc_root(array->mem_root,
                                           array->size_of_element*
                                                 array->max_element)))
    array->max_element=0;
  memset(array->buffer, 0, array->size_of_element*array->max_element);

  DBUG_RETURN(FALSE);
}

void mem_root_dynamic_array_reset(MEM_ROOT_DYNAMIC_ARRAY *array)
{