MYSQL_FIELD *
unpack_fields(MYSQL *mysql, MYSQL_DATA *data,MEM_ROOT *alloc,uint fields,
	      my_bool default_value, uint server_capabilities)
{
  MYSQL_ROWS	*row;
  MYSQL_FIELD	*field,*result;
  ulong lengths[9];				/* Max of fields */
  DBUG_ENTER("unpack_fields");

  field= result= (MYSQL_FIELD*) alloc_root(alloc,
					   (uint) sizeof(*field)*fields);
  if (!result)
  {
    free_rows(data);				/* Free old data */
    set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
    DBUG_RETURN(0);
  }
  memset(field, 0, sizeof(MYSQL_FIELD)*fields);
  if (server_capabilities & CLIENT_PROTOCOL_41)
  {
    /* server is 4.1, and returns the new field result format */
    for (row=data->data; row ; row = row->next,field++)
    {
      uchar *pos;
      /* fields count may be wrong */
      DBUG_ASSERT((uint) (field - result) < fields);
      cli_fetch_lengths(&lengths[0], row->data, default_value ? 8 : 7);
      field->catalog=   strmake_root(alloc,(char*) row->data[0], lengths[0]);
      field->db=        strmake_root(alloc,(char*) row->data[1], lengths[1]);
      field->table=     strmake_root(alloc,(char*) row->data[2], lengths[2]);
      field->org_table= strmake_root(alloc,(char*) row->data[3], lengths[3]);
      field->name=      strmake_root(alloc,(char*) row->data[4], lengths[4]);
      field->org_name=  strmake_root(alloc,(char*) row->data[5], lengths[5]);

      field->catalog_length=	lengths[0];
      field->db_length=		lengths[1];
      field->table_length=	lengths[2];
      field->org_table_length=	lengths[3];
      field->name_length=	lengths[4];
      field->org_name_length=	lengths[5];

      /* Unpack fixed length parts */
      if (lengths[6] != 12)
      {
        /* malformed packet. signal an error. */
        free_rows(data);			/* Free old data */
        set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate);
        DBUG_RETURN(0);
      }

      pos= (uchar*) row->data[6];
      field->charsetnr= uint2korr(pos);
      field->length=	(uint) uint4korr(pos+2);
      field->type=	(enum enum_field_types) pos[6];
      field->flags=	uint2korr(pos+7);
      field->decimals=  (uint) pos[9];

      if (IS_NUM(field->type))
        field->flags|= NUM_FLAG;
      if (default_value && row->data[7])
      {
        field->def=strmake_root(alloc,(char*) row->data[7], lengths[7]);
	field->def_length= lengths[7];
      }
      else
        field->def=0;
      field->max_length= 0;
    }
  }
#ifndef DELETE_SUPPORT_OF_4_0_PROTOCOL
  else
  {
    /* old protocol, for backward compatibility */
    for (row=data->data; row ; row = row->next,field++)
    {
      cli_fetch_lengths(&lengths[0], row->data, default_value ? 6 : 5);
      field->org_table= field->table=  strdup_root(alloc,(char*) row->data[0]);
      field->name=   strdup_root(alloc,(char*) row->data[1]);
      field->length= (uint) uint3korr(row->data[2]);
      field->type=   (enum enum_field_types) (uchar) row->data[3][0];

      field->catalog=(char*)  "";
      field->db=     (char*)  "";
      field->catalog_length= 0;
      field->db_length= 0;
      field->org_table_length=	field->table_length=	lengths[0];
      field->name_length=	lengths[1];

      if (server_capabilities & CLIENT_LONG_FLAG)
      {
        field->flags=   uint2korr(row->data[4]);
        field->decimals=(uint) (uchar) row->data[4][2];
      }
      else
      {
        field->flags=   (uint) (uchar) row->data[4][0];
        field->decimals=(uint) (uchar) row->data[4][1];
      }
      if (IS_NUM(field->type))
        field->flags|= NUM_FLAG;
      if (default_value && row->data[5])
      {
        field->def=strdup_root(alloc,(char*) row->data[5]);
	field->def_length= lengths[5];
      }
      else
        field->def=0;
      field->max_length= 0;
    }
  }
#endif /* DELETE_SUPPORT_OF_4_0_PROTOCOL */
  free_rows(data);				/* Free old data */
  DBUG_RETURN(result);