内存表增加一列
bool swoole_table->column(string $name, int $type, int $size = 0);swoole_table::TYPE_INT默认为4个字节，可以设置1，2，4，8一共4种长度
swoole_table::TYPE_STRING设置后，设置的字符串不能超过此长度
swoole_table::TYPE_FLOAT会占用8个字节的内存
非x86环境需要内存对齐
/*
Linux raspberrypi 4.4.34-v7+ #930 SMP Wed Nov 23 15:20:41 GMT 2016 armv7l GNU/Linux
gcc version 4.9.2 (Raspbian 4.9.2-10)
model name : ARMv7 Processor rev 4 (v7l)
BogoMIPS : 76.80
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4
*/
//bad
use Swoole\Table;
$table = new \Swoole\Table(8);
$table->column('data',Table::TYPE_STRING, 1);
$table->create();
$table->set(1,[]);
var_dump($table->get(1));
//result: Bus error
//good
use Swoole\Table;
$table = new \Swoole\Table(8);
$table->column('data',Table::TYPE_STRING, 1);
$table->column('pad',Table::TYPE_STRING, 1);
$table->create();
$table->set(1,[]);
var_dump($table->get(1));
/*
result
array(2) {
["data"]=>
string(0) ""
["pad"]=>
string(0) ""
}
*/