//github地址:https://github.com/chenjie199234/Corelib/tree/master/id
var offset uint64 = uint64(time.Date(2020, 5, 21, 13, 14, 0, 0, time.UTC).Unix())var lasttime uint64
var serverid uint64
var rollback uint64//64bit data
//00000000000000000000000000000000         000                000000               0          0000000000000000000000
//----32 bit timestamp(second)------3bit time rollback-----6bit serverid----1bit maxid lock-------22bit id----------
//-----can support 136 years--------rollback 8 times/s---can support 60 servers----------can make 4,000,000+ ids in one second
var base uint64func init() {if serverid <= 0 || serverid >= 64 {panic("[ID.init]serviceid range wrong,only support [1-63]")}now := uint64(time.Now().Unix())templasttime := now - offsetif now <= offset || templasttime > (1<<32-1) {panic("[ID.init]server time wrong")}lasttime = templasttimebase = getlasttime() + getrollback() + getserverid()go func() {tker := time.NewTicker(200 * time.Millisecond)for {<-tker.Cnow = uint64(time.Now().Unix())templasttime = now - offsetif now <= offset || templasttime > (1<<32-1) {panic("[ID.init]server time wrong")}if templasttime < lasttime {rollback++fmt.Printf("[ID.init]server time rollback,old time:%d current time:%d rollback:%dn", lasttime, templasttime, rollback&7)}if lasttime != templasttime {lasttime = templasttimebase = getlasttime() + getrollback() + getserverid()}}}()
}
func getlasttime() uint64 {return lasttime << 32
}
func getrollback() uint64 {return (rollback & 7) << 29
}
func getserverid() uint64 {return serverid << 23
}func GetId() (uint64,error) {if (base & (1 << 22)) > 0 {return 0, fmt.Errorf("[ID.GetId]max id used up")}newid := atomic.AddUint64(&base, 1)if (newid & (1 << 22)) > 0 {return 0, fmt.Errorf("[ID.GetId]max id used up")}return newid, nil
}