├── README.md
└── idworker.go


/README.md:
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 1 | # go-id-worker
 2 | 
 3 | IdWorker in golang.
 4 | 
 5 | [HTTP Interface Open source project (https://github.com/gitstliu/idservice)](https://github.com/gitstliu/idservice)
 6 | 
 7 | 
 8 | go-id-worker is an id creator, for generating a global unique id. The type of id is int64.
 9 | 
10 | ## You can get it like this.
11 | ```
12 | go get "github.com/gitstliu/go-id-worker"
13 | ```
14 | 
15 | ## And import it like this.
16 | ```
17 | import (
18 |   "github.com/gitstliu/go-id-worker"
19 | )
20 | ```
21 | 
22 | ## Create and use an idWorker like this.
23 | ```
24 | currWoker := &idworker.IdWorker{} 
25 | currWoker.InitIdWorker(1000, 1)
26 | newId , newIdErr:= currWoker.NexiId()
27 | ......
28 | ```
29 | 
30 | 
31 | 
32 | 
33 | 	
34 | 


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/idworker.go:
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 1 | package idworker
 2 | 
 3 | import (
 4 | 	"errors"
 5 | 	"fmt"
 6 | 	"sync"
 7 | 	"time"
 8 | )
 9 | 
10 | type IdWorker struct {
11 | 	startTime             int64
12 | 	workerIdBits          uint
13 | 	datacenterIdBits      uint
14 | 	maxWorkerId           int64
15 | 	maxDatacenterId       int64
16 | 	sequenceBits          uint
17 | 	workerIdLeftShift     uint
18 | 	datacenterIdLeftShift uint
19 | 	timestampLeftShift    uint
20 | 	sequenceMask          int64
21 | 	workerId              int64
22 | 	datacenterId          int64
23 | 	sequence              int64
24 | 	lastTimestamp         int64
25 | 	signMask              int64
26 | 	idLock                *sync.Mutex
27 | }
28 | 
29 | func (this *IdWorker) InitIdWorker(workerId, datacenterId int64) error {
30 | 
31 | 	var baseValue int64 = -1
32 | 	this.startTime = 1463834116272
33 | 	this.workerIdBits = 5
34 | 	this.datacenterIdBits = 5
35 | 	this.maxWorkerId = baseValue ^ (baseValue << this.workerIdBits)
36 | 	this.maxDatacenterId = baseValue ^ (baseValue << this.datacenterIdBits)
37 | 	this.sequenceBits = 12
38 | 	this.workerIdLeftShift = this.sequenceBits
39 | 	this.datacenterIdLeftShift = this.workerIdBits + this.workerIdLeftShift
40 | 	this.timestampLeftShift = this.datacenterIdBits + this.datacenterIdLeftShift
41 | 	this.sequenceMask = baseValue ^ (baseValue << this.sequenceBits)
42 | 	this.sequence = 0
43 | 	this.lastTimestamp = -1
44 | 	this.signMask = ^baseValue + 1
45 | 
46 | 	this.idLock = &sync.Mutex{}
47 | 
48 | 	if this.workerId < 0 || this.workerId > this.maxWorkerId {
49 | 		return errors.New(fmt.Sprintf("workerId[%v] is less than 0 or greater than maxWorkerId[%v].", workerId, datacenterId))
50 | 	}
51 | 	if this.datacenterId < 0 || this.datacenterId > this.maxDatacenterId {
52 | 		return errors.New(fmt.Sprintf("datacenterId[%d] is less than 0 or greater than maxDatacenterId[%d].", workerId, datacenterId))
53 | 	}
54 | 	this.workerId = workerId
55 | 	this.datacenterId = datacenterId
56 | 	return nil
57 | }
58 | 
59 | func (this *IdWorker) NextId() (int64, error) {
60 | 	this.idLock.Lock()
61 | 	timestamp := time.Now().UnixNano()
62 | 	if timestamp < this.lastTimestamp {
63 | 		return -1, errors.New(fmt.Sprintf("Clock moved backwards.  Refusing to generate id for %d milliseconds", this.lastTimestamp-timestamp))
64 | 	}
65 | 
66 | 	if timestamp == this.lastTimestamp {
67 | 		this.sequence = (this.sequence + 1) & this.sequenceMask
68 | 		if this.sequence == 0 {
69 | 			timestamp = this.tilNextMillis()
70 | 			this.sequence = 0
71 | 		}
72 | 	} else {
73 | 		this.sequence = 0
74 | 	}
75 | 
76 | 	this.lastTimestamp = timestamp
77 | 
78 | 	this.idLock.Unlock()
79 | 
80 | 	id := ((timestamp - this.startTime) << this.timestampLeftShift) |
81 | 		(this.datacenterId << this.datacenterIdLeftShift) |
82 | 		(this.workerId << this.workerIdLeftShift) |
83 | 		this.sequence
84 | 
85 | 	if id < 0 {
86 | 		id = -id
87 | 	}
88 | 
89 | 	return id, nil
90 | }
91 | 
92 | func (this *IdWorker) tilNextMillis() int64 {
93 | 	timestamp := time.Now().UnixNano()
94 | 	if timestamp <= this.lastTimestamp {
95 | 		timestamp = time.Now().UnixNano() / int64(time.Millisecond)
96 | 	}
97 | 	return timestamp
98 | }
99 | 


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