├── go.mod
├── README.md
├── .gitignore
├── goid_test.go
├── LICENSE
└── goid.go


/go.mod:
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1 | module github.com/fn-code/goid
2 | 
3 | go 1.12
4 | 


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/README.md:
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1 | # goid
2 | goid is generate 20 byte random id inspired from firebase realtime id
3 | 


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/.gitignore:
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 1 | # Binaries for programs and plugins
 2 | *.exe
 3 | *.exe~
 4 | *.dll
 5 | *.so
 6 | *.dylib
 7 | 
 8 | # Test binary, build with `go test -c`
 9 | *.test
10 | 
11 | # Output of the go coverage tool, specifically when used with LiteIDE
12 | *.out
13 | 


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/goid_test.go:
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 1 | package goid
 2 | 
 3 | import (
 4 | 	"testing"
 5 | )
 6 | 
 7 | var lastId GID
 8 | 
 9 | func TestNew(t *testing.T) {
10 | 	for i := 0; i < 100000; i++ {
11 | 		new := New()
12 | 		if new.String() == lastId.String() {
13 | 			t.Errorf("error generate unique new: %v - last: %v", new, lastId)
14 | 		}
15 | 		lastId = new
16 | 	}
17 | }
18 | 
19 | func BenchmarkNew(b *testing.B) {
20 | 	for i := 0; i < b.N; i++ {
21 | 		New()
22 | 	}
23 | }
24 | 


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/LICENSE:
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 1 | MIT License
 2 | 
 3 | Copyright (c) 2018 Fun Code
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy
 6 | of this software and associated documentation files (the "Software"), to deal
 7 | in the Software without restriction, including without limitation the rights
 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9 | copies of the Software, and to permit persons to whom the Software is
10 | furnished to do so, subject to the following conditions:
11 | 
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 | 
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 | SOFTWARE.
22 | 


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/goid.go:
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 1 | package goid
 2 | 
 3 | import (
 4 | 	"math/rand"
 5 | 	"time"
 6 | )
 7 | 
 8 | const (
 9 | 	// Base64 web-safe chars, but ordered by ASCII.
10 | 	charID = "-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz"
11 | )
12 | 
13 | // GID is convert byte to string
14 | type GID string
15 | 
16 | var lastTime int64
17 | 
18 | // New is used for generate 20 random id base on base64 web save chars
19 | func New() GID {
20 | 	id := [20]byte{}
21 | 	timeMs := time.Now().UTC().UnixNano() / 1e6
22 | 	lastID := generateLastID(timeMs, lastTime)
23 | 
24 | 	lastTime = timeMs
25 | 	// generate last 12 byte of id
26 | 	for i := 0; i < 12; i++ {
27 | 		id[(len(id)-1)-i] = charID[lastID[i]]
28 | 	}
29 | 
30 | 	// Genererate first 8 byte of id
31 | 	for i := 7; i >= 0; i-- {
32 | 		n := int(timeMs % 64)
33 | 		id[i] = charID[n]
34 | 		timeMs = timeMs / 64
35 | 	}
36 | 	return GID(id[:])
37 | }
38 | 
39 | func (s GID) String() string {
40 | 	return string(s)
41 | }
42 | 
43 | var lastIDS [12]int
44 | 
45 | func generateLastID(timeMs, lastTime int64) [12]int {
46 | 	var randNumber *rand.Rand
47 | 	randNumber = rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
48 | 	if timeMs == lastTime {
49 | 		// incremen last rand id
50 | 		lastIDS = inLastRandID(lastIDS)
51 | 	} else {
52 | 		for i := 0; i < len(lastIDS); i++ {
53 | 			lastIDS[i] = randNumber.Intn(64)
54 | 		}
55 | 	}
56 | 	return lastIDS
57 | }
58 | 
59 | func inLastRandID(r [12]int) [12]int {
60 | 	for i := 0; i < 12; i++ {
61 | 		r[i]++
62 | 		if r[i] < 64 {
63 | 			break
64 | 		}
65 | 		r[i] = 0
66 | 	}
67 | 	return r
68 | }
69 | 


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