base62

README

go-base62

Base62 encoder/decoder with golang. Uses the variant [A-Za-z0-9], but can be initialized with custom variant. The test cases covered the variant mentioned previously.

Installation

$ go get github.com/alextanhongpin/base62

Usage

Encode/Decode:

import base62 "github.com/alextanhongpin/base62"

func main() {
  fmt.Println(base62.Decode("golang")) // Outputs: 30847375997
  fmt.Println(base62.Encode(30847375997)) // Outputs: "golang"
}

Factory:

import base62 "github.com/alextanhongpin/base62"

func main() {
  b62 := base62.New(base62.DEFAULT_CHARS) // Or use your own variant
  fmt.Println(b62.Decode("golang")) // Outputs: 30847375997
  fmt.Println(b62.Encode(30847375997)) // Outputs: "golang"
}

Test Table

To test the encoding/decoding, we use the NATO Phonetic Alphabets. If the encoded values matches the decoded values, the test passes. There's a quickcheck test too to capture unexpected input.

Text	Decoded
Alfa	386411
Bravo	40145909
Charlie	201958818817
Delta	66642463
Echo	1305265
Foxtrot	379112811228
Golf	1828288
Hotel	128160920
India	142637661
Juliett	611630563254
Kilo	2758545
Lima	2996921
Mike	3235129
November	51675855992598
Oscar	232482994
Papa	3919667
Quebec	16276243687
Romeo	275897375
Sierra	17931255627
Tango	302117423
Uniform	1229975219171
Victor	20679184986
Whiskey	1338081975441
Xray	5890733
Yankee	23311959173
Zulu	6379599

Performance test

It's fast. Period.

$ go test -bench=. -benchmem -memprofile mem.out -cpuprofile cpu.out

Output:

goos: darwin
goarch: amd64
pkg: github.com/alextanhongpin/base62
BenchmarkEncode-4   	10000000	       200 ns/op	      64 B/op	       2 allocs/op
PASS
ok  	github.com/alextanhongpin/base62	2.378s

Documentation

Index

• Constants
• Variables
• func Decode(s string) uint64
• func Encode(in uint64) string
• type Factory
  • func New(chars [Base62]rune) *Factory
  • func (f *Factory) Decode(s string) uint64
  • func (f *Factory) Encode(in uint64) string

Constants

const Base62 uint64 = 62

Base62 represents the base62 const.

Variables

var (
	// Base62 character set, [A-Za-z0-9]. https://tools.ietf.org/html/rfc4648
	// We follow the orders similar to base64.
	// Note that there are several different variants in the web, such as
	// [0-9a-zA-Z] or [a-zA-Z0-9] and so on.
	DEFAULT_CHARS = [Base62]rune{
		'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
		'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
		'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
	}
)

Functions

func Decode

func Decode(s string) uint64

Decode attempts to convert a base 62 string back into an integer.

func Encode

func Encode(in uint64) string

Encode converts the given integer into a base 62 string.

Types

type Factory

type Factory struct {
	// contains filtered or unexported fields
}

Factory allows the creation of new base62 encoder/decoder with different variant of characters.

func New

func New(chars [Base62]rune) *Factory

New returns a new Factory with the given variant of characters.

func (*Factory) Decode

func (f *Factory) Decode(s string) uint64

Decode decodes the string back into integer.

func (*Factory) Encode

func (f *Factory) Encode(in uint64) string

Encode encodes the given integer into a base62 string.