jxskiss / base62 Goto Github PK

View Code? Open in Web Editor NEW

77.0 3.0 5.0 19 KB

Compact and high performace implementation of base62 algorithm for Golang.

License: MIT License

Go 100.00%

golang go base62

base62's People

Contributors

Stargazers

Watchers

Forkers

xissy rickb777 fufuok

base62's Issues

Why the unsafe pointer reference?

base62/base62.go

Line 222 in 9b9fb35

return *(*string)(unsafe.Pointer(&b))

Wouldn't this be the same as return string(bytes) and return []byte(str)?

Question to make sense of the algorithm

If I'm not mistaken the masks used are for the algorithm presuming it's reading the input string backwards?

Was trying to implement this in c and I'm still having trouble. I got curious if the algorithm can be "flipped" the other way around. Instead of reading what I'm assuming is 6 bits from the end, having it read 6 bits from the front. I think this changes the mask from (63 & 62 & 31 & 30) to (63 & 62 & 61 & 60)?

Incorrect Encoding of `ffffffffffffffffffffffffffffffff`

Compare the output from jxskiss/base62 to that from keys-pub/keys/encoding:

package main

import (
	"fmt"

	"github.com/jxskiss/base62"
	"github.com/keys-pub/keys/encoding"
)

func main() {
	id := []byte{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255}
	fmt.Println(base62.EncodeToString(id[:]))
	fmt.Println(encoding.EncodeBase62(id[:]))
}

Output:

fffffffffffffffffffffffffH
7n42DGM5Tflk9n8mt7Fhc7

I believe keys-pub/keys/encoding is correct and jxskiss/base62 is not.

Does not agree with Saltpack / GMP

Reference Strings

For reference, I here's the output of this library (jxskiss) compared to saltpack, which seems to also be compatible with the GMP and GnuPG Base62 implementations, even when using the same alphabet:

enc := base62.NewEncoding("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")

Raw     : Hello, 世界 (13 bytes)
Base64  : SGVsbG8sIOS4lueVjA (18 chars)
jxskiss : CMvvMYBvWmoRinMP81 (18 chars)
saltpack: 1wJfrzvdbuFbL65vcS (18 chars)

Raw     : Hello World (11 bytes)
Base64  : SGVsbG8gV29ybGQ (15 chars)
jxskiss : ancSlT58ln6RbX4 (15 chars)
saltpack: 73XpUgyMwkGr29M (15 chars)

Raw     : [0] (1 bytes)
Base64  : AA (2 chars)
jxskiss : 00 (2 chars)
saltpack: 00 (2 chars)

Raw     : [0 0 0 0 0 0 0 0 0 0 0 0] (12 bytes)
Base64  : AAAAAAAAAAAAAAAA (16 chars)
jxskiss : 0000000000000000 (16 chars)
saltpack: 00000000000000000 (17 chars)

Raw     : [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] (24 bytes)
Base64  : AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA (32 chars)
jxskiss : 00000000000000000000000000000000 (32 chars)
saltpack: 000000000000000000000000000000000 (33 chars)

Raw     : [0 0 0 0 255 255 255 255] (8 bytes)
Base64  : AAAAAP____8 (11 chars)
jxskiss : VVVVVV300000 (12 chars)
saltpack: 000004gfFC3 (11 chars)

Raw     : [255 255 255 255 0 0 0 0] (8 bytes)
Base64  : _____wAAAAA (11 chars)
jxskiss : 00000yVVVVV7 (12 chars)
saltpack: LygHZwPV2MC (11 chars)

As you can see, it's not just a matter of the output being reversed, but the character sequences are entirely different.

Test Output Reference

package main

import (
	"encoding/base64"
	"fmt"

	"github.com/jxskiss/base62"
	"github.com/keybase/saltpack/encoding/basex"
)

func main() {
	enc := base62.NewEncoding("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")

	for _, src := range [][]byte{
		[]byte("Hello, 世界"),
		[]byte("Hello World"),
		{0},
		{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 255, 255, 255, 255},
		{255, 255, 255, 255, 0, 0, 0, 0},
	} {
		b62 := enc.Encode(src)
		b64 := base64.RawURLEncoding.EncodeToString(src)
		sp62 := basex.Base62StdEncoding.EncodeToString(src)

		if src[0] == 0x0 || src[1] == 255 {
			fmt.Printf("Raw     : %v (%d bytes)\n", src, len(src))
		} else {
			fmt.Printf("Raw     : %v (%d bytes)\n", string(src), len(src))
		}
		fmt.Printf("Base64  : %s (%d chars)\n", b64, len(b64))
		fmt.Printf("jxskiss : %s (%d chars)\n", b62, len(b62))
		fmt.Printf("saltpack: %s (%d chars)\n", sp62, len(sp62))
		fmt.Println("")
	}
}

Recommend Projects

React

A declarative, efficient, and flexible JavaScript library for building user interfaces.
Vue.js

🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
Typescript

TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
TensorFlow

An Open Source Machine Learning Framework for Everyone
Django

The Web framework for perfectionists with deadlines.
Laravel

A PHP framework for web artisans
D3

Bring data to life with SVG, Canvas and HTML. 📊📈🎉

Recommend Topics

javascript

JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
web

Some thing interesting about web. New door for the world.
server

A server is a program made to process requests and deliver data to clients.
Machine learning

Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Visualization

Some thing interesting about visualization, use data art
Game

Some thing interesting about game, make everyone happy.

Recommend Org

Facebook

We are working to build community through open source technology. NB: members must have two-factor auth.
Microsoft

Open source projects and samples from Microsoft.
Google

Google ❤️ Open Source for everyone.
Alibaba

Alibaba Open Source for everyone
D3

Data-Driven Documents codes.
Tencent

China tencent open source team.