checkdigit

README

checkdigit

Source

エキスパートたちのGo言語 一流のコードから応用力を学ぶ
1.5 複数のアルゴリズムに対応したチェックディジットライブラリ

Documentation

Index

• Variables
• type Generator
• type Provider
  • func NewJAN13() Provider
  • func NewLuhn() Provider
• type Verifier

Examples

• NewLuhn

Variables

var ErrInvalidArgument = errors.New("checkdigit: invalid argument")

ErrInvalidArgument is happening when given the wrong argument.

Types

type Generator

type Generator interface {
	Generate(seed string) (int, error)
}

A Generator generates a check digit by implemented algorithm or calculator.

type Provider

type Provider interface {
	Verifier
	Generator
}

func NewJAN13

func NewJAN13() Provider

NewJAN13 returns a new Provider that implemented GTIN-13 with position correction calculator.

func NewLuhn

func NewLuhn() Provider

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/178inaba/tech-playground/checkdigit"
)

func main() {
	p := checkdigit.NewLuhn()

	const seed = "411111111111111"
	cd, err := p.Generate(seed)
	if err != nil {
		log.Fatalln("failed to generate check digit")
	}

	ok := p.Verify(seed + strconv.Itoa(cd))
	fmt.Printf("seed: %s, check digit: %d, verify: %t\n", seed, cd, ok)

}

Output:

seed: 411111111111111, check digit: 1, verify: true

type Verifier

type Verifier interface {
	Verify(code string) bool
}

A Verifier is verifying to code by implemented algorithm or calculator.