checkdigit

README

checkdigit

About

Provide check digit algorithms and calculators written by Go.

Provided methods

Algorithms

• Luhn
• Verhoeff
• Damm

Calculators

• ISBN-10
• ISBN-13
• EAN-8
• EAN-13
• JAN-8
• JAN-13
• ITF
• UPC
• SSCC

Usage

See examples.

License

Released under the MIT License.

Documentation

Overview

Package checkdigit provides check digit algorithms and calculators written by Go.

Index

• Variables
• type Generator
• type Provider
  • func NewDamm() Provider
  • func NewEAN13() Provider
  • func NewEAN8() Provider
  • func NewISBN10() Provider
  • func NewISBN13() Provider
  • func NewITF() Provider
  • func NewJAN13() Provider
  • func NewJAN8() Provider
  • func NewLuhn() Provider
  • func NewSSCC() Provider
  • func NewUPC() Provider
  • func NewVerhoeff() Provider
• type Verifier

Examples

• NewDamm
• NewEAN13
• NewEAN8
• NewISBN10
• NewISBN13
• NewITF
• NewJAN13
• NewJAN8
• NewLuhn
• NewSSCC
• NewUPC
• NewVerhoeff

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
}

A Provider has Verifier and Generator interfaces.

func NewDamm

func NewDamm() Provider

NewDamm returns a new Provider that implemented the Damm algorithm.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

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

	const seed = "572"
	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: 572, check digit: 4, verify: true

func NewEAN13

func NewEAN13() Provider

NewEAN13 returns a new Provider that implemented GTIN-13 with position correction calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewEAN13()

	const seed = "590123412345"
	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: 590123412345, check digit: 7, verify: true

func NewEAN8

func NewEAN8() Provider

NewEAN8 returns a new Provider that implemented GTIN-8 with position correction calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewEAN8()

	const seed = "9638507"
	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: 9638507, check digit: 4, verify: true

func NewISBN10

func NewISBN10() Provider

NewISBN10 returns a new Provider that implemented modulus 11 weight 10 to 2 calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewISBN10()

	const seed = "155860832"
	cd, err := p.Generate(seed)
	if err != nil {
		log.Fatalln("failed to generate check digit")
	}

	digit := "X"
	if cd != 10 {
		digit = strconv.Itoa(cd)
	}

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

}

Output:

seed: 155860832, check digit: X, verify: true

func NewISBN13

func NewISBN13() Provider

NewISBN13 returns a new Provider that implemented modulus 10 weight 3 calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewISBN13()

	const seed = "978000271217"
	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: 978000271217, check digit: 0, verify: true

func NewITF

func NewITF() Provider

NewITF returns a new Provider that implemented GTIN-14 calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

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

	const seed = "1456995111617"
	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: 1456995111617, check digit: 6, verify: true

func NewJAN13

func NewJAN13() Provider

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

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewJAN13()

	const seed = "456995111617"
	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: 456995111617, check digit: 9, verify: true

func NewJAN8

func NewJAN8() Provider

NewJAN8 returns a new Provider that implemented GTIN-8 with position correction calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

func main() {
	p := checkdigit.NewJAN8()

	const seed = "4996871"
	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: 4996871, check digit: 2, verify: true

func NewLuhn

func NewLuhn() Provider

NewLuhn returns a new Provider that implemented the Luhn algorithm.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/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

func NewSSCC

func NewSSCC() Provider

NewSSCC returns a new Provider that implemented GTIN-18 calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

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

	const seed = "04569951110000001"
	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: 04569951110000001, check digit: 6, verify: true

func NewUPC

func NewUPC() Provider

NewUPC returns a new Provider that implemented GTIN-12 with position correction calculator.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

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

	const seed = "01234567890"
	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: 01234567890, check digit: 5, verify: true

func NewVerhoeff

func NewVerhoeff() Provider

NewVerhoeff returns a new Provider that implemented the Verhoeff algorithm.

Example

package main

import (
	"fmt"
	"log"
	"strconv"

	"github.com/osamingo/checkdigit"
)

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

	const seed = "236"
	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: 236, check digit: 3, verify: true

type Verifier

type Verifier interface {
	Verify(code string) bool
}

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