Luhn Algorithm

The Luhn Algorithm is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, and others. This documentation provides an overview of the Luhn Algorithm implementation in PHP, including examples and use cases.

Installation

You can install the package via composer:

composer require designbycode/luhn-algorithm

Usage

Validating a Value

To validate a value using the Luhn Algorithm, create an instance of the LuhnAlgorithm class and call the isValid method:

$luhn = new LuhnAlgorithm();
$isValid = $luhn->isValid('79927398713'); // returns true

The isValid method returns true if the value is valid, and false otherwise.

Generating a Check Digit

To generate a check digit for a given value, call the generate method:

$luhn = new LuhnAlgorithm();
$generatedCheckDigit = $luhn->generate('7992739871'); // returns '79927398713'

The generate method returns the generated value including the check digit.

Stripping the Check Digit

To strip the check digit from a given value, call the withoutDigit method:

$luhn = new LuhnAlgorithm();
$valueWithoutDigit = $luhn->withoutDigit('79927398713'); // returns '7992739871'

The withoutDigit method returns the value without the check digit.

Validating and Suggesting a Check Digit

To validate a value and suggest the correct check digit if invalid, call the validateAndSuggest method:

$luhn = new LuhnAlgorithm();
$result = $luhn->validateAndSuggest('79927398712'); // returns ['isValid' => false, 'uggestedDigit' => '3']

The validateAndSuggest method returns an array containing isValid and suggestedDigit values.

Use Cases

Credit Card Validation

The Luhn Algorithm is commonly used to validate credit card numbers. You can use the isValid method to check if a credit card number is valid:

$luhn = new LuhnAlgorithm();
$isValid = $luhn->isValid('4242424242424242'); // returns true

IMEI Number Validation

The Luhn Algorithm can also be used to validate IMEI numbers. You can use the isValid method to check if an IMEI number is valid:

$luhn = new LuhnAlgorithm();
$isValid = $luhn->isValid('352656091234567'); // returns true

Generating Check Digits for IDs

You can use the generate method to generate check digits for various identification numbers, such as customer IDs or product codes:

$luhn = new LuhnAlgorithm();
$generatedCheckDigit = $luhn->generate('CUSTOMER1234'); // returns 'CUSTOMER12345'

Error Handling

The Luhn Algorithm implementation throws an InvalidArgumentException if the input value is empty or invalid. You can catch this exception to handle errors:

try {
    $luhn = new LuhnAlgorithm();
    $luhn->isValid('');
} catch (InvalidArgumentException $e) {
    echo 'Error: '. $e->getMessage();
}

Conclusion

The Luhn Algorithm implementation in PHP provides a simple and efficient way to validate and generate check digits for various identification numbers. By following this documentation, you can easily integrate the Luhn Algorithm into your PHP applications.

Testing

composer test

Changelog

Please see CHANGELOG for more information on what has changed recently.

Contributing

Please see CONTRIBUTING for details.

Security Vulnerabilities

Please review our security policy on how to report security vulnerabilities.

Credits

• claudemyburgh
• All Contributors

License

The MIT License (MIT). Please see License File for more information.