GY-63_MS5611/libraries/LUHN
2023-01-17 16:38:46 +01:00
..
.github 0.1.0 LUHN 2022-12-29 16:15:53 +01:00
examples 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
.arduino-ci.yml 0.1.0 LUHN 2022-12-29 16:15:53 +01:00
CHANGELOG.md 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
keywords.txt 0.1.0 LUHN 2022-12-29 16:15:53 +01:00
library.json 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
library.properties 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
LICENSE update license 2023-01-17 16:38:46 +01:00
LUHN.cpp 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
LUHN.h 0.1.1 LUHN 2022-12-30 12:21:53 +01:00
README.md 0.1.1 LUHN 2022-12-30 12:21:53 +01:00

Arduino CI Arduino-lint JSON check License: MIT GitHub release

LUHN

Arduino Library for calculating LUHN checksum.

Description

The LUHN algorithm is a checksum (a.k.a. mod 10) invented by Hans Peter Luhn in 1960. It is used to validate a variety of product ID's to detect typing errors an/of digit swaps. So it is not to secure a number but to prevent common mistakes when entering a code in a system. The LUHN check uses very few resources and is pretty fast.

Basic idea is to put all digits-1 through the formula and the output should equal the last digit.

Note: some LUHN validations uses the reversed product string.

Interface

#include "LUHN.h"
  • LUHN() constructor
  • bool isValid(char * buffer ) validates the code in the parameter buffer. The parameter buffer is a '\0' terminated char array. Length should be less than 254.
  • bool isValid(const char * buffer ) idem.
  • char generateChecksum(char * buffer) Returns the char '0'..'9' which is the checksum of the code in the parameter buffer. The parameter buffer is a '\0' terminated char array. Length should be less than 254.
  • bool generate(char * buffer, uint8_t length, char * prefix) Generates a char array including LUHN number with a defined prefix of max length. Returns false if the prefix exceeds length -1.

Stream

  • char add(char c) add char, return LUHN so far.
  • char reset() return last LUHN.

The internal counter for the stream interface is 16 bit. This limits the nr of add() calls to about 65530. (if this is a problem, make it an uinit32_t)

Future

must

  • update documentation

should

  • unit tests
  • look for optimization

could

  • uint32_t interface for up to 8 digit ID's (99.999.999)
    • isValid(uint32_t)
    • generateChecksum(uint32_t)
    • how about leading zero's