Struct DammTable 

pub struct DammTable { /* private fields */ }

Damm quasi-group table for check digit calculation.

The table has the following properties:

• Each row is a permutation of 0..size
• Each column is a permutation of 0..size
• Diagonal is all zeros: table[i][i] = 0
• Anti-symmetric: table[a][b] != table[b][a] when a != b

Implementations

impl DammTable

pub fn new(size: usize) -> Self

Generate a quasi-group table for the given alphabet size.

The generated table guarantees:

• 100% detection of single-character errors
• 100% detection of adjacent transposition errors

Arguments

• size - The alphabet size (10-62)

Examples

use promocrypt_core::DammTable;

let table = DammTable::new(26);
assert_eq!(table.size(), 26);

pub fn size(&self) -> usize

Get the size of the table (alphabet size).

pub fn get(&self, row: usize, col: usize) -> u8

Get table value at position.

pub fn calculate(&self, chars: &[char], alphabet: &Alphabet) -> char

Calculate check digit for a sequence of characters (check digit at end).

Arguments

• chars - The characters to calculate check digit for (without existing check digit)
• alphabet - The alphabet used for character→index mapping

Returns

The check digit character from the alphabet.

pub fn calculate_for_start(&self, chars: &[char], alphabet: &Alphabet) -> char

Calculate check digit for start position.

Finds a check digit X such that processing [X, chars…] results in 0.

Arguments

• chars - The characters (check digit will be prepended)
• alphabet - The alphabet used for character→index mapping

Returns

The check digit character from the alphabet.

pub fn calculate_for_position( &self, chars: &[char], alphabet: &Alphabet, position: usize, ) -> char

Calculate check digit for arbitrary position in the code.

Finds a check digit X such that inserting X at position in chars results in a valid code (Damm validation returns 0).

Arguments

• chars - The characters (check digit will be inserted at position)
• alphabet - The alphabet used for character→index mapping
• position - Position where check digit will be inserted (0-based)

Returns

The check digit character from the alphabet.

pub fn calculate_str(&self, s: &str, alphabet: &Alphabet) -> char

Calculate check digit for a string.

pub fn validate(&self, code: &str, alphabet: &Alphabet) -> bool

Validate a code including its check digit.

The check digit is valid if processing the entire code (including check digit) results in 0.

Arguments

• code - The full code including check digit
• alphabet - The alphabet used

Returns

true if the check digit is valid, false otherwise.

pub fn to_bytes(&self) -> Vec<u8>

Serialize the table to bytes for storage.

pub fn from_bytes(bytes: &[u8]) -> Result<Self>

Deserialize table from bytes.

pub fn to_base64(&self) -> String

Serialize to base64 string for JSON storage.

pub fn from_base64(s: &str) -> Result<Self>

Deserialize from base64 string.

Trait Implementations

impl Clone for DammTable

fn clone(&self) -> DammTable

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DammTable

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for DammTable

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for DammTable

fn eq(&self, other: &DammTable) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for DammTable

Custom serialization for DammTable using base64

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for DammTable

impl StructuralPartialEq for DammTable