Struct Alphabet 

pub struct Alphabet { /* private fields */ }

Represents an encoding alphabet with its characters and configuration.

An alphabet defines the character set and encoding mode used for converting binary data to text. Supports three modes: mathematical base conversion, chunked (RFC 4648), and byte-range mapping.

Implementations

impl Alphabet

pub fn new(chars: Vec<char>) -> Result<Self, String>

Creates a new alphabet with default settings (BaseConversion mode, no padding).

Arguments

• chars - Vector of characters to use in the alphabet

Errors

Returns an error if the alphabet is empty or contains duplicate characters.

pub fn new_with_mode( chars: Vec<char>, mode: EncodingMode, padding: Option<char>, ) -> Result<Self, String>

Creates a new alphabet with specified encoding mode and optional padding.

Arguments

• chars - Vector of characters to use in the alphabet
• mode - Encoding mode (BaseConversion, Chunked, or ByteRange)
• padding - Optional padding character (typically ‘=’ for RFC modes)

Errors

Returns an error if:

• The alphabet is empty or contains duplicates
• Chunked mode is used with a non-power-of-two alphabet size

pub fn new_with_mode_and_range( chars: Vec<char>, mode: EncodingMode, padding: Option<char>, start_codepoint: Option<u32>, ) -> Result<Self, String>

Creates a new alphabet with full configuration including byte-range support.

Arguments

• chars - Vector of characters (empty for ByteRange mode)
• mode - Encoding mode
• padding - Optional padding character
• start_codepoint - Starting Unicode codepoint for ByteRange mode

Errors

Returns an error if configuration is invalid for the specified mode.

pub fn from_str(s: &str) -> Result<Self, String>

Creates an alphabet from a string of characters.

Arguments

• s - String containing the alphabet characters

pub fn base(&self) -> usize

Returns the base (radix) of the alphabet.

For ByteRange mode, always returns 256. Otherwise returns the number of characters.

pub fn mode(&self) -> &EncodingMode

Returns the encoding mode of this alphabet.

pub fn padding(&self) -> Option<char>

Returns the padding character, if any.

pub fn start_codepoint(&self) -> Option<u32>

Returns the starting Unicode codepoint for ByteRange mode.

pub fn encode_digit(&self, digit: usize) -> Option<char>

Encodes a digit (0 to base-1) as a character.

Returns None if the digit is out of range.

pub fn decode_char(&self, c: char) -> Option<usize>

Decodes a character back to its digit value.

Returns None if the character is not in the alphabet.

Trait Implementations

impl Clone for Alphabet

fn clone(&self) -> Alphabet

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Alphabet

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

Formats the value using the given formatter.