Struct ReedSolomon 

pub struct ReedSolomon { /* private fields */ }

A Reed-Solomon codec over GF(256) for codewords of at most 255 bytes.

The codec is parameterized by its error-correction capability: the number of byte errors it can correct, each costing two parity bytes. Codewords are laid out as parity || data.

Implementations

impl ReedSolomon

pub fn apply_corrections(target: &mut [u8], corrections: impl AsRef<[u8]>)

XORs corrections onto target, element-wise.

The two slices are zipped, so the tail of the longer one is ignored; a zero correction byte leaves its target byte unchanged.

impl ReedSolomon

pub fn apply_corrections_detached( parity: &mut [u8], data: &mut [u8], corrections: impl AsRef<[u8]>, )

Applies XOR corrections to a detached (parity, data) pair.

The corrections slice is laid out parity-first, matching the parity || data codeword layout: its first parity.len() bytes are XORed onto parity, and the remaining bytes onto data.

Like ReedSolomon::apply_corrections, this method uses truncating zip semantics. If corrections holds fewer bytes than parity and data combined, the uncovered tail is left unmodified; excess correction bytes are ignored.

impl ReedSolomon

pub fn compute_errors( &self, length: u8, syndromes: &Polynomial, ) -> Result<Option<Polynomial>, RSComputeErrorsError>

Computes errors in a received codeword.

Parameters

• length: full length of the codeword, including parity bytes
• syndromes: syndrome polynomial

Errors

• RSComputeErrorsError::GFError if an arithmetic operation fails
• RSComputeErrorsError::EuclideanError if the Euclidean algorithm fails
• RSComputeErrorsError::TooManyErrors if the input is unrecoverable
• RSComputeErrorsError::ZeroErrorLocatorDerivative if the error locator derivative evaluates to zero

impl ReedSolomon

pub fn compute_syndromes(num_parity_bytes: u8, received: &[u8]) -> Polynomial

Computes the syndromes of a given codeword.

impl ReedSolomon

pub fn compute_syndromes_detached( parity: &[u8], data: &[u8], ) -> Result<Polynomial, RSConstructorError>

Computes the syndromes of a given detached codeword.

An empty parity slice yields zero syndromes, so a pair carrying no parity always validates as pristine.

Errors

• RSConstructorError::ParityTooHigh is returned if parity holds more than MAX_PARITY_BYTES bytes.
• RSConstructorError::OddParityLength is returned if parity holds an odd number of bytes; parity always comprises two bytes per correctable error.

impl ReedSolomon

pub fn correct<'lt>( &self, received: &'lt [u8], ) -> Result<Cow<'lt>, RSDecodeError>

Corrects a received codeword, returning the corrected codeword.

Errors

• RSDecodeError::InsufficientLength is returned if received holds fewer bytes than ReedSolomon::parity_bytes.
• std::num::TryFromIntError is returned if received holds more than 255 bytes.
• ps_buffer::BufferError is returned if memory allocation fails.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the corrected bytes fail validation.

impl ReedSolomon

pub fn correct_detached<'lt>( parity: &[u8], data: &'lt [u8], ) -> Result<Codeword<'lt>, RSDecodeError>

Corrects a message based on detached parity bytes.

Errors

• RSConstructorError is returned if parity holds more than MAX_PARITY_BYTES bytes, or an odd number of bytes.
• std::num::TryFromIntError is returned if parity and data together hold more than 255 bytes.
• ps_buffer::BufferError is returned if memory allocation fails.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the corrected bytes fail validation.

impl ReedSolomon

pub fn correct_detached_data_in_place( parity: &[u8], data: &mut [u8], ) -> Result<(), RSDecodeError>

Corrects a message based on detached parity bytes.

Errors

• RSConstructorError is returned if parity holds more than MAX_PARITY_BYTES bytes, or an odd number of bytes.
• std::num::TryFromIntError is returned if parity and data together hold more than 255 bytes.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the corrected bytes fail validation.

impl ReedSolomon

pub fn correct_detached_in_place( parity: &mut [u8], data: &mut [u8], ) -> Result<(), RSDecodeError>

Corrects a message based on detached parity bytes. Also corrects the parity bytes.

Errors

• RSConstructorError is returned if parity holds more than MAX_PARITY_BYTES bytes, or an odd number of bytes.
• std::num::TryFromIntError is returned if parity and data together hold more than 255 bytes.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the corrected bytes fail validation.

impl ReedSolomon

pub fn correct_in_place(&self, received: &mut [u8]) -> Result<(), RSDecodeError>

Corrects a received codeword in-place.

Errors

• RSDecodeError::InsufficientLength is returned if received holds fewer bytes than ReedSolomon::parity_bytes.
• std::num::TryFromIntError is returned if received holds more than 255 bytes.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the data is unrecoverable.

impl ReedSolomon

pub fn decode<'lt>( &self, received: &'lt [u8], ) -> Result<Codeword<'lt>, RSDecodeError>

Decodes a received codeword, correcting errors if possible.

Errors

• RSDecodeError::InsufficientLength is returned if received holds fewer bytes than ReedSolomon::parity_bytes.
• std::num::TryFromIntError is returned if received holds more than 255 bytes.
• ps_buffer::BufferError is returned if memory allocation fails.
• RSComputeErrorsError is propagated from ReedSolomon::compute_errors.
• RSDecodeError::TooManyErrors is returned if the corrected bytes fail validation.

impl ReedSolomon

pub fn encode(&self, message: &[u8]) -> Result<Buffer, RSEncodeError>

Encodes a message into a codeword.

Errors

• ps_buffer::BufferError is returned if memory allocation fails.
• RSEncodeError::RSGenerateParityError if parity generation fails.

impl ReedSolomon

pub fn generate_parity( &self, message: &[u8], ) -> Result<ParityBytes, RSGenerateParityError>

Generates parity bytes.

Errors

• RSGenerateParityError::SetCoefficients is returned if 2 * parity + message.len() exceeds 255.
• RSGenerateParityError::Division is returned if the generator polynomial is zero (not expected to occur).

impl ReedSolomon

pub const fn new(parity: u8) -> Result<Self, RSConstructorError>

Creates a new Reed-Solomon codec with the given error-correction capability.

Errors

• RSConstructorError::ParityTooHigh is returned if parity exceeds MAX_PARITY.

impl ReedSolomon

pub const fn parity(&self) -> u8

Returns the error-correction capability of this codec: the number of byte errors a codeword can recover from.

impl ReedSolomon

pub const fn parity_bytes(&self) -> u8

Returns the number of parity bytes per codeword: 2 * parity, two per correctable error.

impl ReedSolomon

pub fn validate(&self, received: &[u8]) -> Option<Polynomial>

Validates a received codeword.

Returns None if received is a valid codeword, or Some(syndromes) if errors are detected.

An input holding fewer bytes than ReedSolomon::parity_bytes, or more than Polynomial::MAX_COEFFICIENTS (255) bytes, can never be a valid codeword and always yields Some; for such inputs the contained syndrome polynomial may be zero and is not usable for error computation.

impl ReedSolomon

pub fn validate_detached( parity: &[u8], data: &[u8], ) -> Result<Option<Polynomial>, RSConstructorError>

Validates a segregated (parity, data) pair.

Returns Ok(None) if valid, or Ok(Some(syndromes)) if errors are detected. An empty parity slice carries no parity information, so a pair within the length bound validates trivially.

A pair whose combined length exceeds Polynomial::MAX_COEFFICIENTS (255) bytes can never be a valid codeword and always yields Ok(Some); for such inputs the contained syndrome polynomial may be zero and is not usable for error computation.

Errors

• RSConstructorError::ParityTooHigh is returned if parity holds more than MAX_PARITY_BYTES bytes.
• RSConstructorError::OddParityLength is returned if parity holds an odd number of bytes.

Trait Implementations

impl Clone for ReedSolomon

fn clone(&self) -> ReedSolomon

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ReedSolomon

impl Debug for ReedSolomon

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

Formats the value using the given formatter.

impl Eq for ReedSolomon

impl Hash for ReedSolomon

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for ReedSolomon

fn cmp(&self, other: &ReedSolomon) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for ReedSolomon

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for ReedSolomon

fn partial_cmp(&self, other: &ReedSolomon) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for ReedSolomon