Struct Chksum 

pub struct Chksum(/* private fields */);

A 31-bit checksum with validity marker

The checksum is computed using the DJB2 hash algorithm and masked to 31 bits. The most significant bit (bit 31) must be zero for a valid checksum, allowing quick detection of erased/uninitialized flash memory (which reads as 0xFF).

Implementations

impl Chksum

pub const SIZE: usize = 4usize

Size of the checksum in bytes (4 bytes for u32)

pub const fn zero() -> Self

Create a zero checksum

This is used as the initial previous checksum for the first savegame.

pub const fn hash(prev: Chksum, data: &[u8]) -> Self

Compute a checksum for the given data, chained with a previous checksum

Uses DJB2 hash algorithm. The previous checksum is included in the hash to create a chain of checksums linking savegames together.

Arguments

• prev - The checksum of the previous savegame
• data - The data to hash

pub const fn is_valid(&self) -> bool

Check if this checksum has a valid format

A valid checksum has its most significant bit set to zero. This allows quick detection of uninitialized flash (0xFF) or corrupted data.

pub const fn to_bytes(&self) -> [u8; 4]

Convert the checksum to big-endian bytes

pub const fn from_bytes(bytes: [u8; 4]) -> Self

Parse a checksum from big-endian bytes

Trait Implementations

impl Clone for Chksum

fn clone(&self) -> Chksum

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Chksum

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

Formats the value using the given formatter.

impl PartialEq for Chksum

fn eq(&self, other: &Chksum) -> 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 Copy for Chksum

impl Eq for Chksum

impl StructuralPartialEq for Chksum