Struct CacheHeader 

pub struct CacheHeader {
    pub version: u8,
    pub column_count: u8,
    pub row_count: u64,
    pub created_at_us: u64,
    pub data_crc64: u64,
}

File header for the binary event cache.

Fields

version: u8

Format version (currently 1).

column_count: u8

Number of columns present.

row_count: u64

Number of events (rows) in the file.

created_at_us: u64

Wall-clock timestamp at cache creation (us since Unix epoch).

data_crc64: u64

CRC-64 over all column data bytes.

Implementations

impl CacheHeader

pub const fn new(row_count: u64, created_at_us: u64) -> Self

Create a new header for a file containing row_count events, created at created_at_us with a placeholder CRC.

pub fn encode(&mut self, cols: &CacheColumns) -> Result<Vec<u8>, CacheError>

Encode the header and all column data into a byte buffer.

The column offsets array is written immediately after the 32-byte header. Each column is then written at its recorded offset.

Errors

Returns CacheError if any column fails to encode.

pub fn decode(data: &[u8]) -> Result<(Self, CacheColumns), CacheError>

Decode a cache file from bytes, returning the header and column data.

Errors

Returns CacheError if:

• The magic bytes are wrong.
• The version is unsupported.
• The CRC does not match.
• Any column data is truncated or malformed.

Panics

Panics if fixed-size slice conversions fail, which cannot happen when the data length has already been validated.

Trait Implementations

impl Clone for CacheHeader

fn clone(&self) -> CacheHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CacheHeader

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

Formats the value using the given formatter.

impl PartialEq for CacheHeader

fn eq(&self, other: &CacheHeader) -> 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 Eq for CacheHeader

impl StructuralPartialEq for CacheHeader