Struct FileHeader 

pub struct FileHeader {
    pub magic: [u8; 8],
    pub version: u32,
    pub index_type: String,
    pub dim: usize,
    pub metric: DistanceMetric,
    pub n_vectors: usize,
    pub crc32: u32,
}

The header at the start of every iqdb snapshot file.

The on-disk representation is fixed-width little-endian — see the module-level docs for the byte-level layout. The Rust struct stores dim and n_vectors as usize for ergonomic in-memory use; the reader and writer convert to/from u64 at the wire boundary.

crc32 is the CRC32 of the payload bytes only — it does not cover the header.

Examples

use iqdb_persist::{FileHeader, CURRENT_VERSION, MAGIC};
use iqdb_types::DistanceMetric;

let header = FileHeader {
    magic: MAGIC,
    version: CURRENT_VERSION,
    index_type: "flat".to_string(),
    dim: 128,
    metric: DistanceMetric::Cosine,
    n_vectors: 1_000,
    crc32: 0xDEADBEEF,
};
assert_eq!(header.index_type, "flat");

Fields

magic: [u8; 8]

Magic bytes — always equal to MAGIC.

version: u32

On-disk format version. The reader accepts any version in MIN_SUPPORTED_VERSION..=CURRENT_VERSION and records which one it read here, so the payload can be decoded per that version.

index_type: String

Stable index-type tag — matched against crate::Persistable::INDEX_TYPE on load.

dim: usize

Dimensionality of the vectors stored in the payload.

metric: DistanceMetric

Distance metric the index was built for.

n_vectors: usize

Number of vectors stored in the payload.

crc32: u32

CRC32 of the payload bytes (not of the header).

Trait Implementations

impl Clone for FileHeader

fn clone(&self) -> FileHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FileHeader

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

Formats the value using the given formatter.

impl Eq for FileHeader

impl PartialEq for FileHeader

fn eq(&self, other: &FileHeader) -> 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 StructuralPartialEq for FileHeader