Struct FileHeader 

pub struct FileHeader {

    pub magic: [u8; 4],
    pub version: u32,
    pub dimension: u32,
    pub language_count: u32,
    pub unit_count: u64,
    pub edge_count: u64,
    pub unit_table_offset: u64,
    pub edge_table_offset: u64,
    pub string_pool_offset: u64,
    pub feature_vec_offset: u64,
    pub temporal_offset: u64,
    pub index_offset: u64,
    pub repo_hash: [u8; 32],
    pub compiled_at: u64,
    pub _reserved: [u8; 8],
}

Header of an .acb file. Fixed size: 128 bytes.

Layout (all fields little-endian):

• 0x00: magic [u8; 4]
• 0x04: version u32
• 0x08: dimension u32
• 0x0C: language_count u32
• 0x10: unit_count u64
• 0x18: edge_count u64
• 0x20: unit_table_offset u64
• 0x28: edge_table_offset u64
• 0x30: string_pool_offset u64
• 0x38: feature_vec_offset u64
• 0x40: temporal_offset u64
• 0x48: index_offset u64
• 0x50: repo_hash [u8; 32]
• 0x70: compiled_at u64
• 0x78: _reserved [u8; 8]

Fields

magic: [u8; 4]

Magic bytes: must be [0x41, 0x43, 0x44, 0x42] (“ACDB”).

version: u32

Format version (currently 1).

dimension: u32

Feature vector dimensionality.

language_count: u32

Number of supported languages in this file.

unit_count: u64

Total number of code units.

edge_count: u64

Total number of edges.

unit_table_offset: u64

Byte offset to code unit table.

edge_table_offset: u64

Byte offset to edge table.

string_pool_offset: u64

Byte offset to string pool.

feature_vec_offset: u64

Byte offset to feature vectors.

temporal_offset: u64

Byte offset to temporal block.

index_offset: u64

Byte offset to index block.

repo_hash: [u8; 32]

Repository root path hash (for cache validation).

compiled_at: u64

Compilation timestamp (Unix epoch microseconds).

_reserved: [u8; 8]

Reserved for future use.

Implementations

impl FileHeader

pub fn new(dimension: u32) -> Self

Create a new header with sensible defaults and the given dimension.

pub fn write_to(&self, w: &mut impl Write) -> AcbResult<()>

Write the header to a byte writer (little-endian).

pub fn read_from(r: &mut impl Read) -> AcbResult<Self>

Read a header from a byte reader (little-endian).

Errors

• AcbError::InvalidMagic if magic bytes don’t match.
• AcbError::UnsupportedVersion if version is not recognized.
• AcbError::Io on read failure.

pub fn to_bytes(&self) -> [u8; 128]

Serialize the header to a 128-byte array.

pub fn from_bytes(data: &[u8; 128]) -> AcbResult<Self>

Deserialize a header from a 128-byte slice.

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 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 Copy for FileHeader

impl StructuralPartialEq for FileHeader