Struct Header 

pub struct Header {

    pub version: u8,
    pub flags: u8,
    pub metadata_offset: u64,
    pub metadata_len: u64,
    pub dictionary_offset: u64,
    pub dictionary_len: u64,
    pub root_dir_offset: u64,
    pub root_dir_len: u64,
    pub pyramid_meta_offset: u64,
    pub pyramid_meta_len: u64,
    pub dict_codec: u8,
    pub block_codec: u8,
    pub pyramid_levels: u16,
    pub quad_count: u64,
    pub term_count: u64,
    pub content_hash: [u8; 16],
    pub named_graphs_offset: u64,
    pub named_graphs_len: u64,
    pub schema_meta_len: u32,
    pub text_index_offset: u64,
    pub text_index_len: u64,
    pub build_info_offset: u64,
    pub build_info_len: u64,
    pub perms: PermSet,
    pub extra_sections: Vec<Section>,
}

Decoded file header. All multi-byte fields are little-endian on disk. The *_offset / *_len fields are a convenience view over the section directory (populated from it on parse, emitted back to it on serialize).

Fields

version: u8

Format version of the parsed file (currently MIN_STABLE_READ_VERSION through CURRENT_FORMAT_VERSION).

flags: u8

metadata_offset: u64

metadata_len: u64

dictionary_offset: u64

dictionary_len: u64

root_dir_offset: u64

root_dir_len: u64

pyramid_meta_offset: u64

pyramid_meta_len: u64

dict_codec: u8

block_codec: u8

pyramid_levels: u16

quad_count: u64

term_count: u64

content_hash: [u8; 16]

First 16 bytes of the blake3 content hash — an immutable validator.

named_graphs_offset: u64

Named-graphs section (0 if the file has only the default graph).

named_graphs_len: u64

schema_meta_len: u32

Byte length of the trailing schema-pyramid block within the pyramid-meta section (0 if none). A reader fetches only that block — at pyramid_meta_offset + pyramid_meta_len - schema_meta_len — for an index/dictionary/summary-free Tier-0 coherence check.

text_index_offset: u64

Full-text index section (0 if the file has none; built with rete build --text-index). See SectionKind::TextIndex.

text_index_len: u64

build_info_offset: u64

Build-conditions section (0 if absent). See SectionKind::BuildInfo: an opaque per-build record that is not covered by the content hash.

build_info_len: u64

perms: PermSet

Which index permutations the file’s index containers carry ([crate::index::PermSet]).

On disk this is one byte at [50], inside the reserved core span, and 0 means all six — so every file written before the mask existed decodes as PermSet::ALL and a full six-permutation build stays byte-identical to what it always was. A lean file writes its mask (0b000_0111 for SPO+POS+OSP), and its index container then holds three sections rather than six, which is what an older reader trips over.

extra_sections: Vec<Section>

Directory entries whose SectionKind this build doesn’t recognize, preserved verbatim. Empty for a file this crate wrote.

Implementations

impl Header

pub fn to_bytes(&self) -> [u8; 1024]

Serialize into a fixed 1024-byte array.

pub fn from_bytes(b: &[u8]) -> Result<Self, HeaderError>

Parse a header from the first 1024 bytes of a file.

pub fn has_quads(&self) -> bool

pub fn expected_file_len(&self) -> Option<u64>

The total file length implied by this header alone: the writer lays the sections out back-to-back after the 1 KiB header and ends the file with the 4-byte RETE footer, so the furthest offset + length in the section directory plus 4 is the file length.

This is the one length signal a remote reader can always trust: an HTTP host may advertise the size of a compressed representation in Content-Length (GitHub Pages gzips — a 71 MB file HEADs as 58 MB) while serving ranges over the identity bytes, and may hide Content-Range from cross-origin JS by omitting Access-Control-Expose-Headers. The header travels in band — in the first 1 KiB range read — so it cannot be skewed by transport encoding.

None if any directory entry overflows u64 (a crafted or corrupt header must yield “unknown”, never a panic or a wrapped length — the weekly fuzz caught verify() on exactly this class of input).

pub fn has_quoted_triples(&self) -> bool

Does the file contain RDF-star quoted triples ([FLAG_HAS_QUOTED_TRIPLES])?

pub fn has_tile_synopsis(&self) -> bool

Do the tiled index sections carry a [FLAG_TILE_SYNOPSIS] trailer?

pub fn section(&self, kind: SectionKind) -> Option<Section>

The directory entry for a section kind, or None if absent. Known kinds read from the named convenience fields; unknown kinds from extra_sections.

pub fn with_section(self, kind: SectionKind, offset: u64, length: u64) -> Self

Attach (or overwrite) a section’s (offset, length) — the extension point for new top-level sections. Known kinds set the named fields; an unknown kind is appended to extra_sections.

Trait Implementations

impl Clone for Header

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Header

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

Formats the value using the given formatter.

impl Eq for Header

impl PartialEq for Header

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Header