Struct PostingHeader 

pub struct PostingHeader {
    pub count: u32,
    pub code_bytes: u32,
    pub stuck: u32,
}

The fixed part at the front of one partition’s image.

Fields

count: u32

How many members the partition holds.

code_bytes: u32

How many bytes one code takes.

Derivable from the root’s dim and bits, and stored anyway for the same reason dim is stored in a vector record: a partition can then be cut into its four arrays without the root, which is what a reader checking a file rather than opening one has.

stuck: u32

The size at which a split was tried and found there was no cut.

Part of the image because it is not derivable: it is the memory of a split that failed, and an image that dropped it would have every partition of identical vectors try to split again on the first write after an open.

Implementations

impl PostingHeader

pub fn encode(&self, into: &mut [u8]) -> Result<usize>

Writes the header into the front of into.

Errors

Code::Invalid if into is not long enough for the whole partition.

pub fn decode(bytes: &[u8]) -> Result<PostingHeader>

Reads a partition’s header back and checks the bytes behind it.

Errors

Code::Corrupt if a reserved field is set or if the buffer is not exactly the length the header describes.

pub const fn ids_at(&self) -> usize

Where the ids start.

pub const fn tags_at(&self) -> usize

Where the tags start.

pub const fn codes_at(&self) -> usize

Where the codes start.

pub const fn meta_at(&self) -> usize

Where the meta starts.

Trait Implementations

impl Clone for PostingHeader

fn clone(&self) -> PostingHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PostingHeader

impl Debug for PostingHeader

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

Formats the value using the given formatter.

impl Default for PostingHeader

fn default() -> PostingHeader

Returns the “default value” for a type.

impl Eq for PostingHeader

impl PartialEq for PostingHeader

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for PostingHeader