Struct SegmentFooter 

pub struct SegmentFooter {
    pub schema_hash: u64,
    pub column_count: u32,
    pub row_count: u64,
    pub profile_tag: u8,
    pub columns: Vec<ColumnMeta>,
}

Segment footer: contains all metadata needed to read any column.

Serialized as MessagePack at the end of the segment, followed by a 4-byte footer length (u32 LE) and a 4-byte CRC32C of the serialized footer bytes.

[...column blocks...][footer_msgpack][footer_len: u32 LE][footer_crc: u32 LE]

To read: seek to end - 8, read footer_len + footer_crc, seek to end - 8 - footer_len, read + verify CRC, deserialize footer.

Fields

schema_hash: u64

xxHash64 of the schema definition (for schema compatibility checks).

column_count: u32

Number of columns in this segment.

row_count: u64

Total number of rows across all blocks.

profile_tag: u8

Profile that wrote this segment (0 = plain, 1 = timeseries, 2 = spatial).

columns: Vec<ColumnMeta>

Per-column metadata (offsets, codecs, block stats).

Implementations

impl SegmentFooter

pub fn to_bytes(&self) -> Result<Vec<u8>, ColumnarError>

Serialize the footer to bytes with trailing length + CRC32C.

pub fn from_segment_tail(data: &[u8]) -> Result<Self, ColumnarError>

Parse a footer from the tail of a segment byte slice.

Reads footer_len and CRC from the last 8 bytes, then deserializes the footer and validates the CRC.

Trait Implementations

impl Clone for SegmentFooter

fn clone(&self) -> SegmentFooter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SegmentFooter

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SegmentFooter

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'__msgpack_de> FromMessagePack<'__msgpack_de> for SegmentFooter

fn read<R: Read<'__msgpack_de>>(reader: &mut R) -> Result<Self, Error>

where Self: Sized,

Reads the MessagePack representation of this value from the provided reader.

impl Serialize for SegmentFooter

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl ToMessagePack for SegmentFooter

fn write<W: Write>(&self, writer: &mut W) -> Result<(), Error>

Writes the MessagePack representation of this value into the provided writer.