Struct Postscript 

pub struct Postscript<'a> {
    pub _tab: Table<'a>,
}

The Postscript is guaranteed by the file format to never exceed 65528 bytes (i.e., u16::MAX - 8 bytes) in length, and is immediately followed by an 8-byte EndOfFile struct.

An initial read of a Vortex file defaults to at least 64KB (u16::MAX bytes) and therefore is guaranteed to cover at least the Postscript.

The reason for a postscript at all is to ensure minimal but all necessary footer information can be read in two round trips. Since the DType is optional and possibly large, it lives in its own segment. If the footer were arbitrary size, with a pointer to the DType segment, then in the worst case we would need one round trip to read the footer length, one to read the full footer and parse the DType offset, and a third to fetch the DType segment.

The segments pointed to by the postscript have inline compression and encryption specs to avoid the need to fetch encryption schemes up-front.

Fields

_tab: Table<'a>

Implementations

impl<'a> Postscript<'a>

pub const VT_DTYPE: VOffsetT = 4u16

pub const VT_LAYOUT: VOffsetT = 6u16

pub const VT_STATISTICS: VOffsetT = 8u16

pub const VT_FOOTER: VOffsetT = 10u16

pub unsafe fn init_from_table(table: Table<'a>) -> Self

pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr, A: Allocator + 'bldr>( _fbb: &'mut_bldr mut FlatBufferBuilder<'bldr, A>, args: &'args PostscriptArgs<'args>, ) -> WIPOffset<Postscript<'bldr>>

pub fn dtype(&self) -> Option<PostscriptSegment<'a>>

Segment containing the root DType flatbuffer.

pub fn layout(&self) -> Option<PostscriptSegment<'a>>

Segment containing the root Layout flatbuffer (required).

pub fn statistics(&self) -> Option<PostscriptSegment<'a>>

Segment containing the file-level Statistics flatbuffer.

pub fn footer(&self) -> Option<PostscriptSegment<'a>>

Segment containing the ‘Footer’ flatbuffer (required)

Trait Implementations

impl<'a> Clone for Postscript<'a>

fn clone(&self) -> Postscript<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Postscript<'_>

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

Formats the value using the given formatter.

impl<'a> Follow<'a> for Postscript<'a>

type Inner = Postscript<'a>

unsafe fn follow(buf: &'a [u8], loc: usize) -> Self::Inner

Safety

impl<'a> PartialEq for Postscript<'a>

fn eq(&self, other: &Postscript<'a>) -> 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 Verifiable for Postscript<'_>

fn run_verifier( v: &mut Verifier<'_, '_>, pos: usize, ) -> Result<(), InvalidFlatbuffer>

Runs the verifier for this type, assuming its at position pos in the verifier’s buffer. Should not need to be called directly.

impl<'a> Copy for Postscript<'a>

impl<'a> StructuralPartialEq for Postscript<'a>