Struct AlignedVarLenOffsets 

pub struct AlignedVarLenOffsets<'a>(/* private fields */);

Slice of offsets to var-len members, in units of 2-byte words.

This type is intended as a demonstration of the VarLenMembers interface, and is used in testing and benchmarking.

Note that this visitor is not suitable for sum types, or for types which contain sums.

Units of 2-byte words because VarLenRef is 2-byte aligned. Note that VarLenRef is 4 bytes wide, but only 2-byte aligned.

The listed offsets must not overlap, i.e. there must be a gap of at least 2 between each offset.

For AlignedVarLenOffsets([n]), a 4-byte VarLenRef exists in each row at +2n bytes.

e.g.: AlignedVarLenOffsets([0, 4]) has: row >= 12 bytes,

• var-len ref at +0..4 bytes (i.e. +0..2 u16s).
• fixed-len field(s) at +4..8 bytes (i.e. +2..4 u16s).
• var-len ref at +8..12 bytes (i.e. +4..6 u16s).
• fixed-len field(s) at +12.. (i.e. +6.. u16s), if row_size > 12.

Implementations

impl<'a> AlignedVarLenOffsets<'a>

pub const fn from_offsets(offsets: &'a [u16]) -> Self

Returns an AlignedVarLenOffsets using offsets.

Trait Implementations

impl<'a> Clone for AlignedVarLenOffsets<'a>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl VarLenMembers for AlignedVarLenOffsets<'_>

unsafe fn visit_var_len<'this, 'row>( &'this self, row: &'row Bytes, ) -> Self::Iter<'this, 'row>

Safety

row must be 2-byte aligned.

row must be an allocation of at least 2n + 2 bytes, where n is the largest offset in self.

All callers of visit_var_len on a particular row must visit the same set of VarLenRefs, though they may do so through different implementors of VarLenMembers. E.g. it would be valid to use an AlignedVarLenOffsets to initialize a row, then later read from it using a hypothetical optimized JITted visitor, provided the JITted visitor visited the same set of offsets.

unsafe fn visit_var_len_mut<'this, 'row>( &'this self, row: &'row mut Bytes, ) -> Self::IterMut<'this, 'row>

Safety

row must be 2-byte aligned.

row must be an allocation of at least 2n + 2 bytes, where n is the largest offset in self.

All callers of visit_var_len on a particular row must visit the same set of VarLenRefs, though they may do so through different implementors of VarLenMembers. E.g. it would be valid to use an AlignedVarLenOffsets to initialize a row, then later read from it using a hypothetical optimized JITted visitor, provided the JITted visitor visited the same set of offsets.

type Iter<'this, 'row> = AlignedVarLenOffsetsIter<'this, 'row> where Self: 'this

The iterator type returned by VarLenMembers::visit_var_len.

type IterMut<'this, 'row> = AlignedVarLenOffsetsIterMut<'this, 'row> where Self: 'this

The iterator type returned by VarLenMembers::visit_var_len_mut.

impl<'a> Copy for AlignedVarLenOffsets<'a>