Struct capnp::serialize::SegmentLengthsBuilder

pub struct SegmentLengthsBuilder { /* private fields */ }

Helper object for constructing an OwnedSegments or a SliceSegments.

Implementations

impl SegmentLengthsBuilder

pub fn with_capacity(capacity: usize) -> Self

Creates a new SegmentsLengthsBuilder, initializing the segment_indices vector with Vec::with_capacitiy(capacity). capacity should equal the number of times that push_segment() is expected to be called.

pub fn try_push_segment(&mut self, length_in_words: usize) -> Result<()>

Pushes a new segment length. The nth time (starting at 0) this is called specifies the length of the segment with ID n. If the segment overflows the total word count, then this returns a MessageSizeOverflow error.

pub fn into_owned_segments(self) -> OwnedSegments

Constructs an OwnedSegments, allocating a single buffer of 8-byte aligned memory to hold all segments.

pub fn into_slice_segments( self, slice: &[u8], segment_table_bytes_len: usize ) -> BufferSegments<&'_ [u8]>

Constructs a SliceSegments. slice contains the full message (including the segment header).

pub fn total_words(&self) -> usize

Returns the sum of the lengths of the segments pushed so far.

pub fn to_segment_indices(self) -> Vec<(usize, usize)>

Returns the vector of segment indices. Each entry is a pair (start_word_index, end_word_index). This method primarily exists to enable testing.