Struct PreparedIpc 

pub struct PreparedIpc(/* private fields */);

A prepared Arrow IPC fast-path encode.

Holds the computed layout and both framed message headers so the byte length (byte_len) and the encode (encode_into) share the work. A separate ipc_fast_path_len + encode_ipc_into pair, by contrast, runs the whole layout + flatbuffer build twice — once to size the sample and once to fill it. On the per-output send path that redundant work is independent of payload size, so it is a real fraction of the cost for high-frequency small/medium messages.

The emitted bytes are identical to encode_ipc_into.

Example

use dora_node_api::arrow_utils::decode_arrow_ipc;
use dora_node_api::arrow_utils::ipc_encode::PreparedIpc;
use dora_node_api::{IntoArrow, into_vec};

let data = vec![1u64, 2, 3].into_arrow();

// Prepare once, size the destination from `byte_len()`, then encode into it.
let prepared = PreparedIpc::new(&data).expect("primitive array is fast-path eligible");
let mut buffer = vec![0u8; prepared.byte_len()];
prepared.encode_into(&mut buffer)?;

// The buffer is a self-describing IPC stream, identical to `encode_ipc_into`.
let decoded = decode_arrow_ipc(&buffer)?;
assert_eq!(into_vec::<u64>(&decoded)?, vec![1, 2, 3]);

Implementations

impl PreparedIpc

pub fn new(array: &DoraArray) -> Option<Self>

Prepare the fast-path encode for array, or None if array is not fast-path eligible (fall back to encode_ipc_to_vec).

pub fn byte_len(&self) -> usize

Exact byte length of the IPC stream encode_into writes. Use it to size the (shared-memory) destination sample.

pub fn encode_into(&self, dst: &mut [u8]) -> Result<()>

Encode the complete IPC stream into dst, which must be exactly byte_len bytes. Copies each array buffer once.