Function encode_coord_axis

nodedb-array/src/codec/coord_delta.rs:87–122

Encode one axis of a `DimDict` into a byte vector.

(dict: &DimDict, out: &mut Vec<u8>)

/// Encode one axis of a `DimDict` into a byte vector.
pub fn encode_coord_axis(dict: &DimDict, out: &mut Vec<u8>) -> ArrayResult<()> {
    // Dict entries: tag + count + values. Per-axis homogeneous-Int64 dicts
    // are batch-encoded with fastlanes; mixed/string dicts fall back to
    // per-value zerompk msgpack.
    if let Some(ints) = try_encode_int64_dict(&dict.values) {
        out.push(DICT_TAG_INT64_FASTLANES);
        out.extend_from_slice(&(ints.len() as u32).to_le_bytes());
        let encoded = nodedb_codec::fastlanes::encode(&ints);
        out.extend_from_slice(&(encoded.len() as u32).to_le_bytes());
        out.extend_from_slice(&encoded);
    } else {
        out.push(DICT_TAG_MSGPACK);
        let dict_count = dict.values.len() as u32;
        out.extend_from_slice(&dict_count.to_le_bytes());
        for cv in &dict.values {
            let bytes = zerompk::to_msgpack_vec(cv).map_err(|e| ArrayError::SegmentCorruption {
                detail: format!("coord dict encode: {e}"),
            })?;
            let len = bytes.len() as u32;
            out.extend_from_slice(&len.to_le_bytes());
            out.extend_from_slice(&bytes);
        }
    }

    // Index stream: count + zigzag-varint deltas.
    let idx_count = dict.indices.len() as u32;
    out.extend_from_slice(&idx_count.to_le_bytes());
    let mut prev: i64 = 0;
    for &idx in &dict.indices {
        let cur = idx as i64;
        let delta = cur - prev;
        write_varint(out, zigzag_encode(delta));
        prev = cur;
    }
    Ok(())
}

/// Decode one axis from `data[pos..]`, advancing `pos` past consumed bytes.
pub fn decode_coord_axis(data: &[u8], pos: &mut usize) -> ArrayResult<DimDict> {