Method iter_tile_versions

nodedb-array/src/segment/reader.rs:221–247

Returns an iterator over all tile versions for `hilbert_prefix` whose `system_from_ms <= system_as_of`, ordered **newest-first** by `system_from_ms`. Callers supply this to [`nodedb_array::query::ceiling`] to resolve the bitemporal ceiling for every coordinate in the prefix.

(
        &self,
        hilbert_prefix: u64,
        system_as_of: i64,
    )

    /// Callers supply this to [`nodedb_array::query::ceiling`] to resolve the
    /// bitemporal ceiling for every coordinate in the prefix.
    pub fn iter_tile_versions(
        &self,
        hilbert_prefix: u64,
        system_as_of: i64,
    ) -> ArrayResult<impl Iterator<Item = ArrayResult<(crate::types::TileId, TilePayload)>> + '_>
    {
        let tiles = &self.footer.tiles;

        // Find the contiguous slice of entries whose hilbert_prefix matches.
        let first = tiles.partition_point(|e| e.tile_id.hilbert_prefix < hilbert_prefix);
        let past_prefix = tiles.partition_point(|e| e.tile_id.hilbert_prefix <= hilbert_prefix);

        // Within [first..past_prefix], entries are ascending by system_from_ms.
        // Restrict to those at or before the cutoff.
        let cutoff_pos =
            tiles[first..past_prefix].partition_point(|e| e.tile_id.system_from_ms <= system_as_of);
        // Global index range: [first .. first+cutoff_pos).
        let qualifying_start = first;
        let qualifying_end = first + cutoff_pos;

        // Iterate in reverse (newest-first).
        let indices: Vec<usize> = (qualifying_start..qualifying_end).rev().collect();
        Ok(indices.into_iter().map(move |idx| {
            let tile_id = tiles[idx].tile_id;
            self.read_tile(idx).map(|payload| (tile_id, payload))
        }))
    }

    /// Decode tile #`idx`. CRC is checked by the framing layer.
    pub fn read_tile(&self, idx: usize) -> ArrayResult<TilePayload> {