Struct BlockOffsetIndex 

pub struct BlockOffsetIndex {
    pub entries: Arc<Vec<(OffsetMarker, u32)>>,
    pub total_bytes: u32,
    /* private fields */
}

Fields

entries: Arc<Vec<(OffsetMarker, u32)>>

(marker, byte_start) pairs sorted by byte_start ascending.

Wrapped in Arc so the per-edit snapshot path (which clones BlockOffsetIndex as part of Store::snapshot) does an O(1) pointer bump instead of an O(N) memcpy of the underlying Vec. Mutators in this impl block go through Arc::make_mut, which deep-clones the Vec only on the first write after the Arc has been shared (i.e., after a snapshot was taken). External callers see Arc<Vec<...>> which derefs transparently to &[...] for reads.

total_bytes: u32

Total byte length of the rope this index describes. The last entry extends from its byte_start to this value.

Implementations

impl BlockOffsetIndex

pub fn new() -> Self

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn total_bytes(&self) -> u32

pub fn set_total_bytes(&mut self, total: u32)

pub fn table_anchor_count(&self) -> usize

Number of OffsetMarker::TableAnchor entries currently indexed. O(1) via a maintained counter. Used to gate flow-position derivation: rope-derived positions match Block.document_position only when this is zero.

pub fn insert_at( &mut self, position: usize, marker: OffsetMarker, byte_start: u32, )

Insert a marker at a given byte position. The caller is responsible for keeping the byte_start ordered relative to neighbours — this method does NOT re-sort.

pub fn push(&mut self, marker: OffsetMarker, byte_start: u32)

Append a marker at the end (its byte_start must be ≥ the last entry’s byte_start).

pub fn push_block(&mut self, block_id: EntityId, byte_start: u32)

Convenience: register a block by id. Equivalent to push(OffsetMarker::Block(id), byte_start).

pub fn remove_at(&mut self, position: usize) -> (OffsetMarker, u32)

Remove the entry at the given position. Panics if out of bounds.

pub fn drain_inclusive( &mut self, start: usize, end_inclusive: usize, ) -> Vec<(OffsetMarker, u32)>

Remove a contiguous range of entries, equivalent to entries.drain(start..=end_inclusive) plus the matching marker_index maintenance. Returns the removed entries.

pub fn clear(&mut self)

Drop every entry and reset total_bytes to zero. Equivalent to *self = Self::default() but expressed as a method so callers don’t need to depend on Default.

pub fn rebuild_marker_index(&mut self)

Rebuild marker_index and table_anchor_count from entries. Use after bulk mutations that bypassed the maintenance methods (e.g. raw entries.push in test setup).

pub fn range_of(&self, marker: OffsetMarker) -> Option<(u32, u32)>

Byte range (start, end) of a marker. end is the next marker’s byte_start (or total_bytes for the last entry). Returns None if the marker is not indexed.

O(1) average via the marker_index map.

pub fn range_of_block(&self, block_id: EntityId) -> Option<(u32, u32)>

Byte range for a block-id specifically. Convenience for the common case.

pub fn range_with_successor( &self, marker: OffsetMarker, ) -> Option<(u32, u32, bool)>

Like range_of, but also reports whether the marker has a successor entry. Callers that need to strip the trailing inter-block \n boundary (e.g. block_content_via_store, block_char_length) use this to distinguish “end == next marker’s byte_start, with a real \n between us” from “end == total_bytes, no separator after”.

O(1) average via marker_index.

pub fn position_of(&self, marker: OffsetMarker) -> Option<usize>

Position of marker in entries. O(1) average via the marker_index cache. Returns None if the marker is not indexed.

pub fn marker_at_byte(&self, byte: u32) -> Option<OffsetMarker>

Marker whose byte range covers byte. Returns None if the index is empty or byte falls past total_bytes.

byte == total_bytes is treated as belonging to the last entry (this is the cursor-at-end-of-document case).

pub fn block_at_byte(&self, byte: u32) -> Option<EntityId>

Block id whose byte range covers byte, ignoring table-anchor markers. Returns None if no block covers the byte.

pub fn byte_to_marker_byte(&self, byte: u32) -> Option<(OffsetMarker, u32)>

Convert an absolute rope byte offset into (marker, byte_in_marker). Returns None for offsets past the end or for an empty index.

pub fn byte_to_block_byte(&self, byte: u32) -> Option<(EntityId, u32)>

Block-only variant of byte_to_marker_byte.

pub fn shift_after(&mut self, threshold: u32, delta: i32)

Shift every entry whose byte_start ≥ threshold by delta bytes, and adjust total_bytes by delta. Used after a rope insert (positive delta) or delete (negative delta) to keep the index in sync without a full rebuild.

entries is sorted by byte_start, so the affected suffix is located via partition_point (O(log n)) and only that suffix is walked.

Trait Implementations

impl Clone for BlockOffsetIndex

fn clone(&self) -> BlockOffsetIndex

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BlockOffsetIndex

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for BlockOffsetIndex

fn default() -> BlockOffsetIndex

Returns the “default value” for a type.

impl Eq for BlockOffsetIndex

impl PartialEq for BlockOffsetIndex

fn eq(&self, other: &BlockOffsetIndex) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for BlockOffsetIndex