Struct FoldIndex 

pub struct FoldIndex { /* private fields */ }

Sorted in canonical (start_row ASC, end_row DESC) order over a fold slice for O(log F) “is this row hidden by a closed fold” queries.

The O(log F) twin of folds.iter().any(|f| f.hides(row)). Closed folds’ (start_row, end_row] hidden ranges are merged into a disjoint union, and one partition_point over the merged ranges answers the query. Merging (not just sorting) is what keeps this correct for nested folds: a fold that starts inside an enclosing one can end before it while the enclosing fold still covers the query row, so “the last fold with start_row <= row” alone is not enough — that fold may have already ended while an earlier, longer one still hides the row.

Mirrors the TUI renderer’s FoldIndex (hjkl-buffer-tui render.rs) — the same merge, the same query, the same answers. That copy sorts its input defensively because its fold source is not guaranteed ordered; this one relies on the buffer’s canonical (start_row ASC, end_row DESC) ordering invariant (see crate::View::add_fold and crate::View::set_auto_folds) and skips the sort so the build stays O(F) — it runs per keystroke / per frame on hot paths. Debug builds assert the invariant, so feeding unsorted folds fails loudly in tests rather than silently mis-answering in release.

Implementations

impl FoldIndex

pub fn new(folds: &[Fold]) -> Self

Build the merged hidden-range index from a fold slice in canonical (start_row ASC, end_row DESC) order (the buffer invariant — see the type docs).

O(F): one filter pass over the folds, then a single merge pass.

pub fn hides_row(&self, row: usize) -> bool

True when row is hidden by a closed fold — the O(log F) twin of folds.iter().any(|f| f.hides(row)).

Trait Implementations

impl Clone for FoldIndex

fn clone(&self) -> FoldIndex

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FoldIndex

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

Formats the value using the given formatter.

impl Eq for FoldIndex

impl PartialEq for FoldIndex

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for FoldIndex