Struct LineIndex 

pub struct LineIndex { /* private fields */ }

Maps byte offsets in a source string to line and column positions.

Lines and columns are 0-indexed internally. Use LineIndex::line_col to get a (line, col) pair and add 1 when displaying to users.

The index is built in O(n) time and each lookup is O(log n) via binary search. This struct is intentionally dependency-free so it can be reused by WASM bindings, an LSP server, or any other consumer.

Implementations

impl LineIndex

pub fn new(text: &str) -> Self

Build a LineIndex from source text.

pub fn line_col(&self, offset: usize) -> (usize, usize)

Convert a byte offset to a 0-indexed (line, column) pair.

If offset is past the end of the source, the last line is returned with the column clamped to the line length.

pub fn line_start(&self, line: usize) -> Option<usize>

Byte offset of the start of the given 0-indexed line.

Returns None if line is out of bounds.

pub fn line_count(&self) -> usize

Total number of lines (at least 1 for non-empty or even empty input).

Trait Implementations

impl Clone for LineIndex

fn clone(&self) -> LineIndex

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LineIndex

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

Formats the value using the given formatter.