Struct LineIndex 

pub struct LineIndex { /* private fields */ }

Precomputed line offset index for efficient byte offset to line number conversion.

Building the index is O(n) in source length, but subsequent lookups are O(log n). Use this when you need to perform multiple line number lookups on the same source.

Example

use gruel_span::LineIndex;

let source = "line1\nline2\nline3";
let index = LineIndex::new(source);

assert_eq!(index.line_number(0), 1);  // Start of line 1
assert_eq!(index.line_number(6), 2);  // Start of line 2
assert_eq!(index.line_number(12), 3); // Start of line 3

Implementations

impl LineIndex

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

Build a line index from source text.

This scans the entire source once to find all newline positions. Time complexity: O(n) where n is the source length.

pub fn line_number(&self, offset: u32) -> usize

Get the 1-based line number for a byte offset.

Time complexity: O(log n) where n is the number of lines.

Panics

In debug builds, panics if offset exceeds the source length. In release builds, out-of-bounds offsets are clamped to the source length.

pub fn span_line_number(&self, span: Span) -> usize

Get the 1-based line number for a span’s start position.

pub fn line_col(&self, offset: u32) -> (usize, usize)

Get the 1-based line and column numbers for a byte offset.

Returns (line, column) where both are 1-indexed. The column is the number of bytes from the start of the line, plus 1.

Time complexity: O(log n) where n is the number of lines.

Panics

In debug builds, panics if offset exceeds the source length. In release builds, out-of-bounds offsets are clamped to the source length.

pub fn span_line_col(&self, span: Span) -> (usize, usize)

Get the 1-based line and column numbers for a span’s start position.

Returns (line, column) where both are 1-indexed.

pub fn line_count(&self) -> usize

Returns the number of lines in the source.

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.