Struct LineOffsetTable 

pub struct LineOffsetTable { /* private fields */ }

Converts byte offsets in source text to LSP Position values.

Precomputes line-start byte offsets once, then maps any byte offset to a (line, character) position. Characters are counted as UTF-16 code units as required by the LSP specification.

Implementations

impl LineOffsetTable

pub fn new(content: &str) -> LineOffsetTable

Builds the table for content.

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

Absolute byte offset where line (0-indexed) starts, or None if line is out of range.

Prefer this over re-deriving a line’s start via cursor arithmetic (cursor += line.len() + 1): str::lines() strips a trailing \r, so that approach under-counts by one byte per CRLF line and corrupts every subsequent offset in the file. This table is built by scanning char_indices() for \n (see new), which counts the \r, so it stays correct for LF, CRLF and mixed line endings alike.

Examples

use deps_core::lsp_helpers::LineOffsetTable;

let table = LineOffsetTable::new("a\r\nb\r\nc");
assert_eq!(table.line_start(0), Some(0));
assert_eq!(table.line_start(1), Some(3));
assert_eq!(table.line_start(2), Some(6));
assert_eq!(table.line_start(3), None);

pub fn byte_offset_to_position(&self, content: &str, offset: usize) -> Position

Converts a byte offset into an LSP Position.

pub fn position_to_byte_offset( &self, content: &str, position: Position, ) -> usize

Converts an LSP Position back into a byte offset — the inverse of byte_offset_to_position. Out-of-range lines or UTF-16 characters clamp to content.len() rather than panicking, matching the forward conversion’s .min(content.len()) guard.