Struct LineIndex 

pub struct LineIndex { /* private fields */ }

Line starts of one source text, to turn UTF-8 byte offsets (the unit of every crate::Span) into line/column positions in UTF-8 bytes, chars, or UTF-16 code units.

Built once in O(n); each lookup is O(log n) (binary searches over the line starts and the multi-byte characters), whatever the line length. Line breaks are \n, \r\n, and a lone \r (YAML 1.2.2 §5.4). An offset past the end, or inside a multi-byte character, has no position (None); nothing here panics.

use oneyaml_core::{ColumnUnit, LineCol, LineIndex};

let src = "a: 1\nb: \u{e9}\u{1F600}x\n";
let idx = LineIndex::new(src);
let x = src.find('x').unwrap();
assert_eq!(idx.line_col(x, ColumnUnit::Utf8), Some(LineCol::new(1, 9)));
assert_eq!(idx.line_col(x, ColumnUnit::Char), Some(LineCol::new(1, 5)));
assert_eq!(idx.line_col(x, ColumnUnit::Utf16), Some(LineCol::new(1, 6)));
assert_eq!(idx.line_col(x - 1, ColumnUnit::Char), None); // inside the emoji
assert_eq!(idx.line_col(src.len() + 1, ColumnUnit::Char), None);
// A text ending in a line break has an empty last line.
assert_eq!(idx.line_count(), 3);
assert_eq!(idx.line_start(1), Some(5));
assert_eq!(idx.line_start(3), None);

Implementations

impl LineIndex

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

Indexes src.

pub fn len(&self) -> usize

The length of the indexed text, in bytes.

pub fn is_empty(&self) -> bool

true for an empty text.

pub fn line_count(&self) -> usize

The number of lines (a text ending in a line break has an empty last line).

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

The byte offset where 0-based line line starts.

pub fn line_col(&self, offset: usize, unit: ColumnUnit) -> Option<LineCol>

The position of byte offset, its column counted in unit; None past the end or inside a multi-byte character. O(log n).

pub fn span(&self, span: Span, unit: ColumnUnit) -> Option<(LineCol, LineCol)>

The positions of a span’s start and end (see LineIndex::line_col).

Trait Implementations

impl Clone for LineIndex

fn clone(&self) -> Self

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.

impl Eq for LineIndex

impl Hash for LineIndex

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LineIndex

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for LineIndex