Struct xi_rope::rope::BaseMetric

pub struct BaseMetric(_);

This metric let us walk utf8 text by code point.

BaseMetric implements the trait Metric. Both its measured unit and its base unit are utf8 code unit.

Offsets that do not correspond to codepoint boundaries are invalid, and calling functions that assume valid offsets with invalid offets will panic in debug mode.

Boundary is atomic and determined by codepoint boundary. Atomicity is implicit, because offsets between two utf8 code units that form a code point is considered invalid. For example, if a string starts with a 0xC2 byte, then offset=1 is invalid.

Trait Implementations

impl Metric<RopeInfo> for BaseMetric

fn measure(_: &RopeInfo, len: usize) -> usize

Return the size of the NodeInfo::L, as measured by this metric.

fn to_base_units(s: &String, in_measured_units: usize) -> usize

Returns the smallest offset, in base units, for an offset in measured units.

fn from_base_units(s: &String, in_base_units: usize) -> usize

Returns the smallest offset in measured units corresponding to an offset in base units.

fn is_boundary(s: &String, offset: usize) -> bool

Return whether the offset in base units is a boundary of this metric. If a boundary is at end of a leaf then this method must return true. However, a boundary at the beginning of a leaf is optional (the previous leaf will be queried).

fn prev(s: &String, offset: usize) -> Option<usize>

Returns the index of the boundary directly preceding offset, or None if no such boundary exists. Input and result are in base units.

fn next(s: &String, offset: usize) -> Option<usize>

Returns the index of the first boundary for which index > offset, or None if no such boundary exists. Input and result are in base units.

fn can_fragment() -> bool

Returns true if the measured units in this metric can span multiple leaves. As an example, in a metric that measures lines in a rope, a line may start in one leaf and end in another; however in a metric measuring bytes, storage of a single byte cannot extend across leaves.

impl Copy for BaseMetric

impl Clone for BaseMetric

fn clone(&self) -> BaseMetric

Returns a copy of the value.

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

Performs copy-assignment from source.