Struct Span

pub struct Span {
    pub start: usize,
    pub end: usize,
}

A representation of a range in a haystack.

A span corresponds to the starting and ending byte offsets of a contiguous region of bytes. The starting offset is inclusive while the ending offset is exclusive. That is, a span is a half-open interval.

A span is used to report the offsets of a match, but it is also used to convey which region of a haystack should be searched via routines like Input::span.

This is basically equivalent to a std::ops::Range<usize>, except this type implements Copy which makes it more ergonomic to use in the context of this crate. Indeed, Span exists only because Range<usize> does not implement Copy. Like a range, this implements Index for [u8] and str, and IndexMut for [u8]. For convenience, this also impls From<Range>, which means things like Span::from(5..10) work.

There are no constraints on the values of a span. It is, for example, legal to create a span where start > end.

Fields

start: usize

The start offset of the span, inclusive.

end: usize

The end offset of the span, exclusive.

Implementations

impl Span

pub fn range(&self) -> Range<usize>

Returns this span as a range.

pub fn is_empty(&self) -> bool

Returns true when this span is empty. That is, when start >= end.

pub fn len(&self) -> usize

Returns the length of this span.

This returns 0 in precisely the cases that is_empty returns true.

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

Returns true when the given offset is contained within this span.

Note that an empty span contains no offsets and will always return false.

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

Returns a new span with offset added to this span’s start and end values.

Trait Implementations

impl Clone for Span

fn clone(&self) -> Span

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Span

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

Formats the value using the given formatter.

impl From<Range<usize>> for Span

fn from(range: Range<usize>) -> Span

Converts to this type from the input type.

impl From<Span> for Range<usize>

fn from(span: Span) -> Range<usize>

Converts to this type from the input type.

impl Hash for Span

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 Index<Span> for [u8]

type Output = [u8]

The returned type after indexing.

fn index(&self, index: Span) -> &[u8]

Performs the indexing (container[index]) operation.

impl Index<Span> for str

type Output = str

The returned type after indexing.

fn index(&self, index: Span) -> &str

Performs the indexing (container[index]) operation.

impl IndexMut<Span> for [u8]

fn index_mut(&mut self, index: Span) -> &mut [u8]

Performs the mutable indexing (container[index]) operation.

impl PartialEq<Range<usize>> for Span

fn eq(&self, range: &Range<usize>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq<Span> for Range<usize>

fn eq(&self, span: &Span) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for Span

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Span

impl Eq for Span

impl StructuralPartialEq for Span