Struct bstr::FinderReverse
source · pub struct FinderReverse<'a>(/* private fields */);
Expand description
A single substring reverse searcher fixed to a particular needle.
The purpose of this type is to permit callers to construct a substring
searcher that can be used to search haystacks without the overhead of
constructing the searcher in the first place. This is a somewhat niche
concern when it’s necessary to re-use the same needle to search multiple
different haystacks with as little overhead as possible. In general, using
ByteSlice::rfind
or
ByteSlice::rfind_iter
is good enough, but FinderReverse
is useful when you can meaningfully
observe searcher construction time in a profile.
When the std
feature is enabled, then this type has an into_owned
version which permits building a FinderReverse
that is not connected to
the lifetime of its needle.
Implementations§
source§impl<'a> FinderReverse<'a>
impl<'a> FinderReverse<'a>
sourcepub fn new<B: ?Sized + AsRef<[u8]>>(needle: &'a B) -> FinderReverse<'a>
pub fn new<B: ?Sized + AsRef<[u8]>>(needle: &'a B) -> FinderReverse<'a>
Create a new reverse finder for the given needle.
sourcepub fn into_owned(self) -> FinderReverse<'static>
pub fn into_owned(self) -> FinderReverse<'static>
Convert this finder into its owned variant, such that it no longer borrows the needle.
If this is already an owned finder, then this is a no-op. Otherwise, this copies the needle.
This is only available when the std
feature is enabled.
sourcepub fn needle(&self) -> &[u8] ⓘ
pub fn needle(&self) -> &[u8] ⓘ
Returns the needle that this finder searches for.
Note that the lifetime of the needle returned is tied to the lifetime
of this finder, and may be shorter than the 'a
lifetime. Namely,
a finder’s needle can be either borrowed or owned, so the lifetime of
the needle returned must necessarily be the shorter of the two.
sourcepub fn rfind<B: AsRef<[u8]>>(&self, haystack: B) -> Option<usize>
pub fn rfind<B: AsRef<[u8]>>(&self, haystack: B) -> Option<usize>
Returns the index of the last occurrence of this needle in the given haystack.
The haystack may be any type that can be cheaply converted into a
&[u8]
. This includes, but is not limited to, &str
and &[u8]
.
§Complexity
This routine is guaranteed to have worst case linear time complexity
with respect to both the needle and the haystack. That is, this runs
in O(needle.len() + haystack.len())
time.
This routine is also guaranteed to have worst case constant space complexity.
§Examples
Basic usage:
use bstr::FinderReverse;
let haystack = "foo bar baz";
assert_eq!(Some(0), FinderReverse::new("foo").rfind(haystack));
assert_eq!(Some(4), FinderReverse::new("bar").rfind(haystack));
assert_eq!(None, FinderReverse::new("quux").rfind(haystack));
Trait Implementations§
source§impl<'a> Clone for FinderReverse<'a>
impl<'a> Clone for FinderReverse<'a>
source§fn clone(&self) -> FinderReverse<'a>
fn clone(&self) -> FinderReverse<'a>
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreAuto Trait Implementations§
impl<'a> Freeze for FinderReverse<'a>
impl<'a> RefUnwindSafe for FinderReverse<'a>
impl<'a> Send for FinderReverse<'a>
impl<'a> Sync for FinderReverse<'a>
impl<'a> Unpin for FinderReverse<'a>
impl<'a> UnwindSafe for FinderReverse<'a>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)