std::boyer_moore_horspool_searcher
Defined in header <functional>
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template< class RandomIt1, class Hash = std::hash<typename std::iterator_traits<RandomIt1>::value_type>, |
(since C++17) | |
A searcher suitable for use with the Searcher
overload of std::search that implements the Boyer-Moore-Horspool string searching algorithm.
boyer_moore_horspool_searcher
is CopyConstructible
and CopyAssignable
.
RandomIt1
must meet the requirements of RandomAccessIterator
.
Member functions
std::boyer_moore_horspool_searcher::boyer_moore_horspool_searcher
boyer_moore_horspool_searcher( RandomIt1 pat_first, RandomIt1 pat_last, |
||
Constructs a boyer_moore_horspool_searcher
by storing copies of pat_first
, pat_last
, hf
, and pred
, setting up any necessary internal data structures.
The value type of RandomIt1
must be DefaultConstructible
, CopyConstructible
and CopyAssignable
.
For any two values A
and B
of the type std::iterator_traits<RandomIt1>::value_type, if pred(A, B) == true, then hf(A) == hf(B) shall be true
.
Parameters
pat_first, pat_last | - | a pair of iterators designating the string to be searched for |
hf | - | a callable object used to hash the elements of the string |
pred | - | a callable object used to determine equality |
Exceptions
Any exceptions thrown by
- the copy constructor of
RandomIt1
; - the default constructor, copy constructor, or copy assignment operator of the value type of
RandomIt1
; or - the copy constructor or function call operator of
BinaryPredicate
orHash
.
May also throw std::bad_alloc if additional memory required for internal data structures cannot be allocated.
std::boyer_moore_horspool_searcher::operator()
template< class RandomIt2 > std::pair<RandomIt2,RandomIt2> operator()( RandomIt2 first, RandomIt2 last ) const; |
||
The member function called by the Searcher overload of std::search to perform a search with this searcher. RandomIt2
must meet the requirements of RandomAccessIterator
.
RandomIt1
and RandomIt2
must have the same value type.
Parameters
first, last | - | a pair of iterators designating the string to be examined |
Return value
If the pattern ([pat_first, pat_last)) is empty, returns make_pair(first, first)
.
Otherwise, returns a pair of iterators to the first and one past last positions in [first, last) where a subsequence that compares equal to [pat_first, pat_last) as defined by pred
is located, or make_pair(last, last)
otherwise.
Example
#include <iostream> #include <string> #include <algorithm> #include <functional> int main() { std::string in = "Lorem ipsum dolor sit amet, consectetur adipiscing elit," " sed do eiusmod tempor incididunt ut labore et dolore magna aliqua"; std::string needle = "pisci"; auto it = std::search(in.begin(), in.end(), std::boyer_moore_horspool_searcher( needle.begin(), needle.end())); if(it != in.end()) std::cout << "The string " << needle << " found at offset " << it - in.begin() << '\n'; else std::cout << "The string " << needle << " not found\n"; }
Output:
The string pisci found at offset 43
See also
searches for a range of elements (function template) |