std::boyer_moore_horspool_searcher
| Defined in header  <functional> | ||
| 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.
| Contents | 
[edit] 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 BinaryPredicateorHash.
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.
[edit] 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
[edit] See also
| searches for a range of elements (function template) | 


